JP5636230B2 - Backrest deflection adjustment mechanism - Google Patents

Description

  The present invention relates to a backrest deflection adjustment mechanism. More specifically, the present invention relates to a backrest deflection adjustment mechanism suitable for application to, for example, an office chair having a seat and a backrest.

  As an office chair having a seat and a backrest, for example, as shown in FIG. 13, a seat 104 supported by a base frame 103 attached to the top of a leg column 102 of a leg 101, and a front end of the base frame 103 There is one having a backrest 106 attached to the upper end of an inverted L-shaped back support rod 105 that is supported (Patent Document 1).

  As an office chair having a seat and a backrest, the backrest is made of a belt-like frame member that constitutes the peripheral portion, and a tension member that is made of a sheet material such as a knitted fabric and is stretched in the frame member (Patent Document 2).

JP-A-7-255562 JP 2007-117537 A

  However, the backrests of Patent Documents 1 and 2 do not deform the back plate and the back frame itself that constitute the backrest. Therefore, although the back width (in other words, the shoulder width) and the curvature of the back surface (in other words, the degree of rearward protrusion in the cross-sectional shape of the back) vary among individuals, the backrest of Patent Document 1 is used. Then, since the back plate does not deform, the curvature of the cross-sectional shape of the back plate (in other words, the amount of bending backward) is constant, so that the entire back is supported by the backrest. Even if the seated person wants to obtain the right angle, the cross-sectional shape cannot be adjusted, and there is a problem that it is difficult to say that the use of the backrest is comfortable.

  In addition, in the backrest of Patent Document 2, when a person with a light weight leans against the backrest, the tension member in the back frame slightly bends backward, while a heavy person leans against the backrest. In some cases, the upholstery material greatly bends backwards, so the amount of backward deflection of the cross-sectional shape of the backrest cannot be adjusted according to the individual preference of the seated person, and the use of the backrest is comfortable It is difficult to say.

  In view of the above, an object of the present invention is to provide a backrest deflection amount adjusting mechanism capable of adjusting the rearward deflection amount of the cross-sectional shape of the backrest.

In order to achieve this object, a backrest deflection adjustment mechanism according to claim 1 is a chair having a backrest that is supported by a pair of left and right back frames and has a back plate or back frame that is elastically deformable. The back frame or the back frame is bent by bending the back plate or the back frame by applying a lateral force to the back plate or the back frame by swinging the back frame. .

Further, the backrest deflection amount adjusting mechanism according to claim 5, wherein, in the chair with a backrest comprises an elastically deformable back plate or the back frame while being supported by a back frame extending in the lateral direction, the back plate or the back The frame is supported so that the left and right sides of the back of the back plate or the back frame can be rotated axially above the middle position of the back plate or the back frame by the vertical axis provided in the left and right connecting mechanism provided on the back frame, by bending the back plate or the back frame by adding longitudinal force to the right and left middle portion of the back plate or the back frame by a pressing mechanism provided on the back frame at the same vertical position as the left and right coupling mechanism, the back plate or the back The amount of bending backward of the frame is adjusted.

  Therefore, according to these backrest deflection amount adjustment mechanisms, it is possible to change the rearward deflection amount of the cross-sectional shape of the back plate / back frame according to the preference of the seated person or to adjust to the body shape. .

  According to a second aspect of the present invention, in the back deflection adjustment mechanism according to the first aspect, the back plate or the back frame is supported via a coupling mechanism provided on each of the pair of left and right back frames. The pair of left and right back frames are supported by the vertical axis of the coupling mechanism so as to be rotatable. In this case, since the degree of freedom of shaft rotation in the support portion is ensured, stress does not concentrate on the support portion when the back plate or back frame is deformed, and the back plate or back frame is smoothly deformed. It becomes easy to do.

  According to a third aspect of the present invention, in the back deflection adjustment mechanism according to the first aspect, the pair of left and right back frames is provided above the middle position of the back plate or the back frame above the middle position of the back plate or the back frame. The left and right sides are supported. In this case, the back plate or the back frame can be easily deformed.

According to a fourth aspect of the present invention, there is provided a backrest bending amount adjusting mechanism which is supported by a pair of left and right back frames and is operated by operating an operating portion in a chair having a backrest having a back plate or a back frame which is elastically deformable. When the pair of left and right back frames move in the left and right direction, a lateral force is applied to the back plate or the back frame to bend the back plate or the back frame, thereby adjusting the amount of backward bending of the back plate or the back frame. I am doing so. With this configuration, by moving the back frame itself, a lateral force is applied to the back plate / back frame to deform and flex the back plate / back frame.

  According to the back and forth deflection amount adjusting mechanism according to claims 1 and 5, the amount of backward deflection of the cross-sectional shape of the back plate / back frame can be changed according to the preference of the seated person or adjusted to the body shape. Therefore, it is possible to improve the comfort of use by leaning on the backrest.

  Furthermore, according to the backrest deflection adjustment mechanism according to claim 2, it is possible to prevent stress from being concentrated on the support portion of the back plate when the back plate is deformed. As a result, the product life can be extended and the back plate can be smoothly deformed, so that it is possible to further improve usability and comfort.

  Furthermore, according to the back deflection adjustment mechanism of the third aspect, the back plate or the back frame can be easily deformed, so that the operability and ease of use can be improved.

  According to the back deflection adjustment mechanism of the fourth aspect, by moving the back frame itself, a lateral force is applied to the back plate / back frame to deform and flex the back plate / back frame. be able to.

