CN112407058A

CN112407058A - Anti-pinch B column of automobile

Info

Publication number: CN112407058A
Application number: CN202011442051.1A
Authority: CN
Inventors: 李永建; 李水兰; 李宇钢
Original assignee: Hangzhou Fuyang Xinyuan New Energy Co Ltd
Current assignee: Hangzhou Fuyang Xinyuan New Energy Co Ltd
Priority date: 2020-03-30
Filing date: 2020-03-30
Publication date: 2021-02-26
Also published as: CN111301531A; CN112407059A; CN111301531B

Abstract

The invention belongs to the field of hand clamping prevention of automobile doors, and particularly relates to a hand clamping prevention B column of an automobile, which comprises a B column, an arc plate A, a spring A, a main steel wire, an arc plate B, a spring B, a limiting block and a spring C, wherein the arc plate B matched with a front door leaf slides in an arc chute C on the B column around a vertical arc center axis of the arc chute C, and two springs B for resetting the arc plate B are symmetrically arranged on the arc plate B in the vertical direction from top to bottom; when current door leaf was opened, along with the oppression of preceding door leaf relieving to arc board A, arc board B is under the spring B effect of two energy storage states along with the opening of preceding door leaf and partial roll-off spout C gradually, and the part of slide-off spout C forms the blocking to getting into preceding door within range when propping up the right B post to the hand of the people who gets on the bus from the back door on the arc board B to avoid the hand of the people who gets on the bus from the back door to be closed in advance because of preceding door leaf and is hindered by the clamp at last car in-process.

Description

Anti-pinch B column of automobile

Technical Field

The invention belongs to the field of hand clamping prevention of automobile doors, and particularly relates to a hand clamping prevention B pillar of an automobile.

Background

The conventional slide-rail type door has a disadvantage that the conventional pivot type door occupies a large space, and has a disadvantage that when a person getting on from the rear door gets on the vehicle, a hand supporting the B-pillar may extend into the range of the front door, so that the hand of the person getting on from the rear door is pinched by the front door which is closed in advance before the hand is completely pulled away from the B-pillar. In order to effectively prevent hands of a person getting on from a rear door from being pinched by a front door, it is necessary to design a B-pillar for preventing hands from being pinched.

The invention designs a hand-clamping prevention B column of an automobile, which solves the problems.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention discloses a hand-clamping-preventing B column of an automobile, which is realized by adopting the following technical scheme.

In the description of the present invention, it should be noted that the terms "inside", "outside", "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that the products of the present invention conventionally use, which are merely for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, or be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.

The utility model provides a prevent tong B post of car which characterized in that: the sliding type front door leaf spring comprises a B column, an arc plate A, a spring A, a main steel wire, an arc plate B, a spring B, a limiting block and a spring C, wherein the arc plate B matched with a front door leaf slides in an arc chute C on the B column around the vertical arc center axis of the arc chute C; two sliding chutes E communicated with the sliding chutes C in the column B respectively slide limiting blocks B along the radial direction of the arc plate B, and the two limiting blocks B are respectively matched with two limiting grooves which are vertically and symmetrically distributed on the arc plate B in the vertical direction; and each limiting block B is provided with a spring C for resetting the limiting block B in a nested manner.

An arc-shaped sliding chute A is arranged on the side surface of the front door leaf hinged in the front door, and an arc plate A matched with the side surface of the front door leaf is arranged in the sliding chute A around the vertical arc center axis of the sliding chute A; and a spring A for resetting the arc plate A is arranged on the arc plate A.

When the front door leaf is closed, the arc plate A pressed by the side surface of the front door leaf and entering the sliding groove A drives the two limiting blocks B to remove the limiting on the arc plate B by pulling the main steel wire embedded in the vehicle body, the arc plate B is recycled into the sliding groove C under the closing pressing of the front door leaf, and the spring B is further stretched to store energy; along with the opening of the front door leaf, the arc plate A partially slides out of the sliding groove A under the action of the spring A in the energy storage state and gradually releases the pulling of the main steel wire, and meanwhile, the arc plate B partially slides out of the sliding groove C under the action of the two springs B in the energy storage state so as to prevent the hands of a person getting on the vehicle from being pinched by the closed front door leaf in a mode that the hands of the person getting on the vehicle from the rear door enter the range of the front door when supporting the B column.

