JP2012135454A - Chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chair with high durability even in a simple configuration.SOLUTION: The chair includes an elastic frame 8 which can be bent and deformed and is constituted so that a tip end 82 can receive a load applied to a back rest 6 when the back rest 6 is backwardly tilted, on which the tip end 82 and the base end 81 are rotatably mounted. The elastic frame 8 changes so that the distance between the base end 81 and the tip end 82 gets closer as the back rest 6 is backwardly tilted, obtaining elastic deformation with larger curvature. Therefore, an appropriate resilient repulsive force can be given to the back rest 6.

Description

  The present invention relates to an office swivel chair preferably used in an office or the like.

  Conventionally, various chairs have been proposed that can impart an appropriate elastic repulsion force to the backrest by deformation of a member that can be elastically deformed (see, for example, Patent Document 1). This is because the upper frame of the backrest and the lower frame are provided with a resin spring made of an elastically deformable resin with the distal end portion and the base end portion fixed, and the upper portion of the backrest is tilted backward. Along with this, the resin spring is elastically deformed, so that it is possible to apply an appropriate backward tilting force that can suitably follow the movement of the upper body of the seated person.

  However, since both ends of the member that is elastically deformed are fixed in the above-described Patent Document 1, a portion where the force applied to the member during elastic deformation is large and a portion where the force is small are unevenly distributed. . And in view of continuous use, such chairs have been precisely determined in terms of the specific shape and material of the resin spring, taking into account the strength of the force applied to each part, especially during elastic deformation. . That is, the chair according to Patent Document 1 requires labor for precisely determining the specifications of the resin spring.

JP 2007-130345 A

  The present invention pays attention to such a problem, and an object thereof is to provide a chair that can obtain high durability even with a simple configuration by elastically deforming parts while applying a load evenly. .

  In order to achieve such an object, the present invention takes the following measures.

  That is, the chair according to the present invention is a chair configured such that the backrest can be tilted backward, the tip portion being configured to receive a load applied to the backrest when the backrest is tilted backward, and the tip portion and It comprises an elastic frame that can be bent, at least one of which is rotatably attached to the base end portion, and this elastic frame is located between the base end portion and the tip end portion as the backrest tilts backward. It is characterized in that an elastic repulsive force is applied to the backrest by elastic deformation in which the curvature changes as the distance changes.

  Here, the configuration that can receive the load applied to the backrest when tilting after the backrest is not limited to the mode in which the elastic frame is directly attached to the backrest, but indirectly, for example, by being attached to the backrest. It is also a concept including a configuration that receives a load applied to the.

  If this is the case, the elastic frame has a base end portion or a distal end portion that is rotatably attached, and the elastic frame does not concentrate on the place where it is rotatably attached, and the force at the time of tilting back is concentrated. The whole can be uniformly deformed. Accordingly, it is possible to contribute to the realization of a highly durable chair by effectively avoiding local fatigue of the elastic frame even by continuous use.

  In addition, in order for the elastic frame not to interfere with other components of the chair and to form the chair compactly, the elastic frame should have a curved shape along the back side of the backrest and under the seat. Is desirable.

And in the present invention, depending on the specific shape of the chair and the mounting position of the elastic frame,
A configuration in which the elastic frame is elastically deformed so that the distance between the base end portion and the tip end portion is close when the backrest is tilted backward, and a configuration in which the distance between the base end portion and the tip end portion is spaced apart Also, as described above, excellent durability can be realized.

  In order to realize the present invention with a simple configuration using the configuration of the back support rod that is configured to be rotatable, the backrest is elastically deformed by being pivotally attached to the support base supported by the legs. It is assumed that the elastic frame is rotatably supported by a back support rod having a structure that cannot be obtained, and the elastic frame may be pivotally attached at a position different from the rotation center of the back support rod in the support base. .

