CHAPTER II

LATCH NEEDLE KNITTING—MAKING JERSEY CLOTH ON THE LAMB TYPE OF MACHINE

ALTHOUGH what is known as the spring beard needle was a part of the original invention of the knitting machine, and was in use more than 200 years before the latch needle was invented, I am taking up the latch needle machine first for two reasons. First, because the latch needle type of machine is most largely used and is more popular in this country today than any other type; and second, because I believe it can be more easily understood by a person who is not familiar with machine knitting.

In machine knitting of every kind there must be a needle for every loop, and therein lies the fundamental difference between machine and hand knitting. Latch needles, however, are constructed entirely different from the straight plain hand needles. Fig. 14 shows the construction of the latch needle. It will be noted by looking at the latches on the three needles that they swing freely on a pin or rivet lengthwise of the needle, but have no movement sidewise.

Types of Latch Needle

The hook, latch, rivet, cheek, throat and stem are substantially the same except in size in all latch needles, but the balance of the needle may and does vary in shape to a marked degree in the various types and makes of machines. Fig. 15 shows many of the different types of butts and shanks made, as well as the variation in the sizes of the hooks and the thickness of the needles, but it should be understood that the type of the butt and shank has no bearing on the size of the hook and stem, as each type is made in the various sizes and is governed only by the size of the yarn to be used.

Fig. 16 is a very important illustration and the reader should study it well and mentally digest every position of the needles, for here is shown a complete cycle of the movements necessary to make the knitted loop on a latch needle machine of the type in which the needles slide back and forth, lengthwise of the needle, in what are called tricks, or more commonly expressed, slots. Probably 95 per cent. or more of the latch needle machines in use today are of the type in which the needle slides back and forth in slots in the operation of forming the loops.

Explanation of Lamb Type Machine

A study of Fig. 16 should be made in connection with the photographic reproductions, Figs. 17 and 18. Fig. 18 shows substantially the whole knitting machine, while Fig. 17 is a close-up view of that part of the machine which actually does the knitting. Fig. 16 shows the principle used to operate the needles.

This type of machine was invented in 1863 by Isaac W. Lamb, a clergyman, and was made possible only by the invention of the latch needle in England about 1847. It is very simple in construction in the plain models and is the most versatile of all the knitting machines, it being possible to make on it a larger variety of stitches and articles of apparel than on any other machine. It is known as the flat or Lamb type of machine.

It has two flat or straight horizontal plates or beds about one-half inch thick by 6 inches wide, the length of which varies from 6 inches or less to 60 inches or more, according to the width of fabric it is designed to make. These plates are set in a frame, parallel to each other lengthwise, and at an angle of about 90 degrees to each other and 45 degrees to the horizontal. See Figs. 16, 17 and 20.

All flat machines of this type have two needle plates, but for our purpose of knitting jersey fabric we need but one, therefore we will imagine that there are two in Fig. 16 but the back one having no needles in it cannot do any knitting. The needles, as will be noted in Fig. 16, are placed in tricks or slots of which there may be any number from 2½ up to 18 in one inch, according to the size of the yarn to be used. The needles should fit in the slots close enough so that they will not have any chance to tip sidewise, yet they must move easily endwise. The gib _c_, _c_, is for holding the needles in the plate, and of course is removed by drawing out endwise when a needle is to be put in or taken out of the plate. The plate is secured in a frame indicated by the letter _n_ in Fig. 16, and the frame is attached to a stationary stand or table.

The cams _a_-1, _a_-2 and _a_-3 are attached to the carriage _b_, _b_, _b_, _b_, Fig, 17, at a point just below _a_-1, _a_-2 and _a_-3 and the carriage, together with the cams, rests and slides freely back and forth on the ways _c_, _c_, while the plate and needles remain stationary. The cams are secured to the carriage in a position so that they come very close to the needle plates. They should be set as close as possible and not rub the plate as they are moved back and forth.

It may be well to explain here that a cam in any machine is a piece of hardened steel of the proper shape and construction to cause some other part of the machine to make the proper movements to perform its functions. In this instance they actuate the needles by coming in contact with the butts.

It will be noted that each one of the needles from _e_ to _e_, Fig. 16, has a loop in the hook except from the point where they are rising over the cam _a_-3, and on these the loops rest on the shank. It should be understood that the fabric back of the needle plate has a weight on it, thereby giving to each loop a downward pull. The fabric and weights may be seen in Fig. 18.

Now bear in mind that the cams _a_-1, _a_-2 and _a_-3, Fig. 16, are attached to the carriage _b_, _b_, _b_, _b_, Fig. 17, at points underneath _a_-1, _a_-2 and _a_-3. These cams are moving from right to left and as the lower left hand corner of _a_-3 is below the line of the butts of the needles from _e_ to _e_, they, the needles, must of necessity slide upward in the slots along the edge of this cam. When they get to the top it will be noted that the latches of the needles are above and clear of the loops. As the cams move farther along, the cam _a_-2 comes in contact with the butts and slides them down again. As the needles move downward the hooks catch the thread _i_ which lies in their path, and as at _l_ the stitch that is on the needle closes the latch as the needle slides downward. As the needle moves farther down the hook draws a new loop through the old one, while the latch closing up the hook allows the old loop to slip over the end (needle _m_), and the pull of the fabric draws it down on to the new loop.

