Tower crane

Abstract

The invention relates to a tower crane having a tower which carries a jib, from which a hoisting cable runs off, wherein a guying system is provided and runs, at least in part, along the tower and is spread out, by means of guy supports, in a direction transverse to the longitudinal centre plane of the crane, this plane running through the tower and the jib, wherein at least one pair of guy supports which are spread out in a V-shaped manner are articulated on the tower, between the lower end of the latter and the jib.

Description

[0001] The present invention relates to a tower crane with a tower supporting a boom from which a hoist cable extends, wherein a bracing system is provided which runs at least partially along the tower and is spread out by means of bracing supports transversely to the crane longitudinal mean plane which passes through the tower and the boom.

[0002] In order to be able to support high loads with tower cranes that have relatively large jibs, i.e., long boom lengths, it is known to brace the boom, whereby usually one, two or three bracing cables or rods are led from a tower top extending above the boom or from a boom pivot point to the boom and articulated there.

[0003] If a counter jib is present to support the ballast weight, the guying is usually routed to the rear of this counter jib. On tower cranes without a counter jib, the guying is routed downwards via the rearward-leaning tower top or guy wire.

[0004] The guy wires, guy rods, or occasionally guy chains, typically run in the crane's longitudinal center plane, which passes through the tower and the boom, to counteract the vertical loads and the resulting bending and tilting moments acting in the crane's longitudinal center plane. These vertical loads largely originate from the suspended lifting load but also include the boom's own weight. This prevents or at least limits excessive boom deflection in the aforementioned longitudinal center plane (see DE 9316113 U1).

[0005] However, the stability and thus the load-bearing capacity of the crane is also limited by twisting of the crane structure transversely to the longitudinal median plane of the crane, whereby transverse loads transverse to the longitudinal median plane of the crane are mainly introduced into the crane structure by laterally acting wind, but also pendulum loads or rotational accelerations with attached loads when twisting the crane around the upright tower axis can induce transverse forces in the boom.

[0006] To prevent twisting of the boom perpendicular to the crane's longitudinal center plane, or to stiffen the boom against lateral forces, while simultaneously achieving bracing against the predominantly acting vertical loads, it has been proposed to brace the crane boom spatially and to run the guy wires over V-shaped, splayed guy wire supports mounted on the back of the boom. For example, German patent DE 31 05 771 A1 shows a tower crane with a telescopic tower supporting a boom on the top of which V-shaped, splayed guy wire supports are mounted. Two guy wires run over the projecting ends of the V-shaped guy wire supports and converge at a guy wire support projecting horizontally rearward from the boom's pivot point on the tower. From this support, a guy wire is then led down in the crane's longitudinal center plane to the slewing platform and attached there to the ballast beam.This spatial bracing of the boom via V-shaped, splayed guy wires prevents bulging or lateral twisting of the boom. At the same time, it makes it possible to straighten the boom by precisely adjusting the length of the two guy wires.

[0007] For derrick cranes with a luffing base boom, it has already been proposed to provide a two-strand bracing system, which in the area of ​​the base boom comprises two spaced-apart boom arms, see JP 2011 57341 A1 and JP S47 37785 Y1.

[0008] On the other hand, it has also been proposed to relocate the guy wires running down the tower from the crane's longitudinal center plane and to provide, so to speak, right and left guy wires. These would be attached at the top to the tower's pivot point or to an upper slewing platform provided there, and at the bottom to the lower slewing platform that rotates the tower. For example, German patent application DE 10 2013 011 489 A1 shows a guy wire system in which grid sections are bolted to the lower slewing platform, extending perpendicularly from the side of the slewing platform and transversely to the load direction. Tensioning devices are bolted to the outer ends of these grid sections, leading to guy wires on the upper fixed slewing platform.

[0009] Despite the guy wires running down the length of the tower, it remains susceptible to twisting laterally under transverse loads, such as those encountered in strong crosswinds, perpendicular to the crane's longitudinal center plane. In such cases, the tower is not only subjected to stress similar to a bending beam, but also to increased buckling stress due to the additional high vertical loads acting like a compression member. This susceptibility to buckling is known to be further exacerbated when an elongated, slender bar profile has already undergone some bending in addition to the compressive stress from transverse forces. Such losses of stability in bar-like structures due to lateral deflection under axial compressive stress are sometimes referred to as Euler buckling cases.

