JPH0245012A - Chair with seat back - Google Patents

Abstract

PURPOSE:To obtain a satisfactory appearance and the satisfactory fitting sense of a user and to follow the various positions of the user when the user takes a rest by enlarging the seat space between a seat back part and a seat part by moving the seat part forward while tilting the seat back part backward with the internal mechanism of the title chair when the user leans against the seat back part and applies a load to the seat back part. CONSTITUTION:When the user of the chair is under a standard position state, the load is separated through a seat part base 73 to the front and rear application point parts of a supporting point part 74 of a balancing member 72, and since the balanced amount is offset by a balancing function, a spring which is not so strong is enough for an extension spring 85. When the user of the chair is under a resting state, although the user leans against the seat back part and tilts a back supporting rod 76 backward around a turning shaft 74, the back supporting rod 76 is tilted backward with the approximately same leaned condition for both a heavy person and a light person also by the balancing function, the tip side of the balancing member 72 circularly rotates upward around the turning shaft 74 by the tilting of the back supporting rod 76, an L-shaped link 77 is gradually risen, and the seat part base 73 is moved forward.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a chair with a backrest, and more specifically, a chair in which the seat part moves forward while the backrest part tilts backward,
To provide a chair with a backrest in which the upper side of the backrest part can be tilted rearward with respect to the lower part side at any position of the backrest part, and a user can take various resting postures.

(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 in response to the movement of the seat. Furthermore, when taking a break, the user generally leans his or her back against the backrest, and it is desirable to have a chair in which the seat and backrest can move more deeply to follow the user's movements.

Furthermore, there is a need for a chair that allows the seat and backrest to return to their original, standard positions when not in use.

Conventional chairs of this kind are known in which, for example, a backrest and a seat are supported by a spring or the like, and the backrest and the seat tilt backward when the user leans on the backrest during rest.

In addition, the backrest part and the seat part are connected via a hinge joint at the lower end of the backrest part and the rear end of the seat part, and the backrest part can be rotated in the front and back direction by a horizontal support shaft at the midway point in the vertical direction. A chair is known in which both ends of a crossbar that is freely pivoted to a frame and fixed to the lower surface of the seat are movably guided along long holes in the seat guide provided at the front end of the frame ( Japanese Patent Publication No. 61-247418
Publication No.).

According to this chair, when you lean on the backrest while resting, the backrest tilts backwards, and in conjunction with the backward tilting of the backrest, the seat moves forward and upward, thereby improving your resting posture. It is now possible to take it.

However, the conventional chair described above has the following problems.

In other words, in the former type of chair, the backrest and seat tilt backwards in response to the user's movements, but the angle between the backrest and seat does not change even at that time. Since the seat does not move forward, the degree of freedom in taking a working position or a resting position is limited accordingly.

Furthermore, when the backrest and the seat tilt, the center of gravity moves rearward, so there is a risk that the user may easily fall backwards.

Furthermore, in the above chair, the load applied to the backrest varies depending on the user's weight, so it is essential to make an initial adjustment to adjust the strength of the springs before use according to the user's weight. It is not always easy for the user to make this initial adjustment optimally, and since the strength of the spring is set according to the user's weight, it is generally recommended that the chair be used only as a chair exclusively for that user. Therefore, it is not suitable as a chair for a meeting room, which is used by an unspecified number of people.

In the latter chair, when the backrest is tilted backward, the upper part of the backrest tilts backward, but the lower part of the backrest moves forward. Therefore, when the user tries to take a resting position by leaning the backrest against the backrest, the user's back movements do not match the movements of the backrest, creating a sense of discomfort.

In addition, since the horizontal support shaft is located midway in the vertical direction of the backrest, people who are light in weight or have a low sitting height cannot apply the necessary load to the backrest, causing the backrest to tilt backwards. There are certain sight points where it is difficult to

Furthermore, since the seat is connected to the lower end of the backrest, although the seat can move forward, it does not extend to the depth between the seats, making it difficult to take a comfortable resting position. There is.

