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  Power loom Some of the 1200 power looms at the  Plevna factory building, completed in 1877, at theFinlayson & Co cotton millsinTampere,Finland. A Northrop loom manufactured byDraper Corporationin the textile museum,Lowell, Massachusetts.The first power loom , a mechanizedloompowered by adrive shaft,was designed in 1784 by Edmund Cartwrightand first built in 1785, it was refined over the next 47 years till a design byKenworthy and Bullough, made the operation completely automatic. This was known as theLancashire Loom By 1850 there were 250,000 machines in operation in England. Fifty yearslater came the Northrop Loomthat would replenish the shuttle when it was empty and thisreplaced the Lancashire loom. Shuttle looms Draper power loom in Lowell, Mass. US The major components of the loom are the warp beam, heddles, harnesses,shuttle,reedand takeup roll. In the loom, yarn processing includes shedding, picking, battening and taking-upoperations.  ã Shedding . Shedding is the raising of thewarpyarns to form ashedthrough which the filling yarn, carried by the shuttle, can be inserted. The shed is thevertical space between the raised and unraised warp yarns. On the modernloom, simple and intricate shedding operations are performed automaticallyby the heddle or heald frame, also known as a harness. This is a rectangularframe to which a series of wires, called heddles or healds, are attached. Theyarns are passed through the eye holes of the heddles, which hang verticallyfrom the harnesses. The weave pattern determines which harness controlswhich warp yarns, and the number of harnesses used depends on thecomplexity of the weave. Two common methods of controlling the heddlesaredobbiesand a Jacquard Head. ã Picking . As the harnesses raise theheddlesor healds, which raise the warpyarns, the shed is created. The filling yarn in inserted through the shed by asmall carrier device called a shuttle. The shuttle is normally pointed at eachend to allow passage through the shed. In a traditional shuttle loom, thefilling yarn is wound onto a quill, which in turn is mounted in the shuttle. Thefilling yarn emerges through a hole in the shuttle as it moves across theloom. A single crossing of the shuttle from one side of the loom to the other isknown as a pick. As the shuttle moves back and forth across the shed, itweaves an edge, or selvage, on each side of the fabric to prevent the fabricfrom raveling. ã Battening . As the shuttle moves across the loom laying down the fill yarn, italso passes through openings in another frame called areed(whichresembles a comb). With each picking operation, the reed presses or battenseach filling yarn against the portion of the fabric that has already beenformed. The point where the fabric is formed is called the fell. Conventionalshuttle looms can operate at speeds of about 150 to 160 picks per minute. [1] With each weaving operation, the newly constructed fabric must be wound on a cloth beam. This process is called taking up. At the same time, the warp yarns must be let off or released from thewarp beams. To become fully automatic, a loom needs a filling stop motion which will brake theloom, if the weft thread breaks. [2] For all this to happen, the yarn has to be prepared. The weft, or filling must be wound tightly onthe correct size pirns, quills or bobbins. Weaving happens at great speed so the yarn must be atthe correct tension when it leaves the shuttle. The warp passes through the heddles which stretchit at each pick, and through the reeds which are abrasive. The warp is thus sized, that is coatedwith a mixture that can include china clay and flour, to give it extra strength and to act as alubricant. It is dressed or wetted while passing through the loom. The warp, hundreds of ends of yarn rolled in parallel, comes on a wooden beam. Before weaving can commence each end must be passed through the heddles and reeds: a process known as looming. [3] An automatic loom requires 0.125hp to 0.5hp to operate.
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