Loom
A loom is a device used to weave cloth. The basic purpose of any loom is to hold the warp threads under tension to facilitate the interweaving of the weft threads. The precise shape of the loom and its mechanics may vary, but the basic function is the same.
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Weaving
- See Weaving for more information.
- See Textile manufacturing terminology for more terms connected with looms.
Weaving is done by intersecting the longitudinal threads, the warp, i.e. "that which is thrown across", with the transverse threads, the weft, i.e. "that which is woven".
The major components of the loom are the warp beam, heddles, harnesses, shuttle, reed and takeup roll. In the loom, yarn processing includes shedding, picking, battening and taking-up operations.
- Shedding. Shedding is the raising of the warp yarns to form a shed through which the filling yarn, carried by the shuttle, can be inserted. The shed is the vertical space between the raised and unraised warp yarns. On the modern loom, simple and intricate shedding operations are performed automatically by the heddle or heald frame, also known as a harness. This is a rectangular frame to which a series of wires, called heddles or healds, are attached. The yarns are passed through the eye holes of the heddles, which hang vertically from the harnesses. The weave pattern determines which harness controls which warp yarns, and the number of harnesses used depends on the complexity of the weave. Two common methods of controlling the heddles are dobbies and a Jacquard Head.
- Picking. As the harnesses raise the heddles or healds, which raise the warp yarns, the shed is created. The filling yarn in inserted through the shed by a small carrier device called a shuttle. The shuttle is normally pointed at each end to allow passage through the shed. In a traditional shuttle loom, the filling yarn is wound onto a quill, which in turn is mounted in the shuttle. The filling yarn emerges through a hole in the shuttle as it moves across the loom. A single crossing of the shuttle from one side of the loom to the other is known as a pick. As the shuttle moves back and forth across the shed, it weaves an edge, or selvage, on each side of the fabric to prevent the fabric from raveling.
- Battening. As the shuttle moves across the loom laying down the fill yarn, it also passes through openings in another frame called a reed (which resembles a comb). With each picking operation, the reed presses or battens each filling yarn against the portion of the fabric that has already been formed. The point where the fabric is formed is called the fell. Conventional shuttle 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 the warp beams. To become fully automatic, a loom needs a filling stop motion which will brake the loom, if the weft thread breaks.[1] An automatic loom requires 0.125 hp to 0.5 hp to operate.
Types of loom
Back strap loom
A simple loom which has its roots in ancient civilizations comprising two sticks or bars between which the warps are stretched. One bar is attached to a fixed object and the other to the weaver usually by means of a strap around the back. On traditional looms, the two main sheds are operated by means of a shed roll over which one set of warps pass, and continuous string heddles which encase each of the warps in the other set. The weaver leans back and uses her body weight to tension the loom. To open the shed controlled by the string heddles, the weaver relaxes tension on the warps and raises the heddles. The other shed is usually opened by simply drawing the shed roll toward the weaver. Both simple and complex textiles can be woven on this loom. Width is limited to how far the weaver can reach from side to side to pass the shuttle. Warp faced textiles, often decorated with intricate pick-up patterns woven in complementary and supplementary warp techniques are woven by indigenous peoples today around the world. They produce such things as belts, ponchos bags, hatbands and carrying cloths. Supplementary weft patterning and brocading is practiced in many regions. Balanced weaves are also possible on the backstrap loom. Today, commercially produced backstrap loom kits often include a rigid heddle.
Warp weighted loom
The warp-weighted loom is a vertical loom that originates from Ancient Greece, and spread throughout Europe thereafter.[2] Its defining characteristic is hanging weights (loom weights) which keep the warp thread taut. Frequently, extra warp thread is wound around the weights. When a weaver has reached the bottom of his creation, they can roll the completed section around the top beam, and unwind the extra warp thread from around the weights to continue. This frees the weaver from vertical size constraints.
Tapestry Frame Loom
The tapestry frame loom is the most simple form for a weaving loom. The most simple design for a frame loom is four identical sides. You wrap warp around the frame. This leaves you with warp on both the front and the back of the loom. Or you can use a "warping bar" on which you tie and tie off the warp, giving you the ability to rotate your weaving to the back of the loom as it progresses. Wood was most likely the first material used to make a simple frame loom. The size can vary from very small (would fit in your lap) to very large. The Navajo style loom would be considered a frame loom. Frame looms can also be made of metal. Copper tubing, because it is readily available in hardware stores, is frequently used for such looms. The Archie Brennan loom (so called because Archie, a tapestry weaver and teacher, first came up with this style loom) is made of copper tubing and plumbing fittings. Plans for making this loom are readily available on the internet:
http://www.brennan-maffei.com/Loom.htm
The Mirrix Loom adds bells and whistles to the basic frame loom design by providing feet to stand it upright and a shedding device which allows the weaver to raise alternate sheds rather than having to pick those threads by hand. It, like the Archie loom, has a tensioning device. The Mirrix loom comes in seven different sizes: www.mirrixlooms.com.
