EP4347148A1

EP4347148A1 - Drive device for a machine tool, machine tool, and method for operating a machine tool

Info

Publication number: EP4347148A1
Application number: EP21729252.3A
Authority: EP
Inventors: Antti ALA-PRINKKILÄ
Original assignee: Finn Power Oy
Current assignee: Finn Power Oy
Priority date: 2021-05-24
Filing date: 2021-05-24
Publication date: 2024-04-10
Also published as: WO2022248008A1

Abstract

The invention relates to a drive device (10) for a machine tool (100), for example, a punching machine tool, the machine tool (100) thereof, and a method for operating the machine tool (100). The drive device (10) comprises a wedge unit (20) adapted for translating movement provided by a drive unit (15) of the machine tool (100) in a first direction (X) to a movement of a ram connection portion (60)of the machine tool (100) in a second direction (Z), wherein the second direction (Z) differs from the first direction (X), wherein the wedge unit (20) defines a guide angle (21) determining a relation between a movement distance in the first direction (X) and a movement distance in the second direction (Z). Furthermore, the guide angle (21) is arranged to be adjustable.

Description

DRIVE DEVICE FOR A MACHINE TOOL, MACHINE TOOL, AND METHOD FOR OPERATING A MACHINE TOOL

Technical field

The present invention relates in general to machine tools, such as for sheet metal working. In particular, however not exclusively, the present invention concerns drive devices of the machine tools, for example, a punching machine tool.

Background

There are known sheet fabrication machines utilizing a contact mechanism, in the form of a roller being movable along the direction parallel to the plane of the worksheet. The roller is arranged to make a contact with the ram of the tool assembly for driving the tool in a direction that is essentially orthogonal to the direction in which the roller is driven, thereby converting a force in one direction to force for driving the tool in another direction.

The mechanism for converting the drive movement along one direction into a driving force in another direction can be provided by the interaction between a roller and a preconfigured mechanism, for example, a cam. Such mechanism works well so long as the work to be performed on a worksheet requires a particular force at a given speed. To change to a different force, either the roller or the cam of the force direction conversion mechanism has to be replaced. Needless to say, such replacement not only is time consuming but requires shutting down the machine during the mechanism exchange process.

In some known machine tools, there are two cams working cooperatively with a contact mechanism including a roller. The two cams are fixedly mounted to a carriage plate that is positioned over the tool mechanism. The carriage plate is movable, by means of either hydraulic or servo drives, to position one of the cams to interpose between the roller and the tool. Once positioned appropriately, by moving the roller in one direction, the cam, which has at least one surface that makes contact with the roller, converts the force supplied by the roller in said one direction into another direction. The two cams can have different angles of said surfaces that makes the contact and, thereby enable the user to select, from two choices, the desired cam with the appropriate speed and force for the punching. The two cams together with the mechanism for moving the carriage plate is, however, complex and heavy, and thus also adds mass to the drive device of the machine tool. Furthermore, if neither one of the two cams happens to be optimized for the work piece in question, that is, for particular force and speed, one or both of them needs to be replaced which is time consuming and requires shutting down the machine, or the machine is operated sub- optimally relative to demands related to the work piece in question.

Summary

An objective of the present invention is to provide a drive device for a machine tool, a machine tool, and a method for operating a machine tool. Another objective of the present invention is that the drive device, the machine tool, and the method provide convenient and more optimized operation with respect to various different work pieces, such as sheet metals with different material and/or thickness.

The objectives of the invention are reached by a drive device for a machine tool, a machine tool, and a method for operating a machine tool as defined by the respective independent claims.

According to a first aspect, a drive device for a machine tool, for example, a punching machine tool, is provided. The drive device comprises a wedge unit adapted for translating movement provided by a drive unit of the machine tool in a first direction, for example, X-direction, to a movement of a ram connection portion of the machine tool in a second direction, for example, Z-direction, wherein the second direction differs from the first direction. Furthermore, the wedge unit defines a guide angle determining a relation between a movement distance in the first direction and a movement distance in the second direction. Still further, the guide angle is arranged to be adjustable.

Furthermore, the guide angle may be configured to be adjusted between at least two angles. In some embodiments, the guide angle may be configured to be adjusted between at least three or five different angles. Alternatively or in addition, the guide angle may, preferably, be configured to be adjusted in a stepless manner.

