Opening and closing system for shutter hinged to wall of building has chain drive with two runs of chain passing through aperture in wall to sprocket on shutter and drive sprocket on inside of wall

摘要

A shutter (10) hinged to a wall (14) of a building is opened and closed by a chain drive (38). The chain runs over a sprocket (40) on the same axis as the hinges holding the shutter. Two runs of the chain pass side-by- side through an aperture (16) in the wall to a drive sprocket on the inside of wall. The drive sprocket may be turned using a handwheel and bevel gears the chain passes through drive bushes (48,49) on either side of the wall aperture.