Chairs and seats – Movable back – Tiltable
Reexamination Certificate
1999-06-21
2001-11-20
Barfield, Anthony D. (Department: 3624)
Chairs and seats
Movable back
Tiltable
C297S366000
Reexamination Certificate
active
06318805
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a reclining mechanism for a vehicle seat for adjusting an inclined angle of a back rest of the seat relative to a seat cushion.
2. Description of the Prior Art
Disclosed in Japanese Patent Laid-open Publication No. 8-52040 is a reclining mechanism for a vehicle seat which is composed of a pair of arm members for attachment to a frame structure of a seat cushion and to a frame structure of a back rest, the arm members being connected by means of a hinge pin for relative rotation about the hinge pin, a slide pawl slidably coupled with one the arm members to be moved in a radial direction with respect to the hinge pin for engagement with a ratchet portion of the other of the arm members and for disengagement from the ratchet portion, and a cam element mounted on the hinge pin for rotation therewith and engaged with the slide pawl for maintaining the slide pawl in engagement with the ratchet portion of the arm member and for disengaging the slide pawl from the ratchet portion when it is rotated with the hinge pin. In the reclining mechanism, the relative rotation of the arm members is restricted by engagement of the slide pawl with the ratchet portion to lock the back rest at an inclined angle and is permitted by disengagement of the slide pawl from the ratchet portion for adjustment of the inclined angle of the back rest.
In the reclining mechanism, the engagement of the slide pawl with the ratchet portion of the arm member is maintained in a condition where the slide pawl is pressed by engagement with a portion of the cam element. When the cam element is rotated with the hinge pin to disengage the slide pawl from the ratchet portion of the arm member, the slide pawl is retracted by engagement with a portion of the cam element. If the reclining mechanism is applied with a heavy load, the slide pawl is slightly rotated due to an error in assembly of the component parts of the reclining mechanism. This results in looseness in engagement of the slide pawl with the ratchet portion of the arm member.
SUMMARY OF THE INVENTION
It is, therefore, a primary object of the present invention to provide a reclining mechanism for a vehicle seat wherein rotation of the slide pawl is prevented to firmly maintain the engagement of the slide pawl with the ratchet portion even if the reclining mechanism is applied with a heavy load.
According to the present invention, the object is accomplished by providing a reclining mechanism for a vehicle seat, which comprises a first arm member for attachment to a frame structure of a seat cushion or a back rest of the vehicle seat, a second arm member for attachment to a frame structure of the other of the back rest or the seat cushion, the second arm member being connected with the first arm member by means of a hinge pin for relative rotation about the hinge pin and having a circular ratchet portion concentric with the hinge pin, a pair of slide pawls slidably coupled with the first arm member in a radial direction with respect to the hinge pin to be moved toward and away from the ratchet portion of the second arm member, the slide pawls each being formed at their outer ends with a semi-circular toothed portion for engagement with the ratchet portion of the second arm member and at their inner ends with a pair of spaced legs, a cam element mounted on the hinge pin for rotation therewith and disposed between the inner ends of the slide pawls, the cam element having a pair of radial projections opposed to the spaced legs of the slide pawls, and a pair of spaced rollers disposed between the radial projections of the cam element and the spaced legs of the slide pawls to maintain the slide pawls in engagement with the ratchet portion of the second arm when retained in engagement with the spaced legs of the slide pawls under load of a torsion spring applied to the cam element and to permit disengagement of the slide pawls from the ratchet portion of the second arm member when released from the spaced legs of the slide pawls by rotation of the cam element against the load of the torsion spring.
In a practical embodiment of the present invention, it is preferable that a cam plate is mounted on the hinge pin for rotation therewith to disengage the slide pawls from the ratchet portion of the second arm member by engagement therewith when the cam element is rotated against the load of the torsion spring applied thereto to release the rollers from the spaced legs of the slide pawls.
REFERENCES:
patent: 5590931 (1997-01-01), Fourrey et al.
patent: 5622407 (1997-04-01), Yamada et al.
patent: 5632525 (1997-05-01), Uramichi
patent: 5762400 (1998-06-01), Okazaki et al.
patent: 5788325 (2000-08-01), Ganot
patent: 5881854 (1999-03-01), Rougnon-Glasson
patent: 6102480 (2000-08-01), Asano
patent: 198 14 225 A 1 (1998-03-01), None
patent: 56-52010 (1981-05-01), None
patent: 7-136032 (1995-05-01), None
patent: 8-52040 (1996-02-01), None
Araco Kabushiki Kaisha
Barfield Anthony D.
Reed Smith Hazel & Thomas LLP
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