Since jute yarns are comparatively thick, it is only the very finest yarns which contain 12 cuts per hank. The bulk of the yarn is made up into 6-cut hanks. If the yarn should be extra thick, even 6 cuts are too many to be combined, and one finds groups of 4 cuts, 3 cuts, 2 cuts, and even 1 cut. A convenient name for any group less than 12 cuts is a "mill-hank," because the number used is simply one of convenience to enable the mill-hank to be satisfactorily placed on the swift in the winding frame.
The reeling operation is useful in that it enables one to measure the length of the yarn; indeed, the operation of reeling, or forming the yarn into cuts and hanks, has always been used as the method of designating the count, grist or number of the yarn. We have already seen that the count of jute yarn is determined by the weight in lbs. of one spyndle (14,400 yds.).
For 8 lb. per spyndle yarn, and for other yarns of about the same count, it is usual to have provision for 24 spinning bobbins on the reel. As the reel rotates, the yarn from these 24 bobbins is wound round, say,
6 in. apart, and when the reel has made 120 revolutions, or 120 threads at each place from each bobbin, there will be 24 separate cuts of yarn on the reel. When 120 threads have been reeled as mentioned, a bell rings to warn the attendant that the cuts are complete; the reel is then stopped, and a "lease-band" is tied round each group of 120 threads.
A guide rod moves the thread guide laterally and slowly as the reeling operation is proceeding so that each thread or round may be in close proximity to its neighbour without riding on it, and this movement of the thread extends to approximately 6 in., to accommodate the 6 cuts which are to form the mill-hank.
Each time the reel has made 120 revolutions and the bell rings, the reeler ties up the several cuts in the width, so that when the mill-hank is complete, each individual cut will be distinct. In some case, the two threads of the lease-band instead of being tied, are simply crossed and recrossed at each cut, without of course breaking the yarn which is being reeled, although effectively separating the cuts. At the end of the operation (when the quantity of cuts for the mill-hank has been reeled) the ends of the lease-band are tied.
The object of the lease-band is for facilitating the operation of winding, and for enabling the length to be checked with approximate correctness.
When the reel has been filled with, say, twenty-four 6-cut hanks, there will evidently be 3 spyndles of yarn on the reel. The 24 mill-hanks are then slipped off the end of the reel, and the hanks taken to the bundling stool or frame. Here they, along with others of the same count, are made up into bundles which weigh from 54 lb. to 60 lb. according to the count of the yarn. Each bundle contains a number of complete hanks, and it is unusual to split a hank for the purpose of maintaining an absolutely standard weight bundle. Indeed, the bundles contain an even number of hanks, so that while there would be exactly 56 lb. per bundle of 7 lb. yarn, or 8 lb. yarn, there would be 60 lb in a bundle of 7-1/2 lb. yarn, and 54 lb. in a bundle of 9 lb. yarn.
The chief point in reeling is to ensure that the correct number of threads is in each cut, i.e. to obtain a "correct tell"; this ideal condition may be impracticable in actual work, but it is wise to approach it as closely as possible. Careless workers allow the reel to run on after one or more spinning bobbins are empty, and this yields what is known as "short tell." It is not uncommon to introduce a bell wheel with, say, 123 or 124 teeth, instead of the nominal 120 teeth, to compensate for this defect in reeling.
The actual spinning and twisting operations being thus completed, the yarns are ready to be combined either for more elaborate types of twist, or for the processes of cloth manufacture. In its simplest definition, a fabric consists of two series of threads interlaced in such way as to form a more or less solid and compact structure. The two series of threads which are interlaced receive the technical terms of warp and weft--in poetical language, warp and woof. The threads which form the length of the cloth constitute the warp, while the transverse threads are the weft.
The warp threads have ultimately to be wound or "beamed" on to a large roller, termed a weaver's beam, while the weft yarn has to be prepared in suitable shape for the shuttle. These two distinct conditions necessitate two general types of winding:
(a) Spool winding or bobbin winding for the warp yarns.
(b) Cop winding or pirn winding for the weft yarns.
For the jute trade, the bulk of the warp yarn is wound from the spinning bobbin on to large rolls or spools which contain from 7 to 8 lb. of yarn; the weft is wound from the spinning bobbin into cops which weigh approximately 4 to 8 ounces.
Originally all jute yarns for warp were wound on to flanged bobbins very similar to, but larger than, those which are at present used for the linen trade. The advent of the roll-winding machine marked a great advance in the method of winding warp yarns as compared with the bobbin winding method; indeed, in the jute trade, the latter are used only for winding from hank those yarns which have been bleached, dyed or similarly treated. Fig. 22 illustrates one of the modern bobbin winding machines for jute made by Messrs. Charles Parker, Sons & Co., Dundee. The finished product is illustrated by two full bobbins on the stand and close to a single empty bobbin. There are also two full bobbins in the winding position, and several hanks of yarn on the swifts. Each bobbin is driven by means of two discs, and since the drive is by surface contact between the discs and the bobbin, an almost constant speed is imparted to the yarn throughout the process. An automatic stop motion is provided for each bobbin; this apparatus lifts the bobbin clear of the discs when the bobbin is filled as exemplified in the illustration.
The distance between the flanges of the bobbin is, obviously, a fixed one in any one machine, and the diameter over the yarn is limited. On the other hand, rolls may be made of varying widths and any suitable diameter. And while a bobbin holds about 2 lb. of yarn, a common size of roll weighs, as already stated, from 7 to 8 lb. Such a roll measures, about 9 in. long and 8 in. diameter; hence for 8 lb. yarn, the roll capacity is 14,400 yards.
