JP2017086696A - Chair link member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rigid chair link member which is a resin molding.SOLUTION: A chair link member is configured to provide at least two pairs which rotate mutually around an axis, between two mating side members, and provide a link mechanism between the mating side members. A link member 62 is a synthetic resin molding formed of two members, namely an A component 63 and a B component 64, in which at least two axis parts 65 forming the plural pairs and reception parts 66 for receiving the axis parts 65 are integrated with any one of the A component 63 and the B component 64, and a connection part 67 for coupling the A component 63 and the B component 64 between two axis parts 66 (and being integrated with any one of the A component and B component) is provided. The A component 63 and B component 64 are made to face so as to sandwich bearing parts 57e, 58e of the mating side members forming the pair, then, the axis parts 65 and the reception parts 66 for receiving the axis parts are fitted, and then the connection part 67 fastens the A component 63 and B component 64 for integrating them.SELECTED DRAWING: Figure 23

Description

  The present invention relates to a link member of a chair.

  2. Description of the Related Art Conventionally, there are those that use a link mechanism to freely rotate chair parts. For example, as a typical example, there is a link mechanism arranged under a seat connecting a seat and a main frame (Patent Document 1). The link mechanism is disposed between the rotation shaft member on the main frame side, the rotation shaft member on the seat side, the collar disposed between the rotation shaft member and the main frame, and between the seat and the rotation shaft member. And left and right link members.

JP, 2014-121479, A

  However, since an iron shaft is fitted between the mating member to form the link pair, if the link material is made of iron, the slidability becomes extremely bad, and it becomes impossible to rotate or abnormal noise. There is a problem that occurs. For this reason, a collar for improving slidability is required.

  For this reason, in the conventional link member, the number of parts will increase. Moreover, since the number of parts increases, manufacturing man-hours and management man-hours also increase. In manufacturing man-hours, it takes man-hours (manual time) such as attaching the collar after passing through the rotation shaft member from the left-right direction and then attaching the link member, and work from the left-right direction is also required.

  On the other hand, if a resin shaft is used, the slidability is improved, but the strength is inferior to that of iron. Moreover, if it is cantilevered, there is a problem that it is easy to break.

  It is an object of the present invention to provide a link member for a chair that has a small number of parts and further reduces the number of manufactured parts (assembly man-hours) and management man-hours (management effort). In other words, the object is to provide a strong chair link member that is a resin molded product.

  In order to achieve such an object, the invention according to claim 1 is characterized in that at least two pairs that rotate about an axis are formed between two opposing members, and a link mechanism is provided between the opposing members. In the link member of the chair to be configured, the link member is a synthetic resin molded product composed of two parts of an A part and a B part, and at least two shaft parts constituting a plurality of pairs and a part receiving the shaft part are A It is formed integrally with either the component or the B component, and has a connecting portion that is formed integrally with either the A component or the B component and connects the A component and the B component. The A part and the B part face each other so as to sandwich the bearing part of the mating member to be configured, and the shaft part and the part that receives the shaft part are fitted together, and then the A part and the B part are fastened together at the connecting part. It is supposed to be a structure.

  According to a second aspect of the present invention, in the chair link member according to the first aspect, the A part has one of the shaft part and the part that receives the shaft part by integral molding, and the B part has the shaft part and the shaft. One of the parts receiving the part is formed by integral molding.

  The invention according to claim 3 is characterized in that, in the link member of the chair according to claim 1 or 2, the connecting portion protrudes from at least one member between the two shaft portions.

  According to a fourth aspect of the present invention, in the link member of the chair according to the first or second aspect, the shaft portion itself serves as the connecting portion.

  According to a fifth aspect of the present invention, in the chair link member according to any one of the first to fourth aspects, the component having the shaft portion of the A component or the B component is formed of a material having good sliding property. It is characterized by being.

  According to a sixth aspect of the present invention, in the chair link member according to any one of the first to fifth aspects, the operation portion is integrally formed with at least one of the A part and the B part. It is characterized by that.

  The invention according to claim 7 is the chair link member according to any one of claims 1 to 6, wherein at least a flexible back frame constituting a backrest surface and a rigid back frame are provided. In a backrest connected at one end, a link member is arranged between the back frame and the back frame to form a link mechanism, and the form of the back frame is changed by swinging the link member over the thought point. It is characterized by.

  Further, the invention according to claim 8 is characterized in that in the chair link member according to any one of claims 1 to 7, the chair has a contact portion for restricting the movement of the link mechanism with the counterpart member. Features.

  According to the link member of the chair according to claim 1, since the link member is made of resin, is made into two members, and is fitted and integrated, and the shaft portion is a double-supported structure, it is made of only a resin molded product. Although it is a member that is structurally strong, it is structurally inferior in strength. Further, since the shaft portion is made of resin integrally molded with the A component or the B component, the movement is smooth and no abnormal noise is generated. In addition, since there are no iron connecting pins or shafts that make up the kinematic pair, there is no need to use resin collars or bushes to ensure the generation of abnormal noise and ease of movement, reducing the number of parts. Assembling effort, man-hours, and management man-hours can also be reduced, and component costs and manufacturing costs can be reduced.

  In addition, it is possible to construct a single element that incorporates two shaft parts by abutting two parts of the A part and the B part, so that the shaft part is not exposed to the appearance, so that it looks good as a chair. Also gets better.

  Moreover, according to the link member of the chair according to claim 2, since the shaft part is provided in one part and the part that receives the shaft part is provided in the other part, the two members that connect one part to each other are provided. Since the other part is fitted in a state in which the positional relationship between the two mating members constituting the link mechanism is fixed to the bearing bracket portion through the shaft portion, positioning is easy and assembly is easy. Greatly improved. Further, at least only the part for integrally forming the shaft portion may be formed from a material having a high slidability, and the other part may not necessarily be a material having a high slidability, and the mold structure can be simplified.

  Moreover, according to the link member of the chair of Claim 3, since the connection part protrudes from at least one member between two axial parts, it is easy to improve the rigidity as a link member.

  Further, according to the link member of the chair according to claim 4, since the shaft portion itself also serves as the connecting portion, in response to a request for shortening the distance between the shaft portions or taking a wide space around the shaft portion. Can also respond.

  Moreover, according to the link member of the chair according to claim 5, since the component having the shaft portion among the A component and the B component is made of a material having good slidability, the slidability of the shaft portion is further improved. Therefore, a collar for improving the slidability is not required.

  Further, according to the link member of the chair according to claim 6, since the operation portion is integrally formed with the link member, there is no need to reattach the operation lever, and the assembly work can be omitted and the integrally formed product As a result, the appearance is well organized and smart. In addition, since an operation wire or the like is not required, it is inexpensive and can be reduced in size and weight.

  According to the link member of the chair according to claim 7, the link member is arranged between the flexible back frame constituting the backrest surface and the rigid back frame to constitute the link mechanism, and the link Since the shape of the back frame is changed by swinging the member over the thought point, the shape of the back frame can be changed by a simple operation of changing the connecting position by swinging the link member. .

  Furthermore, according to the link member of the chair according to claim 8, since the stopper portion is provided, the movable range can be determined in advance. Also, it will not move too much.

It is a front perspective view which shows the external appearance of the chair to which the link member of the chair of this invention is applied. It is a right view of the chair. It is a rear view of the chair. It is a right view which shows the structure of the part relevant to the leg base of the chair. It is a partially exploded right side perspective view which shows the structure of the part relevant to the leg base of the chair. It is a right side longitudinal cross-sectional view which shows the structure of the pedestal support cylinder part of the leg base of the chair. It is a right side longitudinal cross-sectional view which shows typically the structure of the pedestal support cylinder part of the leg base of the chair. It is a right side longitudinal cross-sectional view which shows typically the other example of the structure of the pedestal support cylinder part of a leg base. It is a right side longitudinal cross-sectional view which shows still another example of the structure of the pedestal support cylinder part of a leg base typically. It is a longitudinal cross-sectional view of the direction orthogonal to the longitudinal direction which shows an example of embodiment of the structure of the leg blade of a leg base. It is a longitudinal cross-sectional view of the direction orthogonal to the longitudinal direction which shows the other example of the structure of the leg blade | wing of a leg base. It is a side view which shows the backrest of the synchro-rocking mechanism to which the link member of the chair concerning this invention is applied, the relationship between a seat outer shell, and a main frame. It is the bottom view. It is the perspective view which looked at the inner shell of the seat of the synchro-rocking mechanism from the top. It is the perspective view which looked at the outer shell of the seat of the synchro-rocking mechanism from the top. It is the perspective view seen from diagonally downward front which shows the relationship between a main frame, reaction force provision mechanism, and a front link. It is the perspective view seen from the slanting back of the main frame. It is a perspective view of a synchro frame. It is a perspective view which shows an example of embodiment of a locking mechanism. It is the perspective view which looked at the seat outer shell from the bottom. It is a perspective view which shows a back frame and the link member attached to this. It is a perspective view shown in the state where one embodiment of a back frame and a back frame was separated. It is a perspective view which shows 1st embodiment of a link member in an assembly state. It is the perspective view which decomposed | disassembled the link member and looked at the B component side from the A component side. It is the perspective view which decomposed | disassembled the link member and looked at the A component side from the B component side. It is a perspective view which shows the link member with a lever which is 2nd embodiment of a link member in an assembly state. It is the perspective view which decomposed | disassembled the link member and looked at the B component side from the A component side. It is the perspective view which decomposed | disassembled the link member into the A component side and the B component side, and looked at the A component side from the B component side. It is a perspective view of a lever ring. It is a figure which expands and shows the lower side part of a back frame. It is a disassembled perspective view of a grooved plate. It is a perspective view of a lumbar plate. It is sectional drawing which shows the connection state of a back frame, a grooved plate, and a lumbar plate.

  Hereinafter, the configuration of the present invention will be described in detail based on embodiments shown in the drawings. In the description of the present invention, “upper” and “lower”, “front” and “rear”, and “left” and “right” are defined based on the seated person sitting on the chair (in other words, And “up” and “down”, “front” and “rear”, and “left” and “right” as viewed from the seated person).

