Jacquard Weaving and Designing

by T. F. Bell

Suppose the design to be as in Figs. 152 and 155, and to be painted for a 200-jacquard, then to allow for double the quantity of warp a 400-jacquard would be required, the machinery being increased instead of the number of cards. Now, to mount a loom for this class of work the simplest plan is to divide the machine and cumber board into two divisions, one half being used for one warp, which may be called the face warp, and the other half for the other warp, which we may call the back warp. A mounting of this description is shown in [Fig. 156], in which the machine is divided into two portions, 1 and 2, with 200 hooks in each; the cumber board is also divided into two sections, marked A and B. Here only four rows of needles are given, but any number can be used. The cords from the hooks 1 to 200 are taken through the back cumber board A, and those from the hooks 201 to 400 through the front cumber board B.

When entering the yarn, one thread is taken from the back warp and drawn into the first mail of the back harness, and the next thread is taken from the face warp and drawn through the first mail of the front mounting. Now, in reference to the card-cutting: instead of cutting two cards one the reverse of the other, one half of the card must be cut the reverse of the other half, the card-cutter cutting the coloured squares of the design (200 checks) on the first half of the card, and going back again and cutting the blank squares on the second half of the card; or, when there is any variation in the twill, the pattern for the face may be painted on 200 checks, and that for the back on 200 checks, and when cut on the card the threads of the warp will be raised in proper order by the mounting.

[Fig. 157] shows this principle of mounting with a straight or Norwich tie, for which it is not so suitable as for the London tie ([Fig. 156]) on account of the crossing over of the harness, though it is not very objectionable if a narrow cumber board be used. Instead of having two separate cumber boards with four or eight rows in each, one broad board with eight or sixteen rows is better for the Norwich tie; then let the first row of the back harness pass down through the back row of the cumber board, and the first row of the front harness pass through the second row of the cumber board, and so on, the back harness filling the odd rows and the front the even rows; and when drawing in the yarn, taking an end from the back and face warps alternately and drawing them regularly over the harness causes them to fall correctly on their respective mountings. Instead of dividing the card in this way and reducing the machine to half its figuring capacity, a double-cylinder machine might be used, the hooks from one set of needles being used for one mounting, and those from the other set of needles for the other mounting; then cutting the face pattern on one set of cards and hanging them on one cylinder, and using a second set of cards containing the back pattern for the other cylinder, should attain the same results, and give double the extent of pattern on the same size of machine, both griffes being raised and sunk together, and both cylinders being also brought in and out together.

Fig. 157

Fig. 158

A modification of cutting the back and face pattern on its own half of the card is to be found in the double-cloth quilting mounting common about Paisley. These quilts are generally of a plain texture, and the figuring is formed by passing one cloth up and down through the other. The machine generally used is an improvement on the old French draw loom, and is shown in [Fig. 158] as it is made, principally of wood, for hand looms. In this sketch the needles and cords in lieu of hooks are not shown, but one row of them is shown in [Fig. 159] with only four hooks to each section instead of eight. H and K are the two lifting levers for raising the griffes or trap-boards A and A¹ (Fig. 159). Nos. 1, 2, 3, and 4, and 1a, 2a, 3a, and 4a are the cords in lieu of hooks to which the harness is connected. A and A¹ are two perforated boards with the slotted holes through which the cords pass, turned in the reverse direction in one from what they are in the other. Each needle is connected to two of these cords—one through each hole-board—and the knots on the cords above the holes stand over the slots or saw-cuts of the holes in the board A and over the round or open portion of the holes in the board A¹, clearly shown at F ([Fig. 159]), so that if the lever H ([Fig. 158]) were pressed down and the board A raised without any card acting upon the needles, all the harness tied to this portion of the machine would be lifted, and if the board A¹ were raised by the lever K, none of the harness tied to this portion of the machine would be lifted. Now, if a blank card were placed on the cylinder, the reverse of this would be the case, and anything between these two extremes can be got by cutting the cards.