Chassis left-right swinging device and chassis

Abstract

A swing seat is hinged to a base in the front-back direction, the swing seat can obliquely swing left and right relative to the base, a torsional spring is arranged in a containing space of the base, the torsional spring acts on the swing seat, and when the swing seat swings, the torsional spring can act on the swing seat to deform and generate reset elastic force. In addition, the chair seat can be self-adaptive to forward leaning and backward leaning of the user to ascend and descend. The chair seat can swing left and right and also can be lifted by self-adapting to the forward and backward leaning actions of the user, so that the discomfort of the user due to long-time sitting can be relieved; as an elastic piece, the torsion spring not only provides buffering power for left-right swing of the swing seat to improve the comfort of a user during use, but also can assist the swing seat to reset by reset elastic force generated by the torsion spring; the torsion spring is arranged in the containing space of the base, the structure of the base is reasonably utilized, the overall size of the chassis is reduced, and cost is saved.

Description

Technical Field

[0001] The utility model relates to a seat chassis, in particular to a chassis left-right swinging device and a chassis. Background Art

[0002] In order to relieve users' fatigue caused by long periods of sitting, existing chair manufacturers design the seat chassis to be dynamic. The seat with a dynamic chassis can rise and fall or swing left and right to adapt to the user's leaning forward or backward or body swinging movements.

[0003] In the design of the chair seat being able to swing left and right, a swing reset mechanism is usually provided for comfort of swinging left and right. However, such a reset mechanism is usually provided on both sides of the base and additional support frames are required, so that the size of the base will be large, resulting in a large size and heavy weight of the overall seat chassis, which increases the manufacturing and transportation costs.

[0004] For example, the dynamic tray disclosed in the authorization announcement number CN211092836U has a swing reset mechanism including a supporting part and a spring. The left and right ends of the bottom plate base also extend upward with side plates, the supporting part is fixedly connected to the side plates, and the upper and lower ends of the spring respectively abut against the top plate and the supporting part. The bottom plate base not only extends the side plates, but also fixes the supporting part outwardly. The top plate also needs to reserve a width and space to cooperate with the spring, which makes the overall width direction of the seat chassis wider, increasing the size and weight of the chassis. Summary of the invention

[0005] The purpose of the utility model is to overcome the deficiencies existing in the above-mentioned prior art and to provide a left-right swinging device for a chassis. The swinging seat is hinged in the front-rear direction of the base. The swinging seat can tilt and swing left-right relative to the base. A torsion spring is arranged between the base and the swinging seat. When the swinging seat swings, the torsion spring can act on the swinging seat to deform and generate a restoring elastic force, which not only increases the user's comfort but also helps to reset the swinging seat. The torsion spring is arranged in the accommodating space of the base, which reasonably utilizes the structure of the base and reduces the overall size of the chassis.

[0006] Furthermore, a chassis is provided, which not only includes the above-mentioned left and right swinging device, but also includes a device that allows the support seat to rise and fall as the user leans forward or backward, so that the seat can rise and fall or swing left and right according to the user's leaning forward or backward or tilting left and right, thereby increasing the user's sitting comfort.

[0007] The technical solution of the utility model is achieved in this way:

[0008] A chassis left-right swing device comprises a base, a swing seat hinged to the base at the center line of the base in the front-rear direction, and the swing seat can tilt and swing left-right relative to the base; a accommodating space is formed in the base, and a torsion spring is arranged in the accommodating space, and the torsion spring acts on the swing seat, and when the swing seat tilts and swings to one side, the torsion spring can deform to generate a restoring elastic force, thereby helping the swing seat to reset or tilt and swing to the other side.

[0009] The setting of the torsion spring ensures that when the swing seat tilts left and right relative to the base, the swing action can be buffered and the reset elastic force generated by the torsion spring can help the swing seat to reset; the torsion spring is set in the accommodating space of the base, which reasonably utilizes the structure of the base and reduces the overall size of the chassis.

[0010] Preferably, the base and the swing seat are frame structures, and the front and rear sides of the base and the front and rear sides of the swing seat are hinged through the front and rear axles along the center line of the base. The frame structure can carry more functions; the setting of the front and rear axles can not only save the material of the axle, but also set other functions in the space between the front and rear axles.