It is a side view which shows an example of embodiment of the backrest bending amount adjustment mechanism of this invention (state where the amount of back bending of the cross-sectional shape of a backplate is small). It is a figure which shows an example of embodiment of the backrest bending amount adjustment mechanism of this invention, and is a figure which shows the state with the small amount of bending to the back of the cross-sectional shape of a backplate. (A) is a top view of a back board. (B) is a back view of a back plate and a back frame support member / back frame. It is a figure which shows an example of embodiment of the backrest deflection amount adjustment mechanism of this invention, and is a figure which shows the state with the large deflection amount to the back of the cross-sectional shape of a backplate. (A) is a top view of a back board. (B) is a back view of a back plate and a back frame support member / back frame. It is a partially expanded side view of the backrest deflection adjustment mechanism of the embodiment. It is a disassembled rear view of the backrest bending amount adjusting mechanism (configuration with the back frame as the center in the rear portion) of the embodiment. It is a disassembled rear view of the backrest bending amount adjusting mechanism (configuration with the back frame support member as the center in the front portion) of the embodiment. It is a partially expanded view which shows the connection mechanism of the back frame and back plate in embodiment. (A) is a side view of a connection mechanism. (B) is a top view of a connection mechanism. It is a partially expanded view which shows the link member which connects the seat receiving member and back plate in embodiment. It is a figure which shows 2nd embodiment of the backrest deflection amount adjustment mechanism of this invention. It is a figure which shows 3rd embodiment of the backrest deflection amount adjustment mechanism of this invention. It is a figure which shows 4th embodiment of the backrest deflection amount adjustment mechanism of this invention. It is a figure which shows 5th embodiment of the backrest deflection amount adjustment mechanism of this invention. It is a figure which shows the conventional backrest.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  1 to 8 show an example of an embodiment of the backrest deflection adjustment mechanism of the present invention. In the present embodiment, the backrest deflection adjustment mechanism of the present invention will be described as an example when applied to a chair 20 whose overall structure is shown in FIG. Further, in the present specification, vertical, front / rear, and left / right are defined based on a seated person sitting on the seat 12 of the chair 20.

  The chair 20 according to the present embodiment includes a leg 21 having casters, a base frame 8 attached to and supported by the top of the leg column 21a of the leg 21, and a front end portion attached to a rear portion of the base frame 8 so as to be swingable. The back frame supporting member 1 is supported by the seat receiving member 11, the seat receiving member 11 having the front portion connected to the front end of the base frame 8 and the back frame supporting member 1 and the rear portion being connected. A seat 12, a back frame 5 to which a lower portion is attached to a rear end portion of the back frame support member 1, an upper portion supported by an upper end portion of the back frame 5, and a link to a rear end portion of the seat receiving member 11 And a back plate 2 to which a lower end portion is connected via a member 3. 2 and 3, members that are not related to the configuration of the back plate 2, the back frame support member 1, and the back frame 5 are not shown.

  Although not shown in the present embodiment, a cushion material may be attached to the front surface of the back plate 2, and a cover that covers at least the edge portion of the cushion material and the back plate 2 is further provided. Also good.

  The base frame 8, the seat receiving member 11, and the back frame support member 1 (1a, 1b) are configured to have a pair of left and right plate-like members as side walls.

  In the base frame 8, a rear end portion 8a having a bottom plate for connecting the left and right side walls is attached to the upper end of the leg column 21a by, for example, bolt coupling or taper fitting.

  The rear portion of the base frame 8 and the front end portion of the back frame support member 1 are connected so as to be swingable by a left and right swing shaft 8d penetrating the left and right side walls. The frame 5 can be locked.

  The back frame support member 1 includes an inclined member 1a extending obliquely upward and rearward from a front end portion connected to the base frame 8, a lower end portion coupled to a rearward portion of the inclined member 1a, and a seat 12 and a back plate 2 And an upright member 1b disposed in the up-down direction.

  Through holes 8b in the front-rear direction are formed in the front end portions of the left and right side walls of the base frame 8, and the base frame 8 is formed by a left-right swing shaft 8c that slidably passes through the through-hole 8b in the front-rear direction. The front end portion of the seat receiving member 11 and the front portion of the seat receiving member 11 are connected to be swingable. The swing shaft 8c is gripped and supported by a bearing 11a formed on the seat receiving member 11.

  Further, the intermediate portion of the inclined member 1a of the back frame support member 1 and the rearward portion of the seat receiving member 11 are connected so as to be swingable by a swing shaft 1c in the left-right direction penetrating these left and right side walls.

  Between the base frame 8 and the back frame support member 1, the front end is fixed to the intermediate portion of the base frame 8, and the rear end is at the front end (lower end) of the back frame support member 1 (inclined member 1 a). A reaction force mechanism 13 that is swingably connected via a connecting pin in the left-right direction is interposed. In the present embodiment, a compression coil spring is provided as a reaction force mechanism 13 in a compressed state in the front-rear direction. Then, by the reaction force mechanism 13, the front end portion of the back frame support member 1 is always urged obliquely downward and rearward, and the state where the back plate 2 is erected through the back frame 5 is maintained.

  Further, between the base frame 8 and the back frame support member 1, a front end portion is connected to a rear end portion of the base frame 8 via a connecting pin in the left-right direction so as to be swingable, and a rear end portion is connected to the back frame. A tilt adjustment mechanism 15 that is swingably connected via a connecting pin in the left-right direction is interposed in an intermediate portion of the support member 1 (a portion closer to the rear of the tilt member 1a). In the present embodiment, a gas spring with a telescopic lock mechanism is provided in the front-rear direction as the tilt adjustment mechanism 15.