Rolls very much larger than the above are made on special machines adopted to wind about six rolls as shown in Fig. 23. It is built specially for winding heavy or thick yarns into rolls of 15 in. diameter and 14 in. length, and this particular machine is used mostly by rope makers and carpet manufacturers. One roll only is shown in the illustration, and it is winding the material from a 10 in. x 5 in. rove bobbin. The rove is drawn forward by surface or frictional contact between the roll itself and a rapidly rotating drum. The yarn guide is moved rapidly from side to side by means of the grooved cam on the left, the upright lever fulcrumed near the floor, and the horizontal rod which passes in front of the rolls and upon which are fixed the actual yarn guides. This rapid traverse, combined with the rotation of the rolls, enables the yarn to be securely built upon a paper or wooden tube; no flanges are required, and hence the initial cost as well as the upkeep of the foundations for rolls is much below that for bobbins.
FIG. 22 BOBBIN WINDING MACHINE WITH HANKS
Precisely the same principles are adopted for winding the ordinary 9 in. x 8 in. or 8 in. x 7 in. rolls for the warping and dressing departments. These rolls are made direct from the yarn on spinning bobbins, but the machines are usually double-sided, each side having two tiers; a common number of spools for one machine is 80.
The double tier on each side is practicable because of the small space required for the spinning bobbins. When, however, rolls are wound from hank, as is illustrated in Fig. 24, and as practised in several foreign countries even for grey yarn, one row only at each side is possible. Both types are made by each machine maker, the one illustrated in Fig. 24 being the product of Messrs. Charles Parker, Sons & Co., Dundee.
In all cases, the yarns are built upon tubes as mentioned, the wooden ones weighing only a few ounces and being practically indestructible, besides being very convenient for transit; indeed it looks highly probable that the use of these articles will still further reduce the amount of yarn exported in bundle form.
FIG. 23 ROLL WINDER FOR LARGE ROLLS
The machine illustrated in Fig. 24, as well as those by other makers, is very compact, easily adjustable to wind different sizes of rolls, can be run at a high speed, and possesses automatic stop motions, one for each roll.
A full roll and a partially-filled roll are clearly seen. A recent improvement in the shape of a new yarn drag device, and an automatic stop when the yarn breaks or the yarn on the bobbin is exhausted, has just been introduced on to the Combe-Barbour frame.
FIG. 24 ROLL WINDING MACHINE (FROM HANKS)
Weft Winding. A few firms wind jute weft yarn from the spinning bobbins on to pirns (wooden centres). The great majority of manufacturers, however, use cops for the loom shuttles. The cops are almost invariably wound direct from the spinning bobbins, the exception being coloured yarn which is wound from hank. There are different types of machines used for cop winding, but in every case the yarn is wound upon a bare spindle, and the yarn guide has a rapid traverse in order to obtain the well-known cross-wind so necessary for making a stable cop. The disposition of the cops in the winding operation is vertical, but while in some machines the tapered nose of the cop is in the high position and the spinning bobbin from which the yarn is being drawn is in the low position, in other machines these conditions are opposite. Thus, in the cop winding frame made by Messrs. Douglas Fraser & Sons, Ltd., Arbroath, and illustrated in Fig. 25, the spinning bobbins are below the cops, the tapered noses of the latter are upwards in their cones or shapers, and the yarn guides are near the top of the machine. This view shows about three-fourths of the full width of a 96-spindle machine, 48 spindles on each side, two practically full-length cops and one partially built. The illustration in Fig. 26 is the above-mentioned opposite type, and the one most generally adopted, with the spinning bobbins as shown near the top of the frame, the yarn guides in the low position, and the point or tapered nose of the cop pointing downwards. Six spindles only appear in this view, which represents the machine made by Messrs. Urquhart, Lindsay & Co., Ltd., Dundee, but it will be understood that all machines are made as long as desired within practicable and economic limits.
The spindles of cop machines are gear driven as shown clearly in Fig. 26; the large skew bevel wheels are keyed to the main shaft, while the small skew bevel wheels are loose on their respective spindles. The upper face of each small skew bevel wheel forms one part of a clutch; the other part of the clutch is slidably mounted on the spindle. When the two parts of the clutch are separated, as they are when the yarn breaks or runs slack, when it is exhausted, or when the cop reaches a predetermined length, the spindle stops; but when the two parts of the clutch are in contact, the small skew bevel wheel drives the clutch, the latter rotates the spindle, and the spindle in turn draws forward the yarn from the bobbin, and in conjunction with the rapidly moving yarn guide and the inner surface of the cone imparts in rapid succession new layers on the nose of the cop, and thus the formed layers of the latter increase the length proportionately to the amount of yarn drawn on, and the partially completed cop moves slowly away from its cup or cone until the desired length is obtained when the spindle is automatically stopped and the winding for that particular spindle ceases. Cops may be made of any length and any suitable diameter; a common size for jute shuttle is 10 in. long, and 1-5/8 in. diameter, and the angle formed by the two sides of the cone is approximately 30 degrees.
There are a few distinct methods of preparing warp threads on the weaver's beam. Stated briefly, the chief methods are--
1. The warp is made in the form of a chain on a warping mill,
and when the completed chain is removed from the mill it is
transferred on to the weaver's beam.
2. The warp is made in the form of a chain on a linking
machine, and then beamed on to a weaver's beam.
3. The warp yarns are wound or beamed direct from the large
cylindrical "rolls" or "spools" on to a weaver's beam.
4. The warp yarns are starched, dried and beamed
simultaneously on to a weaver's beam.
The last method is the most extensively adapted; but we shall describe the four processes briefly, and in the order mentioned.
For mill warping, as in No. 1 method, from 50 to 72 full spinning bobbins are placed in the bank or creel as illustrated to the right of each large circular warping mill in Fig. 27. The ends of the threads from these bobbins are drawn through the eyes of two leaves of the "heck," and all the ends tied together. The heck, or apparatus for forming what is known as the weaver's lease, drawer's lease, or thread-by-thread lease, is shown clearly between the bobbin bank and the female warper in the foreground of the illustration. The heck is suspended by means of cords, or chains, and so ranged that when the warping mill is rotated in one direction the heck is lowered gradually between suitable slides, while when the mill is rotated in the opposite direction the heck is raised gradually between the same slides. These movements are necessary in order that the threads from the bobbins may be arranged spirally round the mill and as illustrated clearly on all the mills in the figure. The particular method of arranging the ropes, or the gearing if chains are used, determines the distance between each pair of spirals; a common distance is about 1-1/2 in. There are about 42 spirals or rounds on the nearest mill in Fig. 27, and this number multiplied by the circumference of the mill represents the length of the warp.
