METHOD AND DEVICE FOR BENDING OF STRAND-SHAPED WORKPIECES

Abstract

The invention relates to a device and method for bending strand-shaped workpieces. A holder for a strand-shaped workpiece is provided. A bending tool comprises at least one radius part and one bending part. The workpiece can be bent by pivoting the bending part about the radius part. Moreover, a workpiece drive shaft that extends at least in a longitudinal direction is provided for driving the bending tool and a positioning device for positioning the bending tool relative to the workpiece. The positioning device enables a displacement of the bending tool and the tool driveshaft in at least one transverse direction that runs transversely to the longitudinal direction. A drive wheel is rotatably arranged around an axis that is fixed relative to the workpiece and is coupled via a transmission device to drive the tool driveshaft. The transmission device has at least one coupling element that can move transverse to the axis of the drive wheel.

Claims

1. A device for the bending of strand-shaped workpieces including a holder for a strand-shaped workpiece, a bending tool, at least comprising a radius part and a bending part, wherein the workpiece can be bent by pivoting the bending part about the radius part, at least one tool driveshaft extending in a longitudinal direction for driving the bending tool, a positioning device for positioning the bending tool relative to the workpiece, wherein the positioning device is configured to enable a displacement of the bending tool and the tool driveshaft in at least one transverse direction that runs transversely to the longitudinal direction, wherein a drive wheel is rotatably arranged around an axis that is fixed relative to the workpiece and is coupled via a transmission device to the drive of the tool driveshaft, and wherein the transmission device comprises at least one coupling element configured to be movable transversely to the axis of the drive wheel.

2. The device according to claim 1, wherein the holder is designed so that the workpiece is aligned in the longitudinal direction.

3. The device according to claim 1, wherein the positioning device is configured to enable a displacement of the bending tool in different directions within a plane arranged transverse to the longitudinal direction.

4. The device according to claim 1, wherein the positioning device comprises at least one slide that can be displaced in at least one transverse direction, wherein at least one slide drive device is provided to move the slide.

5. The device according to claim 4, wherein a first slide is provided that is displaceably guided in a first transverse direction, and a second slide is provided that is displaceably guided in a second transverse direction.

6. The device according to claim 1, wherein the positioning device is configured to enable a rotation of the bending tool about the longitudinal direction.

7. The device according to claim 1, wherein the drive wheel is designed as a drive gear, at least one drive pinion is provided on the tool driveshaft, and the coupling element is designed as a coupling gear which is engaged with the drive pinion and the drive wheel.

8. The device according to claim 7, wherein the coupling gear is connected in each case to the drive pinion and the drive gear by spacing elements such that when the drive pinion moves in the transverse direction, the coupling gear remains engaged with the drive pinion and the drive gear.

9. The device according to claim 1, wherein a motor drive is coupled to the drive wheel, and an activation device is configured to specify an activation of the motor drive depending on the displacement in transverse direction.

10. The device according to claim 9, wherein the activation device is configured to specify a compensating rotation of the drive wheel during the displacement in transverse direction such that a change in the rotary angle relationship caused by the displacement between the drive wheel and the drive pinion is compensated by compensating rotation.

11. The device according to claim 1, wherein the drive wheel is coupled via a transmission shaft to a drive disk, wherein the drive disk can be driven by a motor drive.

12. The device according to claim 1, wherein the drive wheel is rotatably arranged about a common axis with at least one additional drive wheel, wherein the drive wheels are coupled to drive disks via coaxial hollow shafts, wherein a bushing for the workpiece is provided within the hollow shafts.

13. The device according to claim 12, wherein the other drive wheel is provided as a drive for one of the following functions: shifting the bending tool in transverse direction, and/or rotating the bending tool about the longitudinal direction.

14. The device according to claim 1, wherein the holder for the workpiece comprises a clamping device for clamping the workpiece and a bushing for the workpiece.

