Crane

Abstract

Crane, in particular mobile crane, with a lattice boom (10), a derrick boom (40) and a boom bracing (20) extending from the derrick boom (40) to the boom tip (11), wherein at least one bracing block (30) is provided, which is attached to the lattice boom (10) between the derrick boom (40) and the boom tip (11) and is connected to the boom bracing (20), wherein the design of the boom bracing block (30) is suitable for transmitting compressive and / or shear forces in order to apply a compressive and / or shear force to the boom (10) via the bracing (20) during crane operation, characterized in that the at least one bracing block (30) comprises at least two interconnected side elements (30a, 30b), and wherein the at least one bracing block (30) is designed in a three-dimensional lattice structure.

Description

[0001] The invention relates to a crane, in particular a mobile crane, with a lattice boom, a derrick boom and a boom bracing system led from the derrick boom to the boom tip, wherein at least one bracing block is provided which is attached to the boom between the derrick boom and the boom tip and is connected to the boom bracing system.

[0002] It is well known to guy lattice booms during crane operation. The guying typically runs along the back of the boom, with the guying connected to the crane or boom at each end. To limit boom deflection during erection and crane operation, it is already known to use an additional guying device, for example, in the form of another guying support, between the connection points of the guying. The guying runs over this support. The resulting angle of the guying creates an upward tensile force in the additional guying device when it is under load. This tensile force pulls the boom upwards, thereby limiting the overall deflection of the boom system. The additional guying device was usually designed as a cable structure or a lightweight steel structure.

[0003] In Fig. Figure 1a shows a schematic diagram of such a boom system. Here, a lattice boom 1 is braced by means of a guy wire 2. An additional guy wire 3, mounted in the middle section of the boom 1, transfers a tensile stress applied by the guy wire 2 to the boom 1, thus limiting its deflection in the area of ​​the additional guy wire 3. Fig. Figure 1b illustrates the deflection of the boom without additional bracing, while Fig. Figure 1c illustrates the deflection of the boom 1 limited by the support 3. The hatched lines 1b and 1c show the possible deflection of the boom 1 during the erection and operation of the crane, respectively.

[0004] Cranes and crane booms are increasingly being designed with longer dimensions, leading to greater deformation of the boom system during crane operation. A growing problem is the lateral deformation of the boom system caused by transverse forces, such as wind, tilting, or imperfections. An example illustrates this. Fig. Figure 2 shows a rear view of the crane. The boom 1 is subjected to the acting shear force F. QLaterally deformed. The lateral deformation is further increased by attaching the load 100 to the load hook 101. Second-order theory plays a role here, meaning that the equilibrium of the deformed system is considered. Forces that had no effect on the undeformed system now acquire an effect. Due to an inclination α or a transverse load 102, such as wind, the boom 1 experiences a deflection from its ideal orientation in the luffing plane 103. The guy wire 20 introduces a holding force into the main boom 1; moreover, according to the illustration in Fig. 2 a further shear force F Q, Absp into the main boom 1, which further increases the lateral deformation of boom 1.

[0005] Furthermore, bending moments occur at the boom system during crane operation, especially when the boom 1 is set at a steep angle and a load is attached. This is shown, for example, in the Fig. 3a, Fig. 3b, which is a fixed-tip crane configuration ( Fig. 3a) and with a rocking tip ( Fig. 3b) show. A bracing 2 running from the derrick boom 4 to the boom tip simultaneously serves as the luffing drive for the boom 1. The behavior is comparable for both crane configurations. During crane operation with the boom 1 at a steep angle, high bending moments M occur to the rear or upwards. B in the area of ​​the boom tip or the upper part of boom 1, as indicated by the hatched area. Conventional auxiliary guy wires cannot counteract this bending moment, as they only introduce a tensile force into the boom system 1, meaning that the bending moment is theoretically increased further. For this reason, the auxiliary guy wires 3 are often only used during the erection phase.

[0006] A crane of this type is known from DE 36 40 068 A1 and JP S59-15 686 U. A similar crane is known from DE 31 05 771 A1.

[0007] The object of the present invention is to provide an improved bracing system for a boom, which in particular enables larger loads in crane operation.

[0008] This problem is solved by a crane according to the features of claim 1. Advantageous embodiments of the crane are the subject of the dependent claims following the main claim.

[0009] According to the invention, a crane is equipped with a lattice boom, a derrick boom, and a boom bracing system extending from the derrick boom to the boom tip. Preferably, the derrick boom is a fixed derrick boom. Furthermore, the boom bracing system is connected to at least one bracing block and runs from the derrick boom, via the bracing block, to the boom tip. During crane operation, the derrick boom is in a predefined position. When the main boom luffs, the cable of the derrick boom's adjustment block is tightened or loosened. This changes the geometric relationships between the derrick boom, the boom bracing system, the bracing block, and the main boom.