As a further improvement of the technology, a slide block A is arranged on the cambered surface of the arc plate A, and the slide block A slides in an arc-shaped sliding groove B on the inner wall of the sliding groove A; the spring A is positioned in the sliding groove B; one end of the spring A is connected with the sliding block A, and the other end of the spring A is connected with the inner wall of the sliding chute B; two sliding blocks B are vertically and symmetrically arranged on the arc surface of the arc plate B in the vertical direction, and respectively slide in two arc sliding grooves D on the inner wall of the sliding groove C; the two springs B are respectively positioned in the two sliding grooves D; one end of the spring B is connected with the inner wall of the corresponding sliding groove D, and the other end of the spring B is connected with the sliding block B in the corresponding sliding groove D. The slide block A effectively plays an auxiliary guiding role in the sliding of the arc plate A in the sliding chute A, and the slide block B effectively plays an auxiliary guiding role in the sliding of the arc plate B in the sliding chute C.

As a further improvement of the technology, two limiting blocks A for limiting the arc plate A to slide out of the sliding groove A are symmetrically arranged on the arc plate A, and the two limiting blocks A are matched with the inner wall of the sliding groove A.

As a further improvement of the technology, a sealing groove A is arranged at the notch of the chute A, and a sealing ring A matched with the arc plate A is arranged in the sealing groove A; and a groove opening of the sliding groove C is provided with a sealing groove B, and a sealing ring B matched with the arc plate B is arranged in the sealing groove B.

As a further improvement of the technology, the inner wall of each sliding chute E is provided with a ring groove, and the two springs C are respectively positioned in the two ring grooves; one end of the spring C is connected with a pressure spring plate arranged on the corresponding limiting block B, and the other end of the spring C is connected with the inner wall of the corresponding ring groove.

As a further improvement of the technology, a through slide hole is arranged between the upper end surface and the lower end surface of the arc plate A; one end of the main steel wire penetrates through the sliding hole to be connected with the inner wall of the sliding chute A, and the other end of the main steel wire penetrates through a containing groove in the vehicle body to be connected with branch steel wires on the two limiting blocks B; the corners of total steel wire and branch steel wire are all cooperated with the fixed pulley that prevents mutual friction between the corners of total steel wire and branch steel wire and the holding tank.

Compared with the traditional automobile B column, the arc plate A drives the two limiting blocks B to relieve the limitation on the arc plate B through the interaction with the front door leaf in the closing motion, and then the arc plate B meets the front door leaf in the closing motion and is gradually recovered into the sliding groove C under the pressure of the front door leaf; when current door leaf was opened, along with the oppression of preceding door leaf relieving to arc board A, arc board B is under the spring B effect of two energy storage states along with the opening of preceding door leaf and partial roll-off spout C gradually, and the part of slide-off spout C forms the blocking to getting into preceding door within range when propping up the right B post to the hand of the people who gets on the bus from the back door on the arc board B to avoid the hand of the people who gets on the bus from the back door to be closed in advance because of preceding door leaf and is hindered by the clamp at last car in-process. When the human hand is blocked by the anti-pinch plate which swings out the B column, the human hand supporting the B column retracts subconsciously and cannot enter the range of the front door, so that the effective anti-pinch warning effect is exerted to a certain extent.

In addition, the structural characteristics of the arc plate B ensure that the B column has smaller thickness, so that the volume of the B column is effectively reduced while the B column is prevented from clamping hands, and the manufacturing cost of the vehicle is reduced. The invention has simple structure and better use effect.

Drawings

Fig. 1 is an overall schematic view of an automobile.

Fig. 2 is a schematic cross-sectional view of the arc plate a, the front door fan and the arc plate B.

Fig. 3 is a schematic cross-sectional view of the arc plate a and the front door fan.

Fig. 4 is a cross-sectional view of the arc plate B and the B-pillar.

Fig. 5 is a schematic cross-sectional view of the limiting block B, B pillar and the arc plate B.

Figure 6 is a schematic view of arc plate a.

Figure 7 is a schematic view of arc plate B.

FIG. 8 is a schematic cross-sectional view of the car body, the main steel wire and the arc plate A.

FIG. 9 is a schematic cross-sectional view of the slot A, the slot B and the seal groove A.

