| 摘要 |
1,147,337. Toothed and belt gearing. HENRY SIMON Ltd. 19 Sept., 1966 [5 Oct., 1965], No. 42142/65. Heading F2Q. [Also in Division H1] The casing 5 of a reduction gear unit 1 is supported on a driving or driven shaft (not shown) and is held against rotation by a torque arm connected to fixed structure by resilient means 21 adapted to yield at a predeterminal load to allow the torque arm to move axially to operate a switch 25 to disconnect or reduce the power supply to a prime mover 2 driving the gear unit through a belt or chain drive 4 or other gearing. The torque arm includes a turnbuckle 11 for length adjustment to initially tension the belt 4 and is pivoted at one end 8 to extentions 6, 7 of the casing 5. Lock nuts 17, 18 on the arm are urged against a pivotally mounted stop 15 by an adjustably preloaded tubular rubber or helical metal spring 21, the thrust of which is reacted against the opposite end of the stop 15 via a disc 20 and a sleeve 19. When the reaction torque on the casing 5 exceeds a value determined by the preloading of the spring 21, the latter yields, allowing the arm to move axially rightwards (Fig. 1) to actuate a switch 25 either directly or through a magnifying linkage to reduce or disconnect the current supply to the electric motor 2 and to initiate an alarm signal. If the prime mover is a pneumatic or hydraulic motor, the movement of the arm is arranged to directly or indirectly control a valve governing the supply of pressure fluid to the motor.
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