Patent ID: RE39570

Claim:
In combination with a fan, which fan has a fan motor, a fan blade assembly attached to and driven by said fan motor, a motor housing containing said motor, a rear grill to which said motor housing is mounted, and a front grill attached to said rear grill, the improvement which comprises, a plurality of spaced radial ribs, said front grill having a center plate to which some of said radial ribs are connected, at least a portion of said radial ribs extending outwardly to a circumferential ring, said circumferential ring having a curved panel extending to a rim and an inclined panel to which said ribs are connected , said ribs connected to said inclined panel, said circumferential ring having dimensions based on a fan blade diameter D, with a dimension A of said ring being a distance from a tip of said fan blade assembly to an inside diameter of said ring, a dimension B being a depth of said ring, and a dimension C being a width of said ring, said dimension A being up to about 40% of said fan blade diameter D, said dimension B being between about 0.60 to 4.5 inches and said dimension C is between about 40 to 200% of said dimension B, and wherein said front grill provides a diffuse airflow from said fan.