  In order for the elastic frame to exert an appropriate elastic repulsive force while effectively avoiding an excessive increase in the load applied to the elastic frame, the back support rod and the link element that supports the seat It is desirable to apply a so-called weight-sensing configuration in which the link elements are moved in the direction of raising the seat by the rotational movement of the back support rod accompanying the back tilt of the backrest.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a simple structure, the chair which can acquire high durability can be provided.

The perspective view of the chair which concerns on 1st embodiment of this invention. The other perspective view. The same side view. Action explanatory drawing corresponding to FIG. The perspective view of the chair which concerns on 2nd embodiment of this invention. The same side view. Action explanatory drawing corresponding to FIG. The perspective view of the chair which concerns on 3rd embodiment of this invention. The same side view. FIG. The perspective view of the chair which concerns on 4th embodiment of this invention. Action explanatory drawing corresponding to FIG.

  Hereinafter, each embodiment of the present invention will be described with reference to the drawings.

  In these embodiments, the present invention is applied to an office swivel chair.

<First embodiment>
As shown in FIGS. 1 to 4, the chair according to the first embodiment of the present invention includes a leg 1, a support base 2 supported by the leg 1, and a seat 3 disposed on the support base 2. A seat 4 supported by the seat support 3, a back support rod 5 rotatably supported by the support base 2, a backrest 6 attached to the back support rod 5, and a backrest 6 It comprises a locking mechanism 7 for moving the seat receiver 3 and the seat 4 upward in accordance with a backward tilting operation, and an elastic frame 8 for applying a reaction force when the backrest 6 is tilted backward.

  As shown in FIGS. 1 to 4, the leg 1 includes a leg base 11 and leg struts 12 provided at the center of the leg base 11. As shown in the figure, the leg base 11 is provided with a plurality of leg blades 13 projecting radially from a hub provided at the center, and a caster 14 is provided at the tip of the leg blade 13. The leg support 12 is of a gas spring type and is a normal one that elastically expands and contracts in the vertical direction and can be locked at a desired position. That is, the leg strut 12 has a rod 16 projecting from the upper end of the main body portion of the gas spring fitted to the hub of the leg base 11, and an unlocking operation button 17 is provided at the upper end of the rod 16. Is protruding. The support base 2 is mounted on the upper end of the rod 16. The unlocking operation button 17 is operated by a lifting operation lever 15.

  The support base 2 includes a main frame 21 attached to the rod 16 of the leg column 12, a front link shaft attaching portion 22 and a rear link shaft attaching portion 23 attached to the main frame 21, and a frame for attaching the elastic frame 8. The shaft attachment portion 24 is provided. In FIG. 1 and FIG. 2, illustration of an intermediate portion attached to the leg support 12 in the main frame 21 is omitted, and only the outer shape is shown by a broken line. The front link pivot 22 is for supporting the front end of the seat 3 via the front link 71. The rear link shaft attaching portion 23 supports the back support rod 5 including the back support arm 51 so as to be rotatable at a position in front of the leg support 12 and is also a seat receiving portion that is an intermediate portion of the seat 4 through the rear link 72. 3 for supporting a substantially intermediate portion. The frame pivoting portion 24 is positioned at the rear end portion of the main frame 21 on the rear side of the leg support 12, and supports the base end portion 81 of the elastic frame 8 so as to be rotatable.

  The seat base 3 is supported on the support base 2 configured as described above via the front link 71 and the rear link 72. In this embodiment, the seat receiver 3 is integrally formed by bending a metal plate, for example. On the lower surface of the seat 3, a front link mounting portion 31 for mounting the front link 71 at a position from the front end portion, and a rear link mounting portion for mounting a rear link 72 provided at a substantially central position in the front-rear direction. 32 is provided. The front link attachment portion 31 and the rear link attachment portion 32 are provided integrally with the seat receiver 3.

  The seat 4 is a normal one provided with an inner shell attached to the upper surface of the seat receiver 3, a cushion disposed on the inner shell, and a tension fabric stretched on the outer surface of the cushion.

