JPH0295305A - Chair having seat back - Google Patents

Abstract

PURPOSE:To improve the durability of a spring member, and simultaneously, to obtain smooth flexible repulsive action to a seat back by interveningly providing a spring member to elastically energize a back supporting lever to the front side between the edge of a seat side bracket and the edge of a back side bracket provided on the back supporting lever. CONSTITUTION:To a leg post 2 projectingly provided from a leg blade 1 to an upper side, a seat receiving member 3 is connected, L-shaped fittings 7 are fitted to both edges of a bracket 4 rigidly mounted to a top board 3a, respectively, and a pin 8 is projectingly provided from the outer side surface of a bent part 7a towards an external side. The upper edge of a back supporting lever 9 to be turnably pivot-supported to the seat receiving member 3 is extended, L-shaped fittings 12 are fitted to both edges of a bracket 10 for locking a seat back 11, and a pin 13 is projectingly provided from the outer side surface towards the external side. With the pins 8 and 13, both edges of a spring member 14, in which coil springs are elastically provided turnably, respectively, are engaged. Even when the member 14 is made somewhat large, the fitting can be executed without inconvenience, the degree of a fatigue due to a repeated utilization is made small, and thereby, the durability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a chair with a backrest whose backrest can be tilted rearward.

[Prior Art] Conventionally, as this type of chair, for example, a seat is disposed via a seat support member on a support base supported by a pillar, and a back support rod is attached to the support base in a predetermined manner. It is known that the chair is pivoted so that it can be tilted rearward from a standard standing position, and a backrest is provided on the back support rod.

Only 1. In such a chair, the support MO
A spring is built in B, and the spring elastically biases the back support rod so that it can self-return to the standard standing position. Therefore, the spring bears the elastic supporting force when the user leans back against the backrest.

[Problems to be Solved by the Invention] However, since there is a certain limit to the size of the support base disposed on the underside of the seat, it is difficult to accommodate a large spring therein. In particular, in the case where the support base is provided with a mechanism for moving the seat in conjunction with the backward tilting movement of the backrest, a mechanism for adjusting the height of the pillar, etc., the space for installing the spring is narrow. It tends to be limited in scope. For this reason, it is necessary to use small springs whose elastic repulsion changes greatly with just a slight displacement, which tends to cause problems with the durability of the springs, and also provides smooth elastic repulsion with plenty of room in the backrest. There is a problem in that it is difficult to impart effects.

The present invention aims to solve the above problems.

[Means for Solving the Problems] In order to achieve the above object, the present invention takes the following measures.

That is, in the chair with a backrest according to the present invention, there is a gap between the end of the birth control bracket provided on the seat support member that supports the seat and the end of the backside bracket provided on the back support rod that can tilt in the front-rear direction. It is characterized by interposing a spring member that elastically urges the back support rod forward.

In order to give the spring member the function of an armrest, the spring member is made of a synthetic resin that has an upright part that rises from the production bracket and a horizontal part that extends forward from the dorsal bracket that are smoothly connected. It is preferable that the cross-sectional shape of this spring member is approximately C-shaped.

In the present invention, a seat support member is supported on a support base so as to be movable back and forth, and a back support rod is pivotally supported on the support base so that the seat support member can be tilted. If applied to a chair configured such that the receiving member can move forward with respect to the support base, its function can be particularly well exhibited.

[Function] When the backrest is tilted backward from the standard upright position, the distance between the backside bracket provided on the back support rod and the support bracket provided on the seat support member changes, and the distance between the backside bracket provided on the back support rod and the support bracket provided on the seat support member changes. The spring member is elastically displaced. Along with this, the elastic repulsive force of this spring member gradually increases, and a force in the direction of eliminating the displacement acts on the back support rod, urging the backrest toward the original standard standing position. As a result, the load is elastically supported at the rearward tilted position where the biasing force balances the load applied to the backrest.

