JPH11253264A - Supporting mechanism of chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the adjustment of the reactive force of rocking and to eliminate a feeling of being pressed and a sense of instability at the thigh at the time of rocking. SOLUTION: A supporting mechanism 1 of a chair to support a backside seat 3, which is a member to be supported, so as to be capable of rocking with respect to a seat receiving member 2, which is a supporting member, is provided with the first link member 4 provided with a biasing means 5 to store an elastic reactive force by displacement and capable of being elevated and contracted, the second link member 14 to be interlocked with the back side seat 3 to rock and the third link member 11 to be fixed. The one ends of the first link member 4 and the third link member 11 are rotatably connected to the second link member 14, and the other ends of the first link member 4 and the third link member 11 are rotatably connected to each other to constitute a constraint rotational chain. By making the fixed location of the third link member 11 movable by an adjusting screw 12, it is possible to adjust the size of the reactive force of the rocking of the backside seat 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chair supporting mechanism capable of locking a seat and a backrest. More specifically, the present invention relates to a chair supporting mechanism capable of adjusting a reaction force of rocking.

[0002]

2. Description of the Related Art In a chair in which a seat and a backrest can be locked, an urging spring including a compression coil spring or a gas spring is used to return the seat or the backrest to an original position. There is a chair provided with a rocking reaction force adjusting mechanism in order to adjust the magnitude of the rocking reaction force according to the physique and the use state of the seated person.

As this reaction force adjusting mechanism, there is one that changes the initial compression length of an urging spring using, for example, an adjusting screw. This is to change the initial pressure of the biasing spring by changing the initial compression length of the biasing spring to adjust the magnitude of the reaction force of the locking.

As another example of the reaction force adjusting mechanism, there is a mechanism in which an urging spring is inclined to change an angle of urging the seat or the like. This is to change the direction in which the bias spring is biased toward the seat or the like by inclining the bias spring using, for example, an adjustment screw around a portion attached to the seat or the like of the bias spring. Thus, the reaction force received from the urging spring when the seat or the backrest is inclined changes, so that the magnitude of the reaction force of the locking can be adjusted.

[0005]

However, in the above-described reaction force adjusting mechanism for changing the initial compression length of the biasing spring, it is necessary to rotate the adjusting screw in the tightening direction in order to increase the reaction force. A large operation force is required. For this reason, the operability is particularly poor for a woman or the like with weak power.

In the above-described reaction force adjusting mechanism for changing the biasing angle of the biasing spring, the initial compression length is constant even if the biasing angle of the biasing spring is changed. I can't. For this reason, the initial reaction force of the backrest and the rocking of the seat becomes substantially constant, so that the feeling of use of the chair is not so good.

Accordingly, an object of the present invention is to provide a chair supporting mechanism capable of adjusting the reaction force of rocking with good operability.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a chair supporting mechanism for supporting a supported member in a rockable manner with respect to a supporting member. A first link member that can be extended and contracted with an urging means for storing, a second link member that swings in conjunction with a supported member, and a third link member that is fixed; One end of the link member and the third link member are rotatably connected, and the other end of the first link member and the third link member are rotatably connected to each other to form a constrained rotation chain. By making the fixed position movable with an adjusting screw, the magnitude of the reaction force of the locking of the supported member can be adjusted.

Therefore, when an external force is applied to lock the supported member, the second link member swings in conjunction with the supported member. Since the third link member is fixed, the swing of the second link member causes the first link member to expand and contract between the second link member and the third link member. Since the first link member stores the resilient force in the urging means by the displacement, the resilient force acts as a reaction force of the locking and acts in the direction of returning the supported member to the original position.

Here, when adjusting the magnitude of the reaction force when locking the supported member, the fixing position of the third link member is changed by operating the adjusting screw. Thereby, the second
Since the angle formed between the link member and the third link member is changed, the initial length of the first link member and the biasing angle with respect to the second link member change simultaneously. Therefore, the initial length and the urging angle of the first link member can be changed at the same time, so that the adjustment can be made in comparison with the conventional reaction force adjusting mechanism in which only one of the initial length and the urging angle of the urging means is changed. The change amount of the reaction force with respect to the operation amount of the screw can be increased.

