JACQUARD STOP MOTION
When working with two cylinders, one may happen to be turned at a time when it should not, and thus put the cards out of rotation. Many attempts have been made to overcome this difficulty by stopping the loom when the cards get out of the proper order, but none of the methods adopted have ever gained much favour. Recently a new motion has been patented, and is being applied to machines by Messrs. Devoge & Co., of Manchester. It is called the ‘Devoge jacquard stop motion.’
Fig. 44
[Fig. 44] shows how it may be applied to a machine. The hooks A and B and the needles E and F are those here used to work the motion. They may be at either side of the machine, but should be at the side of the belt handle. One hook must belong to the front cylinder needles, and the other to the back ones. The hook A requires a lingo attached to it to draw it down after being lifted. The hook B is attached to a lever connected to the side of the loom, so that when one end is raised a hammer on the other end pushes off the belt handle (a lever and bracket are supplied for the purpose). C C1 is a wire bell-crank lever with a turn or loop on it at D to act as a spring. The fulcrum is at L, on a piece of iron bolted to the edge of the machine; the lower end of this lever passes through an eye in the hook A at C1, and the upper end passes through an eye in the needle E. There is a spring on the point of the needle E, between the face-plate and the eye, which the lever goes through, and which holds the needle back as shown.
Each time the hook A is raised the lever presses forward the needle E, and with it the hook B, which would then be raised by the lower griffe, unless the card pressed the needle back again and pushed it off. Thus, by having a hole cut in the cards for the needle F, and none for the needle E, the hook B would never be raised; but if a hole is cut for E in a card following one in which a hole was cut for F, the hook B would be raised and the loom stopped. It is, therefore, only necessary to arrange the cutting of the cards to allow the loom to work when they are following each other in rotation; but as soon as one card gets out of order the loom should be stopped, though, perhaps, not till it has run for a few shots. Thus—
Number of cards—
Cut the large dots for the needle E.
Cut the large dots for the needle F.
This gives a repeat of twelve cards; but any number to suit may be used. Thus—
Number of cards—
Cut the large dots for the needle E.
Number of cards—
Cut the large dots for the needle F.
This gives a repeat of sixteen cards. The even numbers of cards go to the front or top cylinder, and the odd numbers to the low cylinder, and it may be seen that a hole in an even-numbered card following one in an odd-numbered card will not stop the loom; but a hole in an odd number following one in an even number will stop the loom, as it is the hook B rising after A that stops it; therefore any suitable rotation of cutting may be adopted, and the stoppage can take place either at short or long intervals, as desired, the principle being to raise the hook A two or three times, and push the hook B back again by having no hole cut for the needle E. Then leave A down for three or four shots, and cut holes for E, which have no effect unless the cards get out of rotation, and one of those with a hole cut to raise the hook A comes before one with a hole cut for the needle E, when B will be raised and the loom stopped. This is a good arrangement, and works very well.
Another motion for a similar purpose, invented by the writer, is shown in [Fig. 45]. It is based on the following principle: Suppose a cord is taken from any two hooks of the jacquard, and passed round a pulley on the ‘hound tail’ or long lever of the weft fork motion; if the cord is left slack, so that raising one of the hooks will just tighten it, then raising both hooks together will lift the lever, and can be made to stop the loom. The difficulty to be got over is that one of the hooks must belong to one griffe, and the other to the other one, in order to make the motion act with the two sets of cards. As the two griffes pass each other at the centre, or at the half-lift, this must be taken as the full lift, the cord must be stopped here, and not drawn any farther; for the remaining portion of the lift the hooks must draw a spring. This can be easily arranged by having loops on the cord passing round wires in the cumber board, or by having the two ends of the cord passing through a small hole board, and having knots or beads on them, beneath it. Other methods may also be adopted.
One of the most desirable arrangements is shown in the figure: A, A are the two hooks; B, B are two small springs by which the two levers, C, C are attached to the hooks with cords; D is the frame for holding the levers, and is fastened to the top rail of the loom, under the jacquard, or in any convenient place. It will be observed that the front bar of the frame passes above the levers, so that it will prevent them rising above the half-draw of the hooks, in which position they are shown. E, E are two cords connected with a jack or tumbler, F, on the end of a bell-crank lever, G H L, having its fulcrum at H, which may be on the same stud as the weft fork lever, or in any convenient place.
Fig. 45
The weight of F and G keeps the cords in tension, and the point L of the lever is set behind the lever on the loom which carries the weft fork, at such a distance from it that when one of the cords E is drawn it does not act on it; but when both hooks are raised, drawing up the two cords, the point L of the lever presses against the weft fork lever, pushing off the belt handle and stopping the loom.
The lever G H L may act directly on the belt handle, if desired; in this case it would be fixed outside the loom framing. The cards are cut on the same principle as for the last motion, but the same holes will do in both sets of cards, as the two needles are acted upon by the same number of holes in both back and front sets; that is, for two hooks coming beside each other.
The following order of cutting will answer:—
Number of cards—
Cut the large dots on the number of cards given, and of course they must be cut to suit the needles connected with the hooks used.
