JPH0795967B2 - Chair with backrest - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a chair with a backrest, and more specifically, a chair in which a seat portion moves forward while a backrest portion tilts backward.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chair with a backrest in which the upper side of the backrest can be tilted rearward with respect to the lower side at an arbitrary position of the backrest, so that the user can take various rest postures.

(Prior Art) In a chair in which a user sits for a long time, such as a work chair, the user takes various postures because he is tired if he takes only one posture. It is desirable that the seat part and the backrest part easily follow the above. Further, when resting, the backrest is generally leaned against the backrest, and it is desirable that the seat and the backrest are deeper and the chair easily moves following the movement of the user during the rest.

Furthermore, when not in use, there is a demand for a chair that allows the seat and backrest to return to the standard position, which is the original form of the chair.

A conventional chair of this type is known in which, for example, a back portion and a seat portion are supported by springs or the like, and when the user rests, the back portion and the seat portion are tilted rearward.

Further, the backrest and the seat are connected to each other through a hinge joint at the lower end of the backrest and the rear end of the seat, and the backrest is rotated in the front-rear direction by a horizontal support shaft in the vertical midway portion. A chair is known in which a crossbar is freely attached to a frame, and further, both ends of a crossbar fixed to the lower surface of the seat are movably guided along a long hole of a seat guide provided on the front end side of the frame ( JP-A-61-247418). According to this chair, when the user leans on the backrest at rest, the backrest tilts rearward, and the seat moves forward and upward in conjunction with the rearward tilting of the backrest. It can be taken.

However, the above-mentioned conventional chair has the following problems.

That is, in the former chair, the back portion and the seat portion tilt rearward according to the movement of the user, but at that time, the angle between the back portion and the seat portion does not change, and Since the seat does not move forward, the degree of freedom to take a working posture or a resting posture is limited accordingly.

Further, when the backrest portion and the seat portion tilt, the center of gravity moves rearward, which may make it easy to fall backward.

Further, in the above-mentioned chair, the load applied to the backrest part varies depending on the weight of the user's weight, and thus initial adjustment for adjusting the strength of the spring before use is indispensable according to the user's weight. It is not always easy for the user to perform this initial adjustment optimally. Also, since the strength of the spring is set according to the weight of the user, it can generally be used only as a chair dedicated to the user, and is used by an unspecified number of people, for example, a conference room. It is not suitable as a chair for people.

In the latter chair, when the backrest is tilted rearward, the upper side of the backrest tilts backward, but the lower side of the backrest moves backwards. Therefore, when the user leans his / her entire back on the backrest to take a resting posture, the movement of the back of the user does not match the movement of the backrest, which causes a feeling of discomfort.

Also, since the horizontal support shaft is located midway in the vertical direction of the backrest, a person with a light weight, a person with a low sitting height, etc. does not apply the necessary load to the backrest and tilts the backrest backward. There is a problem that becomes difficult.

Furthermore, since the seat part is connected to the lower end part of the backrest part, although the seat part moves forward, it does not spread to the depth of the seat space, and it is difficult to take a comfortable resting posture. is there.

(Background Art) Therefore, regarding a chair in which the drawbacks of the conventional chair with a backrest are improved, the present inventors have previously described Japanese Patent Application No. 62-193392, Japanese Patent Application No. 62-193393, and Japanese Patent Application No. 62-193393. Wish sho 62-193394
No. 62-193395, and Japanese Patent Application No. 62-193395.

Such a chair is a chair with a backrest, a seat base,
Below the seat base and the seat base, the balance member, which is supported by the support base in the front-back direction of the seat base and has a back support rod at the rear, and the seat base are moved in the front-back direction. It includes a seat receiving portion that supports the seat freely and divides the load on the seat base into action points that sandwich the fulcrum portion of the balance member, and the back support rod is rearward about the fulcrum portion of the balance member. Force transmitting means for converting the backward tilting movement of the balance member when tilting to the forward moving movement of the seat base through the seat receiving portion, and the seat base and the back support through the force transmitting means. And a mechanical elastic body for returning the rod to the original rest position of the chair.

This chair is a chair in which the seat part moves forward while the back part tilts backward, and the back part and the seat part can be easily moved to follow the movements of the body, and the resting posture can be easily taken. It is a thing.