According to a second aspect of the present invention, in the chair supporting mechanism of the first aspect, the first link member, the second link member, and the third link member are connected to each other by the movement of the third link member. As the member compresses, an urging angle θ formed by the urging direction of the first link member with respect to a straight line connecting the rotation center of the connecting portion between the first link member and the second link member and the rotation center of the second link member. Is installed so as to approach at right angles.

Therefore, when adjusting the reaction force of the locking, the change of each locking reaction force due to the change of the initial length and the biasing angle θ of the first link member is made to coincide with either increase or decrease. Can be. For this reason, the changes in the respective locking reaction forces due to the change in the initial length and the biasing angle θ of the first link member do not cancel each other, so that the amount of change in the reaction force with respect to the operation amount of the adjusting screw can be increased. it can.

Further, the invention according to claim 3 is the invention according to claim 1.
Or the chair support mechanism according to 2, wherein a rear seat forming a rear portion of a seat as a supported member swingably supported at a front end side with respect to a seat receiving member as a support member, and a front portion of the seat. A front seat, a sliding means for supporting the front seat on the seat receiving member so as to be able to move back and forth, and a connecting means for connecting the rear end of the front seat and the front end of the rear seat. I have.

Therefore, when the seated person tilts the backrest or the seat rearward from the original position, the rear seat swings so as to sink backward around the center of rotation on the front end side. The front end moves backward without lifting. Then, the rear seat is moved by pulling the front seat rearward while tilting backward.
Also, the rear seat is moved by pushing the front seat forward while returning to the original position. Here, since the front seat is supported by the seat receiving member by the sliding means so as to be able to move back and forth, it is possible to suppress an elevation of the front portion of the seat when the seat is tilted backward. For this reason, it is possible to prevent compression of the thigh of the seated person and prevent the leg of the seated person from being lifted off the floor by lifting the thigh of the seated person.

In the chair supporting mechanism according to the fourth aspect, the sliding means lowers the front seat moving rearward and raises the front seat moving forward.
Therefore, when the seated person tilts the seat backward, the front portion of the seat is lowered, so that the pressure on the thighs of the seated person can be prevented, and the thighs of the seated person are lifted, and the legs of the seated person are raised on the floor. Can be prevented from leaving.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on an example of an embodiment shown in the drawings. As shown in FIGS. 1 to 5, the chair support mechanism 1 of the present embodiment is configured to rockably support a rear seat 3 as a supported member with respect to a seat receiving member 2 as a support member. .

The support mechanism 1 is provided with an urging means 5 for storing a resilient force by displacement, and is provided with an extendable first link member 4.
And the second link member 14 which swings in conjunction with the rear seat 3
And a third link member 11 to be fixed.
By making the fixing position of the third link member 11 movable by the adjusting screw 12, the magnitude of the reaction force of the locking of the rear seat 3 can be adjusted. Here, the second link member 14
One end of each of the first link member 4 and the third link member 11 is rotatably connected, and the other end of the first link member 4 and the third link member 11 are rotatably connected to each other. The members 4, 14, and 11 constitute a restricted rotation chain. Therefore, by operating the adjusting screw 12, the third
By changing the fixing position of the link member 11, the second
Since the angle between the link member 14 and the third link member 11 is changed, the initial length of the first link member 4 and the urging angle θ with respect to the second link member 14 can be changed simultaneously. Therefore, the amount of change in the locking reaction force with respect to the amount of operation of the adjusting screw 12 can be increased.

The first link member 4 includes an urging means 5, a front spring mount 7 for supporting a front end of the urging means 5, and a rear spring mount 8 for supporting a rear end of the urging means 5. Have. As the urging means 5, as shown in FIG. 2, two compression coil springs are installed inside the seat receiving member 2 in parallel with the front and rear sides as longitudinal directions. In this embodiment, a compression coil spring is used as the urging means 5, but the present invention is not limited to this. For example, a gas spring or the like may be used.

The front spring mount 7 is connected to the second link member 1.
4 is rotatably connected to a support shaft 16. The rear spring mount 8 is rotatably connected to the third link member 11 by the support shaft 6. The rear spring mount 8 is formed with a guide shaft 9 protruding toward the front spring mount 7. Further, a guide hole 10 for slidably receiving the guide shaft 9 is formed in the front spring mount 7. For this reason, each of the mounts 7 and 8 can be approached or separated from each other while holding and holding the urging means 5 and receiving the elastic force of the urging means 5.

