DE20020500U1 - Tool for slitting plate-like workpieces - Google Patents

Description

TELEPHONE: 0711/784731 jTBLE^A«: ·0 7 1·1/*7 | 0 || 9 ^/9 6 KÖHLER SCHMID + P .RU P PMAIW STE*. 2T·O'-70 5δ^ STUTTGART

KÖHLER SCHMID + PARTNER

PATENT ATTORNEYS

24 298 Sl/te

Trumpf GmbH + Co.
Johann-Maus-Strasse 2 71254 Ditzingen

Tool for slotting plate-type workpieces

The invention relates to a tool for slitting plate-like workpieces, in particular sheet metal, with two tool parts which are opposite one another in the transverse direction of the workpiece and are movable relative to one another in a stroke direction transverse to the workpiece with a working stroke, comprising a slitting stroke and a cutting stroke in extension of the slitting stroke, and each of which has at least two slitting cutting edges running in the slitting direction and spaced apart from one another transversely thereto and transversely to the stroke direction, as well as at least one between the slitting cutting edges transversely to the slitting direction

and a cutting edge running transversely to the stroke direction and spaced from the longitudinal ends of the slot cutting edges, wherein the slot cutting edges of the tool parts are movable relative to one another during the slotting stroke to create a workpiece strip and the cutting edges of the tool parts are movable relative to one another during the cutting stroke to cut the workpiece strip, and wherein the slot cutting edges of one tool part are divided at the level of the cutting edge on the other tool part and at least one front cutting edge carrier with the front part of the slot cutting edges in the slot direction and at least one rear cutting edge carrier with the rear part of the slot cutting edges in the slot direction are provided, and wherein the rear cutting edge carrier has a cutting edge assigned to the cutting edge on the other tool part and the rear and front cutting edges carriers are movable relative to one another in the stroke direction during the cutting stroke.

When slitting, a strip of the workpiece is cut free, which lengthens as the workpiece processing progresses. If the slit created is long enough, the strip of the workpiece cut free would have a length that could hinder the machining process. For this reason, the workpiece strip is cut from time to time during the machining process. For this purpose, the following are currently being proposed:

Slotting tools as initially described and as disclosed in JP 61-154721 A.

The previously known tool consists of two tool parts in the form of an upper and a lower tool. The upper tool comprises two cutting edge carriers of the type described above, which are adjacent to one another in the direction of the slot. The cutting edge carrier at the rear in the direction of the slot is firmly connected to a ram of the machine tool in question and forms a cutting edge running transversely to the direction of the slot on its side facing the cutting edge carrier at the front in the direction of the slot. The cutting edge carrier at the front in the direction of the slot is guided on the ram so that it can be moved in the stroke direction of the tool. Against the action of a return spring, the front cutting edge carrier can be moved from an initial position in which the slot cutting parts provided on it run as an extension of the slot cutting parts on the rear cutting edge carrier, to a position in which its slot cutting parts are offset in the stroke direction relative to the slot cutting parts on the rear cutting edge carrier, thereby releasing the cutting edge on the rear cutting edge carrier. A cutting edge on the lower tool is assigned to the cutting edge on the rear cutting edge carrier of the upper tool. This cutting edge is formed on the edge of a step inside a recess on the lower tool. The longitudinal edges of this recess run

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in the slot direction and serve as cutting edges of the lower tool. The cutting edge on the lower tool is set back from its slot cutting edges in the stroke direction.

When the previously known tool is operated, the lower tool supports the workpiece to be machined with the area surrounding its recess. The front and rear cutting edges on the upper tool are moved together in the stroke direction by lowering the ram that holds them and plunge into the recess on the lower tool. By means of the slotted cutting edges on the front and rear cutting edges of the upper tool and the slotted cutting edges on the lower tool that interact with them, a workpiece strip is first created during a slotted stroke, which merges into the unslotted workpiece at its front end in the slotting direction. As the ram continues to lower, the rear cutting edge of the upper tool penetrates deeper into the recess on the lower tool, while the front cutting edge of the upper tool - acted upon by the return spring - is supported on the step inside the recess of the lower tool. As a result of the resulting relative movement of the front and rear cutter holders, the cutting edge on the rear cutter holder is released and can now, in conjunction with the cutting edge of the lower tool, cut the previously created workpiece strip at a distance from its transition into the unmachined workpiece as part of a cutting stroke.

