Telescopic boom and mobile crane

Abstract

The present invention relates to a telescopic boom having a coupling section at whose lower shell at least one luffing cylinder mount, in particular a bolt mount, is centrally provided for fastening at least one luffing cylinder, wherein at least two closed sheet metal box structures for the load transmission from the luffing cylinder mount into the structure of the telescopic boom are provided at the support metal sheets of the luffing cylinder mount.

Claims

1. A telescopic boom having a coupling section having a lower shell and at least one luffing cylinder mount centrally provided for fastening at least one luffing cylinder to the telescopic boom, wherein two closed sheet metal box structures for load transmission from the luffing cylinder mount into the telescopic boom, adjoin respective support metal sheets of the luffing cylinder mount.

2. A telescopic boom in accordance with claim 1, wherein the sheet metal box structures are symmetrical with one another.

3. A telescopic boom in accordance with claim 1, wherein the sheet metal box structures extend from the support metal sheets in a direction of a boom tip obliquely to a longitudinal boom axis.

4. A telescopic boom in accordance with claim 1, wherein each of the sheet metal box structures has two side walls, a top metal sheet, and a terminal metal sheet.

5. A telescopic boom in accordance with claim 4, wherein an outer side wall of each of the sheet metal box structures and/or the top metal sheets of each of the sheet metal box structures is in two parts or in multiple parts.

6. A telescopic boom in accordance with claim 5, wherein an inner side wall is in one part.

7. A telescopic boom in accordance with claim 1, wherein the sheet metal box structures each have at least one inner standing metal sheet that is peripherally connected to the respective box structure and to the lower shell of the coupling section.

8. A telescopic boom in accordance with claim 7, wherein the standing metal sheet is arranged in a transition region between at least two wall elements of a two-part or multiple part outer side wall and/or of a top metal sheet.

9. A telescopic boom in accordance with claim 1, wherein the coupling section has a substantially perpendicular web region adjoining the lower shell.

10. A telescopic boom in accordance with claim 1, wherein one or more U buckling braces extending in a boom direction are arranged at the lower shell, with corresponding recesses for the buckling braces being provided in the sheet metal box structures.

11. A telescopic boom in accordance with claim 10, wherein the buckling braces are provided in a top metal sheet.

12. A telescopic boom in accordance with claim 1, wherein one or more wing metal sheets are provided that are oriented transversely to a longitudinal boom axis and that at least partly surround the lower shell starting from the mount.

13. A crane, in particular a mobile crane, having at least one telescopic boom in accordance with claim 1.

14. A telescopic boom in accordance with claim 1, wherein the at least one luffing cylinder mount is a bolt mount.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Further advantages and particulars of the invention will be explained in detail with reference to an embodiment shown in the drawing.

(2) There are shown:

(3) FIG. 1: a luffing cylinder mount for a telescopic boom known from the prior art;

(4) FIG. 2: the solution in accordance with FIG. 1 with a force flow drawn in;

(5) FIG. 3: the innovative structure for the luffing cylinder mount with a telescopic boom; and

(6) FIG. 4: a further illustration of the structure in accordance with the invention of FIG. 3 from a slightly different angle of view and with a force flow drawn in.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) FIGS. 3 and 4 now show the innovative structure of the telescopic boom system. A part region of the lower shell 20 of the telescopic boom can be seen that has the bolt mount for the connection of the luffing cylinder. The two bolt metal support sheets 21 are provided with respective reinforcement metal sheets for the mounting of bolt of the luffing cylinder. Two narrow, closed sheet metal boxes 25 adjoin them and are designed identically with one another. Both boxes 25 each comprise a two-part top metal sheet having the individual elements 26a, 26b that are connected to one another in the edge 26c. The two outer side walls of the sheet metal box structures 25 are also designed in two parts having the individual elements 27a, 27b that meet one another in the edge 27c. A terminal metal sheet 28 is provided at the front-side end. The inner side walls 31 of the sheet metal box structures are designed in one piece.

