JP2012085894A - Chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chair, preventing surplus upward urging force other than that of seat urging means from being applied to a seat in sitting to enable comfortable sitting.SOLUTION: A support base 5 and the lower part of a backrest 10 are connected to each other with such a play that the backrest 10 can be turned between the upright position and the backward tilting position by a link member 23, and the support base 5 is provided with downward turn regulating means 2628 for regulating the downward turning amount of the link member 23. Back urging means 32 is provided between the link member 23 and the lower part of the backrest 10, thereby urging the backrest 10 toward the upright position.

Description

  The present invention is a chair, particularly when not in use, the rear part of the seat is lifted, and when the seated person sits, the seat abuts against the seated person's buttocks and rotates to a substantially horizontal position together with the buttocks. Thus, the present invention relates to a chair that guides the seating and also supports the standing up by raising the rear part of the seat when the seated person stands up.

  As a chair of this type, the seat is supported with respect to the lower structure of the chair so as to be rotatable between a use position inclined horizontally or rearwardly downward and a non-use position inclined rearwardly upward, A backrest is pivotally attached to the rear part of the seat so that the backrest can pivot between a standing position and a rearward tilting position, the seat is biased toward a non-use position, and the backrest is directed toward the standing position. By providing each urging means to urge the seat, the seating person can assist in standing up when standing up, and the backrest can be reclined independently while seated, and the seat can be used from the non-use position to the use position. During rotation, there is one that can maintain the backrest in an upright position (see, for example, Patent Documents 1 and 2).

JP 2010-104562 A Japanese Patent No. 4379538

  In the chair described in Patent Document 1, a part of the four-bar linkage mechanism and the lower end of the backrest are directly backed by means such as a gas spring, and in the chair described in Patent Document 2, The rods (links) having back biasing means at the middle in the longitudinal direction can be connected to each other so that the backrest can be reclined independently, and while the seat rotates from the non-use position to the use position, Drowning is kept upright.

  As described above, when a part of the four-bar linkage mechanism and the lower end of the backrest are directly connected by the back biasing means or by a rod having the back biasing means in the middle part in the longitudinal direction, When the four-bar linkage mechanism is rotated and the seat is rotated to the use position, the back biasing means is slightly compressed, and the compression force at that time is transmitted to the seat, so that the seat is directed upward. In addition to the urging force of the urging means, an extra upward urging force by the back urging means is applied, and when sitting on a seat in a rear-up position that is not in use, the downward rotation of the seat may be felt heavy. .

  In order to eliminate such problems, the layout and structure of the four-bar linkage mechanism, the back biasing means against the four-bar linkage mechanism and the backrest, the linkage form of the rod, the expansion / contraction stroke, etc. are appropriately designed and seated. However, it is necessary to prevent excessive upward biasing force from being applied to the seat. However, the four-bar linkage mechanism and back biasing means should be designed appropriately in the limited space below the seat and backrest. It is difficult to incorporate them and the design cost increases.

  The present invention has been made in view of the above-described problems, and when sitting, it is possible to sit comfortably so that an excessive upward biasing force other than the seat biasing means is not applied to the seat. Thus, an object of the present invention is to provide a chair in which the back biasing means is effectively compressed only when the backrest is tilted backward so that the backrest can be reclined comfortably.

According to the present invention, the above-mentioned problems are solved as follows.
(1) A support base supported by a leg, a seat pivotally attached to the support base with a pivot that faces in the left-right direction, and a rear portion that is pivotable vertically between a non-use position and a use position; The base is provided with a seat urging means for urging the rear portion of the seat upward with respect to the pivot shaft, and is pivotally attached to the rear portion of the seat with a support shaft facing in the left-right direction, and rotates between a standing position and a rearward tilt position. In a chair comprising a possible backrest and back biasing means for biasing the backrest to an upright position, a portion of the support base behind the pivot and a portion of the backrest below the support shaft Are connected with play sufficient to allow the backrest to rotate between the standing position and the rearward tilting position, and the downward rotation amount of the link member is regulated by the support base. Provided with a downward rotation restricting means, and the back The energization means, by providing between the lower and the link member and the backrest, so as to urge the backrest to the upright position.

