CN116146095A

CN116146095A - Ladder stand

Info

Publication number: CN116146095A
Application number: CN202310141348.1A
Authority: CN
Inventors: 赵匀添
Original assignee: Truking Watertown Pharmaceutical Equipment Co Ltd
Current assignee: Truking Watertown Pharmaceutical Equipment Co Ltd
Priority date: 2023-02-21
Filing date: 2023-02-21
Publication date: 2023-05-23

Abstract

The application relates to a cat ladder, the cat ladder includes: and the bracket and the rollover prevention assembly. The support is provided with a plurality of pedals which are sequentially arranged at intervals from bottom to top, and at least one roller is arranged at the bottom of the support. The rollover prevention assembly comprises a support rod which is slidably connected to the support, and a positioning support leg which is connected with the support rod and can be adjusted in a lifting manner. Because the bottom of support is equipped with the gyro wheel, be convenient for adjust the position of cat ladder in a flexible way according to actual demand. After the ladder stand is moved to the target position, the support rod is outwards extended to the target position, and then the support rod is lifted, adjusted and positioned, so that the support rod falls and is mutually abutted with the ground, the support is fixed on the ground through the rollover prevention assembly, rollover prevention effect is achieved, and shaking and movement in the operation process can be avoided. After the cat ladder is firmly fixed on the ground, a worker can climb up a preset height position by means of the pedal to perform related operation, so that safety is improved, and the cat ladder can be flexibly used according to actual requirements.

Description

Ladder stand

Technical Field

The invention relates to the technical field of tools for life, in particular to a cat ladder.

Background

In steel construction engineering construction, the cat ladder is an important tool for constructing an upper working surface and a lower working surface. The traditional cat ladder has no safety protection measures, the stability of the movable steps is poor under the condition of narrower width, and operators are easy to turn over when operating on the movable steps, so that the safety of the climbing operation of the operators cannot be met, and the potential safety hazard is large; the safety can not meet the requirements of government departments, thereby causing the phenomenon of shutdown rectification and affecting the construction progress. In addition, in the steel structure installation, the cat ladder turnover number of times is many, also has to weld the cat ladder on being fixed in the steel structure, although can improve stability, nevertheless make reuse rate low, lead to construction cost high and construction progress slow.

Disclosure of Invention

Based on this, it is necessary to overcome the defects of the prior art, and to provide a ladder stand which can improve stability, prevent rollover, improve safety and be flexibly used.

The technical scheme is as follows: a crawling ladder, the crawling ladder comprising:

the support is provided with a plurality of pedals which are sequentially arranged at intervals from bottom to top, and the bottom of the support is provided with at least one roller; and

the side-turning prevention assembly comprises a support rod which is slidably connected to the support, and a positioning support leg which is connected with the support rod and can be adjusted in a lifting manner.

In one embodiment, the number of rollover prevention assemblies is at least two.

In one embodiment, a plurality of pedals are arranged on the front surface of the bracket, and at least one rollover prevention assembly is respectively arranged on two opposite side surfaces of the bracket.

In one embodiment, at least two rollover prevention assemblies are respectively arranged on two opposite side surfaces of the support, and the rollover prevention assemblies on one side surface of the support and the rollover prevention assemblies on the other side surface correspond to each other in position.

In one embodiment, the rollover prevention assembly further includes a locking assembly for locking and securing the support bar to the bracket.

In one embodiment, a sliding sleeve is arranged at the bottom of the bracket, and the supporting rod is slidably arranged in the sliding sleeve in a penetrating manner; and/or the bottom of the bracket is provided with a sliding part, the supporting rod is provided with a sliding groove matched with the sliding part, and the sliding part is arranged in the sliding groove.

In one embodiment, the locking assembly comprises a connecting rod, a wear pad, an elastic clamping pad, and a locking nut; the side wall of sliding sleeve is provided with waist type hole along the axial direction extension, the connecting rod wears to locate in the waist type hole and with the bracing piece links to each other, just the connecting rod can be followed waist type hole activity, be equipped with on the outer wall of connecting rod with lock nut suited screw thread, wear pad elasticity card pad with lock nut overlaps in proper order establish connect in on the connecting rod, and be located the outside of sliding sleeve.

In one embodiment, the top end of the positioning support leg is provided with a screw, the end part of the support rod is provided with a connecting part, the connecting part is provided with a screw hole corresponding to the screw, and the screw is penetrated in the screw hole; the bottom of location stabilizer blade is equipped with the baseboard.

