GB966399A - Improvements in or relating to electromagnetic relays and contact assemblies therefor - Google Patents

Abstract

966,399. Electromagnetic relays. POSTMASTER GENERAL. Feb. 14, 1963 [Feb. 14, 1962], No. 5704/62. Heading H2B. A sealed magnetic change-over contact device comprises a magnetic reed tensioned into engagement with a non-magnetic reed extending from the same end of the tube and a magnetic reed extending from the other end. In Fig. 1, non-magnetic reed 5 carries a cylindrical insulating spacer 6. On energization of a coil 7 reeds 4 and 5 disengage prior to reeds 4 and 2 engaging. In an alternative arrangement the cylindrical spacer is replaced by an insulating member joining reeds 2 and 5 together. In the make-before-break device of Fig. 3 a magnetic reed 14 is tensioned into engagement with a non-magnetic reed 15 carrying an insulating spacer 16 and a magnetic reed 12 and non- magnetic reed 18 having a stepped portion 19 extend from the opposite end of a glass tube. In Fig. 4 magnetic reeds 22, 24 extend from opposite ends of a tube, reed 24 being tensioned into engagement with a non-magnetic reed 26 carrying a spacer 26. A further non-magnetic reed 28 extends beneath magnetic reed 24 such that when the device is energized reeds 22, 24 engage via reed 28. In an alternative arrangement the device is similar to that shown in Fig. 1, but the magnetic reeds do not overlap and the non-magnetic reed carries no insulating spaces. On energization the magnetic reeds tend to align axially allowing the non-magnetic reed to change over. The magnetic reeds are made of nickel iron and non-magnetic reeds of nickel silver. The magnetic and non-magnetic reeds may be pretensioned together by inserting them into a jig and then either sliding a glass tube over them and sealing them to the tube or securing them into a plug which is subsequently sealed into a tube.