WO2024067881A1

WO2024067881A1 - Chair and adjustable chassis thereof

Info

Publication number: WO2024067881A1
Application number: PCT/CN2023/123227
Authority: WO
Inventors: 王江林; 王郑兴; 鲍家华; 金剑; 李德才
Original assignee: 恒林家居股份有限公司
Priority date: 2022-09-29
Filing date: 2023-10-07
Publication date: 2024-04-04
Also published as: CN115517494A

Abstract

A chair and an adjustable chassis thereof. The adjustable chassis comprises a bottom base (1), a top base (3), a tail base (2), a tension spring (65), a first adjustment base (62), and a first mounting base (64); the bottom base (1) is hingedly connected to the tail base (2) by means of a first hinge shaft (4); the front of the tail base (2) is hingedly connected to the top base (3) by means of a second hinge shaft (5); the second hinge shaft (5) is located above the front side of the first hinge shaft (4); the bottom of the first adjustment base (62) is hingedly connected to the bottom base (1); the top of the first adjustment base (62) is hingedly connected to the first mounting base (64) and the top base (3) by means of a fourth hinge shaft (63); one end of the tension spring (65) is connected to the first mounting base (64), and the other end of the tension spring (65) is connected to the front of the base (1). The chassis has a larger adjustment space, and is lighter and thinner.

Description

A chair and an adjustable chassis thereof

Technical Field

The invention relates to the field of home furnishings, and in particular to a chair and an adjustable chassis thereof.

Background technique

The chassis of a chair, also known as a tray, is an important part of the chair that connects the seat, back and legs. The current swivel chair tray is generally composed of an upper tray, a lower support beam, a rotating shaft and a spring device. After the upper turntable is fixed to the back of the swivel chair seat, the swivel chair can be tilted and reclined appropriately around the rotating shaft and can be automatically restored.

The patent document with publication number CN102846068B discloses a swivel chair chassis, including a bottom plate connected to a gas rod, the bottom plate supporting the entire chassis and the seat and backrest; a support plate is provided on the left and right sides of the bottom plate in the vertical direction, the support plate is fixedly connected to the bottom plate, a seat plate for mounting the seat is provided above the two support plates in the horizontal direction, the front and rear sides of the bottom plate are respectively provided with a support frame and a backrest bracket inclined toward the front of the swivel chair, the lower parts of the support frame and the backrest bracket are hinged to the two support plates, the front and rear sides of the seat plate are respectively hinged to the top of the support frame and the backrest bracket, the backrest bracket is connected to the backrest through a connecting steel plate, and the backrest bracket is connected to an elastic reset device for tilting it toward the front of the swivel chair. Specifically, the support frame is in a square shape, including two pins arranged in parallel up and down, and the two pins are fixedly connected by two connecting rods arranged in parallel left and right; of course, one connecting rod can also be provided; the backrest bracket is also provided with two pins arranged in parallel up and down, and the pins of the backrest bracket are inserted into the side panels on the left and right sides of the backrest bracket; the pins at the lower ends of the support frame and the backrest bracket are hinged to the support plate, and four lugs are provided at the lower end of the seat plate, and the seat plate is hinged to the pins at the upper ends of the support frame and the backrest bracket by means of the lugs. The elastic reset device is a spring, one end of the spring is connected to the pin at the upper end of the backrest bracket, and the other end of the spring is connected to the pin at the lower end of the support frame. In actual use, 2 to 4 springs can be provided according to actual needs.

In the prior art, the front part of the seat plate and the front part of the bottom plate are hinged by two connecting rods arranged in parallel on the left and right sides, the rear end of the seat plate and the rear end of the bottom plate are hinged by the side plates on the left and right sides of the backrest bracket, and the two ends of the spring are respectively connected to the backrest bracket and the bottom plate; when the chassis is adaptively adjusted, the backrest bracket directly acts on the seat plate, so that the backrest bracket directly drives the seat plate to swing, so that the thickness of the chassis only depends on the length of the side plates, making the chassis relatively thick and heavy.

technical problem

In order to solve the problem of heavy chair trays in the prior art, the purpose of the present invention is to provide a lighter and thinner chair and an adjustable chassis thereof, which can be adaptively adjusted to make the chair more comfortable, and during the adaptive adjustment process, the movement of the top seat relative to the rear seat is smaller, making the chair more stable.

