JPH0440531Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a chair in which the elastic biasing force of the back plate changes depending on the weight of the seated person.

[Conventional technology]

Conventional chairs with backrests that tilt back and forth have a backrest rod that connects the backrest plate to the upper end and is pivoted to the underside of the seat, and the backrest rod is always forward in order to support the seated person's backward tilt. The backrest lever is elastically biased in the direction of tilting by a coil spring, and the strength of the spring is adjusted depending on the seated person. Since the tilting angle of the device varies greatly, it is necessary to adjust the strength of the spring each time, which poses a problem when used by an unspecified number of people. In addition, chairs that have an elastic body embedded inside the backrest rod or seat that elastically supports the backrest plate are adjusted to standard specifications when shipped from the factory, and it is impossible for the seater to adjust them from the outside. It still had the problems mentioned above. Therefore, the chair has a backrest plate whose resistance to tilting backwards changes depending on the weight of the seated person, that is, the resistance force against tilting backwards is large for a heavy seated seater, and the resistance against backward tilting is large for a seated seated person who is light in weight. It was hoped that a chair would be made smaller.

[The problem that the idea attempts to solve]

In view of the above-mentioned situation, the present invention aims to solve the problem by automatically setting the elastic resistance against the backward tilting of the backrest plate based on the weight that the seat plate receives when the seated person is seated on the seat plate, To provide a chair that maintains a set state even when the weight is dispersed while leaning on a backrest plate and the weight received by a seat plate is reduced, and returns to the initial state when the seat is left.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention is a seat that has its front part pivoted to a frame attached to the upper end of the pedestal using a fixed support shaft, and its rear part supported by the frame via a compression coil spring. a plate, a backrest rod which is pivoted on a fixed support shaft with a lower end left on the frame, an arm protruding forward from the pivot, and a backrest plate attached to the upper part; and a short diameter side. A cam having notches formed at predetermined intervals around the periphery of the frame is pivotally supported in the frame by a support shaft, and the eccentric position of the cam and the rear part of the seat plate are hingedly connected to each other by a transmission rod. A central portion of a latch having a pawl that engages with the notch is pivoted within the frame and is elastically biased in the direction of engagement, and the other end is brought into contact with the arm against the elastic biasing force to effect engagement. In the released state, one end is pivoted to the lower end of the backrest rod by a floating support shaft, and one end is attached to a guide rod having an oval ring provided at the other end loosely fitted to the support shaft of the cam. A chair is constituted by a tilt adjustment device in which a compression coil spring that is in sliding contact around the cam is compressed and wound to elastically urge the upper part of the backrest rod forward.

[Effect]

In the chair of the present invention having the above-mentioned features, when a person sits on the seat plate, the rear part of the seat plate sinks against the elastic force of the first compression coil spring, and is hinged to the seat plate. The transmission rod rotates the cam, which compresses the second compression coil spring interposed between the lower end of the backrest rod and the periphery of the cam, increasing the resistance force against the backward tilting of the backrest rod. When you lean on the backrest rod, you lean backwards against the elastic force of the second compression coil spring, the tip of the arm separates from the latch, and the claw at the tip engages with the notch of the cam due to the elastic biasing force, causing the cam to move. Regulation of rotation, resistance to backward tilting of the backrest rod according to the weight of the seated person,
That is, the second compression coil spring is compressed in advance to maintain the preset initial elastic force. As the backrest lever leans back, the repulsive force of the second compression coil spring increases as in a normal chair, and at this time, the oval ring of the guide rod moves along the support shaft of the cam, causing the backrest to tilt back. This absorbs changes in the distance between the lower end of the leaning rod and the cam.

〔Example〕

Next, the present invention will be further explained in detail based on the embodiments shown in the accompanying drawings.

FIG. 1 shows a typical embodiment of the chair of the present invention,
In the figure, 1 is the frame, 2 is the seat plate, 3 is the backrest lever, 4
1 and 2 respectively indicate tilt adjustment devices.

The frame 1 is rotatably or non-rotatably attached to an ordinary foot stand 5, and in this embodiment is formed of a shell-like box with an open top.

The seat plate 2 rotatably supports a support piece 6 provided on the front part of the lower surface of the frame 1 on a fixed support shaft 7, and a support piece 6 provided on the rear part of the lower surface is rotatably supported on the front part of the frame 1. The upper ends of one compression coil spring 9 are connected, and the lower ends are supported by a support plate 10 fixed within the frame 1 to elastically support the weight of the seated person. In addition, in order to ensure the compression of the first compression coil spring 9,
In this embodiment, a support 11 consisting of a connecting part and a guide rod that pivots on the support piece 8 is used, and the guide rod of the support 11 is inserted into the spring 10, and a hole articulated in the support plate 10 is used. 12 is loosely inserted.