  1 to 3 show an outline of an embodiment of a chair to which the present invention is applied. The chair of this embodiment includes a leg 1, a main frame 5 supported by the leg 1, a synchro frame 8 to which a backrest 9 is attached, and a seat receiving member (a seat frame or a seat to which a seat 7 is attached. (Referred to as an outer shell) 6, and the seat 7 and the backrest 9 are synchronously mounted on the main frame 5 with the sync frame 8 and the front link 30 interposed therebetween.

  The leg body 1 of the chair of the present embodiment includes a leg feather type leg base 2 and a pedestal 3 standing upright at the center of the leg base 2.

  Moreover, the leg base 2 of this embodiment has the base 10 and the several leg blade | wing 20 integrally shape | molded by resin.

  In addition, as resin as a raw material of the leg base 2, specifically, for example, as an example, nylon with glass fiber may be used.

  A pedestal 3 that supports the seat is fitted and attached to the base 10.

  Specifically, the base 10 is provided with a vertical through hole 11 having a circular cross section (in other words, in plan view), and the leg 3 is fitted and fixed to the through hole 11.

  In this embodiment, the pedestal 3 is constituted by a gas spring having a cylinder 18 and a rod 19 that can be moved up and down with respect to the cylinder 18, and the cylinder 18 is fitted into the through hole 11 provided in the base 10. By fixing, the pedestal 3 (that is, gas spring) is fixed to the leg base 2.

  Here, among the structures related to the base 10 and the through hole 11, the upper end side portion 11 a and the lower end side portion 11 b of the through hole 11 have convenience in molding the leg base 2 and assembling the leg body 1. It is considered and provided, and is not a structure related to the present invention, and thus is not an essential configuration for the present invention. The upper end portion 11a and the lower end portion 11b are formed with larger diameters in the cross section (plan view) than the portion between them, and the inner circumferences of the upper end portion 11a and the lower end portion 11b. The surface does not come into contact with the outer peripheral surface of the pedestal 3 in a state where the pedestal 3 is fitted and fixed in the through hole 11, and does not contribute to the fixation of the pedestal 3.

  That is, the target portion in the examples shown in FIGS. 6 and 7 is a portion between the upper end side portion 11a and the lower end side portion 11b in the through hole 11, and specifically, the range indicated by reference numeral 12 is configured. This is the structure of the inner peripheral surface (in other words, the inner wall) of the peripheral wall.

  Hereinafter, the range indicated by reference numeral 12 in the base 10 of the leg base 2 is the inner wall of the range indicated by reference numeral 12, that is, between the upper end side portion 11 a and the lower end side portion 11 b of the through hole 11. The inner wall constituting this part is referred to as a “leg pillar supporting cylinder 12”.

  And in this embodiment, the inner peripheral surface (in other words, the inner wall which comprises the through-hole 11 of the base 10) of the pedestal support cylinder part 12 contacts the outer peripheral surface of the pedestal 3 over the whole periphery. A pair of contact portions 12A and 12B and a non-contact portion 12C that does not contact the outer peripheral surface of the pedestal 3 between the pair of upper and lower contact portions 12A and 12B are configured.

  The pair of upper and lower contact portions 12A and 12B constituting the inner peripheral surface (inner wall constituting the through-hole 11) of the pedestal support cylinder portion 12 has an inner diameter in the cross section that gradually decreases from the upper side to the lower side. It is formed into a tapered shape.

  Accordingly, the pair of upper and lower contact portions 12A and 12B are inclined surfaces that gradually approach toward the center position (that is, the axial center position) in plan view of the through-hole 11 as it goes downward, in other words, downward It is formed as an inclined surface so that it can receive and support the load.

  That is, in the present embodiment, the pair of upper and lower contact portions 12A and 12B are both formed in a tapered shape in which the inner diameter in the cross section decreases as going downward. In other words, each of the pair of upper and lower contact portions 12A and 12B is formed as an annular tapered portion having an inclination that gradually decreases in diameter toward the lower side.

  On the other hand, the cylinder 18 of the gas spring constituting the pedestal 3 in the present embodiment has an upper cylindrical portion 18A having a constant outer diameter in the cross section (that is, a constant thickness) and an outer diameter in the cross section. The lower cylindrical portion 18B, which has a constant diameter smaller than the outer diameter of the upper cylindrical portion 18A, and the upper end of the outer peripheral surface are connected continuously to the lower end of the outer peripheral surface of the upper cylindrical portion 18A without any step, and the lower end of the outer peripheral surface is lower. The upper end of the outer peripheral surface of the cylindrical part 18B and an intermediate inclined part 18C that are connected continuously without a step are provided.

  That is, in the present embodiment, the intermediate inclined portion 18C has a tapered shape in which the outer diameter in the cross section gradually decreases as it goes from the upper side to the lower side, that is, a tapered shape in which the outer diameter decreases as it goes downward. To be formed.

  And when the gas spring (cylinder 18, rod 19) which comprises the pedestal 3 is inserted from the upper part into the through-hole 11 provided in the base 10 of the leg base 2, the intermediate | middle inclination part 18C of the cylinders 18 is formed. The pedestal column support cylinder portion 12 is fitted and fixed.

  At this time, a pair of upper and lower contact portions 12A and 12B of the inner peripheral surface of the pedestal support cylindrical portion 12 is in contact with an outer peripheral surface of the intermediate inclined portion 18C, and the cylinder 18 is received by the pair of upper and lower contact portions 12A and 12B. Supported.

  Specifically, the pair of upper and lower contact portions 12A and 12B is a tapered surface whose inner diameter in the cross section decreases as it goes downward, and the intermediate inclined portion 18C of the cylinder 18 crosses the cross section as it goes downward. The outer surface of the cylinder 18 is tapered so that when the gas spring as the pedestal 3 is inserted into the through hole 11 from above, the intermediate inclined portion 18C of the cylinder 18 is inclined so as to support it. A downward load applied to the outer peripheral surface of the intermediate inclined portion 18C of the cylinder 18 is contacted with the pair of contact portions 12A and 12B (in other words, surface contact), and the outer peripheral direction is caused by the inner peripheral surfaces of the pair of upper and lower contact portions 12A and 12B. It is supported and supported by.

  As a result, the gas spring as the pedestal 3 is fitted into the through hole 11 and fixed to the pedestal support cylindrical portion 12, and then fixed to the leg base 2.

  FIG. 7 shows the structure of the inner peripheral surface (in other words, the inner wall constituting the through hole 11) of the pedestal support cylinder 12 in the example shown in FIG. 6 in terms of the upper contact portion 12A, the lower contact portion 12B, and the non-contact. In order to make it easy to understand the mutual relationship between the shapes of the portions 12C, they are schematically represented by emphasizing the aspect of inclination.

  In FIG. 7, the slope of the upper contact portion 12 </ b> A gradually approaching toward the center position (that is, the axial center position) in plan view of the through hole 11 toward the lower side with respect to the reference line V in the vertical direction. The inclination angle is θ1. The tilt angle is defined as a counterclockwise rotation angle from the vertical reference line V.

  Further, as the lower contact portion 12B, the inclination angle with respect to the reference line V in the vertical direction of the inclined surface gradually approaching toward the center position (axial center position) in plan view of the through hole 11 as it goes downward. θ1.

  The inclination angle θ1 of the slope as the upper contact portion 12A and the slope as the lower contact portion 12B with respect to the reference line V in the vertical direction is not limited to a specific size, and the outer peripheral surface of the pedestal 3 The load is adjusted to an appropriate size in consideration of the inclination angle required to receive and support the downward load applied to the head from the outer peripheral direction by the inner peripheral surfaces of the pair of upper and lower contact portions 12A, 12B. The

  Further, the upper contact portion 12A and the lower contact portion 12B are formed to be adjusted to each other so that the extending direction of the inclined surface as the upper contact portion 12A and the extending direction of the inclined surface as the lower contact portion 12B coincide with each other. The In FIG. 7, specifically, the extending direction of the slope as the upper contact portion 12A and the extending direction of the slope as the lower contact portion 12B both coincide with the virtual straight line F.

  The virtual straight line F coincides with the position and shape of the outer peripheral surface of the pedestal 3 fitted in the through hole 11 (specifically, the tapered surface of the intermediate inclined portion 18C of the cylinder 18 of the gas spring). To do.

  That is, both of the slopes (specifically, tapered surfaces whose inner diameter decreases toward the lower side) as the pair of upper and lower contact portions 12A, 12B are both outer peripheral surfaces (specifically, It is formed so as to coincide with an imaginary straight line F representing a taper surface whose outer diameter decreases as it goes downward, whereby the outer peripheral surface of the pedestal 3 (intermediate inclined portion 18C of the cylinder 18) It comes into contact (surface contact) with a pair of upper and lower contact portions 12A, 12B that are inclined to receive and support.

  On the other hand, the non-contact portion 12C represents the extension direction of the slope as the pair of upper and lower contact portions 12A, 12B, and coincides with the virtual straight line F that coincides with the position and shape of the outer peripheral surface of the pedestal 3 or more than the virtual straight line F. It is formed so as not to protrude to the axial center position side of the through hole 11, in other words, so as to be recessed from the virtual straight line F, and thus not to contact the outer peripheral surface of the pedestal 3.

  In the present embodiment, specifically, the non-contact portion 12C is also tapered like the upper contact portion 12A and the lower contact portion 12B. The inner diameter in the cross section gradually decreases from the upper side to the lower side. Formed as a slope.

  When the inclination angle of the slope as the non-contact portion 12C with respect to the vertical reference line V is θ2, the slope as the upper contact portion 12A and the slope as the lower contact portion 12B with respect to the vertical reference line V The relationship with the inclination angle θ1 is adjusted so as to satisfy θ2 <θ1 so that the non-contact portion 12C is recessed from the imaginary straight line F and does not contact the outer peripheral surface of the pedestal 3.

