CN111214029A - Seat with swing function - Google Patents

Abstract

The invention relates to the field of seats, in particular to a seat with a swinging function. The invention provides a seat with a swinging function, which comprises a seat plate, a support rod and a base, wherein the bottom end of the support rod is a first rigid sleeve which is fixedly spliced through taper fit with the base, a filling piece is sleeved on the upper part of the first rigid sleeve, a flange is arranged at the top end of the filling piece, a vertical friction groove is formed in the side wall of the first rigid sleeve, a through hole is formed in the center of the first rigid sleeve, a built-in rigid piece is sleeved in the through hole, and the top end of the built-in rigid piece is fixedly spliced through taper fit with an elastic bearing piece.

Description

Seat with swing function

Technical Field

The invention relates to the field of seats, in particular to a seat with a swinging function.

Background

People can damage the muscles of the waist and the back when sitting for a long time, easily cause a series of occupational diseases such as lumbar muscle strain, back pain, cervical spondylitis and the like, and people who sit for a long time need a seat which is more in line with ergonomics and is helpful for users to take more beneficial sitting postures, so that the users can adjust the sitting postures at any time or exercise to achieve the purpose of exercising the muscles of the waist and the back. For persons who must stand for a long time to work (such as professional service staff, hairdressers and the like), possibly causing occupational diseases such as atherosclerosis and varicose veins, a seat with a high sitting posture, free inclination and recovery and following action and needing to adjust the sitting posture is also needed.

The patent document DE2314717 discloses a rocking chair structure, in which the upper and lower ends of the supporting rod are both provided with a spring and a hemisphere to cooperate with each other to realize free tilting of the chair seat plate, the spring is provided with an elastic support, and the spring and the hemisphere are in relative swinging and rigid friction contact. This structure has the following problems: 1. a free inclined swinging structure is arranged between the support rod and the bottom foot, so that large-range inclined swinging can be realized, but the swinging distance of the seat board is large, the bottom foot cannot be firmly fixed with the ground, the chair is easy to topple due to overlarge swinging, and the stability is poor; 2. the swinging position is at the contact position of the pressure spring and the hemisphere, and the pressure spring is in rigid friction contact with the surface of the hemisphere, so that the swinging is difficult, larger noise can be generated in the swinging process, the surface of the hemisphere is easy to deform due to long-time extrusion of the pressure spring, the swinging difficulty is increased, parts are easy to damage and lose efficacy, the service life is greatly reduced, and the swinging device is particularly serious when the weight of a user is larger; 3. similarly, the seat plate cannot swing to stay at a required position and cannot quickly return to an initial sitting position due to rigid friction contact between the pressure spring and the hemispheroid and inevitable axial distortion of the spring; 4. when the seat plate freely swings obliquely, the whole spring must be compressed along the axis of the spring to provide a hemispherical swing space, so that a positive pressure which is large enough is applied to the pressure spring in an oblique sitting posture state of a user, otherwise, the pressure spring cannot swing obliquely or reset forcibly, normal use is influenced, inconvenience and poor safety are caused, and the difficulty in selecting and debugging the spring is greatly increased; 5. the swinging device with the structure of matching the pressure spring and the hemispheroid is complex in structure, the swinging device can be installed only by correspondingly changing the structure of the chair, the application range is small, and the universality is poor.

The patent document of publication No. CN205597562U discloses a support member of a stand-up seat, a seat portion of which is mounted on an upper end of a swing lever, and the height of which can be freely adjusted by adjusting the height of the swing lever to improve the applicability of the stand-up seat. The free inclination and the reset of the upright seat are realized by the cooperation of an elastic reset component at the lower part of the swinging rod and the swinging rod mounting seat. When the installation is carried out, the elastic reset component is firstly assembled, the upper side and the lower side of the upper flange of the swinging rod are respectively provided with the elastic rubber rings, then the swinging rod which completes the installation steps is inserted into the installation cavity of the swinging rod installation seat, and at the moment, the rotating part of the sleeving part is positioned in the cavity. The inner wall of the cavity and the cambered surface of the rotating part are smooth surfaces, and the lower end of the oscillating rod can freely incline or rotate around the inner side wall of the cavity. The spacing collar is fixed on the upper part of the swinging rod, and the elastic reset component is pressed in the installation cavity. When the swinging rod is inclined by external force, one side of the elastic rubber ring below the flange extrudes the bottom of the mounting cavity, one side of the elastic rubber ring above the flange extrudes the limiting ring, and when the external force is removed, the extrusion force of the elastic rubber ring drives the swinging rod to recover to the initial position. Therefore, it can be seen that relative swing is realized through the cooperation of the rotating part installed on the lower end socket piece of the swing rod and the installation groove cambered surface of the installation seat of the swing rod, the rotating part and the installation groove are in rigid support and rigid friction contact, and the elastic rubber ring only provides restoring force. This structure has the following problems: 1. a free inclined structure is arranged between the support rod (the oscillating rod) and the bottom foot (the mounting seat), so that although the large-range inclined oscillation can be realized, the oscillating distance of the seat plate is large, the bottom foot and the ground cannot be firmly fixed, the chair is easy to topple due to too large oscillation, and the stability is poor; 2. the cambered surfaces of the rotating part and the mounting groove are in rigid support and rigid frictional contact, so that the swinging is difficult, large noise can be generated in the swinging process, the surfaces of the rotating part and the mounting groove are easy to deform and wear due to long-time extrusion and friction, the swinging difficulty is increased, parts are easy to damage and lose efficacy, the service life is greatly reduced, and the swinging is particularly serious when the weight of a user is large; 3. the whole swing device is complex in structure and difficult to debug, the swing device can be installed only by correspondingly changing the structure of the chair, the application range is small, and the universality is poor.

