Actuating device for an internal expanding brake with a manually actuable restoring device

Actuating device for an internal expanding brake comprising

• a housing,
• at least one expansion piston displaceably mounted in the housing, in which an adjusting pin is displaceably arranged, on which a brake shoe is supported,
• an adjusting device for automatic adjustment of the adjusting pin depending upon the clearance between the brake shoe and a brake drum of the internal expanding brake, wherein the adjusting device comprises an adjusting nut which is rotatably mounted in or on the expansion piston and cooperates with a thread of the adjusting pin, in order by rotation of the adjusting nut to displace the adjusting pin relative to the expansion piston,
• a restoring device for manual setting and restoration of the adjusting pin relative to the expansion piston, the restoring device having an actuating pin which is rotatably mounted in the housing and is configured for transmitting a torque applied manually to the actuating and a restoring gear mechanism which has a first gearwheel coupled to the actuating pin and a second gearwheel coupled to the adjusting nut in order to transmit the rotary movement of the actuating pin to the adjusting nut, wherein the first gearwheel of the restoring gear mechanism, said gearwheel being coupled to the actuating pin, is displaceable in the axial direction of the actuating pin and is bringable by means of a coupling device, depending upon the torque transmitted, into and out of non-rotational engagement with the actuating pin.