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A wagon (also spelt ''waggon'' in British and Commonwealth English) is a heavy four-wheeled vehicle pulled by draught animals or on occasion by humans (see below), used for transporting goods, commodities, agricultural materials, supplies, and sometimes people. Wagons are distinguished from carts, which have two wheels, and from lighter four-wheeled vehicles primarily for carrying people, such as carriages. Wagons are usually pulled by animals such as horses, mules or oxen. They may be pulled by one animal or by several, often in pairs or teams. However, there are examples of human propelled wagons, such as mining corfs. A wagon was formerly often called a wain, hence one who builds or repairs wagons is a wainwright. A person who drives wagons is called a "waggoner", a "teamster", a "bullocky", a "muleskinner", or simply a "driver". ==Terminology and design== The exact name and terminology used is often dependent on the design or shape of the wagon. If low and sideless may be called a dray, trolley or float. When traveling over long distances and periods, wagons may be covered with cloth to protect their contents from the elements; these are "covered wagons". If it has a permanent top enclosing it, it may be called a "van". Turning radius was a longstanding problem with wagons, dictated by the distance between the front wheels and the bed of the wagon—namely, the point where the rotating wheels collide with the side of the wagon when turning.〔 Many earlier designs required a very large turning radius; however, shrinking the width of the bed means decreasing the size of the load.〔 As this is a problem that carts (by virtue of their two-wheeled nature) do not face, this factor, combined with their lighter weight, meant that carts were long preferred over wagons for many uses.〔 The general solutions to this problem involved several modifications to the front-axle assembly. The front axle assembly of a wagon consists of an axle, a pair of wheels and a round plate with a pin in its centre that sits halfway between the wheels. A round plate with a hole in its centre is located on the underside of the wagon. The plate on the wagon, in turn, sits on the plate on the axle between the wheels. This arrangement allows the axle and wheels to turn horizontally. The pin and hole arrangement could be reversed. The horse harness is attached to this assembly. To enable the wagon to turn in as little space as possible, the front pair of wheels are often made smaller than the rear pair to allow them to turn close under the vehicle sides, and to allow them to turn still further, the wagon body may be ''waisted''. This technique eventually lead to further designs well-adapted to narrow areas; the front wheels of express wagons, trolleys and floats are small enough to turn under the vehicle's body. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「wagon」の詳細全文を読む スポンサード リンク
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