Technical Solutions

In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an adjustable chassis, including a base, a top seat, a tail seat for installing a chair back and a tension spring, the base and the tail seat are hinged by a first hinge shaft, the top seat and the tail seat are hinged by a second hinge shaft, the tail seat includes two first connecting plates arranged symmetrically on the left and right, the two first connecting plates of the tail seat are hinged to the base by the first hinge shaft, and the front parts of the two first connecting plates of the tail seat are hinged to the bottom of the top seat by the second hinge shaft; it also includes a first adjustment seat, the bottom of the first adjustment seat is hinged to the base by a third hinge shaft, the top of the first adjustment seat is hinged to the top seat by a fourth hinge shaft, one end of the tension spring is connected to the fourth hinge shaft, and the other end of the tension spring is connected to the base through an adjustment device.

Preferably, it also includes a first mounting seat, the top of the first adjustment seat is hinged to the first mounting seat through a fourth hinge axis, the first adjustment seat is hinged to the top seat through the fourth hinge axis, one end of the tension spring is connected to the first mounting seat, and the other end of the tension spring is connected to the front of the base through an adjustment device; the adjustment device includes a second adjustment seat, a second mounting seat is fixed on the second adjustment seat, both ends of the tension spring are respectively connected to the first mounting seat and the second mounting seat, an adjustment screw is threadedly connected to the second adjustment seat, and the adjustment screw is installed on the base and can rotate.

Preferably, the second adjustment seat is provided with a bayonet, a nut is installed in the bayonet, and the adjustment screw passes through the nut and is threadedly connected; when the adjustment screw rotates, the nut can drive the second adjustment seat to move along the axis of the adjustment screw.

Preferably, a handle is fixed to one end of the adjusting screw, a pin is radially fixedly installed at the other end of the adjusting screw, and the handle is located outside the base.

Preferably, there are two tension springs and they are symmetrically arranged on the left and right, there are two first mounting seats and they are symmetrically arranged on the left and right, and there are two second mounting seats and they are symmetrically arranged on the left and right.

Preferably, the outer side surface of the first mounting seat and the outer side surface of the second mounting seat both have a spiral fixing groove, and the two ends of the tension spring are respectively clamped in the fixing groove of the first mounting seat and the fixing groove of the second mounting seat.

Preferably, a guide portion is raised on the base for preventing the second adjustment seat from lateral movement, a guide groove opening downward is provided at the bottom of the second adjustment seat, and the guide portion of the base is inserted into the guide groove at the bottom of the second adjustment seat from bottom to top.

Preferably, the chassis is further provided with two positioning grooves opening upward, the positioning grooves extending backwards and penetrating the base, and the two first connecting plates of the tailstock are respectively inserted into the two positioning grooves and are hinged to the base through the first hinge shaft.

Preferably, the base and the top seat are made of plastic.

A chair comprises the above-mentioned adjustable chassis.

Beneficial Effects

The beneficial effects of the technical solution of the present invention are as follows: the chassis has an adaptive function, providing users with a better use experience. Since the force-bearing positions in the chassis are not concentrated, the force of each component is more evenly distributed, thereby improving the service life and reliability of the chassis. During the adaptive adjustment of the chassis, the swing amplitude of the tail seat is much larger than the movement amplitude of the top seat, and when the top seat moves, the speed at which the front part of the top seat moves upward is faster than the speed at which the rear end of the top seat moves upward, thereby also making the support of the chair more stable. The chassis in the prior art is usually made of metal, so in order to increase the aesthetics of the chair, it is usually necessary to provide a shell cover outside the chassis. In the technical solution of the present invention, the top seat and the base are both made of plastic, so even without the shell cover, the beauty of the chair can still be maintained, the weight of the chair can be reduced, the structure of the chair can be simplified, the manufacturing difficulty of the chassis can be reduced, and the diversity of chassis styles can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural schematic diagram 1 of the adjustable chassis in the present invention.