  The back support rod 5 includes left and right back support arms 51 that extend rearward and upward from the support base 2, an upper connection portion 52 that connects between the upper ends of the left and right back support arms 51, and the upper connection portion 52. A back support portion 53 that supports the upper portion of the backrest 6 at a slightly lower position, an intermediate connection portion 54 that connects intermediate positions of the left and right back support arms 51, and a position below the intermediate connection portion 54. It has a frame mounting portion 55 for rotatably mounting the distal end portion 82 of the elastic frame 8, and a lower back support portion 56 for supporting the lower portion of the backrest 6.

  The left and right back support arms 51 are each made of, for example, a hard resin or metal that is supported by the support base 2 so as to be rotatable and cannot be elastically deformed, and extends in the front-rear direction and extends in the front-rear direction. A portion 57 and an upright portion 58 extending continuously upward from the rear end of the front-rear direction extending portion 57 are provided. In the example of illustration, the front-back direction extension part 57 and the standing part 58 have comprised the substantially U shape in the side view. Each back support arm 51 is integrally connected to the upper end of the rear link 72 that is a link element at the base end thereof, that is, the front end portion of the longitudinally extending portion 57.

  The backrest 6 is supported on the dorsal support 5 formed as described above. The backrest 6 is a normal one including a resin back shell 61 and a tension fabric 62 attached to the surface side of the back shell 61.

  The backrest 6 configured as described above and the seat 4 are interlocked by a locking mechanism 7. The locking mechanism 7 is of a weight sensing type in which the seat 4 is moved upward while being tilted in accordance with the backward tilting motion of the backrest 6. More specifically, as shown in FIGS. 3 to 4, the locking mechanism 7 includes a support base 23, a front link 71 having a lower end rotatably supported by the support base 2, and an upper end of a back support arm. The rear link 72 and the front link mounting part 31 are connected to the front link 71 and the rear link mounting part 32 are made to be integrated with the rear link arm 51 so that the center of rotation is equal to the rotation center of the back support arm 51. The seat 3 that is connected to the rear link 72 is mainly configured.

  That is, the locking mechanism 7 is supported by the support base 2 by the support base 2 supported by the front link 71 and the rear link 72 that are inclined in the forward direction, which is the same direction, to support the seat 4. In accordance with the backward tilting operation of the back support arm 51, the front link 71 and the rear link 72 are rotated in the standing direction to lift the seat 4 and the seat receiver 3 upward. When the backrest 6 is tilted backward, the front part of the seat 4 is lifted more than the rear part. In other words, in the normal backrest 6 and the synchro-rocking mechanism of the seat 4, the seat 4 is tilted only in the downward direction in accordance with the backward tilting operation of the backrest 6, but weight sensing as shown in the present embodiment is possible. Unlike the normal locking mechanism, the rocking mechanism 7 of the type is configured to lift the seat 4 against the load of the seated person while tilting the seat 4 in accordance with the backward tilting operation of the backrest 6. .

  Specifically, as shown in FIG. 3, when the backrest 6 is not tilted backward, the forward link 71 is set so that the forward tilt degree of the front link 71 is larger than the forward tilt degree of the rear link 72. Has been. Further, the center of rotation of the front link 71 relative to the support base 2 is set at a position higher than the center of rotation of the rear link 72 relative to the support base 2. Further, the back support arm 51 is pivotally supported by a portion of the support base 2 that is in front of the leg column 12. In addition, the point which made the forward inclination degree of the front link 71 larger than the forward inclination degree of the rear link 72 aims at raising the front side of the seat 4 relatively larger than the rear side at the time of the rear inclination. . In this embodiment, since the rear link 72 is connected to the substantially central portion in the front-rear direction of the seat receiver 3, both the front and rear links 71, 72 when the backrest 6 is tilted are configured to lift the seat receiver 3. However, since the front link 71 lifts the seat receiver 3 more than the rear link 72, the rear end portion of the seat receiver 3 can be set relatively lower than the front end portion, and the front end portion of the seat receiver 3 is raised. Further, the height position of the rear end portion of the seat 3 is hardly changed between when the backrest 6 stands and when it tilts backward.

