CN108451253B

CN108451253B - City planning is with quick detach formula multilayer display device

Info

Publication number: CN108451253B
Application number: CN201810278696.2A
Authority: CN
Inventors: 高成全; 邱小亮; 刘申; 张俊博; 董勤良; 李梦迪
Original assignee: Henan University of Urban Construction
Current assignee: Hefei Longzhi Electromechanical Technology Co ltd
Priority date: 2018-03-30
Filing date: 2018-03-30
Publication date: 2020-02-18
Anticipated expiration: 2038-03-30
Also published as: CN108451253A

Abstract

The invention relates to a quick-release type multilayer display device for city planning, which effectively solves the problems that a display rack is inconvenient to disassemble and assemble and the display is not three-dimensional; the technical scheme for solving the problem is that the device comprises a flat plate, wherein a first rotating shaft which can slide left and right and can rotate is arranged on the flat plate, a plurality of supporting rods which are arranged up and down are arranged above the first rotating shaft, and a telescopic mechanism is arranged between each supporting rod and the first rotating shaft; the front end and the rear end of the supporting rod are provided with sleeves, the front sleeve and the rear sleeve are provided with detachable hollow cylinders, a second rotating shaft is arranged in each cylinder, a rotatable connecting rod is arranged on each cylinder, the front end and the rear end of each supporting rod are hinged with limiting rods, spring pieces are arranged between the limiting rods and the supporting rod, the inner edge surfaces of the sleeves are provided with annular grooves, the limiting rods can be arranged in the annular grooves, the inner edge surfaces of the sleeves are provided with first grooves, the supporting rods are provided with first pins, a first rope is arranged between the first pins and the limiting rods, the first pins are located on the outer sides of the limiting rods, and the first pins; the invention has the advantages of ingenious structure, strong practicability, novel conception and diversified display effect.

Description

City planning is with quick detach formula multilayer display device

Technical Field

The invention relates to the field of urban planning, in particular to a quick-release type multilayer display device for urban planning.

Background

In urban construction planning and display, a building sand table model is often used for visually reflecting planning schemes or combinations in the area so as to accurately express planning ideas and expected effects, but because the sand table model with a single plane can only display one idea and scheme, a planning designer cannot simultaneously display a plurality of ideas in the same sand table model, and if the planning area is large, the occupied area of the model is large, the planning details cannot be completely reflected, a viewer cannot accurately know the design ideas or ideas of the designer through the sand table model, particularly for multi-layer buildings, each layer has different design ideas, a three-dimensional visual feeling is difficult to present by adopting a traditional mode, and the traditional display mode is generally single and cannot be switched randomly, so that the display effect is influenced, lack of novelty and no visual impact.

Meanwhile, the display cabinets such as city planning display, commercial building layout display and building planning model sand table display in colleges and universities are generally fixedly installed integrated structures, the display cabinet with the integrated structure has the advantages of good display effect and stable structure, but the display cabinet with the structure has more defects, such as inconvenience in disassembly and movement, resource waste, large display table size and difficulty in moving, and the building planning teacher in colleges and universities cannot realize classroom field sand table teaching. Therefore, the existing display devices are increasingly unable to meet the urban development, and need to be improved.

Disclosure of Invention

In view of the above situation, in order to solve the problems in the prior art, the present invention aims to provide a quick-release multi-layer display device for city planning, which can effectively solve the problems that the display rack can not be folded at will and can not be disassembled and assembled, the carrying is inconvenient, and the display effect is not good.

The technical scheme for solving the problem is that the device comprises a flat plate, wherein two sliding blocks capable of moving left and right along the flat plate are respectively arranged on the front side and the rear side of the flat plate, the sliding blocks on the left side and the right side respectively correspond to each other front and back, a rotatable first rotating shaft is connected between the front sliding block and the rear sliding block on the same side, a plurality of supporting rods which are parallel to the first rotating shaft and are arranged up and down are arranged above the first rotating shaft, and telescopic mechanisms are connected between every two adjacent supporting rods and between the; the support rods are not rotatable, a rotatable sleeve is sleeved at each of the front end and the rear end of each support rod, the sleeves can move back and forth along the support rods, a hollow cylinder which is parallel to the support rods and is detachable is mounted on each of the front sleeve and the rear sleeve, a rotatable second rotating shaft penetrates through the cylinder, a torsion spring is arranged between each second rotating shaft and the cylinder, and a connecting rod capable of swinging back and forth is respectively arranged at each of the front end and the rear end of the cylinder;

