Chairs and seats – Bottom or back – Cushioned
Reexamination Certificate
2000-09-19
2001-10-16
Nelson, Jr., Milton (Department: 3636)
Chairs and seats
Bottom or back
Cushioned
Reexamination Certificate
active
06302487
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a seat capable of absorbing forces that act on a seat occupant and enhancing the posture-retaining properties by employing a three-dimensional net having a large hysteresis loss and a high damping capacity.
2. Description of the Related Art
Conventional automobile seats generally include spring members attached to a seat frame, a pad material such as a foamed material, rocking material, or cotton placed thereon, and a skin such as a vinyl leather, woven cloth, or leather covered thereon.
Japanese Laid-open Utility Model Publication (unexamined) No. 5-72250 discloses a support structure for a seat wherein a stretch cloth having lateral stretch properties is fastened to opposite sides of a generally rectangular support frame, and a pad material is placed on the stretch cloth. Alternatively, in place of the stretch cloth, a generally flat support member called “PULLMAFLEX” is fastened to the opposite sides of the support frame via a plurality of coil springs.
Japanese Laid-open Patent Publication (unexamined) No. 6-55961 discloses a seat of a structure having a spring member called “Wire grid suspension” fastened to opposite sides of a support frame via a plurality of coil springs, and a pad material placed on the spring member.
In order to enhance the damping capacity or shock-absorbing properties, those in which a viscoelastic material is embedded in the pad material have been proposed.
On the other hand, seats other than automobile seats generally include a pad material placed on the frame and covered with a skin, and some of them also include spring members for enhancing the cushioning characteristics.
Although the spring members or the pad material acts to provide desired cushioning characteristics, conventional seats are mostly thick, heavy and costly.
Furthermore, In the automobile seats, when an acceleration is applied to the body of the seat occupant, a reaction force is created by the pad material or spring members, and a relative displacement between the thoracic vertebra and the pelvis causes a burden on the lumbar. In addition, slippage of the hip following rotation of the pelvis changes the posture and, hence, muscles are used to retain the posture, giving rise to muscle fatigue or lower back pain.
Because the support structure disclosed in Japanese Laid-open Utility Model Publication No. 5-72250 or the seat disclosed in Japanese Laid-open Patent Publication No. 6-55961 employs an elastic member having a small hysteresis loss, the vibration transmissibility is improved in a high-frequency region, but it is difficult for the seat to sufficiently reduce a resonant peak in a low-frequency region and to absorb an acceleration applied to the human body.
SUMMARY OF THE INVENTION
The present invention has been developed to overcome the above-described disadvantages.
It is accordingly an objective of the present invention to provide a seat having a three-dimensional net that is superior in vibration-absorbing properties and in inertia force-absorbing properties and capable of providing a superior body pressure distribution and following a change in posture to desirably support the pelvis and the spinal column.
Another objective of the present invention is to provide the seat of the above-described type which is thin, light and inexpensive.
In accomplishing the above and other objectives, the seat according to the present invention includes a seat cushion frame, a seat back frame mounted to the seat cushion frame, and a first three-dimensional net having upper and lower mesh layers and a pile layer having a large number of piles for connecting the upper and lower mesh layers. The first three-dimensional net is stretched over substantially an entire region of the seat cushion frame and the seat back frame, thereby forming a seat cushion and a seat back. The first three-dimensional net has a fixed end at a front end portion of the seat cushion and another fixed end at an upper end portion of the seat back. The seat according to the present invention also includes a first tension member attached to the first three-dimensional net at a location adjacent to a central portion thereof for imparting tension thereto, and a second tension member attached to another portion of the first three-dimensional net for fastening the first three-dimensional net to at least one of the seat cushion frame and the seat back frame.
This seat is of a vibration-absorbing structure utilizing a relative displacement between the seat back and the seat cushion. Also, this seat is light and inexpensive, requires a reduced space, and provides a superior body pressure distribution, compared with the conventional seat comprised of urethane and/or springs.
Furthermore, the provision of a hammock structure wherein the three-dimensional net of a high damping material has fixed ends at a front end portion and an upper end portion does not allow the pelvis to rotate even if the seat occupant sits thereon for a long time. A change in posture of the seat occupant is followed by a change in the pile layer and a change in external shape of the three-dimensional net, making it possible to softly support the flexible pelvis.
Advantageously, the seat cushion frame and the seat back frame are selectively covered with a pad material, which is in turn covered with a skin, making it possible to provide a soft riding comfort without any feeling of foreign substances.
Each of the first and second tension members includes one of a highly elastic three-dimensional net, a metal spring, and a stretch material made of rubber. Such tension members act to strengthen the spring properties and absorb high-frequency vibrations by creating an anti-phase.
The seat may further include a second three-dimensional net laminated on the first three-dimensional net. The laminated structure of the three-dimensional nets provides soft spring properties while strengthening the damping properties, making it possible to absorb vibrations and provide a soft riding comfort.
A pad material may be interposed between the first and second three-dimensional nets to absorb the high-frequency vibrations.
REFERENCES:
patent: 5013089 (1991-05-01), Abu-Isa et al.
patent: 6152534 (2000-11-01), Maeda et al.
Asano Akihito
Chizuka Kazuyoshi
Fujita Etsunori
Fujita Hitoshi
Kawasaki Seiji
Delta Tooling Co., Ltd.
Jr. Milton Nelson
Wenderoth , Lind & Ponack, L.L.P.
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