Patent GB-882849-A (GB)
Title: Power and manual operating means for fluid-control valves
IPC: F16K31/05
Filed: 1959-06-16
Abstract: 882,849. Clutch control. PHILADELPHIA GEAR CORPORATION. June 16, 1959 [Feb. 16, 1959; March 25, 1959], No. 20582/59. Class 80 (2). [Also in Group XXIX] Construction.-A gate valve has a threaded stem having an axially fixed nut formed externally as a worm-wheel that engages a wormshaft 33, Fig. 3, the drive to which may be from a hand wheel via a shaft 37 or a reversible electric motor through a shaft 47. The shaft 37 has a gear 38 fixed thereto by an angled pin 71 whilst splined on to the shaft 33 is a collar 40 incorporating a gear 39 meshing with gear 38, a spring 108 being disposed between the collar 40 and a ring 110 loosely surrounding the collar. Journalled upon the other end of the shaft 33 is a gear 45 meshing with a gear 46 - on the shaft 47 whilst a cam 138 with a nose 146 is keyed upon the gear 45. The nose 146 co-operates with a flipper assembly 148 that is carried by a spring-loaded throw-out mechanism 150, pivoted upon a transverse shaft 15], and incorporating forked arms that engage the ring 110 whereby rocking of the shaft 151 will move the collar 40 against the spring 108 so disengaging gears 38, 39 and engaging dogs 42 on the end of the collar 40 with similar dogs 43 on the adjacent end of gear 45. The flipper assembly 148 is mounted upon a pin 160 for limited rotational movement relative to the throw-out mechanism 150, the two parts being normally maintained in the positions shown by a spring 180, the ends of which engage pins 171, 172 in the throw-out mechanism and flipper assembly, respectively, the former being provided with shoulders 190, 191, Fig. 11, to limit the rotary movement of the flipper assembly. The latter incorporates arms 195, 196 with rollers at the ends thereof which contact the nose 146; the throw-out mechanism also includes a latching bar 210. A rocker shaft 220, Fig. 3, mounts bifurcated latching levers 224, 225 urged counterclockwise by springs 226, 227, the upper arms 240, 241 of the levers co-operating with pin 71 and the lower arms 242, 243 of the levers straddling the bar 210. Electric actuation.-To operate the valve electrically the electric motor is energized so rotating shaft 47 and hence gears 46, 45 and cam 138; when the cam nose 146 engages the roller on either arm 195, 196, Fig. 11, dependent upon the direction of rotation of shaft 47, the flipper assembly rotates until shoulder 190 or 191 contacts a surface 192 on the flipper assembly, whereupon continued rotation of the cam 138, Fig. 3, causes the throw-out mechanism 150 to rock and disengages gears 38, 39 so breaking the manual valve drive and shifting the collar 40 to engage the dog clutch 42, 43 and couple the gear 45 to the worm-shaft 33. The spring 108 facilitates indexing the dog clutch, and provides a lost motion connection so that whether or not the dog clutch is immediately indexed the throw-out mechanism 150 may rock sufficiently to permit either of the lever arms 242, 243 to engage the bar 210 so that if the pin 71 is in a position to prevent either lever from engaging the bar 210 the other lever will coast with the bar. Manual actuation.-To operate the valve manually the shaft 37 is rotated whereby the pin 71 abuts the lever leg 240 to swing the opposite leg 242 out of engagement with the bar 210 so that a slight return rocking motion of the throw-out mechanism 150 causes the leg 243 of the other lever to engage the bar 210 after which continued rotation of shaft 37 brings pin 71 into contact with lever leg 241 and disengages leg 243 from the bar 210. In the meantime leg 242 cannot return to engage the bar 210 due to the return rocking action of the throw-out mechanism; the latter is now unlatched and pivoted by its loading spring so breaking the dog clutch connection and returning the mechanism to the position shown whereby the drive from shaft 37 is transmitted to shaft 33 via gears 38, 39.