Patent ID: 7343727

Claim:
A lawn mower comprising: a machine body; a grass bag detachably attached to the machine body for collecting therein grass clippings; a driving power source mounted on the machine body; a cutter blade driven by the driving power source for rotation to cut grass, the cutter blade having air lifting sections disposed at opposite end portions thereof for producing carrier air during rotation of the cutter blade; and a cutter housing covering the cutter blade, the cutter housing having a grass clipping delivery passage for directing grass clippings to the grass bag with the carrier air produced by the air lifting sections of the cutter blade, an exhaust air return passage for returning only the carrier air, as exhaust air, from the grass bag to the cutter housing, a cavity section communicating with the exhaust air return passage, and a rear wall having a plurality of through-holes communicating with the cavity section for auxiliarily returning the exhaust air from the grass bag into the cutter housing, the grass clipping delivery passage extending in a front-and-rear direction of the cutter housing, the exhaust air return passage being disposed adjacent to and extending substantially perpendicular to the grass clipping delivery passage, and the exhaust air return passage having an exhaust air inlet disposed in a rear upper surface portion of the cutter housing and an exhaust air outlet facing a rear lower end of the cutter housing.