Method and device for conveying and positioning workpieces

Abstract

Method for conveying and positioning workpieces (62, 64), in which the workpieces (62, 64) are conveyed on a continuous conveyor device (60) in a through-flow direction (A), wherein in a position correction step at least one first workpiece (62) is positioned relative to at least one second workpiece (64), which maintains its position on the continuous conveyor device (60) in such a way that the at least one first workpiece (62) and the at least one second workpiece (64) assume a defined orientation relative to one another on the continuous conveyor device (60), and in a subsequent transfer step the at least one first workpiece (62) and the at least one second workpiece (64) are simultaneously picked up by a transfer device (40) from a pick-up position (P1) in their defined orientation by the continuous conveyor device (60) and transferred to a defined deposit position (P2).

Description

[0001] The present invention relates to a method for conveying and positioning workpieces, as well as a corresponding device.

[0002] In many manufacturing processes, workpieces are sequentially placed into various processing stations, from which they are removed in a further processed state and transported further. For example, such a processing station might be a press in a press line, in which essentially plate-shaped workpieces are processed in successive pressing steps. The workpieces are first conveyed toward a press on a continuous conveyor system, picked up by the continuous conveyor system, and inserted into the press. This continuous conveyor system might, for example, be, but is not limited to, a conveyor belt on which the workpieces are conveyed sequentially.

[0003] To optimize the workflow and processing speed in such a press line, it is advantageous to first align the workpiece on the conveyor belt in a position correction step before it is picked up by a transfer device in a subsequent transfer step and transferred to a defined deposit position in the press. This is particularly necessary if the transfer device performing the transfer step is equipped to pick up and transfer multiple workpieces simultaneously. The workpieces to be picked up simultaneously must then assume a defined orientation relative to each other on the conveyor belt before the transfer step can be performed.

[0004] EP 2 190 604 B1 discloses such a method, in which the position correction step, which precedes the transfer step for transferring the workpiece(s) into the press, is performed by a positioning device arranged next to the conveyor belt and operating independently of the transfer device. The positioning device presented in this prior art is formed, for example, by an articulated-arm robot that can pick up a single part from the conveyor belt and correct its position. The possibility of correcting the positions of several workpieces simultaneously using two positioning devices is also presented, which involves increased effort and correspondingly high costs.

[0005] DE 10 2017 111 800 A1 discloses a method for aligning two workpieces to form a joint, wherein in a longitudinal alignment step the first workpiece is aligned relative to the second workpiece along at least one of the workpiece edges by linear movement of at least one of the grippers relative to the respective other gripper, and wherein the longitudinal alignment step is carried out during the transport of the workpieces from the supply station to the processing station.

[0006] It is therefore an object of the present invention to further develop such a method for conveying and positioning workpieces in such a way that the simultaneous handling of several workpieces by a single conveying device is possible with comparatively little effort.

[0007] This object is achieved according to the invention by a method according to claim 1 and by a corresponding device according to claim 6.

[0008] According to the invention, in the position correction step, at least one first workpiece is positioned relative to at least one second workpiece. The latter maintains its position on the continuous conveyor, i.e., it is not subjected to any position correction. Only the at least one workpiece is thus arranged such that, after the position correction, the at least one workpiece and the at least second workpiece assume a defined orientation relative to one another, from which both workpieces can be transferred to the defined deposit position in the subsequent transfer step.

[0009] In this case, it is no longer necessary to correct the position of all workpieces being transferred in the transfer step; instead, only some of these workpieces are corrected relative to the remaining part. In the simplest case, a single first workpiece is repositioned relative to a single second workpiece. However, several first workpieces can also be positioned relative to a second workpiece, several second workpieces, or several first workpieces can be positioned relative to one or more second workpieces. All of these cases are intended to be covered by the formulations "at least one first workpiece" and "at least one second workpiece."

[0010] A positioning device that performs position correction therefore only needs to be configured to detect some of the workpieces to be transferred and position them relative to the remaining workpieces. This significantly simplifies the design of the entire system.

