Heavy lifting structure

Abstract

The utility model provides a heavy hoist structure, including as the base's lower frame module and parallel to lower frame module and as the top seat's upper frame module, and the frame assembly is formed through a plurality of stand columns between lower frame module and upper frame module, the centre of upper frame module is equipped with the umbrella rib shape reinforcing module, the umbrella rib shape reinforcing module includes a plurality of support beams, the first end of support beam is connected and forms the first support point, and the second end of support beam is connected with the angle and / or side of upper frame module and forms the second support point, and the first support point and second support point are in the same plane, the first reinforcement of same length is fixed on each angle of upper frame module, and the end of first reinforcement is equipped with the lifting ring for hoist, and the lifting ring is located the center of upper frame module above, the utility model discloses heavy hoist structure adopts the modularization splicing structure, and the handling is convenient, and the structural strength is high, and the deformation resistance and the bearing capacity are strong, hoist is safe, reliable, and convenient for transportation, and the transportation difficulty and cost are reduced.

Description

Technical Field

[0001] This utility model relates to a hoisting structure, and more particularly to a heavy-duty hoisting structure. Background Technology

[0002] In the field of engineering hoisting, heavy-duty frame hoisting structures are one of the most widely used hoisting systems. These structures typically consist of a frame system with multiple beams and columns to secure heavy hoisting equipment such as cranes. However, these structures present some significant problems in practical applications. Especially under heavy loads, the deformation of the frame becomes particularly prominent. Due to the large weight of the frame system, its rigidity is relatively weak, making it prone to localized or overall deformation under external loads and internal forces. This significantly reduces the stability and safety of the structure. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to provide a heavy-duty hoisting structure that optimizes the structural design, thereby improving the structural strength during hoisting, avoiding deformation problems, and facilitating assembly.

[0004] This utility model provides a heavy-duty hoisting structure, which includes a lower frame module as a base and an upper frame module parallel to the lower frame module and serving as a top seat. A plurality of columns are detachably installed between the lower frame module and the upper frame module to form a frame assembly. An umbrella-shaped reinforcing module is detachably installed at the center of the upper frame module. The umbrella-shaped reinforcing module includes multiple support beams. The first ends of the support beams are interconnected to form a first support point, and the second ends of the support beams are connected to a corner and / or side of the upper frame module to form a second support point. The first support point and the second support point are located in the same plane. First reinforcing bars 83 of the same length are fixed at each corner of the upper frame module. The ends of the first reinforcing bars 83 are provided with lifting rings for hoisting, and the lifting rings are located above the center of the upper frame module.

[0005] Furthermore, a first lifting eye bolt 36 is installed at each corner of the upper frame module, and the first reinforcing bar 83 is welded and fixed to the first lifting eye bolt 36.

[0006] Furthermore, the upper and lower side walls of the column are equipped with second lifting eye bolts 37, and diagonal tie bars 81 are connected between the two diagonally opposite second lifting eye bolts 37 to form an X-shaped diagonal tie reinforcement structure.

[0007] Furthermore, the support beam includes a first support beam 62 and a second support beam. The first support beam 62 is parallel to the length or width direction of the upper frame module, and its end is fixedly connected to the edge of the upper frame module. The second support beam has the same number of angles as the upper frame module. The first end of the second support beam is connected to the first support beam 62, and the second end is connected to each of the inner angles of the upper frame module.

[0008] Furthermore, the second support beam includes a first rod 63 welded and fixed to the side wall of the first support beam 62, and a second rod 64 coaxial with the first rod 63 and detachably installed at the end of the first rod 63. The tail of the second rod 64 is detachably connected to the inner corner of the upper frame module.

[0009] Furthermore, the end of the first rod 63 is provided with a sleeve part 631, and the head of the second rod 64 is provided with a sleeve hole for axial insertion of the sleeve part 631 and for limiting its position. The connection end of the first rod 63 and the second rod 64 is provided with a fixing plate 65 and is fixedly connected by bolts.

[0010] Furthermore, the length of the first rod 63 is less than the length of the second rod 64.

[0011] Furthermore, it also includes a reinforcing column 4 detachably disposed between the edges of the upper frame module and the lower frame module, the reinforcing column 4 being located on the same plane as the first support beam 62; the reinforcing column 4 is provided with a third steel bar 82, the end of the third steel bar 82 extending toward the center of the upper frame module and having a lifting ring fixed at its end.

