GB172346A - Improvements in clocks and watches - Google Patents

Abstract

172,346. Jackson, W. J. Mellersh-, (Soc. Anon. d'Horlogerie et Bijouterie de Geneve). June 29, 1920. Dials.-Relates to clocks and watches of the kind in which a movable dial carrying chronometric indications rotates always in the same direction under a fixed dial concentric with a movable pointer, the rotation being performed by steps by a force derived from the mainspring and intermittently released to change the indication of the rotating dial appearing at a window in the fixed dial. According to the invention, the movable dial is concentric with the fixed dial and is provided with a set of teeth or like projections engaged by an operating member operated by a toothed sector alternately engaged and released by the cannon pinion. In the form shown in Figs. 3 and 4, two concentric movable dials b<1>, b<2> are used interconnected by a pinion d, the dial b<1> being marked with hour indications 1 to 24 and the dial b<2> with hour indications 1 to 12 appearing respectively at windows a', a<2> in the fixed dial a. The dials b<1>, b<2> are moved step by step by means of a pawl e' carried by a toothed sector e, which is moved in one direction against the action of a spring f by the cannon pinion i until released by a cut-away portion of the pinion, this operation being repeated every hour. A pawl h prevents backward rotation of the dials. The dial b<1> is mounted between rollers c, one of which may be pressed inwardly by a spring. The marks on the dials may indicate dates of the month, days of the week, weeks, months, seasons, years phases of the moon and so on. Various modifications of the arrangement of the dials and of the manner in which the sector is driven and operates are described.