[0011] Preferably, prior to the position correction step, the actual positions of the at least one first workpiece and the at least one second workpiece on the continuous conveyor are optically detected. This can be done, for example, by an image capture device or another type of optical scanning device, either during the continuous passage of the continuous conveyor or while the continuous conveyor interrupts its operation for a brief moment.

[0012] Further preferably, target positions of the at least one workpiece and the at least one second workpiece are determined from the detected actual positions, which result in a common defined alignment.

[0013] Further preferably, based on the detected actual positions, the at least one first workpiece is determined to be positioned relative to the at least one second workpiece in the position correction step. Advantageously, a decision is therefore made as to which of the workpieces to be transferred will be repositioned relative to the remaining workpiece(s). Naturally, it is advantageous to select one or more workpieces that require the shortest distance for position correction or whose repositioning requires the fewest movements. In this way, the execution of the position correction step can be optimized in terms of time and energy.

[0014] According to a further preferred embodiment of the method according to the invention, the transfer device corrects the common spatial orientation of the at least one workpiece and the at least one second workpiece during the transfer step. This means that, for example, an angular orientation of the workpieces to be transferred is corrected during transfer to the defined deposit position, while the relative angular orientation of the at least one first workpiece to at least one second workpiece remains unchanged. A correction in the form of a common translational movement of the two workpieces is also possible.

[0015] The present invention further relates to a device for conveying and positioning workpieces, comprising - a continuous conveyor system for transporting workpieces in one direction, - a positioning device which is arranged on the continuous conveyor device and comprises means for positioning at least one first workpiece relative to at least one second workpiece, - an optical detection device which is designed to optically detect actual positions of the at least one first workpiece and the at least one second workpiece on the continuous conveyor device and to output data corresponding to the detected actual positions, - a control device which is configured to control the positioning device on the basis of the data corresponding to the detected actual positions, such that the positioning device positions the at least one first workpiece relative to the at least one second workpiece such that the at least one first workpiece and the at least one second workpiece together assume a defined orientation relative to one another, - and a transfer device which is configured to simultaneously pick up the at least one first workpiece and the at least one second workpiece from a pick-up position in their defined orientation and to transfer them into a defined storage position.

[0016] Preferably, the transfer device is configured to correct the spatial orientation of the at least one first workpiece and the at least one second workpiece in the picked-up state.

[0017] In the following, a preferred embodiment of the present invention is explained in more detail with reference to the drawing. Fig. 1 and Fig. 2 show an embodiment of a device according to the invention for conveying and positioning workpieces in two different positions, each in a schematic plan view.

[0018] Fig. Figure 1 is a plan view of the initial area of ​​a press line comprising a press 12 with four press stands 16, 18, 20, 22 and a lower tool 32 arranged therein. Workpieces are pressed between this lower tool 32 and an upper tool (not shown) located above it. A transfer device 40 is used to load the press 12, which removes workpieces from a continuous conveyor device, in this case a conveyor belt 60, and transports them in a throughput direction A (in Fig. 1 by an arrow), into the press 12 and deposited there. For this purpose, the conveyor belt 60 transports the workpieces in the throughput direction A into an area from which several workpieces can be simultaneously picked up by the transfer device 40 from a receiving position P1 and transferred to a deposit position P2 on the lower tool 32 of the press 12. In the present embodiment, two workpieces 62, 64 are gripped and transferred by the transfer device 40. In Fig. 1 also shows a pair of workpieces 74 which have just been transferred to the storage position P2.

[0019] For this purpose, the transfer device 40 comprises an arm 42, at the end of which a tool holder with a tooling 50 for gripping the workpieces 62, 64 is attached. The tooling 50 is adapted to the respective workpieces 62, 64 and has, for example, vacuum suction cups or the like to suction the workpieces 62, 64 and move them from the pick-up position P1 to the deposit position P2. The arm 42 extends radially from a vertical axis Z1 and is pivotable about this axis Z1. Furthermore, the arm 42 is movable in its direction of extension relative to the axis Z1, so that the end of the arm 42, which carries the tooling 50, can be moved closer to or further away from the axis Z1. For this purpose, the arm 42 is mounted in a corresponding holder 46, which enables the pivoting and the above-described movement of the arm 42 relative to the axis Z1.The holder 46 itself is movable along a rail 44 extending in the feed direction A. This allows the holder 46 to be moved with the arm 42 toward the press 12 and in the opposite direction toward the conveyor belt 60. An upward and downward movement of the arm 42 along the axis Z1 is also possible in order to lift the workpieces 62, 64 from the conveyor belt 60 and lower them onto the lower tool 32.

