阅读说明：本技术 预紧结构及人孔检修门 (Pre-tightening structure and manhole access door ) 是由 王雷 周冠东 段银龙 徐东进 刘琴 朱智新 李俊诺 王子豪 谭卜豪 郭森 曾冠锋 于 2021-07-26 设计创作，主要内容包括：本发明公开一种预紧结构及人孔检修门,预紧结构包括锁定件、开合件和弹性件。开合件具有与锁定件配合的锁定状态和脱离锁定件的开启状态；开合件能够通过弹性件弹性作用于锁定件；当开合件处于开启状态时,弹性件处于自然状态；开合件处于锁定状态时,开合件通过驱使弹性件变形且通过弹性件产生的恢复力以锁紧于锁定件。开合件与弹性件配合,在锁紧状态时实现自锁,解锁时需要给予开启件一大于恢复力的外力,预紧结构锁紧稳定性强,结构简单,锁紧效果好。人孔检修门包括底板、检修门体和预紧结构。通过预紧结构使得检修门能够锁紧于底板上,以盖合人孔,便于保证检修门与桥梁底板的贴合稳定性,避免检修门与桥梁底板发生相对运动。(The invention discloses a pre-tightening structure and a manhole access door. The opening and closing piece is provided with a locking state matched with the locking piece and an opening state separated from the locking piece; the opening and closing piece can elastically act on the locking piece through the elastic piece; when the opening and closing piece is in an opening state, the elastic piece is in a natural state; when the opening and closing piece is in a locking state, the opening and closing piece is locked on the locking piece by driving the elastic piece to deform and the restoring force generated by the elastic piece. The opening and closing piece is matched with the elastic piece, self-locking is achieved in the locking state, external force larger than restoring force is required to be given to the opening piece during unlocking, and the pre-tightening structure is strong in locking stability, simple in structure and good in locking effect. The manhole access door comprises a bottom plate, an access door body and a pre-tightening structure. Make the access door can lock on the bottom plate through the pretension structure to the manhole closes in the lid, be convenient for guarantee the laminating stability of access door and bridge bottom plate, avoid access door and bridge bottom plate to take place relative motion.)

1. The utility model provides a pretension structure for being connected of bridge access door and bottom plate, its characterized in that includes:

a locking member;

an opening member having a locked state engaged with the locking member and an opened state disengaged from the locking member; and

the elastic piece can enable the opening and closing piece to act on the locking piece through elasticity of the elastic piece; when the opening and closing piece is in an opening state, the elastic piece is in a natural state; when the opening and closing piece is in a locking state, the opening and closing piece is locked on the locking piece by driving the elastic piece to deform and through the restoring force generated by the elastic piece.

2. The pretensioning structure according to claim 1, further comprising a limiting ring fixedly connected with the bottom plate, wherein one end of the elastic member is fixedly connected with the limiting ring, one end of the opening and closing member penetrates through the limiting ring and is connected with the other end of the elastic member, and the opening and closing member moves relative to the limiting ring to drive the elastic member to switch between a deformed state and a natural state.

3. The pretensioning structure according to claim 2, wherein the locking member is provided with a guide slope for guiding engagement with the opening member, wherein the end of the guide slope located at the smaller thickness of the locking member is a small end, the end of the guide slope located at the larger thickness of the locking member is a large end, and the opening member is switched between the open state and the locked state by moving along the small end to the large end; when the opening and closing member is in an opening state, the opening member is positioned at the small end, and when the opening and closing member is in a locking state, the opening member is positioned at the large end.

4. The pretensioning structure of claim 3, wherein the large end is provided with a locking groove, and the opening element is in locking engagement with the locking groove when the opening element is in the locked state.

5. The pretensioning structure according to claim 4, wherein the opening and closing member is a T-shaped rotating rod, the opening and closing member comprises a top rod and a support rod, one end of the support rod is connected to the middle part of the top rod, the other end of the support rod penetrates through the limiting ring and is connected with the elastic member, and the top rod is rotatably connected to the locking member, so that the opening and closing member can be arranged on the locking member in an opening and closing manner.

