GB627627A - Improvements in or relating to electric tumbler switches - Google Patents

Abstract

627,627. Tumbler switches. WALSALL CONDUITS, Ltd., and GOUGH, E. Feb. 12, 1947, No. 4078. [Class 38(v)] A tumbler switch with a short slow break, and suitable for A.C. use, comprises a dolly 12 co-pivoted at 11 to a bridgepiece 10, with a U-shaped contact arm 13 carrying a contact bridge 15. Two parallel sets of links 21, 25 pivoted together at 20 are respectively pivoted at their other ends to a lug 22 on the bridgepiece and the contact arm 13. A link 18 is pivoted at 19 between the lower legs of the dolly and at 20, whereby operation of the dolly moves the contacts 15 at a decreasing rate in the "off " direction, and the angular movement of the contact arm is less than half the angular movement of the dolly. A " mouse trap " spring coiled round the pivot pin 26 bears on the link 25, and the bottom of the contact arm thereby biassing the contacts to the "on" position. The contact-travel is completed in the first half of the dolly travel, and during the rest of the travel, the toggle formed by the dolly and link 18 goes just over dead-centre to lock the switch in the " off " position. The pivot pin 19 bears on the abutments 24 of the links 21 to hasten the closing movement.