A lawn mower is a machine that makes use of revolving blades to cut a lawn at an even length.
Lawn mowers employing a blade that rotates about a vertical axis are known as rotary mowers, while those employing a blade assembly that rotates about a horizontal axis are known as cylinder or reel mowers.
Plenty of different designs have been made, each suited to a specific purpose. The smallest types, pushed by a human, are suitable for tiny residential lawns and gardens, while larger, self-contained, ride-on mowers are suitable for giant lawns, and the largest, multi-gang mowers pulled behind a tractor, are designed for giant expanses of grass such as golf courses and municipal parks.
The cylinder mower carries a fixed, horizontal cutting blade at the desired height of cut. Over this is a fast-spinning reel of blades which force the grass past the cutting bar. Each blade in the blade cylinder forms a helix around the reel axis, and the set of spinning blades describes a cylinder.
Of all the mowers, a properly adjusted cylinder mower makes the cleanest cut of the grass,[1] and this allows the grass to heal more quickly. The cutting action is often likened to that of scissors; however, it is not necessary for the blades of the spinning cylinder to contact the horizontal cutting bar.[1] If the gap between the blades is less than the thickness of the grass, a neat cut can still be made.
There's lots of variants of the cylinder mower. Push mowers (illustrated) have no motor and are used on little lawns. As the mower is pushed along, the wheels drive gears which quickly spin the reel. Typical cutting widths are 12 to 20 inches (510 mm).
The basic push mower mechanism is also used in gangs towed behind a tractor. The individual mowers are arranged in a vee behind the tractor with each mower's track slightly overlapping that of the mower in front of it. Gang mowers are used over large areas of turf such as sports fields or parks.
A gasoline engine or electric motor can be added to a reel mower to power the reel, the wheels, or both. A typical arrangement for residential lawns has the motor spinning the reel while the operator pushes the mower along. The electrical models can be corded or cordless. Some variants have only 3 blades in a reel spinning at great speed, and these models can cut grass which has grown long for ordinary push mowers.[1] One type of reel mower, now largely obsolete, was a powered version of the traditional side wheel push mower and was used on residential lawns. An internal combustion engine sat atop the reel housing and drove the wheels, usually though a belt. The wheels in turn drove the reel, as in the push mower.
Greens (roller) mowers are used for the precision cutting of golf greens. The reel is followed by a large roller which smooths the freshly cut lawn and minimizes wheel marks. Due to the weight, the engine also propels the mower. Much smaller and lighter variants of the roller mower are sometimes used for little patches of decorative lawns around flower beds, and these have no engine.[1]
Riding reel mowers are also produced. Usually, the cutting reels are ahead of the vehicle's main wheels, so that the grass can be cut before the wheels push the grass over onto the ground. The reels are often hydraulically powere
Most rotary push mowers are powered by internal combustion engines. Such engines can be either two-stroke or four-stroke cycle engines, jogging on gasoline (petrol) or other liquid fuels. Internal combustion engines used with lawn mowers normally have one cylinder. Power usually ranges from three to five horsepower (1.5 to 6.75 kW). The engines are usually carbureted and require a manual pull crank to start them, although electric beginning is offered on some models. Some mowers have a throttle control on the handlebar with which the operator can alter the engine speed.[2] Other mowers have a fixed, pre-set engine speed. Gasoline mowers have the advantages over electric mowers of greater power and distance range. However, they generate substantial pollution[3] and their engines require periodic maintenance such as cleaning or replacement of the spark plug and air filter.[4][5]
Electric mowers are further subdivided in to corded & cordless electric models. Both are comparatively quiet, usually producing less than 75 decibels, while a gasoline lawn mower can be as loud as 95 decibels or more.[6] This type of mower may even be safer to operate as they come equipped with a dead man's switch to immediately cease the motor when it is not being operated.