  The tilt adjustment mechanism 15 constitutes a triangular link mechanism together with the base frame 8 and the back frame support member 1 (inclination member 1a), and when the length of the tilt adjustment mechanism 15 can be changed (that is, in a stretch-free state). While the back frame support member 1 can swing with respect to the base frame 8, when the length of the tilt adjustment mechanism 15 is fixed (that is, in a telescopic lock state), the back frame support member 1 is relative to the base frame 8. It cannot swing. That is, by switching between the variable length and fixed length of the tilt adjustment mechanism 15, the back plate 2 can be locked after adjusting the front / rear tilt angle. Note that the length of the tilt adjustment mechanism 15 is variable and fixed, in other words, switching between the telescopic free state and the telescopic lock state is performed by operating a lever (not shown). Various conventional mechanisms for operating the tilt adjustment mechanism 15 by the lever can be used. Since this mechanism is a well-known technique, the details thereof are omitted here.

  Further, in the present embodiment, the seat receiving member 11 and the seat 12 are connected by the elastic support member 12a arranged at positions near the four corners in the plan view of the seat 12 and the connection support mechanism 12b arranged in the center in the plan view. Has been.

  The connection support mechanism 12b is structured such that the seat receiving member 11 and the seat 12 are connected to each other so as to be tiltable in the front-rear and left-right directions by four swing shaft pins arranged in the front-rear and right-and-left directions. It is a mechanism having the same configuration as the connecting mechanism 6 described later). That is, in this embodiment, a universal joint is used as the connection support mechanism 12b. However, the present invention is not limited to the universal joint, and may be a pivot bearing, a ball joint, or the like, or may be supported so as to be tiltable using deformation of an elastic body such as a coil spring or a rubber block. In this embodiment, the oscillating shaft pins are arranged in the front-rear direction and the left-right direction, but the direction of arrangement of the oscillating shaft pins is not limited to this.

  With this structure, in this embodiment, the seat 12 can be tilted forward and left and right with respect to the seat support member 11 with the connection support mechanism 12b as a fulcrum, and the seat 12 is in a horizontal state when no load is applied, for example. It is supported to be stable. On the other hand, a convex portion 12c that protrudes downward is formed at the rear end portion of the lower surface of the seat 12 so that the convex portion 12c does not tilt backward when the convex portion 12c comes into contact with the rear end portion of the upper surface of the seat receiving member 11. It has become. However, the structure which does not provide the convex part 12c may be sufficient.

  In the present embodiment, the lower portion of the back plate 2 is connected to the rear portion of the seat receiving member 11 via the link member 3. As shown in FIG. 8, the link member 3 has an elongated plate shape and is formed with through holes at both ends in the longitudinal direction. One end of the link member 3 is a seat receiving member 11 via a connecting pin 3a in the left-right direction that penetrates the through hole. The other end is slidably connected to the lower part of the back plate 2 via a connecting pin 3b in the left-right direction penetrating the rear portion and penetrating the through hole. In the present embodiment, the link members 3 are arranged on the left and right sides of the seat receiving member 11 so as to be provided in a pair of left and right, but the number of link members 3 is not limited to two, for example, Further, one more may be provided at the left and right center of the back plate 2 and a total of three may be provided, or only one may be provided at the left and right center of the back plate 2.

  On the other hand, a back plate connecting portion 11 b is provided at the rear end portions of the left and right side walls of the seat receiving member 11. In the present embodiment, the back plate connecting portion 11b is formed in a plate shape that bends upward from behind from the rear end portions of the left and right side walls of the seat receiving member 11. And a through-hole is formed in the back upper end part of the backplate connection part 11b. In FIG. 8, members not related to the configuration associated with the link member 3 are not shown.

  Further, plate-like link connecting portions 2c projecting forward are provided at both left and right ends of the lower end portion of the front surface of the back plate 2, and through holes are formed in the link connecting portions 2c. In addition, the link connection part 2c may be integrally formed with the back plate 2, or may be configured by attaching a metal fitting to the back plate 2, for example.

  The link member 3 is formed in an elongated plate shape, and through holes are formed at both ends in the longitudinal direction. Then, one end (front end) of the link member 3 is rocked with respect to the seat receiving member 11 by the connecting pin 3a in the left-right direction passing through the through hole of the link member 3 and the through hole of the back plate connecting portion 11b of the seat receiving member. The back plate 2 is connected to the back plate 2 by a left and right connecting pin 3b that is movably connected and the other end (rear end) of the link member 3 passes through the through hole of the link member 3 and the through hole of the link connecting portion 2c of the back plate. It is connected with respect to the rocking motion.

  In this way, by interposing the link member 3 between the rear portion of the seat receiving member 11 and the lower portion of the back plate 2, the lower left and right end portions of the back plate 2 are independent of the seat receiving member 11 and the seat 12 and are seated. Rotate around the connecting pins 3a, 3b in the horizontal direction, that is, in the horizontal axis direction while maintaining a certain distance from the rear end portions of the receiving member 11 and the seat 12 (in other words, the lower left and right ends of the back plate 2 are connected to each other). It rotates around the connecting pin 3b while revolving around the pin 3a).

  The back frame 5 is composed of a pair of left and right left back frames 5A and 5B, and the left back frame 5A and the right back frame 5B are each a connecting plate for connecting the arms 5a and intermediate portions of the arms 5a. It consists of member 5b.

  The left back frame 5A and the right back frame 5B are configured such that the respective connecting plate members 5b and 5b overlap each other and the arms 5a and 5a are separated from each other, and the upright members 1b of the back frame support member 1 are separated. It is swingably attached to the upper end portion.

  The back frame 5 is formed of a material that can exhibit a rigidity that does not easily deform when a force assumed in normal use as a chair is applied.

