Patent ID: 8602334

Claim:
A debris vacuum comprising: a housing defining an air inlet, an air outlet, and an impeller chamber between the air inlet and the air outlet; a powered impeller located within the chamber and configured to rotate relative to the housing about an impeller axis, wherein the impeller comprises: a base comprising a first side; and at least one impeller blade disposed upon, and protruding from, the first side of the base, wherein the impeller blade comprises a first shearing edge located between a central portion of the base and an outermost radial edge of the impeller blade, wherein the first shearing edge defines a surface of revolution resulting from impeller rotation about the impeller axis, the surface of revolution being closer to the outermost radial edge of the impeller blade than to the central portion of the base; and a stationary member comprising a second shearing edge that is adjacent to, but offset in a direction parallel to the impeller axis from, the surface of revolution defined by the first shearing edge.