SNAP-ACTION ELECTRIC SWITCH WITH FULCRUM MEANS FOR LIMITED CONTACT SLIDING AND POSITIVE-OFF TORQUE

• Main Author: LONG, ERIC L
• Format: Patent
• Language: English; French
• Published: 13.05.1980
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SWITCHES; ELECTRICITY; EMERGENCY PROTECTIVE DEVICES; RELAYS; SELECTORS

SNAP-ACTION ELECTRIC SWITCH WITH FULCRUM MEANS FOR LIMITED CONTACT SLIDING AND POSITIVE-OFF TORQUE An electric snap-action switch is disclosed having a movable contactor with oppositely inclined camming surfaces meeting at an apex on the top thereof. The contactor is centrally biased upwardly from below and cammed downwardly from above by a laterally movable operator traversing the inclined camming surfaces such that the contactor snaps laterally against vertical stationary contacts as the apex is crossed by the operator. The invention includes fulcrum means effective to stop the downward movement of the contactor before the operator crosses the apex whereby a moment arm is formed from a fulcrum to the point of operator-contactor engagement such that further movement of the operator towards the apex effectuates a torque on the contactor to pivot the contactor about the fulcrum to positively break any welds or other frictional attachments between the contacts without relying on the stored energy of the carrier biasing means, thereby affording a switch having little possibility of failure in an "on" position. The inclined camming surfaces of the contactor may be formed with compound slopes to assure constant operator pressure prior to trip point as the contactor pivots and increases the angle of inclination of the camming surface traversed by the operator. Specific embodiments of a double-pole single-throw trigger switch and a double-pole double-throw toggle lever switch are disclosed.