Fabricated concrete temporary road hidden hanging ring manufacturing equipment and method
The concealed lifting ring structure solves the problem of debris accumulation in the lifting rings, ensuring efficient lifting and construction progress, and improving the utilization efficiency of temporary roads.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA HUAYE GROUP
- Filing Date
- 2026-03-10
- Publication Date
- 2026-05-08
AI Technical Summary
The lifting ring structure of traditional prefabricated concrete temporary roads is prone to accumulating mud, gravel and debris, resulting in low lifting efficiency, increased labor input and affecting construction progress.
A concealed lifting ring structure was designed, including a rectangular groove, a cover plate mechanism, a reset mechanism, and a positioning mechanism. The cover plate mechanism seals the rectangular groove, and the reset mechanism automatically resets it to prevent debris from accumulating. During hoisting, the cover plate can be manually pulled open to expose the hook, and it will automatically seal after hoisting is completed.
This reduced the need for manual debris removal, improved hoisting efficiency, and ensured the turnover of temporary roads and the progress of construction.
Smart Images
Figure CN121990454A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of concrete temporary road technology, and more particularly to equipment and method for manufacturing concealed hanging rings for prefabricated concrete temporary roads. Background Technology
[0002] Traditionally, during earthwork excavation, temporary roads at construction sites often need to be rerouted multiple times depending on the construction progress and site conditions. The relocation of temporary roads typically involves loading and unloading operations using excavators and transport machinery. Currently, the lifting rings of conventional prefabricated concrete temporary roads are mostly exposed structures, without sealing covers at the ring holes. This allows mud, gravel, and debris to accumulate during use. Each time a prefabricated concrete road slab is lifted, debris in the holes obstructs the hook operation, requiring manual cleaning before lifting can proceed. This not only increases labor input but also reduces lifting efficiency, impacting the turnover of temporary roads and the construction progress. Summary of the Invention
[0003] The purpose of this invention is to address the problems existing in the background art by proposing a prefabricated concrete temporary road concealed hanging ring manufacturing equipment and method.
[0004] On the one hand, this application provides a prefabricated concrete temporary road concealed hanging ring manufacturing equipment, including a concrete slab, and further including: a plurality of rectangular grooves formed on the concrete slab, the top of the rectangular grooves being rotatably connected to a cover plate mechanism, the interior of the rectangular grooves being provided with a reset mechanism that causes a steel cover plate to automatically rotate and close the rectangular grooves, and the top of the rectangular grooves being provided with a positioning mechanism that restricts the cover plate mechanism from blocking the top opening of the rectangular grooves; and a hanging ring mechanism disposed in the rectangular grooves, the hanging ring mechanism being used to be covered by the cover plate mechanism.
[0005] Optionally, the cover plate mechanism includes a steel cover plate that blocks the top opening of the rectangular groove, the top of the rectangular groove has a rotating groove, a pair of steel rings are embedded inside the rotating groove, and a pair of rotating shafts inserted into the steel rings are fixedly connected to one side wall of the steel cover plate.
[0006] Optionally, the positioning mechanism includes multiple slots formed on the concrete slab that communicate with the rectangular groove, the slots being used to engage the end of the steel cover plate away from the rotation axis.
[0007] Optionally, the slot has an arc-shaped groove inside, and the steel cover plate has a notch aligned with the arc-shaped groove at the end away from the rotating shaft.
[0008] Optionally, the reset mechanism includes a pair of reset springs disposed inside the rectangular groove, a pair of first support rings fixedly connected to the lower surface of the steel cover plate, a rectangular PVC sleeve fixedly connected to the inside of the rectangular groove, a second support ring corresponding to the first support rings fixedly connected to the inner wall of the rectangular PVC sleeve, and hooks fixedly connected to the first and second support rings at both ends of the reset springs.
[0009] Optionally, the lifting ring mechanism includes multiple reinforcing bars disposed within the concrete slab, and each of the rectangular grooves is provided with a hook, which is welded to the corresponding reinforcing bar.
[0010] Optionally, the inner bottom wall of the rectangular groove is provided with multiple through holes, and the steel cover plate is provided with switch arrows.
[0011] Optionally, multiple pairs of reinforcing grooves are provided on the concrete slab, one pair of the reinforcing grooves is provided with a first reinforcing angle steel, and the other pair of the reinforcing grooves is provided with a second reinforcing angle steel. The connecting ends of the first reinforcing angle steel and the second reinforcing angle steel are welded together.
