Press drive unit

Abstract

A drive unit for a press device includes a housing, a drive section disposed within the housing, a piston movable by the drive section from a stop position to a press position to transmit force from the drive section to a press tool connectable to the drive unit, and a connection element connected to the housing and having a receiving section for connection to the press tool, the connection element being lockable in at least a first position and a second position, and the distance between the stop position of the piston and the receiving section being different between the first position and the second position.

Description

[Technical Field]

[0001] The present invention relates to a drive unit for a press device and a press device.

[0002] Known presses for pressing fixtures and the like include an electric or electrohydraulic drive unit. A press tool is connected to the drive unit, and the press tool has press jaws that are pivotable about respective pivot axes. The drive unit moves a movable piston to transmit force from the drive unit to the press jaws of the press tool. Here, movement of the piston pushes first ends of the press jaws of the press tool apart, causing the press jaws to swing about the pivot axis and second ends of the press jaws to move toward each other, generating a pressing force.

[0003] When different press tools are used, it may be necessary to adjust the piston stroke used to generate different press strokes or press energies for each press tool.

[0004] EP1979110 proposes adjusting the piston's stop position during return to achieve different piston end positions. This changes the piston's starting position for the next press, allowing different piston travel distances to be achieved by changing the end position or piston stop position, respectively. However, EP1979110 has the disadvantage that when the piston stop position is changed, the piston return spring remains preloaded even when not in use. In EP1979110, the travel distance can only be changed during a press operation. The piston must move beyond the new piston position. Therefore, adjusting the press path is tedious and time-consuming. At the same time, because only the piston stop end position is adjusted, the length of the drive unit is based on the maximum travel distance. This results in an excessively long drive unit, which is unwieldy and therefore difficult for the user to operate. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE INVENTION It is an object of the present invention to provide a drive unit for a press apparatus, which allows the piston stroke or pressing path for actuating a press tool to be adjusted in a simple manner. [Means for solving the problem]

[0006] This object is achieved by a drive unit according to claim 1 and a pressing device according to claim 12.

[0007] The drive unit of the press device according to the present invention includes a housing and a drive unit arranged within the housing. The drive unit may be an electric drive unit or an electrohydraulic drive unit. Furthermore, a piston is provided that can be moved by the drive unit from a stop position to a pressing position in order to transmit force from the drive unit to a press tool that can be connected to the drive unit. The piston can have a sliding or rotating element that contacts the contact surface of the press tool and moves along the contact surface of the press tool to transmit the force. Furthermore, the piston can be connected to a return spring, and after pressing, for example after the drive unit is switched off, the piston returns from the pressing position to a stop or end position by the return spring. A new pressing can then be performed in which the piston is again moved from the same stop position to the pressing position.

[0008] According to the present invention, the drive unit includes a connection element connected to the housing. The connection element has a receiving portion for receiving or connecting a press tool. Therefore, when connected to the drive unit, the press tool is connected to the connection element, which is then connected to the housing of the drive unit via the receiving portion of the connection element. In particular, the relative position between the press tool and the connection element is fixed and unchangeable by the receiving portion. The connection element is lockable in at least a first position and a second position, and the distance between the stop position of the piston and the receiving portion is different between the first position and the second position. That is, the relative distance between the receiving portion of the connection element and the stop position of the drive unit or the piston is different between the first position and the second position. This allows the effective travel distance of the piston to be easily changed. For example, if the relative distance between the receiving portion and the stop position of the piston is smaller in the first position than in the second position, the piston travel distance can be shortened in the first position, thereby achieving a shorter press path or lower press energy compared to the second position. In contrast, a press tool requiring higher press energy can be used in the second position. By changing the position of the connecting element between the first and second positions without changing the piston's stop position, the return spring is always preloaded evenly. The position of the connecting element is always changed when the piston is in the stop position, for example when the drive is switched off. However, at the same time, the connecting element can be moved to the second position for easier transport and handling of the drive unit, thereby reducing the overall length of the drive unit.

