Method of raising a crane boom

Abstract

The invention relates to a method of raising a telescopic boom of a mobile crane having a luffing fly jib and having a spatial boom guying. To be able to raise particularly long luffing fly jib systems together with the telescopic boom here, in accordance with the invention the telescopic boom is first telescoped outwardly to its desired length. In this position, all the telescopic sections are bolted to one another and the spatial guying is tensioned before the raising of the luffing fly jib pivotally connected to the telescopic boom.

Claims

1. A method of raising a telescopic boom of a mobile crane having a luffing fly jib and having spatial boom guying, wherein the telescopic boom includes telescoping sections and is first telescoped outwardly to a desired length of the telescopic boom, all the telescopic sections are bolted to one another in this position and the spatial boom guying is tensioned before the luffing fly jib pivotally connected to the telescopic boom is raised, wherein the spatial boom guying is Y-shaped guying connected to the telescopic boom and extending laterally outward therefrom out of a plane of the luffing movement.

2. A method in accordance with claim 1, wherein the telescopic boom is installed together with the spatial boom guying, ready for operation, but not tensioned, in an approximately horizontal position before the outward telescoping.

3. A method in accordance with claim 2, wherein the luffing fly jib is pivotably bolted to the telescopic boom in almost horizontal position and movably supported on at least a first carriage at a free end of an outer part of the luffing fly jib.

4. A method in accordance with claim 3, wherein the main boom is positioned steeply and telescoped outwardly to a desired position so that the pivotally connected first end of the luffing fly jib is raised and an outer end of the luffing fly jib rolls freely on the first carriage.

5. A method in accordance with claim 4, wherein the luffing fly jib is made in multiple parts, with a kinking of the parts with respect to one another being made possible in a region of a connection point of the luffing fly jib parts.

6. A method in accordance with claim 5, wherein a releasable second carriage is arranged in a region of the kink point of the luffing fly jib before the raising.

7. A method in accordance with claim 3, wherein the luffing fly jib is made in multiple parts, with a kinking of the parts with respect to one another being made possible in a region of a connection point of the luffing fly jib parts.

8. A method in accordance with claim 7, wherein a releasable second carriage is arranged in a region of the kink point of the luffing fly jib before the raising.

9. A method in accordance with claim 2, wherein the luffing fly jib is made in multiple parts, with a kinking of the parts with respect to one another being made possible in a region of a connection point of the luffing fly jib parts.

10. A method in accordance with claim 1, wherein the luffing fly jib is pivotably bolted to the telescopic boom in almost horizontal position, and movably supported on at least a first carriage at a free end of the outer part of the luffing fly jib.

11. A method in accordance with claim 10, wherein the main boom is positioned steeply and telescoped outwardly to a desired position so that the pivotally connected first end of the luffing fly jib is raised, and an outer part of the luffing fly jib rolls freely on the first carriage.

12. A method in accordance with claim 11, wherein the luffing fly jib is made in multiple parts, with a kinking of the parts with respect to one another being made possible in a region of a connection point of the luffing fly jib parts.

13. A method in accordance with claim 12, wherein a releasable second carriage is arranged in a region of the kink point of the luffing fly jib before the raising.

14. A method in accordance with claim 10, wherein the luffing fly jib is made in multiple parts, with a kinking of the parts at a kink point with respect to one another being made possible in a region of a connection point of the luffing fly jib parts.

15. A method in accordance with claim 14, wherein a releasable second carriage is arranged in a region of the kink point of the luffing fly jib before the raising.

16. A method in accordance with claim 10, wherein the luffing fly jib is made in multiple parts, with a kinking of the parts with respect to one another being made possible in a region of a connection point of the luffing fly jib parts.

17. A method in accordance with claim 16, wherein a releasable second carriage is arranged in a region of the kink point of the luffing fly jib before the raising.

18. A method in accordance with claim 1, wherein an auxiliary rope which runs off from an auxiliary winch and is loaded with a defined tension by the auxiliary winch, is connected to the hoist rope during the raising.

19. The method in accordance with claim 18 wherein the auxiliary winch is arranged on a superstructure of the mobile crane.

20. A method of raising a telescopic boom of a mobile crane having a luffing fly jib and having spatial boom guying, wherein the telescopic boom includes telescoping sections is first raised by means of a luffing cylinder and telescoped outwardly to a desired length of the telescopic boom, all the telescopic sections are bolted to one another in this position and the spatial boom guying is tensioned before the luffing fly jib pivotally connected to the telescopic boom is raised, wherein the spatial boom guying is Y-shaped guying out of a plane of the luffing movement.

21. A method in accordance with claim 20, wherein the luffing fly jib is pivotably bolted to the telescopic boom in almost horizontal position, and movably supported on at least a first carriage at a free end of the outer part of the luffing fly jib.

