| 摘要 |
650,658. Multiposition switches. BAYS, F. Dec. 22, 1948, No. 33086. [Class 38(v)] A rotary switch comprises coplanar fixed contacts 15 and movable contacts 17 operated by cam discs 11 having a step-bystep movement on a common shaft 7, the contacts 17 being arranged on a circle concentrically with the cam discs on pivots 22 and having longitudinally adjustable means 24 for cooperation with one cam disc. Each contact 17 has a hub 17a which pivots on the stem 22 of a terminal 18 on the outside of the switch and has projections 17b for a pin 23 which carries a roller 24. Projections 17c on the hub are provided to position the roller at intermediate points along the hub so that only one disc at a time is engaged, and a spring 26 on the rod 22 biasses the contact 17 against its co-operating contact 15. In the switch shown the upper set of contacts 17, Fig. 2, are actuated by the one cam disc and the lower set by the other, the former being all opened and the latter all closed when the shaft 7 is rotated 30 degrees from the position shown. The step-by-step movement is imparted to the discs by rollers 31 on two spring-loaded levers 28 engaging the teeth of a star-wheel 27, Fig. 3 (not shown). The switch shown may control two 3-phase circuits or a motor having two exciting windings for two speeds or for two running directions. By varying the connections between the terminals inside the rear wall, the switch may be adopted for other purposes. A further application is to star-delta starters. The jacket 40 of the switch may be made dust-tight and water-proof. |