The backrest rod 3 is pivoted in the frame 1 on a fixed support shaft 14 so as to be tiltable back and forth, with a lower end 13 remaining. A backrest plate 16 is attached, and a stopper 17 fixed to the frame 1 is stopped at an appropriate position on the backrest rod 3 in order to prevent forward inclination beyond a set angle.

The tilt adjustment device 4 includes a cam 19 rotatably supported in the frame 1 by a support shaft 18, and a cam 19 that adjusts the downward displacement of the seat plate 2 according to the weight of the seated person applied to the seat plate 2. A transmission rod 20 that transmits information to the cam 19, a latch 21 that is operated by the arm 15 and restricts the rotation of the cam 19 at a predetermined rotation angle, and a guide rod 2 between the lower end 13 of the backrest rod 3 and the cam 19.
2, and a second compression coil spring 23 that elastically urges the backrest lever 3 in a forward tilting direction. The cam 19 has a disk shape with a partially bulged shape, and gear-shaped notches 24 are formed at predetermined intervals around the short diameter side, and the horizontal support shaft 18
It is designed to rotate in a vertical plane. Then, a position eccentric from the support shaft 18 of the cam 19 and the rear part of the seat plate 2, in this embodiment, a suitable position of the bulge below the support shaft 18 and the support piece 8 at the rear of the seat plate 2 are transmitted. They are hingedly connected to each other by a rod 20. The latch 21 has a pawl 25 at one end that can engage with the notch 24 of the cam 19, and its central portion is pivoted within the frame 1, and a spring 26 engages the pawl 25 with the notch 24. It is elastically biased in the direction of engagement, and the upper end of the other end is brought into contact with the tip of the arm 15. In the initial unloaded state when the backrest rod 3 is in contact with the stopper 17, The arm 15 holds the latch 21 against the spring 2.
The claw 25 at the tip is rotated against the elastic biasing force of 6.
, and the engagement between the claw 25 and the notch 24 is released. Further, the guide rod 22 has a connecting portion 28 at one end that is pivotally supported on the lower end 13 of the backrest rod 3 by a floating support shaft 27, and the cam 19 at the other end.
It has an elongated ring 30 formed in the longitudinal direction with an elongated hole 29 which is slidably and loosely fitted into the support shaft 18 which is pivotally supported. A ring 31 is slidably fitted loosely therein, and the second compression coil spring 23 is compressed and wound between the connecting portion 28 and the sliding ring 31.

Therefore, in the chair of the present invention, in the unloaded initial state shown in FIG. the latch 21 is rotated by the arm 15 against the elastic biasing force of the spring 26, and the claw 25 at the tip and the notch 24 of the cam 19 are completely separated, and the cam 19 is free. It is in a state where it can be rotated. Therefore,
As shown in FIG. 2, when a person sits on the seat plate 2, the rear part of the seat plate 2 sinks depending on the weight of the seated person, but in this case, the elastic force of the first compression coil spring 9 and the seat plate 2
Until the position is balanced with the elastic force due to the compression of the second compression coil spring 23 interposed between the cam 19 which rotates in conjunction with the displacement of the backrest rod 3, that is, the one-dot chain line in the figure. The seat plate 2 will sink from the state shown by the solid line to the state shown by the solid line. In this state, as described above, the seat plate 2 is
The cam 19 rotates by an angle corresponding to the weight of the seated person, whereby the sliding ring 31 slidingly contacts the outer peripheral surface of the cam 19 in the direction of the lower end 13 of the backrest rod 3. , the second compression coil spring 23 is compressed, and the resistance force against the backward tilting of the backrest lever 3 increases in accordance with the weight. In this way, when the seated person leans against the backrest rod 3, that is, the backrest plate 16, with the initial resistance force against the backward tilting of the backrest rod 3 depending on the weight of the seated person, the backrest will tilt. As the rod 3 tilts backward, the tip of the arm 15 rises, and the claw 25 at the tip of the latch 21 lowers. Eventually, when the backrest rod 3 tilts slightly backward by a predetermined angle, the claw 25 engages the notch of the cam 19. 24, the rotation of the cam 19 is restricted, and the initial resistance force is maintained. Then, if you lean further on the backrest plate 16, the backrest rod 3 will tilt backward against the second compression coil spring 23.
The arm 15 is completely separated from the latch 21, and the lower end 13 is displaced forward to push out the guide rod 22, and the elongated hole 29 of the oval ring 30 of the guide rod 22 slides along the support shaft 18. As a result, changes in the distance between the cam 19 and the lower end portion 13 of the backrest rod 3 are absorbed. In this way, even if the weight applied to the seat plate 2 decreases when the seated person leans back on the backrest plate 16, the backrest is automatically set according to the net weight before the seated person leans back on the backrest plate 16. The elastic biasing force is always maintained.