Patent documents with publication numbers CN205795340U and CN205831505U disclose a chair capable of tilting and swinging, which comprises chair legs, a seat cushion and a compressed air rod connected with the chair legs and the seat cushion, wherein a taper sleeve is arranged at the bottom of the compressed air rod, the taper sleeve is arranged in an inner cavity of the chair legs, the outer side of the taper sleeve is wrapped by a soft sleeve, the compressed air rod swings under the action of the soft sleeve and the wall of the inner cavity of the chair legs, and the compressed air rod can drive the seat cushion to rotate in a 360-degree tilting manner. It can thus be seen that it provides elastic support and restoring forces through the flexible sleeve. This structure has the following problems: 1. a free inclined structure is arranged between the supporting rod and the bottom foot, so that large-range inclined swinging can be realized, but the swinging distance of the seat board is large, the bottom foot cannot be firmly fixed with the ground, the chair is easy to topple due to overlarge swinging, and the stability is poor; 2. the inner wall and the outer wall of the soft sleeve are provided with gaps, the soft sleeve does not have any rigid support and deformation limitation, the weight and the swing of a user and the upper part of the chair completely depend on the connection part between the inner wall and the outer wall to provide support, the deformation which cannot be recovered is easily generated, very high requirements are provided for the material selection of the soft sleeve, the components are easy to damage and lose efficacy, the service life is greatly reduced, and the soft sleeve is particularly serious when the weight of the user is larger; 3. the whole swing device is complex in structure and difficult to debug, the swing device can be installed only by correspondingly changing the structure of the chair, the application range is small, and the universality is poor.

The patent document TW1578939B discloses a tiltable working chair, whose support bar fixes a sleeve section and a connecting piece at the lower end, the underside of the connecting piece being connected to the base by means of an elastic bearing element, so that it can be seen that it provides both an elastic bearing support force and an elastic restoring force of the tilting pendulum by means of the elastic bearing element. This structure has the following problems: 1. a free inclined structure is arranged between the supporting rod and the bottom foot, so that large-range inclined swinging can be realized, but the swinging distance of the seat board is large, the bottom foot cannot be firmly fixed with the ground, the chair is easy to topple due to overlarge swinging, and the stability is poor; 2. the elastic bearing part is annular, although the upper surface and the lower surface are limited, the inner and outer circumferential surfaces of the elastic bearing part are not limited (in fact, the limitation cannot be carried out, and the swinging is difficult), when the chair bears the load for a long time and/or bears the load heavier, the elastic bearing part is integrally and uniformly borne, the inner and outer circumferential surfaces of the elastic bearing part are not controlled in deformation without limitation, the deformation which cannot be recovered is easily generated, and the free inclined swinging cannot be realized, so that the very high requirements on material selection are provided, the components are easy to damage and lose efficacy, the service life is greatly reduced, and the weight is particularly serious when the weight of a; 3. the whole swing device is complex in structure and difficult to debug, the swing device can be installed only by correspondingly changing the structure of the chair, the application range is small, and the universality is poor.