[0010] To increase the stability of the crane structure, the cross-sections of the boom and tower are typically enlarged and / or the wall thicknesses of the structural components are increased, or, in the case of truss structures, the cross braces are reinforced. However, this leads to a reduction in efficiency, i.e., the ratio of the load the crane can lift to its own weight. Furthermore, the increased crane weight also negatively impacts assembly handling and compliance with permissible road transport weights.

[0011] The present invention is based on the objective of creating an improved tower crane of the type mentioned above, which avoids disadvantages of the prior art and advantageously develops the latter further. In particular, increased stability of the crane structure and thus safety in crane operation under lateral forces such as crosswinds should be achieved without deterioration or preferably with a simultaneous improvement in efficiency, i.e., the ratio of lifting capacity to the crane's own weight.

[0012] According to the invention, the aforementioned problem is solved by a tower crane according to claim 1. Preferred embodiments of the invention are the subject of the dependent claims.

[0013] It is therefore proposed to brace the tower against lateral loads and buckling, including between its ends, using the bracing system. According to the invention, the bracing system comprises at least a pair of spatially splayed bracing struts, which are hinged to the tower between its lower end and the boom. The splayed bracing struts on the tower allow compressive and / or tensile forces with a component perpendicular to the crane's longitudinal center plane to be transferred between the tower and the bracing system, thus stabilizing the tower against bulging and buckling.In particular, the guying supports transfer tensile and / or compressive forces from the tower to the guying elements running along the tower, which may be designed, for example, in the form of guy ropes, guy rods or guy chains, transverse to the longitudinal axis of the tower, wherein the transferred tensile and / or compressive forces of advantageous components may be both transverse to the crane longitudinal mean plane and parallel to the crane longitudinal mean plane.

[0014] In an advantageous further development of the invention, two or more pairs of V-shaped splayed guy wires can be distributed along the tower and articulated to support different tower sections lying at different heights against transverse forces or buckling of the tower profile.

[0015] The V-shaped, splayed support structures can be designed in fundamentally different ways, in particular comprising elongated beams inclined at acute angles to each other, which have an approximately straight course, but can also be curved or kinked.

[0016] The guy wire supports can also be designed in the form of a frame-like guy wire frame. The V-shaped spread is defined by the attachment points of the guy wires or tensioning elements on the guy wire supports or frame on the one hand, and the attachment points of the guy wire supports or frame on the tower on the other, whereby, if necessary, only one common attachment point on the tower may be provided. In this respect, the guy wire supports can also form part of a guy wire frame or frame, or of a guy wire support structure running transversely to the guy wires.

[0017] In an advantageous further development of the invention, at least one pair of guy wires can be attached to a boom pivot point of the tower to which the boom is attached, and at least one further pair of guy wires can be attached to an intermediate tower section provided between the lower tower end section and the said boom pivot point, in order to brace the highly stressed boom pivot point against lateral twisting and transverse forces and to brace the tower at the intermediate section against buckling or lateral deformation.

[0018] Advantageously, the aforementioned two pairs of guying supports on the boom pivot and the tower intermediate section spatially brace the guying means in such a way that the boom pivot and the tower intermediate section are braced against both transverse forces and transverse deformations perpendicular to the crane longitudinal center plane and against longitudinal forces and deformations parallel to the crane longitudinal center plane.

[0019] In particular, a lower pair of V-shaped splayed guy wires can be hinged to the tower in a lower third of the tower, for example in the range of 10% - 50% of the tower height when measured from below the base of the tower.

[0020] Alternatively or additionally, a pair of V-shaped splayed guy wires can be hinged to an intermediate tower section at a height in the range of 30% - 60% or 40% - 70% of the tower height, where the tower height refers to the vertical extent of the tower from its lower end to the height of the pivot point of the boom on the tower and does not include any tower top that may be planned.

[0021] In an advantageous embodiment of the invention, the guy wires along the tower can be guided in a guying plane that extends vertically and perpendicularly to the crane's longitudinal center plane and is arranged at a distance from the tower on the rear side of the tower facing away from the boom. The guy wires are thus offset from the tower towards the rear and simultaneously spaced apart from each other transversely to the crane's longitudinal center plane, so that the guying along the tower can absorb both longitudinal forces in the crane's longitudinal center plane and transverse forces.

