GB440257A - Improvements in or relating to electrically operated clockwork mechanism - Google Patents

Abstract

440,257. Electric clocks. LANFRANCONI, F. A., 6, Lancaster Gate Terrace, London. April 20, 1934, Nos. 11976 and 24107. [Class 139] In a clockwork mechanism, the balance comprises a permanently magnetized disc which projects into the interior of a solenoid and coacts therewith to maintain the oscillations of the balance which drives the time shaft. As shown, applied to a clock, the balance comprises a steel disc 9, having permanent magnetic poles at the ends of a diameter, mounted on a staff 11 and substantially half enclosed by the solenoid 6 contained in a casing 13 carrying the dial 14. The balance spring 10 is provided with a regulator arm (not shown), operable from outside the clock casing. During clockwise rotation of the balance, Fig. 3, a lug 16 on the staff 11 engages the hump in a leaf spring 17, fixed at 20 to the free end of a leaf-spring support 18 secured at 25 to an insulated block 19, whereby the spring 18 is moved to close contacts 21, 22 to energize the solenoid, and the spring 17 is stressed (elongated) to advance a ratchet wheel 15 which drives the hands. A pawl 23 prevents retrograde movement of the ratchet wheel. During anticlockwise rotation of the balance the springs 17, 18 are bent by the lug 16 without closing the contacts 21, 22, or advancing the ratchet wheel. The solenoid is energized when the balance is in the " neutral " position with its magnetic axis at 45‹ to the axis of the solenoid. In a modification the spring 17 is replaced by a pair of hinged arms connected by a spring to function in a similar manner. Again the spring 17 may be mounted directly on the block 19, Fig. 5, its free end coacting with a spring arm 24 carrying contact 21. In this case the solenoid is energized during each swing of the balance, but the lug 16 may be in the form of a pivoted spring- pressed pawl so as to move idly past the spring 17 in one direction, if energization of the solenoid is desired only once during a complete oscillation. According to the first Provisional Specification the magnetic axis of the disc may be perpendicular to that of the solenoid when in its neutral position. Further two or more solenoids may be used coacting with one or more armatures and excited through one or more switches. According to the second Provisional Specification the actuating member (17) may comprise a spring-biassed rigid lever of right-angled form coacting with a pivotal-sprung pawl on the balance spindle, and the armature or armatures on the balance need not be permanently magnetized.