Moreover, the chair shown in FIG. 4 is another embodiment of the present invention, and the same constituent members as in the previous embodiment are given the same numbers and their explanations will be omitted. Here, to explain only the differences, a rotary body 32 having a notch 24 around a part thereof is used instead of the cam 19,
A coil spring 33 is pulled at a suitable position above the backrest rod 3 which pivotally supports the rotating body 32 and the lower end 13 on the frame 1.
This is a combination of inquiries and connections.

[Effect of idea]

According to the chair of the present invention constructed as described above, the seat plate and the backrest lever are linked to each other, and the elastic biasing force against the backward tilt of the backrest lever is automatically applied depending on the weight of the seated person on the seat plate. Moreover, even if the weight of the seated person is distributed between the seat plate and the backrest plate, and the weight applied to the seat plate is reduced, the weight of the occupant before leaning on the backrest plate is reduced. The weight applied to the seat plate at the beginning of the process sets the resistance force against the backward tilting of the backrest rod, and this state can be maintained constant regardless of the degree to which you lean against the backrest plate. As mentioned above, the weight applied to the seat plate is set based on the net initial weight applied to the seat plate rather than the apparent weight of the seated person who is distributed, so the weight applied to the seat plate changes greatly when seated persons with widely different body weights use the seat. In addition, even if the seated person changes their sitting posture significantly, it increases the sense of stability when leaning against the backrest plate, and allows the seated person to sit with good balance. Not only does the backrest plate not tilt extremely backwards unexpectedly and give a sense of instability to the seated person, as in the case of the seatback, it also does not turn around afterwards.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal side view showing a typical embodiment of the present invention, FIG. 2 is a longitudinal side view of the seat seated on the seat board,
FIG. 3 is a longitudinal side view of the user seated on the seat plate and leaning against the backrest plate, and FIG. 4 is a longitudinal side view showing another embodiment. DESCRIPTION OF SYMBOLS 1... Frame, 2... Seat plate, 3... Backrest rod, 4... Tilt adjustment device, 5... Leg stand, 6... Support piece, 7... Fixed support shaft, 8... Support piece, 9... First compression coil spring, 10... Support plate, 11... Support tool, 12... Hole, 13... Lower end, 14... Fixed support shaft, 15... Arm, 16... Backrest plate ,1
7... Stopper, 18... Support shaft, 19... Cam, 20... Transmission rod, 21... Latch, 22...
Guide rod, 23... Second compression coil spring, 24...
Notch, 25... pawl, 26... spring, 27... floating support shaft, 28... connecting portion, 29... long hole, 30...
...Oval ring, 31...Sliding ring, 32...Rotating body, 33...Tension coil spring.

Claims (1)

[Claims for Utility Model Registration] A seat plate whose front part is pivotally supported by a fixed support shaft to a frame attached to the upper end of the leg stand, and whose rear part is supported by the frame via a first compression coil spring. , a backrest rod which is pivoted on a fixed support shaft with a lower end left on the frame, an arm protruding forward from the pivot, and a backrest plate attached to the upper part; and the periphery of the short diameter side. A cam having notches formed at predetermined intervals is pivotally supported in the frame by a support shaft, and the eccentric position of the cam and the rear part of the seat plate are hingedly connected to each other by a transmission rod, and the notches are formed at one end. A central portion of a transmission rod having a pawl that engages with the frame is pivoted within the frame and is elastically biased in the direction of engagement, and the other end is brought into contact with the arm against the elastic biasing force to release the engagement. In addition, one end is pivoted to the lower end of the backrest rod by a floating support shaft, and one end is attached to a guide rod having an oval ring provided at the other end loosely fitted to the support shaft of the cam. A chair comprising: a tilt adjustment device configured by compressing and winding a second compression coil spring in sliding contact around the cam to elastically urge the upper part of the backrest rod forward.