Straight-Through and Point Tie-ups Combined
E.—Mixed Tie-up.
Containing in one repeat of the design the straight-through tie-up and the point tie-up, one full division, for the centre; the point tie-up, in half divisions, repeating once through on each side of the fabric, to make the border. These arrangements of tie-ups are used to a great extent in the manufacture of damask fabrics of every denomination.
The principle of using mixed tie-ups, Fig. LII., is found in the necessity of producing large designs, containing varied effects, with a proportionally smaller Jacquard machine. Under whatever management the straight-through and the point tie-ups are combined, their principle remains undisturbed. Every time we arrange a Jacquard loom on a mixed tie-up, we must consider that any subsequent design must be arranged with reference to the same principle as the one in use, otherwise the work must all be rearranged, which would have to be done even for the smallest change in the number of ends for each effect.
Take for illustration a damask fabric, Fig. LIII., handkerchief, bureau scarf, art square, etc. The details given will make the work quite plain:
Part of comber-board from A to B, or D to C, illustrates one-half of the board and procedure of tying-up. The design below also shows only one-half of the fabric. Arrow, G, near comber-board, and arrow, M, near fabric, are placed to indicate the direction in which a repeat is obtained. The fabric will form its centre at D, repeating towards each border and selvedge. This is illustrated in the comber-board by the 1-row deep, outside of line A, D. Harness-cords indicated by dotted lines. The threading of this last mentioned row, as well as the threading of the half division of the point tie-up, is indicated by arrows H and K, forming the centre by means of harness-cords 193 and 193. The straight-through tie-up part of the fabric is found between E and F, containing 12 repeats in the centre, and also the same number in the lower border. In the comber-board is illustrated this arrangement, repeating the first row, containing harness-cords 1, 2, 3, 4, 5, 6, 7, 8, twelve times, and the last hole of the third row containing harness-cord No. 24, twelve times. On the bottom of the comber-board these 12 repeats are indicated by 12 small arrows between parts E to F.
The first row in the first division of the straight-through tie-up is completely threaded; the other eleven have only the harness-cord from leash 1, as indicated; this is done so as not to confuse the eye with too many lines. The border of the fabric is arranged for harness-cords 25 to 192 on the point tie-up, having one-half division on each side. Arrow L indicates the right-hand border. The border on the left requires the same harness-cords which are threaded in comber-board from right to left; hence the borders of the fabric contain the same design repeating from the centre towards the selvedge.
At the beginning we stated that the use of mixed tie-ups made it possible to employ a smaller size Jacquard machine for large designs containing various effects. The following analysis of Fig. LII. shows very clearly how this is done.
Number of warp-ends in one complete repeat in width of the fabric:
Border, right-hand, = 168 threads.
Centre, straight-tie, = 288 threads.
Centre, point-tie, { = 168 threads.
{ = 168 threads.
Centre, straight-tie, = 288 threads.
Border, left-hand, = 168 threads.
——
1248 ends warp in fabric.
Number of needles required to produce the design:
Border, = 168 needles.
Centre on straight-tie, = 24 needles.
Centre on point-tie, = 168 needles.
360 needles required for producing the complete design, thus saving the difference between 1248 and 360, or 888 needles; all of which is accomplished through the use of the mixed tie-up.
Number of harness-cords required for each leash:
Leashes 1 to 24 contain 24 cords for one repeat of the entire design. Leashes 25 to 360 contain 2 cords for one repeat of the entire design. It is not always practicable to reduce the effects in a design to the lowest possible number of needles. On account of the changes in styles, it is best to arrange these tie-ups with a view to giving as much opportunity as possible to the designer. In the present tie-up experience teaches that it will be more advantageous to arrange the straight-through tie-up either for 6 divisions to 48 ends each, or 4 divisions to 72 ends each. 360 needles, as figured at the beginning, require a 400 machine, or, counting reserve rows, 416 needles; hence we can, without disadvantage, increase 360 needles to 384 or 408, which will give a greater scope, if required, to make a new design.