[0012] Furthermore, the reinforcing column 4 includes a reinforcing column body 41 and a reinforcing plate 42 welded and fixed to the upper and / or lower side walls of the reinforcing column body 41. The upper and lower ends of the reinforcing column body 41 are detachably fixed to the frame assembly by bolts.

[0013] Furthermore, the lower end of the reinforcing column 4 is fixed with a lower support block 43 that can contact the bottom of the lower frame module and provide support.

[0014] Furthermore, the upper and lower ends of the reinforcing column 4 are equipped with third lifting eye bolts 44, and the third reinforcing bar 82 includes a first reinforcing bar segment 821 welded between the two third lifting eye bolts 44. The upper end of the first reinforcing bar segment 821 is bent toward the center of the upper frame module to form a second reinforcing bar segment 822, and the end of the second reinforcing bar segment 822 is provided with a lifting eye.

[0015] Furthermore, the column 3 includes a column body 31, and the lower end of the column body 31 is provided with a mounting base 32. The mounting base 32 is fixed to the side wall of the lower frame module by an angle bracket. The side wall of the mounting base 32 is provided with a second lifting eye bolt 37 for installing the inclined tie bar 81.

[0016] Furthermore, the two ends of the column are detachably connected between the upper frame module and the lower frame module by bolts.

[0017] Furthermore, the lower frame module includes two parallel lower crossbeams 1 and a lower longitudinal beam 21 disposed between the two lower crossbeams 1. The bottom of the frame assembly is provided with multiple support legs 11 and / or casters 14. The upper frame module includes two parallel upper crossbeams and an upper longitudinal beam 61 disposed between the two upper crossbeams. The upper crossbeam is formed by splicing multiple crossbeam bodies, and the upper crossbeam and the upper longitudinal beam are detachably connected by bolts.

[0018] Furthermore, a V-shaped reinforcing rod 12 is provided at the bottom of the upper frame module and the lower frame module. The reinforcing rod is strip-shaped and is located at the bottom of the side of the upper frame module and the lower frame module, with its length direction parallel to the length direction of the corresponding side.

[0019] Furthermore, the upper frame module and / or the lower frame module are detachable structures.

[0020] This utility model of a heavy-duty lifting structure adopts a detachable modular design, enabling rapid assembly and convenient loading and unloading, facilitating production, transportation, and assembly, and significantly reducing processing difficulty and transportation costs. Through modular structural design and optimized stress network design, it provides an efficient and reliable solution for heavy-duty lifting structures. The umbrella-shaped reinforcing module and the upper frame module are coplanar to form a three-dimensional stress network, which, together with the support blocks under the reinforced columns, fills the weak areas of the lower frame module, greatly improving structural strength and bending resistance, and avoiding dents or deformations caused by local stress concentration. The bottom is equipped with casters to facilitate the movement and positioning of the frame assembly, and short-distance movement does not require lifting equipment. The lifting function adopts a distributed lifting point structure with four corners and a center. The rigid connection between the first and third reinforcing bars ensures synchronous stress at the lifting points, improving lifting stability and reliability, and preventing tilting. This utility model of a heavy-duty lifting structure adopts a modular splicing structure, which is convenient for loading and unloading, has high structural strength, strong resistance to deformation and load-bearing capacity, and ensures safe and reliable lifting, while also facilitating transportation and reducing transportation difficulty and costs. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the heavy-duty hoisting structure of this utility model;

[0022] Figure 2 This is a schematic diagram of the steel reinforcement arrangement of the heavy lifting structure of this utility model;

[0023] Figure 3 This is an exploded structural diagram of the heavy lifting structure of this utility model;

[0024] Figure 4 for Figure 1 Enlarged view of section A in the middle;

[0025] Figure 5 This is a schematic diagram of the installation of the column of the heavy lifting structure of this utility model;

[0026] Figure 6 for Figure 1 Enlarged view of section B in the middle;

[0027] Figure 7 This is a schematic diagram of the installation of the reinforcing plate in the heavy-duty hoisting structure of this utility model;

[0028] Figure 8 This is a schematic diagram of the installation of the lower support block of the heavy-duty hoisting structure of this utility model;

[0029] Figure 9 for Figure 1 Enlarged view of section C;

[0030] Figure 10 This is a schematic diagram of the umbrella-shaped reinforcing module of the heavy-duty hoisting structure of this utility model;

[0031] Figure 11 This is a schematic diagram of the installation of the fixing plate of the heavy lifting structure of this utility model;

[0032] Figure 12 for Figure 1 Enlarged view of section D in the middle;

[0033] Figure 13 for Figure 3 Enlarged view of section E in the middle.

