US Patent 9805881 Motor control center unit disconnect with interlocks

A connect/disconnect mechanism for an MCC unit, prevents a circuit breaker from being turned on while the unit is being inserted into an MCC section, until stabs of the unit have been connected to a power bus. A cam is rotatably mounted on a pivoted platform in the MCC unit, an actuating arm is coupled between a unit on/off handle of the MCC unit and the cam, and a bail is pivotally mounted on the pivoting platform and connected to a switch handle of the breaker. A cam surface in a slot of the cam is configured to engage a pin projecting from the bail, when the pivoted platform is forced in a backward direction to connect the stabs to the bus, thereby operatively connecting the unit on/off handle to the switch handle of the breaker.