Patent ID: 6848559

Claim:
A shift locking apparatus for an automatic transmission, the shift locking apparatus comprising: a lock cam for connecting, along its circumference, to a shift lock cable on one part, to a key lock cable on another part, and having a third part provided with a latching step; a latching means allowed to move forward or backward by a contact force of a brake pedal or by an elastic force of at least one spring thereby engaging the latching step of the lock cam and causing the lock cam to be in a latched or unlatched state depending on an engaged or disengaged state of the brake pedal and on a pivotal movement of the lock cam wherein the latching means further comprises; a stopper pin for placing into a reverse or backward position under contact force from the brake pedal when the brake pedal is disengaged, but into a progressive or forward position under elastic force from a first spring when the brake pedal is engaged; a cylinder for housing a piston integrally connected with the stopper pin; a second spring which has a spring constant larger than that of the first spring, the second spring being disposed between a free end of the piston and a closed end of the cylinder opposite to the free end of the piston, whereby the cylinder is provided with elastic force of the second spring toward the cam when the brake pedal is disengaged but moves together with the stopper pin when the brake pedal is engaged; a casing housing the lock cam and the latching means therein, for constraining the lock cam within a pivotal angle of the latched state or unlatched state and restraining the latching means to be in a retracted or extended state; and a shift lock pin, allowed to move forward or backward by a contact force of a shift lever or by an elastic force of at least one spring, for cooperating with the lock cam via the shift lock cable to lock or release the shift lever in a parking position.