Method of aligning an upper and a lower changeable tool, and device for processing workpiece sheets

Abstract

In a method of aligning an upper and a lower changeable tool (2, 10, 18) in a device for processing, e.g., sheets of paper, provision is made that with the aid of at least one digital camera (50, 51), the upper changeable tool (2) is aligned with a sheet that has been moved in and the lower changeable tool (18) is aligned relative to the upper changeable tool (2) after the sheet has been moved out.

Claims

1. A method of aligning an upper changeable tool and a lower changeable tool in a device for processing cardboard or plastic packaging workpiece sheets, the method comprising: inserting the lower changeable tool into a holder on a device side, the lower changeable tool and the upper changeable tool configured to perform at least a part of the processing; moving a sheet of the workpiece sheets into the device until the sheet lies above the lower changeable tool; inserting the upper changeable tool into a holder on the device side releasably inserting at least one camera in a form-fitting seat on the upper changeable tool, aligning the upper changeable tool in relation to the sheet with the aid of the at least one camera; removing the sheet; aligning the lower changeable tool in relation to the upper changeable tool with the aid of the at least one camera; providing the lower changeable tool with at least one mark that is adapted to be detected by the at least one camera, and using the at least one mark as a target position of the lower changeable tool to align with the upper changeable tool.

2. The method according to claim 1, wherein the at least one camera is introduced into the device for a time period of the aligning, and the method further comprises: removing the camera from the device after the alignment.

3. The method according to claim 1 further comprising: providing a plurality of the cameras, including the at least one camera, wherein a field of view of a first camera of the cameras covers an area that is a front edge area of the lower changeable tool in the feed direction of the sheet, and a field of view of a second camera of the cameras covers a rear edge area of the lower changeable tool.

4. The method according to claim 1, further comprising attaching the at least one camera to the device at such a distance from the changeable tools that a field of view of the at least one camera covers the upper changeable tool.

5. The method according to claim 4, further comprising attaching the at least one camera to a retainer configured for allowing displacement and alignment of the camera with respect to the upper changeable tool.

6. The method according to claim 4, further comprising: sensing by the camera an opening in the upper changeable tool for determining the position of the upper changeable tool, and sensing the lower changeable tool through the opening for aligning the upper and the lower changeable tools with respect to each other.

7. The method according to claim 1, wherein the aligning of the upper changeable tool in relation to the sheet comprises identifying marks provided on the sheet or edges, of a cut, produced on the sheet.

8. The method according to claim 1, wherein the aligning is performed with the aid of a display device in the form of a screen that is coupled to the at least one camera and reproduces the image captured by the at least one camera.

9. The method according to claim 8, further comprising loading an electronic mark added to the camera image into the screen to represent the current camera orientation.

10. The method according to claim 8, further comprising: performing the aligning manually either exclusively by means of the screen or by additionally using digital sensor units which are electronically coupled to the control unit of the device, determining the positions of parts that move during the setting of the associated changeable tool identifying alignment errors via the control unit on the basis of the image information received from the at least one camera, and outputting data for the display of at least one of the current misalignment and the target position to display devices in the form of displays which are integrated in the sensor units.

11. The method according to claim 1, wherein the aligning proceeds fully automatically, wherein the control unit activates motors for adjusting the changeable tools in order to bring the changeable tools into the target position.

12. The method according to claim 1, wherein the method is performed in a flat bed die-cutting device, a flat bed stripping device, an embossing device or a sheet printing device.

