JP2583188Y2 - Chair and backrest tilting device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tilting device for a seat and a backrest of a chair, and more particularly, to an improvement of a tilting device capable of tilting a backrest backward with respect to a seat by following a backward tilt of the seat. .

[0002]

2. Description of the Related Art Japanese Patent Publication No. Sho 56-49487, Japanese Utility Model Publication No. Sho 58-159954, and Japanese Utility Model Publication No. Sho 63-48205 disclose a tilting device for a chair capable of tilting a seat backward. These tilting devices include a support frame fixed to the upper end of the leg, a rear seat support pivotally attached to the support frame via a support shaft, and a front end of the rear seat support. And a front seat support coupled to the front seat support. The support shaft connecting the support frame and the rear seat support has a built-in torsion bar for imparting a torsional repulsive force to the rearward tilting of the rear seat support. Can be adjusted. In these seat tilting devices, since the support shaft incorporating the torsion bar is disposed immediately before the upper end of the leg, the front seat support is fixed when the rear seat support tilts backward. Or, by being tilted forward, the thigh of the seated person is prevented from being largely lifted upward.

On the other hand, Japanese Utility Model Laid-Open No. 5-2122 discloses a tilting device for a chair capable of tilting a seat and a backrest rearward. The tilting device includes a support frame having a rear end fixed to an upper end of the leg, a seat support having a front end pivotally attached to a front end of the support frame via a front support shaft, and A backrest support pivotally attached to the rear end of the seat support via a rear support shaft, and one end such that the backrest support tilts rearward with respect to the seat support following the rearward tilt of the seat support. And a connecting arm having the other end pivotally attached to the support frame and the front end of the backrest support. In this conventional device, a torsion bar is incorporated in a rear support shaft of a rear end portion of the seat support in order to impart a torsional repulsive force to the backward tilt of the seat support and the backrest support. The torsional repulsion can be adjusted by operating an operation knob. Further, both ends of the gas spring are respectively mounted on the front end of the support frame and the front end of the backrest support, and the valve of the gas spring is opened and closed by an adjustment lever to tilt the backrest support. The angle can be adjusted.

[0004]

In the case of the above-described seat tilting device, the front end of the rear seat support is flush with the support shaft, and the front end of the rear seat support moves upward when the rear seat support tilts rearward. Therefore, the drawback that the thigh of the seated person is lifted cannot be sufficiently solved. Further, when the rear seat support is tilted rearward, the front seat support is fixed or tilted forward, so that an excessive force such as pulling is applied to the cushion members mounted on the upper surfaces thereof, and the life thereof is shortened. Disadvantage. Further, when the center of gravity of the upper body of the seated person is located just above the support shaft, the torsion bar incorporated in the support shaft does not generate a torsional torque due to the weight of the body of the seated person. Cushioning properties cannot be obtained due to the backward tilting of the body and the torsional resilience of the torsion bar, giving the occupant discomfort. further,
Since the adjustment handle for adjusting the torsional repulsion of the torsion bar is located near the rear end of the rear seat support or near the legs, there is a disadvantage that the operation is difficult.

On the other hand, in the above-mentioned tilting device for the seat and the backrest, the front support shaft connecting the support frame and the seat support is disposed at the front end of the seat support. Although the problem that the front end rises when tilting rearward can be solved, the torsion bar is built into the rear support shaft that connects the seat support and the backrest support, and the operation for adjusting the initial twist amount of the torsion bar Since the knob is disposed below the front end of the seat support, a transmission mechanism such as a lever is required between the operation knob and the torsion bar, which causes a complicated structure.

Accordingly, an object of the present invention is to allow the seat support to be tilted rearward without greatly raising the front end of the seat support, and to allow the backrest to follow the seat by tilting backward. Provided is a simple chair seat and backrest tilting device that can be tilted and that can easily adjust the torsional repulsion of the torsion bar against the backward tilting of the seat support and the backrest support. It is in.

[0007]

In order to achieve the above object, the present invention provides a support frame having a rear end portion fixed to an upper end portion of a leg, and a front support shaft fixed to a front end portion of the support frame. A seat support having a front end pivotally attached to the support frame via the front support shaft so as to be able to tilt backward, and a backrest support pivotally attached to the rear end of the seat support via the rear support shaft. A connecting arm having both ends pivotally mounted on the support frame and the front end of the backrest support so that the backrest support can tilt rearward with respect to the seat support following the backward tilt of the seat support. In the seat and backrest tilting device
A torsion bar is inserted into the front support shaft using the front support shaft as a hollow shaft, one end of the torsion bar is fixed to one end of the front support shaft, and the torsion bar projects from the outer cylinder fixed to the other end of the torsion bar. A screw portion of the adjustment handle is screwed into a tip of the provided lever, and the tip of the screw portion is in contact with the lower surface of the seat support.

In the tilting device having the above structure, preferably, a coil spring is provided between the front end of the support frame and the front end of the backrest support, the coil spring being compressed by the rearward tilting of the seat support and the backrest support.

