GB1313187A - Electric switches - Google Patents

Abstract

1313187 Position encoders CONTRAVES AG 8 Oct 1970 [31 Oct 1969] 47876/70 Heading G4H [Also in Division H1] An electric switch comprises an insulating member 1 having conductive tracks 23 covered by an insulating layer 3 bonded to member 1 and having holes 30 to allow contact fingers 51 to contact tracks 23, plate 1 and fingers 51 being relatively movable. As shown, tracks 23 are in the form of printed electrically separate sections of concentric circles connected to plug terminal strips such as 210. Contact fingers 51 are all connected together and are mounted on a rotatable switch wheel 41 provided with actuating projections 42 and a detent spring 6. The electrical input is to terminal strip 210 and thence to the innermost track which is not covered by insulation so as to be continuously in contact with a finger 51, and then through the other fingers 51 and holes 30 to the other tracks 23 and their plug terminal strips. Thus an electric binary signal can be taken from the terminal strips in accordance with a code which is determined by the pattern of the openings 30 and the instantaneous position of switch wheel 41. Insulating layer 3 may be a foil of polyester or polyimide or tetrafluorethylene bonded on, or may be insulating material printed on or sprayed on and hardened or applied by vaporization in a vacuum.