JPH11178670A - Rocking structure of chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability of a chair which is tilted rearward, a seat back and a seat body acting in association with each other. SOLUTION: A seat body 3 is mounted to a first axis 6 attached to the front part of a seat receiving base 2 so as to be movable back and forth. The forward end of a back supporting rod 9 is pivotally supported on the base 2 through a second axis 10. The seat body 3 and the rod 9 are rotatably connected by a third axis 11. A fourth axis 16 is provided near the second axis 10 in the base 2, and one of the ends of a gas cylinder 18 is attached to the axis 16 through a bracket and the other end of the cylinder 18 is fitted on the axis 6. A rotary operation tool 22 is rotatably fitted on the axis 16 and a push rod 25 of the gas cylinder 18 is directly pushed by the tool 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rocking structure (synchro structure) for a chair in which a backrest and a seat body are tilted backward in conjunction with each other.

[0002]

2. Description of the Related Art Some chairs for office use and the like are configured such that when the backrest tilts backward, the seat body tilts backward and retreats in conjunction with this. As one example, as schematically shown in FIG. 7, a seat base B provided at an upper end of a leg A is provided.
A long hole C extending obliquely in a side view is provided at a front portion of the back support rod G, and a left-right long first axis D inserted into the long hole C is attached to the seat body E, and a backrest F is attached thereto. The part is rotatably attached to the seating base B by a second axis H located at a position behind the first axis D, and the third body E and the back support rod G are interlocked with each other. Connected by a shaft I, and a gas cylinder J between a first shaft D and a second shaft H.
Is interposed.

In this structure, when a seated person leans against the backrest F, the backrest F tilts rearward about the second axis H, and the seat body E tilts rearward while retracting by being pulled by the backrest F. The rearward tilt of the backrest F and the rearward tilt of the seat body E are elastically supported by the gas cylinder J. Further, when the gas cylinder J is locked in an arbitrary posture in which the backrest F is inclined, the backrest F and the seat body E are held in that posture.

[0004]

The load (weight of the upper body of a person) applied to the seat body E and the backrest F is supported by three axes D, H, and I. Since the gas cylinder J is attached, the backrest load and the pressing force of the gas cylinder J act on the second shaft H in different directions, and therefore the burden on the second shaft H is large. Therefore, there is a problem that the durability of the second shaft H is low.

Further, since the operation mechanism for locking and unlocking the gas cylinder J is also composed of a plurality of parts, there is a problem in that the manufacturing cost is increased and the assembly is troublesome. An object of the present invention is to solve these problems.

[0006]

To achieve the above object, the present invention provides a seat base provided at an upper end of a leg, a seat body located above the base, a back support rod extending rearward from the seat base. And a backrest attached to the front of the seat support base by a left-right longitudinal first axis so that the seat body can be moved backward while tilting backward. Is attached to the seat receiving base with a left and right longitudinal second axis so that it can be tilted rearward around the center, and the seat body and the back support rod are coupled to each other in a left and right longitudinal third axis so as to tilt backward. And a fourth shaft extending substantially parallel to the first shaft is fixed to a portion behind the first shaft of the seat base so as to be immovable in the forward and backward directions. A spring means is interposed between the shaft and the shaft. "

[0007]

With this configuration, only the load from the back support rod acts on the second shaft, which is the pivot of the backrest, while the load from the spring means acts on the fourth shaft. Only a large force acts intensively on a particular axis. Therefore, according to the present invention, it is possible to prevent the load from being concentrated on a specific shaft and improve the durability of the chair.

According to the second aspect of the present invention, since only a rotor type operating tool is required as an operating means of the gas cylinder, the number of parts can be reduced as compared with the conventional one, and the manufacturing cost of the chair is extended. Can be reduced.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a right side view of the chair. As shown in FIG. 1, the chair includes a leg 1 having a built-in elevating gas cylinder, a seat base (lower base) 2 fixed to the upper end of the leg 1, and a seat. A seat 3 and a backrest 4 are attached to the receiving base 2 so as to be tiltable rearward.

FIG. 2 is a plan view showing the seat body 3 by imaginary lines.
3 (A) is a sectional view taken along the line IIIA-IIIA of FIG. 2, and FIG. 4 is a sectional view of FIGS.
(A) is a sectional view taken along the line IV-IV. As shown in these figures, the seat receiving base 2 is formed in a U-shape in a positive cross section that opens upward, while the lower surface of the seat body 3 has A U-shaped upper base (bracket) 5 having a downward opening in a regular cross section is fixed to the seating base 2 from above. , 2b allows the first shaft 6 to pass therethrough, thereby allowing the seat body 3 to tilt backward.

