| 摘要 |
A clutch apparatus 8 comprises a torque limiter body 12 and a solenoid brake magnet 14. The torque limiter body 12 is pivotable relative to the solenoid brake magnet 14 when torque acting between the torque limiter body 12 and the solenoid brake magnet 14 is greater than a threshold value and is not pivotable relative to the solenoid brake magnet when the torque is less than the threshold value, preferably due to friction of thrust washer 42, which may contain PTFE. Energisation of coil assembly 20 enables the torque limiter body 12 to pivot relative to the solenoid brake magnet 14, overriding the torque limiting clutch. The threshold is preferably adjustable by nut 24 altering the force of biasing means 46. The clutch 8 preferably is used as a locking device for an arm (2, fig 1) holding a machine keyboard close to an operator. |