(Background Art) Therefore, the inventors of the present invention previously proposed a chair that improves the drawbacks of the conventional chair with a backrest.
Specification No. 392, Specification of Japanese Patent Application No. 193393/1986,
Patent Application No. 193394, 1983, and Patent Application No. 1986-
This was proposed in the specification of No. 193395.

Such a chair is a chair with a backrest, and includes a seat base;
a support base; a balance member supported by the support base below the seat base in the front-rear direction of the seat base; and a balance member provided with a back support rod at the rear; and a balance member that moves the seat base in the front-rear direction. The back support rod includes a seat support part that freely supports the seat base and divides the load on the seat base to an application point part that pinches the fulcrum part of the balance member, and the back support rod is arranged rearwardly about the fulcrum part of the balance member. force transmission means for converting the backward tilting motion of the balance member when tilting into the forward motion of the seat base through the seat support; The chair is equipped with a mechanical elastic body that returns the support rod to the chair's original resting position.

This chair is a chair in which the backrest tilts backward and the seat moves forward, and the backrest and seat can be easily moved to follow the movement of the body, making it easy to take a resting position. It is something.

In order to improve the appearance of such a chair and to make the backrest fit the user's back, the structural members constituting the internal mechanism, such as the balance member, seat base, and back support rod, are combined into a shell structure. It would be advantageous if it could be substantially encapsulated.

However, in this type of chair, in which the seat moves forward as the backrest tilts backward, that is, the seat between the seat and the backrest opens wide, the shell structure substantially covers the structural member. It is difficult to package.

(Purpose of the Invention) As a result of various studies to solve the above problems, the inventors of the present invention came up with the idea that the problem can be solved by assembling the two shell members that make up the shell structure so that mutual misalignment is allowed. did.

That is, an object of the present invention is to provide a chair in which the backrest portion and the seat portion are movable, but the structural members such as the seat base, the back support rod, and the balance member can be substantially covered by the shell member.
In addition to improving the appearance and fit, the upper part of the shell structure, that is, the upper part of the backrest, can be bent backwards relative to the lower part of the chair, allowing for a deeper resting posture. It is on offer.

(Means for solving problems) The above object is achieved by the following configuration.

That is, in a chair with a backrest, the chair has the following [I
This is a chair with a backrest, characterized by having an internal mechanism that satisfies the following (If) and a structure of the backrest that satisfies the following (If).

[I] Internal mechanism (i) Seat base; (ii) Support base; (iii) Below the seat base, supported by the support base in the front-rear direction of the seat base, and at the rear. a balance member provided with a support rod; (iv) supporting the seat base so as to be movable in the front-back direction, and distributing the load on the seat base to application point parts that sandwich the fulcrum part of the balance member; When the back support rod tilts rearward about the fulcrum part of the balance member, the backward tilting movement of the balance member is controlled by the seat support part, and the forward movement of the seat base is controlled by the seat support part. and (v) a mechanical elastic body that returns the seat base and the backrest to the original rest position of the chair via the nuclear force transmission means.

(n) Structure of the backrest The backrest including the back support rod of the internal mechanism (1) is integrally assembled with a plurality of locking devices around which two elastic shell members are arranged. Among the locking devices of the shell structure corresponding to the backrest portion, the locking devices of the shell structure (in both the upper and lower middle portions) prevent the shell structure from tilting backward. The structure allows for the misalignment that occurs between the two shell members when
When a user leans on the backrest, the upper side of the backrest can elastically tilt rearward relative to the lower side in response to the load.

In such a chair with a backrest, the locking tool at least in the vertical middle of the shell structure allows the L-shaped body protruding from one shell member to loosely insert into the through hole provided in the other shell member. In addition, the hole edge of the other shell member may be inserted into the claw portion of the ML-shaped body, and/or the shell structure corresponding to the backrest may have a backrest extending halfway in the vertical direction. The fact that the shell structure includes the support rod and is tiltable backwards using the vicinity of the upper end of the back support rod as a fulcrum makes it easier to move the upper side of the backrest relative to the lower side. .

