GB397174A - Improvements in or relating to electro-magnetic relays - Google Patents

Abstract

397,174. Light-current relays. STANDARD TELEPHONES & CABLES, Ltd. and TERRY, R. S. G., Connaught House, Aldwych, London. Feb. 19, 1932, No. 4925. [Class 38 (v).] In a two-step light-current telephone relay of the type employed in the system described in Specification 396,704 as a line and cut-off relay in which the armature in moving through its first step with a reduced energization of the operating winding operates the relatively weak " line '' contact springs and a full, energization of the operating winding operates the stronger " cut-off " contact springs, the latter springs are, according to the invention, arranged normally to be supported at or near their free ends. As shown in Fig. 1, the armature 1 is first attracted with a resistance 2 in series with the relay winding and engages an insulating distance piece 118 attached to the contact spring 3, moving this spring out of contact with a spring 2 and into contact with a spring 4. This movement of the blade 3 moves it into engagement with a distance piece 17 attached to a spring 6, this spring normally bearing near its free end on a shoulder 12, Fig. 2, of an adjustable insulating block 10 at the front end of the winding. Owing to the relatively small operating force on the armature and the relative stiffness of the spring 6, the latter is not moved at the initial stage of the armature attraction. When, however, a circuit for the relay winding is made directly across the supply voltage, the resistance 25 being cut out of the energizing circuit, the spring 6 is raised from the shoulder 12 of the block 10 and is moved from the contact 5 into engagement with the contact 7. A spring 9 is at the same time operated by means of a further distance piece 16 to move out of engagement with a back contact spring 8. Shoulders 11, 12, 14 on the block 10 limit the upward movement of the back contact springs and the shoulder 13 limits the downward movement of the spring 7 during the restoring movement of the relay armature.