6. The pretensioning structure according to claim 5, further comprising a fixing member, wherein the support rod sequentially penetrates through the limiting ring, the elastic member and the fixing member and is fixedly connected with the fixing member, the opening and closing member is connected to the elastic member through the fixing member, and the support rod is in clearance fit with the limiting ring and the elastic member respectively;

when the ejector rod rotates to the locking groove, the fixing piece is driven to move towards the direction close to the elastic piece, and the elastic piece is stressed and compressed and transmits restoring force to the fixing piece, so that the ejector rod is stressed and locked in the locking groove;

when the ejector rod is separated from the locking groove, the fixing piece is moved in the direction away from the elastic piece by the restoring force, so that the opening piece is separated from the locking piece.

7. A manhole access door, comprising the pretensioning structure according to any one of claims 1 to 6, and further comprising a bottom plate and an access door body, wherein a manhole is arranged on the bottom plate, the access door body is covered on the manhole, the locking piece is connected to the access door body, and the access door is connected to the bottom plate through the pretensioning structure in an openable and closable manner.

8. The manhole access door of claim 7, further comprising a reinforcing pad, wherein the reinforcing pad is provided with a through hole with a diameter larger than that of the manhole, the reinforcing pad is covered on the bottom plate, the manhole is located in the through hole, and the access door body is fixedly connected to the bottom plate through the reinforcing pad.

9. The manhole access door of claim 8, further comprising a rotating assembly, wherein the access door body is rotatably connected to the reinforcing liner plate through the rotating assembly.

10. The manhole access door of claim 9, further comprising a limit stop for limiting a range of rotation of the rotating assembly.

Technical Field

The invention relates to the technical field of steel structure bridges, in particular to a pre-tightening structure and a manhole access door.

Background

In the steel structure bridge, in order to satisfy the requirement that on-the-spot installer carries out the incasement construction and the later stage is carried out maintenance and maintenance to the steel box girder, can set up the inspection manhole at steel box bridge bottom plate usually. But along with the increase of people's trip demand, the bridge removes the load and increases day by day, the bridge takes place the vibration easily under great removal load effect, traditional access door mainly leans on dead weight and sealing rubber strip to carry out the laminating with the manhole, when the bridge takes place to vibrate from top to bottom, relative motion takes place easily with the steel box girder for access door to make access door probably break away from with sealing rubber strip, collide with steel box girder bottom plate even, send great abnormal sound, influence the travelling comfort.

Disclosure of Invention

Based on this, it is necessary to provide a pretension structure and manhole access door to in the laminating stability of assurance access door and bridge bottom plate, avoid access door and bridge bottom plate to take place relative motion.

The specific technical scheme is as follows:

in one aspect, the present application relates to a pretensioning structure comprising a locking member, an opening member and a resilient member. The opening piece is provided with a locking state matched with the locking piece and an opening state separated from the locking piece; the opening and closing piece can act on the locking piece through the elasticity of the elastic piece; when the opening and closing piece is in an opening state, the elastic piece is in a natural state; when the opening and closing piece is in a locking state, the opening and closing piece is locked on the locking piece by driving the elastic piece to deform and through the restoring force generated by the elastic piece.

When the pre-tightening structure is used, the opening and closing piece is matched with the locking piece, so that the opening and closing piece can be switched between a locking state and an opening state. When this pretension structure needs to be locked, this opening and shutting piece of drive to the locking state with locking piece complex, this opening and shutting piece is through ordering about this elastic component deformation this moment for this elastic component is in the stress state, can transmit restoring force to opening and shutting piece, is favorable to opening and shutting piece and locking piece locking, forms the auto-lock. When the locking structure needs to be opened, an external force greater than the restoring force is applied to the opening and closing piece to drive the opening and closing piece to be separated from the locking piece to be in an opening state, and the elastic piece elastically restores to be in a natural state. Should open and shut the piece and this elastic component cooperation, realize the auto-lock when locking state, need give this opening one during the unblock and be greater than the external force of the restoring force of elastic component transmission, this pretension structure locking stability is strong, simple structure, and locking effect is good.

