| 摘要 |
<p>A box fan comprising a box-like structure having front and rear openings interconnected to form a duct passing through said structure, said duct containing an electric motor and a large axial depth wide-bladed fan blade assembly operable by the motor to rotate about an axis of rotation, which fan blade assembly is so located that the center of gravity of said fan blade assembly is located near the rear opening, wherein the fan blade assembly has a plurality of blades each of which has a shape in a plane normal to the axis of rotation, which shape comprises a neck connecting the blade to a hub defining the center of the fan blade assembly, a slightly convex leading edge extending from said neck, a convex outermost edge, a slightly convex trailing edge and a chin portion connecting the trailing edge to the neck, said trailing edge being heavily set near said chin portion and being decreasingly heavily set as the outermost edge is approached along said trailing edge.</p> |
