JP5632204B2 - Chair - Google Patents

Description

  The present invention relates to a chair that can be tilted backward by pivotally attaching a lower part of the backrest to a rear portion of a seat.

  As a conventional chair of this type, for example, there is a chair in which both sides of the lower end of the backrest are pivotally attached to a seat with hinges (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 48-063856

  The conventional chair described above is provided with fitting holes in both the seat and the backrest, and by inserting the pivots into both fitting holes while maintaining the positions of these fitting holes, This requires a work to combine the back and the backrest, which causes a problem that work efficiency is poor.

  The present invention has been made in view of the above problems, and provides a chair that is easy to combine the seat and the backrest, can improve work efficiency, has a simple structure, and can be manufactured at low cost. The purpose is to do.

According to the present invention, the above problem is solved as follows.
(1) In a chair that can be tilted backward by pivoting the side part of the backrest to the rear part of the seat, the protrusion projecting on the inner surface of the forward piece provided at the lower part on both sides of the backrest The shaft is fitted into a fitting hole facing in the left-right direction provided on both side surfaces of the seat plate in the seat, and a retaining member is fixed to the inner end of each projecting shaft inside the seat plate. Thus, each projecting shaft is prevented from coming off from the fitting hole, and a seating member provided on the seat plate is positioned between the both retaining members so that the both retaining members are not exposed.

  With such a configuration, the left and right sides are expanded while elastically deforming both sides of the backrest, and the projecting shafts projecting from the inner surface are fitted to the fitting holes on both sides of the seat plate, The seat and the backrest can be pivotally coupled by simply fitting them to each other and attaching the retaining member to the inner end of each projecting shaft, and the working efficiency can be greatly improved. Further, since the retaining member is concealed by the seating member, it is not exposed to the outside, and the appearance of the chair can be improved.

(2) In a chair in which the backrest can be tilted backward by pivotally attaching the side of the backrest to the rear portion of the seat, the projecting shafts protruding from the inner side surfaces on both sides of the backrest are Fitting each projecting shaft by fitting it in the left and right mating holes provided on both sides of the plate, and fixing the retaining member to the inner end of each projecting shaft inside the seat plate By retaining a seating member provided on the seat plate between the both retaining members, the both retaining members are prevented from being exposed, and further, on the side portion of the seat plate. Recessed stepped portions that are recessed inward from each other are provided, a fitting hole is provided in a side surface facing the left-right direction of the recessed stepped portion, a protruding shaft is fitted into the fitting hole, and a backrest is provided. The side portion is fitted to the recessed step portion so as to be rotatable about the protruding shaft.

With such a configuration, in addition to the effects described in paragraph 0007, the side portion of the backrest can be accommodated in the recessed step portion provided on the side portion of the seat plate, and the side portion protrudes outward of the seat plate. The appearance of the chair can be improved.

(3) In the above item (2), the front edge of the side portion of the backrest and the front surface facing the rear of the recessed stepped portion facing the front edge are formed in an arc shape having substantially the same radius of curvature.

  With such a configuration, when the backrest is rotated, the gap between the front surface of the recessed step portion of the seat plate and the front edge of the side portion of the backrest facing this is prevented from expanding. it can.

(4) In the above item (2) or (3), when an outward projecting part is provided on the outer periphery of the base part of the projecting shaft and the backrest is rotated to the rotation limit position in the vicinity of the fitting hole in the recessed stepped part. In addition, a stopper with which the outward projection comes into contact is provided on the side surface of the recessed step.

  With such a configuration, it is possible to prevent the backrest from rotating excessively. In addition, since the stopper is provided on the outer surface of the seat plate, the stopper can be prevented from interfering with the work when the retaining member is fixed from the inner side of the seat plate to the end surface of the protruding shaft. The appearance is good because it is not exposed to the outside.

(5) In the above item (4), the stopper has an arc shape centered on the fitting hole, and faces the tangential direction of the arc to the end of the stopper where the outward projecting portion on the projecting shaft side abuts. Reinforcing ribs are provided.

