Chair

Abstract

To provide a chair having a preferable configuration in which a seat tray fitted to a gas spring becomes difficult to come off to the gas spring.SOLUTION: A chair is provided in which a leg A includes a leg base 1, and a leg strut 2 being set up to the leg base 1 and including a gas spring G being elastic in the vertical direction. A seat C includes a seat tray 4 having a first external fitting part P that can be fitted in a top internally fitted part M provided at an upper part of the gas spring G. A connection-strengthening screw E interposed between the top internally fitted part M and the seat tray 4, and being connection-strengthening means capable of being engaged to both sides of the top internally fitted part M and the seat tray 4 is provided.SELECTED DRAWING: Figure 14

Description

Technical Field

[0001] The present invention relates to a chair.

Background Art

[0002] Conventionally, a chair has been known that can be seated on a seat even when the leg support is inclined with respect to the floor surface (see, for example, Patent Document 1). This type of chair is easily movable to an appropriate position by the user. In many cases, the chair is carried by the user with the seat at a relatively high position from the floor surface being gripped and the lower end of the leg being lifted from the floor surface.

[0003] However, the seat is usually simply externally fitted to the upper end of the gas spring constituting the leg support, and there has been a concern that the seat may come off from the leg support in a scene where the user grips and carries the seat.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made paying attention to the above circumstances, and at least provides a chair having a preferable configuration in which a seat receiver fitted to a gas spring is difficult to come off from the gas spring.

Means for Solving the Problems

[0006] That is, the present invention has the following configuration.

[0007] The invention according to claim 1 is a chair comprising a seat and legs capable of supporting the seat so as to be vertically movable up and down, wherein the legs comprise a leg base and a leg support column provided upright on the leg base and having a gas spring capable of expanding and contracting in the vertical direction, the seat comprises a seat receiver having a first outer fitting portion capable of fitting into an upper inner fitting portion provided at the upper portion of the gas spring, and connecting and strengthening means is provided between the upper inner fitting portion and the seat receiver and capable of engaging with both the upper inner fitting portion and the seat receiver. It includes a cylinder extending in the vertical direction and a piston rod having the upper fitting portion and supported so as to be vertically movable with respect to the cylinder. The leg base includes a leg base body having a second outer fitting portion into which a lower fitting portion provided at the lower end of the cylinder can be fitted, and a leg base cover attached to the upper surface side of the leg base body. The leg support includes a cylinder cover covering the cylinder. The leg base cover and the cylinder cover are integrally formed. The cylinder cover is provided with a detachment restricting portion disposed above the cylinder and capable of restricting the gas spring from detaching from the cylinder cover. It is a chair.

[0008] The invention according to claim 2 is a chair comprising a seat and legs capable of supporting the seat so as to be vertically movable up and down, wherein the legs comprise a leg base and a leg support column provided upright on the leg base and having a gas spring capable of expanding and contracting in the vertical direction, the seat comprises a seat receiver having a first outer fitting portion capable of fitting into an upper inner fitting portion provided at the upper portion of the gas spring, and connecting and strengthening means is provided between the upper inner fitting portion and the First outer fitting portion intervening therebetween and capable of engaging with both the upper inner fitting portion and the First outer fitting portion seat receiver. It is as follows: The connecting and strengthening means is a connecting and strengthening screw screwed between the upper inner fitting portion and the First outer fitting portion seat receiver. The connecting reinforcement screw is screwed into a notched nut portion provided in the first outer fitting portion. The notched nut portion has a shape notched so that a part of the thread flank of the screwed connecting reinforcement screw can contact the upper fitting portion. It is a chair.

[0009] The invention according to claim 3 is The connecting reinforcement means is a connecting reinforcement screw screwed between the upper fitting portion and the first outer fitting portion. Claim 1 the chair described.

[0010] The invention according to claim 4 is the chair according to claim, wherein the cylinder cover has a substantially cylindrical shape and a cylinder cover body integrally connected to the leg base cover at the lower end, and an inwardly extending flange integrally extending inward from the upper portion of the cylinder cover body and constituting the detachment restricting portion. 1 the chair described.

