Cotton Weaving and Designing / 6th Edition :: CHAPTER I PREPARATORY PROCESSES

CHAPTER I PREPARATORY PROCESSES

YARN intended for manufacture into cloth requires to pass through various stages of preparation, the character of which depends upon the class of fabrics to be produced. Thus, some systems of treatment are better adapted for the preparation of yarn for grey cloths (i.e. of the native colour of cotton), some for mono-coloured, and others for multi-coloured, fabrics. The choice of a system is often arbitrary, and can only be made from a knowledge of local or special requirements.

The operations involved in the preparation of warps for most fabrics are comprised under not less than five chief divisions, namely—

1. Winding yarn from any of its earlier stages on to warpers’ bobbins.

2. Warping.

3. Sizing.

4. Beaming, or winding yarn on to a weaver’s beam.

5. Looming, i.e. either drawing-in or twisting-in.

Each of these operations may be performed by a variety of machines of distinctly different types that have been specially devised to meet specific requirements, and which are, therefore, better adapted than others for their special purpose. Before introducing the reader to the details of the various types of machines in each division, it will be better to briefly enumerate the different systems of preparation usually adopted in the manufacture of the three classes of goods named above.

Grey warps are prepared by one or other of two systems, namely, (1) Beam warping, for slasher or tape sizing; and, (2) ball or mill warping, for ball or warp sizing; but by far the greater number are prepared by the first-named system.

1. Beam Warping and Slasher Sizing.

This system comprises the following operations, namely—

1. Winding yarn from cops, ring, or throstle bobbins on to warpers’ bobbins, by means of a “spindle” or “cop” winding machine.

2. Beam warping, whereby yarn is transferred, in the form of a wide sheet, from warpers’ bobbins on to a large flanged beam.

3. Slasher or tape sizing, whereby yarn is withdrawn from several beams, termed “back” or “slashers’” beams, to be sized, and subsequently re-wound by the same machine on to a weaver’s beam by simultaneous operations.

4. Looming, by which the threads of a new warp are placed in a loom ready for weaving.

2. Ball Warping and Sizing.

This system comprises the following operations, namely—

1. Winding yarn from cops or ring bobbins on to warpers’ bobbins.

2. Ball warping, in which a number of threads are withdrawn from warpers’ bobbins and condensed into the form of a rope of untwisted strands. This operation may be accomplished by several types of machines. The one usually employed is the old-fashioned warping mill, which coils warp-ends on to a large revolving reel or swift, from which they are subsequently withdrawn and formed into a large ball. Ball warps are also sometimes formed direct from warpers’ bobbins; also sometimes from sections formed by a sectional warper; and sometimes by means of a linking or chaining machine.

3. Ball-warp sizing.

4. Beaming, or winding a warp in an even sheet of threads on to a weaver’s beam for the loom.

5. Twisting-in or else drawing-in warp-ends in the loom.

If the threads of a new warp are similar in number and counts to those of the finished warp, and are to pass through the shedding harness and reed also in a similar manner, it is more economical to twist the threads of a new warp separately to the corresponding threads of the old warp, and then draw the twisted portion of the warp bodily forward through the healds and reed. If, however, the number of threads and counts are greatly dissimilar, or if a different drafting is required, then recourse must be had to drawing new warp-ends through the harness and reed.

Preparation of Mono-coloured Warps.

Warps of one colour may be prepared from either (1) warp-dyed and sized yarn, or (2) from hank-dyed and sized yarn.

1. (a) Warp-dyeing and Sizing.

The series of operations in this system are identical with those involved in the preparation of grey warps by means of ball warping, but with the additional process of dyeing immediately following the operation of warping, and are as follows:—

1. Winding yarn on to warpers’ bobbins.

2. Mill or other system of ball warping.

3. Warp-dyeing and sizing.

4. Winding yarn on to a weaver’s beam.

5. Twisting-in or drawing-in.

1. (b) Warp-dyeing and Sizing.

A system by which warps of one colour may be prepared by means of sectional warping, from ball-dyed and sized yarn, has been recently introduced. It comprises the following operations, namely—

1. Winding yarn from cops or ring bobbins on to warpers’ bobbins.

2. Mill or other system of ball warping.

3. Warp-dyeing and sizing.

4. Winding yarn from ball warps on to warpers’ bobbins by means of a warp-winding machine.

5. Sectional warping and beaming.

6. Drawing-in or twisting-in.

2. Hank-dyeing and Sizing.

This system involves the following operations, namely—

1. Reeling yarn from cops or ring bobbins into single or multiple hanks. (A standard hank contains 840 yards.)

2. Hank-dyeing and sizing.

3. Winding yarn from hanks on to warpers’ bobbins by means of a drum-winding machine.

4. Beam warping.

5. Beaming, or winding yarn from back beams on to a weaver’s beam.

6. Drawing-in or twisting-in.

Sectional warping may be substituted in lieu of beam warping.

Preparation of Multi-coloured Warps.

Striped warps are usually prepared by one or other of two systems, namely, (1) Yorkshire dressing, from warp-dyed and sized yarn; and (2) sectional warping, from hank-dyed and sized yarn. Warp-dyeing yields a more uniform tone of colour than hank-dyeing, for which reason some manufacturers prefer to adopt the former system, although the latter system is less costly.