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During the slotting stroke, the return spring acting on the front cutting edge carrier of the upper tool is intended to prevent a relative movement of the front and rear cutting edges in the stroke direction and thereby ensure that the slotting cutting parts on the front and the slotting cutting parts on the rear cutting edge carrier are aligned with one another without any offset when slotting the workpiece to be machined. To fulfil this function, the return spring must be designed to be as hard as possible. The described offset-free course of the slotting cutting parts on the front and rear cutting edges is necessary in the interest of a smooth, marking-free formation of the cutting surfaces on the longitudinal edges of the slot created that run in the slotting direction.

During the cutting stroke, the return spring acting on the front cutter holder of the upper tool should allow the relative movement of the front and rear cutter holders required to cut the previously created workpiece strip while exerting as little counterforce as possible. This goal can best be achieved with a return spring that is as soft as possible.

All in all, in the case of the state of the art, two essentially opposing objectives must be pursued when designing the spring acting on the front cutting edge carrier of the upper tool. Designed accordingly difficult

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The design of the return spring is different and the risk of malfunctions of the previously known tool is correspondingly high, resulting in uneven cutting surfaces with markings on the longitudinal edges of the workpiece slots created.

The aim of the present invention is to remedy this situation.

According to the invention, this object is achieved by a tool of the type mentioned at the outset, on which the characterizing features of claim 1 are provided. The locking device according to the claim ensures in a functionally reliable manner that the cutting edge carriers on one part of the tool form a unit with offset-free cutting edges during the slotting stroke and are nevertheless movable relative to one another in the required manner during the cutting stroke following the slotting stroke. Accordingly, the tool according to the invention allows the reliable creation of smooth, marking-free cutting surfaces that are therefore suitable as visible surfaces on the longitudinal edges of the workpiece slots that run in the direction of the slot and at the same time - in the interest of a trouble-free processing sequence - a functional cutting of the workpiece strip created when slotting the workpiece in question. The cutting edges formed by the cutting edge carriers during the cutting stroke, i.e. when the locking device is switched to the unlocking position, are

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Locking device, relative movement to be carried out· as such can be realized with little effort.

Preferred embodiments of the tool according to the invention result from the dependent claims 2 to 8.

In the case of the inventive design according to claim 2, the relative position of the control element according to the claim and the tool part provided with the cutter holders and thus a clearly defined control basis is expediently used to control the locking device of the cutter holders. In a preferred embodiment of the invention, for the sake of simplicity, the workpiece to be machined itself is provided as a stop for the control element (claim 3).

The characterizing features of claims 4 to 6 primarily serve to provide a structurally simple design for tools according to the invention. There are a variety of options for the design of the locking member according to the invention as well as for its control. For example, a locking member or a locking lever can be used which can be switched electromagnetically into its locking and/or release position. The preferred mechanical solution according to claim 6 is characterized in particular by its great robustness.

EN 200 2ObUUU.

With the tool according to the invention, workpieces can be provided with slots that open into the edge of the workpiece as well as with slots that end in the workpiece interior. The inventive designs described in claims 7 and 8 are intended for the latter application. The relative rotation of the interacting tool parts according to the claim precedes the last working stroke. In the case of the tool according to claim 8, rotation of the tool part supporting the workpiece to be machined and the material stress that would otherwise be associated with this, for example scratching of the workpiece, are avoided.

The invention is explained in more detail below using schematic representations of an embodiment. They show:

Fig. 1 is a perspective view of a machine tool with a tool for slitting sheet metal installed at a machining station of the machine,

Fign. Individual sectional views of the machining station 2 to 6 of the machine tool according to Fig. 1

built-in tool in different phases of the

Sheet metal processing.

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As shown in Fig. 1, a machine tool 1 has, in a known manner, a substantially C-shaped machine frame 2. The latter has an upper frame leg 3 and a lower frame leg 4.

