GB187814A - Improvements in the synchronisation of clocks - Google Patents

Abstract

187,814. Shortt, W. H. Sept. 30, 1921. Synchronizing.-A pendulum clock is synchronized with another by means of the usual electric impulses which are utilized to operate a device associated with the slave pendulum immediately this pendulum lags in phase beyond a predetermined amount. In Fig. 1 the synchronized or slave pendulum D is given a losing rate and is provided with a spring-controlled lever L pivoted thereto. At a periodic impulse the armature A of an electromagnet M engages and holds the lever L (if the phase of the slave pendulum lags behind the primary pendulum) during the remainder of the swing of the pendulum to the left, and the pendulum is on its return swing accelerated by means of the spring-controlled lever L by an amount greater than that by which it previously lagged. During subsequent swings the armature will not engage the lever L if the phase of the pendulum is ahead of that of the primary pendulum, that is if the lever has passed the end of the armature at the moment of periodic impulse. Fig. 3 shows an arrangement whereby the lever L is engaged by the armature on several successive swings so that the acceleration is gradual. When the armature A is raised by the electromagnet M an armature lever V moves below it and keeps it elevated, the lever V being retracted one or more half-periods before the next impulse to the electro-magnet M by the energizing of electromagnet N through contacts made by the slave pendulum and so allowing the armature A to fall ready for the next periodic impulse. If desired the slave pendulum D may be given a gaining rate, in which case the spring S is replaced by a weight on the lever L. The engagement of the lever therefore, in effect, removes weight from the pendulum and retardation takes place.