Disassemblable grid section for crane boom

Abstract

Disassemblable grid section (1; 100) for a crane boom comprising two corner post side sections (2; 30), each consisting of at least two corner posts (5; 31) which are firmly welded together by means of several connecting rods (6, 7; 32, 33), and at least one transverse connection (3, 4; 40) connecting the corner post side sections (2; 30), which is bolted to the corner post side sections (2; 30), characterized in that the working height of a grid section (1; 100) corresponds essentially to the transport width of a transport unit formed from the individual parts of the grid section (1; 100) and that the corner post side sections (2; 30) are rotated in the transport unit by 90° about the longitudinal axis of a corner post (5; 31) relative to the assembly position.

Description

[0001] The invention relates to a demountable grid section for a crane boom.

[0002] Disassemblable lattice sections for crane booms are generally known from the prior art. For example, DE 10 2013 205 173 A1 discloses a lattice boom element, a lattice boom with at least one such lattice boom element, and a crane with such a lattice boom. Furthermore, US 2011 / 0 284 490 A1 describes a crane boom with multiple main girders. Without changing the size of the individual boom sections during transport, the cross-sectional area of ​​the main girder is increased, and the integral stiffness of the boom is enhanced by increasing the number of main girders.

[0003] Non-disassemblable, cuboid lattice sections used for lattice boom cranes generally have a width of 3 to 4 meters, as these dimensions represent typical limits for economical transport of the sections. However, a greater lattice section width is desirable with regard to the achievable stiffness of the crane boom, since the greater width of the lattice section increases the resulting area moment of inertia and reduces lateral boom deflection.

[0004] Therefore, solutions are being sought for large cranes to enable the use of the largest possible, rigid mesh sections with widths exceeding the aforementioned 4 meters, while still allowing for economical transport. Partial solutions have already emerged in the prior art, particularly those proposing divisible mesh sections. Such mesh sections consist of individual bars that can be bolted together to assemble the mesh section. Mesh sections are also known that consist of two individual segments, each representing a three-dimensional support structure. These individual segments are then connected to each other via diagonal tubes. However, both of these solutions require optimization with regard to both transport and rapid assembly.

[0005] As an alternative to enlarging the grid sections, the construction of cranes with parallel crane towers is known.

[0006] The object of the present invention is to provide an alternative solution for a demountable grid section that has economically viable transport dimensions, but can be assembled into a large grid section as quickly and easily as possible at the place of use.

[0007] This problem is solved by a demountable grid piece according to the features of claim 1. Advantageous embodiments of the grid piece are the subject of the dependent claims.

[0008] Starting from a disassemblable grid piece known from the prior art, comprising two corner post side parts, each consisting of at least two corner posts, the invention provides that the working height of a grid piece essentially corresponds to the transport width of a transport unit formed from the individual parts of the grid piece and that the corner post side parts are rotated by 90° around the longitudinal axis of a corner post relative to the assembly position in the transport unit.

[0009] To form a transport unit, several disassembled components, such as corner side panels, cross connectors, and / or mesh panels, are stacked on top of each other or folded together to save space. Compared to the assembly / disassembly orientation, the corner post side panels are rotated 90° around the longitudinal axis of a corner post to form the transport unit, according to the invention. This ensures that the height of the assembled mesh panel corresponds to the transport width of the transport unit during operation. For the assembly process, the corner post side panels are rotated 90° around the longitudinal axis of a corner post from their position within the transport unit to the required assembly position.

[0010] In its assembled working configuration, the mesh panel is significantly larger than the economically viable and, in some countries, permissible transport dimensions. However, for road transport, the mesh panel can be easily disassembled by separating the two corner post side sections by loosening the bolt connection to the cross member. Specifically, after loosening the bolt connection, the corner post side sections are rotated 90 degrees around their longitudinal axis so that they can be stacked on top of each other. The cross member, or its individual components, can ideally be stored on or between the stacked corner post side sections. In its disassembled transport state, the entire mesh panel does not exceed the permissible transport widths and heights. It is crucial that the height of the corner post side sections in their working state, i.e., the distance between the corner posts, remains within the transport width.The individual parts of a disassembled grid section preferably form a transport unit in the transport state.

