Electromagnetic relay

Abstract

An electromagnetic relay comprises an elongated coil bobbin having an axially extending bore and carrying therearound an excitation coil, a generally U-shaped yoke with first and second yoke members, and a generally U-shaped armature with short and long legs connected by a web. The yoke and the armature are magnetically coupled together partly within the axial bore of the coil bobbin to form a magnetic circuit with the excitation coil such that the armature is movable between a set position of closing a relay contact and a reset position of opening the relay contact. The first yoke member extends into the axial bore to define at its free end a first pole end while the second yoke member extending outwardly of the excitation coil to define a second pole end. The short armature leg extends into the bore in an overlying relation with the first pole end, while the long armature leg extends outwardly of the coil in adjacent relation to the second pole end. The armature defines a bearing edge at an inner corner between the web and the short leg and is pivotable relative to the yoke with the bearing end supported on a pivot edge formed at the end of the first pole end. A hinge spring is fitted into the axial bore of the coil bobbin to urge the bearing edge of the armature against the pivot edge of the yoke at an optimum contact pressure.