Flat Machine Knitting and Fabrics

So far as the knitting mechanism is concerned, the flat jacquard machine is designed and constructed along the same lines as the ordinary flat machine, with the card cylinder for cards and the other necessary appurtenances added. Fig. 83 is a general view of a Dubied jacquard machine, which is semi-automatic but operated by hand. This illustration and the other photographs for this chapter were secured through the courtesy of D. Nusbaum & Co.

The card cylinder and cards are practically the same as used on the purl stitch machine and explained in a former chapter, but obviously the application must be somewhat different owing to the different construction and manner of operating the needles in this machine. Inasmuch as there are two sets of needles opposed one to the other, and each set forms the stitches which show on their respective sides of the fabric, it is possible and customary to make the designs in solid colors, differing in this respect from the links and links or purl stitch machine.

The jacquard designed fabrics are usually made in what would, on an ordinary machine, be the one and one rib or plain stitch. The tuck or cardigan stitch is not resorted to to bring out the design as in some other systems. Strictly speaking, however, the stitch is not what could properly be called a rib stitch, but is a combination of a plain rib and jersey stitch when made on the single jacquard, and is almost wholly of the jersey stitch construction when made on the double jacquard where the design is brought out on both sides of the fabric. The single jacquard is so called when the jacquard arrangement is on one plate only, usually the back one. The double jacquard machine is one which has the jacquard attachment on both the front and back plates. With the single jacquard the design can be brought out on one side of the fabric only, while with the double jacquard the design may be brought out on both sides of the fabric, but the colors would be reversed.

Before going into the mechanical construction of the attachment we will to some extent analyze the fabric to find out what must be done to produce it. Referring to Fig. 87, which is a photographic reproduction of a fabric made on the machine under discussion, it will be noted that both the design and the ground are in solid colors. The rectangular figures which might be called the design are in solid black, while the squares, both the large ones and the small ones, which would be the ground, are solid white. It should be understood that there are two yarn carriers used in making this fabric, one for the white yarn and one for the black, and that these carriers are changed every round; that is, one round of white, and one round of black, alternating throughout the fabric.

Now inasmuch as we know that the fabric is made in the plain stitch, it is quite obvious that in order to make this design means must be provided to permit only those needles to knit which are making the white ground on any course in which the carrier with the white yarn is being used. Similarly only those needles making the black design must be permitted to knit on the course in which the carrier with the black yarn is used. The needles or wales, of course, run vertically in the fabric, while the rectangular design is diagonal, therefore it is plain that the number of needles or their relative positions must be changed each course.

In this fabric the design is brought out on one side only, the back plate, and the needles on the opposite side or front plate are knitting each time the carriage is moved across the machine as explained in detail later. This may be plainly seen in Fig. 87, where the corner is turned over to show the back of the fabric.

Now to find the method of selecting the proper needles at the proper time we will refer first to Fig. 86, which is a photographic reproduction of the cam system used in this machine; also to Fig. 90, which is a drawing of a cross section of the needle plates. It will be noted in Fig. 90 that there are two separate needle plates. The top one is for the needles proper, while the lower one is for the auxiliary needles.

These two plates are in perfect alignment, both as to the surface and the needle tricks or slots. In the double jacquard the front plate would be in two parts and a duplicate of the back plate, but in the single jacquard the front side would have what is the upper plate on the back side only, and would use the short needles as shown at b, Fig. 89.

The Cam System

Referring now to the cam system shown in Fig. 86, it will be noted that while in general appearance the upper and lower set of locks are similar, the wing or stitch cam l and m are not only different in shape from the lower wing cams f and g, but they are set differently in their relation to the V or rise cams a and c.

The cams as shown are set in the proper position to make jacquard or design work. The upper rise cams c, d and e are drawn up into the plate out of working position, therefore those needles selected to operate on any course must be raised by the lower rise cams a and b. The upper lock operates on the butts of the needles proper shown at b, Fig. 90, while the lower lock operates upon the auxiliary needles shown at a in the same illustration. Now, then it is plain that the needles proper will not be raised up, therefore cannot draw new loops or knit unless they are raised by the auxiliary needles a, Fig. 90, which in their turn are raised by the cams a and b, Fig. 86. But it should be noted that the auxiliary needles are drawn down below the point of the rise cams a on each course, as the wing cams f and g extend below these corners, therefore, on every course, unless one of the wing cams f or g is drawn up into the cam plate out of working position, all of the auxiliary needles are drawn down out of working position and will not operate on the next succeeding course unless put into working position by other means.

