Patent ID: 7650978

Claim:
An actuating device ( 1 ) for operating a parking-lock mechanism of a drive train of a vehicle having an automatic transmission, the parking-lock mechanism comprising: at least one piston unit ( 4 ), which is arranged in a housing ( 3 ) and is axially displaceable in an opening direction to disengage the parking-lock mechanism and in a closing direction to engage the parking-lock mechanism; a spring mechanism ( 2 ) biases the piston unit ( 4 ) which biases the parking-lock mechanism to a closed state against a pressurized fluid, which biases the piston unit ( 4 ) in and open direction; a detent element ( 5 ), when an axial position of the piston unit ( 4 ) is equivalent to an open state of the parking-lock mechanism, is automatically activated to retain the piston unit ( 4 ) in the axial position equivalent to the open state of the parking-lock mechanism; an electromagnetic operating device ( 6 ) for operating a release element ( 7 ), which deactivates the detent element ( 5 ), wherein the detent element ( 5 ), the piston unit ( 4 ), and the release element ( 7 ) interact such that when the detent element ( 5 ) is deactivated, the parking-lock mechanism remains open and the electromagnetic operating device ( 6 ) is without electric current, and a fluid pressure is applied to the piston unit ( 4 ) to provide a force component to bias the piston unit ( 4 ) which biases the parking-lock mechanism in the opening direction, the force component being smaller than a release force of the parking-lock mechanism; and an emergency unlocking mechanism functionally connected to the piston unit ( 4 ) and which biases the piston unit ( 4 ) into the axial position equivalent to the open state of the parking-lock mechanism, the emergency unlocking mechanism ( 14 ) including a first manually actuated lever-arm ( 22 ) or manually displacing the piston unit ( 4 ) from its axial position equivalent to a closed state of the locking mechanism, whereby the parking-lock mechanism is disengaged, and an emergency locking mechanism ( 15 ) including a manually actuated second lever-arm ( 24 ) for deactivating the detent element ( 5 ) whereby the piston unit ( 4 ) is brought into its axial position equivalent to the closed state of the locking mechanism, whereby the parking-lock mechanism is engaged.