GB471405A - Illuminating arrangements for indicating devices - Google Patents

Abstract

471,405. Clocks. GENERAL MOTORS CORPORATION. Dec. 18, 1936, No. 34823. Convention date, Dec. 26, 1935. [Class 139] [Also in Group XIX] The transparent indicia-bearing panel of an indicating device is illuminated internally by light passing through apertures in a back plate and reflected from strips situated on the front side of the panel and opposite the apertures, one or more pointers associated with the indicia being separately and indirectly illuminated from the same source of light. The invention is described as applied to indicating instruments for automobiles but may be applied to clocks and other indicators. As shown, the dial comprises a transparent disc 50 provided on its rear side with indicia 54 with which cooperate the pointers 40 of measuring instruments 10. These pointers are visible through an aperture 60 in a plate 44, the instruments being hidden by a second plate 62. A shrouding plate 46 arranged in front of the disc covers those parts of the dial that are not required for indicating purposes. The dial is illuminated by light from a lamp 24, rays from which pass through an aperture 36 in a conical reflector 34 to a reflector 56 on the front of the disc, whence they are internally reflected and illuminate the whole disc. The pointers are illuminated by light from the reflector 34 passing through apertures 38 in a cylinder 26. In a modification, the central reflector 56 is replaced by a peripheral ring of paint applied to the front surface of the dial and illuminated by one or more lamps situated at the rear of the casing. In this form, the pointers are illuminated by reflection from the white inner walls of the casing.