Improvements in Thermal Electric Relays and Circuit Controllers

111,420. Graham, E. A., and Rickets, W. J. April 16, 1917. Electric switches.-In thermal switches having the contacts carried by a frame a, b, y, z, a thermal sensitive member such as the rod c being placed between the narrow ends of the frame so that, by its expansion or contraction, the circuit is controlled, the contacts g, h are mounted on levers d, e integral with and at the centres of the long sides a, b of the frame. The lower ends of the levers bear on an adjustable abutment x. When the rod c expands, the centres of the sides a, b are brought inwards, this movement being multiplied at the points where the contacts are mounted, the sides of the abutment acting as fulcra for the levers d, e. The rod is sensitive either to a heating-coil i which surrounds it or to the temperature of the surrounding medium. As shown, the rod carries the narrow ends of the frame, but these ends may be carried by blade springs mounted on the base; the rod may be arranged to slide in supports at the ends of the rod. The switch may be used to short-circuit the heating-coil, which is included in a lamp circuit thereby obtaining a constant raising and lowering of the light for flash-light signs. The switch may also replace the electro-magnetic relay e in the battery-charging system described in Specification 15769/13, the coil i replacing the coil of the relay.