FIG. 2 is a second structural schematic diagram of the adjustable chassis in the present invention.

FIG. 3 is a structural schematic diagram 1 of the chassis.

FIG. 4 is a second structural diagram of the chassis.

FIG. 5 is a schematic structural diagram of the second adjustment seat.

FIG. 6 is a schematic structural diagram of the base.

FIG. 7 is a schematic structural diagram of the first adjustment seat.

1. The camshaft of the first embodiment includes the following: 1. a base; 11. a baffle; 12. a first connection portion; 13. a second blocking portion; 14. a positioning groove; 15. a countersunk hole; 16. a mounting hole; 17. a guide portion; 18. a through hole; 2. a tailstock; 21. a second connection plate; 22. a first connection plate; 23. a third connection plate; 3. a top seat; 31. a shielding portion; 4. a first hinge axis; 5. a second hinge axis; 60. a fixing seat; 61. a third hinge axis; 62. a first adjustment seat; 621. a second connection portion; 622. a mounting opening; 63. a fourth hinge axis; 64. a first mounting seat; 65. a tension spring; 66. a second adjustment seat; 662. a through hole; 663. a second mounting seat; 664. a bayonet; 665. a guide groove; 667. a pin; 67. a nut; 68. an adjusting screw; 69. a handle; 7. a lever.

Best Mode for Carrying Out the Invention

Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise clearly specified.

In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

The front, back, left, and right directions described in the following embodiments are consistent with those of the chair product, with one side of the chair backrest being the back and the side opposite to the chair backrest being the front, and the front and back being further divided into left and right.

Embodiment 1:

As shown in Figures 1-4, an adjustable chassis includes a base 1 for connecting chair legs, a top seat 3 for installing a chair seat, a tail seat 2 for installing a chair back, and a tension spring 65 for adaptive adjustment. The base 1 and the tail seat 2 are hinged by a first hinge shaft 4, the top seat 3 and the tail seat 2 are hinged by a second hinge shaft 5, and the tail seat 2 includes two first connecting plates 22 symmetrically arranged on the left and right. The two first connecting plates 22 of the tail seat 2 are hinged to the base 1 through the first hinge shaft 4, and the front parts of the two first connecting plates 22 of the tail seat 2 are hinged to the top seat 3 through the second hinge shaft 5. The bottom is hinged; the chassis also includes a first adjustment seat 62 and a first mounting seat 64. The bottom of the first adjustment seat 62 is hinged to the base 1 through a third hinge shaft 61, and the top of the first adjustment seat 62 is hinged to the first mounting seat 64 through a fourth hinge shaft 63. The fourth hinge shaft 63 is hinged to the top seat 3, and the fourth hinge shaft 63 is located on the rear side of the second hinge shaft 5. One end of the tension spring 65 is connected to the first mounting seat 64, and the other end of the tension spring 65 is connected to the front of the base 1 through an adjusting device. The second hinge shaft 5 is located above the front side of the first hinge shaft 4.

The process of chassis adaptive adjustment is as follows: the user sits on the chair with his back against the chair back. After the chair back is subjected to force, the tail stock 2 is driven to swing with the first hinge axis 4 as the fulcrum; when the tail stock 2 swings, the front part of the tail stock 2 lifts the top seat 3 through the second hinge axis 5, so that the top seat 3 moves backward and upward around the first hinge axis 4; when the top seat 3 moves, the first mounting seat 64 and the first adjustment seat 62 are pulled through the fourth hinge axis 63, so that the first adjustment seat 62 swings backward around the third hinge axis 61, so that the first mounting seat 64 moves backward to stretch the tension spring 65, and then the tension spring 65 accumulates force; when the user's back leans forward or the user stands up, the tension spring 65 pulls the first mounting seat 64 to reset, and the first mounting seat 64 pulls the top seat and the first adjustment seat 62 to reset through the fourth hinge axis 63, and the top seat 3 drives the tail stock 2 to reset through the second hinge axis 5. When the tail stock 2 is reset, it can drive the chair back to move with the user's back.