[0011] Preferably, either the front axle or the rear axle extends into the accommodation space, and at least one pair of torsion springs are mounted on the front axle or the rear axle extending into the accommodation space. The torsion springs are mounted directly on the front axle or the rear axle, which is easy to install and does not require space outside the base, making the chassis structure compact.

[0012] Preferably, the base and the swing seat are frame structures, and the front and rear of the base and the front and rear of the swing seat are hinged through a swing shaft along the center line of the chassis. The swing shaft is a whole long shaft that runs through the accommodation space, and at least one pair of torsion springs are sleeved on the swing shaft. The frame structure can carry more functions; the whole shaft is convenient for installation as a hinge shaft; the torsion spring is directly sleeved on the swing shaft, which is simple to install, and there is no need to reserve space outside the base, making the chassis structure compact.

[0013] Preferably, the inner top surface of the swing seat symmetrically extends downwards with vertical plates on both sides in the middle, and each torsion spring has a torque arm a and a torque arm b, one of which abuts against the inner bottom surface of the base, and the other torque arm b abuts against the side surface of the vertical plate; the left and right inner sides of the two vertical plates abut against the other torque arms b of the two torsion springs respectively. The base is fixed, and the swing seat swings. When the swing seat swings, the vertical plates swing together to squeeze the torque arm b, and the torque arm a abuts against the inner bottom surface of the base, thus generating a reset elastic force; the left and right inner sides of the two vertical plates abut against the torque arm b so that the reset elastic force can be generated when the swing seat swings left and right.

[0014] As a preference, it also includes a swing locking mechanism, which includes a latch control assembly and a locking latch, and the latch control assembly can drive the locking latch to move; side wings are symmetrically extended from the left and right sides of the front of the swing seat, and the side wings include wing plates with vertically bent edges, and side ears are symmetrically extended from the left and right sides of the front of the base, and the side ears include ear plates with vertically bent edges; the wing plates and the ear plates are staggered up and down in some positions, and guide holes and pin holes are provided in the staggered parts, and the locking pin is inserted in the guide hole, and the locking pin is moved under the control of the latch control assembly. When the locking pin is inserted in the guide hole and the pin hole at the same time, the swing seat is in a locked state and cannot tilt and swing left and right; when the locking pin leaves the pin hole and is only inserted in the guide hole, the swing seat is unlocked and can tilt and swing left and right. When the user does not need the seat to swing left and right, the swing locking mechanism can lock the swing function to meet the needs of the user; the locking latches of the swing locking mechanism are arranged on both sides of the swing seat of the base to increase the locking torque and enhance the locking effect.

[0015] Furthermore, a chassis is provided, which includes the above-mentioned chassis left-right swing device, a bracket for supporting a chair seat, and a crank acting on the bracket, the crank is in an inclined state, and the crank is symmetrically arranged at the left and right ends of the swing seat, and a mounting plate for connecting with the chair back is fixed to the rear of the crank; the upper end of the crank is hinged to the bracket through a third pin shaft; the lower end of the crank is hinged to the swing seat through a first pin shaft. The crank, the bracket and each pin shaft constitute a crank-connecting rod mechanism, and the mounting plate is connected to the chair back. When the user leans against the chair back or leans forward away from the chair back, the crank can drive the bracket to rise and fall, reducing the "back rubbing" feeling and increasing the comfort of the user leaning forward and backward.

[0016] Preferably, the first pin passes through the waist-shaped limiting holes preset on the left and right sides of the base. When the swing seat swings left and right, the first pin moves up and down in the waist-shaped limiting holes, so that the swing seat will not hit the base to produce abnormal noise during the swing process.

[0017] Preferably, a guide mechanism is provided between the rear end of the bracket and the swing seat, the bracket includes a support plate and vertical plates hanging down on the left and right sides of the support plate, the vertical plates are provided with a guide mechanism, the guide mechanism includes a limit slot and a second pin, the limit slot is provided on one of the vertical plates or the swing seat, the second pin is connected to the other of the vertical plates or the swing seat, and the second pin is inserted in the limit slot, when the mounting plate drives the crank to rotate synchronously, the bracket rises and falls, and the second pin slides relative to the limit slot. The setting of the guide mechanism enables the bracket to rise and fall within the effective distance of the limit slot and move smoothly.