More preferably, brackets attached to the front and rear ends of the telescopic rod are respectively mounted on the front end of the support frame and the front end of the backrest support, and the coil spring is externally inserted into the telescopic rod and held between the front and rear brackets. Is done.

[0010]

In the chair and backrest tilting apparatus having the above-mentioned structure, the support frame, the seat support, the backrest support, and the connecting arm form a four-bar link, so that the seat support is tilted rearward. Then, the backrest support tilts backward in conjunction with the movement of the seat support. Since the seat support and the support frame are connected to each other via a front support shaft disposed at the front end of the seat support, the front end does not rise significantly when the seat support tilts rearward. . Therefore, it is possible to prevent the thigh of the seated person from being greatly lifted when the seat support is tilted backward. Also, the front support shaft in which the torsion bar is installed is located at the front end of the seat support, and in a normal use state, the center of gravity of the upper body of the occupant is not located immediately above the front support shaft. In any of the seating positions, it is possible to secure the cushioning property due to the backward tilting of the seat support and the torsional resilience of the torsion bar. Further, a torsion bar for giving a torsional repulsion to the seat support and the backrest support is provided in a front support shaft connecting the seat support and the support frame, and is used to adjust the torsional repulsion of the torsion bar. The adjustment handle is screwed to the tip of a lever protruding rearward from the outer cylinder fixed to the torsion bar and abuts against the lower surface of the seat support. In addition, it is located near the lower surface of the seat support, its operation is easy, and the connection structure between the adjustment handle and the torsion bar can be simplified.

When a coil spring is provided between the front end of the support frame and the front end of the backrest support, the coil spring is compressed by the backward tilt of the seat support and the backrest support. The torsion bar and the coil spring can share and hold the elastic repulsion force against tilting, so it is possible to use a torsion bar with a small torsion spring constant, and the adjustment handle adjusts the torsion bar torsion repulsion force with a light force. It can be done easily.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view of a tilting device for a chair seat and a backrest according to an embodiment of the present invention, FIG. 2 is a front view of the tilting device, and FIG. 3 is a side view showing the operation of the tilting device. FIG. Referring first to FIGS. 1 and 2, a tilting device for a chair seat and a backrest includes a leg 1 having a caster (not shown) at a lower end, and a rear end fixed to an upper end of the leg 1. A support frame 2, a front support shaft 3 having a hollow shaft structure fixed to the front end of the support frame 2, and a seat support having the front end pivotally attached to the support frame 2 via the front support shaft 3 so as to be tiltable rearward. 4, a backrest support 6 pivotally attached to the rear end of the seat support 4 via a rear support shaft 5,
Both ends of the support frame 8 and the front end of the backrest support 6 are supported by the support shafts 8 and 9 so that the backrest support 6 tilts rearward with respect to the seat support 4 following the backward tilt of the seat support 4. And a connecting arm 7 which is axially mounted via the arm. Although not shown, a cushion body is attached to each of the upper surface of the seat support 4 and the upper portion of the backrest support 6.

As shown in FIG. 2, both ends of the front support shaft 3 protrude from both sides of the support frame 2 and are rotatably fitted to the seat support 4 on the outer periphery of both ends of the front support shaft. Bearing cylinders 10 and 11 are fixed. The torsion bar 12 is inserted into the front support shaft 3, one end of the torsion bar 12 is fixed to one end (the left end in FIG. 2) of the front support shaft 3, and the other end of the torsion bar 12 Is fixed to an outer cylinder 13 rotatably fitted to the outer circumference of a bearing cylinder 11 fitted to the outer circumference of the other end of the front support shaft 3. A lever 14 projecting rearward is fixed to the outer cylinder 13. A screw portion 15 a of an adjustment handle 15 is screwed into a screw hole formed at the tip of the lever 14. Is arranged so that the front end thereof abuts on the lower surface of the seat support 4 behind the front support shaft 3.

Further, in this embodiment, a coil spring 16 is provided between the front end of the support frame 2 and the front end of the backrest support 6, and is compressed by the rearward tilt of the seat support 4 and the backrest support 6. ing. More specifically, in this embodiment, a front bracket 18 attached to a front end of a telescopic rod 17 is attached to a front end of the support frame 2 via a support shaft 19, and is attached to a front end of the backrest support 6. The rear bracket 20 attached to the rear end of the telescopic rod 17 is pivotally mounted via a support shaft 9 that supports the connecting arm 7. The coil spring 16 is externally inserted into a telescopic rod 17 and held between the front and rear brackets 18 and 20.

In the tilting device for the seat and backrest of the chair having the above structure, the support frame 2, the seat support 4, the backrest support 6, and the connecting arm 7 form a four-bar link.
When the seat support 4 tilts rearward, the backrest support 6 tilts rearward in conjunction with the movement of the seat support 4. Since the seat support 4 and the support frame 2 are connected to each other via the front support shaft 3 disposed at the front end of the seat support 4, the front end of the seat support 4 is tilted when the seat support 4 tilts rearward. There is no significant rise. Therefore, it is possible to prevent the thigh of the seated person from being greatly lifted when the seat support 4 is tilted backward.

