Flat Machine Knitting and Fabrics

by H. D. Buck

The Jacquard Mechanism

The jacquard system of designing is simply a method of providing means to select and put into operation any desired needle or needles at any predetermined place in the fabric. The mechanism to do this is shown in Fig. 68. The letter l indicates a four cornered star shaped bar called the card cylinder, which is the length of the needle plate. The letter j indicates what are called cards and are also the same length as the needle plate and as wide as one side of the card cylinder. These are made from either thin sheets of steel or from stiff strong paper board, and are attached to one another by rings or other means so as to form a continuous band around the card cylinder. The illustration shows ten of these cards, but the number used depends on the design being made, for there is one card for each round in the design.

To return to the card cylinder l, this is mounted on a shaft which is supported by two uprights or arms, one at each end, shown by the broken lines at n, which in turn are attached securely to the rocker shaft m. This arrangement permits the card cylinder to be swung forward to the needle plate and back to the position shown at any predetermined time or place. As noted before, the back jack c is out of working position, therefore as long as it stays in this position the needle would operate in the front plate only and make a plain jersey fabric.

If, when the carriage is at the left end of the machine, we should swing the card cylinder with the blank card j, No. 1 (which is a card without any openings in it) up to the needle plate, it would push these back jacks up into working position and on the next course the needles would cross over into the back plate and make the purl stitch. Now bear in mind that the basic principle of designing of this character is in making the design of one stitch and the ground of the other. It is quite obvious that if we provide means to sweep all the back jacks to their outermost positions and out of operation every time the carriage is moved from the right to the left end of the machine after having passed the needles across to the front plate, then swing a card with holes cut through at certain intervals up to the needle plate, those jacks that come into contact with that part of the card that is intact would be pushed into working position, while those that were in front of the openings or holes would pass through and not be affected. Therefore, on the next round the needles opposite these would make the jersey stitch, while all the others would make purl stitch. On the last course of the round from right to left the jacks would be swept back out of operation, the card cylinder l would be turned a quarter turn, bringing another card opposite the needle plate, and another and perhaps different lot of jacks selected for the next round.

The card cylinder is turned the quarter turn when the carriage is approaching the right end of the machine by the plunger y, Fig. 70, engaging the spiral in the cylinder b, Fig. 67, and the cards are moved up to the needle plate when the carriage approaches the left end of the machine by this same plunger engaging the spiral in cylinder a.

At k in Fig. 68, is shown the face of a portion of a card as it might be cut. Beginning at the opening at the left, the heels of three jacks would pass through this. The space next to the right, being intact, would push six jacks into operation; and so on throughout the length of the fragment of the card shown as indicated by the figures. This drawing was made to represent a card to be used on a needle plate cut eight needles to one inch, and while the scale is cut down somewhat in the reproduction the proportions would remain the same.

Now as to the means provided to make the changes shown as necessary we will refer again to Fig. 69, and to the cam marked x. As stated before, this cam may be swung on the pivot screw z, automatically, to any one of three positions. When it is in alignment with cams w and r it has no effect, as when the jacks are in their normal knitting position the butts will pass just above and when they are out of working position they will pass just under these three cams. Now it will be noted that cam x is placed at the extreme right end of this lock or set of cams, in consequence of which it must always be put into operation when the carriage is at the right end of the machine, and it performs its functions as the carriage is moved to the left and after the stitch formation of this course is completed.

The cam is moved into the desired position by the slide 7, which comes in contact with movable stops at either end of the machine. When the jacquard system is in operation this cam would be moved to the position shown in the illustration while the carriage was on the right, consequently as the carriage is moved to the left end of the machine the needles in the back plate would be passed to the front plate and immediately after this the back jacks would be swept out of the operating position by this cam.

When the carriage reached the left end of the machine this cam would be moved down in alignment with cams w and r, so would be in the position that would not make any change in the position of the jacks.

In making some kinds of work it is desirable to put all the back jacks in and out of operation at certain times. We have just explained about putting them out of operation. To put all of them in the working position without using the jacquard the before mentioned movable stop comes in contact with another slide just under slide 7, when the carriage is moved to the right end of the machine, and this slide will swing the point of cam x to its lowest position at v, and in this position, as the carriage is moved to the left, it will sweep all the back jacks into working position ready for the next course. As the carriage finishes its travel to the left, the stop at that end would of course move this cam to its neutral point.