22. A method in accordance with claim 20, wherein the luffing fly jib includes an inner part and an outer part wherein a first end of the inner part is pivotably bolted to the telescopic boom in almost horizontal position and a second end of the inner part is pivotally connected to the outer part at a kink point, the outer part of the luffing fly jib is movably supported on at least a first carriage at a free end of the outer part of the luffing fly jib and the luffing fly jib is movably supported on a releasable second carriage in the vicinity of the kink point.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further details and advantages of the invention will be explained in more detail with reference to the embodiments shown in the drawing. There are shown:

(2) FIG. 1: a schematic representation of a boom in accordance with the prior art;

(3) FIG. 2: a schematic representation of a boom to illustrate the method in accordance with the invention;

(4) FIGS. 3a-3e: a mobile crane with a telescopic boom in different installation positions; and

(5) FIG. 4: a mobile crane with a telescopic boom in which the hoist rope is tensioned with an auxiliary rope during installation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) The raising method in accordance with the invention will be described in the following with reference to FIGS. 2 and 3. First, as shown in FIG. 3a, the telescopic boom 10 is installed in an approximately horizontal position on the mobile crane 5. At the same time, the spatial guying 22 is raised, but not yet tensioned at this time. The telescopic boom 10 is completely retracted here. In the representation in accordance with FIG. 3, an adapter 24 which is counted as part of the main boom is additionally fixedly connected to the telescopic boom 10. Likewise still shown in FIG. 3a, a luffing fly jib 12 is installed and is supported on a carriage 26 or 28 respectively. The luffing fly jib 12 in FIG. 3 is made up of two parts which can be kinked around bolt points 30. The carriage 26 is arranged in the region of these bolt points. The carriage 28 is arranged at the outer end of the luffing fly jib. At the inner end, the luffing fly jib is connected via bolt connections 32 to the adapter 24 of the main boom.

(7) Subsequently, in accordance with the representation according to FIG. 3b, the telescopic boom 10 is positioned steeply together with the adapter 24 and, as shown in FIG. 3c, is telescoped outwardly to the desired length. The telescopic boom 10 is raised by means of a luffing cylinder 45. During the steep positioning and outward telescoping, the luffing fly jib 12 is pulled up at the pivotally connected end, while the kink point and the free outer end of the luffing fly jib 12 roll off along the ground on the carriage 26 or 28 respectively. This can all be seen clearly from the representations 3b and 3c. The stay poles 18 of the luffing fly jib 12 are shown in FIG. 3c. Intermediate guying 31 is additionally shown here. Once the last telescopic section 11 has been extended and bolted, the spatial guying 22 is tensioned. The boom system hereby achieves its maximum stability, in particular also in the transverse direction of the longitudinal boom axis. At this time, the hoist rope 33 is not yet tensioned.

(8) It is now shown in FIGS. 3d and 3e how the luffing fly jib 12 is raised. During the raising, the luffing fly jib 12 is first lifted from the carriage 26 (cf. FIG. 3d) while the free outer end of the luffing fly jib 12 still rolls off on the carriage 28. Subsequently, the free end is also pulled up accordingly. The hoist rope 33 is also tensioned over the hook block 34 in FIG. 3e.

(9) The representation in accordance with FIG. 2 substantially corresponds to that in accordance with FIG. 3. Here, the luffing fly jib is, however, only made in one part and is therefore only supported on one carriage 28. However, it also again becomes clear from FIG. 2 that the spatial guying 22 is tensioned before the raising of the luffing fly jib 12.

(10) FIG. 4 shows a mobile crane 5 which has a similar structure to that in accordance with FIG. 3. In FIG. 4, the hoist rope is shown at 32 which is now no longer sheared into a hook block and held under tension by it in the new raising method of the boom. There is now a balance of forces in the raised telescopic boom 10.

(11) The weight of the part of the hoist rope above the main boom pulls the hoist rope in the direction of the hoist rope winch 34. The weight of the other part of the hoist rope 33 above the luffing fly jib 12 pulls the hoist rope away from the winch 34. There is a balance in this respect. However, on the outward telescoping of the telescopic boom 10, this balance is impaired. It could be disrupted in this respect. As soon as the part of the hoist rope above the tip boom 12 now becomes shorter than the part above the telescopic boom 10, the hoist rope 33 is retracted in an accelerated manner. Once the end of the hoist rope 33 has reached a pulley block 36 of the guying trestle 14, it falls in free fall in the direction of the crane. This risk is precluded in accordance with the solution shown in FIG. 4 in that an auxiliary rope 38 is connected to the hoist rope 33′. The hoist rope 33′ is thereby held tautly in the embodiment shown in FIG. 4. The hoist rope 33 in FIG. 4, which is drawn as slack here, therefore only serves for explanation. The auxiliary rope 38 is loaded with a defined tension via an auxiliary winch 40 which is arranged at the superstructure of the mobile crane 5. The tension is limited by a relief valve and the auxiliary rope 38 can be unwound from the auxiliary winch 40. The performance of the auxiliary winch drive is selected so that it can only wind up the auxiliary rope at an appropriate speed. After the raising of the luffing fly jib, the auxiliary rope is released again since the hook block 34 tensions the hoist rope 33′ in this state again.