A swing reset node for modular steel structure and its use method
Through the design of the swing reset node of the modular steel structure, the column components and connecting components are used, combined with prestressed steel strands and energy-consuming metal parts, the self-reset and efficient connection of the modular steel structure are achieved, the problem of construction space limitations is solved, the seismic resistance and construction efficiency are improved, and the cost of post-seismic repair is reduced.
Patent Information
- Application Number
- CN202411548325.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-01
- Publication Date
- 2025-09-02
- Estimated Expiration
- 2044-11-01
AI Technical Summary
On-site anchoring of recoverable functional devices in existing modular steel structures requires construction space and is inefficient, making it difficult to meet the needs of rapid recovery of functions.
The column components and connecting components are combined, and prestressed steel strands and energy-consuming metal parts are used to achieve a self-reset function without on-site anchoring. The tension of the prestressed steel strands and the deformation of the energy-consuming metal parts are consumed, combined with the swing reset node design of the modular steel structure.
It realizes efficient connection and self-reset of the modular steel structure without being restricted by construction space, reduces residual deformation after earthquake, reduces repair costs, and improves seismic performance and construction efficiency.
Smart Images

Figure CN119122102B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of steel structure node connection, and in particular to a swing reset node of a modular steel structure and a use method thereof. Background Art
[0002] The traditional earthquake-resistant concept aims to prevent structural collapse, but when the main load-bearing components or energy-absorbing devices of the structure produce irreversible plastic deformation, the entire structure will accumulate large residual deformations. Excessive residual displacement will increase the technical difficulty and economic burden of the post-earthquake repair work of the structure. With the increasing demand for the seismic performance of buildings and the development of the economic level, structures designed according to the traditional earthquake-resistant concept are obviously unable to meet the demand. Therefore, some scholars have proposed a new earthquake-resistant concept of recoverable function earthquake protection. Earthquake-recoverable function structure refers to a structure that can be restored to use after an earthquake without repair or with only a little repair. Its main purpose is to enable the structure to have the ability to quickly restore its use function after an earthquake, thereby reducing the impact caused by the interruption of the structure's post-earthquake function.
[0003] Recoverable functional devices generally use prestressed steel strands or other reinforcement materials to achieve self-resetting functions and have been successfully applied to general prefabricated structures. However, the anchoring of the steel strands requires construction space, and on-site anchoring is time-consuming. Due to the limitations of construction space and construction efficiency, the use of recoverable functional devices in modular steel structures still faces great challenges.
[0004] Therefore, on the basis of ensuring that the advantage of modular assembly efficiency is not affected, the development of a self-resetting device that is not restricted by construction space and does not require on-site anchoring is of great significance to the development of modular steel structures. Summary of the Invention
[0005] In response to the problems existing in the above-mentioned prior art, the present invention provides a swing reset node of a modular steel structure and a method for using the same. Through the cooperation of the column components and the connection components, self-reset is achieved while achieving the effect of not being restricted by construction space and not requiring on-site anchoring.
[0006] To achieve the above object, the present invention provides the following technical solutions:
[0007] In a first aspect, the present invention provides a swing reset node for a modular steel structure, wherein the modular steel structure has modular columns, wherein the modular columns include an upper modular column and a lower modular column, and the swing reset node includes:
[0008] Two column in-components, mounted respectively on the lower end of the upper module column and the upper end of the lower module column; and
[0009] A connecting component is provided between the two in-column components and is used to connect the two in-column components;
[0010] The connection component includes:
[0011] Prestressed steel strands, with anchors provided at both ends;
[0012] A horizontal connecting plate having a first through hole reserved thereon for the prestressed steel strand to pass through;
[0013] Two inner plug-ins are respectively arranged at the upper and lower ends of the horizontal connecting plate;
[0014] Two groups of energy-absorbing metal parts, two energy-absorbing metal parts form a group, and each group of energy-absorbing metal parts is symmetrically connected to the end side wall of each of the inner plug-in units close to the horizontal connecting plate;
[0015] One end of each of the inner plug-ins away from the horizontal connecting plate is respectively connected to an inserting plate, and a second through hole is reserved on the inserting plate for the prestressed steel strand to pass through. The prestressed steel strand runs through the entire connecting assembly and is anchored on the outer side of the inserting plate using the anchor. The inner plug-in and the connecting plate are only in contact and not welded. When the energy-absorbing metal part is stretched and deformed under force, the contact point between the inner plug-in and the connecting plate can be lifted, and the tension generated by the stretching of the prestressed steel strand cooperates with the deadweight of the upper module column to reset the swing reset node.