  With such a configuration, since the impact load when the outward projection comes into contact with the stopper acts in the same direction as the reinforcing rib, the stopper load bearing performance is enhanced and the stopper can be prevented from being damaged.

  According to the present invention, the efficiency of the joining operation between the seat and the backrest is greatly improved. In addition, the structure is simple, the joint between the seat and the backrest can be prevented from being exposed to the outside, and the appearance can be improved.

It is a front view of 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 of a use state. Similarly, it is a side view when the backrest is tilted backward in the use state. Similarly, it is a center vertical side view which shows the center part in the chair of a non-use state, abbreviate | omitting the cushion material of the seat. Similarly, it is the partially exploded perspective view which looked at the member with which the support base and the support base were mounted from diagonally upward. It is a top view of a leaf | plate spring. It is a side view of a leaf | plate spring. It is a top view of a compression spring. It is a side view of a compression spring. It is the XI-XI sectional view taken on the line of FIG. It is a disassembled perspective view of a backrest. It is an enlarged perspective view of the principal part which shows the connection structure of a back frame and a seat board. It is a perspective view which shows the recessed part of a seat board, a fitting hole, and a stopper. It is the XV-XV sectional view taken on the line of FIG. It is a vertical side view which shows the positional relationship of a back frame and a seat board in a non-use state. It is a vertical stage side view which shows the positional relationship of a back frame and a seat board when backrest is inclined backward. It is a disassembled perspective view which shows the fitting recessed part and fitting member of an intermediate | middle connection rod. It is the XIX-XIX line expanded sectional view of FIG. It is the XX-XX line expanded sectional view of FIG. It is the XXI-XXI line expanded sectional view of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIGS. 1 to 4, the chair includes a leg body 3 having five leg rods 2 each having a caster 1 at a distal end. 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.

  As shown in FIG. 6, the support base 5 has a shallow dish shape with 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 is composed of a synthetic resin seat plate 7 and a cushion material 8 as a seating member attached to the upper surface of the seat plate 6. As shown in FIG. 2, the pivot 9 is pivoted to the non-use position inclined backward and upward as shown in FIG. 2 and the use position inclined horizontally or rearward downward as shown in FIG. 3. It can be rotated around the center. The rotation range is preferably about 15 degrees.

The seat 6 is constantly urged upward toward the non-use position by an urging means 12 described later.
As shown in FIG. 2, when the seat 6 is in the non-use position, the initial contact portion P that first contacts when the seated person tries to sit is positioned behind the center line O of the pedestal 4. It is.
When the seat 6 is in the use position, the initial abutment portion P matches the stable support portion that stably supports the vicinity of the seat bone portion, which is the buttocks, when the seated person sits in an appropriate sitting posture. It is preferable to define it.

When the initial abutting portion P is positioned behind the center line O of the pedestal 4 when the seat 6 is in the non-use position, the seated person sits on the seat 6 in the non-use position. At this time, when the seated person's buttocks abuts against the initial abutting portion P of the seat 6, there is no possibility that the inconvenience of the chair moving backward occurs.
In addition, after the seated person's buttocks abuts against the initial abutting portion P of the seat 6, the seat 6 rotates together with the seated person's buttocks against the biasing force of the biasing means 12 to the use position. The user's buttocks are guided to the stable support point, so that the seated person can quickly take an appropriate seating posture and the seater's load is applied to the rear of the pedestal 4, so that the seat 6 is seated by the rear part of the seat 6. A person's buttocks can be supported stably.

  The larger the rearward upward tilt angle of the seat 6 when it is in the non-use position, the more the initial contact part P moves forward and approaches the pedestal 4 or the front thereof. As described above, the seat 6 is rearwardly upward when the initial contact portion P is located at the non-use position so that it is located behind the center line O of the pedestal 4. It is preferable to limit the inclination angle.

