GB355231A - Improvements in or relating to driving mechanisms for valves and other devices - Google Patents

Abstract

355,231. Electrically-actuated valves. IGRANIC ELECTRIC CO., Ltd., 147, Queen. Victoria Street, London.-(Cutler- Hammer Manufacturing Co. ; Milwaukee, Wisconsin, U.S.A.) May 12, 1930, No. 16380/31. Divided on 354,813. [Class 135.] Driving mechanism for valves and other devices comprises a reversible electric or other motor 4, Fig. 2, a frictional slip clutch 7a, 7b, and speedreducing gear 5, 6, &c., having a lost-motion device, such as an epicyclic gearing with a wheel idle for part of an initial revolution until it reaches a stop, whereby the valve &c. is started from rest with a hammer-like blow. The motor is controlled by a pair of electromagnetic reversing switches under control of a dashpot-controlled timed relay, and limit switches'operated from the driven part. The motor 4 drives through a jaw coupling 8 and friction discs 7a, 7b held in engagement by a spring 28. Electromagnetic windings 30, 31 associated with the friction discs are also arranged in conjunction with automatic switch mechanism 66, 67, 68, Fig. 4, whereby increased frictional torque can be obtained at starting. For this purpose also the disc faces are undercut to provide an air gap 32, and a nonmagnetic shaft 26 is used. The stop for arresting the gear member of the planetary gear after its initial idle run comprises a. plunger which can be withdrawn by a hand-operated cam for operating the valve by hand. The limit switches, shown at 58, 59, are controlled by cams 55, 56 on a shaft 50, connected with the driven shaft through a second epicyclic reducing gearing, and operate the reversing switches through the timed relay. The switch mechanism 41, for supplying the energizing current to the slip clutch windings 30, 31, is electrically interconnected with the reversing switches so as to supply the current whenever these are operated to start the motor. It is operated also from the shaft 50 by means of a V-shaped cam 65; this acts upon a moving contact bar 66 which carries a guide pin 70 'and a spring 71 giving a snap-over action. The cam 65 is carried by a bush frictionally engaged with the shaft 50 so as to have a small arcuate movement therewith during its initial movement only in either direction, and thereafter to slip ; this initial movement shifts the contact bar 66 from one set of contacts 67 to the other set 66 thus opening the circuit to the windings 30, 31, and cutting off the current providing for the increased starting torque.