JP2013132401A - Chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chair which has no need of providing on the outside a stopper or the like for suppressing too much deformation when a large load acts, is provided with appropriate elastic deformation and is capable of improving a sitting comfort.SOLUTION: A chair has a structural material 14 elastically deformed when receiving a load, a pair of opposed surfaces 113 and 133 opened on the front end side are provided integrally on an elastically deformed part of the structural material 14, and when the structural material 14 is elastically deformed, the front end sides of the opposed surfaces 113 and 133 are brought closer and the elastic deformation characteristic of the structural material is changed.

Description

  The present invention relates to a chair comprising a structural material that is elastically deformed when a load is applied.

  For various purposes such as improving sitting comfort, the material and cross-sectional shape of the synthetic resin seat frame and back frame are devised, and the seat frame and back frame are appropriately elastically deformed when a load is applied. Various devices have been developed (see, for example, Patent Document 1).

  However, in this type of chair, if the seat frame and the back frame are designed to be easily elastically deformed in order to soften the seating comfort, it may be deformed excessively when a large load is applied. It is necessary to provide a stopper or the like for keeping the elastic deformation of the seat frame and the back frame within a certain range. When a stopper or the like is provided outside, there may be a problem that the cost increases due to an increase in the number of parts, an increase in the attaching process of these parts, or the like. In addition, when the stopper or the like is exposed to the outside, the appearance as a chair is affected, and the design may be deteriorated. On the other hand, when a stopper or the like cannot be provided outside, the seat frame and the back frame must be set firmly so that excessive deformation does not occur, and the seating comfort cannot be improved. is there.

  Such a dilemma exists not only for a seat frame and a back frame, but also for various components constituting the chair.

Japanese Patent Application No. 2011-136263

  An object of the present invention is to provide a chair that can eliminate the dilemma described above.

  The present invention employs the following configuration in order to solve the above-described problems. That is, the chair according to the present invention includes a structural material that is elastically deformed by receiving a load, and is provided with a pair of opposing surfaces whose front ends are open at the elastically deformed portion of the structural material, and the structural material is elastic. The structure is characterized in that the elastic deformation characteristics of the structural material change when the tip end side of the facing surface approaches when deformed.

  Here, the “front end of the facing surface” means the end of the facing surface that is more displaced than the base end of the facing surface that is less likely to be displaced when the structural material is elastically deformed. The “front end side of” means the entire portion of the facing surface closer to the front end than the base end.

  In addition, the “proximity” includes a case of direct contact and a case of approaching gradually while compressing and deforming the elastic material between the opposing surfaces.

  If this is the case, the resilience characteristics can be changed before and after the opposing surfaces of the structural material come close to each other, so a stopper or the like for suppressing excessive deformation when a large load is applied is provided outside. There is no need to provide it, and it is possible to improve the sitting comfort by giving an appropriate elastic deformation.

  As a preferable aspect of the structural material, a hard part that elastically deforms when a load is applied is provided, and a pair that approaches the inside along with the elastic deformation as viewed from the bending direction of the hard part is formed. An opposing surface formed or provided with a hard part that is elastically deformed when a load is applied, and forms a pair that approaches the outer side with the elastic deformation as viewed from the bending direction of the hard part. One having a surface formed. Here, “inner side as viewed from the bending direction” means a side on which internal stress in the compression direction increases as a load is applied and bending deformation proceeds regardless of the shape. In other words, for example, when an arc-shaped structural material is bent and deformed in a direction in which the radius of curvature becomes smaller, the center of curvature is the inside. On the other hand, when the arc-shaped structural material is bent and deformed in the direction in which the radius of curvature increases, the side opposite to the center of curvature is the inside. Further, “outside as viewed from the bending direction” means a side on which an internal stress in the tensile direction increases as a load is applied and bending deformation proceeds regardless of the shape. In other words, for example, when an arc-shaped structural material is bent and deformed in a direction in which the radius of curvature decreases, the side opposite to the center of curvature is the outside. On the other hand, when the arc-shaped structural material is bent and deformed in a direction in which the radius of curvature increases, the center of curvature is the outside.

  As a specific aspect of the structural material, for example, a cantilevered structural material such as a back frame, a seat frame, a back frame, a seat frame, a back support rod, a headrest arm, etc. It can be considered that the opposite side is inside the elastic deformation.

  Further, as another specific aspect of the structural material, for example, a structural material that supports both ends, for example, a back plate supported on both ends, a seat plate, a lumbar support, an armrest, etc. What is inside can be considered.

  In order to realize the problem with a simple structure, it is preferable that the structural material is such that the facing surfaces directly contact each other when the structural material is elastically deformed more than a certain amount.

  The structural material includes a recessed portion that forms the facing surface, and may be one in which an elastomer is disposed on all or a portion of the recessed portion.

  The hard part is provided with a thin part and a thick part having a thickness dimension larger than that of the thin part provided on both sides of the thin part, and a recessed part is formed between the thick parts. A preferred embodiment is one in which the facing surface is formed inside the recessed portion.

  Since this invention is the above structures, the chair which can eliminate the dilemma mentioned above can be provided.

The perspective view of the chair of a 1st embodiment of the present invention. The side view of the chair concerning the embodiment. Action | operation explanatory drawing of the chair concerning the embodiment. The side view which expands and shows a part of back frame of the embodiment. The side view which expands and shows a part of back frame of the embodiment. The perspective view seen from the back side of the chair of 2nd Embodiment of this invention. The side view of the chair concerning the embodiment. The rear view of the chair of 3rd Embodiment of this invention. The side view of the chair concerning the embodiment. The side view which abbreviate | omits and shows a part of chair concerning the embodiment. The perspective view which expands and shows the back support member concerning the embodiment. The side view of the chair of 4th Embodiment of this invention. The bottom view of the chair concerning the embodiment. The side view of the chair of 5th Embodiment of this invention. The perspective view seen from the back side of the chair of 6th Embodiment of this invention. The perspective view which expands and shows the backrest concerning the embodiment. The perspective view seen from the back side of the chair of 7th Embodiment of this invention. The perspective view seen from the back side of the chair of 8th Embodiment of this invention. The top view which shows the principal part of the chair concerning the embodiment. The side view of the chair of 9th Embodiment of this invention. The side view which shows typically the chair of 10th Embodiment of this invention. The top view which shows typically the principal part of the chair of 11th Embodiment of this invention. The side view which shows the chair of 12th Embodiment of this invention. The perspective view seen from the back side of the chair of 13th Embodiment of this invention. The side view which expands and shows the principal part of the chair concerning the embodiment. The side view of the chair of 14th Embodiment of this invention. The figure which shows the modification of the recessed part of this invention typically. The figure which shows the modification of the recessed part of this invention typically. The figure which shows the modification of the recessed part of this invention typically. The figure which shows the modification of the recessed part of this invention typically. The figure which shows the modification of the recessed part of this invention typically. The figure which shows the modification of the recessed part of this invention typically. The figure which shows the modification of the recessed part of this invention typically. The figure which shows the modification of the recessed part of this invention typically. The bottom view of the modification. The figure which shows the modification of the recessed part of this invention typically. The figure which shows typically the modified part of the recessed part and elastomer of this invention. The figure which shows typically the modified part of the recessed part and elastomer of this invention. The figure which shows typically the modified part of the recessed part and elastomer of this invention. The figure which shows the modification of the recessed part of this invention typically. The action explanatory view of the modification. The figure which shows the modification of the recessed part of this invention typically.

<First Embodiment>
First, a first embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the present invention is applied to an office swivel chair. As shown in FIGS. 1 to 3, the chair 1 includes a leg 2, a seat 4 supported by the leg 2 via a support mechanism 3, and a backrest 5 supported by the seat 4. It has.

  As shown in FIGS. 1 to 3, the leg body 2 includes a leg blade 21 having a caster 23 attached to the tip, and a leg column 22 erected from the leg blade 21. The support mechanism 3 includes a support base 31 provided on the leg struts 22 and arms 32 erected upward from both left and right ends of the support base 31. Left and right support shafts 321 are provided at the upper ends of the left and right arms 32 so that their axis centers coincide with each other, and the seat 4 is supported by the support shafts 321 so as to be able to perform a balance operation. Here, the “balance operation” means that the seat 4 tilts backward when the seated person's load is applied rearward around the support shaft 321 and the rear end side is lowered and the front end side is raised, When the load is applied forward, the seat 4 returns to the initial state and the front end side is lowered and the rear end side is raised. The axis is directed in the left-right direction of the chair 1.

  As shown in FIGS. 1 to 3, the seat 4 includes a pair of seat frames 41 and a mesh-like tension fabric 42 stretched between the seat frames 41. The frame 41 is pivotally supported by the arm 32 so as to be able to perform a balance operation around a single axis extending in the left-right direction. The left and right seat frames 41 are integrally formed of a hard synthetic resin, and are mainly composed of the hard portion 11. More specifically, a pair of opposing surfaces 113 having an open end 113a side are integrally provided at a portion of the seat frame 41, which is a structural material that is elastically deformed by receiving a load, and the seat frame 41 is elastically deformed. At this time, the front end 113a side of the facing surface 113 is brought close to each other so that the elastic deformation characteristics of the seat frame 41 change. That is, the seat frame 41 includes the hard portion 11 that is elastically deformed when a load is applied, and a concave portion 112 is formed on a surface that receives compressive stress due to elastic deformation of the hard portion 11, that is, a downward surface 411. And a pair of opposing surfaces 113 that come close to each other along with the elastic deformation are formed inside the recessed portion 112, and the opposing surfaces 113 are in direct contact with each other when the hard portion 11 is elastically deformed more than a certain amount. The deformation of the hard part 11 exceeding the elastic deformation limit is suppressed. In other words, the seat frame 41 includes the hard portion 11 that elastically deforms in the bending direction when a load is applied, and the pair that approaches the inside along with the elastic deformation as viewed from the bending direction of the hard portion 11. The opposing surface 113 which forms is formed. The inner side when viewed from the bending direction is the side on which the internal stress in the compression direction increases as a load is applied and the bending deformation progresses, and the center of curvature when bending in the direction in which the radius of curvature increases And the opposite side. The seat frame 41 is a cantilever-like structural material, and the side opposite to the side on which the load is applied when seated is the inside of the elastic deformation. In this embodiment, a recessed portion 112 is formed on the downward surface 411 of the rear half portion 412 of the seat frame 41, and the elastomer 12 is partially disposed on the recessed portion 112. In other words, the seat frame 41 includes a recessed portion 112 that forms the facing surface 113, and the elastomer 12 is disposed on a part of the recessed portion 112. The recessed portion 112 is open to the downward surface 411 of the hard portion 11 and both side surfaces 117 continuing to the downward surface 411, and a part of the inner side of the recessed portion 112 that faces is used as the facing surface 113. Yes. In other words, the recessed portion 112 has a larger opening width 116 on the back side than the opening width 115 on the opening end side, and the inner side on the opening end 114 side serves as the facing surface 113. In other words, the hard portion 11 includes a thin portion 91 and thick portions 92 that are provided on both sides of the thin portion 91 and have a thickness dimension larger than that of the thin portion 91. The recessed portion 112 is formed between the portions 92, and the facing surface 113 is formed inside the recessed portion 112. A back frame 51 of the backrest 5 is provided integrally and continuously at the rear end of the seat frame 41.