[0012] On the other hand, this application provides a method for manufacturing concealed lifting rings for prefabricated concrete temporary roads, applied to the prefabricated concrete temporary road concealed lifting ring manufacturing equipment as described above, including the following steps: S1. First, the steel cover plate is inserted into the slot under the elastic force of the reset mechanism and seals the top opening of the rectangular slot. The switch arrow remains clearly visible, which not only prevents soil, sand and gravel from entering and accumulating in the rectangular slot, but also visually indicates the opening direction of the steel cover plate.
[0013] S2. Then, the operator inserts their fingers into the slot through the arc-shaped groove and pulls the end of the steel cover plate away from the rotating shaft outward, causing the steel cover plate to rotate around the rotating shaft in the rotating groove. During the rotation, the return spring is stretched and elastically deformed until the steel cover plate is disengaged from the slot, exposing the hook in the rectangular groove, thus preparing for subsequent hoisting operations.
[0014] S3. Next, connect the external lifting hook to the exposed hook inside the rectangular groove, start the lifting equipment, and smoothly complete the lifting operation of the concrete slab to ensure the smooth progress of the lifting operation.
[0015] S4. After hoisting is completed, release the tension on the steel cover plate. Use the elastic restoring force of the return spring to drive the steel cover plate to rotate in the opposite direction until the end of the steel cover plate away from the rotation axis re-enters the slot and the arc-shaped slot aligns with the groove. This allows the steel cover plate to seal the rectangular slot again, hide the hook, and restore the equipment to its protective state.
[0016] Compared with the prior art, this application includes at least one of the following beneficial technical effects: This invention utilizes the cooperation of a cover plate mechanism, a reset mechanism, a positioning mechanism, and a lifting ring mechanism. Normally, the steel cover plate is locked into the rectangular groove by the reset mechanism to prevent the accumulation of soil and gravel. During hoisting, the steel cover plate is pulled open by the arc-shaped groove, exposing the hook to complete the hoisting. After hoisting, the reset spring drives the steel cover plate to automatically lock into the groove and reset. No manual cleaning of debris is required, reducing labor input, improving hoisting efficiency, and ensuring the turnover of temporary roads and the progress of construction. Attached Figure Description
[0017] Figure 1 A structural schematic diagram of a concealed lifting ring fabrication device for prefabricated concrete temporary roads; Figure 2 for Figure 1 A schematic diagram of the cross-sectional structure; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 for Figure 2 A schematic diagram of the structure viewed from below; Figure 5 for Figure 4 Enlarged view of point B in the middle; Figure 6 for Figure 4 A schematic diagram of the split structure; Figure 7 for Figure 6 Enlarged diagram of point C in the middle.
[0018] Reference numerals: 1. Concrete slab; 11. Rectangular groove; 12. Rectangular PVC sleeve; 13. Rotating groove; 14. Slot; 15. Arc groove; 16. Steel ring; 17. Reinforcing steel bar; 18. Hook; 19. Perforation; 101. Reinforcing groove; 102. First reinforcing angle steel; 103. Second reinforcing angle steel; 2. Steel cover plate; 21. Rotating shaft; 22. Slot; 23. Switch arrow; 3. Return spring; 31. First support ring; 32. Second support ring; 33. Hook. Detailed Implementation
[0019] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0020] The components of the embodiments of the invention described and shown in the accompanying drawings can typically be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.
[0021] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0023] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Example
[0025] like Figures 1 to 7As shown, the prefabricated concrete temporary road concealed lifting ring manufacturing equipment proposed in this invention includes a concrete slab 1, which has dimensions of 3000mm in length, 2000mm in width, and 250mm in thickness. Multiple rectangular grooves 11 are formed on the concrete slab 1, providing space for the lifting ring mechanism and reset mechanism, and are concealed and closed by a steel cover plate 2 to achieve the concealment and storage of the lifting hook 18. The depth of the rectangular grooves 11 is 170mm. Multiple perforations 19 are formed on the inner bottom wall of each rectangular groove 11 to prevent water accumulation and corrosion of the internal mechanisms, thus affecting the use of the equipment. The steel cover plate 2 has a switch arrow 23, which is a functional indicator on the steel cover plate 2 in the prefabricated concrete temporary road concealed lifting ring equipment. Its core function is to intuitively and clearly indicate the opening direction of the steel cover plate.
