Читать книгу The Jacquard Machine Analyzed and Explained - E. A. Posselt - Страница 13

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Fig. VI. illustrates a needle, as used in connection with the hook. Distance from head to loop, 9–⅛ inches, = a to c. Length of loop, 1–⅝ inches, = c to d. 10–¾ inches entire length.

Fig. VI.

The distance from head to eye (for passing through the hook) is regulated according to the row in which the needle belongs. In the present illustration this is, Head to eye, = 7 inches, = a to b. The eye, = ⅜ inch, = b.

Eight different positions of the distance of the eye from head will be required by an 8-row machine. The needles are made of No. 15–½ bright spring wire. The loop on the end, c to d, permits a pin to be inserted, [see Fig. VII., o], and also holds the needle in position.

Fig. VII.

Fig. VII. gives a clear understanding of the arrangement of hooks, needles, griffe-bars, springs, frame for holding the latter, and the needle-board. This drawing is in accordance with the preceding ones, executed one-fourth of the actual size, and represents the sectional cut of one cross-row in the Jacquard machine containing 8 hooks, (as it is an 8-row deep machine which we explain): e to e´, 1st hook; f to f´, 2d hook; g to g´, 3d hook; h to h´, 4th hook; i to i´, 5th hook; k to k´, 6th hook; l to l´, 7th hook; m to m´, 8th hook. These hooks are held in their required places by the eyes of the needles [see place v at hook 1], through which the former are passed.

The needles rest with their heads in the needle-board, a to b, extending outside, towards the cylinder, for about ½ inch. The rear part of the needle—the loop—is passed between two bars of the spring frame, n, p, and held by the latter firmly, but with sufficient play for a longitudinal motion for pressing towards their springs. The pin, o, is inserted for holding the springs in their places. One pin is required for each vertical row of needles. The part of the spring frame, r, n, p, s, unshaded, is made of cast iron; the shaded part (extension) is constructed of wood. Below the upper crook of the hooks, the black sections represent a sectional cut of the griffe-bars; v to w indicates the rester for the lower hooks, which keeps the latter in their required position.

A study of this illustration will show that when the heads of the needles, a-b, are pushed backwards, in the direction of arrows, the hooks are also moved. If the needles are not pushed, the upper crooks of the hooks will remain in position, as in drawing, over the griffe-bar; and raising the latter will consequently raise every one of these hooks. Therefore, if a blank card is pressed against the 208 needles of the machine, all the needles and hooks will be pushed back, out of the way of contact with the griffe-bars, thus causing an empty lift when they are raised; whereas, by pressing with an empty cylinder, or with a card, containing as many holes as the machine has needles, and so placed that the holes are exactly opposite the needles, none of them would be moved, and each hook would remain vertical over its griffe-bar; and raising the griffe will lift every hook.

As mentioned before, the springs, u, are attached to the needles between the needle-frame, n-p, and the pin, o. Fig. VI., the distance e to f indicates the part of the loop around which the spring is adjusted, and where it rests against the expansion of the loop. f, in Fig. VI., represents the place where pin, o, (as shown in Fig. VII.) passes through the loop and is fastened to the needle-frame on top and bottom. Pressing the needle at the head compresses the spring, as the latter is securely fastened on one end by the wider part of the loop, and on the other end by a pin inserted in the loop and fastened to the frame. Remove the pressure at the head of the needle, and the spring will return to its natural position, pushing the needle into its old place. These springs are made of thin brass wire.

It is necessary to keep the needle-eyes in the proper place, otherwise it would result in bending the hook out of its perpendicular position, and by lowering the griffe its bars would possibly come in contact with the head of the hook, crushing the latter, or doing more damage if not detected at once. Each needle or hook, if worn out, can be replaced by pulling out the pin, o, thus loosening the needle and giving a chance to work the required hook out of the needle-eye.