How to solve the problems in the prior art is the innovative point of the present invention.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a piece of seating furniture with a swinging function, which has large swinging moment and convenient replacement of an elastic bearing piece, and the specific technical scheme is as follows:

the utility model provides a thing to sit on with sway function comprises bedplate (1), bracing piece (2) and base (3), its characterized in that, bracing piece (2) bottom be with base (3) taper fit grafting fixed first rigidity sleeve (21), insert in the first rigidity sleeve and establish and be fixed with packing piece (22) and built-in rigidity piece (23), the central point of packing piece (22) is through-hole (223), set up built-in rigidity piece (23) in through-hole (223), the top cover of built-in rigidity piece (23) is equipped with elastic support piece (24), and the central point of elastic support piece (24) has seted up the tapering hole, the tapering downthehole rigidity cover (242) that is fixed with, rigidity cover (242) and built-in rigidity piece (23) top degree cooperation grafting are fixed, elastic support piece (24) overcoat is equipped with second rigidity sleeve (25), the lateral wall of elastic support piece (24) with the inner wall of second rigidity sleeve (25) offsets, second rigidity sleeve (25) internal fixation has rigidity gasket (252), the top that the elastic bearing held piece (24) offsets with rigidity gasket (252), second rigidity sleeve (25) top cover is equipped with connecting rod (26), connecting rod (26) bottom be grafting portion and with second rigidity sleeve (25) taper fit grafting is fixed, gas pole (27) are installed to connecting rod (26) top, the gas pole with bedplate (1) are pegged graft fixedly.

Preferably, the top end of the plug (22) is provided with a flange (221), and the side wall of the plug is provided with a vertical friction rib (222). The filling piece is firmly inserted into the first rigid sleeve, and the installation is convenient.

Preferably, the outer side wall of the elastic bearing piece (24) is provided with an annular groove (241). Thus, the seat has large swing angle and proper restoring force.

Preferably, the bottom end of the second rigid sleeve (25) is turned inwards to form a platform part (251) and is abutted against the bottom of the elastic bearing piece (24). Therefore, the second rigid sleeve and the elastic bearing part can be prevented from being separated, the connection is reliable, and the swing is stable.

Preferably, a tenon (231) is arranged at the bottom end of the built-in rigid part (23), the tenon (231) extends out of a through hole formed in the center of the bottom platform part of the first rigid sleeve (21), a flange is arranged at the bottom end of the tenon (231), the flange is connected with an elastic fixing piece (232) in a clamping mode, a bayonet is arranged in the middle of the elastic fixing piece (232), the shape of the bayonet is matched with that of the flange at the bottom end of the tenon (231), a metal gasket is arranged between the elastic fixing piece (232) and the bottom platform part of the first rigid sleeve (21), and a rubber gasket (233) is arranged between the built-in rigid part (23) and the bottom platform part of the first rigid sleeve (21). Thus, the installation is convenient, the fixation is reliable, and the disassembly and the assembly are convenient.

Preferably, the base (3) is provided with a cylindrical jack at the center, the side wall (31) of the cylindrical jack is a rigid member, an annular reinforcing rib (311) is fixedly arranged on the side wall (31) of the cylindrical jack at the outer part, and the periphery of the reinforcing rib (311) is fixedly connected with the inner wall of the upper structure of the base. The supporting structure is firm and reliable, and the manufacturing cost is low.

Preferably, the seat plate (1) comprises an upper component (11), a lower component (12) and a bottom component (13), a containing hole is formed in the center of the bottom component (13), a connecting rod (26) and an air rod (27) are inserted into the containing hole, the bottom component is buckled with the lower component (12) through a semicircular tenon (131), a control key (121) is arranged in the lower component (12), a protruding portion is arranged in the middle of the control key (121), a ball head (122) is arranged at the top end of the protruding portion, the ball head is sleeved with a hemispherical empty groove formed in the lower component (12), and a right angle of the tail end of the control key (121) is turned downwards and abuts against a control switch at the top of the air rod (27). Therefore, the control key takes the ball head part as a rotation center to form a lever structure, and the tail end in the control key can press the control switch at the top of the air rod to release the air rod to realize lifting by pressing the exposed key end.

Preferably, the diameter of the upper part of the second rigid sleeve (25) is smaller than that of the lower part, the connecting part has a taper, a rigid gasket (252) is arranged in the connecting part, and the taper of the outer side wall of the rigid gasket (252) is the same as that of the connecting part. Thus, the structure is simple and the installation is convenient.

By adopting the technical scheme, the invention realizes convenient assembly and disassembly, convenient replacement of wearing parts, and better use experience because a larger torsion moment can be obtained when the swing function is used.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of a swing state structure according to the present invention;

FIG. 3 is a cross-sectional view of the base and the support rod of the present invention;

FIG. 4 is an exploded view of the base and support rods of the present invention;

FIG. 5 is an enlarged view taken at A of FIG. 3 according to the present invention;

FIG. 6 is a cross-sectional view of the present invention in a rocking state;

fig. 7 is a sectional view of the seat plate and the support rod of the present invention.