[0026] Among them, such as Figure 1 , Figure 2 , Figure 3 , Figure 5 , Figure 6 and Figure 7 As shown, a cover plate mechanism is rotatably connected to the top of the rectangular groove 11. The cover plate mechanism includes a steel cover plate 2 that blocks the top opening of the rectangular groove 11. The steel cover plate 2 seals the top opening of the rectangular groove 11, concealing the hook 18 and preventing debris such as mud and sand from entering the rectangular groove 11. A rotating groove 13 is provided at the top of the rectangular groove 11, providing space for the rotation of the steel cover plate 2 and ensuring flexible rotation of the cover plate mechanism. A pair of steel rings 16 are embedded inside the rotating groove 13. The steel rings 16 cooperate with the rotating shaft 21 of the steel cover plate 2 to realize the rotatable connection of the steel cover plate 2 and provide a pivot support for the opening and closing of the cover plate. A pair of rotating shafts 21 inserted into the steel rings 16 are fixedly connected to one side wall of the steel cover plate 2. The rotating shafts 21 are inserted into the steel rings 16 and cooperate with the steel rings 16 to realize the rotation of the steel cover plate 2, providing a rotational basis for the opening and closing of the cover plate.
[0027] Secondly, such as Figure 5 and Figure 7 As shown, the top of the rectangular groove 11 is also provided with a positioning mechanism to restrict the cover plate mechanism from blocking the top opening of the rectangular groove 11. The positioning mechanism includes multiple slots 14 formed on the concrete slab 1 that communicate with the rectangular groove 11. The slots 14 allow the end of the steel cover plate 2 away from the rotation shaft 21 to be engaged, thereby achieving the positioning and sealing of the rectangular groove 11 by the steel cover plate 2. The slots 14 are used for the end of the steel cover plate 2 away from the rotation shaft 21 to be engaged. The inside of the slots 14 is provided with an arc-shaped groove 15. The arc-shaped groove 15 facilitates the operator to insert their fingers into the slot 22, providing operating space for pulling open the steel cover plate 2. The end of the steel cover plate 2 away from the rotation shaft 21 is provided with a slot 22 aligned with the arc-shaped groove 15. The slot 22 allows the operator to hook and pull with their fingers, providing a point of force for pulling open the steel cover plate 2.
[0028] In addition, such as Figure 3 , Figure 5 and Figure 7 As shown, the rectangular groove 11 is equipped with a reset mechanism inside, which automatically rotates the steel cover plate 2 to close the rectangular groove 11. The reset mechanism includes a pair of reset springs 3 disposed inside the rectangular groove 11. The two ends of the reset springs 3 are connected to a first support ring 31 and a second support ring 32 via hooks 33. The elastic force drives the steel cover plate 2 to automatically reset and seal the rectangular groove 11. A pair of first support rings 31 are fixedly connected to the lower surface of the steel cover plate 2. The first support rings 31 are connected to one of the hooks 33 of the reset springs 3, providing a connection fulcrum for the reset springs 3 to the steel cover plate 2 and transmitting elastic tension. A rectangular PVC sleeve 12 is fixedly connected inside the rectangular groove 11. A second support ring 32 corresponding to the first support ring 31 is fixedly connected to the inner wall of the rectangular PVC sleeve 12. The second support ring 32 is connected to the other hook 33 of the reset spring 3, providing a fixed fulcrum for the reset spring 3 and cooperating with the first support ring 31 to stretch the reset spring 3. Both ends of the return spring 3 are fixedly connected to hooks 33 that are hung on the first support ring 31 and the second support ring 32. The hooks 33 are used to realize the detachable connection between the return spring 3 and the two support rings and to transmit elastic force.
[0029] It is worth noting that, such as Figure 3 , Figure 5 and Figure 7 As shown, a lifting ring mechanism is provided inside the rectangular groove 11. This mechanism is concealed by the cover plate mechanism. The lifting ring mechanism includes multiple reinforcing steel bars 17 embedded within the concrete slab 1. These reinforcing steel bars 17 are welded and fixed to hooks 18, enhancing the connection strength of the hooks 18 and ensuring structural stability during lifting operations. Before pouring, the reinforcing steel bars 17 undergo rust removal, degreasing, and drying treatment. A mature steel reinforcement rust inhibitor is added to the concrete, ensuring both concrete density and sufficient protective layer thickness. An external rust inhibitor is applied to the exposed reinforcing steel bars 17 within the rectangular groove 11 to form a sealed protective film, achieving long-term rust prevention through multiple layers of protection. Each rectangular groove 11 is equipped with a hook 18, which connects to external lifting hooks to enable the lifting of the concrete slab 1. This hook is the core lifting component of the lifting ring mechanism. The hooks 18 are HPB300 grade Φ18 steel bars. The hooks 18 are welded to the corresponding reinforcing steel bars 17.