In various embodiments, the wedge unit may comprise a guide surface defining the guide angle, wherein the guide surface is adapted to be in contact with and move relative to a wedge counterpart of the wedge unit during said movement translation. Optionally, the wedge unit may further comprise a wedge element defining the guide surface. In some embodiments, the wedge element may be further arranged, at its first position, to pivot relative to the drive device to enable the adjustment of the guide angle.

Furthermore, the drive device may comprise, as a part of an adjusting mechanism of the drive device, a gear arrangement for adjusting the guide angle. The gear arrangement may, optionally, be a worm gear arrangement. Still specifically, the gear arrangement may be a globoid or double-throated worm gear arrangement.

In various embodiments, the gear arrangement comprise a first gear and a second gear, wherein the first gear is coupled to or defined by the wedge element, and the second gear is arranged to be operated so as to adjust the guide angle.

In some other embodiments, the wedge element may be arranged eccentrically relative to a centre axis of the wedge element so that the guide angle is adjustable by rotating the wedge element around an eccentrical axis.

Furthermore, the drive device may, preferably, comprise a locking device for locking the guide angle to its position.

According to a second aspect, a machine tool, for example, a punching machine tool, is provided. The machine tool comprises at least one drive device of in accordance with the first aspect. Furthermore, the machine tool comprises a ram coupled to or integrated with the ram connection portion of the machine tool. Still further, the machine tool comprises a controllable actuator arranged to operate the drive device to adjust the guide angle.

The machine tool may, preferably, be configured to operate the controllable actuator, such as to adjust the guide angle, based on a characteristic related to a work piece and/or to a selected tool. This may mean adjusting, by the controllable actuator, the guide angle in order to optimize the force and speed provided by the drive device to work the work piece.

In some embodiments, the controllable actuator may be separate with respect to the drive device, and may, optionally, be configured to be temporarily coupled with the drive device for adjusting the guide angle. Thus, after the adjustment of the guide angle, the controllable actuator may be separated or decoupled from the drive device, thereby not adding mass during operation of the drive device.

According to a third aspect, a method for operating a machine tool, for example, a punching machine tool, in accordance with the second aspect is provided. The method comprises: determining a target value of the guide angle, such as based on a user input and/or based on a characteristic related to a work piece and/or to a selected tool, and operating the controllable actuator so as to adjust the guide angle to the determined target value.

In various embodiments, the machine tool may be configured to automatically determine the guide angle based on the characteristic related to the work piece and/or to the selected tool, for example, utilizing pre-defmed parameters for the characteristic(s). For example, the thickness and/or material of the work piece, and/or property of the selected tool (that is, such pieces of information alone or in combination) may be automatically utilized, based on pre-defmed parameters or logic, to determine the value of the guide angle in order to optimize the operation of the machine tool.

The present invention provides a drive device for a machine tool, a machine tool, and a method for operating a machine tool. The present invention provides advantages over known solutions in that the operation of the machine tool, especially related to drive device thereof, can be optimized to different work pieces quickly and conveniently.

Various other advantages will become clear to a skilled person based on the following detailed description. The expression "a plurality of’ may refer to any positive integer starting from two (2), that is being at least two.

The terms “first”, “second” and “third” are herein used to distinguish one element from other element, and not to specially prioritize or order them, if not otherwise explicitly stated.

The exemplary embodiments of the present invention presented herein are not to be interpreted to pose limitations to the applicability of the appended claims. The verb "to comprise" is used herein as an open limitation that does not exclude the existence of also unrecited features. The features recited in the claims are mutually freely combinable unless otherwise explicitly stated.

The novel features which are considered as characteristic of the present invention are set forth in particular in the appended claims. The present invention itself, however, both as to its construction and its method of operation, together with additional objectives and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

Brief description of the drawings

Some embodiments of the invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings.

Figures 1A and IB illustrate schematically a drive device according to an embodiment.

Figure 2 illustrates schematically a drive device according to an embodiment.

Figure 3 illustrates schematically a drive device according to an embodiment. Figures 4A and 4B illustrate schematically a drive device according to an embodiment.

Figure 5 illustrates schematically a machine tool according to an embodiment.

