Читать книгу Jacquard Weaving and Designing - T. F. Bell - Страница 8

Table of Contents

This machine was introduced by Mr. Thomas Morton, of Kilmarnock. The harness and tail or knot cords are arranged similarly to those in the comb draw loom; but instead of the simple cords for drawing out the tail cords, each tail cord in the barrel loom passes through a slide, or horizontal wire. The points of these slides are acted upon by the pattern cylinder or barrel, and those held back press out their tail cords from the others, and the knots on these tail cords are caught by the teeth on the comb or roller, and the harness raised.

The pattern is arranged upon the barrel much in the same way as a tune is arranged on the cylinder of a barrel organ or musical box. A section of the barrel is shown at A (Fig. 10), with wire staples driven into it to form the pattern.

Fig. 10

Each of these staples represents so many lines of the design paper, or so many lashes or draughts. The pattern is ruled out and painted on the barrel, and staples are driven into it so as to cover the painted squares of the pattern. The barrel is so arranged on the loom that exactly the space of one line of the design paper is turned round for each draught, and the slides are drawn back by cords attached from their ends to a roller when the shift of the barrel is being made. B is a section of the comb; it is a cylinder with teeth, C, like a parrot’s beak fixed to it. The teeth are made of this shape to hold the knot cords when they are caught by them, and they rise or fall as the roller is rocked upwards or downwards by a treadle.

Whilst these improvements on the draw loom were being made in this country for the purpose of producing a convenient method of harness weaving, the French were endeavouring to obtain the same result, but on a different principle, and their method has proved successful.

In 1725 M. Bouchon employed a band of pierced paper, pressed by hand against a row of horizontal needles, so as to push back those which were opposite the blank spaces, and thus bring loops on the extremities of vertical wires into connection with a comb-like rack below, which, being depressed, drew down the wires, pushed on the pins in it, and raised the harness.

Fig. 11

Fig. 11 is a sketch of a model of this loom in the Conservatoire des Arts, Paris. A is the pulley-box with two rows of pulleys in it; B the tail cords; C the simples, tied to rings on their upper ends, which run on the tail cords at B; the other ends of the simples pass over a small roller at D to prevent them rubbing against the side of the loom, then down through the hole board F, under which they are tied to wire hooks or loops, as shown under A (Fig. 11a). Next these wires pass through the needle box G, also shown at B, Fig. 11a, and down to the comb H (Fig. 11), and C (Fig. 11a). The perforated paper is rolled on the roller E, and passing downwards, is pressed against the needles with a hand bar, as shown at L, Fig. 11b. The roller K is for rolling up the paper as it passes down from the upper roller.

Fig. 11b is a back view of the mounting. A shows where the simples are connected with the tail cords P; B shows the connection of the tail cords with the harness; C is the cumber board; D the mails and E the leads. F and K are the two rollers for the paper, H the needle box, and I the comb. This was the first attempt at forming the pattern by means of perforated paper acting upon needles and wires.

In 1728 M. Falcon adopted a chain of perforated cards in lieu of the perforated paper, and placed his horizontal wires or needles in several rows or ranks, thereby admitting the use of a greater number of them in a moderate space. He also used a square prism or cylinder, as it is called, for the cards to pass over.

Fig. 11a

Fig. 11b

Fig. 12 is a sketch from a model of his loom, also in the Conservatoire des Arts. The principle of it is much the same as the preceding. A is the pulley box for four rows of pulleys, B the connection of the simple with the tail cords, C the hole board for the simple to pass through and also the support for the cylinder H, D is the needle box, E the comb or griffe, F the levers for drawing down the griffe, and G the treadle. The cards are laced in a chain and pass over the cylinders I and H, but they are pressed against the needles by a hand bar, similar to that used by Bouchon. There are two racks or receptacles for holding the cards, as shown. The cylinders H and I are simply used as rollers to support the cards, and not for pressing them against the needles, as in the jacquard.