FIG. 27 A ROW OF MODERN WARPING MILL
At the commencement, the heck is at the top, and when the weaver's lease has been formed on the three pins near the top of the mill with the 50 to 72 threads (often 56), the mill is rotated by means of the handle and its connections shown near the bottom of the mill. As the mill rotates, the heck with the threads descends gradually and thus the group of threads is disposed spirally on the vertical spokes of the mill until the desired length of the warp is reached. A beamer's lease or "pin lease" is now made on the two lower pegs; there may be two, three, four or more threads in each group of the pin lease; a common number is 7 to 9. When this pin lease has been formed, one section of the warp has been made, the proportion finished being (50 to 72)/x where x is the total number of threads required for the cloth. The same kind of lease must again be made on the same two pins at the bottom for the beginning of the next section of 50 to 72 threads, and the mill rotated in the opposite direction in order to draw up the heck, and to cause the second group of 50 to 72 threads to be arranged spirally and in close touch with the threads of the first group. When the heck reaches the top of the mill, the single-thread lease is again made, all the threads passed round the end pin, and then all is ready for repeating the same two operations until the requisite number of threads has been introduced on to the mill. If it is impossible to accommodate all the threads for the cloth on the mill, the warp is made in two or more parts or chains. It will be noticed that the heck for the nearest mill is opposite about the 12th round of threads from the bobbin, whereas the heck for the second mill is about the same distance from the top. A completed warp or chain is being bundled up opposite the third mill. When the warp is completed it is pulled off the mill and simultaneously linked into a chain.
A very similar kind of warp can be made more quickly, and often better, on what is termed the linking machine mentioned in No. 2 method. Such a machine is illustrated in Fig. 28, and the full equipment demands the following four distinct kinds of apparatus--a bank capable of holding approximately 300 spools, a frame for forming the weaver's lease and the beamer's lease, machine for drawing the threads from the spools in the bank and for measuring the length and marking the warp at predetermined intervals, and finally the actual machine which links the group of threads in the form of a chain.
In Fig. 28 part of the large bank, with a few rows of spools, is shown in the extreme background. The two sets of threads, from the two wings of the bank, are seen distinctly, and the machine or frame immediately in front of the bank is where the two kinds of lease are made when desired, i.e. at the beginning and at the end of the warp. Between this leasing frame and the linking machine proper, shown in the foreground, is the drawing, measuring and marking machine. Only part of this machine is seen--the driving pulleys and part of the frame adjoining them. All these frames and machines are necessary, but the movements embodied in them, or the functions which they perform, are really subsidiary to those of the linker shown in the foreground of Fig. 28.
IG. 28 POWER CHAIN OF WARP LINKING MACHINE
Although the linking machine is composed of only a few parts, it is a highly-ingenious combination of mechanical parts; these parts convert the straight running group of 300 threads into a linked chain, and the latter is shown distinctly descending from the chute on to the floor in the figure. Precisely the same kind of link is made by the hand wrappers when the warps indicated in Fig. 27 are being withdrawn from the mills. Two completed chains are shown tied up in Fig. 28, and a stock of rolls or spools appear against the wall near the bank.
The completed chain from the warping mill or the linking machine is now taken to the beaming frame, and after the threads, or rather the small groups of threads, in the pin lease have been disposed in a kind of coarse comb or reed, termed an veneer or radial, and arranged to occupy the desired width in the veneer, they are attached in some suitable way to the weaver's beam. The chain is held taut, and weights applied to the presser on the beam while the latter is rotated. In this way a solid compact beam of yarn is obtained. The end of the warp--that one that goes on to the beam last--contains the weaver's lease, and when the completed beam is removed from the beaming or winding-on frame, this single-thread lease enables the next operative to select the threads individually and to draw the threads, usually single, but sometimes in pairs, in which case the lease would be in pairs, through the eyes of the camas or HEALDS, or to select them for the purpose of tying them to the ends of the warp in the loom, that is to the "thrum" of a cloth which has been completed.
Instead of first making a warp or chain on the warping mill, or on the linking machine, and then beaming such warp on to the weaver's beam or loom beam as already described, two otherwise distinct processes of warping and beaming may be conducted simultaneously. Thus, the total number of threads required for the manufacture of any particular kind of cloth--unless the number of threads happens to be very high--may be wound on to the loom beam direct from the spools. Say, for example, a warp was required to be 600 yards long, and that there should be 500 threads in all. Five hundred spools of warp yarn would be placed in the two wings of a V-shaped bank, and the threads from these spools taken in regular order, and threaded through the splits or openings of a reed which is placed in a suitable position in regard to the winding-on mechanism. Some of the machines which perform the winding-on of the yarn are comparatively simple, while others are more or less complicated. In some the loom beam rotates at a fixed number of revolutions per minute, while in others the beam rotates at a gradually decreasing number of revolutions per minute. One of the latter types made by MESSRS Urquhart, Lindsay & Co., Ltd., Dundee, is illustrated in Fig. 29, and the mechanism displayed is identical with that employed for No. 4 method of preparing warps.
The V-shaped bank with its complement of spools (500 in our example) would occupy a position immediately to the left of Fig. 29. The threads would pass through a reed and then in a straight wide sheet between the pair of rollers, these parts being contained in the supplementary frame on the left. A similar frame appears on the extreme right of the figure, and this would be used in conjunction with another V-shaped bank, not shown, but which would occupy a position further to the right, i.e. if one bank was not large enough to hold the required number of spools. The part on the extreme right can be ignored at present.
The threads are arranged in exactly the same way as indicated in Fig. 28 from the bank to the reed in front of the rollers in Fig. 29, and on emerging from the pair of rollers are taken across the stretch between the supplementary frame and the main central frame, and attached to the weavers beam just below the pressing rollers. It may be advisable to have another reed just before the beam, so that the width occupied by the threads in the beam may be exactly the same as the width between the two flanges of the loom beam.