[0010] The tensioning bracket used is designed according to the invention such that, during crane operation, a compressive and / or shear force can be transferred from the tensioning system to the boom. Previous auxiliary tensioning devices served only to transfer a tensile force in order to specifically prevent downward deflection of the boom in the center. The use of a suitable design of the boom tensioning bracket with a lattice boom braced by a derrick boom now results in the transfer of a compressive and / or shear force from the tensioning system via the tensioning bracket to the lattice boom, preferably when the boom is in a steep angle. The compressive force counteracts the bending moments occurring during crane operation, thereby reducing deflection of the boom towards its back. The applied shear force prevents lateral deformation of the boom. In particular, this is intended to keep the tensioning system above the boom in place.The presence of at least one guy wire ensures that the guying runs along the back of the boom and is different from the previous design. Fig. 2. Deviates only slightly laterally from the boom's back. This reduces the lateral forces introduced onto the boom system by the bracing and minimizes the deformation of the boom system due to lateral forces.

[0011] A particularly preferred design of the guy wire frame includes at least two interconnected side elements or side panels. Furthermore, a three-dimensional lattice structure of the guy wire frame, ideally with a rectangular cross-section, is advantageous. A stable construction of the guy wire frame provides the necessary compressive and / or transverse stiffness for transferring the compressive and / or transverse forces from the guy wire to the boom system. The guy wire frame can also be made of, or at least incorporate, a fiber-reinforced composite material.

[0012] It can be provided that at least one guy wire is pivotally mounted on the lattice boom about a pivot axis perpendicular to the boom's longitudinal axis. Guy wire designs that allow the guy wire to be folded or spread are also advantageous. The foldability allows it to be folded against the boom system for crane transport. For example, the guy wire can be designed to achieve a spreading of the guy wire, i.e., at least two guy wire strands run over the guy wire. In an advantageous embodiment, the angle of the guy wire for spreading the guy wire can be variable.

[0013] It is also possible to mount the guy wire bracket firmly to the lattice boom.

[0014] The same applies to the guying, which can be either movable or fixed to the guying block. It is also possible to run guying, in particular guying cables, over the guying block.

[0015] Preferably, the at least one guying bracket is arranged in the middle section of the boom, i.e., centrally between the derrick boom and the boom tip. When using multiple guying brackets, these can be distributed along the boom's longitudinal axis and mounted on the boom system.

[0016] In the crane according to the invention, the guying preferably serves as a luffing drive for the boom; that is, by actuating the guying, for example by means of a guying winch, the boom system can be raised or lowered accordingly. The guying can also be actuated by means of an adjusting block that connects the guying to the derrick boom.

[0017] A rectangular, V-shaped, or trapezoidal design for the guy wire is also conceivable. The specific shape of the guy wire depends on the application and serves primarily to spread the guy wires.

[0018] According to the invention, the tensioning bracket is suitable for applying compressive and / or lateral forces to the boom system. However, it is also conceivable that the design of the tensioning bracket is suitable for absorbing the tensile forces acting on the boom system.

[0019] Preferably, the length of at least one guy wire is adjustable, allowing the lateral distance of the guy wire to the boom to be adjusted. Ideally, the length of the guy wire can be changed during crane operation.

[0020] Further advantages and features of the invention will be explained in more detail below with reference to an exemplary embodiment illustrated in the drawings. The drawings show: Fig. 1a, Fig. 1b, Fig. 1c: a cantilever system according to the state of the art and schematic diagrams to explain the previous mode of operation, Fig. 2: a schematic diagram to illustrate lateral forces on the boom, Fig. 3a, Fig. 3b: Schematic diagrams illustrating bending moments acting on a conventional cantilever system, Fig. 4: a representation of the boom system of the crane according to the invention; Fig. 5: a schematic diagram of the crane to illustrate its operation; Fig. 6: an alternative embodiment of the guying bracket for the crane according to the invention and Fig. 7a, b: Schematic diagrams to further illustrate the operating principle of the crane according to the invention.

[0021] To reduce lateral deformation of the boom system, which reduces its load-bearing capacity, as well as the influence of load-induced bending moments, an additional bracing system was developed that, unlike previous additional bracing systems, can also absorb compressive and shear forces. The previous additional bracing systems were unable to do this.

[0022] An embodiment of the invention shows Fig. 4. The newly developed guying brackets 30 consist of two side sections 30a, 30b, which are connected to each other. To ensure that the guying brackets are suitable for absorbing compressive and lateral forces, they are constructed in a three-dimensional lattice structure. The arrangement of one or both lattice brackets 30 is located in the middle third of the boom 10, i.e., the remaining length of the main boom 10 from the uppermost guying bracket 30 to the boom tip 11 is approximately one-third of the total main boom length. A preferably double-strand guying system 20 is routed from the derrick boom 40 via the guying brackets 30 to the boom tip 11 and attached there. The guying system 20 can be composed of individual guy rods. However, the use of cable rigging is also possible. In the crane under consideration, the boom bracing 20 simultaneously represents the luffing drive, which is realized by an adjustment block 41 on the derrick boom 4 via the bracing rods 20.

[0023] The derrick boom 40 is in a predefined position during crane operation. When the main boom 10 luffs, the cable of the adjustment block 41 of the derrick boom 40 is tightened or loosened. This changes the geometric relationships between the derrick boom 40, the boom bracing 20, the bracing block 30, and the main boom 10.