  As shown in FIGS. 1 to 3, the backrest 5 includes a back frame 51 that forms a pair, and a mesh-like tension fabric 52 that is stretched between the back frames 51. The left and right back frames 51 are each integrally formed of a hard synthetic resin, and are mainly composed of the hard portion 13. More specifically, a pair of opposing surfaces 133 with the distal end 133a open are integrally provided on the elastically deformed portion of the back frame 51, which is a structural material that is elastically deformed under a load, and the back frame 51 is elastically deformed. At this time, the front end 133a side of the facing surface 133 is close to the elastic frame, and the elastic deformation characteristics of the back frame 51 are changed. That is, the back frame 51 includes the hard portion 13 that is elastically deformed when a load is applied, and a concave portion 132 is formed on a surface that receives compressive stress due to elastic deformation of the hard portion 13, that is, the back surface 511. And forming a pair of opposed surfaces 133 that approach each other along with the elastic deformation inside the recessed portion 132, and when the hard portion 13 is elastically deformed more than a certain amount, the opposed surfaces 133 are in direct contact with each other, The deformation of the hard portion 13 beyond the elastic deformation limit is suppressed. In other words, the back frame 51 includes the hard portion 13 that elastically deforms in the bending direction when a load is applied, and the pair that approaches the inside along with the elastic deformation as viewed from the bending direction of the hard portion 13. The opposing surface 133 which forms is formed. The inner side when viewed from the bending direction is the side on which the internal stress in the compression direction increases as the bending deformation progresses as a load is applied, and the center of curvature when bending in a direction in which the radius of curvature decreases Point to the side. The back frame 51 is a cantilever-like structural material, and the side opposite to the side on which the load is applied when seated is the inside of the elastic deformation. In this embodiment, a recessed portion 132 is formed on the back surface 511 of the back frame 51, and the elastomer 14 is partially disposed on the recessed portion 132. In other words, the back frame 51 includes a recessed portion 132 that forms the facing surface 133, and the elastomer 14 is disposed on a part of the recessed portion 132. The recessed portion 132 is open to the back surface 511 of the hard portion 13 and both side surfaces 137 continuous to the back surface 511, and a part of the inside of the recessed portion 132 that faces is the facing surface 133. That is, the recessed portion 132 has a larger opening width 136 on the back side than the opening width 135 on the opening end side, and the inner side on the opening end 134 side serves as the facing surface 133. In other words, the hard part 13 includes a thin part 93 and a thick part 94 provided on both sides of the thin part 93 and having a thickness dimension larger than that of the thin part 93. The recessed portion 132 is formed between the portions 94, and the facing surface 133 is formed inside the recessed portion 132. 4 and 5 show the hard portion 13 and the elastomer 14 of the back frame 51 before and after elastic deformation in an enlarged manner, and the hard portion 11 and the elastomer 12 of the seat frame 41 also conform to this. Deformation is made.

  As described above, the seat frame 41 and the back frame 51 include the hard portions 11 and 13 that are elastically deformed when a load is applied. Recessed portions 112 and 132 are provided on the inner surface when viewed from the direction, and opposing surfaces 113 and 133 that form a pair approaching with the elastic deformation are provided on the inner sides of the recessed portions 112 and 132, respectively. As long as no excessive force is applied to the seat frame 41 and the back frame 51 in a state in which the opposing surfaces 113 and 133 are in contact with each other, the predetermined deformed shape as shown in FIG. 3 is maintained. ing.

  The chair 1 also includes a rotation restricting mechanism 6 that restricts the balance operation of the left and right seat frames 41 within a certain range. As shown in FIGS. 1 to 3, the rotation restricting mechanism 6 is attached to the protrusion 61 provided on the arm 32 of the support base 31 and the downward surface 411 of the seat frame 41 and contacts the protrusion 61. The abutment 62 is made of an elastomer.

  In the case of such a chair 1, various seating feelings can be obtained by combining the sinking operation of the seat frame 41, the backward tilting operation of the back frame 51, and the elastic deformation of the seat frame 41 and the back frame 51 itself. . That is, when sitting on the seat 4 in the office posture (S), as shown in FIGS. 1 and 2, the load caused by the weight of the seated person acts on the front region F of the seat 4. The frame 41 does not tilt and the seat 4 is supported in a stable state. Further, when the seated person leans on the backrest 5 and the load shifts to the rear region R of the seat 4, the seat frame 41 performs a balance operation, and the rear region R of the seat 4 sinks.

  Then, when the seated person leans further deeply into the backrest 5, as shown in FIG. 3, the hard portions 11 and 13 of the seat frame 41 and the back frame 51 are elastically deformed, and the seated person is softly received. This elastic deformation is mainly governed by the elastic characteristics of the thin portions 91 and 93 until the opposing surfaces 113 and 133 of the recessed portions 112 and 132 come into contact with each other. After the contact 133, the deformation of the thin portions 91 and 93 is prohibited, and the elastic properties of the thick portions 92 and 94 are governed. That is, the elastic deformation characteristics of the hard portions 11 and 13 change suddenly before and after the opposing surfaces 113 and 133 come into contact with each other. Tilt is deterred. Even after the hard portions 11 and 13 reach the elastic deformation limit and the opposing surfaces 113 and 133 come into contact with each other, if an excessive backward tilting force is applied to the backrest 5, the seat frame 41 and Slight deformation is performed while being controlled by the elastic characteristics of the thick portions 92 and 94 of the hard portions 11 and 13 of the back frame 51. That is, when the hard portions 11 and 13 in the seat frame 41 and the back frame 51 reach the elastic deformation limit, the elastomers 12 and 14 disposed in the recessed portions 112 and 132 are compressed, and the opposing surface 113 is compressed. 133 will contact directly. Therefore, further elastic deformation of the seat frame 41 and the back frame 51 is suppressed.

  In addition, in this embodiment, the seat frame 41 and the back frame 51 are provided with recessed portions 112 and 132, respectively, and when the hard portions 11 and 13 are deformed to a predetermined elastic deformation limit, Since the opposed surfaces 113 and 133 of 132 are in direct contact with each other and the deformation of the hard portions 11 and 13 exceeding the elastic deformation limit is suppressed, the opposed surfaces 113 and 133 are in contact with each other. In this state, the seat frame 41 and the back frame 51 are kept in a preset deformed shape unless an excessive force is applied.

  The final deformed shape of the seat frame 41 and the back frame 51 can be freely designed by appropriately selecting the arrangement interval, shape, size, and the like of the recessed portions 112 and 132. Further, the timing of elastic deformation of the seat frame 41 and the back frame 51 is not limited to that described above, and can be variously changed.

  Since the seat frame 41 and the back frame 51 of the present embodiment are elastically deformed on the side opposite to the side on which a load is applied when seated, a seated person's clothes are sandwiched between the facing surfaces 113 and 133. There is no fear of it.

  Further, in such a chair 1, the left and right seat frames 41 and the back frame 51 can be independently tilted backward, and therefore, it is possible to cope with a backward twisting motion of the seated person. That is, the seat frame 41 and the back frame 51 can perform the balance operation separately on the left and right sides, and can elastically deform the seat frame 41 and the back frame 51 separately on the left and right sides. In addition, as long as it does not prevent the left and right seat frames 41 and the back frame 51 from independently tilting backward, a horizontal frame or the like that connects the left and right back frames 51 may be provided. Furthermore, in the chair 1 of the present embodiment, the positions where the recessed portions 112 in the left and right seat frames 41 are set at the same front and rear positions on the left and right, and the positions where the recessed portions 132 in the left and right back frames 51 are provided at the same height on the left and right Since it is set to the vertical position, the chair 1 can be balanced on the left and right.

  In this embodiment, the recessed portion 112 is provided only in the rear half portion 412 of the seat frame 41. However, a recessed portion may be provided in the front half portion of the seat frame.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the present invention is applied to an office swivel chair. As shown in FIGS. 6 and 7, the chair 1 includes a leg body 2, a seat 4 supported by the leg body 2 via a support mechanism 3, and a backrest 5 supported by the seat 4. It has.

  As shown in FIGS. 6 and 7, the leg body 2 includes a leg blade 21 having a caster 23 attached to the tip, and a leg column 22 erected from the leg blade 21. The support mechanism 3 includes a support base 31 provided on the leg support 22, and a front link element 34 that forms a left-right pair with a base end pivotally attached to the front end of the support base 31 via a front horizontal shaft 33. A pair of left and right rear link elements 36 pivotally attached to the rear end of the support base 31 via a rear horizontal shaft 35, and the base link so as to rotate integrally with the rear link element 36. A back frame support member 37 having an end fixed to the rear link element 36 and a front end extending to the back surface 511 side of the backrest 5 is provided. An upper end 38 of the front link element 34 and an upper end 39 of the rear link element 36 are respectively pivotally attached to a seat frame 41 of the seat 4, and the support base 31, the front link element 34, the seat frame 41, and the rear frame are supported. The link element 36 forms a four-bar linkage mechanism.

  As shown in FIGS. 6 and 7, the seat 4 includes a pair of left and right seat frames 41 and a mesh-like tension fabric 42 stretched between the seat frames 41. The frame 41 includes a hard portion 11 and a recessed portion 112 provided in the hard portion 11 according to the first embodiment, and forms a pair that approaches the inside of the recessed portion 112 with the elastic deformation. An opposing surface 113 is formed, and when the hard portion 11 is elastically deformed more than a certain amount, the opposing surfaces 113 are in direct contact with each other to prevent deformation of the hard portion 11 beyond the elastic deformation limit. Therefore, the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. In addition, if it demonstrates about a different point from 1st Embodiment, the front bearing 413 and the rear bearing 414 are provided in the downward surface 411 of the seat frame 41 at intervals in the front-back direction, and the said front bearing 413 has the said An upper end 38 of the front link element 34 is pivotally attached, and an upper end 39 of the rear link element 36 is pivotally attached to the rear bearing 414.

