An inertial lock mechanism for limiting movement of a first object along a constrained path with respect to an adjacent second object. The mechanism includes a lock pin having a flat surface which is pivotally mountable to the first object and is biased toward a position in which the flat surface is parallel to the contrained path. A frame member mountable to the second object engages the flat surface so as to stop relative movement of the pin and rotate the pin against the biasing means at one end of the constrained path. A second stop surface on the frame member is sufficiently spaced apart from the angular surface to permit the biasing means to overcome inertia and pivot the lock pin out of engageable relationship with the second stop surface except when a predetermined amount of relative acceleration of the two objects occurs.

A passenger car seat back inertia latch providing gravity actuated latch release and deceleration responsive inertia latch retention characterized by a compound resolution of predominant opposing gravity and deceleration forces to provide more sensitive and dependable latch retention at a predetermined minimum emergency vehicle deceleration as well as minimum weight to unlock the latch when the vehicle is stationary over a wider range of seat back adjustment and vehicle inclination than is possible with the conventional simple one-piece inertia latch wherein horizontal and vertical coordinates of the center of gravity relative to a latch pivot are solely depended upon to produce respective opposite gravity actuated release and inertia actuated locking moments on the latch element.

The invention consists of an infinitely variable seat reclining mechanism which is composed of a first arm attached to the seat cushion frame and a second arm attached to the seat back frame. A pivot pin rigidly secured to the second arm extends to at least one side thereof on an axis of rotation. The first arm is rotatably mounted on the pivot pin to be capable of relative rotation with respect to the second arm. A pair of locking pawls are rotatably mounted on the first arm. The locking pawls are capable of rotation toward and away from one another about separate pivot points and into contact with a circular friction surface on the second arm. The circular friction surface on the second arm has its center at the axis of rotation between the first and second arms. A spring is included for biasing the locking pawls toward one another. Each of the locking pawls has a substantially V-shaped groove on one end thereof which is capable of engaging the friction surface on the second arm. The friction surface also has a substantially V-shaped section with an included angle equal to the included angle of the grooves in the locking pawls. The interaction between the grooved surfaces on the locking pawls and on the second arm prevent relative rotation between the first and second arms. A lever arm is included for moving the locking pawls away from one another against the spring and out of engagement with the friction surface of the second arm thereby allowing relative rotation between the first and second arms.

A folding backrest in a vehicle, comprises a bearing arm which is assigned to the backrest and is connected to a positionally fixed bearing block in an articulated manner, the bearing arm being assigned a locking element which, when the bearing arm is rotated rapidly about the joint, is guided by the bearing arm along a slotted guide toward a stop or into an end region of the slotted guide, but, upon slow rotation, allows the bearing arm to rotate freely, and the slotted guide has a recess which, when the bearing arm is rotated slowly, allows the locking element to get out of the way of the pivoting region of bearing arm.

A seatback recliner mechanism made up of a fixed frame attachable to a seat bottom and a plate pivoted to the fixed frame and attachable to a seat back. An inertia operated lock mechanism for locking together the pivoted plate and the fixed frame under simultaneous deceleration of both elements. The inertia operated lock mechanism consists of a pawl pivoted on the upper plate and a pendulum pivotably suspended by the upper plate such that the pendulum swings forward under deceleration of the mechanism to abut the pivoted pawl and lock the pawl to the lower fixed frame and thereby lock the seat back and seat bottom.