In this way, the support base and the lower end of the backrest are connected by the link member with a play that allows the backrest to rotate between the standing position and the rearward tilt position, and the backrest is connected between the link member and the backrest. Since the biasing means is provided, when sitting on the seat, the back biasing means only pivots downward together with the link member, and the seat has a biasing force other than the upward biasing force, ie, the seat biasing means. No extra upward biasing force is applied. Therefore, the downward rotation of the seat is not felt heavy and the user can sit comfortably.
Further, the downward rotation of the link member is stopped by the downward rotation regulating means, and the back biasing means is effectively compressed by tilting the backrest backward after the seat is rotated to the use position. So you can recline the back comfortably.

(2) In the above item (1), the link member is provided with an arc-shaped long hole centered on the back support shaft, and a connecting shaft facing in the left-right direction is slidably fitted into the long hole. Further, the rear end portion of the link member is connected to the lower end portion of the backrest with a play that allows the backrest to rotate between the standing position and the rearward tilt position, and the back end portion of the link member is attached to the backside. The rear end portion of the biasing means is connected to the lower part of the backrest with the common connecting shaft.

With such a configuration, when the backrest is tilted backward, the connecting shaft at the rear portion of the link member is guided and smoothly moved by the arc-shaped long hole, so that the backrest is excessively applied to the support shaft. It is possible to recline smoothly without applying a bending moment.
In addition, since the rear end portion of the link member and the rear end portion of the back biasing means are pivotally attached to the lower portion of the backrest with a common connecting shaft, the number of parts can be reduced, the structure can be simplified, and the back The pivoting work of the link member to the drooping and the back biasing means becomes easy.

(3) In the above item (2), the link member is shaped like a case having an accommodation recess that opens upward, and long holes are provided on both side walls of the case-like link member, and the back is accommodated in the accommodation recess. The rear end portion of the urging means is supported by the central portion of the connecting shaft that is inserted through the long holes.

  With such a configuration, both ends of the connecting shaft are stably supported by the long holes on both side walls of the link member, and the rear end portion of the back biasing means accommodated in the accommodating recess is the central portion of the connecting shaft. Therefore, the bending force is not applied to the back biasing means, and it can be reliably expanded and contracted in the longitudinal direction.

(4) In the above item (3), the seat urging means and the back urging means are accommodated and assembled in the housing recess of the link member, whereby the link member, the seat urging means and the back urging means are Unitize.

  With such a configuration, the assembly of the link member, the seat biasing means, and the back biasing means to the support base, the seat, and the backrest is improved, so that the chair can be assembled efficiently.

(5) In the above item (3) or (4), the seat urging means and the back urging means are respectively displaced from each other in the front and rear portions in the housing recess of the link member and back and forth. The urging means is accommodated so that it faces upwards obliquely.

With such a configuration, the seat urging means and the back urging means are accommodated in the accommodating recesses of the link member and are not conspicuous, so that the appearance of the chair is good and the height when the seat is in the use position is obtained. Can be lowered.
Further, the seat urging means and the back urging means can be arranged compactly in a limited space below the seat without interfering with each other.

(6) In any one of the above items (3) to (5), the back biasing means is composed of a pair of left and right, and the pair of back biasing means is accommodated in the accommodating recess of the link member. .

  With such a configuration, the urging force of the backrest becomes large, so that a small back urging means can be used, and this can be housed compactly in the housing recess of the link member.

(7) In any one of the above items (1) to (6), the front end portion of the seat biasing means and the front end portion of the link member are pivotally attached to the support base with a common axis facing in the left-right direction.

  With such a configuration, the number of parts is small, the structure can be simplified, and the pivoting operation of the seat biasing means and the link member to the support base is facilitated.

According to the present invention, the seat is not subjected to an excessive upward biasing force other than the seat biasing means, so that the downward rotation of the seat is not felt heavy, and therefore the seat can be comfortably seated. it can.
Further, since the downward rotation of the link member is stopped by the downward rotation restricting means, and the seat is rotated to the use position, the back biasing mechanism is effectively compressed by tilting the backrest backward. Can recline comfortably.