the front end and the rear end of each supporting rod are hinged with a plurality of limiting rods, the inner ends of the limiting rods can swing left and right and can be arranged in the supporting rods, and spring pieces are arranged between the limiting rods and the supporting rods; the inner edge surface of the sleeve is provided with an annular groove, the sleeve moves inwards along the support rod to enable the limiting rod to be arranged in the annular groove, a plurality of first grooves penetrating through the front side surface and the rear side surface of the sleeve are uniformly distributed on the inner edge surface of the sleeve in the circumferential direction, a plurality of first pins which are distributed in the radial direction and can move in the radial direction of the support rod are arranged on the support rod, a first rope is connected between each first pin and the corresponding limiting rod, and the spring piece can enable the first pins to be arranged in the support rod through the limiting rod and the first ropes when being reset; first pin is located the foreign side of gag lever post, is equipped with reset spring on the first pin, moves inwards as the sleeve, can extrude the gag lever post and draw close to the axis of bracing piece, and first pin can be arranged in first recess simultaneously.

The multifunctional display device is ingenious in structure, strong in practicability, novel in conception, diversified in display effect, good in adjustability, convenient to disassemble and assemble, free of occupying space, and extremely convenient to carry and transport.

Drawings

Fig. 1 is a front view (expanded state) of the present invention.

Fig. 2 is a top view of the present invention.

Fig. 3 is a partially enlarged view of fig. 1.

Fig. 4 is a top view of the support rod and the cylinder.

Fig. 5 is a partially enlarged view of fig. 4.

Fig. 6 is a cross-sectional view taken along line a-a of fig. 5.

Fig. 7 is a cut-away view of the sleeve.

Fig. 8 is a diagram showing the relationship between the slider and the first rotating shaft.

Fig. 9 is a top view (folded state) of the present invention.

Detailed Description

The following describes in further detail embodiments of the present invention with reference to the accompanying drawings.

As shown in fig. 1 to 9, the invention comprises a flat plate 1, two slide blocks 2 capable of moving left and right along the flat plate 1 are respectively arranged on the front side and the rear side of the flat plate 1, the slide blocks 2 on the left side and the right side respectively correspond to each other front and rear sides, a rotatable first rotating shaft 3 is connected between the front slide block 2 and the rear slide block 2 on the same side, a plurality of support rods 4 parallel to the first rotating shaft 3 and arranged up and down are arranged above the first rotating shaft 3, and telescopic mechanisms are connected between the adjacent two support rods 4 and between the support rods 4 and the first rotating shaft 3; the support rods 4 are not rotatable, a rotatable sleeve 5 is sleeved at each of the front end and the rear end of each support rod 4, the sleeves 5 can move back and forth along the support rods 4, a hollow cylinder 6 which is parallel to the support rods 4 and is detachable is mounted on each of the front sleeve 5 and the rear sleeve 5, a rotatable second rotating shaft 7 penetrates through the cylinder 6, a torsion spring 8 is arranged between each second rotating shaft 7 and the cylinder 6, and a connecting rod 9 capable of swinging back and forth is respectively arranged at each of the front end and the rear end of the cylinder 6;

a plurality of limiting rods 10 are hinged to the front end and the rear end of each supporting rod 4, the inner ends of the limiting rods 10 can swing left and right and can be arranged in the supporting rods 4, and spring pieces 11 are arranged between the limiting rods 10 and the supporting rods 4; an annular groove 12 is formed in the inner edge surface of the sleeve 5, the sleeve 5 moves inwards along the support rod 4 to enable the limiting rod 10 to be arranged in the annular groove 12, a plurality of first grooves 13 penetrating through the front side surface and the rear side surface of the sleeve 5 are evenly distributed on the circumference of the inner edge surface of the sleeve 5, a plurality of first pins 14 which are distributed radially and can move radially along the support rod 4 are arranged on the support rod 4, a first rope 15 is connected between each first pin 14 and the corresponding limiting rod 10, and the first pins 14 are arranged in the support rod 4 when the spring piece 11 resets through the limiting rods 10 and the first ropes 15; the first pin 14 is located outside the stop lever 10, and the first pin 14 is provided with a return spring 16, so that when the sleeve 5 moves inwards, the sleeve will press the stop lever 10 to approach the axis of the support rod 4, and meanwhile, the first pin 14 will be placed in the first groove 13.

