EM relay with lever arm riding around armature yoke - uses lever arm to close magnetic circuit and increase contact spring-set travel

摘要

Lever arm electromagnetic relay provides increased travel of the switch block operating end of the switch-bar. The coil (1) is located on a yoke (2) which has straight end sections (9,10) and a curved front (11,12) which acts as a fulcrum for the switch block (5,6,7) loaded (at 18) lever arm (13). The lever arm (13) pivots around the curved outer (12) of the front yoke piece (11) to make the magnetic circuit when the relay is energised (17 onto 8). The lever arm (13) travel (a) at this end is less than that (a') at the switch block operating end (18). Also the distances are adjusted as the lever arm (13) rolls around the yoke face (12). Such operation enables a greater spacing to be achieved between the contact (6,7) of the spring-set.