[0011] The cross connection includes, for example, several diagonal bars that can be bolted to the corner post side pieces. The diagonal bars can be bolted to the corner posts of the corner post side pieces at their ends.

[0012] Additionally or alternatively, the cross connection can also include at least two flat mesh panels that can be bolted vertically to the corner post side members. These mesh panels form the side surfaces of the assembled mesh section. Each of these mesh panels is preferably bolted to the end regions of the corner post side members. This bolting allows the mesh panels to be either removed for transport or folded against the corner post side member. The outer contour of the mesh section is thus formed by both corner post side members and both mesh panels. Each of these mesh panels can, for example, consist of two parallel longitudinal struts connected to each other by diagonal bars and / or posts, and in particular, welded together.

[0013] The corner post side sections themselves can be equipped with at least one connecting bracket. Such a connecting bracket serves to secure individual, stacked corner post side sections to one another during transport. This connecting bracket is preferably arranged on a corner post of the corner post side sections, and in particular, welded on vertically. Preferably, at least two connecting brackets are provided per corner post side section or per corner post. Ideally, the connecting brackets are designed as so-called twistlock brackets, which are already known from the container industry.

[0014] According to a further advantageous embodiment of the invention, the at least two corner post side sections can also be designed as three-dimensional corner post side sections. The three-dimensional extension is achieved by four corner posts each, which are connected to one another by means of suitable connecting rods, in particular posts and / or diagonals, to form a three-dimensional cuboid structure. Accordingly, the corner post side sections themselves are designed as narrow, conventionally constructed grid sections. The corner posts are welded firmly to one another by means of the connecting rods. Preferably, immediately adjacent corner posts, i.e., those lying in a common plane, are welded firmly to one another by means of connecting rods, preferably diagonal rods and / or posts.

[0015] It is advantageous if the two spatial corner post side sections are bolted or boltable to each other by means of an X-shaped cross connection. According to a preferred embodiment, the X-shaped cross connection can be formed by a pair of intersecting diagonal bars, the diagonal bars preferably being connected to each other at the point of intersection. Preferably, these cross centrally at approximately half the distance between the connected corner post side sections. Such an X-shaped cross connection serves to increase the torsional stiffness of the grid section. The diagonal connections of the X-shaped cross connection significantly increase the torsional stiffness compared to two individual, unconnected corner post side sections. The diagonals of the X-shaped cross connection prevent twisting and displacement of the two corner post side sections relative to each other (the diagonals absorb tension and compression).

[0016] It is also conceivable that several such pairs of intersecting diagonal bars are used for the X-shaped cross connection. Preferably, these pairs lie parallel to each other between the corner post side sections to be joined. Adjacent pairs of intersecting diagonal bars can be welded together via one or more bars. The diagonal connections can be designed as a planar truss. The buckling length of a single narrow corner post side section corresponds to the entire length of the grid section. Due to the truss design, which is based on a conventional grid section, the corner post side section is compression-resistant over its entire length.

[0017] According to a particularly advantageous embodiment, the intersecting diagonal bars can be pivoted relative to each other at the intersection point about at least one pivot axis. This pivot axis is, in particular, perpendicular to the longitudinal direction of the diagonal bars. The pivot axis makes it possible to fold the X-shaped cross-connection for transport in a space-saving manner, especially such that the diagonal bars lie almost parallel to each other, and preferably adjacent to each other.

[0018] In addition to this X-shaped cross connection, the two spatial corner post side sections can be connected to each other by means of one or more mesh panels. The mesh panels can be bolted to the ends of the corner post side sections. Here, too, the mesh panels can be constructed from two parallel longitudinal bars, as already described above, which are welded firmly to each other by means of diagonal bars and / or posts. The mesh panels bolted to the end regions of the corner post side sections, together with the corner post side sections, form the outer contour of the resulting mesh section. Preferably, the ends of the X-shaped cross connection are connected to the end regions of the mesh panels or the corner post panels, i.e., bolted.

