Abstract: This centrifugal blower fan wheel has extruded-aluminum airfoil blades. The preferred blades have two hollow regions, separated by an angled mid-load support beam, inside the blade. The nose section of the blade (at the leading edge) and the tail section of the blade (at the trailing edge) have open semi-circular grooves which face the adjacent hollow sections and are designed to accept thread cutting or thread forming screws for attachment of the blade to a ring-shroud and back-plate.

Abstract: A centrifugal blower wheel including a center disc assembly and a blade assembly. The blade assembly includes a plurality of blades, each blade including a notch which is engaged over a peripheral edge of the disc assembly in frictional engagement. The peripheral edge of the center disc assembly includes axially outwardly facing surfaces for engaging edges of the notches in the blades, and the axially facing surfaces are formed as roughened surfaces, including a plurality of grooves and/or ridges, for facilitating engagement between the notches of the blades and the center disc assembly to thereby positively prevent relative movement between the center disc assembly and the blade assembly when a torque is applied to the center disc assembly to rotate the centrifugal blower wheel.