Further, by providing a spring member between the ends of both brackets, there is no extreme restriction on the installation space compared to the conventional structure in which the spring is built into the support base.

For this reason, even if the spring is somewhat large, a spring with an appropriate elastic repulsion action, that is, a spring with a relatively small spring constant so that the elastic repulsion force changes gradually in response to displacement, is selected and installed. There will be no problem.

Therefore, compared to the case where a spring with a large spring constant is forcibly adopted, durability is improved and a smooth elastic repulsion action with room for the backrest can be obtained.

Furthermore, if the spring member is made of synthetic resin and has a continuous upright part and a horizontal part, it can be effectively used not only as a means for obtaining elastic biasing force but also as an armrest. As a result, added value increases. Moreover, since its cross section is approximately C-shaped, it can be made into an elastic body that is firmer and has a greater elastic repulsion effect than when a flat plate-shaped one is used.

Furthermore, when the above configuration is applied to a chair in which the backward tilting movement of the back support rod and the forward movement of the seat support member operate in conjunction, the seat support is The displacement of the spring member interposed between the two members is amplified by the amount that the member moves forward. Therefore, the elastic repulsion effect can be utilized in a wider deformation region, and the above-mentioned effects can be more prominently obtained.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, this chair with a backrest has a seat support member 3 connected to a leg post 2 that projects upward from a leg blade 1. Then, on the top plate 3a of this seat support member 3,
Two production control brackets 4.5 are rigidly attached in parallel with a certain distance between the front and rear.

Both brackets 4.5 each have a screw hole 4a.

5a are drilled, and when the seat 6 is placed, each screw hole 4a
, 5a through which bolts or the like can be inserted to fix the back surface of the seat 6 at the front and rear four corners. Further, the front bracket 4 is provided longer than the rear bracket 5, and L-shaped metal fittings 7 are attached to both ends of the bracket 4, respectively. This metal fitting 7 is arranged at such a position that its bent portion 7a can come into contact with the side surface of the seat 6 when the seat 6 is attached. A pin 8 is provided to protrude outward from the outer surface of the bent portion 7a.

On the other hand, from the rear of the seat support member 3, two ends of a back support rod 9 whose base end is rotatably supported on the seat support member 3 extend rearward and upward. A back side bracket 10 for fixing the backrest 11 to the upper end of this back support rod 9
is firmly attached. The dorsal bracket 10 has a length that roughly corresponds to the production bracket 4, and has L-shaped fittings 12 similar to those described above attached to both ends thereof, and pins extending outward from the outer surface thereof. 13 are installed protrudingly.

and a pin 8 protruding from the production control bracket 4;
Both ends of the spring member 14 are rotatably engaged with pins 13 protruding from the back bracket 1o. The spring portion 14 is an extensible rod with a coil spring elastically installed inside, and can be rotated between both brackets 4.5 by inserting both pins into engagement holes 14a and 14b protruding from both ends. is interposed.

With this configuration, the backrest 11 can be adjusted from the standard standing position.
When tilting backward, the distance between the dorsal bracket 10 provided on the back support rod 9 and the production bracket 4 provided on the seat support member 3 changes, and the The spring member 14 is elastically displaced. Along with this,
The elastic repulsive force of this spring member 14 gradually increases,
A force in the direction of eliminating the displacement acts on the back support rod 9, urging the backrest 11 toward the original standard standing position. As a result, the load is elastically supported at the rearward tilted position where the urging force balances the load applied to the backrest 11.

If the spring member 14 is provided at such a position, the installation space will not be severely restricted compared to the conventional case where the spring is built into the support base.

Therefore, even if the spring member 14 is somewhat large as shown in the drawing, it can be attached without any inconvenience. If the spring member 14 is made as large as this, it is possible to use a spring with a relatively small spring constant so that the elastic repulsive force changes gradually with respect to the amount of displacement. Compared to those that are used near the limit of their allowable displacement, the degree of fatigue due to repeated use is small. Therefore, durability is improved. Also, if you set the spring constant to a small value, the backrest will not be suddenly pushed back to the standard standing position when you raise your body.
A smooth elastic repulsion action can be ensured.

