Rotary fluid moving device with improved hub construction and method of

Abstract

An air impeller of molded plastic construction includes a plurality of similar circumaxially arranged air moving blades and a central hub section. At the hub section, a plurality of similar axially projecting flexible fingers are formed integrally and arranged in a circumaxially spaced series to form a collet which defines a cylindrical hub cavity. A metal hub of cylindrical form and apertured centrally is disposed in the cavity and has a set screw for positive connection with a drive shaft entered in its central aperture. An arcuate clamping ring disposed about the fingers urges the fingers radially inwardly into engagement with the hub and thus retains the hub in the cavity. Radially aligned gaps in the fingers and the clamping ring receive an outer end portion of the set screw to lock the hub and clamping ring against rotation relative to the fingers. Lips may be provided at outer end portions of the fingers and a radial wall at an opposite end of the hub cavity cooperates to secure the hub axially. In a second embodiment, a tongue and groove arrangement secures the hub axially in cooperation with a partial end wall formed at outer ends of the fingers. In the method of construction, the device is molded in a conventional plastic molding operation, the metal hubs are then inserted within the fingers and the clamping ring is engaged on and about the fingers, the set screw being subsequently entered in its hub opening and in the finger and clamping ring gaps when the impeller is mounted on a drive shaft.