In addition, the "internal mechanism" as referred to in the present invention is sufficient as long as the structural members constituting the mechanism are substantially covered by the shell structure, and a part of the structural member, for example, the back support rod, is covered by the shell structure. It may be provided outside.

(Function) In the chair with a backrest of the present invention, when a user leans on the backrest and applies a load to the backrest, the internal mechanism of the chair causes the backrest to tilt backward and the seat to move forward. The space between the seat and the seat can be expanded, allowing you to take a resting position.

At this time, the shell structure creates a necessary misalignment between the two shell members, and moves to follow the movements of the backrest and seat while maintaining the shell structure.

Further, when the user tries to take a more comfortable posture by leaning the upper part of the back on the upper part of the backrest part, the shell structure tilts backward using the upper end of the back support rod as a fulcrum while still maintaining the shell structure.

At this time, the upper back is supported by an appropriate reaction force from the shell structure according to the load applied by the user, allowing the user to take a deeply comfortable posture.

In this way, the backrest can be tilted backwards at any angle, and the seat can be moved forward in conjunction with the backward tilting of the backrest. The upper side of the backrest can also be tilted rearward with respect to the lower side, allowing the user to take various resting positions.

Also, since the backrest portion is substantially covered by the shell structure, the fit is increased.

Furthermore, when the user raises his or her back from the backrest or stands up from the chair, the upper side of the backrest returns to its original state due to the elasticity of the shell structure and shell members, while the backrest and seat remain in the internal mechanism. The chair returns to its original standard position by the biasing force of the mechanical elastic body.

(Example) An embodiment of the present invention will be described in more detail with reference to the drawings.

FIGS. 1 and 2 show an embodiment in which the present invention is applied to a chair having legs.

In the figure, 1 is a backrest portion, 2 is a seat portion, 3.4 is a shell member constituting the shell structure of the chair, and 5 is a cushion portion.

As shown in FIGS. 1 and 2, the chair of this embodiment includes a shell member 4 (hereinafter sometimes referred to as an inner shell) in contact with a cushion part 5 and a shell member 3 (hereinafter referred to as an inner shell) forming the rear part of the backrest part 1. It has a shell structure made up of an outer shell (sometimes referred to as an outer shell) and an internal mechanism shown in FIG.

In this internal mechanism, a fixed frame 71 serving as a support base is fixed to the upper end of the footnote 70. The front end of the fixed frame 71 rises gently toward the front, and the rear end rises rearward at a relatively steep angle.

Reference numeral 72 denotes a balance member, which extends along both ends of the fixed frame 71, below the seat base 73, and in the front-rear direction of the seat base 73. It is worn. 74 is its rotation axis (fulcrum part).

76 is a back support frame provided at the rear end of the balance member 72.

Reference numeral 77 denotes an L-shaped link, which is rotatably attached to both sides of the front end of the fixed frame 71 by a shaft 78 at an L-shaped bent portion. One link end of the L-shaped link 77 is pivoted to the front side of the seat base 73 by a shaft 79, and the other link end of the L-shaped link 77 is attached to the front end of the balance member 72. are connected to each other by a pin 80 and a long hole 81. That is, a pin 80 protruding from one end of the L-shaped link 77 is loosely fitted into an elongated hole 81 provided at the front end of the balance member 72 in the front-rear direction.

It goes without saying that the pin may be provided on the balance member 72 and the elongated hole may be provided on the L-shaped link 77 side.

The rear side of the seat base 73 is supported by a link plate 82 on the balance member 72 on the rear side of the rotation shaft 74. That is, the link plate 82 has one end connected to the seat portion 73 by the shaft 83.
The other end is pivotally attached to the rear part of the balance member 72 by a rotation shaft 74 and the other end is pivoted to the rear balance member 72 by a shaft 84.

The L-shaped link 77 and the link plate 82 constitute a seat support portion. Furthermore, by connecting the L-shaped link 77 to the tip of the balance member 72 through the pin 80 and the elongated hole 81,
It constitutes a force transmission means for moving the seat base 73 forward.

