GB440907A - Improvements in or relating to electric contact making relays - Google Patents

Abstract

440,907. Magnetic switches. GREENLY, H., 66, Heston Road, Heston-Hounslow, Middlesex. Oct. 10, 1934, No. 28951. [Class 38 (v)] In an inductor relay for use with lifts &c., in order to prevent inaccurate operation due to lift " float " and to obviate incorrect operation of the armature when mechanical vibrations are transmitted to the relay, an armature 15 normally attracted towards the poles of a permanent magnet is released therefrom on the passage between the armature and magnet of an inductor plate 5 of magnetic material, and the pivoted armature and carrier 15 is connected by a knuckle joint 11, 12 to a separately-pivoted counterweight 4, 16 which is substantially identical mechanically so that rotation of either of these members in one direction produces rotation of the other in the opposite direction. The knuckle joint comprises a spherical-ended member 12 sliding in a cylindrical hole in the member 11, the hole being as nearly as possible of the same diameter as the sphere without producing binding action. Thus if mechanical vibrations or shocks are transmitted in working to the relay as a whole any inertial force tending to move the armature is neutralized by the corresponding oppositely-acting force on the counterweight. The armature-retracting spring 9 is connected between the members 2, 4 and its force may be varied by moving it into different notches in these members, so varying the sensitivity of the relay. A contact pin carried by the armature engages a fixed contact when the armature is released. A U- shaped permanent magnet f is employed held within the casing 3 by packing pieces 38 though an E-shaped magnet with a central pole and two outside poles, may, alternatively, be employed.