APPARATUS AND METHOD FOR BENDING TUBULAR OR ROD-SHAPED MATERIAL

Abstract: Bending apparatus in which tubular or rod-shaped material (1) is bent with the aid of a rigidly mounted roller (11) and a freely movable roller (12), which consists of only one roll. The roll may be translated in two mutually orthogonal directions and moreover may be rotated round an axis that is substantially aligned to a principal axis of the material (1) to be processed.

Description: Apparatus and method for bending tubular or rod-shaped material The invention relates to an apparatus for bending tubular or rod-shaped material, comprising a bending head provided with at least one rigidly mounted roller and one movable roller and a conveying element for conveying the material to be machined along its principal axis to the head. An apparatus of this type is known in the art. The known apparatus is normally referred to as a bending apparatus, in which the material is pulled around a mandrel until a predetermined bending angle is realized, after which the operation can be repeated, possibly after translating and rotating the material along and around a principal axis of the material. In this manner complex products can be realized, like hand rails for a staircase, exhausts for motor cars and the like. The only requirement the product to be made has to meet is that it consists of a number of discrete and mutually separated bends. Opposite to the known apparatus the inventive apparatus is capable of making a continuous and freely programmable curvature and is according to an aspect of the invention characterized in that the movable roller is provided with suspension means and steering means for enabling it to translate in a first translation direction, to translate in a second translation direction and to rotate around a rotation axis. A favourable embodiment according to another aspect of the invention is characterized in that the first and the second translation direction are chosen at least substantially perpendicular to the principal axis. By combining these two movements, it is possible to force the material into any direction at any moment. As usual in the art, the movable roller is provided with a groove which supports the material. This prevents tubular material from collapsing and minimises damage to the material. A favourable embodiment according to another aspect of the invention, in which the material remains pushed into the groove during the entire bending operation, is characterized in that the rotation axis is chosen at least substantially parallel to the principal axis. As it is possible now to keep the material pushed into the groove, a favourable embodiment according to another aspect of the invention is characterized in that the movable roller comprises only one roll. Although it is possible to realise any shape by merely manipulating the movable roller, it may be of advantage, for example while making two bends that are not situated in one plane, to rotate the tube in a controlled manner. A favourable embodiment of the inventive apparatus is thereto characterized in that the conveying element is moreover arranged for rotating the material round its principal axis. According to another aspect of the invention, three possible movements of the movable roller are freely programmable. The apparatus is thereto characterized in that the steering element is provided with three motors for realising the translations and the rotation of the movable roller . In order to guarantee a maximum degree of freedom to the movable roller the apparatus is according to another aspect of the invention characterized in that the suspension means of the movable roller comprises a spherical bearing. Connected to the spherical bearing is an arm to which the three motors are coupled, while the movable roller is coupled to an arm connected to the opposite side of the spherical bearing. Although it is in principle possible to realise any shape by merely using the roller and the steering element it may be of advantage, for example while processing thin-walled tube that may collapse easily, to support axial movements of the tube to be processed near the movable roller. According to another aspect, the invention is thereto characterized in that the rigidly mounted roller is provided with drive means for supporting axial movements made by the conveying element. The invention also relates to a method for bending tubular or rod-shaped material with a bending head, during which a conveying element conveys the material to be bent along its principal axis towards the bending head, and a rigidly mounted roller supports and clamps the material while a movable roller performs the actual bending action. According to another aspect the invention is characterized in that the movable roller is placed before the rigidly mounted roller and is translated and rotated such that the material fed towards the head obtains the desired curvature . A favourable realisation of the method is according to another aspect of the invention characterized in that the conveying element may rotate the material to be bent round its principal axis in order to support the movements of the movable roller. The invention will be further explained with reference to the following figures, in which: Fig. 1 schematically represents, in top view, a possible embodiment of the bending apparatus; Fig. 2 schematically represents, in top view, a possible embodiment of the bending head; Fig. 3 schematically represents, in side view, a possible embodiment of the steering element. Fig. 1 schematically represents, in top view, a possible embodiment of the bending apparatus, where the material 1 to be processed is conveyed with the aid of a conveying element 2 to a bending head 3. Conveying element 2 comprises a slide 4, which may run along a bed 5, which bed 5 is mounted onto a frame 6. Conveying element 2 further comprises a clamp, not shown in Fig. 1 and well-known in the art, for clamping the material 1 to be processed, a first motor 7, for moving slide 4 towards bending head 3, a second motor 8, for rotating the material 1 to be processed together with the clamp round its principal axis, a first measuring instrument 9, for measuring the movement of the slide and a second measuring instrument 10, for measuring the rotation of the material to be processed. First measuring instrument 9 and second measuring instrument 10 are electromagnetic transducers, well-known in the art or electro-optical transducers integrated into slide 4. Measuring instrument 9 and second measuring instrument 10 determine the tolerances in the final product as produced by the apparatus. Bending head 3 consists of a rigidly mounted roller 11 and a movable roller 12. Movable roller 12 is connected, via an arm 13 and suspension means 14 to a steering element 15, which may be steered such that movable roller 12 may translate in the plane of the drawing, perpendicular to the plane of the drawing, can rotate round arm 13 and moreover can perform linear combinations of these movements. By moving movable roller 12 in a suitable manner, while at the same time element 4 conveys the material to be processed and, if necessary, rotates it round its principle axis, at least substantial all types of curvatures can be given to the material 1 to be processed. For every product to be developed it is necessary to produce some test specimen, as for example a tube rebounds after bending, dependent on the type of material and the thickness of the wall, but this is in fact true for every type of bending apparatus. Fig. 2 schematically represents, in top view, a possible embodiment of the bending head 3, together with suspension means 14 and steering element 15. Steering element 15 comprises a system of three motors and three spindles, for translating and rotating arm 13, the movements of which are transferred to movable roller 12 via the suspension means 14, which are embodied here as a spherical bearing. Suspension means 14 may of course be embodied as a cardan transmission or as a universal joint. The only thing of importance is that there is substantially no clearance, as this will result in bad tolerances in the final product. Movable roller 12 has in fact only one roll, in which a groove is made, which groove encloses half of the material 1 to be processed. This substantially prevents the material 1 to be processed from buckling or deteriorating otherwise, while for movable roller 12 a large degree of freedom is guaranteed. Rigidly mounted roller 11 consists of four rolls, also provided with grooves, which are dimensioned such that the material 1 to be processed is supported all round yet it still remains possible to rotate the material 1 to be processed round its principal axis. Strictly speaking it is not necessary to drive the four rolls of rigidly mounted roller 11, but in this embodiment the rolls are driven and they are moreover mutually coupled with toothed wheels, mounted below the rolls. The advantage is that the material 1 to be processed deteriorates to a lesser extent and a sudden buckling of for example a thin- walled tube between the conveying element 2 the rigidly mounted roller 11 is prevented. Rigidly mounted roller 11, together with the toothed wheels below it, is built as a group that can easily be removed to be exchanged by another group if another type of material is to be processed. In addition, movable roller 13 is. connected to arm 13 such that it is readily exchanged, for example with one bolt. By exchanging the entire bending head it is possible to mount for example smaller rolls with a smaller centre distance, such that finer material may be processed and that smaller radii may be realized. It is also possible to make a special bending head for special, non-circular material like strip. It is true that the strip-shaped material cannot be rotated within rigidly mounted roller 11, but all bends commonly used in processing strip can be made solely by manipulating movable roller 12. Incidentally, it may be of advantage to provide movable roller 13 with two rolls, notwithstanding the fact that only one roll is actively used in the bending process. This is for example the case if a number of bends must be made to the left and to the right. With one roll this is possible by rotating the material 1 every time 180 degrees with the aid of conveying element 2 or by moving movable roller 12 every time underneath the material 1 to be processed, but time can be saved by using two rolls. Fig. 3 schematically represents, in side view, a possible embodiment of the steering element 15. Steering element 15 comprises three motors 16,17,18, on one side mounted with hinges 19,20,21 to a frame 6, on another side provided with spindles 22,23,24, which spindles cooperate with screw- threaded holes in spherical bearings 25,26,27. With this combination a plate 28 can be translated in a vertical direction by steering motor 16, or translated in a horizontal direction by steering motors 17,18 in the same manner, or rotated around spherical bearing 25 by steering motors 17,18 in an opposite manner. Arm 13 is connected to the centre of plate 28 with the aid of a universal joint, not shown in the figure, such that the translations and the rotation can be exactly followed and passed to movable roller 12 via suspension means 14. Both the universal joint, connected to the centre of plate 28 and the spherical bearing 25 are mounted at the highest possible position within frame 6, as a consequence of which arm 13 runs practically parallel to the material 1 to be processed. This means that the material 1 to be processed is always situated in an optimal fashion in movable roller 12. For spindles 22,23, 24, ball-guided spindles have been chosen, because any clearance here will immediately influence the tolerances of the product.

