CHAPTER VII

AUTOMATIC FLAT LATCH NEEDLE MACHINES—SINGLE LOCK

THE term “automatic” as applied to this class of machine means that all the changes are made automatically, as from plain stitch to half cardigan or full cardigan, or vice versa, changing colors to make striped work, making the rack stitch and back to plain rib, changing from rib to tubular or jersey stitch, making the French rack, etc. All these changes may be made at any predetermined place in the work without any attention from the operator. The machines discussed up to this point may be presumed to have been hand machines, that is, operated by manual power. Therefore, all changes of the stitch, yarn, racking, etc., may be done to advantage at the proper time and place by the operator as the machine requires his whole attention anyway.

A prerequisite of an automatic machine is the operating of the machine by other than manual power, therefore automatic machines are first of all what are called power machines. This does not imply by any means that all power machines are automatic, but rather that all automatic machines are power machines.

Fig. 45 shows an automatic single-lock machine built by Dubied & Co. in Switzerland, designated as Type VD, which is a very good example of the automatic machine. It is operated by the belt _A_, Fig. 46, which runs it by a pulley of the clutch type which is located back of the machine. The proper movement is conveyed to the carriage through a pair of sprockets and chain as shown in Fig. 46, at _m_. The carriage is connected to the driving chain at point _m_, by the connection rod _n_, which obviously must follow the chain back and forth around the sprockets. This arrangement gives the carriage a uniform movement during the time it is operating the needles and is generally conceded as superior to the crank system of driving.

The letter _G_, Fig. 45, indicates the lever for throwing in the clutch to start the machine, and _F_ is the crank for turning the machine by hand. This crank does not turn when the machine is run by power but hangs in the position shown. The letter _S_ shows the main or controlling chain and 1 and 2 indicate the racking chains. These will be taken up in more detail later. Letter _B_ indicates an ingenious counter arrangement for counting the rounds, which permits the use of very short chains and will be explained in due course. _H_ and _K_ are yarn carriers, of which there are five altogether. The others are on the back and cannot be seen plainly. _T_ is the yoke or bridge which holds the two sides of the carriage together. There is no physical connection between the two sides of the carriage at the point where the locks are attached, but the connection is made through extensions which can be seen, and through this yoke.

On these machines the fabric is not held down by weights, hanging thereon, as in the hand machines, but by what is called a take-up roller which has means provided for adjustment to keep the desired strain on the fabric at all times. The weights which are in plain view are to hold the fabric up to and in close contact with the take-up roller through a frame with a small roller on the fabric side of the frame and the weights on the outside, which work on the lever and fulcrum principle.

An automatic machine must have a pattern chain of some kind or character to operate its automatic functions. Means provided which will be explained in what follows cause the desired change to be made at the proper time and place. The machine under discussion has a main or controlling chain made up from wire links which may be taken out or added to at will, each link measuring about 6 inches crosswise of the chain and about one-half inch lengthwise of the chain. This chain is carried by a sprocket roller at the top and is held down on this roller by its own weight, though there are guards over each end to keep it from jumping off in case of emergency. This sprocket roller is turned the distance of one full link by the carriage depressing the lever _J_, and through this medium acting on the rocker shaft _I_ (Fig. 45) which extends the length of the machine to the sprocket roller. The latter is in turn moved the distance of one link by a pawl and ratchet.

In Fig. 46 we have a view of this main chain at _S_, with the levers on which it acts shown at _a_ to _h_. These levers swing on a small shaft, at the point where they appear to end, near the center of the machine. Instead of ending there, each has an extension on the other side of this shaft which extends at an angle and reaches quite close to the chain. These levers, though only about three-eighths of an inch wide, are arranged so the angular extensions underneath come in line laterally with each other and crosswise of the chain, or lengthwise of the machine, and they, together with the space between, cover practically the whole width of the chain. These levers swing freely crosswise of the machine, but are fixed lengthwise, therefore the positions of the upper ends can be very easily moved toward the front or back of the machine, but are stationary in the direction in which the carriage moves.