In such a chair, in order to improve its appearance and to fit the backrest part to the user's back, structural members that form internal mechanisms such as a balance member, a seat base, and a back support rod are shell structures. It would be convenient if it could be substantially encapsulated in.

However, in this type of chair, the seat moves forward as the backrest tilts rearward, that is, the seat space between the seat and the backrest greatly opens. It is difficult to wrap.

(Object of the Invention) As a result of various studies to solve the above problems, the inventors of the present invention have found that the problem can be solved by assembling the two shell members constituting the shell structure so as to allow mutual deviation. did.

That is, the object of the present invention is, despite the fact that the backrest part and the seat part is a chair that moves, the seat part base, the back support rod, the structural member such as the balance member can be substantially encapsulated by the shell member,
Not only can the appearance and fit be improved, but the upper part of the shell structure, that is, the upper part of the backrest, can be bent rearward with respect to the lower part of the shell structure, so that a chair with a deeper resting posture can be obtained. To provide.

(Means for Solving the Problems) The above object is achieved by the following configurations.

That is, the chair with a backrest is characterized in that the chair has an internal mechanism satisfying the following [I] and a structure of a backrest portion satisfying the following [II].

[I] Internal mechanism (i) Seat base, (ii) Support base, (iii) Below the seat base, is supported by the support base in the front-back direction of the seat base, and is supported by the back at the rear. A balance member provided with a supporting rod, and (iv) the seat base is movably supported in the front-rear direction, and the load on the seat base is divided into action points that sandwich the fulcrum of the balance member. Including a seat receiving portion, a forward tilting movement of the seat base through the seat receiving portion when the back support rod tilts rearward about the fulcrum of the balance member as a center. And (v) a mechanical elastic body that returns the seat base and the back support rod to the original rest position of the chair via the force transmission means.

[II] Structure of backrest part The backrest part including the back support rod of the internal mechanism [I] is integrally assembled by a plurality of fasteners around which two elastic shell members are arranged. When a shell structure including a shell structure formed with the shell structure and corresponding to the backrest part, at least a middle middle part of the shell structure is tilted rearward. The structure that allows the deviation between the two shell members,
When the user leans against the backrest, the upper side of the backrest can elastically tilt rearward with respect to the lower side with respect to the load.

In such a chair with a backrest, at least the vertical middle part of the shell structure has the L-shaped body projecting from one shell member loosely inserted into the through hole provided in the other shell member. At the same time, the claw portion of the L-shaped body has a structure in which the through-hole edge portion of the other shell member is engaged, and / or the shell structure corresponding to the backrest portion extends to an intermediate portion in the vertical direction. Since the shell structure includes the back support rod and the shell structure is tiltable rearward with the vicinity of the upper end portion of the back support rod as a fulcrum, the upper side of the backrest can be tilted more easily with respect to the lower side.

The “internal mechanism” in the present invention means that the structural member forming the mechanism is substantially covered by the shell structure, and a part of the structural member, for example, the back support rod is the shell structure. It may be provided outside.

(Operation) In the chair with the backrest of the present invention, when the user leans on the backrest and applies a load to the backrest, the seat back moves forward while the seatback tilts backward due to the internal mechanism of the chair. The seat space between the seat and the seat can be expanded, and a resting posture can be taken.

At that time, the shell structure causes a necessary displacement between the two shell members, and moves while following the movements of the backrest and the seat while maintaining the shell structure.

Further, when the user leans the upper part of the back against the upper part of the backrest to take a more comfortable posture, the shell structure tilts backward with the upper end of the back support rod as a fulcrum while maintaining the shell structure.

At this time, the upper back is supported by receiving an appropriate reaction force from the shell structure according to the load applied by the user, so that a deep comfortable posture can be taken.

In this way, the backrest can be tilted rearward at any angle, and the seat can be moved forward in conjunction with the rearward tilting of the backrest, as well as any position of the backrest. The upper side of the backrest can be tilted rearward with respect to the lower side, so that the user can take various rest postures.

Also, the backrest is substantially encapsulated by the shell structure, which increases the fit.