[0030] Furthermore, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 6As shown, multiple pairs of reinforcing grooves 101 are provided on the concrete slab 1. These grooves provide space for the first reinforcing angle steel 102 and the second reinforcing angle steel 103, enabling their embedded installation. One pair of grooves 101 houses the first reinforcing angle steel 102, which is welded to the second reinforcing angle steel 103 to enhance the overall structural strength of the concrete slab 1. The other pair of grooves 101 houses the second reinforcing angle steel 103, which is welded to the first reinforcing angle steel 102 to form a reinforced structure, enhancing the stability of the concrete slab 1 during hoisting and use. The connection between the first reinforcing angle steel 102 and the second reinforcing angle steel 103 is achieved by welding.
[0031] This application provides a method for fabricating concealed hanging rings for prefabricated concrete temporary roads, such as... Figure 1 - Figure 7 As shown, it includes the following steps: S1. First, the steel cover plate 2 is inserted into the slot 14 under the elastic force of the reset mechanism and seals the top opening of the rectangular slot 11. The switch arrow 23 remains clearly visible, which not only prevents soil, sand and gravel from entering and accumulating in the rectangular slot 11, but also visually indicates the opening direction of the steel cover plate 2.
[0032] S2. Then, the operator inserts his finger into the slot 22 through the arc groove 15 and pulls the end of the steel cover plate 2 away from the rotating shaft 21, so that the steel cover plate 2 rotates around the rotating shaft 21 in the rotating groove 13. During the rotation, the return spring 3 is stretched and deformed elastically until the steel cover plate 2 is disengaged from the slot 14, so that the hook 18 in the rectangular groove 11 is exposed, which is ready for subsequent hoisting operations.
[0033] S3. Next, connect the external lifting hook to the exposed hook 18 inside the rectangular groove 11, start the lifting equipment, and smoothly complete the lifting operation of the concrete slab 1 to ensure the smooth progress of the lifting operation.
[0034] S4. After hoisting is completed, release the tension on the steel cover plate 2. Use the elastic restoring force of the return spring 3 to drive the steel cover plate 2 to rotate in the opposite direction until the end of the steel cover plate 2 away from the rotating shaft 21 is re-engaged into the slot 14, and the arc groove 15 is aligned with the slot 22, so that the steel cover plate 2 seals the rectangular slot 11 again, hides the hook 18, and restores the protective state of the equipment.
[0035] In this embodiment, when using the prefabricated concrete temporary road hidden lifting ring manufacturing equipment, during daily use, the steel cover plate 2 is inserted into the slot 14 by the elastic force of the reset mechanism, sealing the top opening of the rectangular slot 11 and preventing soil, sand and gravel and other debris from accumulating in the rectangular slot 11. At the same time, the switch arrow 23 can intuitively indicate the opening direction of the steel cover plate 2. When it is necessary to lift the concrete slab 1, the operator can insert his / her fingers into the slot 22 through the arc-shaped slot 15 and pull the end of the steel cover plate 2 away from the rotating shaft 21 outward, so that the steel cover plate 2 rotates around the rotating shaft 21 in the rotating slot 13. During the rotation, the steel cover plate 2 will drive the first support ring 31 to stretch the reset spring 3, so that the reset spring 3 will generate elastic deformation on the second support ring 32 through the hook 33. After the steel cover plate 2 is removed from the slot 14, the lifting hook 18 in the rectangular slot 11 will be exposed. At this time, the lifting hook can be connected to the lifting hook 18 to complete the lifting operation of the concrete slab 1.
[0036] After hoisting is completed, the tension on the steel cover plate 2 is released. The elastic restoring force of the return spring 3 will pull the first support ring 31 through the hook 33, causing the steel cover plate 2 to rotate in the opposite direction around the rotating shaft 21 until the end of the steel cover plate 2 away from the rotating shaft 21 is re-engaged into the slot 14, the arc groove 15 is aligned with the slot 22, and the steel cover plate 2 seals the rectangular groove 11 again, completing the reset. The reinforcing steel bar 17 in the concrete slab 1 is welded and fixed to the hook 18 to improve the connection strength of the hook 18. The perforation 19 can ensure that water does not accumulate in the sealed rectangular groove 11, and the first reinforcing angle steel 102 and the second reinforcing angle steel 103 in the reinforcing groove 101 are welded together to further improve the overall structural strength of the concrete slab 1 and ensure stability during hoisting and use.
[0037] The preferred embodiments of the present invention described above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A prefabricated concrete temporary road concealed lifting ring manufacturing equipment, comprising a concrete slab (1), characterized in that, Also includes: Multiple rectangular slots (11) are formed on the concrete slab (1). The top of the rectangular slots (11) is rotatably connected to a cover plate mechanism. The interior of the rectangular slots (11) is provided with a reset mechanism that allows the steel cover plate (2) to automatically rotate and close the rectangular slots (11). The top of the rectangular slots (11) is also provided with a positioning mechanism that restricts the cover plate mechanism from blocking the top opening of the rectangular slots (11). A lifting ring mechanism is provided in the rectangular groove (11), and the lifting ring mechanism is used to be covered by the cover plate mechanism.
