The invention relates to a tube bending apparatus having a feed or advancing arrangement capable of moving rectilinearly in a guide arrangement and acting on one end of the tube, having at least one bending arm which is pivotable about a pivot joint and which comprises clamping elements acting on the other end of the tube, and having a heating arrangement which is situated at the end of the guide arrangement and surrounds the tube at the bending region.
The invention has as its object to provide a bending apparatus which allows alternate bending and setting up at the two sides of the apparatus over large diameter ranges.
To achieve this object, according to the invention a bending apparatus is proposed which is characterised in that at the other end of the guide arrangement there is situated a further heating arrangement, that at least one further bending arm is associated with this heating arrangement, and that the feed arrangement is arranged between the opposite heating arrangements and is constructed to act on one end of a tube at a time in both directions of movement.
The bending apparatus according to the invention achieves a considerable increase in the output of the machine, since already during the bending of one tube a second tube can be inserted at the other side of the feed arrangement in the machine bed and clamped securely in position. After the bending operation is completed, by reversing the feed arrangement and changing-over the energy source to the heating arrangement at the opposite side it is possible to begin at once with the bending of the next time.
An important advantage of the apparatus according to the present invention consists in that by the arrangement of a plurality of bending arms which are designed for various tube dimension ranges and bending radii it is possible to bend tubes in an unusually large range of dimensions on a single bending apparatus. Thus it is possible to bend tubes of dimensions ranging from small to very large both with small and with large bending radii.
The accompanying drawings show in diagrammatic manner possible constructional forms of the bending apparatus according to the present invention.
In the drawings:
FIG. 1 shows an installation in plan view,
FIG. 2 shows an installation with two identical bending arms,
FIG. 3 shows an installation with four bending arms.
In FIG. 1, the bending arm 1 has bent the tube R through 90.degree. about the pivot point 3. The adjustable clamping elements 2 are arranged interchangeably in the bending arm 1. The tube is heated during the bending operation in known manner by the heating arrangement 4. The tube is mounted on the machine bed 20 by adjustably spaced guide rollers 5 and a clamping arrangement 7.
At the opposite side a larger-diameter tube R' is shown during a bending operation. In this case the feed carriage 9 which is capable of moving in both directions for example on chains 6, presses against the clamping arrangement 7'. The tube R' is held by the adjustable clamping elements 2' of the bending arm 1' pivoting about the pivot point 3' and heated after the adjustably spaced guide rollers 5' during a bending operation by the heating apparatus 4'. A control device is provided in the energy source 16 for switching over the supply of energy from the heating arrangement 4 to the heating arrangement 4' and vice versa.
The entire apparatus is capable of moving on rails, the machine bed 20 on rails 21 and the bending arms 1 and/or 1' at their pivot points 3 and/or 3' are adjustably mounted on the rails 8 and 8'.
In FIG. 2 two bending arms 1 and 1' of equal length are shown, the tube R being clamped in position whilst the tube R' has already been bent.
The layout shown in FIG. 3 shows two further bending arms 18 and 19 of different length in addition to the two identical bending arms 1 and 1'.