The technical solution is further explained below:

in one embodiment, the pre-tightening structure further comprises a limiting ring fixedly connected with the bottom plate, one end of the elastic element is fixedly connected with the limiting ring, one end of the opening and closing element penetrates through the limiting ring and is connected with the other end of the elastic element, and the opening and closing element moves relative to the limiting ring to drive the elastic element to switch between a deformation state and a natural state. This elastic component sets up between this spacing ring and opening and shutting spare for when this opening and shutting spare switches between lock-out state and open mode, this opening and shutting spare produces relative motion with this spacing ring, thereby orders about this elastic component and switches between deformation state and natural state, and simple structure is reasonable, and it is convenient to assemble.

In one embodiment, the locking piece is provided with a guide inclined plane used for being in guide fit with the opening piece, one end of the guide inclined plane, positioned at the smaller thickness of the locking piece, is a small end, one end of the guide inclined plane, positioned at the larger thickness of the locking piece, is a large end, and the opening piece is switched between an opening state and a locking state by moving along the small end to the large end; when the opening and closing member is in an opening state, the opening member is positioned at the small end, and when the opening and closing member is in a locking state, the opening member is positioned at the large end. This opening and shutting piece is at direction inclined plane slip in-process, and the flexible length of elastic component can change in step, and when opening the piece and being located during the tip, the elastic component is in natural state, slides when opening the piece extremely during the tip, this elastic component stretches out and draws back along with the removal of opening and shutting piece to produce elastic restoring force, when this opening and shutting piece and locking piece cooperation locking, this elastic component transmission restoring force is in order to form the auto-lock to opening and shutting piece.

In one embodiment, the large end is provided with a locking groove, and the opening part is in locking fit with the locking groove when in a locking state. The locking groove is arranged to enable the opening and closing piece to be embedded into the locking groove when the opening and closing piece is in a locking state, when the pre-tightening structure is unlocked, an external force is required to be applied to the opening and closing piece to enable the opening and closing piece to be separated from the highest height of the locking groove, the self-locking stability of the opening and closing piece when the opening and closing piece is in the locking state is improved, and the opening and closing piece is prevented from being separated from the locking piece due to vibration.

In one of them embodiment, the piece of opening and shutting is the T type bull stick, the piece of opening and shutting includes ejector pin and bracing piece, the one end of bracing piece is connected in the middle part of ejector pin, the other end of bracing piece wear to locate the spacing ring and with the elastic component is connected, the ejector pin rotate connect in the locking piece, so that the piece of opening and shutting can set up in the locking piece with opening and shutting. The opening and closing piece can drive the ejector rod to rotate through the rotating supporting rod, and is matched with the locking piece through the guide inclined plane, so that the structure is simple and reasonable.

In one embodiment, the pre-tightening structure further comprises a fixing part, the supporting rod sequentially penetrates through the limiting ring, the elastic part and the fixing part and is fixedly connected with the fixing part, the opening and closing part is connected to the elastic part through the fixing part, and the supporting rod is in clearance fit with the limiting ring and the elastic part respectively;

when the ejector rod rotates to the locking groove, the fixing piece is driven to move towards the direction close to the elastic piece, and the elastic piece is stressed and compressed and transmits restoring force to the fixing piece, so that the ejector rod is stressed and locked in the locking groove;

when the ejector rod is separated from the locking groove, the fixing piece is moved in the direction away from the elastic piece by the restoring force, so that the opening piece is separated from the locking piece.

The fixing piece is arranged to facilitate elastic connection of the elastic piece and the opening and closing piece, the elastic piece is arranged between the limiting ring and the fixing piece, when the opening and closing piece is located in a locking state, the fixing piece moves towards the direction of the elastic piece to compress the elastic piece, so that the fixing piece is subjected to restoring force transmitted by the elastic piece, and the opening and closing piece can be stably self-locked in the locking groove under stress.

