JPS63277012A - Chair - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) This invention relates to a chair that does not require adjustment of the movement of the backboard and seat even if the weight of the person sitting on it changes.

(Prior art and its problems) In the conventional chair, the structure for tilting the back plate is as follows.
It is biased in the upright direction by a spring. For this reason,
A certain amount of force is required to tilt the backboard.

Therefore, in order to tilt the backboard, it is necessary to apply a certain amount of force regardless of the physique of the person sitting on the chair, so for a person who is one weight light, it is necessary to apply the entire body weight of the person and apply additional force to the back. It is necessary to push down the board. Also,
Heavy people have problems such as the back plate easily tilting when they put their whole weight on it.

Therefore, in this invention, the force for tilting the backboard changes depending on the physique of the person sitting. That is, the object is to provide a chair that has a tilting repulsion force that is appropriate for the user's physique.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes the following configuration.

That is, the bottom part (horizontal arms 21a, 21b) of the back frame 20, which supports the back plate 19 and has a substantially L-shaped lateral shape, extends below the seat part 26, and the bottom part (horizontal arms 21a, 21
b) A support frame 15 whose midway portion is fixed to the upper end of the pedestal 12
The back frame 20
One end of the link plate 28 is pivoted rearward from the center of rotation of the link plate 28, and the other end of the link plate 28 is pivoted to the seat portion 26 so that the link plate 28 is tilted rearward. In order to move the seat part 26 forward when rotating rearward about the center of movement, the bottom part of the back frame 20 (horizontal arms 21a, 21b)
) is characterized in that the tip thereof is connected to the seat portion 26.

(effect) Next, the operation of this invention will be described.

When the user rests on the back plate 19, the back frame 20 rotates around the shaft 24 (rotation center), and the seat 26 moves forward and the rear part of the seat 26 descends. In this case, since the weight of the sitting person is applied to the seat portion 26, when the back frame 20 is tilted, the back frame 20 can be tilted with a force corresponding to the weight of the sitting person.

(Embodiments) Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a side view showing a schematic diagram of the structure of the present invention.

FIG. 2 also shows a plan view.

A support frame 14 is fixed to the upper part of the leg post 12 of the chair.

A bottom plate 15 of this support frame 14 is fixed to the pillar 12, and both side surfaces 14a and 14b stand up from this bottom plate 15. The front ends of the side surfaces 14a, 14b rise gently, and the rear ends are bent upward at an angle of approximately 45 degrees.

A bent portion of an L-shaped link plate 16 is pivotally attached to the tip of the side plates 14a, 14b by a shaft 17. Also, link board 1
The other end of 6 engages with a side surface of a recess 27 on the lower surface of the seat 26 via a shaft 18.

On the other hand, the lateral shape of the back frame 20 is formed into a substantially L-shape, and the horizontal portions (bottom parts) of the back frame 20 are formed by horizontal arms 21a, 21.
The horizontal arms 21a and 21b are arranged along the outside of the side surfaces 14a and 14b of the support frame 14. The middle part of the horizontal arms 21a and 21b is the side plate 1.
4a, 14b are pivotally attached to the rear ends of the horizontal parts via a shaft 24,
This shaft 24 becomes the center of rotation when the back frame 20 tilts.

Additionally, a back plate 19 is fixed to the upright portion of the back frame 20.

Elongated holes 22a and 2 are provided at the tips of the horizontal arms 21a and 21b.
2b is bored, and the long holes 22a, 22b and the link plate 1
The rear ends of the horizontal portions 6 are connected by pins 25. Further, the back frame 20 is rotatably fixed to the rear of the shaft 24 and the side surface of the recess 27 of the seat 26 via a link plate 28 with pins 30 and 32.

As for the pins 30 and 32, the pin 30 is located further back than the pin 32. That is, the link plate 28 is inclined rearward. On the other hand, the link plate 16 is also positioned at an angle substantially equal to the link plate 28.