Keeping this in our mind, we will now refer to the main chain shown in Fig. 46 at _S_. It will be noted that there are a number of studs affixed to the chain which project up above the chain proper. These studs may be put on at any desired spot and taken off at will. It is quite obvious that if we fix a stud on this chain at a spot in line with one of the levers, let us say at lever _a_, when the chain has moved forward to the point where this stud comes under the angular extension of the lever the position of the top of the lever would be changed. And this new position would be fixed until the carriage has been moved to the other end of the machine and turned the chain one more link. Then the lower end of the lever will drop off the stud and be returned to its former position by a spring.

It is essential that the reader get these explanations of the different parts and their functions well fixed in his mind in order to understand intelligently the relation of one to the other.

Fig. 47 is a drawing of the cams and cam plates, and Fig. 48 shows the top of the carriage with the cams or locks mounted underneath. In the Dubied machine this part of the carriage on which the locks are fixed is detachable, and either side may be taken off separately, which arrangement is very convenient at times. At the left of Fig. 48 will be seen several slides, designated by small letters, which extend through the locks at different points between the cam plate and the carriage proper, and some on the top of the carriage. These are the essence of the automatic control of the stitch forming mechanism. This principle is followed in all automatic machines of this type, although the different builders vary in the details of construction and in the methods of moving these slides, as well as the manner of operating on the cams and yarn carriers.

These slides make the proper cam or yarn guide changes by being pushed in or pulled out, as the case may be, and this is done by the levers indicated by the letters _a_ to _i_, Fig. 46. Each slide is provided with a flat spot or shoulder, as indicated at _m_ and _o_, Fig. 48, which pushes them in upon coming in contact with the proper lever as the carriage reaches the extreme left end and is clear of the needles. In order to have these slides moved in just the proper distance there are projections from the carriage underneath the slides with beveled ends, part of which may be seen in Fig. 48 at _k_ and _i_, which push the levers off the before-mentioned shoulders and release the slides at just the proper time. To explain the drawing out of these slides, it will be noted that each slide has an enlarged part or head and all have at least one right angled shoulder on the inside of the head; some have two.

It will also be noted that each one has under it a guard or extension from the carriage, which is fixed to the carriage and is stationary, as _e_ and _p_. This extension also has an enlarged part or head on the outer end, but it is different from the heads on the levers in one respect, this head has sloping shoulders on both ends instead of the right angled shoulders that are on the inside head of the slides. Where a fixed guard or extension has a sloping shoulder on both sides (not ends) they will be found to be at different distances from the carriage.

The right angled shouldered heads on the slides are made in this way so that when the proper lever (Fig. 46) is placed in its path, which is done by the studs attached to the main chain _S_, it will slide over the head and drop in back of the shoulder as the carriage moves to the left, and when the carriage moves to the right the lever catches on the shoulder and draws it out until the lever is released by being pushed out by the sloping shoulder of the extension underneath. When the fixed extension has a sloping shoulder on both sides at different distances from the carriage proper it will be found that the slide also has a right angled shoulder on both sides. This indicates that this slide may be moved to any one of three different positions, therefore has a choice of three different functions it may perform in the automatic changes.

Changing Stitch

To make the changes from plain rib to half or full cardigan, or to plain jersey, etc., the slides have inclined planes under the cam plates and these engage notches or pins on studs extending through from the cams and by this means raise the cams up into the cam plate out of action, or let them down into action as the case may be. The illustration, Fig. 47, shows them all down in the proper position to make the plain rib or cuff stitch.

To change to half cardigan stitch it would be necessary to raise cam 3_b_ up out of operation, which is done by slide _n_. Fig. 48, which in turn is moved to the proper position to accomplish this by the lever _h_, Fig. 46. This slide has three different positions, therefore three different functions to perform in the automatic changes, which are accomplished as follows: To make a half cardigan stitch a low stud (there are three heights, low, medium and high) should be placed so it will come under lever _h_. When this takes place the top end of this lever is moved to the position where it would engage the upper shoulder of slide _n_, and on the return of the carriage it would draw this slide out to its farthest point, or until it is pushed off the shoulder by the taper on that side of the guard or extension _p_. When the slide is moved to this position it raises up and holds out of operation cam 3_b_, thus causing the machine to make the half cardigan stitch. This should be readily understood from what has gone before.