Figure 6 shows a flow diagram of a method according to an embodiment. Detailed description

Figures 1A and IB illustrate schematically a drive device 10 according to an embodiment. The drive device 10 may, preferably, be part of a machine tool, such as for sheet metal working. The drive device 10 of Figs. 1A and IB comprises a wedge unit 20 adapted for translating movement provided by a drive unit of the machine tool (not shown in Figs. 1A and IB) in a first direction X to a movement of a ram connection portion (not shown) of the machine tool in a second direction Z. The second direction Z differs from the first direction X, for example, by an angle therebetween in the range of 45 to 135 degrees, preferably in the range of 75 to 105, most preferably about 90 degrees as shown in Figs. 1 A and IB. The wedge unit 20 also defines a guide angle 21 determining a relation between a movement distance in the first direction X and a movement distance in the second direction Z. In Figs. 1 A and IB, the guide angle 21 is defined, as a non-limiting example, by the angle between the direction of the guide surface 24 and the first direction X, however, the guide angle 21 can alternatively be defined in some other way also. Furthermore, as visible in Figs. 1A and IB, the guide angle 21 is arranged to be adjustable, that is, the guide angle 21 can be changed or adjusted between at least two angles, namely the first angle 101 and the second angle 102, which relate to first and second positions of the wedge unit 20. In Fig. 1 A, the guide angle 21 is smaller than in Fig. IB. Optionally, the guide angle 21 may be configured to be adjusted between at least at least three or five different angles.

Notwithstanding the details presented in Figs. 1A and IB, or in any of the figures herein, in some embodiments the adjustable guide angle 21 may be arranged to be coupled to the ram connection portion of the wedge unit 20. Thus, the wedge element 22 may be coupled to the frame of the ram connection portion and/or the ram of the machine tool. The same effects are obtained even if locations of the fixed part and the adjustable part of the wedge unit 20 related to the translation of movement between the first X and the second directions Z are changed relative to each other.

As also visible in Figs. 1 A and IB, the guide surface 24 may comprise or define one or several portions. However, in various embodiments, the guide angle 21 may refer to one of those portions or some representative value of one or several of them, such as a tangent or an average angle value. Notwithstanding the exact way the guide angle 21 is defined in a particular embodiment, the important thing is that the angle 21 is adjustable.

In preferable embodiments, the guide angle 21 may be configured to be adjusted in a substantially stepless manner, such as between two extreme positions thereof, including or excluding (that is, either from about 0 or 1 degrees to about 90 to 89 degrees, respectively, as will be described hereinbelow for angles of the extreme positions of 0 and 90 degrees, for instance) the extreme positions.

Furthermore, in various embodiments, the wedge unit 20 may comprise a guide surface 24 defining the guide angle 21, wherein the guide surface 25 is adapted to be in contact with and move relative to a wedge counterpart (not shown in Figs. 1 A and IB) of the wedge unit 20 during said movement translation from the first direction X to the second direction Z.

Referring now back to the extreme positions, they may be, according to an example, the following:

- the direction of the guide surface 24 is parallel relative to the second direction Z, when consider embodiments in accordance with Figs. 1 A and IB, thereby the wedge unit 20 is not capable of translating the movement into the second direction Z (that is, the guide angle 21 being 90 degrees), and

- the direction of the guide surface 24 is perpendicular relative to the second direction Z when consider embodiments in accordance with Figs. 1A and IB, thereby the wedge unit 20 is not capable of translating the movement into the second direction Z (that is, the guide angle 21 being 0 degrees).

It is to be noted that the extreme positions may also be defined in some other ways. For example, in some cases the extreme position may be the maximum or minimum distance that the ram of the machine tool, such as due to the movement of the ram connection portion, can or must move so that it will not penetrate too deep or so that it will at least penetrate or punch until it becomes in contact (or a bit more) with the work piece, such as a sheet metal, respectively. Thus, the extreme positions may thus define a smaller range than the one described above with respect to Figs. 1 A and IB. The smaller range can be, for example, from about 5 degrees to about 25 or 35, or 45 degrees.