[0022] In particular, the guy wires can essentially run straight past the at least one pair of spatially splayed guy wires, which are hinged to the tower between its lower end and the boom pivot point on the tower, or they can be only slightly bent at the guy wires, for example at an angle of 160°–180° or 170°–180°. With such a geometry or guidance of the guy wires, shear forces or tensile and / or compressive forces between the tower and the guy wires are essentially only transmitted via the guy wires when shear forces, for example in the form of crosswinds, act on the tower or when the tower threatens to buckle or bulge.Normally, the guy wires, which are under high tension in the direction of pull, do not exert any prestress on the tower, provided there are no significant external wind loads or other lateral forces acting on the tower or boom. Instead, they essentially pull straight past the guy wire supports that are hinged to the tower. This applies at least to a lower pair of guy wire supports or a pair of guy wire supports hinged to the tower's intermediate section. A pair of guy wire supports attached to the upper end of the tower or to the boom's pivot point can provide for a greater deflection of the guy wires to redirect them towards the boom.

[0023] In an advantageous further development of the invention, the guy wires can be articulated with their lower ends to a rotating and / or support platform of the tower crane supporting the tower, wherein the pivot points on the rotating and / or support platform can be located essentially vertically below the pivot points of the guy wire supports for the guy wires.

[0024] At least one configuration of the guy wire support pair is possible: the attachment points of the guy wires on the turntable and / or support platform are essentially vertically below the attachment points on the guy wires. In another configuration, which can be achieved by adjusting the guy wires and / or the attachment points of the guy wires, the attachment points on the turntable or support platform can be offset from the vertical by the attachment points on the guy wires.

[0025] To enable stronger bracing of the crane structure against vertical loads or forces in the crane's longitudinal center plane, or stronger bracing against lateral forces such as wind loads, depending on the different operating conditions, or to allow for variable adjustment of the bracing ratio in the longitudinal and transverse directions, an advantageous embodiment of the invention can provide an adjustment device for variably setting and fixing a spread angle of the bracing supports. Increasing the spread angle increases the distance between the bracing elements, i.e., transversely to the crane's longitudinal center plane, and thus increases the bracing effect against lateral forces or transverse deformations transversely to the crane's longitudinal center plane. Conversely, decreasing the spread angle increases the bracing effect in the crane's longitudinal center plane and thus reduces the lateral force bracing.

[0026] The aforementioned spread angle, as mentioned above, refers to the spread of two imaginary straight lines, one passing through the pivot point of the guy wire on the guy wire support and the other through the pivot point of the guy wire support on the tower. This angle is therefore independent of the specific contour of the guy wire supports or the guy wire frame. Consequently, the adjustment device can also be designed differently.

[0027] If, for example, two separate guy wire supports, such as elongated beams, are hinged to the tower, a spreader drive or the aforementioned adjustment device can include a pivoting mechanism to pivot the two guy wire supports further apart or closer together. If, however, a frame-like guy wire support is provided, which can, for example, include a crossbeam between the pivot points of the guy wire, then an extendable crossbeam can be provided, and the spreader drive can include a telescoping drive to spread the guy wires further apart by extending the crossbeam and, conversely, to bring them closer together by shortening the crossbeam.

[0028] The aforementioned spreading drive can be externally powered, for example, by a hydraulic cylinder or a spindle drive. Alternatively or additionally, a manually operated spreading drive can also be provided, for example, to set a desired spreading angle before the crane is erected.

[0029] Alternatively or additionally to an adjustable spread angle, an adjustment device for setting and variably defining the effective length of the guy wires can also be provided, in order to change the path of the guy wire by adjusting the effective length of the guy wires. For example, telescopic guy wires can be provided, advantageously with a telescoping drive to extend and / or retract the guy wires using external power, which allows for convenient adjustment even with the crane already erected or mounted, for example, when a day of operation with strong crosswinds is expected. Alternatively, it may also be sufficient to provide a manually operated length adjustment device, such as a spindle drive or the ability to bolt two support beam sections together, to adjust the effective length of the guy wires, for example, during crane assembly.The effective length mentioned refers to the distance between the pivot point of the guy wire on the guy wire support and the pivot point on the tower.

[0030] According to the invention, the bracing is spatially spread out across the interface between the tower and the boom, and can be spatially spread out both along the tower and along the boom transversely to the crane's longitudinal center plane. Such spatial bracing across the tower-boom interface allows the entire crane structure, including the tower and boom, to be braced or secured against lateral forces, and also prevents or limits lateral movement of the boom. This allows for a significantly increased lifting capacity without noticeably increasing the crane's own weight.