1. Yorkshire Dressing.

This system comprises the following operations, namely—

1. Winding yarn on to warpers’ bobbins.

2. Mill or other system of ball warping.

3. Warp-dyeing and sizing.

4. Yorkshire dressing, by which the required number of threads of each colour are split off reserve ball warps. The warp-ends thus split off are subsequently passed, in groups of two to four, through the dents of a reed in proper order, according to the required warp pattern, and wound on to a weaver’s beam.

5. Drawing-in or twisting-in.

2. Sectional Warping.

This system comprises the following operations, namely—

1. Reeling yarn into hanks.

2. Hank-dyeing and sizing.

3. Winding on to warpers’ bobbins by a drum-winding machine.

4. Sectional warping, by which a warp is wound in sections upon wooden or compressed paper blocks, with warp-ends in the same relative position that they are required to occupy in cloth. Each section forms a complete unit of the full warp, and when the required number of units are prepared, they are placed together side by side, and compressed upon a mandril; then the yarn is unwound from all sections simultaneously, and wound on to a weaver’s beam.

5. Twisting-in or drawing-in.

Preparation of Weft Yarn.

If weft yarn is to be woven in a grey state, it is rarely that it requires to undergo any operation after it leaves the spinner. Grey cops and ring bobbins of weft are usually placed in a shuttle and woven direct; but if they are too large for a shuttle, their yarn is transferred on to wooden or paper bobbins by means of pirn winding.

Cops intended for use as weft are frequently dyed and bleached in that form, and woven without any operation of winding. If, however, weft yarn is dyed or bleached in hanks, it requires to be subsequently wound on to pirn bobbins or paper tubes to fit on a shuttle tongue. Weft is also sometimes woven in a damp condition, with a view to inserting a greater number of picks per inch in cloth than is possible with dry weft.

Winding Machines for Warp Yarn.

Fig. 1 is a diagram showing parts of a “spindle” or “cop” winding machine, which is chiefly employed to wind grey yarn from cops, G, or ring bobbins on to warpers’ bobbins, E. It is also sometimes incidentally employed to wind coloured yarn from hanks, O (as represented on the left-hand side of the diagram), when the amount of work required of that kind would not justify the purchase of a “drum” winding machine, which latter is better adapted for that purpose, for reasons that will be explained later.

FIG. 1.

As usually made, a “cop” winding machine contains a tin driving drum, B, passing centrally down the machine, and carrying the driving pulleys at one end of the tin drum shaft A. By means of cotton bands, C, the tin drum drives four rows of spindles, D, arranged in two zigzag rows, one on each side of the machine, as shown in part plan (detached). Warpers’ bobbins, E, fit loosely upon the spindles, and rest upon metal discs, F, secured to the spindle-shanks, by which bobbins are frictionally rotated. During winding, yarn passes from cops, G, or other source, over a drag-board, H, through a brush, I, and clearer guide, J, thence over a glass rod, K, surmounted on guide-rails, and on to warpers’ bobbins, E. The drag-board H is covered with flannel to impart frictional resistance to yarn, and thereby prevent its passing too freely and making soft bobbins. The clearer guide (of which a front view is shown, detached) is a thin metal plate containing a number of vertical slits, L, from near the top of which are two short slits, M, branching upwards at an angle of about 45°. The vertical slits serve to guide threads to their respective bobbins, and also to remove any irregularities, as “slubbings” (i.e. thick, soft places consisting of a mass of untwisted fibres). The short slits are intended to prevent operatives from raising threads out of the guides, and so save themselves the trouble and loss of time involved in piecing up broken threads.

Spindle-shanks, D, are furnished with tightly-fitting grooved pulleys, N, termed “wharves,” around which driving bands pass. Wharves on each back row of spindles are usually made one-quarter of an inch larger in diameter than those of front spindles, to cause them to revolve at a slower velocity. The object of this is to enable some compensation to be made for the constantly accelerating pace at which yarn is wound, in consequence of the gradually increasing girth of bobbins by additional layers of yarn. When bobbins become about half full on front spindles, a winder removes them to back spindles to be filled.

If bobbins were allowed to fill on front spindles, the velocity at which yarn would travel towards the completion of winding would impart an abnormal degree of tension to it, and thereby make it more liable to break. It is in consequence of the excessive degree of friction to which yarn is subjected in a cop-winding machine that renders it unsuitable for winding yarn that has been previously dyed and sized.

FIG. 2.

One of the most important parts of a cop-winding machine is the traverse motion to guide yarn between the flanges of a bobbin during winding. These are constructed in great variety, but all belong to one of two distinct types, namely, those governed by cams, and those governed by what is termed a “mangle-wheel.” They are also constructed to guide yarn at either a uniform or variable pace between the bobbin flanges. If the traverse of yarn is uniform, bobbins will be wound with a uniform diameter; but if a barrel-shaped bobbin is required, the movement of guide-rails must be differential—quicker towards the extremities, and slower towards the centre of their traverse, with the object of placing a greater quantity of yarn upon them. Traverse motions are usually designed on the compensating principle, so that guide-rails on either side move in opposite directions at the same time, and a falling rail helps a rising one to ascend, thereby requiring less motive power to drive a machine.

FIG. 3.

