Low actuating force switch

In a motor starting switch comprising a housing, a flexible, resilient switch arm cantilevered in the housing, a fixed contact supported by the housing, a movable contact carried by said switch arm for making a breaking contact with said fixed contact, said switch arm being movable from an open position in which said contacts are clear of one another and a closed position in which said contacts are in engagement with one another so as to complete a circuit, a switch plunger movable along a path relative to said housing through a stroke during each cycle of the switch for closing and opening said contacts, the stroke of said plunger being greater than is required to close said contacts, wherein the improvement comprises:

• spring means interposed between said plunger and said switch arm for effecting movement of the latter from its open to its closed position upon movement of said plunger through at least a portion of its stroke, said switch having a first stiffness coefficient as it moves from its open to its closed position and a second stiffness coefficient as it undergoes additional loading exerted thereon by said spring means after said contacts have closed and while said plunger travels through the remainder of its stroke, said spring means having a predetermined spring constant, said switch arm being less stiff than said spring means as it is flexed from its open to its closed position and being stiffer than said spring means as it is further loaded by said spring means after said contacts have closed whereby the majority of the remainder of the stroke of said plunger is taken up by deflection of said spring means and the minority of the remainder of the stroke of said plunger is taken up by the deflection of said switch arm to provide increased pressure between said contacts when said switch is closed.

A switch comprising a housing, a first fixed contact, a first resilient switch arm, a first movable contact carried by said first switch arm between an open position in which said first fixed contact and said first movable contact are clear of one another and a closed position in which said first fixed contact and said first movable contact are in electrical contact with one another, said first switch contacts being normally open, a second fixed contact, a second resilient switch arm, a second movable contact carried by said second switch arm between an open position in which said second fixed contact and said second movable contact are clear of one another and a closed position in which said second fixed and movable contacts are in electrical contact with one another, said second switch contacts being normally closed, a one-piece plunger movable relative to said housing between a first position and a second position, said plunger being engageable with said first and second switch arms as said plunger moves from its first to its second position for opening said second switch and for closing said first switch, said plunger being further operable with said first and second switch arms so as to open said first switch into closed said second switch as said plunger moves from its second to its first position, spring means interposed between said first switch arm and said plunger and being engageable with said first switch arm as said plunger moves between its first and second positions, said plunger being clear of said second switch arm when said plunger is in its first position and being engageable with said second switch arm as said plunger moves from its first position toward its second position after said plunger and said spring means have begun to move said first switch arm toward its closed position.