At the free end of the upper frame leg 3 there is a processing station 5 with a ram 7 that can be hydraulically raised and lowered in a stroke direction indicated by a double arrow 6. This has a tool holder 8 at its lower end, in which a tool part in the form of an upper tool 9 of a tool 10 for slitting sheet metal is installed. The ram 7 with the upper tool 9 can be rotated in a controlled manner in the direction of a double arrow 11 about a tool rotation axis 12 running in the stroke direction 6. In Fig. 1 a front cutting carrier 13 and a rear cutting carrier 14 of the upper tool 9 can be seen, which form slitting cutting edges 15, 16.

A lower tool 17, which is integrated into a workpiece table 18 on the lower frame leg 4, is assigned to the upper tool 9 on the ram 7 as a further tool part. The lower tool 17 has a slot opening 19, which in turn is delimited by longitudinal edges forming slot cutting edges 20, 21.

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As usual, a coordinate guide 22 is mounted on the lower frame leg 4 next to the workpiece table 18. By means of the coordinate guide 22, workpieces to be machined, in the example shown a sheet metal 23, can be moved in a known manner relative to the processing station 5 in a horizontal plane defined by coordinate axes x, y. In addition, the coordinate guide 22 is used - as is also known - for holding and for changing tools at the processing station 5. Like the other functions of the machine tool 1, the movement of the coordinate guide 22 is also controlled by a computer control 24 indicated in Fig. 1.

The structural design of the tool 10 can be seen in detail in Figs. 2 to 6.

Accordingly, the upper tool 9 of the tool 10 has a base body 26 to which the rear cutter carrier 14 is firmly connected and which supports the front cutter carrier 13 of the upper tool 9 so that it can move in the stroke direction 6. A connection between the front cutter carrier 13 and the base body 26 of the upper tool 9 is made by means of a toggle lever 27, one lever 28 of which is hinged to the outside of the base body 26 and the other lever 29 of which is hinged to the outside of the front cutter carrier 13. A knee joint 30 of the knee lever

-libels 27 is arranged inside a joint sleeve 31 which is rotatable relative to the knee joint 30.

The toggle lever 27 is part of a locking device 32 of the cutter holders 13, 14, which comprises a locking lever 33 pivotably mounted on the base body 26 of the upper tool 9 as a further locking element. A control slide 34 is used to control the pivoting position of the locking lever 33 and thus to control the switching position of the locking device 32. This control slide 34 is guided on the base body 26 of the upper tool 9 so that it can be moved in the stroke direction and is acted upon by a return spring 35 supported on one side on the base body 26. The end of the control slide 34 on the workpiece side is formed by a button 36.

Parts of the slot cutting edges 15, 16 of the upper tool 9 are provided on the front cutting edge carrier 13 and the rear cutting edge carrier 14. In addition, the rear cutting edge carrier 14 forms a cutting edge 41 at its rear end that runs transversely to the slot cutting edges 15, 16. The front surface of the rear cutting edge carrier 14 facing the front cutting edge carrier 13 is provided with a cutting edge 37 on its workpiece-side edge. At the start of the machining process, the slot cutting edges 15, 16 on the upper tool 9 run without offset and with an increasing distance from the sheet metal 23 to be machined in a slot direction 40.

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The parting line between the front cutter carrier 13 and the rear cutter carrier 14 and thus also the parting line between the parts of the slotted cutting edges 15, 16 provided on the cutter carriers 13, 14 is at the level of a cutting edge 38 which is formed on a cutting block 39 inside the slot opening of the lower tool 17. The cutting edge 38 is set back from the slotted cutting edges 20, 21 on the lower tool 17 in the stroke direction 6.

Fig. 1 shows the machine tool 1 after creating a slot 25 in the sheet metal 23. The processes preceding this operating state are essentially shown in Figs. 2 to 6.

First, the still unprocessed sheet 23 was moved by means of the coordinate guide 22 into its processing starting position opposite the processing station 5 of the machine tool 1. At this point in time, the tool 10 for slitting the sheet 23 was already installed at the processing station 5. The upper tool 9 was spaced from the sheet 23 in the stroke direction 6.