[0011] The invention according to claim 5 is the chair according to claim 1, 2, 3 or 4, wherein the leg base is integrally connected to the leg support and has a substantially curved surface that can contact the floor surface at the bottom.

[0012] The invention according to claim 6 is the chair according to claim 1, 2, 3, 4 or 5, which is provided with a lumbar support that can be attached to the seat and contact the lumbar region of the seated person, and this lumbar support has a part that can be grasped by the user when moving the entire chair.

[0013] The invention according to claim 7 is the chair according to claim 1, 2, 3, 4, 5 or 6, which is provided with a leg support cover in a cylindrical shape with the leg support disposed inside, and the upper end thereof is supported by the seat receiver.

Advantages of the Invention

[0014] As described above, according to the present invention, it is possible to provide a chair having a suitable configuration in which at least the seat receiver fitted to the gas spring is difficult to come off from the gas spring.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Mode for Carrying Out the Invention

[0016] Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 15.

[0017] This embodiment is applied to a chair (hereinafter simply referred to as "chair") which is preferably used in an office or the like and is also called a "stool".

[0018] The chair shown in this embodiment is configured such that not only can it take an overall state substantially perpendicular to the floor surface R, but also a seated person can sit even when it is tilted with respect to the floor surface R. In other words, the chair is such that the leg support 2 constituting the leg A can take a posture tilted with respect to the floor surface R, and even when the leg support 2 is in a posture tilted with respect to the floor surface R, a seated person can sit on the seat C.

[0019] The chair includes legs A that can stand up tiltably with respect to the floor surface R, a seat C supported by the legs A, a leg support cover B whose upper end is supported by the seat C, and a lumbar support F attached to the seat C and capable of abutting against the waist of the seated person.

[0020] A connection strengthening screw E, which is a connection strengthening means for strengthening the degree of connection between the leg A and the seat C, is provided between the leg A and the seat C.

[0021] Hereinafter, each component of the chair will be described in detail.

[0022] <<Leg A>> The leg A can support the seat C so that it can move up and down. The leg A includes a leg base 1 with a grounding surface S facing the floor surface R being substantially curved, and a leg support 2 having a gas spring G that stands upright with respect to the leg base 1 and can expand and contract in the vertical direction.

[0023] The leg A is weighted by a weight such as a weight (not shown) so that it can stand substantially vertically with respect to the floor surface R in a no-load state where the seated person is not seated on the seat C.

[0024] <leg base 1> The leg base 1 is integrally connected to the lower part of the leg support 2. The leg base 1 has a substantially curved shape such that the grounding surface S, which is the lower surface, can contact the floor surface R.

[0025] The leg base 1 includes a leg base body 11 that is an outer fitting part into which an inner fitting part K provided on the cylinder g1 of the gas spring G can be fitted, and a leg base cover 12 attached to the upper surface side of the leg base body 11.

[0026] [leg base body 11] The leg base body 11 has a grounding surface S with a substantially partial spherical surface shape on the lower surface. The leg base body 11 includes a base shell T that is substantially disk-shaped as a whole with a plurality of reinforcing ribs standing upright on the upper surface side of the member forming the grounding surface, and a second outer fitting part J that is substantially cylindrical and stands upright at the center of the base shell T.

[0027] [leg base cover 12] The leg base cover 12 has a shape that covers the upper part of the leg base body 11, that is, the upper surface side of the base shell T and the outer peripheral surface of the upper part of the second outer fitting part J.

[0028] In this embodiment, the leg base cover 12 is integrally formed with a cylinder cover I that covers the cylinder g1 of the leg support 2. That is, this chair is provided with a cover body that is an integrally molded product of synthetic resin of the leg base cover 12 and the cylinder cover I. In other words, the chair is provided with a cover body that covers the upper part of the leg base main body 11 and the cylinder g1 of the gas spring G.

[0029] On the inner surface side of the leg base cover 12, a nut portion n1 exposed downward is provided. The leg base cover 12 is attached to the upper surface side of the leg base main body 11 by screwing a screw v1 inserted through a screw insertion hole h1 provided in the leg base main body 11 to the nut portion n1.

