The Fabric of Civilization Part 7

The conveying of the sliver (p.r.o.nounced with a long or short i) into the can is in itself an exceedingly ingenious operation, although a very simple one. The device is attached directly to the card, and is called a coiler. The sliver pa.s.ses into it from the funnel. The hole from which the sliver emerges is off the center of a steel plate which revolves slowly, so that the sliver, as it comes out, has an eccentric motion which causes it to fall into the can in regular coils. Tangling is thus prevented, and ease of handling secured.

Combing Necessary in Spinning Fine "Counts"

Combing is necessary in the preparation of cotton for the spinning of fine "counts" or coa.r.s.er yarns where great smoothness and regularity are desired. They are now quite extensively used in the United States, and it is significant of the trend of the industry here that the number is rapidly growing. The first cotton comber was invented by a Frenchman of Alsace named Heilmann. The patent was issued in 1845. Now there are on the market other machines, both English and American, similar in principle but improved in many ways.

[Ill.u.s.tration: _Revolving flat cards_]

The first of these preliminary processes is that which is done by the sliver-lapper. The slivers from 14 to 20 cans are drawn along side-by-side, pa.s.sing between three pairs of drawing rollers which will be described later. From the drawing rollers the slivers now reduced in size, pa.s.s between two pairs of calendar rollers from which they emerge, not as a sliver, of course, but once more as a lap about a foot wide.

These laps are usually pa.s.sed to a ribbon lapper, where six of them are placed end-to-end, and unrolled simultaneously, pa.s.sed between four pairs of drawing rollers, and then superimposed, one upon the other, and, calendered once more, issued as a lap a little less than a foot wide.

This process may be repeated as many times as the quality of the yarn desired may require, for each drawing process served to straighten the fibers and so to render the thread more even and capable of finer spinning.

Combing is exactly what its name implies. The lap is actually raked by a fine-tooth comb with needle-like teeth of steel ranging from 16 to 90 per inch. This involves breaking the lap again and the intricacy of the comber rests in the mechanism which it employs for joining the separated ends.

[Ill.u.s.tration: _Cross-section diagram of revolving flat card_]

Six or eight laps go through the machine at once, and the product is combined, condensed, formed into a continuous sliver, and deposited once more into cans. The process is not a fast one at best, and the chief contribution of American inventors is in the direction of speed. Each nip combs only 4/16 to 4/10 of an inch of fiber. The Heilman machine made about 85 or 90 nips per minute. The American improvement makes 130 to 135. The width of the lap in the American machine is likewise increased, and the saving in labor, therefore, is considerable. English improvements have been in the same direction, the resultant saving being almost as great.

[Ill.u.s.tration: _Ribbon lappers_]

Though many of the processes already described might be called drawing, in a sense, insomuch as they involve a continual lengthening and straightening of the lap or sliver, yet drawing in the strictest sense has not yet begun. It may be done only once, for coa.r.s.e and cheap yarn, or it may be repeated a half dozen or more times to produce the finer and more expensive products. The frame for each repet.i.tion is slightly different, but several types may be isolated. They are, in the order of their use, the drawing frame, the fly frame, or slubber, the intermediate frame, and the roving and jack frames.

For fine counts the slivers from the comber, and for other grades that which comes directly from the card, are taken, then to the drawing frame.

The slivers from the cans, six or eight in number, are fed through one aperture, and pa.s.s, thus combined, between several (usually four) pairs of rollers, so arranged that each succeeding pair revolves at a more rapid rate than that which preceded it. The last pair in the series revolve probably six or eight times as fast as the first pair. This combination of rollers pulls constantly on the more or less irregular slivers, rendering them always more nearly uniform in diameter and density, the thickness of one of the entering slivers serving to counterbalance the thinness of the other. The drawing frame consists usually of four or five "heads," and the sliver, after it pa.s.ses through one of these "heads," is put through a second one, along with other slivers, so that the doubling and redoubling goes on constantly. There is an electric device to stop the machine when a sliver breaks, either at the back or the front of the frame.

[Ill.u.s.tration: _Combers at work in a mill spinning fine counts_]

From the last head of the drawing frame, the sliver pa.s.ses to the fly frame or slubber, which not only continues the drawing and doubling, usually between three pairs of rollers, but through the aid of a device which gives the sliver a slight twist and winds it, for the first time, upon a spindle. This device is known as the flyer, and is, roughly, a U-shaped piece of metal, which, revolving, inverted, over the spindle, gives the thread a slight lateral twist as it coils upon the spindle. The latter also revolves, but with a diminis.h.i.+ng motion so that the amount of twist may be kept uniform as the diameter of the coil upon the spindle increases. The sliver, now being twisted, is called a sliver no longer, but the slubbing.

