Abstract: A fan (31) and fan drive (11) assembly in which the fan includes a spider (33), typically a metal stamping, defining fastener openings (41), each including larger opening (43) and a smaller opening (45). Adjacent the smaller opening, the spider defines a raised ramp portion (47). The fan drive includes an output (13) defining fan mounting portions (21), each of which includes a head portion (25), and a shank portion (27). Upon assembly, the head portions (25) align with, then pass axially through the larger openings (43), then the fan is rotated relative to the fan drive, resulting in the shank portions (27) moving into the smaller openings (45) and the head portions (25) passing over and deforming the ramp portions (47), thus tightly engaging the fan spider (33) to the fan drive output member (13).

Abstract: An improved method of assembling a fan (31) and a fan drive (11) is disclosed in which a bolt (25) is threaded into each of the bores (23) defined by the body (13) of the fan drive. Each bolt is positioned such that the head portion (29) is separated from an adjacent surface (47) of the body by an axial dimension at least equal to the axial thickness (X) of the spider (33) of the fan assembly. The fan has keyhole shaped fastener openings (41) including a larger portion (43) and a smaller portion (45). The fan (31) is positioned on the fan drive with the bolt heads extending through the larger portions (43) of the fastener openings. The fan is then rotated relative to the fan drive to a position in which the threaded portion (27) of each fastener is received within the smaller portion (45) of the fastener opening. Finally, the bolts are tightened against the fan spider (33).