[0019] Ideally, the mesh panels are bolted to at least one corner post side piece in a pivoting manner. This allows the mesh panels to be folded flat against the corresponding corner post side pieces for space-saving transport.

[0020] According to another advantageous embodiment, a transport unit consists of all the individual parts of the disassembled grid piece.

[0021] The bolting during transport is preferably carried out at the aforementioned connecting brackets or twistlock brackets. This enables a cost-effective connection of the corner post side parts and the central grid section 40. The aforementioned brackets can also be used for stacking several grid sections.

[0022] In addition to the lattice element according to the invention, the present invention also relates to a crane, in particular a mobile crane, with at least one lattice element according to the invention. The crane preferably comprises a tower and / or lattice boom constructed from several of the lattice elements according to the invention. The crane is therefore characterized by the same advantages and properties as the lattice element according to the invention; to avoid repetition, reference is made to the preceding descriptions.

[0023] The invention further comprises a method for assembling a grid element according to the invention. For an embodiment of the grid element with individual diagonal bars connecting the corner post side parts, at least the corner post side parts, and preferably all individual components of the grid element, are transported stacked on top of each other. At the installation site, the grid element is then assembled using the following process steps: Erecting a corner post side piece from its transport position by standing it upright, i.e., rotating it 90 degrees around its longitudinal axis, and fixing the corner post side piece to an erected mounting frame or mounting bracket. In this erected position, the corner post side piece rests on the ground along the length of a corner post or is fixed in the mounting bracket, particularly near the ground, e.g., bolted in place.

[0024] In the next step, the second corner post side piece is erected in the same manner and connected to the mounting frame and / or mounting bracket. Using the mounting frame, the two corner post side pieces can be aligned at a precisely defined distance from each other, which is specifically tailored to the dimensions of the grille panels.

[0025] Next, the first mesh panel is assembled or unfolded and connected or bolted to the opposite corner post side piece. Since the distance between the two corner post side pieces was previously defined using the mounting frame, at least one mesh panel and the corner post side pieces are immediately in the bolting position. After bolting, at least one diagonal bar connecting the corner post side pieces is inserted for stabilization.

[0026] The second mesh panel can then be unfolded or mounted and bolted to the opposite corner post side piece. As explained above, the individual mesh panels can either be completely removed from the corner post side pieces, or they can remain bolted to at least one corner post side piece and, for transport purposes, be folded against the corner post side piece around the existing bolt connection.

[0027] According to an advantageous embodiment, after the second grid panel has been installed, all diagonal bars connecting the two corner post side sections can be mounted. Preferably, all diagonal bars are first inserted between the two corner posts that rest on or are located near the ground. Then, the diagonal bars connecting the two upper corner posts of each corner post side section can be mounted. After all diagonal bars have been mounted, a walkway plate can optionally be placed on top of them.

[0028] In one embodiment of the mesh panel with three-dimensional corner post side pieces and an X-shaped cross brace, the assembly process is similar with minor variations. Here, individual components of the mesh panel are also stacked on top of each other for transport purposes. The first step involves erecting the X-shaped cross brace by rotating it 90 degrees around its longitudinal axis. After positioning the X-shaped cross brace on an assembly frame placed on the floor, the individual mesh panels bolted to the X-shaped cross brace can be unfolded. Following this, the first and second corner post side pieces can be successively rotated 90 degrees and bolted to the X-shaped cross brace.

[0029] Further advantages and features of the invention will be explained in more detail below with reference to the exemplary embodiments shown in the figures. The figures show: Fig. 1a-1d: different perspective views of the grid piece according to the invention in a first embodiment, Fig. 2a, Fig. 2b, Fig. 2c: three representations of the stacked subcomponents of the disassembled lattice piece according to the Fig. 1a-1d, Fig. 3a-3d: a chronological representation of the assembly steps required for the assembly of the grid piece according to the Fig. 1a to 1d, Fig. 4a-4c: different perspective views of the grid piece according to a second embodiment according to the invention, Fig. 5a, Fig. 5b: two representations of the stacked subcomponents of the disassembled lattice piece according to the Fig. 4a-4c and Fig. 6a-6d: a chronological representation of the assembly steps required for the assembly of the grid piece according to the Fig. 4a to 4c,

[0030] The Fig. 1, Fig. 2 to Fig. Reference 3 refers to a first embodiment of the grid element according to the invention. Such a grid element 1 consists of two individual corner post side parts 2 or corner post side plates 2, which are connected by individual diagonals 4 and planar vertical grid plates 3. Fig. Figure 1a shows a perspective side view of grid piece 1, Fig. 1b a side view of grid piece 1, Fig. 1c a top view of the grid piece 1 and Fig. 1d a front view of the grid piece 1.

