US Patent 7168742 Seatbelt device

A seat belt device includes a lap anchor and connector assembly that are engaged by a latch pressed by a first latch spring. In the event that inertia force is applied to the connector assembly in a direction that tends to urge the disengagement of the connector assembly and the lap anchor, the latch tries to move in the direction of disengagement. The attempted movement causes retaining shoulder portions of the latch to abut against latch holding portions of a second latch spring, thereby preventing movement of the latch in the direction of disengagement. Thus, engagement of the connector assembly and the lap anchor is stable, and disengagement of the connector assembly and the lap anchor is prevented.