Hinge mechanism for vehicle seat assembly with a leaf retaining spring

A hinge mechanism for a seat assembly, said seat assembly including a lower seat cushion and a seat back coupled to said seat cushion by said hinge mechanism, said seat back having an upright operative position and being rotatable from said operative position to a forward dump position, said hinge mechanism comprising:

• a seat back arm adapted to be coupled to said seat back;
• a plate member;
• means for securing said plate member to said seat cushion;
• pivot means for rotatably coupling said seat back arm to said plate member for rotation relative to said plate member about an axis perpendicular to said plate member, said arm being rotatable between a first position corresponding to the upright operative position of said seat back and a second position corresponding to the forward dump position of said seat back;
• latch means operative associated with said seat back arm and said plate member for preventing rearward rotation of said seat back arm from said first position and for preventing forward rotation of said seat back arm from said first position when said seat back is experiencing a predetermined deceleration, said latch means permitting forward rotation of said seat back from said first position in the absence of said predetermined deceleration;
• and
• a leaf spring mounted to an edge of said arm with one end extending therefrom and engaging an edge surface of said plate member, said edge surface being arcuate and concentric about said pivot over which said spring end slides as said arm is rotated, said arcuate edge surface terminating in a radially recessed detent portion into which said spring end is seated when the seat back is in said upright operative position whereby a minimum force must be applied to said seat back to remove said spring end from said detent to rotate aid seat back from said upright operative position.