Safety protection device for engineering construction

Abstract

The invention relates to the technical field of engineering construction safety devices, and discloses a safety protection device for engineering construction.The safety protection device comprises a protective barrier, an expansion structure, a lifting rod, a splicing rod and fixates.The protective barrier is placed in the middle of a construction channel and transversely extends after the expansion structure is pulled open, and the fixatesare placed on the two sides of a construction channel wall; when a channel is closed, a special screw is used for rotating and tightening a fastening bolt, two clamps are pulled to get close to clamp a construction channel wall, and due to the fact that three triangular grooves in a rotating structure are of a special structure formed in a surrounding array mode, the special screw is needed to rotate. After firm installation, non-constructors are prevented from disassembling and intruding.

Description

Technical Field

[0001] The invention relates to the technical field of engineering construction safety devices, in particular to a safety protection device for engineering construction. Background Art

[0002] The safety protection devices for engineering construction mainly include edge protection devices, hole protection devices, foundation pit engineering safety protection devices and other special devices. The use of these safety protection devices can effectively reduce the risks in the construction process and ensure the safety of the workers. Among them, edge protection is mainly to protect the construction passage to prevent non-construction personnel from entering the construction site, and at the same time prevent construction personnel from entering the dangerous area through the construction passage without authorization. Edge guardrails are usually retractable to adjust the size of the protection range. To ensure the stability of the edge guardrails, they are fixed to the walls of the construction passage using threaded holes, making it difficult to move the guardrails. This improves their stability while better preventing intrusion by non-construction personnel. Since the threaded drilling fixation requires a larger volume to be better fixed on the wall, it is easy to leave larger threaded holes on the wall, which will cause greater damage to the passage wall. In addition, the threaded fixation can be easily unscrewed and disassembled by intruders, and its safety protection is poor. Summary of the invention

[0003] The present invention provides a safety protection device for engineering construction, which overcomes the shortcomings described in the background technology.

[0004] The technical solution adopted by the present invention to solve its technical problem is: A safety protection device for engineering construction, characterized in that it comprises a guardrail, an expansion structure, a lifting rod, a splicing rod, and a fixer, wherein the lifting rod and the guardrail are each provided with two and form two groups for reverse movement, a clamping structure is provided in the guardrail, and after the lifting rod and the guardrail slide longitudinally, the clamping structure is pressed so that the guardrail supports and fixes the lifting rod, the two groups of lifting rods and the guardrail are pulled apart and extended laterally from each other, eight fixers are provided, symmetrically distributed in the middle position outside the lifting rod and the guardrail, and the upper two fixers are connected to the guardrail, and the lower two fixers are connected to the guardrail, and the fixers are arranged in a straight line after the guardrail and the lifting rod are pulled apart and extended and clamped in the wall of the construction channel; The fixer is provided with a connecting block, a hinge rod, a fastening bolt, a clamp, a fixture and a rubber block. The two fixtures are hinged and clamped in the connecting block through the hinge rod, and the two fixtures are passed through and tightened by the fastening bolts to clamp them close to each other, so that the clamps on the inner sides of the two fixtures clamp the two sides of the wall, and the fastening bolts use special screws to penetrate into the interior and rotate to pull the fixtures close to and clamp the wall.

[0005] A better technical solution: the fastening bolt is provided with a ball, a rotating structure, a pull plate, an outer ring plate, a hollow rod, and a metal rod. The ball is arranged at the outermost end of the metal rod and abuts against the middle side of the pull plate. The rotating structure moves threadedly in the middle position of the hollow rod, and the metal rod is fixed at the inner end of the rotating structure and moves following the thread rotation. When the special screw enters the rotating structure position from the metal rod, it rotates, driving the rotating structure to rotate and move in the inner thread of the hollow rod, and pulling the ball at the left end of the metal rod to move left, so that the pull plate is translated toward the center in the hollow rod, so that the pull plate and the outer ring plate are respectively pressed and pulled inward on the outside of the two clamps.

[0006] A preferred technical solution: the rotating structure is provided with a force ring and triangular grooves, a threaded ring is provided on the outer side of the force ring, and the three triangular grooves are arranged in an annular array on the right side of the inner side of the force ring.

