DK2984025T3 - Crane comprising longitudinal booms with weld-seamless transitions between beam cross sections - Google Patents

Description

The present invention relates to a crane, in particular to a revolving tower crane, having at least one lattice carrier that comprises a plurality of longitudinal beams that are connected to one another by transverse and/or diagonal struts, wherein at least one of the longitudinal beams has a beam cross-section varying over the beam length and/or has different beam cross-sections in different lattice fields. EP 0 928 769 A1, for example, shows a crane according to the category that has a boom that is configured as a lattice carrier and whose upper longitudinal beam becomes continuously thinner toward one end.

In cranes such as building cranes or harbor cranes, structural parts of the crane structure are frequently formed as lattice carriers in which longitudinal beams are connected to one another by transverse or diagonal struts. In revolving tower cranes, tower elements and boom parts and counter boom parts can be configured in the form of such lattice carriers. In other crane forms such as mobile telescopic cranes having a luffable boom, boom extensions such as luffing tips can be configured in the form of such lattice carriers. Structural parts are also configured in the form of trussed carriers or lattice carriers in other cranes such as derrick cranes and the like.

It is desirable in order to achieve a weight that is as low as possible with the best possible strength to adapt the cross-sectional portions of the longitudinal beams and transverse or diagonal struts to the forces present in the respective lattice field to utilize the material cross-sections and the strengths accompanied thereby in the best possible manner. This means with respect to the longitudinal beams that they should have different cross-sections per se in different longitudinal sections or in different lattice fields since different tensile forces act on the longitudinal beams in different lattice fields. To satisfy this demand, it has already been proposed to assemble a longitudinal beam from different beam parts and to weld the beam sections to one another. Such weld connections are, however, not all that simple in production, in particular when high-strength steels are used. On the other hand, the production effort is also increased by a more complex storage since different strut parts have to be kept in stock.

To avoid this more complex production effort, the longitudinal beams of the lattice carriers of cranes are therefore frequently produced with an unchanging cross-section in practice to be able to use a continuous beam. To satisfy the strength demands, the beam cross-section, however, has to be selected in this process such that it withstands the forces that occur in a lattice field that is subjected to the strongest stress, which then results in an overdimensioning in lattice fields have smaller dimensions and in a corresponding increase in weight.

It has also already been proposed to this extent to no longer manufacture the beams and struts of such a crane lattice carrier from steel sections, but rather to use different materials, in particular fiber-reinforced materials, such as section parts reinforced with carbon fiber and/or aramid fiber. In addition to very high production costs, such fiber material parts at times have disadvantages in shock resistance and resistance to impact without special protective measures, which is in particular problematic with fast-erecting cranes that are erected and dismantled frequently and that are often subject to rather rough conditions during transport and during assembly.

It is therefore the underlying object of the present invention to provide an improved crane of the said kind which avoids disadvantages of the prior art and further develops the latter in an advantageous manner. A high-strength, weight-optimized lattice carrier should in particular be provided that can be manufactured with a simple production effort and that can be used at different crane types, including fast-erecting cranes that are erected and dismantled frequently.

The named object is achieved in accordance with the invention by a crane in accordance with claim 1. Preferred embodiments of the invention are the subject of the dependent claims.

It is proposed to achieve the named object to adapt the longitudinal beam cross-sections to the force relationships present in the different lattice sections without welding the longitudinal beam sections of different cross-sections together from a plurality of beam parts, but rather to form the longitudinal beam from one piece or in one piece with material homogeneity at least sectionally despite a varying cross-section. In accordance with the invention, the at least one longitudinal beam that has a beam cross-section varying over the length or that has different beam cross-sections in different lattice fields has weld-free transitions between beam sections of different cross-sections. At least two beam sections of different cross-sections are produced with material homogeneity and free of a connection seam from one piece, with the named longitudinal beam in particular being able to be produced from steel or from a steel section.

