GB959714A - Improvements in or relating to light-current contact-making relays - Google Patents

Abstract

959,714. Piezo-electric switches. STANDARD TELEPHONES & CABLES Ltd. Feb. 15, 1963 [Feb. 16, 1962], No. 6131/62. Heading H2B. In a relay comprising an operating element formed by a strip of a piezo-electric material 2, e.g. of lead zirconate/titanate with conducting films 3, 4 and contact springs 11, 12, when an electric potential is applied between the films 3, 4, the strip 2 is deflected and contact material 9 makes contact with spring 11. The strip 2 and contact springs 11, 12 are contained in an enclosure which is evacuated or filled with an inert gas. In the operating element, overlying the films 3, 4, e.g. of silver, are insulating films 5, 6 and conductive films 7, 8 with portions 9, 10 of contact material, e.g. of diffused gold. The release of the relay is provided by the resilience of strip 2, but it may be aided by an electrical release bias. In other embodiments, a make or break contact relay may be made by dispensing with films 6, 8 or 5, 7 respectively or the strip may have a rest position between the two contact springs 11, 12, Fig. 9 (not shown), and is made to deflect in either direction depending upon the polarity of the applied potential. In further embodiments, the contact making element may be a strip projecting beyond the end of strip 2, bridging two contact members, Fig. 2 (not shown), an insulating stud acting on a pair of contact springs, Fig. 3 (not shown), or in Figs. 4, 5 (not shown), the strip may be formed with three separate parallel fingers, or wires placed within the strip may provide the contacts. In other embodiments, the operating element and contact springs are clamped at the same end of the enclosure, Figs. 11, 12, 15 (not shown).