Next, another embodiment of the present invention will be described with reference to FIGS. 3 to 6. Note that the same reference numerals are given to the same parts as in the above embodiment.

As shown in FIG. 3, this sash with a backrest has a support base 2o between the seat support member 3 and the pillar 2. That is, whereas in the embodiment described above, the seat support member 3 was directly connected to the pedestal 2, here, the support base 20 is connected to the pedestal 2, and the seat support member 3 is connected to the support base 20 back and forth. It has a movably supported structure.

The support base 20 is made of die-cast aluminum, for example, and has side walls 20b erected on both left and right edges of a bottom wall that extends back and forth. Then, on both side walls 20b of this support base 20,
A balance member 101 as shown in FIG. 4 is attached to each shaft. The balance member 1.degree. 1 is in the form of a long and narrow plate that extends back and forth, and its middle portion is rotatably attached to the support base 20 via a shaft 102. Then, the left and right balance members 10
1 are connected to each other, and a back support rod 9 extends rearward and upward from the connected portion.

The seat support member 3 includes a frame-shaped top plate 3a and side plates 3b hanging from both left and right edges of the top plate 3a. are connected to the front ends of both side walls 20b of the support base 20 via
07 to the rear ends of both the balance members 101.

That is, the upper pivot ends of the left and right front link members 106 are pivotally attached to the front ends of these side plates 3b via the shaft 108, and the lower pivot ends of both front link members 106 are attached to the side walls of the support base 20. 20b via a shaft 109. Further, the upper pivot ends of the left and right rear link members 107 are pivotally attached to the rear ends of the side plates 3b of the seat support member 3 via shafts 111, and the lower pivot ends of these post-rain link members 107 are connected to the balance. It is pivotally connected to the rear end of the member 101 via a shaft 112. A long hole 113 extending back and forth is provided at the front end of both the balance members 101, and the long hole 113 is slidably connected to a shaft 110 provided at the rear pivot point of the front link member 106. There is. Note that the shaft 10
9 is wound with an auxiliary spring 116. One end of the auxiliary spring 116 is connected to the spring force adjustment mechanism 11 having a retainer 117a that can be projected and retracted into the support base 20.
7, and the other end is fixed to the retainer 117a of shaft 1.
It collided with 08. By changing the locking position, the restoring force of the backrest 11 can be adjusted.

Furthermore, in this embodiment, a spring member 21 made of synthetic resin as shown in FIGS. 4 to 6 is employed. This spring member 21 has a truncated shape when viewed from the side, and is made up of an upright portion 21a rising from the production control bracket 4 and a horizontal portion 21b extending forward from the back bracket 10, which are smoothly connected. The elastic repulsion effect is mainly caused by the upright portion 21
This is caused by a change in the angle formed between a and the horizontal portion 21b, and a biasing force is obtained when attempting to return the angle to the original angle. Bearings 21C are embedded at both ends thereof. Further, as shown in FIG. 6, the thick portion of the spring member 21 other than the portion where the bearing 21c is provided has both side edges 21d curved inward and expanded in the opposite direction to the direction of curvature. It has a central portion 21e that extends outward, and is formed to have a generally C-shaped cross section. When installing this spring member 20, both bearings 21c are pushed apart slightly in a direction that increases the distance between the bearings 21c.
c is rotatably supported by a pin 8 protruding from a birth control bracket 4 and a pin 13 protruding from a dorsal bracket 10, respectively.

Next, first, the operation of this embodiment will be explained.