[0018] The design starting point, concept and beneficial effects of the utility model using the above technical solution are:

[0019] The present invention provides a chassis left-right swinging device and a chassis, wherein a swing seat is hinged in the front-rear direction of the base, and the swing seat can tilt and swing left-right relative to the base, and a torsion spring is arranged in the accommodating space of the base itself, and the torsion spring acts on the swing seat. When the swing seat swings, the torsion spring can act on the swing seat to deform and generate a restoring elastic force, thereby helping the swing seat to reset or tilt and swing to the other side. In addition, the chair seat can rise and fall adaptively according to the user's forward and backward tilting.

[0020] In addition to being able to swing left and right, the chair seat can also rise and fall adaptively according to the user's leaning forward and backward movements, which can relieve the user's discomfort caused by sitting for a long time; the torsion spring as an elastic member not only provides a buffering force for the left and right swing of the swing seat to improve the user's comfort when using it, but the restoring elastic force generated by the torsion spring can also help the swing seat to reset; the torsion spring is set in the accommodating space of the base, which reasonably utilizes the structure of the base, reduces the overall size of the chassis, and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is an overall schematic diagram of the utility model;

[0022] Figure 2 It is an explosion diagram of the utility model;

[0023] Figure 3 It is a front schematic diagram of the left-right swing device of the utility model in a horizontal state;

[0024] Figure 4 It is a front view schematic diagram of the left-right swinging device of the utility model in a leftward swinging state;

[0025] Figure 5 It is a front view schematic diagram of the left-right swinging device of the utility model in a rightward swinging state;

[0026] Figure 6 It is a side view of the support base of the chassis of the utility model in a raised state;

[0027] Figure 7 It is a partially cutaway stereoscopic view of the left-right swing device of the utility model in a locked state;

[0028] Figure 8 This is an exploded view of the left-right swing device of the utility model;

[0029] Fig. 9 It is a partial cross-sectional side view of the left-right swing device of the utility model in a locked state;

[0030] Fig.10 It is a partial cutaway stereoscopic view of the left-right swing device of the utility model in an unlocked state;

[0031] Fig.11 It is a partial sectional side view of the left-right swing device of the utility model when it is unlocked.

[0032] The reference numerals of the figures are as follows: swing seat 1; side wing 101; side wing body 1011; wing plate 102; guide hole 103; vertical plate 104; base 2; side ear 201; side ear body 2011; ear plate 202; support ear 2021; lug 2022; pin hole 203; waist-shaped limiting hole 204; torsion spring 3; torque arm a300; torque arm b301; front axle 4; rear axle 5; swing locking mechanism 6; latch control assembly 601; fixing frame 6011; wire control 6012; Outer sleeve 60121; pull wire 60122; pull wire head 60123; dial plate 6013; baffle 60131; dial slot 60132; locking pin 602; compression spring 603; toggle torsion spring 604; elastic arm 1 6041; elastic arm 2 6042; fastening screw 605; crank 7; bracket 8; supporting plate 801; vertical plate 802; mounting plate 9; third pin shaft 10; first pin shaft 11; guide mechanism 12; limiting slot 1201; second pin shaft 1202. DETAILED DESCRIPTION

[0033] The present invention is further described below with reference to a specific embodiment. In a structure in which the seat can swing left and right, a swing reset mechanism is provided to ensure the comfort of swinging left and right. However, such a reset mechanism usually adds fixed abutment structures on both sides of the base, thereby increasing the size of the base, causing the overall size of the seat chassis to become larger and the weight to increase.

[0034] Based on the above reasons, this embodiment makes improvements, such as Figure 1-11 As shown, a chassis left-right swing device includes a base 2 and a swing seat 1. The base 2 and the swing seat 1 are frame structures. The base 2 and the swing seat 1 are hinged at the center line of the front-back direction of the base 2. The swing seat 1 can tilt and swing left-right relative to the base 2. The swing seat 1 is horizontal relative to the base 2. Figure 3 , the swing seat 1 is tilted to the left relative to the base 2. Figure 4 , the swing seat 1 is tilted to the right relative to the base 2. Figure 5 .