[0007] A better technical solution: the middle of the special screw is circular, and the outer periphery of the special screw is provided with three triangular bars corresponding to the triangular grooves and of the same size. The special screw penetrates into the hollow rod and matches the triangular grooves in the force ring, and the outer end of the special screw is provided with a handle for screwing.

[0008] A better technical solution: the pull plate is provided with a stopper, a load-bearing block, and an arc groove. There are two connecting rods connected to the stopper on the outside of the load-bearing block, and the connecting rods correspond to the two sliding grooves in the hollow rod. When the ball is pulled by the metal rod, the ball presses against the arc groove in the middle of the load-bearing block, and pulls the load-bearing block and the stopper to rotate in the hollow rod, so that the stopper presses against the outside of the clamp and pulls it.

[0009] A better technical solution: the guardrail is provided with a support block, a first clamping block, a first sliding rod, and a sliding rail. The first clamping block is arranged at the outer end of the expansion structure and is clamped inside the first sliding rod. The support block is arranged on the side of the first clamping block, and the clamping structure in the first sliding rod passes through the support block. When the first sliding rod slides with the lifting rod, the clamping structure is pulled upward to make it abut against the support block, and the support block is pushed outward to contact the lifting rod. Under the lateral pressure of the lifting rod, the support block is pressed and the clamping structure is clamped in reverse, so that the support block presses against the second sliding rod after sliding.

[0010] A better technical solution: the lifting rod is provided with a second sliding rod, a sliding bar, a second clamping block, and a force-bearing block. The second sliding rod slides in cooperation with the sliding rail through the sliding bar on the side. The force-bearing block is arranged on the side of the second clamping block. When the support block is pushed out, the force-bearing block presses against the corresponding part of the support block laterally under the gravity of the second sliding rod.

[0011] A better technical solution: the support block includes a connecting plate, an inclined block, an elastic rod, and a slot. The slot is triangular in shape and is arranged in the middle of the inclined surface of the inclined block. The elastic rod is arranged on the side of the upper end of the connecting plate and drives the elastic rod hinge to rotate. A circular hole is provided in the middle of the upper surface of the connecting plate, and the locking structure passes through the circular hole. When the locking structure is lifted up, the locking structure slides upward on the side of the inclined block and pushes out the inclined block.

[0012] A better technical solution: the locking structure includes a round rod and a triangular plate, and the triangular plates are arranged equidistantly on the side of the round rod. The round rod passes through the circular hole in the connecting plate and is squeezed against the inclined block. When the round rod moves upward, the triangular plate presses against the inclined block to push it outward, and is squeezed in the opposite direction by the inclined block under the pressure of the lifting rod. When released, the round rod is pressed to cause the inclined block to rotate toward the connecting plate and break away from the support of the force-bearing block.

[0013] Compared with the prior art, this technical solution has the following advantages: In the present invention, the guardrail is placed in the middle of the construction channel, and the expansion structure is pulled open to extend it laterally, so that the fixer is placed on both sides of the wall of the construction channel, and the lifting rod is pushed to slide upward on the side of the guardrail. When the channel is closed, a special screw is used to rotate and tighten the fastening bolt, and the two clamps are pulled close to clamp the wall of the construction channel. In addition, since the three triangular grooves in the rotating structure are a special structure formed by a surrounding array, a special screw is required to rotate, and after the installation is firmly installed, it is prevented from being dismantled and intruded by non-construction personnel.

[0014] In the present invention, when the lifting rod slides upward on the side of the guardrail, the upper fixer moves with the lifting rod, and the four fixers are kept in a straight line on the same side. When the lifting rod is pulled to the size of the construction channel, it is supported by the fixed support, and the gravity of the lifting rod squeezes the reverse clamping engagement structure to keep the guardrail and the lifting rod in a staggered state after being pulled apart. After the fixer clamps the wall, the installation of the lifting rod and the guardrail will not damage the wall structure, and the guardrail and the fixer above the lifting rod and the fixer below are clamped in a straight line. When non-construction personnel break in, they are dislocated with each other so that the lifting rod and the guardrail on the left and right sides have the same bearing force when clamped and fixed to the wall, making the lifting rod and the guardrail more stable when connected and fixed by the fixer. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0016] Figure 1 This is an overall diagram of the present invention.

[0017] Figure 2 A plan view of the fixator.

[0018] Figure 3 It is a plan view of the hinge rod.

[0019] Figure 4 It is a plan view of the rotating structure.