In accordance with the non-limiting example regarding defining the guide angle 21 as described above, with the smaller guide angle 21, the distance that the wedge element 22 moves relative to the wedge counterpart provides smaller movement of the ram connection portion than with would be provided the larger guide angle 21. The force generated is, on the other hand, higher with the smaller guide angle 21 but the operation is slower due to the longer movement distance required for moving the ram connection portion for the required amount. Thus, with the larger guide angle 21, the operation of the machine tool can be made faster due to shorter movement distance required. Thus, the operation of the machine tool comprising such drive device 10 can be optimized by selecting the best guide angle 21 for the work piece and/or selected tool in question. For example, for thinner sheet metals, and in many cases depending also of the particular metal material thereof, the guide angle 21 as defined above can be selected to be large since the required force is less than for thicker sheet metals.

In various embodiments, the wedge unit 20 may comprise a wedge element 22 defining the guide surface 24, wherein the wedge element 22 is arranged, at its first position 29, to pivot relative to the drive device 10 to enable the adjustment of the guide angle 21. In Figs. 1A and IB, an axis around which the wedge element 22 can pivot is arranged close to one end of the wedge element 22 which, in this case, has an elongated shape. Other positions for the pivot axis and/or shapes for the wedge element 22 are, of course, possible.

Still further, the drive device 10 may comprise a linear guide 12 or guiding means 12 for enabling the movement of the drive device 10 in the first direction X when the drive unit (not shown in Figs. 1 A and IB) is being operated.

Figure 2 illustrates schematically a drive device 10 according to an embodiment. The drive device 10 is in many ways similar to the one illustrated in Figs. 1 A and IB and described in connection thereto, however, Fig. 2 illustrates, as a part of an adjusting mechanism of the drive device 10, a gear arrangement 30 for adjusting the guide angle 21. The gear arrangement 30 may comprise a first gear 31 and a second gear 32 for translating the movement for adjusting the guide angle 21. The first gear 31 may, preferably, be coupled to or defined by the wedge element 22, and the second gear 32 may be arranged to be operated so as to adjust the guide angle 21.

In Fig. 2, the gear arrangement 30 is a worm gear arrangement, or specifically a type of worm gear, a globoid or double-throated worm gear arrangement. The globoid or double-throated worm gear is coupled to the frame of the drive device 10 on the left in Fig. 2 and is arranged to rotated by a controllable actuator. In Fig. 2, the wedge element 22, and particularly its other end with respect to the end comprising the pivot axis, defines the first gear 31 which is arranged to engage the globoid or double-throated worm gear, that is the second gear 32. Thus, the globoid or double- throated worm gear can be utilized to adjust the guide angle 21 and, at the same time, the globoid or double-throated worm gear provides support for the other end of the wedge element 22 during operation of the drive device 10 for translating the movement to drive the ram of the machine tool. The gear arrangement 30, and especially the globoid or double-throated worm gear arrangement, is especially advantageous since the wedge element 22 can be supported along the length of thread or teeth of the gears.

In some embodiments, the gear arrangement 30 may be such that the second gear 32 may not be rotatable, such as shown in Fig. 2. Alternatively, the second gear

32 may comprise teeth and it may be arranged to be disengaged relative to the teeth of the first gear 31, after which the position of the wedge element 22 is changed, such as by a controllable actuator, prior to engaging the teeth of the second gear 32 back with the teeth of the first gear 31. In that sense the gear arrangement does not operate in the same way as in Fig. 2, however, provides the same advantageous effects of supporting the wedge element 22 along the length of teeth of the gears 31, 32.

In various embodiments, the drive device 10 may also comprise a locking device 50 for locking the guide angle 21 to its position. This is shown in Fig. 2 to be on the leftmost part of the drive device 10, however, the details are not clearly visible. The locking device 50 may be any kind of arrangement for preventing the second gear 30 from rotating freely. The locking device 50 may, for example, comprise a pin or the like operated by an electronic actuator, for example, including an electromagnet or a solenoid. Furthermore, the drive device 10 may comprise a position sensor (not shown) for determining the position of the wedge unit 10, thereby enabling monitoring of the position also by the machine tool or the controlling unit thereof.