In this way, in the above structure, with the first hinge axis as the fulcrum, a first lever arm is formed from the first hinge axis to the rear end of the tailstock, and a second lever arm is formed from the first hinge axis to the second hinge axis; with the second hinge axis as the fulcrum, a third lever arm is formed from the second hinge axis to the fourth hinge axis; with the fourth hinge axis as the fulcrum, a fourth lever arm is formed from the fourth hinge axis to the third hinge axis.

Such a setting can make the chassis have an adaptive function, providing users with a better use experience. Since the force position in the chassis is not concentrated, the force of each component is more uniform, which improves the service life and reliability of the chassis; and the chassis is thinner and lighter as a whole, and has a larger adjustment range by adjusting the length of each force arm. In addition, the connection structure between the tailstock, the top seat and the base is not concentrated at the front or rear end of the base, which makes the adjustment process of the chassis more stable and has better support rigidity.

In order to facilitate the installation of the tailstock 2, the top seat 3 and the base 1, in this embodiment, as shown in Figures 2, 5, 6 and 7, the base 1 has an installation cavity on the opening, and the left and right sides of the installation cavity are provided with positioning grooves 14 with the openings upward, and the positioning grooves 14 extend backward and penetrate the base 1, and the two first connecting plates 22 of the tailstock 2 are respectively inserted into the two positioning grooves 14, and the two first connecting plates 22 are respectively hinged to the middle position of the base 1 through the first hinge shaft 4, and the front parts of the two first connecting plates 22 are tilted upward and exceed the base 1, and the second hinge shaft 5 extends horizontally to connect the two first connecting plates 22 with the top seat 3. connected; there are two first connection parts 12 arranged on the left and right protruding in the installation cavity, and two second connection parts 621 arranged on the left and right protruding at the bottom of the first adjustment seat 62, the two first connection parts 12 are located between the two second connection parts 621, and the third hinge shaft 61 passes through the first connection part 12 and the second connection part 621 to hinge the base 1 and the first adjustment seat 62; in order to facilitate the installation of the third hinge shaft 61, a through hole 18 coaxial with the third hinge shaft 61 is opened on the side of the base 1, so that the third hinge shaft 61 can be inserted into the installation cavity through the through hole 18 to hinge the base 1 and the first adjustment seat 62. In order to increase the overall strength of the base, in this embodiment, criss-cross reinforcing ribs are arranged on the inner side of the installation cavity and the positioning groove 14.

In order to further improve the applicable groups of the chassis, as shown in Figures 2, 5, 6 and 7, in this embodiment, the adjustment device includes a second adjustment seat 66, a second mounting seat 663 is fixed on the second adjustment seat 66, the other end of the tension spring 65 is connected to the second mounting seat 663, and an adjustment screw 68 is threadedly connected to the second adjustment seat 66, and the adjustment screw 68 is rotatably connected to the base 1. In this way, the tension of the tension spring can be adjusted, the applicability of the chassis is improved, and a better use experience is provided for users.

In order to make the self-adaptation process of the chassis more stable, in this embodiment, as shown in FIG. 2-7, there are two tension springs 65 and they are symmetrically arranged, there are two first mounting seats 64 and they are symmetrically arranged, and there are two second mounting seats 663 and they are symmetrically arranged; the top of the first adjustment seat 62 has two mounting openings 622, one end of the first mounting seat 64 is inserted into the mounting opening 622, and the fourth hinge shaft 63 horizontally penetrates the first adjustment seat 62 and the two first mounting parts 64, thereby hingedly connecting the two first mounting parts 64 to the first adjustment seat 62; the adjustment screw 68 is located between the two second mounting seats 663. In this way, the tension of the chassis can be increased, and the symmetrically arranged tension springs can make the movement process of the chassis more stable.

In order to prevent the second adjustment seat from moving laterally, in this embodiment, as shown in Figures 4-6, two guide portions 17 are protruded in the installation cavity of the base 1, and the guide portion 17 is located in front of the first connecting portion 12. Two first blocking portions are protruded from the bottom of the second adjustment seat 66, and the first blocking portion is provided with a guide groove 665 opening downward. The two guide portions 17 are respectively inserted into the guide grooves of the two first blocking portions, so that the second adjustment seat 66 can only move in the longitudinal direction, thereby preventing the second adjustment seat from moving or rotating laterally.