The rear seat 3 includes a rear seat plate 13 for receiving a cushion (not shown), and a second link member 14 fixed to a front portion of the rear seat plate 13. The second link member 14 is rotatably connected to the seat receiving member 2 by a locking shaft 15. The second link members 14 are L-shaped, and are provided on both left and right sides inside the seat receiving member 2. When the rear seat plate 13 is made horizontal,
As shown in FIG. 3, one side of the second link member 14 is horizontal and the other side is vertical. As a result, the locking shaft 15 is disposed below the front portion of the rear seat 3, so that the height of the rear seat 3 is the highest in the basic posture in which the seat is horizontally supported as shown in FIG. As the rear seat 3 tilts rearward, the rear seat 3 can move rearward while sinking its front end. As a result, the seat sinks when the body sinks behind, so that the thighs are not pressed and the feet can be removed from the floor.

Further, the third link member 11 has a rocking shaft 1 whose one end serves as a rotation center of the second link member 14.
By being supported by 5, it is rotatably connected to both the seat receiving member 2 and the second link member 14. Here, the third link member 11 is pushed down via the support shaft 6 by the elastic force of the urging means 5 attached to the first link member 4 at the other end connected to the first link member 4. I have. For this reason, the bearing groove 21 at the lower part of the third link member 11 is pressed and fixed to the lifting rod 19. In the present embodiment, one end of the third link member 11 is connected to the seat receiving member 2 and the second link member 14 so as to be rotatable at the same time. However, the present invention is not limited to this. By being connected to the second link member 14 or the seat receiving member 2, it may be rotatably connected to only one of the seat receiving member 2 or the second link member 14. If the first link member 4, the second link member 14, and the third link member 11 can form a restricted rotation chain, the first link member 4, the second link member 14, and the third link member 11 are rotatably connected to members other than the seat receiving member 2 and the second link member 14. Is also good. In any case, by operating the adjusting screw 12 to change the fixed position of the third link member 11, the initial compression length of the first link member 4 and the second link member 14 are changed.
Can be changed at the same time, the amount of change in the locking reaction force with respect to the amount of operation of the adjusting screw 12 can be increased.

In the support mechanism 1, the first link member 4, the second link member 14, and the third link member 11 are moved by the movement of the third link member 11, as shown in FIGS. 4 as the first link member 4
And the urging direction of the first link member 4 with respect to a straight line C2 connecting the rotation center of the connection portion of the second link member 14 (ie, the support shaft 16) and the rotation center of the second link member 14 (ie, the locking shaft 15). The bias angle θ formed by C1 is set to be close to a right angle. For this reason, when adjusting the reaction force of the locking, the change of each locking reaction force due to the change of the initial compression length of the first link member 4 and the biasing angle θ is made to coincide with either the increase or the decrease. Therefore, the amount of change in the reaction force with respect to the operation amount of the adjustment screw 12 can be increased.

In this embodiment, as shown in FIG. 4, when the third link member 11 is located at the uppermost position, a straight line C2 connecting the locking shaft 15 and the support shaft 16 and the first link member 4
The biasing angle θ formed by the center line C1 of FIG. The rotatable range of the third link member 11 is set to about 15 degrees. That is, the urging angle θ of the first link member 4 described above is, for example, from about 75 degrees shown in FIG.
Can be changed within the range of about 90 degrees. When the urging angle θ of the first link member 4 is set to be larger than about 90 degrees, the third link member 11 comes into contact with a stopper (not shown) so as not to rotate any more. If the urging angle θ of the first link member 4 is to be made smaller than about 75 degrees, the lifting rod 19 will not fall below that, and the first link member 4 is prevented from rotating further.

Thus, when the third link member 11 is located at the uppermost position as shown in FIG. 4, the urging means 5 is most compressed and the urging direction of the urging means 5 is changed to the second link member. Since the rotation direction is substantially the same as the rotation direction of the second link member 14, the reaction force to the second link member 14 is maximized. On the other hand, when the third link member 11 is located at the lowermost position as shown in FIG. 1, the urging means 5 is most extended, and at the same time, the urging direction of the urging means 5 is the rotational direction of the second link member 14. , The reaction force on the second link member 14 is minimized.

