Saturday, July 9, 2011

Inventions: Bicycle

The name Bicycle dates from 1869. Various precursors of it were known as velocipedes, from a French name dating from the late 18th century. Basic two-wheeled vehicles driven by the feet were popular as early as the second half of the 17th century. In 1690 a Frenchman invented the celerifere, consisting of a wooden beam to which the wheels were affixed. The vehicle had no handlebar, the rider sat on a cushion on the beam and propelled and steered the machine by pushing his or her feet against the ground. In 1816 a German nobleman designed the first two-wheeled vehicle with a steering device. This machine was named the Draisine after the inventor’s name. It had a handlebar that pivoted on the frame, enabling the front wheel to be turned. In England these early models were known as hobby horses; the name dandy horse was applied particularly to the expensive pedestrian curricle, invented in 1818. The curricle was lighter in weight than the Draisine and had an adjustable saddle and elbow rest. It was patented in the United States in 1819. In 1839 driving levers and pedals were added to a machine of the Draisine type by Kirkpatrick Macmillan of Scotland. These innovations enabled the rider to drive the vehicle with the feet off the ground. The driving mechanism consisted of short cranks fixed to the rear wheel hub and connected by rods to long levers, which were hinged to the frame close to the head of the machine. The connecting rods were joined to the levers at about one-third of their length from the pedals. The machine was propelled by a downward and forward thrust of the foot. In 1846 an improved model of this machine, designed by a Scotsman, acquired the name Dalsell and was widely used in England.
The direct precursor of the modern bicycle was the French crank-driven, loose-pedaled velocipede, which became popular in France about 1855. The frame and wheels were made of wood. The tires were iron, and the pedals were attached to the hub of the front, or driver, wheel, which was slightly higher than the rear wheel. In England this machine was known as the Boneshaker, because of its effect on a rider pedaling over a rough road or a cobblestoned street. In 1869 in England, solid rubber tires mounted on steel rims were introduced in a new machine, which was the first to be patented under the modern name Bicycle.
The modifications and improvements of the next 15 years included the ball bearing and the pneumatic tire. These inventions, along with the use of weld less steel tubing and spring seats, brought the ordinary bicycle to its highest point of development. The excessive vibration and instability of the high-wheel bicycle, however, caused inventors to turn their attention to reducing the height of the bicycle.

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