The lattice carrier having such a longitudinal beam with weld-free transitions between beam sections of different cross-section can generally be used for different crane parts or structural parts of cranes, in particular in the range of tower parts and boom parts. A lattice carrier configured in the named manner can in particular be used as a boom or as a boom part of a crane, with the longitudinal beam with the different boom cross-sections and weld-free transitions therebetween being able to form the upper part of the boom part. The lattice carrier can generally, however, also be used in other crane carrier parts, with the longitudinal beam formed in the named manner in particular being of importance here when this beam forms the main beam substantially only exposed to tension in operation or such a main tension beam.

The lattice carrier formed in the named manner can in particular form a boom or boom part which is triangular in cross-section viewed overall and in which at least the upper beam has cross-section having weld-free transitions and varying over the length and is supplemented by two lower beams that are connected to one another and to the named upper beam by transverse and/or diagonal struts.

In accordance with the invention, the named at least one longitudinal beam has different beam cross-sections adapted to the respective tensile forces in the respective lattice field in the lattice fields between connected transverse and/or diagonal struts, in particular such that in lattice fields with higher tensile forces on the longitudinal beam, the latter has a thicker or larger beam cross-section and has smaller beam cross-sections in lattice fields with smaller tensile forces.

In this respect, the longitudinal beam has a substantially constant beam cross-section within a respective lattice field, i.e. between two adjacent connection points of transverse or diagonal struts. The beam cross-sections change from lattice field to lattice field and are adapted in the best possible manner to the load present in each lattice field. The cross-section changes can be provided in the region of the articulation points or connection regions of the transverse or diagonal struts.

In a further development of the invention, the longitudinal beam can comprise a sectional widening portion at at least one connector point of a transverse and/or diagonal strut and the beam cross-section tapers - viewed in the longitudinal beam direction - at both sides starting from said section widening portion. Weld connections of the named transverse and/or diagonal struts can be provided in a tension-reduced region in the region of the connection points of transverse and/or diagonal struts due to such sectional widening portions, i.e. the cross-section core of the longitudinal beam also remains weld-free in the region of the connection of transverse and/or diagonal struts.

The beam cross-section of the named longitudinal beam can in this respect reduce from lattice field to lattice field in at least one part of the lattice carrier. The beam cross-section can in particular reduce in a direction of the longitudinal beam from lattice field to lattice field toward the projecting end of the boom part when the boom part is a boom tip or a boom tip part. Depending on how the forces in the lattice fields, in particular the tensile forces on the upper beam result, other cross-sectional gradations or progressions can also be sensible.

In an advantageous further development of the invention, the named longitudinal beam with the changing beam cross-sections with weld-free transitions between the section portions or cross-sectional changes can be formed from a strip steel cable or from a solid material sectional part with an approximately rectangular cross-section. The use of a flat steel semifinished part allows a longitudinal beam to be used which is continuous over at least a part of the boom part and whose cross-section can be varied in a simple manner and can thus be adapted for different lattice fields to the forces present there.

The named longitudinal beam can in particular have a beam width changing over the length in at least one beam section with a substantially unchanging belt height. If a flat steel part of a strip steel part is used in the aforesaid manner, the thickness or height of the strip steel part remains substantially the same over the length while tapered or widened cross-sectional portions are achieved by varying the strip steel width.

In an advantageous further development of the invention, the named longitudinal beam can not only be adapted to different lattice carrier sections with respect to its beam cross-section, but can also have a curved and/or edged extent, for example to design the height of the lattice carrier differently in different lattice carrier sections - when the longitudinal beam is used as the upper beam - in particular to taper it toward a boom tip, and/or to provide a lattice carrier section having an increasing or decreasing height in addition to a lattice carrier section remaining constant in height and/or to provide lattice carrier sections having a height change of different amounts. In an advantageous further development of the invention, the longitudinal beam is in this respect also formed weld-free in the transition regions between mutually edged or curved longitudinal beam sections so that an integrally one-piece edged or bent region results having material homogeneity results.

The invention will be explained in more detail in the following with reference to a preferred embodiment and to associated drawings. There are shown in the drawings:

Fig. 1: a schematic side view of a crane in the form of a mobile fast erecting crane that is configured as a revolving tower crane whose tower bears a boom that is configured as a lattice carrier.

