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  • Steering wheel


    Passenger car steering wheels from different periods Steering wheel and front wheels of a farm tractor Steering wheel in a VDL Bova bus A steering wheel (also called a driving wheel or a hand wheel) is a type of steering control in vehicles and vessels (ships and boats). Steering wheels are used in most modern land vehicles, including all mass-production automobiles, as well as buses, light and heavy trucks, and tractors. The steering wheel is the part of the steering system that is manipulated by the driver; the rest of the steering system responds to such driver inputs. This can be through direct mechanical contact as in recirculating ball or rack and pinion steering gears, without or with the assistance of hydraulic power steering, HPS, or as in some modern production cars with the assistance of computer-controlled motors, known as Electric Power Steering.

  • Wheelbarrow


    A common wheelbarrow. Older wheelbarrow A wheelbarrow is a small hand-propelled vehicle, usually with just one wheel, designed to be pushed and guided by a single person using two handles at the rear, or by a sail to push the ancient wheelbarrow by wind. The term "wheelbarrow" is made of two words: "wheel" and "barrow." "Barrow" is a derivation of the Old English "bearwe" which was a device used for carrying loads. The wheelbarrow is designed to distribute the weight of its load between the wheel and the operator, so enabling the convenient carriage of heavier and bulkier loads than would be possible were the weight carried entirely by the operator. As such it is a second-class lever. Traditional Chinese wheelbarrows, however, had a central wheel supporting the whole load. Use of wheelbarrows is common in the construction industry and in gardening. Typical capacity is approximately 100 liters (4 cubic feet) of material. A two-wheel type is more stable on level ground, while the almost universal one-wheel type has better maneuverability in small spaces, on planks, in water, or when tilted ground would throw the load off balance. The use of one wheel also permits greater control of the deposition of the load upon emptying.

  • History of watches


    Portable drum watch with sundialThe 24-hour dial is marked in Roman numerals on the outer band and in Arabic numerals on the inner one The history of watches began in 16th century Europe, where watches evolved from portable spring-driven clocks, which first appeared in the 15th century. The watch which developed from the 16th century to the mid 20th century was a mechanical device, powered by winding a mainspring which turned gears and then moved the hands, and kept time with a rotating balance wheel. The invention of the quartz watch in the 1960s, which ran on electricity and kept time with a vibrating quartz crystal, proved a radical departure for the industry. During the 1980s quartz watches took over the market from mechanical watches, an event referred to as the "quartz crisis". Although mechanical watches still sell at the high end of the market, the vast majority of watches now have quartz movements. One account of the origin of the word "watch" is that it came from the Old English word woecce which meant "watchman", because it was used by town watchmen to keep track of their shifts.

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