Sholes and Glidden typewriter seeking to diversify, Remington further refined the typewriter before finally placing it on the market on July 1, 1874. During its development, the typewriter evolved from a crude curiosity into a practical device, the basic form of which became the industry standard. The machine incorporated elements which became fundamental to typewriter design, including a cylindrical platen and a four-rowed QWERTY keyboard. Several design deficiencies remained, however. The Sholes and Glidden could print only upper-case letters—an issue remedied in its successor, the Remington No. 2—and was a "blind writer", meaning the typist could not see what was being written as it
Roller chain Roller chain Roller chain or bush roller chain is the type of chain drive most commonly used for transmission of mechanical power on many kinds of domestic, industrial and agricultural machinery, including conveyors, wire- and tube-drawing machines, printing presses, cars, motorcycles, and bicycles. It consists of a series of short cylindrical rollers held together by side links. It is driven by a toothed wheel called a sprocket. It is a simple, reliable, and efficient means of power transmission. Though Hans Renold is credited with inventing the roller chain in 1880, sketches by Leonardo da Vinci in the 16th century show