The thin portions of the needle plate indicated by the letter _h_ in Fig. 16, which extend upwards, are called jacks and these hold that part of the stitch called sinker loops while the needle is drawing through the new needle loop.

Below each needle is a U-shaped spring, _j_, _j_, and _k_, _k_, Fig. 16, which holds the needles up in the working position. They extend down to and around the bottom of the plate and up against the under side of the plate. The end that is under the plate is a little longer than the end that slides up in the slot below the needle. These U-springs are made so that before they are put in their places on the plate, the ends come together, so when they are spread and pushed on to the plate they act as a clamp to hold the needles in position. They are not attached to the needles, but simply clamp the plate with tension enough to hold them up or down, as the case may be, and the bottom end of the needles rests on them. This construction leaves the knitter in a position to pull d own out of working position as many needles as he may wish, therefore he may make his fabric any desired width by pulling needles down out of the working line or pushing them up into the working line, thereby adding to or taking away stitches.

The letter _d_ in Fig. 17 designates the yarn carrier through which the yarn passes, and which guides the yarn along the path of the hooks of the needles. After having moved the carriage clear across the working needles, and finishing a course of loops, the carriage is moved back in the opposite direction and another course is put on. This is done in exactly the same way except that the cams must necessarily push or slide the needles up and down on the opposite sides of the cams: i.e., the butts slide up on the right hand side of the V-cam or cam _a_-3 in Fig. 16 and down the right hand side of cam _a_-1, or stitch cam. This operation is continued until the fabric is of the desired length.

Needles are operated at a rate of speed that would make 500 or more stitches per minute per needle if the machine would keep them in continuous operation, but in practical work they make from 50 to 200 stitches per minute according to the size of the machine as more time is consumed as a rule in the movements of the machine between the stitches than is used in the actual knitting operation. On account of this speed of operation the latches of the needles must be under control at all points in the cycle of knitting; that is, from _f_ to _g_ in Fig. 16.

Control of Latches

It will be noted that needle _o_ in Fig. 16 has just started to rise and the stitch that was in the hook has opened the latch and still has it under control. When this needle gets up to the position of needle _p_ it has passed the point where the stitch can control the latch, therefore, other means must be provided or it would be very liable to fly up and close the hook, in which case it would be impossible for the hook to catch the yarn for the next stitch. When this happens we have what is called a drop stitch, and after the yarn had passed there would be no stitch on the needle.

To provide against this there is used in this type of machine a long narrow thin bristle brush set over the needles and at the proper angle and distance to just clear the latches. This brush is shown in Fig. 19. The letter a indicates the brush alone, and at _b_ is shown the brush in the fixture which carries it. The letter _c_ indicates the brush carrier. Fig. 20 is a view looking down from above the machine and shows the brushes, _a_ and _b_, set ready to operate in the machine. So as not to confuse the reader I will say here that all previous illustrations presenting this part of the machine have shown it with the brushes removed in order to make clear the operation of the needles.

A fabric made according to the foregoing explanations would be what is known as a jersey fabric (see Figs. 12 and 13), but it would be a flat piece of fabric when finished. Perhaps to make it plainer I should say that if the fabric were laid out on a table it would be a single thickness, and if it were to be made into a garment it would be necessary to double it over and sew the edges together to make it tubular, or in the form of a bag. If we wish to make the fabric tubular on the machine to save the labor of seaming it, and also prevent the unsightly seam, it would be necessary to use the needles in both plates, front and back. The cams would then be set by means provided, which will be explained later, so that when the carriage is moved in one direction, say from left to right, the front cams will operate the front needles and the back cams will be put out of operation; and when the carriage is moved from right to left, the back cams will operate the back needles and the front cams will be put out of work.

By continuing the operation of the machine in this manner of having only the front cams operate while moving the carriage in one direction, and only the back cams operate when the carriage is moved in the opposite direction, there would be produced a tubular fabric as shown in Fig. 21. The yarn must of a necessity go across from front needles to back ones, and from back ones to front ones each time the direction of the movement of the carriage is changed, thereby closing up both sides of the fabric.

Range of Jersey Fabric

The jersey type of fabric is very popular with the consuming public and is used for quite a wide range of garments in many different weights and materials. Milady may easily be dressed throughout, with the exception of shoes, in jersey cloth, and still be up to the minute with her clothes. She may have on silk stockings which are made with the jersey stitch. Her underwear, most surely is made of silk jersey fabric. Then she may wear a tricolet waist, which is silk jersey fabric, with a worsted jersey cloth suit. Also she might easily have her fall and winter coat made from the heavyweight fulled jersey cloth, and carry a heavy Shaker sweater, which is also the jersey stitch, on her motor trips into the country.

It is a far cry from the finest and lightest to the heaviest and coarsest in jersey cloth. Figs. 22 and 23 show two extremes. Fig. 22 is a sample of fine fabric and has 32 stitches to one inch; while Fig. 23 is used for what is known as the Shaker sweater and has 3½ stitches to one inch. Between these come men’s balbriggan underwear and the flat woolen underwear, the jersey bathing suits, tricolet, and the fulled jersey cloth for ladies’ suits and coats, etc. This stitch is also the basic one for medium priced knit neckties, as well as knit mittens and gloves, except the very lightest and thinnest.