[0009] Preferably, the distance between the first position and the second position is at least 20 mm, preferably at least 40 mm, particularly preferably at least 60 mm, e.g., in the first position, the receiver can be at least 20 mm, preferably at least 40 mm, particularly preferably at least 60 mm further from the stop position of the piston than in the second position.

[0010] Preferably, the maximum travel distance, ie the distance between the rest position of the piston and the pressing position of the piston, is greater than or equal to 60 mm, in particular greater than or equal to 80 mm, preferably greater than or equal to 100 mm.

[0011] Preferably, the connecting element is connected to the housing in a telescopic manner. In this case, the connecting element is insertable into the housing or is substantially or at least partially enclosed by the housing. Alternatively, the connecting element at least partially surrounds the housing. In particular, the connecting element has a sleeve that surrounds the housing. The sleeve can be arranged on the end of the connecting element facing the housing.

[0012] Preferably, the connecting element comprises a first locking device and / or a second locking device for locking the connecting element in the first position or the second position. Here, the first locking device can also be used to lock the connecting element in the first position and the second position, so that a common locking device can be provided for the first position and the second position. Preferably, the first locking device and / or the second locking device can be a fixed stop between the connecting element and the housing of the drive unit.

[0013] Preferably, the first locking device and the second locking device are of the same design or different designs.

[0014] Preferably, the first and / or second locking device is a spring-loaded latch element. In particular, the latch element is formed in the form of a locking pin, a latch ball, or a bayonet catch. For example, the latch element can be provided on the connecting element and inserted into a corresponding recess in the drive unit housing to lock the connecting element in the first and / or second position. In particular, the latch element is positively engaged by the recess. Of course, the latch element can also be connected to the housing and inserted into a corresponding recess in the connecting element.

[0015] Preferably, the latch element is one or more latch balls, and the connecting element has a corresponding number of openings for receiving the latch balls. In particular, the openings are disposed in a sleeve of the connecting element. In particular, the sleeve has a wall thickness smaller than the diameter of the one or more latch balls, so that when the latch balls are disposed in the openings of the connecting element or sleeve, each latch ball protrudes beyond the sleeve of the connecting element. Furthermore, the housing has recesses, and the one or more latch balls are simultaneously disposed in the respective openings and recesses to lock the connecting element in the first position or the second position. As a result, the connecting element is locked so that it cannot be displaced relative to the housing.

[0016] Preferably, the recess on the housing in the first and / or second position is formed at least partially, in particular as a completely circumferential annular groove, into which the latch ball protrudes onto the sleeve of the connecting element when locked, so that, in particular, the connecting element can be rotated relative to the housing and locked in any of the first and / or second positions.

[0017] Preferably, an operating element is provided that covers the opening of the connecting element, the operating element being displaceable and having one or more recesses. When the connecting element is released, the operating element is displaced so that one of the recesses at least partially corresponds to one of the openings, and the latch ball is simultaneously positioned in the opening and the recess and no longer engages with the recess in the housing. This allows the latch ball to displace from the recess in the housing into the recess in the operating element, allowing the housing to be moved relative to the connecting element. In particular, in the locked position, the recess does not coincide with the opening. In particular, the operating element then forms a flat abutment surface against the sleeve surface of the connecting element, thereby retaining or locking the latch ball in the opening of the connecting element and simultaneously engaging the latch ball in the recess in the housing. In this way, locking is achieved against relative displacement of the connecting element relative to the housing, and relative displaceability is ensured, provided that the recess in the operating element at least partially corresponds to the opening for receiving the latch ball.

[0018] Preferably, the first and / or second locking device is a frictional connection. In particular, the frictional connection can be formed by a clamping cone. Thus, when a force is applied, for example by axially moving the piston, in particular by spreading the clamping cone, the frictional connection can generate a clamping force, locking the connecting element in the corresponding position. When the piston reaches the pressing position and returns to the rest position, the frictional connection can be released, allowing the connecting element to be adjusted from the first position to the second position, or vice versa.

[0019] Preferably, more than two positions, in particular continuous adjustment of the connecting element, are possible, so that different travel distances of the piston can be easily realized and in particular the piston travel distance can be continuously adapted to the respective press tool.

