Electromagnetic spring-wound clutch

摘要

Input and output member (21), (28) and a clutch disc (32) are coaxially rotatable relative to each other, the clutch disc (32) being frictionally engageable with the input member (21). A coil-wound spring (33) is wound around the input member (21) and connected at its ends to the clutch disc (32) and output member (28). An electromagnetic coil (26) may be energized to attract the clutch disc (32) into frictional engagement with the input member (21), causing the coil-wound spring (33) to tightly wind around the input member (21) and drivably connect the input member (21) to the output member (28). A generally tubular cover (34) surrounds the coil-wound spring (33), the spring means (40) moving the clutch disc (32) toward engagement with the cover (34) when the coil (26) is de-energized. A resilient, non-magnetic spacer (51) is fixed to the clutch disc (32) between the clutch disc (32) and the cover (34) which serves the dual function of absorbing vibration and preventing ohmic engagement of the clutch disc (32) with the cover (34) which would cause leakage of magnetic flux and failure of the coil (26) to engage the clutch (11) when the clutch disc (32) becomes worn.