GB1457141A - Electric switch - Google Patents

Abstract

1457141 Magnetic switches INTERNATIONAL STANDARD ELECTRIC CORP 14 Feb 1974 [16 Feb 1973] 6754/74 Addition to 1439788 Heading H1N In a magnetic switch utilizing one or more contact units as claimed in claim 1 of the parent Application, the inner and outer portions 12, 13 of the base plate are both ferromagnetic and are bridged by armature 15 when a displaceable ferromagnetic member 18 of a magnetic circuit including a source of flux, e.g. permanent magnet 17 is in position 1 and are disconnected by the armature 15 when the ferromagnetic member 18 moves to a second position 2. As shown a flux return member 19 is slotted to guide displaceable ferromagnetic member 18. In other embodiments the flux return member 19 is replaced by a sealed magnetic contact unit, identical to unit 3 and arranged parallel to unit 3 and with its base plate facing the base plate of unit 3. The displaceable member, which may be the permanent magnet or the ferromagnetic member 18, is movable from a position bridging the central ferromagnetic regions 13 of the units in which the contact units are closed, to a position bridging the outer regions in which the contact units are open. In Fig. 5, not shown, a movable U- shaped magnetic member bridges a pair of magnetic sheet metal members secured to the central regions of the contact units in the first position to enable the fixed permanent magnet to close the contact units. In Fig. 6 (not shown), a displaceable ferromagnetic member carries a laterally extending pair of ferromagnetic arms which in the second position magnetically bridge the inner and outer regions of the base plates of the contact units to enhance the diversion of flux from the armatures. In Figs. 7 and 8, not shown, a pair of overlapping spaced ferromagnetic plates secured to the centre regions 13 of the base plates connect the regions magnetically in series. A fixed permanent magnet is provided between the outer regions and a U-shaped ferromagnetic member, one limb of which is secured to the outer region 12 of one base plate whilst the other limb is spaced from the outer region of the other base plate is mounted with its limbs adjacent the magnet polepieces. A magnetic member movable between the said other region of the other base plate and the magnet, causes flux to be diverted to the contact units or the U-shaped member depending on its position. In Fig. 9 (not shown) two contact units with ferromagnetic covers 11 are mounted side by side in a common plane. A fixed ferromagnetic member bridges the covers. The poles of a movable permanent magnet bridge the inner regions of the units in one position and cause the armatures to bridge the covers and the central regions. In its other position the poles bridge the outer regions 12 so that flux passes from the magnet through the outer region 12 of the first unit, its cover, the fixed ferromagnetic member, the cover of the second unit, its outer region back to the magnet so that the armatures are released. The switches are for push button or key switches used in telephones.