Furthermore, when the user stands up 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 the shell member, while the entire backrest and the seat are of the internal mechanism. The chair is returned to the original standard position by the urging force of the mechanical elastic body.

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

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

In the figure, 1 is a backrest part, 2 is a seat part, 3 and 4 are shell members constituting a shell structure of a chair, and 5 is a cushion part.

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

This internal mechanism consists of a fixed frame 71 which is a support base at the upper end of the pedestal 70.
Is fixed. The fixed frame 71 has its front end side gently rising toward the front, and its rear end side rising 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-back direction of the seat base 73. It is worn. 74 is the rotation axis (fulcrum).

Reference numeral 76 is a back support rod 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 fixed frame 71 on the front end side by a shaft 78 at an L-shaped bent portion. One end of one end of the L-shaped link 77 is pivotally attached to the front side of the seat base 73 by a shaft 79.
The other link end of the character-shaped link 77 is connected to the front end of the balance member 72 by a pin 80 and a long hole 81. That is,
A pin 80 projecting from one end of the L-shaped link 77 is loosely fitted in a long hole 81 formed in the front end of the balance member 72 and extending in the front-rear direction.

Needless to say, the pins may be provided on the balance member 72 and the elongated holes may be provided on the L-shaped link 77 side.

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

The L-shaped link 77 and the link plate 82 form a seat receiving portion. Further, the L-shaped link 77 is connected to the tip of the balance member 72 by the pin 80 and the long hole 81, thereby forming a force transmitting means for moving the seat base 73 forward.

Reference numeral 85 denotes a tension spring for returning and balancing, which is a shaft 79 of the L-shaped link 77 and a fixed shaft 86 provided on the rear end side of the fixed frame 71.
And the seat 73 is urged to the original standard position as a chair, and the L-shaped link 77 and the balance member are provided.
Through 72, the back support rod 76 is biased to the original standard position (standing position) as a chair.

As described above, when the seat base 73 and the back support rod 76 are biased to the standard position by the tension spring 85 and are stationary, the line connecting the shaft 78 and the shaft 79 of the L-shaped link 77, and the link The line connecting the shaft 84 and the shaft 83 of the plate 82 is set to incline rearward and upward. Also at this time L-shaped link
The line connecting the shaft 78 of the 77 and the pin 80 is inclined rearward and downward.

On the other hand, the shell structure is one in which the outer shell 3 and the inner shell 4 are integrally assembled by a locking tool 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 corresponds to the corresponding inner shell 4
Is fixed to the upper surface of the seat base 73 on the lower surface of
In the space of the shell structure on the backrest side, the back support rod 76 has entered up to a midway point. 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, when the chair of this embodiment leans against the backrest 1, the seatback 2 moves forward while the backrest 1 tilts rearward, and the upper side of the backrest 1 with respect to the lower side. It can be tilted backwards.

That is, the respective shell structures corresponding to the backrest and the seat can follow the movement of the internal mechanism, and the upper part of the shell structure corresponding to the backrest is elastically rearward with the vicinity of the upper part of the back support rod 76 as the center. It can be bent.

That is, when the shell structure is deformed, the inner shell 4 and the outer shell 3 have different degrees of deformation. Is configured to allow a shift between the shell members, the shell structure can easily follow the movement of the internal mechanism, and the shell structure corresponding to the backrest can be smoothly bent.

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

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

As is apparent from FIG. 2, the inner shell 4 is formed so that its lateral shape is substantially L-shaped, and a fitting edge 6 protruding in the direction of the shutter shell 3 is formed on the outer periphery thereof.

The outer shell 3 is shaped so as to be fitted into the inner shell 4 from the rear, and a predetermined space is formed with respect to the inner shell 4 near the center as shown in the drawing.
The peripheral portion is shaped to fit inside the fitting edge 6 of the inner shell 4. For this reason, the outer shell 3 has a shape curved toward the inner shell 4 near the outer peripheral portion thereof.

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 to be small, and this portion is easily bent backward.

In such a shell structure, the outer shell 3 and the inner shell 4 of the portion that wraps the seat base 73 of the internal mechanism are
It is fixed by screws 87 etc. around its outside, while
Both shells on the backrest side are shown in FIG.
… They are assembled together so that they can be displaced by 60.

