GB460155A - Improved photo-electric control, particularly for gas-light illumination - Google Patents

Abstract

460,155. Clockwork-actuated valves. SOUTH METROPOLITAN GAS CO., HALL, W. H. B., and WHILLOCK, R. H. July 26, 1935, No. 21287. [Class 135] [Also in Groups XL, XXXVII, and XXXVIII] A photo-electric control, more particularly for turning a gas cock, ringing a bell, or operating a locking device, comprises a clockwork motor which is adapted to be started as a result of an increase above a predetermined lower limit of the amount of light falling upon a photo-electric cell, stops automatically when its function is at an end and is then ready to be re-started when the intensity of the illumination again varies in the opposite sense to the aforementioned increase or decrease beyond the respective predetermined limits. As shown in Fig. 1, a photo-electric cell a controls a relay b, the arm c of which moves between, contacts d, e. An electromagnet f, which controls the actuation of a clockwork motor contained in a casing k for driving the gas control cock l, Fig. 2, is included in two circuits, one from battery g through contact d and switch contact h and the other from the battery through contact e and switch contact i. As shown in Fig. 2, the clockwork is arrested by contact of a rotary stop m with a projection on one arm of a double armed lever n which is urged by spring o so that its other arm n<1> engages a recess in the periphery of a disc p on the cock l. This disc has two bosses e, r of insulating material each adapted, when the disc rotates, to lift contacts h, i so that they touch contacts h<1>, i<1> respectively. As shown, boss r is in position to close contact h, h<1>. In this position, the room is illuminated by gas, the cock l being fully open. When the daylight intensity improves, the cell a moves arm c on to contact d. Contact h being already closed, magnet f is energized and armature s is attracted to lift lever n out of engagement with stop m and arm n<1> out of recess in disc p. The clockwork now starts and arm n<1> rides on periphery of the disc. At the same time contact h is opened by the onward movement of boss r so that circuit of magnet f is broken. The disc continues to turn cock l to cut off the gas supply until arm n<1> slips into the next recess whereupon the projection on lever n stands in the way of stop m. In this new angular position of disc p, boss q is beneath contact i and the circuit containing contact e is ready for energizing magnet f when the intensity of the daylight again determines the movement of arm c on to that contact. This next operation of the device turns the cook l into the " on " position and gaslight illumination is again provided.