  As shown in FIGS. 6 and 7, the backrest 5 includes a back frame 51 that forms a pair of left and right sides, and a mesh-like tension fabric 52 that is stretched between the back frames 51. The back frame 51 includes a hard portion 13 and a recessed portion 132 provided in the hard portion 13 according to the first embodiment, and a pair that approaches the inside of the recessed portion 132 with the elastic deformation. An opposing surface 133 is formed, and when the hard portion 13 is elastically deformed more than a certain amount, the opposing surfaces 133 are in direct contact with each other to prevent deformation of the hard portion 13 beyond the elastic deformation limit. The same or corresponding parts as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted. The difference from the first embodiment will be described. A housing 512 that opens downward is provided on the back surface 511 side of the back frame 51, and the upper end portion 30 of the back frame support member 37 is inserted into the housing 512. ing. The upper end portion 30 of the back frame support member 37 is provided with a long hole 301 extending in the vertical direction, and a horizontal shaft 513 fixed to the housing 512 is passed through the long hole 301. Thus, the upper end portion 30 of the back frame support member 37 is connected to the back frame 51 in a state in which the upper end portion 30 can freely move up and down by a certain dimension.

  In the case of such a chair 1, various seating feelings can be obtained by combining the sinking operation of the seat frame 41, the backward tilting operation of the back frame 51, and the elastic deformation of the seat frame 41 and the back frame 51. That is, when sitting on the seat 4 in the office posture (S), as indicated by the solid line in FIGS. 6 and 7, the load caused by the weight of the seated person acts in the direction of pushing down the seat 4, so The frame 41 and the back frame 51 do not tilt, and the seat 4 is supported in a stable state. When the seated person leans on the backrest 5 and the backrest 5 is urged backward, the backrest 5 tilts backward while rotating the back frame support member 37 backward. As a result, the rear link element 36 rotates rearward to raise the seat 4 rearward and upward, and the front link element 34 also rotates rearward as the seat 4 moves. Since the front link element 34 and the rear link element 36 are slightly inclined forward in the office posture (S), the seat 4 is lifted upward as it rotates backward, and the center of gravity of the seated person is moved upward. I will let you. That is, the chair 1 is provided with a weight sensing type link mechanism, and can return to the working posture (S) using the weight of the seated person.

  When the seated person leans further deeply into the backrest 5 from the above-mentioned backward tilted posture, the hard portions 11 and 13 of the seat frame 41 and the back frame 51 are elastically deformed as shown by a two-dot chain line in FIG. , Will take the seated person softly. This elastic deformation is the same as that of the first embodiment, and the elastic deformation characteristics of the hard portions 11 and 13 change suddenly before and after the opposing surfaces 113 and 133 come into contact with each other. After the contact, the backrest 5 is prevented from tilting further backward. That is, when the hard portions 11 and 13 in the seat frame 41 and the back frame 51 are elastically deformed more than a certain amount, the elastomers 12 and 14 disposed in the recessed portions 112 and 132 are compressed, and the opposing surfaces 113 and 133 are It will contact directly. Therefore, further elastic deformation of the seat frame 41 and the back frame 51 is suppressed. Moreover, in this embodiment, the recessed portions 112 and 132 are provided in the seat frame 41 and the back frame 51, respectively, and when the hard portions 11 and 13 are elastically deformed more than a certain amount, the opposed portions 112 and 132 face each other. Since the surfaces 113 and 133 are in direct contact with each other and the deformation exceeding the elastic deformation limit of the hard portions 11 and 13 is suppressed, the respective facing surfaces 113 and 133 are in contact with each other, As long as no excessive force is applied, the seat frame 41 and the back frame 51 are kept in a preset deformed shape.

  The final deformed shape of the seat frame 41 and the back frame 51 can be freely designed by appropriately selecting the arrangement interval, shape, size, and the like of the recessed portions 112 and 132. Further, the timing of elastic deformation of the seat frame 41 and the back frame 51 is not limited to that described above, and can be variously changed.

  As in the first embodiment, the seat frame 41 and the back frame 51 of the present embodiment are such that the side opposite to the side on which the load is applied when seated is the inner side of the elastic deformation. There is no risk of the user's clothes being pinched.

  Further, in the case of such a chair 1, as in the first embodiment, the left and right seat frames 41 and the back frame 51 can be tilted independently of each other, so that the seated person can also twist backward. Can respond. That is, the seat frame 41 and the back frame 51 can perform the balance operation separately on the left and right sides, and can elastically deform the seat frame 41 and the back frame 51 separately on the left and right sides. In addition, as long as it does not prevent the left and right seat frames 41 and the back frame 51 from independently tilting backward, a horizontal frame or the like that connects the left and right back frames 51 may be provided. Furthermore, in the chair 1 of the present embodiment, the positions where the recessed portions 112 in the left and right seat frames 41 are set at the same front and rear positions on the left and right, and the positions where the recessed portions 132 in the left and right back frames 51 are provided at the same height on the left and right Since it is set to the vertical position, the chair 1 can be balanced on the left and right.

  In this embodiment, the recessed portion 112 is provided only in the rear half portion 412 of the seat frame 41. However, a recessed portion may be provided in the front half portion of the seat frame.

<Third Embodiment>
Next, a third embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the present invention is applied to an office swivel chair. As shown in FIGS. 8 to 10, the chair 1 includes a leg 2, a seat 4 supported by the leg 2 via a support mechanism 3, and a back support member 7 attached to the leg 2. The back support member 7 is supported by a back support member lower portion 71 and pivotally attached to the upper end of the back support member lower portion 71 so as to be able to tilt backward within a certain angle range. The back support member upper part 72 is provided.

  As shown in FIGS. 8 and 9, the leg body 2 is provided with a leg blade 21 having a caster 23 attached to the tip thereof and a leg column 22 erected from the leg blade 21. As shown in FIGS. 8 to 10, the support mechanism 3 operates to synchronize the seat 4 and the backrest 5, for example, a support base 31 provided on the leg column 22, A seat receiver 311 provided above the support base 31, a slide support portion 312 that supports the front end of the seat receiver 311 to be slidable in the front-rear direction on the support base 31, and the seat receiver 311 A pivot part 313 for rotatably supporting the rear end part on the lower part 71 of the back support member is provided.

  As shown in FIGS. 8 and 9, the seat 4 is arranged on the seat receiver 311 so that the front and rear positions can be adjusted. An inner shell (not shown) supported by the seat receiver 311, and an inner shell on the inner shell are arranged. It comprises a cushion (not shown) provided and a tension fabric 42 provided so as to cover the cushion.

  As shown in FIGS. 8 to 10, the backrest 5 is formed by arranging an inner shell and a cushion (not shown) on the front side of the outer shell 53, and the lower end portion of the outer shell 53 is disposed below the back support member. The upper back surface of the outer shell 53 is supported on the upper portion 72 of the back support member via the slide connecting portion 530. The slide connecting portion 530 connects the upper end of the back support member 7, more specifically, the upper end of the back support member upper portion 72 and the outer shell 53 so as to be relatively movable in the vertical direction. Each of the outer shell 53 and the inner shell is elastically deformable, and is formed of, for example, a synthetic resin.

  As shown in FIGS. 8 to 11, the back support member 7 is fixed to the back support member lower portion 71 whose base end portion is supported by the support base portion 31 so as to be able to tilt backward, and to the upper end of the back support member lower portion 71. And a back support member upper part 72 pivotally mounted so as to be able to tilt backward in the angular range. The back support member lower portion 71 is made of metal, and the back support member upper portion 72 is made of a hard synthetic resin, and mainly includes the hard portion 11. More specifically, a pair of opposing surfaces 113 with the distal end 113a open are integrally provided at the elastically deforming portion of the back support member upper portion 72, which is a structural material that is elastically deformed in response to a load, and the back support member upper portion 72 is provided. When elastically deforming, the front end 113a side of the facing surface 113 comes close to the elastic deformation characteristic of the upper portion 72 of the back support member. As shown in an enlarged view in FIG. 11, the middle region 722 of the back support member upper portion 72 is a flat surface having a front wall 723 and left and right side walls 724 extending rearward from both side edges of the front wall 723. It has a U-shaped cross section. More specifically, each of the side walls 724 includes the hard portion 11 that is elastically deformed when a load is applied thereto. A concave portion 112 is provided, and a pair of opposing surfaces 113 are formed on the inner side of the concave portion 112 along with the elastic deformation. When the hard portion 11 is elastically deformed more than a certain amount, the opposing surfaces 113 are directly connected to each other. The deformation of the hard part 11 beyond the elastic deformation limit is suppressed by abutting. That is, the upper portion 72 of the back support member includes the hard portion 11 that elastically deforms in the bending direction when a load is applied, and approaches the inner side in accordance with the elastic deformation as viewed from the bending direction of the hard portion 11. The opposing surfaces 113 forming a pair are formed. The inner side when viewed from the bending direction is the side on which the internal stress in the compression direction increases as the bending deformation progresses as a load is applied, and the center of curvature when bending in a direction in which the radius of curvature decreases Point to the side. The upper portion 72 of the back support member is a cantilever-like structural material, and the side opposite to the side on which the load is applied when seated is the inside of the elastic deformation. In this embodiment, a recessed portion 112 is formed on the back surface 721 of each side wall 724 in the intermediate region 722 of the back support member upper portion 72, and the elastomer 12 is partially disposed in each of the recessed portions 112. In other words, the back support member upper portion 72 includes a recessed portion 112 that forms the facing surface 113, and the elastomer 12 is disposed on a part of the recessed portion 112. The recessed portion 112 is open to the back surface 721 of the side wall 724 mainly composed of the hard portion 11 and both side surfaces 117 continuous to the back surface 721. The facing surface 113 is used. In other words, the recessed portion 112 has a larger opening width 116 on the back side than the opening width 115 on the opening end side, and the inner side on the opening end 114 side serves as the facing surface 113. In other words, the hard portion 11 includes a thin portion 91 and thick portions 92 that are provided on both sides of the thin portion 91 and have a thickness dimension larger than that of the thin portion 91. The recessed portion 112 is formed between the portions 92, and the facing surface 113 is formed inside the recessed portion 112.

  As shown in FIG. 10, the back support member lower portion 71 is biased in a direction to return to the working posture (S) by a first reaction force spring 314 disposed in the support base 31. The back support member upper portion 72 is urged in a direction to return to the office posture (S) by a second reaction force spring 73 disposed between the back support member lower portion 71 and the back support member lower portion 71. That is, the back support member upper part 72 is biased forward with respect to the back support member lower part 71. The urging force of the first reaction force spring 314 and the urging force of the second reaction force spring 73 are such that, for example, when a backward load is applied to the backrest 5, the back support member upper portion 72 first supports the back. The value is set such that the back support member upper portion 72 and the back support member lower portion 71 are tilted backward with respect to the member lower portion 71 after being tilted backward to near the rear tilt limit position.

  In the case of such a chair 1, various support forms of the backrest 5 can be obtained by combining the normal backward tilting operation of the back support member 7 and the elastic deformation of the upper portion 72 of the back support member. That is, when the seated person leans on the backrest 5 from the office posture (S) shown in FIG. 9 and a backward load acts on the backrest 5, first, the back support member upper part 72 is the back support member lower part 71. In contrast, the second reaction force spring 73 tilts backward against the urging force of the second reaction force spring 73. When a rearward load is applied from a state in which the back support member upper part 72 is tilted back to a position near the rearward tilt limit position, the back support member upper part 72 and the back support member lower part 71 are biased by the first reaction force spring 314. Against the back, lean backward and reach a repose.