  On the both sides of the rear part of the seat plate 7, the front part of the extending part 10 a that faces the front side from the lower side of the backrest 10 is located behind the center line O of the pedestal 4, and is supported in the left-right direction. As shown in FIGS. 2 and 3, the backrest 10 is pivotally attached to each other with a shaft 11, and is rotated about the support shaft 11 between a standing position facing upward and a rearward tilt position as shown in FIG. It is possible to move. Note that the specific structure of the backrest 10 and the pivotally attached portion is not directly related to the present invention, and thus detailed illustration and description thereof will be omitted.

The support base 5 is provided with a biasing means 12 that biases the rear portion of the seat 6 upward.
The 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 both sides of the elastic expansion / contraction means 13. The front upper end is fixed to the lower surface, the middle portion is elastically bent into a U-shape opening forward in a side view, and the front lower end is fixed at a position below the pivot 9 in the support base 5. A pair of left and right elastic bending means 14 and 14 are provided.

In this example, as shown in FIGS. 2, 5, and 6, the elastic expansion / contraction means 13 is pivotally attached to the support base 5 with a shaft 15 in the left-right direction, and the rear end is on the lower surface of the seat 6. The gas spring 17 has a locking function and is pivotally attached to a middle portion in the front-rear direction with a shaft pin 16 in the left-right direction. However, a gas spring having a lock function, a compression coil spring, an oil damper, an air damper, or the like may be used.
In the case of a gas spring having a locking function, it is preferable to provide the unlocking operation means on a part of an armrest (not shown), for example.

  In this example, each of the left and right elastic bending means 14 is, as shown in FIGS. 5 to 8, a rectangular upper mounting portion which is long in the front-rear direction and is fixed to the front portions on both sides of the lower surface of the seat 6 by a set screw or the like. 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 made of synthetic resin having a lower piece 18d extending from the lower end to the front or the front lower side, and a lower attachment portion 18e provided at the front end of the lower piece 18d and attached to the support base 5 It consists of 18 and 18. Each leaf spring 18 may be made of metal.

  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 and a push rod 23 described later, and for accommodating them collectively in a narrow space below the seat 6.

  Further, as shown in FIG. 6, 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 so, the rear part of the seat 6 can be stably supported.

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

  The shaft 15 is fixed to the front upper surface of the support base 5 as follows. That is, as shown in FIGS. 5 and 6, a recess 5a facing in the left-right direction is provided on the bottom surface of the front portion of the support base 5 below the pivot 9, and a plurality of protrusions arranged in the left-right direction in the recess 5a. 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. By fixing with the screws 22, 22, the 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 biasing 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 provided with a left and right balance. The seat 6 can be lifted well and can support the seat 6 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 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, and the durability of the leaf spring 18 can be improved and the reaction force of the leaf spring 18 can be increased. Can be made.
As a result, the reaction force of the leaf spring 18 increases as the seat 6 is rotated downward.

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 connected by an elastically extendable push rod 23 that faces in the front-rear direction.
When the seat 6 is pivoted downward from the non-use position to the use position, the lower end portion of the backrest 10 is pushed backward by the pushing rod 23 so that the backrest 10 is maintained in an upright state. As the heel 23 is elastically contracted, the backrest 10 can be inclined backward as shown in FIG.

As shown in FIGS. 6 and 9 to 11, the push rod 23 is pivotally attached to the support base 5 by the left and right shafts 15 on both sides of the gas spring 17 whose front end portion is the elastic expansion / contraction means 13. A pair of left and right leg pieces 23a, 23a that are hard and inflexible, and a pair of left and right elastic flexures 23b, 23b that are connected to the rear ends of both leg pieces 23a, 23a and face the rear of a circular cross section; A rigid and non-flexible connecting piece 23c that connects the rear ends of both foot pieces 23a and 23a below the gas spring 17 and a hard and non-flexible that connects the rear ends of both elastic flexures 23b and 23b. It is comprised by the compression spring which has the flexible connection part 23d.
The central portion of the connecting piece 23 c is recessed downward so as not to interfere with the lower surface of the gas spring 17. The push rod 23 is preferably integrally formed of, for example, a polyamide-based hard synthetic resin.

