KRAN

Abstract

The invention relates to a crane, in particular to a mobile crane, comprising a lattice boom, a derrick boom, and a boom guying led from the derrick boom to the boom tip, wherein at least one guying frame is provided that is fastened to the boom between the derrick boom and the boom tip and is connected to the boom guying.

Claims

1. A crane comprising a lattice boom, a derrick boom, and a boom guying guided from the derrick boom to the boom tip, wherein at least one guying frame is fastened to the lattice boom between the derrick boom and the boom tip and is connected to the boom guying; and wherein the boom guying frame can transmit compressive forces and/or transverse forces to apply a compressive force and/or transverse force to the boom over the guying during crane operation.

2. The crane in accordance with claim 1, wherein the at least one guying frame comprises at least two side elements connected to one another.

3. The crane in accordance with claim 1, wherein the at least one guying frame is constructed in a spatial lattice design from fiber composite materials.

4. The crane in accordance with claim 1, wherein the guying frame is designed as rectangular or V-shaped or trapezoidal.

5. The crane in accordance with claim 1, wherein the at least one guying frame is supported at the lattice boom pivotable about a pivot axis perpendicular to the longitudinal boom axis or is fixedly connected to the lattice boom.

6. The crane in accordance with claim 1, wherein the guying is supported or guided movably at the guying frame.

7. The crane in accordance with claim 1, wherein the at least one guying frame is attached in the middle boom region.

8. The crane in accordance with claim 1, wherein exactly one guying frame is arranged at the lattice boom so that the remaining main boom length from the topmost guying frame up to the boom tip amounts to approximately a third of the total main boom length.

9. The crane in accordance with claim 1, wherein the guying represents the luffing drive of the crane.

10. The crane in accordance with claim 1, wherein the guying frame is suitable to take up the tensile forces acting on the boom system.

11. The crane in accordance with claim 1, wherein the length of the at least one guying frame is adjustable, ideally during crane operation.

12. The crane of claim 1, wherein the boom guying frame transmits compressive forces to the boom over the guying during crane operation.

13. The crane of claim 1, wherein the construction of the boom guying frame transmits transverse forces to the boom over the guying during crane operation.

14. The crane of claim 4, wherein the guying frame spreads the guying.

15. The crane in accordance with claim 1, wherein the guying is rigidly connected to the guying frame.

16. The crane in accordance with claim 1, wherein a plurality of frames are arranged behind one another at the boom system so that the remaining main boom length from the topmost guying frame up to the boom tip amounts to approximately a third of the total main boom length.

17. The crane in accordance with claim 1, wherein the length of the at least one guying frame is adjustable during crane operation.

Description

[0019] Further advantages and properties of the invention will be explained in more detail in the following with reference to an embodiment shown in the drawings. There are shown:

[0020] FIGS. 1a, 1b, 1c: a boom system in accordance with the prior art and schematic diagrams to explain the previous operation;

[0021] FIG. 2: a schematic diagram to illustrate transverse forces on the boom;

[0022] FIGS. 3a, 3b: schematic diagrams to illustrate bending moments acting on a conventional boom system:

[0023] FIG. 4: a representation of the boom system of the crane in accordance with the invention;

[0024] FIG. 5: a schematic diagram of the crane to represent the mode of action;

[0025] FIG. 6: an alternative embodiment of the guying frame for the crane in accordance with the invention; and

[0026] FIGS. 7a, b: schematic diagrams to further illustrate the operation of the crane in accordance with the invention.

[0027] To reduce the lateral deformation of the boom system decreasing the payload and to reduce the influence of load-induced bending moments, an additional guying frame system has been developed that, unlike previous additional guying systems, can also take up compressive forces and transverse forces. The previous additional guying devices could not do this.