  Note that the inclination angle θ2 of the inclined surface as the non-contact portion 12C with respect to the vertical reference line V is not limited to a specific size, and may be appropriately adjusted in a range satisfying 0 ≦ θ2 <θ1. preferable. Here, θ2 = 0 is a state where the surface as the non-contact portion 12C (that is, the inner peripheral surface of the non-contact portion 12C portion of the through hole 11) is a vertical surface.

  Here, the inclination angle θ1 with respect to the vertical reference line V of the inclined surface as the pair of upper and lower contact portions 12A and 12B and the inclination angle θ2 with respect to the vertical reference line V of the inclined surface as the non-contact portion 12C are given as examples only. And 2.5 ° ≦ θ1 ≦ 3.5 °, 1.0 ° ≦ θ2 ≦ 2.0 °, and more specifically, θ1 = 3.0 °, θ2 = 1.5 °. It can be considered.

  By setting the inclination angle θ1 of the pair of upper and lower contact portions 12A and 12B and the inclination angle θ2 of the non-contact portion 12C to the above-described ranges and values, the outer peripheral direction of the inner peripheral surface of the pair of upper and lower contact portions 12A and 12B The lower end of the upper contact portion 12A and the upper end of the non-contact portion 12C are connected to each other to form a continuous surface, and the non-contact portion 12C is the pedestal 3 It is comprised so that it may not contact with the outer peripheral surface.

  In the example shown in FIG. 6 and FIG. 7, in addition, the upper contact portion 12A and the non-contact portion 12C are formed as an inclined surface that is continuous without a step, although the lower end and the upper end thereof are connected and the inclination angle changes. The non-contact portion 12C and the lower contact portion 12B are formed as surfaces having a step d2 between the lower end and the upper end.

  And by being comprised like the example shown in FIG.6 and FIG.7, while being able to shape | mold the upper end side part 11a and the pedestal support cylinder part 12 of the through-hole 11 by the cutting die from upper direction. The lower end portion 11b can be molded by a punching die from below. Therefore, it is preferable in that the resin leg base 2 can be easily formed.

  However, the inclination angle θ2 of the slope as the non-contact portion 12C with respect to the reference line V in the vertical direction may be θ2 <0 in some cases. Here, θ2 <0 is gradually inclined toward the outer periphery of the pedestal column supporting cylinder portion 12 from the vertical reference line V as it goes downward, that is, as it goes downward. This is a state in which the inner diameter in the cross section gradually increases.

  Moreover, the aspect of the non-contact part 12C should just be dented rather than the virtual straight line F showing the extension direction of the slope as the upper contact part 12A and the lower contact part 12B. It is not limited to the aspect in the example shown.

  Specifically, for example, as shown in FIG. 8A, the upper contact portion 12A and the non-contact portion 12C are formed as a surface having a step d1 between the lower end and the upper end, and the non-contact portion 12C and the lower side The contact portion 12B may be formed as an inclined surface that is continuous without a step although the lower end and the upper end thereof are connected to each other and the inclination angle changes.

  Further, as shown in FIG. 8B, the upper contact portion 12A and the non-contact portion 12C are formed as a surface having a step d1 between the lower end and the upper end of each, and the non-contact portion 12C and the lower contact portion. 12B may be formed as a surface having a step d2 between the lower end and the upper end.

  According to the leg base of the chair having the pedestal support cylindrical portion 12 having the above-described configuration and the chair having the leg base, the pedestal is between the pair of upper and lower contact portions 12A and 12B that are in contact with the outer peripheral surface of the pedestal 3. 3 has a non-contact portion 12C that does not come into contact with the outer peripheral surface, so that the non-contact portion 12C is subject to undulations and distortions of the inner peripheral surface of the pedestal support cylindrical portion 12 and variations in the diameters of the parts constituting the pedestal 3. As a result, the pair of upper and lower contact portions 12A and 12B can be reliably brought into close contact with the outer peripheral surface of the cylinder 18 of the gas spring as the pedestal 3, so that the chair pedestal 3 and the resin leg base 2 It is possible to prevent rattling in the through hole 11 of the base 10 that is the mounting portion. For this reason, it is not necessary to correct the variation between individuals generated in molding, and therefore, it is not necessary to correct in the manufacturing process, and it is possible to reduce the labor involved in manufacturing.

  In the above-described embodiment, both the upper contact portion 12A and the lower contact portion 12B are formed as an annular taper portion, and are continuously formed over the entire circumference without a break in the circumferential direction. However, the configuration aspect of the upper contact portion 12A and the lower contact portion 12B is not limited to the aspect in the above-described embodiment, and the upper contact portion 12A and the lower contact portion 12B are in a direction orthogonal to the circumferential direction ( That is, a cut line in the vertical direction) or in an oblique direction (that is, a direction other than the vertical direction) may be provided.

  In the above-described embodiment, both the upper contact portion 12A and the lower contact portion 12B gradually approach the center position (that is, the axial center position) in the plan view of the through hole 11 as it goes downward. The upper contact portion 12A and the lower contact portion 12B are not limited to the form in the above-described embodiment, and the upper contact portion 12A and the lower contact portion 12B Either one or both of them may be formed as a vertical plane.

  Moreover, the structure of the pedestal support cylinder in the above-described embodiment can be widely applied to various leg bases, and the configuration of the leg base is the specific structure of the leg base 2 in the above-described embodiment. It is not limited, and moreover, it is not limited to a leg blade type leg base. For example, as a whole including the pedestal support cylindrical portion 12 as an integrated body at the center position, it is a disc shape or a cone shape or a mountain shape. It can also be applied to other leg bases.

  In addition, the structure of the pedestal support cylindrical portion in the above-described embodiment can be widely applied to various pedestals, and the configuration of the pedestal is the specific structure of the pedestal 3 in the above-described embodiment. The present invention is not limited, and moreover, it is not limited to a gas spring. For example, the present invention can be applied to a pedestal composed of a simple rod-shaped member having no lifting function.

  On the other hand, each of the plurality of leg blades 20 is disposed such that the base end portion 20a is connected to the base portion 10 and the longitudinal direction is along the radial direction centered on the base portion 10.

  In the present embodiment, five leg blades 20 are arranged radially, and the casters 4 are provided on the lower surface of each tip 20b.

  In the present embodiment, the base end portion 20a side of the leg blade 20 is not grounded, but is grounded via the caster 4 on the lower surface side at the distal end portion 20b. It should be noted that the provision of the caster 4 at the tip 20b of the leg blade 20 is not essential, and for example, a spacer or a cushion material may be provided, or the tip 20b of the leg blade 20 is convex. Alternatively, it may be directly grounded after being formed. That is, the base end portion 20a side of the leg blade 20 is not directly or indirectly grounded, and the distal end portion 20b side is directly or indirectly grounded.

  The leg blade 20 has a pair of side plates 21 and 21 provided to extend in the longitudinal direction and face each other, and a top portion 22 provided so as to connect the upper ends of the side plates 21 and 21.

  That is, the leg blade 20 is formed to have a mountain-shaped structure that opens downward in a longitudinal sectional view orthogonal to the longitudinal direction.

  In other words, the leg blade 20 is formed as having a hollow portion that is surrounded by a pair of side plates 21 and 21 and a top portion 22 that are provided to face each other and that opens downward.

  The side plate 21 of the leg blade 20 is configured such that the lower portion 21B is thicker than the upper portion 21A.

  Specifically, in the present embodiment, the thickness dimension of the side plate 21 of the leg blade 20 is configured such that the thickness dimension of the lower portion 21B is larger than the thickness dimension of the upper portion 21A.

  In the present embodiment, as shown in FIG. 9, the thickness of the upper portion 21A of the side plate 21 is constant at t1, and the thickness of the lower portion 21B of the side plate 21 is equal to that of the upper portion 21A. It is configured to be larger than the thickness dimension t1.

  In this embodiment, as shown in FIG. 9, the lower portion 21B of the side plate 21 is a portion where the thickness dimension gradually increases from the connecting portion with the upper portion 21A toward the lower side, specifically, , And a portion from the upper end of the lower portion 21B (that is, the connecting portion with the lower end of the upper portion 21A) to the position of the dimension line of the maximum thickness t2.

  However, the thickness dimensions of the upper portion 21A and the lower portion 21B of the side plate 21 may be constant or may vary as shown in FIG.

Therefore, the following i to iii are mentioned as the relationship between the thickness of the upper portion 21A and the thickness of the lower portion 21B of the side plate 21.
i) The maximum value of the thickness dimension of the lower portion 21B (t2 in the example shown in FIG. 9) is larger than the maximum value of the thickness dimension of the upper portion 21A (t1 in the example shown in FIG. 9). (Note that the relationship between the minimum value of the thickness dimension of the lower portion 21B and the minimum value of the thickness dimension of the upper portion 21A (t1 in the example shown in FIG. 9) does not matter.)
ii) The minimum value of the thickness dimension of the lower part 21B is not less than the minimum value of the thickness dimension of the upper part 21A (t1 in the example shown in FIG. 9), and the maximum value of the thickness dimension of the lower part 21B (FIG. 9). In the example shown, t2) is larger than the maximum thickness dimension of the upper portion 21A (t1 in the example shown in FIG. 9).
iii) The minimum value of the thickness dimension of the lower part 21B is not less than the maximum value of the thickness dimension of the upper part 21A (t1 in the example shown in FIG. 9), and the maximum value of the thickness dimension of the lower part 21B (FIG. 9). In the example shown, t2) is larger than the maximum thickness dimension of the upper portion 21A (t1 in the example shown in FIG. 9).

  Here, when a load is applied to the leg base 2 by sitting, the load is appropriately applied to the entire longitudinal section in the direction orthogonal to the longitudinal direction of the leg blade 20 in view of avoiding local stress concentration in the leg blade 20. From the viewpoint of sharing, the above-mentioned iii is preferable as the relationship between the thickness of the upper portion 21A of the side plate 21 and the thickness of the lower portion 21B.