A left and right shaft hole 24 that is inserted through the shaft 15 is formed at the front end of the left and right foot pieces 23a, 23a.
The connecting portion 23d that is wide in the left-right direction at the rear end is also provided with a shaft hole 25 that faces in the left-right direction. The shaft hole 25 is connected to the connecting portion 23d in the left-right direction on the front surface of the lower end of the backrest 10. A shaft pin 27 for pivotally mounting on a pair of left and right bearing pieces 26 projecting forward at the center is inserted (see FIG. 5).

The left and right elastic flexures 23b, 23b are curved in a generally convex arc shape outward in the left-right direction of the chair, and the cross-sectional shape is substantially circular.
The left and right elastic bent portions 23b and 23b of the push rod 23, the connecting pieces 23c connecting the respective end portions, and the connecting portion 23d are formed in a closed loop shape having a substantially circular shape in plan view.

  The push rod 23 is arranged so that both elastic bending portions 23b and 23b are arranged on the left and right sides of the chair, and is connected to the support base 5 and the backrest 10 so as to be elastic when the backrest 10 is tilted backward. As shown by a two-dot chain line in FIG. 9, the bent portions 23b and 23b are elastically bent so as to swell outward in the left-right direction. The left and right elastic bent portions 23b and 23b are curved in an inwardly arcuate shape opposite to the above, and both elastic bent portions 23b are elastically bent inward in the left-right direction of the chair. Sometimes it does.

  As shown in FIG. 10, the middle part of the left and right elastic flexures 23b, 23b is slightly curved downward in a side view, and a compressive load in the front-rear direction is applied to both elastic flexures 23b. In this case, the intermediate portion can be elastically deformed in the lower direction perpendicular to the plane including both elastic flexures 23b. The elastic bending portion 23b may be curved in an upward arc shape, contrary to the above.

  When the compression spring used as the push rod 23 is subjected to a longitudinal compressive force between the front and rear ends, both elastic bending portions 23b and 23b are elastically bent in a direction perpendicular to the compression direction. Even if one of the members (the support base 5 and the backrest 10) moves relative to the backrest 10 as described above, both the elastic bending portions 23b and 23b are effectively elastically bent. Thus, the spring force can be exerted, and the versatility becomes high.

In addition, since the structure is simple compared to a cylinder-type compression spring such as a gas spring, it is possible to provide an inexpensive and lightweight compression spring.
Further, the elastic bent portions 23b and 23b and the hard connecting pieces 23c and 23d before and after connecting the end portions thereof are circular or non-circular in plan view (when elastically bending inward with respect to each other). Etc.), the elastic bending portion 23b can be effectively elastically bent to obtain a large spring force, and sufficient strength and durability against repeated loads can be obtained. Can have. Moreover, since each elastic bending portion 23b has a substantially circular cross section, it can be effectively elastically deformed in any direction.

  Since both elastic flexures 23b can be elastically deformed in a direction perpendicular to the plane including them, the relative movement amount between the front and rear ends becomes large, and the backrest 10 is greatly inclined backward. Can do.

  When the compression spring as described above is mounted as the push rod 23 between the support base 5 and the backrest 10 in the chair of the above embodiment, when the backrest 10 is tilted backward, the left and right elastic flexures 23b and 23b are elastically bent in the left-right direction, so that it is not necessary to provide a vertical bending space for the push rod 23 between the support base 5 and the seat 6, and when the seat 6 is in the use position. Can be set low.

  In addition, the compression spring as the push rod 23 is simple and inexpensive compared to a back biasing means such as a gas spring or a rubber torsion spring, so that the chair can be reduced in weight, Cost reduction can be achieved.

  Further, the push rod 23 has a pair of left and right foot pieces 23a at the front portion and a connecting portion 23d having a wide width at the rear portion in the left-right direction, and a shaft 15 and a shaft pin 27 in the left-right direction, respectively. Since it is pivotally attached to the flange 10, it can be elastically deformed stably.