[0016] Furthermore, the column inner component comprises:
[0017] Inner ring plate 1 and inner ring plate 2 are welded to the inner side of the module column; the inner ring plate 2 is located below the inner ring plate 1, and a gap is left between the inner ring plate 1 and the inner ring plate 2; and
[0018] Two springs, each of which is connected to a spring fixing plate and a clamping block at both ends; the two spring fixing plates are respectively welded to the edges of the upper surface of the inner ring plate 2; the clamping block moves in the gap between the inner ring plate 1 and the inner ring plate 2, and the clamping block is used to limit the inner plug-in.
[0019] Furthermore, the connection component further includes:
[0020] Bolt 1 and Bolt 2;
[0021] The inner plug and the energy-dissipating metal piece are both provided with a third through hole for the passage of the first bolt; the horizontal connecting plate and the energy-dissipating metal piece are both provided with a fourth through hole for the passage of the second bolt;
[0022] The bolt 1 passes through the third through hole to connect the inner plug-in component with the energy-dissipating metal component;
[0023] The second bolt passes through the fourth through hole to connect the horizontal connecting plate and the energy-absorbing metal member.
[0024] Furthermore, the connection component further includes:
[0025] Two shear keys are respectively welded to the upper and lower ends of the horizontal connecting plate, and the upper module column and the lower module column are respectively sleeved on the two shear keys.
[0026] Furthermore, the inner plug-in is selected from at least one of H-shaped steel or hollow square steel tube.
[0027] Furthermore, the prestressed steel strands are replaced with prestressed steel rods or SMA rods or fiber reinforced materials.
[0028] Furthermore, the energy-absorbing metal part is selected from at least one of angle steel and T-shaped steel.
[0029] Furthermore, a friction plate is added between the energy-absorbing metal part and the inner plug-in component to realize a dual energy-absorbing mechanism of yield and friction.
[0030] In a second aspect, the present invention further provides a method for using the swing reset node of the modular steel structure according to the first aspect, comprising the following steps:
[0031] S1. In a factory, assemble the inner ring plate 1, the inner ring plate 2, the spring fixing plate, the spring, and the clamping block into an inner column assembly, and install the inner column assembly in a modular column including an upper modular column and a lower modular column; assemble the horizontal connecting plate, the shear key, the first bolt, the second bolt, the prestressed steel strand, the anchor, the energy-absorbing metal part, the inner plug-in, and the plug-in plate into a connection assembly; after assembly, transport the connection assembly and the modular column with the inner column assembly to the construction site;
[0032] S2. Hoist the lower module column and install the connecting assembly on its upper end. The plug plate at the lower end of the connecting assembly passes through the block in the lower module column and is locked, thereby completing the connection between the lower module column and the connecting assembly.
[0033] S3. Hoist the upper module column, align its lower end with the installed connection component, and then lower it. The plug plate at the upper end of the connection component passes through the block inside the upper module column and is locked, thereby completing the connection between the upper module column and the connection component.
