GB1002163A - Improvements in or relating to arrangements for illuminating aircraft, machinery andlike instruments - Google Patents

Abstract

1,002,163. Indicating-apparatus. SANGAMO WESTON Ltd. April 9, 1962, No. 13608/62. Heading G1J. For illuminating a plurality of different markings on an instrument dial, such as (Fig. 1) an aircraft course indicator, a glass wedge 32 (Fig. 3), of circular form, is interposed (Fig. 2) between the scale plate 22, with its associated pointers and flags, and a mask 36 (Fig. 5) having apertures 37, 38 and 39 for the scale plate, a "to"-and-"from" flag 31 and the course-angle indicator counter 40 (41). The mask is of transparent material painted opaque and black except for the wording where it is rendered translucent, for example, by white paint. The glass wedge is cut-away at 60 and 61 to receive light, from lamps 33 and 34, entering at obliquely-cut faces 62, 63 (see Fig. 4A). The front face of the wedge is white-painted (to diffuse light externally) in the regions 55, 56a, 56b and 57 (see Fig. 3) corresponding to the positions of the translucent wording on the mask, while the rearward face is white-painted at 53 and 54 slightly above (see Fig. 6) the level of the apertures 38 and 39 so that the flag 31 and counter 40 are illuminated by rearwardly-scattered light and viewed through clear portious of the wedge. The scale plate 22 and its pointers and flags receive light refracted through the rear face of the wedge and reflected from the inner wall of the housing.