III. Straight-Through Tie-up of a Jacquard Loom having Front Harness Attached.

As mentioned in the beginning of this work, every Jacquard machine contains two reserve rows, which may be used for various purposes. One of the purposes to which these rows are frequently put is the enlargement of the design of the fabric by using harness on the front of the comber-board, technically known as “front harness.” For example, in damask table-cloths, we may use the Jacquard harness for producing the border of the fabric. The centre part may be produced with front harness, forming a checkerboard, or some similar effect. This process may be reversed by designing the centre of the table-cloth for the Jacquard harness, and the border for the front harness.

Fig. XXXII.

A third method is to design part of the centre and part of the border for the Jacquard harness, the other parts being designed for the front harness. This tie-up is also used to a great extent in the manufacture of dressgoods, etc., where stripe effects produced by the front harness, alternate with floral or geometrical designs produced by the Jacquard harness.

In [Fig. XXXIII.] the centre of a table-cloth cover is shown to further illustrate this method of tying-up. One-half of the width of the design is for the Jacquard harness; the other half is for the front harness. To produce the required checkerboard effect these front harness are used here in two distinct sets.

The 1st set = 5 harness, working on the 5-leaf satin warp for face, alternating with the

2d set = 5 harness, working on the 5-leaf satin filling for face.

If only 8 front harness should be used for the design, we should have the

Set 1 to alternate with set 2 to form the check. Care must be taken that the number of checks formed by the front harness are evenly arranged to the figured part of the fabric. For example, [Fig. XXXIII.], in the front harness part of the design shows 5 warp checks and 5 filling checks in one row, = 10 checks.

Fig. XXXIII.

Suppose 10 front harness are used and 20 warp-threads allowed for each check; then 20 × 10 = 200 warp-threads, all used for effects by the front harness.

This requires 200 warp-threads for figure effects to be used by the Jacquard harness.

The repeat of the pattern is therefore 400 warp-threads, which is produced by straight-through tie-up, front harness attached, with 200 hooks and needles for FIGURE PART of the design, plus 10 hooks and needles for CHECKERBOARD PART of the fabric taken from the 16 hooks and needles of 2 reserve rows, leaves 6 hooks and needles for selvedge, etc.

As previously stated, the front harness may be used for dressgoods fabrics. In this way the design may be enlarged to any required extent.

[Fig. XXXII.] illustrates this method, using an 8-row Jacquard machine, with 4 front harness adjusted, in common use for the manufacture of dressgoods fabrics, damasks, etc.

Fig. XXXIV.

[Fig. XXXIV.] shows a fabric designed for dressgoods forming an all-over-set pattern. In this design parts F and F´´ must be executed with the Jacquard leashes; parts G and G can be executed with front harness. For example: parts F and F´´ require each 100 hooks, the ground part to be woven in 4 harness broken twill. We find the answer as to number of warp-threads in the repeat and number of hooks required for weaving as follows:

F= 100 threads.
G = 100 threads (because covering the same distance as F in part of the fabric.)
F´´= 100 threads
G= 100 threads
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400 warp threads in repeat.
F= 100 hooks.
F´´= 100 hooks
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200 hooks for figure.
4 hooks for weaving the ground, front harness.
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204 hooks required to weave design, [Fig. XXXIV.],repeating with 400 warp-threads.