In this embodiment, when the third link member 11 is positioned at the uppermost position, the biasing angle θ of the first link member 4 is made substantially a right angle, and the rotatable range of the third link member 11 is approximately Although the angle is set to 15 degrees, it is a matter of course that the angle is not limited to 15 degrees. Even if the urging angle θ and the rotatable angle of the third link member 11 are set to other values, the initial compression of the first link member 4 is changed by operating the adjustment screw 12 to change the fixed position of the third link member 11. Length and second link member 1
4, the amount of change in the locking reaction force with respect to the amount of operation of the adjusting screw 12 can be increased.

The adjusting screw 12 is located directly below the third link member 11, penetrates from the outside to the inside of the seat receiving member 2, and is rotatably mounted. The adjusting screw 12 has a screw portion 17 protruding inside the seat receiving member 2 and a grip 18 outside the seat receiving member 2. A screw hole 20 formed at the center of the lifting rod 19 is screwed into the screw portion 17. The elevating rod 19 has a left-right direction as a longitudinal direction.
A screw hole 20 penetrating vertically is provided at the center, and the third link member 11 is pushed up from below and fixed.
As shown in FIG. 3, bearing grooves 21, 21 which are slightly longer in the front and rear than the diameters of both ends 22, 22 of the lifting rod 19 are formed in the center of the lower edges of the left and right of the third link member 11. Both ends 22, 22 of the lifting rod 19 are accommodated in left and right bearing grooves 21, 21 of the third link member 11, respectively. Therefore, when the occupant rotates the grip 18 of the adjusting screw 12, the screw portion 17 rotates to move the lifting rod 19 up and down. As a result, the third link member 11 rotates about the locking shaft 15 to change the urging angle θ of the urging means 5 and the initial compression length. Therefore, the locking reaction force of the second link member 14 can be adjusted.

At this time, with the swing of the third link member 11, both ends 22, 22 of the elevating rod 19 are moved to the third link member 1.
It slides back and forth inside one of the bearing grooves 21 and 21. As a result, the end portions 22 and 22 are not fixed back and forth with respect to the bearing grooves 21 and 21, and the swing of the third link member 11 is not hindered by these interferences.

On the other hand, the support mechanism 1 of this chair
A front side seat 23 provided on the front side of the front side to form a front portion of the seat;
The front seat 23 includes a sliding means 34 for supporting the seat member 2 so as to be able to move back and forth, and a connecting means 29 for connecting the rear end of the front seat 23 and the front end of the rear seat 3. That is, the chair supporting mechanism 1 performs so-called double rocking with different inclination angles before and after the seat when rocking. The front seat 23 includes a front seat plate 24 that supports a cushion (not shown) from below, and a sliding member 25 fixed to the front seat plate 24. The cushion supported by the front seat plate 24 and the cushion supported by the rear seat plate 13 are continuous without any gap.

The connecting means 29 comprises a shaft for rotatably connecting the rear part of the sliding member 25 and the second link member 14.
Therefore, when the second link member 14 is inclined rearward, the connecting means 29 pulls the front seat 23 rearward and moves it. When the rearwardly inclined second link member 14 returns to the original position, the connecting means 29 pushes the front seat 23 forward to move it. In the present embodiment, the connecting means 29 is a shaft for rotatably connecting the rear portion of the sliding member 25 and the second link member 14, but is not limited to this. It is also possible to fix the engaging shafts projecting to the left and right to the second link member 14 and slidably fit the engaging holes with the engaging shafts. In this case, when the rear seat 3 is inclined backward, the engaging shaft is hooked on the rear end of the long hole to move the front seat 23 to the rear side, and when the rear seat 3 returns to the original position, the rear The cushion attached to the side seat 3 presses the cushion attached to the front seat 23 to the front side to push the front seat 23 forward to move.