  The backrest deflection adjustment mechanism of the present invention is a chair having a backrest that is supported by a pair of left and right back frames 5A and 5B and includes a back plate 2 that can be elastically deformed, and a pair of left and right back frames 5A and 5B. Thus, the back plate 2 is bent by applying a lateral force to the back plate 2 to adjust the backward bending amount of the back plate 2.

  In the present embodiment, only the back plate 2 is illustrated and described as corresponding to the backrest. However, as described above, the backrest may be configured as having a cushion material and a cover.

  In the present embodiment, the back plate 2 has a curved shape in which the left and right central portions protrude rearward (bends backward) in plan view and the back view 2 surrounds the waist of the seated person centering on the backrest point 2a. Is a shape projecting forward (projecting), and the whole is integrally formed of a flexible material. Specifically, the back plate 2 is formed of a resin such as polypropylene or nylon. However, the resin that can be the material of the back plate 2 is not limited to these, and the back plate 2 may be formed of a material other than the resin. In the present specification, a position that is generally forward most in the vicinity of the waist of the backrest surface is referred to as a backrest point.

  Further, in the present embodiment, left and right slits 2b and 2b are formed at the upper and lower positions of the backrest point 2a, which is an overhanging portion (protruding portion) projecting forward of the back plate 2, respectively. The number and shape of the slits formed in the back plate 2 are not limited to the configuration of the present embodiment, and the slits may not be formed.

  In the present embodiment, as shown in FIG. 7, the upper portion of the back plate 2 is supported on the back plate 2 so as to be rotatable about the vertical axis L, and is rotatable about the horizontal axis H. The left and right back frames 5A and 5B are supported by the left and right back frames 5A and 5B via a rotating block 6c to which the upper ends of the left and right back frames 5A and 5B are connected.

  Specifically, the upper end portions of the left back frame 5A and the right back frame 5B of the back frame 5 and the left and right end portions near the upper end of the rear surface (back surface) of the back plate 2 are connected by the connecting mechanism 6. Note that the support position of the back plate 2 by the left and right back frames 5A and 5B is not limited to the back surface of the back plate 2, and the left and right back frames 5A and 5B apply a lateral force to the back plate 2 so that the back plate 2 can be supported. Any position may be used as long as the plate 2 can be bent. Specifically, for example, the coupling mechanism 6 may be attached to both the left and right edge surfaces of the back plate 2 so as to project outward from the left and right ends of the back plate 2.

  The coupling mechanism 6 is provided on each of the left and right back frames 5A and 5B. From the gripping members 6a and 6a, the mounting member 6b, the rotating block 6c, the swinging vertical pins 6d and 6d, and the swinging horizontal shaft pins 6e and 6e. Become. That is, in this embodiment, a universal joint is used as the connecting mechanism 6 between the back plate 2 and the left and right back frames 5A and 5B. However, the connecting mechanism is not limited to the universal joint, and for example, a pivot bearing or the like A ball joint or the like may be used, or an elastic body such as a coil spring or a rubber block may be used.

  The attachment member 6b has a plate shape, and two plate-like gripping members 6a and 6a extend opposite to each other from one surface of the plate-like attachment member 6b. That is, the gripping members 6a, 6a and the attachment member 6b are formed in a U shape as viewed from the side. A through screw hole is formed in each gripping member 6a.

  The surface of the plate-like attachment member 6b opposite to the gripping member 6a side is attached, for example, by screwing to the left and right end portions near the upper end of the rear surface of the back plate 2.

  A rotating block 6c is disposed between the two gripping members 6a and 6a. Two through holes that are orthogonal to each other at the center position are formed in the rotary block 6c. In this embodiment, the rotary block 6c is formed in a cube, but the shape of the rotary block 6c is not limited to this, and may be, for example, a sphere.

  Then, the two oscillating vertical axis pins 6d, 6d pass through the through screw holes formed in the gripping member 6a from above the upper gripping member 6a and below the lower gripping member 6a, respectively, and pass through the rotary block 6c. The rotating block 6c is attached between the two gripping members 6a and 6a by being inserted into the holes. The shaft portion (pin) of the swinging vertical axis pin 6d is adjusted to a length that does not reach the portion where the two through holes formed in the rotating block 6c intersect.

  Here, no thread is formed at the tip portion of the shaft portion of the swinging vertical pins 6d, 6d, while a thread is formed at the root portion of the shaft portion. The vertical axis pins 6d and 6d are screwed and fixed to the gripping members 6a and 6a by screws at the base of the shaft portion, and support the rotary block 6c by the shaft tip end portion so that the slide shaft can rotate. .

  That is, the rotation block 6c is supported by the swinging vertical axis pins 6d and 6d so as to be rotatable about the vertical axis L with respect to the gripping members 6a and 6a. The vertical axis L is generally the vertical axis.

  The upper end portion of the arm 5a of the back frame 5 is formed in a U-shaped cross section with the opening facing the back plate 2 side, and is formed of two plates projecting from the left and right side walls facing the back plate 2 facing each other. Gripping portions 5c, 5c are formed. A through screw hole is formed in each grip portion 5c.

  Then, with the two gripping portions 5c and 5c sandwiching the rotation block 6c from the left and right, the two swinging horizontal shaft pins 6e and 6e are respectively connected to the right side of the right gripping portion 5c and the left side of the left gripping portion 5c. The upper end portion of the arm 5a of the back frame 5 is connected to the rotary block 6c through the through screw hole formed in the grip portion 5c and inserted into the through hole of the rotary block 6c. The shaft portion (pin) of the swinging horizontal shaft pin 6e is adjusted to a length that does not reach the portion where the two through holes formed in the rotating block 6c intersect. Therefore, coupled with the structure of the swinging vertical axis pin 6d described above, the swinging vertical axis pins 6d, 6d and the swinging horizontal axis pins 6e, 6e do not contact each other in the rotating block 6c.

