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Loom
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A loom is a machine or device for weaving thread or yarn into textiles. Looms can range from very small hand-held frames, to large free-standing hand looms, to huge automatic mechanical devices. The ancient Egyptians and Chinese used looms as early as 4000 BC.
In practice, the basic purpose of any loom is to hold the warp threads under tension to facilitate the interweaving of the weft threads.
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Encyclopedia
A loom is a machine or device for weaving thread or yarn into textiles. Looms can range from very small hand-held frames, to large free-standing hand looms, to huge automatic mechanical devices. The ancient Egyptians and Chinese used looms as early as 4000 BC.
In practice, 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.
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".
Types of looms
Handloom
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- Wood frame
- Seat for weaver
- Warp beam- let off
- Warp threads
- Back beam or platen
- Rods – used to make a shed
- Heddle frame - heald frame - harness
- Heddle- heald - the eye
- Shuttle with weft yarn
- Shed
- Completed fabric
- Breast beam
- Batten with reed comb
- Batten adjustment
- Lathe
- Treadles
- Cloth roll- takeup
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The earliest looms were vertical shaft, with the heddles fixed in place in the shaft. The warp threads pass alternately through a heddle and through a space between the heddles, so that raising the shaft will raise half the threads (those passing through the heddles), and lowering the shaft will lower 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. A silk loom was made by Jacques Vaucanson in 1745, which used the same ideas but it wasn't developed further.Powered looms were shuttle-operated for two hundred years. 200 Austin looms (under license) were installed in a Pollockshaw mill in 1800. The 1803 Johnson improvements in warping led to a new power loom factory in Manchester in 1806, and three more factories in Stockport and Wigan by 1810. By 1818 there were 32 factories containing 5732 looms..
In the early part of the 20th century the faster and more efficient shuttleless rapier looms and air looms came into use. Modern industrial looms can weave at speeds 2000 Weft insertions per minute. 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.
Shuttle looms
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 if formed is called the fell. Conventional shuttle looms can operate at speeds of about 150 to 160 picks per minute.
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. An automatic loom requires 0.125hp to 0.5hp to operate.
Knitting looms
Knitting looms (also known as Amish looms or knitting boards) were recently popularized in crafting circles by the Knifty Knitter system. Knitting looms are a descendant of the frame loom. Grooved pegs are spaced along a central frame. These pegs are wrapped with yarn in various ways, then the knitter uses an angled hook to pull the wrapped yarn over the top of the peg, resulting in a fabric with stitches similar to a needle knitted item.
Bow Looms
A type of loom used for thin strips of beading. A bow loom consists of a bendable branch of cedar, willow or other easily bendable types of wood. 10-11 holes are then made along the length of two smaller pieces of wood. Thread is looped through the holes and attached to the long bendable piece. Once the bow is threaded, the thread is then used for beading. This method was traditionally used by the Native Americans.
Patents
See also
Bibliography
External links
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