GB265485A - Improvements in or relating to electrically driven timepieces - Google Patents

Abstract

265,485. Juillerat, M. A. Sept. 15, 1926, Driving-mechanism, main spring; electric clocks and watches as described in Specification 249,078, having self-contained means for reenergizing the main spring electromagnetically by means of a circuit having two points of contacts connected in series and operated in succession, and having means for maintaining the drive during such re-energization, are provided with a shunt circuit for the electromagnet, which shunt circuit is timed to close and open so as to prevent sparking at the contacts in the circuit of the electromagnet. As in the prior case, contacts 21, 22 and 24, 25 are in series and close in succession, 21, 22 closing first. The main circuit of the electromagnet 10 re-energizing the spring 15 is 20-21-22-17-14-11-25-24-13 and 27. The contact 24 is connected electrically with a contact 37 coacting with a blade 38 carried bv. but insulated from, the member 17. This contact 37, 38 forms with a high resistance or condenser 39, a shunt across the winding 13. In the sequence given the parts act as follows :-as the spring 15 pulls the parts 14, 17, and 35 to the left, driving the clockwise mechanism, contacts 21, 22 close, contacts 37, 38 open and break the shunt circuit, and contacts 24, 25 close, thus energizing the magnet 10 which pulls the parts 15, 14, 17 and 35 to the right. During this motion to the right the pawl 35 takes over another tooth and contacts 37, 38 close, completing the short-circuit. Immediately afterwards contact 21, 22 opens. Thus sparking is prevented. Subsequently, when the pawl 35 recommences to drive the wheel 30, the teeth on the latter depress the part 36 and open contacts 24, 25. A stop 40 is provided to engage the bar 17 and is so adjusted that when this bar rests against it contacts 21, 22 and 24, 25 are all closed. This stop is to limit the movement of the pawl 35 to the left when the battery 18 is exhausted.