[0020] Preferably, the connecting element has a screw thread, which allows the position of the connecting element to be changed. That is, the distance between the receiving part of the connecting element and the stop position of the piston can be changed by screwing the connecting element into the housing of the drive unit or vice versa. In particular, such a screw thread allows continuous adjustment of the connecting element. In particular, the screw thread can have receiving parts corresponding to a first position and a second position, whereby the connecting element can engage with a receiving part, in particular having the shape of a recess, thereby locking the connecting element in the first or second position (or other position).

[0021] Preferably, the stop position of the piston is not variable. In contrast to the prior art of EP 1979110, the stop position of the piston is not variable in the present invention. Whereas in EP 1979110 the start position of the piston movement is changed to adjust the relative distance between the piston and the receiving part, in the present invention the position of the connecting element is changed to change this distance.

[0022] The present invention also relates to a press device comprising such a drive unit. The press device further comprises a press tool, which is connected to a receptacle of the connecting element. In particular, the press tool is removably connected to the connecting element. Alternatively, the press tool can be fixedly connected to the connecting element and replaced together with the connecting element. In this case, the connecting element is removably connected to a housing of the drive unit and is replaceable. The present invention will be described in more detail below by way of preferred embodiments with reference to the accompanying drawings. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a cross-sectional view of a drive unit according to the present invention in a first position. [Figure 2] FIG. 2 is a second cross-sectional view of the drive unit according to FIG. [Figure 3] 2 is a cross-sectional view of the drive unit according to FIG. 1 in a second position; [Figure 4] 1 shows a further embodiment of a drive unit according to the invention in the first configuration. [Figure 5] 5 shows a drive unit according to FIG. 4 in a further configuration. [Figure 6] 5 shows a drive unit according to FIG. 4 in a further configuration. [Figure 7] FIG. 5 is a detailed view of the drive unit of FIG. 4. [Figure 8] 1 shows a further embodiment of a drive unit according to the invention in the first configuration. [Figure 9] 9 shows a drive unit according to FIG. 8 in a further configuration. [Figure 10] 9 shows a drive unit according to FIG. 8 in a further configuration. [Figure 11] 9 shows a drive unit according to FIG. 8 in a further configuration. [Figure 12] FIG. 9 is a detailed view of the drive unit of FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0024] The drive unit 10 according to the present invention includes a housing 12. A drive 22 is disposed within or connected to the housing 12. The drive 22 may be an electric or electrohydraulic drive. The drive 22 moves a piston 14 from a rest position shown in FIGS. 1, 2, and 3 to a pressing position according to arrow 13. The piston 14 has a roller 16 at one end, which contacts a contact surface of a press tool (not shown) and spreads the press jaws of the press tool. The press jaws are rotatable via pivot points or pivot legs, respectively, so that the ends of the press jaws facing the contact surfaces are pressed together, thereby transmitting the force of the drive 22 to the press jaws via the piston 14 and pressing the press tool or workpiece. After the pressing operation is completed, the drive 22 is switched off, and the piston 14 is returned from the pressing position to its rest position by a return spring 15.

[0025] A connecting element 18 is connected to the housing 12. As shown in the figure, the connecting element 18 partially surrounds the housing 12 and is telescopically connected to the housing 12 in the example shown. Of course, the reverse is also possible, so that the housing 12 at least partially surrounds the connecting element 18. The connecting element 18 comprises a receiving part 20, which in the example shown is designed as a bolt. The press tool is detachably connected to the drive unit 10 by means of the bolt. Different press tools can therefore be connected to the drive unit 10.

[0026] According to the present invention, the connecting element 18 can be locked in a first position shown in FIGS. 1 and 2 and a second position shown in FIG. 3. In the first position, the distance between the piston 14 and the receiving part 20 in its stop position is L1. In the second position, the distance between the piston 14's stop position and the receiving part 20 is L2. L1 is smaller than L2. Here, L1 and L2 represent the maximum travel distance / pressing path of the connecting element in the first position and the second position. For example, L1 can be 20 mm to 80 mm, preferably 40 mm to 60 mm, and L2 can be 40 mm to 120 mm, preferably 60 mm to 100 mm. Thus, the relative distance of the receiving part 20 from the stop position of the piston 14 can be adjusted. This changes the maximum travel distance of the piston 14, thereby adjusting the force transmitted to the press jaws and / or the pressing path covered by the press jaws during pressing. Thus, the drive unit 10 can be connected to different press tools and adjust the respective pressing parameters. As shown in Figures 1, 2 and 3, the end position of the piston 14 is always the same. In contrast to the prior art, in the present invention the stop position of the piston is not changed. Rather, the distance between the receiving part 20 and the stop position of the piston 14 is achieved by changing the position of the connecting element 18.