In the standard standing posture shown by the solid line in FIG. 4, the backrest 11 is erected and the seat 6 is held at the most retracted position. This standing posture is suitable for working, etc. From this standing posture, the user leans back against the front rest 11 with his/her back.
When the user presses the backrest 11 backward, the balance member 101 rotates rearward about the shaft 102 serving as a fulcrum along with the backward tilting movement of the backrest 11. As a result, the balance member 101
The front end of the front link member 106 is moved upward, and the front link member 106 is rotated forward. As a result, the seat support member 3 moves forward, and the rear link member 107 supported at the rear end of the balance member 101 also rotates forward. At this time, the degree to which the entire rear link member 107 descends as the balance member 101 rotates is set to be greater than the degree that the shaft 111 at the upper stile attachment point rises due to the rotation of the rear link member 107. Therefore, the seat 4 apparently moves forward while gradually lowering its rear end. As a result, the spring member 21 rotates about the pins 8 and 13 in the bearings 21c at both ends, and elasticizes in response to the change in the distance between the birth control bracket 4 and the dorsal bracket 10, which gradually widens. While deforming the seat backrest 11, the elastic biasing force acting on the backrest 11 in the direction of the standard upright position is increased. Then, in the backward tilted position shown by the two-dot chain line in the figure, where the load applied to the backrest 11 and the elastic urging force by the spring member 21 are balanced, the load is stopped elastically.

However, if the spring member 21 is provided in such a shape, the horizontal part 21b can be used as an armrest at the same time, so if it is simply interposed between both brackets as a spring, it can be used as a spring. , by actively utilizing it, it becomes possible to completely eliminate waste. And since its cross section is approximately C-shaped,
Rather than simply molding into a flat plate, it is made of a spring that is firmer and has a greater elastic repulsion effect.

Furthermore, in this chair with a backrest, the backward tilting movement of the back support rod 9 and the forward movement of the seat support member 3 operate in conjunction with each other, so compared to a case where only the backrest 11 tilts, there is no need to intervene between the two. The amount of displacement of the spring member 21 is amplified. Therefore, the elastic repulsion effect of the spring member 21 can be utilized in a wider deformation region, and the effects in terms of durability and function described in the previous embodiment can be more significantly obtained.

Although each embodiment of the present invention has been described above, the cross-sectional shape of each part is not limited to that of the illustrated embodiment, and various modifications can be made without departing from the spirit of the present invention. for example,
In the embodiments shown in FIGS. 1 and 2, instead of using a metal coil spring, a so-called resin spring, rubber, or the like may be used.

[Effects of the Invention] With the above-described configuration, the present invention provides a chair with a backrest that improves the durability of the spring member and provides a smooth elastic rebound action with ample space in the backrest. can.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, with FIG. 1 being an exploded perspective view and FIG. 2 being a perspective view showing the completed state. 3 to 6 show other embodiments of the present invention, FIG. 3 is an exploded perspective view equivalent to FIG. 1, FIG. 4 is a side view showing the operation, and FIG. The plan view and FIG. 6 are an enlarged sectional view taken along the line ■-■ in FIG. 3... Seat support member 4... Production bracket 6... Seat 9... Back support rod 10... Back bracket 14... Spring member 20... Support base 21... Spring Member 21a... Standing part 21b... Horizontal part Fig. 2

Claims (1)

[Claims] 1. There is a back bracket between the end of the seat side bracket provided on the seat support member that supports the seat and the end of the back side bracket provided on the back support rod that can tilt in the front and back direction. A chair with a backrest characterized by interposing a spring member that elastically urges a support rod forward. 2. The spring member is made of synthetic resin and has an upright part that rises from the seat side bracket and a horizontal part that extends forward from the back side bracket that are smoothly continuous, and the cross-sectional shape of this spring member is approximately The chair with a backrest according to claim 1, characterized in that it is C-shaped. 3. The seat support member is supported on the support base so as to be movable back and forth, and the back support rod is pivotably supported on the support base so that the seat support member can be tilted back. 3. The chair with a backrest according to claim 1, wherein the chair is configured to be able to move forward relative to the support base.