To change to plain rib stitch place a medium stud under the same lever (_h_) and its top position will be changed to where it will push the slide clear in as the carriage moves to the left. On the return movement the lever will engage the shoulder on the opposite side and draw it out until released by the guard as before. This releases cam 3_b_, which drops down into working position. The fact that the sloping shoulders on each side of the stationary guards are at different distances from the carriage causes this slide, _n_, to be left in different positions according to which side the lever _h_ engages it.

In the third change, which makes the French rack or false knop stitches, it is necessary to raise up out of operation the cams 3_b_ and 3_c_. To do this a high stud should be placed to come under the same lever (_h_), which would then be moved to a position where it would come in contact with the shoulder _v_ (which is a part of the slide _n_) and would push the slide in until disengaged by another sloping guard which cannot be seen. When the lever drops back on to the chain without any studs under it it is clear of all slides; therefore will make no changes. The other slides are moved in the same way as the one just explained, but each one has the part, which make? the changes, constructed in such a manner that it will operate that particular member of the locks for which it is intended.

Changing the Yarn Carriers

There is one other change that is made by these levers and slides besides the changes in the stitch, and that is changing the yarn carriers to make stripes of different colors. This is done, not by changing the yarn in the yarn carriers as one might imagine, but by providing a carrier for each yarn needed and then changing the carriers. These carriers are shown at letter _k_, in Fig. 46. They are not fixed to the carriage but are attached to a block which slides back and forth on ways or gibs which are shown at 1, 2, 3 and 4, and reach the length of the machine. The gibs are undercut on a bevel on both edges and the block is undercut in the same way, so they dovetail together to keep the block from lifting off, yet are free to slide back and forth on the gib. These blocks have a depression or are cut out on the upper edge with a square shoulder at each end of the cut out, and the carrier is moved back and forth by a plunger which is attached to the carriage and engages these shoulders.

In Fig. 47, at letter _x_, are shown the plungers, and Fig. 48, letter _x_, shows them placed in the block and attached to the carriage. These plungers are set to pick up the desired yarn carrier by the slide, _i_, on the front, and slide, _z_, on the back. (Fig. 48.)

Racking Chains

We will leave the slides and levers for the present and give our attention to the two racking chains shown in Fig. 49 at figures 1 and 2. Inasmuch as the rack stitch is made by a part of the machine entirely separate and distinct from the locks and carriage, that is, the needle plate, obviously it is necessary to arrange means other than the levers and slides on the top of the machine to do this automatically. The mechanism used to do the actual racking is illustrated in Fig. 32. The illustration is accompanied by an explanation of the required movements. This racking cam may be seen in Fig. 49 at letter _R_. Having in mind the former explanation it is evident that to control the racking it is necessary to control the pawls only which actuate the ratchet. This is done by the racking chains shown in Fig. 49. They of themselves do no actual racking, but simply put the pawls into action or out of action, as the case may be, at the proper time. These chains hang on a sprocket roller and are moved two links at each round of the machine by the same means as the main chain, and are started and stopped automatically by studs on the main chain at any predetermined time. There are also two levers over the top of each, and it is by means of these levers that they control the pawls which actuate the racking cam ratchet through small rocker shafts.

It will be noted that the chains have studs attached, similar to the main chain, which are staggered or attached alternately near both sides of the chain. As these studs pass under and raise a lever at the top of the chain they cause a pawl to act on the racking cam ratchet, thereby making one rack.

When the carriage makes the next round the chain would have moved forward so the lever just mentioned would have dropped off its stud and the stud on the other side of the chain would move up to and under the second lever, which would cause the other pawl to act in the opposite way and therefore would rack the plate back to its starting point. If two or more racks in the same direction are desired, it would only be necessary to put two or more studs in line on the same side, but remembering that where this is done it is imperative that later the same number be placed on the other side so as to return the racking plate to its original position.

Both of these chains do the same work and in the same manner, and either one may be selected to do the racking at any time or place, but both should not and cannot be operated at the same time for there is a very ingenious arrangement which will stop the one automatically, if working, immediately when the other one starts.

