Abstract: An apparatus for mounting an electromagnetic unit on a frame includes a mounting recess at the bottom of the main body of the electromagnetic unit, a guide recess which is communicated with the mounting recess at one side thereof so that it is normal to the mounting recess, and a slidable member which is slidably inserted into the guide recess and normally biased toward the mounting recess by means of a spring supported by a projection disposed in the guide recess, the improvement comprising a stopper disposed in a hole formed in the slidable member, which opposes the spring bearing in the guide recess. The stopper in the hole also serves as a spring guide.

Abstract: A movable contact assembly comprises a movable contact arm carrying a movable contact element, an electrically insulating contact holder for holding the movable contact arm and movable between the open and closed positions, a compression spring for resiliently holding the movable contact arm relative to the contact holder, and a spring retainer disposed between the compression spring and the movable contact arm. The spring retainer has first and second sloped guiding surfaces. The movable contact arm has first and second sloped guided surfaces thereon. The sloped guide surfaces of the spring retainer serve to guide, in cooperation with the sloped guided surfaces of the movable contact arm, the movable contact arm into a predetermined proper positional relationship relative to the movable contact holder due to the spring force of the compression spring.