Drive unit for a pressing unit

Abstract

A drive unit (10) for a pressing unit with a housing (12), a drive (22) which is arranged in the housing (12), a piston (14) which can be moved by the drive (22) from a stop position into a pressing position in order to transmit the force from the drive (22) to a pressing tool which can be connected to the drive unit (10), and a connecting element (18) which is connected to the housing (12) and has a receptacle (20) for connecting to a pressing tool, wherein the connecting element (18) can be locked in at least a first position and a second position, wherein a spacing (L2) between the stop position of the piston (14) and the receptacle (20) is different in the first position and in the second position.

Description

[0001] Drive unit for a press device

[0002] The present invention relates to a drive unit for a pressing device and a pressing device.

[0003] Known pressing devices for pressing press fittings or the like have a drive unit with an electric or electro-hydraulic drive. A pressing tool is connected to the drive unit, wherein the pressing tool has pressing jaws that can be pivoted about respective pivot axes. The drive moves a movable piston to transfer the force from the drive to the pressing jaws of the pressing tool. The movement of the piston pushes first ends of the pressing jaws of the pressing tool apart, so that the pressing jaws are pivoted about the pivot axis, and second ends of the pressing jaws are moved toward each other to generate the pressing force.

[0004] When using different pressing tools, it may be necessary to adjust the piston stroke used to generate a different pressing stroke or pressing energy for the respective pressing tools.

[0005] EP 1979110 proposes adjusting the piston stop position during the piston return stroke to achieve different end positions of the piston during the piston return stroke. This changes the starting position of the piston during the next pressing operation, so that a different piston travel path can be achieved by changing the end position or piston stop. However, EP 1979110 has the disadvantage that if the piston stop is changed, the piston return spring remains in an increased preloaded state even when not in use. Changing the travel path in EP 1979110 is only possible during a pressing operation. The piston must then be moved beyond the position of the new piston stop. Adjusting the pressing path is therefore cumbersome and time-consuming.At the same time, the length of the drive unit is determined by the maximum travel distance, since only the end position of the piston stop is adjusted. This results in an excessively long drive unit, which is unwieldy and thus difficult for the user to operate.

[0006] The object of the present invention is to provide a drive unit for a pressing device in which the piston stroke or pressing path for actuating the pressing tool can be easily adjusted.

[0007] The object is achieved by a drive unit according to claim 1 and a pressing device according to claim 12.

[0008] The drive unit according to the invention for a pressing device has a housing and a drive arranged in the housing. The drive can be an electric drive or an electro-hydraulic drive. Furthermore, a piston is provided which can be moved by the drive from a stop position into a pressing position for transmitting the force from the drive to a pressing tool connectable to the drive unit. The piston can have sliding elements or rolling elements which come into contact with contact surfaces of the pressing tool and are moved along the contact surfaces of the pressing tool to transmit the force. Furthermore, the piston can be connected to a return spring so that after pressing and, for example, after the drive is switched off, the piston is moved back from the pressing position to a stop position or end position due to the return spring.A new pressing can then take place, in which the piston is again moved from the same stop position into the pressing position.

[0009] According to the invention, the drive unit has a connecting element connected to the housing. The connecting element has a receptacle for receiving or connecting to a pressing tool. Thus, when connected to the drive unit, the pressing tool is connected to the connecting element by the receptacle of the connecting element and then to the housing of the drive unit. In particular, the relative position between the pressing tool and the connecting element is fixed and unchangeable by the receptacle. The connecting element can be locked in at least a first position and a second position, wherein a distance between the stop position of the piston and the receptacle is different in the first position and in the second position. Thus, the relative distance between the receptacle of the connecting element and the drive unit or the stop position of the piston differs in the first position and the second position.This makes it easy to change the effective travel distance of the piston. If, for example, the relative distance between the holder and the stop position of the piston is smaller in the first position than in the second position, a shorter travel distance of the piston can be achieved in the first position, which means a shorter pressing distance or lower pressing energy can be achieved than in the second position. On the other hand, a pressing tool that requires higher pressing energies can be used in the second position. By changing the position of the connecting element in the first position and in the second position without changing the stop position of the piston, the return spring is always preloaded to the same extent. The change in the position of the connecting element always occurs in a force-free state when the piston is in the stop position, for example when the drive is switched off.At the same time, however, the connecting element can be moved to the second position for transport or handling of the drive unit, thereby reducing the overall length of the drive unit.

