Bending machine for bending rod-shaped or tubular workpieces

Abstract

A bending machine for elongated workpieces, comprising a bending tool with a bending head having a bending disc with a bending groove and two slide rails, each having a molding groove and which can be placed laterally against opposing sides of the workpiece. Each slide rail is secured to a support part and laterally supports the workpiece from where the workpiece is fed into the bending groove to a point in front of the bending groove when the slide rail is resting against the workpiece. Each support part is adjustable between a starting position, in which the slide rail does not rest against the workpiece, and a final position, in which the slide rail contacts the workpiece. Upon contacting the workpiece, the other slide rail assumes its starting position. The support parts are attached to a two-arm lever, and a slide piece rests against the workpiece in each lever position.

Claims

1. A bending machine for bending rod-shaped or tubular workpieces, comprising: a bending tool which includes a bending head with a bending disk, the bending disk comprising at least one circumferential bending groove extending around an axis, wherein the bending disk is configured to receive the workpiece in the bending groove selectively either on a first side of the axis or on a second side of the axis, and the bending tool further comprising a first slide rail and a second slide rail, each of which first and second slide rails has a molding groove which is configured to be placed laterally against opposing longitudinal sides of the workpiece, and a pivotably mounted, two-armed lever which is pivotable between a first pivot position and a second pivot position, wherein the first slide rail is secured to a first support part and the second slide rail is secured to a second support part, with the two support parts being mounted mirror-inverted to one another at ends of the two-arm lever, wherein each slide rail is configured to laterally support the workpiece, and is adjustable between a starting position, in which the slide rail does not rest against the workpiece, and an engagement position, in which the slide rail contacts the workpiece, wherein, in the first pivot position of the lever, the first slide rail is in the engagement position and rests laterally against the workpiece received in the bending groove on the first side of the axis and, in the second pivot position of the lever, the second slide rail is in the engagement position and rests laterally against the workpiece received in the bending groove on the second side of the axis.

2. The bending machine as claimed in claim 1, wherein the pivotably mounted lever is mounted between a workpiece guide on a machine frame and the bending tool.

3. The bending machine as claimed in claim 1, wherein the lever is pivotably mounted on a bracket which is fastened to the machine housing.

4. The bending machine as claimed in claim 1, wherein the lever is fastened to the bending head in a way that allows pivoting and horizontal movement.

5. The bending machine as claimed in claim 1, wherein the two-arm lever is V-shaped or C-shaped.

6. The bending machine as claimed in claim 1, wherein the slide rails are set at an angle of 60° to one another.

7. The bending machine as claimed in claim 1, wherein each slide rail is configured to be moved on the associated support part in parallel to the longitudinal direction of the workpiece.

8. The bending machine as claimed in claim 1, further comprising a servo motor for pivoting the lever between the first and second pivot positions.

9. The bending machine as claimed in claim 1, wherein each slide rail is seated on a tool holder which is attached to the associated support part and which in turn is configured to be moved in parallel to a longitudinal direction of the workpiece via a linear guide.

10. The bending machine as claimed in claim 9, further comprising an adjustable stop on each linear guide for defining an end position of the associated slide rail.

11. The bending machine as claimed in claim 10, wherein each slide rail is spring-reloaded in a direction of the adjustable stop.

12. The bending machine as claimed in claim 1, wherein the bending head is configured to be moved laterally and/or vertically relative to a machine frame.

13. The bending machine as claimed in claim 1, further comprising a gripper guide workpiece feeding.

14. The bending machine of claim 1, wherein the slide rails are set at an angle of 90° to one another.

15. The bending machine as claimed in claim 1, wherein the bending disk is located between ends of the pivotably mounted lever.

16. The bending machine as claimed in claim 1, wherein each slide rail is configured to laterally support the workpiece, when the slide rail is resting against the workpiece, in a region between a first point where the workpiece is tangentially fed into the bending groove of the bending disk and a second point located in a specified distance in front of the first point.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in more detail below in principle by way of example on the basis of the drawings.