Further, a shaft 29 is installed at the rear end of the side plates 14a, 14b, and a tension spring 34 is disposed between this shaft 29 and the shaft 18. Then, the back frame 20 is maintained in an upright state with an appropriate force.

This embodiment is constructed as described above. Next, the operation of this embodiment will be explained.

A state in which the user sits on the seat 26 and puts his or her weight on the back frame 20 will be explained.

When the back frame 20 is tilted to position A, the back frame 20 rotates around the shaft 24. Then, the horizontal arms 21a, 21b of the back frame 20
moves upward, and the link plate 16 is rotated about the shaft 17 via the pin 25 that is engaged with the elongated holes 22a and 22b at the tip. In this case, the shaft at the other end of the link plate 16 is B
Rotate to the position.

On the other hand, when the back frame 20 rotates around the shaft 24, the link plate 28 is lowered downward via the pin 32, and the link plate 16 moves the seat 26 forward, so the pin 3o The rear part of the seat 26, which is engaged with the seat 26, is lowered.

When the back frame 20 is tilted in this way, the seat 26 moves forward and the rear part of the seat 26 lowers. In this way, when a person leans on the back plate 19, the back plate 19 and the seat 26 move in conjunction to match the relationship between the person's buttocks and back (see FIG. 3).

Furthermore, when the back frame 20 is tilted, the sink plate 1
The shaft 18 of No. 6 is moved to C, and the seat portion 26 is moved forward. Further, the link plate 28 rotates in the same manner as described above, and the seat portion 26
The rear part of the head is lowered (see Figure 4).

As described above, when the user leans on the back plate 19, the seat 26 moves forward and the rear part of the seat 26 lowers.

Here, the operation of the link board 16 will be described.

When the link plate 16 rotates about the shaft 17 as the back frame 20 tilts, the shaft 18 moves in an arc. That is, axis 1
7 and the axis 18, it moves in an arc so as to pass through the perpendicular line Q passing through the axis 17 in FIG. The position where the perpendicular line 0 is passed is the position where the front part of the seat part 26 is raised the most, and after passing 5, the front end of the seat part 26 moves forward while descending.

Next, the operation of the link board 28 will be described. The pin 32 of the link plate 32 draws a locus of rotation around the shaft 24 as the back frame 20 tilts, while the pin 30 engaged with the seat 26 rotates due to the movement of the link plate 16. It follows the movement of the seat 26 moving forward and descends while moving forward. Therefore, the rear portion of the seat portion 26 descends downward.

As described above, as the back frame 20 tilts, the link plate 1
6 and the link plate 28 transition from the backwardly inclined state to the upright state, the force applied to the back frame 20 is affected by the weight applied to the seat 26.

That is, even if the magnitude of the force applied to the back plate 19 differs depending on the weight of the person sitting on the seat 26, the same tilting operation is performed. In other words, if a person is light in weight, a small force (if the person is
The back plate 19 can be tilted by the weight held on it. On the other hand, if a person is heavy, the weight applied to the seat 26 is large, so the force applied to the back plate 19 is also required to be large (naturally, if a person is heavy, the force applied to the back plate 19 is large). ), that is, by applying a force proportional to the weight of the person sitting on the back plate 19, the back plate 19 is tilted.

Next, other embodiments will be described. The following embodiments differ from the above embodiments in that the horizontal arms 21a, 21b and the seat portion 26 are connected.

In FIG. 5, pins 40 protrude from the butt ends of the horizontal arms 21a, 21b of the back frame 20, and abut against the lower surface 16a of the link plate 16, which is constructed in the same manner as in the above embodiment. Therefore, when the horizontal arms 21a and 21b rotate around the shaft 24, the horizontal arms 21a and 21b rotate.
The tips of 1a and 21b move upward in an arc, the protrusion 4o presses the lower surface 16a of the link plate 16, and the link plate 16 rotates about the shaft 17. Further, the same effects as those of the above embodiment are achieved.