[0031] The invention is explained in more detail below with reference to a preferred embodiment and the accompanying drawings. The drawings show: Fig. 1: a side view of a tower crane with bracing bracing the tower and the jib, Fig. 2: a rear view of the tower crane made of Fig. 1 , which shows the spreading of the bracing transverse to the crane longitudinal mean plane and the effective lever arm of the bracing means along the tower transverse to the crane longitudinal mean plane, and Fig. 3: a top view of the tower crane from above, showing the spatial course of the bracing means along the boom and the tower.

[0032] As the figures show, the tower crane 1 comprises a tower 2 which stands upright in operation and carries a boom 3 which is hinged to an upper end section of the tower 2 and cantilevers out from the tower 2.

[0033] A hoist rope 4 runs from the boom 3 to raise and lower a load-handling device, such as a load hook. This hoist rope 4 can run from a trolley 5, which can be moved along the boom 3 by a trolley drive. Alternatively, the hoist rope 4 could also run from a boom tip, particularly if the boom 3 is luffing, although a trolley 5 can still be provided even with a luffing boom 3. The boom 3 can be in a horizontal position in at least one operating position.

[0034] The tower 2 is mounted on a slewing and / or support platform 6, which can be rotated about an upright axis by a slewing mechanism, so that the entire crane can be rotated about the upright axis, which can be coaxial with the tower's longitudinal axis. Alternatively, instead of such a bottom-slewing crane, the tower crane 1 can also be designed as a top-slewing crane, in which case the jib 3 is rotatably mounted on the tower 2 about the upright axis. The bracing 7, which will be described later, can be articulated to the upper slewing platform for the jib in such a top-slewing crane.

[0035] As the figures show, the tower 2 and the boom 3 are braced by a guying system 7, which includes guying elements 8 running along the boom 3 and along the tower 2, which can be in the form of guying cables, guying rods or possibly also guying chains or mixed forms thereof.

[0036] As the figures show, the guy wires 8 can have one or more pivot points on the boom 3, for example, being pivoted in an outer half or an outer third of the boom 3 to extend back towards the tower 2 above the back of the boom 3.

[0037] The guy wires 8 can be guyed by one or more guy supports 9 on the boom 3, for example by means of a guy support between the outer attachment point of the guy wire 8 and the tower 2 and another guy support 9 in the area of ​​the pivot point with which the boom 3 is articulated to the tower 2.

[0038] Advantageously, the aforementioned guying supports 9 are designed in the form of spatial guying brackets or in the form of pairs of V-shaped guying supports, so that the guying elements 8 are guided across the jib 3 at intervals across the longitudinal median plane 10 of the tower crane 1, which runs through its tower 2 and its jib 3. The guying supports 9 can be spread apart to such an extent that the guying elements 8 above the jib 3 are at least partially spaced further apart than the width of the jib 3. In particular, in the area of ​​the inner half or an inner third of the jib 3, i.e., the half or third closer to the tower 2, the distance between the guying elements 8 can be greater than the transverse extent of the jib 3 across the aforementioned longitudinal median plane 10.

[0039] The aforementioned guy wire supports 9 on the boom 3 can be splayed upwards in a V-shape, for example at an angle of 2 x 10° to 2 x 60°, or 2 x 15° to 2 x 40°, or 2 x 10° to 2 x 20°. The guy wire supports 9 are inclined symmetrically to the longitudinal median plane 10.

[0040] The bracing 7 also includes bracing elements 11 running from top to bottom along tower 2, which are supported on tower 2 by means of bracing struts 12. How Figure 2 and Figure 3 As shown, the guy wires 11 are also spread out or spaced apart along the tower 2 transversely to the longitudinal median plane 10 of the tower crane 1 in order to be able to absorb both transverse forces transverse to the longitudinal median plane 10 and longitudinal forces in the longitudinal median plane 10.

[0041] The guy wires 11 are supported on the tower 2 by means of several pairs of guy wire supports 12 in order to be able to transmit tensile and / or compressive forces between the tower 2 and the guy wires 11.

[0042] The pairs of guy wires 12 are spread out in a V-shape and arranged symmetrically to the longitudinal median plane 10, with the guy wires 12 extending to the rear of the tower 2 facing away from the boom 3.