15. A method for the bending of strand-shaped workpieces, wherein a strand-shaped workpiece is arranged in a holder, and a bending tool, comprising at least one radius part and a bending part pivotable about it, is positioned thereupon to bend the workpiece, wherein the bending tool is driven by at least one tool driveshaft that extends in a longitudinal direction, and the bending tool is positioned relative to the workpiece by a positioning device such that a displacement of the bending tool and the tool driveshaft is possible in at least one transverse direction which runs transversely to the longitudinal direction, wherein a drive wheel, that is rotatably arranged around an axis that is fixed relative to the workpiece and is coupled via a transmission device to drive the tool driveshaft, wherein the transmission device has at least one coupling element that moves transversely to the axis of the drive wheel, is activated to operate the bending tool.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0031] In the following, embodiments of the invention will be further described with reference to the drawings. In the drawings:

[0032] FIG. 1a-1c show side views of a pipe bending machine with a bending tower in different positions.

[0033] FIG. 2 shows a perspective view of the bending tower of the bending machine from FIG. 1 with a bending head.

[0034] FIG. 3 shows a side view of the bending tower and bending head from FIG. 2 with a partially removed housing.

[0035] FIG. 4 shows a perspective view of a tool holder of the bending head from FIG. 2, 3.

[0036] FIG. 5 shows a plan view of the bending tool from FIG. 4.

[0037] FIG. 6 shows a view of the tool holder from FIG. 4 in a longitudinal section;

[0038] FIG. 7 shows a perspective view of the bending head from FIG. 2 without a housing;

[0039] FIG. 8 shows a plan view of the bending head from FIG. 7 without a housing.

[0040] FIG. 9 shows a representation in a longitudinal section of hollow shafts with drive wheels of the bending head.

[0041] FIG. 10 shows a front view of the bending tool from FIG. 7, 8 with elements of a coupling device.

[0042] FIG. 11 shows a perspective view of elements of the coupling device.

[0043] FIG. 12a-12c show front views of elements of the coupling device in different positions.

[0044] FIG. 13 shows a schematic representation of an activation device for different motor drives.

DETAILED DESCRIPTION OF THE INVENTION

[0045] FIG. 1a-1c show a pipe bending machine 10 with a fixed clamping unit 12, relative to which a bending tower 14 in a machine bed 16 can be moved in a longitudinal direction L.

[0046] The bending tower 14 bears a bending head 22 to which a bending tool 26 is attached by a tool holder 24. The bending head 22 can rotate about a longitudinal axis L. Controllable drives 13a (not shown in FIG. 1) and 13b-g are provided for moving the bending tower 14 and rotating the bending head 22. The individual functions of the drives 13a-g will be explained in greater detail below.

[0047] In FIG. 1a, an unbent pipeline 20 is securely clamped in a clamping head 18 of the clamping device 12 so that the pipe 20 is aligned in the longitudinal direction of the axis L. The clamped pipe end remains consistently stationary during the bending process and is not moved or rotated. The bending head 22 has an opening 28 of an axially running passage through which the pipe 20 is inserted. The bending tool 26 is positioned on the pipe 20.

[0048] While the pipe bending machine 10 is operating, the pipe 20 is shaped into a desired bend geometry by the bending tool 26 by applying successive bends as can be seen from the sequence in FIG. 1a to 1c. First the bending point at the furthest distance from the clamped end of the pipe 20 is approached, and the bending tool 26 is positioned there. By means of a rotating mechanism which will be explained further below, the bending head 22 can be rotated about the longitudinal axis L of the pipe 20 so that the bending tool 26 also rotates conjointly and can be activated to create a bend about a bending axis running transverse to the longitudinal axis L.

[0049] The elements of the bending tool 26 can be seen more precisely in FIG. 4, 5. As movable, driven elements, the bending tool 26 comprises a radius roller 30 that can rotate about a bending axis B, a sliding block 32 that can pivot about the bending axis B, and a counter holder 34 that can pivot about a pivot axis S.