In FIG. 6, one end of an elongated link plate 46 is pivotally attached to the shaft 17, and the other end is pivotally attached to the side surface of the recessed portion of the seat portion 26 via the shaft 18. The link plate 46 is inclined to the rear (to the right in FIG. 6) from the perpendicular line a passing through the shaft 17. Further, horizontal arms 21a and 21b are provided on the lower surface 46a of the link plate 46.
A protrusion 48 protruding from the tip is in contact with the protrusion 48 . For this reason,
When the horizontal arms 21a and 21b rotate around the shaft 32, the protrusion 48 presses the lower surface 46a of the link plate 46, and the link plate 4
6 is rotated around the shaft 17, and the same effect as in the above embodiment is achieved.

In addition, in the embodiment shown in FIGS. 5 and 6 above,
Although the side surface of the link plate 16.46 is pressed by the protrusion 40.48, a long hole may be formed in the link plate 16.46 and the protrusion 40.48 may be engaged with this elongated hole. Many modifications may be made without departing from the spirit of the invention. Of course.

(Effects of the Invention) As described above, by tilting the back plate, the seat moves up and down and forward in conjunction with this movement, so that the weight of the person sitting on the seat Since the movement of the seat is regulated, there is no need to adjust the repulsive force of the tilting of the back plate each time, unlike in the past.

In other words, since the back frame and the seat are pivoted behind the center of rotation of the back frame that supports the back plate, the tilting of the back frame lowers the link plate and rotates it forward. It is possible to realize a positional relationship between the back plate and the seat that corresponds to the positional relationship between the buttocks and the back of a person. Furthermore, the weight of the person sitting is mainly applied to the rear part of the seat, and the repulsive force of the tilting of the back frame changes depending on the size of the person's weight, so the repulsive force of the back frame can be adjusted to suit the physique of the person sitting. It is effective as follows.

[Brief explanation of the drawing]

