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Cotton Weaving and Designing / 6th Edition cover

Cotton Weaving and Designing / 6th Edition

Chapter 25: THE SPLIT HARNESS.
By John T. Taylor
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About This Book

A practical manual that systematically explains the stages and machinery used in preparing cotton yarn and producing woven cloth, beginning with winding, warping, sizing, beaming, and looming. It surveys hand and power looms, drop and circular box looms, dobbies, jacquard and leno weaves, and specialized techniques such as terry looms, card cutting, and lappets. A chapter on automatic weft-replenishing devices describes emerging mechanization. The book also presents the principles and methods of textile design and figured patterning, and supplies calculations, worked examples, and numerous diagrams to guide students and practitioners in planning, setting up, and troubleshooting weaving operations.

THE SPLIT HARNESS.

The split harness is an ingenious method of increasing the size of pattern which can be woven on a given Jacquard. What is termed a “double-scale” split harness consists of two adjacent lingoes being connected to each hook in the machine. Thus with a 400s machine there are 800 mails in a pattern. A few lingoes are shown at Fig. 124 tied up in the manner of a double-scale harness. The connections to four hooks are shown. Underneath the comber-board a loop is made in the harness thread, and shafts SS, either wood or metal, are inserted through the loops in each row in the harness. These shafts are worked by the spare hooks in the machine, and in the places where the ends are left down by the Jacquard, the shafts, being lifted to a given ground pattern, will weave the ends singly. In Fig. 124 the shafts are shown lifted to weave a plain or tabby ground, every alternate one being lifted. Hooks No. 1 and No. 2 are lifted by the Jacquard, and hooks 3 and 4 are left down, and it will be seen that where the hooks are down, half the ends will be lifted by the shafts. The ends, when lifted by the Jacquard, cannot be woven separately with this harness, and therefore the bindings in the figure will show in twos, which, unless the harness is a fine one, has a tendency to make the cloth appear coarse. Satin or twill grounds may be woven. In fact, the ends left down by the Jacquard may be woven singly to any pattern which repeats on the number of shafts used, or into the number of rows which the harness is deep in the comber-board. Of course either the figure or the ground may be woven singly, according to the way the pattern is designed, but not both.

FIG. 124.

In silk weaving, harnesses are built on this principle to a threefold scale—that is, with three mails attached to each hook—and as in the double-scale a figure repeating on 800 ends can be woven on a 400s machine, so with a threefold scale a 1200 figure can be woven on a 400s machine. In this case the bindings in the figure will be in threes, but the ground ends may be woven quite singly by the shafts.

This principle is only adapted for very fine reeds in cotton goods, but is often used in silk manufacture, where 300 or 400 threads per inch are not uncommon.