An Improved Thermal Electric Switch

374. Kelley, W. Van D. Aug. 30, 1905, [date applied for under Patents Act, 1901]. Switches, thermal, particularly adapted for intermittently flashing the lamps of an electric advertisement sign, consist of a triangular frame of metal, the base of which is fixed, and the sides of which may be of different metals riveted at the apex, which carries an electric contact. A heating-coil upon one of the sides of the triangular frame causes the apex to move to one side, breaking or completing an electric circuit. Upon an insulating-bracket 2 is fixed a triangular frame composed of two legs 5, 6 of similar or dissimilar metals. The limbs are secured together at 7, and provided with a contact 13 adapted to engage the adjustable screw contact 14, to which one of the leads of the main circuit is connected. Upon one of the legs is mounted a heating-coil 9 connected at one end to the screw 3 and to the main circuit, and at the other to the adjustable screw contact 14. The expansion of the leg carrying the heating-coil causes the apex to tilt and complete the main circuit, thereby short-circuiting the heating-coil. By suitably proportioning the heating-coil relatively to the lamps, the latter may, when the heating-coil is included in the circuit, be dimmed to any extent. The connexions may be arranged to break both the heating and the main circuit.