Web-sensitive retractor lock-out mechanism

Abstract

A passive seat belt system is provided with a door mounted retractor operable by a remotely located inertia sensing device on the vehicle chassis. The door mounted retractor has an electrically operated means to lock the retractor reel against turning when operated by the inertia sensing device. The retractor is also provided with a mechanically operated web sensitive device to lock the reel against belt pay out at high reel angular accelerations. The web sensitive device includes an inertia wheel secured on the portion of reel shaft and mounted on the shaft so as to be rotatable with respect thereto. A coiled spring concentric with the shaft has its first end fixed to the shaft and its second end fixed to the inertia wheel so as to prevent relative rotation between the inertia wheel and the shaft. An annulus is mounted on the shaft so as to permit rotation of the shaft with respect thereto. The annulus has side walls overlying the coiled spring, and an arm is integral with the annulus for engaging the locking bar. Engagement of the arm with the locking bar occurs when the rate of angular velocity of the reel due to safety belt protraction increases at a rate at which the coiled spring can no longer exert a force to overcome the angular momentum of the inertia wheel. In consequence, the coiled spring radially expands and engages the side walls of the annulus to cause the annulus to rotate in unison with the shaft. Thus the arm on the annulus is rotated into engagement with the lock bar to move the lock bar into engagement with the teeth of the ratchet wheels.