Fig. 114
An ingenious method of working the heddles of a pressure harness by the jacquard was invented in Bethnal Green shortly after the introduction of the original machine. It was used for weaving the richest silk damask, which had 400 threads of warp per inch and about one-fifth that number of weft shots, so that five threads of warp might be drawn into each mail without making the pattern appear any coarser in the warp than in the weft. A sketch of this mounting is given in Fig 115. A shows the hooks for working the heddles, and B those for working the harness. Eight hooks are given for working four leaves of heddles. It will be seen that a cord from two hooks passes round one of the pulleys C, and each of the heddle shafts is attached to one of these pulleys. These hooks may be raised by the griffe of the jacquard, which would require to rise and fall for every shot, or the griffe may be held up for the number of shots to the card, and the hooks for working the shafts may be wrought by a small dobby. When one of each pair of the hooks A is raised, the heddle shaft connected with it is raised to the middle position, as shown by the pulleys 1 and 2, and the leaves connected with them. If neither of the hooks is raised for any shaft, it will remain sunk, as shown in No. 3; and if both the hooks are raised, the leaf will be raised to its top position, as No. 4. The leaves are drawn down by weights or springs.
Fig. 115
TWILLING JACQUARDS