Figure 1 is a schematic side view showing the tilting structure of the back of the chair;
The figures are also plan views, FIGS. 3 and 4 are explanatory views showing the tilting operation of the back plate, and FIGS. 5 and 6 are explanatory views showing other embodiments. 12... Pillar, 14... Support frame, 19... Back plate, 16.28.46... Link board, 17.18.24... Shaft, 20... Back frame. 26...Seat portion, 25.30.32...Pin, 34...Compression spring, 40.48...Protrusion. Drawing 0 Drawing 46a Procedural amendment August 9, 1988 Patent application No. 112863 2, Title of the invention Chair 3, Relationship with the case of the person making the amendment Patent applicant 7, Subject of the amendment Details Book and Drawing 8, Contents of Amendment 1) The full text of the specification will be amended as shown in the attached sheet. Description 1, Title of the Invention Chair 2, Claim 1, A bottom member of a back frame having a substantially L-shaped lateral shape is disposed below the seat from the rear of the seat toward the front. , the back frame is rotatably supported in the front and back direction on the support part of the support base below the seat at the midway part of the bottom member, and the lower end of the link plate is pivoted on the back frame bottom member behind this support part. The upper end of the link plate is pivoted to the seat so that the link plate faces rearward and tilts upward when the seat is in the standard position, and the back frame rotates rearward about the support. When the link plate is moved, the link plate follows and rotates, and the seat part is rotated to the rear of the back frame until the link plate is tilted forward and upward beyond the standing position where the upper end side of the link plate is upward. The chair is characterized in that the front end side of the bottom member of the back frame and the front end side of the seat part are connected to each other so as to move forward in conjunction with the movement. 3. Detailed Description of the Invention (Field of Industrial Application) The present invention allows the backrest and seat to easily follow the body movements of both heavy and light people. To provide a chair that allows one to easily take a resting position. (Prior Art) When a user sits on a chair for a long period of time, such as an office chair, the user gets tired if he or she takes only one posture, so the user takes various postures. It is desirable that the seat, backrest, etc. move easily according to the movement of the seat. Furthermore, when resting, the user generally leans his or her back against the backrest, and it is desirable to have a chair with a deeper seat and backrest that can easily move to follow the user's movements. As shown in FIG. 6, a conventional chair of this kind is known in which the backrest and seat are supported by a spring lO, and the backrest and seat are tilted backwards when the user leans against the backrest during rest. There is. Further, as shown in FIG. 7, the backrest 19 and the seat part 23 are connected via the hinge joint 13 at the lower end of the backrest 19 and the seat part 23 (at the other end), and the backrest 19 is connected at the upper and lower middle parts thereof. It is pivotally attached to the frame 15 via a horizontal support shaft 14 so as to be rotatable in the front and rear direction, and further includes a seat portion 23.
Both ends of the crossbar 16 fixed to the lower surface are attached to the frame 15.
A chair is known that is movably guided along a long hole 18 of a seat guide 17 provided on the front end side (Japanese Patent Laid-Open No. 61-24
No. 7418). According to this chair, the backrest when resting is 19
When the user leans on the seat, the backrest 19 tilts rearward, and in conjunction with the rearward tilting of the backrest 19, the seat 23 moves forward and upward, allowing a resting position. (Problems to be Solved by the Invention) However, the conventional chair described above has the following problems. In other words, in the chair shown in FIG.
Even in this case, the angle between the backrest and the seat does not change, and the seat does not move forward, so the degree of freedom in taking a working position or a resting position is limited accordingly. Furthermore, when the backrest and seat part tilt, the center of gravity moves rearward, so there is a risk that the user may easily fall backwards. In the chair shown in FIG. 7, when the backrest 19 is tilted backward, the upper side of the backrest 19 tilts backward, but the lower side of the backrest 19 moves forward. Therefore, when the user tries to take a resting posture by leaning the backrest 19 on the backrest 19, there is a problem that the movement of the user's back and the movement of the backrest 19 do not match, resulting in a feeling of discomfort. In addition, since the horizontal support shaft 14 is located midway in the vertical direction of the backrest 19, people who are light in weight or who sit at a low height cannot apply the necessary load to the backrest 19, causing the backrest 19 to tilt backward. There are some problems that make it difficult. Furthermore, since the seat part 23 is connected to the lower end of the backrest 19, although the seat part 23 can move forward, it does not extend to the depth of the seating space, making it difficult to take a comfortable resting position. There is. The present invention has been made to solve the above-mentioned problems, and its purpose is to make it easy for both heavy and light people to follow their body movements when working or taking a resting position. It is an object of the present invention to provide a chair in which a backrest and a seat part can be moved and a comfortable resting position can be taken. That is, the bottom member of the back frame, which has a substantially L-shaped lateral shape, is disposed below the seat from the rear of the seat toward the front, and the back frame is attached to the bottom of the seat at a midway portion of the bottom member. The link plate is supported rotatably in the front and back direction on the support part of the support base on the other side, and the lower end of the link board is pivoted on the back frame bottom member rearward from the support part,