Figure 3 illustrates schematically a drive device 10 according to another embodiment. The drive device 10 is in some ways similar to the one illustrated in Figs. 1 A and IB and described in connection thereto, however, Fig. 3 illustrates, as a part of the adjusting mechanism of the drive device 10, a hydraulic system for adjusting the guide angle 21. As can be seen in Fig. 3, the other end of the wedge element 22 relative to the end of the wedge element 22 shown to comprise the pivot axis (at 29), comprises a hydraulic piston arranged to engage a hydraulic cylinder 35. The piston may be arranged to pivot with respect to the wedge element 22. As shown with the circle at the upper end of the hydraulic cylinder, the cylinder may also be arranged to pivot with respect to the frame of the drive device 10.

Furthermore, Fig. 3 shows a hydraulic system 40 in connection with the hydraulic cylinder. The hydraulic system 40 may be completely or partly part of the drive device 10, or may be completely separate with respect to the drive device 10, except for the connection therebetween which may be releasable or fixed. The hydraulic system 40 may comprise a hydraulic actuator for providing hydraulic medium, such as oil, into the hydraulic cylinder, thereby allowing adjusting the guide angle 21. There may also be a locking device 50, such as comprising a controllable valve, arranged to prevent the flow of hydraulic medium into and out of the cylinder.

In various embodiments, the wedge element 22 may be arranged to exhibit, on its outer surface, a plurality of different portions of guide surface 24, each portions having different value of guide angle 21. Furthermore, by arranging the wedge element 22 to be rotated around its rotating axis, which also acts to support the wedge element 22 during operation of the machine tool, so that different portion of the wedge element 22 is utilized depending on the position of the wedge element 22 with respect to the wedge counterpart.

Figures 4A and 4B illustrate schematically a drive device 10 according to yet another embodiment. In Figs. 4A and 4B, the wedge element 22 has a round cross- section (although it could also have basically any shape) and is arranged eccentrically relative to a centre axis of the wedge element 22 so that the guide angle 21 is adjustable by rotating, such by the controllable actuator via the adjusting mechanism of the drive device 10, the wedge element 22 around eccentrical axis 55 thereof, which also acts to support the wedge element 22 during operation of the machine tool. Thus, the wedge element 22 may have a symmetrical outer shape (round, for instance) since the element 22 is arranged to be rotated around the eccentrically arranged axis 55.

The movement distance of the wedge counterpart 61, which may be, for example, integrated into or coupled to the ram connection portion 60 or a surface thereon, is marked with reference number 59. It is the same in both Figs. 4A and 4B. Also shown in Figs. 4A and 4B is the distance along the surface of the wedge element 22 (that is, the guide surface 24 thereof) over which the wedge counterpart 61 is in contact with during said movement distance. These distance are marked with PI and P2 in Figs. 4A and 4B, respectively. As can be seen, the distance PI is longer than P2. Once again, the smaller guide angle 21 (first guide angle 101) requires longer distance, that is PI, in order to produce the same amount of movement of the ram connection portion, and thus the ram of the machine tool when compared to the larger guide angle 21 (second guide angle 102). The force generated is higher with the smaller guide angle 21 but the operation is slower due to the longer movement distance required for moving the ram connection portion for the required amount, as explained hereinbefore with respect to Figs. 1 A and IB.

In alternate embodiments, the distance of the wedge element 22, such as the one illustrated in Figs. 4A and 4B, relative to the wedge counterpart and/or the ram connection portion can be changed in other way than with the eccentrically arranged axis 55 in order to obtain the same effect. For example, the wedge element 22 may be arranged to be moved in the second direction by a linear guide. Thus, the similar effect is obtained than with the rotation around the eccentrically arranged axis 55.

Figure 5 illustrates schematically a machine tool 100 according to an embodiment. As can be seen, the machine tool 100 comprises a drive device 10 as described hereinbefore. Furthermore, the machine tool 100 comprises a ram 70 coupled to the ram connection portion 60 of machine tool 100. In various embodiments, such as the one in Fig. 5, the ram connection portion 60 is a roll or roller. Still further, the machine tool 100 comprises a controllable actuator 45 arranged to operate, such as via the adjusting mechanism (details not shown, however, located on the leftmost part of the drive device 10 in Fig. 5), the drive device 10 to adjust the guide angle 21. The controllable actuator 45 may be directly mounted to or can be arranged couplable/decouplable with respect to the drive device 10.