FIG. 29 WINDING-ON OR DRY BEAMING MACHINE
The speed of the threads is determined by the surface speed of the two rollers in the supplementary frame, the bottom roller being positively driven from the central part through the long horizontal shaft and a train of wheels caged in as shown. The loom beam, which is seen clearly immediately below the pressing rollers, is driven by friction because the surface speed of the yarn must be constant; hence, as the diameter over the yarn on the beam increases, the revolutions per minute of the beam must decrease, and a varying amount of slip takes place between the friction-discs and their flannels.
As the loom beam rotates, the threads are arranged in layers between the flanges of the loom beam. Thus, the 500 threads would be arranged side by side, perhaps for a width of 45 to 46 in., and bridging the gap between the flanges of the beam; the latter is thus, to all intents and purposes, a very large bobbin upon which 500 threads are wound at the same time, instead of one thread as in the ordinary but smaller bobbin or reel. It will be understood that in the latter case the same thread moves from side to side in order to bridge the gap, whereas in the former case each thread maintains a fixed position in the width.
The last and most important method of making a warp, No. 4 method, for the weaver is that where, in addition to the simultaneous processes of warping and beaming as exemplified in the last example, all the threads are coated with some suitable kind of starch or size immediately they reach the two rollers shown in the supplementary frame in Fig. 29. The moistened threads must, however, be dried before they reach the loom beam. When a warp is starched, dried and beamed simultaneously, it is said to be "dressed."
In the modern dressing machine, such as that illustrated in Fig. 30, there are six steam-heated cylinders to dry the starched yarns before the latter reach the loom beams. Both banks, or rather part of both, can be seen in this view, from which some idea will be formed of the great length occupied. Several of the threads from the spools in the left bank are seen converging towards the back reed, then they pass between the two rollers--the bottom one of which is partially immersed in the starch trough--and forward to the second reed. After the sheet of threads leaves the second reed, it passes partially round a small guide roller, then almost wholly round each of three cylinders arranged °o°, and finally on to the loom beam. Each cylinder is 4 feet diameter, and three of them occupy a position between the left supplementary frame, and the central frame in Fig. 29, while the remaining three cylinders are similarly disposed between the central frame and the supplementary frame of the right in the same illustration.
The number of steam-heated cylinders, and their diameter, depend somewhat upon the type of yarn to be dressed, and upon the speed which it is desired to run the yarn. A common speed for ordinary-sized jute is from 18 to 22 yards per minute.
FIG. 30 A MODERN YARN DRESSING MACHINE WITH SIX STEAM-HEATED CYLINDERS
A different way of arranging the cylinders is exemplified in Fig. 31. This view, which illustrates a machine made by Messrs. Charles Parker, Sons & Co., Dundee, has been introduced to show that if the warps under preparation contain a comparatively few threads, or if the banks are made larger than usual, two warps may be dressed at the same time. In such a case, three cylinders only would be used for each warp, and the arrangement would be equivalent to two single dressing machines. The two weaver's beams, with their pressing rollers, are shown plainly in the centre of the illustration. Some machines have four cylinders, others have six, while a few have eight. A very similar machine to that illustrated in Fig. 31 is made so that all the six cylinders may be used to dry yarns from two banks, and all the yarns wound on to one weaver's beam, or all the yarns may be wound on to one of the beams in the machine in Fig. 31 if the number of threads is too many for one bank.
FIG. 31 DRESSING MACHINE FOR PREPARING TWO WARPS SIMULTANEOUSLY
Suppose it is desired to make a warp of 700 threads instead of 500, as in the above example; then 350 spools would be placed in each of the two banks, the threads disposed as already described to use as much of the heating surface of the cylinder as possible, and one sheet of threads passed partially round what is known as a measuring roller. Both sheets of threads unite into one sheet at the centre of the machine in Fig. 31, and pass in this form on to one of the loom beams.
It has already been stated that the lower roller in the starch box is positively driven by suitable mechanism from the central part of the machine, Fig. 29, while the upper roller, see Fig. 30, is a pressing roller and is covered with cloth, usually of a flannel type. Between the two rollers the sheet of 350 threads passes, becomes impregnated with the starch which is drawn up by the surface of the lower roller, and the superfluous quantity is squeezed out and returns to the trough, or joins that which is already moving upwards towards the nip of the rollers. The yarn emerges from the rollers and over the cylinders at a constant speed, which may be chosen to suit existing conditions, and it must also be wound on to the loom beam at the same rate. But since the diameter of the beam increases each revolution by approximately twice the diameter of the thread, it is necessary to drive the beam by some kind of differential motion.
The usual way in machines for dressing jute yarns is to drive the beam support and the beam by means of friction plates. A certain amount of slip is always taking place--the drive is designed for this purpose--and the friction plates are adjusted by the yarn dresser during the operation of dressing to enable them to draw forward the beam, and to slip in infinitesimal sections, so that the yarn is drawn forward continuously and at uniform speed.
During the operation, the measuring roller and its subsequent train of wheels and shafts indicates the length of yarn which has passed over, also the number of "cuts" or "pieces" of any desired length; in addition, part of the measuring and marking mechanism uses an ink-pad to mark the yarn at the end of each cut, such mark to act as a guide for the weaver, and to indicate the length of warp which has been woven. Thus if the above warp were intended to be five cuts, each 120 yards, or 600 yards in all, the above apparatus would measure and indicate the yards and cuts, and would introduce a mark at intervals of 120 yards on some of the threads. And all this is done without stopping the machine. At the time of marking, or immediately before or after, just as desired, a bell is made to ring automatically so that the attendant is warned when the mark on the warp is about to approach the loom beam. This bell is shown in Fig. 29, near the right-hand curved outer surface of the central frame.
As in hand warping or in linking, a single-thread lease is made at the end of the desired length of warp, or else what is known as a pair of "clasp-rods" is arranged to grip the sheet of warp threads.