[0010] Preferably, the distance between the first position and the second position is at least 20 mm, preferably at least 40 mm, and particularly preferably at least 60 mm. Thus, in the first position, the receptacle can be at least 20 mm, preferably at least 40 mm, and particularly preferably at least 60 mm further away from the stop position of the piston than in the second position.

[0011] Preferably, the maximum travel distance, i.e. the distance between the stop position of the piston and the pressing position of the piston, is 60 mm or more, in particular 80 mm or more and preferably 100 mm or more.

[0012] Preferably, the connecting element is telescopically connected to the housing. The connecting element can be inserted into the housing or is substantially or at least partially surrounded 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 at the housing-side end of the connecting element.

[0013] The connecting element preferably has a first locking device and / or a second locking device for locking the connecting element in the first position and the second position, respectively. 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 is provided for the first position and the second position. The first locking device and / or the second locking device can preferably be a fixed stop between the connecting element and the housing of the drive unit.

[0014] Preferably, the first locking device and the second locking device are designed the same or different.

[0015] The first locking device and / or the second locking device is preferably a spring-loaded locking element. In particular, the locking element is designed as a locking pin, locking ball, or in the form of a bayonet lock. The locking element can be provided, for example, on the connecting element and inserted into corresponding recesses in the housing of the drive unit to lock the connecting element in the first position and / or second position. In particular, the locking element is positively received in the recesses. Of course, the locking element can also be connected to the housing and inserted into corresponding recesses in the connecting element.

[0016] The locking element preferably comprises one or more locking balls, the connecting element having a corresponding number of openings for receiving the locking balls. In particular, the openings are arranged in the sleeve of the connecting element. In this case, the sleeve in particular has a wall thickness that is smaller than the diameter of the one or more locking balls, so that, if the locking balls are arranged in the openings of the connecting element or the sleeve, the respective locking ball protrudes beyond the sleeve of the connecting element. Furthermore, the housing has recesses, the one or more locking balls being arranged simultaneously in the respective opening and the recess for locking in the first position or in the second position. This locks the connecting element so that it cannot be moved relative to the housing.Preferably, the recess on the housing at the first position and / or at the second position is formed as an at least partially and in particular completely circumferential annular groove into which the locking balls protrude over the sleeve of the connecting element when locked. Thus, in particular, the connecting element is rotatable relative to the housing and can be locked in any position in the first position and / or the second position.

[0017] Preferably, an operating element is provided which covers the opening of the connecting element, wherein the operating element is displaceable and has one or more recesses, wherein upon release of the connecting element, the operating element is displaced such that one of the recesses at least partially coincides with one of the openings and the locking balls are arranged simultaneously in the opening and the recess and are no longer engaged with the recess in the housing. The locking ball can thus be displaced out of the recess in the housing into the recess of the operating element and thus enable mobility of the housing relative to the connecting element. In particular, in a locking position, the recess is not in line with an opening.In particular, the operating element then forms a contact surface that lies flush against the surface of the sleeve of the connecting element, thereby holding or locking the locking ball in the opening of the connecting element, so that the locking ball simultaneously engages the recess in the housing. This ensures locking with respect to relative displacement of the connecting element to the housing and relative displaceability, provided the recesses of the operating element at least partially coincide with the openings for receiving the locking ball.

[0018] Preferably, the first locking device and / or the second locking device is a frictional connection. In particular, the frictional connection can be created by a clamping cone. Thus, for example, a clamping force can be generated by the frictional connection when a force is applied by moving the piston in the axial direction, in particular by pushing the clamping cone apart, so that the connecting element is locked in the corresponding position. Once the piston has reached the pressing position and returned to the stop position, the frictional connection can be released, and the connecting element can be adjusted from its first position to the second position or vice versa.

[0019] Preferably, more than two positions and, in particular, continuous adjustment of the connecting element are possible. This allows for easy implementation of different piston travel paths and, in particular, continuous adaptation of the piston travel path to the respective pressing tool.

