GB837432A - Improvements in or relating to snap-action electric switch - Google Patents

Abstract

837,432. Snap-action switches; retractive switches. MASON ELECTRIC CORPORATION. July 4, 1956, No. 20688/56. Class 38 (5). The moving contact of a switch moves along a path having recessed contacts under the action of a snap-action means connecting the contact and the actuating means and arranged to bias the contact into engagement with the path and to snap over centre as the contact is moved in and out of a recess. The contact path 30 has two rows of contacts 34, 36, 38 with insulation between, each contact having a recess 40, 42, 44 which is not as wide as the contact. The moving contact roller 32, comprising a conducting sleeve on a magnetic core bridges the two rows of contacts and is mounted in a cage 72 which can move freely, towards and away from the contact path 30, in a carrier 62. A snap-action spring 58 between the cage 72 and carrier 62 urges the roller 30 against the contact path and the carrier 62 is held in a spring 64 attached to an operating handle 60. When the handle 60 is operated the force exerted by the spring 58 retains the contact roller 32 in a recess until the spring 64 is strained sufficiently to cause the spring 58 to snap over and allow the roller to move to the next recess and it will then be moved into the recess with a snap-action. A member 96 is mounted on the handle so as to limit the " lost-motion " of the spring 64. A spring 102 can be fitted to return the moving contact assembly to the central position when the handle 60 is released. In Fig. 10 the moving contact assembly is mounted in a rotor and the contact path is a complete circle. The rotor shaft 252 is operated by a lost-motion drive and the roller contact carrier 284 is retained by shoulders on a member 244 against the snapaction spring 248. U.S.A. Specification 2,684,843 describes a suitable snap-action spring. Specifications 837,433, 837,434 and 837,435 also are referred to.