Weaving.—A woven fabric consists of threads which run lengthwise, called the “warp,” crossed by threads running transversely, called the “woof,” “weft,” or “filling,” which latter are imprisoned or locked in by the warp. In a simple loom the warp threads are divided into two groups, the threads of one group alternating with those of the other, and means are provided for separating these groups to form a wedge-shaped space between them called a “shed.” Through this shed the shuttle which carries the woof or filling thread is sent crosswise the warp threads. Means are provided for changing the inclination and position of the two groups of warp threads in relation to each other, so as to lock in the filling, and put the warp threads in position to receive the next filling thread. For this purpose the warp threads, usually horizontal, are each passed through a loop, and every alternate loop is attached to a frame called a “heddle.” The intervening loops and threads are attached to another frame or “heddle,” and the two heddles by being worked, one up and the other down, separate the warp threads to form the shed. Formerly the shuttle was thrown by hand through the shed. In 1733 John Kay, of England, took out British patent No. 542, for the flying shuttle and picking stick, by which the shuttle was struck a hammer-like blow and driven like a ball from a bat across the warp, and was struck by a similar stick on the other side, to be returned in the same way. This gave a much more rapid action than could be obtained by hand-throwing, and enabled one weaver to do the work of two or three. In 1760 Robert Kay invented the drop box, by which different shuttles carrying different colors of thread were employed.
The power loom, however, marked the first great growth in the art of weaving. The enormously increased quantity of cotton spun by Arkwright’s machinery made a demand for increased facilities for weaving it into cloth. Dr. Cartwright, of England, foresaw and met this demand in his power loom, in which all of the intricate operations were performed by power-driven machinery. His invention was not extensively introduced until about the beginning of the Nineteenth Century. One difficulty experienced was that the warp threads, from their fuzzy nature, had to be dressed with size, and this required the loom to be stopped from time to time, and necessitated the services of a man to dress or size the warp threads. This difficulty was overcome, however, by Johnson & Radcliffe, about 1803, by the sizing and dressing of the yarns by passing them between rollers and coating them with a thin layer of paste before being put into the loom. Dr. Cartwright was granted British patents No. 1,470, of 1785; No. 1,565, of 1786; No. 1,616, of 1787, and No. 1,676, of 1788, but being unable to maintain any monopoly under his patents he was compensated by Parliament with a grant of £10,000.
FIG. 290.—MODERN JACQUARD LOOM.
Jacquard Loom.—This most notable step in the art of weaving was made at the very beginning of the Nineteenth Century. It enabled all kinds of fabrics, from the finest to the coarsest, to be cheaply woven into patterns having figured or ornamental designs. Jacquard, a native of Lyons, conceived the plan of his great invention in the last decade of the Eighteenth Century, and on December 28, 1801, took out French patent No. 245, on the same. His invention was not, in fact, a new form of loom, but rather an attachment to a loom which was universally applicable to all looms. Before his invention, figured patterns of cloth could only be made by slow and laborious processes. Jacquard’s invention consisted in individualizing and differentiating the movement of the warp threads, instead of operating them in constant groups. This individualizing of the movement of the warp threads allowed any warp thread to be held up automatically any length of time, or let down, according as was necessary to form the figure of the pattern. This was accomplished by making a chain of articulated cards, like a slatted belt, and perforating these cards with varying arrangements of holes. The cards were successively and intermittently fed to a set of needles, which latter, by rising and falling, raise or lower the warp threads attached to the same. By perforating these cards differently, and arranging them so that when one card was brought in front of the needles it would let certain needles through the perforations and hold the others back, it will be seen that each card controlled the action of a different set of needles, and the sequence of the series of cards effected the necessary change in the needles and movement of the warp threads to form the growth of the figure in the fabric.
In [Fig. 290] is seen a modern form of Jacquard loom, showing at the far end the chain of perforated cards. Jacquard received a bronze medal at the French Exposition in 1801, was decorated with the Cross of the Legion of Honor, and the gratitude of his countrymen was attested by a pension of 6,000 francs, and a statue erected to his memory at Lyons in 1840.
Subsequent improvements and developments of the Jacquard loom have carried its work to great nicety and refinement of action. In the chain of pattern cards it is said that as many as 25,000 separately punched cards or plates are sometimes used in weaving a single yard of brocade. The great variety of elaborate designs of delicate tracery in silk, rich patterns in brocades, and gorgeous figures in carpets, attest the value of Jacquard’s important step in this art.
Nearly 5,000 United States patents have been granted in the class of weaving. In the early part of the century much notable work was done. Steam was applied to looms by William Horrocks (British patent No. 2,699, 1803). From 1830 to 1842 there were brought out the fancy looms of Crompton, the application of the Jacquard mechanism to the lace frame by Draper, and the carpet looms of Bigelow. In 1853 Bonelli sought to improve on the Jacquard mechanism by employing electro-magnets to effect the selection of the needles, instead of perforated cards (British patent No. 1,892, of 1853).
Among more recent developments is the Positive Motion loom of Lyall, patented December 10, 1872, No. 133,868, re-issue No. 9,049, January 20, 1880. The distinguishing feature of this is that the shuttle is not thrown or impelled as a projectile through the wedge-shaped space (shed), between the two sets of warp threads, but is positively dragged back and forth through the same by an endless belt attached to the shuttle carriage and running first in one direction and then in the other to drag the shuttle through.