The upper tool 9 of the tool 10 was then moved in the stroke direction 6 while lowering the ram 7 to the sheet 2 3 supported in the direction of gravity by the workpiece table 18 and the lower tool 17. The locking device 32 inside

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of the upper tool 9 was initially in its locking position. The locking lever 33 - acted upon by the return spring 35 via the control slide 34 - assumed its horizontal pivoting position in which it supported the knee joint 30 of the knee lever 27 against deflection. The slotting cutting edges 15, 16 of the upper tool 9 ran without offset and with an increasing distance from the surface of the sheet 23 in the slotting direction 40. In this state, the upper tool 9 initially ran onto the surface of the sheet 23 with the cutting edge 41 on the rear cutting edge carrier 14 during the working stroke it carried out (Fig. 2).

As the working stroke continued, the upper tool 9 then plunged into the slot opening 19 of the lower tool 17. The cutting edge 41 and the cutting edges 15, 16 on the cutting edge carriers 13, 14 of the upper tool 9, which form a unit due to their locking, interacted with the cutting edge 42 and the slot cutting edges 20, 21 on the lower tool 17. In a phase of the working stroke referred to as the "slot stroke", a workpiece strip in the form of a sheet metal strip 43 was cut free on three sides. Due to the height offset of the cutting block 3 9 or the cutting edge 38 provided on it compared to the slot cutting edges 20, 21 of the lower tool 17, the sheet metal strip 4 3 extended in the slot direction 40 beyond the cutting edge 38 of the lower tool 17.

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During the initial working stroke of the tool 10, the control slide 34 had initially moved synchronously with the upper tool 9 in the stroke direction 6. During the slotting stroke, the control slide 34 then hit the top of an unprocessed area of the sheet 23 with the probe 36. During the remainder of the slotting stroke, the control slide 34 had then moved upwards relative to the upper tool 9 in the stroke direction 6. However, the relative movement carried out by the control slide 34 with respect to the upper tool 9 until the end of the slotting stroke had not yet led to a change in the pivoting position of the locking lever 33 inside the upper tool 9. The reason for this was the movement play existing in the stroke direction 6 between the control slide 34 and the locking lever 33. Accordingly, the front cutter carrier 13 and the rear cutter carrier 14 of the upper tool 9 were connected to form a rigid unit with offset-free slotting cutters 15, 16 via the locking device 32 until the slotting stroke was completed. Overall, the conditions shown in Fig. 3 resulted immediately before the end of the first slotting stroke carried out by the tool 10.

Due to the continuation of the working stroke carried out by the tool 10 or the upper tool 9, the control slide 34 then moved further upwards in the stroke direction 6 relative to the upper tool 9 against the effect of the return spring 35. In the process, the control slide 34 initially assumed its locking position.

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position of the locking lever 33. The knee joint 30 of the knee lever 27 was free to deflect as a result of the change in position of the locking lever 33 caused by the control slide 34 and could move to the left starting from its position according to Fig. 3. The joint sleeve 31 of the knee joint 30 rolled with little friction on the partially rounded end of the locking lever 33 facing it.

At the same time, the front cutter carrier 13 was supported by the cutting block 39 in the direction of the working stroke of the upper tool 9 via the sheet metal strip 43 and was thus blocked from moving further in the working stroke direction. By switching the locking lever 33 to the release position, i.e. by switching the locking device 32 to the unlocking position, the front cutter carrier 13 was enabled to move in the stroke direction β relative to the base body 26 of the upper tool 9 and thus relative to the rear cutter carrier 14. The rear cutter carrier 14 therefore penetrated deeper into the slot opening 19 on the lower tool 17 when the front cutter carrier 13 was supported on the cutting block 39. The cutting edge 37 on the rear cutter carrier 14 was thereby released and could, in conjunction with the cutting edge 38 on the cutting block 39, cut the previously produced sheet metal strip 43. The operating situation at the end of the cutting stroke, ie at the end of that phase of the working stroke of the

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Tool 10, in which the previously created sheet metal strip was severed, is illustrated in Fig. 4.

Fig. 4 shows the upper tool 9 in its lower end position. Starting from this position, the upper tool 9 was raised in the stroke direction 6 opposite to the direction of the previously executed working stroke. Under the action of the return spring 35, the control slide 34 initially moved relative to the upper tool 9. This was accompanied by a return of the locking lever 33 from its release position according to Fig. 4 to its locking position according to Figs. 2 and 3 and thus a transfer of the locking device 32 into the locking position.

