Cotton Weaving and Designing / 6th Edition

by John T. Taylor

THE LENO JACQUARD.

FIG. 144.

Where figures are required to be thrown up on a leno ground a Jacquard mounting is required. It is possible to weave a plain figure on a gauze ground with an ordinary Jacquard harness and an ordinary doup stave in front, but this can only be done on a pure gauze ground—that is, one end crossing one. A plain figure on a ground of this kind does not afford a sufficiently powerful contrast to the ground. It is necessary in order to produce a really efficient contrast to have two ends crossing two and weaving separately in the plain. A fabric of this kind is one of the most beautiful of all fabrics, and is remarkably cheap and serviceable in wear. The method of producing a plain figure on a gauze ground with one doup in front of any ordinary Jacquard harness is illustrated at [Fig. 144]. The ends are drawn through the Jacquard as usual, and are then taken in pairs and one crossed under the other, the crossing end being taken through the doup, as shown in the diagram. The crossing end in each pair is marked A. We can now see how either plain or gauze can be woven at will. The doup is lifted for the first pick, and this brings all the ends A up at the right hand side of ends B (see first pick). In the first two dents the ends A are lifted again by the harness, and the loose half of the doup being lifted will enable the ends A to cross to the left side of the ends B. The doup is lifted for the third pick, and it is obvious that this will weave gauze with the first two dents. After the doup is lifted, if the end B is lifted on the next pick, it will cause plain to be woven, as will be seen from the diagram, where the third and fourth dents are weaving plain when the first and second dents are weaving gauze, and vice versâ.

FIG. 145.

FIG. 146.

A proper leno harness is illustrated at [Fig. 145]. It is obviously impossible with the arrangement given at [Fig. 144] to weave a leno with two ends crossing two in conjunction with plain, as there would require to be two ends in each eye in the doup, and as the doup is lifted every other pick, it is impossible to change to plain from the leno. To obtain a figured leno of this description, each dent must have a doup to itself, and the doups must be lifted by the hooks. At [Fig. 145] the arrangement of the harness is shown. The machine is a single lift, and in order to obtain a 400 end figure 600 hooks are required. These are arranged in twelve rows, the two front rows being used for the doup harness, the two back rows for the slackening harness, and the eight middle rows for the ground or figure harness. For the 600 hooks only 500 needles are used, the doup hook and its slackening hook being connected with the same needle. The top and bottom needles are used for the doups and slackeners, as shown in the diagram, and the eight middle rows of needles for the ground or figure harness. The method of drawing the warp through the harness is shown at [Fig. 146]. The two crossing ends are drawn through the slackening harness, and all the ends are drawn through the ground harness. It is immaterial whether the draft is from back to front or front to back; some manufacturers of these goods draw the ends from front to back. Of course, this must be borne in mind in designing and cutting the cards. After being drawn through the ground harness the two crossing ends are crossed under the other two and drawn through a doup. The mails in the doup lingoes are specially made to allow the thread from the slip to pass through and back again. The shaft A ([Fig. 145]) is the slip or loose half, and serves for all the doups. The mails in the slackening harness are placed, lower down than the other warp, and these mails hang between two rods, B and C, which are called the “bridge.” Sometimes only one rod is used, and this serves equally well.

A better shed is formed by only lifting the slackening hooks half as much as the other hooks, and therefore a special device is required for giving only half the lift to these hooks. In the illustration, [Fig. 145], there are two griffes, E and H, and the griffe E is connected to the lever GK at a point, O, about midway between the fulcrum G and the point where the griffe H is connected to the lever. The fulcrum G is movable in a slot made for that purpose, so that the lift of E can be altered a little if desired. When the griffe H is lifted in the ordinary manner, it is obvious that the griffe E will only be lifted about half way.

FIG. 147.

The usual method of obtaining the half-lift, which this invention is intended to supplant, is illustrated at [Fig. 147]. This method was invented by the late Mr. Tootal Broadhurst, and has been in regular use a long time. Each of the slackening hooks lifts a lever CP, centred at C, the slackening harness is tied to these levers about midway between C and P, and thus the mails are lifted only about half as much as the hooks. Of course, in this case all the hooks in the machine are lifted by one griffe, and therefore the slackening hooks are lifted as far as the others.

This method serves its purpose very well, but if any alteration is required in the lift of the slackening harness all the levers have to be gone through and altered separately, whereas in the Devoge machine the lift can be regulated to a nicety by moving the fulcrum G and the point O. The slackening harness should be placed from nine inches to a foot behind the ground harness.

The wire M, in [Fig. 145], is for lifting the shaft A, which is required to be lifted every pick. The advantage of using only one needle for the doup and slackening hooks is that it prevents the possibility of the slackener being missed when the doup lifts, as well as being a saving in cards.

By lifting the crossing ends with the ground harness for two or more picks, followed by lifting the same ends in the doup harness for a similar number of picks, an open leno fabric is produced, and a plain figure can be woven by lifting the ground harness plain, or a floated figure can be formed exactly as with an ordinary Jacquard.

FIG. 148.

