WO2023171794A1

WO2023171794A1 - Chair

Info

Publication number: WO2023171794A1
Application number: PCT/JP2023/009292
Authority: WO
Inventors: 浩益永
Original assignee: 株式会社オカムラ
Priority date: 2022-03-11
Filing date: 2023-03-10
Publication date: 2023-09-14
Also published as: JP2023132854A

Abstract

This chair (1) has: a support structure (40); a backrest (20) supported by the support structure so as to be capable of rotating about a first axis (42a) extending in the width direction of the support structure, it being possible to displace the backrest to an inclined state of being inclined rearward from an initial state; a regulating part (93) that regulates rotation of the backrest about the first axis; a return part (92) causing the backrest in the inclined state to return to the initial state; a first operation member (95) for allowing a seated person to operate the regulating part (93); a second operation member (80) for allowing the seated person to operate the return part (92); and a base member (91) that supports the first operation member (95) and the second operation member (80), the base member (91) extending in the width direction, the first operation member (95) being supported by a first support part (912) provided to one width-direction end of the base member (91), and the second operation member (80) being supported by a second support part (913) provided to the other width-direction end of the base member (91).

Description

Chair

The present invention relates to a chair.
This application claims priority based on Japanese Patent Application No. 2022-038415 filed in Japan on March 11, 2022, the contents of which are incorporated herein.

BACKGROUND ART Conventionally, chairs used for office work, etc., have been known to have a backrest that is rotatably supported around an axis along the width direction of the chair with respect to a support structure that supports the backrest and the seat. . Such a chair includes a regulating part that regulates the above-mentioned rotation of the backrest, a biasing part that stores a force to return the backrest rotated around the axis to its initial state, and an adjustment part that adjusts the biasing part. (For example, see Patent Document 1).

Japanese Patent No. 4848099

In the chair disclosed in Patent Document 1, the operating lever for operating the regulating section and the knob of the adjusting section are arranged at positions separated from each other in the front-rear direction. For this reason, when operating the regulating section and operating the adjusting section in succession, the seated person needs to change his or her posture, resulting in poor operability. Furthermore, during assembly, the operating lever for operating the regulating section and the knob of the adjusting section cannot be assembled together, making it difficult to form a unit and resulting in poor workability during assembly.

Therefore, an object of the present invention is to provide a chair with good operability and workability during assembly.

In order to achieve the above object, a chair according to one aspect of the present invention includes a support structure, the chair is rotatably supported with respect to the support structure about a first axis extending in the width direction of the support structure, and a backrest that is displaceable from a tilted state to a tilted state; a regulating portion that restricts rotation of the backrest about the first axis; and a return of the backrest in the tilted state to the initial state. a first operation member for the seated person to operate the regulating section; a second operation member for the seated person to operate the return section; the first operation member and the second operation member; a base member that supports the base member, the base member extending in the width direction, and the first operation member being supported by a first support part provided at one end side of the base member in the width direction. The second operating member is supported by a second support portion provided at the other end of the base member in the width direction.

In the aspect of the present invention, the first operating member is supported on one side of the base member in the width direction, and the second operating member is supported on the other side of the base member in the width direction. This allows the seated person to operate the restriction part with one hand in the width direction while seated, and operate the return part with the other hand in the width direction without changing their posture, improving operability. good. Furthermore, interference between the first operating member and the second operating member can be prevented. Furthermore, since the first operating member and the second operating member can be provided together via the base member, unitization is easy and workability during assembly is good.

Furthermore, in the chair according to the aspect of the present invention, the base member may have a rod shape extending in the width direction.

With such a configuration, the space occupied by the base member can be reduced, and a large space can be secured for arranging other members such as the regulating part and the return part.

Further, in the chair according to the aspect of the present invention, the base member is a shaft portion having a second axis extending in the width direction, and the first operating member and the second operating member are arranged on the second axis. may be coaxially arranged.

With such a configuration, the base member, the first operating member, and the second operating member are arranged side by side in the width direction, so the space occupied by these members can be reduced.

Further, in the chair according to the aspect of the present invention, the return portion is linked to a spring that urges the backrest in the tilted state in a direction to return to the initial state, and the second operating member, an adjustment unit that adjusts the biasing force of the spring, the base member is rotatable about the second axis, and the first operating member is rotatable relative to the base member about the second axis. The second operating member may be rotatable, and the second operating member may be fixed to the base member so as not to rotate relative to the second axis.

With such a configuration, the operating force of the second operating member can be directly transmitted to the spring.

Furthermore, in the chair according to the aspect of the present invention, the regulating portion and the returning portion may be arranged at positions with the base member sandwiched therebetween when viewed from the width direction.

With such a configuration, the restriction part and the return part can be arranged at positions where they do not interfere with each other.

Further, in the chair according to the aspect of the present invention, the backrest has two side walls arranged at intervals in the width direction, and the first operating member is arranged on one side in the width direction. The second operating member may be supported by a side wall disposed on the other side in the width direction.

With such a configuration, the first operating member and the second operating member are arranged in a dispersed manner in the width direction, so that both the first operating member and the second operating member are placed on either side in the width direction. Compared to the case where the seated person is arranged, it is possible to prevent the seated person from erroneously operating the first operating member and the second operating member.

Further, in the chair according to the aspect of the present invention, the base member has an intermediate part between the first support part and the second support part, and both ends of the intermediate part in the width direction are connected to the base member. It may be supported by two collars provided on the chair.

With such a configuration, the base member is reliably supported by the chair, and the first operating member and the second operating member can be operated in a stable state.

According to the present invention, a chair with good operability and workability during assembly can be provided.

FIG. 1 is a perspective view of a chair according to an embodiment of the invention. FIG. 2 is a perspective view of the chair with the upholstery removed from the rear. FIG. 1 is an exploded perspective view of a chair according to an embodiment of the present invention. FIG. 3 is a side view of a portion of the chair with the rear cover removed. FIG. 5 is a perspective view of FIG. 4 viewed from above. FIG. 5 is a view of FIG. 4 viewed from above. It is a perspective view showing a return part and a regulation part. FIG. 8 is a plan view of FIG. 7; It is a perspective view showing a foundation member and a support member. It is a perspective view showing a foundation member. It is an exploded perspective view explaining a base member and an operation member. 9 is a cross-sectional perspective view taken along the line XII-XII in FIG. 8. FIG. It is an exploded perspective view explaining a base member and an operation member. 9 is a sectional view taken along the line XIV-XIV in FIG. 8. FIG. It is a perspective view explaining a foundation member, a connection member, and an operation member. It is a perspective view of a connection member. It is a figure explaining operation of a connection member and an engagement member. It is a figure explaining operation of an engagement member.

Hereinafter, a chair according to an embodiment of the present invention will be described based on FIGS. 1 to 18.
In the following description, for convenience of explanation, the direction in which a seated person sitting in a normal posture on the seat 17 (described later) faces forward will be referred to as the "front", and the opposite direction will be referred to as the "rear". Further, in the following explanation, the directions of up and down and left and right mean directions that match the directions centered on the seated person when the seated person is seated in the seat 17 in a normal posture. The side where the legs 10 (described later) are located is referred to as the lower side of the chair, the side where the backrest 20 (described later) is located is referred to as the upper side of the chair, and the right side of the seated person who is seated in a normal posture on the seat 17 is referred to as the right side of the chair. The left side of the person is called the left side of the chair. In the following description, the left-right direction at this time is also referred to as the width direction. Note that an arrow FR pointing forward, an arrow UP pointing upward, and an arrow LH pointing leftward are written at appropriate locations in the figure.

As shown in FIG. 1, the chair 1 according to the present embodiment includes a leg section 10 installed on a floor surface F, a box-shaped support base 40 installed on the upper part of the leg section 10, and an upper part of the support base 40. a backrest 20 that is attached to the rear of the support base 40 and supports the back of the seated person; It includes an armrest 19 on which the elbow and arm rest. The support base 40 corresponds to the support structure of the present invention.