It is a front view in the non-use state of one embodiment of the chair of the present invention. Similarly, it is a side view. Similarly, it is a side view in a use state. Similarly, it is a side view when the backrest is tilted backward in the use state. Similarly, it is an enlarged center vertical side view which shows the center part in the chair of a non-use state, abbreviate | omitting the cushion material of a seat. Similarly, it is an enlarged central longitudinal side view of the chair in use. Similarly, it is the perspective view which looked at the member with which the support base and the support base were mounted | worn from diagonally forward upper direction. It is the perspective view which looked at the link member from diagonally downward. It is a perspective view of a support base. It is a disassembled perspective view of a back biasing means, and a perspective view of the link member in which it is integrated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 4, the chair includes a leg body 3 having five leg rods 2 having a radial shape with a caster 1 at the tip. In the center of the leg 3, an extendable leg 4 having a gas spring (not shown) is erected, and the rear part of the support base 5 facing forward is fixed to the upper end of the leg 4. The support base 5, the pedestal 4 and the leg 3 may be integrated.

  The support base 5 is integrally formed of an aluminum alloy or the like, and as shown in FIG. 7, forms a shallow dish having a triangular shape in plan view that expands forward, and is inclined forward and upward in a side view. . Further, as shown in FIG. 1, the support base 5 has an upward U-shape when viewed from the front and is open to the front. Therefore, when attaching the member to the support base 5, only the side and the rear It is easy to insert a member, a tool, etc. from the front.

  The seat 6 includes a seat plate 7 made of synthetic resin and a cushion material 8 attached to the upper surface of the seat 6. The seat 6 has both front end sides on the front end of the support base 5 and pivots 9 facing left and right. As shown in FIG. 2, each pivotally attaches to a non-use position that tilts backward and upward as shown in FIG. 2 and a use position that tilts horizontally or rearward and downward as shown in FIG. It is possible to move. The rotation range is preferably about 15 degrees. The rotation range of the seat 6 is set so that when the seat 6 is in the use position, the seat occupant is tilted forward to the extent that it does not naturally shift forward, and when it is in the non-use position, the seat 6 is substantially horizontal. May be.

  On both sides of the rear portion of the seat plate 7, there are support shafts 11 facing in the left-right direction so that the front portions of the extending portions 10 a facing the front side from the lower sides of the backrest 10 are located behind the pedestal 4. As shown in FIGS. 2 and 3, the backrest 10 is pivotally mounted, and can be rotated around the support shaft 11 between an upright position substantially facing upward and a rearward tilt position as shown in FIG. 4. ing. The support shaft 11 and the extending portion 10a through which it is inserted are provided with stopper means (not shown) for restricting the backrest 10 from rotating further forward from the standing position.

As shown in FIG. 7, the support base 5 is provided with a seat urging means 12 for urging the rear portion of the seat 6 upward.
The seat urging means 12 includes an elastic expansion / contraction means 13 for connecting a portion of the support base 5 below the pivot 9 and a portion of the seat 6 behind the pivot 9, and a seat 6 on both sides of the elastic expansion / contraction means 13. The front upper end portion is fixed to the lower surface of the base plate, the middle portion is elastically bent into a U-shape that opens forward in a side view, and the front lower end portion is fixed at a position below the pivot 9 in the support base 5. And a pair of left and right elastic bending means 14, 14.

  In this example, as shown in FIGS. 2 and 5 to 7, the elastic expansion / contraction means 13 has a front end pivotally attached to the support base 5 with a base shaft 15 in the left-right direction, and a rear end on the lower surface of the seat 6. A gas spring 17 having no locking function is pivotally attached to an intermediate portion in the front-rear direction with a shaft pin 16 in the left-right direction. However, a gas spring having a locking function, a compression coil spring, an oil damper, an air damper, or the like may be used.

  In this example, each of the left and right elastic bending means 14 is, as shown in FIGS. 18a, an upper piece 18b extending rearward from the upper mounting portion 18a, an elastic bending portion 18c that curves in a substantially semicircular arc from the rear end of the upper piece 18b toward the front lower side, and an elastic bending portion 18c A pair of left and right leaf springs 18 made of synthetic resin having a lower piece 18d extending forward or forward and downward from the lower end of the lower plate 18 and a lower attachment portion 18e provided at the front end of the lower piece 18d for attaching to the support base 5. , 18. Each leaf spring 18 may be made of spring steel.