[0024] The connection between the guying brackets 30 and the boom 10 is designed to pivot about a pivot axis perpendicular to the boom's longitudinal axis. Alternatively, the guying brackets 30 can also be rigidly connected to the boom system 10.

[0025] Essential for the design of the bracing 20 is that the bracing bracket(s) 30 hold the bracing 20 as far above the boom 10 as possible. This is, for example, Fig. Figure 5 shows a rear view of the crane system according to the invention. The bracing block 30 ensures that the bracing 20 runs along the rear of the boom 10 and, unlike in the Fig. 2 deviates only slightly laterally from the boom back. This allows the lateral forces F introduced onto the boom system by the bracing to be absorbed. Q The deformation of the boom system due to shear forces is reduced. The guying block 30 with its rigid side plates 30a, 30b is only very slightly deformed due to the shear forces.

[0026] To further enhance the effect of the guy wire 30, it can also be designed in a V- or trapezoidal shape, as is the case, for example, with the Fig. 6 can be seen. Due to the trapezoidal construction of the guy wire 30' of the Fig. 6 The spread of the boom bracing 20 is increased, which further enhances its effect.

[0027] Another advantageous application of the tensioning bracket 30 according to the invention is that, due to its compression-resistant construction, it also absorbs the bending moment M acting on the boom system 10 during crane operation. B reduced. This applies even more so to steep boom positions.

[0028] As this is the Fig. As can be seen in Figure 7, the guy wire 20 runs from the derrick boom 40 to the tip 11 of the main boom 10. The illustrated boom 10 is additionally equipped with a fixed lattice tip 13. Here, too, the guy wire 30 according to the invention is arranged after approximately two-thirds of the main boom length. As indicated by the direction of the arrow, a compressive force F is exerted by the guy wire 20. D inserted into the boom 10, which withstands the bending moment M B in the area of ​​the guy wire 30 counteracts this and significantly reduces boom deformation. A comparison of the Fig. 3a, Fig.Figure 7a shows the positive effect.

[0029] The same result is obtained for a crane to whose main boom 10 a luffing jib 12 or a hinged auxiliary boom is attached. Here too, bending moments M occurring in the area of ​​the guy wire 30 can B by applying a compressive force F D This can be significantly compensated for via the guy wire 30.

[0030] The essential features of the inventive bracing 20 and the bracing frame 30 are described below. The bracing frame 30 can withstand compressive forces, tensile forces, and lateral forces. This is achieved, for example, by a rectangular, trapezoidal, or V-shaped design of the bracing frame 30, which is constructed as a three-dimensional bracing frame from a lattice structure. The boom system can be configured with a single frame 30 or with several frames 30 arranged one behind the other. Furthermore, the bracing frames can be designed to be hinged in order to change their angle relative to the main boom 10. The three-dimensional design of the bracing frame 30 can also allow for adjustment of the spread to adjust the resulting spread of the bracing 20.

Claims

[1] Crane, in particular mobile crane, with a lattice boom (10), a derrick boom (40) and a boom bracing (20) extending from the derrick boom (40) to the boom tip (11), wherein at least one bracing block (30) is provided which is attached to the lattice boom (10) between the derrick boom (40) and the boom tip (11) and is connected to the boom bracing (20), wherein the design of the boom bracing block (30) is suitable for transmitting compressive and / or shear forces in order to apply a compressive and / or shear force to the boom (10) via the bracing (20) during crane operation. characterized by , that the at least one guy wire (30) comprises at least two interconnected side elements (30a, 30b), and wherein the at least one guy wire (30) is constructed in a spatial lattice structure. [2] Crane according to claim 1, characterized by, that at least one guy wire frame (30) is constructed in a spatial lattice structure from fiber composite materials. [3] Crane according to claim 1 or 2, characterized by , that the guying block (30) is rectangular or V-shaped or trapezoidal, in particular for spreading the guying (20). [4] Crane according to one of the preceding claims, characterized by , that at least one tensioning bracket (30) is pivotably mounted on the lattice boom (10) about a pivot axis perpendicular to the longitudinal axis of the boom or is firmly connected to the lattice boom (10). [5] Crane according to any one of the preceding claims, characterized by that the guy wire (20) is movably mounted or guided on the guy wire frame (30) or is rigidly connected to it. [6] Crane according to any one of the preceding claims, characterized by , that at least one guying block (30) is attached in the middle boom area. [7] Crane according to any one of the preceding claims, characterized by , that exactly one single guying block (30) is arranged on the lattice boom (10) or several blocks are mounted one behind the other on the boom system, so that the remaining main boom length from the uppermost guying block to the outermost boom tip (11) is about one third of the total main boom length. [8] Crane according to any one of the preceding claims, characterized by , that the guy wire (20) represents the luffing drive of the crane. [9] Crane according to any one of the preceding claims, characterized by that the guying block (30) is suitable to absorb the tensile forces acting on the boom system. [10] Crane according to one of the preceding claims, characterized in that the length of the at least one bracing block (30) is adjustable, ideally during crane operation.

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