The reference numbers in the drawings are as follows:

1 seat plate, 2 support rods, 3 bases, 21 first rigid sleeve, 22 packing piece, 221 flange, 222 vertical friction rib, 223 through hole, 23 built-in rigid piece, 24 elastic bearing piece, 241 annular groove, 242 rigid sleeve, 25 second rigid sleeve, 251 platform part, 252 rigid gasket, 26 connecting rod, 27 air rod, 231 tenon, 232 elastic fixing piece, 233 rubber gasket, 31 cylindrical jack side wall, 311 annular reinforcing rib, 11 upper assembly, 12 lower assembly, 13 bottom assembly, 131 semicircular tenon, 121 control key and 122 ball head.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be considered as limiting the present invention.

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

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

Fig. 1 to 5 show a sitting tool with a swing function, which comprises a seat plate 1, a support rod 2 and a base 3, wherein the bottom end of the support rod 2 is a first rigid sleeve 21 which is fixedly inserted in a taper fit manner with the base 3, the upper part of the first rigid sleeve is sleeved with a plug 22, the top end of the plug 22 is provided with a flange 221, the side wall of the support rod is provided with a vertical friction convex edge 222, the center position of the vertical friction convex edge is a through hole 223, a built-in rigid member 23 is sleeved in the through hole 223, the top end of the built-in rigid member 23 is fixedly inserted in a taper fit manner with an elastic bearing member 24, the side wall of the elastic bearing member 24 starts to be provided with an annular groove 241, the center position of the annular groove is provided with a taper hole matched with the insertion portion, the inner wall of the taper hole is fixedly provided with a rigid sleeve 242, the, the lateral wall that the elastic carrier 24 held with the inner wall of second rigid sleeve 25 offsets, second rigid sleeve 25 bottom turn over inwards and turn over and constitute platform portion 251 and with elastic carrier 24 bottom offsets, second rigid sleeve 25 top cover is equipped with connecting rod 26, the connecting rod 26 bottom be grafting portion and with second rigid sleeve 25 taper fit grafting is fixed, the connecting rod 26 top is equipped with central groove, it has gas pole (27) to peg graft in the central groove, the gas pole with bedplate 1 is pegged graft fixedly. The swinging device is arranged on the base accessory, so that the swinging moment is lengthened, the swinging effect which is the same as that of the bearing piece made of a softer material can be obtained by using the elastic bearing piece with higher strength, and secondly, the supporting rod is convenient to integrally insert, pull and disassemble by arranging the filling piece, and the processing difficulty is also reduced. Built-in rigidity piece 23 bottom is equipped with tenon 231, the through-hole that first rigidity sleeve 21 bottom platform portion center was seted up is visited on tenon 231 top, tenon 231 bottom is equipped with the flange, flange and elastic fixing piece 232 joint, elastic fixing piece 232 intermediate position is equipped with the bayonet socket, its shape with the flange phase-match of tenon 231 bottom, elastic fixing piece 232 with be equipped with the metal gasket between the platform portion of first rigidity sleeve 21 bottom, built-in rigidity piece 23 with be equipped with rubber gasket 233 between the platform portion of first rigidity sleeve 21 bottom. Through twisting the elastic fixing piece, can be convenient make built-in rigidity piece break away from with first rigidity sleeve, when conveniently dismantling and changing spare part, the existence of rubber gasket can be so that to sit and feel more comfortable. 3 central point on base is upper and lower open-ended cylindricality jack, cylindricality jack lateral wall 31 is the rigidity piece, cylindricality jack lateral wall 31 external fixation is equipped with annular strengthening rib 311, strengthening rib 311 periphery with the inner wall fixed connection of base superstructure. Because the moment increases, the torsion that base centre bore will also increase, and ordinary base certainly can not bear this torsion so, inventor has solved this problem through strengthening the lateral wall structure and setting up the strengthening rib.

