JP3370132B2 - Chair reaction unit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reaction force unit suitable for use in office chairs and the like.

[0002]

2. Description of the Related Art As a reaction force generating means for applying a repulsive force to a backrest of a chair, there is known one in which a coil spring is interposed between members whose distance changes with the tilting of the backrest. . However, in the conventional one, the first retainer attached to one member, the second retainer attached to the other member, and the spring interposed between the retainers exist as independent small components, When assembling the chair, these parts are sequentially assembled.

[0003]

However, with such a structure, in the assembly line of a chair, a complicated work of assembling many small parts in a narrow space while resisting the biasing force of the coil spring. Becomes essential and causes a delay in the flow of the assembly line. Among the chairs used in offices these days, standard grades use coil springs, and luxury chairs and special purpose chairs use gas springs with a lock mechanism. It is required to meet various specifications. However, since the conventional coil spring specification has the above-mentioned configuration, it has a completely different form from the gas spring in which the mounting portion is unitized. Therefore, the coil spring specification and the gas spring specification require that the structure of the spring mounting portion be considerably different, and there is a certain limit to the common design.

The present invention aims to eliminate all such problems.

[0005]

The present invention takes the following means in order to achieve such an object. That is, the reaction force unit for a chair according to the present invention is used by being interposed between members whose distance changes when the backrest is tilted, and a pair of retainers and these retainers are separated from each other. It is characterized in that it is provided with a coupling mechanism which is capable of being engaged and disengaged in the axial direction within a certain range in an impossible manner, and a coil spring interposed between the both retainers.

In order to prevent the buckling of the coil spring and to simplify the coupling mechanism, the retainer has a tubular portion on the inner end side that slidably holds the inner periphery of the coil spring and the outer portion of the retainer. An end portion having a mounting portion that does not close the axial hole of the tubular portion, and a locking surface that locks the end surface of the coil spring at a boundary portion between the tubular portion and the mounting portion. Good to do.

In a preferred mode of the coupling mechanism in this case, one end side having a head portion is fixedly inserted into a shaft hole of one retainer and the other end side is slidably inserted into a shaft hole of the other retainer. An example is a shaft provided with a locking collar that is fixed to the other end of the center shaft and prevents the other retainer from coming off the center shaft. Specifically, it is desirable that the mounting portion is bifurcated and the head of the polygonal center shaft is press-fitted into the mounting portion.

In order to effectively prevent the generation of noise, it is preferable to interpose dampers wound around the center shaft between both retainers and between one retainer and the locking collar.

[0009]

With such a structure, the retainer having the mounting portion and the coil spring can be handled as an integral unit that cannot be separated, so that the assembling work in the chair assembling line is efficient. Can be done. That is, since the assembly of the repulsion unit including the coil spring can be processed by an appropriate sub-assembly line provided in parallel with the main assembly line of the chair, efficient manufacturing can be achieved as a whole.

Further, since the unit including the mounting portion is included, it has a function equivalent to that of the gas spring as a whole, and the handleability can be made the same. for that reason,
If both mounting portions of the reaction force unit of the present invention and both mounting portions of the gas spring are made to have the same shape and dimensions, the chair body side is completely commonized, and the coil spring specification and the gas spring specification are provided. Can be dealt with.

[0011]

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 sectional view showing the inside of the chair 1. In this chair 1, a seat frame 4 is pivotally attached to a front end of a seat bracket 3 fixed to an upper end of a leg support 2 via a shaft 5.
The base end of the back support rod 7 is supported by the center portion of the seat bracket 3 via a link member 6, and the portion near the base end of the back support rod 7 is attached to the rear end of the seat frame 4 via a shaft 8. It is pivotally attached, whereby the rearward tilt of the back support rod 7 and the tilt of the seat are interlocked.

Then, a reaction force unit 9 is interposed between the members that move in and out with the tilting of the backrest, that is, between the rear end of the seat bracket 3 and the intermediate portion of the back support rod 7 in this embodiment. In addition to elastically biasing the back support rod 7 forward, an auxiliary spring 10 is interposed between the seat bracket 3 and the seat frame 4 to assist the biasing function of the reaction force unit 9. .

As shown in FIGS. 2, 3 and 4, this reaction force unit 9 has a pair of retainers 11 and 110, and both retainers 11 and 110 cannot be detached from each other in the axial direction within a certain range. And a coil spring 13 interposed between the retainers 11 and 110.

