| 摘要 |
A device for controlling the flow of water spray nozzle, comprises a valve member (E) normally biassed to a seated, closed position; an actuator (D) carried by a rotatable actuator shaft (C) and operable on the valve member (E) to displace the latter, against its bias, to an unseated, open position; a wheel (I) adapted, in use, to make frictional contact with the conveying run (K) of a loaded conveyor belt and to be rotated about an axis co-axial with that of the actuator shaft (C) by linear movement of the loaded belt, and a coupling means to couple wheel rotation to the actuator (D), and comprising firstly a disc or annulus (A) of electrically conducting material also rotatable about an axis co-axial with that of the wheel (I) and secondly a plurality of magnets (G) also carried by the actuator shaft (C) rotatable co-axially with the wheel (I) and disc or annulus (A) and located with air-gap spacing from the disc or annulus, with means to restrict the rotation of the actuator shaft (C) through a prescribed angle only.
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