The reason for providing two chains instead of one is to enable the operator to make two different kinds of rack in one garment by setting the studs on one chain for let us say a one-needle rack, and on the other for a two-needle rack. This arrangement permits the use of very short chains, as the racked pattern may repeat itself on the chain any number of times, where if a single chain were used it would be necessary to have a chain long enough to have a stud for each time the plate racked, when two patterns are required, and this would necessitate the use of a very long chain at times.

Some few years ago, when automatic machines were first brought out, all automatic functions were operated from a single chain. This meant the use of very long and unwieldy chains many times, as it was necessary to have a link in the chain for each round. It was soon realized that by stopping the chain during the time the machine was making one kind of fabric without a change, which on most work is by far the greater part, and operating it only when needed, not only much time and material in making up the chain would be saved, but also much annoyance and trouble in providing means to keep the chain from getting twisted or out of place while running would be eliminated.

Control of Automatic Changes

Most of the builders have devised means to do this and one of the best methods is the cylinder or drum idea devised by Dubied & Co., which is shown in Fig. 50. To more easily master the explanation of how this cylinder operates, it should be understood that its only function is to count the rounds and start the main chain at the proper point, the chain stopping itself after having caused the automatic changes necessary at that point.

The device consists of a cylinder about 10 to 12 inches long by about 6 inches in diameter, around which are cut two spiral grooves, the larger of which is used to attach stops and the smaller to act as a guide for the fingers _i_ and _j_, which extend down into and run in the narrow groove and carry the whole block, including the forks _k_ and _l_, forward or backward on the rods _g_ and _h_, according to which way the cylinder is turning.

The cylinder is divided in its circumference by the lines into 1,000 divisions, and is turned the distance of one division each round of the machine by means of the roller on the lug _o_, which raises the lever _a_, which in its turn raises the pawl _c_, and its duplicate on the back, which cannot be seen. It can very easily be noted how the pawl _c_ engages the outside ratchet and on being raised it would obviously turn the drum one tooth of the ratchet wheel. The back pawl operates on the center ratchet wheel and inasmuch as this ratchet wheel is cut the opposite way from the outside one, and the pawl is on the opposite side, it is plain that when the back pawl is in operation the cylinder will turn backward.

Both pawls raise each time the lever is raised, but only one at a time can engage the ratchets and the one which engages is governed by the stops _A_ or _E_ on the cylinder. This is done by two guards, one of which may be seen at _d_, while the other would be between the back pawl and its ratchet, therefore this back pawl could not operate.

These guards are mounted on a triangular or three-cornered frame which is pivoted at the center on the cylinder shaft with the guards mounted on the two lower corners, while the third corner is engaged by the lever _n_, which in turn is secured to the rod _h_. Now it is plain that if the bottom or base of this triangle is moved forward or toward the machine, the front guard would move under and disengage the front pawl while the back guard would move down and free the back pawl and allow it to operate on its ratchet wheel.

Keeping this triangular arrangement in mind we will turn our attention to the block, of which the fingers _i_ and _j_, and the forks _k_ and _l_, form a part. As noted before there are three fingers extending down to the cylinder from the block, two of which (_i_ and _j_) reach down to but do not touch the cylinder, while the third one, which is between these two, engages in the smaller of the two grooves.

The block is constructed so it must move lengthwise of the rod as one piece, but each part is free to move laterally independent of another. The block is not fixed in any manner to the top rod and the only positive connection it has with the lower rod _h_ is with a key in the center finger which engages in a keyway which is cut the full length of the rod. It should now be clear to the reader that so long as there is no obstruction placed in the path of the center finger it will simply follow the small groove and gradually move over toward the right (if the front pawl is operating and the top of the cylinder is turning away from you) until it comes to the Stop, _E_, which it will be noted lies across its path.

On account of the key in this center finger engaging the keyway in the rod _h_, it naturally follows that when the finger comes up to the stop _E_, the next movement of the cylinder will swing it away from you and this turn of the rod _h_, will swing the lever _n_, and through this will swing the triangle on which the guards _d_, are mounted, bringing the front guard _d_ up under the front pawl and at the same time will free the back pawl on the center ratchet, thereby reversing the movement of the cylinder.

Upon the return of the block to its starting point at the left end of the cylinder, its direction of movement is again reversed in the same way by the stop _A_. Stop _A_ is set at division _O_ and is never moved, but stop _E_ may be placed at any number of the divisions corresponding to the number of rounds in the garment. This point will be taken up again further along.