The leg portion 10 has a multi-legged leg 11 with casters 11a, and a pedestal 12 that stands up from the center of the multi-legged leg 11 and has a built-in gas spring (not shown) serving as an elevating mechanism. The pedestal 12 has an outer cylinder 13 and an inner cylinder 14. The outer cylinder 13 is non-rotatably fitted and supported by the manifold leg 11. The lower part of the inner cylinder 14 is supported by the outer cylinder 13 so as to be horizontally rotatable (rotatably around an axis extending vertically). The upper part of the inner cylinder 14 is fixed to a support base 40. The support base 40 has a built-in mechanism for adjusting the elevation of the pedestal 12 and a tilting mechanism for the backrest 20.

The backrest 20 includes a backrest structure 20A (see FIG. 2) and an upholstery 26 that covers the backrest structure 20A. The backrest structure 20A receives the back of the seated person. As shown in FIG. 2, the backrest structure 20A includes a backrest support 21 and a backrest main body 23 supported by the backrest support 21.

The backrest support 21 supports the back of the seated person. The backrest support 21 includes a backrest support member 30 and a rear extension member 22.

As shown in FIG. 3, the backrest support member 30 includes an inner member 31 and an outer member 32. The inner member 31 has an elongated shape in the vertical direction. The inner member 31 is formed into a flat plate shape.

The outer member 32 has an outer upper and lower extending portion 35 and an outer upper extending portion 36. The outer vertically extending portion 35 has an outer curved upper part 351, an outer curved lower part 352, and an outer lower part 353. Inner member 31 and outer member 32 are connected by screws.

The backrest support member 30 is rotatable via a rotation main shaft 42 that is fixed to the inner member 31 and the outer member 32 and extends in the axial direction along the width direction (horizontal direction) at the rear of the support base 40. A rotating member 38 is provided. The axis 42a of the rotation main shaft 42 corresponds to the first axis of the present invention. As shown in FIG. 4, the rotating member 38 is rotatable about an axis extending in the left-right direction with respect to the support base 40. As shown in FIG. As shown in FIG. 3, bolts 38a are formed in the mounting hole 353b provided in the mounting recess 353a of the outer lower part 353 of the outer member 32, the mounting hole 334a of the inner lower fixing part 334 of the inner member 31, and the rotating member 38. A nut is fastened to the bolt 38a. Thereby, the inner member 31 and the outer member 32 are fixed to the rotating member 38 as one body.

As shown in FIG. 3, the rotating member 38 and the outer lower part 353 of the outer member 32 are covered from behind by a rear cover 37.

As shown in FIGS. 1 and 2, the backrest 20 configured in this manner is rotatably supported by the backrest support member 30 around an axis along the width direction of the backrest support member 30, and has an upper end portion 20a. The upper end portion 20a is movable from an initial state where the upper end portion 20a is located relatively forward to a tilted state (see FIG. 11) where the upper end portion 20a is located relatively rearward.

As shown in FIG. 4, a seat shell 51 that holds the seat 17 from below is provided below the seat 17. The seat shell 51 is provided on a seat support member 50 that is supported from below by the support base 40. The seat shell 51 is secured by a locking portion (not shown) provided on the lower surface of the rear end of the seat shell 51 from the rear of the seat support member 50, and screwed onto the front edge 50a of the seat support member 50. It is fixed with a fixing member such as.

The seat support member 50 includes the above-mentioned seat shell 51, a main body part 52 having a rectangular shape in plan view to which the seat shell 51 can be attached to the upper edge, and a main body part 52 extending downward and rearward from the rear end part 52a of the main body part 52. An extended rear mounting portion 53, two elongated holes 54 extending in the front-rear direction on both left and right sides of the front lower surface 52b of the main body portion 52, and a spring front end receiving portion 55 fixed to the front portion of the main body portion 52. We are prepared. The seat support member 50 is a strength member made of a metal material such as a drawn sheet metal or die-cast aluminum, and has a saucer shape with an open upper side in the vertical direction.

The seat support member 50 has a bottom wall portion 501 and a side wall portion 502 that stands up from the peripheral edge of the bottom wall portion 501. The above-described seat shell 51 is attached to the upper end of the side wall portion 502. A recess 503 is formed in the bottom wall portion 501 and is recessed upward in a shape that follows the outer shape of the compression coil spring 61 so as not to interfere with the compression coil spring 61, which will be described later.

The rear mounting portion 53 is provided on the rotating member 38 of the backrest support member 30, and is rotatably connected to a sub-shaft 39 of an operating portion 80 (second operating member) that extends along the left-right direction, which will be described later. The rear mounting portion 53 (that is, the seat support member 50) is rotatable about the secondary shaft 39 with respect to the rotation member 38. That is, the seat support member 50 moves rearward with respect to the support base 40 when the backrest 20 changes from the initial state to the tilted state.

As shown in FIGS. 5 and 6, each of the two elongated holes 54 provided on both sides of the front portion of the bottom wall portion 501 in the left and right direction has a hole that protrudes upward from the front portion of the support base 40 (see FIG. 4). The sliding engagement portion 43 is slidably engaged along the longitudinal direction (front-back direction) of the elongated hole 54 while being prevented from moving downwardly from the elongated hole 54 . When the backrest 20 tilts, the elongated hole 54 slides rearward relative to the slide engagement portion 43 provided on the support base 40, and the seat support member 50 moves rearward. That is, when the seat support member 50 moves rearward, the position of the slide engagement portion 43 in the front-rear direction with respect to the elongated hole 54 becomes the position moved from the rear side to the front side.

As shown in FIGS. 7 and 8, the spring front end receiving portion 55 has two fixing portions 551 provided on both sides in the left-right direction and fixed to the lower surface of the bottom wall portion 501; It has a front spring reaction force receiving shaft 553 that is supported in this state and extends with its axial direction directed in the left-right direction. The fixing portion 551 is formed with an insertion hole 551a through which the front spring reaction force receiving shaft 553 is inserted.
The fixing portion 551 is provided at a position where it does not interfere with a compression coil spring 61, which will be described later, and which is supported by the front spring reaction force receiving shaft 553.

The front spring reaction force receiving shaft 553 is a bar with a circular cross section. Both ends of the front spring reaction force receiving shaft 553 in the axial direction are inserted into the insertion holes 551a of the fixing parts 551 and fixed, and are provided so as not to move in the left-right direction with respect to the two fixing parts 551. The front end portions of two compression coil springs 61 that are biased in the compression direction from the rear are supported by the front spring reaction force receiving shaft 553 .

The support base 40 includes a support base body portion 41 fixed to the upper portion of the pillar 12 (see FIG. 1), and a rotation member 38 of the backrest support member 30 that rotates in a direction to tilt relative to the support base body portion 41. It includes a rotation main shaft 42 that supports the seat support member 50 so as to be movable, and a slide engagement portion 43 that supports the seat support member 50 so as to be slidable in the front-rear direction.

The supporting body portion 41 has a bottom plate 411 and side plates 412 extending upward from both left and right sides of the bottom plate 411, and is generally formed into a bowl shape that opens upward. Two compression coil springs 61 are accommodated in the first internal space S1 above the support body portion 41. As shown in FIG. 4, the rear end portion 41a of the support body portion 41 projects further rearward than the rear upper portion 412a of the side plate 412. As shown in FIG. In the support base body portion 41, a rotation main shaft 42 is provided at the rear upper portion 412a of the side plate 412 located on both left and right sides.

As shown in FIGS. 4, 7, and 8, the front part of the rotation member 38 of the backrest support member 30 is rotatably supported on the rotation main shaft 42 inside the rear part of the support base body part 41. There is. The rotation main shaft 42 is provided on each of the left and right side plates 412. The rotation centers of the left and right rotation main shafts 42 are coaxial.

