Mulching allows for maintaining an even soil temperature, controlling weeds and enriching soil, whereby a mixture of organic material (such as straw, peat moss or leaves) is spread over a landscape. When grass clippings from a lawn mower are sufficiently reduced in size to small particles, they may serve as a mulching agent. Conventional mowers, however, are incapable of refining grass clippings to a sufficiently small size. The typical lawn mower propels a rotary blade to cut grass into clippings and either deposits those clippings onto the lawn or directs them into a catcher. Clippings discarded on a lawn take weeks to decompose and can turn to a thatch and smother the soil rather than fertilizing it, unless the clippings are raked and removed. Catchers are undesirable since mowing must be interrupted frequently to empty the contents of the catcher. In either event, the wasted time could be better spent cutting additional grass.
Alternatively, mulching lawn mowers reduce expenses, increase crew efficiency and decrease waste. Mulching lawn mowers are designed to cut grass clippings into tiny particles that decompose quickly once returned to the lawn, providing nourishment and moisture to the underlying soil. In theory, mowing time can be cut, fertilizer, trash bag and water expenses reduced, and productivity enhanced. Unfortunately, mulching lawn mowers used today are only useful under special conditions, do not work adequately in thick or heavy grass and require frequent maintenance. For example, mulching mowers normally require short, dry grass, flat landscapes and frequently honed blades. These mowers also leave uncut strips that necessitate recutting, especially on lawns having a high moisture content, tall grass or hills. In addition, moist grass that is cut has a tendency to stick to the underside of the conventional mulching mower, reducing the mulching capability and eventually dropping clumps of grass on the lawn and/or paved areas.
Conventional mulching mowers suffer from the foregoing shortcomings or they are too complex to operate reliably. For example, U.S. Pat. No. 5,117,616 to McLane discloses a mulching lawn mower that deposits clippings in front of the mower for recirculation. McLane's mower comprises a deck which covers a rotating blade and a curved deflector which lies adjacent an opening provided in the deck between the front wheels. The deflector redirects air and grass exiting the opening downward in front of the mower. The positioning of the opening and deflector at the front of the deck allows the mower to run over grass clippings a second time, but if the grass is too wet, the opening clogs and suction under the deck becomes insufficient to lift the wet clippings off the lawn and into the cutting area.
An air-floated mulch recycle system, issued to Fassauer in U.S. Pat. No. 5,123,235, employs an air-floated housing having a rotatable cutting blade, an open bottom, an air intake opening conduit and a rear discharge port. A mulch recycling system comprised of a conduit attaches to the discharge port to receive grass clippings produced by the mower for delivery to the front of the mower for recutting. An air impeller means pressurizes air to float the mower, but inhibits the mower's ability to draw grass clippings into the mulch recycling system. Moreover, dry grass is preferred for cutting since wet clippings are difficult to lift into the blade, stick to the underside of the housing and clog the tubular chute used in the mulching system.
Another mulching device is disclosed in U.S. Pat. No. 5,048,279 issued to Badawey, and is utilized as a leaf mulcher for use with a rotary blade lawn mower. The leaf mulcher comprises a rotary blade lawn mower, a grass outlet and a screen mounted on the mower over the outlet. The screen provides a cutting edge for leaves dispersed from the outlet of the mower but does not facilitate the mulching of grass clippings, is easily clogged and is ineffective on damp lawns.
Another inherent problem with prior art mulchers is their inability to be used effectively in locations with severe space constraints. Hand-adjustable mulch plates must initially be positioned at a proper height and, if a tight corner is approached or a change in grass density occurs, must then be re-positioned at a different height, a task usually involving loosing the attached plate, re-positioning it, and retightening the attachment mechanism. Re-positioning the mulch plate to achieve a different height is time consuming. Re-adjusting the mulch plate to accommodate different grass heights and space-restricted areas may result in a significant increase in total job time.
While the aforementioned background art discloses various designs for mulching debris from a rotary lawn mower, there is presently no disclosure of a low profile mulcher that is adaptable to most mowers and capable of reducing clippings of various types (e.g., high grass or wet grass), and under diverse conditions, to a mulch for discarding as a nutrient into lawns. Further, there is presently no mulch design incorporating a mulch plate controller that allows the user to easily raise and/or lower the mulch plate to one of a variety of different heights without the need to manually lift the plate and move it to a different position.
There is, therefore, a need for a mulching lawn mower that is able to reduce clippings from tall and wet lawns into fine particles for depositing the particles back into the lawns as a fertilizing nutrient and incorporating a handle-operated controller to adjust the height of the mulch plate to a variety of settings in order to accommodate different mulching conditions. This invention is intended to solve the problems not adequately resolved by the background art.