JP3652401B2 - Chair back tilt device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an office chair, and more particularly to a chair back tilting device.
[0002]
[Prior art]
Conventional chairs used for office work have a backrest on the back and can be reclined (tilted).
[0003]
In the tilting chair, a spring is used as disclosed in, for example, Japanese Utility Model Laid-Open No. 59-125261 and Japanese Patent Laid-Open No. 2-224617, and this spring is attached to the cradle of the chair. At that time, the reaction force is indirectly transmitted to the back frame through a link formed of steel or resin, and the load applied to the back is supported.
[0004]
[Problems to be solved by the invention]
However, in such a structure, the arrangement of the spring and the link is largely restricted by the size of the cradle and the angle at which the back is tilted. I had to use it.
[0005]
And in order to ensure the strength of each part corresponding to it, there is a problem that it leads to an increase in weight, the number of parts, and cost increase.
[0006]
In addition, since the space for the cradle is limited, it is not possible to use a spring with a long free length, which often results in a chair with a strong spring feeling and a poor comfort.
[0007]
SUMMARY OF THE INVENTION In view of this, the present invention aims to provide a chair back tilting device that can easily select a panel and obtain a natural seating comfort without a feeling of spring, and to solve the disadvantages of the prior art. It is a thing.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a pedestal positioned at a lower portion of a seat cushion, a back frame rotatably supported by a shaft on the pedestal, and a back frame fixed to a rear portion of the back frame. In a chair provided with a back strut having a cushion, a spring having a front end supported in the cradle is provided in the front-rear direction, and one end of a rope is connected to the rear end so as to be rotatably supported in the cradle. The direction of the rope is changed along the rope guide ring, and the other end of the rope has a rope stopper that penetrates the cradle and is fixed to the back frame outside thereof.
[0009]
[Action]
According to the above configuration, since the reaction force of the spring can be directly transmitted to the back frame, a spring having a relatively small constant can be used.
[0010]
【Example】
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0011]
As shown in FIGS. 1 to 3, the chair back tilting apparatus according to the present invention includes a pedestal 2 positioned at a lower portion of a seat cushion 1 and a back supported by the pedestal 2 so as to be rotatable by a shaft 3. In a chair provided with a frame 4 and a back column 6 fixed to the rear portion of the back frame 4 and having a back cushion 5 at the top, a spring 7 having a front end supported in the cradle 2 is provided in the front-rear direction. One end of the rope 8 is connected to the rear end thereof, and the direction of the rope 8 is changed along the rope guide wheel 9 rotatably supported in the cradle 2 and the other end of the rope 8 is received. It has a rope stopper 10 that passes through the base 2 and is fixed to the back frame 4 outside thereof.
[0012]
A gas spring receiver 11 is provided at the bottom of the cradle 2, and a gas spring 12 is connected thereto. The operation of the gas spring 12 can arbitrarily adjust the height of the cradle 2.
[0013]
The front end of the spring 7 is hooked on an adjustment bolt 14 screwed into a nut portion 13a of an adjustment dial 13 provided on the outside of the front portion of the cradle 2 so as to be freely rotatable. The rotation of the spring 7 can be adjusted by rotating the adjustment dial 13.
[0014]
A shaft 15 is fixed to the rear portion of the cradle 2, and the rope guide wheel 9 is rotatably supported on the shaft 15.
[0015]
One end of the rope 8 such as a wire is attached to the rear end of the spring 7 attached in a straight line with the adjusting bolt 14, and the middle is along the outer periphery of the rope guide ring 9 via the rope stopper 16. The other end hangs in a substantially right-angle direction, and the other end passes through a hole 2a provided on the lower surface of the cradle 2 and further passes through a hole 4a provided on the lower surface of the back frame 4 positioned below the lower surface. Are fixed by the rope stopper 10.
[0016]
The back frame 4 is supported so as to be tiltable in the vertical direction with respect to the cradle 2 with the shaft 3 as a fulcrum, and the back cushion 5 at the upper part of the back column 6 integrated therewith also tilts in the front-back direction with respect to the cradle 2. It will be possible.
