Patent ID: 6953320

Claim:
A fan assembly for use in ventilation of a building, which comprises: (a) a housing having an outlet and an inlet with an inner cavity extending between the inlet and the outlet; (b) a motor mounted in the inner cavity of the housing spaced between the inlet and the outlet; (c) a center hub with a first end and a second end mounted in the inner cavity such that the first end is facing the outlet of the housing and the second end is facing the inlet of the housing and connected to the motor; and (d) blades having opposed ends with a leading edge and a trailing edge extending between the ends and mounted at one end on the center hub such that the trailing edge is adjacent the first end of the hub and the leading edge is adjacent the second end of the hub wherein the trailing edge of the blades has a rounded protrusion spaced apart from the end of the blade mounted on the center hub.