  Thus, the chair according to the present embodiment is configured so that the distal end portion 82 can receive a load applied to the backrest 6 when the backrest 6 is tilted backward, and the distal end portion 82 and the base end portion 81 are rotatably attached. The elastic frame 8 that can be bent and deformed is provided.

  The elastic frame 8 is formed, for example, by integral molding of an elastically deformable resin. The base end portion 81 is pivotally attached to the frame shaft attachment portion 24 of the support base portion 2, and the distal end portion 82 is the back support rod 5. By being pivotally attached to the frame mounting portion 55, the load applied when the backrest 6 is tilted backward can be received via the frame mounting portion 55. In the present embodiment, the rear end portion 81 is different from the rear link shaft attachment portion 23 in which the base end portion 81 is the center of rotation of the back support rod 5 in the support base portion 2. It is pivotally attached at the rear end.

  As the backrest 6 is tilted backward, the distance between the base end portion 81 and the distal end portion 82 changes so that the distance between the base end portion 81 and the distal end portion 82 becomes closer, so that the backrest 6 It provides an elastic repulsion force.

  That is, as described above, when the link element moves in the direction of raising the seat 4 via the seat receiver 3 due to the rotational movement of the back support rod 5 accompanying the back tilt of the backrest 6, the curvature of the elastic frame 8 is As the distance increases, the distance between the proximal end portion 81 and the distal end portion 82 approaches the distance L2 shown in FIG. 4 from the distance L1 shown in FIG. As a result, the elastic frame 8 accumulates an elastic repulsion force in a direction that increases the distance between the base end portion 81 and the tip end portion 82. This elastic unidirectional force becomes a backward tilting force of the backrest 6 that works to move the backrest 6 in the upright direction.

  By setting it as the above structures, since the chair which concerns on this embodiment has the elastic frame 8 attached so that the base end part 81 or the front-end | tip part 82 can rotate, the backrest 6 inclines back to the attachment location. The entire elastic frame 8 can be uniformly deformed without concentration of time. Thereby, it can contribute to realization of a highly durable chair by effectively avoiding local fatigue of the elastic frame 8 even by continuous use.

  In the present embodiment, the elastic frame 8 is arranged along the rear side of the backrest 6 and the lower side of the seat 4 so that the elastic frame 8 does not interfere with other components of the chair and the chair is compactly configured. It has a curved shape.

  In this embodiment, the elastic frame 8 is configured to be elastically deformed so that the curvature is increased so that the distance between the proximal end portion 81 and the distal end portion 82 is close when the backrest 6 is tilted backward. Thus, it is possible to effectively avoid the elastic frame 8 from interfering with the operation of the seat 4 when the backrest 6 is tilted backward.

  Further, in the present embodiment, by positioning the rotation center of the base end portion 81 of the elastic frame 8 on the rear side of the rotation center of the back support rod 5, an aspect in which the elastic frame 8 can be elastically deformed with a simple configuration is realized. ing.

  In particular, in the present embodiment, by applying a weight sensing type configuration in which the rear link 72 as the link element moves in the direction of raising the seat 4 by the rotational movement of the back support rod 5 accompanying the back tilt of the backrest 6. The load applied to the back support rod 5 is also converted into the acting force for raising the seat 4, so that the load applied to the elastic frame 8 is effectively prevented from being excessively increased, while the elastic frame 8 is moderate. The elastic repulsive force can be exhibited.

<Second embodiment>
In the following, a second embodiment of the present invention will be described. Components that correspond to the components of the above-described embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

  The chair according to the present embodiment has substantially the same configuration as that of the first embodiment with respect to the configuration of the leg 1, the seat receiver 3, the seat 4, the backrest 6, the locking mechanism 7, and the elastic frame 8. It is a sensitive chair. Further, in this embodiment, the support base 2 is the same as the above embodiment in that it has a main frame 21, a front link pivot portion 22, a rear link pivot portion 23, and a frame pivot portion 24. Further, a front link control unit 25 for limiting the rotation range of the front link 71 is provided.

