Plunger operated switch unit for use in a dynamoelectric machine

Claim 1

A SWITCH UNIT COMPRISING A HOUSING FORMED WITH SWITCH ACCOMMODATING MEANS, FIRST AND SECOND SWITCHING DEVICES MOUNTED IN SAID MEANS EACH OF WHICH INCLUDES AN ASSOCIATED RELATIVELY HIGH CURRENT CARRYING MOVABLE CONTACT ARM, A PLUNGER HAVING A PORTION MOUNTED WITHIN SAID ACCOMMODATING MEANS FOR RECIPROCAL MOVEMENT BETWEEN DEPRESSED AND EXTENDED POSITIONS TO ACT UPON THE MOVABLE CONTACT ARMS THEREBY TO OPERATE SAID SWITCHING DEVICES, AND A TOGGLE SPRING DISPOSED IN BIASING ENGAGEMENT WITH SAID PLUNGER AND CONTINUOUSLY BIASING SAID PLUNGER TO ONE OF SAID POSITIONS, THE MOVABLE CONTACT ARM OF SAID SECOND SWITCH DEVICE APPLYING A BIAS TO SAID PLUNGER DURING AT LEAST A PART OF THE MOVEMENT THEREOF BETWEEN THE TWO POSITIONS, SAID TOGGLE SPRING EXERTING A FORCE ON THE PLUNGER SUBSTANTIALLY GREATER THAN THE FORCE APPLIED ON THE PLUNGER BY THE MOVABLE CONTACT ARM OF SAID SECOND SWITCH DEVICE TO PROVIDE A CONTROLLING FORCE ON SAID PLUNGER BY SAID FIRST SWITCHING DEVICE TO PROVIDE SNAP ACTION OF THE MOVABLE CONTACT ARM THEREOF, THE MOVABLE CONTACT ARM OF SAID SECOND SWITCHING DEVICE HAVING A LOST MOTION CONNECTION WITH SAID PORTION OF THE PLUNGER AND BEING OPERABLE BY SAID PLUNGER PORTION DURING A PART BUT NOT ALL OF THE RECIPROCAL MOVEMENT BETWEEN THE DEPRESSED AND EXTENDED POSITIONS, WHEREBY SAID FIRST AND SECOND SWITCHING DEVICES ARE BOTH ACTUATED BY SAID PLUNGER AND THE FORCE REQUIRED FOR OPERATING SAID PLUNGER APPROXIMATES THE FORCE EXERTED UPON SAID PLUNGER BY SAID TOGGLE SPRING.