  In other words, the above iii is, in any part of the lower part 21B, the thickness of the lower part 21B is equal to or greater than the maximum value of the thickness of the upper part 21A (t1 in the example shown in FIG. 9), and In at least part of the side portion 21B, the thickness of the lower portion 21B is longer than the maximum value of the thickness of the upper portion 21A (t1 in the example shown in FIG. 9).

  Here, the thickness dimension of the upper part 21A and the thickness dimension of the lower part 21B are not limited to specific values, and when the load is applied to the leg base 2 by sitting, In consideration of avoiding stress concentration, ensuring the design strength required for the leg blades, and appropriately sharing the load in the entire longitudinal section in the direction perpendicular to the longitudinal direction of the leg blades 20 Is set appropriately to an appropriate value.

  Specifically, for example, as an example only, the maximum value of the thickness dimension of the upper portion 21A (t1 in the example shown in FIG. 9) is about 4.0 to 5.5 mm, and the thickness of the lower portion 21B. It is conceivable that the maximum dimension value (t2 in the example shown in FIG. 9) is set to be about 6.5 to 8.0 mm. At this time, it is conceivable that the thickness dimension (t3 in the example shown in FIG. 9) of the lower end of the lower portion 21B is set to be about 4.5 to 6.0 mm.

  In order to satisfactorily achieve all of avoidance of stress concentration, ensuring design strength, and appropriate sharing of load, the thickness dimension t1 of the upper portion 21A is 4.5 mm as a longitudinal sectional configuration shown in FIG. And the maximum thickness t2 of the lower portion 21B is preferably set to 7.0 to 7.6 mm (in addition, the thickness t3 of the lower end of the lower portion 21B is 5.0). To 5.7 mm), and more preferably t1 = 4.5 mm and t2 = 7.6 mm (in addition, t3 = 5.7 mm) Preferably set).

  By setting each thickness dimension t1, t2, and t3 to the above values, stress concentration can be avoided even if the length dimension of the leg blade 20 is 330 mm or more, more specifically, about 345 mm. , Ensuring the design strength and appropriately sharing the load are satisfactorily achieved (note that at least the length of the leg blade 20 is approximately 360 mm). Moreover, the full width dimension W in the longitudinal section in the direction orthogonal to the longitudinal direction of the leg blades 20 is set to about 35 mm, which is equivalent to the full width dimension of resin leg blades that have been widely used conventionally, or smaller (that is, 35 mm). mm or less). That is, the resin leg blades that have been widely used in the past have a large length of about 330 mm, whereas the leg blades 20 having the above-described configuration have a resin leg blade that has been conventionally used in general. While the longitudinal dimension of the leg blade 20 is made larger than that of the leg blade, the strength can be ensured without excessively increasing the weight or impairing the appearance.

  In addition, the length dimension of the leg blade 20 is the axial center of the support shaft of the caster 4 at the distal end portion 20b from the center position (that is, the axial center position) of the through-hole 11 (leg post supporting cylinder portion 12) in plan view. It is a dimension to the position of the center of gravity of the position or the ground contact portion.

  The boundary position between the upper part 21A and the lower part 21B (the ratio between the upper part 21A and the lower part 21B in the vertical direction of the side plate 21 is thereby specified) is limited to a specific position. Rather than avoiding local stress concentration in the leg blade 20 when a load is applied to the leg base 2 by sitting, ensuring the design strength required for the leg blade 20, and the longitudinal direction of the leg blade 20 In consideration of appropriately sharing the load in the entire longitudinal section in the direction perpendicular to the direction, the position is appropriately set. Specifically, for example, the ratio of the lower portion 21B to the overall dimension of the side plate 21 in the vertical direction is preferably set in a range of approximately 30 to 70%, and is set in a range of approximately 40 to 60%. More preferably.

  In addition, as the leg blades of the leg base of the chair, the pair of side plates 21, 21 is provided to provide basic rigidity mainly by the pair of side plates 21, 21 provided opposite to each other and to reinforce the insufficient torsional strength. 21 may further include a structure called a side rib or a cross rib that extends in a direction intersecting with 21 and connects between the pair of side plates 21 and 21.

  In this case, the side rib and the cross rib may be provided in a direction inclined with respect to the longitudinal direction of the side plate 21 as long as the pair of side plates 21 and 21 are connected to each other. You may be allowed to.

  According to the leg base of the chair having the leg blade 20 having the above configuration and the chair having the leg base, the side plate 21 of the leg blade 20 is made thicker in the lower part 21B than in the upper part 21A. The load applied to the leg base 2 when seated on the chair can be appropriately shared by the entire leg blade 20, specifically, by the entire longitudinal section in the direction perpendicular to the longitudinal direction of the leg blade 20. It is possible to increase the longitudinal dimension of the resin leg blade 20 without providing a large number of side ribs or increasing the outer dimensions of the leg blade 20 (in other words, making the entire leg blade 20 thick). Become. For this reason, it is possible to ensure the strength without increasing the weight or impairing the appearance while increasing the longitudinal dimension of the resin leg blades. In addition, the structure of the leg wing | blade in the above-mentioned embodiment can be widely applied with respect to the leg wing | blade of the various leg bases which are a leg wing | blade type, The structure aspect of the base part of a leg base is in the above-mentioned embodiment. The specific structure of the base 10 is not limited.

  On the other hand, as shown in FIG. 15, the synchro frame 8 in the locking mechanism is a synchro frame rotation shaft that penetrates the bearing portion 40 slightly in front of the leg column receiving portion 31 to which the leg column 3 of the main frame 5 is connected. 32 are connected so as to be swingable along the vertical plane. Further, as shown in FIG. 17, the synchro frame 8 is bifurcated in the fore-and-aft direction in front of the sync frame rotation shaft 32, and the upper side is formed as a lever link portion 8a and the lower side is formed as a reaction force spring receiving portion 8b. Has been. That is, the synchro frame 8 has a lever link portion 8a that extends obliquely upward and forward and is rotatably connected to the vicinity of the center of the seat outer shell 6 near the rear, and a reaction force spring receiving portion that extends obliquely downward and forward. 8 b is provided so as to support the rear end portion of the reaction force applying mechanism 37 via the reaction force applying mechanism receiving shaft 33. On the other hand, as shown in FIG. 11, the front of the seat outer shell 6 is preferably above the horizontal plane by a front link 30 that is swingably provided on a bearing bracket portion 38 provided at the front end of the main frame 5. However, it is supported so as to be swingable within a range not reaching the vertical plane, for example, between 20 ° and 30 ° to less than 90 °. When the seated person leans on the backrest 9, the seat outer shell 6 is lifted obliquely upward and rearward by the lever link portion 8 a by the backward tilting operation of the synchro frame 8 around the synchro frame rotation shaft 32. However, the front link 30 connected to the front of the seat outer shell 6 is raised to lift the seat outer shell 6 as a whole, and the coil spring 36 of the reaction force applying mechanism 37 is contracted to generate a reaction force. That is, the locking mechanism of the present embodiment uses both the weight-corresponding reaction force application mechanism and the reaction force application mechanism 37 using the coil spring 36.

  The main frame 5 supports the backrest 9 and the seat 7 through the sync frame 8 and the front link 30 so as to be swingable, and is rotatably mounted on the leg 1. At least the sync frame 8 and the seat are supported by the main frame 5. It suffices to have a portion that supports the outer shell 6 and rigidity, and is not limited to a specific structure, shape, material, or the like. In the case of the present embodiment, as shown in FIGS. 15 and 16, the main frame 5 includes, for example, a pedestal receiving part 31 fixed to the top of the pedestal 3 by an interference fit, and a front end of the reaction force applying mechanism 37. One of the members constituting the lock mechanism 76 among the front end plate 39 for receiving and supporting, the bearing portion 40 for rotatably supporting the synchro frame rotating shaft 32, the bearing bracket portion 38 for rotatably supporting the front link 30 and the synchro frame 8 ( For example, a rear wall portion 41) having an engagement hole 77 and a space 42 in which the reaction force applying mechanism 37 is disposed are provided.

  Between the main frame 5 and the sync frame 8, there is provided a reaction force applying mechanism 37 that generates a reaction force that compresses the sync frame 8 when the sync frame 8 tilts backward and tries to stand the sync frame 8. For example, as shown in FIGS. 11 and 15, the reaction force application mechanism 37 is configured by front and rear spring mounts 34 and 35 and a coil spring 36, and is disposed immediately below the center of the main frame 5. Yes. For example, the reaction force applying mechanism receiving shaft 33 at the tip of the synchro frame 5 via the rear spring mount 35 and the front end plate 39 at the tip of the main frame 5 via the front spring mount 34 are disposed. The front spring mount 34 has a recess 34 a into which a spherical surface at the tip of an adjustment screw (not shown) is fitted, and a shaft portion 34 b that engages with an inverted U-shaped bearing portion (not shown) of the main frame 5. Is provided with a semicircular hook 35 a that engages with the reaction force applying mechanism receiving shaft 33. For example, the front end plate 39 that hangs down from the front end of the main frame 5 is provided with a screw hole 39a and an adjustment screw (not shown) whose tip is formed into a spherical surface. By changing the initial compression amount of the coil spring 36, the strength of the reaction force generated can be adjusted. Further, the spherical surface at the tip of the adjusting screw 21 forms a spherical seat with the recess 34 a provided in the front spring mount 34.

  According to the locking mechanism configured as described above, when the seated person leans on the backrest 9, the backrest 9 and the synchro frame 8 are synchronized while the coil spring 36 is compressed (the reaction force is applied to the backrest). It tilts backward about the frame rotation axis 32. At the same time, the seat outer shell 6 is lifted rearward by the swinging of the lever link portion 8a at the front end of the synchro frame 8 and the front link 30, so that the weight of the seated person on the seat 5 is converted into a force that pushes the backrest 9 back. It acts on the synchro frame 8 as a reaction force. For this reason, the heavier the person, the greater the force required to tilt the backrest, and the lighter the weight, the smaller the force required to tilt the backrest. That is, the thing of the magnitude | size according to a seated person's weight can be obtained as a rocking reaction force with respect to the force which makes a back tilt backward. On the other hand, when the seated person tries to raise his / her upper body, the sync spring 8 rotates in the direction in which the coil spring 36 extends and causes backrest with the action of the rocking reaction force caused by the weight.