One of several modifications of a heart-cam traverse motion is shown in Fig. 2. In this motion two heart-cams, Q, are set in opposite direction upon a shaft, P, which is driven by a pinion, R, on the tin drum shaft, A, and a train of wheels, S, T, U, V. The cams operate treadles, W, whereby they fall and rise alternately. The free end of each treadle farthest from its fulcrum is connected by means of straps or chains, X, to pulleys; Y, secured to shafts; Z, extending one on each side of the machine, and carrying several pinion wheels, 1, at intervals. The latter engage with teeth in vertical racks, 2, which serve as supports to guide-rails, 3. Thus, as treadles are depressed, guide-rails are raised in a positive manner; but their return is effected by gravitation. The character of movement imparted to guide-rails depends upon the conformation of the cams, which may be constructed to give either a uniform or differential traverse to guide-rails, as desired.

Another modification of a heart-cam motion is illustrated in Fig. 3. In this motion a single cam, H, serves to operate both guide-rails, B, by acting upon two treadle bowls, one of which, K, is placed above, and the other, L, below the cam. Treadle bowl K is carried at one end of a lever fulcrumed at O, whilst the other end, M, is connected to a lever, Q. Through the medium of chains and chain pulleys, lever Q operates the guide-rail on the left, whilst the lower treadle, T, operates that on the right.

FIG. 4.

A traverse motion constructed on the mangle-wheel principle, to wind barrel-shaped bobbins, is represented in Fig. 4, A pinion, B, on the tin drum shaft, A, drives wheel, C, which carries a small pinion, D. Wheel C and pinion D are carried by a bracket that permits of a slight concentric movement of those wheels to enable the pinion to engage alternately on the outside and then on the inside of the mangle-wheel E, with which it gears. On the same stud as the mangle-wheel is a pinion, F, which engages with the teeth of a horizontal rack, G, which is formed with a curved rack at each end. The curved racks gear with eccentric wheels, H, fastened to shafts, I, which carry chain pulleys, J, to wind up or let off the chains connected to the supports of guide-rails. When pinion D revolves on the outside of the mangle-wheel, the latter revolves until the gap K arrives at the pinion, which immediately runs inside the mangle-wheel and reverses its direction, until the gap L arrives at the pinion, which then runs on the outside and again reverses the direction of the mangle-wheel. Thus, rack G is slowly moved from one side to the other, and by acting upon the eccentric wheels H at different distances from their axes, their rotation is quicker or slower, according as the racks are in gear with them at a point nearer to, or farther from, the centre of their shafts respectively. On the same shafts as the eccentric wheels are a number of chain pulleys on which are fastened chains, M, connected to the supports, 2, of guide-rails, whereby the latter are raised and lowered in a manner determined by the eccentric wheels.

FIG. 5.

Another modification of a mangle-wheel motion is shown in Fig. 5. In this motion a wheel, E, on the drum shaft, drives the larger wheel F. The small pinion C turns the mangle-wheel H.

In order to obtain the unequal motion of the rack R, to give the barrel shape to the bobbin, a wheel, A, is fixed on the mangle-wheel shaft a short distance from the centre of the wheel. Another wheel, B, is fixed in a similar manner on another shaft, which also carries a wheel which gears into the under side of the rack. The smaller side of the wheel A gears into the larger side of the wheel B, as shown in the diagram, and as the mangle-wheel shaft revolves, the larger part of A will gradually come in contact with the smaller part of B, and this, of course, will cause the rack to move quicker. When the smaller side of A is in contact with the larger side of B, the guide-plate will be guiding the yarn on to the middle of the bobbin; and when the larger side of A is in contact with the smaller side of B, the guide-plate will be putting the yarn on to either the top or bottom of the bobbin.

FIG. 6.

The small side of the wheel A must be set in gear with the larger side of the wheel B, and the traverse halfway of the bobbin. The pinion C will at the same time be in contact with the middle pin in the mangle-wheel, and the middle of the rack R driving the wheel M.

Fig. 6 is a part elevation, and Fig. 7 a plan, showing the essential parts of a drum-winding machine to wind yarn from hanks, W, that have been previously dyed and sized, on to warpers’ bobbins, C. In this type of machine, warpers’ bobbins are held horizontally against the peripheries of a series of revolving drums, B, fixed at regular intervals upon a shaft, A, running centrally from end to end of the machine. Bobbins are held in position by spindles, D, contained in frames, E, which are fulcrumed at F to brackets, G, to permit of bobbins rising as they increase in size. Since bobbins are driven by surface contact with drums, the rate of winding is approximately uniform throughout. Projecting from each bobbin frame is a latch, H, to permit of a hook, I, holding a bobbin out of contact with its drum, whilst an operative replaces a full bobbin with an empty one, or pieces a broken thread.

FIG. 7.

FIG. 8.

FIG. 9.

Yarn is guided between the flanges of bobbins at a uniform pace by means of guides, J, carried upon guide-rails, K, supported in brackets, L, and operated by a heart-cam, M. On the end of the driving shaft, A, is a worm, N, which gears with a worm wheel, O, with which is compounded a pinion, P, to drive wheel, Q, to which the cam M is secured. As the cam revolves, it acts alternately upon two runners, R and S, carried upon studs secured to the sliding base, T, of brackets, L, whereby the latter receive a reciprocal motion, as indicated by arrows, U and V.

Winding Machines for Weft.

