Seat belt retractor with improved web sensor

摘要

A seat belt retractor (20) has a spool (100) and a web sensor (200) configured to activate at a desired rotational acceleration of the spool (100). The web sensor (200) includes an inertia wheel (202) rotatable relative to the spool. A sensor (210) has one or more lock teeth (220, 222) thereon. The web sensor pawl (210) is rotationally supported relative to the spool (100). The web sensor (210) includes a torsion spring (204) having a center coiled portion (205) and first and second spring leg (206a, 206b). The inertia wheel (202) includes a plurality of pins (308a - e), the placement of each pin configured to correspond to a set level of rotational acceleration. The center coiled portion (205) of the torsion spring (204) is centrally disposed on the inertia wheel (202). The first spring leg (206a) secured to the spool (100) or pilot wheel. The second spring leg (206b) secured to a one of the pins. The inertia wheel (202) is configured to cause a relative rotation relative to the spool (100) as the spool is rapidly moved. The relative rotation causes the movement of the web sensor (210) from a rest position to an activated position.