Thus, in various embodiments, the controllable actuator 45 may be separate with respect to the drive device 10, and may be further configured to be temporarily coupled with the drive device 10 for adjusting the guide angle 21, and then subsequently once again decoupled therefrom. Thus, the controllable actuator 45 does not add mass to the drive device 10 which is very advantageous.

Regarding the operation of the machine tool 100, Fig. 5 shows a controlling unit 1000 of the machine tool 100. The controlling unit 1000, such as comprising at least a processing unit or a processor, and memory for storing data and/or program instructions to be executed by the processing unit in order to operate the machine tool 100. The controlling unit 1000 may arranged in connection, and also to control the operation of, at least the controllable actuator 45 and the drive unit 15 of the machine tool 100. The drive unit 15 may comprise at least a motor 19 of the machine tool 100 and, for example, a ball screw 17 connected thereto for providing movement of the drive device 10 in the first direction X. The motor 19 may be a servo motor. A skilled person in the art knows that the movement of the drive device 10 in the first direction X may also be provided in other ways, such by utilizing hydraulic and/or gears etc. Figure 5 also shows the cylinder 67 of the ram 70. Fig. 5 also shows a work piece 99 arranged below the ram 70. In this case, the work piece 99 is sheet metal. The drive device 10 may further comprise a backstop 65, such as arranged on the opposite side of the linear guide 12 with respect to the wedge unit 20.

Figure 6 shows a flow diagram of a method according to an embodiment. Item 600, which may not be a part of the method per se, may refer to a start-up phase of the method. Suitable equipment and components are obtained and systems assembled and configured for operation.

Item 610 refers to determining a target value of the guide angle 21. The target value may be determined, for example, by the controlling unit 1000 of the machine tool 100. In various embodiments, the determination of the target value may be based on, for example, a user input, such as on a manually inputted information representing thickness and/or material of the work piece 99, such as sheet metal, or the desired speed of the machine tool. Alternatively or in addition, the determination of the target value may be based on a characteristic related to a work piece 99, in which case the characteristic may be determined (automatically or based on an input command by the user) by the machine tool, such as by a sensor thereof. Further alternatively or in addition, the determination of the target value may be based on a selected tool of the machine tool. The user may have, for example, selected a certain punching tool, the information regarding which may be utilized partly or wholly to determine the optimal or as good as possible, or good enough value for the guide angle 21.

Item 615 refers to an optional feature performed only in some embodiments and, thus, marked with a dashed line. Item 615 refers to coupling the controllable actuator 45 with the drive device 10 in order to adjust the guide angle 21. Thus, in these embodiments, the controllable actuator 45 is separate and can also be functionally coupled and decoupled with respect to the drive device 10.

In various embodiments, the coupling may be performed by, for example, moving, such as lowering, the controllable actuator 45 towards the drive device 10 so that an engaging member of the actuator 45 engages with a counterpart mounted on the drive device 10, such being part of the adjusting mechanism of the drive device 10. This may, preferable, be performed automatically by an actuating system (not shown in the figures herein) of the machine tool 100. The controllable actuator 45 may thus be similar to a drill or screw gun, however, it may alternatively be something different, as long as it is able to provide force to adjust the guide angle, such as via the adjusting mechanism. In various embodiments, the controllable actuator 45 may be arranged to rotate the counterpart which is further coupled, at least functionally, with, for example, the adjusting mechanism of the drive device 10 to adjust the guide angle 21.

Item 620 refers to operating the controllable actuator 45, such as by the controlling unit 1000, so as to adjust the guide angle 21 to the determined target value, such via the adjusting mechanism of the drive device 10. As described hereinabove, the adjusting may include rotating the counterpart of the adjusting mechanism or changing the level of hydraulic medium in the hydraulic cylinder or the like for changing the guide angle 21.

Item 625 refers to an optional feature performed only in some embodiments and, thus, marked with a dashed line. Item 615 refers to decoupling the controllable actuator 45 from the drive device 10. Thus, in these embodiments, the controllable actuator 45 is separate and can also be functionally coupled and decoupled with respect to the drive device 10. This provide the effect that, during driving of the drive device 10 to work on the work piece 99, the decoupled controllable actuator 45 does not add mass to the drive device 10.