  Thus, in the present embodiment, the configuration of the back support rod 5, i.e., the extension frame portion 83 is provided on the back support rod 5, so that the extension frame portion 83 and the proximal end are in accordance with the backward inclination of the backrest 6. By elastically deforming so as to extend the distance from the portion 81, a back tilting reaction force can be generated together with the elastic frame 8.

  That is, in the present embodiment, the left and right back support arms 51 are each made of, for example, a resin that is rotatably supported by the support base 2, and below the upright portion 58 positioned along the backrest 6, An elongated frame portion 83 having a curved shape is provided. The extension frame portion 83 also corresponds to the elastic frame according to the present invention. The extension frame 83 can be deformed so that the curvature is reduced when the backrest 6 is tilted backward by appropriately adjusting the shape of the material constituting the left and right back support arms 51. Further, in the present embodiment, each back support arm 51 is differently connected to the lower end instead of the upper end of the rear link 72 which is a link element, at the base end side thereof, that is, the front end portion of the extension frame portion 83. The rear link 72 and the rear link shaft mounting portion 23 are pivotally attached to the rear link 72. Further, the upper end portion of the extension frame portion 83 is configured to be pivotally attached to the intermediate connection portion 54.

  That is, when the link element moves in the direction of raising the seat 4 via the seat receiver 3 by the rotational movement of the back support rod 5 accompanying the back tilt of the backrest 6 as described above, the elastic frame 8 is used in this embodiment. The operation of increasing the curvature of the image and the operation of decreasing the curvature of the extension frame portion 83 occur simultaneously. Thereby, the distance between the base end portion 81 and the tip end portion 82 of the elastic frame 8 approaches from the distance M1 shown in FIG. 5 to the distance M2 shown in FIG. A distance between a certain rear link shaft attachment portion 23 and the intermediate connection portion 54 is separated from N1 to N2. As a result, the elastic frame 8 and the extension frame portion 83 each store an elastic repulsive force. These elastic unidirectional forces serve as a backward tilting force of the backrest 6 that works to move the backrest 6 in the upright direction.

  As described above, the chair according to the present embodiment includes the elastic frame 8 and the extension frame portion 83 that can be elastically deformed with different curvatures. It has a simple structure and is excellent in durability.

<Third embodiment>
Subsequently, a chair according to a third embodiment of the present invention will be described with reference to FIGS. Also in the present embodiment, the same reference numerals are given to components corresponding to the components of the above embodiment.

  As shown in FIGS. 8 to 10, the chair according to the third embodiment of the present invention includes a leg 1, a support base 2 supported by the leg 1, and a seat 3 disposed on the support base 2. A seat 4 supported by the seat support 3, a back support rod 5 rotatably supported by the support base 2, a backrest 6 attached to the back support rod 5, and a backrest 6 It comprises a locking mechanism 7 for moving the seat receiver 3 and the seat 4 upward in accordance with a backward tilting operation, and an elastic frame 8 for applying a reaction force when the backrest 6 is tilted backward.

  The leg 1 includes a leg base 11 and a leg support 12 provided at the center of the leg base 11. As shown in the figure, the leg base 11 is provided with a plurality of leg blades 13 projecting radially from a hub provided at the center, and a caster 14 is provided at the tip of the leg blade 13. The leg support 12 is of a gas spring type as in the above embodiment, and is a normal one that elastically expands and contracts in the vertical direction and can be locked at a desired position. That is, the leg support 12 does not show the operation button 17 and the operation lever 15 shown in the above embodiment, but the operation button 17 for unlocking projects from the upper end of the rod 16 as in the above embodiment. The operation button 17 is operated by the operation lever 15 for raising and lowering.

