How Needles Are Operated
As will be surmised after looking at the drawing, the jacks are moved forward and backward by cams operating on the butts a and a, which project above the surface of the needle plate in the same manner as the cams operate on the needle butts in the ordinary flat machine. The jacks operate the needles by catching the hook of the needles in the clutches b and b of the jacks. These needles are simply passed, so to speak, back and forth across the throat, between the needle plates, from one jack to the opposite one on each course, and in that way they reverse the direction of the draw of the loop on each course.
Fig. 60.
Looking Down at Top of Purl Stitch Machine.
We will now give our attention to Fig. 62, which shows the under or cam side of the carriage. It is understood, of course, that lengthwise of the carriage, or the direction of movement, would be what is crosswise or right and left in the illustration. It will be noted that the locks or stitch cam arrangement are, on the whole, practically the same as in the ordinary flat machine. This would apply to the cams and locks including a, h, k and g, also b, i, l and j. The bridges c and d are for another purpose.
Fig. 61.
Top of Carriage. Dubied Purl Stitch Machine.
It will be noted that while the stitch cams h and i, also g and j, are exactly opposite one another, the cams a and b are not. The bridges c and d have perfectly flat smooth surfaces except at points e and f, and here they have a concave portion about one-eighth of an inch deep. The space between bridge c and cam k, also between bridge d and cam 1, is filled by the needle gib 1, Fig. 60, and its mate on the back, which cannot be seen, when the carriage is on the machine. The reader should carefully study the points just gone over, that is, the location of the cams a and b in relation to each other, and the bridges c and d with their concave spots e and f, in order to fully grasp their relation to the jacks and needles in the operation of the machine.
Fig. 62.
Under Side of Carriage With Cam System. Dubied Purl Stitch Machine.
We will now give our attention to Fig. 60, where it will be noted that the front gib 1 is abnormally wide. The back gib is the same, and inasmuch as it cannot be seen we will assume that it is also marked 1 and hereafter call it back gib 1. Just below the center, laterally, of the front needle plate we see a row of jack butts which are in working position. In the back plate we see jack butts in every slot but they alternate with three up in working position, and three down out of working position. It should be understood clearly that any jacks that are moved to the outer edge of either plate will not operate as they are out of range of the cam system, the same as in the ordinary flat machine.
Fig. 63.
Jacks and Needles Used in the Dubied Purl Stitch Machine.
Let us now bring together the needles and jacks in Fig. 63, and the needle plates in Fig. 60. The butts of the jacks a (Fig. 63) are what we see projecting above the needle plates in Fig. 60. The hump c (Fig. 63) lies under the gib 1 (Fig. 60). The reason for having this gib extra wide is to cover this hump during most of the knitting operation in order to keep the needle captive. The depth of the needle slot is just sufficient to allow this part of the jack to slide under the gib freely without any up and down play, therefore it follows that when the hook of a needle is caught in the clutch b, as in jack number 1 in Fig. 63, that needle must move backward and forward with the jack. When the jacks are moved forward to the point where the butts would be near or against the gib 1 (Fig. 60) the hump c (Fig. 63) would be inside and clear of the gib 1, toward the center of the machine, therefore the shank of the jack being narrower than at the hump, a slight draw on the needle would free it from the jack as the clutch d, which holds the needle, is beveled off for this purpose. This being the case it follows that when the jacks are in this position the hooks of the needles may be easily pushed under and into the clutch b of the jacks. This is how the machine is filled with needles to begin with, or imperfect ones replaced with new.
It will now be necessary to study Fig. 62 in connection with Figs. 60 and 63. Referring to Fig. 62, the space between the cam k and bridge c, also cam 1 and bridge d, as noted before, is occupied by the two gibs 1 (Fig. 60) when the carriage is on the machine. The bridges c and d (Fig. 62) come down to the needle plates and the surface we see is on the same plane as the under side of the gibs 1, Fig. 60. We have just had the statement that when the butts of the jacks a (Fig. 63) were moved up to the outside and close to the gibs 1 (Fig. 60), the hump c of the jacks would be just inside and clear of the gibs 1, therefore could be raised sufficiently to slip the hook of a needle in or out of the clutch b of the jack. This is true only at a time when the carriage is not over and operating the jacks.