[0035] Specific instructions, such as Figure 8 As shown, the above-mentioned articulation can be in the form of passing through the front axle 4 and the rear axle 5 along the center line of the base, and respectively articulating the front and rear sides of the base 2 to the front and rear sides of the swing seat 1; or it can be in the form of passing through a whole swing axis along the center line of the base, and articulating the front and rear of the base 2 to the front and rear of the swing seat 1 (not shown); the former saves materials and the space in the middle can be used to arrange other functions, and the latter is easy to install, so any form of articulation can be selected according to the space size of the chassis and the layout of the required structure.

[0036] Further explanation, such as Figure 7 and Figure 8As shown, a receiving space is formed in the base 2 on the swing center line. If the above-mentioned hinged form is the front axle 4 and the rear axle 5, then any one of the front axle 4 or the rear axle 5 extends into the receiving space, and at least one pair of torsion springs 3 is sleeved on the front axle 4 or the rear axle 5 extending into the receiving space; if the above-mentioned hinged form is a swing shaft, the swing shaft runs through the receiving space, and at least one pair of torsion springs 3 (not shown) is sleeved on the swing shaft; the top surface of the swing seat 1 has vertical plates 104 extending downward symmetrically on both sides in the middle, and the two vertical plates 104 are welded on both sides of the receiving space. The torsion springs 3 are in the receiving space, and each torsion spring 3 has a torque arm a300 and a torque arm b300. 301, one of the torque arms a300 abuts against the inner bottom surface of the base 2, and the other torque arm b301 abuts against the side surface of the vertical plate 104; when the swing seat 1 tilts and swings to one side, the torque arm a300 abutting against the inner bottom surface of the base 2 is fixed, and the torque arm b301 abutting against the side surface of the vertical plate 104 tilts to one side with the swing seat, so the torsion spring 3 can be deformed to generate a restoring elastic force to help the swing seat 1 to reset or tilt and swing to the other side; in order to generate a restoring elastic force when the swing seat swings left and right, the left and right inner sides of the two vertical plates 104 respectively abut against the other torque arms b301 of the two torsion springs 3.

[0037] To further explain, Figure 7 and Figure 8 As shown, in order to meet the needs of users who sometimes do not need the seat to swing left and right, the left and right swing device of the chassis is provided with a swing locking mechanism 6, which includes a latch control component 601 and a locking latch 602, and the latch control component 601 can drive the locking latch 602 to move; side wings 101 are symmetrically extended from the left and right sides of the front of the swing seat 1, and the side wings 101 include wing plates 102 with vertically bent edges, and side ears 201 are symmetrically extended from the left and right sides of the front of the base 2, and the side ears 201 include ear plates 202 with vertically bent edges; the wing plates 102 and the ear plates 202 are staggered up and down at some positions, and a guide hole 103 and a pin hole 203 are provided at the staggered part, and the locking latch 602 is inserted in the guide hole 103, and the locking latch 602 is moved under the control of the latch control component 601; as shown Figure 3 and Fig. 9 As shown, when the locking pin 602 is inserted into the guide hole 103 and the pin hole 203 at the same time, the swing seat 1 is in a locked state and cannot tilt or swing left or right; Figure 4 , Figure 5 and Fig.11 As shown, when the locking pin 602 leaves the pin hole 203 and is only inserted into the guide hole 103, the swing seat 1 is unlocked and can be tilted and swung left and right.

[0038] To further explain, Figure 8As shown, the side wing 101 includes a horizontally arranged side wing body 1011 and a wing plate 102 vertically bent from the edge of the side wing body 1011, the side ear 201 includes a side ear body 2011 and an ear plate 202 vertically bent from the edge of the side ear body 2011; the ear plate 202 includes a support ear 2021 perpendicular to the left and right side walls of the base, the support ear 2021 continues to extend upward to form a lug 2022, the lug 2022 is staggered with the adjacent wing plate 102, and the lug 2022 is located on the outside of the adjacent wing plate 102, the pin hole 203 is opened on the lug 2022, and the guide hole 103 is opened on the wing plate 102.

