CHAPTER X

DESIGNS ON PLAIN PURL STITCH MACHINES—AUTOMATIC JACQUARD TYPE—DETAILS OF JACQUARD-DESIGNING ON JACQUARD MACHINE

FIGURES 64, 65 and 66 show some of the design effects which may be made on the links and links system of knitting. Fig. 64 is a basket weave design. To make this we will assume that the machine is set up, that is, has work on it, with the carriage at the left end of the machine. Then all the needles would be in the front plate. The back plate should be racked to its last position to the right. The last working jack in the back plate, left end, should be opposite the last needle in the front plate, but in the right end of the back plate there should be 8 jacks more than needles in the front plate. Now starting at the right, count eight jacks, which leave in operating position; then draw five back out of operating position; leave eleven in operation, and drawn five out. Alternate in this way with eleven in work and five out for the length of the work.

After doing this the position of the jacks would be similar to those shown in the back plate in Fig. 60, except that that illustration showed three in and three out, while we would have eleven in work and five out in the present instance. The three rules marked _m_, shown in Fig. 60, are used for this purpose. They save the time of counting the jacks and drawing them back one or two at a time. By the use of one of these rules, properly cut, all of the jacks to be put out of operation may be moved back in one sweep.

To go back to our design, set the pin shown in the arc _e_, Fig. 60, to stop the racking handle at eight needles, put on six courses or three rounds, stopping with the carriage on the left, which will leave all the needles in the front plate, and rack the back plate to eight needles to the left. Put on three more rounds and rack the eight needles to the right, and continue doing this.

It should be understood that the back plate should never be racked over more than two needles except when all the needles are in the front plate. I have previously explained that when the cams are set for purl stitch, if the jacks are in the operating position in both plates we would make the purl stitch, but in any place where the jacks were drawn back out of operating position in one plate, in that place the needles would at all times stay in the opposite plate and knit the plain jersey stitch.

Now in this basket design we have in the back plate, disregarding the first eight jacks, five jacks that are not operating alternating with eleven that are. Therefore, the first three rounds would make purl stitch on eleven needles alternating with five making plain jersey stitch.

When we rack the plate over eight needles we find that the five slots with the non-working jacks of the back plate are just opposite the middle five needles of the eleven that have been making purl stitch, and are, of course, at the time of racking in the front plate. We also find that the five needles that have been making the jersey stitch in consequence of having been opposite the five non-working jacks in the back plate, are now opposite the middle five of the eleven working jacks of the back plate. Therefore it is plain that these five needles would make purl stitch for the next three rounds, while the middle five needles of the eleven that were making purl stitch would make jersey in the next three rounds. There are always three needles on each side of the five that are racked over that purl stitch all the time.

Two and Two Rib

Fig. 65 shows two designs the lower one being very simple. With the carriage on the left end of the machine arrange the jacks in the back plate two and two, or two in working position and two out. Then move the carriage across to the right end of the machine and we will find that the needles have arranged themselves to conform to the arrangement of the back jacks, alternating two and two in both needle plates. Now move the handle _b_, Fig. 61, to the left and this will raise cams _a_ and _b_, Fig. 62, up into the cam plate out of operation, thus preventing the jacks from moving to their innermost position. Therefore, they cannot exchange needles and so would make a two and two rib fabric, knitting this continuously without any further change.

The upper half of Fig. 65 is made by arranging the jacks in the back needle plate so that five will be in working position, alternating with five out. With this arrangement of the jacks, and without any further manipulation, the machine would knit a straight vertical stripe of five needles purl stitch and five needles plain jersey stitch. If, however, we rack the back needle over one needle every round when the carriage is at the left end of the machine, and all the needles are in the front plate, for five rounds we would have these stripes running diagonally instead of vertically, and the distance they would run to the right or left, depending on which way we racked, would depend on how many times we racked in one direction. In this instance it would be for seven rounds, or rather we would rack over in the one direction every round for six rounds, and on the seventh we would rack the plate back the five needles at once. Then start over racking the other way one needle each round as before to make the second row of diagonal blocks. This racking back of five needles at one time would of course bring the non-working jacks to the position where the working jacks were, and the working jacks to the position where the non-working jacks were. Therefore, the needles that were knitting the purl stitch would begin making plain jersey, while the needles that were making plain jersey would now make purl stitch.