(2) FIG. 1 shows a perspective view of a pipe bending machine according to the invention with pipe gripper guide, wherein a bending unit with bending head and with slide rails attached to a pivotable lever is arranged at the front end of the machine frame;

(3) FIG. 2 shows a view from a diagonal perspective (from above) of the pivotable lever device for the slide rails with a bracket for attachment to the machine frame;

(4) FIGS. 3 to 5 show representations of different positions of the lever device carrying the slide rails as they are (or can be) approached during the working cycle of the bending machine;

(5) FIG. 3a in front view and FIG. 3b in plan view show a bending machine according to the invention in a position for left bending;

(6) FIG. 4a in front view and FIG. 4b in plan view show a bending machine according to the invention, in which the two-arm lever carrying the slide rails is in a central position in which no slide rail rests against the workpiece to be processed, and

(7) FIG. 5a in front view and FIG. 5b in plan view show a bending machine according to the invention in a position for right bending.

DETAILED DESCRIPTION

(8) The following figure description shows an embodiment of a pipe bending machine as claimed in this invention, wherein the same numerals are used for the same parts in different figures.

(9) FIG. 1 shows a perspective view (from the front and from diagonally above) of a pipe bending machine 1 with a machine frame 2, on the side of which a switch cabinet 3 with a control panel 4 and a screen 5 for operating the pipe bending machine 1 is mounted.

(10) A spindle arrangement 6 with a protective hood 7 is assigned to the machine frame 2, wherein a pipe gripper 8 is provided here for holding and feeding as well as for rotating a cut-to-length workpiece 9 (pipe) about its longitudinal axis.

(11) Furthermore, a bending unit 10 with a bending head 11 is attached to the front end face of the machine frame 2, wherein the bending unit 10 is movable both in a vertical (Z-axis) and perpendicular (B-axis) direction to the direction of movement of the workpiece 9 (the directions of movement are shown in FIG. 1 by the arrows associated with the bending unit 10).

(12) In the embodiment shown here, a pivotable lever device 12 is attached to the machine frame 2, which device is shown in more detail in a perspective view in FIG. 2:

(13) This lever device 12 is substantially formed by a two-arm lever 13, which is attached to a bracket 18 such that it is pivotable via a bearing pin 19, the pivot point of which also represents the pivoting axis for the lever 13. As FIG. 2 shows, the lever 13 is located at the front of the bracket 18, at the rear of which the two-arm lever 13 is connected via a gearbox to a servomotor 20, via which the drive for the pivoting movements of the lever 13 is generated.

(14) The lever 13 has a lever arm 16 on one side (shown on the left in FIG. 2) for left bending and a lever arm 17 on its other side for right bending.

(15) At the end of the lever arm 16 for left bending, a support part 22 is formed and at the end of the lever arm 17 for right bending, a support part 23 is formed, to which in each case a linear guide 25 or 26 is fastened, in which in each case a displaceable tool holder 15 is located, to which a slide rail 14 is fastened via a clamp 21.

(16) The movement of the tool holders 15 in the linear guides 25 and 26 and thus the movement of the slide rails 14 takes place in a direction parallel to the longitudinal direction of the workpiece 9 to be processed.

(17) The linear guides 25 and 26 each have an adjustable stop 27 and 28 respectively, which in the exemplary embodiment shown is mounted in the form of a rotatable nut and by means of which the starting position of the slide rail 14 of the respective lever arm 16 and 17 can be adjusted. Such a positioning is necessary because the slide rail 14 must be adapted to the position of the workpiece 9 to be bent in accordance with the bending step to be carried out. In addition, this function is essential if a cut-to-length pipe is to be bent which has already been processed at its end (e.g. an end reshaping or a fitted nut) and the inner contour of the slide rail 14 has a certain shape (groove, slot, etc.). Due to the frictional force that occurs when the slide rail 14 contacts the workpiece 9, the slide rail 14 is pulled along by the workpiece 9 during the corresponding bending step until the bending is complete, after which the slide rail 14 must be returned to its starting position again. Such a return to the starting position can be achieved by the slide rail 14, as shown in FIG. 2 for instance, using suitable preloading springs 29, but could also be suitably controlled pneumatically or electrically. The entire lever device 12 with the individual elements attached to it represents an assembly which could also be described as a pivotable support device or as a counterholder unit.