The retainers 11 and 110 are made of, for example, synthetic resin reinforced with glass fiber, have a cylindrical portion 11a on the inner end side, and have a mounting portion 11b on the outer end side.
And a locking surface 11c for locking the end surface of the coil spring 13 at the boundary between the cylindrical portion 11a and the mounting portion 11b. The cylindrical portion 11a is for slidably holding the inner circumference of the coil spring 13, and has a shaft hole 11d in the shaft center portion. And on its outer circumference,
Vertical groove for accumulating grease and maintaining lubrication performance for a long period of time 1
A plurality of 1e are formed. The mounting portion 11b has a shape that does not close the shaft hole 11d of the cylindrical portion 11a, for example, a bifurcated shape. That is, the mounting portion 11b is, for example,
It has a pair of arms 11f that form a space continuous to the shaft hole 11d between the inner surfaces, and a shaft insertion hole 11g is provided at the tip ends of both arms 11f. A groove 11h for reducing friction is formed on the inner circumference of the shaft insertion hole 11g.

The coupling mechanism 12 includes a center shaft 1
2a and a locking brim 12b. The center shaft 12a is, for example, a metal shaft having a hexagonal head portion 12c, and its outer surface is plated with chrome. Although chrome plating is not essential, when the retainers 11 and 110 reinforced with glass fiber are used, it is desirable to perform chrome plating with high hardness to prevent wear of the center shaft 12a. A screw hole 12d is formed on the tip surface thereof. One end of the center shaft 12a having the head portion 12c is inserted into the shaft hole 11d of the one retainer 11, and the other end of the center shaft 12a is slidably inserted into the shaft hole 11d of the other retainer 110. In addition, the mounting portion 11 of one retainer 11
The inner surface 11n of b is formed into a substantially hexagonal cross section,
The head 12c of the center shaft 12a is attached to the inner surface 11n
The center shaft 12a is fixed to the one retainer 11 by being press-fitted into the retainer 11. The locking collar 12b is a washer-shaped member having a diameter larger than that of the center shaft 12a, and a bolt 12e screwed into the screw hole 12d.
Is fixed to the tip end surface of the center shaft 12a. The retainer 110 is prevented from coming off the center shaft 12a by the abutment of the locking flange 12b with the opening end surface of the shaft hole 11d.

A damper 12f is interposed between the retainers 11 and 110 and between the retainer 110 and the locking flange 12b. Each damper 12f is
For example, it is made of urethane and has a ring shape, and is disposed at the above-mentioned position in a state of being wound around the center shaft 12a.

Thus, one retainer 11 of this reaction force unit 9 is axially attached to the rear end portion of the seat bracket 3 via the shaft 14, and the other retainer 110 is attached to the back support rod via the shaft 15. It is attached to the middle part of 7.

With such a structure, when the backrest is tilted rearward, the distance between the rear end of the seat receiving bracket 3 and the middle portion of the back support rod 7 becomes gradually smaller, and the reaction force unit 9 shrinks. To be made. In that case, the other retainer 110 slides on the center shaft 12a press-fitted and fixed to one retainer 11, and the coil spring 13 is compressed while accumulating repulsive force. Become.
The compression of the coil spring 13 ends when the inner end of the other retainer 110 abuts and is locked by the inner end surface of the one retainer 11 via the damper 12f, and the backrest can be tilted further. become unable. When the external force on the backrest is removed in this state, the reaction force unit 9 extends due to the repulsive force of the coil spring 13, and the backrest self-returns forward. In this case,
The locking brim 12b contacts the other retainer 110 via the damper 12f, and further extension is prohibited.

However, with such a structure, both retainers 11 and 110 having the mounting portion 11b and the coil spring 13 can be handled as an integral unit, so that the assembly work in the chair assembly line can be performed. It can be done efficiently. That is, the assembly of the reaction force unit 9 including the coil spring 13 can be processed by an appropriate sub-assembly line provided in parallel with the main assembly line of the chair 1, so that efficient manufacturing can be performed as a whole. Becomes

Further, since the unit including the mounting portion is unitized, it has a function equivalent to that of the gas spring as a whole, and can be handled in the same manner. for that reason,
If both the mounting portions 11b of the reaction force unit 9 and the both mounting portions of the gas spring are made to have the same shape and dimension, the chair body side is completely commonized, and the coil spring specification and the gas spring specification are provided. Can be dealt with.

Further, if the retainers 11 and 110 have the above-mentioned tubular portion 11a, buckling can be effectively prevented even if a long coil spring 13 is used. Therefore, the spring constant can be reduced to flatten the reaction force constant, and a stable restoring force can be applied to the backrest. Further, the center shaft 12a is passed through the both tubular portions 11a,
Both retainers 11 along the center shaft 12a,
Since the 110 is moved in and out, the retainers 11 and 110 can be accurately moved linearly and the coil spring 13 can be appropriately expanded and contracted with a simple configuration. Moreover, since the mounting portion 11b does not close the axial hole 11d of the tubular portion 11a, the center shaft 12a can be passed through both the retainers 11 and 110, and the head portion 12c or the engaging portion can be attached to the through end. Both retainers 11 and 110 can be attached to the center shaft 12 only by providing the collar 12b.
It is possible to take measures so as not to separate from a. Therefore, it is possible to complete a unit that can be handled as an integrated product with a simple coupling mechanism.