When weft yarn is in an unsuitable form to be placed within a shuttle it is usually wound upon paper tubes, or wooden bobbins, by means of one of the many systems of “pirn” winding. The chief parts of the prevailing type of machine used for that purpose are represented in Figs. 8, 9, and 10, which are end and front elevations and plan respectively. Passing centrally down the machine is a tin drum, B, on driving shaft, A, for the purpose of driving a number of wharves, C, arranged at regular intervals on each side of the machine. Fixed immediately above each wharve is a metal pirn cup, D, having a conical interior, for the reception of a pirn bobbin, E. When in position, a long spindle, F, having a heavy head-piece, G, passes through a bobbin tube and enters a rectangular hole in the wharve immediately below. The lower portion of a spindle which enters the wharve is also rectangular in cross-section, and therefore revolves with its wharve. At the same time, bobbins are driven by causing a projection, H, below spindle heads to enter a slot in each bobbin head.

FIG. 10.

Each thread passes from its source, over several stationary bars, to impart the required degree of tension to it, thence over guide-rail, I, by which it is guided up and down (as indicated by arrows, J) between the extremities of a pirn cup, as it passes through an opening, K, in the latter, and on to its bobbin. In consequence of yarn being built upon a bobbin within a conical chamber, a bobbin, with its spindle, rises automatically as it fills with yarn, and when filled it raises its spindle clear of its wharve, and thus stops automatically.

FIG. 11.

Guide-rails, I, are usually operated by means of a grooved cam, L, fixed on a side shaft, M, which carries a worm wheel, N, driven from a worm, O, on the end of a driving shaft, A. The cam acts upon a runner, P, fixed on a sliding rail, Q, in which are formed vertical slots, R, one on each side of the machine. Each vertical slot acts upon a runner, S, secured to lever T, having shaft U for a fulcrum. At regular intervals on shaft U brackets are fixed to support guide-rail I, which rises and falls at a uniform pace in both directions.

In consequence of yarn rubbing against the stationary surface of a pirn cup, it is liable to become burnished, and sometimes injured. Many attempts have been made to overcome that objection by driving bobbins by surface contact with revolving discs, and also by supporting them against conical rollers. Fig. 11 shows one of several methods of driving bobbins by means of bevelled discs, B, fixed at regular intervals upon driving shafts, A, placed one on each side of the machine. In this machine, as in an ordinary pirn cup machine, a bobbin, C, rises automatically until filled, when its spindle, D, withdraws from a hole in the bolster, E, and slides down a short incline, thereby stopping a bobbin by carrying it from the disc.

The three methods of warping in use are mill warping, beam warping, and sectional warping. The oldest form is mill warping, but this has been largely superseded in almost all cases, except for coloured goods, by the beam warping machine.

FIG. 12.

FIG. 13.

FIG. 14.

In beam warping bobbins are placed in a creel. This is a frame constructed to hold from 400 to 500 bobbins, and is the shape of the letter V, as this is the most convenient and easiest for unwinding. The 400 to 500 threads, A, are taken through an expanding reed, B (Figs. 12, 13, and 14). The ends are then passed over a tin measuring roller, D, and under tension-rollers, 15 and 18, which keep the yarn taut, and also pull it back when it is required to turn backward to find a broken thread, or otherwise. Each thread is then passed separately underneath a small bent wire drop-pin, 22. Each thread bears the weight of one of these wires, and should the thread break when the machine is in motion, the wire falls between two rollers, 3 and 4, which latter is mounted so that a wire causes it to move forward and, by releasing a “trigger” motion at Q, as it is called, the machine is automatically stopped. This is the principle of Singleton’s stop-motion, which is the one most commonly used. In front of the stop-motion wires the yarn is passed through an expanding comb, 23, which regulates the width of the slashers’ or “back” beam, 26. This beam is driven by friction; the beam rests on a drum, V, and as the drum revolves, the beam is driven in such a manner that yarn is wound at a uniform pace throughout, although the beam is gradually increasing in diameter. One of these machines will supply about 80 to 90 looms weaving medium counts of yarn. The creel is usually made to hold 504 bobbins, but any lesser number of ends may be put on a beam.

After leaving the warping machine the beams are taken to the slashing frame, where a sufficient number of beams are put together to form the warp for the loom.

Mill warping.—This system of warping is still in use for warps used in the Bradford mixed goods trade, and for many classes of coloured cotton goods in Lancashire, although slashed warps are fast superseding the system for the former trade, and sectional warping is replacing the system for the coloured trade. Mill warping is also in general use in silk manufacture. Those spinners who supply warps to Yorkshire worsted manufacturers have usually supplied them in the ball, unsized. The warps are “mill” warped, and the manufacturer has them sized to his own orders by cotton warp sizers, who usually combine this business with dyeing and finishing in the Bradford district. Slashed warps are now being used in the Bradford trade to a considerable extent, the warps being in most cases slashed in Lancashire and sent on beams.

FIG. 15.

A warping mill consists of a large reel, Z (Figs. 15 and 16), of from six to twenty yards circumference, which is made to revolve. This reel is fixed upright in suitable framework, and the warper’s bobbins, W, are placed in a creel, V, by the side of the reel. The ends are taken from the bobbins, and drawn separately through the eyes of a row of needles, T, which constitute what is termed a “heck.” This heck is so constructed that one-half of the eyes can be raised above the other half, to form a lease. The heck slides up and down the framework Y of the mill, and thus forms a traverse and distributes the warp as the reel revolves. At the commencement of a warp, the bunch of ends is taken from the “heck” and fastened to a peg, 6, at the bottom of the reel. As the reel revolves the heck slowly rises, and so causes the warp to be wound on the reel spirally, without overlapping. The heck is moved up and down a sufficient number of times to give the required number of ends in the warp, when the warp is cut off and unwound, and made up either in the form of a ball or a chain. The length of a warp is determined by the number of revolutions made by the mill from the commencement, until it is reversed at the other extremity.

