Emergency locking retractor for seat belt assemblies

An emergency locking retractor for a seat belt assembly comprising, in combination, a frame, a reel rotatably supported by said frame and having a belt thereon, first resilient means urging to said reel to rotate in a direction of belt retraction, toothed wheel means rotatable with said reel, said toothed wheel means having teeth or protuberances on and along its periphery at a predetermined pitch, a locking pawl pivotally mounted on said frame for movement into and out of engagement with said teeth or protuberances of said toothed wheel means, said locking pawl being effective to lock said reel against rotation in a direction of belt extension upon engagement with said toothed wheel means, inertia wheel means having protuberanes on and along its periphery at the same pitch as said predetermined pitch and disposed in coaxial relationship to said toothed wheel means so as to be rotatable through a predetermined angle relative to the same, second resilient means for normally holding said inertia wheel means in a predetermined angular position relative to said toothed wheel means, where said protuberances of said toothed wheel means and of said inertia wheel means are at the same phase, and for permitting said inertia wheel means to rotate in synchronism with said toothed wheel means during normal rotation of said reel in the direction of belt extension at relatively low acceleration, said second resilient means yielding upon a high acceleration in exccess of a predetermined value being imparted to said reel in the direction of belt extension to permit angular displacement of said inertia wheel means through said predetermined angle relative to said toothed wheel means so as to cause a difference in phase of said protuberances between the toothed wheel means and the inertia wheel means, as well as a change in combined peripheral contour formed by the protuberances of the toothed wheel means and the inertia wheel means, a pivotally supported follower lever following the combined peripheral contour formed by said protuberances, third resilient means urging said follower lever toward the peripheral contour whereby said follower lever is normally held in sliding contact with at least said toothed wheel means and oscillates in conformity with the combined peripheral contour, and means associating said follower lever with said locking pawl in a manner such that the locking pawl permits unobstructed passage therepast of said teeth or protuberances on said toothed wheel means during said normal rotation of the reel and, upon occurence of said change in combined peripheral contour, is held pivoted toward said toothed wheel means for engagement therewith.