In order to facilitate the separation of the stop rods 10 from the annular groove 12, a second rope 17 is connected to the end of each stop rod 10, and the other ends of the second ropes 17 are connected to each other and disposed outside the support rod 4.

In order to enable the sliding block 2 to move left and right along the flat plate 1, a T-shaped groove is formed in the flat plate 1, a T-shaped block matched with the T-shaped groove is arranged at the lower end of the sliding block 2, the T-shaped block is arranged in the T-shaped groove and moves left and right along the T-shaped groove, a vertical set screw 18 is connected to the sliding block 2 in a threaded mode, and the lower end of the set screw 18 can be arranged in the T-shaped groove.

In order to facilitate the rotation and the positioning of the first rotating shaft 3 along the sliding block 2, a plurality of radial second grooves 19 are uniformly distributed on the first rotating shaft 3 positioned in the sliding block 2 in the circumferential direction, a plurality of first blind holes in one-to-one correspondence with the second grooves 19 are formed in the sliding block 2, second pins 20 capable of moving along the first blind holes are arranged in the first blind holes, a pressure spring is arranged between the second pins 20 and the first blind holes, and the second pins 20 can be arranged in the second grooves 19.

In order to realize fixing, the expansion bracket comprise a plurality of expansion units which are hinged with each other in the end, each expansion unit comprises a pair of connecting rods 21 with hinged middle parts, two fixing blocks 22 capable of sliding along the first rotating shaft 3 are sleeved on the first rotating shaft 3, the end parts of the connecting rods 21 are hinged on the fixing blocks 22, meanwhile, the cross section of the supporting rod 4 is square, and the inner edge surface of each fixing block 22 is also square.

In order to realize the detachable installation of the sleeve 5 and the cylinder 6, the outer edge surface of the sleeve 5 is provided with a convex block 23, the outer edge surface of the cylinder 6 is provided with a T-shaped groove matched with the convex block 23, and the convex block 23 can be arranged in the T-shaped groove and can move back and forth along the T-shaped groove.

In order to facilitate the first pin 14 to be placed in the first groove 13, a plurality of second radial blind holes are uniformly distributed on the inner edge surface of the support rod 4, the first pin 14 is placed in the second blind holes and can move along the second blind holes, and the return spring 16 is located between the first pin 14 and the bottoms of the second blind holes.

In order to shrink and display drawings, an opening is formed in the outer edge surface of the cylinder 6, one end of the connecting rod 9 is hinged to the cylinder 6, and hinged points of the connecting rod 9 and the cylinder 6 are located on the front side and the rear side of the opening respectively and have certain friction force.

Before use, the support rods 4 on the left side and the right side are in a contraction state under the action of the telescopic mechanisms, namely two fixing blocks 22 sleeved on each support rod 4 are respectively positioned at the front end and the rear end of each support rod 4, the distance between every two adjacent support rods 4 is in a smaller state through the connecting rods 21 which are hinged with each other, and meanwhile, the distance between the rotating shaft and the telescopic rods is smaller, so that the whole structure is more compact; first pivot 3 is in rotatable state about simultaneously, and locking screw has not locked yet, and two first pivots 3 rotate this moment about to a plurality of bracing pieces 4 and be in the horizontally state, constitute the bracing piece 4 tiling of the left and right sides on dull and stereotyped 1 effect. So that the height of the entire device is only about the thickness of two plates 1.

At this moment, the sleeve 5 is not sleeved at the end part of the supporting rod 4, meanwhile, the sleeve 5 and the cylinder 6 are clamped through the convex block 23, the sleeve 5 can move back and forth along the cylinder 6 and can be separated from the cylinder 5 and the cylinder 6, the sleeve 5 and the cylinder 6 are also in a separated state at this moment, drawings needing to be displayed are wound on a second rotating shaft 7 in the cylinder 6 in advance, the drawings can keep a state of being wound on the second rotating shaft 7 under the action of a torsion spring 8 sleeved on the second rotating shaft 7, the cylinder 6, the sleeve 5, the flat plate 1 and the supporting rod 4 are in a separated state, and then all parts and devices can be packaged well by using a box, so that the carrying is convenient and the transportation is convenient.