[0034] In the diagram: 1. Lower crossbeam, 11. Support leg, 12. Reinforcing rod, 14. Moving wheel, 21. Lower longitudinal beam, 3. Column, 31. Column body, 32. Mounting base, 33. Angle bracket, 36. First lifting eye bolt, 37. Second lifting eye bolt, 4. Reinforcing column, 41. Reinforcing column body, 42. Reinforcing plate, 43. Lower support block, 44. Third lifting eye bolt, 5. Upper crossbeam, 51. Crossbeam body, 61. Upper longitudinal beam, 62. First support beam, 63. First rod body, 631. Connecting part, 64. Second rod body, 65. Fixing plate, 81. Diagonal tie bar, 82. Third reinforcement bar, 821. First reinforcement bar segment, 822. Second reinforcement bar segment, 83. First reinforcement bar. Detailed Implementation

[0035] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0036] See Figures 1-13 This utility model provides a heavy-duty hoisting structure, which includes parallel lower frame modules and upper frame modules. The lower frame module serves as a base and is located at the lower end, while the upper frame module serves as a top seat and is located at the upper end. The lower frame module and the upper frame module are connected by several columns to form a frame assembly. An umbrella-shaped reinforcing module is detachably installed at the center of the upper frame module. This umbrella-shaped reinforcing module includes multiple support beams. The number of support beams is the same as the number of angles and / or sides of the upper frame module. That is, the number of support beams can be the same as the number of angles, or the same as the number of sides, or the same as the number of sides and angles of the upper frame module. The first ends of the support beams are interconnected, forming a... The first support point is formed, and the second end of the support beam is connected to the corner and / or side of the upper frame module to form the second support point. That is, the second end of the support beam is connected to the corner of the upper frame module, or to the side of the upper frame module, or to both the corner and the side of the upper frame module. The first support point and the second support point are located in the same plane, that is, the umbrella-shaped reinforcing module and the upper frame module are located in the same plane. The first steel bar 83 of the same length is fixed at each corner of the upper frame module. The first steel bar 83 faces the center direction of the upper frame module and is inclined as a whole. A lifting ring (not shown in the figure) is provided at its end for hoisting. Each lifting ring is located above the center of the upper frame module and can be hung on the same hook to realize hoisting.

[0037] This application incorporates an umbrella-shaped reinforcing module at the center of the upper frame module, forming a three-dimensional force network and enhancing structural rigidity; the umbrella-shaped reinforcing module is umbrella-shaped, see reference. Figure 1 , Figure 3 and Figure 10 The support beams transfer the load of the upper frame module from the corners to the center, dispersing stress and preventing dents or fractures caused by localized stress concentration. The connection positions of the support beams can be adjusted according to the internal layout of the frame assembly, such as connecting to corners or edges, making them compatible with different types of internal structures of the frame assembly and highly adaptable. The support components are coplanar with the upper frame module, forming an integrated support net structure, which greatly improves the frame's resistance to deformation. Each corner of the upper frame module is equipped with a first reinforcing bar, and a lifting ring is set at its end. The reinforcing bar has a fixed length and no tensile elasticity, which ensures that the lifting points are subjected to synchronous force, avoids the shift of the lifting center of gravity caused by the elastic elongation of the wire rope, and eliminates the tilting or swaying of the frame assembly. The reinforcing bars are fixed to the frame, forming a rigid connection, which directly transfers the lifting tension to the frame assembly, avoiding localized stress concentration caused by the soft connection of the wire rope, and ensuring that the frame is evenly stressed during lifting. Through the above structural settings, this application effectively improves the stability and safety during the lifting process, ensures the accurate positioning and smooth operation of the frame assembly during lifting, reduces the risk of structural deformation, and extends the service life of the equipment.

