GB276040A - Improvements in projectors for colour and other light signals for railway and other purposes - Google Patents

Abstract

276,040. British Power Railway Signal Co., Ltd., Glenn, S. L., and Pierce, E. E. March 19, 1926. Signal and like lamps.-In a railway colour signal or other lamp adapted to provide one or more e secondary diverging beams which are also divergent to the main beam so that they can be seen by an observer approaching on either side, above, or below the lamp, the secondary beams are of graded intensity and merge into the main beam, but do not materially decrease its intensity, so that, when the approaching observer. is at different points, the signal indication appears to be of an intensity which is constant or may vary as desired. The apparent variation in intensity may or may not be uniform, and the secondary beams may be separate or merging into each other. Fig. 1 shows a signal lamp comprising an outer colourless lens 1 rotatably mounted in a bezel ring 14 and an inner lens 2 which may be coloured, an electric lamp 3 being situated at the focus of the lens combination. The secondary beams may be obtained by modifying the profile of a part or parts of the outer face, or of the stepped or unstepped portions of the inner face of either or both lenses, or by using an additional prismatic plate situated at any point between the source of light and the outer surface of the outer lens. The secondary beams may be made diffusing, they may be coloured, or they may be projected in the form of patch lights. The projection of the secondary beams may also be augmented by the use of additional light sources, lenses or mirrors. Specification 249,468 is referred to.