  In the case of the present embodiment, the locking mechanism is considered so as not to be exposed to the outside by the front cover 5a covering the lower part of the main frame 5, the rear cover 5b, and the upper cover 5c covering the upper part of the main frame 5. Further, the leg body 1 in this embodiment is a so-called rotating leg provided with casters 4 at the tips of, for example, five leg bases 2 that spread radially, but may be a fixed leg in some cases.

  In this embodiment, a weight-based reaction force applying mechanism that generates a force to push back the backrest 9 by raising the seat 7 in conjunction with the backward tilting of the backrest 9 of the chair and a spring are used. Although the example applied to the synchro-rocking mechanism used together with the reaction force applying mechanism 37 is described, the chair to which the present invention is applied is not particularly limited to this, and the weight-corresponding reaction force applying mechanism and A chair having only one of the reaction force application mechanism 37 having a coil spring, for example, a non-weight sensing synchroclocking in which the rear end side sinks while the seat 7 moves backward in conjunction with the backward tilt of the backrest 9 Needless to say, the present invention can also be applied to a mechanism, a locking mechanism in which only the backrest 9 is tilted backward alone, a locking mechanism in which only the seat 7 performs a locking operation, and a chair having no locking mechanism. . Further, the specific shapes and modes of the constituent members such as the main frame 5, the seat outer shell 6, and the synchro frame 8 to which the present invention can be applied are not limited to those in the above-described embodiment, and are used for a chair. It is appropriately selected based on the design and the like.

  The seat 7 mounted on the above-described locking mechanism is, for example, as shown in FIGS. 12 to 14, a seat that is swingably supported with respect to the main frame 5 with a front link 30 and a sync frame 8 interposed therebetween. The outer shell 6, the inner shell 44 serving as a core, a cushion placed thereon, and an overlying fabric covering the cushion. The inner shell 44 is provided with slits 45 for sliding in the front-rear direction at four corners, and a slider part 46 that passes through the slit 45 is fixed to the seat outer shell 6 side by screws. Therefore, the seat 7 including the inner shell 44 on the seat outer shell 6 is placed along the slit 45 so as to be slidable back and forth. The sliding of the seat 7 in the front-rear direction is restricted by the fitting of a plurality of positioning holes 47 arranged in the front-rear direction on the seat outer shell 6 side and a stopper 48 protruding from the inner shell 44. The stopper 48 moves up and down by the elasticity of the urethane cushion of the seat, and the stopper 48 protrudes from the positioning hole 47 by pushing the head of the stopper 48 protruding outside the seat outer shell 6 toward the seat outer shell 6. So that the lock is released.

  The seat 7 is rotatably supported at the front of the seat outer shell 6 with respect to a seat front support shaft 49 supported at both ends by a pair of front links 30 provided at the front end of the main frame 5. The center of the seat outer shell 6 is swingably connected to and supported by the lever link portion 8a of the sync frame 8 by the rear support shaft 50. As a result, the back of the seat 7 moves up and down as the sync frame 8 swings and swings while the front slides back and forth, and the backrest 9 and the seat 7 perform a locking operation in conjunction with each other.

  The seat 7 is attached to the main frame 5 by passing the seat front support shaft 49 through the bearing bracket portion 51 formed in front of the bottom surface of the seat outer shell 6, and the other end of the front link 30 at both ends of the support shaft 49. The side is fitted. One end / base end side of the front link 30 is rotatably supported by a front link shaft rotatably supported by a bearing bracket portion 38 on the front end side of the main frame 5. Therefore, by rotating the front link 30 about the front link shaft, the front of the seat 7 is supported so as to rise while moving backward and to move downward while moving forward.

  As shown in FIG. 19, the bearing bracket portion 52 of the seat outer shell 6 that supports the seat rear support shaft 50 is received so that the outer bearing portion 52 f that penetrates the seat rear support shaft 6 and the seat rear support shaft 6 do not penetrate. The inner bearing portion 52b is formed with slits 52s for sandwiching the left and right lever link portions 8a of the sync frame 8 between them. That is, the seat outer shell 6 and the lever link portion 8a are constituted by the bearing bracket portion 52 and the two seat rear support shafts 50, each of which includes two sets of the outer bearing portion 52f and the inner bearing portion 52b that sandwich the left and right lever link portions 8a. Are connected. Therefore, the seat outer shell 6 is inserted by inserting the hole 50a portion of the lever link portion 8a of the synchro frame 8 that penetrates the seat rear support shaft 50 into the slit 52s and then inserting the seat rear support shaft 50 from the outer bearing portion 52f. And the synchro frame 8 are rotatably connected.

  This seat rear support shaft 50 is merely inserted into the shaft hole 52h of the bearing bracket portion 52, and is not prevented from coming off by a retaining ring or press fitting. Therefore, although it does not come out to the back side of the bearing bracket portion 52, it may fall out to the near side. Therefore, a seat outer mounting cap 53 is arranged outside the seat rear support shaft 50 so as to be blinded and prevented from coming off. For example, as shown in FIG. 19, the seat outer mounting cap 53 is provided at a through hole (through hole in the thickness direction of the seat outer shell 6) 54 formed at the base portion of the bearing bracket portion 52 and the top portion of the outer bearing portion 52f. It has elastic claws 53a and 53b that are respectively hooked on the notches 52c and is detachably attached to the seat outer shell 6. Here, the elastic claw 53 a that engages with the through hole 54 of the seat outer shell 6 is bent in, for example, a reverse shape, and after elastically deforming and passing through the through hole 54, the tip end side of the seat outer shell 6 is widened. It is provided so as not to get caught inside. Further, the elastic claw 53b hooked on the notch 52c at the top of the outer bearing portion 52f includes, for example, a protrusion hooked on a recess (not shown) at the back of the notch 52c, and the seat outer mounting cap 53 of the seat outer mounting cap 53 is fitted by the uneven fitting. The stopper in the axial direction is intended.

  Further, as shown in FIG. 15, the front link 30 is provided with a stopper lever 55 that functions as a stopper to define one stroke end of the front link 30. The stopper lever 55 is used so as to abut against the front end surface of the main frame 5 and not further forward. For example, as shown in FIGS. 15 and 16, the front end surface of the main frame 5 is integrally formed with the front link 30 adjacent to the bearing bracket portion 38 that swingably supports the front link 30. A groove 56 into which the stopper lever 55 can enter is provided. The wall surface at the end of the groove 56 functions as a degree of contact, and the stopper lever 55 that comes into contact with the wall 56 prevents further forward rotation of the front link 30, that is, lowering of the seat 7 in front. In the case of this embodiment, as shown in FIG. 15, the stopper lever 55 is formed so that the phase advances by, for example, 120 degrees with respect to the front link 30, and the stopper lever 55 contacts the main frame 5. When in contact, the front link 30 is provided so as to be held in a state of being lifted by about 30 °.

  A damper 43 that restricts the maximum tilt position at which the sync frame 8 can swing, that is, the position at which the backrest 9 can tilt to the maximum extent, is provided so as to protrude to the bottom surface side of the main frame 5. When the reaction force applying mechanism receiving shaft 33 of the synchro frame 8 comes into contact with the damper 43, the stopper 43 functions to prevent further rotation of the synchro frame 8 in the backward tilt direction. The damper 43 has a pin shape having a head having a material having an interference function, such as a hard urethane cushion, and is fixed by being fitted into the main frame 5 by press fitting.

  Further, a bearing bracket portion 38 to which the front link 30 that supports the seat front support shaft 49 is swingably attached is formed on the front end side of the main frame 5. The bearing bracket portion 38 is integrally formed with the main frame 5, and supports the front link 30 by a seat front support shaft 49 in a swingable manner at a position away from the main frame 5.

  As shown in FIGS. 1 and 11, the backrest 9 includes a rigid back frame 57, a flexible back frame 58, a mesh tension fabric 59 stretched on the back frame 58, and a lumbar plate that supports the waist (FIG. 11). (Not shown in the figure). As shown in FIG. 11 and FIG. 21, the rigid back frame 57 includes, for example, a backrest portion 57a bent in a generally U shape in a side view and a downwardly supporting back support portion that extends downward. 57b, and has excellent strength such as nylon containing glass fiber, polyamide resin such as polyacetal (POM), polypropylene (PP), nylon, or other materials such as iron, aluminum alloy, stainless steel, etc. Use is also possible.

  A back frame mounting seat 57d is integrally formed on the back support collar portion 57b of the back frame 57 so as to straddle between the left and right back support collar portions 57b, and each tip portion is slightly upward and forward A U-shaped cutout 57f that is open toward the top is formed. The notch 57f is opened toward the inner surface of the back support rod portion 57b and the front end surface. Accordingly, the U-shaped notch 57f at the tip is hooked on the sync frame rotating shaft 32, and then the back frame 57 is rotated around the rotating shaft 32 so that the back frame 57 is tilted backward. The synchro frame 8 and the back frame 57 are integrated with each other by mounting on the back frame mounting bridge portion 8 and fixing with a screw.