Now to give our attention to the side fingers _i_ and _j_. These are constructed so that the left one, or _i_, will swing freely toward you but an attempt to swing it away from you will engage the fork _k_, which by contact would swing the rod _g_, which through the connection _f_ would raise the lever _e_, and this by a pull on the cord _m_ would start the main chain in motion. The right finger _j_ works in precisely the same manner, only that it swings freely when moved away from you and starts the main chain in motion when moved toward you, by contact of the fork _l_ with rod _g_.

With the foregoing in mind it should hardly be necessary to explain that the stops _C_ and _D_ are for the purpose of putting the main chain in motion by coming in contact with the fingers _i_ or _j_; _C_ to operate when the cylinder is turning the top away from you by tripping finger _i_, and _D_ when it turns toward you by tripping finger _j_. It will be noted that the stops _A_ and _E_ have short extensions which extend forward along the side of the small groove. These cause the side fingers, _i_ or _j_, to start the main chain at the same time that the direction of the movement of the cylinder changes. If for any reason this is not desired, a stop like _B_ may be used instead of these, and then the cylinder will reverse without starting the main chain.

Going back to the setting of stop _E_, where the garment to be made has less than 1,000 rounds, it is customary to set this stop as well as the intermediate stops, like _C_ and _D_, to make a complete garment on its forward movement and a second one on its return. But if the garment should have more than 1,000 rounds, let us say 1,500, then stop _E_ would be set on division 750 and the small stops like _C_, which are for tripping the finger _i_, would be placed at the proper place to start the main chain for the automatic changes in the first half of the garment. The stops like _D_, which are for tripping the finger _j_, would do the same for the last half of the garment.

If there is no change to be made in the middle of the garment the knitter may avoid it by either one of two means; either by using a stop like _B_, which will reverse the movement of the cylinder without starting the main chain, or by using a stop like _E_, which starts the main chain at the same time it reverses the movement of the cylinder, but in this event he must put in the main chain two extra links with a stud attached for stopping the chain immediately after starting without acting upon any of its automatic mechanism.

If the fabric being made does not require the use of the cylinder all that it is necessary to do to stop it is to raise up the lever _a_, and draw the roller _b_ out against the head of its stud.

Control of Yarn

Up to this point the yarn guides and carriers have been mentioned only incidentally so we will now take them up in more detail. Where there is only one thread and guide on a machine it is a very simple matter to control it but in the modern full automatic machines, where there are several threads and guides, and they must be arranged so that any one on a single lock machine, or any two on a double lock, may be selected at will, it becomes more of a problem. There is another point that must be taken into consideration in connection with this. That is, in the automatic machines the carriage must travel the full length of the machine but much of the fabric made on these machines does not take the whole width. Therefore if the yarn carrier was carried the full length with the locks there would be at the end of each course a considerable length of yarn, reaching from the edge of the fabric to the yarn carrier, which it would be very difficult, if not impossible, to draw back through the yarn guide. There must be no slack yarn between the edge of the fabric and the yarn guide when starting to knit across on a course.

To obviate these difficulties the yarn carriers are attached to blocks which in turn are mounted on ways or bars which reach the full length of the machine and may be seen in Fig. 46, and are indicated by the figures 1, 2, 3 and 4 in white. This has been explained in part before, together with the manner of operating the carriers with plungers, but I wish to call the reader’s attention to it again as it has a direct connection with what follows.

To prevent the yarn carrier from following the locks to the end of their travel, and thereby accumulating yarn between the guide and the edge of the fabric, there is a stop placed at each end of the fabric to stop the carrier at the proper point. One of these stops may be seen in Fig. 49, at _Q_. This may be placed in any desired spot and is held in place by a pin which engages in one of the holes in the way or bar, which holes may be plainly seen.

This stop consists of a base or block which slides on to the way on the dovetail principle. On the top edge of this base there is a thin strip about 4 inches long by about one-half inch wide, which is beveled down from the top to the bottom edge on both ends. When the carriage with the yarn carrier approaches this stop the carrier comes just under this top strip and the point of the strip comes just under the end of the plunger _X_, Fig. 48, also Fig. 52, which as explained before moves the yarn carrier. As the carriage moves farther along, the plunger slides up the incline or bevel of the strip and is raised out of engagement with the shoulder on the yarn carrier block, and the carrier stops while the carriage completes the length of its travel.