13. A device for processing cardboard or plastic packaging workpiece sheets, the device comprising: a processing station including a transport device for transporting the workpiece sheets through the processing station in succession; an upper changeable tool and a lower changeable tool, the changeable tools configured for the processing of the workpiece sheets, the changeable tools being configured to be fastened in holders on the device side and to be aligned with each other; a central electronic control unit for controlling the device; at least one digital camera coupled to the control unit and mounted in the processing station, such that when a sheet of the workpiece sheets has been moved in, the camera optically detects the sheet and, when the sheet has been moved out, the at least one camera optically detects the lower changeable tool; an adjustment device for independently aligning the upper and lower changeable tools with each other based on the optical detections; and at least one display device configured to reproduce a current alignment of the sheet that has been moved in, relative to the upper changeable tool and, when the sheet has been moved out, to reproduce the alignment of the lower changeable tool relative to the upper changeable tool; wherein the upper changeable tool includes a form-fitted seat configured to receive insertion of the at least one digital camera, and the lower changeable tool includes at least one mark configured to be detected by the at least one digital camera and marking a target position of the lower changeable tool aligned in relation to the upper changeable tool.

14. The device according to claim 13, wherein the adjustment device comprises manual adjustment devices.

15. The device according to claim 13, wherein the adjustment device comprises motor-driven adjustment devices which are coupled to the control unit and configured, after a misalignment has been detected, to bring the associated changeable tool into the target position, wherein the control unit is configured to automatically align the holders on the basis of the data received from the at least one camera.

16. The device according to claim 13, further comprising a display device including a screen for reproducing at least one of the camera image(s) and displays provided on sensor units of the adjustment device, wherein the control unit is configured to output on the display device information about at least one of the current position and the relation between the current position and the target position of the changeable tool.

17. A device for processing cardboard or plastic packaging workpiece sheets, the device comprising: an upper changeable tool and a lower changeable tool, the changeable tools configured for the processing of the workpiece sheets, the changeable tools being configured to be fastened in holders on the device side and to be aligned with each other; a central electronic control unit for controlling the device; a digital camera coupled to the control unit and mounted in the processing station, such that when a sheet of the workpiece sheets has been moved in, the digital camera optically detects the sheet and, when the sheet has been moved out, the digital camera optically detects the lower changeable tool; an adjustment device for independently aligning the upper and lower changeable tools with each other based on the optical detections; and at least one display device configured to reproduce a current alignment of the sheet that has been moved in, relative to the upper changeable tool and, when the sheet has been moved out, to reproduce the alignment of the lower changeable tool relative to the upper changeable tool, wherein the upper changeable tool defines a first opening therethrough, and the digital camera determines the position of the upper changeable tool and optically detects the lower changeable tool through the first opening, wherein the lower changeable tool defines a second opening therethrough, and the second opening has an opening area smaller than the opening area of the first opening so as to align the upper and the lower changeable tools with respect to each other.

18. A device for processing cardboard or plastic packaging workpiece sheets, the device comprising: an upper changeable tool and a lower changeable tool, the changeable tools configured for the processing of the workpiece sheets, the changeable tools being configured to be fastened in holders on the device side and to be aligned with each other; a central electronic control unit for controlling the device; a digital camera coupled to the control unit and mounted in the processing station, such that when a sheet of the workpiece sheets has been moved in, the digital camera optically detects the sheet and, when the sheet has been moved out, the digital camera optically detects the lower changeable tool; an adjustment device for independently aligning the upper and lower changeable tools with each other based on the optical detections; and at least one display device configured to reproduce a current alignment of the sheet that has been moved in, relative to the upper changeable tool and, when the sheet has been moved out, to reproduce the alignment of the lower changeable tool relative to the upper changeable tool, wherein the upper changeable tool defines a opening therethrough, and the digital camera determines the position of the upper changeable tool and optically detects the lower changeable tool through the opening, wherein the lower changeable tool includes a mark discernible by the digital camera through the opening so as to align the upper and the lower changeable tools with respect to each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a side view of a flat bed die-cutter which includes several devices according to the invention in the form of several stations,

(2) FIG. 2 shows a simplified side view of a variant of the device according to the invention in the form of a stripping station,

(3) FIG. 3 shows a holder in the form of a sliding frame for the device according to FIG. 2, a variety of changeable tools being adapted to be inserted into the holder,

(4) FIG. 4 shows a sectional view of the holder in the region of the upper changeable tool with a variant for the positioning of a camera, and

(5) FIG. 5 shows a top view of a sheet that has been moved in, in the region of a longitudinal end.

