GB137075A - Improvements in colour screens for lamps - Google Patents

Abstract

137,075. Burkinshaw, W. Dec. 31, 1917. Lamp and flash signals.-A colour-changing attachment for signalling-lamps comprises a pile or series of superp o s e d translucent disks, some of which have coloured and plain sectors, others having black or opaque and plain sectors, the disks being relatively rotatable in order to bring the desired colour into operation, or to transmit white light. Tn the arrangement shown, red, green, or white light is obtained at will by part-rotation in one or the other direction of a control sleeve 42 in which the disks are mounted, the device being arranged in a cylindrical casing 15 adapted to be attached by keyhole slots 16 to the front of the lamp. Four disks 11 - - 14 mounted in annular carriers 17 are provided. The first disk 11 is fixed to the casing 15 and is divided into sectors of 30 degrees of are coloured consecutively white, green, and red reading clockwise. The second disk 12, Fig. 5, is similarly divided into consecutive white, red, and green sectors. The third and fourth disks 13, 14, Figs. 6 and 7, are each divided into black and white sectors, the white sectors being twice the width of the black sectors. The disk 12 is fixed to the outer control ring 42 and is rotatable through 60 degrees between stops 21, 22 in the fixed casing. The disk 13 is capable of rotation through 30 degrees between stops 28, 29 in the casing, being operated with a lost motion of 30 degrees by the control ring, studs 30, 31 on the control ring engaging shoulders 32, 33 on the disk for this purpose. Also engaging with the shoulders 32, 33 is a spring detent 34 housed in the handle 43 of the control ring and adapted to be pushed up out of engagement with the shoulders by fixed cam-surfaces 35 on the casing, so arranged that the lost motion of the disk 13 occurs in the later part of the movement. The fourth disk 14 is rotatable through 30 degrees between stops 36, 37 in the casing and is formed with a lug 40 engaging stops 38, 39 in the control ring, allowing a lost motion of 30 degrees in the first part of the movement. A spring-pressed ball 46 retains the disk 14 in the adjusted position. The arrangement is such that, when the operating-handle 43 is in the central position, the coloured sectors are covered by the black sectors, and white light is transmitted through four 30-degree sectors. When the handle is moved to the left, as shown in Fig. 1, the two black sectors and the green sectors are coincident, and red light is transmitted through four 60-degree sectors. Green light is transmitted similarly when the handle is moved to the right of the central position