Fig. 66 is simply a two and two rib stitch racked over two needles every four rounds. This racking over two needles with needles in both plates may be done successfully if the stitch is drawn fairly long.

Automatic Jacquard Power Purl Stitch Machine

The automatic links and links or purl stitch machine is what the name would imply; that is, a machine which makes the changes in the stitch and yarn carriers automatically. The word jacquard added to this would convey to the mind of a person familiar with textile processes the fact that the machine automatically makes designs or patterns in the process of knitting.

Fig. 67 shows a Dubied machine of this type which in general appearance resembles their automatic power flat machine. It has the same drum device for counting the rounds, indicated at _d_, with a chain drive somewhat similar to the flat machine, though with this difference: The carriage is connected directly to the chain through a cross head which slides on two rods, instead of through a connection rod. We have the main chain, at _e_, on this machine as on the flat machine, but it is placed on the right end instead of the left. The racking chains which are on the flat machine are not needed on this machine, therefore are dispensed with.

On the ordinary purl stitch machine a large part of the designing is done by a combination of selected jacks in conjunction with the rack; therefore it is desirable to have such a machine built to rack over quite a number of needles. With this machine the designs are made on the jacquard system, therefore this extreme racking is not required and the machine is built to rack but two needles. At _a_ and _b_ in Fig. 67 will be noted two cylinders with grooves cut on a long spiral. They are mounted on a small shaft which acts as a bearing upon which they turn. These operate the jacquard system and should be kept well in mind as they will be referred to later. The letter _c_ indicates the carriage, which is shown, top and bottom, in detail in Figs. 69 and 70.

Fig. 69, it will be noted, is the same in the general layout of the cam system as shown for the hand machines in Fig. 62, in the last article. The upper locks would operate on the front plate and the lower ones on the back one. There are two main points of difference: The cam _x_, which must be used in connection with the cards of the jacquard system and which will be taken up in detail in due course, and the levers _s_ and _t_ which raise the stitch cams that are in the lead and lower the ones that follow and form the stitch at the end of each course. This is done to take all undue strain off the stitch.

It will be noted in the illustration that the left stitch cams are raised and the right ones lowered preparatory to putting on a course by moving the carriage from right to left. At the left end of the machine the position of these cams is reversed for the return course. This is done by a pin set at both ends of the two plates which act on the levers _s_ and _t_. Then we have the extensions of the slides. Numbers 1 and 3 are for changing the length of the stitch. Slides 2 and 5 are for raising and lowering cams _a_ and _b_ to change from purl to plain jersey stitch, or vice versa. The manner of doing this and the action of these cams on the needles and jacks have been explained.

Slide 4 puts the plunger _y_ into and out of operation. This plunger operates the jacquard system by entering the spiral grooves of and turning the cylinders _a_ and _b_, Fig. 67. The four slides marked 6, Figs. 69 and 70, are for changing the yarn carriers, of which there are four. The four small parts indicated by the letter _m_, Fig. 69, are latch openers, which are essential as the machine cannot be operated when the latches are closed. We would be unable to move the carriage across the machine when there was no fabric on the needles to open the latches, without these latch openers.

The small slide indicated at 7 is for changing the position of the cam _x_, swinging on a pivot screw at _z_, which may be moved to any one of three positions. These are the position shown, or horizontal with the lower edge of, and on a line with the lower edge of cams _w_ and _r_, or it may be swung down to a point where the end will be at the lower edge of the cam plate at _v_. The three positions of this cam should be firmly fixed in mind, as they have an important part to play in the jacquard work.

