Chairs and seats – Bottom or back – Framework
Patent
1990-06-06
1992-04-07
Brown, Peter R.
Chairs and seats
Bottom or back
Framework
297301, 297421, A47C 312
Patent
active
051021960
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a chair provided with a backrest in which an inner shell and an outer shell are combined to form an integral body having a seat combined with a backrest.
BACKGROUND ART
There is known a chair of this type provided with a backrest and comprising an inner shell consisting of a seat portion and a backrest portion formed into an integral body, with an outer shell consisting of a plurality of sections fixed to the under surface and the back surface of the inner shell. In particular, in the conventional chair the outer shell is divided into at least a portion for a backrest to cover the back surface of the inner shell and a portion for a seat to cover the under surface of the seat portion of the inner shell. Particularly, in many of those chairs in which the motion of the seat relative to the leg is complicated, the outer shell for the seat is divided into a plurality of pieces, with a wide gap formed between the pieces. In some of the chairs the outer shell for the seat is fixed to both the inner shell and a supporting unit for supporting the inner shell.
However, with an outer shell divided into a seat portion and a backrest portion, it is difficult to provide the outer shell with a sufficient strength for the whole shell. In particular, the conventional outer shell has a function merely as a cover for covering the back and under surfaces of the inner shell, and the inner shell is so designed as to provide a structural strength of the seat and the backrest. The conventional inner shell is provided with various complex ribs for suppressing deformation and various cutouts for helping deformation, thereby to impart a required strength to each component member. However, there is a limit to imparting different degrees of strength to different parts of the inner shell which is an integral body. This poses a problem that there is little degree of freedom in design.
The primary object of the invention is to solve the above-mentioned problem by forming the seat portion and the backrest portion of the outer shell into an integral body.
Another object of the invention is to solve concrete problems posed by an outer shell formed as an integral body. The problems are as follows:
1 Outer shells of different shapes are required for accommodating supporting units of different types to be contained between the inner and outer shells, so that a plurality of large dies of different types need be prepared for forming outer shells.
2 If the outer shell is applied to a chair in which the seat shifts relative to a supporting unit, a wide gap is likely to remain between the outer shell and that portion of the supporting unit which comes out of the shell.
3 Since the outer shell itself functions as a member which bears a load, it is difficult to provide the backrest itself with a suitable resiliency. In particular, in conventional chairs, the outer shell for a backrest is fixed to the rear surface of the inner shell by engagement of pins with holes each having a claw for preventing the pin from falling off or by means of screws. If such an arrangement is used in the backrest portion of the outer shell of the invention, the flexibility of the backrest is likely to be lost.
4 With a chair provided with a backrest with little flexibility and without any particular measures, when the backrest is inclined rearwardly, the distance between the reference point of the sitting position which is the center of the load on the seat and the backrest point corresponding to the fifth lumbar vertebra of a person on the seat varies. In particular, in the chair which takes a reference position, even if the backrest point is set to an ideal position, when the backrest is inclined rearwardly by the user with his back against the backrest, the backrest point shifts upwardly relative to the back of the user, so that the user feels uncomfortable. Moreover, when the user repeatedly leans his back against the backrest and raises his back therefrom, the shirt, etc. worn by the user may be lifted up and the lower por
REFERENCES:
patent: 3669499 (1972-06-01), Semplonius et al.
patent: 3722954 (1973-03-01), Rey et al.
patent: 4088367 (1978-05-01), Atkinson et al.
patent: 4744603 (1988-05-01), Knoblock
patent: 4776633 (1988-10-01), Knoblock et al.
patent: 4836609 (1989-06-01), Hill
patent: 4892356 (1990-01-01), Pittman et al.
Ito Tunetaro
Kaneda Shinichi
Katagiri Miyoshi
Miyashita Masamitu
Sugano Takao
Brown Peter R.
Kokuyo Co. Ltd.
LandOfFree
Chair provided with a backrest does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Chair provided with a backrest, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chair provided with a backrest will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1890875