[0031] Each corner post side section 2 comprises two corner posts 5, each with polygonal or oval cross-sections. The two corner posts 5 are welded together at their ends via a vertical post 6. The diagonal bars 7, arranged between the two posts 6 and connecting the corner posts 5, are also welded to the corner posts 5. Connecting elements 8 for finger-fork connections are located at the ends of the corner posts 5 to assemble the lattice sections for the crane or crane boom.

[0032] The two corner post side parts 2 are connected to each other via a detachable cross connection in order to give the shape of the assembled grid piece according to Fig. 1a. The cross connection consists of several diagonal bars 4 and planar vertical grid discs 3. In the illustrated embodiment, the opposing corner posts 5 of the corner post side parts 2 are connected by three diagonal bars 4a and 4b respectively, the diagonal bars of the upper corner posts 5 in the drawing being designated 4a and the lower diagonal bars for connecting the lower corner posts 5 being designated 4b. The diagonal bars are bolted to bolt receptacles 5a. The bolt receptacle 5a can be located on the corner post 5 as shown, or alternatively on the fork 8 or the post 6.

[0033] The flat grid panels 3 each consist of two parallel longitudinal bars 9, which are welded together at each end via a crossbar 10 and diagonal bars 11 arranged between them. The ends of the longitudinal bars 9 can also be bolted to suitable bolt receptacles 5a on the corner posts 5. For transport, the grid panels 3 remain bolted to a corner post side piece 2 and are folded against it around the existing bolt connection.

[0034] For efficient transport, the corner post side pieces 2 have connecting brackets 12, preferably twistlock brackets (so-called "container corners"), with which the corner post side pieces 2 can be stacked on top of each other and connected. The connection is preferably made with twistlocks, which are also used to connect shipping containers. This is shown in Fig. 2b.

[0035] The transport width b TransportThe height of grid section 1 in the transport state corresponds to the grid section height in the operating state. The components remain within the permissible transport dimensions in the transport state. This is evident in the Fig. Figure 2a shows two corner stem side parts 2 stacked on top of each other. The distance between the two parallel corner stems 5 of a corner stem side part 2 is here referred to as the transport width b. Transport designated.

[0036] The following will be based on the representations of the Fig. Sections 3a to 3d describe the basic assembly process for grid piece 1: The starting point is the transport condition according to Fig. 2c, in which several corner post side parts 2 are stacked on top of each other and connected with twistlocks to the brackets 12 located on the corner post 5. First, a mounting frame 20 is erected and connected to the ballast weight 21 to stabilize the mounting frame 20. Furthermore, individual mounting brackets 22 are set up opposite the mounting frame 20.

[0037] First, a corner post side part 2 is erected by a 90° rotation around its longitudinal axis and connected to the mounting frame 20 and a mounting bracket 22 (see. Fig. 3a). This is followed by the erection of a second corner post side section 2, also by rotating it 90° around its longitudinal axis (see. Fig. 3b). The second corner post side piece 2 is also connected to the mounting frame 20 and another mounting bracket 22, thereby stabilizing its position. The mounting frame 20 defines the distance between the corner post side pieces 2.

[0038] The first grid panel 3 can then be opened and bolted to the second corner post side piece 2 (see below). Fig. 3b). Next, at least one of the lower diagonal bars 4b is inserted using an auxiliary crane and bolted to both side parts 2 to stabilize the corner post side parts 2.