The slubbing is pa.s.sed between the rollers in pairs, the emerging product being less in diameter than the diameter of a single slubbing. The machine combines the fourfold process of combination, attenuation, twisting and winding. There are more spindles upon this frame than upon the slubber.

The last drawing frame, except for very fine yarns spun from Egyptian or Sea Island staples, is the roving frame, similar in principle to the last two but containing still more spindles. It receives the rovings from the intermediate frame, combines two of them into one, twists them a little more, and winds them upon the spindle tubes. The Jack frame is similar except that its product is finer and smoother.

[Ill.u.s.tration: _Sliver lappers in a Northern mill_]

It is interesting to note, however, that the majority of improvements have been the fruit of the brains, not of Americans, but of Englishmen.

Copeland points out that this may be due to the English desire to save in the consumption of cotton, but that more probably it is due to the development of fine spinning in England, in which most of the machines here described are chiefly valuable; and he ventures the prediction that now that American mills have definitely gone in for the finer counts, it may be expected that engineers here will apply themselves to the improvement of this machinery.

[Ill.u.s.tration: _Drawing frames, turning slivers into roving_]

The "Mule" Versus the Ring Spindle

Spinning is the final process which turns the cotton into firm, coherent yarn, sufficiently twisted, and ready for the loom. The twist given to the thread by the previous machines has been only enough to make the fibers hold together. They are still comparatively loose and fluffy, and their tensile strength is slight.

There are, in general, two types of spinning machines. The first, the mule, an English product. The second, radically different, is entirely American. It was invented in 1828 by James Thorpe, and immediately found some favor, but it was not until the Civil War that it was received on equal terms with the mule. Today, however, it dominates in the United States, the comparative figures in 1917 being: ring spindles 30,264,074; mule spindles 3,634,761. The disparity is growing greater every year, and the use of the ring is firmly established in other countries as well. The figures for 1907 were:

_Mule_ _Ring_ England (1909) 39,800,000 7,900,000 Germany 5,740,000 3,722,000 France 4,122,000 2,481,000 Austria 2,307,000 1,277,000 Italy 1,015,000 1,852,000 Russia 1,031,000 1,320,000

The mule, by reason of the great size to which it has been developed, and the impressiveness of its large, rhythmic motion, is one of the most formidable of all cotton machines, as indeed it is one of the most complex. It received its name from the fact that, performing two princ.i.p.al functions--drawing and spinning--it was regarded as a hybrid, just as the mule is a hybrid cross between the horse and the donkey.

In the mule (see diagram on page 53), which is a long and wide machine, carrying sometimes, in new models, as many as 1,300 spindles, the drawing and twisting are not continuous but consecutive. The rovings (B) are held on a creel (A) at the back of the machine, usually in three or four tiers, or on long beams or spools. They pa.s.s from the creel, or spools, between three pairs of drawing rollers (C.) Coming out of the rollers, they are fed to the spindles on the carriage which backs away from the creel and recedes somewhat faster than the rovings are unwound. This receding is the essential motion of the mule, for thus the cotton receives its final drawing. The spindles, meanwhile, are revolving rapidly, spinning the yarn. The twist goes first to the thin places where the least resistance is offered. Then, as the carriage carrying the whirling spindles continues to back away, the thicker parts of the thread, being comparatively untwisted are pulled down to the average diameter and are twisted in turn. The carriage usually runs back about sixty-three inches. At the termination of its run, or stretch, the spindles increase their speed until the twisting is completed and the carriage starts on its return trip. This reverses the spindles, and the thread which has been wound upon them is unwound, the slack being taken up by one guide wire (D) while the other guides the thread to the winding point, and winds it up in the opposite direction on the cone-shaped cops on the spindles. The rollers do not feed out more roving as the carriage returns. Hence, there is no slack when the round trip is completed.

[Ill.u.s.tration: _Slubbers, showing the U-shaped flyers_]

Except for the use of drawing rollers, there is little similarity between the mule and the ring frame. The latter has no movable carriage, none of the splendid sweep of motion that makes the mule so fascinating to watch. The ring-frame is simple and business-like, and its speed is amazing. The bobbins holding the roving are placed directly over the spindles. Around each of the latter is a steel ring. There are at least 112 spindles on each machine, and all the machine rings for the spindles are fixed in a single frame. The upper edge of the ring is f.l.a.n.g.ed, like a miniature railroad track, and snapped over the f.l.a.n.g.e is a small but important C-shaped steel ring, called the traveler.

How Thread is Spun on the Ring Spindle

When the machine is in operation (See diagram on page 56) each roving (H) leaving its bobbin, runs through the usual drawing rollers (G) then through a guiding wire to the ring, where it is pa.s.sed through its traveler (B) which is always at the winding point on the spindle. As the spindle and the rollers revolve, the roving is fed out at a considerably slower rate than the spindle takes it up, so that there is always a tension on the thread. The whirling spindle thus pulls on the traveler, drawing it round and round on its f.l.a.n.g.ed track (A). It revolves just a little more slowly than the spindle and thus the yarn receives its twist.