  In this repose posture state, when a larger rearward load is applied, the hard portion 11 of the back support member upper portion 72 is elastically deformed, and the seated person is softly received. This elastic deformation is the same as that of the first embodiment, and the elastic deformation characteristics of the hard portion 11 change suddenly before and after the opposing surfaces 113 come into contact with each other. It is possible to prevent the backrest 5 from tilting further backward. That is, when the hard part 11 in the upper part 72 of the back support member is elastically deformed more than a certain amount, the elastomer 12 disposed in each recessed part 112 is compressed, and the opposing surfaces 113 come into direct contact with each other. For this reason, further elastic deformation of the upper portion 72 of the back support member is suppressed.

  In addition, the chair 1 of the present embodiment is set at the same height position on the left and right side walls 714 at the positions where the recessed portions 112 in the left and right back support member upper portions 72 are provided. can do.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the present invention is applied to a so-called four-leg pipe chair. As shown in FIGS. 12 and 13, the chair 1 includes a leg body 2, a seat 4 supported by the leg body 2, and a backrest 5 supported by the seat 4.

  As shown in FIGS. 12 and 13, the leg body 2 includes front and rear legs 24 and 25 and a seat receiving portion 26 that connects the upper ends of the front and rear legs 24 and 25, respectively. . The front and rear legs 24 and 25 and the seat receiving portion 26 are made by bending one pipe. The seat receiving portion 26 is provided so as to be continuous with the horizontal portion 261 that supports the front region F of the seat 4 and the horizontal portion 261, and is inclined so as to allow a sinking operation of the rear region R of the seat 4. And an inclined portion 262. A front region F of the seat 4 is fixed to the horizontal portion 261 of the seat receiving portion 26 via a fastener.

  As shown in FIGS. 12 and 13, the seat 4 has a shell shape, is integrally formed of a hard synthetic resin, and mainly includes the hard portion 11. More specifically, when the seat 4 is elastically deformed when the seat 4 is elastically deformed, a pair of opposing surfaces 113 with the distal end 113a open are integrally provided at a portion of the seat 4 which is elastically deformed under load. The front end 113a side of the facing surface 113 is close to each other so that the elastic deformation characteristics of the seat 4 change. That is, the seat 4 includes the hard portion 11 that is elastically deformed when a load is applied, and a concave portion 112 is formed on a surface that receives compressive stress due to the elastic deformation of the hard portion 11, that is, a downward surface 411. A pair of opposing surfaces 113 that are close together with the elastic deformation are formed inside the recessed portion 112, and the opposing surfaces 113 are in direct contact with each other when the hard portion 11 is elastically deformed more than a certain amount, The deformation of the hard portion 11 beyond the elastic deformation limit is suppressed. That is, the seat 4 includes a hard portion 11 that elastically deforms in the bending direction when a load is applied, and a pair that approaches the inside along with the elastic deformation as viewed from the bending direction of the hard portion 11. The opposing surface 113 is formed. The inner side when viewed from the bending direction is the side on which the internal stress in the compression direction increases as the bending deformation progresses as a load is applied, and the center of curvature when bending in a direction in which the radius of curvature decreases Point to the side. The side opposite to the side on which the load is applied when seated is the inside of the elastic deformation. In this embodiment, a single recessed portion 112 is formed on the downward surface 411 of the seat 4, and the elastomer 12 is partially disposed on the recessed portion 112. The seat 4 includes a recessed portion 112 that forms the facing surface 113, and the elastomer 12 is disposed on a part of the recessed portion 112. The recessed portion 112 is formed at a boundary that divides the front region F and the rear region R of the seat 4. That is, the recessed portion 112 is formed from one side end to the other side end of the seat 4, and is continuous with the downward surface of the hard portion 11, that is, the downward surface 411 of the seat 4 and the downward surface 411. The opposite side surfaces 117 of the seat 4 are opened on both side surfaces 117, and a part of the inner side of the concave portion 112 facing each other is used as the opposing surface 113. In other words, the recessed portion 112 has a larger opening width 116 on the back side than the opening width 115 on the opening end side, and the inner side on the opening end 114 side serves as the facing surface 113. In other words, the hard portion 11 includes a thin portion 91 and thick portions 92 that are provided on both sides of the thin portion 91 and have a thickness dimension larger than that of the thin portion 91. The recessed portion 112 is formed between the portions 92, and the facing surface 113 is formed inside the recessed portion 112. In addition, as shown in this embodiment, the front-end | tip 113a of the opposing surface 113 may have a length from the end of a member to an end. A backrest 5 is integrally provided continuously at the rear end of the seat 4.

  The backrest 5 has a shell shape as shown in FIGS. 12 and 13 and is made of, for example, a synthetic resin.

  With such a chair 1, a variety of seating feelings can be obtained by combining the sinking operation of the seat 4, the backward tilting operation of the backrest 5, and the elastic deformation of the seat 4. That is, when sitting on the seat 4 in the office posture (S), the load caused by the weight of the seated person acts on the front region F of the seat 4 as shown by the solid line in FIG. Does not tilt, and the seat 4 is supported in a stable state. Further, when the seated person leans on the backrest 5 and the load shifts to the rear region R of the seat 4, the vicinity of the recessed portion 112 where the elastomer 12 is arranged in the seat 4 is significantly elastically deformed, The rear region R will sink. This elastic deformation is the same as that of the first embodiment, and the elastic deformation characteristics of the hard portion 11 change suddenly before and after the opposing surfaces 113 come into contact with each other. It is possible to prevent the backrest 5 from tilting further backward. That is, when the seated person leans deeper into the backrest 5 and the hard portion 11 in the seat 4 reaches the elastic deformation limit, as shown by a two-dot chain line in FIG. The disposed elastomer 12 is compressed, and the opposing surfaces 113 come into direct contact with each other. Therefore, further elastic deformation of the seat 4 is suppressed, and further depression of the seat 4 cannot be performed. In this embodiment, when an unexpected shock load acts and the rear region R of the seat 4 further sinks, the lower surface of the rear region R of the seat 4 is the inclined portion 262 of the seat receiving portion 26. It comes to contact with.

  Further, in the present embodiment, since the recessed portion 112 is provided in the left-right direction at the boundary between the front region F and the rear region R, the rear region R sinks in response to the backward twisting motion of the seated person. And the elastic deformation of the seat can be performed. Furthermore, the chair 1 of this embodiment does not need to be provided with a special stopper or the like for locking the sinking operation of the seat 4 outside the seat 4, and the seat 4 suppresses elastic deformation with a certain sinking amount. It has a possible structure.

  In the present embodiment, the recessed portion 112 is provided only on the seat 4. However, a recessed portion may be provided on the backrest or on the boundary between the seat and the backrest.

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described with reference to FIG.

  In this embodiment, the present invention is applied to a so-called four-legged pipe chair 1. As shown in FIG. 14, the chair 1 includes a leg 2, a seat 4 supported by the leg 2, and a backrest 5 supported by the seat 4. Parts that are the same as or equivalent to those in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  In this embodiment, no elastomer is disposed in the recessed portion 112 of the seat 4.

  With such a chair 1, a variety of seating feelings can be obtained by combining the sinking operation of the seat 4, the backward tilting operation of the backrest 5, and the elastic deformation of the seat 4. That is, when sitting on the seat 4 in the office posture (S), as shown by the solid line in FIG. 14, the load caused by the weight of the seated person acts on the front region F of the seat 4, so Does not tilt, and the seat 4 is supported in a stable state. In addition, when the seated person leans on the backrest 5 and the load shifts to the rear region R of the seat 4, the vicinity of the recessed portion 112 in the seat 4 is significantly elastically deformed, and the rear region R sinks. Become. This elastic deformation is the same as that of the first embodiment, and the elastic deformation characteristics of the hard portion 11 change suddenly before and after the opposing surfaces 113 come into contact with each other. It is possible to prevent the backrest 5 from tilting further backward. That is, when the seated person leans deeper into the backrest 5 and the hard portion 11 in the seat 4 reaches the elastic deformation limit, as shown by a two-dot chain line in FIG. The facing surface 113 comes into direct contact. Therefore, further elastic deformation of the seat 4 is suppressed, and further depression of the seat 4 cannot be performed. Therefore, with such a configuration, it is not necessary to provide a special stopper or the like for locking the sinking operation of the seat 4 outside the seat 4, and the configuration can be simplified.

<Sixth Embodiment>
Next, a sixth embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the present invention is applied to a so-called cantilever type pipe chair. As shown in FIGS. 15 and 16, the chair 1 includes a leg body 2, a seat 4 supported by the leg body 2, and a backrest 5 supported by the seat 4.

  As shown in FIG. 15, the leg 2 includes a U-shaped base 27, legs 28 erected from both left and right ends of the base 27, and seat receiving portions 26 extending rearward from the upper ends of the legs 28. In this embodiment, the base 27, the leg 28 and the seat receiving portion 26 are made by bending a single pipe. The seat receiving portion 26 is for supporting the front region F of the seat 4, and the front region F of the seat 4 is fixed to the seat receiving portion 26 via a fastener.

  As shown in FIGS. 15 and 16, the seat 4 includes a shell-like seat body 431 and ribs 432 and 433 formed on the downward surface 411 of the seat body 431. The ribs 432 and 433 are integrally formed of a hard synthetic resin, and the seat 4 is mainly composed of the hard portion 11. More specifically, when the seat 4 is elastically deformed when the seat 4 is elastically deformed, a pair of opposing surfaces 113 with the distal end 113a open are integrally provided at a portion of the seat 4 which is elastically deformed under load. The front end 113a side of the facing surface 113 is close to each other so that the elastic deformation characteristics of the seat 4 change. That is, the seat 4 includes the hard portion 11 that is elastically deformed when a load is applied, and a concave portion 112 is formed on a surface that receives compressive stress due to the elastic deformation of the hard portion 11, that is, a downward surface 411. A pair of opposing surfaces 113 that are close together with the elastic deformation are formed inside the recessed portion 112, and the opposing surfaces 113 are in direct contact with each other when the hard portion 11 is elastically deformed more than a certain amount, The deformation of the hard portion 11 beyond the elastic deformation limit is suppressed. That is, the seat 4 includes a hard portion 11 that elastically deforms in the bending direction when a load is applied, and a pair that approaches the inside along with the elastic deformation as viewed from the bending direction of the hard portion 11. The opposing surface 113 is formed. The inner side when viewed from the bending direction is the side on which the internal stress in the compression direction increases as a load is applied and the bending deformation progresses, and the center of curvature when bending in the direction in which the radius of curvature increases And the opposite side. The side opposite to the side on which the load is applied when seated is the inside of the elastic deformation. In this embodiment, the seat 4 has left and right ribs 433 formed in the vicinity of both sides of the downward surface 411 of the seat body 431 and a central rib 432 formed in the center portion in the left and right direction of the seat body 431. It is. The left and right ribs 433 are formed from the front region F to the rear region R of the seat 4, and the central rib 432 is formed in the rear region R of the seat 4. The recessed portion 112 is formed in a portion located in the rear region R of the ribs 432 and 433, and the elastomer 12 is partially disposed on the recessed portion 112. The seat 4 includes a recessed portion 112 that forms the facing surface 113, and the elastomer 12 is disposed on a part of the recessed portion 112. The recessed portion 112 is open to the downward surface 411 of the hard portion 11, that is, the downward surface of the ribs 432 and 433, and both side surfaces 117 continuous to the downward surface, that is, both side surfaces 117 of the ribs 432 and 433. A part of the inside of the recessed portion 112 that faces the concave portion 112 is used as the facing surface 113. The recessed portion 112 has a larger opening width 116 on the back side than the opening width 115 on the opening end side, and the inside on the opening end 114 side serves as the facing surface 113. In other words, the hard portion 11 includes a thin portion 91 and thick portions 92 that are provided on both sides of the thin portion 91 and have a thickness dimension larger than that of the thin portion 91. A recessed portion 112 is formed between the portions 92, and the facing surface 113 is formed inside the recessed portion 112. A backrest 5 is integrally provided continuously at the rear end of the seat 4.