In one embodiment, the ladder further comprises a controller, and the rollover prevention assembly further comprises a pushing mechanism and a lifting mechanism; the pushing mechanism and the lifting mechanism are respectively and electrically connected with the controller; the pushing mechanism is connected to the bracket and used for driving the supporting rod to extend out of the bracket or retract into the bracket; the lifting mechanism is connected to the supporting rod and is further connected with the positioning support leg and used for driving the positioning support leg to move up and down.

In one embodiment, the ladder further comprises a guardrail disposed on the support; the top of the bracket is provided with a bearing plate, the guardrail comprises a first protective fence arranged on two opposite sides of the pedal and a second protective fence arranged on the bearing plate, and the second protective fence is connected with the first protective fence; one side of the carrier plate corresponds to the position of the pedal, and the other sides of the carrier plate are surrounded by the second guard rail.

According to the crawling ladder, the rollers are arranged at the bottoms of the supports, so that the positions of the crawling ladder can be flexibly adjusted according to actual requirements. After the ladder stand is moved to a target position (for example, beside a storage tank to be maintained), the support rod is outwards extended to a proper position, and then the support rod is lifted, adjusted and positioned to enable the support rod to fall and mutually abut against the ground, so that the support is fixed on the ground through the rollover prevention assembly, rollover prevention is achieved, and shaking and movement in the operation process can be avoided. After the cat ladder is firmly fixed on the ground, a worker can climb up a preset height position by means of the pedal to perform related operation, so that safety is improved, and the cat ladder can be flexibly used according to actual requirements.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application, illustrate and explain the application and are not to be construed as limiting the application.

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed 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 application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural view of a ladder stand according to an embodiment of the present disclosure;

FIG. 2 is an enlarged schematic view of the structure shown in FIG. 1 at A;

FIG. 3 is a top view of the structure shown in FIG. 1;

FIG. 4 is a schematic cross-sectional view of the structure of FIG. 3 at B-B;

FIG. 5 is an enlarged schematic view of FIG. 4 at C;

fig. 6 is a schematic cross-sectional view of fig. 5 at D-D.

10. A bracket; 11. a pedal; 12. a roller; 13. a front face; 14. a side surface; 15. a sliding sleeve; 151. a waist-shaped hole; 16. a carrying plate; 17. a bottom plate; 20. an anti-rollover assembly; 21. a support rod; 211. a connection part; 212. square tube beam; 22. positioning support legs; 221. a screw; 222. a baseboard; 23. a locking assembly; 231. a connecting rod; 232. a wear pad; 233. an elastic clamping pad; 234. a lock nut; 30. guard bars; 31. a first guard rail; 32. and a second guard rail.

Detailed Description

In order to make the above objects, features and advantages of the present application more 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 application. This application is, however, susceptible of embodiment in many other forms than those described herein and similar modifications can be made by those skilled in the art without departing from the spirit of the application, and therefore the application is not to be limited to the specific embodiments disclosed below.

Referring to fig. 1 to 3, fig. 1 shows a schematic structural view of a ladder according to an embodiment of the present application, fig. 2 shows an enlarged schematic structural view of the structure shown in fig. 1 at a, and fig. 3 shows a top view of the structure shown in fig. 1. An embodiment of the present application provides a cat ladder, cat ladder includes: bracket 10 and rollover prevention assembly 20. The support 10 is provided with a plurality of pedals 11 which are sequentially arranged at intervals from bottom to top, and at least one roller 12 is arranged at the bottom of the support 10. The rollover prevention assembly 20 includes a support bar 21 slidably coupled to the stand 10, and a lift-adjustable positioning leg 22 coupled to the support bar 21.

According to the ladder stand, the rollers 12 are arranged at the bottom of the support 10, so that the position of the ladder stand can be flexibly adjusted according to actual requirements. After the ladder stand is moved to a target position (for example, beside a storage tank to be maintained), the support rod 21 is extended outwards to a proper position, and then the positioning support leg 22 is lifted and adjusted to enable the support leg to fall and mutually abut against the ground, so that the support frame 10 is fixed on the ground through the rollover prevention assembly 20, rollover prevention is achieved, and shaking and movement in the operation process can be avoided. After the cat ladder is firmly fixed on the ground, a worker can climb up a preset height position by means of the pedal 11 to perform related operations, so that safety is improved, and the cat ladder can be flexibly used according to actual requirements.

Referring to fig. 1-3, in one embodiment, the number of rollover prevention assemblies 20 is at least two. Thus, when the at least two rollover prevention assemblies 20 are synchronously abutted and fixed with the ground, the ladder stand can be firmly fixed on the ground.