  Here, no thread is formed at the tip portion of the shaft portion of the swinging horizontal shaft pins 6e, 6e, while a thread is formed at the root portion of the shaft portion. The horizontal shaft pins 6e and 6e are screwed and fixed to the grip portions 5c and 5c by screws at the shaft base, and support the rotary block 6c by the shaft tip end portion so that the slide block can rotate. .

  That is, the upper end portion of the arm 5a is connected to the rotary block 6c by the swinging horizontal shaft pins 6e and 6e so as to be rotatable about the horizontal shaft H. The horizontal axis H is the left-right direction axis.

  With the above-described configuration, the upper left and right ends of the back plate 2 can be rotated about the vertical axis L and can be rotated about the horizontal axis H via the rotation block 6c, and the height position is fixed. It is supported by the upper end part of the back frame 5 (arm 5a). In this way, by making the support portion of the back plate 2 supported by the back frame 5 (arm 5a) axially rotatable in each direction, the stress does not concentrate on the support portion when the back plate 2 is deformed. Can be prevented from being damaged and worn, and the back plate 2 is easily deformed smoothly, so that it is easy to use and comfortable to use.

  As described above, the upper portion of the back plate 2 is supported by the back frame 5 so that the height position is fixed by the coupling mechanism 6 and the vertical axis center and the horizontal axis center can be rotated. By connecting to the seat receiving member 11 so as to be rotatable around the horizontal axis, the degree of freedom when the back plate 2 is deformed is high, so that the necessary deformation of the back plate 2 is performed smoothly.

  A through hole 5d is formed in each of the connecting plate members 5b of the left back frame 5A and the right back frame 5B constituting the back frame 5. In the backrest deflection adjustment mechanism according to the present embodiment, the left back frame 5A and the right back frame 5B swing around the through-hole 5d to apply or release a lateral force on the back plate 2. Or

  An annular sliding support member 3 is attached to the through holes 5d of the left back frame 5A and the right back frame 5B. An annular protrusion 3 a that goes around the edge is formed on the inner edge of the sliding support member 3. Then, the sliding support member 3 is attached to the left back frame 5A by fitting the protrusion 3a into the through hole 5d from the front side and from the rear side to the right back frame 5B. The left back frame 5A and the right back frame 5B are slidable with respect to the sliding support member 3.

  On the other hand, the upright member 1b of the back frame support member 1 is provided with a plate portion 16a between a pair of left and right opposing side walls at the upper end portion, and a slide having an annular peripheral wall extending backward from the plate portion 16a. A moving support portion 16b is provided. A through screw hole 16c is formed at the center of the sliding support portion 16b.

  The left back frame 5A in which the sliding support member 3 is attached to the front side of the coupling plate member 5b is attached to the sliding support portion 16b at the upper end of the upright member 1b of the back frame support member 1. The right back frame 5B, which is attached to the through hole through the sliding support portion 16b and is further attached to the rear surface side of the coupling plate member 5b, is a through hole at the center of the sliding support member 3. The sliding support part 16b is penetrated and attached.

  At this time, the coupling plate member 5b of the left back frame 5A and the coupling plate member 5b of the right back frame 5B, which come into contact with each other as described above, are slidable.

  Further, a disc-shaped lid member 4 is provided on the rear surface of the sliding support member 3 attached to the right back frame 5B.

  A through hole 4a is formed at the center position of the lid member 4, and a screw 14 that reaches from the through hole 4a to the through screw hole 16c at the center of the sliding support portion 16b of the upright member 1b and passes therethrough is inserted from the through hole 4a. And screwed into the through screw hole 16c.

Accordingly, the left back frame 5A and the right back frame 5B are attached to the upper end portion of the upright member 1b of the back frame support member 1 so as to be swingable left and right via the sliding support portion 16b.

  Subsequently, in order to swing the left and right back frames 5A and 5B by transmitting the operation by the operation lever 17 as the operation unit in the present embodiment and applying a lateral force to the left back frame 5A and the right back frame 5B. In the present embodiment, the operation transmission mechanism includes a link mechanism 7 including an upper link 7A and a pair of left and right lower links 7B and 7B (hereinafter also referred to as right and left lower links 7B and 7B as appropriate) and a pair of left and right sliders 9 and 9. And have.

  The operation lever 17 according to the present embodiment includes a grip 17a, a first main shaft portion 17b extending from the grip 17a, and a bend from the first main shaft portion 17b. And an eccentric shaft portion 17c which is eccentric from the second main shaft portion 17d which is bent again from the eccentric shaft portion 17c and has the same axial center position as the first main shaft portion 17b.

  A through hole is provided at an intermediate position between a pair of left and right side walls that constitute the upright member 1 b of the back frame support member 1. Then, the shaft portion of the operation lever 17 is inserted into the through hole, the first main shaft portion 17b of the operation lever 17 is rotatably supported on one side wall of the upright member 1b, and the second main shaft portion 17d is supported on the other side wall. Is supported rotatably, and an eccentric shaft portion 17c is disposed between the pair of left and right side walls.

  The upper link 7A is formed in an elongated plate shape, and a through hole 7Aa is provided at the upper end portion. The upper link 7A is disposed between a pair of left and right side walls constituting the upright member 1b by passing the eccentric shaft portion 17c of the operation lever 17 through the through hole 7Aa.