  The front end portions of the foot pieces 23a, 23a of the push rod 23 are connected to the front end portion of the gas spring 17 as the elastic expansion / contraction means 13 and the lower attachment portions 18e, 18e of the left and right leaf springs 18, 18 as the elastic bending means 14. In addition, since it is pivotally attached to the support base 5 with a common shaft 15 facing in the left-right direction, not only can the structure be further simplified, but also the elastic expansion / contraction means 13, the elastic bending means 14 and the push rod to the support base 5. The pivoting operation with 23 can be further simplified.

  Next, a connection structure between the backrest 10 and the seat 6 will be described. As shown in FIG. 12, the backrest 10 includes a closed loop back frame 29 and a tension member 30 stretched on a surface 29 a of the back frame 29. The lower frame portion 31 of the back frame 29 is provided with forward pieces 32 that form the extending portions 10a on both the left and right sides thereof by being curved so as to be concave forward in plan view.

A relatively short projecting shaft 34 facing inward of the back frame 29 is provided on the inner surface of each forward piece 32 via a pedestal 33, and this constitutes the support shaft 11. The protruding shaft 34 has a smaller diameter than the pedestal 33. As shown in FIG. 13, a cross-shaped reinforcing rib 11 a and two screw holes 11 b and 11 b are provided in the internal space of the projecting shaft 34. An outward projection 35 is provided on the outer peripheral surface of the pedestal 33 near the tip surface, and a flat surface 35 a extending in the center direction of the pedestal 33 is provided at one end of the outward projection 35 in the circumferential direction.

  In addition, a recessed step 36 that is recessed inward from each other is provided on the rear side of the seat plate 7. A thick portion 37 is provided in a portion inside the side surface 36 a facing the left-right direction of the recessed step portion 36 of the seat plate 7, and a fitting hole 38 facing the left-right direction is provided in the thick portion 37. . The front edge 32a of the forward piece 32 of the back frame 29 and the front surface 36b (see FIG. 14) facing rearward in the recessed stepped portion 36 of the seat plate 7 are curved with substantially the same radius of curvature.

  As shown in FIG. 14, an arcuate stopper 39 that is concentric with the fitting hole 38 and has a larger diameter than the fitting hole 38 is provided on the side surface 36 a of the recessed step portion 36. One end of the stopper 39 is provided with a flat surface 39 a facing the center direction of the fitting hole 38 and a reinforcing rib 39 b extending in a direction substantially perpendicular to the flat surface 39 a, that is, a tangential direction of the stopper 39.

  When connecting the backrest 10 to the seat 6, as shown in FIG. 13, a flanged sleeve 40 is fitted on the outer periphery of the projecting shaft 34 so that the flange 40 a is outside, and the forward piece 32 of the backrest 10 is inserted. Is inserted into the recessed step 36 of the seat plate 7. Then, as shown in FIG. 15, the projecting shaft 34 is fitted into the fitting hole 38 together with the flanged sleeve 40 from the outside of the seat plate 7.

  Next, a disc-shaped retaining member 41 having a larger diameter than the fitting hole 38 is secured to the end surface 34 c of the projecting shaft 34 from the inside of the seat plate 7 with a screw 42. At this time, the sliding member 43 is preferably sandwiched between the thick portion 37 and the retaining member 41. As a result, the retaining member 41 is pivotably locked to the thick portion 37 of the seat plate 7.

  When the forward facing piece 32 of the back frame 29 is inserted into the recessed step portion 36 of the seat plate 7, as shown in FIG. 16, the front edge 32a of the forward piece 32 and the front surface 36b of the recessed step portion 36 Are aligned with a slight gap.

  When no back load is applied to the backrest 10, as shown in FIG. 16, a flat surface 35 a of the outward projection 35 provided on the base 33 of the projecting shaft 34 of the back frame 29 is provided on the seat plate 7. The stopper 39 is spaced from the flat surface 39a.

When a backward load is applied to the backrest 10 by a seated person, the back frame 29 rotates backward about the protruding shaft 34 as shown in FIG. When the back frame 29 is rotated to the maximum allowable rotation angle, the flat surface 35a of the outward projection 35 of the back frame 29 comes into contact with the flat surface 39a of the stopper 39 of the seat plate 7, and the backrest 10 is rotated. Be stopped.
The impact load when the outward projection 35 abuts against the stopper 39 acts in the same direction as the reinforcing rib 39b, so that the stopper load bearing performance is enhanced and the stopper 39 can be prevented from being damaged.