The sliding means 34 is attached to the front part of the sliding member 25 and is formed at the front end of each of the side walls 2a, 2a of the seat receiving member 2 and the front support shaft 26 projecting right and left. A front support hole 27 whose longitudinal direction is the front and rear. The front support hole 27 is inclined with the front side up and the back side down. Both ends of the front support shaft 26 are slidably supported by the front support holes 27, 27. For this reason, when the front seat 23 moves to the front side, the front part rises, and when the front seat 23 moves to the rear side, the front part falls. This can suppress the rise of the front seat 23 when the rear seat 3 is tilted backward, so that it is possible to prevent pressure on the thighs of the seated person and also prevent the seated person's legs from separating from the floor.

Here, the inclination angle of the front support hole 27 is the arc of the arc drawn when the connecting means 29 moves from the uppermost position shown in FIG. 1 to the lowermost position shown in FIG. It is made to be almost parallel to the trajectory. For this reason, even if the connecting means 29 moves from the uppermost position shown in FIG. 1 to the lowermost position shown in FIG. 5 due to the backward inclination of the second link member 14 and the rear part of the front seat 23 descends, the front part of the front seat 23 Fall by the same amount, the front seat 23 descends while substantially maintaining the horizontal state. This can prevent the front seat 23 from pushing up and pressing the back side of the seated person's thigh, and prevent the feet from separating from the floor, thereby not giving an unstable feeling.

In the present embodiment, the inclination angle of the front support hole 27 is set to be substantially parallel to the locus of the arc between the uppermost position and the lowermost position of the connecting means 29. However, the present invention is not limited to this. The angle of inclination of the support hole 27 may be made larger than the above-described arc locus. In this case, when the front seat 23 moves rearward, the front seat 23 descends more greatly than the rear side of the front seat 23. Therefore, when the rear seat 3 is tilted backward, the front seat 23
Leans forward. Therefore, also in this case, it is possible to prevent the front seat 23 from pushing up the back side of the thigh of the seated person. further,
The inclination angle of the front support hole 27 may be inclined more horizontally than the above-mentioned arc locus, for example, horizontally. In this case, when the rear seat 3 tilts rearward, the front seat 23 also tilts rearward. Therefore, also in this case, it is possible to prevent the front seat 23 from pushing up the back side of the thigh of the seated person.

On the other hand, a gas damper 30 is mounted between the rear end of the rear seat 3 and the rear end of the seat receiving member 2. A backrest (not shown) is provided on the rear side of the rear seat 3. This backrest is linked to the locking of the rear seat 3. The backrest and the rear seat 3 are integrated so as to be inclined at the same angle, or a so-called synchro mechanism is used to maintain the inclination angle of the backrest and the inclination of the rear seat 3 so as to maintain a constant relationship. You may do it. The gas damper 30 is a gas spring that permits or locks the rod in and out of the cylinder by opening and closing a valve to make the entire length extendable and contractable at an arbitrary position. Therefore, the gas damper 30
The opening and closing operation allows the backrest and the seat to be fixed or tilted at an arbitrary position. That is, if the gas damper 30 is free, when the seated person leans on the backrest, the backrest and the rear seat 3 are inclined against the urging means 5. When the seated person stops applying his weight, the backrest and the rear seat 3 return to the original position by the urging force of the urging means 5.
On the other hand, if the gas damper 30 is locked, the seat receiving member 2
And the rear seat 3 and the gas damper 30 form a fixed chain, and the seat and the backrest cannot tilt.

At the end of the gas damper 30 attached to the seat member 2, there is provided an adjusting lever 32 for pressing the operating pin 31 of the gas damper 30 to open and close the valve of the gas damper 30, and an operating mechanism (not shown) thereof. Is provided.
Therefore, the locking and free of the gas damper 30 can be controlled by operating the operating mechanism.

Further, the seat receiving member 2 is supported by a pillar (not shown). The periphery of the seat receiving member 2 is covered by a cover member 33.

When the above-described chair support mechanism 1 is used, the seated person can perform the rocking by leaning the backrest with his / her weight. At this time, the rear seat 3
When an external force is applied to lock the second member, the second link member 14 swings in conjunction with the rear seat 3. And the third
Since the link member 11 is fixed, the swing of the second link member 14 causes the first link member 4 to expand and contract between the second link member 14 and the third link member 11. Further, the resilient force accumulated by the displacement of the first link member 4 acts as a reaction force of the locking and acts in a direction to return the rear seat 3 to the original position. Thereby, locking can be performed.

