GB536398A - Improvements in and relating to electric switches - Google Patents

Abstract

536,398. Multi-position switches. BRITISH THOMSON-HOUSTON CO., Ltd. April 13, 1940, No. 6717. Convention date, April 13, 1939. [Class 38 (v)] [Also in Group XXXV] A switch comprises an insulating body with a recess on opposite walls of which ledges at two different levels are formed, fixed contacts extending into the recess being mounted on the ledges of one wall and co-operating spring blade contacts extending across the recess being mounted on the ledges of the other walls, together with a cam disc for operating the spring contacts, and means to rotate it, the fixed and spring contacts at the higher level and those at the lower level being respectively on opposite sides of the cam disc. As shown, a base'member 10 is formed with a recess 11 along one wall of which is a series of ledges 12, alternately at a higher and a lower level, to which fixed contacts 13, 14, 19, 26, 23, 28 are secured. A similar series of ledges 33 along the opposite wall of the recess 11 carries spring contact blades 34, 37, 40, 43, 46, 49 which extend across the recess and co-operate with the fixed contacts. The blades lie alternately on opposite sides of a rotatable cam-disc 55 having on each face a number of depressions 58 co-operating with struck-up projecting portions 53 on the blades which are thereby moved to make and break contact by rotation of the cam. The cam spindle is carried in a bearing 54 upstanding from the bottom of the recess 11 and by a bridgemember 61 secured to the front of the base 10. The end of a sleeve integral with the cam is formed with a number of faces 60 with which engage springs (not shown) secured to the bridge-member 61 to hold the cam in its various angular positions. Fig. 6 shows the connections, of the moving contacts for controlling the current from a three-wire two-voltage supply system, L1, L2' N to two heating elements A. B so as to give five degrees of heating and an "off" position, the elements being connected alternatively in parallel, series, or singly, across the supply lines, or between line and neutral.