This method serves its purpose very well, but if any alteration is required in the lift of the slackening harness all the levers have to be gone through and altered separately, whereas in the Devoge machine the lift can be regulated to a nicety by moving the fulcrum G and the point O. The slackening harness should be placed from nine inches to a foot behind the ground harness.
The wire M, in [Fig. 145], is for lifting the shaft A, which is required to be lifted every pick. The advantage of using only one needle for the doup and slackening hooks is that it prevents the possibility of the slackener being missed when the doup lifts, as well as being a saving in cards.
By lifting the crossing ends with the ground harness for two or more picks, followed by lifting the same ends in the doup harness for a similar number of picks, an open leno fabric is produced, and a plain figure can be woven by lifting the ground harness plain, or a floated figure can be formed exactly as with an ordinary Jacquard.
FIG. 148.
FIG. 149.
The usual method of putting the design on point paper for these Jacquards is illustrated at [Fig. 148]. In the plan eight ends of leno are shown with four picks in a shed; and eight ends of plain, of which the figure is usually formed, are shown. The design on point paper for this would be as given in [Fig. 149]. Ordinary 8 × 8 paper is used, although there are ten rows of needles. The card-cutter cuts the black squares opposite the ground harness needle, and where the circles come, he cuts so as to lift the doup in the next dent. Thus in the first four cards for [Fig. 149], the card-cutter would cut opposite the third and fourth needles in the ground harness, and opposite the doup needle for the next four ends. The plain would be cut in the ordinary manner opposite the ground harness needles. A larger design for this harness will be found in Chapter X.
Double-lift Jacquards are not yet used beyond the experimental form, as the shaking cannot be done as easily as in a dobby with shafts, but we have heard of the thing being done by knotting the harness above the comber board and lifting the board a little when the cross is being made. Messrs. Eccles, of Preston, some years ago obtained a patent for lifting the standard ends by means of a third knife or griffe. The additional knife was given half the lift of the other two, and its function was to lift the standard ends half way when the doup ends were crossing to the other side. This would, no doubt, enable the cross to be made with ease in a double-lift Jacquard, but the principle is not likely to be a great success.
The doups in leno Jacquards are very liable to wear out unless made of very good material, and some experience is necessary before the harnesses are worked satisfactorily.