Novel or improved tell-tale device for use in indicating whether an unseen light is off or on

摘要

255,568. Austin Lighting Co., Ltd., and Walker, C. B. May 2. 1925. Thermal switches; indicators.-For indicating the condition of an electric lamp A, such as the tail lamp of a motor-car, a strip of bimetallic material F carrying a contact f is surrounded by a winding M in circuit or in shunt with the lamp A and is adapted to cooperate with a second strip E having a contact e so as to open or close a second circuit containing a tell-tale lamp N, preferably arranged on the dash-board. By making the strips E, F of similar materials, variations in atmospheric temperature are compensated for. The switch is preferably arranged so that the lamp N is illuminated when the lamp A fails, but an arrangement in which both lamps are alight simultaneously mav be adopted. The strip E is mounted adjustably on a threaded stud G so that the relative positions of the contacts e. f can be altered, and the switch and tell-tale lamp N are supported in a single casing preferably fitted with a red window adjacent to the lamp.