| 摘要 |
An overspeed safety device for a pneumatic rotation motor having a stator ( 10 ) with an air inlet passage ( 16 ), a rotor ( 12 ), and a speed governor for determining a maximum speed level, and comprising a speed responsive actuator ( 34 ) connected to the rotor ( 12 ) and a valve ( 33 ) shiftable by the actuator ( 34 ) from a normally open position to a closed position so as to block or substantially restrict the air flow through the inlet passage ( 16 ) at the attainment of motor speed levels exceeding a predetermined maximum level should the speed governor malfunction, wherein the actuator ( 34 ) comprises a spring biassed contact element ( 48 ) connected to the rotor ( 12 ) and responsive to centrifugal action, and the valve ( 33 ) comprises a disc-shaped valve element ( 36 ) pivotally supported in the inlet passage ( 16 ) and maintained in its open position by one magnet ( 42 ) and in its closed position by another magnet ( 43 ).
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