  The width in the left-right direction of the lower pieces 18d, 18d in the left and right leaf springs 18, 18 is gradually reduced toward the front. This is for avoiding interference with the gas spring 17 described above, the link member 23 and the back biasing means 24 described later, and collectively accommodating them in a narrow space below the seat 6.

  Further, as shown in FIG. 7, the left and right leaf springs 18 and 18 are preferably arranged so that both lower pieces 18 d and 18 d expand rearward in plan view. Furthermore, it is preferable that the upper pieces 18b, 18b are also arranged so as to expand toward the rear in a plan view. By doing in this way, the rear part of the seat 6 can be supported stably.

  Lower mounting portions 18e, 18e in the left and right leaf springs 18, 18 are pivotally attached to both side end portions of the base shaft 15.

  The base shaft 15 is fixed to the upper surface of the front portion of the support base 5 as follows. That is, as shown in FIGS. 5 to 7, a recess 5 a facing in the left-right direction is provided on the bottom surface of the front portion below the pivot 9 in the support base 5, and a plurality of protrusions arranged side by side in the left-right direction in the recess 5 a. The upper surface of the portion 19 is provided with U-shaped concave grooves 20 that open in both the upper and left and right directions. After the base shaft 15 is fitted into each concave groove 20, the presser fitting 21 is disposed on the upper surface of each protrusion 19. By fixing with screws 22, 22, the base shaft 15 is fixed to the upper surface of the front end portion of the support base 5 so as not to rotate (may be rotatable).

Since the seat urging means 12 includes an elastic expansion / contraction means 13 and a pair of left and right elastic bending means 14 disposed on both sides of the elastic expansion / contraction means 13, the rear portion of the seat 6 is attached to the left and right sides. The seat 6 can be lifted with good balance and the seat 6 can be supported stably.
Moreover, since the elastic expansion-contraction means 13 and the elastic bending means 14 can be reduced in size and disposed compactly below the seat 6, the appearance of the chair can be improved.

  As described above, when the elastic expansion / contraction means 13 is a gas spring 17 and the elastic bending means 14 is a leaf spring 18, the structure of the elastic expansion / contraction means 13 and the elastic bending means 14 is simplified and can be manufactured at low cost. it can.

  Further, since the front end portion of the elastic expansion / contraction means 13 and the lower front end portion of the elastic bending means 14 are pivotally attached to the support base 5 with a common base shaft 15 facing in the left-right direction, the structure can be simplified. In addition, the pivoting operation of the elastic expansion / contraction means 13 and the elastic bending means 14 to the support base 5 can be simplified.

The upper surface of the elastic bending portion 18c having a semicircular arc shape when viewed from the side in the leaf spring 18 as the elastic bending means 14 is in contact with the lower surface of the seat 6, and the leaf spring 18 is rotated downward when the seat 6 is rotated downward. By reducing the distance between the upper mounting portion 18a and the lower mounting portion 18e, the lower piece 18d is pushed rearward and upward, and the elastic bending portion 18c gradually moves rearward along the lower surface of the seat 6. The spring 18 is elastically deformed.
By elastically deforming the leaf spring 18 in this way, stress can be prevented from concentrating on the same location of the leaf spring 18, the durability of the leaf spring 18 can be improved, and the reaction force of the leaf spring 18 can be reduced. Can be increased.
As a result, the reaction force of the leaf spring 18 increases as the seat 6 is rotated downward.

As shown in FIGS. 5 to 7, a portion of the support base 5 below the pivot shaft 9 and a portion of the backrest 10 below the support shaft 11 are integrally formed of a hard synthetic resin and facing the front-rear direction. The members 23 are connected. Note that the material of the link member 23 may be an aluminum alloy or the like.
The link member 23 includes a bottom wall 23a, a pair of left and right side walls 23b, 23b, a front wall 23c, and a rear wall 23d. The link member 23 has a long case shape in the front-rear direction. 24 is formed. The front part of the bottom wall 23 a and the front part of the left and right side walls 23 b that are wide in the front-rear direction are bent obliquely forward and downward toward the upper surface of the central part of the support base 5.