Furthermore, because the spring piece 11 is connected between the limiting rod 10 and the support rod 4, and the elastic force of the spring piece 11 is greater than that of the return spring 16, when the sleeve 5 is not sleeved on the support rod 4, the spring piece 11 can press the limiting rod 10 at this time, so that the limiting rods 10 are in an open state, and simultaneously, under the action of the first rope 15 connected between the limiting rod 10 and the first pin 14, the first pin 14 is placed in the second blind hole and does not extend out of the second blind hole, wherein the end part of the support rod 4 is provided with a central hole of an axis, so that the first rope 15 can be conveniently arranged, and the first rope 15 can penetrate through the central hole to connect the limiting rod 10 and the first pin 14.

When the display is needed, firstly, the flat plate 1 is horizontally placed on the ground, the flat plate 1 can be properly fixed according to needs, then the first rotating shaft 3 is rotated, the supporting rods 4 on the left side and the right side are driven by the telescopic mechanism to rotate together, the rotating angle is adjusted according to needs, and different display effects can be realized by rotating different angles and adjusting the sliding distance of the sliding block 2; in the rotating process of the first rotating shaft 3, the first rotating shaft 3 can rotate along the sliding block 2, at the moment, the second groove 19 is formed in the first rotating shaft 3, so that the second pin 20 can be clamped in the second groove 19 in the rotating process, the rotating shaft continues to rotate due to the fact that the force for rotating the first rotating shaft 3 is large, the second pin 20 can be separated from the second groove 19, and when the first rotating shaft 3 is not rotated, the second pin 20 can be clamped in the second groove 19, so that the position of the rotating shaft is fixed and does not rotate relative to the sliding block 2; meanwhile, after the distance between the sliding block 2 and the flat plate 1 is adjusted, the locking screw is rotated to enable the lower end face of the locking screw to be in contact with the flat plate 1, and the sliding block 2 cannot slide continuously at the moment, so that the sliding block 2 is positioned.

After the position of pivot has been fixed, upwards tensile bracing piece 4 this moment, perhaps tensile telescopic machanism makes the distance between bracing piece 4 and the bracing piece 4 adjusted greatly, the distance between bracing piece 4 and the first pivot 3 also can be adjusted bigger than great simultaneously, make whole device be in a higher position, because have certain frictional force between the connecting rod 21 of mutual articulated, certain frictional force has in the hinge point department promptly, consequently after the extension, whole device can keep the state after the extension, if the frictional force does not resist when the gravity of customer service bracing piece 4, can adopt supplementary connecting rod 9 to fix telescopic machanism, place telescopic machanism shrink.

After the position of the support rod 4 is adjusted, the front end and the rear end of the cylinder 6 are respectively clamped with a sleeve 5, and the raised blocks 23 on the sleeve 5 can slide in along the T-shaped grooves of the cylinder 6 because the raised blocks 23 are arranged on the outer edge surface of the sleeve 5 and the T-shaped grooves matched with the raised blocks 23 are arranged on the outer edge surface of the cylinder 6.

Then correspond the sleeve 5 and the bracing piece 4 at the front and back both ends of drum 6 to continue inwards slip sleeve 5, and make sleeve 5 not contact with gag lever post 10 simultaneously, because first pin 14 is arranged in the second blind hole this moment, consequently first pin 14 can not be arranged in the recess on sleeve 5 inner fringe face, continue rotatory sleeve 5 subsequently, because the cross section of bracing piece 4 and the inner fringe face of fixed block 22 are square this moment, therefore, bracing piece 4 can not rotate, and the front and back both ends of bracing piece 4 and sleeve 5 are to the part of contact, the cross section is circular, and bracing piece 4 and sleeve 5 are clearance fit, therefore sleeve 5 can rotate.

After the rotating sleeve 5 reaches a proper angle, the rotating sleeve 5 is stopped at the moment, the sleeve 5 continues to slide inwards, the limiting rod 10 can be extruded by the sleeve 5 at the moment, the limiting rod 10 moves towards the axis direction of the supporting rod 4, meanwhile, the first rope 15 can be loosened, the first pin 14 moves outwards under the action of the reset spring 16 and is clamped in the groove of the inner edge surface of the sleeve 5, the sleeve 5 cannot rotate, and the groove penetrates through the front side surface and the rear side surface of the sleeve 5, so that the first pin 14 can move back and forth along the groove, and the sleeve 5 can continue to move inwards along the supporting rod 4.