DESCRIPTION OF AN EMBODIMENT

(6) FIG. 1 shows a flat bed die-cutting press for processing workpiece sheets made of paper, cardboard including corrugated board, and plastic.

(7) The flat bed die-cutting press has a plurality of devices, also referred to as stations, through which the sheets that are fed in pass in succession.

(8) The flat bed die-cutting press comprises a so-called feeder 100, in which the sheets, stacked on one another, are introduced, an adjoining separator 102, in which the sheets are supplied to the subsequent stations of the flat bed die-cutting press one after the other, a cutting or embossing device 104, a stripping device 106, in which waste is separated from the sheet, and a blank separation device 108, in which the blanks are separated from the sheet. The devices 104-108 each have so-called upper and lower changeable tools 110-114 and 116-120, respectively, provided therein, which are aligned with each other in pairs to process sheets 122 located between them when they are closed.

(9) By way of example, FIG. 2 illustrates a variant of a stripping device 106 which has an upper changeable tool 2 with a so-called stripping board 3 which has stripping pins 4 attached to it that project downwards.

(10) The upper changeable tool 2 is releasably fastened to a holder 5 for the batch to be processed, the holder 5 being on the device side and illustrated in a simplified fashion. In the illustrated embodiment, the holder 5 is designed in the form of a laterally extensible carriage or sliding frame to which the stripping board 3 is fastened.

(11) In the illustrated embodiment, two lower changeable tools are shown, more specifically a changeable tool 10 in the form of a board from which telescopic pins 17 protrude which project upwards and are in alignment with the stripping pins 4.

(12) Since the provision of the changeable tool 10 is not absolutely necessary, the changeable tool 18 in the form of a stripping plate may be the only lower changeable tool. This stripping plate has openings which are adapted in terms of size and geometry to the die-cutting wastes and are positioned directly below the die-cutting wastes to be separated from the workpiece sheet lying above it. During separation, the tool closes, so that the upper changeable tool 2 travels downwards and the stripping pins 4 and the telescopic pins 17 optionally clamp the die-cutting wastes and eject them downwards through the openings in the stripping plate.

(13) Sheets of different formats or having different blanks always require separate specific changeable tools 2, 10, 18.

(14) The changeable tools 2, 10, 18 need to be inserted into their frame-type carriages, introduced into the device and precisely aligned there with each other and with the sheet.

(15) The holder 5 shown in FIG. 3 is illustrated as an example only; it may also be simpler in configuration. Further, it may also be employed for the changeable tools 10, 18 in a similar design.

(16) The holder 5 comprises a pair of carriers 20, 21 and transverse carriers 22, 23 which form a carrier structure. A front guide 24 and a rear guide 25, illustrated somewhat concealed, are adjustably attached to this carrier structure. The front guide 24 has a receiving groove 26 which extends over essentially the entire length of the guide 24. The rear guide 25 has a corresponding groove which faces the groove 26 and is not visible. The guides 24, 25 can be adjusted as desired by means of toothed racks, linkages and spindles in a plane parallel to the plane of the sheet 122 lying thereunder, namely in an X-direction (direction of the moving sheet), in a Y-direction, i.e. transversely to the X-direction, and in a rotational direction R. In addition, the distance between the guides 24, 25 can be varied by means of an adjustment means 27.

(17) Further adjustment means 28, 29 and 30 serve to align the guides 24, 25 in the X-, Y- and rotational R directions.

(18) The adjustment means 27-30 may be configured to be manual or motor-driven.

(19) Furthermore, sensor units 31-34 may be coupled to the adjustment means 27-30 and are used for detecting the respective positions of the corresponding adjustment means 27-30 and, in this way, the position of the guide 24, 25 or of the parts connected to and moving with it.

(20) Symbolically illustrated is one of the sensor units 31-34, which has a sensor 36 accommodated in its interior and may include a display device 38, here a display.