After the upper tool 9 was raised so far that the cutting edge 41 of the rear cutting edge carrier 14 was positioned a short distance above the sheet 23, the sheet 23 was moved relative to the processing station 5 and thus relative to the tool 10 in the direction of the x-axis using the coordinate guide 22 of the machine tool 1. As a result, the sheet 23 came to lie between the upper tool 9 and the lower tool 17 of the tool 10 with an area extending in the extension of the slot created during the initial working stroke. Further working strokes of the tool 10 then followed with the processes described in detail above.

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Before the last working stroke, i.e. before the working stroke for cutting free the transverse boundary of the slot 25 located in the cutting direction 40, the upper tool 9 in its upper end position was rotated by 180° about the tool rotation axis by means of a corresponding drive with the ram 7 integrated in the upper frame leg 3 of the machine frame 2. The rotated upper tool 9 was then moved to the lower tool 17 by moving the ram 7 in the stroke direction 6. The upper tool 9 initially came to rest on the upper side of the sheet 23 with the cutting edge 41 of the rear cutter carrier 14 (Fig. 5). Due to the inclination of the slot cutting edges 15, 16 of the upper tool 9 and due to the recessed arrangement of the cutting block 3 9 and its distance from the boundary of the lower tool 17 in the slot direction, the upper tool 9 was then able to penetrate so far into the slot opening 19 of the lower tool 17 during the continued working stroke that the slot 25 in the sheet 23 was completely cut free, starting from its transverse boundary in the slot direction 4 0. During this last working stroke of the tool 10, the slot cutting edges 15 of the upper tool 9 interacted with the slot cutting edges 20, 21 of the lower tool 17 and the starting cutting edge 41 of the upper tool 9 interacted with the end cutting edge 44 of the lower tool 17 (Fig. 6).

After completion of the slot 25, the upper tool 9 was then raised again to a position above the sheet 23 and finally rotated about the tool rotation axis 12 to its original position. The sheet 23 itself was moved by means of the coordinate guide 22 in the direction of the y-axis to its position shown in Fig. 1.

Claims (8)