FIG. 10 is a schematic cross-sectional view of the slot C, the slot D and the slot B.

FIG. 11 is a cross-sectional view of the sliding groove C, the sliding groove E, the ring groove and the accommodating groove.

Fig. 12 is a schematic cross-sectional view of the relative positions of the sliding groove a and the accommodating groove.

Fig. 13 is a schematic cross-sectional view of the fit between the stopper a and the inner wall of the sliding groove a.

Number designation in the figures: 1. a vehicle body; 2. a front door; 3. a rear door; 4. a column B; 5. a front door leaf; 6. a chute A; 7. a chute B; 8. a chute C; 9. a chute D; 10. a sealing groove B; 11. a chute E; 12. a ring groove; 13. accommodating grooves; 14. an arc plate A; 15. a slide hole; 16. a slide block A; 17. a spring A; 18. a sealing ring A; 19. a total steel wire; 21. an arc plate B; 22. a slide block B; 23. a spring B; 24. a seal ring B; 25. a limiting groove; 26. a limiting block B; 27. a spring C; 28. a compression spring plate; 29. supporting steel wires; 30. a fixed pulley; 31. a rear door leaf; 32. a sealing groove A; 33. and a limiting block A.

Detailed Description

The drawings are schematic illustrations of the implementation of the present invention to facilitate understanding of the principles of structural operation. The specific product structure and the proportional size are determined according to the use environment and the conventional technology.

As shown in fig. 1, 2 and 5, the sliding door comprises a B-pillar 4, an arc plate a14, a spring a17, a main steel wire 19, an arc plate B21, a spring B23, a limiting block and a spring C27, wherein as shown in fig. 4, 7 and 10, an arc plate B21 matched with the front door leaf 5 slides in an arc chute C8 on the B-pillar 4 around a vertical arc center axis of the arc chute, and two springs B23 for resetting the arc plate B21 are vertically and symmetrically arranged on the arc plate B21 in an up-down symmetrical manner; as shown in fig. 5, 7 and 11, two slide grooves E11 in the B column 4, which are communicated with the slide groove C8, respectively slide a limiting block B26 along the radial direction of the arc plate B21, and the two limiting blocks B26 are respectively matched with two limiting grooves 25 vertically and symmetrically distributed on the arc plate B21; each limiting block B26 is nested with a spring C27 for resetting the limiting block B.

As shown in fig. 3 and 9, an arc chute a6 is formed in the side surface of the front door 2 hinged to the front door leaf 5, and an arc plate a14 matched with the side surface of the front door leaf 5 is arranged in the chute a6 around the vertical arc center axis thereof; as shown in fig. 3 and 6, a spring a17 for returning the arc plate a14 is mounted thereon.

As shown in fig. 2, 5 and 8, when the front door leaf 5 is closed, the arc plate a which enters the chute a6 under the pressure of the side surface of the front door leaf 5 drives two limiting blocks B to remove the limiting on the arc plate B21 by pulling the main steel wire 19 embedded in the vehicle body 1, the arc plate B21 is recovered into the chute C8 under the closing pressure of the front door 2, and the spring B23 is further stretched to store energy; as the front door leaf 5 is opened, the arc plate a14 slides out of the slide groove a6 partially under the action of the spring a17 in the energy storage state and gradually releases the pulling of the main steel wire 19, while the arc plate B21 slides out of the slide groove C8 partially under the action of the two springs B23 in the energy storage state to prevent the hands of the person getting on from the rear door 3 from being pinched by the closing front door leaf 5 by blocking the hands of the person getting on the rear door 2 from entering the range of the front door 2 when holding up the B pillar 4.

As shown in fig. 3, 6 and 9, a slide block a16 is mounted on the arc surface of the arc plate a14, and the slide block a16 slides in an arc slide groove B7 on the inner wall of the slide groove a 6; the spring A17 is positioned in the sliding groove B7; one end of the spring A17 is connected with the sliding block A16, and the other end of the spring A17 is connected with the inner wall of the sliding groove B7; as shown in fig. 4, 7 and 10, two sliding blocks B22 are vertically and symmetrically installed on the arc surface of the arc plate B21, and the two sliding blocks B22 respectively slide in two arc-shaped sliding grooves D9 on the inner wall of the sliding groove C8; the two springs B23 are respectively positioned in the two chutes D9; one end of the spring B23 is connected with the inner wall of the corresponding slide groove D9, and the other end is connected with the slide block B22 in the corresponding slide groove D9. The sliding block A16 effectively plays an auxiliary guiding role in the sliding of the arc plate A14 in the sliding groove A6, and the sliding block B22 effectively plays an auxiliary guiding role in the sliding of the arc plate B21 in the sliding groove C8.