Further, the rear portions of the bottom wall 23 a and the left and right side walls 23 b are bent obliquely rearward and upward toward the front surface of the lower end portion of the backrest 10.
The upper surface of almost the rear half of the left and right side walls 23b, 23b of the link member 23 is curved to a downward concave curved surface so as to align with the downward convex arcuate curved surface of the lower surface of the rear half of the seat plate 7, and when seated The lower surface of the rear half of the seat plate 7 can be brought into close contact with or in contact with the upper surface of the rear half of the link member 23 (see FIGS. 5 and 6). Contrary to the above, the upper surface of the rear half of the left and right side walls 23b, 23b may be a concave curved surface, and the lower face of the rear half of the seat plate 7 may be a convex arcuate curved surface.

  The rear end portions of the bottom wall 23a and the side walls 23b extend rearward from the rear wall 23d. In the unused state shown in FIG. 5, the rear end portion of the extended portion 23e of the bottom wall 23a is the backrest 10. When the seat 6 is rotated to the use position so as to be close to the front surface of the lower end of the finger, a finger or the like is prevented from entering between the rear end of the bottom wall 23a and the lower end of the backrest 10. .

  As shown in FIGS. 5 and 8, the front end portion of the link member 23 is formed with a mountain-shaped upward recess 25 by bending the front wall 23c so as to form a mountain-shaped cross section when viewed from the side. Yes. An inclined portion facing obliquely rearward and upward on the front side behind the base shaft 15 in the front wall 23c bent into a mountain-shaped cross section is a stoppered portion 26 that constitutes the downward rotation restricting means of the link member 23 and the seat 6. It has become.

  As shown in FIG. 5 and FIG. 9, an upward convex portion 27 projecting in a side-view mountain shape, into which the upward concave portion 25 can be fitted, projects on the upper surface of the central portion of the support base 5 facing the upward concave portion 25. It is installed. The inclined portion of the upward convex portion 27 that faces obliquely rearward and upward on the front side behind the base shaft 15 is a stopper portion 28 that constitutes the downward rotation restricting means of the link member 23 and the seat 6. That is, the stopper portion 26 and the stopper portion 28 constitute a downward rotation restricting means for the link member 23 and the seat 6, and when the seat 6 is rotated downward to the use position, the lower surface of the stopper portion 26. However, the maximum downward rotation amount of the link member 23 and the seat 6 is regulated by contacting the front surface of the stopper portion 28 with the surface and stopping the downward rotation of the link member 23 (FIG. 6).

  The left and right dimensions of the upward convex portion 27 of the support base 5 are such that the left and right outer surfaces are in sliding contact with the inner surface of the upward concave portion 25 of the link member 23, and the upper portion of the upward convex portion 27 is the seat 6. Even when the is not in use, the link member 23 enters the lower part of the upward recess 25. In this way, the link member 23 and the seat 6 are prevented from wobbling in the left-right direction with respect to the support base 5, and a bending load is prevented from being applied to the pivoted portion at the lower end portion of the link member 23 and the base shaft 15. Is done. Further, the stopper portion 28 is located in the upward concave portion 25, and the stopper portion 26 contacts the stopper portion 28 in the upward concave portion 25. When the 6 rotates downward, it is possible to eliminate the possibility that a finger or the like enters the contact surface between the stopper portion 26 and the stopper portion 28 from the side of the support base 5 and is pinched.

As shown in FIG. 5, the lower surface of the link member 23 behind the stopper portion 26, that is, the lower surface of the bottom wall 23 a continuous with the rear lower edge of the upward recess 25 extends toward the upper surface of the support base 5. A downward bent portion 23f is formed.
Further, a V-shaped cross section formed on the upper surface of the support base 5 immediately after the upward convex portion 27 is formed by the bent portion 23f and an inclined portion 25a that faces the obliquely upward front of the upward concave portion 25 continuous therewith. A fitting groove 5b into which the downward projection 25b can be fitted is formed. Even when the seat 6 shown in FIG. 5 is in the non-use position, the lower end of the downward projection 25b slightly enters the fitting groove 5b so as to be close to the opening edge of the rear part of the fitting groove 5b. It is.

  As described above, when the bent portion 23f is provided on the lower surface behind the upward recess 25 in the link member 23, that is, on the lower surface behind the stopper portion 26, the seat 6 is rotated downward to the use position. Further, there is no possibility that a finger or the like enters the contact surface between the stopper portion 26 and the stopper portion 28 from behind the support base 5 and is pinched.