Reference numeral 85 designates a tension spring for return and balance, which is hooked between the shaft 79 of the cross-shaped link 77 and a fixed shaft 86 provided on the rear end side of the fixed frame 71, and is used to use the seat 73 as a chair. while biasing the L-shaped link 77 to its original standard position.
The back support rod 76 is urged to the original standard position (erected position) of the chair via the balance member 72.

In addition, as mentioned above, the seat base is fixed by the tension spring 85! 73 and the back support rod 76 are biased to the standard position and at rest, a line connecting the shafts 78 and 79 of the L-shaped link 77 and a line connecting the shafts 84 and 83 of the link plate 82 are It is set to slope upward and towards the rear. Further, at this time, a line connecting the shaft 78 of the L-shaped link 77 and the pin 80 is inclined rearward and downward.

On the other hand, the shell structure is such that the outer shell 3 and the inner shell 4 are assembled together by locking devices arranged along the outer periphery of the outer shell 3 and the inner shell 4 to substantially enclose the internal mechanism. .

That is, the shell structure has a corresponding inner shell 4
The back support rod 76 is fixed to the upper surface of the seat base 73 with screws or the like on the lower surface thereof, and extends halfway into the space of the shell structure on the backrest side.

On the other hand, a portion of the outer shell 3 corresponding to the seat base 73 is cut out.

As shown in FIG. 1, in the chair of this embodiment, when a person leans on the backrest 1, the backrest 1 tilts backward and the seat 2 moves forward, and the upper side of the backrest 1 moves toward the lower side. It can be tilted backwards.

That is, the shell structures corresponding to the backrest portion and the seat portion can follow the movement of the internal mechanism, and the upper part of the shell structure corresponding to the backrest portion can elastically move backward around the upper part of the back support rod 76. It is designed to be able to bend.

In other words, when the shell structure deforms, the degree of deformation of the inner shell 4 and the outer shell 3 is different, so that among the locking tools, the locking tool located from the middle to the bottom of the backrest portion in the vertical direction The structure allows for misalignment between both shell members, so that the shell structure can easily follow the movement of the internal mechanism, and the shell structure can be smoothly bent to correspond to the backrest.

Next, the structures of the inner shell 4 and outer shell 3 will be explained in more detail.

The inner shell 4 and the outer shell 3 are each integrally molded into a predetermined shape from, for example, an elastic synthetic resin material, polypropylene, polyethylene, polyvinyl chloride, polyamide, polyester, or the like.

As is clear from FIG. 2, the inner shell 4 is formed so that its lateral shape is oval-shaped, and a fitting edge 6 protruding toward the outer shell 3 is formed on its outer periphery.

The outer shell 3 is shaped to fit into the inner shell 4 from the rear, and a predetermined space is formed near the center with respect to the inner shell 4 as shown in the figure, but the outer shell 3 is shaped to fit into the inner shell 4 from the rear. It is shaped to fit within the edge 6. For this reason, the outer shell 3 is curved toward the inner shell 4 near its outer periphery.

Note that the outer peripheral portion of the inner shell 4 may be curved.

Further, in the shell structure portion above the upper end of the back support rod 76, the space between the inner shell 4 and the outer shell 3 is set small, making it easy for this portion to bend rearward.

In such a shell structure, the seat base of the internal mechanism! ? 3
The outer shell 3 and the inner shell 4, which cover the outer shell, are fixed at their outer peripheries with screws 87, etc., while both shells on the backrest side are fixed with a locking tool 20 shown in FIG.
．． 30, . . . , 60 are integrally assembled to allow for misalignment.

3 and 4 show the structure of the locking devices 20, 30, . . . , 60.

The locking tool 50.60 is formed in an L-shaped body 12 that protrudes in an L-shape on the surface of the outer shell 3 facing the inner shell 4, and the protruding direction of the claw portion of this L-shaped body 12 is It faces toward the upper side of the backrest portion l. The L-shaped body 12 protrudes onto the outer surface of the inner shell 4 by loosely inserting the through hole 15 provided in the corresponding inner shell 3 portion, and the peripheral edge of the through hole of the inner shell 4 is inserted inside the claw portion of the L-shaped body 12. is involved.

