GB1363777A - Toggle mechanism - Google Patents

Abstract

1363777 Toggles; spring units; power-storing springs INTERNATIONAL BUSINESS MACHINES CORP 21 Aug 1972 [24 Sept 1971] 38856/72 Headings F2K and F2S [Also in Division H1] A toggle mechanism for a capacitive electrical switch comprises a bowed leaf spring 2 pivotally connected at its ends 4, in axial compression, between the arms of a U-shaped blade spring 3, the leaf spring 2 and blade spring 3 being respectively connected to a plunger 1 and capacitive plate 5, or vice-versa (Fig. 4, not shown), of the switch such that downward pressure applied to a keytop 7 fast with the plunger 1 straightens the toggle leaf spring 2 until an over-centre snap action is effected to lift the plate 5. Preferably plate 5 operates as one plate of a capacitive element, for connecting capacitively two dielectrically insulated conductors, and consists of a single moulded piece of high dielectric plastics. Alternatively conductive electrical contacts could be used in place of capacitive contacts. The plunger 1, toggle springs 2, 3 and plate 5 are contained in a casing 6 internally formed with projections 9 against which, on actuation of the switch, the rising plate 5 strikes to limit its upward movement and produce an acoustic signal to notify the operator that actuation of the mechanism is complete, and provide a fixed electrical minimum capacitance to give a fixed electrical base for interpreting signals. A plunger return spring 8 is provided to automatically effect reverse snap action of the switch after depression of the plunger 1 by the operator.