GB634790A - Improvements relating to electric push button switches - Google Patents

Abstract

634,790. Press-button retractive switches ; snap-action switches ; mechanical switches without quick action. BRITISH THOMSONHOUSTON CO., Ltd. March 17, 1947, No. 7327. Convention date, March 18, 1946. [Class 38 (v)] A switch for starting and stopping a fluorescent lamp and adapted to be mounted in the lamp-holder disclosed in Specification 618,128, is controlled by two separate but co-operating push-buttons 26, 33. The housing 10 has a partition 14 through which the spring-plunger 27 of the button 26 moves, and the button 33 carries a tube 36 containing contact balls 19 urged apart by a conducting spring 37. To start the lamp, the button 26 is pressed, whereby a contact plate 32 on the plunger 27 connects contact blades 23, 24 and the plunger 27 engages the tube 36 to snap the balls 19 over projections 38 and bridge contact blades 16, 17. This operation completes the heating circuit through the lamp filaments 22, 25 ; release of the button 26 then breaks the starting circuit and the lamp remains lit through the contacts 16, 17 which remain closed, the button 33 is pressed. In a modification, Fig. 8, pressing of the button 26 flexes a spring contact arm 45, and an extension 48 engages a conducting disc 49 on a frictionally-supported insulating button 33 so that the disc bridges the contacts 16, 17.