We will now give our attention to Fig. 68, which represents a cross section of the needle plates, showing a pair of jacks and a needle in their respective slots or tricks. Letter _a_ indicates the back plate and _b_ the front one. The back jack _c_ is shown in its outermost position, therefore would be out of operation, while the dotted lines at _h_ show its innermost position ready to receive the needle from the opposite jack. Letters _e_ and _f_ indicate the gibs which cover and hold down the heads of the jacks at all times except when they are at their innermost position; when they are in this position they are under and held down by the bridges or winkles _c_ and _d_, Fig. 69, and are permitted to rise only at the concaves _e_ and _f_ where the exchange of needles takes place. Letter _g_, Fig. 68, indicates the needle, and _i_ is a vertical projection, called teeth, which are between the needles and act as sinkers for the needles to draw the loops over.

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.

I assume that the reader understands that the stops and levers that cause all these automatic changes are controlled by studs attached in their proper places on the chain _e_, Fig. 67, which in turn is controlled by the drum _d_.

We will now take up in more detail the action of the cards and the mechanism provided to actuate them. As stated before, when making a design by this system the card cylinder, together with the cards, is moved up to the edge of the needle plate each round. Referring to Fig. 67, at _a_-1 there is an eccentric attached to the movable cylinder _a_, and there is a connection rod from this eccentric to the small shaft _o_, Fig. 68. Therefore, when the plunger _y_, Fig. 70, enters the spiral groove and moves the length of the cylinder _a_, Fig. 67, the cylinder turns about half way round, which of course turns the eccentric _a_-1, and this moves the card _j_, No. 1, Fig. 68, up to the needle plate. As noted before, any part of this card that has holes in it could not push those, jacks opposite into working position, while that part of the card which remained intact would put the jacks opposed to it in work. Upon the return of the carriage it turns the cylinder _a_, Fig. 67, back to its first position, which movement would of course move the cards away from the needle plate again. The cylinder _b_ is actuated in the same manner as cylinder _a_ as the carriage reaches the right end of the machine, but its function is to turn the card cylinder a quarter turn each time in order to bring a new card into position for the next round and make that part of the design.

How Designing Is Done

Having explained the theory of making designs on the jacquard system we will now show in detail how it is done in actual practice. With the jacquard system there is no limit or end to the designs that may be made, as there is with the other systems used on knitting machines.

Fig. 71 is a photographic reproduction of a design made on this machine. The reader who has studied well and thoroughly digested what has gone before will realize that this design could not be made in any other way, on a machine of this type, without an expenditure of time and labor which would be far beyond the bounds of practicability.

The designer will first sketch out his design on a piece of plain paper, then take a piece of cross section paper and lay it down as illustrated in Fig. 72. This is the layout of the design shown in Fig. 71. Each of the crosswise rows of squares represents one round or two courses, and each of the vertical rows represents a wale or needle. In other words each one of the squares in a crosswise row represents a needle or the loops in one round, and each one of the succeeding squares represents that same needle in the succeeding rounds.

Now to cut the cards we would start with No. 1 and cut them consecutively. Referring to Fig. 72, the blank squares, or the spaces in the cards these represent, should be cut out, and the squares marked with an _x_ would remain intact. Starting at the right side, one needle space is not cut out; then sufficient space to cover three needles or jacks is cut out; then the space of eleven jacks is left intact, then three cut out. This is the full width of the first round of the design, therefore this cutting would be repeated until it covers the desired width of fabric. Card No. 2 would be cut as follows: One space cut, one left intact, three cut out, nine left intact, three cut out, and one left intact. This should be repeated as with No. 1 card. Each card thereafter should be cut according to the marking of the cross section paper, and numbered as cut, so as to avoid trouble in assembling them in their proper order when finished.

It should be understood that the part of this layout from the right side to the dotted line is the complete design, and all to the left as well as above and below, would be a duplicate of this.

After these cards are put on the card cylinder, attached like an endless belt, and the machine is in operation, when card No. 18 has finished the last part of the design, card No. 1 will start immediately in the next round on its part of the design. When it comes to card No. 6, that square will have been completed, and a new square in the center section will have been started.

The two-tone color effect is made by using two different colored yarns and using a plating yarn carrier. This throws one color on the face in the jersey stitch and the other color on the face in the purl stitch.