Upon the return of the carriage the plunger will slide over the strip on the stop, drop into the opening of the yarn carrier block, and engage the opposite shoulder and take the yarn carrier back with it on the return course, where it will be released on the other side in the same manner as just explained.

Yarn Take-Up Spring

No matter how close to the edge of the fabric the yarn guide may be stopped, unless the yarn is kept taut the selvage will not be perfect, therefore a very insignificant appearing but quite important adjunct called the yarn take-up spring is provided to do this. There is one provided for each yarn guide and their position in relation to the machine may be seen at the top of the yarn stand in Fig. 45, while one is shown in detail in Fig. 51. The spring is a coil spring turned around the stud, _f_, and attached at the inner end. The outer end is a part of this spring straightened out as at _b_, with an eye turned in the end at _d_.

By turning the top of the stud _f_ away from you it will put more pull or tension on the spring, and by turning toward you less. The yarn is drawn from the bobbin, _e_, through an eye directly over the bobbin, then through a hole in the tension stud at _a_, then through an eye of the spring, then down through another eye in the stand at _g_, and directly to the yarn guide of the machine. The tension _a_ prevents the spring from drawing any yarn from the bobbin, therefore it will always draw the slack yarn from the yarn guide and keep it taut at all times. There must be a take-up spring for each thread in use and that means that there are sometimes as many as eight or ten on one stand.

We have had a drawing of the double lock in Fig. 40, showing the cam side with an explanation of how it works and its advantages, so now we will show only the top carriage side in Fig. 52, with its appurtenances for the automatic changes. Bear in mind that when slides or plungers are mentioned in the following explanation reference is made to Fig. 52, and when cams are mentioned reference is had to Fig. 40.

Stitch Changes

Slide _a_ operates on cams 1_b_ and 4_b_ to change from plain to cardigan, or vice versa, and is used in making the full cardigan stitch. Slide _b_ and _g_, working in conjunction with _d_ and _e_, are for changing the length of stitch, which will be explained more fully later. Slides _c_ and _f_ are for changing the yarn carriers to change colors. The exchange of carriers at the end of each course in order to keep the cotton carrier feeding into the cams that are leading (where cotton and worsted or wool is used) is another matter and should not be confused with this. Slide _h_ operates on cams 2_b_ and 3_b_ to change from plain to half cardigan, or vice versa, also on these cams together with cams 2_c_ and 3_c_ to make the French rack or false knop. Slides _i_ and _j_ operate cams 1_a_, 2_a_, 3_a_ and 4_a_ to make tubular work, or to be more explicit, they raise one pair of these cams up out of operation while the other pair knit only on one side alternately and in this way knit jersey fabric in tubular form.

To go back to slides _b_ and _g_, in order to understand this explanation it will be necessary to return again to Fig. 40. What are called the stitch cams, or cams 1 to 10, are attached to the cam plates through elongated slots, the ends of which may be seen at the top and bottom of the cams. The cams, though attached to the plate, may be easily moved lengthwise of these slots. On the under side of the plate is a coil spring with one end attached to a stud in the cams, while the other end is attached to the bottom edge of the plate. These springs will always draw the cams to the lowest end of the slots if nothing is placed in the way. Bear in mind that the bottom of the lower plate is the lower edge and the bottom of the top plate is the top edge, in the drawing.

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.

It may have been noticed in Fig. 45 that the machine illustrated has two separate fabrics on it. This is done very often when a knitter has a large machine and has no wide work to make. He simply utilizes the greater part of the machine by making two narrow fabrics.

When this is done both fabrics must be the same vertically or lengthwise of the fabric, but they may be of different widths and of different colors. This is made possible by the system of carriers and blocks mounted on ways together with the stops, as just described.

There are two carriers mounted on each way or bar, instead of one as previously explained, and stops are placed at each side of both fabrics so the plungers, either _y_ or _x_ or both, according to how many carriers are in use, will drop one carrier at the edge of one of the fabrics and pick up the other carrier to knit the course on the second fabric.