Seat belt retractor with deformable emergency lock mechanism

Claim 1

A seat belt retractor for a seat belt comprising: a reel shaft for winding the seat belt therearound, a frame for rotationally supporting the reel shaft, a return spring situated between the reel shaft and the frame for winding the seal belt on the reel shaft, first emergency lock means for locking the reel shaft upon detection of a predetermined acceleration, second emergency lock means for locking the seat belt drawn out from the reel shaft upon detection of the predetermined acceleration, said second emergency lock means including a slider provided on the frame to slide parallel to movement of the seat belt in the frame when withdrawing from the reel shaft; a rotatable member having one end pivotally attached to the frame; a pusher connected to the other end of the rotatable member, said pusher facing the slider to have the seat belt between the pusher and the slider; a deformable portion without elasticity situated between the pusher and the rotatable member so that when the seat belt is withdrawn with less than a predetermined force, the seat belt is engaged between the pusher and the slider and is held therebetween without deformation of the deformable portion, and when the seat belt is withdrawn with more than the predetermined force, while the seat belt is held between the pusher and the slider, the deformable portion is deformed to prevent the holding force on the seat belt between the pusher and the slider from exceeding a predetermined holding force, and the seat belt together with the pusher and the slider are further withdrawn in a direction away from the seat belt retractor to thereby prevent breaking of the seat belt while reducing withdrawing force on the seat belt; and a stopper formed on the frame for stopping movement of the slider, said stopper deforming and permitting the slider to slide further out of the frame when force above the predetermined force is applied to the stopper, and lock actuate means including an acceleration sensor, said lock actuate means actuating said first and second lock means.