The upper end of the link board is pivoted to the seat so that the link board faces rearward and tilts upward when the seat is in the standard position, and the back frame rotates rearward about the support part. edge,
The seat portion is linked to the rearward rotation of the back frame until the link plate follows and rotates, and the upper end side of the link plate is directed forward and tilted upward beyond the standing position where the upper end side of the link plate is upward. It is characterized in that the front end side of the bottom member of the back frame and the front end side of the seat part are connected in order to move forward. (Operation) Next, the operation of this invention will be described. When a user sits down on the seat while working, the load applied to the seat is distributed around the support portion of the bottom member and canceled out by a balance action. Therefore, when taking various working postures during work, if a slight load is applied to the backrest, the backrest and seat will easily move to follow the movement of the body. The user intentionally applies a load to the backrest by leaning on it.This increases the unbalanced load and causes the backrest to tilt backwards around the support section located below the seat of the bottom member. As the seat moves forward, the seating space expands back and forth,
This allows you to take a relaxed resting position. When trying to tilt the backrest backwards, in the case of a heavy person, the load on the backrest will be greater than in a lighter case, but the load on the support part in the opposite direction from the backrest side is also quite large (, In addition, the resistance force against the backward tilting of the backrest caused by the load from the seat when the link board rotates from the rear to the front side is greater for heavier people, so Both heavy and light people can tilt the backrest backwards by leaning on the backrest to the same degree. (Embodiment) An embodiment of the present invention will be described below in detail based on the accompanying drawings. 1 and 2, reference numeral 20 denotes a pedestal, and a fixed frame 21 serving as a support base is fixed to the upper end.Fixed frame 2
1, the front end side rises gently toward the front, and the rear end side rises rearward at a relatively steep angle. It goes without saying that the present invention can also be suitably applied to chairs without pillars. Reference numeral 12 denotes a back frame, which has a substantially L-shaped lateral shape and is composed of a bottom member 22 and a back support rod 26 provided at the rear end of the bottom member. A back plate 25 is attached to the front surface of the back support rod 26. The backrest 19 is composed of the back support rod 26, the back plate 25, etc. The bottom member 22 has a seat portion 23 along both sides of the fixed frame 21.
It extends below and in the front-rear direction of the seat portion 23, and is rotatably pivoted to the fixed frame 21 at a midway portion thereof. 24 is its rotation axis (supporting part). Reference numeral 27 denotes an L-shaped link, which is rotatably attached to a shaft 28 at an L-shaped bent portion on both sides of the front end side of the fixed frame 21. One end of the L-shaped link 27 is attached to the front side of the seat 23 by a shaft 29, and the other end of the L-shaped link 27 is attached to the front end of the bottom member 22. They are connected by a pin 30 and a long hole 31. That is, a pin 30 protruding from one end of the L-shaped link 27 is loosely fitted into an elongated hole 31 provided at the front end of the bottom member 22 and extending in the front-rear direction. It goes without saying that the pin may be provided on the bottom member 22 and the elongated hole may be provided on the L-shaped link 27 side. The rear side of the seat portion 23 is connected to the rotation shaft 24 by a link plate 32.
It is supported on the bottom member 22 on the rear side. That is, one end of the link plate 32 is pivotally attached to the rear part of the seat part 23 by the shaft 33, and the other end is attached to the bottom member 2 on the rear side of the rotation shaft 24.
2 by a shaft 34. Reference numeral 35 denotes a tension spring for return and balance, which is hooked between the shaft 29 of the above-mentioned cross-shaped link 27 and a fixed shaft 36 provided at the rear end of the fixed frame 21, so that the seat 23 can be used as a chair. while biasing the L-shaped link 27 to its original standard position.
The backrest 19 is biased through the bottom member 22 to its original standard position (upright position). Note that when the seat portion 23 and the backrest 19 are urged to the standard position by the tension spring 35 and are stationary as described above, the line connecting the shafts 28 and 29 of the L-shaped link 27 and the link plate 32 As is clear from FIG. 1, the line connecting the shafts 34 and 33 is set to slope rearward and upward. Further, at this time, a line connecting the shaft 28 of the L-shaped link 27 and the pin 30 is inclined rearward and downward. Next, its operation will be explained. First, when you sit down on the seat 23 in the standard position shown in FIG.