These wing cams f and g are chamfered off on the outside, so that any auxiliary needles pushed up above the lower end and into operating position will slide under and raise them up into the cam plate. The inner edge is a square corner consequently will, upon coming in contact with the needle butts, draw them down out of the working position. The auxiliary needles being a separate unit have no effect on the needles proper on their downward movement, but must, of course, raise them on the upward movement by coming in contact with the lower ends.

Those of the needles proper that are moved up into work are brought down again and form new loops by the stitch cams l and m, Fig. 86. The small triangular cams j and k are for clearing the needles when a very short stitch is being drawn by the stitch cams l and m.

Now to show how the needles are selected we will first refer to Fig. 89, which shows the needle proper at b and the auxiliary needle at a. The auxiliary needle has a joint in it as shown at h to permit the lower end e to swing to the position shown by the dotted line i.

Fig. 90 shows the auxiliary needles in position with the card cylinder and cards in place ready to push them up into operation. Those needles which it is desired not to operate at all, such as the needles at the end of the plate that may not be needed, are drawn down and the ends are turned down to the point where they are at right angles to the plate, as shown by the dotted line at i. When they are in this position the cards cannot of course push them up into operating position. The short nib that looks like a part of a needle, indicated at f, and the card cylinder shown at g are not a part of the mechanism under consideration, but are another method of needle selection which will be explained later.

Fig. 84 is a general view of the back of the machine showing a set of cards on the card cylinder ready for work. Fig. 85 shows the mechanism used to bring the cylinder with the cards into action. The cards and cylinder need no distinguishing mark as they should be easily recognized from what has gone before. The same thing applies to the auxiliary needles just above, part of which are turned down to the point where they cannot be put into operation.

Letter j indicates the end of the shaft upon which the card cylinder is mounted, and c is the elongated opening in which it moves up and down. This opening is on the same diagonal plane as the needle plates and has its duplicate at the other end which carries the other end of the card cylinder. The rocker shaft d is mounted just under the card cylinder and has two levers securely attached, the other ends of which are connected to the card cylinder shaft, one at either end. On the outer end of the rocker shaft d is another lever indicated by the letter e. This is connected to the camway h through the extension k. This camway is mounted in such a manner that it can be moved only in one direction, and that direction is up and down diagonally or on the same plane as the back needle plates.

As the carriage reaches the extreme end of its travel the pin g, which is attached to the carriage, enters and follows the camway. Inasmuch as the cams are set on an incline this pin or plunger must raise the camway together with the end of the lever e. Through the rocker shaft d and the two levers before mentioned as connecting the rocker shaft with the card cylinder, this will bring the card cylinder up to the lower edge of the auxiliary needle plate. This action will of course push all those needles into action that come in contact with the particular card that may be on that side of the card cylinder at the time. Where the openings are cut in this card the needles will pass through and have no contact, therefore will not be pushed up into working position.

As the card cylinder returns to its lowest position it is turned a quarter turn by the stationary hooked dog a, which catches a tooth, of which there are four, of a ratchet wheel which is also securely attached to the card cylinder shaft. In this way the card cylinder is turned a quarter turn each time it is moved up to the auxiliary plate, which brings a new card into position to make another selection of needles for the next course.

Letter f indicates a counterweight which, as will be noted, is attached to the rocker shaft d to assist in returning the card cylinder to its lowest position and hold it there after its return. Letter i indicates an ordinary pattern chain on which the proper studs are attached to change the yarn carriers automatically.

Three Units May Be Racked

In this type of jacquard machine there are three separate and distinct units which may be racked or moved at right angles to the movement of the needles. They are, first, the needle plate proper which racks the same as the ordinary flat machine; second, the auxiliary needle plate; and third, the card cylinder together with the cards. The racking of the needle plate proper is necessary to make those designs in which a rack in the fabric is required, but the other two are chiefly a matter of convenience to save making up cards. There are many designs that may be made with one or four cards, or even without any cards, by manipulation of these racking movements, where otherwise quite a string of cards would be required.