The slide engagement portions 43 are provided at the front upper ends 412b of the left and right side plates 412 of the support base body portion 41 in a state of protruding upward. The slide engagement portion 43 includes a protrusion 431 and a sliding portion 432 that is provided at the upper end of the protrusion 431 and has a larger diameter than the protrusion 431 . The protrusion 431 is formed to have a circular cross section with a diameter that is approximately the same as the width of the elongated hole 54 (see FIGS. 5 and 6) of the seat support member 50. In the slide engagement portion 43, the protrusion portion 431 is inserted into the elongated hole 54, and the sliding portion 432 is disposed inside the seat support member 50. Note that the inner portion of the seat support member 50 where the sliding portion 432 is arranged is above the upper surface of the bottom wall portion 501 and is a portion between the opposing surfaces of the side wall portions 502. The sliding area of the sliding part 432 in the inner part of the seat support member 50 is located at a position that avoids the recessed part 503 (see FIGS. 5 and 6) that is recessed upward in a shape that follows the outer shape of the compression coil spring 61. Therefore, there is a space in which the sliding portion 432 that slides does not interfere with other parts. That is, the sliding areas of the elongated hole 54 and the sliding portion 432 are set at positions on both the left and right side, avoiding the two compression coil springs 61 when viewed from above.

As shown in FIGS. 7 and 8, the support body portion 41 of the support base 40 and the rotating member 38 include a return portion 92 that returns the backrest 20 in the tilted state to the initial state, and a return portion 92 that returns the backrest 20 in the tilted state to the initial state. A regulating portion 93 that regulates rotation around the rotation main shaft 42 is provided.

The return unit 92 includes a biasing unit 60 that includes a compression coil spring 61 (spring) that biases the backrest 20 in a tilted state in a direction to return to the initial state, and an adjustment unit that adjusts the biasing force of the compression coil spring 61. 70 , and an operating section 80 that is connected to the adjustment section 70 and operates the adjustment section 70 .

The rotating member 38 has a rear wall 381 and two

side walls

382a and 382b that extend from both left and right ends of the rear wall 381 in a direction orthogonal to each other and are spaced apart in the width direction. The adjustment section 70 and the operation section 80 are accommodated in the second internal space S2 on the front side of the rotation member 38. Further, a rear end portion of the compression coil spring 61 is supported at the front portion of the second internal space S2.

The two

side walls

382a and 382b of the rotation member 38 are rotatably supported by the rotation main shaft 42 with respect to the rear upper part 412a of the side plate 412 of the support base body portion 41. The adjustment section 70 and the operating section 80 are arranged in the second internal space S2 located behind the rotation main shaft 42 of the rotation member 38. The rotating member 38 supports a rotating main shaft 42 at the front portion. Further, the rotating member 38 includes a subshaft 39 at the rear portion to which a rear mounting portion 53 (see FIG. 4) of the seat support member 50 is attached. The rotating member 38 supports an operating shaft 81 of the operating section 80 at an intermediate portion between the front and rear portions.

The sub-shaft 39 extends in the left-right direction and is supported by the left and

right side walls

382a and 382b. A connecting piece 532 (see FIG. 4) of the rear mounting portion 53 of the seat support member 50 is rotatably supported on the subshaft 39. That is, the rear portion of the seat support member 50 is rotatably supported by the rotation member 38.

The biasing unit 60 is configured to have a returning force for returning the backrest 20 tilted by the biasing force to its original position (initial state). The biasing section 60 includes a compression coil spring 61, a spring front end support section 62 provided at one end (front end) of the compression coil spring 61, and a spring rear end provided at the other end (rear end). It has a support part 63.

The compression coil spring 61 has a front end compressed backward and a rear end compressed forward. The first internal space S1 of the support base body portion 41 accommodates two compression coil springs 61 arranged in the left-right direction, with the biasing direction of the springs directed in the front-rear direction. The two compression coil springs 61 are attached in such a state that they are always compressed and generate a biasing force, regardless of whether the backrest 20 is in the initial state or in the tilted state.

The spring front end support part 62 and the spring rear end support part 63 are connected by a telescopic connecting shaft 64 inserted inside the compression coil spring 61. In the biasing section 60, the telescopic connecting shaft 64 expands and contracts as the distance between the spring front end support section 62 and the spring rear end support section 63 changes due to the compression and expansion of the compression coil spring 61.

The spring front end support portion 62 is in contact with the front end of the compression coil spring 61 from the front. The spring front end support portion 62 is formed in a U-shape that opens forward when viewed from the left and right directions. The U-shaped concave portion 62a (see FIG. 7) engages with the front spring reaction force receiving shaft 553 of the spring front end receiving portion 55 provided in the seat receiving member 50 while being pressed from behind. That is, the front spring reaction force receiving shaft 553 takes charge of the reaction force caused by the compression coil spring 61 whether the backrest 20 is in the initial state or the tilted state.

The spring rear end support portion 63 is in contact with the rear end of the compression coil spring 61 from the rear. The spring rear end support portion 63 has a through hole 631 (see FIG. 7) that penetrates in the left-right direction. The through hole 631 supports an operating shaft 71 (shaft portion 712, see FIG. 8) extending in the left-right direction of the adjustment portion 70, which will be described later, in a state where it is inserted therein.
The spring rear end support portion 63 is in a state where a spring force is applied to the operating shaft 71 from the front. That is, the operating shaft 71 is in charge of the reaction force exerted by the compression coil spring 61 whether the backrest 20 is in the initial state or in the tilted state.

The adjustment unit 70 has a function of adjusting the biasing force of the compression coil spring 61 of the biasing unit 60 and adjusting the return force of the backrest 20 in a tilted state. The adjustment part 70 is accommodated in the second internal space S2 between the

side walls

382a and 382b of the rotating member 38 of the backrest 20.
The adjustment section 70 includes an action shaft 71 that acts on the urging force of the urging section 60 (compression coil spring 61), an adjustment shaft 72 that movably supports the action shaft 71, and an adjustment shaft 72 that rotates with respect to the operation section 80. A support member 73 that can support the device.

The adjustment shaft 72 is integrally provided with a second transmission gear 721 made of a bevel gear at its upper end. The second transmission gear 721 meshes with a first transmission gear 83 of the operating section 80, which will be described later, and when the operating shaft 81 of the operating section 80 is operated, a rotational force is transferred from the first transmission gear 83 to the second transmission gear 721. is transmitted, and the adjustment shaft 72 rotates in both forward and reverse directions. The adjustment shaft 72 is formed with a male screw threadedly engaged with the operating shaft 71 over the entire axial direction. The adjustment section 70 is linked to the operation of the operation section 80.

In the initial state, the adjustment shaft 72 is arranged with its axial direction oriented obliquely from the front to the rear as it goes from the shaft lower end 72b to the shaft upper end 72a in side view. The shaft lower end portion 72b is located below the rotation main shaft 42. The shaft upper end portion 72a is located above and behind the rotation main shaft 42. In other words, the action shaft 71 that moves along the adjustment shaft 72, that is, the spring rear end support portion 63 provided at the rear end of the compression coil spring 61 connected to the action shaft 71, is located at a position lower than the rotation main shaft 42. , and a position above and behind the rotation main shaft 42.

In the adjustment section 70, as the adjustment shaft 72 rotates, the working shaft 71, which is screwed into the male screw, moves in the axial direction of the adjustment shaft 72 according to the rotational position of the adjustment shaft 72. That is, in the adjustment section 70, the position of the working shaft 71 can be adjusted by moving the working shaft 71 along the adjusting shaft 72. When the operating shaft 71 moves on the adjustment shaft 72, the compression coil spring 61 rotates around the spring front end support portion 62, so that only the angle seen from the left and right changes.

