Inertia latch assembly for seat hinge mechanism

In a seat hinge mechanism having a lower hinge member connected to a seat bottom and an upper hinge member connected to a seatback and rotatable with respect to said lower hinge member about a pivot, and an inertia sensing latch assembly for allowing rotation of said seatback relative to said seat bottom under normal use conditions and preventing such rotation when predetermined deceleration forces are present, said inertia sensing latch assembly comprising:

• stop means operatively associated with said lower hinge member for defining first and second stop surfaces, wherein said first stop surface limits rotation of said upper hinge member in one direction;
• an inertial actuator rotatable with respect to said upper hinge member and including means for engaging said second stop surface when said upper hinge member rotates in an opposite direction due to said predetermined deceleration forces, and an actuator projection offset from a center of rotation, wherein said inertial actuator has a center of gravity above and horizontally spaced from the center of rotation;
• release lever means pivotally connected by a pivot pin to said upper hinge member for engaging said actuator projection to rotate said inertial actuator into a normal position against said stop means when said upper hinge member is fully rotated against said first stop surface, said release lever means having a first bore spaced from said pivot pin which receives a first pin connected to said upper hinge member such that said release lever means is rotatable about said first pin between first and second positions, said release lever means includes cam means for receiving a second pin connected to said upper hinge member with said cam means having first and second edges defining said first and second positions;
• and
• biasing means acting on said release lever means for biasing said release lever means to release said actuator projection when said upper hinge member is rotated in said opposite direction and to allow said inertial actuator to rotate in one direction by gravity if said predetermined deceleration forces are not present.

In an inertia-sensitive seat hinge mechanism operable for allowing rotation of a seatback relative to a seat bottom under normal use conditions and preventing such relative rotation therebetween when predetermined deceleration forces are present, said inertia-sensitive seat hinge mechanism including a lower hinge member connected to said seat bottom and an upper hinge member connected to said seatback and rotatable with respect to said lower hinge member about a pivot, and an inertia sensing latch assembly, said inertia sensing latch assembly comprising:

• stop means associated with said lower hinge member for defining first and second stop surfaces, wherein said first stop surface limits rotation of said upper hinge member in one direction;
• an inertial actuator rotatable with respect to said upper hinge member and including means for engaging said second stop surface when said upper hinge member rotates in an opposite direction due to said predetermined deceleration forces, and an actuator projection offset from a center of rotation, wherein said inertial actuator has a center of gravity above and horizontally spaced of said center of rotation;
• release lever means for engaging said actuator projection to rotate said inertial actuator into a normal position against said stop means, said release lever means being pivotally mounted about a pivot pin to said upper hinge member and having a bore spaced from said pivot pin which receives a first pin extending from said upper hinge member and said release lever means including a first edge surface defining a recess in which said projection is retained to rotate said inertial actuator into said normal position when said upper hinge member is rotated fully in said one direction against said first stop surface;
• and
• biasing means interconnecting said release lever means to said upper hinge member for biasing said release lever means to release said actuator projection when said upper hinge member is rotated in said opposite direction and to allow said inertial actuator to rotate by gravity if said predetermined deceleration forces are not present.