[0030] <leg support 2> The leg support 2 extends in the vertical direction. The upper end portion of the leg support 2 is connected to the seat C.

[0031] The leg support 2 includes a gas spring G that stands upright with respect to the leg base 1 and is vertically expandable and contractible, and a cylinder cover I that covers the cylinder g1 that constitutes the lower part of the gas spring G.

[0032] As described above, the cylinder cover I is integrally formed with the leg base cover 12.

[0033] [gas spring G] The gas spring G includes a cylinder g1 that extends in the vertical direction, and a piston rod g2 that has an upper fitting portion M that is a fitting portion fitted into the seat receiver 4 at the upper end portion and is supported so as to be vertically movable with respect to the cylinder g1.

[0034] At the lower end portion of the cylinder g1, a lower fitting portion K that fits into a second outer fitting portion J provided in the leg base main body 11 is provided. The lower fitting portion K has a tapered shape in which the outer surface gradually approaches the axis toward the lower side.

[0035] At the upper end of the piston rod g2, there is an upper fitting portion M that fits into the first outer fitting portion P provided on the seat 4. The upper fitting portion M has a tapered shape in which the outer surface gradually approaches the axis upward.

[0036] Note that at the tip of the piston rod g2, there is a lock release button g3 for releasing the expansion and contraction lock of the gas spring G. The lock release button g3 is operated by an operation lever D supported by the seat C.

[0037] Note that since the gas spring G has a known configuration, a detailed description thereof is omitted.

[0038] [Cylinder Cover I] The cylinder cover I includes a cylinder cover main body i1 having a substantially cylindrical shape and integrally connected to the leg base cover 12 at the lower end, and an inwardly extending flange i2 that forms a detachment restricting portion and extends integrally inward from the upper end of the cylinder cover main body i1.

[0039] The inwardly extending flange i2, which is a detachment restricting portion, is disposed so as to cover the upper part of the cylinder g1, that is, above the upper end of the cylinder g1, and can restrict the detachment of the gas spring G from the cylinder cover I.

[0040] That is, the cylinder cover I provided with the inwardly extending flange i2 is integrally connected to the leg base cover 12.

[0041] And the leg base cover 12 is fixed to the leg base main body 11 by a screw v1. That is, the cover body (cylinder cover I and leg base cover 12) is configured not to detach from the leg base main body 11.

[0042] Therefore, even if the lower fitting portion K of the gas spring G comes off from the second outer fitting portion J provided on the leg base main body 11, the inwardly extending flange i2 can restrict the cylinder g1 from coming out.

[0043] In other words, with the configuration of leg A in this embodiment, even when the lower fitting portion K of gas spring G comes off from the second outer fitting portion J of leg base 1, it is difficult for gas spring G to separate from cylinder cover I.

[0044] <<Seat C>> Seat C includes a seat body 3 having a seating surface and a seat receiver 4 also referred to as an outer shell that supports seat body 3.

[0045] In this embodiment, the front-rear dimension w1 of seat C is set shorter than the left-right dimension w2 of seat C. Seat C has a shape approximating a substantially horizontally long rectangle in plan view. That is, seat C has a form in which four corner portions that appear as a horizontally long rectangle in plan view are rounded into partial arcs.

[0046] As shown in FIG. 6, seat C is set such that the width dimension w1 in the left-right direction in plan view is more than twice as long as the width dimension w2 in the front-rear direction.

[0047] Since seat C is configured to be swingable with respect to floor surface R based on the form of leg A, it is basically desirable that the dimension in the horizontal direction is not set too large. On the other hand, seat C preferably has a lateral width dimension that can appropriately support the buttocks of the seated person. In the chair of this embodiment, the width dimension w2 in the left-right direction of seat C is set within the range of 2 to 2.5 times the width dimension w1 in the front-rear direction so as to preferably satisfy these requirements.

[0048] <Seat body 3> Seat body 3 includes a synthetic resin-made support member 32 also referred to as an inner shell, a seat cushion 31 placed on support member 32, and a seat upholstery (not shown) that covers the peripheral portions of seat cushion 31 and support member 32.

