Flat Machine Knitting and Fabrics

by H. D. Buck

To change the length of the stitch it is necessary to raise or lower these cams. To draw a longer stitch they would be moved toward the bottom of the plate and for a shorter one toward the top. Now it is clear that in order to change the length of the stitch automatically it is only necessary to provide stops of the proper height for them to rest on when pulled down by the before-mentioned springs. The cam studs to which the springs are attached are long enough to reach up through the carriage proper and may be seen resting on the end of the pins II, Fig. 52.

The reader of a mechanical turn of mind should be able to grasp the modus operandi of the automatic changing of the length of the stitch from the explanation up to this point, but to continue we will refer again to the pins indicated by the Roman numerals I, II, and III, Fig. 52.

It will be noted that there are a set of three of these pins for each stitch or draw cam, therefore the knitter may change to any one of three different lengths of stitch at his option by raising or lowering these pins. The pins must of course be set individually at the proper height, each one for its own length of stitch, before starting the machine.

Inasmuch as all the pins on the front side are attached to one slide, and the pins on the back are attached to another, all that it is necessary to do to change the length of the stitch is to change the pins on which the before-mentioned cam studs rest, they being held down on the pins by the coil spring between the carriage proper and the cam plate. This is done with slides b and g, in conjunction with slides e and d, which raise the cams and studs up so they will not catch between the pins while the change is being made. In the meantime slides b and g move the desired pins to the position where the studs can drop on them when the slides e and d are returned to their running position, which position allows studs to drop on their respective pins, with the exception of the pair of cams at the extreme right, which are held up for one course.

This is another ingenious and practical arrangement which deserves an explanation, but this leads us to another point which should be gone into first. That is, when the cams are changed to make a short stitch after having made a long one, the holding up of the right pair of stitch cams for one course is of no benefit. But in changing from a short stitch to a long one, inasmuch as the right pair of stitch cams pass over the needle butts before the new course is made, if they were allowed, preparatory to drawing a longer stitch in the next course, to drop down to a point below where the previous stitch was drawn, they would ride on the butts of the needles and cause undue strain on the stitches of that course and would be very liable to break them, thereby making holes in the fabric. This is prevented by holding up these two cams one course. This is done by providing two catches to receive and hold them when they are raised at the left of the machine, but when the carriage is moved to the extreme right of the machine the two small levers, l and k, come in contact with two studs and release the catches, and allow the two cams to drop down on their respective pins.

It has been explained that in making what are known as cotton backs and like fabrics the cotton yarn, or yarn that must show on one side only, must at all times be fed in the locks that are in the lead, on a double lock machine, while the worsted or wool yarn which shows on the other side must feed into the following pair. To do this the yarn carriers must be exchanged at the end of each course. To explain how this is done we will refer to Fig. 52, where the plungers that engage the yarn carrier blocks and moves them back and forth with the locks, are shown at x and y.

These plungers never take more than two carriers at one time. In these machines there may be four or more bars or ways for yarn carriers, and in the preceding explanation of how the yarn carriers are stopped we assumed that the carriers in question were being operated on the lower ways by the outside end of the plungers x. For this present explanation we will assume that we are using the carriers on the top bar or way, and they would be operated by the end of the plungers towards the center of the carriage.

It will be recalled that when the yarn carrier block comes to the stop at the edge of the fabric, the plunger is raised out of engagement with its shoulder, and the block stops while the plunger passes on. When the carrier block that is being moved across by the plunger in the lead stops, the one that follows will also pass over the block without moving it, as the outside end of the block is beveled off to compel this.

It will be noticed that the inside ends of the back plungers at y are flattened, and the flat sides are at right angles to the travel of the carriage. Now we will assume the carriage is traveling from right to left, and the cotton carrier is being moved along by the plunger in the lead, or y on the left. When this carrier comes to the stop on the left this plunger leaves it there and passes on, also the plunger on the right will pass on over the carrier block. But upon the return of the carriage moving toward the right the first plunger coming in contact with the yarn carrier block, which would be y on the right and which would now be in the lead, would engage the shoulder of the block and take it across.

It will be noted that the two front plungers are also flattened at x, but are different from the back ones in this respect; the inside flat is at right angles to the travel of the carriage while the outside flats are at an angle of about 45 degrees. The yarn carrier operated on this side is stopped at the edge of the fabric with the plungers passing over and beyond it the same as the back one. But upon the return of the carriage the first plunger cannot pick up the carrier block as the side of the plunger coming in contact with the shoulder of the block is beveled off and cannot catch, but when the second plunger comes along with its flat side at right angles to its movement, it will engage the shoulder of the carrier block and take it along.