The above gives a continuous working of the motion, but it would be sufficient for it to work at intervals having 8 or 10 shots between them, as—
Number of cards—
This will not allow the loom to run for more than 20 shots after the cards get out of order.
Some other motions are in use, but these are simpler.
Before describing twilling machines or any special make of jacquards, it may perhaps be better to explain the mounting of ordinary machines, according to the usual methods adopted in some of the leading districts.
CHAPTER III
FULL-HARNESS MOUNTINGS
The mountings that will be alluded to in this section are all intended for ‘full harness’; that is, the ordinary method of jacquard weaving when applied to such fabrics as damask, dress goods, and, in many cases, to double cloths, handkerchiefs, &c.
Full harness, or, as it is termed in some hand-loom districts, shot and draft, to distinguish it from the ‘pressure harness’ system, holds the first place amongst mountings, as by it can be done what cannot be done by any other method, and everything can be done by it that can be done by any harness, or combination of harness or heddles; though it does not follow that it would be desirable to adopt it in every case. In a full harness each thread in any part of the tie can be lifted independently of the others; in wide fabrics, or in order to reduce expense in narrow ones, recourse is had to gathering or repeating the tie, and like threads in each repeat must be lifted together; but in a single tie any one thread can be lifted independently of any other. In full harness there is one thread of warp drawn into each mail or eye of the harness, and one shot is given to each change of card. Other descriptions of harnesses are known as ‘half harness,’ ‘split harness,’ ‘pressure harness,’ ‘gauze harness,’ double-cloth and quilt harnesses, &c.
Half harness is the term applied to that description of harness in which the half of the warp (every alternate thread) is drawn into the harness, and the other half passes through it loosely. This is mostly to be found in the manufacture of gauze or leno curtains, and is wrought with a shaft mounting in front of the harness.
Split harness is applied when two threads are governed by each hook of the jacquard, and the ground of the cloth is wrought by some other means, as shafts through the harness. This is to be found in the silk trade.
Pressure harness is when several threads of warp are drawn into each mail, and when the harness is drawn it remains stationary for several shots of ground texture, for which the sheds are sprung or pressed open by heddles.
Gauze harness is a harness fitted up with doups for weaving leno and gauze, and is mostly full harness.
Double-cloth and quilt harnesses are for weaving these fabrics.
Mounting, or gaiting, is a term that may be taken to apply to the building of the harness and the preparing of everything in connection with it. The form of ‘tie’ to be adopted will depend to a great extent on the nature of the fabric to be made, and to the style of pattern which is to be applied to it. For instance, dress goods may be required, and the pattern may consist of small sprigs or objects repeated over the surface of the cloth, forming a simple repeating pattern. Again, handkerchiefs, napkins, or table-covers may be wanted, which will require a bordered ‘tie,’ and may have both single and double mounting in them. Sometimes the manufacturer mounts his looms to what he considers a desirable ‘tie’ (or arrangement of cords) to admit of having a good variety of patterns wrought on it for whatever class of goods he is likely to make, and then he has the patterns made to suit the tie or mounting. Sometimes patterns are procured which will give the best possible effect on the least possible machinery, or the least number of hooks of the jacquard, and the mounting is then arranged to suit the pattern. On this method often a very considerable saving of machinery can be effected by turning over or gathering the harness; or, by arranging a variety of turns over, or gathers, and repeats, a very diversified effect can be obtained with a small number of hooks, as those accustomed to the larger forms of shaft mountings will readily understand. Thus, if we take 100 hooks of the jacquard as equal to 100 shafts, it will easily be understood that a large variety of beautiful patterns can be produced with either a straight or zigzag draft, though they will be mostly of a set or conventional type. The objection to mounting a loom in this way is, that if a change of pattern to a free or running style is required, it is necessary to cut down the harness and remount it, probably requiring new machinery as well. It may, however, suit to adopt both methods; that is, to have a few looms for working conventional patterns on small jacquards, say 200 hooks, and others mounted for free patterns requiring, say, 400 or 600 hooks in the machine. Of course this entirely depends on the nature of the orders likely to be received, and manufacturers must use their own judgment, in which, however, they are more likely to err on the narrow than on the liberal side of the question, the result being cramped and stiff patterns, with a probable loss instead of gain. Two styles of mounting harness are in general use—one, known as the ‘London tie,’ being used in Spitalfields by the silk weavers; the other is called the ‘Norwich tie,’ as it was there adopted in the early days of weaving. About 1830 the Norwich style was adopted in London, as the weavers’ houses were too low to admit of the jacquards being set high enough to suit the London method, which, having a quarter-twist in the harness, requires more height than is necessary for the Norwich system, in which the harness passes direct from the jacquard to the cumber board in flat rows without any twist.