[0038] The aforementioned umbrella-shaped reinforcing module adopts a detachable structure. Specifically, it is fixed to the upper frame module with bolts, which facilitates assembly and reduces production and transportation costs.

[0039] To facilitate the loading and unloading of the first reinforcing bar 83, in this application, first lifting eye bolts 36 are installed at each corner of the upper frame module. The first lifting eye bolts 36 are set upwards and are detachably connected to the frame assembly. Preferably, they are set at the top of the column, and the first reinforcing bar 83 is welded and fixed to the first lifting eye bolts 36. The first reinforcing bar 83 is welded to the lifting eye bolts, which can be prefabricated in the factory. On-site, only the prefabricated lifting eye bolts need to be fixed to the upper frame module, which greatly shortens the installation and disassembly time. The lifting eye bolts and the upper frame module are detachably connected. During transportation, the lifting eye bolts and reinforcing bar components can be packaged separately to reduce the overall volume of the frame, which is especially suitable for the cross-regional long-distance transportation needs of the frame assembly. The lifting eye bolts are rigidly connected to the upper frame module through threads, and the reinforcing bars are welded to the lifting eye bolts to form an integrated structure. Compared with the soft connection of traditional wire ropes, this improves the connection strength, effectively transmits the lifting tension, and avoids local stress concentration. In this application, the lifting eye bolts are set at the top of the column, which can directly transmit the lifting tension to the column and avoid the upper frame module bearing the load alone.

[0040] To further enhance structural strength, this application includes second eye bolts 37 installed on the upper and lower side walls of the column. Diagonal tie bars 81 are connected between two diagonally opposite second eye bolts 37, forming an X-shaped diagonal bracing structure. When the frame is subjected to torsional force, the diagonal tie bars generate a counter-tension, counteracting the torsional tendency, preventing frame twisting, ensuring the overall structural strength of the frame, and preventing deformation. The diagonal tie bars are fixed by the second eye bolts, enabling quick assembly and disassembly, modular assembly, and high flexibility. In this embodiment, the aforementioned X-shaped diagonal bracing structure is located at the long side end of the frame assembly.

[0041] The support beams in this embodiment include a first support beam 62 and a second support beam. The first support beam 62 is parallel to the length or width direction of the upper frame module, and its end is fixedly connected to the edge of the upper frame module, preferably perpendicular to the edge of the upper frame module. The second support beam has the same number of angles as the upper frame module. The first end of the second support beam is fixedly connected to the first support beam 62, and its second end is connected to each inner corner of the upper frame module. The first support beam is parallel to the length or width direction of the upper frame module, forming a transverse or longitudinal main support that evenly transmits the load of the upper frame module along its edge. The second support beam connects the first support beam to the inner corner of the upper frame module, forming a radial secondary support that further disperses the load of the main support to the corners of the frame, avoiding depressions or fractures caused by local stress concentration. The combination of the two forms a three-dimensional force network of main and secondary supports, which greatly improves the deformation resistance of the upper frame module.

[0042] The aforementioned second support beam includes a first rod 63 and a second rod 64. The first rod 63 is welded and fixed to the side wall of the first support beam 62. The second rod is coaxial with the first rod 63 and is detachably installed at the end of the first rod 63. The tail of the second rod 64 is connected to the inner corner of the upper frame module. In this embodiment, it is detachably connected to the inner corner of the upper frame module by bolts, and the length of the first rod 63 is less than the length of the second rod 64. This allows the umbrella-shaped reinforcing module to form a reinforcing module and be detachably installed on the frame assembly. The above structure facilitates the quick installation and removal of the umbrella-shaped reinforcing module, while reducing the volume and facilitating transportation.

[0043] Specifically, a sleeve 631 is provided at the end of the first rod 63, and a sleeve hole is provided at the head of the second rod 64. The sleeve 631 can be axially inserted into the through hole and achieve axial and radial limiting. A fixing plate 65 is provided at the connection end of the first rod 63 and the second rod 64, and the connection is fixed by bolts. Specifically, there are two fixing plates 65, which are arranged one above the other. The fixing plates have mounting holes, and the side walls of the first rod and the second rod also have corresponding mounting holes. The bolts pass through the upper fixing plate, the rod and the lower fixing plate in sequence and are connected to the nut to achieve a fixed connection between the first rod and the second rod. Through the above structure, the connection structure is stable and reliable, and easy to disassemble and assemble, and easy to maintain and replace. The cooperation between the fixing plates and the bolts achieves double-sided clamping, which effectively enhances the shear and tensile strength of the connection part and avoids loosening caused by vibration or load fluctuation.

