Importance

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Abstract

The switch comprises a casing with a shaft rotatable therein and an insulating carriage rotatable with the shaft. A contactor is mounted on and rotatable with the carriage to a central OFF position and a series of circuit closing positions spaced both clockwise and counterclockwise therefrom. The contactor is engagable with fixed contacts mounted on an insulating terminal head. A vacuum valve is operable by a cam rotatable with the contactor. The valve includes stationary and moveable valve members. The stationary valve member has a vacuum source port and a vacuum utilization port. A third port is also provided. The movable valve member is moveable along a slideway on the stationary valve member. An elastomeric sealing member is received in a recess in the slideway and is formed with portions connected to the source and utilization ports. The moveable valve member has a valve surface which is slidable along the sealing member between first and second positions. The valve surface includes port structures for connecting the utilization port to the source port in the first position of the moveable valve member, while connecting the utilization port to the third port in the second position of the moveable valve member. As disclosed, the third port communicates with the atmosphere. The cam has portions for moving the moveable valve member between its first and second positions in both directions, and other portions for locking the valve member against unwanted movement in various positions of the cam. The cam coordinates the operation of the moveable valve member with the operation of the contactor.

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First Claim