On the other hand, this application still provides a manhole access door, including the pretension structure in above-mentioned arbitrary embodiment, still include bottom plate and the access door body, be equipped with the manhole on the bottom plate, the access door body lid is located the manhole, the locking piece connect in the access door body, the access door passes through the pretension structure can open and shut connect in the bottom plate.

This manhole access door makes this access door can lock on the bottom plate through pretension structure to the laminating stability of assurance access door and bridge bottom plate is convenient for close this manhole, avoids access door and bridge bottom plate to take place relative motion.

In one embodiment, the manhole access door further comprises a reinforcing base plate, the reinforcing base plate is provided with a through hole with the aperture larger than that of the manhole, the reinforcing base plate is covered on the bottom plate, the manhole is located in the through hole, and the access door body is fixedly connected to the bottom plate through the reinforcing base plate. The reinforcing base plate is arranged to play a role in reinforcing a manhole, the pre-tightening structure and the access door are convenient to install, and the reinforcing base plate, the pre-tightening structure and the access door can be integrally pre-installed, so that the field construction efficiency is improved.

In one embodiment, the manhole access door further comprises a rotating assembly, and the access door body is rotatably connected to the reinforcing base plate through the rotating assembly. The rotating assembly is convenient to overhaul the opening and closing of the door body, labor is saved, and the use is convenient.

In one embodiment, the manhole access door further comprises a limiting member for limiting a rotation range of the rotating assembly. The limiting part is arranged, so that the overhauled door can be prevented from rotating too much, and the overhaul is convenient.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention, are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention.

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without inventive labor.

Furthermore, the drawings are not to scale of 1:1, and the relative dimensions of the various elements in the drawings are drawn only by way of example and not necessarily to true scale.

FIG. 1 is a diagram illustrating an opened state of a inspection door in a manhole access door according to an embodiment;

FIG. 2 is a diagram illustrating a closed state of a inspection door in the manhole access door according to an embodiment;

FIG. 3 is a schematic structural diagram of a pretensioning structure according to an embodiment;

FIG. 4 is a schematic view of the installation of a screw assembly according to an embodiment.

Description of reference numerals:

10. a pre-tightening structure; 100. a locking member; 110. a guide slope; 112. a small end; 114. a large end; 120. a locking groove; 200. opening and closing the piece; 210. a top rod; 220. a support bar; 300. an elastic member; 400. a limiting ring; 500. a fixing member;

20. a manhole access door; 600. a base plate; 700. repairing the door body; 800. reinforcing the base plate; 900. a rotating assembly; 1000. a limiting member; 1100. a vacuum chuck handle; 1200. sealing rubber strips; 1300. a right angle wrench.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

Referring to fig. 1 and 2, a manhole access door 20 in one embodiment includes a base plate 600, an access door body 700, and a pre-tightening structure 10. Specifically, the pretensioning structure 10 includes a locking member 100, an opening member 200 and an elastic member 300. The opening member 200 has a locking state engaged with the locking member 100 and an opening state disengaged from the locking member 100; the opening unit 200 can elastically act on the locking unit 100 by the elastic member 300; when the opening and closing member 200 is in the open state, the elastic member 300 is in a natural state; when the opening unit 200 is in the locking state, the opening unit 200 is locked to the locking unit 100 by deforming the elastic member 300 and by a restoring force generated by the elastic member 300.

When the pretensioning structure 10 is in use, the opening element 200 is engaged with the locking element 100, so that the opening element 200 can be switched between the locked state and the unlocked state. When the pre-tightening structure 10 needs to be locked, the opening and closing member 200 is driven to a locking state matched with the locking member 100, and at this time, the opening and closing member 200 drives the elastic member 300 to deform, so that the elastic member 300 is in a stressed state, and a restoring force can be transmitted to the opening and closing member 200, thereby facilitating the locking of the opening and closing member 200 and the locking member 100 and forming self-locking. When the locking structure needs to be opened, an external force greater than the restoring force is applied to the opening element 200 to drive the opening element 200 to be disengaged from the locking element 100 to an opened state, and the elastic element 300 is elastically restored to a natural state. The opening and closing member 200 is matched with the elastic member 300, self-locking is realized in the locking state, an external force larger than the restoring force transmitted by the elastic member 300 is required to be given to the opening member in the unlocking process, and the pre-tightening structure 10 is strong in locking stability, simple in structure and good in locking effect.

