The trolley (the wheel barrow; barrow; hand truck) is a human push, pull the vehicle's handling, which is the ancestor of all vehicles. Although the trolley material handling technology continues to evolve, but the trolley is still as indispensable removal tools are still in use. The trolley is widely used in the production and daily life is because of its low cost, simple maintenance, easy operation, light weight, carrying the lighter items in the work of the inconvenient use of motor vehicles, a short distance is very convenient. 

 Trolley (the wheel barrow; barrow; hand truck) to the human push, pull-handling vehicles. It is the ancestor of all vehicles. Although the material handling technology continues to evolve, but the trolley is still as indispensable removal tools are still in use. The trolley widely used in the production and life is because of its low cost, simple maintenance, easy operation, light weight, very convenient when carrying lighter items in the work of the inconvenient use of motor vehicles, a short distance, carrying goods and effort, save time, save money. The trolleys have a single wheel, two, three and four points. The wheelbarrow can be driving in the narrow springboard, the temporary bridge and the narrow winding path, able to pivot turn, dumping of the goods is very convenient. The commonly used two-wheelers carrying into items Hand truck (also known as Tiger car) shelf car, and handling of bulk materials, dump trucks, etc.. Three trolleys, two of the four trolley around the vertical axis of rotation of the rotary caster (see Figure rotary caster). This rotation casters in the running with the change of direction of vehicle motion and automatically adjusts to the running direction of least resistance. 
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 Different purposes of the trolley has a different body structure. The most common four trolleys have a loading platform. Dedicated trolley range structure, some body made of a box, suitable for handling weight is light and easy loading and unloading of goods; some body out of the bay to facilitate the placed rod, shaft and tubes and other parts; some body shape is completely coincide with the goods, such as cylinder wagon; some very small, can be folded, easy to carry; for easy loading and unloading barrels of liquid, scroll to the tubular goods, the body on two flat steel to form a low incline to conducive to tube tilting roll on roll off cargo handling vehicles such as the tubular. Modern trolleys are equipped with bearings, wheels with solid tires or pneumatic tires. Antistatic trolley with stainless steel frame, wire mesh plate, made of steel columns and anti-static nylon wheels, stencil corners cylindrical Department to incorporate a regulator folders and surge tank, light and flexible, steel columns at intervals of one inch recessed groove circle and take over the piece protruding coil with the assembly, can be adjusted according to the desired height and the effective discharge of electrostatic charge characteristics, adjust fast, easy to use. Durable, laminate sub-mesh and plate two types of bridge structure, bearing evenly distributed. Mute trolleys new, beautiful, and the body of synthetic plastic casters use, reduce vehicle weight. Unique mute, transmission design allows the trolley to go silent line, light. Widely used in factory, office buildings, libraries, hotels, catering, logistics and transport and other material handling industry. The trolley according to the different needs, different specifications (for example: there are single, double, hand use, push, etc.), selected when the need according to load weight of the object and the object size, a reasonable choice. The types of trolleys include two-wheeled vehicles and the unicycle, individual rural and mountainous areas in China there are wooden unicycle are still in use today. Wooden unicycle frontline movement of our country's liberation war have played an important role.