When these are moved up to this point by the cams the hump c of the jacks would come under the bridges c and d (Fig. 62), therefore could not raise up to release the needles except at the narrow concaves marked e and f in the bridges. These concaves, it should be noted again, are not opposite one another. The distance between the top or narrow part of cam a and cam b is such that when the butts of the jacks have moved up to this point the clutch b of both of the opposed jacks cover a hook of the needle. In looking at Fig. 62, the top half of the carriage would be the part covering the front needle plate and operating upon the front jacks, and the bottom half would do likewise on the back plate. When the carriage is at the left end of the machine, when making the purl stitch the needles should be in the front plate, and when the carriage is at the right end of the machine the needles would be in the back plate. This relative position is always the same when making the purl stitch.
I have assumed that the reader understands that a jack and a needle together would, when in a normal position as shown by the butts in the front needle plate in Fig. 60, reach just to the throat between the needle plates. Having the different parts and their relative positions in our mind we will now proceed with the modus operandi. We will assume that the carriage is at the left end of the machine, therefore the needles would be in the front needle plate and under the control of the front jacks, as the hooks would be in the clutch b (Fig. 63) of these jacks, while the hump c being under the gib of the needle plate will not allow the needles to escape. To obviate some of the difficulties the reader may have in understanding this explanation we will assume that the carriage as shown in Fig. 62 is stationary, and the plates with their jacks and needles are the parts that are moved.
The outline of the camway may be easily traced as it is practically the same as the ordinary flat machine with which the reader should be familiar and the action on the needles, through the jacks, is the same until they reach the first inside corner of the cam b. If the reader will take a straight edge and lay it on the illustration, he will find that this corner of cam b is just in line with the concave e in the bridge c, and also with the center of the flat portion of the cam a. This being the case, it follows that the center of the flat portion of the cam b must be in line with the left inside corner of cam a and the concave f in the bridge d.
It should be understood that as the needles are moving across the throat between the needle plates, the stitch or loop opens the latches, and guards are provided to keep them open until the needles are ready to draw the new loop through the previous one.
Now to return to where we left the needles and jacks at the right inside corner of cam b. The jacks of the back plate have reached their innermost position, and the heads or humps c (Fig. 63) lie under the bridge c (Fig. 62). At the point where the front jacks opposite are reaching their innermost position, the heads or humps c of the back jacks come under the concave e, which allows the hook of the needles, just coming forward from the opposite plate, to raise up the head and enter the clutch b of the jack. As they move farther to the left, the heads of these back jacks are under the plane surface of the bridge c, which secures the needles to these jacks. As the jacks start to move back toward their outermost position, the heads of the jacks of the front plate are under the concave f of bridge d. This allows the needle hooks of this end to draw out and release themselves from the jacks of this side, and be drawn through the loop to the back plate, and by this means to cast the previous loop off from the back plate toward the front one.
Upon the return from left to right, the needles are exchanged from the back plate to the front one in the same manner, only of course, the action is just opposite to that just explained. Therefore, the needles would pass through the loop from the back to the front plate, and cast off the previous loop from the front plate toward the back one. This would make the purl stitch.
While the machine was designed primarily to make this purl stitch, there can be made on it a larger variety of stitches than on any other machine, but in general practice the stitches made are limited as a rule to the purl, jersey and plain rib, 1 and 1, 2 and 2, etc. The term 1 and 1 rib means one needle in each plate alternately. The term 2 and 2 rib means two needles together alternating in each plate without a needle working between the two from the opposite plate. It is also possible to make the half or full cardigan stitch.
The jersey stitch may be made by one of two methods. First, when the needles are all in one plate move the jacks in the other plate to their outermost position, where the cams of that side cannot operate on them and the needles will stay on one side as there are no jacks operating on the other side to take them across. Second, by moving the handle b, Fig. 61, to the left. By doing this we would draw the cams a and b (Fig. 62) up into the cam plate out of working position, therefore the jacks would not move to their innermost position so the needles would not move far enough forward to meet the opposite jacks and could not be taken over into the opposite plate. This system of being able to operate any number of selected needles, or all of them, on either the purl or jersey stitch, either alone or in combination with the rack, is the base or principle used to make practically all the designed or pattern work produced on the ordinary purl stitch machine.
Fig. 61 shows the top side of the carriage. The letter a indicates the handle for operating the carriage; b is the lever for changing the stitch from purl to jersey, or vice versa, by raising out or putting into operation the cams a and b, Fig. 62. The letter c shows the lever for changing yarn carriers while d1 and d2 are the slides for changing the length of stitch. This change is made the same as has been explained for the ordinary flat machine; that is, by shifting the stops, of which there are three for each stitch cam or six on each of the slides d1 and d2.
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.
Fig. 64.
Basket Weave Design Made on Purl Stitch Hand Machine.
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.