  Long holes 29 and 29 that face diagonally forward and downward with the support shaft 11 of the backrest 10 as the center are formed in the rear end portions of the left and right side walls 23b and 23b of the link member 23 so as to face each other. By fitting the left and right end portions of the connecting shaft 30 inserted in the left and right direction into the left and right center portions of the front surface of the lower end of the backrest 10, the left and right ends are projected forward. The rear end portion of the link member 23 is rotatably connected to the lower end portion of the backrest 10 so that the backrest 10 can rotate between the standing position and the rearward tilt position.

  As shown in FIG. 7, the front end portions of both side walls 23 b of the link member 23 are pivotally attached to the protrusion 19 on the upper surface of the central portion of the support base 5 so as to be rotatable by the base shaft 15 common to the leaf spring 18 described above. ing.

  As shown in FIGS. 5 and 7, most of the gas spring 17 described above is accommodated in the accommodating recess 24 of the link member 23, and the front end portion of the gas spring 17 is the leaf spring 18 and the accommodating recess 24. A pivot 15 is pivotally attached to a base shaft 15 common to the link member 23. As described above, when the gas spring 17 is accommodated in the accommodating recess 24 of the link member 23, the gas spring 17 can be compactly disposed in a limited space below the seat 6, and the gas spring 17 is conspicuous. The chair looks better because it disappears. The gas spring 17 can be assembled in advance to the link member 23 with the base shaft 15.

As shown in FIGS. 5 to 7, a pair of left and right compression coil springs 32, 32 as back biasing means are attached to the rear half of the housing recess 24 of the link member 23 as follows. .
As shown in the exploded perspective view of FIG. 10, a small diameter portion of a stepped disk-shaped washer 34 having a semicircular concave groove 33 facing the left-right direction on the front surface at the front end portion of the left and right compression coil springs 32. 34a is fitted.

  In both compression coil springs 32, a spring holding plate 35 that faces in the front-rear direction and has a mounting portion 35 a having a large vertical dimension at the rear part passes through a long hole 36 a of a washer 36 that contacts the rear end of the compression coil spring 32. And is loosely fitted from the rear. The washer 36 is prevented from moving backward by coming into contact with the upper and lower shoulder portions 35b, 35b of the attachment portion 35a. A guide long hole 37 in the front-rear direction is formed in the front portion of the spring holding plate 35.

  The front end of the spring holding plate 35 penetrates through a long hole 38 provided in the front washer 34 and protrudes forward. By inserting a connecting shaft 39 that faces the left and right of the guide long hole 37 at the protruding portion, The compression coil springs 32 are contracted between the front and rear washers 34, 36 in a state where a required initial compression force is applied. The semicircular concave groove 33 in the front washer 34 is fitted to the rear surface of the connecting shaft 39, and the washer 34 is prevented from rotating with respect to the connecting shaft 39.

The left and right connecting shafts 39 are inserted into the guide elongated holes 37 of the left and right spring holding plates 35, and both left and right ends of the connecting shaft 39 are provided on the opposing surfaces of the intermediate portions of the side walls 23 b and 23 b of the link member 23. Further, it is supported by being detachably fitted from above to U-shaped support grooves 40, 40 facing diagonally forward and downward opening upward.
Further, the mounting portions 35a, 35a of the left and right spring holding plates 35 are slidably fitted with the shaft holes 41 drilled in the rear end portions thereof into the long holes 29 of the side walls 23b of the link member 23. By being inserted into the connecting shaft 30, it is supported by the connecting shaft 30.

  Accordingly, the pair of left and right compression coil springs 32 are mounted on both sides of the partitioning recess 42 in the rear half of the link member 23 so as to prevent interference with each other. In addition, since the pair of left and right compression coil springs 32 can be incorporated in the link member 23 in advance together with the gas spring 17 described above and unitized, the assembly to the chair becomes efficient.

  In the non-use state shown in FIG. 2, the chair configured as described above is lifted upward by the seat biasing means 12, that is, the biasing force of the gas spring 17 and the pair of leaf springs 18. The seat 6 is located in a non-use position that is inclined rearward and upward, and the backrest 10 is in an upright position through the link member 23 by a biasing force of a pair of left and right compression coil springs 32. Is retained.

  When the seated person sits in this state, the seat 6 rotates downward against the urging force of the seat urging means 12 together with the backrest 10, and the rear end is pivotally attached to the lower end of the backrest 10. The linked link member 23 also rotates downward about the base shaft 15. When the link member 23 rotates downward, as shown in FIG. 6, the stopper portion 26 provided on the link member 23 comes into contact with the stopper portion 28 of the support base 5, thereby stopping the downward rotation of the link member 23. And in connection with this, since the maximum downward rotation amount of the backrest 10 and the seat 6 is regulated, the seat 6 is rotated to the use position shown in FIGS. 3 and 6 and is maintained at that position. When the downward rotation of the link member 23 is stopped, the lower surface of the rear half of the seat plate 7 in the seat 6 may be brought into contact with the upper surface of the latter half so that it stops at the use position. The seat 6 is stably maintained in the use position by the link member 23.

  While the seat 6 is rotated to the use position, the left and right compression coil springs 32 only rotate downward together with the link member 23, and no compression force acts on the compression coil springs 32. The backrest 10 is maintained in an upright state. At this time, the connecting shaft 30 is located at the upper end of the long hole 29 of the link member 23.

  In this way, the stopper portion 26 is brought into contact with the stopper portion 28 to restrict the maximum downward rotation amount of the link member 23, and the seat 6 is stopped at the use position, or the seat plate is placed on the upper surface of the rear half portion of the link member 23. When the seat 6 is stopped at the use position by bringing the lower surface of the seat 7 into contact with each other, the gas spring 17 does not need to be retracted to the maximum and used as a stopper for the seat 6. It is possible to prevent the load from being applied and improve the durability.

  In the use position shown in FIG. 3, when the seated person tilts the backrest 10 backward, as shown in FIG. 6, the connecting shaft 30 supported by the bearing piece 31 at the lower end of the connecting shaft 30 becomes the long hole 29 of the link member 23. 4, the backrest 10 rotates about the support shaft 11 to the rearward tilt position as shown in FIG. 4 while compressing the left and right compression coil springs 32. .

  When the seated person returns the back to the front, the backrest 10 is rotated forward about the support shaft 11 by the extension by the elastic restoring force of the compression coil spring 32 and returned to the original standing position. That is, the backrest 10 can be reclined within the range of the length of the long hole 29.

  When the seated person tries to stand up from the seating state shown in FIG. 3, the seat 6 rotates upward toward the non-use position by the synergistic action of the urging force of the gas spring 17 and the pair of leaf springs 18. Thus, the seated person can be assisted in standing up.

  As described above, in the chair of the above embodiment, the upper surface of the center portion of the support base 5 and the lower end portion of the backrest 10 are connected by the link member 23 that cannot be expanded and contracted, and the seat 6 rotates to the use position. In the meantime, the compression coil spring 32 accommodated in the link member 23 only rotates downward together with the link member 23 so that the compression force does not act on it, and the stopper portion 26 of the link member 23 When the downward rotation of the link member 23 and the seat 6 is stopped in contact with the stopper 28 of the support base 5 and the backrest 10 is tilted backward in this state, the compression coil spring 32 is effectively compressed. Has come to work. Therefore, when seated, the seat 6 is not subjected to excessive upward biasing force other than the seat biasing means 12, so that the downward rotation of the seat 6 is not felt heavy, and the seat 6 can be comfortably seated. be able to.

  The downward rotation restricting means for restricting the maximum downward rotation amount of the seat 6 and the link member 23, that is, the link member 23 that connects the stopper portion 26 and the stopper portion 28 to the upper surface of the support base 5 and the lower end portion of the backrest 10. Are provided on the upper surface and the front end portion of the support base 5 and the seat 6, the opposite surface between the support base 5 and the seat 6, the pivot 9 of the seat 6, the base shaft 15 of the seat biasing means 12, etc. There is no need to provide a separate stopper, and the structure thereof can be simplified, and there is no fear that a bending load acts on the pivot 9 or the like or wears it.

  Further, the stopper portion 26 and the stopper portion 28 are in contact with each other on the surface, and the surface pressure at the time of contact is reduced, so that the wear of the contact surfaces can be suppressed.