[0049] Seat body 3 as a whole has a shape extending in the left-right direction.

[0050] <Seat receiver 4> The seat receiver 4 has a shell shape with a bottom surface forming an externally exposed surface that can be visually recognized by the user or the like, and a plurality of reinforcing ribs are erected on the upper surface side. As a whole, the seat receiver 4 has a shape extending in the left - right direction. On the upper surface side of the seat receiver 4, a support member 32 that constitutes the seat body 3 is configured to be attached by attachment means (not shown).

[0051] The seat receiver 4 has a first outer fitting portion P that can be fitted into an upper inner fitting portion M provided on the upper part of the gas spring G at substantially the central portions in the left - right direction and the front - rear direction. The first outer fitting portion P is mainly composed of a substantially cylindrical portion that is open downward and upward and is configured such that the inner diameter dimension gradually becomes shorter upward.

[0052] Note that a cylindrical reinforcing metal member 42 is embedded in the first outer fitting portion P of the seat receiver 4.

[0053] For the seat receiver 4 to perform the telescopic operation of the leg support 2, an operation lever D that can press a lock release button g1 provided at the tip of the gas spring G is rotatably supported. A bearing portion 41 for rotatably supporting the operation lever D is provided in the vicinity of the first outer fitting portion P on the upper surface side of the seat receiver 4.

[0054] Waist rest attachment portions 43 to which waist rests F are attached are provided on both left and right side portions of the seat receiver 4. A pair of nut portions n3 to which screws v3 for attaching the waist rests F are screwed are provided on the left and right waist rest attachment portions 43, respectively.

[0055] <Connecting reinforcement screw E> In this embodiment, a connecting reinforcement screw E, which is a male screw, is interposed between the leg A and the seat C.

[0056] The connection strengthening screw E is screwed between the upper inner fitting M provided at the upper end of the piston rod g2 in the gas spring G and the seat receiver 4, more specifically, between the upper inner fitting M and the first outer fitting P formed at the central portion of the seat receiver 4. The connection strengthening screw E is configured to be engageable with both the upper inner fitting M of the gas spring G and the first outer fitting P of the seat receiver 4.

[0057] The connection strengthening screw E is screwed into the notched nut portion Q provided on the first outer fitting P. The notched nut portion Q has a shape in which a part of the thread portion e1 of the screwed connection strengthening screw E is cut out so as to be able to contact the piston rod g2.

[0058] In other words, the notched nut portion Q includes a nut portion main body q1 that engages with the thread portion e1 of the connection strengthening screw E, and a notch q2 that communicates between a space formed in a part of the nut portion main body q1 and surrounded by the nut portion main body q1 and the space of the first outer fitting P.

[0059] When the connection strengthening screw E is screwed into the notched nut portion Q, the connection strengthening screw E is guided by the notched nut portion Q and is screwed and enters downward. Then, the thread portion e1 of the connection strengthening screw E protruding to the space side of the first outer fitting P through the notch q2 firmly engages with the outer surface of the upper inner fitting M of the metal piston rod g2 while shaving the outer surface of the upper inner fitting M in the process of screwing and entering the nut portion main body q1 downward.

[0060] That is, in this embodiment, by using the connection strengthening screw E, the degree of connection between the upper inner fitting M and the first outer fitting P is strengthened as compared with the case where the upper inner fitting M and the first outer fitting P are simply fitted together.

[0061] Note that the connection strengthening screw E has the same configuration as a known screw. That is, the connection strengthening screw E is made of metal and has a substantially triangular thread portion e1 provided on the outer peripheral surface.

[0062] <<Footrest Cover B>> The footrest cover B is cylindrical with the footrest 2 disposed inside, and its upper end is supported by the seat receiver 4. The footrest cover B can cover at least the upper part of the footrest 2 that can expand and contract in the vertical direction so that the upper end of the cylinder cover I is not exposed to the outside.

[0063] On the upper part of the footrest cover B, a nut portion n2 exposed upward is provided. The footrest cover B is attached to the lower surface side of the seat receiver 4 by screwing a screw v2 inserted through a screw insertion hole h2 provided in the seat receiver 4 to the nut portion n2.