[0044] To further enhance structural strength, a reinforcing column 4 is included. The reinforcing column 4 is positioned between the edges of the upper and lower frame modules. In this embodiment, the reinforcing column 4 is positioned at one end of the long side, specifically at the center of the long side. The reinforcing column 4 and the first support beam 62 are located on the same plane. A third reinforcing bar 82 is provided on the reinforcing column 4. The end of the third reinforcing bar 82 extends towards the center of the upper frame module, and a lifting ring is fixed at its end as a lifting end. The lifting ring at the end of the third reinforcing bar 82 forms a distributed lifting system with four corners and a center, preferably four corner lifting ends. The reinforcing column 4 serves as the load-bearing carrier for the central lifting, connecting the upper and lower frame modules. It can disperse the tension at the lifting point, avoid stress concentration, and improve structural strength and load-bearing capacity. At the same time, the reinforcing column 4 connects the center of the long side of the upper and lower frame modules, forming a vertical and horizontal support structure on the same plane as the first support beam, improving the structural strength of the long side in both horizontal and vertical directions, and effectively preventing frame deformation.

[0045] Specifically, third lifting eye bolts 44 are installed at the upper and lower ends of the reinforcing column 4. The third reinforcing bar 82 includes a first reinforcing bar segment 821 welded between two third lifting eye bolts 44. The upper end of the first reinforcing bar segment 821 is bent towards the center of the upward frame module to form a second reinforcing bar segment 822. The end of the second reinforcing bar segment 822 is provided with a lifting eye. The first reinforcing bar segment 821 of the third reinforcing bar 82 is welded between the third lifting eye bolts 44 at the upper and lower ends of the reinforcing column to form a composite support of the reinforcing column and vertical reinforcing bar. During hoisting, stress concentration caused by single-point connection to the reinforcing column can be avoided, the overall structural strength and bending resistance of the frame can be improved, and deformation can be ensured during hoisting.

[0046] In this embodiment, the reinforced column 4 reinforces the column body 41. Reinforcing plates 42 are attached and fixed to the upper and lower side walls of the reinforced column body 41 to form a reinforced structure. The upper and lower ends of the reinforced column body 41 are detachably fixed to the frame assembly by bolts. By setting reinforcing plates 42 at the upper and lower ends of the reinforced column body, the structural strength at both ends of the reinforced column can be improved. As the connecting end, it connects with the upper and lower frame modules, which can improve the connection strength and avoid deformation or breakage of the connection part due to stress concentration, thus ensuring the structural stability and safety during hoisting and use.

[0047] A lower support block 43 is fixed at the lower end of the reinforcing column 4. This support block can contact the bottom of the lower frame module, thereby supporting the lower frame module. The center of the long side of the lower frame module is a weak area. The lower support block at the lower end of the reinforcing column 4 directly contacts the bottom of the lower frame module, forming a vertical support point. This can effectively prevent the complete deformation of the long side of the lower frame module, while reducing the stress concentration of the bolts between the lower end of the reinforcing column and the lower frame module, thus improving the structural stability.

[0048] In this embodiment, the column 3 includes a column body 31. The lower end of the column body 31 is provided with a mounting base 32. The mounting base 32 is fixed to the side wall of the lower frame module by angle brackets 33 and bolts. That is, the column is detachably installed between the upper frame module and the lower frame module. A second lifting eye bolt 37 is provided on the side wall of the mounting base 32, which is used to install the diagonal reinforcing bar 81. It forms a modular structure, which facilitates production and loading and unloading operations.