[0020] In order for the workpieces 62, 64 to be transferred to be correctly grasped by the tooling 50 of the transfer device 40, it is necessary for them to assume a defined alignment with one another at the end of the conveyor belt 60 in the pick-up position P1. To ensure this, a positioning device 66 in the form of an articulated-arm robot is provided, which is arranged next to the conveyor belt 60. At the end of its articulated arm 68, the robot carries a tooling 70 for picking up a workpiece. If two workpieces 62 and 64 lying next to one another on the conveyor belt 60 pass the section of the conveyor belt 60 next to which the articulated-arm robot 66 is arranged, the robot can grasp and transfer one of the two workpieces 62 or 64, i.e., lift it onto the conveyor belt 60 and place it again in a corrected position.In the present case, the articulated-arm robot 66 is capable of either correcting the position of a first workpiece, in this case the workpiece designated by the reference number 62, or of the other workpiece 64.

[0021] The process of positioning a first workpiece 62 relative to a second workpiece 64, which maintains its position on the conveyor belt, will hereinafter be referred to as a position correction step. Upon completion of this position correction step, both workpieces—that is, the first workpiece 62 with its position corrected and the second workpiece 64, which maintains its position on the conveyor belt 60—are jointly in a defined alignment relative to one another. If this is the case, the transfer device 40 can perform a transfer step in which the first workpiece 62 and the second workpiece 64 are simultaneously picked up from the pick-up position P1 and transferred to the deposit position P2.

[0022] To perform the position correction step, the actual positions of the first workpiece 62 and the second workpiece 64 on the conveyor belt 60 are first detected. This is achieved using an optical detection device 72, which may be, for example, an image recognition system. This is capable of outputting data representing the actual positions to a control device (not shown in detail), which is configured to control the articulated-arm robot 66.

[0023] From the actual positions, the control device determines target positions of the first workpiece 62 and the second workpiece 64, which together correspond to the defined alignment. The control device can then control the articulated-arm robot 66 such that it controls the first workpiece 62 and performs a position correction, i.e., corrects its position relative to the second workpiece 64. The position of the second workpiece 64 thus represents the reference position relative to which the position of the first workpiece 62 is changed.

[0024] In particular, the control device can be designed to select from the two workpieces 62 and 64 the one whose position correction requires the least amount of time and energy, ie, for whose position correction as few movements as possible must be performed by the articulated-arm robot 66. In other words, the data relating to the actual positions of two workpieces is used to determine which workpiece is to be moved (as the first workpiece) in relation to the other (second) workpiece.

[0025] In the embodiment in Fig. 1, the two workpieces 62 and 64 are designed as square plates with identical dimensions. In order for them to be correctly grasped by the tooling 50 of the transfer device 40, they must be aligned with each other in the defined orientation such that their edges are aligned and have a predetermined distance from each other. The two workpieces 62 and 64 must therefore be aligned with respect to their angular position and their distance from each other.

[0026] For this purpose, the Fig. 1 upper workpiece is selected as the first workpiece 62, grasped by the articulated-arm robot 66, rotated into a correct angular position relative to the second workpiece 64, and shifted until the defined alignment is achieved. In this alignment, the two workpieces 62 and 64 reach their pick-up position P1, where they are picked up by the transfer device 40. If necessary, the workpieces 62, 64, which are aligned in a defined manner relative to one another on the conveyor belt 60, must be transported further by the conveyor belt 60 until they reach the pick-up position P1.

[0027] For correct placement in the placement position P2 within the press, however, an angular correction of the two workpieces 62 and 64 must still be performed, while maintaining their relative position to one another, i.e., their angular orientation and their distance from one another. While the latter is ensured by the tooling 50 of the transfer device 40, a rotational movement of the tooling 50 can be performed during the transfer from the conveyor belt 60 into the press 12 to correct the angle between the pick-up position P1 and the placement position P2. This can be achieved through combined movements of the transfer device 40. Furthermore, additional translational movements of the two workpieces 62 and 64 can be performed during the transfer.

