GB1350818A - Switches - Google Patents

Abstract

1350818 Cam-operated switches DEMAG AG 13 Aug 1971 [6 Oct 1970] 38107/71 Heading H1N A switch of the pendant type, for controlling electric motors of hoists, for example, comprises a slider 1 operable to rotate a common carrier shaft 8 having a plurality of cam discs 3, 4, 5 and 6 fixed thereon, respective spring- biased rollers 15 co-operable with each cam disc to actuate respective contact sets 14, 16, the respective cam discs having roller-abutting surfaces of differing slopes interconnecting the contact-making and contact-breaking surfaces. As shown the switch has two operative positions on each side of a central off position and the cam surfaces are arranged to provide a combined effect whereby the operating force needed at the slider 1 to move from the first to the second operative position (either way from OFF) is greater than that required to move from OFF to the first position while providing a detent action to maintain the switch in any operated position (Fig. 9, not shown), also respectively smaller forces are required to return the switch towards OFF than are necessary to move it away therefrom. The cam discs are in the form of segments 3, 4, 5 and 6, one of which carries gear teeth 7 meshing with teeth 2b on a lever 2 pivoted at 2a and engaging in notch 1a in the slider 1. Each cam disc and associated contacts are housed in casing units 9 having mutually locating projections 9a and recesses 9b and are held assembled by three bolts 11. The common shaft 8 is journalled in the final casing 9 and in an end plate 12. Bridging contacts 14 interconnect individual contacts having terminal tags 21 with contacts formed by a continuous strip 16 passing through all units 9. Springs 19 urge pivoted plates 20 against stop surfaces 9c and thus assist restoration of the cam segments to the central OFF position after displacement in the respective angular direction.