Patent ID: 8100664

Claim:
An impeller adapted for being used in a cooling fan, comprising: a hub; and a plurality of blades extending radially and outwardly from a periphery of the hub, each of the blades having a pair of opposite ribs formed from two lateral sides thereof, for reducing a noise level generated by the impeller when the impeller rotates; wherein the hub comprises a circular wall and an annular sidewall extending upwardly from a periphery of the circular wall, the blades extending radially and outwardly from a periphery of the annular wall; wherein each of the blades comprises a first portion connecting with the annular sidewall of the hub, and a second portion curved outwardly from the first portion; and wherein the first portion of the blade has a top face coupling with a top surface of the annular sidewall of the hub, a pair of opposite lateral faces connecting an outer surface of the annular sidewall of the hub, and a bottom face attached to the outer surface of the annular sidewall of the hub.