It will be understood that this allows the inner shell 4 and the outer shell 3 to be assembled together, and also allows for displacement of both shells when the upper part of the shell structure is bent backward.

Incidentally, this deviation will be further described later.

The locking tools 20 and 30 that lock the upper parts of the inner shell 4 and the outer shell 3 are also formed in the same L-shaped body 11, but the protruding direction of the claw portion of this L-shaped body is L-shaped. body 1
The protruding direction of the claw portion of No. 2 is opposite to the direction of protrusion. Therefore, as can be seen from FIG. 4(a), the upper edge of the outer shell 3 engages within the fitting edge 6 of the inner shell 4, and
Since the peripheral edge of the through hole 10 provided in the inner shell 4 is inserted into the downwardly facing claw portion of the L-shaped body 1, the upper part of the inner shell 4 and the outer shell 3 is connected to the L-shaped body 11.
Due to the action of the fitting edge 10 and the fitting edge 10, it is substantially in a fixed state.

The locking tool 40 is also formed into an L-shaped body, and the protruding direction of the claw portion thereof is directed toward the center line of the shell structure.

Next, the operation will be explained.

First, to explain the internal mechanism of this embodiment, when you sit down on the chair in the standard position shown in FIG. Force is distributed to the points of application before and after. The load due to this component force applies a clockwise moment to the balance member 72 around its rotation axis 74 via the link slope 82 on the one hand, and a counterclockwise moment via the L-shaped link 77 on the other hand. Grant.

In addition, when the counterclockwise moment is larger, the balance member 7
2 rotates counterclockwise around a rotation axis 74, with the action of a stopper (not shown), so that the seat base 73 and the back support rod 76 are located at the standard position.

Further, when the clockwise moment is larger, the balance member 72 tries to rotate clockwise, but the tension spring 8
5 acts, the standard state is still maintained when no load is applied to the back support rod 76.

In this case (also when taking a resting position as described later), the load is distributed around the fulcrum of the balance member 72, and the balance is canceled out by the balance, so the unbalance is The above clockwise moment is relatively small.

Therefore, the tension spring 85 described above does not need to be a very strong spring.

The fact that the strength of the tension spring 85 does not have to be so great has the following advantages.

That is, even when working, the worker may take a posture of leaning slightly on the backrest, but in that case, the strength of the tension spring 85 is not very strong, so the back support rod 76 tilts backward. .

In this case, the seat base 73 moves slightly forward, and the seat also moves forward.

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 fulcrum is offset by the balancing action of the balance member 72, so even a light person can absorb the tensile force of the tension spring 85, which is not very strong. This allows the back support rod 76 to be easily tilted.

Next, when transitioning to a resting state, the user intentionally leans on the backrest part and applies a load to the back support rod 76, resisting the tensile force of the tension spring 85 and the resistance force due to the load described later. The support rod 76 is tilted rearward about the pivot shaft 74.

In this case as well, both heavy and light people can tilt the back support rod 76 backwards with almost no difference.

That is, in the case of a heavy person, a large load will be applied to the back support rod 76, and in the case of a light person, a relatively small load will be applied to the back support rod 76, but the balance member 72
The load acting in the opposite direction to the load applied to the back support rod 76 is greater in the case of a heavier person than in a lighter person, and is canceled out by the balance action. Therefore, both heavy and light people can tilt the back support rod 76 rearward with approximately the same amount of leaning.

When the back support rod 76 is tilted backward, the tip side of the balance member 72 rotates upward in an arc around the rotation axis 74, and as a result, the L-shaped link 77 rotates around the axis 74 as shown in FIG. Rotate to the left. That is, the link piece connecting the shafts 78 and 79 of the L-shaped link 77 gradually stands up from the rearward inclined position shown in FIG. 2, and rotates beyond the standing position to a position slightly inclined forward. Therefore, the seat base 73 moves forward as the L-shaped link 77 rotates. Further, at this time, the front side of the seat base 73 rises slightly.

