Actuating drive with a wrap spring arrangement

US7191886B2 · kind B2 · utility

Assignee

• ZF FRIEDRICHSHAFEN AG · DE

Inventors

• Martin Flückiger · Schweinfurt, DE
• Thomas Walter · Kolitzheim, DE
• Matthias Mülier · Schweinfurt, DE
• Peter Fenn · Waigolshausen, DE

Key dates

• Filing date: Nov 29, 2004
• Grant date: Mar 20, 2007
• Expiry date: Mar 19, 2025

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16D67/00
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

An actuating drive for transmitting drive torque to a power takeoff, comprising a drive unit; a braking device comprising a cylindrical surface; and a wrap spring having a plurality of turns which are concentric to the cylindrical surface, a pair of ends, a first actuating area on one of the ends, and a second actuating area on one of the ends. When the drive unit exerts a drive torque in a first direction, the first actuating area is nonrotatably connected to the drive unit, the turns undergo a diameter change away from the cylindrical surface, and the second actuating area is nonrotatably connected to the power takeoff for transmitting drive torque. When the drive torque 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 the drive unit.