[0020] Figure 5 It is a three-dimensional schematic diagram of the pull plate and the hollow rod.

[0021] Figure 6 This is a partial enlarged schematic diagram of the protective railing.

[0022] Figure 7 A partial enlarged schematic diagram of the lifting rod.

[0023] Figure 8 A three-dimensional schematic diagram of the support block.

[0024] Fig. 9 It is a three-dimensional schematic diagram of the locking structure.

[0025] In the figure: guardrail-1, expansion structure-2, lifting rod-3, splicing rod-4, and fixer-5.

[0026] Connecting block 51, hinge rod 52, fastening bolt 53, clamp plate 54, clamp 55, rubber block 56, ball 531, rotating structure 532, pull plate 533, outer ring plate 534, hollow rod 535, metal rod 536.

[0027] Force ring-5321, triangular groove-5322, stop block-5331, load-bearing block-5332, arc groove-5333.

[0028] Support block 121, first clamping block 122, first sliding bar 123, sliding rail 124, second sliding bar 31, sliding bar 32, second clamping block 33, force bearing block 34.

[0029] Connecting plate 1211, inclined block 1212, elastic rod 1213, and slot 1214.

[0030] The engaging structure 11, the round rod 111 and the triangular plate 112. DETAILED DESCRIPTION

[0031] like Figures 1 to 9As shown, the present invention proposes a safety protection device for engineering construction, including a guardrail 1, an expansion structure 2, a lifting rod 3, a splicing rod 4, and a fixer 5. The lifting rod 3 and the guardrail 1 are each provided with two and form two groups for reverse movement. A clamping structure 11 is provided in the guardrail 1, and the clamping structure 11 is pressed after the lifting rod 3 and the guardrail 1 slide longitudinally, so that the guardrail 1 supports and fixes the lifting rod 3. The two groups of lifting rods 3 and the guardrail 1 are pulled apart and extended laterally from each other. There are eight fixers 5, which are symmetrically distributed in the middle position outside the lifting rod 3 and the guardrail 1, and the upper two fixers 5 are connected to the lifting rod 3, and the lower two fixers 5 are connected to the guardrail 1. The fixers 5 are arranged in a straight line after the guardrail 1 and the lifting rod 3 are pulled apart and extended, and are clamped in the wall of the construction channel; The fixer 5 is provided with a connecting block 51, a hinge rod 52, a fastening bolt 53, a clamp 54, a clamp 55, and a rubber block 56. The two clamps 55 are hinged and clamped in the connecting block 51 through the hinge rod 52, and the two clamps 55 are penetrated by the fastening bolt 53 and tightened to clamp each other close to each other, so that the clamps 54 on the inner side of the two clamps 55 clamp the two sides of the wall, and the fastening bolt 53 uses a special screw to penetrate into the interior and rotate to pull the clamp 55 close to and clamp the wall.

[0032] The rubber block 56 has a characteristic of high friction and is elastically compressed after being clamped on the wall, thus having a good elastic fixing effect. After the fixer 5 clamps the wall, the guardrail 1 and the expansion structure 2 are not easily pulled apart laterally.

[0033] Among them, the fastening bolt 53 is provided with a ball 531, a rotating structure 532, a pull plate 533, an outer ring plate 534, a hollow rod 535, and a metal rod 536. The ball 531 is arranged at the outermost end of the metal rod 536 and abuts against the middle side of the pull plate 533. The rotating structure 532 moves threadedly in the middle position of the hollow rod 535, and the metal rod 536 is fixed at the inner end of the rotating structure 532 and rotates with the thread. When the special screw enters the rotating structure 532 position from the metal rod 536, it rotates, driving the rotating structure 532 to rotate and move in the inner thread of the hollow rod 535, and pulling the ball 531 at the left end of the metal rod 536 to move leftward, so that the pull plate 533 is translated toward the center in the hollow rod 535, so the pull plate 533 and the outer ring plate 534 are respectively pressed and pulled inward on the outside of the two clamps 55.

[0034] Among them, the rotating structure 532 is provided with a force ring 5321 and a triangular groove 5322, and a threaded ring is provided on the outside of the force ring 5321. The three triangular grooves 5322 are arranged in a circular array on the right side of the inner side of the force ring 5321, and a threaded groove is provided in the hollow rod 535 to match the threaded ring on the outside of the force ring 5321. After the triangular groove 5322 is rotated by a special screw, the threaded ring on the outside of the force ring 5321 is driven to rotate and translate in the hollow rod 535, thereby shortening the distance between the ball 531 and the outer ring plate 534, thereby realizing the close clamping of the clamp 55.