In this case, for example, as shown in FIG.
By setting the insertion hole 7 of the seat receiving base 2 in which the shaft 6 fits as a long hole that is gradually inclined rearward, the seat body 3 is set to be able to retreat while tilting backward. A bearing 8 made of synthetic resin or the like is mounted in the insertion hole 7. The upper base 5 is made of a metal plate, and therefore, the seat 3 is basically a rigid body that does not bend and deform.

The backrest 4 is provided with a pair of left and right back support rods 9 extending rearward on both left and right sides of the seat support base 2, and a cylindrical portion 9 a is provided at a front end of the back support rod 9. A second shaft is attached to the left and right side plates 2a, 2b of the seat base 2.
Penetrates 10 Therefore, the back support rod 9 and the backrest 4
Can tilt in the front-rear direction about the second axis 10. 2nd axis
10 is located slightly forward of leg 1.

The right and left back support rods 9 are provided with support pieces 9b, which are located outside the rear ends of the left and right side plates 5a and 5b of the upper base 5, and project upward. The third shaft 11 passes through the left and right plates 5a and 5b.
Therefore, when the backrest 4 tilts rearward, the seat body 3 retreats while gently tilting rearward. As shown in FIGS. 2 and 4, a collar 12 for positioning is fitted on the third shaft 11.
The left and right back support rods 9 are reinforced plates near the support pieces 9b.
Connected at 13.

As shown in FIGS. 2 and 3 (A), a reinforcing frame 14 having a downward opening extending between the left and right side plates 2a and 2b is fixed to a rear portion of the seat receiving base 2. Push rod 15 is exposed from a hole provided in the reinforcing frame 14. Although not shown, an elevating operation lever for pushing down the push rod 15 of the elevating gas cylinder is rotatably mounted on the upper surface of the reinforcing frame.

In the vicinity of the second shaft 10 of the seat base 2, a fourth shaft having a quadrangular cross section (or a circular shape or the like) and having a long side is used.
The bearing 17 is fitted to the side plates 2a, 2b of the seat base 2.
A gas cylinder 18 as an example of a spring means is disposed between the fourth shaft 16 and the first shaft 6, and the front end of the gas cylinder 18 is fitted on the first shaft 6. The gas cylinder 18 is displaced toward the right side of the seat base 2, and the first shaft 6 is fitted with a spacer 19 for preventing the gas cylinder 18 from shifting.

FIG. 5 is an exploded perspective view of a main part.
As shown in FIG. 3A and FIG. 3A, a bush 20 having a flange on one side is fitted into the fourth shaft 16.
A bracket 21 having a substantially U-shape in plan view and a rotary operating tool 22 having a cylindrical shape are fitted on the bracket 21. Operation tool 22 is a bracket
The operating tool 22 is integrally provided with a lever 24 projecting outward from an arc hole 23 formed in the right side plate 2b of the seat base 2. .
Therefore, the operating tool 22 can be rotated by rotating the lever 24 around the axis of the fourth shaft 16 along the arc hole 23.

The operating tool 22 may be made of synthetic resin or metal. When the operating tool 22 is made of synthetic resin, it is preferable to integrally form the lever 24. As clearly shown in the enlarged view of FIG. 6, the bracket 21 has a piston rod 18a of the gas cylinder 18 attached thereto.
Is fixed, and a push rod (push valve) 25 is provided at the tip of the piston rod 18a.

The push rod 25 is desired on the outer peripheral surface of the operating tool 22. The push rod 25 is provided on the outer peripheral surface of the operating tool 22 such that the push rod 25 is switched so as to project or retreat by rotation of the operating tool 22. The guide grooves 26 and 27 are formed continuously. Both guide grooves 26 and 27 are formed in a concave shape so that the push rod 25 is fitted in a stable state. Note that the operating tool 22 can be further rotated clockwise from the state of FIG. 6A, and in this state, the push rod 25 remains retracted. The length of the arc hole 23 may be set so that the operation tool 22 cannot be rotated clockwise from the state of FIG. 6 (A).

