US Patent 8128296 Shutter assembly

A shutter assembly includes a plurality of shutter blades movable between an open position and a closed position, a drive ring having first and second oppositely-facing sides, at least one of the shutter blades being movably coupled to the first side, and a first permanent magnet coupled to the second side of the drive ring. The shutter assembly also includes a first solenoid selectively energizable to alternately attract and repel the first permanent magnet along an arcuate path beneath the first solenoid, thereby transitioning the plurality of shutter blades between the open and closed positions. The shutter assembly also includes a sensor assembly configured to detect a location of the first permanent magnet along the path.