[0035] The middle of the special screw is circular, and the outer periphery of the special screw is provided with three triangular bars corresponding to the triangular groove 5322 and of the same size. The special screw penetrates into the hollow rod 535 and matches the triangular groove 5322 in the force ring 5321, and a handle for screwing is provided at the outer end of the special screw.

[0036] Among them, the pulling plate 533 is provided with a stopper 5331, a load-bearing block 5332, and an arc groove 5333. There are two connecting rods connecting the stopper 5331 on the outside of the load-bearing block 5332, and the connecting rods correspond to the two sliding grooves in the hollow rod 535. When the ball 531 is pulled by the metal rod 536, the ball 531 abuts against the arc groove 5333 in the middle of the load-bearing block 5332, and pulls the load-bearing block 5332 and the stopper 5331 to rotate in the hollow rod 535, so that the stopper 5331 presses against the outside of the clamp 55 and pulls it.

[0037] In addition, the guardrail 1 is provided with a support block 121, a first clamping block 122, a first sliding rod 123, and a sliding rail 124. The first clamping block 122 is arranged at the outer end of the expansion structure 2 and is clamped inside the first sliding rod 123. The support block 121 is arranged on the side of the first clamping block 122, and the clamping structure 11 in the first sliding rod 123 passes through the support block 121. When the first sliding rod 123 slides with the lifting rod 3, the clamping structure 11 is pulled upward to make it abut against the support block 121, and the support block 121 is pushed outward to contact the lifting rod 3. Under the lateral pressure of the lifting rod 3, the support block 121 is abutted and the clamping structure 11 is clamped in reverse, so that the support block 121 supports the second sliding rod 31 after sliding.

[0038] Among them, the lifting rod 3 is provided with a second sliding rod 31, a sliding bar 32, a second clamping block 33, and a force block 34. The second sliding rod 31 slides in cooperation with the sliding rail 124 through the sliding bar 32 on the side. The force block 34 is arranged on the side of the second clamping block 33. When the support block 121 is pushed out, the force block 34 presses against the corresponding position of the support block 121 laterally under the gravity of the second sliding rod 31.

[0039] Among them, the support block 121 includes a connecting plate 1211, an inclined block 1212, an elastic rod 1213, and a slot 1214. The slot 1214 is triangular in shape and is arranged in the middle of the inclined surface of the inclined block 1212. The elastic rod 1213 is arranged on the upper side of the connecting plate 1211 and drives the elastic rod 1213 to hinge and rotate. A circular hole is provided in the middle of the upper surface of the connecting plate 1211, and the locking structure 11 passes through the circular hole. When the locking structure 11 is lifted up, the locking structure 11 slides upward on the side of the inclined block 1212 and pushes out the inclined block 1212.

[0040] Among them, the locking structure 11 includes a round rod 111 and a triangular plate 112. The triangular plate 112 is arranged equidistantly on the side of the round rod 111. The round rod 111 passes through the circular hole in the connecting plate 1211 and is squeezed by the inclined block 1212. When the round rod 111 moves upward, the triangular plate 112 presses against the inclined block 1212 to push it outward, and is reversely squeezed by the inclined block 1212 under the pressure of the lifting rod 3. When released, the round rod 111 is pressed to make the inclined block 1212 rotate toward the connecting plate 1211 and break away from the support of the force-bearing block 34.