[0064] <<Backrest F>> The backrest F can support the waist of the seated person. The backrest F of this embodiment is attached to the seat C. The backrest F also serves as a part that can be gripped so that the user can lift the entire chair away from the floor surface R when moving the entire chair.

[0065] The backrest F has a belt-like shape and is curved so as to be convex rearward in plan view, with an abutting surface 5s on the inner surface that can abut against the waist of the seated person, and seat attachment portions 6 provided at the left and right front end portions 5L, 5R of the backrest body 5 and attached to the seat C. The backrest F is made of synthetic resin in which the backrest body 5 and the seat attachment portions 6 are integrally formed.

[0066] In plan view, the backrest F is set such that there is a gap between the rear end portion ct at the center in the left-right direction of the seat C and the front end portion ft at the center in the left-right direction of the backrest body 5.

[0067] In other words, a separation space U into which a hand can be inserted is formed between the seat C and the backrest F.

[0068] In addition, as shown in FIGS. 2 and 3, a horizontally communicating space is formed between the lower end edge 5b of the lumbar support body 5 and the upper surface of the seat C in the front view and the rear view.

[0069] As shown in FIG. 12, the separation space U is provided not only at a position visible in the plan view but also at a position visible in the front view. Therefore, when trying to carry the chair, in order to use the lumbar support F as a handle part of the user, the hand of the user can be easily inserted into the lower end edge side of the lumbar support body 5.

[0070] <lumbar support body 5> The lumbar support body 5 is set to have substantially the same vertical width dimension between the left front end 5L which is one end and the right front end 5R which is the other end. In other words, except for the left front end 5L and the right front end 5R having a partial arc-shaped outer edge, the vertical separation distance w3 between the upper end edge 5a and the lower end edge 5b of the lumbar support body 5 is set to be substantially constant.

[0071] As shown in FIGS. 4 and 5, both left and right side portions of the lumbar support body 5 form a belt shape extending in the front-rear direction in the side view, and are inclined so as to be gradually positioned upward toward the rear. In addition, the left and right front edges 5t of the lumbar support body 5 form a semi-circular arc shape in the side view.

[0072] As shown in FIGS. 2 and 3, the central portion of the lumbar support body 5 in the left-right direction forms a belt shape extending in the left-right direction in the front view or the rear view. The lumbar support body 5 is gently curved so as to be gradually positioned upward from both left and right side portions toward the central portion in the left-right direction in the front view or the rear view.

[0073] As shown in FIGS. 11 and 12, the contact surface 5s of the central portion of the lumbar support body 5 in the left-right direction is inclined so as to be gradually positioned forward downward. In addition, the central portion of the lumbar support body 5 in the left-right direction is formed so that the front-rear thickness dimension gradually becomes longer downward.

[0074] As shown in FIG. 6, the lumbar support main body 5 has a substantially U-shaped configuration in plan view.

[0075] <Seat attachment portion 6> As shown in FIGS. 8 and 9, the seat attachment portion 6 includes an inward protruding portion 61 integrally protruding inward from the inner surface side of the left and right front end portions of the lumbar support main body 5, and screw insertion holes h3 penetrating in the vertical direction provided at two locations, front and rear, of the inward protruding portion 61.

[0076] Nut portions n3 opened upward are provided at both left and right ends of the seat receiver 4. The lumbar support F is attached to the lumbar support attachment portion 43 of the seat receiver 4 by screwing a screw v3 inserted through the screw insertion hole h3 provided in the inward protruding portion 61 to the nut portion n3.

[0077] The chair of the above-described embodiment is configured with a lumbar support F, which contributes to comfortable use by the seated person. Moreover, in this chair, as shown in FIG. 6, in plan view, there is a gap between the rear end portion ct at the center in the left-right direction of the seat C and the front end portion ft at the center in the left-right direction of the lumbar support main body 5, so that a suitable configuration is adopted in which the user can grip the lumbar support main body 5 for moving the chair or the like.

