Isolating switch shutter assembly for high voltage motor starter

Claim 1

A switching apparatus comprising a cabinet housing having a rear panel, first and second electrical terminal contact assemblies mounted in spaced locations on the interior surface of the rear panel, electrical conductor means for providing a circuit between the first and second terminal contact assemblies and comprising a movable contact member, the isolating switch structure comprising track means, said structure being movable between retracted and advanced positions of the rear panel, a carriage mounted on the track means and movable between retracted and advanced positions of the rear panel and comprising a cam, the movable contact member being mounted on the carriage and movable by the carriage between open and closed positions with the first terminal contact assembly corresponding to the retracted and advanced positions of the carriage, manual means including handle means connected to the carriage for moving the carriage between the retracted and advanced positions, a safety shutter between the movable contact member and said first terminal-contact assembly when the carriage is in the open contact position, operating means for moving the safety shutter to a retracted position when the carriage moves to the closed contact position, the operating means comprising a shutter lever pivotally mounted at one end at a fixed location and connected at the other end to the safety shutter, a cam follower on the lever, the cam comprising a pair of spaced lineal camming surfaces disposed on opposite sides of the cam follower and extending at an angle inclined to the direction of movement of the carriage.