Speed limited fan

Abstract

The invention provides a method of driving a plurality of plastic fan blades (14) integrally molded with a band (16) about and engaging a metal driving hub (12) at an interface by rotating the fan blades (14) in unison with the hub (12) up to a predetermined rotational speed at which the band (16) flows or expands radially to create a space between the band (16) and the hub (12) whereby the fan blades (14) are allowed to rotate at a slower rotational speed than the hub (12) to prevent the fan blades (14) from bursting in response to centrifugal force. The drive connection may optionally include band projections (24) and/or male projections (26) which shear before or as the separation occurs. A film may be disposed at the interface to prevent the plastic of the fan blades (14) and band (16) from bonding to the metal hub (12).

Dependencies are inferred from the claim text.