LOOMS, are machines for crossing and weaving threads. The two materiels are the warp and the weft, crossed and matted by a shuttle carrying the weft. There are various forms for different fabrics and ma terials, and next to the plough the loom is the most useful of machines. Until a few years they were uniformly worked by hand.
The power loom has now, however, for most descriptions of weaving, almost en tirely superseded the hand loom.
The principal working parts are snb stmtieliy the same in the power loom, as in the hand ifmni. The only material difference being, that in the Innid loom, the parts have all t heir movements given by the hands and feet of the weilver, while in the power loom, they all fteei ye the necessary motion from a revolving shaft.
The warp threads, or the threads which run lengthwise in the cloth, are led from a roller, termed the yarn beam, through what is termed a reed. The reed consists of a number of wires, secured in a frame, which is supported in a swinging or vibrating carriage, termed the lay. The wires of the reed, serve to keep the warp threads apart, and to beat up the weft, (afterwards described). From the reed,the warp passes over a bar termed the breast beam, to a roller, termed the cloth beam. All that part of the warp, between the yarn beam and the breast beam, is kept straight, except while the warp is being filled in. The weft is carried by the shuttle, which consists of a piece of wood, pointed at each. end, and hol lowed out in the middle to receive a reel, termed the bobbin. The thread is wound around the bobbin, and passed through a hole in one side of the shuttle. In weav
ing figured goods, where different colors are displayed, a number of shuttles are employed, corresponding to the number of colors. In order to throw the shuttle or pass it, with the weft, through the warp, it is necessary to raise some of the warp threads, and depress others ; this is termed opening the shed, and is per formed by the harness. The harness eon-' silts of boards or frames having looped cords attached, termed peddles. The warp passes through the heddlcs, and by raising and lowering the harness, the sheds are opened. In the hand loom, the harness is operated by treadles, worked by the pressure of the weavers' feet, but in power looms, it is operated by various means. In the hand loom, the shuttle is passed through the warp by hand • but in the power loom, it rests upon a path in front of the reed, and is thrown be me chanical means. The thread unwinds from the bobbin, and remains in the warp, and the lay, receiving a movement after every throw of the shuttle, causes the reed to strike up all the threads of the weft, close together, and lay them even. By the continued opening and closing of the sheds of the warp, filling in, and striking up of the weft, the threads are interlaced closely together. The cloth beam, end yarn beam, each receive a slight motion after every filling- of the weft. These are governed by take up and let off, motions. For more information, see WEAVING.