[0027] According to the invention, the housing 12 is provided with a first recess 24 and a second recess 24' for this purpose. Furthermore, the connecting element has a locking device 26 formed as a locking pin. By inserting the locking pin into the recess 24', the connecting element 18 can be locked in a first position. To change the position of the connecting element 18, the locking pin of the locking device 26 can be pulled out of the recess 24', in particular against a spring load, after which the position of the connecting element 18 relative to the housing 12 can be changed and the locking pin can be inserted into the recess 24 to lock the connecting element in a second position. Two locking pins are shown as the locking device in the figures. However, the number of locking pins is not limited to this. Therefore, only one locking pin or more than two locking pins can be provided as the locking device 26.

[0028] Although only two positions are shown in the figures, further positions can be provided in the illustrated example by adding further recesses. Although the locking device is shown as a locking pin in the illustrated example, other locking devices such as friction connections, screw connections, etc. can also be used to lock the connecting element 18 in the respective position.

[0029] By adjusting the position of the connecting element 18 rather than the end stop position of the piston 14, the overall length H1 of the drive unit 10 can always be in the first position, e.g., for transport or handling, so that the drive unit has an overall length H1 that is smaller than the overall length H2 of the connecting element 18 in the second position.

[0030] In the following, reference will be made to the embodiments shown in Figures 4 to 7, where the same or identical components are given the same reference numerals.

[0031] In the embodiment of Figures 4 to 7, the locking device has a latch ball 36. Furthermore, as shown in Figure 4, the housing 12 is formed with a first recess 32' for locking the connecting element 18 in a first position and a second recess 32 for locking the connecting element 18 in a second position. The first recess 32' and / or the second recess 32 are particularly configured as annular grooves. Because the recesses 32, 32' are configured as annular grooves, the connecting element 18 can be freely rotated relative to the housing 12 without releasing the lock between the connecting element 18 and the housing 12.

[0032] The latch ball 36 is disposed in an opening 35 in the sleeve 31 of the connecting element 18. Here, the latch ball 36 is located within the wall thickness D of the sleeve. 314 and 6, the latch ball 36 projects into the respective recess 32, 32' and locks the connecting element 18 to the housing 12. In FIG. 4, the connecting element 18 is shown in the second position, so that the distance L2 between the stop position of the piston 14 and the receiving part 20 is greater than the distance L1 shown in FIG. 6 between the stop position of the piston 14 and the receiving part 20 in the first position. For this purpose, the latch ball 36 is locked in the first recess 32' in the first position.

[0033] Furthermore, an operating element 30 is provided, which is displaceable according to arrow 38 and pre-tensioned in the locked position by one or more springs 33. In the locked position shown in FIGS. 4 and 6, the spring tension of the spring 33 positions the operating element 30 so that the recess 34 of the operating element is not positioned over the opening 35 of the sleeve 31. Therefore, the latch ball 36 cannot be displaced radially outward into the recess 34. As shown in FIGS. 5 and 7, only when the operating element 30 is displaced axially according to arrow 38, the recess 34 is positioned radially adjacent to the opening 35, and the latch ball 36 can be displaced radially outward from the recess 32 or 32' into the recess 34 of the operating element. Here, the recess 34 of the operating element 30 can also be configured as an annular groove to allow the operating element 30 to rotate relative to the connecting element 18. Alternatively, the operating element 30 is not rotatable relative to the connecting element 18, and the rotational position of the operating element 30 relative to the connecting element is fixed. As a result, the depressions 34 of the operating element can be configured as spherical recesses, the number of which corresponds to the number of latch balls 36. Thus, the connecting element 18 can be unlocked from the housing 12 and moved from the first position to the second position or vice versa. When the operating element is then released again by the user, the spring tension of the spring 33 allows the latch ball 36 to be displaced radially inward into one of the recesses 32, 32', while the operating element returns to the locked position. The inner surface of the operating element 30 is again placed flat directly above the opening 35 of the sleeve 31, and the connecting element 18 is again locked to the housing 12.