The support member 73 includes a fixed plate 731 that extends in the vertical direction and is fixed to the rear wall 381 of the rotating member 38 with screws (not shown), and an upper plate that extends forward from the upper and lower ends of the fixed plate 731. It has a support plate 732, a lower support plate 733, and two side support plates 734 and 735 (two flanges) extending upward from both sides of the upper support plate 732 in the left and right direction. Of the two

side support plates

734 and 735, the left side support plate 734 is referred to as a first side support plate 34, and the right side support plate 735 is referred to as a second side support plate 735. The adjustment shaft 72 is arranged between an upper support plate 732 and a lower support plate 733. The adjustment shaft 72 has an upper shaft end 72a rotatably supported by an upper support plate 732, and a lower shaft end 72b rotatably supported by a lower support plate 733.

As shown in FIGS. 6 and 7, the operating shaft 71 includes a nut portion 711 having a female thread that is screwed into the adjustment shaft 72, and a shaft portion 712 extending to both left and right sides of the nut portion 711. The nut portion 711 moves along the adjustment shaft 72 by rotation of the nut 72 on the adjustment shaft. A spring rear end support portion 63 of the biasing portion 60 is connected to the shaft portion 712 .

As shown in FIG. 7, the operating section 80 is provided on the rotating member 38. The operating portion 80 includes an operating shaft 81 extending along the left-right direction and inserted into a hole 382c formed in the right side wall 382a, and protruding outward (to the right) from the right side wall 382a of the operating shaft 81. It has an operating lever 82 provided at a protruding tip (one end), and a first transmission gear 83 formed of a bevel gear provided at an intermediate portion of the operating shaft 81 and located in the second internal space S2. That is, in the operating part 80, the outer end in the width direction of the operating shaft 81 protrudes in the width direction from the right side wall 382a, while the inner part in the width direction is arranged in the second internal space S2, and the adjusting part 70.

The operating shaft 81 is rotatably supported by the right side wall 382a of the rotating member 38. A hole 382c through which the operating shaft 81 is inserted is formed on the upper side of the right side wall 382a. The operating shaft 81 is arranged above the adjusting shaft 72, and arranged so that the axial center of the operating shaft 81 and the axial center of the adjusting shaft 72 are located in the same plane. The operating shaft 81 is supported by a base member 91 that is supported by the support member 73. The support member 73 and the base member 91 will be described later.

A first transmission gear 83 provided at an axially intermediate portion of the operating shaft 81 meshes with a second transmission gear 721 provided on the adjustment shaft 72. That is, the rotation direction of the rotation of the operating shaft 81, that is, the rotation of the first transmission gear 83 about the axis in the left-right direction is converted into the rotation of the second transmission gear 721 about the axis of the adjustment shaft 72.

In the chair 1 configured in this way, when adjusting the reaction force (returning force) of the backrest 20, first rotate the operating lever 82 of the operating section 80, and the spring rear end support of the compression coil spring 61 will be adjusted. An operating shaft 71 located at the portion 63 moves up and down along an adjustment shaft 72. For example, by rotating the operating lever 82 in one direction, the adjustment shaft 72 is rotated in one direction via the first transmission gear 83 and the second transmission gear 721, and the nut portion 711 that is screwed onto the adjustment shaft 72 is activated. The shaft 71 will move upward along the adjustment shaft 72.

In this way, by moving the action shaft 71 on the adjustment shaft 72, the distance between the spring front end support part 62 and the spring rear end support part 63 of the biasing part 60 changes, and the compression coil spring The amount of compression of the compression coil spring 61, that is, the biasing force (reaction force) of the compression coil spring 61 can be adjusted. That is, the return force when the backrest 20 returns from the tilted state to the initial state can be adjusted.

In addition, in the adjustment section 70 of this embodiment, by moving the operating shaft 71 on the adjusting shaft 72, the position of the operating shaft 71, that is, the position of the spring rear end support part 63 of the compression coil spring 61 is changed, and the compression coil is changed. This configuration adjusts the biasing force of the spring 61 (returning force of the backrest 20). In this embodiment, as shown in FIG. 12, mechanically, the operating shaft 71 that moves the adjustment shaft 72 can be adjusted to a position above the rotation main shaft 42 in the vertical direction.

As shown in FIG. 9, the first side support plate 734 and the second side support plate 735 of the support member 73 are a first side support plate 734 and a second side support plate 734 and a second side support plate each having a flat plate shape and whose plate surfaces face in the left-right direction. 735 are arranged at intervals in the width direction. In the first side support plate 734 and the second side support plate 735,

holes

734a and 735a that penetrate in the width direction are formed at positions facing each other in the width direction. A hole 734a formed in the first side support plate 734 is referred to as a first hole 734a, and a hole 735a formed in the second side support plate 735 is referred to as a second hole 735a.
The base member 91 is inserted into the first hole 734a and the second hole 735a. The base member 91 supports an operating section 80 (second operating member) of the return section 92 and an operating member 95 (first operating member) of the regulating section 93, which will be described later.

As shown in FIGS. 9 and 10, the base member 91 is a rod-shaped member, and its axis 91a extends in the left-right direction. The axis 91a of the base member 91 corresponds to the second axis of the present invention. The left end portion of the base member 91 protrudes to the left side of the first side support plate 734. The right end portion of the base member 91 protrudes to the right side of the second side support plate 735.
The intermediate portion of the base member 91 in the length direction (left and right direction) is referred to as an intermediate portion 911, the left side of the intermediate portion 911 is referred to as a first support portion 912, and the right side of the intermediate portion 911 is referred to as a second support portion 913. It is written as.

The cross-sectional shape of the intermediate portion 911 is circular. The cross-sectional shape of the first support portion 912 is circular, which is smaller than the cross-sectional shape of the intermediate portion 911 . A first step portion 914 is formed at the boundary between the intermediate portion 911 and the first support portion 912 , in which the outer periphery of the intermediate portion 911 projects further in the radial direction than the outer periphery of the first support portion 912 . The end face 911b on the right side (first support part 912 side) of the intermediate part 911 and the circumferential surface of the first support part 912 form a first step part 914.

The cross-sectional shape of the second support portion 913 is a rectangle with rounded corners. The square cross-sectional shape of the second support portion 913 has a size that is inscribed in the circular cross-sectional shape of the intermediate portion 911 . Therefore, a second step part 915 is formed at the boundary between the intermediate part 911 and the second support part 913, in which the outer periphery of the intermediate part 911 protrudes outward in the radial direction than the outer periphery of the second support part 913. . The end face 911c on the left side (second support part 913 side) of the intermediate part 911 and the circumferential surface of the second support part 913 form a second step part 915.

The left end 911a of the intermediate portion 911 of the base member 91 is inserted into the hole 734a of the first side support plate 734. The left end surface 911b of the intermediate portion 911 projects slightly to the left of the left side surface 734b of the first side support plate 734. That is, the right end surface 911b of the intermediate portion 911 is located slightly to the left of the left surface 734b of the first side support plate 734.
The first hole 734a is a round hole. The inner diameter of the first hole portion 734a is the same as or slightly larger than the outer diameter of the intermediate portion 911. The intermediate portion 911 inserted into the first hole 734a is rotatable around the axis 91a of the base member 91 with respect to the first side support plate 734. The first support part 912 is arranged on the left side of the first side support plate 734.
A portion of the base member 91 slightly to the right of the left end 913a of the second support portion 913 is inserted into the second hole portion 735a of the second side support plate 735. The boundary between the second support part 913 and the intermediate part 911 is arranged on the left side of the second side support plate 735, that is, on the first side support plate 734 side. The second hole portion 735a is a round hole. The inner diameter of the second hole portion 735a is larger than the outer diameter of the second support portion 913. The second support portion 913 inserted into the second hole portion 735a is rotatable around the axis 91a of the base member 91 with respect to the second side support plate 735.