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

The fasteners 50 and 60 are the inner shell 4 of the outer shell 3.
Is formed on an L-shaped body 12 projecting in an L-shape on the surface opposite to the back surface of the backrest 1
Facing upward. The L-shaped body 12 projects into 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 portion of the through hole of the inner shell 4 is provided inside the claw portion of the L-shaped body 12. I am involved. It will be appreciated that this allows the inner shell 4 and the outer shell 3 to be assembled together and allows for misalignment of both shells when the upper portion of the shell structure is bent backward.

The deviation will be described later.

The locking tools 20 and 30 for locking 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 projection direction of the claw portion of this L-shaped body is L-shaped. It is opposite to the protruding direction of the claw portion of the body 12. Therefore,
As can be seen from FIG. 4 (a), the upper edge of the outer shell 3 is engaged with the fitting edge 6 of the inner shell 4 to form an L-shaped body.
Since the peripheral portion of the through hole 10 provided in the inner shell 4 is engaged with the claw portion facing downward of 11, the upper portions of the inner shell 4 and the outer shell 3 are fitted with the L-shaped body 11 and the fitting edge. By the action of 10, it is practically almost fixed.

The locking tool 40 is also formed in an L-shape, and the projection direction of the claw portion of the locking tool 40 is directed to the center line direction of the shell structure.

Next, the operation will be described.

First, the internal mechanism of this embodiment will be described. When the user sits down on the chair in the standard position shown in FIG. 2, the load is transferred through the seat base 73 to the rotation shaft 74 (fulcrum) of the balance member 72. It is divided into action points before and after. The load due to this component force is
One imparts a clockwise moment about the pivot shaft 74 to the balance member 72 via the link plate 82, and the other imparts a counterclockwise moment via the L-shaped link 77.

If the counterclockwise moment is greater, the balance member 72
Rotates counterclockwise about the pivot shaft 74, but a stopper (not shown) acts so that the seat base 73 and the back support rod 76 are located at the standard position.

If the clockwise moment is larger, the balance member
Although 72 tries to rotate clockwise, the tension spring 85 acts so that the standard state is maintained even when no load is applied to the back support rod 76.

In this case (and also in the resting posture described later), the load is divided around the fulcrum of the balance member 72, and the balance is offset by the balance action. The above-mentioned clockwise moment is relatively small.

Therefore, the tension spring 85 does not have to be a very strong spring.

On the contrary, the strength of the tension spring 85 does not have to be so large, which has the following advantages.

That is, even when working, the worker may take a working posture in which he leans slightly against the backrest, but in that case, since the strength of the tension spring 85 is not so large, the back support rod is not so strong.
76 tilts backwards.

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

This can be done by both heavy and light people with little difference. That is, the balance of the load around the fulcrum portion is offset by the balance action of the balance member 72 for both heavy and light people, so that the weight of the tension spring 85 is not so large even for light people. In contrast, the back support rod 76 can be easily tilted.

Next, when shifting to a rest state, the user intentionally leans against the backrest and applies a load to the back support rod 76, and the tension spring 85
The back support rod against the tensile force of
The 76 is tilted rearward about the pivot shaft 74.

Also in this case, the back support rod 76 can be tilted backward with almost no difference between a heavy person and a light person.

That is, in the case of a heavy person, a large load is applied to the back support rod 76, and in the case of a light weight person, a relatively small load is applied to the back support rod 76. The load acting on the back part in the direction opposite to the load applied to the back support rod 76 is larger in the case of a heavier person than in a lighter person, and is offset by the balance action. It is possible for both heavy and light people to lean the back support rod 76 rearward with a similar degree of leaning.

When the back support rod 76 is tilted backward, the tip end side of the balance member 72 is circularly rotated upward about the rotation shaft 74, whereby L
The character-shaped link 77 rotates about the shaft 78 to the left in FIG. That is, the link piece connecting the shaft 78 and the shaft 79 of the L-shaped link 77 gradually stands up from the rearward inclined position shown in FIG.
Rotate beyond the standing position to a position slightly inclined forward. Therefore, the seat base 73 moves forward as the L-shaped link 77 rotates. At that time, the front side of the seat base 73 is slightly raised.

