GB1516541A - Electromagnetic relays - Google Patents

Abstract

1516541 Electromagnetic relays MATSUSHITA ELECTRIC WORKS Ltd and H SAUER 23 May 1975 [13 Dec 1974 24 Feb 1975] 22987/75 Heading H1N An electromagnetic relay comprises an armature 3 arranged within a protective tube 2 forming part of a coil bobbin, terminals 40, 5, 5<SP>1</SP>, 5<SP>11</SP>, embedded in the bobbin, two pole shoes 6, 7, in a chamber 8 connecting with the protective tube, and a permanent magnet 13 in a further chamber 12 connecting with the chamber 8 such that the chambers 12, 8, and protective tube 2 form a space which extends through the whole length of the bobbin, the space being sealed and closed at one end by the magnet 13 and at the other end by a sealing cap 34. The armature serves at its free end as the movable contact and parts of the pole shoes serve as the fixed contacts. The sealed space is filled with a protective gas and may contain a molecular sieve or its walls may be coated with a getter material and/or the magnet 13 is made of activated barium ferrite and rare earths to act as a getter: hermetic sealing is effected by ultrasonic welding of the sealing cap and potting at the magnet end of the space by compound 58. A can 57 of ferromagnetic material screens and protects the relays, and this can may be hermetically sealed. The magnet 13 may be centrally positioned between the pole shoes to provide a relay with an armature having a central neutral stable position, or may be nearer one pole shoe than another to provide a biased relay where the armature rests stably against one or other pole shoe contact, Figs. 5 to 7, not shown. The coil bobbin may be made of two interengageable halves which are welded together during manufacture and in this case one half has grooves co-operating with ribs formed in the other half: to ensure at assembly the correct separation of the pole shoes respectively in the two halves of the bobbin an assembly gauge is used. The terminals of the coils and of the contacts may be formed as precut plates which are severed to separate the contacts, Fig. 8 and 9. not shown. The relay may be formed to have a dual-in-line casing. The armature of the relay comprises a leaf spring welded to an elongate ferromagnetic plate, or simply a ferromagnetic spring, and may be forked to provide twin contacts, Fig. 18. not shown. Further when it is required that the armature shall have a predetermined centred position adjusting springs are positioned on either side of it, Figs. 16, 17, not shown.