FIG. 16.

SECTIONAL WARPING.

Sectional warping is a system chiefly employed in the production of coloured striped warps, from yarn previously dyed and sized in the hank, and subsequently wound upon warpers’ bobbins by a drum-winding machine. It is also sometimes employed in the production of grey warps for ball sizing. As its name implies, the operation consists of preparing a warp in sections, termed “cheeses,” each of which is a complete unit, and virtually a transverse section, of the full warp. When the required number of sections for a warp have been made, they are compressed between flanges side by side upon a mandril of a running-off machine, and their yarn run from them simultaneously on to a weaver’s beam. Sometimes a sectional warper works in conjunction with an automatic stop-motion similar to that of a beam warping machine, in which case bobbins are contained in a V-shaped creel. They also sometimes work without a stop-motion. In that case bobbins are contained in a curved creel similar to that employed in conjunction with a warping mill, whereby the threads are better under the observation of the operative warper, and broken threads may be more readily detected. One of the most important considerations in sectional warping is the production of sections of uniform diameter and length of yarn; otherwise, warp-ends would be of varying degrees of tension; also, waste of material would result from irregular lengths of yarn on the sections.

FIG. 17.

The principal parts of a well-known type of sectional warping machine are shown in Figs. 17, 18, and 19. Warp-ends, A, are withdrawn from a curved creel, and passed separately through needle eyes of a leasing heck, B, thence through a V-reed, D, over a tin measuring roller, F, and on to a section block, O, which is compressed between two flanges, N, O, upon a shaft, Q, by which it is turned. Flange N is removable to permit of a full section being replaced by an empty one. Another flange, 24, is keyed upon the section shaft, Q, and driven by means of friction bowls, 20, 20’, placed one on each side, and turned by driving shafts 16, 16', each of which contains a wide loose pulley, 17, 17', a narrow fast pulley, 18, 18', and a toothed wheel, 15, 15', which are in gear. Thus, if driving strap 19 is placed in a central position (as indicated) it runs on both loose pulleys, without effect; but if placed upon the fast pulley 18, it will turn the section forward, and wind yarn on the front, as shown, and if placed on fast pulley 18', it will turn a section backward, and wind yarn at the back. This arrangement enables sections to be made with one-half of a full repeat of a warp pattern, either alone or in addition to several repeats (provided the pattern is a symmetrical one), so that when all sections are placed in their proper position for running their yarn on to a weaver’s beam, two halves of a pattern will join together without a break. A uniform rate of winding yarn is maintained by causing friction driving bowls, 20, 20', to automatically recede from the section shaft at a pace exactly corresponding to that at which a section increases in diameter, thereby gradually retarding the velocity of the section shaft.

FIG. 18.

FIG. 19.

A presser roller, 12, carried at the end of a lever, 9, 11, fulcrumed on shaft 10, bears against yarn during winding, to wind it more compactly, and also to ensure uniformity of diameter of sections composing the same warp. During the winding of the first or “trial” section, the presser, which is suitably weighted, is free to recede at such pace as corresponds with the increasing diameter of that section; but for subsequent sections, the presser is under mechanical control, and may only recede at a prescribed pace, which should, however, exactly coincide with its recession during the formation of the first section. The movement of the presser is governed by means of a toothed quadrant or sector, 1, communicating with presser lever, 9, by a connecting rod, 6. The position of rod 6, in relation to the fulcrum 2 of the sector and the fulcrum 10 of the presser lever, determines the velocity at which the presser recedes. A cam, P, on the end of section shaft Q, imparts an intermittent rotary motion to a short vertical shaft, Y, by means of lever S, U, and pawl W. Surmounting shaft Y is a worm, Z, gearing with the teeth of sector 1 which slowly rises as a section revolves, thereby causing the presser to recede, at a prescribed pace. The number of revolutions of the section shaft is indicated upon a dial; also, the length of yarn wound is indicated upon a dial, by fingers operated by a train of wheels driven from worm G, on the end of tin measuring roller shaft F. The two indicators, therefore, serve as a check upon each other.

FIG. 20.

FIG. 21.

Section blocks are made in different widths from 3½ inches upwards. Some are constructed so as to permit of expansion and contraction, as shown in Fig. 20. Pressers are also constructed on a similar principle, as shown in Fig. 21.

SIZING.

The chief systems of sizing are slashing, dressing, ball-sizing, and hank-sizing.

The object of sizing is to strengthen the yarn by saturating it with a starchy substance, which lays the fibres, thus making it weave with less breakages. Other objects are to impart “feel” to the cloth, and to give it additional weight. For light sizing, in which the object is simply to strengthen the yarn, and not to increase its weight, only 10 to 15 per cent. is added to the weight. When 30 or 40 per cent. is added it is termed medium sizing, and for heavy sizing often 100 per cent. or more is added to the weight. The materials used for light sizing are: wheat flour, sago, farina or potato starch, rice flour or starch, maize.

