Ac switch mechanism of the ball contact type

Abstract

An AC switch mechanism utilizes a ball contact to which generally linear motion is imparted by a rockable actuator having a spring providing downward contact force and a spring acting ball pusher leg to provide a snap action. In a single pole configuration disclosed as a typical and basic embodiment of the switch, the ball contact in one extreme position engages and extends as a conductive bridging element between bared conductor wires of an electric cable. The cable thus dispenses with the need for assembling separately made switch terminals with the other components of the mechanism. When moved from the 'on' position to its other extreme, 'off' position, the ball moves onto sloping ramps having a slight, gradual inclination relative to the lengths of the conductor wires. The construction offers a slow break to provide a minimum arc length before the zero point of the AC cycle, a characteristic of great importance in the design and operation of AC switches. Further benefits are obtained by providing a simultaneous two-point break to divide the arc and therefore reduce the arc's outward extension and tracking of the adjacent areas. The design is additionally effective to produce a fast bounce, free make to minimize contact deterioration caused by arcing at the 'make' point of the switching cycle. The need for silver alloy contacts is eliminated by providing a continuously moving point of arc termination which cools the contact surface, minimizing the volume of vaporized material, and condenses out the copper vapor during the zero point of the half cycle.