Patent ID: 7189061

Claim:
An apparatus comprising: a) an axial cooling fan having an array of fan blades, each of said array of fan blades having a pitch that is not adjustable and extending generally radially away from an axis of rotation to cause air to move generally parallel to said axis of rotation during rotation of said axial cooling fan, said array of fan blades surrounded by a ring connected to tips of the blades, said ring defining at least one sector between tips of adjacent ones of said array of fan blades; and b) means for reducing inward deflection of said ring at said at least one sector; said means comprising a non-uniform mass integral with said at least one sector, a circumferential distribution of said mass being produced by varying the mass of the ring among a plurality of angular positions along the ring according to a computed or calculated simulation performed to determine the deflection of said ring, thereby producing a non-uniform distribution of mass in said ring to facilitate preventing inward deflection of said ring.