[0039] In the next step, the second grid disc 3 is unfolded and connected to the first corner stem side disc 2 (see. Fig. 3c). Then, the remaining lower diagonal bars 4b can first be inserted between the corner post side pieces 2, followed by the upper diagonal bars 4a. Finally, the walkway 13 can be placed on the upper diagonal bars 4a and the assembled grid section 2 lifted out of the mounting frame 20, 22 (see ). Fig. 3d).

[0040] The steps described above are carried out in reverse order to disassemble the grid section.

[0041] The properties of the grid element according to the invention can be summarized as follows: - Disassemblable grid section 1, which in working configuration has larger dimensions than the economical (and in some countries permissible) transport dimensions in road transport. - Two foldable flat grid discs 3 for cross-connecting the two corner stem side parts 2. - Bolt-in single diagonal bars 4 between the corner post side parts 2. - Components folded together and rotated 90° for transport. - Height of grid section 1 in working configuration smaller than permissible or economical transport width (height in operation = width in transport due to 90° rotation around the longitudinal axis) - Grid piece 1 can 1) be transported disassembled into individual parts or 2) All parts folded and stacked on top of each other for transport as a single transport unit. - The bolting of the individual corner post side parts 2 of a grid section 1 to the brackets 12 in the transport state is done with "container corners" (twistlock brackets) and twistlocks => Cost-effective connection of the corner post side parts - The consoles 12 can be used to stack multiple grid pieces 1

[0042] A second embodiment of the grid element according to the invention is described in the Fig. 4, Fig. 5 to Fig. Figure 6 shows that, in contrast to the first embodiment, this variant consists of two separate spatial corner post side parts 30, each designed as a grid element. The two corner post side parts 30 are connected by a detachable X-shaped transverse connection 40. Fig. Figure 4a shows a perspective side view of grid piece 100, Fig. 4b a side view of a corner stem side part 30 and Fig. 4c a top view of the grid piece 100.

[0043] Each corner post side section 30 comprises four corner posts 31, the spatial arrangement of which forms a cuboid. Adjacent corner posts 31 are firmly welded together by means of several diagonal bars 32, while the more widely spaced corner posts 31, here the upper and lower corner posts, are additionally connected at their ends by means of vertically positioned posts 33. Connecting elements 34 for finger-fork connections are located at the ends of the corner posts 31.

[0044] The two corner post side sections 30 are connected to each other via a detachable or foldable X-shaped cross connection 40, which is formed by two pairs 41, 42 of intersecting diagonal bars 43, 44. The ends of the diagonal bars 43, 44 are bolted to the corner posts 31 via bolt receptacles 35. Each pair 41, 42 consists of a continuous diagonal bar 43 and a two-part diagonal bar 44. The individual bars of the diagonal bar 44 are each pivotally connected to the continuous diagonal bar 43 about axes of rotation D1, D2. Two ends of each of the diagonal bars 43, 44 are connected to each other via a planar grid disc 50, the grid disc 50 being constructed analogously to the grid disc 3 of the first embodiment of the grid piece 1.The ends of the longitudinal bars of the grid disc 50 are pivotably connected to the diagonal bars 43, 44 as well as to the bolt receptacles 35 of the corner posts 31, so that the entire structure of the x-shaped cross connection 40 together with the grid discs 50 can be folded up to save space.

[0045] For transport, all components of the 100 mm grid section can be stacked on top of each other, as shown in the Fig. 5a, Fig. Figure 5b shows that the same advantages regarding transport width are achieved as already demonstrated in the first embodiment.

[0046] The individual assembly steps for constructing the grid section will be described below using the illustrations of the Fig. Sections 6a to 6d will be explained. This involves starting with a stack of individual parts according to the... Fig. 5a, Fig. 5b. The connection between the individual parts during transport is preferably made by means of twistlocks via the connecting elements 36, as in the first embodiment.

[0047] For assembly, in the first step the central X-shaped grid 40 (diagonal bars 43, 44 including the grid discs 50) is placed in the assembly position by rotating it 90° around its longitudinal axis and fixed in a mounting frame 60, which allows vertical mounting (see figure). Fig. 6a). After removing the walkways 51 from the transport position (the walkways 51 are transported either individually or in the folded grid section 100), the first hinged grid panel 50 of the central grid 40 can be unfolded around the central pivot axis D1 on the mounting frame 60 (see. Fig. 6b). Then the second hinged grid panel 50 of the central grid 40 is folded open around the central pivot axis D2 on the mounting frame 60 (see Fig. 6c).