2. The prefabricated concrete temporary road concealed lifting ring manufacturing equipment according to claim 1, characterized in that, The cover plate mechanism includes a steel cover plate (2) that blocks the top opening of the rectangular groove (11). A rotating groove (13) is provided at the top of the rectangular groove (11). A pair of steel rings (16) are embedded inside the rotating groove (13). A pair of rotating shafts (21) inserted into the steel rings (16) are fixedly connected to one side wall of the steel cover plate (2).
3. The prefabricated concrete temporary road concealed lifting ring manufacturing equipment according to claim 1, characterized in that, The positioning mechanism includes multiple slots (14) formed on the concrete slab (1) and communicating with the rectangular groove (11), the slots (14) being used to engage one end of the steel cover plate (2) away from the rotating shaft (21).
4. The prefabricated concrete temporary road concealed lifting ring manufacturing equipment according to claim 3, characterized in that, The slot (14) has an arc-shaped groove (15) inside, and the steel cover plate (2) has a notch (22) aligned with the arc-shaped groove (15) at one end away from the rotating shaft (21).
5. The prefabricated concrete temporary road concealed lifting ring manufacturing equipment according to claim 1, characterized in that, The reset mechanism includes a pair of reset springs (3) disposed inside the rectangular groove (11), a pair of first support rings (31) are fixedly connected to the lower surface of the steel cover plate (2), a rectangular PVC sleeve (12) is fixedly connected inside the rectangular groove (11), a second support ring (32) corresponding to the first support ring (31) is fixedly connected to the inner wall of the rectangular PVC sleeve (12), and hooks (33) are fixedly connected to both ends of the reset spring (3) and hung on the first support ring (31) and the second support ring (32).
6. The prefabricated concrete temporary road concealed lifting ring manufacturing equipment according to claim 1, characterized in that, The lifting ring mechanism includes multiple reinforcing steel bars (17) set in the concrete slab (1), and each rectangular groove (11) is provided with a hook (18), which is welded to the corresponding reinforcing steel bar (17).
7. The prefabricated concrete temporary road concealed lifting ring manufacturing equipment according to claim 1, characterized in that, The inner bottom wall of the rectangular groove (11) is provided with multiple through holes (19), and the steel cover plate (2) is provided with switch arrows (23).
8. The prefabricated concrete temporary road concealed lifting ring manufacturing equipment according to claim 1, characterized in that, The concrete slab (1) has multiple pairs of reinforcing grooves (101), one pair of the reinforcing grooves (101) is provided with a first reinforcing angle steel (102), and the other pair of the reinforcing grooves (101) is provided with a second reinforcing angle steel (103). The connecting ends of the first reinforcing angle steel (102) and the second reinforcing angle steel (103) are welded together.
9. A method for manufacturing concealed lifting rings for prefabricated concrete temporary roads, applied to the prefabricated concrete temporary road concealed lifting ring manufacturing equipment as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. First, the steel cover plate (2) is inserted into the slot (14) under the elastic force of the reset mechanism and the top opening of the rectangular slot (11) is sealed. The switch arrow (23) remains clearly visible, which not only prevents soil, sand and gravel from entering the rectangular slot (11) and accumulating, but also visually indicates the opening direction of the steel cover plate (2). S2. Then the operator inserts his finger through the arc groove (15) into the slot (22) and pulls the steel cover plate (2) away from the rotating shaft (21) so that the steel cover plate (2) rotates around the rotating shaft (21) in the rotating groove (13). During the rotation, the return spring (3) is stretched and deformed elastically until the steel cover plate (2) is disengaged from the slot 14, so that the hook (18) in the rectangular groove (11) is exposed, which is ready for subsequent hoisting operations. S3. Next, connect the external lifting hook to the exposed hook (18) in the rectangular groove (11), start the lifting equipment, and smoothly complete the lifting operation of the concrete slab (1) to ensure the smooth progress of the lifting operation. S4. After hoisting is completed, release the tension on the steel cover plate (2), and use the elastic restoring force of the return spring (3) to drive the steel cover plate (2) to rotate in the opposite direction until the end of the steel cover plate (2) away from the rotating shaft (21) is re-engaged into the slot (14), and the arc groove (15) is aligned with the slot (22), so that the steel cover plate (2) seals the rectangular slot (11) again, hides the hook (18), and restores the protective state of the equipment.