The base member 91 is inserted into the first hole 734a of the first side support plate 734 and the second hole 735a of the second side support plate 735, and is rotated around the axis 91a of the base member 91 with respect to the support member 73. It can be rotated to
A first recess 736 and a second recess 737 are formed along the circumferential direction (direction around the axis 91a of the base member 91) at the upper edge of the first side support plate 734. The first recess 736 is arranged on the front side than the second recess 737. A protrusion 738 is formed between the first recess 736 and the second recess 737. The first recess 736 and the second recess 737 are configured so that a protrusion of a connecting member 94, which will be described later, fits therein.

As shown in FIGS. 11 and 12, the operating shaft 81 has a recess 811 formed in the left end portion 81a that extends in the left-right direction and opens to the left. A portion of the second support portion 913 of the base member 91 that protrudes to the right side of the second side support plate 735 is inserted into the recess 811 . The operating shaft 81 is not inserted into the second hole 735a of the second side support plate 735. The cross-sectional shape of the recessed portion 811 is the same as the cross-sectional shape of the second support portion 913, which is a rectangle. A second support portion 913 is fitted into the recess 811, and the operation shaft 81 and the second support portion 913, that is, the base member 91 are fixed so as not to rotate relative to each other around the axis 91a of the base member 91.

The operating shaft 81 is inserted into the hole 382c of the right side wall 382a of the rotating member 38 from the right side. The outer diameter of the left end portion 81a of the operating shaft 81 is smaller than the diameter of the hole 382c. The operating shaft 81 is formed with an enlarged diameter portion 812 that protrudes in the radial direction at a position to the right of the left end portion 81a. The outer diameter of the enlarged diameter portion 812 is larger than the diameter of the hole 382c. When the enlarged diameter portion 812 comes into contact with the right side surface of the side wall 382a while the operating shaft 81 is inserted into the hole 382c, it restricts the leftward displacement of the operating shaft 81.

A groove portion 813 is formed in the operating shaft 81 over the entire circumferential direction at a position to the right of the left end portion 81a and to the left of the enlarged diameter portion 812. A bearing member 814 is fitted into the groove portion 813. The bearing member 814 is a C-shaped member obtained by cutting out a part of an annular member, and can be fitted into the groove 813 of the operating shaft 81 from the outer circumferential side of the operating shaft 81. In this embodiment, the bearing member 814 can be fitted into the groove 813 of the operating shaft 81 from above. The bearing member 814 is provided with a flange 814a that projects outward in the radial direction at the right end.

The bearing member 814 is configured such that the operation shaft 81 is inserted into the hole 382c of the right side wall 382a of the rotating member 38 from the right side, and the enlarged diameter portion 812 is in contact with the right side surface of the side wall 382a or with a slight gap. , is fitted into the groove 813 of the operating shaft 81. In this embodiment, a rib protruding from the edge of the hole 382c to the right is provided on the right side surface of the side wall 382a, and the enlarged diameter portion 812 is in contact with the rib or with a slight gap therebetween. Placed. When the bearing member 814 is fitted into the groove 813 in this manner, the flange 814a is placed in contact with the left side surface of the side wall 382a or with a slight gap left therebetween. When the bearing member 814 comes into contact with the left side surface of the side wall 382a, it restricts the displacement of the operating shaft 81 to the right.
Note that even when at least one of the enlarged diameter portion 812 and the bearing member 814 is in contact with the side wall 382a, the operating shaft 81 can rotate around the axis with respect to the side wall 382a.
Displacement of the operating portion 80 in the left-right direction with respect to the rotating member 38 is restricted by the enlarged diameter portion 812 of the operating shaft 81 and the flange 814a.

As shown in FIGS. 12 and 13, the first transmission gear 83 includes a gear main body 831 in which a gear is formed, a gear fixing part 832 that is provided coaxially with the gear main body 831 and fixed to the base member 91. are doing. The first transmission gear 83 has an axis extending in the left-right direction, and is arranged such that the gear main body 831 is on the left side of the gear fixing part 832. A hole 833 is formed in the first transmission gear 83 and extends through the first transmission gear 83 in the axial direction. A portion of the hole 833 that passes through the gear body 831 is referred to as a first hole 833a, and a portion that passes through the gear fixing portion 832 is referred to as a second hole 833b. The first transmission gear 83 is arranged on the left side of the second side support plate 735.

The base member 91 is inserted into the hole 833 of the first transmission gear 83. A portion of the second support portion 913 of the base member 91 on the left side of the second side support plate 735 is fitted into the first hole portion 833a. The cross-sectional shape of the first hole 833a is a quadrilateral with rounded corners, which is the same as the cross-sectional shape of the second support portion 913. The right end portion of the intermediate portion 911 of the base member 91 is fitted into the second hole portion 833b. The cross-sectional shape of the second hole portion 833b is circular, which is the same as the cross-sectional shape of the intermediate portion 911.

The second support portion 913 of the base member 91 is inserted into the hole 833 of the first transmission gear 83 . The first transmission gear 83 and the base member 91 are fixed so as not to rotate relative to each other around the axis 91a of the base member 91. The first transmission gear 83 is inserted through the end portion of the second support portion 913 on the left side (the intermediate portion 911 side). As shown in FIG. 13, the left end surface 83a of the first transmission gear 83 is located at a second step portion 915 at the boundary between the intermediate portion 911 of the base member 91 and the second support portion 913 (see FIG. 9). and is close to the end surface 911c (see FIG. 9) on the left side (second support portion 913 side) of the intermediate portion 911 with a slight gap therebetween. As a result, when the base member 91 attempts to displace to the right with respect to the first transmission gear 83, that is, the operating unit 80, the left end surface 911c of the intermediate portion 911 of the base member 91 is displaced from the left end surface of the first transmission gear 83. 83a, and this displacement is regulated. The base member 91 is restricted from being displaced to the right with respect to the operating section 80 .

When the operating shaft 81 rotates around the axis 91a of the base member 91, the base member 91 also rotates together. When the base member 91 rotates around the axis 91a of the base member 91, it rotates together with the first transmission gear 83. That is, when the operating shaft 81 rotates around the axis 91a of the base member 91, the first transmission gear 83 also rotates together.
Since the base member 91 is rotatable around the axis 91a of the base member 91 relative to the support member 73, the support member 73 does not rotate even if the base member 91 rotates.

The regulating portion 93 shown in FIG. 14 regulates the rotation of the backrest 20 about the rotation main shaft 42, as described above. The regulating portion 93 includes an engaging member 96 having an engaging convex portion 961 that is inserted into any of the plurality of engaging recesses 44 provided in the support base 40, and an operating member 95 for operating the engaging member 96 (see FIG. 11 and FIG. 15)) and a connecting member 94 (see FIGS. 11 and 15) that connects the engaging member 96 and the operating member 95. As shown in FIGS. 11 and 15, the engaging member 96, the operating member 95, and the connecting member 94 are supported by the base member 91.

As shown in FIGS. 11 and 12, the operating member 95 is provided on the rotating member 38. As shown in FIGS. The operating member 95 includes an operating shaft 951 extending in the left-right direction and inserted into a hole 382d formed in the left side wall 382b, and an operating lever 952 connected to the left end of the operating shaft 951. There is.
The operating shaft 951 is rotatably supported by the left side wall 382b of the rotating member 38. A hole 382d through which the operating shaft 951 is inserted is formed on the upper side of the left side wall 382b.

The operating shaft 951 has a recess 953 formed in the right end portion 951a that extends in the left-right direction and opens to the right. The first support portion 912 of the base member 91 is inserted into the recess 953 . The right end surface 951b of the operating shaft 951 is close to the right end surface 911b (on the first support section 912 side) of the intermediate portion 911 of the base member 91 with a slight gap therebetween. As a result, when the base member 91 attempts to displace to the left with respect to the operation shaft 951, that is, the operation member 95, the right end surface 911b of the intermediate portion 911 of the base member 91 comes into contact with the right end surface 951b of the operation shaft 951. , this displacement is regulated. The left side displacement of the base member 91 with respect to the operating member 95 is restricted.
As described above, the right end surface 911b of the intermediate portion 911 is located slightly to the left of the left side surface 734b of the first side support plate 734. Therefore, a slight gap is formed between the right end surface 951b of the operating shaft 951 and the right end surface 911b of the intermediate portion 911.

