Abstract: A mulching rotary lawn mower which returns cut grass particles into a lawn wherein the mower is designed with an open air flow system. The mower comprises a rotary blade pivotally mounted beneath a deck. The deck includes an opening therein, providing an outlet for air drawn beneath the deck by the rotating blade and the grass clippings which are cut by the blade. A curved deflector is positioned proximate the blade to redirect the air and grass clippings exiting the opening. The air and clippings are redirected back beneath the deck, where the air drawn beneath the deck raises the clippings toward the blade where they are cut into tiny particles driven into the lawn and soil below.

Abstract: A lawn mower height adjustment linkage which is actuated by the rotation of a hand crank mounted on the mower's handle. The linkage raises or lowers the lawn mower deck relative to the ground by moving all four wheels of the mower simultaneously. The hand crank is threaded so that the mower height can be set at an infinite variety of positions. The location of the hand crank on the handle allows safe operation of the height adjustment linkage even when the mower is running. The wheels of the mower are mounted on bell cranks which are pivotably pinned to the mower so that rotation of the bell cranks will raise or lower the wheels relative to the mower. The bell crank corresponding to the left front wheel is linked to the hand crank through a connecting rod and a rotatable pivot arm, the pivot arm being mounted on the lawn mower handle.

Abstract: A closed-loop lawn mower vacuum apparatus which utilizes the centrifugal forces created by a rotating grass cutting blade to impel grass clippings and other solid debris through an exhaust chute to be automatically deposited in a fully enclosed, rigid, one-piece grass catcher. The grass clippings and other solid debris are entrained in a flow of air which is forced into the grass catcher. The air within the grass catcher is returned beneath the mower through a return chute, and recirculated through the closed loop system to remove any debris still entrained in the air flow. The inlet port of the return chute and the grass catcher are shaped so that solids will automatically be removed from the air flow within the grass catcher. Also, the discharge port of the return chute, located beneath the lawn mower deck, is partially enclosed by a shroud which directs the flow of solids out of the grass catcher so as to be recirculated through the system, and not left uncollected on the lawn surface.