[0020] The connecting element preferably has a thread, wherein the position of the connecting element can be changed by the thread. Thus, the connecting element can be screwed into the housing of the drive unit or vice versa to change the distance between the receptacle of the connecting element and the stop position of the piston. In particular, such a thread enables continuous adjustment of the connecting element. In particular, the thread can have notches that correspond to the first position and second position, so that engagement in the notches, which are particularly designed as a recess, can occur and the connecting element is thereby locked in the first position or the second position (or in other positions).

[0021] Preferably, the stop position of the piston is not changeable. In contrast to the prior art of EP 1979110, the stop position of the piston is not changeable in the present invention. While in EP 1979110, the starting position for the piston movement is changed to adjust the relative distance between the piston and the receptacle, in the present invention, the position of the connecting element is changed to change this distance.

[0022] Furthermore, the present invention relates to a pressing device with a drive unit as described above. Furthermore, the pressing device has a pressing tool, wherein the pressing tool is connected to the receptacle of the connecting element. In particular, the pressing tool is detachably connected to the connecting element. Alternatively, it is also possible for the pressing tool to be firmly connected to the connecting element and to be replaceable together with the connecting element. In this case, the connecting element would be detachably connected to the housing of the drive unit and could be replaced. The invention is explained in more detail below using preferred embodiments with reference to the accompanying drawings.

[0023] They show:

[0024] Figure 1 shows a drive unit according to the present invention in a sectional view in a first position,

[0025] Figure 2 shows the drive unit according to Figure 1 in a second sectional view,

[0026] Figure 3 shows the drive unit according to Figure 1 in a sectional view in a second position,

[0027] Figure 4 shows a further embodiment of the drive unit according to the present invention in a first configuration,

[0028] Figure 5 shows the drive unit according to Figure 4 in a further configuration, Figure 6 shows the drive unit according to Figure 4 in a further configuration,

[0029] Figure 7 is a detailed view of the drive unit of Figure 4,

[0030] Figure 8 shows a further embodiment of the drive unit according to the present invention in a first configuration,

[0031] Figure 9 shows the drive unit according to Figure 8 in a further configuration,

[0032] Figure 10 shows the drive unit according to Figure 8 in a further configuration,

[0033] Figure 11 shows the drive unit according to Figure 8 in a further configuration and

[0034] Figure 12 shows a detailed view of the drive unit of Figure 8.

[0035] The drive unit 10 according to the invention has a housing 12. A drive 22 is arranged in the housing 12 or is connected to the housing 12. The drive 22 can be an electric or an electro-hydraulic drive. By means of the drive 22, a piston 14 is moved according to the arrow 13 from a stop position shown in Figures 1, 2 and 3 into a pressing position. The piston 14 has rollers 16 at one end, which come into contact with contact surfaces of a pressing tool (not shown) and thus press the pressing jaws of the pressing tool apart. The pressing jaws can each be pivoted about a pivot point or pivot axis, so that the end of the pressing jaws opposite the contact surfaces is pressed together and the force of the drive 22 is thereby transmitted via the piston 14 to the pressing jaws for pressing a press fitting or a workpiece.After the pressing operation has been carried out, the drive 22 is switched off and the piston 14 is moved back from the pressing position to the stop position by means of a return spring 15.

[0036] A connecting element 18 is connected to the housing 12. As shown in the figures, the connecting element 18 partially surrounds the housing 12 and, in the example shown in the figures, is telescopically connected to the housing 12. Of course, this can also be done the other way around, so that the housing 12 at least partially surrounds the connecting element 18. The connecting element 18 has a receptacle 20, which, in the examples shown in the figures, is designed as a bolt. A pressing tool is detachably connected to the drive unit 10 by means of the bolt. Thus, different pressing tools can be connected to the drive unit 10.