The front support shaft 3 in which the torsion bar 12 is provided is located at the front end of the seat support 4, and the center of gravity of the upper body of the occupant is located immediately above the front support shaft 3 in a normal use state. The seat support 4 in any sitting position
The cushioning property due to the backward tilting and the torsional repulsion of the torsion bar 12 can be secured.

Further, the seat support 4 and the back support 6
A torsion bar 12 for providing a torsional repulsive force is provided in the front support shaft 3 connecting the seat support 4 and the support frame 2, and an adjusting handle 15 for adjusting the torsional repulsive force of the torsion bar 12 is provided. Since the screw portion 15a is screwed to the tip of a lever 14 projecting rearward from the outer cylinder 13 fixed to the torsion bar 12, and the tip is in contact with the lower surface of the seat support 4, the adjustment handle is provided. 15 is located in the vicinity of the front end of the seat support 4 and in the vicinity of the lower surface of the seat support 4 so that the operation is easy and the adjustment handle 15 is provided.
And the connection structure between the torsion bar 12 and the torsion bar 12 can be simplified.

Further, in the above embodiment, the support frame 2
Of the seat support 4 and the backrest support 6 between the front end of the backrest support 6 and the front end of the coil spring 1
6, the seat support 4 and the backrest support 6
The elastic repulsion force against the rearward tilting can be shared and held by the torsion bar 12 and the coil spring 16. Therefore, the torsion bar 12 having a small torsion spring constant can be used, and the adjustment of the torsion repulsive force of the torsion bar 12 by the adjustment handle 15 can be easily performed with a small force.

Although the illustrated embodiment has been described above, the present invention is not limited to the above embodiment.
For example, the coil spring 16 is omitted and the torsion bar 12
An elastic repulsive force may be applied to the rearward tilting of the seat support 4 and the backrest support 6 only by using only the seat support 4 and the backrest support 6. Further, a torsion bar is provided in the rear support shaft 5 having a hollow shaft structure instead of the coil spring 16, and one end thereof is fixed to one end of the rear support shaft 5 and the other end is fixed to the backrest support 6. The torsion bar 12 in the front support shaft 3 and the torsion bar in the rear support shaft 5 may apply elastic repulsion to the seat support 4 and the backrest support 6. In this case, the appearance of the chair can be simplified.

[0021]

As is apparent from the above description, in the present invention, the front support shaft for supporting the seat support is arranged at the front end of the seat support, and at the rear of the seat support and the backrest support. Since the torsion bar that gives elastic repulsion to tilting is provided in the front support shaft, the seat support can be tilted rearward without greatly raising the front end of the seat support, and the seat can be tilted rearward. The chair has a structure in which the backrest can be tilted rearward with respect to the seat by following the backrest, and the torsion bar can easily adjust the torsional repulsion force of the seat support and the backrest support with respect to the backward tilt. A tilting device for the seat and the backrest can be provided.

[Brief description of the drawings]

FIG. 1 is a side view of a tilting device for a seat and a backrest of a chair according to an embodiment of the present invention.

FIG. 2 is a front view of the tilting device shown in FIG.

FIG. 3 is a side view showing a state where the seat support and the backrest support of the tilting device shown in FIG. 1 are tilted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Leg 2 Support frame 3 Front support shaft 4 Seat support 5 Rear support shaft 6 Back support 7 Connection arm 12 Torsion bar 13 Outer cylinder 14 Lever 15 Adjusting handle 15a Screw part 16 Coil spring 17 Telescopic shaft 18 Front bracket 20 rear bracket

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) A47C 3/02 A47C 3/025 A47C 3/026

Claims (3)

(57) [Scope of request for utility model registration] 1. A support frame (2) having a rear end fixed to an upper end of a leg (1), a front support shaft (3) fixed to a front end of the support frame, and a front support shaft. A seat support (4) having a front end pivotally attached to the support frame so as to be tiltable rearward; and a backrest support (6) pivotally attached to a rear end of the seat support via a rear support shaft (5). ), And a connecting arm (both ends of which are pivotally attached to the support frame and the front end of the backrest support so that the backrest support tilts rearward with respect to the seat support following the backward tilt of the seat support, respectively). 7) a tilting device for a seat and a backrest of a chair comprising: a front support shaft (3) having a hollow shaft and a torsion bar (12) inserted into the front support shaft; An adjustment handle (15) is fixed to one end of the shaft and the tip of a lever (14) protruding from an outer cylinder (13) fixed to the other end of the torsion bar. The threaded portion screwed (15a), the tip of the seat support of the threaded portion (4) seat and backrest tilting device of the chair, characterized in that in contact with the lower surface of the. 2. A front end of a support frame (2) and a backrest support (6).
2. A chair seat according to claim 1, further comprising a coil spring (16) compressed by the rearward tilting of the seat support (4) and the backrest support (6). Backrest tilting device. 3. A front end of a support frame (2) and a backrest support (6).
Brackets (18, 20) attached to the front and rear ends of the telescopic rod (17) are respectively attached to the front ends of the telescopic rods, and a coil spring (16) extrapolated to the telescopic rod is held between the front and rear brackets. 3. A tilting device for a seat and a backrest of a chair according to claim 2.