Adjusting mechanism for a vehicle seat back

Claim 1

An adjustment mechanism for an adjustable seat back of a vehicle seat structure, comprising: a rotary shaft adapted to be connected to an adjustable seat back for rotation during adjustment of said seat back; and a brake mechanism for selectively inhibiting and permitting rotation of said shaft to correspondingly inhibit and permit adjustment of said seat back, said brake mechanism including: a plurality of circumferentially spaced wedge structures positioned around said shaft, each wedge structure including a pair of circumferentially spaced wedge surfaces spaced radially outwardly from said shaft, a plurality of circumferentially spaced clamping structures arranged in a space formed between said shaft and respective ones of said wedge structures, each clamping structure including: a pair of clamping bodies located in said space adjacent respective ones of said wedge surfaces, and an elastic member disposed circumferentially between said pair of clamping bodies for biasing said pair of clamping bodies toward their respective wedge surfaces to be urged into clamping engagement with said shaft for braking said shaft against rotation in both direction of rotations and thereby prevent adjustment of said seat back; and an actuating mechanism for displacing said clamping bodies toward their respective elastic members and out of said clamping engagement with said shaft, said actuating mechanism including: a plurality of claws each disposed circumferentially between two of said clamping structures, each claw including first and second parts movable circumferentially relative to one another, said first claw part arranged to bear against a clamping body of one of said two clamping structures, and said second claw part arranged to bear against a clamping body of the other of said two clamping structures; first and second slotted members, said first slotted member fixed to said first claw parts, said second slotted member fixed to said second claw parts, said first and second slotted members arranged to rotate about a common axis of rotation coinciding with a longitudinal axis of said shaft, each of said slotted members including a slot, said slots being superimposed over one another in overlapping relationship and arranged at an oblique angle to one another; and a pin extending through both of said first and second slots, said pin being movable within said slots in a first direction for rotating said first and second slotted members opposite one another to displace said claw parts toward respective clamping bodies and thereby push said clamping bodies into non-clamping relationship with said shaft, and in a second direction for rotating said first and second slotted members opposite one another to displace said claw parts away from said respective clamping bodies to enable said elastic members to push said clamping bodies into clamping relationship with said shaft.