  After the back frame 29 and the seat plate 7 are joined, the cushion material 8 is covered on the seat plate 7 so as to cover the joint portion between the protruding shaft 34 and the fitting hole 38 (see FIG. 1).

  Next, the tension structure of the tension member 30 with respect to the back frame 29 will be described. As shown in FIG. 12, an intermediate connecting rod 45 is provided between the left and right side frame portions 44 in the closed loop back frame 29 of the backrest 10 so as to face in the left-right direction. The intermediate connecting rod 45 is positioned between the upper frame portion 46 and the lower frame portion 31 of the back frame 29 at a position corresponding to the waist of the seated person, in the present embodiment, at a position relatively close to the lower frame portion 31. Is provided. The lower frame portion 31 has a large vertical width and is relatively thin.

 The intermediate connecting rod 45 is connected to the inside of the left and right side frame portions 44 of the back frame 29 and is curved between the left and right connecting portions 47, 47 that are curved obliquely downward and rearward. It comprises a straight portion 48 provided. The straight portion 48 protrudes rearward from the left and right side frame portions 41, 41.

  A fitting recess 49 is provided on the surface 47a of the left and right connecting portions 47, 47 along the curved surface. As shown in FIG. 18, positioning ribs 50 and screw holes 51 facing in the left-right direction are provided in the fitting recess 49.

  A fitting member 52 is fitted in the fitting recess 49. A screw mounting hole 53 is provided at one end of the fitting member 52. Further, a positioning groove 54 that is fitted to the positioning rib 50 of the fitting recess 49 is provided on the bottom surface 52 a of the fitting member 52.

  As shown in FIG. 19, the left and right side frame portions 44 are formed so that the cross-sectional shape is elongated in the front-rear direction and gradually becomes thicker from the rear end portion toward the front end portion. On the outer peripheral surface 44b near the surface 44a in the portion above the intermediate connecting rod 45 of the left and right side frame portions 44, a concave groove 55 facing the longitudinal direction is provided so as to open outward. The concave groove 55 is also provided on the outer peripheral surface 46 b near the surface 46 a of the upper frame portion 46. The opening of the edge in the longitudinal direction of the concave groove 55 in the left and right side frame portions 44 opens toward the fitting concave portion 49 of the connecting portion 48 in the intermediate connecting rod 45 as shown in FIG.

  As shown in FIG. 20, a concave groove 56 is provided on the outer peripheral surface 52c near the surface 52b (see FIG. 18) of the fitting member 52 fitted in the fitting concave portion 49 so as to open to the outer peripheral side. ing. The concave groove 56 of the fitting member 52 is continuous with the concave groove 55 (see FIG. 18) of the left and right side frame portions 44 opened in the fitting concave portion 49.

  As shown in FIG. 21, the straight portion 48 of the intermediate connecting rod 45 has a cross-sectional shape that is elongated in the front-rear direction. On the outer peripheral surface 48b side of the straight portion 48 near the surface 48a, a ridge 48c facing in the longitudinal direction and projecting downward is provided. A concave groove 57 facing the longitudinal direction is provided on the back surface side of the protrusion 48c. The concave groove 57 extends to the vicinity of the boundary between the linear portion 48 and the connecting portion 47.

  As shown in FIG. 12, the upholstery material 30 of the backrest 10 is formed to be stretchable by a mesh material. The peripheral edge portion 30a of the tension member 30 is formed in a bag shape, and an edge member 58 (see FIG. 19) is inserted and sewn therein. The edge member 58 is formed in an elongated flat plate shape from a synthetic resin having elasticity.

  When the tension member 30 is stretched on the surface side of the back frame 29, as shown in FIG. 20, the fitting member 52 is fitted into the fitting recess 49 of the intermediate connecting rod 45, and each is fastened with screws.