Referring to fig. 1 to 3, in one embodiment, a plurality of pedals 11 are disposed on a front surface 13 of a bracket 10, and at least one rollover prevention assembly 20 is disposed on each of opposite side surfaces 14 of the bracket 10.

Specifically, the front surface 13 of the stand 10 is provided as a slope disposed at an acute angle to the bottom surface of the stand 10, which facilitates a worker to climb up the top of the stand 10 along the pedal 11.

Referring to fig. 1 to 3, in one embodiment, at least two rollover prevention assemblies 20 are respectively disposed on two opposite sides 14 of the bracket 10, and the rollover prevention assemblies 20 on one side 14 of the bracket 10 and the rollover prevention assemblies 20 on the other side 14 are located correspondingly.

Referring to fig. 2, 4 and 5, fig. 4 shows a schematic cross-sectional structure of fig. 3 at B-B, and fig. 5 shows an enlarged schematic cross-sectional structure of fig. 4 at C. In one embodiment, the rollover prevention assembly 20 further includes a locking assembly 23 for locking and securing the support bar 21 to the bracket 10. Thus, under the locking and fixing action of the locking component 23, the supporting rod 21 is fixed on the bracket 10, so that the ladder stand can be further firmly fixed on the ground, and the safety is improved.

Specifically, when the crawling ladder is moved to a target position and needs to be fixed on the ground through the rollover prevention assembly 20 during operation, the locking assembly 23 is loosened, the supporting rod 21 is fixed on the support 10 through the locking assembly 23 after the supporting rod 21 is extended to a proper position, and in addition, the height position of the positioning supporting legs 22 is adjusted to enable the supporting legs to fall and mutually abut against the ground for fixation; when the worker finishes the maintenance operation by means of the ladder, the worker lifts and adjusts the position of the positioning support leg 22 again to separate the support leg from the ground, releases the locking assembly 23, withdraws the support rod 21 into the bracket 10, and then fixes the support rod 21 to the bracket 10 through the locking assembly 23, so that the ladder can be moved to the next destination without being affected by the support rod 21 and the support leg which extend out of the bracket 10.

Referring to fig. 2 and 5, in one embodiment, a sliding sleeve 15 is disposed at the bottom of the bracket 10, and a supporting rod 21 is slidably disposed in the sliding sleeve 15.

Alternatively, sliding sleeve 15 includes, but is not limited to, a rigid sleeve, such as a steel tube.

Further, the shape of the slide sleeve 15 and the outer shape of the support rod 21 are adapted to each other, so that the support rod 21 moves smoothly in the axial direction in the slide sleeve 15. Specifically, the cross-sectional shape of the sliding sleeve 15 includes, but is not limited to, a polygonal shape such as a square, a triangle, a pentagon, etc., or a circular shape, an oval shape, etc., and may be other regular shapes and irregular shapes.

Of course, as an alternative, the bottom of the bracket 10 is provided with a sliding member, the supporting bar 21 is provided with a sliding groove matched with the sliding member, and the sliding member is slidingly arranged in the sliding groove.

It should be noted that, the locking assembly 23 has a plurality of specific design forms, and can be used to lock and fix the support rod 21 on the support frame 10, including but not limited to using bolts, screws, pins, rivets, connecting ropes, clamping members, and other fasteners, and can be flexibly adjusted and set according to practical requirements.

Referring to fig. 2 and 5, in one embodiment, the locking assembly 23 includes a connecting rod 231, a wear pad 232, a resilient clamping pad 233, and a locking nut 234. The side wall of the sliding sleeve 15 is provided with a waist-shaped hole 151 extending along the axial direction, the connecting rod 231 is arranged in the waist-shaped hole 151 in a penetrating mode and connected with the supporting rod 21, the connecting rod 231 can move along the waist-shaped hole 151, threads matched with the locking nut 234 are arranged on the outer wall of the connecting rod 231, and the wear-resisting pad 232, the elastic clamping pad 233 and the locking nut 234 are sequentially sleeved on the connecting rod 231 and located outside the sliding sleeve 15. Thus, when the lock nut 234 is tightened, the lock nut 234 compresses the elastic clamping pad 233 and the wear pad 232, so that the support rod 21 is firmly connected to the sliding sleeve 15; when the lock nut 234 is released, the locking assembly 23 releases the sliding sleeve 15.

Specifically, the support rod 21 is provided with a through hole, two opposite side walls of the sliding sleeve 15 are respectively provided with a waist-shaped hole 151, the connecting rod 231 is arranged in the through hole in a penetrating mode, and two ends of the sliding sleeve 15 extend outwards through the two waist-shaped holes 151 respectively. The wear-resisting pad 232, the elastic clamping pad 233 and the locking nut 234 are arranged in two groups and are respectively arranged at two ends of the connecting rod 231.