Preferably, the elastic member 300 is a wave spring.

Referring to fig. 1 and 2, a manhole is provided on a bottom plate 600, an access door 700 is covered on the manhole, a locking member 100 is connected to the access door 700, and the access door is openably and closably connected to the bottom plate 600 through a pre-tightening structure 10. This manhole access door 20 makes this access door can lock on bottom plate 600 through pretension structure 10 to the laminating stability of assurance access door and bridge bottom plate 600 is convenient for close this manhole, avoids access door and bridge bottom plate 600 to take place relative motion.

Referring to fig. 1 and 2, in some embodiments, the manhole access door 20 further includes a reinforcing pad 800, the reinforcing pad 800 is provided with a through hole having a larger aperture than that of the manhole, the reinforcing pad 800 is covered on the bottom plate 600, the manhole is located in the through hole, and the access door 700 is fixedly connected to the bottom plate 600 through the reinforcing pad 800. Set up and strengthen backing plate 800 and play the effect of consolidating the manhole, and be convenient for pretension structure 10 and access door's installation, this strengthen backing plate 800, pretension structure 10 and access door can be integrated and pre-installed, improve site operation efficiency.

Specifically, the sealing rubber strip 1200 is arranged on the outer edge wall of the through hole of the reinforcing base plate 800, so that the sealing performance of closing the access door body 700 can be improved, and the overall stability is improved.

Referring to fig. 1 and 2, in some embodiments, the manhole access door 20 further includes a rotating assembly 900, and the access door body 700 is rotatably connected to the reinforcing pad 800 through the rotating assembly 900. The rotating assembly 900 is arranged, so that the door body 700 can be conveniently opened and closed, manpower is saved, and the use is convenient.

Specifically, this runner assembly 900 includes base, axis of rotation and rotates the seat, and this base fixed connection is in this reinforcing backing plate 800, and this axis of rotation rotates to be connected in this base, and the one end and the maintenance door body 700 fixed connection of this rotation seat, the other end of this rotation seat pass through this axis of rotation and rotate to be connected on the base.

Referring to fig. 1 and 2, in some embodiments, the manhole access door 20 further includes a limiting member 1000, and the limiting member 1000 is used for limiting a rotation range of the rotating assembly 900. Too big, the easy access door rotation range can be avoided through setting up locating part 1000, the easy access. Specifically, the position limiting member 1000 is a position limiting plate, and the position limiting member 1000 is obliquely disposed on the reinforcing backing plate 800.

Specifically, this runner assembly 900, locating part 1000, access door and reinforcing backing plate 800 are assembled in the integration of mill, and welding, simple to operate of mill, welding seam high quality, construction speed are fast, only need weld reinforcing backing plate 800 in bottom plate 600 in the site operation process, and the construction progress is accelerated greatly to the construction convenience.

Preferably, the access door body 700 is made of an aluminum alloy material, so that the weight of the access door body 700 can be reduced.

Referring to fig. 1, in some embodiments, a vacuum chuck handle 1100 is detachably disposed on one side of the access door 700 located outside the steel box girder, so that an operator can push the vacuum chuck handle 1100 on the side of the access door 700 located outside the steel box girder to open the access door 700, and then enter the steel box girder.

Referring to fig. 3, in some embodiments, the pre-tightening structure 10 further includes a limiting ring 400 for being fixedly connected to the bottom plate, one end of the elastic element 300 is fixedly connected to the limiting ring 400, one end of the opening element 200 is disposed through the limiting ring 400 and connected to the other end of the elastic element 300, and the opening element 200 moves relative to the limiting ring 400 to drive the elastic element 300 to switch between the deformed state and the natural state. The elastic member 300 is disposed between the position-limiting ring 400 and the opening member 200, so that when the opening member 200 is switched between the locking state and the opening state, the opening member 200 and the position-limiting ring 400 generate relative movement, thereby driving the elastic member 300 to be switched between the deformation state and the natural state, and the structure is simple and reasonable, and the assembly is convenient.