After the loom beam, with its length of warp, has been removed from the machine, the threads are either drawn through the eyes or mails of the cambs (termed gears, healds or heddles in other districts) and through the weaving reed, or else they are tied to the ends of the threads of the previous warp which, with the weft, has been woven into cloth. These latter threads are still intact in the cambs and reed in the loom.
If all the threads of the newly-dressed warp can be tied on to the ends of the warp which has been woven, it is only necessary, when the tying-on process is completed, to rotate the loom beam slowly, and simultaneously to draw forward the threads until all the knots have passed through the cambs and the reed, and sufficiently far forward to be clear of the latter when it approaches its full forward, or beating up, position during the operation of weaving.
If, on the other hand, the threads of the newly-dressed, or newly-beamed, warp had to be drawn-in and reeded, these operations would be performed in the drawing-in and reeding department, and, when completed, the loom beam with its attached warp threads, cambs and reed, would be taken bodily to the loom where the "tenter," "tackler" or "tuner" adjusts all the parts preparatory to the actual operation of weaving. The latter work is often termed "gaiting a web."
There is a great similarity in many of the operations of weaving the simpler types of cloth, although there may be a considerable difference in the appearance of the cloths themselves. In nearly all the various branches of the textile industry the bulk of the work in the weaving departments of such branches consists of the manufacture of comparatively simple fabrics. Thus, in the jute industry, there are four distinct types of cloth which predominate over all others; these types are known respectively as hessian, bagging, tarpauling and sacking. In addition to these main types, there are several other simple types the structure of which is identical with one or other of the above four; while finally there are the more elaborate types of cloth which are embodied in the various structures of carpets and the like.
It is obviously impossible to discuss the various makes in a work of this kind; the commoner types are described in Jute and Linen Weaving Calculations and Structure of Fabrics; and the more elaborate ones, as well as several types of simple ones, appear in Textile Design: Pure and Applied, both by T. Woodhouse and T. Milne.
Six distinct types of jute fabrics are illustrated in Fig. 32. The technical characteristics of each are as follows--
FIG. 32 SIX DISTINCT KINDS OF TYPICAL JUTE FABRICS
H.--An ordinary "HESSIAN" cloth made from comparatively fine single warp and single weft, and the threads interlaced in the simplest order, termed "plain weave." A wide range of cloths is made from the scrims or net-like fabrics to others more closely woven than that illustrated.
B.--A "BAGGING" made from comparatively fine single warp arranged in pairs and then termed "double warp." The weft is thick, and the weave is also plain.
T.--A "TARPAULING" made from yarns similar to those in bagging, although there is a much wider range in the thickness of the weft. It is a much finer cloth than the typical bagging, but otherwise the structures are identical.
S.--A striped "SACKING" made from comparatively fine warp yarns, usually double as in bagging, but occasionally single, with medium or thick weft interwoven in 3-leaf or 4-leaf twill order. The weaves are shown in Fig. 33.
C.--One type of "CARPET" cloth made exclusively from two-ply or two-fold coloured warp yarns, and thick black single weft yarns. The threads and picks are interwoven in two up, two down twill, directed to right and then to left, and thus forming a herring-bone pattern, or arrow-head pattern.
P.-An uncut pile fabric known as "BRUSSELLETTE." The figuring warp is composed of dyed and printed yarns mixed to form an indefinite pattern, and works in conjunction with a ground warp and weft. The weave is again plain, although the structure of the fabric is quite different from the other plain cloths illustrated. The cloth is reversible, the two sides being similar structure but differing slightly in colour ornamentation.
As already indicated, there are several degrees of fineness or coarseness in all the groups, particularly in the types marked H, B, T and S. The structure or weave in all varieties of any one group is constant and as stated.
All the weaves are illustrated in the usual technical manner in Fig. 33, and the relation between the simplest of these weaves and the yarns of the cloth is illustrated in Fig. 34. In Fig. 33, the unit weaves in A, B, C, D, E and F are shown in solid squares, while the repetitions of the units in each case are represented by the dots.
FIG. 33 POINT-PAPER DESIGNS SHOWING WEAVES FOR VARIOUS CLOTHS
IG. 34 DIAGRAMMATIC VIEWS OF THE STRUCTURE OF PLAIN CLOTH
A is the plain weave, 16 units shown, and used for fabrics H and P, Fig. 32.
B is the double warp plain wave, 8 units shown, and shows the method of interlacing the yarns h patterns B and T, Fig. 32. When the warp is made double as indicated in weave B, the effect in the cloth can be produced by using the mechanical arrangements employed for weave A. Hence, the cloths H, B and T can be woven without any mechanical alteration in the loom.
C is the 3-leaf double warp sacking weave and shows 4 units; since each pair of vertical rows of small squares consists of two identical single rows, they may be represented as at D. The actual structure of the cloth S in Fig. 32 is represented on design paper at C, Fig. 33.
D is the single warp 3-leaf sacking weave, 4 units shown, but the mechanical parts for weaving both C and D remain constant.
E is the double warp 4-leaf sacking, 2 units shown, while
F is the single warp 4-leaf sacking, 4 units shown.
The patterns or cloths for E and F are not illustrated.
G is a "herring-bone" design on 24 threads and 4 picks, two units shown. It is typical of the pattern represented at C, Fig. 32, and involves the use of 4 leaves in the loom.
The solid squares in weave A, Fig. 33, are reproduced in the left-hand bottom corner of Fig. 34. A diagrammatic plan of a plain cloth produced by this simple order of interlacing is exhibited in the upper part by four shaded threads of warp and four black picks of weft (the difference is for distinction only). The left-hand intersection shows one thread interweaving with all the four picks, while the bottom intersection shows all the four threads interweaving with one pick. The two arrows from the weave or design to the thread and pick respectively show the connection, and it will be seen that a mark (solid) on the design represents a warp thread on the surface of the cloth, while a blank square represents a weft shot on the surface, and vice versa.
