GB391657A - Improvements in or relating to means for indicating failure of the electric supply to clocks driven thereform - Google Patents

Abstract

391,657. Electric clocks. SHEPHERD, G. R., 2, Norfolk Street, Strand, London.- (Westinghouse Electric & Manufacturing Co. ; East Pittsburg, U.S.A.) July 29, 1932, No. 21494. [Class 139. ] In a clock driven by a self-starting electric motor, one of the time-indicating members (hands) is adapted to be permanently arrested when the supply fails. The hour and minute hands 8, 9 are mounted on shafts 13, 14 respectively, connected through gearing 16 to the shaft 35 of a synchronous motor 4. The seconds hand 10 is mounted on a shaft 15 and is normally driven through worm gearing 17, 18 and clutch 19, 20 from the pinion 23. The clutch member 20 is movable axially by one arm of a bellcrank lever pivoted at 28, the other arm of which carries a pivotal armature 26 normally attracted by the stray flux from the magnet poles 5 to maintain the clutch members in engagement. When the supply fails a spring 29 rocks the bell crank to disengage the clutch members, and should the supply become available again, the stationary seconds hand indicates that a stoppage has occurred. The drive to the seconds hand 10 may be restored by depressing a button 36, a lever 31 pivoted at 33 thereby rotating the bell crank until the armature 26 is held by the poles 5. In a modification, the shaft 15 carrying the worm wheel 17, Fig. 2, is rotatably mounted in a lever 37 pivoted at 38, the worm 18 normally meshing with the wheel 17 to drive the seconds hand 10. When the current fails, the armature 26, pivoted at 27 to the arm 37, is released, and the latter falls under gravity to a stop 30 to disengage the gears 17, 18.