Seatbelt retractor having an inertial sensor weight with a guide surface

A seatbelt retractor assembly comprising:

• a seatbelt retractor;
• an actuator for locking and unlocking said seatbelt retractor;
• an inertial sensor mass for detecting changes in vehicle acceleration, said inertial sensor mass having a guide surface for interacting with an actuator surface to move said actuator;
• said guide surface movable between an unlocking position wherein said actuator unlocks said seatbelt retractor and a locking position wherein said actuator locks said seatbelt retractor;
• and
• said guide surface comprising an inner profile portion and an outer profile portion, said actuator surface in contact with said inner profile portion in said unlocking position and continuing in contact with said outer profile portion as said actuator moves toward said locking position, said outer profile portion causing a deceleration, thereby slowing said actuator prior to said locking position.

A method of controlling a locking pawl mechanism for a seatbelt retractor, comprising the steps of:

• (a) linking movement of an inertial sensor mass to movement of an actuator for a seatbelt retractor, the actuator having an unlocked position unlocking the seatbelt retractor and a locked position locking the seatbelt retractor;
• (b) accelerating the actuator from the unlocked position to the locked position at an initial rate;
• and
• (c) accelerating the actuator at a progressively increasing first intermediate rate following the initial rate, the first intermediate rate different than the first rate.