A weaving shed full of various types of looms, and all driven by belts from an overhead shaft, is illustrated in Fig. 35. The loom in the foreground is weaving a 3-leaf sacking similar to that illustrated at S, Fig. 32. while the appearance of a full weaver's warp beam is shown distinctly in the second loom in Fig. 35. There are hundreds of looms in this modern weaving shed.
FIG. 35 WEAVING SHED WITH BELT-DRIVEN LOOMS
During the operation of weaving, the shuttle, in which is placed a cop of weft, similar to that on the cop winding machine in Fig. 25, and with the end of the weft threaded through the eye of the shuttle, is driven alternately from side to side of the cloth through the opening or "shed" formed by two layers of the warp. The positions of the threads in these two layers are represented by the designs, see Fig. 33, and while one layer occupies a high position in the loom the other layer occupies a low position. The threads of the warp are placed in these two positions by the leaves of the camb (termed healds and also gears in other districts) and it is between these two layers that the shuttle passes, forms a selvage at the edge each time it makes a journey across, and leaves a trail or length of weft each journey. The support or lay upon which the shuttle travels moves back to provide room for the shuttle to pass between the two layers of threads, and after the shuttle reaches the end of each journey, the lay with the reed comes forward again, and thus pushes successively the shots of weft into close proximity with the ones which preceded.
FIG. 36 LOOMS DRIVEN WITH INDIVIDUAL MOTORS
The order of lifting and depressing the threads of the warp is, as already stated, demonstrated on the design paper in Fig. 33, and the selected order determines, in the simplest cases, the pattern on the surface of the cloth when the warp and weft yarns are of the same colour. A great diversity of pattern can be obtained by the method of interlacing the two sets of yarn, and a still greater variety of pattern is possible when differently-coloured threads are added to the mode of interlacing.
To illustrate the contrast in the general appearance of a weaving shed in which all the looms are driven by belts from overhead shafting as in Fig. 35, and in a similar shed in which all the looms are individually driven by small motors made by the English Electric Co., Ltd. we introduce Fig. 36. This particular illustration shows cotton weaving shed, but precisely the same principle of driving is being adopted in many jute factories.
A great variety of carpet patterns of a similar nature to that illustrated at C, Fig. 32, can be woven in looms such as those illustrated in Fig. 35; indeed, far more elaborate patterns than that mentioned and illustrated are capable of being produced in these comparatively simple looms. When, however, more than 4 leaves are required for the weaving of a pattern, a dobby loom, of the nature of that shown in Fig. 37, is employed; this machine is made by Messrs. Charles Parker, Sons & Co., Ltd., Dundee. The dobby itself, or the apparatus which lifts the leaves according to the requirements of the design, is fixed on the upper part of the frame-work, and is designed to control 12 leaves, that is, it operates 12 leaves, each of which lifts differently from the others.
A considerable quantity of Wilton and Brussels carpets is made from jute yarns, and Fig. 38 illustrates a loom at work on this particular branch of the trade. The different colours of warp for forming the pattern me from small bobbins in the five frames at the back of the loom (hence the term 5-frame Brussels or Wilton carpet) and the ends passed through "mail eyes" and then through the reed. The design is cut on the three sets of cards suspended in the cradles in the front of the loom, and these cards operate on the needles of the jacquard machine to raise those colours of yarn which e necessary to produce the colour effect in the cloth t correspond with the colour effect on the design paper made by the designer. This machine weaves the actual Brussels and Wilton fabrics, and these cloths are quite different from that illustrated at P, Fig. 32. In both fabrics, however, ground or foundation warps are required. It need hardly be said that there is a considerable difference between the two types of cloth, as well as between the designs and the looms in which they are woven.[2]
[Footnote 2: For structure of carpets, see pp. 394-114, Textile Design: Pure and Applied, by T. Woodhouse and T. Milne.]
FIG. 38 BRUSSELS CARPET JACQUARD LOOM
In the weaving department there are heavy warp beams to be placed in the looms, and in the finishing department there are often heavy rolls of cloth to be conveyed from the machines to the despatch room. Accidents often happen when these heavy packages, especially the warp beams, are being placed in position. In order to minimize the danger to workpeople and to execute the work more quickly and with fewer hands, some firms have installed Overhead Runway Systems, with suitable Lifting Gear, by means of which the warp beams are run from the dressing and drawing-in departments direct to the looms, and then lowered quickly and safely into the bearings. Such means of transport are exceedingly valuable where the looms are set close to each other and where wide beams are employed; indeed, they are valuable for all conditions, and are used for conveying cloth direct from the looms as well as warp beams to the looms. Fig. 39 shows the old wasteful and slow method of transferring warp beams from place to place, while Fig. 40 illustrates the modern and efficient method. The latter figure illustrates one kind of apparatus, supplied by Messrs. Herbert Morris, Ltd., Loughborough, for this important branch of the industry.
The finishing touches are added to the cloth after the latter leaves the loom. The first operation is that of inspecting the cloth, removing the lumps and other undesirables, as well as repairing any damaged or imperfect parts. After this, the cloth is passed through a cropping machine the function of which is to remove all projecting fibres from the surface of the cloth, and so impart a clean, smart appearance. It is usual to crop both sides of the cloth, although there are some cloths which require only one side to be treated, while others again miss this operation entirely.
A cropping machine is shown in the foreground of Fig. 41, and in this particular case there are two fabrics being cropped or cut at the same time; these happen to be figured fabrics which have been woven in a jacquard loom similar to that illustrated in Fig. 38. The fabrics are, indeed, typical examples of jute Wilton carpets. The illustration shows one of the spiral croppers in the upper part of the machine in Fig. 41. Machines are made usually with either two or four of such spirals with their corresponding fixed blades.
FIG. 41 CROPPING MACHINE AT WORK
The cloth is tensioned either by threading it over and under a series of stout rails, or else between two in a specially adjustable arrangement by means of which the tension may be varied by rotating slightly the two rails so as to alter the angle formed by the cloth in contact with them. This is, of course, at the feed side; the cloth is pulled through the machine by three rollers shown distinctly on the right in Fig. 42. This view illustrates a double cropper in which both the spirals are controlled by one belt. As the cloth is pulled through, both sides of it are cropped by the two spirals.[3] When four spirals are required, the frame is much wider, and the second set of spirals is identical with those in the machines illustrated.
