Chairs and seats – Movable back – Tiltable
Reexamination Certificate
1999-12-20
2001-10-23
Nelson, Jr., Milton (Department: 3624)
Chairs and seats
Movable back
Tiltable
Reexamination Certificate
active
06305748
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to seat recliners for a vehicle, and more specifically to seat recliners using a so-called taumel gearing that employs intermeshing spur and ring gear elements.
One example of such recliners includes two relatively moveable brackets connected with a seat cushion and a seat back, respectively. The brackets are connected with each other in an eccentric relation through a shaft. The shaft is supported at its one end by a base or cover member that is fixed to one of the brackets. The brackets have intermeshable internal and external teeth, respectively. A pair of wedges are disposed on the shaft in a circumferentially spaced relation to each other. A spring biases the wedges so as to be apart from each other and moved toward a radial projection that is disposed on the shaft. The wedges and the spring cooperate to eliminate a radial play or clearance between the internal and external teeth of the brackets at the intermeshing position to thus surely retain one of the brackets at a desired position relative to the other bracket.
In such conventional recliners, it is likely that the wedges are undesirably displaced from the axial position on the shaft upon rotation of the shaft. This is because an axial space for accommodating the spring is produced between the wedges and the base member becomes too large so that there is no support for the wedges in an axial direction of the shaft.
In order to restrict the undesired displacement of the wedges, there has been proposed an arrangement in which the spring includes a portion extending along an axial end face of each wedge. This arrangement, however, will perform insufficient retention of the wedges in the axial position because of the spring being made of a wire material. Further, since a non-uniform axial space between the wedges and the base member tends to be produced, it will occur that the spring remains pressed against the wedges and locked up thereon in a case where the axial space is partly smaller than a diameter of the spring. This will cause influence on the movement of the wedges upon rotation of the shaft, leading to insufficient performance of the wedges in elimination of the play between the intermeshing teeth of the brackets.
Otherwise, it will be proposed that a retainer for the wedges is provided as a separate part. In such a case, the total number of parts of the seat recliner will be increased and then the manufacturing cost will be raised.
An object of the present invention is to provide an improved seat recliner for a vehicle which has a simple structure and is capable of holding the wedges in a proper position where the wedges can surely operate during rotation of the shaft in operation of the seat recliner.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a seat recliner comprising:
a base;
a first bracket fixed to said base, said first bracket defining internal teeth;
a camshaft rotatably supported by said base and said first bracket, said camshaft having a first axis and a radially projecting cam portion;
a second bracket moveable relative to said first bracket, said second bracket being disposed between said base and said first bracket, said second bracket defining external teeth meshable with the internal teeth and an opening receiving said cam portion;
a positioning member cooperating with said cam portion to define a rotatable body fitted to the opening of said second bracket and bring a center axis of the rotatable body into a position eccentric to said first axis, said rotatable body causing displacement of intermeshing between the external teeth and the internal teeth upon rotation of said camshaft;
two wedges disposed on said cam portion within the opening of said second bracket, said two wedges being adjacent to said positioning member in an axial direction of said camshaft and spaced from each other in a circumferential direction of said camshaft;
a spring biasing said two wedges in opposed circumferential directions of said camshaft, said spring cooperating with said wedges to reduce a clearance between the external teeth and the internal teeth upon intermeshing;
a bushing fixed to said base, said bushing supporting said camshaft; and
a support holding said two wedges in a proper position relative to said cam portion of said camshaft, said support being disposed on said bushing and extending in a direction of said axis.
REFERENCES:
patent: 4371207 (1983-02-01), Wilking et al.
patent: 5154475 (1992-10-01), Kafitz
patent: 5308294 (1994-05-01), Witting et al.
patent: 5312158 (1994-05-01), Witting et al.
patent: 5586833 (1996-12-01), Vossmann et al.
patent: 5634380 (1997-06-01), Scholz et al.
patent: 5871414 (1999-02-01), Voss et al.
patent: 3-237904 (1991-10-01), None
patent: 4-269912 (1992-09-01), None
Foley & Lardner
Fuji Kiko Co. Ltd.
Jr. Milton Nelson
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