[0028] FIG. 4 shows an embodiment of the invention. The newly developed guying frames 30 comprise two side parts 30a, 30b that are connected to one another. The guying frames are constructed in a spatial lattice construction so that they are suitable for taking up compressive forces and lateral forces. The arrangement of the one or both lattice frames 30 is disposed in this respect in the middle third of the boom 10, i.e. the remaining length of the main boom 10 after the topmost guying frame 30 up to the boom tip 11 amounts to approximately a third of the total main boom length. A guying 20, preferably a double-strand guying. is guided from the derrick boom 40 over the guying frames 30 up to the boom tip 11 and is lashed thereto. The guying 20 can be composed of individual stay poles. The use of a rope arrangement is likewise possible, however. In the crane looked at, the boom guying 20 simultaneously represents the luffing drive that is implemented by an adjustment block 41 at the derrick boom 4 over the stay poles 20.

[0029] The derrick boom 40 is in a predefined position in crane operation. On the luffing of the main boom 10, the rope arrangement of the adjustment block 41 of the derrick boom 40 is retracted or let out. The geometrical relationships between the derrick boom 40, the boom guying 20, the guying frame 30, and the main boom 10 hereby change.

[0030] The connection of the guying frames 30 to the boom 10 is designed as pivotable about a pivot axis perpendicular to the longitudinal boom axis. Alternatively, the guying frames 30 can, however, also be fixedly connected to the boom system 10.

[0031] It is important for the design of the guying 20 that the guying frame or frames 30 hold the guying 20 above the boom 10 wherever possible. This is shown, for example, in FIG. 5 that shows a rear view of the crane system in accordance with the invention. It is ensured due to the guying frame 30 that the guying 20 runs along the rear side of the boom 10 and, unlike in FIG. 2, only differs slightly laterally from the boom back. The transverse forces F.sub.Q introduced by the guying onto the boom system can thereby be reduced and the deformation of the boom system due to transverse forces can be decreased. The stiff side plates 30a, 30b of the guying frame 30 are only very slightly deformed due to the transverse forces.

[0032] In order to additionally increase the effect of the guying frame 30, the latter can also be of V-shaped or trapezoidal construction, as can be seen, for example, from FIG. 6. The spreading of the boom guying 20 is increased by the trapezoidal construction of the guying frame 30 of FIG. 6, which additionally increases its effect.

[0033] A further profitable application of the guying frame 30 in accordance with the invention comprises the latter likewise reducing the bending moment MB acting on the boom system 10 during the crane work due to its construction stiff with respect to compression. This applies all the more to steep boom positions.

[0034] As can be seen from FIG. 7, the guying 20 here runs from the derrick boom 40 to the tip 11 of the main boom 10. The boom 10 shown is additionally designed with a fixed lattice tip 13. The guying frame 30 in accordance with the invention is also arranged after approximately two thirds of the main boom length here. As is shown by the arrow direction, a compressive force FD is introduced into the boom 10 by the guying 20, said compressive force counteracting the bending moment MB in the region of the guying frame 30 and considerably reducing the boom deformation. A comparison of FIGS. 3a and 7a shows the positive effect.

[0035] The same result is furthermore produced in a crane to whose main boom 10 a luffable lattice tip 12 or an additional boom connected in an articulated manner is fastened. Bending moments MB occurring in the region of the guying frame 30 can also be substantially compensated here by the introduction of a compressive force FD over the guying frame 30.

[0036] The essential inventive features of the guying 20 in accordance with the invention or of the guying frame 30 will again be given in the following. The guying frame 30 can likewise take up both tensile forces and lateral forces in addition to compressive forces. This is achieved, for example, by a rectangular or trapezoidal or V-shaped construction of the guying frame 30 that is set up as a spatial guying frame from a lattice structure. The boom system can be equipped with a single frame 30 or with a plurality of frames 30 arranged behind one another. The guying frames can furthermore be designed as foldable to vary their angles with respect to the main boom 10. An adaptation of the spreading can also be possible in the spatial design of the guying frame 30 to be able to set the resulting spread of the guying 20.