[0039] To further explain, Fig.10 As shown, the latch control assembly 601 includes a fixing frame 6011 fixed on the front wall of the swing seat 1, a dial plate 6013 hinged on the upper surface of the swing seat 1, and a wire control 6012. The dial plate 6013 is L-shaped, with a baffle 60131 hanging down at one end and a dial groove 60132 at the other end. The wire control 6012 includes an outer sleeve 60121 and a pull wire 60122 that moves telescopically in the outer sleeve 60121. The outer sleeve 60121 is installed on the fixing frame 6011. The part of the pull wire 60122 exposed from the outer sleeve 60121 is connected to a pull wire head 60123. The pull wire head 60123 abuts against the outer side of the baffle 60131, and the inner side of the baffle 60131 is A compression spring 603 is also provided between the surface and the fixing frame 6011. The compression spring 603 is set along the extension direction of the pull wire 60122. A toggle torsion spring 604 is provided on the left and right sides of the upper surface of the swing seat 1. The ring in the middle of the toggle torsion spring 604 is mounted on a fastening screw 605 connected to the upper part of the swing seat 1 so that the toggle torsion spring 604 as a whole rotates around the fastening screw 605. The toggle torsion spring 604 has an elastic arm 1 6041 and an elastic arm 2 6042 respectively arranged on both sides of the fastening screw 605. The elastic arm 1 6041 is bent and inserted into the toggle groove 60132, and the elastic arm 2 6042 is bent and passes through the movable hole 1021 reserved on the wing plate 102 and then connected to the locking pin 602.

[0040] To further explain, Fig. 9 As shown, when the pull wire 60122 moves in the shortening direction, the pull wire head 60123 pulls the dial plate 6013 to rotate counterclockwise, and the dial plate 6013 compresses the compression spring 603 to generate a restoring elastic force. When the locking pin 602 moves synchronously and is inserted into the guide hole 103 and the pin hole 203 at the same time, the swing seat 1 is in a locked state; Fig.11 As shown, when the pull wire 60122 is released and moves in the lengthening direction, the compression spring 603 releases the elastic force to help the pull wire head 60123, the dial plate 6013, the torsion spring 604, and the locking pin 602 to reset. When the locking pin 602 leaves the pin hole 203 and is only inserted into the guide hole 103, the swing seat 1 is unlocked.

[0041] In general, Figure 2 and Figure 6 As shown, a chassis includes the above-mentioned chassis left-right swinging device, a bracket 8 for supporting a seat, and a crank 7 acting on the bracket 8, the crank 7 is in an inclined state, and the crank 7 is symmetrically arranged at the left and right ends of the swing seat 1, and a mounting plate 9 for connecting with the seat back is fixed to the rear of the crank 7; the upper end of the crank 7 is hinged to the bracket 8 through a third pin shaft 10; the lower end of the crank 7 is hinged to the swing seat 1 through a first pin shaft 11. In order to limit the swing range of the swing seat 1 and prevent the swing seat 1 from hitting the base 2 to produce abnormal noise, waist-shaped limiting holes 204 are preset on the left and right sides of the base 2, and the first pin shaft 11 passes through the waist-shaped limiting hole 204. When the swing seat 1 swings left and right, the first pin shaft 11 is in the waist-shaped limiting hole 20 4 moves up and down; a guiding mechanism 12 is provided between the rear end of the bracket 8 and the swing seat 1, the bracket 8 includes a supporting plate 801 and vertical plates 802 hanging down on the left and right sides of the supporting plate 801, the vertical plates 802 are provided with a guiding mechanism 12, the guiding mechanism 12 includes a limiting groove 1201 and a second pin shaft 1202, the limiting groove 1201 is provided on one of the vertical plates 802 or the swing seat 1, the second pin shaft 1202 is connected to the other of the vertical plates 802 or the swing seat 1, and the second pin shaft 1202 is inserted in the limiting groove 1201, when the mounting plate 9 drives the crank 7 to rotate synchronously, the second pin shaft 1202 and the limiting groove 1201 slide relative to each other, and the bracket 8 rises and falls.

[0042] The above schematically describes the present invention and its implementation methods, which are not restrictive. The drawings show only one implementation method of the present invention, and the actual structure is not limited thereto. Therefore, if ordinary technicians in this field are inspired by it and design structural methods and embodiments similar to the technical solution without creativity without departing from the purpose of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A chassis left-right swing device, characterized in that: The invention comprises a base (2), and a swing seat (1) hinged to the base (2) at the center line of the base (2) in the front-rear direction, wherein the swing seat (1) can tilt and swing left and right relative to the base (2); a receiving space is formed in the base (2), and a torsion spring (3) is arranged in the receiving space, and the torsion spring (3) acts on the swing seat (1), and when the swing seat (1) tilts and swings to one side, the torsion spring (3) can be deformed to generate a restoring elastic force, thereby helping the swing seat (1) to reset or tilt and swing to the other side.

