Inertia seat back lock

摘要

An inertia seat back lock includes a frame secured to the seat cushion member and having side walls pivotally supporting the shaft portion of a reel. A coil spring secured to the shaft portion and an abutment of one side wall biases the reel in a winding direction. A strap secured to the reel and to the pivoted seat back member normally permits free pivoting movement of the back member relative to the cushion member as the reel unwinds and winds. An inertia responsive member pivoted to the frame includes a pawl portion traversing toothed end plates of the reel and a pair of extensions overlying the shaft portion and located between the end plates and the frame side walls. The center of gravity of the inertia member normally locates the pawl portion out of the path of the end plates. When a predetermined deceleration level is exceeded, the inertia member pivots relative to the frame and the pawl portion engages one tooth of each of the end plates to block forward tilting movement of the back member relative to the cushion member. The flexible strap takes up a portion of the shock loads. The spring is initially preloaded and hooked to the reel. When the reel is assembled to the frame and the strap is initially unwound, the outer end of the spring is transferred to the abutment of the frame side wall.