  As shown in FIGS. 15 and 16, the backrest 5 includes a shell-like back body 531 and ribs 532 and 533 formed on the back surface 511 of the back body 531. The ribs 532 and 533 are integrally formed of a hard synthetic resin, and the backrest 5 is mainly composed of the hard portion 13. More specifically, a pair of opposing surfaces 133 with the distal end 133a open are integrally provided on the elastically deformed portion of the backrest 5 that is a structural material that elastically deforms under load, and the backrest 5 is elastically deformed. In this case, the tip 133a side of the facing surface 133 is close to the back surface 5 so that the elastic deformation characteristics of the backrest 5 change. That is, the backrest 5 includes the hard portion 13 that is elastically deformed when a load is applied, and the concave portion 132 is formed on the surface that receives the compressive stress due to the elastic deformation of the hard portion 13, that is, the back surface 511. And forming a pair of opposed surfaces 133 that approach each other along with the elastic deformation inside the recessed portion 132, and when the hard portion 13 is elastically deformed more than a certain amount, the opposed surfaces 133 are in direct contact with each other, The deformation of the hard portion 13 beyond the elastic deformation limit is suppressed. That is, the backrest 5 is provided with a hard portion 13 that elastically deforms in the bending direction when a load is applied, and the pair that approaches the inside in accordance with the elastic deformation as viewed from the bending direction of the hard portion 13. The opposing surface 133 which forms is formed. The inner side when viewed from the bending direction is the side on which the internal stress in the compression direction increases as the bending deformation progresses as a load is applied, and the center of curvature when bending in a direction in which the radius of curvature decreases Point to the side. The backrest 5 is on the inner side of the elastic deformation on the side opposite to the side on which the load is applied when sitting. In this embodiment, the backrest 5 has left and right ribs 533 formed in the vicinity of both sides of the back surface 511 of the back body 531 and a central rib 532 formed in the center portion in the left and right direction of the back body 531. It is. The left and right ribs 533 are formed continuously with the left and right ribs 433 of the seat 4, and the central rib 532 is formed continuously with the central rib 432 of the seat 4. The recessed portion 132 is formed in the ribs 532 and 533, and the elastomer 14 is partially disposed on the recessed portion 132. The backrest 5 includes a recessed portion 132 that forms the facing surface 133, and the elastomer 14 is disposed on a part of the recessed portion 132. The recessed portion 132 is open to the back surface 511 of the hard portion 13, that is, the back surface of the ribs 532 and 533, and both side surfaces 137 continuous to the back surface, that is, both side surfaces 137 of the ribs 532 and 533. A part of the inner side of the portion 132 that is opposed to the portion 132 is used as the facing surface 133. The recessed portion 132 has a larger opening width 136 on the back side than the opening width 135 on the opening end side, and the inner side on the opening end 134 side serves as the facing surface 133. In other words, the hard portion 13 includes a thin portion 93, and a thick portion 94 provided on both sides of the thin portion 93 and having a thickness dimension larger than that of the thin portion 93. A recessed portion 132 is formed between the portions 94, and the facing surface 133 is formed inside the recessed portion 132.

  With such a chair 1, a variety of seating feelings can be obtained by combining the sinking operation of the seat 4, the backward tilting operation of the backrest 5, and the elastic deformation of the seat 4. That is, when sitting on the seat 4 in the office posture (S), as shown in FIG. 17, the load caused by the weight of the seated person acts on the front region F of the seat 4, so that the seat 4 tilts. Instead, the seat 4 is supported in a stable state. Further, when the seated person leans on the backrest 5 and the load is transferred to the rear region R of the seat 4, the rear region R of the seat 4 sinks with respect to the front region F of the seat 4, and the backrest 5 will tilt backwards and will take a seated person softly. This operation is performed by elastic deformation of the hard portions 11 and 13 while the elastomers 12 and 14 in the recessed portions 112 and 132 are compressed in the seat 4 and the backrest 5. This elastic deformation is the same as that of the first embodiment, and the elastic deformation characteristics of the hard portions 11 and 13 change suddenly before and after the opposing surfaces 113 and 133 come into contact with each other. After the contact, the seat 4 and the backrest 5 are prevented from elastically deforming further. That is, when the hard portions 11 and 13 reach the elastic deformation limit, the elastomers 12 and 14 disposed in the recessed portions 112 and 132 are compressed, and the opposing surfaces 113 and 133 are in direct contact with each other. Become. Therefore, further elastic deformation of the seat 4 and the backrest 5 is suppressed. That is, the seat 4 and the backrest 5 are maintained in a preset deformed shape unless an excessive force is applied in a state where the opposing surfaces 113 and 133 are in contact with each other.

  Further, in the chair 1 of the present embodiment, the place where the recessed portion 112 in the seat 4 is provided is set to the same front and rear position by the plurality of ribs 432 and 433 adjacent in the left-right direction, and the recessed portion 132 in the backrest 5 is provided. Are set at the same height position by the plurality of ribs 532 and 533 adjacent in the left-right direction, so that the chair 1 can be balanced in the left-right direction. In addition, since a plurality of the recessed portions 112 and 132 are provided in the front-rear direction or the up-down direction, the seat 4 and the backrest 5 can be elastically deformed in response to a backward twisting operation of the seated person.

<Seventh embodiment>
Next, a seventh embodiment of the present invention will be described with reference to FIG.

  In this embodiment, the present invention is applied to a so-called cantilever type pipe chair. As shown in FIG. 17, the chair 1 comprises a leg 2, a seat 4 supported by the leg 2, and a backrest 5 supported by the seat 4. Parts that are the same as or equivalent to those in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  In this embodiment, the shapes of the recessed portion 112 of the seat 4 and the recessed portion 132 of the backrest 5 are different from those of the sixth embodiment. That is, the ribs 432 and 433 of the seat 4 in this embodiment are formed by intermittently arranging short rib elements 434 and 435, and the concave portion 112 is formed between the short rib elements 434 and 435. ing. In the recessed portion 112, the opening width 115 on the opening end side and the opening width 116 on the back side have substantially the same dimensions. And the elastomer 12 is not distribute | arranged to those recessed parts 112. FIG. The ribs 532 and 533 of the backrest 5 are formed by intermittently arranging short rib elements 534 and 535, and the concave portion 132 is formed between the short rib elements 534 and 535. In the recessed portion 132, the opening width 135 on the opening end side and the opening width 136 on the back side have substantially the same dimensions. And the elastomer 14 is not distribute | arranged to those recessed parts 132. FIG.

  If it is a thing of such a structure, the effect according to the said 7th Embodiment will be obtained.

<Eighth Embodiment>
Next, an eighth embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the present invention is applied to an office rotary chair 1. As shown in FIGS. 18 and 19, the chair 1 includes a leg body 2, a seat 4 supported by the leg body 2 through a support mechanism 3, and a back support member 7 and an elastic lateral member on the leg body 2. And a backrest 5 supported through a heel 8.

  As shown in FIG. 18, the leg body 2 includes a leg blade 21 having a caster 23 attached to the tip, and a leg column 22 erected from the leg blade 21. The support mechanism 3 operates to synchronize and tilt the seat 4 and the backrest 5. For example, the support mechanism 3 is provided on the leg support 22 and is provided above the support base 31. A seat receiver 311, a slide support portion (not shown) for supporting the front end portion of the seat receiver 311 on the front end portion of the support base 31 so as to be slidable in the front-rear direction, and the rear support portion 7 And a pivot portion (not shown) that is rotatably supported. In addition, the support mechanism 3 of this embodiment is based on the support mechanism of 3rd Embodiment shown in FIG.

  As shown in FIG. 18, the seat 4 is arranged on the seat receiver 311, an inner shell (not shown) supported by the seat receiver 311, and a cushion (not shown) provided on the inner shell, And a tension fabric 42 provided so as to cover the cushion.

  As shown in FIGS. 18 and 19, the backrest 5 includes a shell-like back main body 531 and side end mounting portions 534 provided at both right and left ends of the back main body 531. The lower end portion of 531 is fixed to the back support member 7, and the upper back surface side of the back main body 531 is supported by the back support member 7 through the elastic ledge 8. The back main body 531 is elastically deformable, and the back main body 531 and the side end attaching portion 534 are integrally formed of, for example, a synthetic resin.

  As shown in FIG. 18, the back support member 7 is configured such that the base end portion 74 is supported by the support base portion 31 so as to be capable of backward tilting, and the tip end portion 75 is connected to the elastic recumbency 8. The back support member 7 is urged forward by a reaction force mechanism (not shown) provided in the support base 31 so that when the load is no longer applied, the back support member 7 returns to its use posture.

  As shown in FIGS. 18 and 19, the elastic recumbent arm 8 includes a pair of left and right arm portions 81, and left and right attachment portions 82 that are respectively disposed at the base ends of the arm portions 81 and attached to the back support member 7. And a connecting portion 83 that elastically connects between the mounting portions 82, and the arm portion 81, the mounting portion 82, and the connecting portion 83 are integrally formed of a hard synthetic resin. These arm portions 81 are mainly composed of the hard portion 11. More specifically, a pair of opposing surfaces 113 with the distal end 113a open are integrally provided at the elastically deforming portion of the arm portion 81, which is a structural material that is elastically deformed under a load, and the arm portion 81 is elastically deformed. At this time, the distal end 113a side of the facing surface 113 is close to the arm portion 81 so that the elastic deformation characteristics of the arm portion 81 change. That is, a plurality of recessed portions 112 are provided on the back surface 811 of the hard portion 11, and the elastomer 12 is partially disposed in each of the recessed portions 112, and when the arm portion 81 is elastically deformed more than a certain amount in the rear, The opposing surfaces 113 of the recessed portion 112 are in direct contact with each other to prevent further deformation of the arm portion 81. More specifically, the hard portion 11 includes a thin portion 91 and thick portions 92 provided on both sides of the thin portion 91 and having a thickness dimension larger than that of the thin portion 91. The recessed portion 112 is formed between the meat portions 92, and the facing surface 113 is formed inside the recessed portion 112. The inner side when viewed from the bending direction in which the facing surface 113 is formed is a side on which internal stress in the compression direction increases as bending deformation progresses due to an applied load, and the bending is performed in a direction in which the radius of curvature increases. It refers to the side opposite to the center of curvature when deformed.