[0034] Compared with the prior art, the present invention has the following beneficial effects:
[0035] (1) The present invention, through the arrangement of the column inner components and the connection components, can complete the assembly at the installation site by simply connecting the lower module column and the column inner components, the connection components and the upper module column and the column inner components. During the connection, only gravity is required to complete the connection between the upper module column and the lower module column. The connection is efficient and fast, saving time and effort. After the displacement is caused by the horizontal and vertical forces, the energy-consuming metal parts will be repeatedly stretched to consume energy, and the tension of the prestressed steel strands will achieve self-reset, thereby significantly reducing the residual deformation of the structure, solving the problem of the difficulty in applying the swing reset technology at the nodes of the modular steel structure, and at the same time achieving the effect of self-reset by using the prestressed steel strands in the modular structure without on-site anchoring, so that the modular steel structure can be restored to its function without repair or with only a small amount of repair, saving the cost of post-earthquake repair.
[0036] (2) By providing energy-absorbing metal parts and friction plates, the present invention can effectively consume energy when the structure is impacted by an earthquake, thereby improving the overall earthquake resistance of the building and ensuring the safety and stability of the building.
[0037] (3) The swing reset node of the present invention can be easily integrated with the existing modular steel structure system, which not only maintains the advantage of modular assembly efficiency but also enhances the seismic resistance of the structure. BRIEF DESCRIPTION OF THE DRAWINGS
[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0039] Figure 1 This is an overall schematic diagram of the swing reset node of the modular steel structure provided by the present invention after connection is completed;
[0040] Figure 2 A schematic diagram of a connection assembly of a swing reset node of a modular steel structure provided by the present invention;
[0041] Figure 3 An exploded schematic diagram of a swing reset node of a modular steel structure provided by the present invention;
[0042] Figure 4 This is a schematic diagram of the exploded components in the column provided by the present invention;
[0043] Figure 5 A schematic diagram of the connection method provided by the present invention;
[0044] Figure 6 for Figure 1Schematic diagram of the internal structure after removing the module column in area A;
[0045] Figure 7 for Figure 6 Schematic diagram of middle section B;
[0046] Figure 8 for Figure 6 Schematic diagram of the middle section C;
[0047] Figure 9 A schematic diagram of a swing reset node of a modular steel structure provided by the present invention after being stressed and before being reset;
[0048] Figure 10 A stress cloud diagram of a swing reset node of a modular steel structure provided by the present invention during a stress-bearing process;
[0049] Figure 11 This is the hysteresis curve of the swing reset node of the modular steel structure provided by the present invention under the finite element simulation of reciprocating loading.
[0050] Figure numerals: 1. Upper module column, 2. Lower module column, 3. Inner ring plate 1, 4. Inner ring plate 2, 5. Spring fixing plate, 6. Spring, 7. Horizontal connecting plate, 8. Shear key, 9. Bolt 1, 10. Bolt 2, 11. Prestressed steel strand, 12. Anchor, 13. Energy-absorbing metal parts, 14. Internal plug-in, 15. Block, 16. Insert plate. DETAILED DESCRIPTION
[0051] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.
[0052] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "upper", "lower", "inner", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.
[0053] In the description of the invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.
[0054] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.
[0055] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, percentages or ratios and other numerical values used in this specification and the appended claims are to be understood as being modified in all instances by the term "about." In addition, all ranges disclosed herein are inclusive and independently combinable. Example 1
[0056] This embodiment provides a self-locking and self-resetting node for modular steel structures, such as Figures 1-8 As shown, the modular steel structure has modular columns, which include an upper modular column 1 and a lower modular column 2. Figure 2 As shown, the swing reset node includes:
[0057] Two column components, mounted on the lower end of the upper module column 1 and the upper end of the lower module column 2 respectively; and
[0058] A connecting component is provided between the two column inner components and is used to connect the two column inner components;
[0059] Connectivity components, including:
[0060] Prestressed steel strand 11, with anchors 12 provided at both ends;
[0061] The horizontal connecting plate 7 has a first through hole reserved thereon for the prestressed steel strand 11 to pass through;
[0062] Two inner plug-ins 14 are respectively provided at the upper and lower ends of the horizontal connecting plate 7;
[0063] Two groups of energy-absorbing metal parts 13, two energy-absorbing metal parts 13 form a group, and each group of energy-absorbing metal parts 13 is symmetrically connected to the end side wall of each inner plug 14 close to the horizontal connecting plate 7;
[0064] Each inner plug 14 is connected to a plug plate 16 at one end away from the horizontal connecting plate 7. A second through hole is reserved on the plug plate 16 for the prestressed steel strand 11 to pass through. The prestressed steel strand 11 runs through the entire connection assembly and is anchored on the outside of the plug plate 16 using an anchor 12.
