The invention relates to a lifting bellows, for example for axle-lifting apparatuses of vehicles.

Lifting bellows made from elastomer material are known per se and are in use. They are used in machine or foundation supports to compensate height differences or in vehicles, especially commercial vehicles, to lift axles which are sometimes not required.

Lifting bellows according to the prior art are generally either designed as rolling bellows, similar to a rolling bellows air spring, or often as a concertina bellows with one or more folds.

DE 88 16 538 U1 discloses an axle-lifting apparatus in which the lifting bellows is disclosed in both embodiments.

The embodiments mentioned are both relatively complex since, on the one hand, a large number of components, such as flange plates or rolling contact pistons are necessary and, on the other hand, the production of the bellows themselves is expensive since bead cores made of metal are generally required in production and these have to be made available separately and inserted into the molds during production. Moreover, the lifting bellows mentioned are quite heavy.

The invention is based on the object of creating a lifting bellows which is lightweight and of simple construction and which can be produced inexpensively.

This object is achieved by virtue of the fact that the lifting bellows has at least one hose-shaped elastomer main body with an elastomer matrix and has reinforcing supports embedded in the elastomer matrix, two end covers and two clamping elements, wherein the reinforcing support of the main body is built up from at least two thread plies, wherein each thread ply is arranged, in the non-loaded state, at a winding angle with respect to the circumferential direction, the absolute value of which winding angle is less than 35.3°, wherein the two winding angles have virtually the same absolute value but different signs, and that the end covers are each connected at both ends to the main body in an air-tight fashion by means of the clamping elements.

Since the winding angles of the thread plies each have the same absolute value but a different sign, a thread angle between the two thread plies which is twice the absolute value of the respective winding angle is obtained from this in the finished bellows. Accordingly, the absolute value of the thread angle according to the invention is 2×35.3° in this case. Thus, the thread angle has an absolute value of less than 70.6°.

If a bellows of this kind with a winding angle of 35.3° is supplied with compressed air, the forces which act on the ends are in balance with the forces which are absorbed by the bellows wall and there is an equilibrium of forces. This is therefore the neutral angle which a corresponding bellows will tend to adopt under internal pressure. If the winding angle of the non-loaded bellows is less than 35.3°, the bellows will consequently have to stretch to achieve this angle.

A bellows of this kind is therefore suitable for lifting loads. Since only a small number of simple components that are easy to produce is required, a lifting bellows of this kind can be produced inexpensively and has only a relatively low weight.

In a development of the invention, the absolute value of the winding angle has a value of less than 27.5°.

In a development of the invention, the absolute value of the winding angle has a value of less than or equal to 20°.

The smaller the winding angle and hence the thread angle, the greater will be the extension of the lifting bellows under load. Thus, even longer lifting travels can be achieved.

