GB190814773A - Improvements in or relating to Switches for Supplying Electric Power. - Google Patents

Abstract

14,773. Cooper, G., and Sharp, F. C. July 11. Switches; cut-outs; couplings.-A switch is constructed so that it closes the circuit only when the current is within predetermined limits, the main object being to prevent current for lighting from being taken through the power meter. The switch comprises a blade which is moved to close contacts by inserting a plug or turning a handle, the blade being held in the closed position only when an electro-magnet set for a given current is operated. The switch also acts as a circuit-breaker. One form of switch is shown, Fig. 1 being a section, and Fig. 2 a plan. A blade a pivoted at g is provided with a pin b, and is normally held to the left by a spring c. A handle e carries an arm d and a brush j adapted to slide up inclines k and snap on to contacts m. When the handle is turned, the armd d turns the blade a and stretches the spring c, the blade a passing through the contacts without closing the circuit, which is still open at the contacts m. When the brush j has been turned on to the contacts m, the arm d leaves the pin b and the blade a is drawn back by the spring c and passes through the contacts h, thus completing the circuit: An electro-magnet n is connected in the circuit, and its armature o is arrranged so that, when sufficient current is flowing, it is moved into the path of a projection p on the blade a, which is thereby held in the closed position. The switch is combined with a wall-plug device in such a manner that the two contact-breaking devices are arranged so that one lies between' each plug and the main. In a modification, the switch is arranged to be operated by the insertion of the plug.