[0065] Specifically, if Figure 4 As shown, the column inner component includes: inner ring plate 1 3 and inner ring plate 2 4 welded on the inner side of the module column; inner ring plate 2 4 is located below inner ring plate 1 3, with a gap between inner ring plate 1 3 and inner ring plate 2 4; and two springs 6, each of which is connected to a spring fixing plate 5 and a clamping block 15 at both ends; the two spring fixing plates 5 are respectively welded on both sides of the edge of the upper surface of the inner ring plate 2 4; the clamping block 15 moves in the gap between inner ring plate 1 3 and inner ring plate 2 4, and the clamping block 15 is used to limit the inner plug-in 14.
[0066] like Figure 3 As shown, the connection assembly further includes: a first bolt 9 and a second bolt 10; a third through hole for the first bolt 9 to pass through is formed on the inner plug 14 and the energy-dissipating metal member 13; a fourth through hole for the second bolt 10 to pass through is formed on the horizontal connecting plate 7 and the energy-dissipating metal member 13;
[0067] Bolt 1 9 passes through the third through hole to connect the inner plug 14 to the energy-dissipating metal part 13;
[0068] The second bolt 10 passes through the fourth through hole to connect the horizontal connecting plate 7 to the energy-absorbing metal member 13;
[0069] like Figure 9 As shown, since the inner plug 14 and the horizontal connecting plate 7 are only in contact and not directly connected, when subjected to external force, the inner plug 14 will follow the upper module column 1 to rise relative to the horizontal connecting plate 7 to stretch the prestressed steel strand 11. The tension generated by the stretching of the prestressed steel strand 11 cooperates with the self-weight of the upper module column 1 as a restoring force to reset the swing reset node.
[0070] like Figure 2 As shown, the connection assembly further includes: two shear keys 8, which are respectively welded to the upper and lower ends of the horizontal connection plate 7, and the upper module column 1 and the lower module column 2 are respectively sleeved on the two shear keys 8.
[0071] Preferably, the inner plug 14 is selected from at least one of an H-shaped steel or a hollow square steel tube.
[0072] Preferably, the prestressed steel strands 11 are replaced with prestressed steel rods or SMA rods or fiber reinforced materials.
[0073] Preferably, the energy-absorbing metal member 13 is selected from at least one of angle steel and T-shaped steel.
[0074] Preferably, a friction plate is added between the energy-absorbing metal part 13 and the inner plug-in part 14 .
[0075] Figure 10 The stress cloud diagram of the swing reset node of the modular steel structure provided by the present invention during the stress process is as follows: Figure 10 As shown, the stress and deformation are mainly concentrated on the energy-consuming metal part 13 and the bolt 10, the stress on the module column is very small, and the energy-consuming metal part 13 can exert its energy-consuming capacity through deformation.
[0076] Figure 11 The hysteresis curve of the swing reset node of the modular steel structure provided by the present invention under the finite element simulation of reciprocating loading has a relatively full hysteresis loop, indicating that the energy dissipation effect is good, the residual displacement is very small, and the self-reset effect is good.