It should be understood that the elastic member is in a free state, i.e. a length when only receiving gravity, and the elastic member is in a deformed state, i.e. a state of being deformed by the gravity and other external forces, and the elastic length is greater or less than the length in the free state.

Optionally, one end of the elastic member 300 is fixedly connected to the position-limiting ring 400, and the position-limiting ring 400 can be inserted into the opening member 200 or the position-limiting ring 400 is disposed at the bottom of the opening member 200, so that when the opening member 200 and the position-limiting ring 400 move relatively, the elastic member 300 generates restoring force by compression or stretching.

Referring to fig. 3, in some embodiments, the locking member 100 is provided with a guiding inclined plane 110 for guiding and matching with the opening member 200, a small end 112 is located at one end of the guiding inclined plane 110 with a smaller thickness of the locking member 100, a large end 114 is located at one end of the guiding inclined plane 110 with a larger thickness of the locking member 100, and the opening member 200 is switched between an open state and a locked state by moving along the small end 112 to the large end 114; when the opening member 200 is in the open position, the opening member is located at the small end 112, and when the opening member 200 is in the locked position, the opening member is located at the large end 114. When the opening member 200 slides on the guide slope 110, the expansion length of the elastic member 300 is changed synchronously, when the opening member is located at the small end 112, the elastic member 300 is in a natural state, when the opening member slides to the large end 114, the elastic member 300 expands and contracts along with the movement of the opening member 200 and generates an elastic restoring force, and when the opening member 200 is matched and locked with the locking member 100, the elastic member 300 transmits the restoring force to the opening member 200 to form self-locking.

Referring to fig. 3, in some embodiments, the large end 114 is provided with a locking groove 120, and when the opening element 200 is in the locking state, the opening element 200 is locked and matched with the locking groove 120. The locking groove 120 is arranged to enable the opening and closing member 200 to be embedded into the locking groove 120 when in a locking state, when the pre-tightening structure 10 is unlocked, an external force needs to be applied to the opening and closing member 200 to enable the opening and closing member 200 to be separated from the highest height of the locking groove 120, the self-locking stability of the opening and closing member 200 in the locking state is improved, and the opening and closing member 200 is prevented from being separated from the locking member 100 due to vibration.

Specifically, the locking member 100 is disposed in the access door 700, the end of the locking member 100 is horizontally disposed with the access door 700, the middle of the locking member 100 protrudes from the access door 700, and the groove is disposed in the middle of the locking member 100, so that when the opening member 200 is in an open state, the guide inclined surface 110 plays a role of a wire for the opening member 200, and the opening member 200 is convenient to slide on the locking member 100. After the stress is applied to the opening and closing piece 200, the opening and closing piece 200 can be embedded into the groove through the guide inclined plane 110, so that the opening and closing piece 200 is switched to be in a locking state, the opening and closing piece 200 is subjected to restoring force transmitted by the elastic piece 300 and acts on the maintenance door body 700 to be locked, and the maintenance door body 700 is prevented from being opened.

Alternatively, the locking member 100 is configured as a guide bar having two lower ends and a middle higher end, the opening member 200 can slide on the guide slope 110 by driving the opening member 200, and when the opening member 200 is inserted into the groove, the opening member 200 is in a locked state, and when the opening member 200 is driven to slide to the two ends of the locking member 100, the opening member 200 is in an unlocked state.

Referring to fig. 4, in some embodiments, the opening and closing member 200 is a T-shaped rotating rod, the opening and closing member 200 includes a top rod 210 and a supporting rod 220, one end of the supporting rod 220 is connected to the middle portion of the top rod 210, the other end of the supporting rod 220 penetrates through the limiting ring 400 and is connected to the elastic member 300, and the top rod 210 is rotatably connected to the locking member 100, so that the opening and closing member 200 is openably and closably disposed on the locking member 100. The supporting rod 220, the elastic member 300, the top rod 210, the locking member 100 and the opening and closing member 200 can drive the top rod 210 to rotate by rotating the supporting rod 220, and are matched with the locking member 100 through the guide inclined plane 110, so that the structure is simple and reasonable.

