Mechanical interlock mechanism for a vacuum contactor

Claim 1

A vacuum contactor, comprising: a vacuum interrupter including a stationary contact and a moveable contact enclosed in an evacuated chamber with a portion of the moveable contact extending out through the chamber via a gas-tight seal, the moveable contact transferable between an open position and a closed position with respect to the stationary contact; operating means connected to the extended portion of the moveable contact for effecting relative movement of the moveable contact between the open and closed positions; a housing for enclosing and supporting the vacuum interrupter and the operating means; a shaft rotatively supported by the housing and connected to the extended portion to the moveable contact such that the movement thereof between the open and closed positions rotates the shaft through an arc about the longitudinal axis thereof; a first arm having a free end and radially extending from the shaft; roller means mounted adjacent the free end of the first arm for providing a rotatable connecting point thereon; a second arm having a free end and a slot in the other end thereof for slidably engaging and pivoting about the roller means; pivot means positioned intermediate the free end and the slot of the second arm for allowing the arcuate motion of the second arm, the radial distance between the roller means and the pivot means being less than the radial distance between the shaft and the roller means, thereby increasing the length of an arc circumscribed by the free end of the second arm in relation to the length of an arc circumscribed by the free end of the first arm as the moveable contact transfers between the open and closed positions; a third arm mounted on the housing and moveable between a first position and a second position with one end thereof adjacent the free end of the second arm, the first arm, second arm, and third arm cooperating in the following manner: (a) when the third arm is at the first position, the moveable contact can move between the open and closed positions; (b) when the moveable contact is in the open position and the third arm is in the second position, the end thereof adjacent the free end of the second arm blocks the arcuate path of the second arm, thereby preventing the moveable contact from transferring from the open position to the closed position; and (c) when the moveable contact is in the closed position, the free end of the second arm blocks the path of the end of the third arm preventing the third arm from moving to the second position thereof.