  Furthermore, since it is not necessary to degenerate the gas spring 17 to the maximum and use it as a stopper, the durability of the gas spring 17 can be improved.

  Since most of the gas spring 17 and the compression coil spring 32 are accommodated in the accommodating recess 24 of the link member 23, the appearance of the chair is good and the height when the seat 6 is in the use position is low. Can be set.

The present invention is not limited to the above embodiment.
In the above embodiment, the inexpensive compression coil spring 32 is used as the back biasing means, but a gas spring or the like without a lock function may be used instead.

DESCRIPTION OF SYMBOLS 1 Caster 2 Leg rod 3 Leg 4 Leg column 5 Support base 5a Concave 5b Fitting groove 6 Seat 7 Seat plate 8 Cushion material 9 Axis 10 Backrest 10a Extension part 11 Support shaft 12 Seat biasing means 13 Elastic expansion / contraction means 14 Elastic bending means 15 Base shaft 16 Shaft pin 17 Gas spring (seat biasing means)
18 leaf spring 18a upper mounting portion 18b upper piece 18c elastic bending portion 18d lower piece 18e lower mounting portion 19 convex portion 20 concave groove 21 presser fitting 22 screw 23 link member 23a bottom wall 23b side wall 23c front wall 23d rear wall 23e extending Portion 23f bent portion 24 accommodating recess 25 upward recess 25a inclined portion 25b downward projection 26 stoppered portion (downward turning restricting means)
27 Upward convex portion 28 Stopper portion (downward turning restricting means)
29 long hole 30 connecting shaft 31 bearing piece 32 compression coil spring (back biasing means)
33 concave groove 34 washer 34a small diameter portion 35 spring holding plate 35a mounting portion 35b shoulder 36 washer 36a long hole 37 guide long hole 38 long hole 39 connecting shaft 40 support groove 41 shaft hole 42 partition piece

Claims (7)

A base supported by legs,
A seat pivotally attached to the support base with a pivot that faces in the left-right direction, and a rear portion that is rotatable up and down between a non-use position and a use position;
A seat biasing means provided on the support base and biasing a rear portion upward from the pivot in the seat;
A backrest pivotally attached to a rear portion of the seat with a support shaft facing in the left-right direction and capable of rotating between a standing position and a rearward tilt position;
In a chair comprising back biasing means for biasing the backrest to an upright position,
The backrest is rotated between a standing position and a rearward tilt position by a link member facing the front-rear direction of a portion of the support base that is behind the pivot shaft and a portion of the backrest that is lower than the support shaft. While connecting with as much play as possible, the support base is provided with a downward rotation restricting means for restricting the downward rotation amount of the link member, and the back biasing means includes the link member and the lower part of the backrest. A chair characterized in that the backrest is urged toward the standing position by being provided between the two.   The link member is provided with an arc-shaped elongated hole centered on the back support shaft, and a connecting shaft facing in the left-right direction is slidably fitted into the elongated hole so that the rear end portion of the link member is The back end of the backrest is connected to the lower end of the backrest with play sufficient to allow the backrest to rotate between the standing position and the rearward tilt position, and the rear end of the link member and the rear end of the back biasing means are connected to each other. The chair according to claim 1, wherein the chair is connected to a lower portion of the backrest with a common connecting shaft.   The link member is shaped like a case having an accommodation recess that opens upward, and long holes are provided in both side walls of the link member made into this case shape, and the rear end portion of the back biasing means accommodated in the accommodation recess is The chair according to claim 2, wherein the chair is supported by an intermediate portion of a connecting shaft inserted through both elongated holes.   4. The chair according to claim 3, wherein the seat biasing means and the back biasing means are accommodated and assembled in the receiving recess of the link member so that the link member, the seat biasing means and the back biasing means are unitized. .   The seat urging means and the back urging means are respectively housed in the front and rear portions in the receiving recess of the link member so that the positions of the seat urging means and the seat urging means face obliquely rearward and upward. The chair according to claim 3 or 4.   The chair according to any one of claims 3 to 5, wherein the back urging means is composed of a pair of left and right, and the pair of back urging means is accommodated in an accommodation recess of the link member.   The chair according to any one of claims 1 to 6, wherein the front end portion of the back biasing means and the front end portion of the link member are pivotally attached to a support base with a common axis facing in the left-right direction.

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