Ventilating system shutter with tilting blades - has hollow blades made of sheet material with overlapping ends bent over

摘要

The shutter for a ventilating system has tilting blades (3) interconnected by a set of levers so that they can be opened and closed by a drive mechanism at the top. Each blade is made of sheet material (6), with a tube (5) attached, forming the axis of rotation of the blade. Each blade consists of two pieces of sheet (6', 6"), one doubled over the other at top and bottom. The tube is not central along the blade, so that each blade has a long arm and a short arm. These doubled over ends (7, 8) are bent over at an angle between 30 and 50 deg. to the vertical plane when the shutter is closed, and the bent part overlaps that of an adjacent blade, top and bottom.