Potato starch, or farina, is obtained from the tubers by reducing them to a pulp and mixing well with water. The water carries away the starch, and when allowed to stand the starch falls to the bottom of the vessel and the water can be drawn away. Farina is much used in all kinds of sizing, on account of its cheapness and the thickness of the paste it produces when boiled with water.

Sago is much used in light sizing, for which it is specially adapted. It is obtained from the pith of the sago palm, and made into flour by treating with water and drying on hot plates.

Maize is a starch obtained from the Indian corn, and is sometimes used for lightly sizing the finer counts of cotton yarns.

For light sizing it is not necessary to use anything but wheat flour, farina, or sago, and a small quantity of softening material, usually tallow or wax. Wheat flour is fermented before using by mixing it well with water (about equal weights of each) and leaving it for several weeks, occasionally stirring to keep the particles in suspension. When flour is fermented new bodies are formed, which have a powerful influence in preventing mildew. The fermenting cistern, 1 (Fig. 22), is usually a large vessel 8 feet by 4 feet by 4 feet, in which are two revolving “dashers,” C, to stir the flour and water when fermenting. Another similar cistern, 2, is used for storing called a “storage and diluting” cistern, into which the mixture is pumped after a few days, and left to further ferment. A force-pump, N, is used for pumping from this to the mixing cistern, 3, where the softening and weighting materials are added, after being boiled together in pan 4.

FIG. 22.

?
LARGER IMAGE

Softening materials are used to render the yarn more pliable. The articles mostly used for this purpose are tallow, wax, and soap, cocoanut and palm oil.

The following mixtures are suitable for light sizing. They can be made to give a greater or less percentage, according to the specific gravity of the mixture. For testing the specific gravity or density of the liquid, the Twaddell’s hydrometer is used. This instrument registers in degrees the density of the mixture, or the amount of matter in solution.

For light sizing—

Wheat flour

280

lbs.

Tallow

„

Another mixture is—

Sago

100

lbs.

Farina

100

„

Tallow

„

Soap

„

For sizing with sago, cocoanut oil is often used as a softening material. A mixture of these two gives as good a size as anything for pure sizing.

Another mixture used for fine counts is—

Farina

100

lbs.

Wax

„

Tallow

„

1 gall. water to 1 lb. farina.

Almost every manufacturer uses different proportions of ingredients. Many use wheat flour, farina, and sago mixed in various proportions, whilst a flour and farina mixture in the proportions of 2:1 is considered by some to give the best results. Farina and sago are also often mixed for light sizing in the proportion of two parts farina to one part sago. Wheat flour carries through better than farina or sago, and is therefore more generally used for the heavier kinds of sizing.

Any of these mixtures may be altered as regards strength, or otherwise, by increasing or diminishing their density. If a mixture twaddles 10 degrees at a given temperature, it may be strengthened for heavier cloths or higher picks by increasing the proportion of solid matter in the mixture until it twaddles 15 degrees at the same temperature.

For adding weight to the cloth china clay is the chief ingredient used. This material is found in deposits in Devonshire and Cornwall, and is used in large quantities for the purpose of weighting and filling cloth, more especially those manufactured for export to the Eastern markets.

For what is termed “medium” sizing, viz. adding about 30 to 50 per cent. to the weight of the cloth, the following materials are used in various proportions, the proportion given being an example—

Flour

100

lbs.

Clay

to 40 lbs.

Tallow

lbs.

Chloride of magnesium

gallon.

Chloride of zinc

„

It will be noticed here that chloride of magnesium and chloride of zinc are introduced along with the china clay. Chloride of magnesium is a very powerful softener as well as a weighting material, and one of its uses is to prevent the gritty feel which the addition of clay alone would give to the cloth. It has a great affinity for water, and has thus the power of attracting moisture to the cloth in which it is used. It is this which really constitutes its softening effect.

Chloride of zinc is used to prevent mildew, which is a species of vegetable growth which often occurs in sized cloth which has been left damp, or which attracts moisture.

As chloride of magnesium attracts moisture, it is necessary to use an antiseptic which will counteract the tendency of the cloth to mildew. Chloride of zinc possesses valuable properties as an antiseptic, and therefore it is often used where chloride of magnesium is used in the size as a softening and weighting material.

If china clay is used for medium sizing without using chloride of magnesium, it is necessary to greatly increase the proportion of tallow or other softeners in the mixture. Thus, for every 100 lbs. of flour, 40 lbs. clay, and perhaps 25 lbs. tallow would be used.

Chloride of calcium has a similar effect to chloride of magnesium, but is scarcely as powerful. It is used by many in light-sizing mixtures to prevent the yarn becoming too brittle.

For heavy sizing the proportions of clay and mineral ingredients are increased. In some classes of low shirtings, over 100 per cent. is added to the weight of the yarn. The adhesive material mostly used is wheat flour, as it carries the added materials better than farina or sago; but farina is sometimes used for sizing up to 100 per cent. Sometimes two parts clay to one of flour is used for very heavy sizing. For 100 per cent. sizing about the following proportions may be used:—

Flour

100

lbs.

