The Jute Industry: From Seed to Finished Cloth Part 5

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 quant.i.ty 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.

CHAPTER XII. WINDING: ROLLS AND COPS

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 const.i.tute 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 f.l.a.n.g.ed 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 ill.u.s.trates one of the modern bobbin winding machines for jute made by Messrs. Charles Parker, Sons & Co., Dundee. The finished product is ill.u.s.trated 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 ill.u.s.tration.

The distance between the f.l.a.n.g.es 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 ill.u.s.tration, 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 pa.s.ses 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 f.l.a.n.g.es are required, and hence the initial cost as well as the upkeep of the foundations for rolls is much below that for bobbins.

[Ill.u.s.tration: _By permission of Messrs. Charles Parker, Sons & Co_.

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 s.p.a.ce required for the spinning bobbins. When, however, rolls are wound from hank, as is ill.u.s.trated 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 ill.u.s.trated 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.

[Ill.u.s.tration: FIG. 23 ROLL WINDER FOR LARGE ROLLS _By permission of Messrs. Douglas Fraser & Sons, Ltd_.]

The machine ill.u.s.trated 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.

[Ill.u.s.tration: FIG. 24 ROLL WINDING MACHINE (FROM HANKS) _By permission of Messrs. Charles Parker, Sons & Co_.]

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 ill.u.s.trated 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 ill.u.s.tration 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.

[Ill.u.s.tration: _By permission of Messrs. Douglas Fraser & Sons, Ltd_.

FIG. 25 COP WINDING MACHINE]

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.

[Ill.u.s.tration: FIG 26 COP WINDING MACHINE _By permission of Messrs.

Urquhart, Lindsay & Co., Ltd_.]

CHAPTER XIII. WARPING, BEAMING AND DRESSING

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 ill.u.s.trated 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 ill.u.s.tration. 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 ill.u.s.trated 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 circ.u.mference of the mill represents the length of the warp.

[Ill.u.s.tration: FIG. 27 A ROW OF MODERN WARPING MILLS]

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 pa.s.sed 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 ill.u.s.trated 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.

[Ill.u.s.tration: FIG. 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.