GB727514A - Improvements in or relating to clocks - Google Patents

Abstract

727,514. Clocks. VITTORIO, R. Z. Nov. 20, 1952, [June 18, 1952.] No. 29362/52. Class 139. A clock comprises at least one body of revolution provided with hour and/or minute markings arranged along spaced helical paths and associated with indicator means arranged along a helical path or paths, the hour and/or minute markings and indicator means being relatively rotatable about a common axis so that the indicator means will be directed to the correct hour and/or minute of the day. In the first example, Fig. 1, two coaxial cylinders, 1, 1<SP>1</SP> carry respectively the hour and minute markings arranged along helical lines 2, 2.<SP>1</SP> Transparent cylinders each having a helical index line 3, 3<SP>1</SP> surround the cylinders 1, 1<SP>1</SP> respectively. A clockwork or electric motor is arranged to cause relative movement between each of the cylinders 1, 1<SP>1</SP> and its corresponding index 3, 3<SP>1</SP>. In the example of Fig. 2, a circular vernier scale 4 provides a more accurate reading of the minutes. In the third example (Fig. 3, not shown) the indices 3, 3<SP>1</SP> are formed by the helical edges of opaque members. In a further example (Fig. 4, not shown) the indices are formed as helically arranged apertures on opaque cylinders. In the fifth example, the hours are marked on helical lines on a cylinder and the index is formed by a series of helically arranged apertures 11 in an opaque cover 10. The minutes are marked on vertical scales 12 and the minute index comprises a helical mark 13. The marks can be variously coloured and/or in relief. The marks may be provided on a truncated cone instead of a cylinder.