[0050] As can be seen in FIG. 4 and also in FIG. 5, the radius roller 30 comprises a plurality of bending grooves 36 at a distance from each other in the longitudinal direction of the radius roller 30 that each extend around a part of the circumference of the radius roller 30. The sliding block 32 comprises associated bending grooves 38 at the same spacing which are arranged on the side of the bending roller 32 facing the radius roller 30.

[0051] To create a bend in the pipeline 20, it is accommodated between the radius roller 30 and the sliding block 32 in one of the radial grooves 36 and one of the bending grooves 38. The different radial grooves 36 and associated bending grooves 38 are provided to accommodate pipelines of different outer diameters.

[0052] By pivoting the sliding block 32 about the bending axis B, a bend of the pipe 20 is generated in a bending plane perpendicular to the bending axis B while simultaneously rotating the radius roller 30.

[0053] The sliding block 32 is pivotably arranged around the radius roller 30. The radius roller 30 is rotatable. Bending by rolling as well as drawing is accordingly possible with the bending tool 26. The sliding block 32 can be pivoted about the radius roller 30 within a pivoting range of at least 180. Depending on the actuation of the radius roller 30 and sliding block 32 in the bending plane, a bend both to the right and left is possible.

[0054] If required by the respective bend which in particular can be the case when bending pipelines with flexible sections, the pivotable counter holder 34 can be placed on the side of the pipe 20. As a lever, the counter holder 34 can pivot about the pivot axis S that runs parallel from the bending axis B at a distance. The counter holder 34 can be moved into the suitable pivot position for each bend. Various grooves to be placed against the side of the pipe 20 are provided one above the other in the counter holder 34 as well.

[0055] In order to shape the initially unbent pipe 20 into a desired bending geometry, a plurality of bends are made sequentially in the above-described manner, wherein the bending tool 26 is relatively positioned at the next bending point by moving the bending tower 14 (see FIG. 1a-1c) along the longitudinal direction L toward the clamping device 12, then, by rotating the bending head 22, the bending tool 26 is positioned about the pipe axis L in the desired bending plane, and subsequently the radius roller 30, sliding block 32, and if applicable counter roller 34 are actuated to create the desired bend.

[0056] FIG. 1a-FIG. 1c sequentially show how the bending tower 14 gradually approaches the clamping device 12 when creating the sequential bends. In so doing, the clamping head 18 arranged on an extension 42 of the clamping device 12 is guided through the opening 28 and passage in the bending head 22 until the last bend is performed. The bent pipe can then be removed.

[0057] As shown in FIG. 1a-FIG. 1c and as can be seen in greater detail in FIG. 2, 4, only the bending tool 26, from which extends only the elongated, relatively thin tool holder 24, is arranged directly on the pipe 20. Since the tool holder 24 is aligned in the longitudinal direction L and extends toward the clamping device 18, a design is achieved in which, proceeding from the bending point, there is only a very small interfering edge, i.e., fixed parts of the bending tool 26, or of its attachment (tool holder 24), which the pipeline can strike when bending, in particular at large bending angles.

[0058] In this process the tubular tool holder 24 serves not only to hold and position the bending tool 26, but also to drive the movable elements 30, 32, 34 of the bending tool 26.

[0059] As can be seen from the longitudinal section in FIG. 6, the tool holder 24 is a hollow pipe that is fastened at one end to the bending tool 26 and at the other end to the bending head. FIG. 6 does not show the entire length of the tool holder 24; in fact, the tool holder is about six times as long as it is wide as, for example, can be seen in FIG. 2, 4.

[0060] Three shafts are coaxially arranged within the interior of the tool holder 24. A solid inner shaft serves as a radius driveshaft 44. A hollow shaft arranged around the radius driveshaft 44 serves as a bending driveshaft 46. Also arranged around the bending driveshaft 46 coaxial thereto is another hollow shaft as a counter holder driveshaft 48.