  In the case of such a chair 1, various support forms of the backrest 5 can be obtained by combining the normal backward tilting motion of the back support member 7 and the elastic deformation of the arm portion 81 of the elastic recumbent 8. That is, this chair 1 can not only take a working posture (S) in which the backrest 5 is erected as shown in FIG. 18 and a repose posture in which the backrest 5 is tilted backward, but also a user. The twist posture in which the backrest 5 follows the twist of the upper body can be taken. When this twisted posture is taken, the hard portion 11 of the arm portion 81 of the elastic recumbent arm 8 is elastically deformed, and the seated person is softly received. This elastic deformation is the same as that of the first embodiment, and the elastic deformation characteristics of the hard portion 11 change suddenly before and after the opposing surfaces 113 come into contact with each other. It is possible to prevent the backrest 5 from tilting further backward. That is, when the hard portion 11 in the arm portion 81 reaches the elastic deformation limit, the elastomer 12 disposed in each recessed portion 112 is compressed, and the opposing surface 113 is interposed via the compressed elastomer 12. It will abut. Therefore, further elastic deformation of the arm portion 81 is suppressed.

  Further, in such a chair 1, the left and right arm portions 81 can be elastically deformed independently of each other, so that the arm portion 81 is elastically deformed in response to the backward twisting motion of the seated person. Can do.

  Note that corresponding portions such as the opening end 114, the opening width 115 on the opening end side, the opening width 116 on the back side, and the side surface 117 in FIG. Omitted.

<Ninth Embodiment>
Next, a ninth embodiment of the present invention will be described with reference to FIG.

  In this embodiment, the present invention is applied to an office swivel chair. As shown in FIG. 20, the chair 1 includes a leg body 2, a seat 4 supported by the leg body 2 via a support mechanism 3, and a backrest 5 supported by the leg body 2. It becomes.

  As shown in FIG. 20, the leg body 2 includes a leg blade 21 having a caster 23 attached to the tip, and a leg column 22 standing from the leg blade 21. The support mechanism 3 operates to synchronize and tilt the seat 4 and the backrest 5. For example, the support mechanism 3 is provided on the leg support 22 and is provided above the support base 31. A seat receiver 311, a slide support portion (not shown) that supports the front end portion of the seat receiver 311 on the front end portion of the support base 31 so as to be slidable in the front-rear direction, and the rear end portion of the seat receiver 311 is the back support member 7. And a pivot portion that is rotatably supported.

  As shown in FIG. 20, the seat 4 is arranged on the seat receiver 311, and is composed mainly of a cushion, for example.

  As shown in FIG. 20, the backrest 5 includes left and right back frames 51 supported by the support base 31 so as to be able to tilt backward, and a back body 531 attached to the front surface of the back frame 51. Thus, the left and right back frames 51 are urged forward by a reaction force mechanism (not shown) provided in the support base 31 and are held in a predetermined initial posture by a stopper. The left and right back frames 51 include a lower frame part 54 pivotally attached to the support base 31, a top frame part 55 pivotally attached to a distal end of the lower frame part 54 via a hinge (not shown), And an elastic horizontal member 56 that joins the left and right of the left and right upper frame portions 55. The upper frame portion 55 and the lower frame portion 54 are made of metal having rigidity, and the hinge can rotate the upper frame portion 55 in the front-rear direction within a certain angle range with respect to the lower frame portion 54. It is something to support. A reaction force frame portion 57 is provided between the upper frame portion 55 and the lower frame portion 54 to urge the upper frame portion 55 forward with respect to the lower frame portion 54. The back main body 531 is formed by stretching a stretch fabric 52 on an elastically deformable backing member 535, and the backing member 535 connects the vertical frame members 536 paired to the left and right, and both the vertical frame members 536. A horizontal frame member 537 is provided. The spine main body 531 has an upper end portion fixed to the front surface of the upper frame portion 55 and a lower end portion attached to the front surface of the lower frame portion 54 so as to be slidable in the vertical direction.

  The present invention is applied to the reaction force frame portion 57 of the chair 1 as described above.

  More specifically, as shown in FIG. 20, the reaction force frame portion 57 is made of hard synthetic resin, and the lower end is fixed to the lower surface of the lower frame portion 54 and the upper end is fixed to the upper frame portion 55. It is fixed to the back of the. The reaction force frame portion 57 has a frame shape along the upper frame portion 55 and the lower frame portion 54 in a state of being separated from the upper frame portion 55 and the lower frame portion 54. The reaction force frame portion 57 is mainly composed of the hard portion 11. More specifically, the reaction force frame portion 57 that is elastically deformed by receiving a load is integrally provided with a pair of opposing surfaces 113 that are open on the tip 113a side at the elastic deformation portion of the reaction force frame portion 57. When the frame is elastically deformed, the front end 113a side of the facing surface 113 comes close to the elastic force and the elastic deformation characteristic of the reaction force frame portion 57 changes. A recessed portion 112 is provided on the back surface of the hard portion 11, that is, the back surface 571 of the reaction force frame portion 57, and the elastomer 12 is partially disposed in the recessed portion 112, and the reaction force frame portion 57 has an elastic deformation limit. When deformed, the opposing surfaces 113 of the recessed portion 112 are in direct contact with each other to prevent further deformation of the reaction force frame portion 57. More specifically, the hard portion 11 includes a thin portion 91 and thick portions 92 provided on both sides of the thin portion 91 and having a thickness dimension larger than that of the thin portion 91. The recessed portion 112 is formed between the meat portions 92, and the facing surface 113 is formed inside the recessed portion 112. The inner side when viewed from the bending direction in which the facing surface 113 is formed is a side on which internal stress in the compression direction increases as bending deformation progresses due to an applied load, and the bending is performed in a direction in which the radius of curvature decreases. It refers to the center of curvature when deformed.

  In such a chair 1, when the upper frame portion 55 is tilted backward with respect to the lower frame portion 54 from the state indicated by the solid line in FIG. 20, the hard portion 11 of the reaction force frame portion 57 accumulates repulsive force. However, it will be elastically deformed and the seated person will be received softly. This elastic deformation is the same as that of the first embodiment, and the elastic deformation characteristics of the hard portion 11 change suddenly before and after the opposing surfaces 113 come into contact with each other. It is possible to prevent the backrest 5 from tilting further backward. That is, when the hard part 11 in the reaction force frame part 57 reaches the elastic deformation limit, as shown by a two-dot chain line in FIG. 20, the elastomer 12 disposed in the recessed part 112 is compressed and the opposing part The surface 113 comes into direct contact. Therefore, further elastic deformation of the reaction force frame portion 57 is suppressed.

  In addition, the chair 1 according to the present embodiment has the left and right reaction force frame portions 57 provided with the recessed portions 112 at the same height on the left and right, so that the chair 1 can be balanced on the left and right. it can. In addition, the left and right back frames 51 can be tilted independently, and a plurality of recessed portions 112 of the left and right back frames 51 are provided in the vertical direction, so that the seating person can be twisted backward. Thus, the elastic deformation of the back support member upper portion 72 can be performed.

  Note that corresponding portions such as the opening end 114, the opening width 115 on the opening end side, the opening width 116 on the back side, and the side surface 117 in FIG. Omitted.

<Tenth Embodiment>
Next, a tenth embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 21, the chair 1 according to this embodiment includes a leg 2, a seat 4 supported by the leg 2, and a rear end portion of the seat 4 using an elastic deformation of a member. The backrest 5 is operatively supported, and the armrest 84 is provided between an intermediate portion of the backrest 5 and the seat 4. The armrest 84 is made of hard synthetic resin, and is curved so as to protrude toward the front upper side. One end of the armrest 84 is pivotally attached to an intermediate portion of the backrest 5 via an upper shaft 841, and the other end is pivotally attached to an intermediate portion of the seat 4 via a lower shaft 842.

  The chair 1 is configured such that the backrest 5 tilts backward with the elastic deformation of the member due to the backward load acting on the backrest 5, and the armrest 84 is also elastically deformed at that time. It is like that. That is, when the backrest 5 tilts backward with respect to the seat 4, the distance between the upper shaft 841 and the lower shaft 842 gradually increases, and the armrest 84 is elastically deformed in a direction that reduces the degree of curvature. Yes.

  The present invention is applied to the armrest 84 of the chair 1 as described above.

  As shown in FIG. 21, the armrest 84 is mainly composed of the hard portion 11. More specifically, when the armrest 84, which is a structural material that is elastically deformed by receiving a load, is integrally provided with a pair of opposing surfaces 113 with the distal end 113a open, the armrest 84 is elastically deformed. The front end 113a side of the facing surface 113 is close to the armature 84 so that the elastic deformation characteristics of the armrest 84 change. The armrest 84 includes a hard portion 11 that elastically deforms in the bending direction when a load is applied, and a pair that approaches the inside along with the elastic deformation as viewed from the bending direction of the hard portion 11. The opposing surface 113 is formed. This armrest 84 is a structural material that supports both ends, and the side on which a load is applied when seated is the inner side of elastic deformation. A concave portion 112 is provided on the upward surface 843 of the hard portion 11, that is, on the side on which the compressive stress acts when elastically deforming in a direction in which the degree of curvature decreases, in other words, on the inner surface when viewed from the bending direction. The elastomer 12 is partially disposed in the portion 112, and when the armrest 84 is elastically deformed more than a certain amount, the opposing surfaces 113 of the recessed portion 112 are in direct contact with each other to further deform the armrest 84. It comes to deter. More specifically, the hard portion 11 includes a thin portion 91 and thick portions 92 provided on both sides of the thin portion 91 and having a thickness dimension larger than that of the thin portion 91. The recessed portion 112 is formed between the meat portions 92, and the facing surface 113 is formed inside the recessed portion 112. The inner side when viewed from the bending direction in which the facing surface 113 is formed is a side on which internal stress in the compression direction increases as bending deformation progresses due to an applied load, and the bending is performed in a direction in which the radius of curvature increases. It refers to the side opposite to the center of curvature when deformed.

