TECHNICAL FIELD

The present invention relates to a boom arm system, and in particular to a boom arm system for a (mobile) concrete delivery device.

DESCRIPTION OF THE PRIOR ART

As is known, concrete delivery devices comprise a boom arm system which is formed from a plurality of boom arms connected pivotably to one another and in which the individual boom arms come to lie on one another in the folded-in state. The aim here is for the boom arms in their folded-in position to require as little space as possible and for the concrete delivery device to therefore have an overall height which is as low as possible and is in accordance with traffic regulations (cf., for example, DE 10 2008 013 990 A1).

SUMMARY OF THE INVENTION

Proceeding therefrom, a concrete delivery device having the features of claim1is proposed according to the invention.

The basic concept of the invention consists in inserting one boom arm in the folded-in position into a recess formed in another, for example adjacently lying boom arm, in order to reduce the overall height. The clear size of the recess is somewhat wider than the width of the boom arm to be inserted into the recess.

This makes it possible to save construction space and a design of the folded arm package that is more effective in terms of construction space is made possible. Since the geometrical moment of inertia and the moment of resistance depend primarily on the height of the girder forming the boom arm, the arms can thus be designed to be lighter while having the same load-bearing capacity.

For the configuration according to the invention of a boom arm system, boom arms manufactured in particular from composite material are appropriate. Typical composite materials are, for example, carbon-fibre-reinforced plastics which are also known by the abbreviation CFRP (carbon-fibre-reinforced plastic). It is in principle also possible to realize the boom arm system according to the invention with boom arms made from steel, but steel has rather a tendency to be geometrically unstable while higher wall thicknesses (with the same or lower weight) can be realized with CFRP structures. In addition, sandwich structures can be constructed relatively simply. It is also possible in the case of CFRP boom arms to adapt the wall thicknesses of the girder to the loading; for example, the limbs (side walls) can be designed to be more solid than the rest of the arm. Suitable composite materials include in particular (but not exclusively) fibre composite materials, such as the CFRP already mentioned, or else containing basalt fibres, aramid fibres, glass fibres or the like.

The boom arm system can comprise boom arms composed of steel and boom arms composed of composite material or else of a composite mix (such as, for example, upper side of steel and the lower side of fibre composite material), or all of the boom arms can be made from composite material.

The recess can extend substantially over the entire length of the other boom arm. Accordingly, the boom arm can be inserted into the other boom arm over substantially the entire length of the boom arm, for example with the swivel joint arrangements being left free. The boom arm can be inserted over part of its height or substantially the entire height. If two adjacent boom arms have recesses according to the invention, the boom arm can in each case lie proportionally with part of its height in the two recesses in such a manner that it is substantially completely accommodated by the two recesses.

Further advantages and refinements of the invention emerge from the dependent claims, the description and the attached drawing.

It goes without saying that the features mentioned above and those which have yet to be explained below can be used not only in the respectively stated combination, but also in other combinations or on their own without departing from the scope of the present invention.

The invention is illustrated schematically in the drawing with reference to an exemplary embodiment and will be described in detail below with reference to the drawing.

