Self-adjusting clutch or brake

Claim 1

A friction-type torque-producing coupling having, in combination, axially fixed and axially movable relatively rotatable first and second rings of magnetic material adapted to be drawn into axial gripping engagement by magnetic flux threading a toroidal path through the rings, an axially fixed support member disposed adjacent said second ring on the side thereof opposite the first ring and having a plurality of holes therein angularly spaced around and paralleling the coupling axis, pins rigid with said second ring and projecting slidably into the respective holes, stop members disposed intermediate the ends of said holes and frictionally gripping and slidable axially relative to a peripheral surface on one of said members, pairs of opposed abutments disposed on opposite sides of each of said stop members, one being engageable with the stop member upon axial engagement of said rings to shift the stop member along said axis by an amount equal to the wear that has occurred at said ring faces, the other abutments engaging the stop member to limit the extent of separation of the rings when the latter are deenergized whereby to establish an air gap of constant width each time the rings are deenergized, and means supporting said second ring from said support member and transmitting the coupling torque comprising a plurality of leaf springs between said support member and second ring angularly spaced around and extending along secants of the ring, and means securing opposite ends of said springs to said support member and said second ring respectively whereby such ring is supported for free axial floating and for transmitting torque between said rings, said springs being stressed to flex laterally and bias said second ring away from the first ring with a force which is less than the frictional resistance holding the axial positions of said stop members.