On the other hand, as the seat base 73 moves forward, the link plate 82 also rotates about the shaft 84 from the rearward tilted position to the slightly tilted forward position beyond the upright position. By the way, the shaft 84 rotates in an arc around the rotation shaft 74 due to the rotation of the balance member 72, and is slightly lowered from the standard position.

Therefore, the rear side of the seat base 73 moves forward and sinks slightly in conjunction with the rearward tilting of the back support rod 76.

In this way, the seat base 73 moves forward in conjunction with the rearward tilting of the back support rod 76, but at this time, the front side of the seat base 73 rises slightly, and the rear side of the seat base 73 moves forward. will move slightly downward.

By the way, when the link piece of the L-shaped link 77 and the link plate 82 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 82. acts as a kind of resistance force against the rearward tilting of the dorsal rod 76. The resistance force due to the load at this time prevents the back support rod 76 from falling all at once backwards when a load is applied to the back support rod 76.

In particular, as mentioned above, the strength of the tension spring 85 is not so great, and its tensile force is particularly small at the initial stage of extension, so the resistance force prevents the back support rod 76 from tilting all at once. It works effectively to

Next, as the back support rod 76 tilts, the load on the back support rod 76 gradually increases, while as the aforementioned link piece, link Fi82, stands up, the aforementioned resistance force decreases.

Therefore, the above-mentioned resistance force and the tensile force of the tension spring 85 and the above-mentioned gradually increasing load applied to the back support rod 76 are balanced at a certain position. The tension spring 85 described above also acts as a balancer at that time. Of course, the user's muscular strength such as abdominal muscle strength also acts, and the backward tilting of the dorsal rod 76 stops at a position where these forces are balanced, and a resting posture can be taken at this stopped position. When taking this resting posture, the back support rod 76 is positioned below the seat base 73 as described above on the rotation shaft 7.
4, and the pressure part base 73 moves forward, so that the middle of the seat spreads forward and backward, allowing a comfortable resting posture.

Moto Zabe again! When the seat base 73 moves forward, as described above, the rear side of the seat base 73 moves forward but sinks slightly, so the movement of the buttocks when trying to take a resting position and the movement of the seat base 73 are almost the same. This allows you to shift to a resting position without feeling any discomfort.

Although not shown, it is of course possible to provide a locking device for preventing further rearward tilting of the back support rod 76 at this rest position.

To return to the standard state, the seat base 73 and the back support rod 76 are returned to their standard positions by the tensile force of the tension spring 85 when the user straightens his or her back or stands up from the chair.

Such movement of the seat base 73 and the back support rod 76 is caused by the fact that the shell structure is assembled to allow displacement with respect to the inner shell 4 connected to the seat base 73 and the inner shell 4. This is done smoothly because the outer shell 3 is made up of two outer shells.

In addition to the shell structure being able to follow the movement of the internal mechanism as described above, the chair of this embodiment also allows the upper part of the backrest to further tilt relative to the lower part, allowing it to assume various postures.

In other words, when the user tries to take a more comfortable posture by leaning the upper part of the back on the upper part of the backrest part l, the shell structure body resists the rigidity of the shell structure and the back support rod 7
6. It is bent backwards using the upper end as a fulcrum.

The shell structure employed in this embodiment can follow the movement of the internal structure, and the movement in which the upper side of the shell structure corresponding to the backrest portion is bent backwards with respect to the lower side is a combination of the inner shell 4 and the outer shell. This is possible because the locking tool allows for misalignment between the two shells even though the two shells are assembled together.

While the back support rod 76 of the internal mechanism tilts backward, the seat base 73
When the backrest 1 moves forward, or when the upper part of the backrest part 1 is bent backward relative to the lower part, the load is applied to the outer shell 3 in its compression direction, and to the inner shell 4 in its extension direction. act. Since the inner shell 4 and the outer shell 3 are fixed at the upper and lower portions as described above, the compressive force on the outer shell 3 acts in a direction that causes the curved portion A of the outer shell 3 to further curve outward slightly. That will be understood.