Clay

130

„

Tallow

„

Chloride of magnesium

gallons

Chloride of zinc

„

Colouring matters are used in size to give the yarn any desired tinge. Blue is the most common, as it neutralizes the yellowness of the cloth given in heavy sizing. Only a very small quantity is required. Sometimes yellow is used to give a brownish appearance to American yarn, making it appear more like Egyptian. Numerous other materials are used for various purposes in sizing. “Gloy” has been found useful for strengthening warps for very heavily picked cloths.

Fig. 23 will show the principle of the slashing machine in its most usual form. The warpers’ beams are placed in the creel 1, at the back of the machine. In the diagram there are six beams, 1 to 6, so that if each one contains 500 ends there would be 3000 ends in the warp. The warp passes over roller A, and into the size-box. The small roller B in the size-box is of copper, and is called the immersion roller. The warp is passed under this, and its depth in the size mixture is regulated by it. The warp then passes between two pairs of rollers, C, D, and E, F (of which D and F are covered with flannel), to squeeze the surplus size from the yarn. The size is kept boiling in the size-box by the injection of steam. When the warp comes from the rollers E, F, it passes over a large drying cylinder, M, and, after passing almost completely round it, over a smaller cylinder, N, and then round the fan P and over guide-roller Q. The warp then passes through the dividing rods R (which divide the warp into the same portions that come from each warpers’ beam), thence over guide-roller S and tin measuring roller T, between drawing rollers U, V, and finally on to a weaver’s beam, Z. This end of the machine is called the “headstock,” and comprises the measuring mechanism, dividing rods, and winding-on arrangement.

FIG. 23.

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The position of the immersion roller in the size has some effect upon the amount of size retained on the warp, as by sinking the roller lower in the box the yarn will remain longer in the size, and will therefore absorb more. This roller is also mounted so that it can be lifted out of the size altogether when the machine is stopped. The larger cylinder is usually 6 feet to 7 feet diameter, and the smaller one about 4 feet diameter, and both are heated with steam.

Some machines have a revolving brush between the size-box and the cylinder. This brush is usually driven from the fan shaft, and its object is to lay the projecting fibres, and so strengthen the yarn. Brushes are only used in some fine-weaving districts, and not always there. The brush gives the threads a round, smooth feel, and prevents them sticking together. Under the brush which brushes the yarn a smaller brush is placed, running at a slower speed than the one above it; the lower brush is placed a short distance into the upper one, and serves the purpose of cleaning it as it revolves.

The marking mechanism in the slashing frame usually consists of a tin roller wheel, B (Fig. 24), driving the wheel D, called the “stud wheel”; a screw or worm, E, on this stud drives the bell wheel F. The marking hammer L is situated immediately above a vessel containing colouring matter, and is lifted by a cam, P, driven from the tin roller, and dropped suddenly on the warp, marking it to the required lengths.

The length between each mark is regulated by the wheels used. The tin roller wheel being the driver, if this is divided into the product of the stud wheel and bell wheel, it will give the number of revolutions of the tin roller for each mark, and this multiplied by the circumference of the roller will give the length of the mark. The formula will stand thus—

stud wheel × bell wheel × circumference of rollertin roller wheel=length of mark.

FIG. 24.

If the stud wheel contains 90 teeth, the bell wheel 45 teeth, the tin roller wheel 60, and the roller is 14·4 inches circumference, the length of the mark will be

90 × 45 × 14·460=972 inches

There are other marking motions in use for marking short lengths for dhooties and scarves of various kinds, some being constructed so as to mark scarves of two different lengths in succession—say one scarf is marked 2 yards long, and the next one 4, the two being repeated.

FIG. 25.

A “slow motion” arrangement is used for keeping the machine moving very slowly whilst the weaver’s beam is changed. If the machine is stopped completely, the warp becomes marked where it rests on the drying cylinders. Fig. 25 shows the principle of this arrangement. There are three pulleys, A, B, C, on the driving shaft D. Between the fast and loose pulleys A, C, the slow motion pulley B is placed. When the belt is moved from the fast pulley to the slow motion, the wheel F is set in motion and drives another wheel, G, and this, through the bevel wheels H, J, K, M, causes the catch O to drive the ratchet wheel P on the driven cone shaft T. As the motion of the driving catch O is slower than the cone T when driven by the fast pulley, the catch O will begin to work when the strap is moved from the fast pulley to the slow motion pulley, and the speed of the machine is reduced to the point where the catch O overtakes the driven cone T.

Hot-air drying has been employed in place of cylinder drying, but is not much used. In this system of drying the warp passes from the size-box to hot-air chambers. The air is heated with steam pipes and driven through the chambers by fans. Combinations of cylinder and hot-air drying have also been used, but with little success.