  With such a chair 1, when the backrest 5 tilts backward with respect to the seat 4 from the state indicated by the solid line in FIG. 21, the hard portion 11 of the armrest 84 is elastically deformed to gently receive the seated person. become. This elastic deformation is the same as that of the first embodiment, and the elastic deformation characteristics of the hard portion 11 change suddenly before and after the opposing surfaces 113 come into contact with each other. It is possible to prevent the backrest 5 from tilting further backward. That is, as shown by a two-dot chain line in FIG. 21, when the hard portion 11 in the armrest 84 reaches the elastic deformation limit, the elastomer 12 disposed in each concave portion 112 is compressed to the limit, The surface 113 comes into direct contact. Therefore, further elastic deformation of the armrest 84 is inhibited, and a deterring force also acts on the back tilting operation of the backrest 5. Therefore, in such a case, the armrest 84 serves as an auxiliary reaction force mechanism for returning the backrest 5 to the initial posture, and to prevent the backrest 5 from tilting backward too much. It will play a role as a stopper. Note that corresponding portions such as the opening end 114 and the side surface 117 in the figure are denoted by the same reference numerals as those in the above-described embodiment, and detailed description thereof is omitted.

<Eleventh embodiment>
Next, an eleventh embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 22, the chair 1 of this embodiment includes a backrest 5 in which a mesh-like tension fabric 52 is stretched between left and right back frames 51, and a lumbar is provided on the waist of the backrest 5. Support 85 is provided. The lumbar support 85 has both ends supported by the left and right back frames 51 and a holding portion 851 disposed on the front facing surface 853 side of the stretched fabric 52, and a load from a seated person disposed on the front surface of the holding portion 851. And a lumbar support body 852 made of a hard synthetic resin that is elastically deformable in the thickness direction.

  The present invention is applied to the lumbar support main body 852 of the chair 1 as described above.

  As shown in FIG. 22, the lumbar support main body 852 mainly includes the hard portion 11. More specifically, when the armrest 84 is elastically deformed by integrally providing a pair of opposing surfaces 113 with the distal end 113a open at the elastically deformed portion of the lumbar support main body 852 that is elastically deformed under load. Further, the elastic deformation characteristic of the lumbar support main body 852 changes so that the tip 113a side of the facing surface 113 comes close to the front surface 113a. The lumbar support main body 852 includes the hard portion 11 that is elastically deformed in the bending direction when a load is applied. The lumbar support main body 852 approaches the inside as seen from the bending direction of the hard portion 11 along with the elastic deformation. A pair of opposing surfaces 113 are formed. The lumbar support main body 852 is a structural material that supports both ends, and the side on which a load is applied when seated is the inner side of elastic deformation. A plurality of recessed portions 112 are provided on the forward-facing surface 853 of the hard portion 11, that is, the side on which the compressive stress acts when receiving a load and elastically deforming in the thickness direction, in other words, the inner surface when viewed from the bending direction, The elastomer 12 is partially disposed in each of the recessed portions 112, and when the lumbar support main body 852 is elastically deformed more than a certain amount, the opposing surfaces 113 of the recessed portion 112 are in direct contact with each other so that the lumbar support main body Further deformation of 852 is suppressed. More specifically, the hard portion 11 includes a thin portion 91 and thick portions 92 provided on both sides of the thin portion 91 and having a thickness dimension larger than that of the thin portion 91. The recessed portion 112 is formed between the meat portions 92, and the facing surface 113 is formed inside the recessed portion 112. The inner side when viewed from the bending direction in which the facing surface 113 is formed is a side on which internal stress in the compression direction increases as bending deformation progresses due to an applied load, and the bending is performed in a direction in which the radius of curvature decreases. It refers to the center of curvature when deformed.

  With such a chair 1, when the seated person's waist is strongly pressed against the lumbar support 85, the hard part 11 of the lumbar support body 852 is elastically deformed, and the seated person's waist is softly received. This elastic deformation is the same as that of the first embodiment, and the elastic deformation characteristics of the hard portion 11 change suddenly before and after the opposing surfaces 113 come into contact with each other. It is suppressed that the lumbar support main body 852 is further curved. That is, when the hard portion 11 in the lumbar support main body 852 reaches the elastic deformation limit, the elastomer 12 disposed in each recessed portion 112 is compressed, and the opposing surfaces 113 come into direct contact with each other. Therefore, further elastic deformation of the lumbar support main body 852 is suppressed. Therefore, with such a lumbar support 85, it is possible to keep the seated person's waist soft while maintaining a certain degree of moderation. Note that corresponding portions such as the opening end 114 in the drawing are denoted by the same reference numerals as those in the above-described embodiment, and detailed description thereof is omitted.

<Twelfth embodiment>
Next, a twelfth embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 23, the chair 1 of this embodiment is the same chair 1 as that of the eighth embodiment with a hanger 86 attached thereto, and the same or corresponding parts are denoted by the same reference numerals and described. Omitted.

  As shown in FIG. 23, the hanger 86 includes a base 861 attached to the upper end of the back support member 7, a hanger post 862 extending upward from the base 861, and a hanger supported on the upper end of the hanger post 862. The base 861, the hard part 11 of the hanger column 862, and the hanger main body 863 are integrally formed of a hard synthetic resin.

  The present invention is applied to the hanger column 862 of the chair 1 as described above.

  As shown in FIG. 23, the hanger column 862 is mainly composed of the hard portion 11. More specifically, a pair of opposing surfaces 113 with the distal end 113a open are integrally provided at the elastically deformed portion of the hanger column 862, which is a structural material that is elastically deformed under load, and the hanger column 862 is elastically deformed. At this time, the front end 113a side of the facing surface 113 is close to the hanger column 862 so that the elastic deformation characteristics of the hanger column 862 change. The hanger column 862 includes a hard portion 11 that elastically deforms in the bending direction when a load is applied, and a pair of the hanger struts 862 that approaches the inside in accordance with the elastic deformation as viewed from the bending direction of the hard portion 11. The opposing surface 113 which forms is formed. The hanger column 862 is a cantilevered structural material, and the side opposite to the side on which the load is applied when seated is the inside of the elastic deformation. A concave portion 112 is provided on the back surface 864 of the hard portion 11, and the elastomer 12 is partially disposed in the concave portion 112. When the hanger column 862 is elastically deformed more than a certain amount, the concave portion 112 is opposed to the concave portion 112. The surfaces 113 are in direct contact with each other to prevent further deformation of the hanger column 862. More specifically, the hard portion 11 includes a thin portion 91 and thick portions 92 provided on both sides of the thin portion 91 and having a thickness dimension larger than that of the thin portion 91. The recessed portion 112 is formed between the meat portions 92, and the facing surface 113 is formed inside the recessed portion 112. The inner side when viewed from the bending direction in which the facing surface 113 is formed is a side on which internal stress in the compression direction increases as bending deformation progresses due to an applied load, and the bending is performed in a direction in which the radius of curvature decreases. It refers to the center of curvature when deformed.

  With such a chair 1, the hanger support 862 can be elastically deformed rearward relatively easily, so that the operation of putting clothes on the hanger 86 and the operation of removing clothes from the hanger 86 can be easily performed. . This elastic deformation is the same as that of the first embodiment, and the elastic deformation characteristics of the hard portion 11 change suddenly before and after the opposing surfaces 113 come into contact with each other. The hanger column 862 is prevented from further bending. In addition, there is a certain limit to the deformation of the hanger column 862 during the operation, and the hanger column 862 is not deformed unnecessarily, so that unexpected external force acts on the clothes and the hanger column 862 is detached from the hanger 86. Problems can be suppressed. Note that corresponding portions such as the opening end 114 in the drawing are denoted by the same reference numerals as those in the above-described embodiment, and detailed description thereof is omitted.

<13th Embodiment>
Next, a thirteenth embodiment of the present invention will be described with reference to FIGS.

  The chair 1 of this embodiment is provided with a headrest 87 at the upper end of the backrest 5 as shown in FIG. 24 and 25, the headrest 87 includes a mounting portion 871 whose lower end is held by the backrest 5, a headrest frame 872 extending upward from the upper end of the mounting portion 871, and the headrest frame 872. And a headrest body 873 attached to the upper end of the headrest. The headrest frame 872 is mainly composed of a hard synthetic resin hard portion 11 that is elastically deformed when a backward load is applied to the headrest main body 873.

  The present invention is applied to the headrest frame 872 of the chair 1 as described above.

  As shown in FIGS. 24 and 25, the headrest frame 872 is mainly configured by the hard portion 11. More specifically, the headrest frame 872 is elastically deformed by providing a pair of opposing surfaces 113 with the distal end 113a open at the elastically deformed portion of the headrest frame 872 that is elastically deformed under load. At this time, the front end 113a side of the facing surface 113 is close to the headrest frame 872, and the elastic deformation characteristic of the headrest frame 872 is changed. A concave portion 112 is provided on the back surface 874 of the hard portion 11, that is, the side on which compressive stress acts when elastically deformed backward, in other words, the inner surface as viewed from the bending direction, and the elastomer 12 is provided in the concave portion 112. When the headrest frame 872 is elastically deformed more than a certain amount, the opposing surfaces 113 of the recessed portion 112 are in direct contact with each other so that further deformation of the headrest frame 872 is suppressed. It has become. More specifically, the hard portion 11 includes a thin portion 91 and thick portions 92 provided on both sides of the thin portion 91 and having a thickness dimension larger than that of the thin portion 91. The recessed portion 112 is formed between the meat portions 92, and the facing surface 113 is formed inside the recessed portion 112. The inner side when viewed from the bending direction in which the facing surface 113 is formed is a side on which internal stress in the compression direction increases as bending deformation progresses due to an applied load, and the bending is performed in a direction in which the radius of curvature increases. It refers to the side opposite to the center of curvature when deformed.

  With such a chair 1, when a load is applied to the headrest 87 backward, the hard portion 11 of the headrest frame 872 is elastically deformed and softly receives the seated person's head. This elastic deformation is the same as that of the first embodiment, and the elastic deformation characteristics of the hard portion 11 change suddenly before and after the opposing surfaces 113 come into contact with each other. The headrest 87 is restrained from tilting further backward. That is, when the hard portion 11 in the headrest frame 872 reaches the elastic deformation limit, the elastomer 12 disposed in the recessed portion 112 is compressed, and the opposing surfaces 113 come into direct contact with each other. Therefore, further elastic deformation of the headrest frame 872 is suppressed. Therefore, excessive deformation of the headrest frame 872 can be suppressed without the need to provide a special stopper. Note that corresponding portions such as the opening end 114 in the drawing are denoted by the same reference numerals as those in the above-described embodiment, and detailed description thereof is omitted.

<Fourteenth embodiment>
Next, a fourteenth embodiment of the present invention is described with reference to FIG.

  As shown in FIG. 26, the chair 1 of this embodiment includes a leg body 2, a seat 4 supported by the leg body 2, and a backrest 5 supported by the seat 4.

  As shown in FIG. 26, the leg body 2 includes a base 27 having a U-shape in plan view, a leg support 29 erected from both left and right ends of the base 27, and a seat extending rearward from the upper end of the leg support 29. In this embodiment, the base 27, the rigid portion 11 of the leg support 29, and the seat receiving portion 26 are integrally formed of a hard synthetic resin.

