Seat back inertia latch system

Claim 1

A hinge fitting for a vehicle seat having a forward tiltable backrest comprising a first hinge member attachable to a lower seat member, a second hinge member attachable to a backrest seat member and pivotally connected to said first hinge member, an abutment stop for establishing the occupant's seated position of said second hinge member, an inertia latch system including means for arresting forward pivotal movement of said second hinge member under conditions of sudden vehicle deceleration and including automatic means for permitting manual forward tilting of said seat back under a stationary vehicle condition, said system being characterized by a pivoted latch inertia element having an installed center of gravity horizontally displaced from the pivotal center to provide a pivotal moment in one direction toward a latch release orientation and vertically displaced from the pivotal center to provide an inertial pivotal moment in the opposite direction toward latch engagement orientation when the vehicle is subject to sudden deceleration, and inertia latch return linkage means mounted separately from said inertia element responsive to movement of said second hinge member to said stop position to overcome said gravity moment and bias said inertia element in said opposite direction toward an operative latching orientation, including linkage deactivating means responsive to initial forward seat back tilting permitting said gravity moment to move said inertia element to a latch release orientation when said vehicle is stationary.