Force is distributed to the points of application before and after. The load due to this component imparts a clockwise moment to the bottom member 22 through the link plate 32 about its rotation axis 24, and a counterclockwise moment through the L-shaped link 27. Give a moment. Note that when the counterclockwise moment is larger, the bottom member 22 rotates counterclockwise about the rotation axis 24, but a stopper (not shown) acts, and the seat part 23 and the backrest 19 are returned to the standard position. It is located in Also, when the clockwise moment is larger, the bottom member 2
2 tries to rotate clockwise, but the tension spring 3
5, the standard state is maintained when no load is applied to the backrest. In this case (also when taking a resting position as described later), in this embodiment, the load is distributed around the support portion of the bottom member 22, and the balance is offset by the balance action. , the clockwise moment corresponding to the unbalance is relatively small. Therefore, the tension spring 35 described above does not need to be a very strong spring. The fact that the strength of the tension spring 35 does not have to be so great has the following advantages. In other words, even when working, the worker may take a posture of leaning slightly on the backrest 19, but in this case, the strength of the tension spring 35 is not very strong, so the backrest 19 is tilted slightly backwards. This allows the user to take a comfortable working posture (in this case, the seat 23 moves slightly forward). In this way, even when working, the seat 23 and backrest 19
can be easily moved to follow the movements of the body. This can be done with little difference between heavy and light weight people. In other words, for both heavy and light people, the balance of the load around the support part is offset by the balancing action of the bottom member 22, so even a light person can resist the tensile force of the tension spring 35, which is not very strong. This allows the backrest 19 to be easily tilted. Next, when transitioning to a resting state, the user intentionally leans on the backrest 19 and applies a load to the backrest 19, resisting the tensile force of the tension spring 35 and the resistance force due to the load described later. It is tilted rearward about the rotation axis 24. In this case as well, both heavy and light people can tilt the backrest 19 backwards with little difference. That is, in the case of a person with a heavy weight, a larger load is applied to the backrest 19, and in the case of a person with a lighter weight, a larger load is applied to the backrest 19.
Although a relatively small load will be applied to the support portion of the bottom member 22, in the case of a heavy person, the load acting in the opposite direction to the load applied to the backrest 19 will be applied to the supporting portion of the bottom member 22. This occurs a lot more than in humans, and is offset by the balance action, so both heavy and light people can tilt the backrest 19 backwards with almost the same degree of leaning. When the backrest 19 is tilted backward, the front end side of the bottom member 22 rotates upward in an arc around the rotation shaft 24, thereby causing the L-shaped link 27 to move to the left in FIG. 1 around the shaft 28. Rotate. That is, the shaft 28 of the L-shaped link 27
The link piece connecting the shaft 29 to the shaft 29 gradually rises from the rearward tilted position shown by the solid line in FIG. 1, and rotates beyond the raised position to a slightly forwardly tilted position. Therefore, the seat portion 23 moves forward as the L-shaped link 27 rotates. Further, at this time, the front side of the seat portion 23 rises slightly as shown by the broken line in FIG. On the other hand, as the seat portion 23 moves forward, the link plate 32 also moves the shaft 34 from the backward inclined position shown by the solid line in FIG. Rotates around the center. By the way, the shaft 34 rotates in an arc around the rotation shaft 24 as the bottom member 22 rotates, and is slightly lowered from the standard position. Therefore, the rear side of the seat portion 23 moves forward and sinks slightly in conjunction with the rearward tilting of the backrest 19. In this way, the seat 23 moves forward in conjunction with the rearward tilting of the backrest 19, but at this time, the front side of the seat 23 rises slightly and the rear side of the seat 23 sinks slightly. I will do it. By the way, when the link piece of the L-shaped link 27 and the link plate 32 rotate from the backwardly inclined state to the upright position as described above, the load from the user is applied to the link piece and the link plate 32. acts as a kind of resistance force against backward tilting of the backrest 19. The resistance force due to the load at this time prevents the backrest 19 from falling all at once backwards when a load is applied to the backrest 19. In particular, as mentioned above, since the tensile force of the tension spring 35 is small, if a large load is applied to the backrest 19, there is a risk that the backrest 19 will fall backwards all at once. This acts to effectively prevent the backrest 19 from tilting rearward all at once. Next, as the backrest 19 tilts, the load on the backrest 19 gradually increases (becomes), while as the aforementioned link pieces and link plates 32 stand up, the previously increased resistance force decreases (' Therefore, The above-mentioned resistance force and 5' of the tension spring 35