  The present invention is applied to the leg support 29 of the chair 1 as described above.

  As shown in FIG. 26, the leg support 29 is mainly composed of the hard portion 11. More specifically, a pair of opposing surfaces 113 having an open end 113a side are integrally provided at a portion of the leg support 29, which is a structural material that is elastically deformed under a load, and the reaction force frame portion 57 is elastic. When deformed, the front end 113a side of the facing surface 113 approaches and the elastic deformation characteristic of the reaction force frame portion 57 changes. The leg struts 29 have, for example, a rectangular cross section, and the back surface 291 of the hard part 11, that is, the side on which the compressive stress acts when elastically deformed rearward, in other words, the inner side as viewed from the bending direction. A concave portion 112 is provided on the surface of the concave portion 112, and the elastomer 12 is partially disposed in the concave portion 112. When the leg support 29 is elastically deformed more than a certain amount, the opposing surfaces 113 of the concave portion 112 are directly connected to each other. A further deformation of the leg strut 29 is prevented by abutting. More specifically, the hard portion 11 includes a thin portion 91 and thick portions 92 provided on both sides of the thin portion 91 and having a thickness dimension larger than that of the thin portion 91. The recessed portion 112 is formed between the meat portions 92, and the facing surface 113 is formed inside the recessed portion 112. The inner side when viewed from the bending direction in which the facing surface 113 is formed is a side on which internal stress in the compression direction increases as bending deformation progresses due to an applied load, and the bending is performed in a direction in which the radius of curvature decreases. It refers to the center of curvature when deformed.

  In the case of such a chair 1, when the seated person moves the load backward, the seat 4 sinks together with the seat receiving portion 26 while the leg support 29 is elastically deformed backward. This elastic deformation is the same as that of the first embodiment, and the elastic deformation characteristics of the hard portion 11 change suddenly before and after the opposing surfaces 113 come into contact with each other. The seat 4 is prevented from sinking further. That is, when the hard portion 11 in the leg support 29 reaches the elastic deformation limit, the elastomer 12 disposed in the recessed portion 112 is compressed, and the opposing surfaces 113 are in direct contact with each other. Therefore, further elastic deformation of the leg support 29 is suppressed. Therefore, excessive deformation of the leg 2 can be suppressed without the need to provide a special stopper. Note that corresponding portions such as the opening end 114 and the side surface 117 in the figure are denoted by the same reference numerals as those in the above-described embodiment, and detailed description thereof is omitted.

  In addition, regardless of whether or not the elastomer is filled, various shapes of the recessed portion are conceivable. In the embodiment, the back side opening width 116, compared to the opening width 115, 135 on the opening end side by expanding the back side of the recessed portions 112, 132 to both sides with respect to the opening ends 114, 134 side. A description has been given of a configuration in which 136 is set large, that is, a configuration having a T-shape in a side view, but by bending the back side of the recessed portion 112 to one side with respect to the opening end 114 side, compared to the opening width 115 on the opening end side By setting the opening width 116 on the back side to be large, that is, having an L shape in side view as shown in FIG. 27, or by bulging the back side of the recessed portion 112 to the opening end 114 side in a round shape One having a larger opening width 116 on the rear side than the opening width 115 on the opening end side, that is, one having a side keyhole shape as shown in FIG. Further, the recessed portion does not necessarily need to have a larger opening width on the back side than the opening width on the opening end side, and may be as shown in FIG. 29, FIG. 30, or FIG. Further, as shown in FIG. 32, the concave portion 112 has a curved surface on the tip 113a side, in other words, the opposing surface 113 and the outer surface on the opening end side are continuously rounded. It may be. Moreover, although not shown in figure, the recessed part may be provided with the inclined surface in the front end side. That is, the tip 113a of the facing surface 113 in the recessed portion 112 means the end of the facing surface 113 on the side that is displaced more largely than the base end of the facing surface 113 that is difficult to displace when the structural material is elastically deformed. In addition, the front end 113 a side of the facing surface 113 means the entire portion of the facing surface 113 that is closer to the tip than the base end. In other words, the front end 113a side of the facing surface 113 means the periphery of the end of the facing surface 113, and not only the most advanced point, but also the portion closer to the facing surface 113 than the most advanced point or the outer surface than the most advanced point. It is a concept that includes a close-up part. In the above examples, corresponding portions such as the facing surface 113, the thick portion 92, and the thin portion 91 are denoted by the same reference numerals as those in the above-described embodiment, and detailed description thereof is omitted.

  Further, in the embodiment described above, the case where no elastomer is disposed in the recessed portion and the case where the elastomer is filled in a part of the recessed portion has been described, but the elastomer may be disposed in the entire recessed portion. Of course. As an example, as shown in FIG. 33, the outer surface 111 of the hard portion 11 and the outer surface 121 of the elastomer 12 are configured to be flush with each other. Since the elastomer 12 having the same shape as that of the recessed portion 112 is disposed, the appearance that the structural material is integrated by the hard portion 11 and the elastomer 12 that is the soft portion is obtained. Therefore, the appearance as furniture can be improved. Further, in such a case, when the hard part 11 is deformed to a predetermined elastic deformation limit, the opposing surfaces 113 come into contact with each other via the elastomer 12 to suppress elastic deformation of the hard part 11 beyond a certain level. become. Even when the elastomer is disposed on a part of the recessed portion, the elastomer is disposed only on the opening end side of the recessed portion in addition to the elastomer disposed on the back side of the recessed portion as shown in the embodiment. The thing etc. which were done may be sufficient. That is, when the elastomer is disposed on a part of the recessed portion, when the hard portion is deformed to a predetermined elastic deformation limit, the opposing surfaces directly contact each other and indirectly contact via the elastomer There is.

  In the embodiment described above, the ratio of the thickness dimension between the thick part and the thin part may be set as appropriate according to the required elastic deformation characteristics.

  Further, the thick portion is not limited to one having a thickness dimension larger than that of the thin portion, and may be set to be the same or smaller than the thin portion. For example, the thin portion suppresses elastic deformation. A rib may be provided. As a specific example, as shown in FIGS. 34 and 35, a pair of plate-like hard portions 11 that elastically deform under a load are provided, and a tip 113a side is opened at a portion of the hard portion 11 that is elastically deformed. And a pair of opposed walls 113b provided with the opposed surfaces 113 forming a protruding shape. The surface of the facing wall 113b on the side where the facing surface 113 is not formed is connected to a rib 118 formed integrally with the hard portion 11, and deformation other than the direction in which the tip 113a side of the facing surface 113 is close to the other is performed. It is regulated. The shape of the facing wall 113b that forms the facing surface 113 may be any shape other than that shown in FIG.

  In addition, the elastomer, which is a resin having rubber elasticity, placed in the recessed portion, is arranged with a gap so that it does not contact between the opposing surfaces in the initial state in the recessed portion, or contacts both opposing surfaces from the beginning. Various forms can be taken, such as arranging so as to fill or filling the recessed portion. And what kind of thing may be sufficient also about the shape of the elastomer distribute | arranged in a recessed part. As a specific example, as shown in FIG. 37, the shape of the elastomer 12 substantially coincides with the shape of the recessed portion 112, in other words, the elastomer 12 is disposed on the entire recessed portion 112, or as shown in FIG. As shown in FIG. 39, the recessed portion 112 is provided with the elastomer 12 over the entire opening width on the opening end 114 side and a gap between the opposing surface 113 and the elastomer 12 on the back side. In addition, a gap may be provided between the facing surface 113 and the elastomer 12 over the entire depth dimension of the recessed portion 112.

  Furthermore, in the above-described embodiment, the recessed portion is provided on the surface that receives the compressive stress. However, the recessed portion may be provided on the surface that receives the tensile stress due to elastic deformation of the hard portion. More specifically, in the embodiment, the structural material includes a hard portion that elastically deforms in the bending direction when a load is applied, and the elastic material is inwardly viewed from the bending direction of the hard portion. A pair of opposing surfaces that approach each other with deformation was formed, but the structural material had a hard part that elastically deformed in the bending direction when a load was applied. A pair of opposing surfaces may be formed on the outer side as viewed from the direction, which form a pair that approaches the elastic deformation. The outer side when viewed from the bending direction is the side where the internal stress in the tensile direction increases as the bending deformation progresses as a load is applied, and the center of curvature in the case of bending deformation in the direction of decreasing the radius of curvature. And the opposite side. As a specific example, as shown in FIG. 40 and FIG. 41, a concave portion 112 is formed which is indented into a S-shape or the like in a side view, on the side subjected to tensile stress, that is, on the outer side as viewed from the bending direction. When the hard portion 11 is deformed to a predetermined elastic deformation limit, the distal end sides of the opposing surfaces 113 forming a pair formed in the recessed portion 112 are close to each other so that the elastic deformation characteristics of the structural material change. Good. In this case, an elastomer may be disposed on a part or all of the recessed portion. 40 and 41 include the rib 118, but may not include the rib as shown in FIG.

  In addition, various changes may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Chair 11, 13 ... Hard part 112, 132 ... Recessed part 113, 133 ... Opposite surface 113a, 133a ... Tip 12, 14 ... Elastomer 91, 93 ... Thin part 92, 94 ... Thick part

Claims (8)

Provided with a structural material that is elastically deformed in response to a load, a pair of opposed surfaces having a distal end opened at the elastically deformed portion of the structural material are integrally provided, and the distal end of the opposed surface when the structural material is elastically deformed A chair that is configured so that the elastic deformation characteristics of the structural material change when the sides are close to each other.   The structural material is provided with a hard part that elastically deforms when a load is applied, and a pair of opposing surfaces are formed on the inner side as viewed from the bending direction of the hard part, along with the elastic deformation. The chair according to claim 1.   The structural material is provided with a hard portion that elastically deforms when a load is applied, and a pair of opposing surfaces that form a pair approaching the elastic deformation are formed on the outside as viewed from the bending direction of the hard portion. The chair according to claim 1.   The chair according to claim 2 or 3, wherein the structural material is an elastic deformation on the side opposite to the side on which the load is applied when seated.   The chair according to claim 2 or 3, wherein the structural material is such that a side on which a load is applied when sitting is an inner side of elastic deformation.   The chair according to claim 1, 2, 3, 4 or 5, wherein the opposing surfaces are brought into direct contact with each other when the structural material is elastically deformed more than a certain amount.   7. The structural material according to claim 1, 2, 3, 4, 5 or 6, wherein the structural material includes a recessed portion that forms the facing surface, and an elastomer is disposed on all or a part of the recessed portion. Chair.   The hard part is provided with a thin part and a thick part having a thickness dimension larger than that of the thin part provided on both sides of the thin part, and a recessed part is formed between the thick parts. The chair according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the facing surface is formed inside the recessed portion.

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