[0041] In the present invention, the two groups of guardrails 1 and lifting rods 3 are pulled apart horizontally to extend the expansion structure 2 horizontally, so that the fixer 5 is placed on both sides of the construction channel wall, and the lifting rods 3 are pushed to slide upward on the side of the guardrails 1. After the upper end of the lifting rods 3 touches the top of the channel, the engaging structure 11 is lifted upward, thereby driving the inclined block 1212 to rotate counterclockwise outward with the elastic rod 1213, so that the engaging structure 11 pushes the support block 121 outward to block the force-bearing block 34 in the lifting rod 3, and makes the force-bearing block 34 fit in the card slot 1214. At this time, the force pushing the lifting rod 3 upward is released. Under the gravity of the lifting rod 3, the gravity accumulated in the expansion structure 2 connected to the second card block 33 is blocked by the force-bearing block 34. The inclined block 1212 in the supporting block 121 is squeezed laterally, and the inclined block 1212 presses the triangular plate 112 in the locking structure 11 against the side of the connecting plate 1211 under the lateral squeezing force. The gravity forms a reverse squeezing force to clamp the triangular plate 112, so that the lifted round rod 111 remains in a fixed state, and the sliding of the lifting rod 3 is supported and fixed, forming the effect of extending the height of the guardrail 1 and the lifting rod 3, and the construction channel can be closed according to the size of the channel. At the same time, eight fixers 5 are symmetrically distributed on the outside of the guardrail 1 and the lifting rod 3 and are extended and pulled, so that the fixers 5 are distributed in a straight line on the left and right sides of the wall, and are clamped on the channel wall by the fixers 5 to avoid damage to the wall.

[0042] In the present invention, after the passage is completely closed, a special screw is used to rotate and tighten the fastening bolt 53, and the two clamps 55 are pulled close together, so that the rubber blocks 56 on the sides of the clamping plate 54 clamp the two sides of the wall. In addition, since the three triangular grooves 5322 in the rotating structure 532 are a special structure formed by a surrounding array, a special screw is required to rotate, and after the installation is firm, it is prevented from being dismantled and intruded by non-construction personnel.

[0043] In the present invention, when the lifting rod 3 slides upward on the side of the guardrail 1, the upper fixer 5 moves with the lifting rod 3, and the four fixers 5 are kept in a straight line on the same side. When the lifting rod 3 is pulled open to the size of the construction channel, it is fixed and supported by 121, so that the pulled-open guardrail 1 and the lifting rod 3 are kept in a staggered state, and the guardrail 1 and the fixing device 5 above the lifting rod 3 and the fixing device 5 below are clamped in a straight line. When non-construction personnel break in, they are dislocated with each other so that the lifting rod 3 and the guardrail 1 on the left and right sides have the same bearing force when clamped and fixed on the wall, so that the lifting rod 3 and the guardrail 1 are more stable when connected and fixed by the fixing device 5.

[0044] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A safety protection device for engineering construction, characterized in that: The invention comprises a guardrail (1), an expansion structure (2), a lifting rod (3), a splicing rod (4), and a fixing device (5), wherein two lifting rods (3) and two guardrails (1) are provided respectively and form two groups for reverse movement, a locking structure (11) is provided inside the guardrail (1), and after the lifting rod (3) and the guardrail (1) slide longitudinally, the locking structure (11) is pressed so that the guardrail (1) supports and fixes the lifting rod (3), and the two groups of lifting rods (3) and the guardrail (1) are extended laterally from each other, and eight fixing devices (5) are provided and symmetrically distributed at the middle position outside the lifting rod (3) and the guardrail (1), and the upper two fixing devices (5) are connected to (3), and the lower two fixing devices (5) are connected to the guardrail (1), and the fixing devices (5) are arranged in a straight line after the guardrail (1) and the lifting rod (3) are extended and clamped in the wall of the construction channel; The fixing device (5) is provided with a connecting block (51), a hinge rod (52), a fastening bolt (53), a clamping plate (54), a clamp (55), and a rubber block (56). The two clamps (55) are hinged and clamped in the connecting block (51) through the hinge rod (52), and the two clamps (55) are passed through and tightened by the fastening bolt (53) to be close to each other and clamped, so that the clamping plates (54) inside the two clamps (55) clamp the two sides of the wall, and the fastening bolt (53) is penetrated into the inside and rotated by a special screw to pull the clamp (55) close to and clamp the wall.

2. A safety protection device for engineering construction according to claim 1, characterized in that: The fastening bolt (53) is provided with a ball (531), a rotating structure (532), a pull plate (533), an outer ring plate (534), a hollow rod (535), and a metal rod (536); the ball (531) is arranged at the outermost end of the metal rod (536) against the middle side of the pull plate (533); the rotating structure (532) is threadedly moved at the middle position of the hollow rod (535); and the metal rod (536) is fixed at the inner end of the rotating structure (532) and at the bottom thereof. As the thread rotates, when the special screw enters the rotating structure (532) from the metal rod (536) and rotates, the rotating structure (532) is driven to rotate in the inner thread of the hollow rod (535), and the ball (531) at the left end of the metal rod (536) is pulled to the left, so that the pull plate (533) moves toward the center in the hollow rod (535), so that the pull plate (533) and the outer ring plate (534) are respectively pressed and pulled inward on the outside of the two clamps (55).

