GB450573A - Improvements in or relating to variable resistance devices - Google Patents

Abstract

450,573. Regulating switches. WEST & CO., Ltd., A., and PADDOCK, W. J., Lewes Road, Brighton. April 5, 1935, No. 10573. [Class 38 (v)] A variable resistance switch having contact brushes rigidly mounted on the ends of an arm and at different distances from the axis of rotation of said arm, have the spring bias applied to said arm at a point midway between said contacts whereby said brushes are brought with equally distributed pressures into engagement with the fixed contacts over which they move. As shown in Fig. 1, the brushes 2, 4 carried by the ends of the arm 3 bear against resistance segments 1 and a continuous ring 5. The arm is biassed towards the fixed contacts at its centre by a spring 6 surrounding a stud 18 projecting from a member 7 secured to the operating shaft 20. The arm 3 itself (Fig. 2) consists of rods 3a secured at their ends by cross members 9 in which the tapered brushes are gripped by plates 22. Motion to the arm is transmitted by studs 16 projecting from the member 7 into slots 17 formed in the ends of a cradle 8 supported between the rods 3a and insulated therefrom by sleeves 10. The rods 16 also guide the switch arm in any axial sliding motion which may be produced by the spring 6. The brushes 24 taper towards the fixed contacts, as shown in Fig. 3, in addition to their taper towards the axis of rotation.