[0028] In Fig. 1, the position correction step is completed, i.e., the first workpiece 62 and the second workpiece 64 assume the receiving position P1, in which they have their defined alignment to one another, while the transfer device 40 deposits a pair of workpieces 74, which are still running ahead in the direction of travel A, into the press 12. After forming in the press 12, this pair is removed by a further conveyor device (not shown in detail) and transported further.

[0029] In Fig. 2 shows how the transfer device 40 has pivoted its arm 42 with the tooling 50 over the first workpiece 62 and the second workpiece 64 in the receiving position in order to grasp both workpieces 62, 64 simultaneously and transfer them to the defined storage position P2.

[0030] In the Fig. 1 and Fig.In the case illustrated in Figure 2, only two workpieces 62, 64 are picked up simultaneously in the transfer step and transferred to the press 12. Accordingly, only a single first workpiece 62 needs to be corrected in its position relative to a single second workpiece 64. However, the present invention is not limited thereto. It is also possible to correct the position of several first workpieces 62 relative to one or more second workpieces 64. The articulated-arm robot 66 then grasps several first workpieces 62 and positions them relative to the second workpieces 64.

Claims

[1] Method for conveying and positioning workpieces (62, 64), in which the workpieces (62, 64) are conveyed on a continuous conveyor device (60) in a through-flow direction (A), wherein in a position correction step at least one first workpiece (62) is positioned relative to at least one second workpiece (64), which maintains its position on the continuous conveyor device (60) in such a way that the at least one first workpiece (62) and the at least one second workpiece (64) assume a defined orientation relative to one another on the continuous conveyor device (60), and in a subsequent transfer step the at least one first workpiece (62) and the at least one second workpiece (64) are simultaneously picked up by a transfer device (40) from a pick-up position (P1) in their defined orientation by the continuous conveyor device (60) and transferred to a defined deposit position (P2). [2] Method according to claim 1, characterized by that before the position correction step, actual positions of the at least one first workpiece (62) and the at least one second workpiece (64) on the continuous conveyor device (60) are optically detected. [3] Method according to claim 2, characterized by that target positions of the at least one first workpiece (62) and the at least one second workpiece (64) are determined from the detected actual positions, which result in a common defined alignment. [4] Method according to claim 3, characterized by that on the basis of the detected actual positions, the at least one first workpiece (62) is determined, which is positioned in the position correction step relative to the at least one second workpiece (64). [5] Method according to one of the preceding claims, characterized bythat the transfer device (40) corrects the common spatial orientation of the at least one first workpiece (62) and the at least one second workpiece (64) in the transfer step. [6] Device for conveying and positioning workpieces (62, 64), comprising: a continuous conveyor device (60) for conveying workpieces (62,64) in a throughput direction (A), a positioning device (66) arranged on the continuous conveyor device (60) and means for positioning at least one first workpiece (62) relative to at least one second workpiece (64), an optical detection device (72) which is designed to optically detect actual positions of the at least one first workpiece (62) and the at least one second workpiece (64) on the continuous conveyor device (60) and to output data corresponding to the detected actual positions, a control device which is configured to control the positioning device (66) on the basis of the data corresponding to the detected actual positions, such that the positioning device (66) positions the at least one first workpiece (62) relative to the at least one second workpiece (64) on the continuous conveyor device (60) such that the at least one first workpiece (62) and the at least one second workpiece (64) together assume a defined orientation relative to one another, and a transfer device (40) which is configured to simultaneously pick up the at least one first workpiece (62) and the at least one second workpiece (64) from a pick-up position (P1) on the continuous conveyor device (60) in their defined orientation and to transfer them to a defined deposit position (P2). [7] Device according to claim 6, characterized bythat the transfer device (40) is designed to correct the spatial orientation of the at least one first workpiece (62) and the at least one second workpiece (64) in the picked-up state.

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