The tensile force and the gradually increasing load applied to the backrest 19 are balanced at a certain position. The above tension spring 35
also acts as a balancer in this case. Of course, the user's muscular strength such as abdominal muscle strength also acts, and the backrest 19 stops tilting backwards at a position where these forces are balanced, and a resting posture can be taken at this stopped position. When taking this resting position, the backrest 19 tilts rearward about the pivot shaft 24 located below the seat 23, as described above, and the seat 23 moves forward, so the pressure space moves back and forth. This allows you to spread out and take a relaxing resting position. Furthermore, when the seat 23 moves forward, the rear side of the seat 23 moves forward but sinks slightly, as described above.
Movement of the buttocks when trying to take a resting position and the seat 23
The movement almost coincides with that of the rest position, and it is possible to shift to an unnatural (resting position).Although not shown, it is of course possible to provide a locking device to prevent the backrest 19 from tilting further backwards in this resting position.Standard In order to return to the original state, it is obvious that if the user straightens his or her back or stands up from the chair, the seat portion 23 and the backrest 19 will return to their standard positions due to the tensile force of the tension spring 35. Fig. 5 shows another embodiment. The same members as in the above embodiment are given the same reference numerals. In this embodiment, the L-shaped link 27 and the bottom member 22
The front end is not connected by a pin and a long hole (but is connected by a cam, that is, the pin 40 provided at the front end of the bottom member 22 is brought into contact with the lower surface of the L-shaped end of the L-shaped link 27. As a result, When the bottom member 22 rotates around the rotation shaft 24, the pin 40 rotates the L-shaped link 27 around the shaft 28, so that almost the same effect as in the embodiment described above is achieved. Although the front end of the bottom member 22 and the front end of the seat portion 23 are connected by the L-shaped link 27, the L-shaped link 27 is not limited to this. The resistance force from the link plate 32 and the L-shaped link 27 during exercise is such that when a load is applied to the backrest 19, the load on the seat 23 moves from the front side to the rear side. This is because even if there is no L-shaped link 27 on the front side, if there is a link plate 32 on the rear side of the seat portion 23, the above-mentioned necessary resistance force can be sufficiently generated from the link plate 32. Although various embodiments have been described, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. ( Effects of the Invention) As described above, according to the chair according to the present invention, the load on the seat part is offset by the surface of the support part of the bottom member, and when working,
The seat and backrest can be easily moved to follow the movements of the body when taking various working postures, and you won't get tired even if you sit for long periods of time. Since a corresponding resistance force is generated, both heavy and light people can tilt the backrest backwards with almost the same amount of leaning on the backrest, and the backrest can be rotated so that it is located below the seat. Since it tilts backwards around its axis, while the seat moves forward, the pressure space expands back and forth, making it possible to take a relaxed resting position. 4. Brief description of the drawings FIG. 1 is a schematic side view showing the connection between the balance member and the seat, and FIG. 2 is a plan view thereof. FIG. 3 is a side view of the L-shaped link with the link piece and link plate in the upright state, and FIG. 4 is a side view of the L-shaped link in a state where it is tilted forward beyond the upright state. FIG. 5 is an explanatory diagram showing another embodiment, and FIG. 6 is an explanatory diagram showing another embodiment.
FIG. 7 and FIG. 7 are explanatory diagrams each showing an example of a conventional chair. 1゛ 12... Back frame, 19... Backrest, "2
0... Pillar, 21... Fixed frame, 22... Bottom member, 23... Seat, 24... Rotating shaft, 25...
・Back plate, 26... Back support rod, 27... L-shaped link, 28... Shaft, 29... Shaft, 30... Bin, 31... Long hole, 32...・Link board, 33...
・Shaft, 34... Shaft, 35... Tension spring, 40
···pin. Front view 1
9th 2nd drawing drawing drawing! @Figure 5 Drawing No. 6 Drawing Q

Claims (1)

[Claims] 1. The bottom part of the back frame, which supports the back board and has an approximately L-shaped lateral shape, extends below the seat, and the middle part of this bottom part is attached to a support frame fixed to the top end of the pillar. One end of the link plate is pivoted on the back frame rearward from the center of rotation, and the other end of the link plate is pivoted on the seat so that the link plate is tilted backward. The chair is characterized in that the tip of the bottom part of the back frame is connected to the seat so that the seat moves forward when the back frame rotates rearward about the center of rotation. .