  Next, the upholstery material 30 in which the edge member 58 is sewn to the peripheral edge portion 30a is attached to the surface 44a side of the left and right side frame portions 44 above the intermediate coupling bar 45 of the back frame 29 and the surface 46a side of the upper frame portion 46. Then, as shown by an imaginary line in FIG. 19, the edge member 58 of the tension member 30 is pulled toward the outer peripheral surface 44b of the side frame portion 44 with an appropriate force. Next, as shown by a solid line in FIG. 19, the edge member 58 is inserted into the concave groove 55. Similarly, the edge member 58 at the peripheral edge 30 a of the tension member 30 is inserted into the groove 55 of the upper frame portion 46 and the groove 56 of the fitting member 52. Further, since the concave groove 57 of the straight portion 48 of the intermediate connecting rod 45 opens rearward, after the lower portion of the tension member 30 is pulled out rearward along the lower surface of the intermediate connecting rod 45, the lower edge The material 58 is inserted from behind the concave groove 57.

  Thereby, the edge member 58 is pulled to the surface side of the side frame portion 44 and the upper frame portion 46 above the intermediate coupling rod 45 of the back frame 29 by the tension of the tension member 30, and the edge member 58 is recessed into the grooves 55 and 56. Is engaged. As a result, the tension member 30 is maintained in a state of being stretched on the respective surface sides of the upper frame portion 46, the left and right side frame portions 44, and the intermediate connecting rod 45 in the back frame 29. Further, since the tension member 30 is not stretched between the intermediate connecting rod 45 and the lower frame portion 31, as shown in FIG. 1, the backrest 10 and the seat 6 communicate with each other in the front-rear direction. A gap 59 is formed.

  In the non-use state shown in FIG. 2, the chair configured as described above is lifted upward by the urging force of the urging means 12, and the seat 6 is positioned at a non-use position where the seat 6 inclines rearward upward. The backrest 10 is held in an upright position substantially facing upward by the extension of the push rod 23.

  In this state, when the seated person tries to sit down, the seated person's buttocks first come into contact with the initial contact part P of the seat 6 as described above, and the seat 6 together with the seated person's buttocks is attached to the biasing means 12. It is rotated to the use position shown in FIG. 3 against the force, and the seat occupant's buttocks are guided to the stable support point, so that the seat occupant can quickly take an appropriate seating posture.

  When the seated person leans back on the backrest 10 and tilts the back backward from the sitting state shown in FIG. 3, the backrest 10 is elastically contracted by the push rod 23, and the support shaft 11 is centered. It is rotated to a rearward tilt position as shown in FIG. At the initial stage of the elastic contraction of the push rod 23, the hard connecting portion 23d is pushed forward by the shaft pin 27, and at this time, the left and right elastic bent portions 23b, 23b are slightly connected to the connecting portion 23d. While being twisted in the vertical direction, the entire elastic bending portions 23b, 23b are elastically bent so as to bulge outward in the left-right direction as shown by a two-dot chain line in FIG. 9, and slightly meander in the vertical direction. It is elastically deformed.

  When the seated person returns his / her 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 push rod 23 and returned to the original standing position.

  When the seated person tries to stand up from the seating state shown in FIG. 3, the seat 6 is attached so as to rotate upward toward the non-use position by the synergistic action of the elastic expansion / contraction means 13 and the elastic bending means 14. The seated person can be assisted in standing up.

  Further, according to this chair, the left and right forward pieces 32, 32 of the backrest 10 are elastically deformed so as to expand each other, and the backrest 10 is fitted into the fitting hole 38 on the rear side portion of the seat plate 7. The projecting shaft 34 of the forward piece 32 is fitted from the outside of the seat plate 7, and the retaining member 41 is fixed to the end surface 34 c of the projecting shaft 34 from the inside of the seat plate 7. Can be coupled with each other in a rotatable manner, so that the working efficiency can be greatly improved. Moreover, since the engaging part of the seat 6 and the backrest 10 is covered with the cushioning material 8 which is a seating member, the external appearance can be maintained satisfactorily.