(21) The sensor units 31-34 are electronically coupled to a control unit 37 of the device or of the entire flat bed die-cutting press. An operating unit is denoted by 39.

(22) For aligning the upper changeable tool 2 with the lower changeable tool, in this case the changeable tool 18, one or two digital cameras 50, 51 is/are provided (see FIG. 2). In the illustrated embodiment, a camera 50 is provided in the front edge area in the feed direction A of the sheet 122 and the camera 51 is provided in the rear edge area of the changeable tool 2 (see FIG. 5).

(23) The cameras 50, 51 are coupled to the control unit 37 and may be inserted into the device only for aligning the changeable tools 2, 18. The stripping board 3 may, for example, have appropriate seats or mounting means for positioning the cameras 50, 51 quickly, securely and free of play. As an example, the upper changeable tool 2 has an opening 61 in the stripping board 3 (see FIG. 4) which can be used as a seat for inserting the camera 50 or 51. In an alternative, as shown in FIG. 4, the camera is fixed by a separate retainer 60. The retainer 60 can be temporarily (for the alignment process) or permanently (even during processing) fixed to the device (here: to the die-cutting press). Further, the retainer 60 may allow to displace the camera manually or automatically by motor drives within a plane parallel to the sheet 122 within the station or parallel to the stripping board 3.

(24) The cameras 50, 51 are positioned such that when a sheet 122 has been moved into the device 106, they can detect this sheet, and in the absence of the sheet, they can optically detect the lower changeable tool 18.

(25) FIG. 5 illustrates the sheet 122 for setting the upper changeable tool 2 in the area of the section that can be optically captured by the camera 50. It can be seen here that a mark 53 in the form of a cross, for example, has been permanently applied to the top side of the sheet.

(26) Such a mark 53 was also applied to the lower changeable tool 18 inside or outside the device after an optimum alignment of the upper and lower changeable tools 2, 10 with each other, e.g. burnt in using a laser. For example, the mark is precisely aligned with the seat for the camera 50 in the upper changeable tool 2.

(27) The method of aligning the upper and lower changeable tools 2, 10 and 18 will now be described below.

(28) First the lower changeable tool 18, possibly also the changeable tool 10, if necessary, is installed. Subsequently, the upper changeable tool 2 is installed, and a sheet 122 that was previously die-cut in the preceding station is moved into the device 106 by the flat bed die-cutting press.

(29) The sheet 122 may be a test sheet, for example, which has two marks 53, namely, one mark that corresponds to the mark 53 and a second mark in the area below the camera 51. These marks are positioned in a predetermined, fixed allocation to the edges of cut in the sheet 122 that were generated in the preceding station.

(30) Since the sheets can be positioned precisely and repeatably in the device 106 by means of grippers 124 guided through the flat bed die-cutting press by chains 126 (see FIG. 1) and by means of stops, the upper changeable tool 2 and then the lower changeable tool 18 merely have to be aligned with the sheet 122.

(31) This alignment is effected by means of the cameras 50, 51 and a display device (screen 55) that is coupled to the control unit 37 and displays the image captured by the cameras 50, 51. Additionally, a mark 57 for the camera 50 and a mark 59 for the camera 51 are electronically inserted in and shown on the screen 55, which represent the current camera orientation, i.e. the exact center of the camera 50, 51 and its rotational orientation.

(32) In this connection, it is important that the cameras 50, 51 are seated in their retainers repeatably and precisely not only in the radial direction, but also in the direction of rotation. As shown in FIG. 4, to this end the cameras 50, 51 may have eccentric extensions 58 that serve to determine the direction of rotation.

(33) Below the marks 57, 59, the screen 55 displays marks that are within the images of the cameras 50, 51, i.e. the marks on the lower changeable tool 18.

(34) It can be seen that there is a misalignment here, so that the two crosses, just as the two vertical lines in the area of the camera 51, have to be made to register with each other.

