Patent ID: 7191886
Filing Date: 2007-03-20
Classification: F16D

Abstract:
1. An actuating drive for transmitting drive torque to a power takeoff, said actuating drive comprising: a drive unit; a braking device comprising a cylindrical surface; and a wrap spring comprising a plurality of turns which are concentric to said cylindrical surface, a pair of ends, a first actuating area on each of said ends, and a second actuating area on each of said ends, wherein, when said drive unit exerts a first drive torque in a first direction, the first actuating area of one of said ends is nonrotatably connected to said drive unit, the turns undergo a diameter change away from the cylindrical surface, and the second actuating area of the one of said ends is nonrotatably connected to the power takeoff for transmitting drive torque, wherein, when said first drive torque from said drive unit is interrupted, the turns undergo a diameter change toward the cylindrical surface and frictionally engage the cylindrical surface to block transmission of restoring torque from the power takeoff to said drive unit, and wherein, when said drive unit exerts a second drive torque in a second direction which is opposite to the first direction, the first actuating area of the other of said ends being nonrotatably connected to said drive unit so that said second drive torque and said restoring torque acting in the same direction so that torque is exerted on both ends of said wrap spring simultaneously.