In various embodiments, the decoupling may be performed by, for example, moving, such as raising, the controllable actuator 45 away from the drive device 10 so that the engaging member of the actuator 45 disengages with the counterpart mounted on the drive device 10, such being part of the adjusting mechanism of the drive device 10. This may, preferable, be performed automatically by the actuating system (not shown in the figures herein) of the machine tool 100.

Furthermore, the adjusting of the guide angle 21 may, in various embodiments, be configured to be performed during a tool changing process, especially in case of a machine tool comprising automatic tool changing device or means. Alternatively or in addition, the adjusting of the guide angle 21 may, in various embodiments, be configured to be performed during any other pause in the machine tool operation, such as during changing of the work piece 99 or when moving the tool to another portion of the work piece 99. In some cases, the operation of the machine tool 100 may be paused just for the sake of adjusting the guide angle 21.

Method execution is stopped at step 699. This may mean that the machine tool 100 is now ready for working on the work piece 99, such as punching through or at least partly penetrating the work piece 99 by the selected tool mounted to the ram 70.

Claims

Claims:

1. A drive device (10) for a machine tool (100), wherein the drive device (10) comprises: a wedge unit (20) adapted for translating movement provided by a drive unit (15) of the machine tool (100) in a first direction (X) to a movement of a ram connection portion (60) of the machine tool (100) in a second direction (Z), wherein the second direction (Z) differs from the first direction (X), wherein the wedge unit (20) defines a guide angle (21) determining a relation between a movement distance in the first direction (X) and a movement distance in the second direction (Z), characterized in that the guide angle (21) is arranged to be adjustable.

2. The drive device (10) of claim 1, wherein the guide angle (21) is configured to be adjusted between at least two angles (101, 102) or, optionally, between at least at least three or five different angles.

3. The drive device (10) of any one of claims 1-2, wherein the guide angle (21) is configured to be adjusted in a stepless manner.

4. The drive device (10) of any one of claims 1-3, wherein the wedge unit (20) comprises a guide surface (24) defining the guide angle (21), wherein the guide surface (25) is adapted to be in contact with and move relative to a wedge counterpart (61) of the wedge unit (20) during said movement translation.

5. The drive device (10) of claim 4, wherein the wedge unit (20) comprises a wedge element (22) defining the guide surface (24), wherein the wedge element (22) is arranged, at its first position (29), to pivot relative to the drive device (10) to enable the adjustment of the guide angle (21).

6. The drive device (10) of any one of claims 1-5, comprising a gear arrangement (30) for adjusting the guide angle (21).

7. The drive device (10) of claim 6, wherein the gear arrangement (30) is a worm gear arrangement

8. The drive device (10) of claim 7, wherein the gear arrangement (30) is a globoid or double-throated worm gear arrangement.

9. The drive device (10) of claim 5, wherein the wedge element (22) is arranged eccentrically relative to a centre axis of the wedge element (22) so that the guide angle (21) is adjustable by rotating the wedge element (22) around an eccentrical axis (55).

10. The drive device (10) of any one of claims 6-8, wherein the gear arrangement (30) comprise a first gear (31) and a second gear (32), wherein the first gear (31) is coupled to or defined by the wedge element (22), and the second gear (32) is arranged to be operated so as to adjust the guide angle (21).

11. The drive device (10) of any one of claims 1-10, comprising a locking device (50) for locking the guide angle (21) to its position.

12. A machine tool (100), characterized in that it comprises: a drive device (10) of any one of claims 1-11, a ram (70) coupled to the ram connection portion (60), and a controllable actuator (45) arranged to operate the drive device (10) to adjust the guide angle (21).

13. The machine tool (100) of claim 12, configured to operate the controllable actuator (45) based on a characteristic related to a work piece (99) and/or to a selected tool.

14. The machine tool (100) of claim 12 or 13, wherein the controllable actuator (45) is separate with respect to the drive device (10), and is configured to be temporarily coupled with the drive device (10) for adjusting the guide angle (21).

15. A method for operating a machine tool (100) in accordance with any one of claims 12-14, characterized in that the method comprises: determining (610) a target value of the guide angle (21), such as based on a user input and/or a characteristic related to a work piece (99) and/or to a selected tool, and operating (620) the controllable actuator (45) so as to adjust the guide angle (21) to the determined target value.