[0078] Also, in the chair of the above-described embodiment, as shown in FIGS. 14 and 15, a connecting reinforcement screw E, which is a connecting reinforcement means interposed between the upper inner fitting portion M and the seat receiver 4, that is, a connecting reinforcement screw E screwed between the upper inner fitting portion M and the seat receiver 4 and engageable with both the upper inner fitting portion M and the seat receiver 4 is provided, so that the seat receiver 4 fitted to the gas spring G has a suitable configuration in which it is difficult to come off from the gas spring G.

[0079] As described above, the chair according to the present embodiment includes a seat C and legs A that can support the seat C so as to be vertically movable.

[0080] The leg A includes a leg base 1 and a leg support 2 provided upright with respect to the leg base 1 and having a gas spring G that can expand and contract in the vertical direction. The seat C includes a seat receiver 4 having a first outer fitting portion P that can be fitted into an upper inner fitting portion M provided at the upper portion of the gas spring G. A connecting and strengthening means is provided between the upper inner fitting portion M and the seat receiver 4 and can engage with both the upper inner fitting portion M and the seat receiver 4.

[0081] The connecting and strengthening means is a connecting and strengthening screw E screwed between the upper inner fitting portion M and the seat receiver 4.

[0082] Therefore, in this embodiment, at least a chair having a suitable configuration can be provided in which the seat receiver 4 fitted to the gas spring G is difficult to come off with respect to the gas spring G.

[0083] The gas spring G includes a cylinder g1 extending in the vertical direction and a piston rod g2 having an upper inner fitting portion M and supported so as to be vertically movable with respect to the cylinder g1.

[0084] The leg base 1 includes a leg base body 11 having a second outer fitting portion J into which a lower inner fitting portion K provided at the lower end of the cylinder g1 can be fitted, and a leg base cover 12 attached to the upper surface side of the leg base body 11. The leg support 2 includes a cylinder cover I that covers the cylinder g1 of the gas spring G.

[0085] The leg base cover 12 and the cylinder cover I are integrally formed. The cylinder cover I is provided with an inwardly extending flange i2 that is disposed on the cylinder g1 and can regulate the detachment of the gas spring G from the cylinder cover I.

[0086] Therefore, due to the configuration in which the upper inner fitting portion M of the piston rod g2 and the first outer fitting portion P of the seat receiver 4 are fitted, the seat C is suitably attached to the leg A.

[0087] In addition, even if the lower fitting portion K of the gas spring G comes off from the second outer fitting portion J in the leg base body 11, the gas spring G is configured not to separate from the cylinder cover I for the leg A.

[0088] The cylinder cover I includes a cylinder cover body i1 having a substantially cylindrical shape and integrally connected to the leg base cover 12 at the lower end, and an inward extending flange i2 that forms a detachment restricting portion and extends integrally inward from the upper portion of the cylinder cover body i1.

[0089] Therefore, the cylinder cover I is provided with the inward extending flange i2, which is a detachment restricting portion, in a manner that is excellent in appearance and suppresses the number of parts.

[0090] The leg base 1 is integrally connected to the leg support 2 and has a substantially curved surface shape that can contact the floor surface R with the lower surface.

[0091] Therefore, in the case of the chair of this embodiment, the entire chair can tilt with respect to the floor surface R, and even in a state where the entire chair is tilted with respect to the floor surface R, a configuration is adopted in which the seated person can sit on the seat C.

[0092] The seat C is provided with a lumbar support F that can be attached to the lumbar region of the seated person, and the lumbar support F has a portion that the user can grip when moving the entire chair.

[0093] Therefore, in the chair of this embodiment, since the lumbar support F is used as a gripping portion, the chair has a configuration in which the entire chair can be easily moved by the user.

[0094] It includes a leg support cover B having a cylindrical shape with the leg support 2 disposed inside and the upper end supported by the seat receiver 4.

[0095] Therefore, it can suitably cover the upper portion of the leg support 2 including the piston rod g2 of the gas spring G.

[0096] Note that the present invention is not limited to the embodiments described in detail above.

[0097] The connection strengthening means is not limited to the connection strengthening screw. The connection strengthening means may be any means as long as it is interposed between the upper fitting portion of the leg and the seat receiver and can engage with both the upper fitting portion and the seat receiver.