When the sleeve 5 continues to move inwards, the first pin 14 does not move at the moment, meanwhile, the limiting rod 10 is arranged in the annular groove 12 of the inner edge surface of the sleeve 5, when the limiting rod 10 is arranged in the annular groove 12, the limiting rod 10 can be clamped in the annular groove 12 under the action of the spring piece 11, the sleeve 5 cannot slide outwards, the rotating angle of the sleeve 5 is increased, and the front position and the rear position of the sleeve 5 are fixed.

After the sleeve 5 is fixed, the connecting rod 9 hinged on the outer edge surface of the cylinder 6 is pulled to be vertical to the cylinder 6, the drawing wound on the second rotating shaft 7 is pulled out of the cylinder 6, and the drawing is fixed on the connecting rod 9 through a clamp, so that the exhibition is facilitated.

When not needing the exhibition, at first the second rope 17 of pulling connection on gag lever post 10, make gag lever post 10 break away from with ring channel 12, alright at this moment with outside slip sleeve 5, after sleeve 5 outwards removes, loosen second rope 17, gag lever post 10 can reset under the effect of spring leaf 11 this moment, make first pin 14 shrink into in the second blind hole simultaneously, alright break away from sleeve 5 with bracing piece 4 completely this moment, make sleeve 5, drum 6, bracing piece 4 be in the detached condition once more, and compress bracing piece 4, withdraw the drawing, and later adorn each part and device with the box.

When the building is displayed, especially for buildings with structures like shopping malls and the like, the layout of each floor is often not the same, and after an investor sees a certain floor, the drawings in the cylinder 6 above the floor can be all contracted into the cylinder 6, or the floors above the floor can be rotated to be in the opposite direction of the floor, so that the investor or a consumer can conveniently watch the drawings.

The invention has the advantages that the left and right display devices are arranged, namely the left and right sides are provided with the rotating shafts and other mechanisms, and the corresponding sliding and rotating are set, so that the rich display effect can be realized, and the more gorgeous display can be shown through the shape design of a plurality of same devices, thereby bringing visual feast to audiences.

According to the invention, the supporting rod 4 and the rotating shaft are connected through the telescopic mechanism, so that the whole device is compressed, and meanwhile, the cylinder 6 and the supporting rod 4 are also in a detachable state, so that the whole device is greatly reduced in volume in a contracted state, is convenient to carry and transport, and can protect drawings and prevent the drawings from being damaged.

In consideration of convenient disassembly, the sleeve 5, the annular groove 12, the first pin 14, the limiting rod 10, the spring piece 11 and the like are ingeniously arranged at the joint of the cylinder 6 and the supporting rod 4, so that the effects of conveniently adjusting the display angle of the drawing, fixing the drawing and disassembling are achieved, the operation is convenient, the drawing can be clamped only by sliding and pushing, and the second rope 17 can be loosened by pulling.

Claims

1. A quick-release type multilayer display device for city planning comprises a flat plate (1), and is characterized in that two slide blocks (2) capable of moving left and right along the flat plate (1) are respectively arranged on the front side and the rear side of the flat plate (1), the slide blocks (2) on the left side and the right side respectively correspond to each other front and rear sides, a rotatable first rotating shaft (3) is connected between the front slide block and the rear slide block (2) on the same side, a plurality of support rods (4) which are parallel to the first rotating shaft (3) and are arranged up and down are arranged above the first rotating shaft (3), and telescopic mechanisms are connected between every two adjacent support rods (4) and between the support rods (4) and the first rotating; the support rods (4) are not rotatable, a rotatable sleeve (5) is sleeved at each of the front end and the rear end of each support rod (4), the sleeves (5) can move back and forth along the support rods (4), a detachable hollow cylinder (6) parallel to the support rods (4) is mounted on each of the front sleeve and the rear sleeve (5), a rotatable second rotating shaft (7) penetrates through the cylinder (6), a torsion spring (8) is arranged between each second rotating shaft (7) and the cylinder (6), and a connecting rod (9) capable of swinging back and forth is respectively arranged at each of the front end and the rear end of the cylinder (6);