Here, as the second link member 14 of the rear seat 3 is tilted backward, the front seat 23 moves rearward while descending.
For this reason, it is possible to prevent the back side of the thigh of the seated person from being pressed and the legs from being lifted off the floor.

When the grip 18 is rotated, the lifting rod 19 is moved up and down to rotate the third link member 11. For this reason, the initial compression length of the first link member 4 and the second compression
Since the biasing angle θ with respect to the link member 14 is changed at the same time, the reaction force of the rearward tilt of the rear seat 3 can be greatly changed with respect to the operation amount of the adjusting screw 12.

According to the chair support mechanism 1 of the present embodiment, the initial compression length of the first link member 4 and the attachment to the second link member 14 are adjusted in order to adjust the reaction force of the rear seat 3 to tilt backward. Since the urging angle θ is changed at the same time, the reaction force with respect to the operation amount of the adjusting screw 12 is smaller than that of the conventional chair supporting mechanism in which only one of the initial compression length of the urging spring and the urging angle is changed. The amount of change can be increased. Therefore, when the operable range of the adjusting screw 12 is the same as the conventional range, the range in which the locking reaction force can be changed can be widened. Further, in order to change the reaction force by a fixed amount, the operation amount of the adjusting screw 12 can be reduced as compared with the conventional case, or the operation amount can be made equal to the conventional case to reduce the operation force. Therefore, the operability in adjusting the reaction force can be improved.

Further, since the initial compression length of the urging means 5 is changed, the initial pressure for locking can be adjusted. Thereby, the usability of the chair can be improved.

Since the position of the bearing groove 21 in which the lifting rod 19 is engaged with the third link member 11 is located at the center of the third link member 11 in the front-rear direction, the stroke of the support shaft 6 is limited to the length of the lifting rod 19. Approximately twice the stroke. For this reason, a large rotation angle of the third link member 11 can be obtained with a small operation of the adjusting screw 12, so that the operability in adjusting the reaction force can be improved.

Furthermore, according to the chair support mechanism 1 of the present embodiment, the front seat 23 moves rearward while descending as the second link member 14 of the rear seat 3 is tilted backward, so that the seated person Pressing the back of the thigh and lifting the leg from the floor can be prevented. For this reason, it is possible to eliminate the uncomfortable feeling when the occupant rocks and improve the sitting comfort.

Although the above embodiment is an example of a preferred embodiment of the present invention, the present invention is not limited to this embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, the support mechanism 1 supports the rear seat 3 with respect to the seat receiving member 2. However, the present invention is not limited to this. For example, the support mechanism 1 may support the backrest with respect to the seat receiving member 2 or the seat. Can be applied. In the present embodiment, the support mechanism 1 is mounted on a chair capable of double locking. However, the present invention is not limited to this, and the support mechanism 1 may be mounted on a chair that performs normal locking. Also in this case, the initial compression length of the first link member 4 and the second compression
By simultaneously changing the urging angle θ with respect to the link member 14, the operability in adjusting the reaction force can be improved.

[0044]

As is apparent from the above description, according to the chair of the first aspect, one end of the first link member and the third link member are rotatably connected to the second link member. Since the other ends of the link member and the third link member are rotatably connected to each other to form a constrained rotation chain, the adjusting screw is operated to simultaneously change the initial length and the inclination angle θ of the first link member. By doing so, the reaction force when locking the supported member can be adjusted. This allows
The amount of change in the reaction force with respect to the operation amount of the adjusting screw can be increased as compared with a conventional reaction force adjusting mechanism that changes only one of the compression length and the urging angle of the urging spring. Therefore, when the operable range of the adjusting screw is the same as the conventional range, the range in which the locking reaction force can be changed can be widened. Further, in order to change the reaction force by a certain amount, the operation amount of the adjusting screw can be reduced as compared with the conventional case, or the operation amount can be made equal to the conventional case to reduce the operation force. Therefore, the operability in adjusting the reaction force can be improved.

In addition, since the initial length of the biasing spring is changed, the initial pressure of locking can be adjusted. Therefore, the feeling of use of the chair can be improved.