Preferably, the number of the locking pieces 100 is two, the locking pieces 100 are arranged as guide strips, the two locking pieces 100 are arranged in the access door body 700 in parallel and at intervals, when the opening and closing piece 200 is in an opening state, the axial direction of the top rod 210 is parallel to the guide strips and is embedded between the two guide strips, and at this time, the access door body 700 can be normally opened. When the driving support rod 220 rotates, the push rod 210 is driven to rotate at the same time, the push rod 210 slides on the locking piece 100 through the guiding effect of the guiding inclined plane 110 until the opening and closing piece 200 is embedded in the groove, the elastic piece 300 transmits restoring force to lock the opening and closing piece 200, the maintenance door body 700 receives pressing force transmitted by the opening and closing piece 200 at the moment, the opening and closing piece 200 locks the maintenance door body 700, and when the bridge vibrates up and down, the maintenance door body 700 can be prevented from being opened. The groove is opened in the middle of the locking member 100, the opening member 200 is inserted into the groove by rotating 90 ° in the opening state, and the opening state is recovered by rotating 90 ° in the locking state.

Referring to fig. 3, in some embodiments, the pre-tightening structure 10 further includes a fixing member 500, the supporting rod 220 sequentially penetrates through the limiting ring 400, the elastic member 300 and the fixing member 500 and is fixedly connected to the fixing member 500, the opening and closing member 200 is connected to the elastic member 300 through the fixing member 500, and the supporting rod 220 is in clearance fit with both the limiting ring 400 and the elastic member 300; when the push rod 210 rotates to the locking groove 120, the fixing member 500 is driven to move towards the direction close to the elastic member 300, and the elastic member 300 is compressed by a force and transmits a restoring force to the fixing member 500, so that the push rod 210 is locked in the locking groove 120 by the force; when the push rod 210 is released from the locking groove 120, the fixing member 500 is moved away from the elastic member 300 by the restoring force to release the opening member 200 from the locking member 100. The fixing member 500 is disposed to facilitate the elastic member 300 to be elastically connected with the opening member 200, and the elastic member 300 is disposed between the limiting ring 400 and the fixing member 500, so that when the opening member 200 is in the locking state, the fixing member 500 moves towards the elastic member 300 to compress the elastic member 300, so that the fixing member 500 receives the restoring force transmitted by the elastic member 300, and the opening member 200 is forced to be stably self-locked in the locking groove 120.

Preferably, the fixing member 500 is a limit nut, the supporting rod 220 is provided with a thread adapted to the limit nut, and the supporting rod 220 is in threaded fastening fit with the limit nut. When the assembly is performed, the stop collar 400, the elastic member 300 and the fixing member 500 are sequentially introduced into the support rod 220, and the fixing member 500 is screwed to assemble a spiral assembly.

Specifically, the bottom plate 600 and the reinforcing backing plate 800 are provided with assembling holes for assembling the spiral component, during assembling, the limiting ring 400 is fixedly connected to the reinforcing backing plate 800, at this time, one end of the fixing member 500 fixedly connected to the support rod 220 extends out of the bottom plate 600 by a certain length through the assembling holes, and the length between the limiting ring 400 and the fixing member 500 is just equal to the free length of the elastic member 300.

Referring to fig. 3, in some embodiments, the pretensioning structure 10 further includes a right angle wrench 1300 for rotating the support rod 220, wherein an end of the support rod 220 away from the top rod 210 is provided with a mounting hole, and the right angle wrench 1300 is detachably connected to the mounting hole. One end of the right angle wrench 1300 is inserted into the mounting hole, the other end of the right angle wrench 1300 is driven to rotate the support rod 220, the rotating force arm can be increased through the right angle wrench 1300, and one end of the support rod 220 is driven to switch the opening and closing member 200 to be in an opening state and a locking state.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only show some embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.