  A plurality of recesses 57g for attaching the upper side 58c of the back frame 58 are provided on the upper side of the back frame 57. And it integrates by screwing from the bottom in the state which inserted the convex part (illustration omitted) which protruded in the back side of the back frame 58 in this recessed part 57g. On the other hand, the lower side portion 58 a of the flexible back frame 58 that is flexible with respect to the rigid back frame 57 is supported by the link member 62 so as to be movable back and forth. That is, as shown in FIGS. 11 and 14, the link mechanism 61 is configured among the back frame 58, the back frame 57, and the link member 62. Accordingly, when the lower end of the back frame 58 is moved rearward by rotating the link member 62 and tilting it backward, the back frame (backrest surface) 58 assumes a slightly forward tilted posture. Further, when the lower end 58a of the back frame 58 is moved forward by tilting the link member 62 forward, the back frame (backrest surface) 58 can take a relatively sleeping state or a relaxed posture. That is, without changing the inclination of the back frame 57 (the same as the inclination as the backrest 9), only the inclination of the backrest surface (the surface formed by the back frame 58 and the mesh tension fabric 59) is relatively inclined forward. It can be set as the structure which can be switched to the state made to stand in and the state to lay down. Here, since the link mechanism 61 is provided so that it can be switched to the front position and the rear position over the thought point, even if the seated person leans on the backrest 9 in both the front position and the rear position, The link member 62 rotates only in the direction in which the link member 62 is pressed against the side surface of the bearing bracket portion 57e of the back frame 57. For this reason, the unexpected situation that the inclination of the back frame (backrest surface) 58 is not intended to be switched does not occur, and it can withstand each load and weight acting at the front position or the rear position.

  As shown in FIGS. 20 and 22 to 28, the link member 62 constituting the link mechanism 61 is made of a synthetic resin molded product composed of an A component 63 and a B component 64 divided into two parts. The bearing bracket portions 57e and 58e of the mating member to be configured are opposed to each other so as to be sandwiched and fastened with a fastening means, for example, a fastening screw 70, so as to be integrated. The A part 63 has a member constituting a plurality of pairs of links, for example, two shaft parts 65, and the B part 64 is provided with a recess 66 for receiving the two shaft parts 65 protruding from the A part 63 side. Yes. In this embodiment, an example in which the link is configured as a single link having two pairs is given. However, the present invention is not particularly limited to this, and in some cases, the link may be configured as a duplex link having three or more pairs. Needless to say. The fastening means for connecting the A part 63 and the B part 64 is preferably a fastening screw 70 that enables disassembly of the parts, but is not particularly limited to this. For example, as a semi-permanent fastening means Use any fastening means such as rivet fastening, fastening method by concave / convex fitting between a shaft part having a swollen head and a recess made of a hole having a smaller diameter than the head, welding or bonding part or all of the fastening means Can do.

  The basic structure of the link member will be described based on the first embodiment of the link member shown in FIGS. A connecting portion 67 that also serves as a spacer for maintaining a constant gap between the A component 63 and the B component 64 is provided between the shaft portion 65 and the receiving portion 66 at both ends constituting the link pair. The connecting portion 67 is provided with a connecting portion main body 67 a having a length corresponding to the gap between the A component 63 and the B component 64 in one of the A component 63 and the B component 64 constituting the link member 62. The receiving part 68 may be provided on the other side. In the case of the present embodiment, as shown in FIGS. 23 and 24, the connecting portion main body 67a having a length corresponding to the gap between the A component 63 and the B component 64 is integrally formed with the B component 64, while the A The receiving portion 68 of the connecting portion main body 67a is integrally formed with the component 63. That is, the connecting portion 67 is integrally formed on the B component 64 side where the recess 66 is integrally formed, and the connecting portion 67 is disposed between the two shaft portions 65 when the A component and the B component are abutted. It is configured as follows. A concave portion 67b (or a convex portion) is formed on the front end surface of the connecting portion main body 67a of the B component 64 that faces the A component 63, and the A component 63 that faces the A component 63 is formed of a convex portion (or a concave portion). A portion 68 is formed, and the convex portion 68 and the concave portion 67b on the distal end surface of the connecting portion main body 67a are fitted to each other to form a stamped joint, thereby ensuring accurate positioning and strength. . Of course, the A component 63 and the B component 64 may be integrated by interposing the connecting portion 67 only by screw fastening with the fastening screw 70 without using the fitting of the irregularities 67b and 68. The connecting portion 67 is not limited to the one protruding from at least one member between the two shaft portions 65, and may be formed to protrude from both the A component 63 and the B component 64. For example, both the A part 63 and the B part 64 are provided with connecting portions 67 having an appropriate length by integral molding, and the connecting parts 67 are abutted and joined to each other in the middle between the A part 63 and the B part 64. Alternatively, both the A component 63 and the B component 64 may be provided with a connecting portion 67 having a length corresponding to the gap between the A component 63 and the B component 64 and connected at a plurality of locations. In some cases, a plurality of connecting portions 67 may be provided on one of the A component 63 and the B component 64.

  Further, as shown in FIGS. 23 and 24, a female thread 69 is formed in the connecting portion main body 67a of the B component 64, and a fastening screw 70 is provided in the receiving portion 68 formed of the convex portion of the facing A component 63. A through hole 71 is formed for passage therethrough. Therefore, after the A part 63 and the B part 64 are positioned by fitting the concave and convex portions of the connecting portion 67 and fitting the shaft portion 65 and the concave portion 66, the A component 63 and the B component 64 are integrated by fastening with the fastening screw 70 at the connecting portion 67. Is done. In the present embodiment, the connecting portion main body 67a is provided with the concave portion 67b and the female screw 69, and the convex portion and the through hole 71 are provided on the receiving portion 68 side of the connecting portion 67. However, the present invention is not limited to this. The connecting portion main body 67a may be provided with a convex portion and the receiving portion 68 side may be provided with a concave portion, the connecting portion main body 67a side may be provided with a through hole 71, and the receiving portion 68 side provided with a female screw 69. good.

  The A component 63 and the B component 64 are made of resin. In this embodiment, polyacetal (POM), polypropylene (PP), polyamide resin such as nylon, or glass fiber nylon can be used. Especially, it is preferable to shape | mold the component which integrally molds the axial part 65 with resin materials with good slidability, for example, polyacetal. In this case, the other part is not necessarily formed of POM, and may be formed of a highly rigid synthetic resin that does not have sufficient slidability.

  Further, as shown in the second embodiment of FIGS. 25 to 28, the link member has an outer side in a state where it is attached between any one part of the link members, for example, the back frame 57 and the back frame 58. As shown in FIG. 25, the B component 64 may be provided with a lever component 72 for swinging the link member 62 so that the link member 62 can be directly driven. For example, in the case of this embodiment in which a lever ring 73 of a design element can be interposed between the lever part 72 and the B part 64 as needed, as shown in FIGS. The rectangular boss part 72b is formed in the boss part 72a of the lever part 72, while the boss part 64a outside the B part 64 is provided with the rectangular shaft part 64b, and the rectangular shaft part 64b and the concave part 72b are formed. By fitting, the B component 64 and the lever component 72 can be assembled in a non-rotatable manner. In this embodiment, a notch 64d is formed at the tip of the rectangular shaft portion 64b of the B component 64, while a notch of the rectangular shaft portion 64b is formed on the inner surface near the entrance of the rectangular recess 72b of the lever component 72. The key part 72c fitted into 64d is integrally formed so as to protrude. As a result, when the rectangular shaft portion 64b of the B component 64 and the rectangular recess portion 72b of the lever component 72 are fitted, the notch 64d and the key portion 72c are simultaneously fitted to the lever B component 64 with respect to the lever component. 72 is provided so as not to idle. Further, a through hole 64 e for allowing the set screw 90 to pass is provided at the center of the shaft portion 64 b of the B component 64, and a screw hole 72 d is formed on the back side of the rectangular recess 72 b of the lever component 72. Therefore, the fastening screw 90 is passed through the through hole 64e of the shaft portion 64b from the inner surface of the B part 64 and screwed into the screw hole 72d of the lever part 72, whereby the lever part 72 and the B part 64 are connected to the lever ring 73. Can be firmly integrated in the state of interposing. As shown in FIG. 26, the lever ring 73 has a plurality of convex portions 73 a that fit into a plurality of concave portions 64 c formed on the end surface of the rectangular shaft portion 64 b on the opposing surface of the lever ring 73. For example, four positions are formed every 90 degrees.

  In the case of the present embodiment, since the design component (lever ring) 73 is interposed between the link member 62 and the lever component 72, the link member 62 and the lever component 72 are formed separately and integrated. However, it is not particularly limited to this. When it is not necessary to mount the lever ring 73, the link member 62, for example, the B component 64 and the lever component 72 may be integrally formed in advance by injection molding, or the link member 62 itself does not need to be driven by a lever. There is no need to provide the lever itself. The lever part 72 for swinging the link member 62 may be provided separately from the link member 62, but the operation mechanism is simpler and the structure is simpler when directly connected to the link member 62. The link member 62 can be easily and easily rotated. In addition, the lever part 72 is provided on a link part such as the B part 64 that is outside the chair in the state of use in order to facilitate the operation. However, the lever part 72 is not particularly limited to this, and in some cases, it can be easily applied from the outside. In order to prevent operation, the lever A may be provided on the A component 63 that is inside the chair when in use.

  Between the A part 63 and the B part 64, a bearing bracket part 57e of the back frame 57 which is a part constituting one pair and a bearing bracket part 58e of a back frame 58 which is a part constituting the other pair, respectively. An accommodating space is formed around the shaft portion 65. These voids are spaces for accommodating the bearing bracket portions 57e and 58e, which are counterpart components, in a swingable (non-interfering space) portion. In this embodiment, except for the central coupling portion 67. An open space is formed. In this connection, the shape of the connecting portion 67 can basically be an arbitrary shape, but is also affected by the contour shape of the bearing bracket portions 57e and 58e which are counterpart components. On the other hand, considering the overall mechanical strength of the link member 62, it is desirable to form the link member 62 as thick and wide as possible. Therefore, in the case of the present embodiment, as shown in FIGS. 24 and 27 and the like, the arcuate outer peripheral surface of the bearing bracket portion 57e on the back frame 57 side is horizontal, whereas the bearing on the back frame 58 side is horizontal. Since the arc-shaped outer peripheral surface of the bracket portion 58e is formed as a surface inclined so that the outer radius is smaller than the inner radius, the shape of the connecting portion 67 corresponding to this is the bearing on the back frame 57 side. The surface facing the shaft portion 65 attached to the bracket portion 57e has a substantially flat shape parallel to the shaft portion 65, whereas the surface facing the shaft portion 65 attached to the bearing bracket portion 58e of the back frame 58. Is formed on a conical surface that is not parallel to the shaft portion 65 (the surface on which the generatrix is parallel to the arc-shaped outer peripheral surface of the bearing bracket portion 58e of the back frame 58).