  The support base 2 includes a main frame 21 attached to the rod 16 of the leg column 12, a front link shaft attaching portion 22 and a rear link shaft attaching portion 23 attached to the main frame 21, and a frame for attaching the elastic frame 8. The shaft attachment portion 24 is provided. In FIG. 8, different from the above embodiment, an intermediate portion attached to the leg support 12 in the main frame 21 is illustrated. The front link pivot 22 is for supporting the front end of the seat 3 via the front link 71. The rear link shaft attaching portion 23 supports the back support rod 5 including the back support arm 51 so as to be rotatable at a position in front of the leg support 12 and is also a seat receiving portion that is an intermediate portion of the seat 4 through the rear link 72. 3 for supporting a substantially intermediate portion. The frame pivoting portion 24 is positioned at the rear end portion of the main frame 21 on the rear side of the leg support 12, and supports the base end portion 81 of the elastic frame 8 so as to be rotatable.

  In this embodiment, the seat receiver 3 is integrally formed by bending a metal plate, for example. On the lower surface of the seat 3, a front link mounting portion 31 for mounting the front link 71 at a position from the front end portion, and a rear link mounting portion for mounting a rear link 72 provided at a substantially central position in the front-rear direction. 32 is provided. The front link attachment portion 31 and the rear link attachment portion 32 are provided integrally with the seat receiver 3.

  In the present embodiment, the seat 4 is a plate attached to the upper surface of the seat receiver 3, but of course, the seat 4 is not limited to the illustrated example, and as in the above embodiment, the inner shell and the inner shell are placed on the inner shell. It is good also as what was provided with the arrange | positioned cushion and the tension | tensile_strength stretched around the outer surface of this cushion.

  The back support rod 5 includes left and right back support arms 51 linearly extending rearward and upward from the support base 2, a back support portion 53 that supports the back support 6 so as to be sandwiched from both sides, and the back support. A frame attachment portion 55 to which the distal end portion 82 of the elastic frame 8 is fixed is provided outside the portion 53.

  The left and right back support arms 51 are made of, for example, hard resin or metal that is rotatably supported by the support base 2 and is set so as not to be elastically deformed. The upright portion 58 extending in a shape is mainly used. Each back support arm 51 is integrally connected to the upper end of the rear link 72 as a link element at the base end, that is, the lower end.

  The backrest 6 is supported on the dorsal support 5 formed as described above. In the present embodiment, the backrest 6 includes, for example, a back frame 63 fixed so as to be interposed between the back support arms 51 and a back plate 64 attached to the surface of the frame. Of course, it may have the back shell 61 and the upholstery 62 as in the above embodiment.

  The backrest 6 and the seat 4 configured as described above are interlocked by a locking mechanism 7 similar to the above embodiment. That is, the locking mechanism 7 is also of a weight sensing type in which the seat 4 is moved upward while being tilted in accordance with the backward tilting motion of the backrest 6. Specifically, as shown in FIGS. 3 to 4, the locking mechanism 7 includes a support base 23, a front link 71 having a lower end rotatably supported by the support base 2, and a lower end supported by a back support arm 51. By integrating the rear link 72 and the front link mounting portion 31 connected to the front link 71, the rear link 72 having the rotation center equal to the rotation center of the back support arm 51 in side view, and the rear link mounting portion 32 are connected to the rear link. The main body is composed of a seat 3 connected to 72.

  Therefore, the chair according to the present embodiment is fixed to the back support rod 5 and the base end portion 81 is rotatably attached so that the distal end portion 82 can receive a load applied to the backrest 6 when the backrest 6 is tilted backward. The elastic frame 8 that can be bent and deformed is provided.

  The elastic frame 8 is formed, for example, by integral molding of an elastically deformable resin. The base end portion 81 is pivotally attached to the frame shaft attachment portion 24 of the support base portion 2, and the distal end portion 82 is the back support rod 5. By being fixed to the frame mounting portion 55, the load applied when the backrest 6 is tilted backward can be received via the frame mounting portion 55. In this embodiment, unlike the rear link shaft attachment portion 23 in which the base end portion 81 is the rotation center of the back support rod 5 in the support base portion 2, the front link shaft attachment is on the front side of the rear link shaft attachment portion 23. The part 22 is pivotally attached together with the front link 71.