[0043] How Figure 2 and Figure 3 As shown, the spread angle β of the guy wires 12 can be such that the distance between the guy wires 11, or across the longitudinal median plane 10, is greater than the transverse extent of the tower 2 across said longitudinal median plane 10. The guy wires 12 can be spread out in a V-shape from the rear of the tower 2, for example at an angle β of 2 times 10° to 2 times 60°, or 2 times 15° to 2 times 40°, or 2 times 10° to 2 times 20°.

[0044] In Figure 2 The distance of the guy wires 11 from the longitudinal median plane 10 is denoted by the dimension X_2, which indicates the effective lever arm of the guy wire 11 with respect to the longitudinal median plane, or is a measure for the bracing of transverse loads. The distance X_2 of the guy wires transversely from the longitudinal median plane 10 can vary and, for example, be in the range of 60% to 500%, 75% to 300%, or 100% to 200% of the width 13 of the tower 2, i.e., its extent transverse to the longitudinal median plane 10.

[0045] Depending on the width of tower 2, the spacing of the guy wires 11 from the longitudinal center plane 10 can also be in other areas. Advantageously, the spacing can be chosen to be at least large enough that the guy wires 11 span a greater span than the width of tower 2. For example, in the area of ​​tower 2, the guy wires 11 can span a span of 2 times X_2, which is approximately twice the width of tower 2, if the crane 1 is positioned according to Figure 2 viewed from its back.

[0046] How Figure 1 As shown, the guying means 11 can run along the tower 2 in a guying plane 14 which extends upright and perpendicular to the longitudinal median plane 10, wherein said guying plane 14 can advantageously be oriented at least approximately vertically.

[0047] The bracing plane 14 is spaced away from the tower 2 on its rear side, i.e. opposite the boom 3, so that the bracing tensioning means 11 can also bear loads in the longitudinal median plane 10 and brace the tower against vertical loads.

[0048] How Figure 3 As shown, the spreading angle β realized by the guying supports 12, which are hinged to the tower 2, can be in the range of 2 times 5° to 2 times 60° or 2 times 10° to 2 times 50° or 2 times 15° to 2 times 40°, wherein the said spreading angle β is defined by the connecting lines that pass on the one hand through the pivot points of the guying tensioning device 11 on the guying supports 12 and on the other hand through the pivot points of the guying supports 12 on the tower 2.

[0049] Advantageously, the guy wires 12 can be variably adjustable with respect to the spreading angle β, wherein an adjusting device 15 can, for example, comprise a hydraulic cylinder or a spindle drive which is arranged between the paired guy wires 12 and engages the two guy wires 12 to spread them further apart or less. This spreading capability of the guy wires 12 is in Figure 2 shown, where the course of the guying means 11 is represented by the dashed lines when the guying supports 12 are spread further apart, while the solid lines show the course of the guying means when they are spread less far apart.

[0050] Alternatively or in addition to an adjustable spreading angle β, the guying supports 12 can also be designed to be length-variable, for example telescopic, and may have a telescoping drive in order to be able to variably adjust the course of the spatial guying 7 along the tower 2 by changing the length of the guying supports 12.

[0051] The adjustability of the spatial bracing 7 along the tower 2 allows the bracing conditions to be adapted to the operating conditions. For example, if the crane is used in strong crosswinds, the bracing elements 11 along the tower 2 and / or along the boom 3 can be spaced further apart by widening the bracing struts 12 and / or bracing struts 9, or by extending or lengthening the bracing struts. This provides greater leverage against lateral forces or loads on the crane structure and enables the crane to withstand heavier lateral loads. Conversely, if the crane is used in calm conditions and / or with very heavy loads requiring maximum bracing in the longitudinal center plane 10, it may be advantageous to move the bracing struts 12 closer together or to space the bracing elements 11 and / or bracing elements 8 less far apart laterally.

[0052] As the figures show, the guy wires 11 run approximately straight past the lower guy wire supports 12, which can be located in the lower third of the tower 2, or are only slightly bent depending on the splay angle of the guy wire supports 12. In particular, the pivot points of the guy wires 11 on the rotating and / or support platform 6 can be positioned essentially vertically below the pivot points of the guy wire supports 12 for the guy wires 11, so that the guy wires 11 run essentially straight or vertically downwards from the guy wire supports 12 to the rotating or support platform 6.

[0053] How Figure 1To clarify, the bracing 7 is spatially routed across the interface between tower 2 and boom 3, whereby bracing means 16 can connect the bracing means 11 running along tower 2 with the bracing means 8 running above boom 3 and / or run from the pivot points of the upper tower bracing supports 12 to the pivot points of inner boom bracing supports 9 or connect them together.