The Harness.—When about to mount a loom the first process is to prepare the harness. A harness is built up of several parts, the methods of preparing and building varying in different districts. A few of the best methods will be given. [Fig. 46], Nos. 1, 2, and 3, show a complete cord of the harness in three methods of preparing it—A (Nos. 1 and 2) are the tail or tug cords looped to the hooks of the jacquard; these cords are only necessary on double-lift machines, and are usually put on by the machine-makers. They are made of twisted cotton, and are soft and pliable. L shows the knot, known as the ‘tug knot,’ by which the tail cords are looped on the hooks. B, B are two methods of knotting the neck or body of the harness to the tail cords; that in No. 1 is the usual method. C, C are the hecks, or guide reeds, through which the harness passes. G, G are the lingoes, or leads, formerly made of strips of lead, but now of wire. From the lingo to the mail or eye, F, through which the warp passes, is a double cord called the bottom piece, or hanger. From the mail, passing through the cumber board or harness reed E, is another piece of double cord, called the top or mid-piece, or the ‘sleeper’; to this is looped or tied the neck twine in various ways, two methods of which are shown at D d d1 (No. 1) and at D (No. 2); No. 3 shows levelling below the cumber board, with two methods for tying H and H1. M is the snitch knot, which is much used for fastening cords that require careful adjusting. Sometimes it is a matter of choice to adopt any method of mounting, and sometimes one plan may suit circumstances better than another.
Fig. 46
Preparing Lingoes.—A prepared lingo is shown at No. 4, [Fig. 46], this work being generally done by little boys or girls, or by old women. One of the commonest methods of preparing them is as follows:—Having prepared the mails, which are small eyelets of brass, copper, or steel of the shape shown at F, sometimes with round holes in the centre and sometimes with elliptical or long shaped ones, they are put into a dish or pan; a boy takes a piece of wire and strings a number of them on it. The wire is then fastened on a rack, or in any convenient place, by both ends, in a horizontal position. A bunch of small pieces of twine is tied up in a convenient place; these are to form the hangers, or to connect the lingoes with the mails. Having the lingoes conveniently placed, and being provided with a pair of shears, the boy sets to work. Taking a piece of twine, and pulling it through an end hole of a mail, he doubles it evenly, and, lifting a lingo, puts both ends through the eye in it, and casts on a knot, as shown at N (No. 4). The loop on the twine there shown requires to be pushed up over the top of the lingo, then drawn tight, and the ends clipped off. This mail is then pushed along the wire, and the others proceeded with. The pieces of twine for forming the hangers, as well as the sleepers, are prepared by warping them off spools round two pins, and then cutting them across. Of course the pins must be set apart at such a distance as will suit the length of the sleepers and hangers required. The usual length of the hanger (when doubled) is 7 or 8 in., and that of the sleeper or mid-piece when it passes through the cumber board, as in Nos. 1 and 2, [Fig. 46], and as shown at No. 4, is 15 or 16 in. When a quantity of lingoes are hung on the mails, the top cords or sleepers may be put through the top holes in the mails, and tied with a weaver’s knot, the ends being neatly clipped off.
Fig. 47
A quicker method of preparing lingoes is as follows:—Two upright pieces of iron, as A, A, [Fig. 47], are fastened on a board, or on a bench or table. A cut is made in each of these, so as to hold a piece of flat wire such as is used for coarse reeds. This wire is pointed at one end, so that by taking a handful of mails they can easily be gathered up on it. It is then placed in position, as shown at B; the mails, D, are shown on it, and C is a spool containing twine for the hangers. By rubbing the end of this twine with wax, so as to stiffen it, and gathering all the mails on the wire evenly together, the end of the twine may be run through the holes in all of them at once. This end is fastened, and with a hook, as shown at F, the twine can be drawn through the mails, beginning at the one farthest away from the spool, and passing from one to the other in succession, looping the twine round the pin E, which should be at such a distance from the mails as is required to make the hangers the proper length. If many mails are to be threaded at once there should be two or three pins as E, so as to avoid too much slope from them to the mails, which would increase the length of the hangers. The twine can be cut when the mails on the wire are completed, and the other ends of the mails turned round and treated similarly for the sleepers; but the pegs will require to be shifted, so as to get the required length of twine. When finished, these can be cut also, and the wire tied up in a convenient place, so that the lingoes may be hung on, as before described. The sleepers can then be knotted, if required to be.
After the lingoes are thus prepared the twine is frequently varnished, and sometimes twisted so as to prevent that of the hangers from rising up through the hole of the mail and getting in between the two halves of the yarn when the shed is crossing. This frequently happens if anything prevents the lingo from dropping. A common method of twisting them is for a boy to give them a coat of flour-paste or a light coat of varnish, then, having them hung on a rod which passes through the loops of the sleepers, he takes a handful of the lingoes, and, placing them on his knee, rolls them round with his hand till they are sufficiently twisted, then lets them hang down, and proceeds with another handful.
When the paste or varnish on these is set they can be well varnished. About two inches at the top of the sleepers must be left without varnish, to leave it soft and pliable for tying the neck to; the knots on all the sleepers must be brought up to about the point before they are twisted or varnished. When the lingoes are thus prepared and dry they can be tied in bunches, to be used as required.
Some do not varnish the twines till the harness is all mounted, and then varnish it all over. Others do not varnish at all. In this case the hangers are not twisted, and for light open sets of harness they need not be twisted at any time.