[0061] As can be seen in FIG. 4 and FIG. 6, three drive pinions 50a, 50b, 50c that are arranged axially next to each other are provided on the inner end of the tool holder 24. As can be seen in FIG. 6, the radial inner radius driveshaft 44 is coupled to the rear-most drive pinion 50a, the bending driveshaft 46 is coupled to the middle pinion 50b, and the outer counter holder driveshaft 48 is coupled to the front pinion 50c.

[0062] As shown in FIG. 6, the rotary movement of the three tool drive shafts 44, 46, 48 is transmitted by corner gears to the radius roller 30, sliding block 32 and counter holder 34.

[0063] For this purpose, corner gears are always provided on the outer end of each of the tool drive shafts 44, 46, 48 by means of which the rotary movement is deflected by bevel gears at an angle of 90 in the depicted example. A first corner gear 52a is formed between a first bevel gear 54a formed on the end of the radius driveshaft 44 and a second bevel gear 56a coupled to the radius roller 30. A second corner gear 52b is formed between a first bevel gear 54b formed on the end of the bending driveshaft 46 and a second bevel gear 56b coupled to the bending roller 32. The bevel gears 54a, 56a of the first corner gear 52a are designed solid, whereas the bevel gears 54b, 56b of the second corner gear 52b are designed hollow and are arranged coaxial to the bevel gears 54a, 56a of the first corner gear 52a. In this manner, rotary movements of the drive pinions 50a, 50b are transmitted via the coaxial tool drive shafts 44, 46 and converted into coaxial rotations of the radius roller 30 and sliding block 32.

[0064] A third corner gear 52c is formed on the bending tool 26 at a distance from the first and second corner gear 52a, 52b. For this purpose, the counter holder driveshaft 48 is designed somewhat shorter than the two other tool driveshafts 44, 46. A first bevel gear 54c is arranged on its end and engages with a second bevel gear 56c which is arranged around the pivot axis S of the counter holder 34. In this manner, a rotary movement of the drive pinion 50c can be transmitted by the counter holder driveshaft 48 and corner gear 52c to the counter holder 34.

[0065] Accordingly, the movable elements 30, 32, 34 on the bending tool 26 can be rotatably driven independently and separate from each other in order to execute desired rotary, or respectively pivoting movements to create desired bends. In doing so the achievable movements are not thereby restricted, so that bends to the right/left are also enabled as well as rolling/draw bending as desired.

[0066] In this process the tool holder 24 makes it possible for the bending tool 26 to be suitably positioned by the bending head 22 in each case, wherein at the same time a drive of the elements 30, 32, 34 of the bending tool 26 is achieved in an extremely compact arrangement with a small interfering edge.

[0067] To position the bending tool 26, the bending head 22 is rotatably arranged about the longitudinal axis L of the pipe 20 as indicated by an arrow in FIG. 2. The bending head 22 has a housing 40 in which a positioning device 62 for the tool holder 24 is arranged on a head plate 60. The housing 40 can be rotated about the longitudinal axis L of the pipe 20 so that the positioning device 62 arranged therein also rotates about the longitudinal axis L with the tool holder 24 and the bending tool 26.

[0068] As can be seen in particular in FIG. 10, the positioning device 62 comprises a first slide 64 and a second slide 66. The slides 64, 66 are each guided in associated rail guides 65,67 on both sides so that the first slide 64 can be displaced to execute an offset movement in a first transverse direction X (in FIG. 10), and the second slide 66 can be displaced to execute a lifting movement in a second transverse direction Y at a right angle thereto. In doing so the slides 64, 66 are driven by the engagement of drive gears in toothed racks 68, 69.

[0069] The first slide 64 forms a side guide by two side frame elements 70 for the tool holder 24 in the X direction, whereas the second slide 66 forms a guide in the Y direction for the tool holder 24. The tool holder 24 can accordingly be displaced in a plane parallel to the head plate 60 into a desired X/Y position so that the bending tool 26 attached thereto executes the desired lift/offset movement.