Claims: Claims 1. Apparatus for bending tubular or rod-shaped material, comprising a bending head provided with at least one rigidly mounted roller and one movable roller and a conveying element for conveying the material to be machined along its principal axis to the head, characterized in that the movable roller is provided with suspension means and steering means for enabling it to translate in a first translation direction, to translate in a second translation direction and to rotate around a rotation axis. 2. Apparatus according to claim 1, characterized in that the first and the second translation direction are chosen at least substantially perpendicular to the principal axis. 3. Apparatus according to claim 2, characterized in that the rotation axis is chosen at least substantially parallel to the principal axis. 4. Apparatus according to claim 3, characterized in that the movable roller comprises only one roll. 5. Apparatus according to claim 4, characterized in that the conveying element is moreover arranged for rotating the material round its principal axis. 6. Apparatus according to claim 4, characterized in that the steering element is provided with three motors for realising the translations and the rotation of the movable roller . 7. Apparatus according to claim 6, characterized in that the suspension means of the movable roller comprises a spherical bearing. 8. Apparatus according to claim 1, characterized in that the rigidly mounted roller is provided with drive means for supporting axial movements made by the conveying element. 9. Method for bending of tubular or rod-shaped material with a bending head, during which a conveying element conveys the material to be bent along its principal axis towards the bending head, and a rigidly mounted roller supports and clamps the material while a movable roller performs the actual bending action, characterized in that the movable roller is placed before the rigidly mounted roller and is translated and rotated such that the material fed towards the head obtains the desired curvature . 10. Method according to claim 9, characterized in that the conveying element may rotate the material to be bent round its principal axis in order to support the movements of the movable roller.

Inventors: SCHOLTEN JOHANNES THEODORUS, SCHOLTEN, JOHANNES, THEODORUS
Applicants: BUSSCHERS METAALBEDRIJF BV, SCHOLTEN JOHANNES THEODORUS, METAALBEDRIJF BUSSCHERS B.V., SCHOLTEN, JOHANNES, THEODORUS
Application year: 1999
Main classification: B21D7
IPC codes: B21D7