Therefore, this makes it possible to bend the inner shell 4 and the outer shell 3. This inner shell 4
As is clear from FIG. 2, when the backrest tilts backward and the seat moves forward, the inner shell 4 deforms in the directions of arrows G and I in the figure. The outer shell 3 is compressed and expanded in the directions of arrows H, and when the upper side of the shell structure corresponding to the backrest is bent backward relative to the lower side, the seat base 73 does not move forward. Inner shell 4 is expanded and compressed in the direction of arrow G in the figure, and outer shell 3 is expanded and compressed in the direction of arrow H, respectively.

As a result, a shift occurs between the two shells, and this shift is allowed by the locking devices 20, 30, . It can be tilted smoothly backwards, or the upper side of the shell structure can be smoothly bent relative to the lower side.

What should be noted here is that the inner shell 4 and the outer shell 3 deform while maintaining their shell structure. That is, both shells are fixed at their upper and lower parts, and even if a shift occurs in the middle, both shells are retained by the locking tools 20, 30, . . . , 60 and the shift occurs. It is.

In this way, both shell structures are deformed while being held, so when bending the upper side of the shell structure corresponding to the backrest backwards with respect to the lower side, the user can take advantage of the moderate reaction force of the shell structure. The upper side of the backrest can be tilted rearward with respect to the lower side while receiving the external force, and when the external force is removed, the backrest can easily return to its original position.

Although the upper portions of both shells that undergo such deformation are substantially fixed as described above by the structure of the L-shaped body 11 and the fitting edge 6, there is actually some displacement. The locking device 20.30 is configured to allow this slight deviation. The upper parts of both shells may be completely fixed with screws, etc., but when the shell structure tries to tilt or bend backwards, large forces of expansion and compression are applied to the upper parts of both shells, causing a large displacement effect. Because of this, there is a problem in durability when fixing with screws, and it is rather preferable to have a structure that allows slight deviation as described above.

The L-shaped body 12 of the locking tool 50.60 is shown in FIG. 4(b).
, (c), by providing ribs 13 on a portion of the slope and reinforcing it, the thickness of the slope forming the L-shaped lower body 12 can be made as thin as possible.

Alternatively, a locking device shown in FIG. 5 can be used as a locking device in place of the locking devices shown in FIGS. 3(b) and 3(C).

As shown in FIG. 5(i), the locking tool shown in FIG. A claw-like body 91 is formed on the outer shell 3.

The claw-like body 91 has a wedge-shaped cross section and a long side shorter than a long side of the opening 92 .

When such a claw-like body 91 is pushed into the opening 92, the fifth
As shown in Figure (ii), the shells can be moved in the direction of the arrow, so it is possible to tolerate the displacement between the shells caused by tilting the upper side of the backrest portion backward with respect to the lower side.

By forming one long side of the opening 92 into a claw-like shape 90, as shown in FIG. 5, the claw-like body 91 can be easily pushed in. After entering the closet,
The claw-like bodies 91 are prevented from coming off due to distortion of the inner shell 4 and the outer shell 3, and the claw-like bodies 91
can stop movement in the short axis direction.

The locking device shown in FIG. 5 can withstand a higher load than the locking devices shown in FIGS. 4(b) and (c), so it is particularly placed in the middle of the backrest portion in the vertical direction. Locking tool (
It is preferable to use it as 50) in FIG.

The claws 11, L-shaped bodies 12, and claw-shaped bodies 91 that constitute such locking tools 20, 30, . . . , 60 are as shown in the figure.
The outer shell 3 may be formed on the outer shell 3.
This is preferable for the appearance of the chair because it often forms the rear part of the backrest.

Furthermore, the claws 11, the L-shaped bodies 12, and the claw-shaped bodies 91 may be attached after the outer shell 3 is molded (or they may be molded simultaneously with the molding of the outer shell 3).

Among such locking devices, the locking device shown in FIG. 4('a) is
There are 2 to 6, especially about 5, locking devices on the upper part of the backrest shown in FIG. 4(b), (c) and/or FIG.
2 to 4 pieces, especially 4 pieces, from the middle to the bottom of the backrest in the vertical direction
By symmetrically attaching the outer shell 3 and the inner shell 4, the upper part of the backrest part 1 can be easily tilted relative to the lower part.

