GB498113A - Improvements in or relating to the synchronisation of clocks - Google Patents

Abstract

498,113. Electric clocks. JUNGHANS AKT.-GES., GEB. Jan. 28, 1938, No. 2783. Convention date, Feb. 9, 1937. [Class 139] A method of continuously synchronizing a balance wheel g with a standard oscillation generator (a synchronous motor) consists in altering the effective length of the hairspring k, according to the difference between the rates of oscillation of hairspring and standard, by a regulator d, d<2> controlled in synchronism with the standard rate of oscillation, the outer end of the hairspring having a fixed point m of attachment. Such synchronization is also applied to a pendulum. The hairspring k is attached at its inner end to a collet l on the staff h of the balance wheel g coacting with the escape lever i. n are the normal curb pins. A fork d2 embracing the outer coil of the hairspring is on a lever d, d<1> rocked about pivot e by a pin c and an eccentric disc b on a shaft a continuously rotated by a synchronous electric motor ; which latter also winds the mainspring of the movement. The two points of the fork d<2> touch the hairspring during a certain part of each oscillation. If the hairspring varies from synchronism, the times at which the points d2 touch the spring alter the effective length thereof to correct it. In a modification, Fig. 2 (not shown), a second hairspring on staff h, identical with the hairspring, is provided for coaction with the fork d<2>. In another modification, Fig. 3, the eccentric disc b oscillates a lever o about a pivot p, this lever carrying a pin q which rubs along the inner face of the outer coil of the hairspring k. For synchronizing a pendulum, Fig. 4, the lever o oscillated by disc b rubs up and down the suspension spring t of the pendulum.