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 Precisely the same kind of link is made by the hand wrappers when the warps indicated in Fig. 27 are being withdrawn from the mills.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.
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
By permission of Messrs. Urquhart, Lindsay & Co. Ltd.
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.