FIG. 42 DOUBLE CROPPING MACHINE
[Footnote 3: For a full description of all finishing processes, see The Finishing of Jute and Linen Fabrics, by T. Woodhouse. (Published by Messrs. Emmott & Co., Ltd., Manchester.)]
The cropped cloth is now taken to the clamping machine, and placed on the floor on the left of the machine illustrated in Fig. 43, which represents the type made by Messrs. Charles Parker, Sons &, Co., Dundee. The cloth is passed below a roller near to the floor, then upwards and over the middle roller, backwards to be passed under and over the roller on the left, and then forwards to the nip of the pulling rollers, the bottom one of which is driven positively by means of a belt on the pulleys shown. While the cloth is pulled rapidly through this machine, two lines of fine jets spray water on to the two sides of the fabric to prepare it for subsequent processes in which heat is generated by the nature of the finishing process. At other times, or rather in other machines, the water is distributed on the two sides of the cloth by means of two rapidly rotating brushes which flick the water from two rollers rotating in a tank of water at a fixed level. In both cases, both sides of the fabric are "damped," as it is termed, simultaneously. The damped fabric is then allowed to lie for several hours to condition, that is, to enable the moisture to spread, and then it is taken to the calender.
The calenders for jute almost invariably contain five different rollers, or "bowls," as they are usually termed; one of these bowls, the smallest diameter one, is often heated with steam. A five-bowl calender is shown on the extreme right in Fig. 41, and in the background, while a complete illustration of a modern 5-bowl calender, with full equipment, and made by Messrs. Urquhart, Lindsay & Co., Ltd., Dundee, appears in Fig. 44.
The cloth is placed on the floor between the two distinct parts of the calender, threaded amongst the tension rails near the bottom roller or bowl, and then passed over two or more of the bowls according to the type of finish desired. For calender finish, the bowls flatten the cloth by pressing out the threads and picks, so that all the interstices which appear in most cloths as they leave the loom, and which are exaggerated in the plan view in Fig. 34, are eliminated by this calendering action. The cloth is then delivered at the far side of the machine in Fig. 44. If necessary, the surface speed of the middle or steam-heated roller may differ from the others so that a glazed effect--somewhat resembling that obtained by ordinary ironing--is imparted to the surface of the fabric. The faster moving roller is the steam-heated one. For ordinary calender finish, the surface speed of all the rollers is the same.
Another "finish" obtained on the calender is known as "chest finish" or "round-thread finish." In this case, the whole length of cloth is wound either on to the top roller, or the second top one, Fig. 44, and while there is subjected to the degree of pressure required; the amount of pressure can be regulated by the number of weights and the way in which the tension belt is attached to its pulley. The two sets of weights are seen clearly on the left in Fig. 44, and these act on the long horizontal levers, usually to add pressure to the dead weight of the top roller, but occasionally, for very light finishes, to decrease the effective weight of the top bowl. After the cloth has been chested on one or other of the two top bowls, it is stripped from the bowl on to a light roller shown clearly with its belt pulley in Fig. 41.
There are two belt pulleys shown on the machine in Fig. 44; one is driven by an open belt, and the other by a crossed belt. Provision is thus made for driving the calender in both directions. The pulleys are driven by two friction clutches, both of which are inoperative when the set-on handle is vertical as in the figure. Either pulley may be rotated, however, by moving the handle to a oblique position.
The compound leverage imparted to the bearings of the top bowl, and the weights of the bowls themselves, result in the necessary pressure, and this pressure may be varied according to the number of small weights used. The heaviest finish on the calender, i.e. the chest-finish on the second top roller, imitates more or less the "mangle finish."
A heavy hydraulic mangle with its accumulator and made by Messrs. Urquhart, Lindsay & Co., Ltd., Dundee, is illustrated in Fig. 45. The cloth is wound or beamed by the mechanism in the front on to what is termed a "mangle pin"; it is reality a thick iron bowl; when the piece is beamed, it is automatically moved between two huge rollers, and hydraulic pressure applied. Four narrow pieces are shown in Fig. 45 on the pin, and between the two rollers. There are other four narrow pieces, already beamed on another pin, in the beaming position, and there is still another pin at the delivery side with a similar number of cloths ready for being stripped. The three pins are arranged thus o°o, and since all three are moved simultaneously, when the mangling operation is finished, each roller or pin is moved through 120°. Thus, the stripped pin will be placed in the beaming position, the beamed pin carried into the mangling position, and the pin with the mangled cloth taken to the stripping position.
While the operation of mangling is proceeding, the rollers move first in one direction and then in the other direction, and this change of direction is accomplished automatically by mechanism situated between the accumulator and the helical-toothed gearing seen at the far end of the mangle. And while this mangling is taking place, the operatives are beaming a fresh set, while the previously mangles pieces are being stripped by the plaiting-down apparatus which deposits the cloth in folds. This operation is also known as "cuttling" or "faking." It will be, understood that a wide mangle, such as that illustrated in Fig. 45. is constructed specially for treating wide fabrics, and narrow fabrics are mangled on it simply because circumstances and change of trade from time to time demand it.
Fig 46 FOLDING, LAPPING OR PLEATING MACHINE
The high structure on the left is the accumulator, the manipulation of this and the number of wide weights which are ingeniously brought into action to act on the plunger determine the pressure which is applied to the fabrics between the bowls or rollers.
Cloths both from the calender and the mangle now pass through a measuring machine, the clock of which records the length passed through. There are usually two hands and two circles of numbers on the clock face; one hand registers the units up to 10 on one circle of numbers, while the slower-moving hand registers 10, 20, 30, up to 100. The measuring roller in these machines is usually one yard in circumference.
