Flat Machine Knitting and Fabrics

by H. D. Buck

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.

Fig. 69.
Under Side of Carriage of Automatic Jacquard Purl Stitch Machine.

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.

Fig. 70.
Top Side of Carriage of Automatic Jacquard Purl Stitch Machine.

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.