the front end and the rear end of each supporting rod (4) are respectively hinged with a plurality of limiting rods (10), the inner ends of the limiting rods (10) can swing left and right and can be arranged in the supporting rods (4), and spring pieces (11) are arranged between the limiting rods (10) and the supporting rods (4); the inner edge surface of the sleeve (5) is provided with an annular groove (12), a plurality of first grooves (13) penetrating through the front side surface and the rear side surface of the sleeve (5) are uniformly distributed on the inner edge surface of the sleeve (5) in the circumferential direction, a plurality of first pins (14) which are distributed in the radial direction and can move along the radial direction of the support rod (4) are arranged on the support rod (4), a first rope (15) is connected between each first pin (14) and a corresponding limiting rod (10), and the spring piece (11) can be reset to enable the first pins (14) to be arranged in the support rod (4) through the limiting rod (10) and the first rope (15); the first pin (14) is located on the outer side of the limiting rod (10), a return spring (16) is arranged on the first pin (14), a plurality of radial second blind holes are uniformly distributed on the inner edge surface of the supporting rod (4) in the circumferential direction, the first pin (14) is arranged in the second blind holes and can move along the second blind holes, and the return spring (16) is located between the first pin (4) and the bottoms of the second blind holes; when the sleeve (5) moves inwards, the limiting rod (10) is firstly extruded to approach to the axis of the supporting rod (4), and meanwhile, the first pin (14) is placed in the first groove (13); after the sleeve (5) continues to move inwards along the support rod (4), the limiting rod (10) is arranged in the annular groove (12) on the inner edge surface of the sleeve (5);

the end part of each limiting rod (10) is connected with a second rope (17), and the other ends of the second ropes (17) are connected with each other and are arranged outside the supporting rod (4); during the dismantlement, second rope (17) on gag lever post (10) is connected in the pulling, make gag lever post (10) break away from with ring channel (12), alright outside slip sleeve (5) this moment, after sleeve (5) outwards removed, loosen second rope (17), gag lever post (10) can reset under the effect of spring leaf (11) this moment, make first pin (14) receive simultaneously and retract in the second blind hole, alright break away from sleeve (5) with bracing piece (4) completely this moment, make sleeve (5), drum (6), bracing piece (4) are in the detached state once more, and compression bracing piece (4).

2. The quick-release multilayer display device for city planning according to claim 1, wherein a T-shaped groove is formed in the flat plate (1), a T-shaped block matched with the T-shaped groove is arranged at the lower end of the sliding block (2), the T-shaped block is arranged in the T-shaped groove and moves left and right along the T-shaped groove, a vertical set screw (18) is connected to the sliding block (2) in a threaded manner, and the lower end of the set screw (18) can be arranged in the T-shaped groove.

3. The quick-release multilayer display device for city planning according to claim 1, wherein a plurality of radial second grooves (19) are uniformly distributed on the circumference of the first rotating shaft (3) in the sliding block (2), a plurality of first blind holes corresponding to the second grooves (19) one by one are arranged on the sliding block (2), second pins (20) capable of moving along the first blind holes are arranged in the first blind holes, a pressure spring is arranged between the second pins (20) and the first blind holes, and the second pins (20) can be arranged in the second grooves (19).

4. The quick-release multilayer display device for city planning according to claim 1, wherein the telescopic mechanism is formed by hinging a plurality of telescopic units in a tail-to-tail manner, each telescopic unit comprises a pair of connecting rods (21) with hinged middle parts, two fixing blocks (22) capable of sliding along the first rotating shaft (3) are sleeved on the first rotating shaft (3), the end parts of the connecting rods (21) are hinged on the fixing blocks (22), meanwhile, the cross section of the supporting rod (4) is square, and the inner edge surface of each fixing block (22) is also square.

5. The quick-release multilayer display device for city planning as claimed in claim 1, wherein the outer edge surface of the sleeve (5) is provided with a protruding block (23), the outer edge surface of the cylinder (6) is provided with a T-shaped groove matched with the protruding block (23), and the protruding block (23) can be placed in the T-shaped groove and can move back and forth along the T-shaped groove.

6. The quick-release multi-layer display device for city planning according to claim 1, wherein the outer edge surface of the cylinder (6) is provided with an opening, one end of the connecting rod (6) is hinged on the cylinder (6), and the hinged points of the connecting rod (9) and the cylinder (6) are respectively positioned at the front side and the rear side of the opening and have a certain friction force.