Patent ID: 6047805
Filing Date: 2000-04-11
Classification: F16D

Abstract:
An electric clutch and brake comprising:a helical spring coaxial with an axis of rotation and having a first end and a second end;a first machine element rotatable about the axis of rotation and attached to the first end of the helical spring, the first machine element having a first frictional surface disposed on a first radial side of the helical spring;a second machine element rotatable about the axis of rotation and having a second frictional surface disposed on the first radial side of the helical spring, the second machine element further having a pole face adjacent to the second end of the helical spring;an electromagnetic coil adjacent to the pole face so as to pull the second end of the helical spring into contact with the pole face when electrical current is passed through the electromagnetic coil; anda fixed retention plate having a third frictional surface disposed on a second radial side of the helical spring opposite to the first radial side of the helical spring, wherein the helical spring is sized and positioned, when no current flows through the electromagnetic coil, to cause the helical spring to relax causing a frictional linking between the third frictional surface and the first machine element to brake the first machine element and, when current flows through the electromagnetic coil, to cause the helical spring to wrap down causing a frictional linking to serve as a clutch between the first frictional surface and the second frictional surface.