In order to facilitate the installation of the tension spring, in this embodiment, as shown in FIG. 4 and FIG. 5 , the outer side surface of the first mounting seat 64 and the outer side surface of the second mounting seat 663 are both provided with a spiral fixing groove, and the two ends of the tension spring 65 are respectively wound in the fixing groove of the first mounting seat 64 and the fixing groove of the second mounting seat 663. In this way, the installation of the tension spring is facilitated, the angle of the first mounting seat and the second mounting seat is adjusted, and the difficulty of assembling the chassis is reduced.

In this embodiment, as shown in Fig. 2, Fig. 4 and Fig. 6, a second blocking portion 13 is protruded in the mounting cavity of the base 1, and the second blocking portion 13 is located in front of the first connecting portion 12, and is used to limit the forward tilting angle of the first adjustment seat 62; when the chassis is not subjected to force, the tension spring 65 can pull the first adjustment seat 62 to press on the second blocking portion 13. In this way, the tension spring can have sufficient pre-tightening force, so that a certain initial angle is maintained between the base and the first adjustment seat, reducing the difficulty of adaptive adjustment.

To facilitate the rotation of the screw, in this embodiment, as shown in Figures 2-6, a through hole 662 is provided on the second adjustment seat 66, and a nut 67 is also installed on the second adjustment seat 66, and the inner hole of the nut 67 is connected to the through hole 662 of the second adjustment seat 66; a countersunk hole 15 connected to the installation cavity is provided at the front of the base 1, and the countersunk hole 15 is rectangular, and a fixed seat 60 with an inner hole is clamped in the countersunk hole 15, and a ring-shaped fifth blocking portion is protruded from the front of the fixed seat 60. A handle 69 is fixedly installed at one end of the screw 68, and an annular sixth blocking portion is protruded on the handle 69. The fifth blocking portion is inserted into the sixth blocking portion, and the other end of the screw 68 passes through the fifth blocking portion, the inner hole of the fixed seat 60, and the through hole 662 of the second adjustment seat 66, and is threadedly connected to the nut 67 installed on the second adjustment seat 66; in order to prevent the nut 67 from falling off the screw 68, a pin 667 is also fixedly installed on the screw 68. To facilitate the installation of the nut, a plurality of fourth blocking parts are protruding from the second adjustment seat 66 and are arranged around the through hole 662. The fourth blocking part is located between the two second mounting seats 663. The plurality of fourth blocking parts enclose a bayonet 664 that matches the shape of the nut. The bayonet 664 is connected to the through hole 662. The nut 67 can be directly pressed into the bayonet 664 between the plurality of fourth blocking parts to prevent the nut 67 from rotating. The nut 67 is located on the inner side of the plurality of fourth blocking parts, and the nut 67 is abutted against the fourth blocking part, so that the nut 67 can be directly pressed between the plurality of fourth blocking parts. The plurality of fourth blocking parts can prevent the nut 68 from rotating.

In this embodiment, as shown in Figures 1-3, a baffle 11 is fixedly installed on the front of the base 1, and the baffle 11 is located in front of the second hinge shaft 5. The baffle 11 can cover the structure between the top seat 3 and the base 1 from the front; the bottom of the top seat 3 is provided with two shielding parts 31 arranged on the left and right, and the base 1 is between the two shielding parts 31. The shielding part 31 can cover the structure between the top seat 3 and the base 1 from both left and right directions.

In this embodiment, the second adjustment seat 66 and the second mounting seat 663 are integrally formed, and in order to further reduce the weight of the chassis, the integrally formed second adjustment seat 66 and the second mounting seat 66 are made of hard plastic such as nylon, and the base 1 and the top seat 3 are also made of hard plastic.

In this embodiment, a mounting hole 16 for mounting the gas rod is provided on the base 1 , and a lever 7 for opening and closing the gas rod is also installed on the base 1 .

In this embodiment, as shown in FIGS. 2-4 , the tailstock 2 further includes a second connecting plate 21 and a third connecting plate 23, the two first connecting plates 22 are fixedly connected by the second connecting plate 21 and the third connecting plate 23, the second connecting plate 21 is located at the rear side of the base 1, and the third connecting plate 23 is located above the second adjustment seat 66. In this way, the overall rigidity and overall stability can be increased.

