Patent ID: 8215197

Claim:
A device ( 2 ) for actuating a loose gearwheel ( 4 to 7 ) of a transmission device ( 1 ), the device ( 2 ) comprising: at least one engagement mechanism ( 8 , 9 ) for shifting the gearwheel ( 4 to 7 ) between a state in which the gearwheel ( 4 to 7 ) is engaged with a shaft ( 3 ), and a state in which the gearwheel ( 4 to 7 ) is rotatable with respect to the shaft ( 3 ), the at least one engagement mechanism ( 8 , 9 ) comprising at least one actuator ( 10 , 22 ) arranged at least partially inside the shaft ( 3 ) and actuated by a pressure medium for engaging the gearwheel ( 4 to 7 ) with the shaft ( 3 ), an actuation force from the at least one actuator ( 10 , 22 ) being exerted on the gearwheel ( 4 to 7 ), from inside of the shaft ( 3 ) outwardly, to either engage the gearwheel ( 4 to 7 ) with the shaft ( 3 ) or to disengage the gearwheel ( 4 to 7 ) from the shaft ( 3 ), the at least one actuator ( 10 , 22 ) being a piston-cylinder unit accommodated inside the shaft ( 3 ) and rotationally fixed within the shaft ( 3 ); and a pump, which pressurizes the pressure medium, being arranged inside the shaft.