[0049] In this application, the upper frame module and the lower frame module are rectangular structures, forming a rectangular frame assembly. The upper frame module and the lower frame module are detachable splicing structures. Specifically, the lower frame module includes two parallel lower crossbeams 1 and a lower longitudinal beam 21 disposed between the two lower crossbeams 1. Multiple support legs 11 and casters 14 are provided at the bottom of the lower frame module. The support legs 11 are used for support, and the casters 14 are used for short-distance movement and position adjustment. The casters are omnidirectional load-bearing casters, which are installed at the lower end of the lower frame module. Specifically, they are installed on each side of the lower frame module, with at least two casters on each side, and they have a braking function. The upper frame module includes two parallel upper crossbeams 5 and an upper longitudinal beam 61 disposed between the two upper crossbeams 5. The upper crossbeams are spliced ​​together by multiple crossbeam bodies 51, and their splicing structure is the same as that of the umbrella-shaped reinforcing module. The upper crossbeams 5 and the upper longitudinal beams 61 are detachably connected by angle brackets and bolts.

[0050] To further enhance structural strength, in this embodiment, a V-shaped reinforcing bar 12 is provided at the bottom of the sides of the upper frame module and the lower frame module to further enhance bending strength. Specifically, it is fixed to the bottom surface of the crossbeam or longitudinal beam by welding, and its length direction is parallel to the length direction of the crossbeam or longitudinal beam.

[0051] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A heavy-duty hoisting structure, characterized in that: The system includes a lower frame module serving as a base and an upper frame module parallel to the lower frame module and serving as a top support. Several columns are detachably installed between the lower frame module and the upper frame module to form a frame assembly. An umbrella-shaped reinforcing module is detachably installed at the center of the upper frame module. The umbrella-shaped reinforcing module includes multiple support beams. The first ends of the support beams are interconnected to form a first support point, and the second ends of the support beams are connected to the corners and / or sides of the upper frame module to form a second support point. The first support point and the second support point are located in the same plane. First steel bars of the same length are fixed at each corner of the upper frame module. The ends of the first steel bars are provided with lifting rings for hoisting. The lifting rings are located above the center of the upper frame module.

2. The heavy-duty hoisting structure as described in claim 1, characterized in that: The upper frame module is equipped with first lifting eye bolts at each corner, and the first reinforcing bar is welded and fixed to the first lifting eye bolts.

3. The heavy-duty hoisting structure as described in claim 1, characterized in that: The upper and lower side walls of the column are equipped with second lifting eye bolts, and diagonal reinforcing bars are connected between the two diagonally opposite second lifting eye bolts to form an X-shaped diagonal bracing structure.

4. The heavy-duty hoisting structure as described in claim 1, characterized in that: The support beam includes a first support beam and a second support beam. The first support beam is parallel to the length or width direction of the upper frame module, and its end is fixedly connected to the edge of the upper frame module. The second support beam has the same number of angles as the upper frame module. The first end of the second support beam is connected to the first support beam, and the second end is connected to each of the interior angles of the upper frame module.

5. The heavy-duty hoisting structure as described in claim 4, characterized in that: The second support beam includes a first rod welded and fixed to the side wall of the first support beam and a second rod coaxial with the first rod and detachably installed at the end of the first rod. The tail of the second rod is detachably connected to the inner corner of the upper frame module.

6. The heavy-duty hoisting structure as described in claim 4, characterized in that: It also includes a reinforcing column detachably disposed between the edges of the upper frame module and the lower frame module, the reinforcing column being located on the same plane as the first support beam; the reinforcing column is provided with a third steel bar, the end of the third steel bar extending toward the center of the upper frame module and having a lifting ring fixed at its end.

7. The heavy-duty hoisting structure as described in claim 6, characterized in that: The lower end of the reinforcing column is fixed with a lower support block that can contact the bottom of the lower frame module and provide support.

8. The heavy-duty hoisting structure as described in claim 6, characterized in that: The upper and lower ends of the reinforcing column are equipped with third lifting eye bolts. The third reinforcing bar includes a first reinforcing bar segment welded between the two third lifting eye bolts. The upper end of the first reinforcing bar segment is bent toward the center of the upper frame module to form a second reinforcing bar segment. The end of the second reinforcing bar segment is provided with a lifting eye.

9. The heavy-duty hoisting structure as described in claim 1, characterized in that: The upper frame module and / or the lower frame module are detachable structures.

10. The heavy-duty hoisting structure as described in claim 1, characterized in that: The bottom of the frame assembly is provided with multiple feet and / or casters.

Images