As shown in fig. 3, 6 and 13, two limit blocks a33 for limiting the arc plate a14 to slide out of the sliding groove a6 are symmetrically installed on the arc plate a14, and the two limit blocks a33 are matched with the inner wall of the sliding groove a 6.

As shown in fig. 3 and 9, the notch of the chute a6 has a sealing groove a32, and a sealing ring a18 fitted with the arc plate a14 is installed in the sealing groove a 32; as shown in fig. 4 and 10, the notch of the chute C8 has a sealing groove B10, and a sealing ring B24 which is matched with the arc plate B21 is installed in the sealing groove B10.

As shown in fig. 5 and 11, each of the sliding grooves E11 has a ring groove 12 on its inner wall, and two springs C27 are respectively located in the two ring grooves 12; one end of the spring C27 is connected with the pressure spring plate 28 arranged on the corresponding limit block B26, and the other end is connected with the inner wall of the corresponding ring groove 12.

As shown in fig. 5, 8 and 12, the arc plate a14 has a through slide hole 15 between its upper and lower end faces; one end of the main steel wire 19 penetrates through the sliding hole 15 to be connected with the inner wall of the sliding groove A6, and the other end of the main steel wire penetrates through the accommodating groove 13 in the vehicle body 1 to be connected with the branch steel wires 29 on the two limiting blocks B26; the corners of the main and

branch wires

19 and 29 are fitted with fixed pulleys 30 that prevent the main and

branch wires

19 and 29 from rubbing against each other at the corners of the accommodating groove 13.

The present invention is applicable to a vehicle having a slide rail type rear door leaf 31.

The spring C27 in the present invention is always in compression, and the springs A17 and B23 are always in tension.

The arc a14 of the present invention interacts with the front door leaf 5 first during the closing of the front door leaf 5.

The working process of the invention is as follows: the invention takes the complete closing of the front door 2 as the initial state, at this time, the arc plate A14 is pressed by the side surface of the front door leaf 5 to completely enter the chute A6, and the arc plate B21 is pressed by the front door leaf 5 to be completely positioned in the chute C8. The spring A17 is in a tension energy storage state, and the two springs B23 are in a tension energy storage state. The main steel wire 19 and the branch steel wires 29 are in a tensioned state. The ends of the two limit blocks B26, which are matched with the limit grooves 25 on the arc plate B21, are positioned in the slide grooves E11 and do not limit the arc plate B21. The spring C27 is in a compressed energy storage state.

When the front door 5 is gradually opened, the front door 5 gradually releases the pressing of the arc plate a14 and the arc plate B21. The arc plate A14 slides out of the sliding groove A6 gradually under the action of the spring A17, at the moment, the movement of the arc plate A14 releases the tightening state of the main steel wire 19 gradually, and the main steel wire 19 releases the pulling of the two limit blocks B26 through the two branch steel wires 29. The two limit blocks B26 are respectively and simultaneously gradually close to the cambered surface of the cambered plate B21 under the action of the corresponding springs C27. At the same time, the arc plate B21 gradually slides out of the chute C8 under the action of the two springs B23.

When the two limit blocks B26 reach the arc surface of the arc plate B21, the two limit blocks B26 stop moving and generate relative friction with the arc surface of the arc plate B21, the two limit blocks B26 gradually approach the two limit grooves 25 on the moving arc plate B21, and the total steel wire 19 starts to be in a loose state along with the continuous movement of the arc plate A14.

When the front door leaf 5 is opened at a certain angle, the arc plate B21 is separated from the front door leaf 5, and at this time, the two limit grooves 25 on the arc plate B21 just meet the two limit blocks B26. The two limit blocks B26 are respectively embedded into the corresponding limit grooves 25 under the action of the corresponding springs C27 and limit the arc plates B21 at the same time. At this time, the arc plate B21 just separates from the front door 5 and stops moving, and the arc plate a14 is still pressed by the side of the front door 5.

