GB846041A - Improvements in or relating to power driven actuating mechanism for valves - Google Patents

Abstract

846,041. Valves. PHILADELPHIA GEAR CORPORATION, [formerly PHILADELPHIA GEAR WORKS Inc.]. Feb. 17, 1958 [June 27, 1957], No. 5104/58. Class 135. In a power-operated, screw-actuated, rising stem gate-valve having a valve body B, Fig. 1, surmounted by a yoke S guiding an actuating- spindle P operable by a drive-nut driven through worm and worm-gearing by an electric motor 13 having declutchable means whereby the valve may be hand-operated in the event of power failure, the drive-nut is associated with a thrust or shock-absorbing device to protect the valve parts against strains and possible damage when the member seats at the end of valve closing or due to heat expansion of the valve stem. The drive-nut 30, Fig. 6, rotatably connected by splines 32 to a sleeve 25 rotatable by worm and worm-gearing 29, 28 and held against axial movement by conical thrust-bearings 26, 27, is held against axial downward movement by a sleeve shoulder 31 and permitted of limited upward movement by an adaptor member 34 rotatable with the nut. The member 34 rotates in a thrust bearing which may have either coned elements or balls and is loaded by a spring consisting of a bank 47<SP>1</SP> of Belleville spring washers. The top of a spring retainer 42 engages a cam portion 93 of a rocker arm 92 mounted on a shaft 91 carrying a pointer 95 which co-operates with a scale 96 to give an indication of the thrust exerted on the valve stem by the valve closure member. In another embodiment, the adaptor member 34<SP>1</SP>, Fig. 5, has an extension sleeve 53 secured to it by a setscrew 54, the thrust recorder means V coacting with the top end of the sleeve. The sleeve 53 is rotatably keyed to a gear member 63 which through a train of gears 71, 73, 75, Fig. 2, rotates a spindle 76 carrying a pointer 79 which co-operates with a pointer 80 to indicate the position of the valve member relative to its seat. The motor 13 is fitted with the usual cut-out switches to stop the motor just prior to the full opening and closing of the valve.