If the cloth in process of being finished is for use as the backing or foundation of linoleum, it is invariably wound on to a wooden centre as it emerges from the bowls of the calender, measured as well, and the winding-on mechanism is of a friction drive somewhat similar to that mentioned in connection with the dressing machine. Cloths for this purpose are often made up to 600 yards in length; indeed, special looms, with winding appliances, have been constructed to weave cloths up to 2,000 yards in length. Special dressing machines and loom beams have to be made for the latter kind. When the linoleum backing is finished at the calender, both cloth and centre are forwarded direct to the linoleum works. The empty centres are returned periodically.
Narrow-width cloths are often made up into a roll by means of a simple machine termed a calenderoy, while somewhat similar cloth, and several types of cloths of much wider width, are lapped or folded by special machines such as that illustrated in Fig. 46. The cloth passes over the oblique board, being guided by the discs shown, to the upper part of the carrier where it passes between the two bars. As the carrier is oscillated from side to side (it is the right hand side in the illustration) the cloth is piled neatly in folds on the convex table. The carriers may be adjusted to move through different distances, so that any width or length of fold, between limits, may be made.
Comparatively wide pieces can be folded on the above machine, but some merchants prefer to have wide pieces doubled lengthwise, and this is done by machines of different kinds. In all cases, however, the operation is termed "crisping" in regard to jute fabrics. Thus, Fig. 47, illustrates one type of machine used for this purpose, and made by Messrs. Urquhart, Lindsay & Ca., Ltd., Dundee. The full-width cloth on the right has obviously two prominent stripes--one near each side. The full width cloth passes upwards obliquely a triangular board, and when the cloth reaches the apex it is doubled and passed between two bars also set obliquely on the left. The doubled piece now passes between a pair of positively driven drawing rollers, and is then "faked," "cuttled," or pleated as indicated. The machine thus automatically, doubles the piece, and delivers it as exemplified in folds of half width. In other industries, this operation is termed creasing and, rigging. Some of the later types of crisping or creasing machines double the cloth lengthwise as illustrated in Fig. 47, and, in addition, roll it at the same time instead of delivering it in loose folds.
FIG. 47 CRISPING, CREASING OR RIGGING MACHINE
If the cloth is intended to be cut up into lengths, say for the making of bags of various kinds, and millions of such bags are made annually, it is cut up into the desired lengths, either by hand, semi-mechanically, or wholly mechanically, and then the lengths are sewn at desired places by sewing machines, and in various ways according to requirements.
FIG 48 SEMI-MECHANICAL BAG OR SACK CUTTING MACHINE
Fig. 48 illustrates one of the semi-mechanical machines for this purpose; this particular type being made by Messrs. Urquhart, Lindsay & Co., Ltd., Dundee. About eight or nine different cloths are arranged in frames behind the cutting machine, and the ends of these cloths passed between the horizontal bars at the back of the machine. They are then led between the rollers, under the cutting knife, and on to the table. The length of cloth is measured as it passes between the rollers, and different change pinions are supplied so that practically any length may be cut. Eight or nine lengths are thus passed under the knife frame simultaneously, and when the required length has been delivered, the operative inserts the knife in the slot of the knife frame, and pushes it forward by means of the long handle shown distinctly above the frame and table. He thus cuts eight or nine at a time, after which a further length is drawn forward, and the cycle repeated. Means are provided for registering the number passed through; from 36,000 yards to 40,000 yards can be treated per day.
The bags may be made of different materials, e.g. the first four in Fig. 32. When hessian cloth, II, Fig. 32, is used, the sewing is usually done by quick-running small machines, such as the Yankee or Union; each of these machines is capable of sewing more than 2,000 bags per day. For the heavier types of cloth, such as sacking, S, Fig. 32, the sewing is almost invariably done by the Laing or overhead sewing machine, the general type of which is illustrated in Fig. 49, and made by Mr. D. J. Macdonald, South St. Roque's Works, Dundee. This is an absolutely fast stitch, and approximately 1,000 bags can be sewn in one day.
FIG. 49 OVERHEAD (LAING) SACK SEWING MACHINE
The distinctive marks in bags for identification often take the form of coloured stripes woven in the cloth, and as illustrated at S, Fig. 32. It is obvious that a considerable variety can be made by altering the number of the stripes, their position, and their width, while if different coloured threads appear in the same cloth, the variety is still further increased.
Many firms, however, prefer to have their names, trade marks, and other distinctive features printed on the bags; in these cases, the necessary particulars are printed on the otherwise completed bag by a sack-printing machine of the flat-bed or circular roller type. The latter type, which is most largely used, is illustrated in Fig. 50. It is termed a two-colour machine, and is made by Mr. D. J. Macdonald, Dundee; it will be observed that there are two rollers for the two distinct colours, say red and black. Occasionally three and four-colour machines are used, but the one-colour type is probably the most common.
The ownership of the bags can thus be shown distinctly by one of the many methods of colour printing, and if any firm desires to number their bags consecutively in order to provide a record of their stock, or for any other purpose, the bags may be so numbered by means of a special numbering machine, also made by Mr. D. J. Macdonald.
The last operation, excluding the actual delivery of the goods, is that of packing the pieces or bags in small compass by means of a hydraulic press. The goods are placed on the lower moving table upon a suitable wrapping of some kind of jute cloth; when the requisite quantity has been placed thereon, the top and side wrappers are placed in position, and the pumps started in order to raise the bottom table and to squeeze the content between it and the top fixed table. From 1 1/2 ton to 2 tons per square inch is applied according to the nature of the goods and their destination. While the goods are thus held securely in position between the two plates, the wrappers a sewn together. Then specially prepared hoops or metal bands are placed round the bale, and an ingenious and simple system, involving a buckle and two pins, adopted for fastening the bale. The ends of the hoop or band are bent in a small press, and these bent ends are passed through a rectangular hole in the buckle and the pins inserted in the loops. As soon as the hydraulic pressure is removed, the bale expands slightly, and the buckled hoop grips the bale securely.
Such is in brief the routine followed in the production of the fibre, the transformation of this fibre, first into yarn, and then into cloth, and the use of the latter in performing the function of the world's common carrier.
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