  As the backrest 6 is tilted backward, the elastic frame 8 is elastically deformed so that the curvature decreases as the distance between the base end portion 81 and the distal end portion 82 increases, thereby reducing the back. An elastic repulsive force is imparted to the drooping 6.

  That is, as described above, when the link element moves in the direction of raising the seat 4 via the seat receiver 3 due to the rotational movement of the back support rod 5 accompanying the back tilt of the backrest 6, the curvature of the elastic frame 8 is By becoming smaller, the distance between the base end part 81 and the front end part 82 is separated from the distance P1 shown in FIG. 9 to the distance P2 shown in FIG. As a result, the elastic frame 8 accumulates an elastic repulsive force in a direction that reduces the distance between the base end portion 81 and the tip end portion 82. This elastic unidirectional force becomes a backward tilting force of the backrest 6 that works to move the backrest 6 in the upright direction.

  As described above, like the chair according to the present embodiment, the upper end of the elastic frame 8 is fixed, and the curvature of the elastic frame 8 is reduced when the backrest 6 is tilted backward, and the proximal end 81 and the distal end are reduced. Even if it is configured such that the distance from the portion 82 is separated, the same effects as those in the above embodiments can be obtained.

<Fourth embodiment>
Subsequently, a chair according to a third embodiment of the present invention will be described with reference to FIGS. Also in the present embodiment, the same reference numerals are given to components corresponding to the components of the above embodiment.

  The chair according to the present embodiment has the same structure as the third embodiment with respect to the configuration of the leg 1, the support base 2, the seat receiver 3, the seat 4, the backrest 6, and the locking mechanism 7. It is a ceremony chair. In the present embodiment, the support base 2 is provided with the front link control unit 25 for limiting the rotation range of the front link 71 as in the second embodiment.

  Therefore, in the present embodiment, the configurations of the back support rod 5 and the elastic frame 8 are different from those of the third embodiment. That is, in this embodiment, the elastic frame 8 is provided integrally with the upper end of the back support rod 5, and the base end portion 81 is pivotally attached to the support base 2 side while the elastic frame 8 is curved in front of the back support rod 5. In this way, the elastic frame 8 is elastically deformed to extend the distance between the distal end portion 82 and the base end portion 81 in accordance with the backward inclination of the backrest 6, so that the backrest 6 and the elastic frame 8 are A backward tilting force can be generated. Specifically, the elastic frame 8 having a curved shape on the front side of the back support rod 5 is different from the rear link shaft attachment portion 23 in which the base end portion 81 is the rotation center of the back support rod 5 in the support base portion 2. The front link 71 and the front link 71 are pivotally attached to the front link pivot 22 on the front side of the rear link pivot 23. The elastic frame according to the present embodiment can be effectively used as an armrest as well as simply applying a backward reaction force to the backrest 6. Of course, the structure of the elastic frame 8 is not limited to that shown in the figure, but can be variously provided for use as an armrest, such as one provided integrally in the middle portion of the back support rod 5 or one provided with an armrest integrally or separately. Embodiments are possible.

  Also in the present embodiment, as the backrest 6 is tilted backward, the elastic frame 8 undergoes elastic deformation in which the curvature is reduced by changing the distance between the base end portion 81 and the distal end portion 82 to be separated. By doing so, an elastic repulsive force is imparted to the backrest 6.