[0098] Examples of other connection strengthening means include a spring pin or a push nut inserted between the upper fitting portion and the seat receiver.

[0099] Also, as other connection strengthening means, for example, an elastic member (such as a thin film-shaped or O-ring-shaped rubber member) that can be interposed between the upper fitting portion and the seat receiver to impart frictional resistance may be used.

[0100] The seat may not be provided with a lumbar support.

[0101] The seat may not be provided with a dedicated hole into which the connection strengthening screw is inserted.

[0102] The leg base and the gas spring do not necessarily have to be connected by fitting.

[0103] The cylinder cover may not be provided with a detachment restricting portion.

[0104] The detachment restricting portion is not limited to being extended in a flange shape from the upper end portion of the cylinder cover body. For example, it may be intermittently projected so as to be located above the cylinder.

[0105] In addition, the specific configuration of each part is not limited to the above embodiments, and various modifications are possible without departing from the gist of the present invention.

Explanation of Reference Numerals

[0106] C... Seat A… leg 1… leg base 2… leg support G… gas spring P… first outer fitting part 4… seat bearing M… upper inner fitting part E… connecting reinforcement screw

Claims

1. A chair comprising a seat and legs capable of supporting the seat in a vertically movable manner, wherein the legs include a leg base and a leg column provided upright on the leg base and having a gas spring that can expand and contract in the vertical direction, the seat includes a seat receiver having a first outer fitting portion that can be fitted into an upper inner fitting portion provided at the upper part of the gas spring, a connection strengthening means is provided between the upper inner fitting portion and the seat receiver and can engage with both the upper inner fitting portion and the seat receiver, the gas spring includes a cylinder extending in the vertical direction and a piston rod having the upper inner fitting portion and supported so as to be vertically movable with respect to the cylinder, the leg base includes a leg base body having a second outer fitting portion into which a lower inner fitting portion provided at the lower end of the cylinder can be fitted, and a leg base cover attached to the upper surface side of the leg base body, the leg column includes a cylinder cover covering the cylinder, the leg base cover and the cylinder cover are integrally formed, and a separation restricting portion is provided on the cylinder cover above the cylinder to restrict the gas spring from separating from the cylinder cover.

2. A chair comprising a seat and legs capable of supporting the seat in a vertically movable manner, wherein the legs include a leg base and a leg column provided upright on the leg base and having a gas spring that can expand and contract in the vertical direction, the seat includes a seat receiver having a first outer fitting portion that can be fitted into an upper inner fitting portion provided at the upper part of the gas spring, a connection strengthening means is provided between the upper inner fitting portion and the first outer fitting portion and can engage with both the upper inner fitting portion and the first outer fitting portion, the connection strengthening means is a connection strengthening screw screwed between the upper inner fitting portion and the first outer fitting portion, and the connection strengthening screw is screwed into a notched nut portion provided on the first outer fitting portion, and the notched nut portion has a shape notched so that a part of the thread side surface of the screwed connection strengthening screw can contact the upper inner fitting portion.

3. The chair according to claim 1, wherein the connection strengthening means is a connection strengthening screw screwed between the upper inner fitting portion and the first outer fitting portion.

4. The chair according to claim 1, wherein the cylinder cover has a substantially cylindrical shape, and a cylinder cover body integrally connected to the leg base cover at its lower end, and has an inwardly extending flange integrally extending inward from the upper part of the cylinder cover body and constituting the detachment restricting portion.

5. The chair according to claim 1, 2, 3 or 4, wherein the leg base is integrally connected to the leg support and has a substantially curved surface shape such that its lower surface can contact the floor surface.

6. The chair according to claim 1, 2, 3, 4 or 5, further comprising a lumbar support attached to the seat and adapted to abut against the lumbar region of the seated person, and the lumbar support having a portion that can be grasped by the user when moving the entire chair.

7. The chair according to claim 1, 2, 3, 4, 5 or 6, further comprising a leg support cover having a cylindrical shape with the leg support disposed therein and having an upper end supported by the seat receiver.

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