Fig. 1 to 7 show a thing to sit on with sway function, bedplate 1 comprises upper assembly 11, lower part subassembly 12 and bottom subassembly 13, bottom subassembly 13 internal center puts and is equipped with the accommodation hole, the accommodation hole endotheca is equipped with connecting rod 26, the bottom subassembly passes through semi-circular tenon 131 and lower part subassembly 12 lock joint, be equipped with control button 121 in the lower part subassembly 12, control button 121 intermediate position is equipped with the bellying, the bellying top is equipped with bulb 122, the bulb with the inside hemisphere dead slot that sets up of lower part subassembly 12 offsets and cup joints, control button 121 tail end right angle turns over downwards, and its top with the control switch at gas pole 27 top offsets. The control gas rod has simple structure and reliable action, and each component is of a buckling structure, so that the control gas rod is easy to disassemble while being easy for standardized large-scale production. The diameter of the upper part of the second rigid sleeve 25 is smaller than that of the lower part, the joint has taper, a rigid gasket 252 is arranged in the joint, and the taper of the outer side wall of the rigid gasket 252 is the same as that of the joint. Such a configuration can accommodate greater tolerances.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (8)

1. The utility model provides a thing to sit on with sway function comprises bedplate (1), bracing piece (2) and base (3), its characterized in that, bracing piece (2) bottom be with base (3) taper fit grafting fixed first rigidity sleeve (21), insert in the first rigidity sleeve and establish and be fixed with packing piece (22) and built-in rigidity piece (23), the central point of packing piece (22) is through-hole (223), set up built-in rigidity piece (23) in through-hole (223), the top cover of built-in rigidity piece (23) is equipped with elastic bearing spare (24), and the central point of elastic bearing spare (24) has seted up the tapering hole, the downthehole rigidity cover (242) that is fixed with of tapering, rigidity cover (242) and built-in rigidity piece (23) top degree cooperation grafting are fixed, elastic bearing spare (24) overcoat is equipped with second rigidity sleeve (25), the utility model discloses a bedplate, including base plate (1), elastic bearing spare (24), connecting rod (26) bottom, connecting rod (26) taper fit grafting is fixed, the lateral wall that elastic bearing spare (24) with the inner wall of second rigidity sleeve (25) offsets, second rigidity sleeve (25) internal fixation has rigidity gasket (252), the top that elastic bearing spare (24) supported offsets with rigidity gasket (252), second rigidity sleeve (25) top cover is equipped with connecting rod (26), connecting rod (26) bottom for grafting portion and with second rigidity sleeve (25) taper fit grafting is fixed, gas pole (27) are installed on connecting rod (26) top, the gas pole with bedplate (1) is pegged graft fixedly.

2. A seat with rocking function according to claim 1, characterized in that the top end of the packing (22) is provided with a flange (221) and the side wall with vertical friction ridges (222).

3. A seat with a rocking function as claimed in claim 1, wherein the resilient carrier (24) has an annular groove (241) on its outer side.

4. A seat with rocking function according to claim 1, characterized in that the bottom end of the second rigid sleeve (25) is turned inwards to form a platform (251) and abuts against the bottom of the elastic support (24).

5. The seat with the rocking function as claimed in claim 1, wherein a tenon (231) is provided at the bottom end of the built-in rigid member (23), the tenon (231) protrudes out of a through hole formed in the center of the bottom platform of the first rigid sleeve (21), a flange is provided at the bottom end of the tenon (231), the flange is connected with an elastic fixing piece (232) in a clamping manner, a bayonet is provided at the middle position of the elastic fixing piece (232), the shape of the bayonet is matched with that of the flange at the bottom end of the tenon (231), a metal gasket is provided between the elastic fixing piece (232) and the bottom platform of the first rigid sleeve (21), and a rubber gasket (233) is provided between the built-in rigid member (23) and the bottom platform of the first rigid sleeve (21).

6. A seat with a rocking function according to claim 1, wherein the base (3) is a cylindrical socket at the center, the cylindrical socket side wall (31) is a rigid member, an annular reinforcing rib (311) is fixedly arranged on the cylindrical socket side wall (31) at the outside, and the periphery of the reinforcing rib (311) is fixedly connected with the inner wall of the upper structure of the base.

7. The seat with the swing function as claimed in claim 1, wherein the seat plate (1) is composed of an upper component (11), a lower component (12) and a bottom component (13), a receiving hole is formed in the center of the bottom component (13), a connecting rod (26) and an air rod (27) are inserted into the receiving hole, the bottom component is fastened with the lower component (12) through a semicircular tenon (131), a control button (121) is arranged in the lower component (12), a boss is arranged in the middle of the control button (121), a ball head (122) is arranged at the top end of the boss, the ball head is sleeved with a hemispherical empty slot formed in the lower component (12), and the right angle of the tail end of the control button (121) is turned downwards and abuts against a control switch at the top of the air rod (27).

8. A seat with rocking function according to claim 1, wherein the second rigid sleeve (25) has a smaller diameter at the upper part than at the lower part, and the joint has a taper, and a rigid gasket (252) is provided in the joint, and the taper of the outer side wall of the rigid gasket (252) is the same as the taper of the joint.

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