Handloom
| Elements of a foot-treadle floor loom |
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The earliest looms were wooden vertical-shaft looms, with the heddles fixed in place in the shaft. The warp threads pass alternately through a heddle and through a space between the heddles (the shed), so that raising the shaft raises half the threads (those passing through the heddles), and lowering the shaft lowers the same threads—the threads passing through the spaces between the heddles remain in place.
Haute lisse and basse lisse looms
Looms used for weaving traditional tapestry are classified as haute lisse looms, where the warp is suspended vertically between two rolls, and the basse lisse looms, where the warp extends horizontally between the rolls.
Power looms
Edmund Cartwright built and patented a power loom in 1785, and it was this that was adopted by the nascent cotton industry in England. A silk loom was made by Jacques Vaucanson in 1745, which used the same ideas but it wasn't developed further. The invention of the flying shuttle by John Kay had been critical to the development of a commercially successful power loom.[3] Cartwright's loom was impractical but the ideas were developed by numerous inventors in the Manchester area in England, where by 1818 there were 32 factories containing 5732 looms.[4]
Horrocks loom was viable but it was the Roberts Loom in 1830 [5] that marked the turning point. Before this time hand looms had out numbered power looms. Incremental changes to the three motions continued to be made. The problems of sizing, stop-motions, consistent take-up and a temple to maintain the width remained. In 1841, Kenworthy and Bullough produced the Lancashire Loom[6] which was self-acting or semi-automatic. This enables a 15-year-old spinner to run six looms at the same time. Incrementally, the Dickinson Loom, and then the Keighley born inventor Northrop working for Draper in Lowell produced the fully automatic Northrop Loom which recharged the shuttle when the pirn was empty. The Draper E and X model became the leading products from 1909 until they were challenged by the different characteristics of synthetic fibres such as rayon.[7]
From 1942 the faster and more efficient shuttleless Sulzer Looms and the rapier looms were introduced.[8] Modern industrial looms can weave at 2000 weft insertions per minute.[9] Today, advances in technology have produced a variety of looms designed to maximize production for specific types of material. The most common of these are air-jet looms and water-jet looms.
Patents
- U.S. Patent 0,000,169 – Loom
See also
- Shuttle (weaving)
- Textile manufacturing
- Timeline of clothing and textiles technology
- Weaving (mythology)
References
- ↑ 1.0 1.1 Collier 1970, p. 104
- ↑ Crowfoot 1936, p. 36
- ↑ Marsden 1892, p. 57
- ↑ Guest, Richard (1823). "The Compendious History of Cotton-Manufacture". pp. 46. http://www.spinningtheweb.org.uk/a_results.php?x=7&y=2&QueryName=KeyWord&KeyWords=Compendious+History. Retrieved Feb 2009.
- ↑ Marsden 1892, p. 76
- ↑ Marsden 1892, p. 94
- ↑ Mass 1990
- ↑ Collier 1970, p. 111
- ↑ S. Rajagopalan, S.S.M. College of Engineering, Komarapalayam, http://www.pdexcil.org/news/40N1002/advances.htm
Bibliography
- Collier, Ann M (1970). A Handbook of Textiles. Pergamon Press. pp. 258. ISBN 0 08 018057 4, 0 08 018056 6.
- Crowfoot, Grace (1936/1937). "Of the Warp-Weighted Loom". The Annual of the British School at Athens 37: 36–47.
- Marsden, Richard (1895). Cotton Weaving: Its Development, Principles, and Practice. George Bell & Sons. pp. 584. http://www.cs.arizona.edu/patterns/weaving/books.html. Retrieved Feb 2009.
- Mass, William (1990). "The Decline of a Technology Leader:Capabilty, strategy and shuttleless Weaving". Business and Economic History. ISSN 089-6825. http://www.h-net.org/~business/bhcweb/publications/BEHprint/v019/p0234-p0244.pdf.
External links
- Loom demonstration video
- "Caring for your loom" article
- "The Art and History of Weaving"
- The Medieval Technology Pages: "The Horizontal Loom"
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