[0070] In order to ensure that the drive shafts 44, 46, 48 held in the tool holder 24 are consistently driven despite the displaceability of the tool holder 24, a transmission device 72 is provided on the bending head 22. For each of the three tool driveshafts 44, 46, 48, this comprises the associated pinion (FIG. 6) 50a, 50b, 50c, a drive wheel 74a, 74b, 74c each of which being fixedly arranged to the bending head 22, and a coupling gear 76a, 76b, 76c each of which being engaged with the respective pinion 50a, 50b, 50c and drive wheel 74a, 74b, 74c.

[0071] The transmission device 72 is depicted in FIG. 11 once again without housing elements and without the slides 64, 66. The drive wheels 74a, 74b, 74c are connected by first spacing tabs 78 to the coupling gears 76a, 76b, 76c, and these are connected via second spacing tabs 80 to the drive pinions 50a, 50b, 50c on the tool holder 24. A consistent distance and hence continuous engagement between the gears is ensured by the tabs 78, 80.

[0072] FIG. 12a to 12c shows an example of the transmission device 72 with reference to the second drive pinion 50b, the associated coupling gear 76b and the second drive wheel 74b provided therefor. This depiction equally applies to all three drive wheels 74a, 74b, 74c, coupling gears 76a, 76b, 76c, and drive pinions 50a, 50b, 50c.

[0073] Here the drive wheels 74a, 74b, 74c are arranged on a rotary axis fixed to a bending head 22, i.e., around the pipe penetration 28. By positioning the tool holder 24, the drive pinions 50a, 50b, 50c are moved by means of the slides 64, 66 (not shown in FIG. 12a-12c) in the X and Y direction. By means of the space tabs 78, 80 (also not shown in FIG. 12a-12c), the distances L, L2 between the gears remain unchanged. Consequently as shown in FIG. 12a to 12c, the drive pinion 50b can be variably positioned in the X and Y direction relative to the fixed drive wheel 74b, wherein the coupling gear 76b then assumes in each case an appropriate intermediate position so that engagement is consistently ensured.

[0074] Independent of the X/Y position of the drive pinion 50b, coupling is always retained so that a rotating drive by the drive wheel 74b, and correspondingly the precise establishment of the rotary position of the drive pinion 50b, remain ensured in each position.

[0075] However, an altered angular relationship of the two gears relative to each other results by displacing the drive pinion 50b relative to the drive wheel 74b. This depends on the angle between the axes in each case formed by the coupling gear 76b with the drive wheel 74b and the drive pinion 50b. Based on the design parameters of the gears, i.e., their respective radius and number of teeth, a correction, or respectively compensation angle , can accordingly be calculated or determined by experiments for each X/Y displacement of the drive pinion 50b by which the drive wheel 74b can be rotated in order to achieve a fixed rotary position of the drive pinion 50b despite the displacement. The respective correction, or respectively compensation angle can be considered a term to be subtracted in the activation, i.e., if rotation is desired in the displacement and not a fixed rotary position of the drive pinion 50b, the compensation angle can be subtracted from the rotary angle to be specified.

[0076] The activation and hence the precise positioning and movement of the bending tool 26 relative to the pipe 20 is effectuated by the motor drives 13a-13g already mentioned. These are always position-controlled electric motors which are activated by a central control device 82 as schematically portrayed in FIG. 13.

[0077] A first motor drive 13a serves to move the bending tower 14 in the longitudinal direction, such as by a worm drive or rack and pinion drive (not shown).

[0078] As can be seen in particular in FIG. 3, the motor drives 13b to 13g are arranged on the rear of the bending tower 14. They are each coupled by belts to a number of drive disks 84 arranged axially adjacent to each other.

[0079] As can be seen in FIGS. 9 and 11, the drive disks 84 are rotatably arranged about the pipe penetration 28 and hence the longitudinal axis L of a pipe 20 accommodated therein. As can be seen in FIG. 9, each of the individual drive disks 84 coupled to the motor drives 13b to 13g is coupled to associated drive wheels 74 of the positioning device 62 by one hollow shaft 86 penetrating the head plate 60. In this manner, the controllable motor drives 13b to 13g can drive and specify the rotary position to the drive wheels 74.