Fig. 2: a schematic side view of a boom part that is configured as a lattice carrier and that shows that the boom tip has a lattice carrier height decreasing toward the tip;

Fig. 3: a plan view of the boom part of Fig. 2 that shows the upper beam and its cross-sectional extent;

Fig. 4: an increased, detail plan view of the upper beam of the boom part of the preceding Figures; and

Fig. 5: an increased detail side view of the upper beam of the boom part of the preceding Figures.

As Fig. 1 shows, the crane 1 can be configured as a mobile fast erecting crane in the form of a revolving tower cane whose tower 2 bears a boom 3 and whose lower end is supported on a revolving deck 4 that is rotatable about an upright axis of rotation. The named revolving deck 4 is in turn seated on an undercarriage 5 that can be configured as a truck or in another manner, but that can optionally also be formed by a fixed, non-movable support base.

The boom 3 can be supported at the tower 2 luffable about a horizontal transverse axis, with the luffing up and down being able to take place via the guying 6.

The tower 2 and the boom 3 in this respect comprise lattice carriers of which at least one can be configured in the manner explained in more detail in the following. A boom part, for example the boom tip shown in Fig. 2, can in particular be configured as a lattice carrier 7 that comprises a plurality of longitudinal booms that are connected to one another by a plurality of transverse or diagonal struts 10. The named longitudinal beams can in particular comprise an upper beam 8 as well as two lower beams 9 so that the lattice carrier 7 has a triangular cross-section viewed overall. In general, however, other constellations are also conceivable, for example two upper beams with two lower beams or two upper beams with one lower beam depending on what strains the lattice carrier is subject to.

At least one of the named longitudinal beams can have the design described in more detail in the following with changing cross-sections and weld-free transitions, with this in particular being able to be the upper beam 8 subjected to the high tensile forces. The other longitudinal beams, in particular the lower beams 9, can have an unchanging beam cross-section viewed over the length, but can optionally also be configured with varying cross-sections analog to the upper beam 8.

As Fig. 3 and Fig. 4 show, the upper beam 8 can have different beam cross-sections in different lattice fields 11,12 and 13 - that are each disposed between two articulation points 14,15,16 or 17 of transverse or diagonal struts 10. As a comparison of Figures 2 and 5 with Figures 3 and 4 shows, the upper beam 8 can in this respect have a substantially unchanging section thickness while the section thickness varies over the length of the beam or differs from lattice field to lattice field. The section thickness and the section width are in this respect measured in two mutually perpendicular main axes of the cross-sectional profile, with the section thickness being able to be measured in the vertical direction and the section width being able to be measured in the horizontal direction when the lattice carrier is a boom part.

As in particular Fig. 4 shows, the section width can become smaller from lattice field to lattice field toward the boom tip, in particular from B1 over B2 and B3 up to B4, cf. Fig. 4.

The beam can have section widening portions 18 that can in particular be configured in the form of cross-section widening portions, cf. Fig. 4, in the region of the articulation points 14,15,16 and 17 of the transverse or diagonal struts 10, with the section thickness also being able to remain constant in the region of the section widening portions 18.

The cross-section transitions advantageously have, in particular also in the region of the section widening profiles 18, low notch-effective, in particular rounded, contours in order not to allow any tension peaks to arise. The transverse or diagonal struts 10 can be welded on in low tensile strain marginal sections of the upper beam 8 due to the named section widening portions 18.

As Fig. 3 and Fig. 4 show, the upper beam 8 can be configured in one piece without weld connections in the transition regions or in the sections of a lattice field itself despite the varying beam cross-sections of the upper beam over the total length of the boom part or of the lattice carrier 7. The named longitudinal beam 8 can in particular be produced from a flat steel section having a solid material cross-section.

As Fig. 5 shows, the upper beam 8 can comprise one or more edged portions 19, whereby the height of the boom part can be adapted in a varying manner in the desired fashion and can in particular be tapered toward the boom tip. The named edged portions 19 are in this respect advantageously made perpendicular to the shorter main axis of the beam cross-section, i.e. on an extent of the larger width in the horizontal direction, the section is edged or curved in the vertical direction.