(18) FIGS. 3a, 3b, 4a, 4b as well as 5a and 5b show the bending machine 1 according to the invention in different positions of the lever device 12, which can or must be approached during a working cycle of the bending machine 1.

(19) Thus FIG. 3a shows a front view of a pipe bending machine 1 and FIG. 3b a plan view of the latter in a position which is intended for left bending, wherein in both figures (as also in the following figures) the workpiece is not shown.

(20) The workpiece is fed to the bending unit 10 via the feed, such as a pipe gripper feed, and threaded between a clamping jaw 30 and the bending mold 31 and clamped in place by these. The lever device 12 then pivots up to the right (seen in the longitudinal direction of the workpiece 9 to be processed), cf. FIG. 3a, and the slide rail 14 of the lever arm 16 for left bending is in contact with the workpiece. During the subsequent bending process, the lever device 12 serves as the corresponding support device or counterholder unit for the workpiece to be processed. As already mentioned, the friction force pulls the slide rail 14 along with the forward moving workpiece 9 until the bend is completed. Then, when the slide rail 14 is lifted off the side of the workpiece 9, the support part 22 holding the slide rail 14 is pushed back again into its starting position via the preloaded spring 29.

(21) It should be noted here that on each slide rail 14, on its side facing the workpiece 9, a molding groove 24 is mounted, which runs parallel to the longitudinal direction of the workpiece 9 and, when the slide rail 14 rests against the side of the workpiece 9 to be supported, comes into contact with its outer circumference. Similarly, at least one (in the figures: two) bending groove 32 is also mounted on to the bending mold 31.

(22) In the illustrations in FIGS. 4a and 4b, the lever device 12, viewed in the feed direction of the workpiece 9, has been pivoted clockwise and assumes a central position in which neither of the two lateral slide rails 14 comes into lateral contact with a workpiece 9.

(23) This central position, as shown in FIGS. 4a and 4b, is crossed when changing from right bending to left bending (or vice versa). It is also essential for making a final bend on the workpiece 9 to the extent that short straight lines at the end can be produced as a result. When the lever 13 is in this central position, the workpiece 9 held by a pipe gripper 8, for example, can be moved forward from the latter into the tool area and picked up and held there between the clamping jaws 30 and the bending mold 31. The pipe gripper 8 then moves back without the workpiece 9, after which the slide rail 14 is placed on the side of the workpiece and the last bend is initiated.

(24) FIG. 5a shows the bending machine 1 in the position for right bending from the front and FIG. 5b shows a plan view of the lever device 12 (supporting device) in this position.

(25) If a change is to be made from a position for left bending to the position for right bending, the bending head 11 is lowered vertically downward, then moved transversely to the longitudinal direction of the workpiece 9 and then repositioned in its new working position as shown in FIGS. 5a and 5b. The bending head 11 is moved vertically downward depending on the central axis of the workpiece 9. The lever device 12 or supporting device pivots clockwise from right to left, as seen in the feed direction of the workpiece 9, until the end position shown in FIGS. 5a and 5b is reached, in which the slide rail 14 held on the lever arm 17 for right bending can be placed laterally on the workpiece 9 and is carried along with it during the feed of the latter for carrying out the bending by friction in the transport direction, so that the support by this slide rail 14 is always realized over an equal distance on the workpiece 9.

(26) In the exemplary embodiments shown, the arrangement of the slide rails 14 is such that they are set at an angle of 60° to each other. This angle is particularly advantageous because, on the one hand, only a relatively short distance must be covered in order to pivot from right to left bending, which can lead to a considerable reduction in non-productive times. On the other hand, however, the lever arms 16 and 17 are still sufficiently far apart at this angle to guarantee a very large bending clearance. However, a different size of the relative angle of attack of the two slide rails 14 to each other would indeed also be possible, for instance larger or smaller than 90°.

(27) The shape of the two-arm lever 13 can be designed in any suitable way, e.g. V-shaped or C-shaped (the latter being shown in the figures).

(28) The design of the lever device 12 according to the invention can particularly also be used advantageously for thin-walled pipes, which can also be bent without an internal mandrel. This lever device 12 can also be used to bend aluminum pipes and stainless-steel pipes without cold welding.

(29) The bending quality is increased compared with conventional bending systems, while at the same time the unwanted non-productive times are reduced.