an electromagnetic relay having a return pole piece , a substantially l - shaped armature and an elongated mounting spring for clamping the armature to the return pole piece . the corner portion of the armature is supported by an upper edge of the return pole piece , and the ends of the mounting spring engage the armature and the return pole piece for providing a clamping force , the line of which passes in close proximity to the supporting edge of the return pole piece to produce an armature resetting moment .