We will take for example any design consisting of a small block or check within the limits of the needles the auxiliary plate will rack over. Such a design may be made without cards in this way. Say we wish to make a black and white check four needles wide and four courses high. We would put up into operating position four auxiliary needles and draw four down, alternating in this way with four up and four down for the width of the fabric. Then, referring to Fig. 86, we would draw up out of operating position as shown the rise cams c, d and e, also the wing cams f and g. This would permit the alternating four auxiliary needles we have left in operating position to always stay in this position. Now, after putting on one round or two courses of, let us say, white we would rack the auxiliary plate over four needles and then put on a round of black; rack back the four needles and put on a round of white, rack the other way four needles and put on a round of black. If we could see the fabric made thus far we would find that we had a row of blocks or checks four needles wide and four courses high. For although we have put on four courses each of the black and white, which makes eight courses in all, each color has been put on its own group of four needles; therefore the whole will build up the fabric but four courses. If we continued to operate the machine in the same manner we would get alternate black and white stripes, each four needles wide.

To break them up into checks or squares we would at this point have to either skip racking once while continuing the change of carriers each round, or miss changing carriers once while continuing the rack of four needles each round. This change must of course be made every four rounds throughout the length of the fabric, or as long as it is desired to make the check. It should be remembered that it is the auxiliary plate that is racked in this case, and not the needles proper; therefore the rack does not show in the fabric. But the shifting of these alternate sets of four auxiliary needles each round causes alternate groups of four of the needles proper to knit, the set which knits depending on which way the auxiliary plate is racked.

This same check design may be made with one card properly cut by preventing the card cylinder from turning and racking, or moving the card cylinder back and forth four needles in the same manner as the auxiliary plate was moved. Or it may be made with four cards without moving either the plate or card cylinder. In this case it would be necessary to use all the auxiliary needles and lower the wing cams f and g, Fig. 86, into action.

In making a fabric on a double jacquard machine which shows the design on one side only, it is good practice to put four cards on the front cylinder properly cut to put alternate needles into operation on alternate courses, in order to prevent putting more courses on the front plate than on the back. Or to explain it in another way, the needle in the back plate that makes the white part of the design knit only on the rounds on which the white thread carrier is used, and the needles that make the black parts operate only when the carrier with the black yarn is in use.

Now it is plain that if all the needles in the front plate are permitted to knit each round we would have approximately twice as many courses on the front as on the back. This is obviated, as stated before, by using cards on the front card cylinder to push up into operation every alternate needle when moving the carriage say from left to right, and permitting these to remain idle and pushing those not operated on this course into operation on the return course from right to left. While this is desirable it is not essential, for it cannot be done on a single jacquard, though there are many nice designs and fabrics made on this machine.

Explanation of Pattern

Fig. 87 shows a fabric made on a double jacquard machine with both card cylinders in operation. Before going any further it should be understood that both the front and back card cylinders can be operated and make a new selection of needles at the end of each course, or when the carriage is at the end of its travel at both ends of the machine. This design is made by operating the card cylinders in this way. Fig. 88 is a layout of the design shown in Fig. 87. It is one complete repeat of the design as shown by the square box in Fig. 87. All the rest of the fabric is simply a repetition of this, but when grouped together on a large piece of fabric they appear entirely different.

As may be seen in Fig. 88, it would take 36 cards to make this design. In cutting the cards for this we would cut out the places shown blank and leave the card whole to push the needles into operation in the places marked by an x or an o. This cutting would of course have to be repeated the width of the fabric, or the length of each card.

The principle as explained is used on all makes of flat jacquard knitting machines, but the method used to put the needles into operation by the cards differs with the different builders. For example, one popular method is shown in Fig. 90, where the card cylinder is placed directly below the under surface of the auxiliary plate as shown at g, and acts on a short nib with the butt turned downward and extending through the plate as shown at f. With this method it is customary to use a long needle with two butts as shown in Fig. 89 at f, instead of the short one with an auxiliary needle. Also with this method the needle plate would be a single wide plate with the tricks or needle slots cut gradually deeper as they reached the lower edge, so that at the point where the lower butts of the needles come the trick is deep enough so that the needle may be depressed to bring the top of the lower butts flush, or just below, the top surface of the needle plate. When operating the machine these butts always remain in this position, therefore will not knit unless raised up and put into operation by the cards.

If we should cut a set of cards just the reverse of the set laid out in Fig. 88, that is, cut out where these are not, and leave uncut where these are cut, and put this set on the front card cylinder and operate them in conjunction with and opposite to the back set, we would have the same design on both sides of the fabric, but the colors would be reversed.