2. A chassis left-right swinging device according to claim 1, characterized in that: The base (2) and the swing seat (1) are frame structures, and the front and rear sides of the base (2) and the front and rear sides of the swing seat (1) are respectively hinged along the center line of the base through a front axle (4) and a rear axle (5).

3. The chassis left-right swinging device according to claim 2, characterized in that: Either the front axle (4) or the rear axle (5) extends into the accommodation space, and at least one pair of torsion springs (3) is sleeved on the front axle (4) or the rear axle (5) extending into the accommodation space.

4. The chassis left-right swinging device according to claim 1, characterized in that: The base (2) and the swing seat (1) are of a frame structure. The front and rear of the base (2) and the front and rear of the swing seat (1) are hingedly connected via a swing shaft along the center line of the base. The swing shaft is a whole long axis that passes through the accommodation space. At least one pair of torsion springs (3) is sleeved on the swing shaft.

5. A chassis left-right swinging device according to claim 3 or 4, characterized in that: The inner top surface of the swing seat (1) has vertical plates (104) symmetrically extending downward on both sides in the middle, and each torsion spring (3) has a torque arm a (300) and a torque arm b (301), wherein one torque arm a (300) abuts against the inner bottom surface of the base (2), and the other torque arm b (301) abuts against the side surface of the vertical plate (104); the left and right inner side surfaces of the two vertical plates (104) respectively abut against the other torque arms b (301) of the two torsion springs (3).

6. The chassis left-right swinging device according to claim 1, characterized in that: The invention also comprises a swing locking mechanism (6), the swing locking mechanism (6) comprising a latch control component (601) and a locking latch (602), the latch control component (601) being capable of driving the locking latch (602) to move; side wings (101) extending symmetrically from the left and right sides of the front of the swing seat (1), the side wings (101) comprising wing plates (102) with vertically bent edges; side ears (201) extending symmetrically from the left and right sides of the front of the base (2), the side ears (201) comprising ear plates (202) with vertically bent edges; the wing plates (102) and the ear plates (202) are connected to each other. ) There are vertical staggered portions in some positions, and a guide hole (103) and a pin hole (203) are provided in the vertical staggered portions. The locking pin (302) is inserted into the guide hole (103). The locking pin (302) is moved under the control of the latch control component (601). When the locking pin (302) is inserted into the guide hole (103) and the pin hole (203) at the same time, the swing seat (1) is in a locked state and cannot tilt or swing left or right. When the locking pin (302) leaves the pin hole (203) and is only inserted into the guide hole (103), the swing seat (1) is unlocked and can tilt or swing left or right.

7. A chassis, characterized in that: It comprises the chassis left-right swinging device as claimed in claim 1, a bracket (8) for supporting a seat, and a crank (7) acting on the bracket (8), wherein the crank (7) is in an inclined state, and the crank (7) is symmetrically arranged at the left and right ends of the swing seat (1), and a mounting plate (9) for connecting with a seat back is fixed to the rear of the crank (7); the upper end of the crank (7) is hinged to the bracket (8) via a third pin shaft (10); and the lower end of the crank (7) is hinged to the swing seat (1) via a first pin shaft (11).

8. A chassis according to claim 7, characterized in that: The first pin shaft (11) passes through waist-shaped limiting holes (204) preset on the left and right sides of the base (2).

9. A chassis according to claim 7, characterized in that: A guide mechanism (12) is provided between the rear end of the support seat (8) and the swing seat (1). The support seat (8) comprises a support plate (801) and vertical plates (802) hanging down from left and right sides of the support plate (801). The vertical plates (802) are provided with a guide mechanism (12). The guide mechanism (12) comprises a limit groove (1201) and a second pin shaft (1202). The limit groove (1201) is provided on one of the vertical plates (802) or the swing seat (1). The second pin shaft (1202) is connected to the other of the vertical plates (802) or the swing seat (1). The second pin shaft (1202) is inserted into the limit groove (1201). When the mounting plate (9) drives the crank (7) to rotate synchronously, the support seat (8) rises and falls, and the second pin shaft (1202) and the limit groove (1201) slide relative to each other.

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