FIG. 149.

The usual method of putting the design on point paper for these Jacquards is illustrated at [Fig. 148]. In the plan eight ends of leno are shown with four picks in a shed; and eight ends of plain, of which the figure is usually formed, are shown. The design on point paper for this would be as given in [Fig. 149]. Ordinary 8 × 8 paper is used, although there are ten rows of needles. The card-cutter cuts the black squares opposite the ground harness needle, and where the circles come, he cuts so as to lift the doup in the next dent. Thus in the first four cards for [Fig. 149], the card-cutter would cut opposite the third and fourth needles in the ground harness, and opposite the doup needle for the next four ends. The plain would be cut in the ordinary manner opposite the ground harness needles. A larger design for this harness will be found in Chapter X.

Double-lift Jacquards are not yet used beyond the experimental form, as the shaking cannot be done as easily as in a dobby with shafts, but we have heard of the thing being done by knotting the harness above the comber board and lifting the board a little when the cross is being made. Messrs. Eccles, of Preston, some years ago obtained a patent for lifting the standard ends by means of a third knife or griffe. The additional knife was given half the lift of the other two, and its function was to lift the standard ends half way when the doup ends were crossing to the other side. This would, no doubt, enable the cross to be made with ease in a double-lift Jacquard, but the principle is not likely to be a great success.

The doups in leno Jacquards are very liable to wear out unless made of very good material, and some experience is necessary before the harnesses are worked satisfactorily.

An imitation of the fabric usually woven on this harness is sometimes made by making one end cross three ends in the leno, and weave plain in the figure. This can be done with an ordinary harness with a doup heald in front lifted every other pick, on the same principle as in [Fig. 144].

CHAPTER VIII
TERRY LOOMS—CARD CUTTING—LAPPETS

FIG. 150.

TERRY looms are extensively used in the cotton trade, chiefly for weaving towels, but often for striped dress and similar fabrics where terry or loop pile is combined with other weaves. The loops can be formed either on one side or both sides of the fabric, but the loop formed in these looms is not to be compared with real loop pile woven over wires, as the loops cannot be formed with the same regularity. There are numerous terry motions, as they are called, most loom makers having their own speciality. [Fig. 150] is the design for a good terry cloth. It will be noticed that the second and fourth ends are the reverse of each other: one is up for four picks and down for one, and the other is down for four picks and up for one, whilst the other two ends are nearly plain. The first and third ends form the ground, and the second and fourth ends the pile or loops. There are five picks to the round.

FIG. 151.

FIG. 152.

The ground warp is on a separate beam to the pile warp, the latter having a special tension to let off the required quantity to form the pile. At the second pick in the pattern, just where the pile warp is bound, the reed is made to beat further up than on the two preceding picks, thus forming a pile by sending one half the pile ends to the face and the other half to the back. The reed beats up to the front for the second, third, and fourth picks in the pattern, as given at [Fig. 150], following which the reed is held back for two picks. [Fig. 151] is a good motion for making the reed occupy the two positions when beating up. P represents the slay, and a lever, A, centred at D, is so constructed that when A is pulled down the reed is pushed forward. The rod R is connected to a lever, M, on a shaft, N, placed under the loom. A rocking motion is given to this shaft by a box cam, P, five to the round ([Fig. 152]), so shaped as to lift and depress the lever QS for the required number of picks. This cam is driven from the picking shaft. By pulling the rod R downwards the reed is moved forwards, and the rod will have to be kept down for three picks and moved up for two picks, so as to keep the reed in its front position for three picks and a little way back for two. The effect required is really to lengthen the crank-arm at will, and the principle of the knuckle joint may be used in its simplest form—that is, by having the crank-arm jointed in the middle and fixed a little out of a straight line, and by straightening the arm when the front position of the slay is required.

The real loop pile is woven over wires. The wires can be inserted and pulled out automatically by a power-loom, but the richest kind of pile is woven on the hand-loom. The structure of the fabric is shown at [Fig. 153]. The pile end is brought up over a wire every two picks, and when the wire is pulled out the loops form a springy pile, which can be made to give beautiful effects in dress goods. The principle is also used in Brussels carpets, and similar goods. Where figured fabrics are required on this principle, it is necessary to have each pile end on a separate bobbin and weighted separately at the back of the loom, as the take-up of each end would vary so much in the figure.

FIG. 153.

FIG. 154.

With cut pile the wires are either grooved, as at [Fig. 154], or each wire has a knife at the end, as at [Fig. 155], and when the wire is pulled out it cuts the pile. The best pile is formed by the grooved wires, as the cutting wires are apt to drag the pile. When cut pile is being made, about four or five wires are constantly in the cloth, for, if the wire were pulled out immediately, the pile ends would fall away from the cloth.

FIG. 155.

FIG. 156.

Looms are made to weave two pieces of plush (which is a long cut pile, rather longer than velvet pile) in one loom simultaneously, one piece above the other, after the manner shown at [Fig. 156]. The principle is not used in cotton manufactures, although it has been tried. It is chiefly used for silk plush.