A lawn mower or lawnmower is a machine that has one or more 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.

Many different designs have been made, each suited to a particular purpose. The smallest types, pushed by a human, are suitable for small residential lawns and gardens, while larger, self-contained, ride-on mowers are suitable for large lawns, and the largest, multi-gang mowers pulled behind a tractor, are designed for large expanses of grass such as golf courses and municipal parks.

History

Manufacture of lawn mowers began in the 1860s. By 1862, Farrabee's company was making eight models in various roller sizes up to 36 inches (900 mm). He manufactured over five thousand machines until production ceased in 1863. Thomas Green produced the first chain driven mower in 1859, named the Silens Messor. In 1870, Elwood McGuire of Richmond, Indiana designed a human-pushed lawn mower, which was very lightweight and a commercial success. On May 9, 1899, an improved cylinder mower was patented in , with the wheel placement altered for better performance. Amariah M. Hills went on to found the Archimedean Lawn Mower Co. in 1871. Around 1900, one of the best known English machines was the Ransomes' Automaton, available in chain- or gear-driven models. JP Engineering of Leicester, founded after World War I, produced a range of very popular chain driven mowers. About this time, an operator could ride behind animals that pulled the large machines. These were the first riding mowers.

The rise in popularity of sports such as lawn tennis, croquet, cricket, football and rugby helped prompt the spread of the invention. Lawn mowers became a more efficient alternative to simply relying on gardeners wielding the scythe (which, when placed in incompetent hands, left unsightly scars on and in the ground) or bare spaces caused by domesticated grazing animals. James Sumner of Lancashire patented the first steam-powered lawn mower in 1893. His machine burned petrol and/or paraffin oil (kerosene) as a fuel. After numerous advances, the machines were sold by the Stott Fertilizer and Insecticide Company of Manchester and later, the Sumner's took over sales. The company they controlled was called the Leyland Steam Motor Company. Numerous manufacturers entered the field with gasoline-driven mowers after the turn of the century. The first grass boxes were flat trays but took their present shape in the 1860s. The roller-drive lawn mower has changed very little since around 1930. Gang mowers, those with multiple sets of blades, were built in the United States in 1919 by a Mister Worthington. His company was taken over by the Jacobsen Corporation but his name is still cast on the frames of their gang units.