With the continuous opening of the front door leaf 5, the arc plate a14 continues to move outwards the sliding groove a6, the main steel wire 19 continues to be released, and the two limit blocks B26 continue to be further embedded into the corresponding limit grooves 25 under the action of the corresponding springs C27. When the two limit blocks B26 stop moving at the same time under the stop of the corresponding compression spring plate 28, the opening angle of the front door fan 5 is about 30 degrees, and the arc plate A14 stops moving under the interaction of the two limit blocks A33 and the inner wall of the sliding chute A6. Thereafter, as the front door leaf 5 continues to open to its maximum angle, the arc a14 and the arc B21 no longer move as the front door leaf 5 opens. The arc plate B21 of the sliding chute C8 protrudes out of the outer side surface of the B column 4 to form a barrier with a certain height between the front door 2 and the rear door 3, when the hands of a person getting on the vehicle from the rear door are supported on the B column 4, the hands of the person getting on the vehicle are blocked by the arc plate B21 protruding out of the outer side surface of the B column 4 and cannot enter the range of the front door 2, so that the hands of the person getting on the vehicle are always positioned outside the range of the front door 2 in the process of getting on the vehicle, and the hands supporting the B column 4 are prevented from being pinched due to the early closing of the front door leaf 5.

When the front door leaf 5 performs closing movement, when the angle between the front door leaf 5 and the side face of the vehicle body 1 reaches about 30 degrees, the exposed end of the arc plate A14 contacts with the side face of the front door leaf 5 and slides gradually into the sliding groove A6 under the action of the continuously closed front door leaf 5, the arc plate A14 drives the spring A17 to be stretched and stored energy again through the sliding block A16, and the side faces of the two limiting blocks A33 start to be separated from the inner side wall of the sliding groove A6. Along with the movement of the arc plate A14 to the sliding groove A6, the main steel wire 19 slides in the sliding hole 15 on the arc plate A14 relative to the arc plate A14, the arc plate A14 restarts to pull the two limit blocks B26 to gradually separate from the two limit grooves 25 on the arc plate B21 by further tightening the main steel wire 19 and the two branch steel wires 29, so that the two limit blocks B26 gradually release the limit on the arc plate B21, and the two springs C27 are compressed again to store energy.

As the front door leaf 5 closes, the arc a14 continues to be forced into the chute a6 and the front door leaf 5 gradually approaches the exposed end of the arc B21. When the front door leaf 5 meets the arc plate B21, the arc plate a14 pulls the two stopper blocks B26 completely out of the two stopper grooves 25 on the arc plate B21 through the main steel wire 19 and the branch steel wire 29 gradually tightened by the arc plate a, so that the two stopper blocks B26 simultaneously release the stopper of the arc plate B21. The arc plate B21 starts to move towards the inside of the sliding groove C8 under the action of the continuously closed front door leaf 5, the arc plate A14 continuously contracts towards the inside of the sliding groove A6 under the pressure of the front door leaf 5, the two springs B23 are stretched again to store energy, and the arc plate A14 drives the two limit blocks B26 to continuously contract towards the inside of the corresponding sliding groove E11 through the continuously tightened main steel wire 19 and the support steel wire 29.

When the front door leaf 5 is completely closed, the arc a14 and the arc B21 are completely restored to the original state.

In conclusion, the beneficial effects of the invention are as follows: the arc plate A14 drives the two limit blocks B26 to release the limit of the arc plate B21 through the interaction with the front door leaf 5 in the closing motion, and then the arc plate B21 meets the front door leaf 5 in the closing motion and is gradually recovered into the chute C8 under the pressure of the front door leaf 5; when the front door leaf 5 is opened, along with the release of the front door leaf 5 to the oppression of the arc plate A14, the arc plate B21 is under the effect of the spring B23 in two energy storage states and is gradually partly slipped out of the sliding groove C8 along with the opening of the front door leaf 5, and the part of the arc plate B21 slipped out of the sliding groove C8 forms a barrier in the range of the front door 2 when the hand of a person getting on the vehicle from the rear door 3 enters the B column 4, so that the situation that the hand of the person getting on the vehicle from the rear door 3 is pinched due to the fact that the front door leaf 5 is closed in advance in the process of getting on. When the staff receives the anti-pinch plate who puts out B post 4 and blocks, prop the hand of the people who supports B post 4 and contract back subconsciously and can not get into the within range of preceding door 2 to exert effectual anti-pinch warning effect to a certain extent.