A chair comprises the above-mentioned adjustable chassis, and further comprises chair feet mounted on the base, a chair seat on the top seat and a chair back on the tail seat.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, substitute and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

An adjustable chassis comprises a base (1), a top base (3), a tail base (2) and a tension spring (65), wherein the base (1) and the tail base (2) are hinged via a first hinge shaft (4), and the top base (3) and the tail base (2) are hinged via a second hinge shaft (5), and the tail base (2) comprises two left and right first connecting plates (22), the two first connecting plates (22) of the tail base (2) are hinged to the base (1) via the first hinge shaft (4), and the front portions of the two first connecting plates (22) of the tail base (2) are connected to the base (1) via the first hinge shaft (4). The bottom of the first adjusting seat (62) is hinged to the base (1) through a third hinge shaft (61), and the top of the first adjusting seat (62) is hinged to the top seat (3) through a fourth hinge shaft (63), the fourth hinge shaft (63) is located on the rear side of the second hinge shaft (5), one end of the tension spring (65) is connected to the fourth hinge shaft (63), and the other end of the tension spring (65) is connected to the base (1) through an adjusting device.
An adjustable chassis according to claim 1 is characterized in that it also includes a first mounting seat (64), the top of the first adjustment seat (62) is hinged to the first mounting seat (64) through a fourth hinge shaft (63), the first adjustment seat (62) is hinged to the top seat (3) through the fourth hinge shaft (63), one end of the tension spring (65) is connected to the first mounting seat (64), and the other end of the tension spring (65) is connected to the front part of the base (1) through an adjustment device; the adjustment device includes a second adjustment seat (66), a second mounting seat (663) is fixed on the second adjustment seat (66), two ends of the tension spring (65) are respectively connected to the first mounting seat (64) and the second mounting seat (663), an adjustment screw (68) is threadedly connected to the second adjustment seat (66), and the adjustment screw (68) is installed on the base (1) and can rotate.
An adjustable chassis according to claim 2 is characterized in that a bayonet (664) is provided on the second adjustment seat (66), a nut (67) is installed in the bayonet (664), and an adjusting screw (68) passes through the nut (67) and is threadedly connected; when the adjusting screw (68) rotates, the nut (67) can drive the second adjustment seat (66) to move along the axis of the adjusting screw (68).
An adjustable chassis according to claim 3, characterized in that a handle (69) is fixed to one end of the adjusting screw (68), a pin (667) is radially fixedly installed at the other end of the adjusting screw (68), and the handle (69) is located outside the base.
An adjustable chassis according to claim 2 is characterized in that there are two tension springs (65) and they are symmetrically arranged on the left and right, there are two first mounting seats (64) and they are symmetrically arranged on the left and right, and there are two second mounting seats (663) and they are symmetrically arranged on the left and right.
An adjustable chassis according to claim 2 is characterized in that the outer side surface of the first mounting seat (64) and the outer side surface of the second mounting seat (663) both have a spiral fixing groove, and the two ends of the tension spring (65) are respectively clamped in the fixing groove of the first mounting seat (64) and the fixing groove of the second mounting seat (663).
An adjustable chassis according to claim 2, characterized in that a guide portion (17) is protruded from the base (1) for preventing the second adjustment seat (66) from lateral movement, and a guide groove (665) opening downward is provided at the bottom of the second adjustment seat (66), and the guide portion (17) of the base (1) is inserted from bottom to top into the guide groove (665) at the bottom of the second adjustment seat (66).
An adjustable chassis according to claim 2, characterized in that two positioning grooves (14) opening upward are also provided on the chassis (1), the positioning grooves (14) extending backward through the base (1), and the two first connecting plates (22) of the tail stock (2) are respectively inserted into the two positioning grooves (14) and hinged to the base (1) through the first hinge shaft (4).
The adjustable chassis according to claim 1 is characterized in that the base (1) and the top seat (3) are made of plastic.
A chair, characterized by comprising an adjustable chassis according to any one of claims 1 to 9.