Claims

1. A tower crane having a tower (2) which carries a jib (3), from which a hoisting cable (4) runs off, wherein a guying system (7) is provided and runs, at least in part, along the tower (2) and is spread out, by means of guy supports (9, 12), in a direction transverse to the longitudinal centre plane of the crane (10), this plane running through the tower (2) and the jib (3), characterised in that at least one pair of guy supports (12) which are spread out in a V-shaped manner are articulated on the tower (2) between its lower end and the jib (3).

2. The tower crane according to the foregoing claim, wherein two or more pairs of guy supports (12) which are spread out in a V-shaped manner are articulated on the tower (2) in a distributed manner along the tower (2) and project rearwardly from the tower (2) toward the rear side facing away from the jib (3).

3. The tower crane according to any of the foregoing claims, wherein at least one pair of spread-out guy supports (12) is articulated on an upper jib articulation part (17) of the tower (2) on which the jib (3) is articulated, and at least another pair of guy supports (12) is articulated on an intermediate tower portion (18) provided between the lower tower end portion (19) and the jib articulation part (17).

4. The tower crane according to the foregoing claim, wherein said further pair of guy supports (12) is articulated on the tower (2) in a lower third of the tower (2).

5. The tower crane according to any of the foregoing claims, wherein bracing tension means (11) are guided along the tower (2) in a bracing plane (14) extending upright and perpendicular to the longitudinal centre plane (10) of the crane and arranged at a distance from the tower (2) on a tower rear side facing away from the jib (3).

6. The tower crane according to any of the foregoing claims, wherein the bracing tension means (11) run substantially straight past the at least one pair of guy supports which are spread out in a V-shaped manner and which are articulated on the tower (2) between its lower end and the jib (3), or have a bend angle in the range of 160° to 180° or 170° to 180° at said pair of guy supports (12).

7. The tower crane according to any of the foregoing claims, wherein the bracing tension means (11) are articulated with their lower ends on a revolving and / or supporting platform (6) supporting the tower (2), wherein the articulation points (20) on the revolving and / or supporting platform (6) are arranged substantially vertically below the articulation points (21) of the guy supports (12) for the bracing tension means (11).

8. The tower crane according to any of the foregoing claims, wherein an adjustment apparatus (15) is provided for variably adjusting and determining a spread angle β of the guy supports (12) articulated on the tower (2).

9. The tower crane according to the foregoing claim, wherein the adjustment apparatus (15) comprises a spreading drive, preferably in the form of a hydraulic cylinder or a spindle drive, for motorized spreading-out of the guy supports (12).

10. The tower crane according to any of the two foregoing claims, wherein the adjustment apparatus (15) has an adjustment area for the spread angle β in the range of 2 times 10° to 2 times 60° or 2 times 10° to 2 times 45° or 2 times 15° to 2 times 30°.

11. The tower crane according to any of the foregoing claims, wherein an adjustment apparatus is present for adjusting and variably determining a length of the guy supports (12), the guy supports (12) being preferably configured to be telescopic.

12. The tower crane according to any of the foregoing claims, wherein the guying system (7) is led beyond the interface between the tower (2) and the jib (3) in a spatially spread-out manner and is spatially spread out both along the tower (2) and along the jib (3) in a direction transverse to the longitudinal centre plane (10) of the crane.

13. The tower crane according to any of the foregoing claims, wherein the tower (2) is configured to be tiltable and / or telescopic and / or the jib (3) is configured to be foldable against the tower (2), and wherein the tower crane is configured as a mobile truck crane and has an undercarriage suitable for road transport, on which the tower (2) and the jib (3) are erectably mounted.

14. The tower crane according to any of the foregoing claims, wherein the bracing tension means (11) have, along the tower (2) in a direction transverse to the longitudinal centre plane of the crane (10), a distance from each other which is greater than the width of the tower (2) measured transversely to the longitudinal centre plane of the crane (10), wherein the distance of the bracing tension means (11) from each other along the tower (2) is in the range of 125% to 500% or 125% to 300% or 150% to 300% of said width of the tower (2) transverse to the longitudinal centre plane of the crane (10).

15. The tower crane according to any of the foregoing claims, wherein the bracin tension means (11) run substantially parallel to each other along the tower (2).

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