The cross-sectional shape of the recess 953 is a circular shape that is the same as or slightly larger than the cross-sectional shape of the first support portion 912. The relative rotation of the operating shaft 951 and the first support portion 912 about the axis 91a of the base member 91 is not restricted. That is, the operating shaft 951 is supported by the base member 91 so as to be rotatable around the axis 91a of the base member 91.
The cross-sectional shape (outer shape) of the right end portion 951a of the operating shaft 951 in which the recess 953 is formed is a quadrilateral with rounded corners. The cross-sectional shape of a portion 951c on the left side of the right end portion 951a of the operating shaft 951 is circular. The rectangular cross-sectional shape of the right-hand operation shaft 951 has a size that is inscribed in the circle of the cross-sectional shape of the left-hand portion 951c.

As shown in FIG. 13, at the boundary between the right end portion 951a and the left portion 951c of the operating shaft 951, there is a groove in which the outer periphery of the left portion 951c protrudes radially more than the outer periphery of the right end portion 951a. A three-step portion 951d is formed. The right end surface 951e of the left portion 951c of the operating shaft 951 and the circumferential surface of the right end portion 951a form a third step portion 951d.
A protrusion 954 extending in the left-right direction is formed on the outer periphery of the right end portion 951a of the operation shaft 951.

The operating shaft 951 is inserted into the hole 382d of the left side wall 382b of the rotating member 38 from the left side. The outer diameter of the right end portion 951a of the operating shaft 951 is smaller than the diameter of the hole 382d. The operating shaft 951 has an enlarged diameter portion 955 that projects in the radial direction at a position to the left of the right end portion 951a. The outer diameter of the enlarged diameter portion 955 is larger than the diameter of the hole 382d. When the enlarged diameter portion 955 comes into contact with the left side surface of the side wall 382b while the operating shaft 951 is inserted into the hole 382d, it restricts the displacement of the operating shaft 951 to the right.

A groove portion 956 is formed in the operating shaft 951 over the entire circumferential direction at a position to the left of the right end portion 951a and to the right of the enlarged diameter portion 955. A bearing member 957 (see FIGS. 8 and 12) is fitted into the groove 956. The bearing member 957 is a C-shaped member obtained by cutting out a part of an annular member, and can be fitted into the groove 956 of the operating shaft 951 from the outer circumferential side of the operating shaft 951. In this embodiment, the bearing member 957 can be fitted into the groove 956 of the third step 951d from above. The bearing member 957 is provided with a flange 957a that projects outward in the radial direction at the left end.

The bearing member 957 is configured such that the operation shaft 951 is inserted into the hole 382d of the left side wall 382b of the rotating member 38 from the left side, and the enlarged diameter portion 955 is in contact with the left side surface of the side wall 382b or with a slight gap. , is fitted into the groove 956 of the operating shaft 951. In this embodiment, a rib protruding from the edge of the hole 382d to the right is provided on the left side surface of the side wall 382b, and the enlarged diameter portion 955 is in contact with the rib or with a slight gap therebetween. Placed. When the bearing member 957 is fitted into the groove 956 in this manner, the flange 957a is placed in contact with the right side surface of the side wall 382b or with a slight gap therebetween. When the bearing member 957 comes into contact with the right side surface of the side wall 382b, it restricts the displacement of the operating shaft 951 to the left.
Note that even when at least one of the enlarged diameter portion 955 and the bearing member 957 is in contact with the side wall 382b, the operating shaft 951 can rotate around the axis with respect to the side wall 382b.
The operation member 95 is restricted from being displaced in the left-right direction with respect to the rotating member 38 by the enlarged diameter portion 955 of the operation shaft 951 and the flange 957a.

As shown in FIG. 11, FIG. 12, FIG. 15, and FIG. , and a third connecting portion 943 provided between the first connecting portion 941 and the second connecting portion 942. The first connecting portion 941, the second connecting portion 942, and the third connecting portion 943 are integrally formed. The connecting member 94 includes a first connecting portion 941, a third connecting portion 943, and a second connecting portion 942, which are arranged in this order from left to right. The connecting member 94 is rotatable relative to the base member 91 around the axis 91a of the base member 91.

The first connecting portion 941 has a cylindrical shape and is arranged in a direction in which the hole portion 941a penetrates in the width direction. The cross-sectional shape of the hole 941a of the first connecting portion 941 is the same as the outer shape of the right end portion of the operating shaft 951, and is a quadrilateral with rounded corners. A groove 941b corresponding to the protrusion 954 of the operating shaft 951 is formed on the inner peripheral surface of the hole 941a. The right end portion 951a of the operating shaft 951 is fitted into the hole 941a of the first connecting portion 941. The protrusion 954 of the operating shaft 951 is inserted into the groove 941b of the hole 941a of the first connecting portion 941. The operating shaft 951 and the first connecting portion 941 do not rotate relative to each other. That is, the connecting member 94 is fixed to the operating shaft 951 and does not rotate relative to the operating shaft 951 and the base member 91 around the axis 91a. The first support portion 912 of the base member 91 is inserted into the hole 941 a of the first connection portion 941 . The first connecting portion 941 is rotatable relative to the base member 91 around the axis 91 a of the base member 91 .

The left end surface 941c of the first connecting portion 941 is located at the third step portion 951d (see also FIG. 13) at the boundary between the right end portion 951a of the operating shaft 951 and the left portion 951c. As shown in FIG. 15, a portion 941d of the left end surface 941c of the first connecting portion 941 shown in FIG. It comes into contact with the right end surface 951e (see also FIG. 13) of 951c. The right end surface 951e of the left portion 951c of the operating shaft 951 is a surface facing right that forms the third step portion 951d. Thereby, the first connecting portion 941, that is, the connecting member 94 is restricted from being displaced to the left with respect to the operating shaft 951.

The second connecting portion 942 has a cylindrical shape and is arranged in a direction in which the hole 942a penetrates in the width direction. The cross-sectional shape of the hole 942a of the second connecting portion 942 is circular, which is the same as or slightly larger than the cross-sectional shape of the intermediate portion 911 of the base member 91. The intermediate portion 911 is inserted into the hole 942a of the second connecting portion 942. The second connecting portion 942 is rotatable relative to the base member 91 around the axis 91a of the base member 91.

The first transmission gear 83 is arranged on the right side of the second connecting portion 942, that is, on the right side of the connecting member 94. As mentioned above, the first transmission gear 83 is fixed to the base member 91. When the connecting member 94 attempts to displace to the right with respect to the base member 91, it comes into contact with the first transmission gear 83, and therefore is restricted from displacing to the right. Note that a slight gap is provided between the right end surface of the connecting member 94 and the left end surface 83a of the first transmission gear 83 to allow relative rotation between the connecting member 94 and the base member 91. ing.

The third connecting portion 943 is rotatable relative to the base member 91 around the axis 91a of the base member 91. The third connection part 943 includes a first plate part 943a arranged on the left side of the first side support plate 734 and connected to the first connection part 941, and a second connection part 943a arranged on the right side of the first side support plate 734. It has a second plate part 943b that is connected to the section 942, and a connecting part 943c that connects the first plate part 943a and the second plate part 943b.
The connecting portion 943c is arranged above the first side support plate 734. A convex portion 943d that protrudes downward is formed on the lower surface (the surface facing the first side support plate 734) of the connecting portion 943c.
As shown in FIG. 17, when the connecting portion 943c rotates around the axis 91a of the base member 91, the convex portion 943d is placed in either the first recess 736 or the second recess 737 of the first side support plate 734. be done. In FIG. 17, the connection member 94 in which the convex portion 943d is arranged in the second concave portion 737 is indicated by a chain double-dashed line. The convex portion 943d is elastically deformed when climbing over the convex portion 738 between the first concave portion 736 and the second concave portion 737. In this embodiment, the convex portion 943d has a slit 943e extending in the direction of the axis 91a of the base member 91, and has two

elastic pieces

943f, 943f in front and behind the slit 943e. Thereby, the convex portion 943d easily deforms elastically when climbing over the convex portion 738.

