Patent ID: 7464892

Claim:
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 resting on a sensor housing, said inertial sensor mass having a wide portion above a narrow portion, the narrow portion having a bottom with a pivot point of the sensor mass relative to the housing which establishes the sensor mass tilt angle θ, the wide portion having a guide surface for interacting with an actuator surface of said actuator to move said actuator; said guide surface being horizontally and vertically movable between an unlocking position wherein said actuator unlocks said seatbelt retractor and a locking position wherein said actuator locks said seatbelt retractor as the inertial sensor tilts about the pivot point; and wherein said guide surface has an inner profile portion in contact with said actuator in said unlocking position, the inner profile having a surface curvature, and said guide surface having an outer profile portion, said actuator continuing in contact with said outer profile portion as said actuator moves toward said locking position, said outer profile portion curving in an opposite direction from said inner profile portion causing a deceleration, thereby slowing said actuator prior to reaching said locking position.