In addition, the structural characteristics of the arc plate B21 in the invention ensure that the B column 4 has smaller thickness, so that the volume of the B column 4 is effectively reduced while the B column 4 is prevented from clamping hands, and the manufacturing cost of the vehicle is reduced.

Claims

1. The utility model provides a prevent tong B post of car which characterized in that: the sliding type front door leaf spring comprises a B column, an arc plate A, a spring A, a main steel wire, an arc plate B, a spring B, a limiting block and a spring C, wherein the arc plate B matched with a front door leaf slides in an arc chute C on the B column around the vertical arc center axis of the arc chute C; two sliding chutes E communicated with the sliding chutes C in the column B respectively slide limiting blocks B along the radial direction of the arc plate B, and the two limiting blocks B are respectively matched with two limiting grooves which are vertically and symmetrically distributed on the arc plate B in the vertical direction; each limiting block B is provided with a spring C for resetting the limiting block B in a nested manner;

an arc-shaped sliding chute A is arranged on the side surface of the front door leaf hinged in the front door, and an arc plate A matched with the side surface of the front door leaf is arranged in the sliding chute A around the vertical arc center axis of the sliding chute A; the arc plate A is provided with a spring A for resetting the arc plate A;

when the front door leaf is closed, the arc plate A pressed by the side surface of the front door leaf and entering the sliding groove A drives the two limiting blocks B to remove the limiting on the arc plate B by pulling the main steel wire embedded in the vehicle body, the arc plate B is recycled into the sliding groove C under the closing pressing of the front door leaf, and the spring B is further stretched to store energy; along with the opening of the front door leaf, the arc plate A partially slides out of the sliding groove A under the action of the spring A in the energy storage state and gradually releases the pulling of the main steel wire, and simultaneously the arc plate B partially slides out of the sliding groove C under the action of the two springs B in the energy storage state so as to prevent the hands of a person getting on the vehicle from being pinched and damaged by the closed front door leaf in a mode of blocking the hands of the person getting on the vehicle from the rear door from entering the range of the front door leaf when propping up the B column;

the arc plate A is symmetrically provided with two limiting blocks A for limiting the arc plate A to slide out of the chute A, and the two limiting blocks A are matched with the inner wall of the chute A;

a sealing groove A is formed in the notch of the sliding groove A, and a sealing ring A matched with the arc plate A is installed in the sealing groove A; a sealing groove B is formed in the notch of the sliding groove C, and a sealing ring B matched with the arc plate B is installed in the sealing groove B;

the inner wall of each sliding chute E is provided with a ring groove, and the two springs C are respectively positioned in the two ring grooves; one end of the spring C is connected with a pressure spring plate arranged on the corresponding limiting block B, and the other end of the spring C is connected with the inner wall of the corresponding ring groove.

2. The anti-pinch B column of the automobile as claimed in claim 1, characterized in that: a slide block A is arranged on the cambered surface of the arc plate A and slides in an arc sliding groove B on the inner wall of the sliding groove A; the spring A is positioned in the sliding groove B; one end of the spring A is connected with the sliding block A, and the other end of the spring A is connected with the inner wall of the sliding chute B; two sliding blocks B are vertically and symmetrically arranged on the arc surface of the arc plate B in the vertical direction, and respectively slide in two arc sliding grooves D on the inner wall of the sliding groove C; the two springs B are respectively positioned in the two sliding grooves D; one end of the spring B is connected with the inner wall of the corresponding sliding groove D, and the other end of the spring B is connected with the sliding block B in the corresponding sliding groove D.

3. The anti-pinch B column of the automobile as claimed in claim 1, characterized in that: a through sliding hole is formed between the upper end surface and the lower end surface of the arc plate A; one end of the main steel wire penetrates through the sliding hole to be connected with the inner wall of the sliding chute A, and the other end of the main steel wire penetrates through a containing groove in the vehicle body to be connected with branch steel wires on the two limiting blocks B; the corners of total steel wire and branch steel wire are all cooperated with the fixed pulley that prevents mutual friction between the corners of total steel wire and branch steel wire and the holding tank.