When the operating member 95 is operated and rotates around the axis 91a of the base member 91, the connecting member 94 also rotates together with the operating member 95. The operation member 95 stops rotating at either the position where the protrusion 943d of the connection member 94 fits into the first recess 736 or the position where it fits into the second recess 737.

The engaging member 96 shown in FIGS. 14, 17, and 18 is a leaf spring. As shown in FIG. 17, when the protrusion 943d of the connecting member 94 to be connected is fitted into the first recess 736, the engagement member 96 is oriented such that the engagement protrusion 961 is inserted into the engagement recess 44. When the protrusion 943d fits into the second recess 737, the engagement protrusion 961 is urged in the direction of being ejected from the engagement recess 44.

As shown in FIG. 18, the engaging member 96 extends diagonally from the front toward the rear and gradually upward. The engagement member 96 is rotatably supported around the axis by a shaft portion 962 having an axis extending in the left-right direction at an intermediate portion in the height direction. The axis 962a of the shaft portion 962 that supports the engaging member 96 corresponds to the third axis of the present invention. The axis 962a of the shaft portion 962 is located below the axis 91a of the base member 91.
The shaft portion 962 is supported by the rotating member 38. That is, the shaft portion 962 is supported by the backrest 20. The shaft portion 962 is located below the axis 91a of the base member 91 and above the engagement recess 44. The upper part of the engagement member 96 is curved forward. A foundation support portion 965 is provided at the upper end of the engagement member 96 and is connected to the second connection portion 942 of the connection member 94 via a link portion 963. An engagement protrusion 961 is provided at the lower end of the engagement member 96 .

The link portion 963 protrudes in the radial direction from the outer circumferential surface of the second connecting portion 942. The link portion 963 protrudes further than the operating member 95 in the radial direction (the direction intersecting the second shaft portion). The link portion 963 has a link shaft portion 963a at its tip. The link shaft portion 963a has a cylindrical shape, and its axis extends in the left-right direction. A link shaft portion 963a is inserted into the base support portion 965 at the upper end of the engagement member 96 in the left-right direction. The base support portion 965 and the link shaft portion 963a are relatively rotatable around the axis of the link shaft portion 963a.
The link portion 963 rotates around the axis 91a of the base member 91 together with the connecting member 94 when the operating member 95 is operated. The base support portion 965 (engaging member 96) rotates around the axis 91a of the base member 91 together with the link shaft portion 963a. Since the engagement member 96 is rotatably supported by the shaft portion 962, the base support portion 965 rotates around the axis 91a of the base member 91 together with the link shaft portion 963a, and rotates around the axis of the link shaft portion 963a. Rotate relative to.
The link portion 963 functions as an interlocking portion that transmits the operating force input to the operating member 95 to the engaging member 96 and causes the engaging member 96 to interlock with the operating member 95.

As shown in FIG. 17, when the convex portion 943d of the connecting member 94 is fitted into the first concave portion 736, the link portion 963 is located forward (indicated by a solid line in FIG. 17), and the convex portion 943d of the connecting member 94 is positioned forward. When fitted into the second recess 737, the link portion 963 is positioned at the rear (indicated by a two-dot chain line in FIG. 17). As a result, when the protrusion 943d is fitted into the first recess 736, the engagement protrusion 961 at the lower end of the engagement member 96 is positioned further back than when the protrusion 943d is fitted into the second recess 737. When the engagement protrusion 961 moves backward, it is inserted into the engagement recess 44 (indicated by a solid line in FIG. 17), and when it moves forward, it is removed from the engagement recess 44 (indicated by a two-dot chain line in FIG. 17).
A state in which the protrusion 943d of the connecting member 94 fits into the first recess 736 and the engagement protrusion 961 is inserted into the engagement recess 44 is referred to as a locked state. A state in which the engagement convex portion 961 is projected from the engagement recess 44 is referred to as a disengaged state.

The engagement protrusion 961 is inserted into a hole 383 provided in the rear wall 381 of the rotating member 38. The engagement convex portion 961 does not come out of the hole 383 and is always inserted into the hole 383. The hole 383 is located forward and above the engagement recess 44 . When the rear side of the engagement protrusion 961 protrudes rearward from the hole 383, it is inserted into the engagement recess 44 (shown by a solid line in FIGS. 17 and 18), and the rear side enters the hole 383. It comes out of the recess 44 (indicated by a two-dot chain line in FIGS. 17 and 18). In the detached state, the engagement recess 44 and hole 383 are in a misaligned state.
When a load is applied to the backrest 20 and the rotating member 38 is displaced, the engaging convex portion 961 is displaced along with this displacement, or an external force acts on the engaging convex portion 961 in the direction in which the rotating member 38 is displaced.

When the operating member 95 is operated from the detached state to the locked state, the convex portion 943d of the connecting member 94 moves from the second recess 737 to the first recess 736. At this time, the upper side of the shaft part 962 of the engaging member 96 moves to the front side and becomes the state shown by the solid line in FIGS. 17 and 18, but the lower side of the shaft part 962 moves to the front side. Since it is not inserted into the engagement recess 44, it remains in the detached state shown by the two-dot chain line in FIGS. 17 and 18. At this time, the engagement member 96 is elastically deformed and is urged in the direction in which the engagement protrusion 961 enters the engagement recess 44 .

In this state, when the backrest 20 rotates around the axis 42a of the rotation main shaft 42 and the engagement recess 44 overlaps the hole 383, the engagement protrusion 961 is inserted into the engagement recess 44, resulting in a locked state. . At this time, the elastic deformation of the engaging member 96 is restored, and the biasing force is reduced or eliminated.

In the locked state, the axis of the hole 383 and the axis of the engagement recess 44 are misaligned, and external forces are received from the side surface of the hole 383 (rotating member 38) and from the side surface of the engagement recess 44 (support base 40). If the shearing force is applied to the engagement protrusion 961 so that it is sandwiched between the side surface of the hole 383 and the side surface of the engagement recess 44, even if the upper side of the engagement member 96 moves forward, The engagement convex portion 961 becomes stuck in the engagement recess 44.
When the operating member 95 is operated to change from the locked state to the detached state, the convex portion 943d of the connecting member 94 moves from the first recess 736 to the second recess 737. At this time, the upper side of the shaft part 962 of the engaging member 96 moves rearward and becomes the state shown by the two-dot chain line in FIGS. 17 and 18, but the lower side of the shaft part 962 moves to the rear side. The convex portion 961 cannot be removed from the engagement recess 44 and remains in the locked state shown by the solid line in FIGS. 17 and 18. At this time, the engagement member 96 is elastically deformed and is urged in the direction in which the engagement convex portion 961 comes out of the engagement recess 44 .

When the backrest 20 moves in this state and the engagement recess 44 overlaps the hole 383, the engagement protrusion 961 comes out of the engagement recess 44 and enters the detached state. At this time, the elastic deformation of the engaging member 96 is restored, and the biasing force is reduced or eliminated.

As described above, the operation unit 80 is restricted from being displaced in the left-right direction with respect to the rotating member 38. The operation member 95 is restricted from being displaced in the left-right direction with respect to the rotation member 38 . The base member 91 is restricted from being displaced to the right with respect to the operating section 80 . The left side displacement of the base member 91 with respect to the operating member 95 is restricted. The connecting member 94 is restricted from being displaced to the left with respect to the operating shaft 951. The connecting member 94 is restricted from being displaced to the right with respect to the base member 91.
With the above configuration, displacement of the engaging member 96 connected to the connecting member 94 in the left-right direction with respect to the rotating member 38 is restricted. That is, the above configuration functions as a position alignment mechanism in the left-right direction between the engagement protrusion 961 of the engagement member 96 and the engagement recess 44 provided in the rotating member 38.