[0017]
In FIG. 3, 17 is a back frame receiver, and 18 is a seat cover mounting bracket.
[0018]
Next, the operation will be described.
[0019]
In FIG. 3, when a force in a backward tilting direction is applied to the back cushion 5 of the chair, the back frame 4 integrated with the back column 6 rotates about the shaft 3, and thus the rope stopper fixed to the back frame 4 10 is pulled downward. As a result, the cord 8 is pulled, so that the spring 7 is extended by a length corresponding to the force applied to the back cushion 5, and the rearward tilt state shown in FIG. 4 is obtained.
[0020]
At this time, the spring feeling (stiffness or softness) of the back cushion 5 can be adjusted by turning the adjustment dial 13 and pulling or pushing the adjustment bolt 14, so that the extension of the spring 7 is changed. The reaction force can be changed.
[0021]
Further, in order to return to the state shown in FIG. 4 from FIG. 3, that is, for a sudden return in which the force applied to the back cushion 5 is lost, a known means is provided so that the rope 8 does not come off the rope guide wheel 9. Can be prevented.
[0022]
In the embodiment, the wire 8 is used as the wire. However, this may be a chain, and the guide wheel 9 may be a sprocket, or a belt and a pulley. Although the description has been given of the case where the spring is a tension spring, it is needless to say that the same action as that of the tension spring can be achieved even if a compression spring is used and the cord is connected so as to pull the rope during compression.
[0023]
【The invention's effect】
As described above, the present invention provides a pedestal positioned at the lower part of the seat cushion, a back frame rotatably supported on the pedestal by a shaft, and a back cushion fixed to the rear part of the back frame. In the chair provided with a back strut having a spring, a spring having a front end supported in the cradle is provided in the front-rear direction, and one end of a rope is connected to the rear end to be rotatably supported in the cradle. By changing the direction of the rope along the rope guide ring, the other end of the rope is provided with a rope stopper that passes through the cradle and is fixed to the back frame outside thereof. Regardless of the tilt angle of the column, the direction in which the spring expands and contracts does not change, and the spring force can always be applied smoothly, thereby providing a comfortable sitting feeling with a spring feeling.
[0024]
Also, unlike the conventional case where the spring and the back frame are connected via a link, the spring force does not change due to the displacement of the link, so it is not necessary to use a spring with a large spring constant. The chair can have a good spring feeling.
[0025]
Furthermore, since the connection between the spring and the back frame is only the rope, the installation space can be reduced, the pedestal can be made small, and the number of parts is small, so that assembly is facilitated. And since the installation position of the dial for adjusting the spring pressure can be freely selected, there is an effect that the degree of freedom in design increases and the design is advantageous.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a chair back tilting apparatus according to the present invention.
FIG. 2 is a plan view of FIG.
3 is a cross-sectional view taken along the line AA in FIG. 2 when tilting forward.
4 is a cross-sectional view taken along the line AA when tilting backward in FIG. 2;
[Explanation of symbols]
1 Seat Cushion 2 Receiving Base 2a Hole 3 Shaft 4 Back Frame 4a Hole 5 Back Cushion 6 Back Strut 7 Spring 8 Line 9 Line Guide Outer Ring 10 Line Stop

Claims (1)

A chair provided with a cradle positioned at the lower part of the seat cushion, a back frame rotatably supported on the cradle by a shaft, and a back column fixed to the rear part of the back frame and having a back cushion at the upper part A spring having a front end supported in the cradle is provided in the front-rear direction, and one end of the rope is connected to the rear end of the spring along a rope guide ring rotatably supported in the cradle. A back tilting device for a chair, characterized in that the direction of the strip is changed and the other end of the strip has a strip stop that passes through the cradle and is fixed to the back frame outside thereof.

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