3. A safety protection device for engineering construction according to claim 2, characterized in that: The rotating structure (532) is provided with a force ring (5321) and a triangular groove (5322); a threaded ring is provided on the outside of the force ring (5321); and a ring array of three triangular grooves (5322) is located on the right side of the inside of the force ring (5321).

4. A safety protection device for engineering construction according to any one of claims 1 to 3, characterized in that: The middle of the special screw is in a circular state, and three triangular bars of the same size and corresponding to the triangular grooves (5322) are arranged on the periphery of the special screw. The special screw penetrates into the hollow rod (535) and coincides with the triangular grooves (5322) in the force ring (5321).

5. The safety protection device for engineering construction according to claim 2 is characterized in that: The pulling plate (533) is provided with a stopper (5331), a load-bearing block (5332), and an arc groove (5333). Two connecting rods connected to the stopper (5331) are provided on the outside of the load-bearing block (5332), and the connecting rods correspond to two sliding grooves in the hollow rod (535). When the ball (531) is pulled by the metal rod (536), the ball (531) abuts against the arc groove (5333) in the middle of the load-bearing block (5332), and pulls the load-bearing block (5332) and the stopper (5331) to rotate in the hollow rod (535), so that the stopper (5331) presses against the outside of the clamp (55) and pulls.

6. The safety protection device for engineering construction according to claim 1 is characterized in that: The guardrail (1) is provided with a support block (121), a first clamping block (122), a first sliding rod (123), and a sliding rail (124); the first clamping block (122) is arranged at the outer end of the expansion structure (2) and is clamped inside the first sliding rod (123); the support block (121) is arranged on the side of the first clamping block (122), and the clamping structure (11) in the first sliding rod (123) passes through the support block (121); when the first sliding rod (123) slides with the lifting rod (3), the clamping structure (11) is pulled upward to abut against the support block (121), and the support block (121) is pushed outward to contact the lifting rod (3); under the lateral pressure of the lifting rod (3), the support block (121) is abutted and the clamping structure (11) is clamped in reverse, so that the support block (121) abuts against the second sliding rod (31) after sliding.

7. The safety protection device for engineering construction according to claim 1 is characterized in that: The lifting rod (3) is provided with a second sliding rod (31), a sliding bar (32), a second clamping block (33), and a force-bearing block (34); the second sliding rod (31) is slidably matched in the sliding rail (124) through the sliding bar (32) on the side; the force-bearing block (34) is arranged on the side of the second clamping block (33); when the supporting block (121) is pushed out, the force-bearing block (34) is laterally pressed against the corresponding position of the supporting block (121) under the gravity of the second sliding rod (31).

8. The safety protection device for engineering construction according to claim 6 is characterized in that: The support block (121) comprises a connecting plate (1211), an inclined block (1212), an elastic rod (1213), and a slot (1214); the slot (1214) is triangular in shape and is arranged in the middle of the inclined surface of the inclined block (1212); the elastic rod (1213) is arranged on the side surface of the upper end of the connecting plate (1211) and drives the elastic rod (1213) to hinge and rotate; a circular hole is provided in the middle of the upper surface of the connecting plate (1211), and the locking structure (11) passes through the circular hole; when the locking structure (11) is lifted upward, the locking structure (11) slides upward on the side of the inclined block (1212) and pushes out of the inclined block (1212).

9. A safety protection device for engineering construction according to any one of claims 1 to 8, characterized in that: The engaging structure (11) comprises a round rod (111) and a triangular plate (112). The triangular plates (112) are arranged at equal intervals on the side of the round rod (111). The round rod (111) passes through a circular hole in a connecting plate (1211) and is pressed against an inclined block (1212). When the round rod (111) moves upward, the triangular plate (112) presses against the inclined block (1212) to push it outward and is reversely pressed by the inclined block (1212) under the pressure of the lifting rod (3). When released, the round rod (111) is pressed to cause the inclined block (1212) to rotate toward the connecting plate (1211) and to separate from the support of the force-bearing block (34).

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