Sensor for a seat belt retractor

The seat belt retractor has a spool rotatably mounted to a frame and a spool locking device for locking the spool against rotation, including an actuator for actuating the locking device comprising a support carrying a mass (280) and a pawl. The mass moves from an initial position to an actuating position to actuate the pawl into engagement with the ratchet (190) on the spool. The actuator comprises an adjustment mechanism (380) for adjusting the distance between the pawl and the ratchet. A vehicle seat belt retractor comprises a frame, a spool rotatably mounted to the frame and a spool locking device for locking the spool against rotation. The spool locking device includes actuating means for actuating the locking device. The actuating means comprises a support carrying a mass (280) and a pawl, the mass being arranged to move from an initial position to an actuating position to actuate the pawl into engagement with the ratchet (190) on the spool. The actuating means comprises an adjustment mechanism (380) for adjusting the distance between the pawl and the ratchet. The adjustment mechanism may comprise means for adjusting the support (290) relative to a housing (390), means for adjusting the tip of the pawl relative to the pawl body or a deformable pawl tip.