In addition, as shown in Fig. 2, the shell structure should have a substantially S-shape in which the substantially central part of the backrest protrudes forward, in order to be able to sufficiently withstand rearward warping loads, etc. can. Furthermore, between the backrest part and the seat part, there is a second
As shown in the figure, the concave shape with the tip protruding rearward can sufficiently withstand expansion, contraction, bending, etc. caused by tilting of the backrest.

In the chair shown in FIG. 2, the back support rod 76 is provided inside the shell structure, but the back support rod 76 may be provided outside the shell structure, that is, on the outside of the outer shell 3. good.

Further, the shell structure corresponding to the backrest portion and the shell structure corresponding to the seat portion may be separated.

Although the chair of this embodiment described above has the leg post 70, the present invention can also be applied to a chair that does not have the leg post 70.

(Effects of the Invention) According to the chair of the present invention, although the backrest portion and the seat portion are movable, the internal mechanism such as the back base is substantially covered by the shell member, so that the appearance and provides a good fit for the user.

In addition, since the chair of the present invention can bend the upper part of the backrest part backward with respect to the lower part, the movement of the backrest part and the seat part can be matched with each other, allowing the user to perform various tasks while working or resting. I can follow your posture.

In particular, when the user leans the upper part of the back against the upper part of the backrest part, the user can easily take a deep and comfortable posture.

[Brief explanation of the drawing]

1 is a side view and a partial sectional view of a chair according to an embodiment of the present invention, FIG. 2 is a sectional view showing the shell structure and internal mechanism of the chair shown in FIG. 1, and FIG. 3 is a sectional view of the chair shown in FIG. 2. FIG. 4 is a partial front view of the shell structure constituting the backrest portion viewed from the direction of arrow E in FIG.
A cross-sectional view of plane C and FIG. 5 are explanatory diagrams showing other examples of the locking device disposed from the middle to the lower part of the backrest. In the figure, 1...backrest part, 2...seat part, 3.4...shell member forming the shell structure of the chair, 20.30. ... ・Latching tool.

Claims (1)

[Claims] 1. A chair with a backrest, characterized in that the chair has an internal mechanism that satisfies the following [I] and a structure of the backrest that satisfies the following [II]. . [I] Internal mechanism (i) Seat base; (ii) Support base; (iii) Below the seat base, supported by the support base in the front-rear direction of the seat base, a balance member provided with a support rod; (iv) supporting the seat base so as to be movable in the front-rear direction, and distributing the load on the seat base to application point parts that sandwich the fulcrum part of the balance member; When the back support rod tilts rearward about the fulcrum part of the balance member, the backward tilting movement of the balance member is controlled by the seat support part, and the forward movement of the seat base is controlled by the seat support part. and (v) a mechanical elastic body that returns the seat base and the backrest to the chair's original rest position via the force transmission means. [II] Structure of backrest part The backrest part including the back support rod of the internal mechanism [I] is 2
The shell structure includes a shell structure formed by integrally assembling a plurality of elastic shell members with a plurality of locking devices arranged around the periphery, and among the locking devices of the shell structure corresponding to the backrest portion. , when the shell structure is tilted rearward, the locking tool at least in the middle of the shell structure in the vertical direction
The structure allows for misalignment between the two shell members, and when the user leans on the backrest, the upper part of the backrest can elastically tilt backwards relative to the lower part in response to the load. be. 2. The locking tool at least in the middle of the shell structure in the vertical direction is such that the L-shaped body protruding from one shell member loosely inserts into the through hole provided in the other shell member, and 2. The chair with a backrest according to claim 1, wherein the edge of the through hole of the other shell member engages with the claw portion of the letter-shaped body. 3. The shell structure corresponding to the backrest portion includes a back support rod that extends halfway in the vertical direction, and the shell structure is tiltable rearward about the upper end of the back support rod as a fulcrum. The chair with a backrest described in item 1 or 2.