  That is, as described above, when the link element moves in the direction of raising the seat 4 via the seat receiver 3 due to the rotational movement of the back support rod 5 accompanying the back tilt of the backrest 6, the curvature of the elastic frame 8 is By decreasing, the distance between the base end part 81 and the front end part 82 is separated from the distance Q1 shown in FIG. 9 to the distance Q2 shown in FIG. As a result, the elastic frame 8 accumulates an elastic repulsive force in the direction of decreasing the distance between the base end portion 81 and the distal end portion 82, in other words, an elastic repulsive force in the direction of increasing the curvature of the elastic frame 8. This elastic unidirectional force becomes a backward tilting force of the backrest 6 that works to move the backrest 6 in the upright direction.

  As described above, the upper end of the elastic frame 8 is fixed to the back support rod 5 as in the chair according to the present embodiment, and the curvature of the elastic frame 8 is reduced when the backrest 6 is tilted backward. Even if it is configured such that the distance between the end portion 81 and the front end portion 82 is separated, the same effects as those in the above embodiments can be obtained. In addition, according to the configuration, the elastic frame 8 can be effectively used as an armrest.

  In particular, in the present embodiment, a configuration is adopted in which the elastic frame 8 is pulled in a direction to reduce the curvature of the elastic frame 8 when the backrest 6 is tilted backward. As described above, when the elastic frame 8 is curved in advance, the elastic frame 8 is elastically deformed in the extending direction, and the linear deformation, that is, the curvature becomes zero no matter how much the deformation is performed, The deformation range of the elastic frame 8 is naturally from the initial curved state to the linear state. In other words, with this configuration, the elastic frame 8 not only gives the back tilting reaction force of the backrest 6 but also contributes to the setting of the operating range of the backrest 6 and effectively avoids the provision of a special stopper. Yes. In addition, since the state where the most force is applied to tilt the backrest 6 backward is the state where the elastic frame 8 is pulled in a straight line, an unreasonable force that would break in this state is applied to the elastic frame 8. Therefore, the durability of the elastic frame 8 is effectively improved.

  Although the embodiments of the present invention have been described above, the specific configuration of each unit is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the aspect in which the present invention is applied to a body weight sensing type chair is disclosed, but of course, the present invention is applied to a chair having a back seat synchro-rocking mechanism to which the body weight sensing type is not applied. Also good. Further, specific modes such as the specific shape and mounting position of the elastic frame are not limited to those of the above-described embodiment, and various modes including existing ones can be applied.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  The present invention can be used as an office swivel chair suitably used in an office or the like.

DESCRIPTION OF SYMBOLS 1 ... Leg 2 ... Support base 4 ... Seat 5 ... Back support 6 ... Backrest 72 ... Link element (rear link)
DESCRIPTION OF SYMBOLS 8 ... Elastic frame 82 ... Tip part 81 ... Base end part 83 ... Elastic frame (elongation frame part 83)

Claims (6)

A chair with a backrest that can be tilted backwards;
A structure in which the distal end portion is configured to receive a load applied to the backrest when tilting after the backrest and at least one of the distal end portion and the base end portion is provided with a curved elastic frame that is rotatably attached. And
The elastic frame undergoes elastic deformation in which the curvature changes as the distance between the base end portion and the tip end portion changes as the backrest tilts backward, thereby providing an elastic repulsive force to the backrest. A chair characterized by giving. The chair according to claim 1, wherein the elastic frame has a curved shape along a back side of the backrest and a lower side of the seat. The chair according to claim 1, 2, or 3, wherein the elastic frame is elastically deformed so that a distance between a base end portion and a tip end portion is close when the backrest is tilted backward. The chair according to claim 1, 2, or 3, wherein the elastic frame is elastically deformed so that a distance between a base end portion and a tip end portion is separated when the backrest is tilted backward. The backrest is rotatably supported by a back support rod that has a structure that cannot be elastically deformed and is pivotally attached to a support base supported by a leg.
The chair according to claim 1 or 2, wherein the elastic frame is pivotally attached to a base end portion at a place different from a rotation center of the back support rod in the support base portion. The back support rod is formed integrally with a link element supporting the seat;
The chair according to claim 5, wherein the link element moves in a direction in which the seat is lifted by a rotational movement of a back support rod accompanying the back tilt of the backrest.

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