GB172591A - Improvements in or relating to clocks, watches, and like instruments - Google Patents

Abstract

172,591. Jackson, W. J. Mellersh-, (Soc. Anon d'Horlogerie et Bijouterie de Geneve). June 29, 1920. Dials.-In clocks, watches, &c. of the type in which a movable dial is arranged to rotate intermittingly in one direction beneath a fixed masking dial by means of a force which is stored up during the time the movable dial is stationary, the movable dial is mounted concentric with the fixed dial and is periodically operated by means of a cylinder escapement and a spring tension device. Fig. 2 shows a movable dial of the ring type having teeth on the inner side which teeth are arranged in two series y, z at different levels and adapted to pass through slots g<1>, g<2>, Fig. 3, of a cylinder escapement g as it is rotated through gearing from the cannon pinion 5. This pinion also drives a gear e", Fig. 5, to which is attached one end of a spring f<2>, the other end being attached to a roller d having pins d<8> which engage with the teeth of the ring dial. While the ring dial is held stationary by the cylinder escapement, the roller d is held and the spring f<2> is tensioned causing, when the ring dial is released, the roller d to move the dial with a jerk. In a modification, the spring is mounted between the cannon pinion and a concentric gear. A central disc dial may be provided which may show the hours from 1 to 12 through a second aperture in the masking-dial. The apparatus may, instead of showing the hours &c., show the dates, months, &c., or phases of the moon &c.