[0048] The first corner post side piece 30 can then be erected by rotating it 90° around its longitudinal axis and bolted to the central grid 40. The same procedure is followed for the second corner post side piece 30 (see figure). Fig. 6d). The required rotation of the corner post side parts about their longitudinal axes is carried out by means of an auxiliary crane which can pick up the parts 30 via appropriately arranged lifting eyes.

[0049] Finally, the catwalk 51 is put back on and the grid piece 100 is removed from the mounting frame 60.

[0050] The advantages of the second version are comparable to those of the first version, but are listed again below: - Disassemblable grid section 100, which in working configuration is larger than the economically transportable (and in some countries permissible) transport dimensions in road transport. - Two narrow corner post side sections 30, conventionally constructed as a grid piece, consisting of four corner posts 31, fork-finger connections 34 and welded diagonals 32 and posts 33, similar to a P-bracket or a bracket with two towers. - Additional central X-shaped grid 40 to increase the torsional stiffness of the grid piece 100. - The diagonal connections of the central grid 40 significantly increase the torsional stiffness compared to two individual, unconnected corner post side sections 30. The diagonals of the central grid 40 prevent twisting and displacement of the two grid section towers relative to each other (the diagonals absorb tension and compression). - Foldable X-shaped diagonal connections 40. - The X-shaped diagonal connections 40 can be designed as a planar truss. - Due to the X-shaped grid, the free distance between two X-shaped diagonals is approximately as long as the entire grid section. Therefore, the area moment of inertia about the vertical axis of the corner post side section cross-section must be large enough to prevent buckling under compressive load during operation, despite the free buckling length between two X-shaped diagonals described above.

[0051] The high area moment of inertia required here, about the vertical axis of the corner stem side section cross-section, is achieved through the spatial design of the corner stem side section. That is, an X-shaped grid requires a very high area moment of inertia for the side panel cross-section. - X-shaped central grid as diagonal connections 40 must be made for each grid piece 100. - Components of the grid piece 100 can be folded together for transport and rotated 90° around the longitudinal axis. - Height of the grid section 100 in working configuration smaller than permissible transport width (height in operation = width in transport due to 90° rotation). - Grid piece 100 can 1) be transported disassembled into individual parts or 2) All parts can be folded and transported as a single transport unit. - The bolting in the transport state is preferably carried out on the stacking brackets 36 with “container corners” (twistlock brackets) and twistlocks => Cost-effective connection of the corner post side parts 30 and the central grid 40. - The 36 brackets can be used to stack multiple 100 grid pieces.