It should be noted that, the positioning support leg 22 has more specific design forms, and can be flexibly adjusted and set according to actual requirements only by lifting and adjusting the height position.

Referring to fig. 5 and 6, fig. 6 shows a schematic cross-sectional view of fig. 5 at D-D. In one embodiment, the top end of the positioning leg 22 is provided with a screw 221, the end of the supporting rod 21 is provided with a connecting part 211, the connecting part 211 is provided with a screw hole corresponding to the screw 221, and the screw 221 is penetrated in the screw hole. Thus, when the positioning support leg 22 is rotated, the height of the skirting board 222 can be adjusted accordingly, so that the bottom end of the positioning support leg 22 can be closely attached to or separated from the ground.

Referring to fig. 5 and 6, in one embodiment, the end of the supporting rod 21 is connected with a square tube beam 212, the connecting portion 211 is fixedly connected to the inside of the square tube beam 212, the square tube beam 212 is provided with a avoiding hole corresponding to a screw hole of the connecting portion 211, and the screw 221 extends into the screw hole through the avoiding hole.

Referring to fig. 4 to 6, in one embodiment, the bottom end of the positioning leg 22 is provided with a baseboard 222. Optionally, the baseboard 222 includes, but is not limited to, an elastic plate for shock absorption, and may also be a hard plate, such as a metal plate, which is strong in stability and not easy to deform under stress.

In another embodiment, the ladder further includes a controller (not shown), and the rollover prevention assembly 20 further includes a pushing mechanism and a lifting mechanism (not shown). The pushing mechanism and the lifting mechanism are respectively and electrically connected with the controller. A pushing mechanism is connected to the stand 10 for driving the support rod 21 to extend to the outside of the stand 10 or retract into the stand 10. The lifting mechanism is connected to the supporting rod 21, and is also connected to the positioning support leg 22 for driving the positioning support leg 22 to move up and down. Therefore, the supporting rod 21 does not need to be manually driven to extend and retract outwards, the height position of the positioning support leg 22 does not need to be manually driven to be adjusted, the height position is adjusted by driving the positioning support leg 22 to move up and down through the lifting mechanism under the control of the controller, the position is adjusted by driving the supporting rod 21 to move through the pushing mechanism, the degree of automation is high, and manpower and material resources are reduced.

In some embodiments, the controller includes, but is not limited to, a sound sensor, which can sense sound information and control the pushing mechanism and the lifting mechanism to work correspondingly. The controller can also be mutually and electrically connected with electronic equipment such as a mobile phone, a computer, a tablet and the like, and can correspondingly control the pushing mechanism and the lifting mechanism to work according to the control instruction by inputting the control instruction on the electronic equipment. The controller may also be disposed on the stand 10 and provided with a touch screen, through which related control instructions are input, and any one of the rollover prevention assemblies 20 can be correspondingly controlled to act according to the control instructions.

Referring to fig. 1, in one embodiment, the ladder further includes a railing 30 disposed on the bracket 10. The top of the stand 10 is provided with a carrier plate 16. The guard rail 30 includes a first guard rail 3130 disposed on opposite sides of the step 11, and a second guard rail 3230 disposed on the carrier plate 16, the second guard rail 3230 being connected to the first guard rail 3130. One side of the carrier plate corresponds to the position of the pedal 11, and the other sides of the carrier plate are surrounded by the second guard rail 3230. Thus, the guard rail 30 plays a role in protection when workers climb the ladder and stand on the carrier plate, and the safety performance can be greatly improved.

Referring to fig. 1, in one embodiment, the bottom of the stand 10 is provided with a bottom plate 17. The plurality of pedals 11 are arranged between the bottom plate 17 and the carrier plate 16. The bottom plate 17 and the bearing plate 16 respectively comprise, but are not limited to, anti-skid plates, and the surfaces of the anti-skid plates comprise, but are not limited to, anti-skid structures such as patterns, convex points, concave parts and the like, so that a good anti-skid effect is achieved. The patterns can be flexibly adjusted and set according to actual requirements, and are not limited herein.

In one embodiment, the number of rollers 12 includes, but is not limited to, three, four, five, six, or other numbers. In this embodiment, the rollers 12 are, for example, four, and are respectively disposed at four corners of the bottom of the bracket 10.

Alternatively, the roller 12 includes, but is not limited to, a castor, or any other type of wheel.

