Chairs and seats – Movable back – Tiltable
Reexamination Certificate
2000-06-07
2001-12-04
Nelson, Jr., Milton (Department: 3636)
Chairs and seats
Movable back
Tiltable
Reexamination Certificate
active
06325457
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to improvements in a seat reclining system for a vehicle, and more particularly to a structure for reinforcing a base plate of the seat reclining system.
2. Description of the Prior Art
Modern automotive vehicles are equipped with a seat reclining system which adjusts the rotational position of a seat back of a vehicle seat forward or rearward in order that a vehicle occupant seated on the seat can ensure his optimum and comfortable posture. In a recent tendency in which weight-lightening of vehicular parts is being promoted to meet the requirement of weight-lightening of the vehicle, weight-lightening is required also for the seat reclining systems. In view of this, the thickness of a base plate of the seat reclining system is reduced as compared with a conventional one thereby accomplishing lightening of the seat reclining system.
More specifically, right-side and left-side base plates made of metal are fixed through suitable fixing members to a vehicle floor or fixed respectively to right-side and left-side seat slide devices fixed on the vehicle floor. A seat cushion of the vehicle seat is disposed between the base plates. Each base plate is disposed vertical to the vehicle floor. An arm plate is hingedly connected through a locking mechanism to each base plate. The seat back of the vehicle seat is installed to the arm plate. The locking mechanism is a control section for adjusting the inclination angle of the seat back. Accordingly, the base plate must have a sufficient strength to sustain a load applied to the seat back, so that the thickness of the material (metal plate) of the base plate has been conventionally increased thereby unavoidably increasing the weight of the seat reclining system.
There is one locking system for the seat reclining system, in which two locking mechanisms are respectively installed to the right-side and left-side base plates. Another locking system is arranged such that only one locking mechanism is installed to one of the right-side and left-side base plates so that the other base plate is formed as a freely movable hinge. Concerning the structure of the locking mechanism, hitherto one in which lock parts are assembled to the base plate is in the mainstream; however, recently one in which a unitized locking mechanism is assembled between the base plate and the arm plate has been used. In connection with the latter one, the arm plate is formed to have a reduced thickness and has a flange section along the periphery of the arm plate.
SUMMARY OF THE INVENTION
However, difficulties have been encountered in the above conventional seat reclining systems in which the thickness of the base plate is reduced to achieve weight-lightening of the seat reclining system. That is, the base plate having a reduced thickness is lowered in rigidity. Accordingly, when an excessive load is applied to the seat back, for example, in the event of a rear-end collision of the vehicle, the base plate receives not only a rearward load but also a flexural load in lateral directions due to the load of the vehicle occupant seated. Consequently, a concentrated stress is developed in the vicinity of the front side of a fixed portion (of the base plate) at which the locking mechanism is fixed. As a result, a deformation is produced between the fixed portion and an installation portion of the base plate to a seat slide device or the like, and therefore there is the possibility of the base plate falling down in the lateral directions.
In view of the above, it is an abject of the present invention to provide an improved seat reclining system which can overcome drawbacks encountered conventional seat reclining systems.
Another object of the present invention is to provide an improved seat reclining system in which a base plate can be effectively reinforced to be prevented from being deformed even in the event of a rear-end collision of a vehicle without affecting weight-lighting of the seat reclining system.
A further object of the present invention is to provide an improved seat reclining system in which a base plate is reinforced with a light-weight reinforcement plate which is formed with a flange section in conformity with a deformation plane along which the base plate deforms when an excessive load is applied to a seat back of a vehicle seat.
A seat reclining system according to the present invention is for a vehicle and comprises a locking mechanism having first and second axial sides. An arm plate is provided such that the first axial side of the locking mechanism is connected to the arm plate. A seat back of a vehicle seat is connected to the arm plate. A base plate is provided having first and second surfaces which are opposite to each other. The base plate includes an installation portion through which the base plate is connected to a vehicle floor. The base plate further includes a fixed portion having the first surface to which the second axial side of the locking mechanism is connected. Additionally, a reinforcement plate is provided including a main body section having first and second surfaces which are opposite to each other. The reinforcement plate further includes a flange section integral and extended from the main body section. The flange section extends generally perpendicular to a plane which passes through a first position located in front of the fixed portion of the base plate and a second position located behind the installation portion of the base plate. The plane is perpendicular to the surfaces of the base plate. The reinforcement plate is fixed to the base plate in a state where the first surface of the main body section is in contact with the second surface of the base plate.
The reinforcement plate preferably has a linear bead which extends generally vertically and has an axis which crosses the plane at an acute angle. Additionally, a return spring is preferably disposed between the reinforcement plate and the arm plate so as to rotatably biasing the arm plate. The return spring has an end section connected to the reinforcement plate. Here, the reinforcement plate has a through-hole through which an operation shaft of the locking mechanism passes. Here, the flange section of the reinforcement plate has an engagement section to which the end section of the return spring is engaged. The engagement section is located in the vicinity of the through-hole.
According to the present invention, a strength shortage of the base plate caused by weight-lightening of the seat reclining system can be compensated by using the reinforcement plate formed with the flange section and preferably the bead in conformity with a deformation plane, without affecting the weight-lightening of the seat reclining system. Additionally, a part of the reinforcement plate preferably serves as the engagement section for the end section of the return spring, and therefore the number of component parts can be reduced thereby suppressing the production cost of the seat reclining system at the lowest level.
REFERENCES:
patent: 4143905 (1979-03-01), Hensel et al.
patent: 4466661 (1984-08-01), Narita
patent: 4541672 (1985-09-01), Fukuta et al.
patent: 4736986 (1988-04-01), Kato et al.
patent: 5340196 (1994-08-01), Ikegaya et al.
patent: 5749624 (1998-05-01), Yoshida
patent: 5988751 (1999-11-01), Yoshida et al.
patent: 6092874 (2000-07-01), Kojima et al.
Matsumoto Tadashi
Nagasawa Youichi
Foley & Lardner
Fuji Kiko Co. Ltd.
Jr. Milton Nelson
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