On the other hand, the link plate 82 also moves along with the forward movement of the seat base 73.
The shaft 84 is rotated about the shaft 84 from the rearwardly inclined position, beyond the standing position, and further to a position slightly inclined forward. By the way, the shaft 84 is rotated by the rotation of the balance member 72.
It makes an arc rotation about and moves slightly lower than the standard position. Therefore, the rear side of the seat base 73 interlocks with the rearward tilting of the back support rod 76 and moves slightly forward while moving forward.

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

By the way, when the link piece of the L-shaped link 77 and the link plate 82 rotate from the state of being tilted rearward to the standing position as described above, the load applied to the link piece and the link plate 82 by the user. Acts as one of a kind of resistance force to the rearward tilting of the back support rod 76. The resistance force due to the load at this time prevents the back support rod 76 from suddenly falling backward when a load is applied to the back support rod 76. Especially, as described above, the strength of the tension spring 85 is not so great,
Further, since the pulling force is particularly small in the initial stage of extension, the resistance force effectively acts to prevent the back support rod 76 from tilting at once.

Next, as the back support rod 76 tilts, the load on the back support rod 76 gradually increases, while the above-mentioned link piece, link plate
As 82 stands, the above-mentioned resistance decreases.

Therefore, the above-described resistance force and the tensile force of the tension spring 85 and the above-mentioned gradually increasing load on the back support rod 76 are balanced at a certain position. The tension spring 85 described above also functions as a balancer in that case. Of course, muscle strength such as abdominal muscle strength of the user also acts, and the back support rod is at a position where these strengths are balanced.
The tilting of the 76 to the rear stops, and a resting posture can be taken at this stop position. When taking this resting posture, as described above, the back support rod
Since the seat 76 tilts rearward about the rotating shaft 74 located below the seat base 73 and the seat base 73 moves forward,
The seating space expands back and forth, giving you a relaxed and resting posture. Further, when the seat base 73 moves forward, as described above, the rear side of the seat base 73 moves forward but slightly sinks, so the movement of the buttocks and the seat base 73 when trying to take a resting posture. The movement is almost the same, and you can shift to a resting posture without feeling any discomfort.

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

To return to the standard state, when the user stands up or stands up from the chair, the seat base 73 and the back support rod 76 return to the standard position by the tensile force of the tension spring 85.

The movement of the seat base 73 and the back support rod 76 is assembled so that the shell structure is connected to the seat base 73 and the inner shell 4 is allowed to be displaced. The outer shell 3 makes it smooth.

As described above, the chair of this embodiment can take various postures in addition to the shell structure following the movement of the internal mechanism, and the upper portion of the backrest portion further tilting with respect to the lower portion.

That is, when the user leans the upper part of the back against the upper part of the backrest 1 and tries to take a more comfortable posture, the shell structure will resist the rigidity of the shell structure and the back support rod 76.
It is bent backward with the upper end as a fulcrum.

The shell structure adopted in this embodiment can follow the movement of the internal structure, and the upper part of the shell structure corresponding to the backrest is bent backward with respect to the lower part. This is possible because the locking tool allows a shift between both shells while the three and 3 are assembled together.

When the back support rod 76 of the internal mechanism tilts rearward and the seat base 73 moves forward, or when the upper portion of the backrest 1 is bent backward with respect to the lower portion, the load is applied to the outer shell 3
To the inner shell 4, and to the inner shell 4 in the extending direction. Since the inner shell 4 and the outer shell 3 are fixed to each other at the upper and lower portions as described above, the compressive force on the outer shell 3 must act in a direction in which the curve A of the outer shell 3 is further curved slightly outward. Will be understood. Therefore, this allows the inner shell 4 and the outer shell 3 to be bent. As is apparent from FIG. 2, the deformation of the inner shell 4 and the outer shell 3 causes the inner shell 4 to move in the direction of arrow G in the figure when the seat portion moves forward while the backrest portion tilts backward. In the direction of I, the outer shell 3 is compressed and extended in the direction of arrow H, respectively, and when the upper side of the shell structure corresponding to the backrest is bent backward with respect to the lower side, the seat base 73 Since there is no forward movement, the inner shell 4 moves in the direction of arrow G in the figure, and the outer shell 3
Are expanded and compressed in the directions of arrows H, respectively.