It should be noted that the "pedal 11, sliding sleeve 15, bearing plate 16, and bottom plate 17" may be "a part of the bracket 10", that is, "pedal 11, sliding sleeve 15, bearing plate 16, and bottom plate 17" are manufactured by integral molding with "other parts of the bracket 10"; or a separate component which is separable from the rest of the bracket 10, namely the pedal 11, the sliding sleeve 15, the bearing plate 16 and the bottom plate 17 can be manufactured independently and then combined with the rest of the bracket 10 into a whole.

It should be noted that, the "connection portions 211 and Fang Guanliang 212" may be "a portion of the support rod 21", that is, "the connection portions 211 and Fang Guanliang" and "other portions of the support rod 21" are integrally formed; the connecting part 211 and the square tube beam 212 can be manufactured independently and then combined with the other parts of the supporting rod 21 into a whole.

It should be noted that, the "screw 221 and the baseboard 222" may be "a part of the positioning leg 22", that is, the "screw 221 and the baseboard 222" are integrally manufactured with "other parts of the positioning leg 22"; or a separate component which is separable from the other parts of the positioning leg 22, namely, the screw 221 and the baseboard 222 can be manufactured independently and then combined with the other parts of the positioning leg 22 into a whole.

Note that, the "second guard rail 3230" may be a part of the "first guard rail 3130", that is, the "second guard rail 3230" is integrally manufactured with the "other part of the first guard rail 3130"; it is also possible that a separate member is separable from the other part of the first guard rail 3130, i.e. "second guard rail 3230" may be manufactured separately and then combined with the other part of the first guard rail 3130 into one body.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples only represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the claims. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.

In the description of the present application, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," etc. indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be configured and operated in a particular orientation, and therefore should not be construed as limiting the present application.

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

In this application, unless specifically stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

In this application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" 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 are used herein for illustrative purposes only and are not meant to be the only embodiment.

Claims

1. A crawling ladder, characterized in that it comprises:

2. The ladder of claim 1, wherein the number of rollover prevention assemblies is at least two.

3. The ladder of claim 2, wherein a plurality of the pedals are disposed on a front surface of the bracket, and opposite sides of the bracket are each provided with at least one of the rollover prevention assemblies.

4. The ladder of claim 3, wherein at least two of the rollover prevention assemblies are respectively disposed on opposite sides of the bracket, and the rollover prevention assemblies on one side of the bracket correspond to the rollover prevention assemblies on the other side.

5. The ladder of claim 1, wherein the rollover prevention assembly further comprises a locking assembly for locking the support bar to the bracket.

6. The ladder of claim 5, wherein a sliding sleeve is arranged at the bottom of the bracket, and the support rod is slidably arranged in the sliding sleeve in a penetrating manner; and/or the bottom of the bracket is provided with a sliding part, the supporting rod is provided with a sliding groove matched with the sliding part, and the sliding part is arranged in the sliding groove.

7. The ladder of claim 6, wherein the locking assembly comprises a connecting rod, a wear pad, a resilient clip pad, and a locking nut; the side wall of sliding sleeve is provided with waist type hole along the axial direction extension, the connecting rod wears to locate in the waist type hole and with the bracing piece links to each other, just the connecting rod can be followed waist type hole activity, be equipped with on the outer wall of connecting rod with lock nut suited screw thread, wear pad elasticity card pad with lock nut overlaps in proper order establish connect in on the connecting rod, and be located the outside of sliding sleeve.

8. The ladder stand of claim 1, wherein the top end of the positioning support leg is provided with a screw, the end of the support rod is provided with a connecting part, the connecting part is provided with a screw hole corresponding to the screw, and the screw is arranged in the screw hole in a penetrating way; the bottom of location stabilizer blade is equipped with the baseboard.

9. The ladder of claim 1, further comprising a controller, the rollover prevention assembly further comprising a pushing mechanism and a lifting mechanism; the pushing mechanism and the lifting mechanism are respectively and electrically connected with the controller; the pushing mechanism is connected to the bracket and used for driving the supporting rod to extend out of the bracket or retract into the bracket; the lifting mechanism is connected to the supporting rod and is further connected with the positioning support leg and used for driving the positioning support leg to move up and down.

10. The ladder of any one of claims 1 to 9, further comprising a guard rail disposed on the bracket; the top of the bracket is provided with a bearing plate, the guardrail comprises a first protective fence arranged on two opposite sides of the pedal and a second protective fence arranged on the bearing plate, and the second protective fence is connected with the first protective fence; one side of the carrier plate corresponds to the position of the pedal, and the other sides of the carrier plate are surrounded by the second guard rail.