Patent ID: 7891951

Claim:
A fan comprising: a rotatable center member to rotate in a direction and centered relative to an axis of rotation of the fan; and, a plurality of blades radially extending from the rotatable center member, each blade having a side profile being non-linear and comprising: a single notch pointed in a direction opposite of the direction in which the rotatable center member rotates, the notch extending only partially through the blade, the notch centered at a midpoint between the top of the blade and the bottom of the blade along an entirety of the notch, and the notch ending at one of a first end of the blade at which the blade is mounted to or extends from the rotatable center member and a second, opposite end of the blade, the notch running parallel to the top and the bottom of the blade along the entirety of the notch, the blade having a lesser thickness at the notch than at all other portions of the blade, wherein the single notch is an only notch in each blade.