GB1361459A - Electrical contact units - Google Patents

Abstract

1361459 Mechanical switches; electromagnetic relays; switch contacts STANDARD TELEPHONES & CABLES Ltd 3 Aug 1972 [5 Aug 1971] 36834/71 Heading H1N A contact unit comprises two electrically conductive diaphragms separated by an insulating apertured spacer 30 and capable of being brought into electrical contact within the aperture of the spacer 30, at least one of the diaphragms 10 having an annular projection forming the contact-making region at which it touches the other diaphragm when said contact is made. The diaphragms may be identical, as in Fig. 3a, or one may be domed, as 20 in Fig. 4a, to provide a retractive snap-action, or, if the radius of curvature is small, a bi-stable snap-action requiring an external restoring force. The contact unit may be hermetically sealed, in which case a glass spacer is preferred and the diaphragms are of 47% nickel, 48% iron, and 5% chromium; or the diaphragms may be of beryllium copper or phosphor bronze with polycarbonate or polyimide spacer and the diaphragms may be perforated to avoid build-up of contamnment vapours. The contact- making regions may be gold plated. A single contact unit may be actuated by a bi-stable or retractive push-button (Fig. 6, not shown) or a plurality of contact units may be stacked for operation in tandem (Fig. 7, not shown) or for joint operation by a ladder-like actuator (80, Fig. 8, not shown). A dolly may act via an overcentre compression spring on a pivoted member (91, Fig. 9, not shown) to actuate alternate pairs of four contact units. A single-pole change-over micro-switch (Fig. 10, not shown) may be provided by two contact units mounted close to a central bead (101) on a resilient wand (102). A rotary switch wafer (Fig. 11, not shown) may be formed by arranging contact units (110) in a circle around the central boss of pivoted lever (111) for sequential actuation as the lever is rotated by a switch spindle. Electromagnetic actuation.-The relay of Fig. 12, comprises ferromagnetic alloy diaphragms 120 which, with the annular insulating spacer 121, form a bobbin for a winding 122. Two C-shaped ferromagnetic pieces 123 fitted in insulation 124 form an annular yoke and the diaphragms are plated at least on their inside surfaces to provide good contact-making properties and prevent intimate contact between the ferromagnetic material of the diaphragms.