GB865565A - Improvements in or relating to valve actuating mechanism - Google Patents

Abstract

865,565. Valves. ROTORK ENGINEERING CO. Ltd. Oct. 22, 1958 [Oct. 22, 1957], No. 32966/57. Class 135. Valve actuating mechanism comprises a valve actuating spindle 1 on which is slidably mounted a clutch member 8 drivably connected thereto, e.g. by splines, spring means 56 normally urging the member 8 into engagement with a power means, e.g. the worm-wheel 6 driven by a worm 12 connected to a reversible electric motor, means, e.g. the lever 51 loaded by the spring 56, for moving the member 8 into engagement with a manual means such as the hand wheel 3, and retaining means 57 for holding member 8 in engagement with the manual means until operation of the power means causes disengagement to the retaining means whereby the member 8 under the spring 56 re-engages the power means. Normally the forked end 53 of lever 51 forces the sleeve 8 downwards until studs 43 in the worm-wheel 6 engage holes in a flange 44 of the sleeve whereby rotation of the worm-wheel and sleeve rotate an axiallyrestrained nut 7 whereby the non-rotatory screwed spindle 1 rises and opens the valve. When the valve reaches the end of its movement or meets obstruction the increased torque moves the worm shaft 5 axially to operate a limit switch 22 for the motor. On depressing lever 51 dogs 42 on the upper end of sleeve 8 engage dogs 41 on the hand wheel, the sleeve being held in this position by bevelled pawls 57 being forced by springs 65 under the flange 44. Should the electric motor be started the pins 43 displace the pawls so that spring 56 shifts sleeve 8 downwards to re-engage with the worm-wheel 6. In an alternative embodiment spindle 1 is keyed to the member 7 so that the shaft is rotated to operate a rotary valve. Backlash between 7 and 8 enables an impact to be transmitted to the velve stem for initially moving it. A disc 83 driven by the sleeve 8 is geared to a shaft 85 connected to limit switches and an indicator.