GB1151331A - Electric Switch - Google Patents

Abstract

1,151,331. Toggle switches; roller contacts. WESTWOOD SWITCHGEAR Ltd., and D. W. C. SMITH. 25 Nov., 1966 [20 Jan., 1966], No. 2722/66. Heading H1N. Each pole of a three pole switch has two pairs of opposed fixed contacts, 10, e.g. of copper, the upper and lower pair each being bridged by a roller contact 28, e.g. of copper, and one contact of each pair being connected by a fuse 12 (see Figs. 1, 8). A pair of fixed neutral contacts 13 (Fig. 1) are connected by a link. The fixed contacts are mutually insulated by screens 14. The six rollers 28 are carried by a carriage 20 comprising insulating blocks 22, 22a and screens 23. Carriage 20 has two bosses 35 at each end vertically reciprocatable (perpendicular to plane of Fig. 4) in slots (36, Fig. 9) in the switch housing, thus allowing rollers 28 to break with contacts 10, the blocks 22 moving between contacts 10 to limit arcing. Each roller 28 comprises two parts providing a V-groove to make point contacts with the edge 11 (see Fig. 10) of contact 10. The two parts are urged together by coil springs (30, Fig. 5) around rods (29) supported in blocks 22. The carriage 20 is reciprocated between "make" and "break" by a snap action toggle mechanism comprising a manual bell crank lever 44 coupled to a lever (40, Figs. 2, 3), with an over-centre toggle spring (41) provided at each end of the carriage 20, each lever 40 being coupled to a rockable fork (42, Fig. 9) embracing the lower boss 35. The near fixed contacts (as in Fig. 4) are secured between the screens 14 which are held on fixed bars 51. The bars 54 of the front fixed contacts are releasably latched in the housing. The fixed contacts may be series or parallel connected. The fixed contact may be in two parts spring urged away from or towards one another. The roller may have a rounded edge running in a V-groove in the fixed contact. The roller may be the fixed contact.