[0034] In the following, reference will be made to the embodiments shown in Figures 8 to 12, where the same or identical components are provided with the same reference numerals.

[0035] In a further embodiment shown in FIGS. 8 to 12, the operating element 30 has two recesses 34, 34'. Thus, when the connecting element 18 is moved from the second position shown in FIG. 9 to the first position shown in FIG. 11, the operating element 30 is axially displaced in the drive direction according to arrow 39 against the spring force of the first spring 33. This allows the latch ball 36 to be radially displaced within the first recess 34 of the operating element 30. As soon as the latch ball 36 is positioned in the opening 35 of the sleeve 31 and the recess 34, the operating element 30 and the connecting element 18 are simultaneously moved from the first position to the second position. This movement is shown in FIG. 10. Thus, the axial movement of the connecting element 18 along arrow 14 is caused by a corresponding axial movement of the operating element 30 along arrow 39. Upon reaching the first position shown in FIG. 11, the operating element 30 is released and returns to its closed position due to the spring force of the first spring 33.

[0036] When the connecting element 18 is displaced from the first position shown in Figure 11 to the second position, the operating element 30 is displaced in the direction of the arrow 42 (also shown in Figure 11) against the spring force of the second spring 33'. As the operating element 30 is displaced, the latch ball 36 is simultaneously positioned in the opening 35 of the sleeve 31 and the second recess 34' of the operating element 30, and at the same time, the connecting element 18 is also displaced. This means that the drive unit can be operated with one hand to move from the first position to the second position or vice versa.

Claims

1. Housing, a drive unit disposed within the housing; and a connecting element connected to the housing and having a receiving portion for connecting to a press tool; a piston movable by the drive unit from a rest position to a pressing position to transmit force from the drive unit to the press tool; The connecting element is lockable in at least a first position and a second position, and a distance between the stop position of the piston and the receiving portion is different between the first position and the second position.

2. 2. A drive unit according to claim 1, wherein the distance between the first position and the second position is at least 20 mm, preferably at least 40 mm.

3. 3. The drive unit according to claim 1 or 2, wherein the connecting element comprises a first locking device and / or a second locking device for locking the connecting element in the first position or the second position.

4. The drive unit of claim 3 , wherein the first locking device and the second locking device are of the same or different design.

5. 5. The drive unit according to claim 3 or 4, wherein the first locking device and / or the second locking device are in particular spring-loaded latch elements.

6. 6. The drive unit of claim 5, wherein the latch element is one or more latch balls, the connecting element has a corresponding number of openings for receiving the latch balls, the housing has recesses, and the one or more latch balls are simultaneously positioned within corresponding openings and recesses to lock in the first position or the second position.

7. 7. The drive unit according to claim 6, further comprising an operating element covering the opening of the connecting element, the operating element being displaceable and having one or more recesses, and when the connecting element is released, the operating element is displaced so that one of the recesses corresponds to one of the openings, and the latch ball is simultaneously positioned in the opening and the recess and no longer engages with the recess of the housing.

8. 6. A drive unit according to claim 3, wherein the first locking device and / or the second locking device is a friction connection, in particular a clamping cone.

9. 9. A drive unit according to any one of claims 1 to 8, characterized by more than two positions, in particular continuous adjustment of the connecting element.

10. 10. A drive unit according to claim 1, wherein the connecting element has a screw thread, by means of which the position of the connecting element can be changed.

11. A drive unit according to any preceding claim, wherein the stop position of the piston is not alterable.

12. A pressing device comprising a drive unit according to any one of claims 1 to 11 and a pressing tool, the pressing tool being connected to the receiving part of the connecting element.

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