In a slasher sizing machine, yarn is withdrawn from back beams and finally wound upon a weaver’s beam at a uniform pace, notwithstanding the gradually increasing diameter of the latter as it fills with yarn. It follows, therefore, that the velocity of a beam must gradually diminish from the commencement of winding. In order to meet such requirement a beam is driven negatively by means of a frictional driving motion, one of which is shown in sectional elevation in Fig. 26. This motion consists of a tooth wheel, A, whose sides are extended beyond its proper teeth to form inner flanges, which latter are turned at right angles to form an outer rim. Two outer flanges, B, interlock with the rims of wheel A, as shown at C, so that wheel A and flanges B always revolve at the same velocity. Enclosed within each chamber between the inner flanges of A and outer flanges B is a sheet steel disc, D, encased within two flannel washers, E, and secured to a hub which rotates on a hollow beam shaft, O, in which is cut a channel or key-bed, R. The hubs of steel discs D being furnished with a key that enters the channel R, are free to slide upon shaft O, which they rotate at the same velocity. The hub of wheel A revolves freely upon the hubs of discs D; also, the hubs of flanges B revolve freely upon shaft O; therefore, by compressing the flanges and discs together, any degree of friction, within certain limits, may be induced. Pressure is applied to the flanges by means of a vertical lever, F, fulcrumed at G, and elbow lever J fulcrumed at K. A stud, I, in lever J bears against lever F with a force that may be regulated by means of an adjustable weight, L, N. On the inner end of shaft O, which receives one of the beam gudgeons, is a disc, P, furnished with a stud or peg, Q, to which is attached a rope or strap that encircles and grips one end of the weaver’s beam, which is thereby turned. As a beam becomes filled and its velocity diminishes, the slippage between discs D and the driving flanges increases, because the velocity of the driving flanges remains undiminished.

FIG. 26.

Automatic Supply of Size to a Sizing Machine.

There are numerous devices for the purpose of ensuring a continuous and automatic supply of size to the size-box of a slasher sizing machine. One of these is represented in Figs. 27 and 28. From the last mixing beck 3 (Fig. 22) size is pumped into a storage beck, 5, whence it is withdrawn and forced by a ram, N, along feed pipe Q, which is coiled within a steam-heated chamber, U. From the steam chamber it returns along pipe T, through regulating valve Z, and into the size-box, in a boiling state. Within a separate chamber of the size-box is a floating copper roller, X, connected at one end by means of rod Y to a tap which regulates the flow of size through valve Z, on the principle of a ball tap.

FIG. 27.

FIG. 28.

Scotch dressing is another system of applying size to the yarn. This is a much slower method than slashing, and is chiefly suitable for very fine yarns. In this machine the weaver’s beam is placed above an expanding reed, R (Fig. 29), and to prevent the ends being crowded the warper’s beams are divided, one-half the ends being placed at each end of the machine. The warp is passed through a pair of rollers, A E, the top one being very heavy. The lower roller of the pair is immersed some distance in the size, and takes the size up to the yarn. After emerging from the rollers or “squeezers,” the yarn passes through a revolving brush, B, and over a fan in a hot-air chamber, F, then through another brush, C, round a guide-roller through the expanding reed to the weaver’s beam. The opposite half of the machine is a duplicate of this. By this process the yarn is greatly strengthened. The brushing lays down all the projecting fibres, and makes the thread round, preventing any caking of the size on the threads. The production, of a machine of this kind, is much less than that of a slashing frame, as only about five beams a day can be dressed, whilst about fifteen beams could be slashed in the same time. Instead of the circular brush B, sometimes flat brushes are used. These are made to work on both sides, as shown at Fig. 30. The dotted lines show the movement of the brushes. The warp is brushed in the opposite direction to that in which it is moving.

FIG. 29.

FIG. 30.

FIG. 31.

Ball-warp Sizing.

Fig. 31 is a sectional elevation of a sizing machine for ball-warps. One or more warps, A, are placed upon cones, and their yarn guided over rollers, B, C, into a large size-box, 4, containing a series of rollers, between which yarn passes until it emerges at guide-roller G, when all excess of size is removed by rollers H, I. From the squeezing rollers, yarn is conducted to a drying machine (Fig. 32), consisting of a series of steam-heated cylinders arranged in two vertical zigzag rows, O, N, the outer rows of which are driven from vertical shafts containing a series of bevel wheels, Z, gearing with bevel wheels Y at one end of the cylinder shafts. By this means yarn is subjected to little tension, and its elasticity is better preserved. After drying, the warps are deposited in box crates, R, to be subsequently re-balled, ready for beaming or winding on to a weaver’s beam.

FIG. 32.

FIG. 33.

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LARGER IMAGE

FIG. 34.

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LARGER IMAGE

Beaming.

Beaming machines exist in great variety, but they may be classed under the heads of (1) press beaming, and (2) tension beaming machines. An example of the first-named type, as made by Butterworth and Dickinson, Ltd., is illustrated in Fig. 33. If beaming is accomplished from back beams prepared by a beam warping machine, a creel or stand capable of holding several beams is situated in the rear of the headstock of the beaming machine; but if beaming is from ball-warps, yarn from the latter is passed in a circuitous manner under and over tension and guide rollers A, B, for the purpose of tautening and separating warp-ends, which are finally passed through the dents of an expending comb, C, and on to a weaver’s beam. By causing weighted levers, D, to bear upon the beam-ends during winding, a hard and compact beam is made.

A tension beaming machine of the type known as a Yorkshire dressing machine, as made by Hattersley & Sons, is shown in Fig. 34. Yarn from a warp, A, or from several sections of warps, is conducted under and over the bars of a tension ladder, B, thence around dividing bars, C, between tension rollers, D, and finally through a wraith or coarse reed on to a weaver’s beam, E; but if Yorkshire dressing proper is adopted, warp-ends are passed through the dents of a reed in groups of two to four, and disposed according to pattern (if any) before passing on to a weaver’s beam ready for weaving in the loom. By means of stepped speed pulleys, F, G, the velocity of a beam may be retarded at intervals, to compensate for the gradually increasing diameter of a beam, and thereby maintain a uniform rate of winding.

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