  The upper link 7A includes a guide plate 7Ab fixed to a convex portion protruding forward from the front surface and a lower link mounting plate 7Ac fixed to a convex portion protruding rearward from the rear surface.

  In the present embodiment, a link support mechanism 18 that slides and holds the guide plate 7Ab of the upper link 7A is provided. As a base for attaching the link support mechanism 18, the upright member 1 b of the back frame support member 1 is an intermediate portion and includes a plate portion 18 a between a pair of left and right opposing side walls. The plate portion 18a is formed with through screw holes (six in this embodiment).

  On the rear surface of the plate portion 18a between the left and right side walls of the upright member 1b, a frame member 18b that accommodates the guide plate 7Ab is provided in a central space. A through hole is formed in the frame portion of the frame member 18b in accordance with the position of the through screw hole of the plate portion 18a provided in the upright member 1b.

  The rear surface of the frame member 18b is provided with a lid member 18c having a vertical slit (narrower than the horizontal width of the guide plate 7Ab) at the left and right center position. A through hole is also formed in the peripheral portion of the lid member 18c in accordance with the position of the through screw hole of the plate portion 18a provided in the upright member 1b.

  The plate portion 18a is provided with a frame member 18b. The guide plate 7Ab is accommodated in the inner space of the frame member 18b, and the convex portion on the front surface to which the guide plate 7Ab of the upper link 7A is fixed penetrates the slit in the vertical direction. The lid member 18c is provided, and a bolt is inserted from the through hole of the lid member 18c, passes through the through hole of the frame member 18b, and is screwed to the through screw hole of the plate portion 18a.

  The frame member 18b and the lid member 18c are fixed to the plate portion 18a in a state where the guide plate 7Ab is slidably accommodated as described above, and the frame member 18b and the lid member 18c are slidably held by the guide plate 7Ab. Guides the vertical movement of the link 7A.

  A through hole is formed at a position near both ends in the longitudinal direction of the lower link 7B. Further, both ends in the longitudinal direction of the lower link 7B are formed in an arc shape, and a gear is formed at one end.

  A pair of left and right screw holes is formed in the lower link mounting plate 7Ac of the upper link 7A. And the rocker shaft pin which has a shaft part which consists of a root part in which a screw thread is not formed, and a tip part in which a screw thread is formed is on the end side where the gear of the lower link 7B is formed. Two lower links 7B and 7B are swingably attached to the lower link mounting plate 7Ac in a state where the positions of the through holes and the through holes of the lower link mounting plate 7Ac are matched.

  A slider guide 19 is attached at a position near the lower end of the upright member 1 b of the back frame support member 1. The slider guide 19 has a bottom plate and a front wall and left and right side walls, and supports a pair of left and right sliders 9 and 9 slidably by the bottom plate and the front wall via a slider plate 19a.

  The left and right side walls of the slider guide 19 are provided with through holes, and the sliders 9 and 9 are also provided with left and right through holes. The slider guide 19 has a through hole in the left and right side walls of the slider guide 19 and the left and right pair of sliders 9, 9 in the horizontal direction with the pair of left and right sliders 9, 9 placed in the slider guide 19. A slider shaft 19b penetrating all of the holes is provided. Note that stoppers (not shown) are attached to both ends of the slider shaft 19b in a state of being provided in the slider guide 19 to prevent the slider shaft 19b from coming off.

  As a result, each slider 9 slides in the left-right direction while being supported by the slider guide 19 and the slider plate 19a and guided by the slider shaft 19b while being fixed in the vertical position.

  A screw hole is formed in the rear surface of each slider 9. Further, as described above, through holes are formed at positions near both ends in the longitudinal direction of the left and right lower links 7B, 7B. Furthermore, a through hole 5e is formed at the lower end of each of the left and right back frames 5A and 5B. In addition, the through-hole 5e is formed in the long hole which has the inclination which makes | forms a C-shape with two right and left in the installation state of right and left back frame 5A, 5B.

  Then, the left and right lower links are positioned behind the pair of left and right sliders 9 and 9 by aligning the positions of the through holes on the end side (that is, the lower end side) where no gear is formed at the positions of the screw holes on the rear surface of the slider 9. 7B and 7B are provided with lower end portions, and behind them, the lower end portions of the left and right back frames 5A and 5B are provided with the positions of the through holes 5e at the lower end portions aligned with the screw holes on the rear surface of the slider 9. In addition, the swinging shaft pin having a shaft portion including a root portion where no screw thread is formed and a tip portion where the screw thread is formed serves as a through hole of the back frames 5A and 5B and the lower link 7B. It penetrates the through hole and is inserted into the screw hole of the slider 9 and screwed.

  Thereby, the lower link 7B and the back frames 5A and 5B are slidably connected to the slider 9. Note that the left and right lower links 7B and 7B are attached in a C-shape when viewed from the rear.

  With the above-described configuration, the left and right back frames 5A and 5B swing around the through hole 5d as the slider 9 slides left and right.

  Specifically, as described above, the operation lever 17 of the present embodiment is decentered from the first main shaft portion 17b and the second main shaft portion 17d having the same shaft center position, and the shaft center positions of the main shaft portions 17b and 17d. And an eccentric shaft portion 17c. Since the upper link 7A is connected to the eccentric shaft portion 17c, the upper link 7A moves up and down by rotating the operating lever 17 about the axis.

  Since the upper ends of the left and right lower links 7B and 7B are connected to the lower end of the upper link 7A, and the slider 9 whose vertical position is fixed is connected to the lower ends of the left and right lower links 7B and 7B, When the upper link 7A moves up and down, the lower link 7B absorbs the up and down movement of the upper end by sliding the lower end in the left and right directions, and the slider 9 moves to the left and right.