The upper beam 8 can advantageously also be weld-free in the transition regions of the named edged portions 19 so that the beam can also extend with material homogeneity and integrally in one piece beyond the edged portions 19.

In a further development of the invention, the upper beam 8 can have a longitudinal chord or a central material core that can extend over the total length of the upper beam in a weld-free manner or can be configured with material homogeneity and integrally in one piece.

The upper beam 8 can in this respect - like the lower beams 9 and, optionally, also the transverse or diagonal struts 10 - be produced from high-strength steel, which is in particular sensibly possible because few weld joints are necessary or because changes of direction can be formed by edged portions and/or cross-section changes can be formed via the layout shape.

In addition, planned desired kink points can be installed in the lattice carrier 7 or boom in a simple manner.

Savings can furthermore be achieved in storage sine only a sheet metal section or a strip steel section has to be kept in stock for the upper beam.

The longitudinal beam design or shape described within the framework of the present application in this respect in particular makes the following advantages possible: - simple adaptation of the section width or of the section cross-section to the statically required beam cross-section and thus lightweight construction; - no weld connections are necessary between the upper beam fields even though the cross-section changes; - low-notch section widening portions can be provided at the points to which other carrier parts such as transverse and diagonal struts or connection lugs have to be welded; - a simple lattice height change can be achieved by edging the upper beam; - it is possible in a simple manner to design an upper beam field such that it kinks as the first part on an incorrect crane operation during the crane assembly, for example, so that the most inexpensive boom part fails first; and - an extremely slim upper beam section and a lateral wind attack surface that is small for this reason can be achieved so that a relatively smaller slewing gear drive is sufficient.

Claims (10)

A crane, in particular a turret, with at least one lattice beam (7) comprising several longitudinal bars (8, 9) connected to each other via transverse and / or diagonal struts (10), wherein at least one of the longitudinal booms ( 8) has a boom cross section that varies over the boom length, and / or different boom cross sections in different grid fields (11, 12, 13), wherein the at least one longitudinal boom (8) has weld seamless transitions between boom sections with different boom cross sections, characterized in that the at least one longitudinal boom (8) in the lattice fields (11, 12, 13) between connected transverse and / or diagonal struts (10) has different beam cross sections, each adapted to the tensile forces of the particular lattice field (11, 12, 13) , where the beam cross section remains substantially constant over the beam length in a particular grid field (11,12,13). A crane according to the preceding claim, wherein the at least one longitudinal boom (8) forms the upper boom of an extension member and / or a main boom of the lattice beam (7), which is predominantly subjected to drag only. A crane according to any one of the preceding claims, wherein said boom cross section (8) cross-section in at least a portion of the lattice beam (7) decreases from lattice field to lattice field in one direction, especially in a projecting tip portion towards the excellent end. The crane according to one of the preceding claims, wherein the longitudinal boom (8) is formed as a band steel part and / or full material profile part with approx. square cross section. The crane according to the preceding claim, wherein the longitudinal boom with its short main axis is oriented in a vertical plane. A crane according to any one of the preceding claims, wherein said at least one longitudinal boom (8) is made of a preferably high-strength steel. Crane according to one of the preceding claims, wherein the at least one longitudinal boom (8) has a boom width (B1, B2, B3) which changes in the longitudinal direction of the boom at constant boom height (H). A crane according to any one of the preceding claims, wherein the longitudinal boom (8) of at least one connecting point (14, 15, 16, 17) of a transverse and / or diagonal strut (10) comprises a profile extension (18) from which the cross section of the boom decreases on both sides in the longitudinal direction of the boom. Crane according to the preceding claim, wherein the longitudinal boom (8) towards the profile extensions (18) has arms with incisions, especially rounded contour transitions. A crane according to any one of the preceding claims, wherein the at least one longitudinal boom (8) has at least a single angular and / or bent longitudinal axis, wherein a weld seamless transition is provided between the boom sections that are angular or bent relative to the each other.