  In the present embodiment, one of the components, for example, the A component 63 is formed with two shaft portions 65 that constitute a pair of opposite ends, and the other component, for example, the B component 64 is formed with a recess 66 that supports the shaft portion 65. However, the present invention is not particularly limited to this, and one shaft portion 65 and a recess 66 may be formed in the A component 63 and the B component 64, respectively. For example, the A component 63 may be formed with the shaft portion 65 on the upper side or the lower side, the concave portion 66 on the opposite side, the B component 64 with the shaft portion 65 on the lower side or the upper side, and the concave portion 66 on the opposite side. good. In addition, in the case of the present embodiment, the shaft portion 65 has a bottomed cylindrical shape in order to make the thickness of the resin molded product uniform. However, the shaft portion 65 is not particularly limited to this and is solid in some cases. It is good as an axis. Further, the shaft portion 65 may be formed in a hollow cylindrical shape in a completely penetrating state depending on the case so that a metal rotating shaft can be passed therethrough. Even in this case, if one component with which the shaft portion 65 is integrally formed is made of a resin material having good slidability, for example, POM, it is difficult to generate sound or rotate without using a collar or bush. It will never become. Moreover, when it is set as the shaft part 65 penetrated completely, you may make it fasten the A component 63 and the B component 64 by a fastening screw or a rivet using this shaft part. In this case, the fastening by the fastening screw 70 in the connecting portion 67 and the fastening in the shaft portion 65 can be used together to achieve fastening at three points, and in some cases, by the fastening screw 70 in the connecting portion 67. Instead of fastening, it is also possible to perform only fastening at the shaft portion 65. In the case where the shaft portion 65 itself also serves as a connecting portion, the illustrated connecting portion 67 may be omitted. Further, in the case where the connecting portion 67 independent of the shaft portion 65 is provided, in the present embodiment, the description is mainly given with an example of being arranged between the shaft portion 65 and the shaft portion 65, but this is not particularly limited to this. The position is appropriately selected as necessary, and may be arranged outside the region between the shaft 65 and the shaft 65 in some cases.

  Further, as shown in FIGS. 24 and 27, contact surfaces (stoppers) 67 c that come into contact with the bearing bracket portion 58 e on the back frame 58 side are formed at both ends of the connecting portion main body 67 in the swing direction. The contact surface 67c contacts the side surface of the bearing bracket portion 58e to prevent the link member 62 from further swinging.

  As described above, the shaft portion 65 that constitutes the pair of the link member 62 has a structure in which the A component 63 and the B component 64 are both supported, so that the structure is strengthened structurally. Further, since the shaft portion 65 is made of resin integrally molded with the A component 63 or the B component 64, the movement becomes smooth.

  Further, the link member 62 is formed by integrally forming two paired shaft portions 65 on one part, particularly the A part 63 arranged inside the back frame 58, so that the back frame 57 and the back frame 58 are By passing the shaft portion 65 through the bearing bracket portions 57e and 58e from the inside, the bearing bracket portions 57e and 58e of both the back frame 57 and the back frame 58 are positioned, and both the bearing bracket portions 57e and 58e are positioned. The center connecting portion 67 and the receiving portion 68 are simultaneously fitted together by simply assembling the shaft portion 65 penetrating through the shaft portion 65 so as to fit the concave portion 66 of the B component 64, thereby facilitating assembly. In addition, since the fastening screw 70 can be screwed in from the inner A component 63 side and the fastening can be completed, the degree of exposure of the screw is small and the appearance is not often impaired.

  In the present embodiment, as shown in FIG. 11, the upper sides 57 c and 58 c of the back frame 57 and the back frame 58 are fixed, while the lower side 58 a side of the back frame 58 and the back support rod portion 57 b of the back frame 57. However, the present invention is not limited to this, and in some cases, the lower side 58a is not limited to this. The side may be fixed, and the link mechanism 61 may be configured on the upper sides 57 c and 58 c so that the upper side 58 c side of the back frame 58 can be moved in the front-rear direction with respect to the back frame 57. In addition, the upper end 58c and the lower end 58a of the back frame 58 are fixed to the back frame 57, while a link mechanism 61 is formed in the middle part of the back frame 58 so that the middle part of the back frame 58 can be deformed by moving back and forth. good. Furthermore, in the present embodiment, the switching by the link mechanism 61 is two positions of the front position and the rear position, but is not particularly limited to this, and switching to three or more positions may be possible.

  On the other hand, as shown in FIG. 1, a lumbar plate 60 is attached to the back frame 58 in the vicinity of the waist, and a tension fabric 59 constituting a backrest surface is attached to the entire front surface. For example, in the present embodiment, as shown in FIG. 23, a groove 58d for inserting the tension fabric 59 is continuously formed in the outer peripheral portions 58b and 58c of the back frame 58, and a relatively soft resin cord (not shown) ) Is sewn into the groove 58d by folding the edge of the mesh tensioned fabric 59 with the resin cord portion folded back. Since the edge of the mesh tension fabric 59 is pushed into the groove 58d while being pulled, tension is applied to the tension fabric 59 and the mesh tension fabric 59 is fixed to the back frame 58. Of course, the structure of the backrest 9 is not limited to the combination of the above-described back frame 58 and the elastic mesh fabric 59, and is made of a cushion material such as urethane, a tension material covering the cushion material, and a shell material that supports the cushion material. It may be configured.

  Here, since the back frame 58 is difficult to form a groove 58d for attaching the mesh tension fabric 59 to the entire circumference due to a problem of the mold structure, as shown in FIG. 32, in the lower side 58a portion of the back frame 58, A separate member having a groove 58d into which the mesh tension fabric 59 is fitted is prepared, and this separate member is screwed to the lower side 58a of the back frame 58 to form the groove 58d on the entire circumference.

  As shown in FIG. 30, the grooved plate 74 as another member is formed with a groove 58 d for pushing the edge of the mesh tension fabric 59. The grooved plate 74 is fixed to the lower side 58 a of the back frame 58 by screwing, and the back frame 58 And are integrated. The left and right end portions of the grooved plate 74 are deformed in a direction that rises with respect to the front surface of the back frame 58, that is, the surface of the back frame 58, so that a gap is formed between the groove plate 74 and the back frame. A stepped portion 74a to be formed is formed. The stepped portion 74a is provided with a lumbar plate locking claw 75 that exhibits springiness in the front-rear direction. The locking claw 75 is provided so as to be deformable with respect to the lumbar plate 60 by forming a narrow space (slit) 75b surrounding three sides of the locking claw 75. Further, a triangular protrusion 75a is provided on the surface of the front end (lower end) of the locking claw 75 facing the back frame 58 so that the bottom side is disposed on the front end side.

    On the other hand, as shown in FIG. 31, the lumbar plate 60 is formed of a flexible synthetic resin, and includes a lumbar support portion 60 a made of a curved surface that curves up, down, left, and right to support the waist of the seated person, and a back frame 58. And both side edge portions 60b that support the lumbar support portion 60a. In addition, at the lower end of both side edge portions 60b of the lumbar plate 60, a through hole or a concave portion such as a square hole 60d that engages with the engaging claw 75 of the grooved plate 74 is provided. Also, ribs 60e are formed on both side edges 60b along the back frame 58 of the lumbar plate 60. The collar rib 60e is inserted into a collar groove 58f (see FIG. 29) formed on the back frame 58 side to prevent the lumbar plate 60 from moving in the left-right direction. In addition, since the lumbar plate 60 is disposed on the back side of the mesh tension ground 59, the front side of the lumbar plate 60 is restrained by the mesh tension ground 59, and therefore does not move forward.

  Accordingly, when the lower end 60c of the side edge portion 60b of the lumbar plate 60 is inserted from above toward the gap between the stepped portion 74a of the grooved plate 74 and the back frame 58, the triangular protrusion 75a is formed in the void 75b. The projection 75a returns to the original position at the same time as the square hole 60d of the lumbar plate 60 passes, and the engagement claw 75 is fitted into the square hole 60d of the lumbar plate 60 to engage the two (see FIG. 32). ). Subsequent movement of pulling up both side edge portions 60b of the lumbar plate 60 upwards is generated by the protrusion 75a of the engaging claw 75 being caught on the edge of the square hole 60d. At the same time, the ribs 60e on both sides of the lumbar plate 60 are fitted into the grooves 58f of the back frame 58, so that no displacement or omission occurs in the left-right direction. Further, since the mesh tension fabric 59 exists on the front side (the side facing the back of the seated person) of the lumbar support portion 60a and the back frame 58 exists on the back side of the side edge portions 60b, The slippage in the front-rear direction is also prevented. Therefore, the lumbar plate 60 is fixed to the grooved plate 74 and the back frame 58.

  Here, the locking mechanism according to the present embodiment is provided with a locking mechanism 76 between the main frame 5 and the synchro frame 8 that can fix the tilting posture in a stepwise manner when the synchro frame 8 is tilted backward. It is provided so as to be fixed at the rearward tilt position. For example, as shown in FIG. 16, the lock mechanism 76 is provided with a plurality of engagement holes 77 in the rear wall portion 41 of the main frame 5, and synchronizes a lock plate 78 that is selectively fitted into the engagement holes 77. The frame 8 is configured to be capable of appearing and retracting.

  Therefore, in the case of the present embodiment, the sync frame 8 is a pair of right and left flat plates having the same shape as shown in FIG. The synchronized frame joint 79 and the reaction force applying mechanism receiving shaft 33 which are connected and integrated are connected and integrated. The sync frame 8, the sync frame joint 79, and the reaction force applying mechanism receiving shaft 33 are integrated by welding to form one structure. Reference numeral 32a in the figure is a hole through which the sync frame rotating shaft 32 passes.

