Jacquard Weaving and Designing

by T. F. Bell

Fig. 136

A is the doup or dead leash, B the doup standard, or what answers to the doup standard in heald work. C and D are the leashes carrying the plain or lying threads, and E the leash carrying the crossing thread, the crossing in this case being one thread round two. F is the doup. [Fig. 136] shows the harness drawn for the open shed, and it will be observed that the dead leash A is connected with the back harness E, so that when this leash is raised to form the shed it draws up the dead leash, also relieving the doup. There was one trouble with these dead leashes—namely, that they were liable to twist round the standards when close to them in the cumber board, sometimes being put through the same hole or the next one; but by having them in front and a little distance off this could be avoided. Wires or cords were sometimes stretched across between the lingoes to prevent the twisting. [Fig. 135] shows the harness drawn for the cross shed, the doup standard being drawn up, drawing the doup up with it. The doup was fastened into the mails as shown at No. 1, [Fig. 135]; but a better plan is to have double-eyed mails, and fasten the doup as at No. 2. This form of harness is now superseded by one having all the doups on a shaft in front of the harness, which consists of two parts—namely, the back harness and the douping harness (which is about 3/4 in. to 1-1/2 in. in front of the former); the doups are connected with this latter harness, and all the doups may be on one shaft, whether for one, two, or more rows of standards in the front harness. The doups on the shaft are known as a ‘slip heald’ or ‘slip.’ This is a much simpler and more convenient method of working than the preceding.

[Fig. 137] shows a simple and effective gauze mounting for a 4⁰⁰ jacquard, the cords being carried up to the machine in the usual way. A is the breast beam of the loom, B the reed, C the back rail, and N the yarn beam. D is the slip heald, or doup, which is simply a half-leaf of ordinary clasped heddles, made of cotton or worsted, fine or coarse, as may be desired for the quality of work to be wrought. E is the front or doup mounting, connected with the two front rows of the machine, and passing through a small cumber board in front of that for the body of the harness; it is bolted so that it can be shifted to regulate the distance between the doup harness and that of the figuring. The distance between the two harnesses may range from 3/4 in. to 1-1/2 in., or whatever is found most suitable to ease the strain on the yarn and make a clear shed. G is the cumber board, and F the body of the harness for working the figure.

Fig. 137

The method of slackening the threads that are drawn into the doups is perhaps the principal feature of this mounting. When one or more slackening bars are used it is plain that all the threads that pass over the bar that is oscillated will be slackened at once, though for figured work it may be that only a very few of these threads should be slackened, and if the remainder or any portion of them are raised by the back leashes they should be kept tight at the back so as to enable them to draw up the slack doups. It follows, therefore, that for giving good work and keeping the threads at a regular tension, every thread in the doups should have its own independent slackener. It is not absolutely necessary that this should be so; strong twist cotton or worsted yarn will work very well in a harness with one slackening bar vibrating for each shot, though it must throw an irregular strain on the yarn, and it requires to be tightly paced.

In [Fig. 137] the slackening arrangement consists of a small back harness, as shown at I, through which all the whip threads are drawn; these threads then pass over one lease rod and under the next one, as shown, and then on to the harness to be drawn in according to the draught of the gauze. The harness consists of small mails attached to lingoes with twines in the same way as the lower portion of the ordinary harness is prepared, but the mails are rounded off above the eye or centre hole without having the top hole for threading the upper portion of the harness to. The cumber board of this harness must be nicely set, so that the lingoes will hang on the yarn without drawing the mails quite close on the cumber board, which soon would cut the twines. To regulate this the cumber board and back rail must be set in relation to each other and the mails of the harness so as to produce the desired effect. A medium position for working may be taken as follows:—Cumber board 12 in. behind harness and 6 in. in front of back rail. Back rail 2 in. above the level of the mails in the main harness, and cumber board of small back harness 3 in. below the level of the mails, or 5 in. lower than the top of the back rail. The back lease rod might then come in about 8 in. behind the harness. The weight of the lingoes on the back harness must be regulated to suit the strength of warp to be wrought; about 30 to 40 per lb. for, say, from 40/2 to 80/2 cotton would suit. The mails for the body of the harness may be 25’s or 30’s, or the same as for ordinary work, and those for the doup standards heavier, say 18’s or 20’s. In addition to this harness for slackening, or rather for keeping a yielding tension on the whip, there is a slackening bar supported by a lever K L M at both sides of the loom. This lever has its fulcrum at L, and is attached to the swords of the lay at M, and therefore vibrates at every beat up. The slackener acts as a positive motion, and keeps the threads from tightening up or being drawn forward by the twisting; it acts on the body of the threads, and the harness acts on them individually.

This, when properly set, is an easy motion, and produces a good firm gauze. It is a Bradford patent. Now, in reference to the working of the gauze: The harness is levelled much in the same way as for ordinary work, the mails being 1-1/2 in. or 1-3/4 in. below the level of the breast beam. The doup mails should be a little lower than those for the harness, say 3/16 in. or 1/4 in.