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An Encyclopedia of the History of Technology part 87

An Encyclopedia of the History of Technology part 87. This one of a kind encyclopedia presents the entire field of technology from rudimentary agricultural tools to communication satellites in this first of its kind reference source. Following an introduction that discusses basic tools, devices, and mechanisms, the chapters are grouped into five parts that provide detailed information on materials, power and engineering, transportation, communication and calculation, and technology and society, revealing how different technologies have together evolved to produce enormous changes in the course of history | PART FIVE TECHNOLOGY AND SOCIETY the ring frame has been adapted to spin a greater range of fibres and also to do in one operation the work of two or three earlier roving and spinning machines. In the 1960s it largely replaced the mules in all sections of the textile industry thanks to its greater simplicity and productivity. Open end spinning The ring frame itself began to be replaced during the 1970s by open end or break spinning. The problem with the older ways of spinning has been that the package containing the spun yarn has had to be rotated to put in the twist. The weight increasing as it filled prevented high speeds and limited its size. During the 1950s the Shirley Institute in Manchester experimented with some ways of break spinning but it was not until 1960 that the first commercial open end spinning machine was marketed by the Czechoslovakians. A sliver of fibres is fed to an opening device usually a spiked roller or drum and drawn apart so that the fibres move forward more or less individually. They are carried by an air stream and collected on the inner surface of a cup-shaped rotor with a hole in the end which revolves at 30 000-60 000rpm. During each revolution a thin layer of fibres is deposited in a collecting groove on the inner surface of the cup. Layers of fibres are laid one upon another until a strand is built up. This is peeled from the groove and twisted by the rotor as it is drawn out of the hole in the end. From here the strand or yarn is wound on to a bobbin. Open end spinning has a very high rate of production and has been developed to give a fine quality yarn with some of the characteristics of that spun on the mule. In 1964 the Repco self-twist spinning machine was patented. A pair of rovings is drawn out and passed through aprons which are moved from side to side to give a false twist. The twist lies alternately in opposite directions and would soon untwist itself but while one roving moves straight forward the other goes round .