Next, the functions and effects of the above-mentioned chair will be explained using the drawings.
In the chair 1 according to the present embodiment described above, the operating member 95 (first operating member) of the regulating section 93 is supported on the left side of the base member 91, and the operating member 80 (second operating member) of the return section 92 is supported on the right side of the base member 91. members) are supported. As a result, the seated person can operate the restriction part 93 with his left hand while seated, and operate the return part 92 with his right hand without changing his posture, resulting in good operability. In particular, by providing the operating member 95 and the operating portion 80 on the backrest 20, the seated person can operate the backrest 20 at a position close to the backrest 20.
Furthermore, interference between the operating member 95 and the operating section 80 can be prevented. Furthermore, since the operating member 95 and the operating section 80 can be provided together via the base member 91, unitization is easy and workability during assembly is good.

Further, in the chair 1 according to the present embodiment, the base member 91 has a rod shape extending in the width direction.
With such a configuration, the space occupied by the base member 91 can be reduced, and a large space can be secured for arranging other members such as the regulating portion 93 and the return portion 92.

Further, in the chair 1 according to the present embodiment, the base member 91 is a shaft portion having an axis 91a (second axis) extending in the width direction, and the operation member 95 and the operation portion 80 are arranged on the axis 91a of the base member 91. arranged coaxially.
With this configuration, the base member 91, the operating member 95, and the operating section 80 are arranged side by side in the width direction, so that the space occupied by these members can be reduced.

In the chair 1 according to the present embodiment, the return unit 92 includes a compression coil spring 61 that biases the backrest 20 in a tilted state in a direction to return to the initial state, and a compression coil spring 61 that is linked to the operating unit 80. It has an adjustment section 70 that adjusts the biasing force. The base member 91 is rotatable around the axis 91 a of the base member 91 , the operating member 95 is relatively rotatable around the axis 91 a of the base member 91 and the base member 91 , and the operating unit 80 is connected to the base member 91 . The base member 91 is fixed relatively unrotatably around the axis 91a.
With such a configuration, the operating force of the operating section 80 can be directly transmitted to the compression coil spring 61.

Further, in the chair 1 according to the present embodiment, the rotating member 38 of the backrest 20 has two

side walls

382a and 382b arranged with an interval left and right, and the operating member 95 of the regulating part 93 is located on the left side. It is supported by the side wall 382a, and the operation part 80 of the return part 92 is supported by the right side 382b.
With such a configuration, the operating member 95 and the operating section 80 are arranged in a dispersed manner in the width direction, so that the operating member 95 and the operating section 80 are both arranged on one side in the left-right direction. Compared to the case, it is possible to prevent the seated person from accidentally operating the operating member 95 and the operating section 80.

Further, in the chair 1 according to the present embodiment, the regulating portion 93 and the returning portion 92 are arranged at positions with the base member 91 sandwiched therebetween when viewed from the width direction.
With such a configuration, the regulating portion 93 and the returning portion 92 can be arranged at positions where they do not interfere with each other.

Furthermore, in the chair 1 according to the present embodiment, the base member 91 has an intermediate portion 911 between the first support portion 912 and the second support portion 913, and both ends of the intermediate portion 911 in the width direction are attached to the chair 1. It is supported by a first side support plate 734 and a second side support plate 735 (two collars) provided.
With such a configuration, the base member 91 is reliably supported by the chair 1, and the operating member 95 and the operating section 80 supported by the base member 91 can be operated in a stable state.

Although the embodiments of the chair according to the present invention have been described above, the present invention is not limited to the above embodiments, and can be modified as appropriate within the scope.
For example, in the above embodiment, the base member 91 is provided on the backrest 20, but it may be provided on a member of the chair 1 other than the base member 91, such as the support base 40 or the seat 17.
Further, in the chair 1 according to the present embodiment, the base member is in the shape of a rod extending in the width direction, but may be in the shape of a plate or block, or may be a member extending in the front-rear direction.

Furthermore, in the chair 1 according to the present embodiment, the base member is a shaft portion having an axis 91a extending in the width direction, and the operating member 95 and the operating portion 80 are arranged coaxially on the axis 91a of the base member 91. However, the axis may be disposed at a position shifted from the axis. The operating member 95 and the operating section 80 may be configured to be operated by sliding instead of rotating.

Further, in the chair according to the present embodiment, the operating member 95 of the regulating section 93 is relatively rotatable around the axis 91a between the base member and the base member 91, and the operating member 80 of the return section 92 is able to rotate between the base member and the base member 91. The operating member 95 is fixed relative to the axis 91a of the base member and the base member 91 so as not to rotate relative to each other. It may be relatively rotatable around the axis 91a. Both the one operating member and the operating section 80 may be relatively rotatable around the axis 91a of the base member and the base member 91.

Further, in the chair according to the present embodiment, the regulating part 93 and the returning part 92 are arranged at positions with the base member 91 sandwiched between them when viewed from the width direction, but the arrangement of the regulating part 93 and the returning part 92 is It may be set as appropriate.

Further, in the chair 1 according to the present embodiment, the operating member 95 of the regulating section 93 is supported by the left side wall 382a, and the operating section 80 of the return section 92 is supported by the right side wall 382b. The configuration in which the operation unit 80 is supported by the chair 1 may be other than the above.

Furthermore, in the chair according to the present embodiment, the base member 91 is supported by the first side support plate 734 and the second side support plate 735, but the form in which the base member 91 is supported may be set as appropriate.

1 Chair 17 Seat 20 Backrest 40 Support base (support structure)
42a Axis line (first axis line)
60 Biasing part 61 Compression coil spring (spring)
70 Adjustment section 80 Operation section (second operation member)
91 Foundation member 91a axis (second axis)
92 Return part 93 Regulation part 95 Operation member (first operation member)

382a Side wall

382b Side wall 734 First side support plate (flange)
735 Second side support plate (flange)
911 Intermediate portion 912 First support portion 913 Second support portion 962 Shaft portion

Claims

a support structure;
a backrest rotatably supported by the support structure around a first axis extending in the width direction of the support structure and movable from an initial state to a tilted state tilted rearward;
a regulating part that regulates rotation of the backrest about the first axis;
a return unit that returns the backrest in the tilted state to the initial state;
a first operating member for a seated person to operate the regulating portion;
a second operating member for the seated person to operate the return portion;
a base member that supports the first operating member and the second operating member;
The base member extends in the width direction,
The first operation member is supported by a first support portion provided at one end side of the base member in the width direction,
The second operating member is a chair supported by a second support portion provided at the other end of the base member in the width direction.
The chair according to claim 1, wherein the base member has a rod shape extending in the width direction.
The base member is a shaft portion having a second axis extending in the width direction,
The chair according to claim 2, wherein the first operating member and the second operating member are coaxially arranged on the second axis.
The return section is
a spring that biases the backrest in the tilted state in a direction to return to the initial state;
an adjustment section that is linked to the second operating member and adjusts the biasing force of the spring;
The base member is rotatable about the second axis,
The first operating member is rotatable relative to the base member about the second axis,
The chair according to claim 3, wherein the second operating member is fixed to the base member so as not to rotate relative to the second axis.
The chair according to any one of claims 1 to 4, wherein the regulating part and the returning part are arranged at positions sandwiching the base member between them when viewed from the width direction.
The backrest has two side walls spaced apart in the width direction,
The first operating member is supported by a side wall disposed on one side in the width direction,
The chair according to claim 5, wherein the second operating member is supported by a side wall disposed on the other side in the width direction.
The base member has an intermediate part between the first support part and the second support part,
The chair according to any one of claims 1 to 6, wherein both ends of the intermediate portion in the width direction are supported by two flanges provided on the chair.