Claims

[1] Disassemblable lattice section (1; 100) for a crane boom comprising two corner post side sections (2; 30), each consisting of at least two corner posts (5; 31) which are firmly welded together by means of several connecting rods (6, 7; 32, 33), and at least one transverse connection (3, 4; 40) connecting the corner post side sections (2; 30), which is bolted to the corner post side sections (2; 30), characterized by , that the working height of a grid piece (1; 100) essentially corresponds to the transport width of a transport unit formed from the individual parts of the grid piece (1; 100) and that the corner post side parts (2; 30) are rotated by 90° around the longitudinal axis of a corner post (5; 31) relative to the assembly position in the transport unit. [2] Grating piece (1; 100) according to claim 1, characterized by, that the cross connection (4; 40) comprises several diagonal bars (4; 43, 44) that can be bolted to the corner post side parts (2; 30), wherein the diagonal bars (4; 43, 44) of the cross connection are preferably boltable to a corner post (5; 31) and / or post (6; 33) and / or another connecting bar (7; 32) and / or a fork-finger connection (8; 34) of the corner post side part (2; 30). [3] Grating piece (1; 100) according to claim 1 or 2, characterized by , that the cross connection (3; 50) comprises two planar grid discs (3; 50) that can be bolted vertically to the corner stem side parts (2; 30), wherein the grid discs (3; 50) are preferably bolted to the end regions of the corner stem side parts (2; 30) and form side surfaces of the grid piece (1; 100). [4] Grating piece (1; 100) according to claim 3, characterized by, that the grid panels (3; 50) comprise two parallel longitudinal bars (9) which are connected by means of diagonal bars (11) and / or posts (10), in particular are welded firmly together. [5] Grating piece (1; 100) according to one of the preceding claims, characterized by that the corner stem side parts (2; 30) each have at least one, preferably at least two connecting brackets (12; 36), in particular twistlock brackets, to be able to connect stacked corner stem side parts (2; 30) together for transport. [6] Grating piece (1; 100) according to claim 1, characterized by , that the at least two corner stem side parts (30) are spatial corner stem side parts, each comprising four corner stems (31), wherein the corner stems (31) lying in one plane are firmly welded together by means of connecting rods (32, 33), in particular diagonal rods (32) and / or posts (33). [7] Grating piece (1; 100) according to claim 6, characterized by, that the two corner stem side parts (30) are bolted together by an x-shaped cross connection (40). [8] Grating piece (1; 100) according to claim 7, characterized by , that the x-shaped cross connection (40) is formed by at least one pair (41, 42) of intersecting diagonal bars (43, 44), preferably by two pairs (41, 42) of intersecting diagonal bars (43, 44), wherein the pairs (41, 42) are parallel to each other and are ideally welded together by means of bars. [9] Grating piece (1; 100) according to claim 8, characterized by , that the intersecting diagonal bars (43, 44) are connected to each other at the intersection point in a pivotable manner about at least one pivot axis (D1; D2). [10] Grating piece (1; 100) according to one of claims 7 to 9, characterized by, that in addition to the x-shaped cross connection (40) two planar grid discs (50) bolted vertically to the corner stem side parts (30) are provided, which are bolted to the end areas of the corner stem side parts (30) and form side surfaces of the grid piece (1; 100). [11] Grating piece (1; 100) according to claim 10, characterized by , that the grid panels (50) each consist of two parallel longitudinal bars (9) which are connected by means of diagonal bars (11) and / or posts (10), in particular are welded firmly together, and / or that the grid panels (50) are bolted to the ends of the x-shaped transverse connection (40). [12] Grating piece (1; 100) according to any one of the preceding claims, characterized by , that all individual parts of a grid piece (1; 100) form a transport unit. [13] Crane, in particular mobile crane, with at least one lattice section (1; 100) according to one of the preceding claims. [14] Method for assembling a grid piece (1; 100) according to any one of the preceding claims 1 to 5 or 12 comprising the steps - Raising a corner stem plate (2) by 90° and fixing the corner stem plate to a mounting frame (20) and / or a mounting bracket (22) so that it rests on the mounting frame (20) and / or the mounting bracket (22), - Raising a second corner stem disc (2) at a 90° angle so that it rests on a corner stem (5), and connecting the corner stem disc (2) to the mounting frame (20) and / or the mounting bracket (22), - Mounting or unfolding the first grid disc (3) and connecting the grid disc (3) to the opposite corner stem disc (2), - Inserting at least one diagonal bar (4) and - Mounting or unfolding the second grid disc (3) and connecting the second grid disc (3) to the opposite corner stem disc (2). [15] Method according to claim 14, characterized by , that after the assembly of the second grid disc (3) all further diagonal bars (4a, 4b) are inserted, preferably first inserting all bars between the corner posts (5) which are resting on or near the ground, and after the insertion of the diagonal bars (4a, 4b) preferably mounting walkway plates (13) on the diagonal bars (4). [16] Method for assembling a grid piece (1; 100) according to any one of the preceding claims 6 to 12 comprising the steps: - Setting up the x-shaped cross brace (40) by rotating it about its longitudinal axis by 90°, - Positioning the x-shaped cross brace (40) in a mounting frame (60), - Opening the first and second grid discs (50), - Erect the first and second corner post side part (30) by rotating them 90° around their longitudinal axes and bolting them to the x-shaped cross brace (40).

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