  When the upper link 7A moves upward, the left and right sliders 9, 9 connected to the lower ends of the left and right lower links 7B, 7B move so as to approach each other, and the left and right back frames 5A, 5B connected to the lower ends thereof. Swings about the through hole 5d and moves so that the upper end portions are separated from each other, and a lateral force is applied to the upper portion of the back plate 2. Specifically, the upper part of the back plate 2 is expanded in the left-right direction, and the amount of backward deflection of the cross-sectional shape of the back plate 2 is reduced (FIG. 2).

  On the other hand, when the upper link 7A moves downward, the left and right sliders 9, 9 connected to the lower ends of the left and right lower links 7B, 7B move away from each other, and the left and right back frames 5A connected to the lower ends thereof. , 5B swing around the through-hole 5d and move so that the upper end portions approach each other, and a lateral force is applied to the upper portion of the back plate 2. Specifically, the upper part of the back plate 2 is narrowed in the left-right direction, and the amount of backward bending of the cross-sectional shape of the back plate 2 is increased (FIG. 3; The shape of the back plate 2 when the amount of bending is small).

  As described above, according to the backrest deflection amount adjusting mechanism of the present invention, the rearward deflection amount of the cross-sectional shape of the back plate 2 can be changed according to the preference of the seated person or adjusted according to the body shape. It is possible to improve the comfort of use by leaning on the backrest.

  In addition, although the above-mentioned form is an example of the suitable form of this invention, it is not limited to this, A various deformation | transformation implementation is possible in the range which does not deviate from the summary of this invention. For example, in the above-described embodiment, the case where the backrest deflection amount adjusting mechanism of the present invention is applied to the chair 20 whose overall structure is shown in FIG. 1 has been described as an example, but the chair to which the present invention can be applied is described above. It is not restricted to the chair 20 of embodiment. Specifically, for example, in the above-described embodiment, the present invention is applied to a single plate-like back plate 2, but the belt plate frame-like back frame constituting the peripheral portion of the backrest is used. The present invention is also applicable to this case. Moreover, in the above-described embodiment, the seat portion is configured by the seat receiving member 11 and the seat 12, but the seat portion in the present invention is not limited to the configuration of the above-described embodiment. The seat part by which the structure corresponding to the seat receiving member 11 and the seat 12 of embodiment is comprised as an integral thing may be sufficient. Further, the mechanism for supporting the seat 12 by the seat receiving member 11 is not limited to the configuration of the above-described embodiment, and for example, the elastic support member 12a and the connection support mechanism 12b may not be provided.

  In the above-described embodiment, the rotary block 6c is supported so as to be rotatable about the vertical axis L with respect to the back plate 2, and the upper end portion of the arm 5a is rotated about the horizontal axis H with respect to the rotary block 6c. Although the connection is possible, the relation of the direction of shaft rotation may be reversed. That is, the opposing direction of the two gripping members 6a, 6a on the back plate 2 side and the opposing direction of the two gripping portions 5c, 5c on the arm 5a side are rotated 90 degrees, and the rotating block 6c is relative to the back plate 2. The upper end portion of the arm 5a may be connected to the rotary block 6c so as to be rotatable about the vertical axis. In the above-described embodiment, the connecting mechanism 6 is configured to be rotatable about the vertical axis and the horizontal axis, but may be configured to be rotatable only about the vertical axis (L). Also in this case, since the degree of freedom of main shaft rotation when the backrest is bent and deformed backward in a cross-sectional shape is secured, the stress concentration in the support portion can be greatly reduced. Further, the connection for supporting the back plate 2 by the left and right back frames 5A and 5B is not a flexible connection as in the above-described embodiment using the connection mechanism 6, but a fixed connection. good. Even in this case, the back plate 2 having flexibility can be deformed.

  In the above-described embodiment, the lower portion of the back plate 2 is connected to the rear portion of the seat receiving member 11 via the link member 3, but the connection by the link member 3 is not an essential configuration of the present invention. The method of supporting the lower portion of the back plate 2 is not limited to the configuration of the above-described embodiment, and may be a structure in which the lower portion of the back plate 2 is not supported. Even if the method of supporting the lower portion of the back plate 2 is different from the configuration of the above-described embodiment, it is of course flexible in the case where the lower portion of the back plate 2 is not supported. The back plate 2 can be deformed.

  Further, the configuration of the mechanism for applying a lateral force to the back plate or the back frame by the pair of left and right back frames is not limited to that of the above-described embodiment (hereinafter referred to as the first embodiment). Specifically, for example, as shown in FIG. 9 (second embodiment; in the following description, the same components as those in the first embodiment are denoted by the same reference numerals and detailed description thereof is omitted). The left and right sliders 9, 9 may be slid in the left-right direction by the screw mechanism 22. The screw mechanism 22 as the operation unit in the present embodiment includes a grip 22a, a left and right shaft 22b extending from the grip 22a, and a left screw 22c and a right screw 22d provided on both left and right sides of the shaft 22b. And have. For example, the thread of the left-hand screw 22c is a left-handed male screw, and a left-handed female screw through-hole is formed in the slider 9 connected to the lower end of the left back frame 5A (the left-handed helix is a helical gear). In combination with the left-handed worm), the screw thread of the right-hand screw 22d is a right-handed male screw, and a right-handed female screw through hole is formed in the slider 9 connected to the lower end of the right back frame 5B (right-handed twist). A combination of helical gears and right-handed twist worms). Even in the configuration using this screw mechanism 22, the left and right sliders 9, 9 can be moved closer to and away from each other by rotating the grip 22a, thereby swinging the left and right back frames 5A, 5B. It is possible to apply a lateral force to the back plate 2 by moving it. When the screw mechanism 22 is used, the backward deflection amount of the back plate 2 can be adjusted steplessly.