Therefore, a displacement occurs between both shells, and this displacement is allowed by the locking members 20, 30, ..., 60, so that the entire shell structure corresponding to the backrest portion has a uniform tilt angle. It can be smoothly tilted rearward, or the upper side of the shell structure can be smoothly bent with respect to the lower side.

What should be noted here is that the inner shell 4 and the outer shell 3 are deformed while maintaining their shell structures. That is, both shells are fixed at the upper part and the lower part, and even if there is a deviation in the middle part, the two shells are dislocated while being locked by the locking members 20, 30, ..., 60. Is.

In this way, since the shell structure is deformed while being held, the user needs to use the appropriate reaction force of the shell structure, especially when the upper side of the shell structure corresponding to the backrest is bent backward with respect to the lower side. The upper side of the backrest can be tilted rearward with respect to the lower side while receiving the force, and when the external force is removed, the backrest can easily return to its original position.

The upper portions of both shells that are subject to such deformation are substantially fixed by the structure of the L-shaped body 11 and the fitting edge 6 as described above, but in reality a slight deviation occurs. The locking tools 20 and 30 can tolerate this slight deviation due to the above-mentioned configuration. Although the upper parts of both shells may be completely fixed with screws, etc., when the shell structure tries to tilt or bend backward, a large force of extension and compression is applied to the upper parts of both shells, causing a large displacement action. Works, so
There is a problem in durability with the screw stopper, and it is rather preferable to adopt a structure that allows a slight deviation as described above.

In addition, the L-shaped body 12 of the locking stationery 50, 60 is shown in FIG.
As shown in (c), ribs 13 are provided on a part of the ribs 13 to reinforce the ribs, whereby the thickness of the plate forming the L-shaped body 12 can be made as thin as possible.

Further, the locking tool shown in FIG. 5 can be adopted as a locking tool in place of FIGS. 3 (b) and 3 (c).

As shown in FIG. 5 (i), in the locking tool shown in FIG. 5, a slit-shaped opening 92 is formed in the inner shell 4 substantially parallel to the outer periphery thereof and is pushed into the opening 92. A claw-shaped body 91 is formed on the outer shell 3.

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

When such a claw-like body 91 is pushed into the opening 92, it can move in the direction of the arrow as shown in FIG. 5 (ii), so that the upper side of the backrest portion is lower than the lower side. A shift between the shells caused by tilting backward can be allowed.

In addition, as shown in FIG.
By doing so, it is possible to easily push in the claw-shaped body 91, and the claw-shaped body 90 is disengaged by the strain of the inner shell 4 and the outer shell 3 after the claw-shaped body 91 is pushed in. And the movement of the claw-shaped body 91 in the short axis direction can be stopped.

The locking device shown in FIG. 5 can withstand a high load as compared with the locking device shown in FIGS. 4 (b) and 4 (c), and is therefore arranged especially in the vertical center of the backrest. It is preferably used as a lock (50 in FIG. 3).

Claws 11, L that constitute such locking tools 20, 30, ..., 60
As shown in the figure, it is preferable that the character-shaped body 12 and the claw-shaped body 91 are formed on the outer shell 3 in terms of the appearance of the chair because the outer shell 3 often constitutes the rear portion of the backrest portion.

Further, the claw 11, the L-shaped body 12, and the claw-shaped body 91 may be attached after the outer shell 3 is tilted, or may be formed simultaneously with the molding of the outer shell 3.

Among such fasteners, the fastener shown in FIG. 4 (a) has 2 to 6 pieces, especially about 5 pieces on the upper portion of the backrest, and FIG. 4 (b), (c) and / or The locking tool shown in Fig. 5 is
2 to 4, especially 4 from the middle of the backrest up and down
The outer shell 3 and the inner shell 4 can be easily assembled and the upper side of the backrest portion 1 can be easily tilted with respect to the lower side by having the individual pieces symmetrically attached.