As shown in FIG. 2, a spacer 28 for positioning the bracket 21 is also fitted on the fourth shaft 16.
The fourth shaft 26 is prevented from falling off by a snap ring or the like. The pivotal support structure of the back support rod 9 by the second shaft 10 is shown in FIG.
It looks like 4 (B). That is, while the second shaft 10 is inserted through the bearing 29 mounted on the seat base 2, the bush 30 with the spacer portion 30a is inserted into the cylindrical portion 9a provided on the back support rod 9.
And the second shaft 10 is fitted into the bush 30,
Further, a snap ring 31 for retaining is fitted on the end of the first shaft 10 in the hollow space of the cylindrical portion 9a, and a detachable cap 32 is mounted on the cylindrical portion 9a of the left and right back support rod 9. It is. With this configuration, since the second shaft 10 is not exposed to the outside, the external appearance is clear and the appearance is excellent.

In the above configuration, when the operating tool 22 is rotated as shown in FIG. 6A, the push rod 25 of the gas cylinder 18 is pushed and locked. Therefore, even if the seated person leans on the backrest 4, the backrest 4 and the seat body 3 do not tilt backward. On the other hand, when the operating tool 22 is brought into the state shown in FIG. 6B by rotating the lever 24, the push rod 25 of the gas cylinder 18 is pushed and the lock is released, so that the seated person When this is also applied, the backrest 4 and the seat receiving base 3 are tilted rearward against the gas cylinder 18.

The back support rod 9 is supported by the second shaft 10,
Since the gas cylinder 18 is supported by the fourth shaft 16,
The load applied to the backrest 4 and the seat 3 is 6,10,11,22
Therefore, the durability of the chair as a whole can be improved. Further, since the push rod 25 of the gas cylinder 18 is directly pushed by the rotary operation tool 22, the operation mechanism of the gas cylinder 18 is simplified, and the manufacturing cost (part processing cost and assembly cost) is reduced. Can be reduced.

When an arc hole (a long hole) 23 for guiding rotation of the lever 24 is formed in the seat base 2 as in the embodiment, the seat base 2 can be used also as a guide member of the lever 24, so that the structure is reduced. There is an advantage that can be simplified. Further, since the operating tool 22 is fitted into the bush 26, the operating tool 22 is accurately rotated by the turning operation of the lever 24, and this fact and the turning radius R of the lever 24 (FIG. 6 (A) (See FIG. 2), the rotation moment of the operation tool 22 can be increased, and the rotation of the lever 24 is guided by the arc hole 23. Can be rotated smoothly. That is, the operation of locking / unlocking the gas cylinder 18 can be accurately performed with a small force.

A gas cylinder is preferable as the spring means of the present invention. However, if the function of locking the backrest and the seat body is not required, an elastic body such as a coil spring or rubber may be used.

[Brief description of the drawings]

FIG. 1 is a right side view of a chair according to an embodiment of the present invention.

FIG. 2 is a plan view in a state where a seat body is indicated by a virtual line.

3A is a sectional view taken along the line IIIA-IIIA in FIG. 2, and FIG.
FIG.

FIG. 4 is a sectional view taken along line IV-IV of FIGS. 2 and 3;

FIG. 5 is an exploded perspective view of a main part.

FIG. 6 is a diagram showing an operation.

FIG. 7 is a skeleton diagram of the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Leg 2 Seat base 3 Seat 4 Backrest 6 1st axis 9 Backrest support rod 10 2nd axis 11 3rd axis 16 4th axis 18 Gas cylinder 18a Gas cylinder piston rod 21 Bracket 22 Operating tool 24 Lever 25 Push rod

Claims (2)

[Claims] 1. A seat base provided at an upper end of a leg, a seat body located above the base, and a backrest attached to a back support rod extending rearward from the seat base, the seat body being tilted rearward. A left and right longitudinal second shaft is attached to the front of the seat base by a left and right longitudinal first shaft so that the back support rod can be tilted rearward about the front portion. The seat body and the back support rod are rotatably connected to each other by a third shaft extending in the left and right direction so that the two are tilted backward in conjunction with each other. A fourth shaft extending substantially parallel to the first shaft is immovably attached to a portion behind the first shaft, and spring means is interposed between the fourth shaft and the first shaft. Characteristic chair locking structure. 2. The gas cylinder according to claim 1, wherein the spring means is a gas cylinder having a push rod for switching between a locked state and an unlocked state, and the push rod of the gas cylinder is attached to the fourth shaft. A locking mechanism for the chair, wherein a rotary operation tool for directly pushing and returning the push rod by a rotation operation from the outside of the seat base is fitted on the fourth shaft; Construction.