[0077] The present invention realizes the automatic reset function of the structure after being subjected to lateral force through the cooperation of the column components and the connection components, effectively reduces the residual deformation of the structure after the earthquake, and reduces the workload and cost of subsequent repairs. Compared with the traditional on-site anchoring method, the swing reset node of the present invention can be pre-assembled in the factory, avoiding the complex on-site anchoring process and is not restricted by the construction space. It is suitable for modular steel structure buildings under various site conditions, can simplify the construction process, and improve construction efficiency. Example 2
[0078] This embodiment provides a modular steel structure swing reset node and a method for using the same, specifically comprising the following steps:
[0079] S1. In the factory, assemble the inner ring plate 1 3, inner ring plate 2 4, spring fixing plate 5, spring 6, and clamping block 15 into an inner column assembly, and install the inner column assembly into the modular column including the upper modular column 1 and the lower modular column 2; assemble the horizontal connecting plate 7, shear key 8, bolt 1 9, bolt 2 10, prestressed steel strand 11, anchor 12, energy-absorbing metal part 13, inner plug 14, and insert plate 16 into a connection assembly; after assembly, transport the connection assembly and the modular column with the inner column assembly to the construction site;
[0080] S2. Hoist the lower module column 2 and install the connecting assembly on its upper end. The plug plate 16 at the lower end of the connecting assembly passes through the block 15 in the lower module column 2 and is locked, thereby completing the connection between the lower module column 2 and the connecting assembly.
[0081] S3. Hoist the upper module column 1, align its lower end with the installed connection component and then lower it. The plug plate 16 at the upper end of the connection component passes through the block 15 inside the upper module column 1 and is locked, thereby completing the connection between the upper module column 1 and the connection component.
[0082] Preferably, before connection, the two blocks 15 are pushed apart by a limit block, and when the plug-in plate 16 passes between the two blocks 15, the limit block is pushed out. After the plug-in plate 16 passes through the block 15, the block 15 pops out under the action of the spring 6 to lock the plug-in plate 16, thereby realizing the connection between the connecting component and the module column.
[0083] After the connection between the upper module column and the lower module column is completed according to the above steps, when the entire modular steel structure is subjected to an earthquake, the swing reset node can be swing reset under the action of the prestressed steel strand 11, thereby significantly reducing the residual deformation of the modular steel structure.
[0084] The present invention can complete the assembly on site by simply connecting the lower module column 2 and the components inside the column, the connecting components and the upper module column 1 and the components inside the column. During the connection process, only gravity is required to complete the connection between the upper module column and the lower module column. The connection is efficient and fast, saving time and effort. After being displaced by horizontal and vertical forces, the energy-consuming metal parts 13 are repeatedly stretched to consume energy, and self-reset is achieved through the tension of the prestressed steel strands 11, thereby significantly reducing the residual deformation of the structure, so that the modular steel structure can be restored to its usable function without repair or with only a small amount of repair, saving post-earthquake repair costs, and solving the problem of the difficulty in applying the swing reset technology at the nodes of the modular steel structure.
[0085] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.
Claims
1. A modular steel structure swing reset node, characterized in that: The modular steel structure has modular columns, the modular columns comprising an upper modular column (1) and a lower modular column (2), and the rocking reset node comprises: Two column inner components are respectively mounted on the lower end of the upper module column (1) and the upper end of the lower module column (2); and A connecting component is provided between the two in-column components and is used to connect the two in-column components; The connection component includes: Prestressed steel strand (11), with anchors (12) provided at both ends; A horizontal connecting plate (7) having a first through hole reserved thereon for the prestressed steel strand (11) to pass through; Two inner plug-ins (14) are respectively arranged at the upper and lower ends of the horizontal connecting plate (7); Two groups of energy-absorbing metal parts (13), two energy-absorbing metal parts (13) form a group, and each group of energy-absorbing metal parts (13) is symmetrically connected to the end side wall of each of the inner plug-in parts (14) close to the horizontal connecting plate (7); Each of the inner plug-ins (14) is connected to a plug-in plate (16) at one end away from the horizontal connecting plate (7). A second through hole is reserved on the plug-in plate (16) for the prestressed steel strand (11) to pass through. The prestressed steel strand (11) runs through the entire connecting assembly and is anchored on the outside of the plug-in plate (16) using the anchor (12).