[0037] According to the invention, the connecting element 18 can be locked in a first position, shown in Figures 1 and 2, and a second position, shown in Figure 3. In the first position, the distance of the piston in the stop position from the receptacle 20 is designated by Li. In the second position, the distance between the stop position of the piston 14 and the receptacle 20 is designated by L2. Here, Li is smaller than l_2. Here, Li and l_2 designate the maximum travel paths / compression paths for the first position of the connecting element and for the second position of the connecting element. Li can, for example, be 20 mm to 80 mm and preferably 40 mm to 60 mm, whereby L2 can, for example, be 40 mm to 120 mm and preferably 60 mm to 100 mm. The relative distance of the receptacle 20 from the stop position of the piston 14 can thus be adjusted.This changes the maximum possible travel of the piston 14, thereby adjusting the force transmitted to the pressing jaws and / or the pressing path covered by the pressing jaws during pressing. The drive unit 10 can thus be connected to different pressing tools, whereby an adjustment of the respective pressing parameters is possible. 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, the stop position of the piston is therefore not changed in the present invention. Rather, the distance between the receptacle 20 and the stop position of the piston 14 is achieved by changing the position of the connecting element 18.

[0038] According to the invention, the housing 12 has first recesses 24 and second recesses 24'. Furthermore, the connecting element has locking devices 26, which are designed as locking pins. The connecting element 18 can be locked in the first position by inserting the locking pin into the recesses 24'. To change the position of the connecting element 18, the locking pins of the locking device 26 can be pulled out of the recesses 24', in particular against a spring load, then the position of the connecting element 18 relative to the housing 12 is changed and the locking pins are inserted into the recesses 24 to lock the connecting element in the second position. In the figures, two locking pins are shown as the locking device. However, the number of locking pins is not limited to this.Thus, only one locking pin or more than two locking pins can be provided as the locking device 26.

[0039] Although only two positions are shown in the figures, additional positions can be provided by adding further recesses in the illustrated example. Although the example in the figures depicts the locking device as locking pins, other locking mechanisms, such as a friction fit, a screw connection, or the like, can be used to lock the connecting element 18 in the respective positions.

[0040] Because the position of the connecting element 18 is adjusted rather than the end stop of the piston 14, the total length Hi of the drive unit 10 can always be set to the first position, for example, for transport or handling. As a result, the drive unit has a total length Hi that is smaller than the total length H2 in the second position of the connecting element 18.

[0041] Reference is made below to the embodiment of Figures 4 - 7. Identical or identical components are identified by the same reference numerals.

[0042] In the embodiment of Figures 4-7, the locking device has detent balls 36. Furthermore, 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 are formed in the housing 12, shown in Figure 4. The first recess 32' and / or the second recess 32 are in particular designed as an annular groove. Due to the design of the recesses 32, 32' as an annular groove, free rotation of the connecting element 18 relative to the housing 12 is possible without the locking between the connecting element 18 and the housing 12 having to be released.

[0043] The locking balls 36 are arranged in openings 35 in the sleeve 31 of the connecting element 18. The locking balls 36 have a radius that is thicker than the wall thickness D31 of the sleeve. Thus, a portion of the locking balls 36 always projects beyond the sleeve. In a locking position, shown in Figures 4 and 6, the locking ball 36 projects into one of the respective recesses 32, 32' and thereby locks the connecting element 18 relative to the housing 12. In Figure 4, the connecting element 18 is shown in a second position, such that the distance l_2 between the stop position of the piston 14 and the receptacle 20 is greater than the distance Li shown in Figure 6 between the stop position of the piston 14 and the receptacle 20 in the first position. For this purpose, the locking ball 36 is locked in the first recess 32' in the first position.

[0044] Furthermore, an operating element 30 is provided which is displaceable according to arrow 38 and is pretensioned into a locking position by one or more springs 33. In the locking position, shown in Figures 4 and 6, the operating element 30 is arranged due to the spring tension of the springs 33 such that recesses 34 in the operating element are not arranged above the openings 35 in the sleeve 31. Locking balls 36 can therefore not be displaced radially outwards into the recesses 34. Only when the operating element 30 is displaced according to arrow 38 in the axial direction, as shown in Figures 5 and 7, are the recesses 34 arranged directly radially next to the openings 35, so that the locking balls 36 can be displaced radially outwards from the recesses 32 or 32' into the recesses 34 of the operating element.In this case, the recesses 34 of the operating element 30 can also be designed as an annular groove to enable 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, so that the relative position of the operating element 30 to the connecting element is fixed in the direction of rotation. As a result, the recesses 34 in the operating element can be designed as spherical recesses, the number of these spherical recesses corresponding to the number of detent balls 36. Thus, the locking of the connecting element 18 relative to the housing 12 can be released, and the connecting element 18 can be moved from the first position to the second position, or vice versa.If the user then releases the control element, the spring tension of the spring 33 causes the control element to return to its locking position as soon as the locking ball 36 can be displaced radially inward into one of the recesses 32, 32'. An inner surface of the control element 30 is then again flat and arranged directly above the opening 35 of the sleeve 31, thus again locking the connecting element 18 relative to the housing 12.