In the chair support mechanism according to the second aspect, as the first link member is compressed by the movement of the third link member, the rotation center of the connecting portion between the first link member and the second link member is moved to the second position. Since the urging angle θ formed by the urging direction of the first link member is made closer to a right angle with respect to a straight line connecting the rotation center of the link member, the initial compression length and the urging angle θ of the first link member are set. The change in the respective rocking reaction force due to the change in can be made to coincide with either increase or decrease. For this reason, since the changes in the respective rocking reaction forces due to the change in the initial compression length and the biasing angle θ of the first link member do not cancel each other, the change amount of the reaction force with respect to the operation amount of the adjusting screw is increased. Can be.

Further, in the chair supporting mechanism according to the third aspect, the rear seat forming the rear portion of the seat as the supported member that is swingably supported at the front end side with respect to the seat receiving member as the supporting member. A front seat forming a front portion of the seat, sliding means for supporting the front seat on the seat receiving member so as to be movable back and forth, and connecting means for connecting a rear end of the front seat and a front end of the rear seat. , The elevation of the front portion of the seat when the seat is tilted backward can be suppressed. For this reason, it is possible to prevent pressure on the thighs of the occupant at the time of rocking and also prevent the feet from coming off the floor and giving an unstable feeling. Therefore, it is possible to eliminate a sense of incongruity when the seated person locks the seat or the backrest, thereby improving the sitting comfort of the chair.

Further, in the chair supporting mechanism according to the fourth aspect, the sliding means lowers the front seat moving rearward and raises the front seat moving forward, so that the compression of the thigh of the seated person is suppressed. In addition, it is possible to prevent the thighs of the occupant from being lifted and the legs from coming off the floor. Therefore, it is possible to eliminate a sense of incongruity when the seated person locks the seat or the backrest, thereby improving the sitting comfort of the chair.

[Brief description of the drawings]

FIG. 1 is a central longitudinal sectional view showing a state where a seat is in an original position when a rocking reaction force of a support mechanism of a chair of the present invention is minimum.

FIG. 2 is a plan view showing a chair support mechanism.

FIG. 3 is a side view showing a main part of the chair support mechanism shown in FIG. 1;

FIG. 4 is a central longitudinal sectional view showing a state where a seat is in an original position when a rocking reaction force of a support mechanism of a chair is maximum.

FIG. 5 is a central longitudinal sectional view showing a state where the seat is tilted rearward when the rocking reaction force of the support mechanism of the chair is minimum.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 chair support mechanism 2 seat receiving member (support member) 3 rear seat (supported member) 4 first link member 5 urging spring 6 reaction force adjusting mechanism 11 third link member 12 adjusting screw 14 second link member 15 Locking shaft 23 Front seat 29 Connecting means 34 Sliding means

Claims (4)

[Claims] 1. A supporting mechanism for a chair for supporting a supported member in a rockable manner with respect to a supporting member, wherein the first link member is provided with an urging means for storing a resilient force by displacement, and is expandable and contractable; A second link member that swings in conjunction with the member, and a third link member that is fixed;
One end of the first link member and the third link member is rotatably connected to the link member, and the other end of the first link member and the third link member are rotatably connected to each other. And a magnitude of a reaction force of locking of the supported member can be adjusted by making a fixed position of the third link member movable by an adjusting screw. 2. The first link member, the second link member, and the third link member, wherein the first link member and the third link member are compressed as the first link member is compressed by the movement of the third link member. An urging angle θ formed by the urging direction of the first link member with respect to a straight line connecting the rotation center of the connecting portion of the second link member and the rotation center of the second link member.
2. The support mechanism for a chair according to claim 1, wherein the support mechanism is installed so as to approach the right angle. 3. A rear seat forming a rear portion of the seat as the supported member swingably supported at a front end side with respect to the seat receiving member as the support member, and a front portion of the seat is formed. A front seat, a sliding means for supporting the front seat on the seat receiving member so as to be able to move back and forth, and a connecting means for connecting a rear end of the front seat and a front end of the rear seat. The chair support mechanism according to claim 1 or 2, wherein: 4. The chair supporting mechanism according to claim 3, wherein said sliding means lowers said front seat moving rearward and raises said front seat moving frontward.