2. The swing reset node of modular steel structure according to claim 1, characterized in that: The column inner component comprises: An inner ring plate 1 (3) and an inner ring plate 2 (4) are welded to the inner side of the module column; the inner ring plate 2 (4) is located below the inner ring plate 1 (3), and a gap is left between the inner ring plate 1 (3) and the inner ring plate 2 (4); and, Two springs (6), each of the two ends of the spring (6) is connected to a spring fixing plate (5) and a clamping block (15); the two spring fixing plates (5) are respectively welded to the edges of the upper surface of the inner ring plate (4); the clamping block (15) moves in the gap between the inner ring plate (3) and the inner ring plate (4), and the clamping block (15) is used to limit the inner plug-in (14).
3. The swing reset node of modular steel structure according to claim 2, characterized in that: The connection component further includes: Bolt one (9) and bolt two (10); The inner plug-in (14) and the energy-dissipating metal part (13) are both provided with a third through hole for the passage of the first bolt (9); the horizontal connecting plate (7) and the energy-dissipating metal part (13) are both provided with a fourth through hole for the passage of the second bolt (10); The bolt 1 (9) passes through the third through hole to connect the inner plug-in (14) to the energy-consuming metal part (13); The second bolt (10) passes through the fourth through hole to connect the horizontal connecting plate (7) to the energy-absorbing metal part (13).
4. The swing reset node of modular steel structure according to claim 3, characterized in that: The connection component further includes: Two shear keys (8) are respectively welded to the upper and lower ends of the horizontal connecting plate (7), and the upper module column (1) and the lower module column (2) are respectively sleeved on the two shear keys (8).
5. The swing reset node of modular steel structure according to claim 1, characterized in that: The inner plug-in (14) is selected from at least one of an H-shaped steel or a hollow square steel tube.
6. The swing reset node of modular steel structure according to claim 1, characterized in that: The prestressed steel strands (11) are replaced with prestressed steel rods or SMA rods or fiber-reinforced materials.
7. The swing reset node of modular steel structure according to claim 1, characterized in that: The energy-absorbing metal part (13) is selected from at least one of angle steel and T-shaped steel.
8. The swing reset node of modular steel structure according to claim 1, characterized in that: A friction plate is added between the energy-consuming metal part (13) and the inner plug-in part (14).
9. A method for using the swing reset node of the modular steel structure according to claim 4, characterized in that: The following steps are involved: S1. Assemble the inner ring plate 1 (3), the inner ring plate 2 (4), the spring fixing plate (5), the spring (6) and the clamping block (15) into the column inner assembly in the factory, and install the column inner assembly in the module column including the upper module column (1) and the lower module column (2); assemble the horizontal connecting plate (7), the shear key (8), the bolt 1 (9), the bolt 2 (10), the prestressed steel strand (11), the anchor (12), the energy-absorbing metal part (13), the inner plug-in (14) and the plug-in plate (16) into the connection assembly; after the assembly is completed, transport the connection assembly and the module column with the column inner assembly to the construction site; S2, hoisting the lower module column (2), and installing the connecting assembly at its upper end, wherein the plug plate (16) at the lower end of the connecting assembly passes through the block (15) in the lower module column (2) and is locked, thereby completing the connection between the lower module column (2) and the connecting assembly; S3, hoisting the upper module column (1), aligning its lower end with the installed connecting assembly and then lowering it, the plug plate (16) at the upper end of the connecting assembly passes through the clamping block (15) inside the upper module column (1) and is locked, thereby completing the connection between the upper module column (1) and the connecting assembly.
Citation Information
Patent Citations
In-column lifting controlled swing steel frame based on piston device
CN114232800A
In-column lifting controlled swing steel frame based on piston device
CN216640915U