Meanwhile, the frame (C) on which the rings are fixed moves slowly up and down, so that the winding is properly regulated.

It is possible to operate the spindles at a remarkable speed. So perfect are the bearings which have been evolved that the average speed is ten thousand revolutions a minute, and on fine yarns it is sometimes 12,000 to 13,000 revolutions. The speed is limited by only two factors: the first is the ability of the operator to make splicings when threads break, and the second is the tendency of the traveler to fly off when the speed is too high. The number of travelers consumed is high at best, and in a mill which has long been in operation the floor in the front of the frame is likely to be paved with the little steel rings which have fallen and been ground into the planks by the heels of the worker.

[Ill.u.s.tration: _Diagram of mule_]

The battle between the advocates of the ring frame and those who favor the mule is still on. For the American spinner the ring has undoubtedly many advantages. Because it spins continuously, and not intermittently, it turns out about a third more yarn per operator. It is usually admitted, however, that the thread from the mule is more even in diameter. Advocates of the mule say, moreover, that the thread from the mule is softer and "loftier", and that cloth woven from it has a more "clothy" feel. But others say they can produce soft yarn with the ring.

In the United States, where the labor cost is a vital item, the ring-spindle has an a.s.sured place.

[Ill.u.s.tration: _Mules at work_]

The yarn is now a finished product. It may be sold by the spinner to the weaver or it may be woven in the mill in which it is spun. Before it is ready for the loom, however, there are a number of operations which must be completed.

The yarn from the ring frame, or mule, is wound in a large cop, or on a bobbin. It must be put upon spools before it can be warped. The spooler is a simple machine, but one that requires constant attendance. In the spooler, bobbins are placed upon holders or spindles, and the thread is pa.s.sed over a series of guides to the spool, up above. The spool revolves at a high rate of speed, and the thread is wound evenly upon it. The operator must watch for broken threads, retie them, replace the empty bobbins by full ones and see that the empty ones are gathered up uninjured. She--the operator is usually a girl or woman--must be alert and active, and especially nimble fingered.

[Ill.u.s.tration: _"Close-up" of Ring Spindle in American mill_]

One of the most important inventions, one that was received with acclaim by the American manufacturer, and one which actually reduced his labor cost on spooling no less than ten per cent. at one clip, is a tiny little thing that is held in the palm of the hand. This is the Barber knotter.

When a thread breaks, the attendant places the two ends together in the machine and by the mere pressure of her thumb ties the knot much better than she could do it without the knotter. The economies which it effects extend beyond the mere spooling, for better knots mean fewer breaks in the warping process, and a better cloth at the end of weaving.

The spools from the spooler are placed on a large frame, called a creel.

The creels have an average capacity of about 600 spools, and there are usually 16 to 20 in one tier. The threads from the spools are drawn between the dents of an adjustable reed, then under and over a series of rollers. From here they are led down to the beam, upon which they are wound. The revolving of the beam unwinds the yarn from the spools and winds it regularly and evenly upon the beam itself. There is a device for measuring the length of the warp wound, and stop motions for arresting the operation should a thread break or other accident occur.

[Ill.u.s.tration: _Each operator at these spoolers has a Barber knotter on her hand_]

The yarn of the warp must usually be impregnated with a sizing which will smooth out and stick down its furry surface and add as well to the tensile strength so that the strain of weaving may be withstood. For this the most effective and most generally used machine is the slasher, the chief feature of which is a roller, whose lower side is immersed in the sizing solution. Threads from the warp beam are run around this roller through the solution and then dried, after which it is finally wound on another beam for the loom. A considerable number of loom beams can be filled from one set of the warper beams mounted in the slasher.

The lengthwise threads of a fabric are called the warp. The crosswise threads are called the weft or filling. To make cloth, the warp and weft must be interlaced with each other in a suitable manner. The operation is called weaving, the machine in which it is performed is, of course, the loom. The princ.i.p.al operations of weaving are as follows:

1. Shedding, or the raising and lowering of the alternate threads of the warp, so that the weft may pa.s.s under and over them.

This is done by means of the harnesses and their heddles.

2. Picking, or placing a thread of the weft between the warp threads so raised and lowered by means of the shuttle.

3. Beating-up, or pus.h.i.+ng, each thread of the weft into its position close against the thread which has preceded it by means of the reed.

4. Letting-off, or permitting the warp to unwind from the beam only just as fast as is needed by the speed of the weaving. This is accomplished by friction bands and weights on the warp beam.