[0080] In so doing, the head plate 60 of the bending head 22 is directly coupled to a first drive disk to thereby enable a controlled rotation of the head plate 60 and the entire positioning device 62 fastened thereto with the housing 40 about the longitudinal axis L. The second motor drive 13b schematically portrayed in FIG. 13 accordingly causes the entire bending head 22, and hence also the bending tool 26 arranged on the tool holder 25, to rotate by the coupling that is also only schematically portrayed in FIG. 13.

[0081] With the third and fourth motor drive 13c, 13d, the lift and offset movements of the slides 64, 66 of the positioning device 62 are controlled by rack and pinion drives as already explained in association with FIG. 10. Accordingly, the X/Y position of the bending tool 26 can be specified.

[0082] With the fifth, sixth and seventh motor drive 13e to 13g, three drive gears 74a, 74b, 74c of the positioning device 62 are activated by a belt coupling, drive disks 84 and hollow shafts 83 as described. These are coupled by the coupling device 72 to the three drive pinions 50a, 50b, 50c at the end of the tool holder 24 as explained in association with FIG. 12a bis 12c. Accordingly the rotary movement of the radius roller 30 can be specified by the fifth motor drive 13e, the pivot movement of the sliding block 32 can be specified by the sixth motor drive 13f, and the pivot movement of the counter holder 34 can be specified by the seventh motor drive 13g.

[0083] Accordingly, by activating the motor drives 13a to 13g, the control device 82 can control all the movements of the bending tower 14, bending head 22 and bending tool 26 to assume a respective desired bending position, to position the bending tool 26 there in the desired alignment relative to the pipe 20 and finally to generate the desired bend by activating the bending tool 26.

[0084] The lift and offset movements that can be specified by activating the drives 13c and 13d can on the one hand serve to position the bending tool 26 relative to the pipe 20 so that an appropriate pair of the various grooves 36, 38 of the bending tool is brought into contact with the pipe 20. On the other hand by specifying a path of travel in the X/Y direction, a change of the contact side of the radius roller 30, sliding block 32 and counter holder 34 can be achieved to switch the bending direction to, for example, switch from bending to the right to bending to the left. An activation sequence that is suitable for this could for example first specify a lift in the negative Y direction to remove the bending tool 26 from the pipe 20, then a displacement movement in the X direction to bring the bending tool 26 to the other side of the pipe, and finally a lifting movement in the positive Y direction in order to move the bending tool on the opposite side up to the pipe 20. At the same time, it is always useful to position the sliding block 32 and counter holder 34 in neutral positions during these movements so that the bending tool 26 can be freely positioned on the pipe 20. When specifying the activations for the motor drives 13e to 13g, the control device 82 takes into account the compensation angle to be calculated from the X/Y displacement position.

[0085] The described design of the pipe bending machine 10 depicted in the drawings with the embodiment of the bending tower 14, clamping device 12, bending head 22, positioning device 62 and bending tool 26 shown in the drawings and described above, is accordingly suitable for generating highly complex bending geometries, even for pipelines that for example have sections with different diameters, flexible hose sections, connecting pieces and other special features.

[0086] Changes are also possible in comparison to the depicted and described embodiments. In particular, the bending tool 26 can also have more or fewer movable elements instead of three movable parts (counter holder 34, sliding block 32, radius roller 30). The number of tool drive shafts in the tool holder 24 would then also need to be adapted as well as the number of coupling devices 72 and drive devices therefor. Likewise, the positioning device 62 could be simplified when only one displacement in a single direction is needed instead of the movement in the X and Y directions.

[0087] Moreover, the arrangement of the motor drives 13 b-g on the rear of the bending tower 14 and the transmission of the drive movement via drive disks 84 and hollow shafts 86 are preferred; nonetheless, this can also be achieved differently in alternative embodiments.