  In the first and second embodiments, the slider 9 is connected to the lower end of the arm 5a of the back frame. However, the connecting position of the slider 9 and the arm 5a of the back frame is not limited to this. Absent. For example, the slider 9 and the arm 5a may be coupled at a position above the connecting plate member 5b of the back frame. Specifically, as shown in FIG. 10 (third embodiment), a screw mechanism 22 is applied as an operation unit, and the left and right sliders 9 and 9 are respectively attached to the arms 5a and 5a of the left and right back frames 5A and 5B. You may make it connect with.

  In the first to third embodiments, the left and right back frames 5A and 5B are configured to have the arm 5a and the coupling plate member 5b, and the left and right back frames 5d are formed around the through-hole 5d formed in the coupling plate member 5b. While the back frames 5A and 5B are swung, a lateral force is applied to the back plate 2. However, the configurations of the left and right back frames 5A and 5B and the configuration for swinging the back frames are not limited thereto. It is not something that can be done. For example, as shown in FIG. 11 (fourth embodiment), the left back frame 5A is formed in an L shape (may be a square shape), and the right back frame 5B is an L shape in the left-right direction (may be a square shape). The left and right sliders 9, 9 may be connected to the lower ends of the left and right back frames 5A, 5B, respectively. In the example shown in FIG. 11, the left and right sliders 9 are slid in the left-right direction by the screw mechanism 22. Also in this configuration, the left and right back frames 5A, 5B can be widened or narrowed by sliding the left and right sliders 9, 9 in the left-right direction by means of the screw mechanism 22 as the operation unit. A lateral force can be applied to the plate 2.

  Further, in the first to fourth embodiments, in order to adjust the amount of backward bending of the back plate 2, a pair of left and right back frames 5A and 5B applies a lateral force to the back plate 2. A configuration (fifth embodiment) shown in FIG. 12 may be taken as a configuration for adjusting the backward deflection amount of the back plate 2. That is, the back frame is configured to include a back frame main portion 5 ′ and a back frame left branch portion 5A ′ and a back frame right branch portion 5B ′ as a back frame extending in the left-right direction, and the back frame left branch portion 5A ′. And the back frame right branch 5B ′ support the left and right sides of the back plate 2. Further, a pressing mechanism 23 having a grip 23a and a screw shaft portion 23b is provided at the center position between the back frame left branch 5A ′ and the back frame right branch 5B ′. And you may make it adjust the press (namely, force of the front-back direction) to the left-right center position of the backplate 2 by putting in and out the screw shaft part 23b in the front-back direction by rotating the grip 23. FIG. In the case of this configuration, the back plate 2 is formed so that the amount of backward bending is maximized when the pressing by the pressing mechanism 23 is released. Also with this configuration, it is possible to adjust the amount of backward bending of the back plate 2.

  In the first to fifth embodiments, the upper portion of the back plate 2 is supported by the back frame 5, but the support position of the back plate 2 by the back frame 5 is not limited to the upper portion. The middle part of 2 may be sufficient. And even if it is made to apply the force of the left-right direction in the intermediate part of the backplate 2, the back deflection amount of the backplate 2 can be adjusted. Note that the back plate 2 is supported by the back frame 5 above the middle position between the top and bottom of the back plate 2, particularly at a position near the upper end, so that the back plate 2 is restrained at the lower end. Since it is not affected by restraint, it is easy to deform when a lateral force is applied.

DESCRIPTION OF SYMBOLS 1 Back frame support member 2 Back board 3 Link member 5 Back frame 5A Left back frame 5B Right back frame 11 Seat receiving member 12 Seat 20 Chair

Claims (5)

In a chair having a backrest that is supported by a pair of left and right back frames and has an elastically deformable back plate or back frame, the pair of left and right back frames swings to cause the back plate or back frame to move horizontally. A backrest deflection adjustment mechanism that adjusts a rearward deflection amount of the back plate or the back frame by applying force to bend the back plate or the back frame.   The back plate or the back frame is supported via a connecting mechanism provided on each of the pair of left and right back frames, and is supported by the pair of left and right back frames so that the shaft can be rotated by a vertical axis included in the connecting mechanism. The backrest deflection adjustment mechanism according to claim 1, wherein   2. The backrest deflection adjustment according to claim 1, wherein the left and right sides of the back surface of the back plate or the back frame are supported by the pair of left and right back frames above an intermediate position between the back plate and the back frame. mechanism. In a chair having a backrest that is supported by a pair of left and right back frames and has an elastically deformable back plate or back frame, the left and right back frames move in the left-right direction by operating an operation unit. backrest deflection amount you and adjusting the deflection amount to the rear of the back plate or the back frame by flexing the back plate or the back frame by adding the lateral direction of the force to the back plate or the back frame Adjustment mechanism. In a chair having a backrest supported by a back frame extending in the left-right direction and having an elastically deformable back plate or back frame, the back plate or the back frame has left and right connecting mechanisms provided on the back frame. The left and right sides of the back of the back plate or back frame are supported so as to be axially rotatable above the back plate or back frame intermediate position by the vertical axis provided, and at the same vertical position as the left and right connecting mechanism by the a provided pressing mechanism to the back frame by adding longitudinal force to the right and left middle portion of the back plate or the back frame deflect the back plate or the back frame, deflection to the rear of the back plate or the back frame A back deflection adjustment mechanism characterized by adjusting the amount.

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