(8) A respective inner standing metal sheet 32 (only drawn once) is located in the interior of the two box sections 25 and is peripherally connected to the box 25 (side walls 27a, 27b, 31 and top metal sheet 26a, 26b) and to the lower shell 20. It can additionally be seen that the standing metal sheet 32 is connected to the box structure 25 exactly in the region of the edges 27c, 26c.

(9) A plurality of stiffening U buckling braces 29 are provided on the ovaloid section of the boom, i.e., on the semicircular lower shell 20. A perpendicular web region 33 adjoins the lower shell and connects the lower shell 20 to the upper shell, not shown, of the telescopic boom.

(10) Metal wing sheets 30 surround the semicircular lower shell 20 over a part region of its radius. FIGS. 3 and 4 only show one metal wing sheet 30; however, a metal wing sheet corresponding to the shown metal wing sheet 30 can likewise be arranged at the oppositely disposed side of the bolt metal support sheets 21 so that said metal wing sheet also at least surrounds a part portion of the radius of the lower shell 20. The selected length of the metal wing sheets 30 decisively depends on the present sheet metal thickness of the ovaloid section of the boom coupling part, in particular on the sheet metal thickness of the lower shell 20.

(11) The optimized force flow that is possible by the new structure of the luffing cylinder mount in accordance with the invention will now be described with reference to FIG. 4. The force flow is indicated by the arrows in FIG. 4. The introduction of the central luffing cylinder force WZ takes place as in the prior art via a bolt 12 drawn as a dashed line into the two bolt metal support sheets 21 having partial metal reinforcement sheets. The introduced force is then divided over the paths A, B, and C.

(12) A proportion of the force WZ flows over the path A respectively to the left and the right through the two-part outer side walls 27a, 27b and is transferred over the shear seams a into the lower shell 20 in the direction of the stiffer sectional region, i.e. it is transmitted into the perpendicular web region 33 adjoining the lower shell 20.

(13) A further proportion of the force flows in the path B through the single-part inner side wall 31 and over the shear seams c in the direction of the softer sectional region, i.e. into the lower shell. This is less critical than in the previous configuration of FIG. 2 since the load introduction into the boom takes place by shear over the shear seams c.

(14) The remainder of the force flows over the path C through the two-part top metal sheet 26a, 26b over pressure seams b in the direction of the stiffer sectional region (perpendicular web region 33). The disadvantages of the previous construction are thereby avoided that the force flows through two small buckling fields d reinforced by a kink 26c having a kink support metal sheet 32. The sheet metal thicknesses can here be selected as smaller than the required sheet metal thickness of the top metal sheet 4 in accordance with FIGS. 1, 2 of the prior art. The number of U buckling braces 29 can also be reduced since FIG. 1, for example, requires a further buckling brace that extends between the two buckling braces 8 with an insufficient sheet metal thickness of the lower shell 7. The terminal metal sheet 28 alleviates the unfavorable effect of the pressing at points in the current solution into the lower shell 20. If the advantage of the smaller lower shell sheet metal thicknesses is implemented, this can result in increased, lateral inflation of the ovaloid section. This can be restricted by a greater surrounding by the wing metal sheets 30.

(15) To summarize, it can be stated that the innovative structure permits an optimized force flow in which the force is conducted from the luffing cylinder directly in the direction of the stiffer sectional regions 33 of the boom coupling section. There is consequently a weight saving due to a plurality of effects. The lower shell 20 can possibly have a thinner design and additional U buckling braces 29 can optionally be dispensed with. The wide, thicker single-part top metal sheet in accordance with the prior art can be replaced with a total of four narrow, thinner top metal sheets 26a, 26b.

(16) The new structure can be manufactured less expensively, in particular when U bucking braces 29 (high manufacturing costs, high costs due to welding to the lower shell 20 and a subsequent straightening work due to weld seam distortion) are dispensed with. In addition the load capacity of the crane can be increased. Due to the omission of the U buckling braces, in particular at the lowest point of the half-shell 20, the free space toward the undercarriage is increased that may be required for the motor installation.