Patent ID: 8256598
Filing Date: 2012-09-04
Classification: F16D

Abstract:
1. A wrap spring clutch comprising: an input element and an output element positioned adjacent to each other for rotation around a common axis of rotation; a spring surrounding at least respective portions of the input element and the output element and comprising an output end attached to the output element; a permanent magnet positioned adjacent an input end of the spring; a control element attached to the input end of the spring and responsive to a magnetic field generated by the permanent magnet alone without a need for any electrical power to be supplied to the clutch to move from a disengaged position to an engaged position in which the control element frictionally engages the input element so that, upon rotation of the input element about the axis of rotation, the control element causes the spring to wrap down on both the input element and the output element to transmit torque there between; and a coil responsive to a selectively applied electrical current passing there through to selectively redirect the magnetic field generated by the permanent magnet away from the control element; the control element being responsive to the presence of the electrical current in the coil and the redirection of the magnetic field generated by the permanent magnet to move from the engaged position to the disengaged position where it is no longer frictionally engaged with the input element so as to allow the spring to unwrap to terminate the transmittal of torque between the input element and output element.