Further, the mounting portion 11b has a bifurcated shape.
Since the head portion 12c of the rectangular center shaft 12a is press-fitted and fixed in the mounting portion 11b, the center shaft 12a does not rotate carelessly or does not move in the axial direction, and a stable operation is achieved. It becomes possible to secure.

Further, if dampers 12f are provided between the retainers 11 and 110 and between the retainer 110 and the locking brim 12b, the retainers 11 and 110 will be in contact with each other when the backrest is tilted to the end. It is possible to effectively suppress the generation of noise due to the collision of the above and the collision of the locking collar 12b and the retainer 110 when the backrest is self-returned to the front end and the generation of the tapping sound.

It should be noted that the shape of the retainer and the structure of the coupling mechanism are not limited to those of the illustrated embodiment, and the present invention also includes a damper omitted.

Besides, various modifications can be made without departing from the spirit of the present invention.

[0027]

As described above in detail, according to the present invention, the retainer having the mounting portion and the coil spring are unitized, so that the management of parts and the handling thereof can be simplified and the efficiency of the assembly line can be improved. The present invention has the effect that it can be used for a long time, and can cope with both the coil spring specification and the gas spring specification without a major design change of the chair body. In addition
The center part with a bifurcated mounting part and a polygonal shape.
Make sure that the head of the chaft is pressed into the mounting part and fixed.
For example, the center shaft may rotate carelessly or
It doesn't move. Furthermore, between both retainers and one
Insert dampers between the retainer and the locking collar.
If this is done, it is possible to effectively prevent the generation of noise.
It

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a side view showing the reaction force unit of the embodiment.

FIG. 3 is a plan view showing the reaction force unit.

4 is a sectional view taken along the line AA in FIG.

[Explanation of symbols]

1 ... Chair 9 ... Reaction force unit 11 ... Retainer 110 ... Retainer 11a ... Cylinder 11b ... Mounting part 11c ... Locking surface 11d ... Shaft hole 12 ... Coupling mechanism 12a ... Center shaft 12b ... locking collar 12c ... Head of center shaft 13 ... Coil spring

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) A47C 7/14 A47C 3/026 A47C 7/44

Claims (2)

(57) [Claims] 1. A reaction force unit for a chair, which is used by being interposed between members whose distance changes when the backrest is tilted, wherein a pair of retainers and these retainers are inseparable and constant. It comprises a coupling mechanism that couples in the axial direction so as to be able to contact and separate in the axial direction, and a coil spring interposed between the retainers, and the retainer slides on the inner circumference of the coil spring toward the inner end side. The coil spring has a tubular portion that is movably held, and an attachment portion that does not close the axial hole of the tubular portion on the outer end side, and the end surface of the coil spring is provided at the boundary between the tubular portion and the attachment portion. The coupling mechanism is provided with a locking surface, wherein the coupling mechanism has one end side having a head penetratingly fixed into a shaft hole of one retainer and the other end side slidably penetrating into a shaft hole of the other retainer. Inserted center shaft and this center shuff Of the center shaft, which is fixed to the other end of the center shaft and has a locking flange that prevents the other retainer from coming off the center shaft. It is pressed into the mounting portion, the locking collar, and formed in the distal end surface of the center shaft
Center shaft by means of bolts screwed into the screw holes
It is a reaction force unit for chairs, which is fixed to the tip surface of the chair. 2. A reaction force unit for a chair, which is used by being interposed between members whose distance changes when the backrest is tilted, wherein a pair of retainers and these retainers are inseparable and constant. It comprises a coupling mechanism that couples in the axial direction so as to be able to contact and separate in the axial direction, and a coil spring interposed between the retainers, and the retainer slides on the inner circumference of the coil spring toward the inner end side. The coil spring has a tubular portion that is movably held, and an attachment portion that does not close the axial hole of the tubular portion on the outer end side, and the end surface of the coil spring is provided at the boundary between the tubular portion and the attachment portion. The coupling mechanism is provided with a locking surface, wherein the coupling mechanism has one end side having a head penetratingly fixed into a shaft hole of one retainer and the other end side slidably penetrating into a shaft hole of the other retainer. Inserted center shaft and this center shuff Of the retainer, which is fixed to the other end of the retainer and prevents the other retainer from being separated from the center shaft.A damper is provided between the retainers and between the retainer and the retainer flange. Wrap it around the center shaft
Cage, said locking collar, bored in the distal end surface of the center shaft
Center shaft by means of bolts screwed into the screw holes
It is a reaction force unit for chairs, which is fixed to the tip surface of the chair.