XIII.—Tying-up Jacquard Looms for Gauze Fabrics.

Gauze fabrics are produced by a separate system of weaves, which have the peculiar characteristic of warp-threads not lying parallel to each other. One kind of this warp is called the “douping warp” or “whip-threads;” these are twisted around the ground-warp. The ground-threads, as well as the whip-threads, which work together, must be drawn into one dent.

Jacquard gauze can be worked in various ways; for example: One whip-thread against one or more ground-threads. More than one whip-thread against one or more ground-threads.

There are two methods of tying-up for gauze fabrics: 1st. A tie-up in which the doups are worked by one, two, three or four shafts in front of the Jacquard harness. 2d. A tie-up in which the gauze figuring is done all over the fabric, requiring each doup to be arranged for working separately. If the ground-threads and whip-threads are worked from the same Jacquard machine, the latter must be divided into two sections: 1st section for the ground-threads with ground heddles; 2d section for the whip-threads with standard heddles.

If a fabric contains the gauze in the form of a stripe, arranged one end ground and one end whip, the same number of hooks are required for the ground and whip-threads of each section, and an extra dead harness must be employed; but if this arrangement of one end ground and one end whip must form figures, then the ground and whip-threads must form the first section, and the whip-threads alone the second section. In this case the second section requires only half as many hooks as the first; and for the same reason, if we are forming figures with two ground-threads and one whip-thread, the first section will contain three times as many hooks as the second, etc. Very often two whip-threads are used for twisting, in which case they must be drawn together in the doup. If several whip and ground-threads are drawn into one reed they usually work independently at first on a regular weave; following this is the gauze weave formed by a certain number of whip-threads raised either on the left or right of the ground-threads contained in the same dent. This movement brings into operation the second section of the machine containing the harness-cords for the standard heddles. The technical terms for these various combinations are: single-thread gauze, double-thread gauze, triple-thread gauze, etc.

The tie-up most generally used requires two-thirds of the needles for ground heddles and one-third of the needles for standard heddles; hence, if using a 200 machine we find: 128 needles and hooks for the ground heddles, and 64 needles and hooks for the standard heddles. [See [Fig. LXXXVII.], p. 65.]

Fig. LXXXVII.

The comber-board is divided into two sections. The rear part (2/3) is used for the ground, the front part (1/3) is used for the standard.

Threading of the Harness.

Thread the warp into the ground heddles in the same manner as a common straight-through tie-up. Then take the first left-hand thread of the warp and draw it through the doup. The next two warp-threads draw above the first one on the left-hand side of the same doup. These three warp-threads must be drawn together in one dent. After drawing the first pair in one dent, leave one, two, or more dents empty, according to the fabric. The 4th, 5th and 6th warp-threads, also each subsequent pair, are threaded the same as the first.

Fig. LXXXVIII.

Fig. LXXXIX.

Fig. XC.

Figs. [LXXXVIII.] and [LXXXIX.] are designed for illustrating this point. The lingoes for the doups are about one-half the weight of those used for the ground heddles.

[Fig. XC.] represents a fancy gauze to be executed in this manner.

Fig. XCI.

Fig. XCII.

Fig. XCIII.

Fig. XCIV.

Fig. XCV.

[Fig. XCI.] represents the threading of the harness for a gauze fabric: f, g, first and second warp-thread, over the doup; h, i, third and fourth, through the doup.

Figs.[ XCII.] and [XCIII.] illustrate the two movements of the harness in the gauze weave.

Figs. [XCIV.] and [XCV.] illustrate the movements of the harness in the regular weave: a, b, represents the comber-board; c, the place where the doup is fastened to the dead harness; d, e, the standard heddle; f, g, h, i, the mails of the common heddles.

The following are the fourteen different movements that might be required in regular weaving. The figures show the number of threads up and the number down, thus:

equal first warp-thread up; second, third, and fourth down.

1. = f up.
2. = g up.
3. = h up, doup raised.
4. = i up, doup raised.
5. = f and g up.
6. = g and h up, doup raised.
7. = h and i up, doup raised. [Illustrated by Fig. [XCIII].]
8. = f and h up, doup raised. [See Fig. [XCV].]
9. = f and i up, doup raised.
10. = g and i up, doup raised. [See [Fig. XCIV].]
11. = f, g, and h up, doup raised.
12. = g, h, and i up, doup raised.
13. = f, g, and i up, doup raised.
14. = f, h, and i up, doup raised.

These fourteen different movements cover all the possible changes in regular weaving. The movement (7) illustrated in [Fig. 8], in addition to forming the regular weave, is also necessary to the formation of the gauze weave.

These few explanations clearly show the great variety of effects possible for the designer; for he can figure with the regular method of weaving, and can also figure gauze weaving to exchange with regular weaving, forming a separate design on the fabric.

Modifications of the Single Lift Jacquard Machine.

Having thoroughly described the construction and action of the regular Jacquard machine, it now remains to illustrate and explain its modifications. Among the most prominent are: