GB366150A - Electrical rheostat with a ring-shaped sliding contact - Google Patents

Abstract

366,150. Variable resistances. ULITOWSKY, A., 1, Moshkow per., and ROGALIA, N. LEVITZKY-, 13, Prjadilnaja, both in Leningrad. Oct. 4, 1930, No. 29765. [Class 37.] A variable resistance comprises an insulating tube 1 on which the resistance wire is wound and a ring- shaped sliding contact 3 for varying the resistance in circuit, the sliding contact being formed of a helically coiled wire surrounding the rheostat winding. Feet 5 of insulating material, such as that known under the registered Trade Mark " Bakelite," are secured to the tube 1 by means of forked copper bars, such as 6, which are secured to nuts 7 under which the ends of the resistance wire are clamped. A contact bar 4 is supported below the tube 1 and is carried in the feet 5 to which it is secured by nuts 8. The coil 2, which is carried in the insulating ring 3, may surround the rod 4 as well as the tube 1, or the coil may be connected to a plate 11, Fig. 3, from which resilient coils 9 are hung so as to engage the rod 4. A carrier 10 on the ring 3 is bored so as to slide on the rod 4. The helical coil 2 may contain further concentric or parallel helical coils and it may be flattened so as to give a better contact surface. The ring 2 may also be interlaced with cross springs 14 carried between collars 17a in apertures in a brass ring 17 surrounding the ring 2 so as to connect the ring 17 to the ring 2 electrically, a flattened, hinge-like extension of the ring 17 surrounding the rod 4 and being secured thereto by springs 19. Where a carrier 21, Fig. 11, on the ring 17 engages springs 19 which surround the rod 4, a separate brass ring secured to the main ring 17 surrounds the rod 4 and the embracing springs 19, which are interlaced by cross springs 20 in apertures in the auxiliary ring. An insulating handle (not shown) is mounted on the slide ring 17. The coil 2 may be formed of flat copper strip wound on edge.