Patent ID: 6675940
Filing Date: 2004-01-13
Classification: B60T,F16D,H02K

Abstract:
A power-off brake with an override release mechanism comprising:a friction disk attachable to an elongated drive shaft for rotating about an axis, the friction disk having a first surface and a second surface substantially perpendicular to the axis; a clapper adjacent to the second surface of the friction disk; a field assembly having a first side positioned adjacent to the clapper to pull the clapper away from the friction disk when current is passed therethrough such that the friction disk is free to rotate; a first bias element for generating a first bias force between the clapper and the field assembly to push the clapper against the friction disk when no current is passed through the field assembly such that the friction disk is not free to rotate; a reaction plate assembly including a reaction plate having a first side adjacent to a second side of the field assembly, and a second side with at least one feature, and a second bias element between the reaction plate and the field assembly for generating a second bias force between the reaction plate and the field assembly; and a release plate adjacent to the second side of the reaction plate, the release plate being coupled to the clapper to selectively facilitate release of the friction disk when no current flows through the field assembly, the release plate having at least one actuator for selectively engaging the at least one feature of the reaction plate, wherein when the release plate is rotated, the at least one actuator cams against the at least one feature thereby moving the reaction plate towards the clapper which compresses the second bias element, as the second bias element compresses the second bias force increases such that as the second bias force becomes greater than the first bias force, the first bias element compresses and thereby the clapper moves away from the friction disk to allow rotation thereof.