[0045] Reference is made below to the embodiment of Figures 8 - 12. Identical or identical components are identified by the same reference numerals.

[0046] In a further embodiment, shown in Figures 8-12, the operating element 30 has two recesses 34, 34'. If the connecting element 18 is thus moved from the second position, shown in Figure 9, to the first position, shown in Figure 11, the operating element 30 is displaced axially in the direction of the drive according to the arrow 39, against the spring force of the first spring 33. The detent ball can then be displaced radially into the first recess 34 of the operating element 30. As soon as the detent ball 36 is arranged in the opening 35 of the sleeve 31 and in the recess 34, a simultaneous movement of the operating element 30 and the connecting element 18 from the first position to the second position takes place. This transition is shown in Figure 10. An axial movement along the arrow 14 of the connecting element 18 is thus brought about by a corresponding axial movement of the operating element 30 along the arrow 39.When the first position, shown in Figure 11, is reached, the operating element 30 is released and moved back into the closed position due to the spring force of the first spring 33.

[0047] If the connecting element 18 is moved from the first position, shown in Figure 11, to the second position, the operating element 30 is moved in the direction of arrow 42 (also shown in Figure 11) against the spring force of the second spring 33'. Simultaneously with the movement of the operating element 30, the connecting element 18 is also moved as soon as the locking ball 36 is simultaneously arranged in the opening 35 of the sleeve 31 and the second recess 34' of the operating element 30. This allows one-handed operation of the drive unit to transfer it from the first position to the second position or vice versa.

Claims

Patent claims 1. Drive unit for a pressing device with a housing, a drive arranged in the housing, a connecting element which is connected to the housing and has a receptacle for connection to a pressing tool, a piston which can be moved by the drive from a stop position into a pressing position for transmitting the force from the drive to the pressing tool, and wherein the connecting element can be locked in at least a first position and a second position, wherein a distance between the stop position of the piston and the receptacle is different in the first position and in the second position.

2. Drive unit according to claim 1, characterized in that the distance between the first position and the second position is at least 20 mm and preferably at least 40 mm.

3. Drive unit according to claim 1 or 2, characterized in that the connecting element has a first locking device and / or a second locking device for locking the connecting element in the first position or the second position.

4. Drive unit according to claim 3, characterized in that the first locking device and the second locking device are designed the same or different.

5. Drive unit according to claim 3 or 4, characterized in that the first locking device and / or the second locking device is a locking element, in particular a spring-biased locking element.

6. Drive unit according to claim 5, characterized in that the locking element is one or more locking balls, wherein the connecting element has a corresponding number of openings for receiving the locking balls, wherein the housing has recesses, wherein for locking in the first position or the second position the one or more locking balls are arranged simultaneously in the respective opening and the recess.

7. Drive unit according to claim 6, wherein an operating element is provided which covers the openings of the connecting element, wherein the operating element is displaceable and has one or more recesses, wherein upon release of the connecting element the operating element is displaced such that one of the recesses corresponds to the openings and the locking ball is arranged simultaneously in the opening and the recess and is no longer in engagement with the recess of the housing.

8. Drive unit according to one of claims 3 to 5, characterized in that the first locking device and / or the second locking device is a frictional connection, in particular a clamping cone.

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

10. Drive unit according to one of claims 1 to 9, characterized in that the connecting element has a thread, wherein the position of the connecting element can be changed by the thread.

11. Drive unit according to one of claims 1 to 10, characterized in that the stop position of the piston is not changeable.

12. Pressing device with a drive unit according to one of claims 1 to 11 and a pressing tool, wherein the pressing tool is connected to the receptacle of the connecting element.

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