Shift lock system for an automatic transmission of a motor vehicle

A shift lock system for an automatic transmission of a motor vehicle having a shift lever operative for selecting operating ranges of the transmission including at least a parking range and a drive range, a panel having an opening at least with a parking notch corresponding to the parking range and a driven notch corresponding to the drive range, a pin selectively engaged with one of the notches, a push button provided on the shift lever and operatively connected to the pin to push the pin to a downward position for removing the pin from the parking notch, and a brake switch to be closed at a condition of depression of a brake pedal of the vehicle, the system comprising:

• lock means, pivotally swingable to a release position by the pin when the pin moves the drive notch to the downward position inn accordance with operative of the shift lever, for restricting movement of the pin at the parking notch to prevent the pin from being moved from the parking notch;
• solenoid means responsive to a closed condition of the brake switch for moving the lock means to the release position inn order to enable the pin to release from the parking notch;
• a shift lock detecting switch operatively connected to the lock means to be opened when the lock means moves to the release position;
• a parking range position switch to be closed when the shift lever is positioned in the parking range;
• control means connected to the shift lock detecting switch and the parking range position switch in series for producing a first signal when either of said switches is opened and a second signal when both of said switches are closed, respectively;
• and
• interlocking means for interlocking an ignition key to prevent the ignition key from turning in response to said first signal and for releasing the ignition key to enable the ignition key to turn in response to the second signal, respectively.