Fig. 12

Figs. 12a and 12b give detailed views of the hooks, etc., for drawing the harness: the letters in both refer to the same parts as are marked with similar letters in Fig. 12. The simples B are tied to loops on the hooks under the hole board C. In Fig. 12b it will be clearly seen how the needles in four rows act upon the hooks. The griffe consists of four round iron rods or wires set in the frame E, Fig. 12a, which can be drawn down by the treadle G, connected with the levers F by the cords 3 and 4. One of the levers has its fulcrum at one side and the other has it at the opposite side, and the points of the levers are tied to the griffe frame by the cords 1 and 2. The griffe, when sunk, is brought back to its place again by weights hanging on cords running over pulleys. It may be seen that the hooks hang in front of the rods or bars of the griffe; therefore, those hooks will be pushed on the griffe whose needles come against the solid portions of the cards, thus acting similarly to Bouchon’s machine. The hand bar for pressing the cards against the needles is shown at F. The needles can pass through the slot in it, and, when a card is pressed against the needles, the bar can be fastened with hooks for the purpose, so that the operator is free to depress the treadle. There are no springs on the needles, but a clap board comes behind them, which is pressed in by means of a cord passing over each end of it and fastened to a spiral spring. There are ten leaves of heddles in front of the harness. They are plain clasped heddles, and apparently act as five, the front five being raised by the top levers connected with the treadles, as shown in Fig. 11, and the back five are held up by a set of levers at each side, with weights on the ends of them, similarly to those now used for hand-loom damasks, and tied to the treadles below, so that sinking a treadle would cause one of the back leaves to sink and one of the front ones to rise. Only the harness mechanism of Falcon’s loom is given in Fig. 12, the front portion being similar to that of Bouchon, or to any hand loom.

Fig. 12a

Fig. 12b

In 1746 the accomplished mechanician, Vaucanson, altogether dispensed with the cumbrous tail cords and simple of the draw loom, and made the draw-boy machine completely self-acting by placing the hooks upright on the top of the loom, and hanging the harness from them. This loom may be seen in the Conservatoire des Arts, as well as a model of it on the same scale as those already mentioned—viz., one-third the size. The machine for drawing the harness is exactly like a small jacquard, with two rows of hooks and two rows of needles, as shown in Fig. 13. Instead of a square cylinder and cards, the pattern is punched on a band of paper, which passes over a round or true cylinder. This cylinder is fitted with a rack wheel, so that a tooth can be passed for each change of pattern, the cylinder moving out and turning one tooth, then pressing in against the cards again. The diameter of the cylinder is about twelve inches. The hooks are raised with a griffe, similar to that in a jacquard, which is fastened to a lever connected to a treadle below. This treadle, and four others for working the heddles, is wrought by tappets, made of wood, on a shaft running along the side of the loom and turned by a wince handle in front. Altogether, the loom is a nice mechanical contrivance, and a great step in advance of its predecessors.

Fig. 13

Joseph Marie Jacquard, a working mechanic of Lyons, having invented a fishing net loom, turned his attention to improving the means of drawing the harness in looms for figured weaving, about 1790. A model of a machine by him, dated 1790, to dispense with the drawing of the harness, is in the Conservatoire des Arts. It is made with cords and rollers, and has no resemblance to the machine bearing his name. He was brought to Paris to repair Vaucanson’s loom about 1804, and it appears to be then that he combined the best qualities of the machines of his predecessors, and produced the jacquard, a model of which, dated 1804, is in the Conservatoire des Arts. This is very much like our present jacquard, but with four rows of hooks and needles made similar to those of Vaucanson, Fig. 13. He dispensed with Vaucanson’s cylinder and band of paper, and used instead a square prism with a chain of cards passing over it. The cylinder (or prism) he set in a frame or carriage, made to run on four wheels or pulleys on the top of the frame of the loom. The carriage is drawn out by depressing a treadle, and brought back again to press the cylinder against the needles, by means of weights tied to cords running over pulleys. The griffe is raised by means of two levers, one at each side; one end of each is connected with the griffe, and the others to a crossbar at the bottom of the loom, and this crossbar is fastened from its centre to a treadle. In all these looms the cards or paper hang at the side of the loom, the mounting being on the principle known as the London tie. Jacquard was born in 1752, and died in 1834. Vaucanson died in 1782.