(35) Once the upper changeable tool 2 is aligned with the sheet or reference sheet that has been moved in, the sheet is removed and the cameras 50, 51 view the changeable tool 18 below, so that the corresponding marks on the lower changeable tool 18 are now displayed on the screen 55.

(36) The lower changeable tool 18 now has to be aligned with the upper changeable tool 2, which was aligned in an optimum manner previously. It should be emphasized that the reference sheet need not necessarily be provided with a mark of its own. It is also possible to perform the alignment by means of the edges of cut which were generated in the sheet in the preceding die-cutting station.

(37) The changeable tools 2, 10, 18 are aligned either purely manually by rotating the adjustment means 28-30 in the form of wheels as shown in FIG. 3 until the respective marks are exactly superimposed on the screen 55.

(38) Alternatively, when the screen 55 is too far away, the manual alignment may be done using the display devices 38 which are provided on the sensor units 32-34 (see FIG. 2).

(39) The control unit 37 detects the alignment errors using the image data which it has obtained from the cameras 50, 51, and sends corresponding, derived data to the display devices 38, where information is reproduced which indicates to the user the actual misalignment and/or the target position. For example, the target position may be indicated in the display (upper line in the display device 38 in FIG. 3) and the actual position under it. The operator then rotates the adjustment means 28 accordingly until the lower value has reached the upper value. As an alternative to this, the display device 38 may only show an arrow, for example, which indicates a rotation of the adjustment means 28 to the right or to the left as a command. As soon as the target position has been reached, a stop sign may be displayed, for example.

(40) Alternatively, however, the device can also fully automatically align the upper in relation to the lower changeable tool 2, 18, more specifically first the upper and then the lower changeable tool 2 and 18, respectively.

(41) To this end, not only sensor units 32-34 are provided, but also motor-driven adjustment means 28-30, e.g., stepper motors or servomotors. These motors are coupled to the control unit 37, as are the sensor units 32-34.

(42) Using the image information received from the cameras 50, 51, the control unit 37 drives the respective motors until an alignment has been completed. The instantaneous motor position is detected by means of the sensor units 32-34.

(43) After the changeable tools 2, 10, 18 have been aligned, the cameras 50, 51 are removed again, and the flat bed die-cutting press starts to operate.

(44) The cameras 50, 51, however, need not be provided only temporarily for alignment purposes; they may also be accommodated in the device permanently, either in the region of the holder 5 or at the retainer 60 that is fixed to the machine frame, as in indicated in FIG. 4. Here, the upper changeable tool 2 has an opening 61 in the stripping board 3, through which the camera 50, 51 can view the sheet 122 or the lower changeable tool 18. The opening 61 is, for example, positionally oriented in relation to the mark on the lower changeable tool 18 such that they are centered on each other. The camera 50, 51 furthermore captures, for example, the edge 62 of the opening 61, so that it also allows to detect the position of the upper changeable tool 2 by means of the edge 62. Then the circular contour of the edge 62 is reproduced on the screen, for example.

(45) If an additional tool, e.g. tool 10, is to be aligned, tool 18 might be aligned before tool 10 is introduced into the device. Tool 10 is also to be aligned by the cameras. Tool 18 might be provided with marks or might be provided with an opening like opening 61 so as to present an opening edge for sensing by the camera, positioning and aligning. The opening should, however, have an opening area which is smaller than the opening of the upper tool, i.e. changeable tool 3 allowing the camera 50 or 51 to sense both opening edges simultaneously.

(46) Rather than two cameras 50, 51, it is also possible to provide one camera, which then must have a larger angle of view in order to detect marks spaced apart from each other.

(47) Alternatively or additionally to the manual alignment, provision may also be made for a completely autonomous self-alignment. To this end, the control unit is configured to automatically align the holders on the basis of the data received from the at least one camera. The operator may possibly also make a decision by himself/herself as to whether the alignment is to be carried out manually or automatically. If the device effects the alignment only automatically, the display devices may possibly also be dispensed with.