1. Tool for slitting plate-like workpieces, in particular metal sheets ( 23 ), with two tool parts ( 9 , 17 ) which are opposite one another in the transverse direction of the workpiece ( 23 ) and are movable relative to one another in a stroke direction ( 6 ) transverse to the workpiece ( 23 ) with a working stroke comprising a slitting stroke and a cutting stroke in extension of the slitting stroke, and each of which has at least two slitting cutting edges ( 15 , 16 ; 20 , 21 ) running in the slitting direction ( 40 ) and spaced apart from one another transversely thereto and transversely to the stroke direction ( 6 ), and at least one slitting cutting edge ( 15 , 16 ; 20 , 21 ) running transversely to the slitting direction ( 40 ) and transversely to the stroke direction ( 6 ) and extending from the longitudinal ends of the slitting cutting edges ( 15 , 16 ; 20 , 21 ) spaced cutting edge ( 37 , 38 ), wherein the slotted cutting edges ( 15 , 16 ; 20 , 21 ) of the tool parts ( 9 , 17 ) are movable relative to one another during the slotting stroke while creating a workpiece strip ( 43 ) and the cutting edges ( 37 , 38 ) of the tool parts ( 9 , 17 ) are movable relative to one another during the cutting stroke while cutting the workpiece strip ( 43 ), and wherein the slotted cutting edges ( 15 , 16 ) of one tool part ( 9 ) are divided at the level of the cutting edge ( 38 ) on the other tool part ( 17 ), and at least one front cutting edge carrier ( 13 ) is connected to the front part of the slotted cutting edges (15, 16) in the slotting direction (40) and at least one rear cutting edge carrier (14) is connected to the front part of the slotted cutting edges ( 15 , 16 ) in the slotting direction (40) and at least one rear cutting edge carrier ( 14 ) is connected to the front part of the slotted cutting edges (15, 16) in the slotting direction ( 40 ). 40 ) rear part of the slitting blades ( 15 , 16 ) are provided and wherein the rear blade carrier ( 14 ) has a cutting blade ( 37 ) associated with the cutting blade ( 38 ) on the other tool part ( 17 ) and the rear ( 14 ) and the front blade carrier ( 13 ) are movable relative to one another in the stroke direction ( 6 ) during the cutting stroke, characterized in that the blade carriers ( 13 , 14 ) are provided with a locking device ( 32 ) which can be switched in a controlled manner into a locking or an unlocking position, wherein the blade carriers ( 13 , 14 ) are connected to one another during the slitting stroke by means of the locking device ( 32 ) switched into the locking position and wherein the rear ( 14 ) and the front blade carrier ( 13 ) are movable when the locking device (32) is switched into the unlocking position. 32 ) are movable relative to each other in the stroke direction ( 6 ) during the cutting stroke. 2. Tool according to claim 1, characterized in that at least one control member is provided which is connected in a controlling manner to the locking device ( 32 ) of the cutting carriers ( 13 , 14 ) on the one tool part ( 9 ) and which, during the working stroke, is initially stationary relative to this tool part ( 9 ) in the stroke direction ( 6 ) and can be placed against a stop and which can then be moved against the stop relative to the tool part ( 9 ) in the stroke direction ( 6 ) into a position which is assigned to the start of the cutting stroke and when assumed, the control member controls the locking device ( 32 ) in the sense of a transfer from the locking to the unlocking position. 3. Tool according to one of the preceding claims, characterized in that a region of the workpiece ( 23 ) lying outside the workpiece strip ( 43 ) created during the slotting stroke is provided as a stop for the control member. 4. Tool according to one of the preceding claims, characterized in that the cutting carriers ( 13 , 14 ) are provided on a base body ( 26 ) of the relevant tool part ( 9 ), the rear cutting carrier ( 14 ) being firmly connected to the base body ( 26 ) and the front cutting carrier ( 13 ) being guided on the base body ( 26 ) so as to be movable in the stroke direction ( 6 ), and in that the locking device ( 32 ) of the cutting carriers ( 13 , 14 ) has at least one locking member supported on the base body ( 26 ), which can be switched in a controlled manner into a locking or a release position and which locks the front ( 13 ) and the rear cutting carrier ( 14 ) in the locking position against relative movement in the stroke direction ( 6 ) and releases them in the release position for relative movement in the stroke direction ( 6 ). 5. Tool according to one of the preceding claims, characterized in that the front cutter carrier ( 13 ) is connected to the base body ( 26 ) of the relevant tool part ( 9 ) via a toggle lever ( 27 ), one lever ( 28 ) of which is articulated on the outside to the base body ( 26 ) and the other lever ( 29 ) of which is articulated on the outside to the front cutter carrier ( 13 ), the connecting line of the outer joints of the toggle lever ( 27 ) running in the stroke direction ( 6 ) and that a locking lever ( 33 ) pivotably mounted on the base body ( 26 ) is provided as a locking member, which can be pivoted in a controlled manner into a locking or a release position and which supports the knee joint ( 30 ) of the toggle lever ( 27 ) in the locking position against deflection and releases it for deflection in the release position. 6. Tool according to one of the preceding claims, characterized in that the locking lever ( 33 ) of the locking device ( 32 ) of the cutter holders ( 13 , 14 ) can be pivoted from the locking position into the release position by means of a control member in the form of a control slide ( 34 ), wherein the control slide ( 34 ) during the working stroke is initially fixed in position relative to the tool part ( 9 ) having the locking device ( 32 ) in the stroke direction ( 6 ) and can be placed against a stop, preferably on an area of the workpiece ( 23 ) lying outside the created workpiece strip ( 43 ), and which can then be moved from the locking position into the release position in the stroke direction ( 6 ) relative to the tool part ( 9 ), resting against the stop, optionally on the said area of the workpiece ( 23 ), while taking the locking lever ( 33 ) with it. 7. Tool according to one of the preceding claims, characterized in that one ( 9 ) of the tool parts ( 9117 ) can be rotated by 180° about a tool rotation axis ( 12 ) running in the stroke direction ( 6 ) relative to the other tool part ( 17 ) while reversing the slot direction ( 40 ). 8. Tool according to one of the preceding claims, wherein one of the tool parts ( 9 , 17 ) is provided as an upper tool ( 9 ) and the other of the tool parts ( 9 , 17 ) is provided as a lower tool ( 17 ) supporting the workpiece ( 23 ), characterized in that the upper tool ( 9 ) is rotatable relative to the lower tool ( 17 ) by 180° about the tool rotation axis ( 12 ).