  The synchro frame joint 79 includes a back frame fixing seat 80 to which a backrest is attached, and a U-shaped guide portion 81 that slidably supports a lock plate 78 of the lock mechanism 76. The back frame fixing seat 80 is provided with four screw holes 83 for fixing the back frame mounting seat 57d of the back frame 57 by welding a nut to the back surface side. The flange portion 57b can be screwed. In addition, a screw hole 84 and a wire through hole 85 are provided for attaching a stopper operation arm mounting mount 86 disposed so as to straddle the back frame fixing seat 80 and the U-shaped guide portion 81. A stopper operating arm mounting mount 86 is fixed to the back side of the back frame fixing seat 80 by fastening screws 86b and locking claws 86c. The locking claw 86 c is inserted into a hole formed in the bottom of the U-groove guide portion 81 and then hooked on the bottom of the U-groove guide portion 81. As shown in FIG. 18, the stopper operating arm mounting mount 86 includes a lock plate 78, a drive lever 87 that drives the lock plate 78, a torsion coil spring 88 that transmits the swing of the drive lever 87 to the lock plate 78, A compression coil spring 89 that constantly urges the lock plate 78 toward the main frame 5 is accommodated, and a drive lever 87 that is rotatably fitted to the cross shaft 86a is supported to be swingable in the front-rear direction by a wire operation. doing. In the figure, reference numeral 78a is a hole for hooking the torsion coil spring 88, and 78b is a protrusion fitted into the engagement hole 77 on the main frame 5 side.

  The synchro frame joint 79 is formed by integrally forming, for example, a U-shaped guide portion 81 and a back frame fixing seat 80 straddling between the left and right synchro frames 8 by bending. Of course, the U-shaped guide part 81 and the back frame fixing seat 80 may be formed separately and attached to the synchro frame 8 by welding or the like. The U-groove guide portion 81 has higher strength than a simple flat plate joint, and is provided with slits 82 that allow the lock plate 78 to pass through the front and rear wall portions 81a and 81b. It can be set as the both-ends support which supports a rear-end part so that sliding is possible.

  Here, the lock mechanism 76 preferably has a self-holding function by interposing a spring in the mechanism. For example, as shown in FIG. 18, the self-holding mechanism includes a drive lever 87 that swings in the sliding direction of the lock plate 78 by a wire operation using a locking operation lever (not shown), and an engagement of the lock plate 78 on the main frame 5 side. A compression coil spring 89 that is constantly urged toward the hole 77, and a torsion coil spring 88 that is interposed between the lock plate 78 and the drive lever 87 and transmits the movement of the drive lever 87 to the lock plate 78, and includes a locking operation. When the lock plate 78 cannot follow the lever locking or unlocking operation, the torsional deformation of the torsion coil spring 88 separates the linkage operation of the drive lever 87 and the lock plate 78 and absorbs the displacement of the drive lever 87 to spring. The main frame on the lock plate 78 is stored as force. The lock plate 78 by the spring force the frictional force stored in the coil spring 88 twists when it is alleviated between the arm 5 is intended to withdrawn from Dari or engaging hole 77 pushed toward the engaging hole 77. The torsion coil spring 88 that interlocks the lock plate 78 and the drive lever 87 passes through a thought point while the drive lever 87 swings between the lock position and the unlock position, and is applied to the lock plate 78. It is arranged so that the direction of is reversed. That is, the self-holding function of the lock mechanism 76 is that the lock plate 78 can slide when the lock plate 78 cannot be switched even if the lock state is switched by the drive lever 87 by the operation of the locking operation lever. This means that the state of the drive lever 87 is maintained until the situation is reached. The compression coil spring 89 is weaker than the torsion coil spring 88, and preferably has a strength relationship in which the torsion coil spring 88 contracts after the compression coil spring 89 first contracts with a force acting in the same direction.

  The engagement hole 77 of the rear wall portion 41 of the main frame 5 is formed as, for example, a horizontally long rectangular through hole. The engagement holes 77 are provided in a plurality of stages at intervals in the direction in which the sync frame 8 swings (that is, the vertical direction), and the direction orthogonal to the direction in which the sync frame 8 swings (that is, the direction) A plurality of rows are arranged in the left-right direction with a space therebetween. Correspondingly, a plurality of rows of protrusions 78b are provided at the tip of the lock plate 78, and are provided so as to be simultaneously fitted into the plurality of rows of engaging holes 77 in the same step. In this embodiment, the engagement hole 77 is formed as a through hole, but may be a recess. In addition, the number of steps and rows of the engagement holes 77 and the distance between them in the vertical direction are not limited to a specific number or value, but a tilt range that is preferable as a mechanism for tilting and fixing the backrest and fixing the tilting operation. In consideration of the number of possible positions and / or the pitch of the tilt angle at the time of fixing, the number and value are appropriately set. Three rows are arranged in the direction. Further, the engagement hole 77 may be provided in a separate part and attached to the main frame, or the lock hole 78 may be provided on the main frame side and the engagement hole 77 may be provided on the synchro frame 8 side.

  Although the above-described embodiment is an example of a preferred embodiment for carrying out the present invention, the embodiment of the present invention is not limited to the above-described embodiment, and the present invention is not limited to the scope of the present invention. The invention can be variously modified.

  For example, in the above-described embodiment, an example in which the link member of the present invention is applied to a mechanism that tilts the back frame / backrest surface by moving the lower end of the back frame of the backrest of the weight sensing type synchro-rocking chair back and forth. Although mainly described, the present invention is not particularly limited thereto, and may be used for connection between other members of the chair that rotate around the axis. As an example, it may be applied to the front link 30 for raising and lowering the front of the seat 7 in conjunction with the movement of the synchro frame 8. In this case, a bearing bracket portion (not shown) having the same width is provided on the back surface side of the seat outer shell 6 at a position corresponding to the bearing bracket portion 38 of the main frame 5, and the A component 63 so as to sandwich the both bearing bracket portions. The link mechanism 61 including the seat outer shell 6 and the main frame 5 is configured by screwing the B component 64 in combination. In the case of this link mechanism 61, there is an advantage that a relatively long stainless steel rotating shaft penetrating the left and right bearing bracket portions is not required.

  Furthermore, depending on the case, the upper sides 57c and 58c of the back frame 57 and the back frame 58 may be connected by the link member 62 so that the distance between the upper side 58c of the back frame 58 and the upper side 57c of the back frame 57 can be adjusted. In this case, the lower side 58a of the back frame 58 is fixed to the back frame 57, and the inclination of the back frame 58 itself is adjusted by the bending of the back frame 58. In some cases, the lumbar plate 60 may be moved back and forth, that is, the link member 62 may be used to adjust the force to support the waist. In this case, bearing bracket portions are formed on the upper side 57c of the back frame 57 and the upper side 58c of the back frame 58, respectively, and the A part 63 and the B part 64 arranged so as to sandwich the bearing bracket part are mutually connected to the shaft parts 65. And the recess 66 are fitted together so that the connecting portion 67 serving as a spacer is fastened by a fastening means such as a fastening screw 70.

    In the above-described embodiment, the aluminum die-cast main frame is used. However, the main frame is not particularly limited to this, and if the main frame has a supporting structure and rigidity, the steel plate is bent by press working. It goes without saying that a main frame or the like may be used and is not limited to a specific structure or shape.

9 Backrest 57 Back frame 57b Back support 57c Upper side 57e Bearing bracket part 57g Recessed part 58 Back frame 58a Lower side 58c Upper side 58e Bearing bracket part
59 Mesh tension 61 Link mechanism 62 Link member 63 A part 64 B part 64a Boss part 64b Rectangular shaft part 64c Recessed part 64d Notch 64e Through hole 65 Shaft part 66 Recessed part 67 Connecting part 67a Connecting part main body 67b Recessed part 67c Degree of contact 68 Receiving part (convex part)
69 Screw hole 70 Screw for fastening link member 71 Through hole 72 Lever 72a Boss part 72b Rectangular concave part 72c Key part 72d Screw hole 73 Lever ring 73a Convex part

Claims (8)

In a link member of a chair that forms at least two pairs that rotate about an axis between two other members and a link mechanism between the other members,
The link member is a synthetic resin molded product composed of two parts, an A part and a B part,
At least two shaft portions constituting the plurality of pairs and a portion for receiving the shaft portions are formed integrally with any one of the A component and the B component, and either the A component or the B component. It has a connecting part that is formed integrally with one of the parts and connects the A part and the B part,
The A part and the B part face each other so as to sandwich the bearing part of the mating member constituting the kinematic pair, and the shaft part and the part that receives the shaft part are fitted together, and then the A part is connected to the connecting part. A link member for a chair, wherein the B part and the B component are fastened and integrated.   The A part has one of the shaft part and the part that receives the shaft part by integral molding, and the B part has one of the part that receives the shaft part and the shaft part by integral molding. The link member of the chair according to claim 1, wherein the link member is provided.   The link member of the chair according to claim 1 or 2, wherein the connecting portion protrudes from at least one member between the two shaft portions.   The link member of the chair according to claim 1, wherein the connecting portion is also used by the shaft portion itself.   The link member of the chair according to any one of claims 1 to 4, wherein a part having the shaft portion of the A part or the B part is formed of a material having good slidability.   The link member of the chair according to any one of claims 1 to 5, wherein an operation part is formed integrally with at least one of the A part and the B part.   In a backrest that connects a flexible back frame constituting a backrest surface and a rigid back frame at least at one end, the link member is disposed between the back frame and the back frame to provide a link mechanism. The chair link member according to any one of claims 1 to 6, wherein the link member is configured to change the shape of the back frame by swinging the link member over a thought point.   The link member of the chair according to any one of claims 1 to 7, wherein the link member has a contact portion that restricts movement of the link mechanism with the counterpart member.