The present invention is not limited to the above-described embodiment, and can be implemented in various modified forms without departing from the scope of the claims.
For example, instead of the cushion material 8, a hard seating member may be attached to the seat plate 7.

DESCRIPTION OF SYMBOLS 1 Caster 2 Leg rod 3 Leg 4 Leg column 5 Support base 5a Recess 6 Seat 7 Seat plate 8 Cushion material (sitting member)
9 pivot 10 backrest 10a extending portion 11 support shaft 11a reinforcing rib 11b screw hole 12 biasing means 13 elastic expansion / contraction means 14 elastic bending means 15 shaft 16 shaft pin 17 gas spring 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 Pushing rod (compression spring)
23a foot piece (hard part)
23b elastic bending part 23c connection piece (hard part)
23d connecting part (hard part)
24, 25 Shaft hole 26 Bearing piece 27 Shaft pin 29 Frame 29a Surface 30 Upholstery material 31 Lower frame portion 32 Front piece 32a Front edge 33 Base 34 Projection shaft 34c End surface 35 Outward projection 35a Flat surface 36 Recessed step portion 36a Side surface 36b Front surface 37 Thick wall portion 38 Fitting hole 39 Stopper 39a Flat surface 39b Reinforcement rib 40 Ribbed sleeve 40a 鍔 41 Detachment member 42 Screw 43 Sliding member 44 Side frame portion 45 Intermediate connecting rod 45a Surface 45b Outer peripheral surface 46 Upper frame portion 46a Surface 46b outer peripheral surface 47 Connecting portion 47a Surface 48 Linear portion 48a Surface 48b Outer peripheral surface 48c Projection 49 Fitting recess 50 Positioning rib 51 Screw hole 52 Fitting member 52a Bottom surface 52b Surface 52c Outer peripheral surface 53 Hole 54 Groove 55 Groove 56 Groove 57 Groove 58 Edge material 59 Clearance

Claims (5)

In a chair that allows the back to be tilted backwards by pivotally attaching the side of the back to the back of the seat,
A projecting shaft projecting from the inner side surface of the forward piece provided at the lower part on both sides of the backrest is fitted into a fitting hole facing in the left-right direction provided on both side surfaces of the seat plate in the seat, Inwardly, by fixing a retaining member to the inner end of each projecting shaft, each projecting shaft is retained from the fitting hole, and a seat provided on the seat plate between the both retaining members. A chair characterized in that the both retaining members are not exposed by positioning a member. In a chair that allows the back to be tilted backwards by pivotally attaching the side of the back to the back of the seat,
The projecting shafts projecting on the inner side surfaces on both sides of the backrest are fitted into the fitting holes facing in the left-right direction provided on the both side surfaces of the seat plate in the seat. By fixing a retaining member to the inner end of the shaft, each projecting shaft is prevented from slipping out of the fitting hole, and a seating member provided on the seat plate is positioned between the both retaining members, The both retaining members are prevented from being exposed, and a recessed stepped portion is formed in the side portion of the seat plate so as to be recessed inward from each other. The recessed stepped portion is fitted to a side surface facing in the left-right direction. A chair characterized in that a hole is provided, a protruding shaft is fitted into the fitting hole, and a side portion of a backrest is fitted to the recessed step portion so as to be rotatable about the protruding shaft.   The chair according to claim 2, wherein the front edge of the backrest side portion and the front surface facing the rear of the recessed step portion facing the front edge are formed in an arc shape having substantially the same radius of curvature.   An outward protrusion is provided on the outer periphery of the base of the protrusion shaft, and a stopper that contacts the outward protrusion when the backrest rotates to the rotation limit position is recessed in the vicinity of the fitting hole in the recessed step. The chair according to claim 2 or 3 provided on a side surface of the stepped portion.   5. The stopper according to claim 4, wherein the stopper is formed in an arc shape centering on the fitting hole, and a reinforcing rib facing the tangential direction of the arc is provided at an end portion of the stopper where the outward projecting portion on the projecting shaft side abuts. Chair.

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