GB715395A - Improvements in or relating to change-over relays - Google Patents

Abstract

715,395. Electromagnetic relays; contact members for switches. COLE, Ltd., E. K., and COPPIN, K. J. Oct. 27, 1952 [Oct. 27, 1951]. No. 25163/51. Class 38(5) A change over relay comprises a metal body F having a cylindrical cavity B4 which houses a rotatable contact carrier D co-axially with the cavity, a plurality of cylindrical cavities-such as B1 B2, B3-which open into the cavity B4 and which have their axes in the same plane which plane is at right-angles to the axis of the cavity B4, two of the cavities B1, B2 each housing a contact arm CA co-axially therewith, each contact arm having a contact adapted, under pressure of the contact springs CS, to engage a contact mounted on the contact carrier, the contact carrier being mounted in such a way that the contact thereon is movable into or out of electrical connection with either of the contact arms under the control of an electromagnet M, the arrangement being such that the contact carrier has two positions of rest, in one of which the contact thereon makes connection with one contact arm and in the other position with the other contact arm. the movable contact making permanent electrical connection with a contact on a third contact arm co-axially housed in the third cavity B2. The rotatable contact carrier is carried on a shaft S to which is secured an armature A, in the form of a quadrant, operated on by the magnet M and returned by a spring RS. In a further embodiment the spring RS is replaced by magnetic return means, Fig. 4 (not shown). The contact carrier may have two contacts, CD1, CD2, thereon co-operating with four contact arms, one of which may be earthed to the body F. The cavities B1, B2, B3 may be radially or longitudinally aligned. The pressure on the contact surfaces may be adjusted by rotating the contact carriers CC relatively to the contact arms CA; this causes a screwed wedge W to move relatively to the springs CS thus altering the distance between them. The contact carrier D is axially movable on the shaft S, thus the contact pressures are automatically equalled. Connections to the relay are made by means of co-axial plugs P.