Further, as shown in FIG. 2, the shell structure may have a substantially S-shape in which the substantially central portion of the backrest portion projects forward, so that the shell structure can sufficiently withstand a backward warping load and the like. it can. Further, a second portion is provided between the back portion and the seat portion.
As shown in the figure, the tip end having a concave shape protruding rearward can sufficiently withstand expansion and contraction, bending and the like due to 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, outside the outer shell 3. Good.

Further, the shell structure corresponding to the backrest part and the shell structure corresponding to the seat part may be divided.

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

(Effect of the Invention) According to the chair of the present invention, although the backrest portion and the seat portion are movable chairs, the internal mechanism such as the back base is substantially encapsulated by the shell member. And the fit of the user is good.

Further, in the chair of the present invention, since the upper part of the backrest can be bent backward with respect to the lower part, the movement of the backrest and the seat causes a variety of movements, which results in a wide variety of changes during work and rest of the user. Can follow any posture. Particularly, when the user leans the upper part of the back against the upper part of the backrest, the user can easily take a deep comfortable posture.

[Brief description of drawings]

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 a shell structure and an internal mechanism of the chair shown in FIG. 1, and FIG. 4 is a partial front view of the shell structure forming the backrest viewed from the direction of arrow E in FIG. 4, and FIG.
FIG. 5 is a cross-sectional view of the C surface, and FIG. 5 is an explanatory view showing another example of the locking device arranged from the middle part to the lower part of the backrest part. In the figure, 1 ... back portion, 2 ... seat portion, 3,4 ... shell members forming a shell structure of a chair, 20,30, ..., 60 ...

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michiyoshi Katagiri 137 Takano Stock Association, Miyata-mura, Kamiina-gun, Nagano In-house (72) Inventor Yoichi Suzuki, 6-1, 1-1, Oimari Minami, Higashinari-ku, Osaka, Osaka In-company (56) Reference JP-A-63-279810 (JP, A) JP-A-1-37913 (JP, A) JP-A-1-37912 (JP, A) JP-A-63-277013 (JP, A) ) JP-A 63-279809 (JP, A) JP-A 63-277012 (JP, A) JP-A 63-161905 (JP, A) JP-A 62-57518 (JP, A) JP-A 61- 247418 (JP, A) JP Unexamined Patent Publication No. 1-139013 (JP, A) Actually opened 60-158445 (JP, U) Actually opened 62-153936 (JP, U) Actually opened 61-158244 (JP, U) Actual Open Sho 61-179946 (JP, U) Actual Open Sho 62-196047 (JP, U)

Claims (3)

[Claims] 1. A chair with a backrest, wherein the chair has an internal mechanism satisfying the following [I] and a structure of a backrest satisfying the following [II]. [I] Internal mechanism (i) Seat base, (ii) Support base, (iii) Below the seat base, is supported by the support base in the front-back direction of the seat base, and is supported by the back at the rear. A balance member provided with a supporting rod, and (iv) the seat base is movably supported in the front-rear direction, and the load on the seat base is divided into action points that sandwich the fulcrum of the balance member. Including a seat receiving portion, the rearward tilting movement of the balance member when the back support rod tilts rearward about the fulcrum portion of the balance member, the forward movement of the seat base through the seat receiving portion. And (v) a mechanical elastic body that returns the seat base and the back support rod to the original rest position of the chair via the force transmission means. [II] Structure of backrest part The backrest part including the back support rod of the internal mechanism [I] is integrally assembled by a plurality of locking members around which two elastic shell members are arranged. When a shell structure including a shell structure formed with the shell structure and corresponding to the backrest part, at least a middle middle part of the shell structure is tilted rearward. The structure that allows the deviation between the two shell members,
When the user leans against the backrest, the upper side of the backrest can elastically tilt rearward with respect to the lower side with respect to the load. 2. An engaging member at least in the vertical direction of the shell structure allows an L-shaped body projecting from one shell member to be loosely inserted into a through hole provided in the other shell member. The chair with a backrest according to claim 1, wherein the claw portion of the L-shaped body has a structure in which a through hole edge portion of the other shell member is engaged. 3. A shell structure corresponding to a backrest portion includes a back support rod extending up to a midway portion in the up-down direction, and the shell structure is tiltable rearward about a top end portion of the back support rod as a fulcrum. A chair with a backrest according to claim 1 or 2.