Flat Machine Knitting and Fabrics

by H. D. Buck

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.