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.
[Illustration: Fig. 45. Dubied Automatic Single Lock Machine.]
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.
[Illustration: Fig. 46. Automatic Mechanism, Dubied Machine.]
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.
[Illustration: Fig. 47. Cam Arrangement of Dubied Single Lock Machine.]
[Illustration: Fig. 48. Top Side of Carriage Directly Over Locks or
Cams, Dubied Single Lock Machine.]
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.
[Illustration: Fig. 49. Racking Chains and Cam, Dubied Automatic Single
Lock Machine.]
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.
[Illustration: Fig. 50. Counting Drum for Short Chain Arrangement,
Dubied Machines.]
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_.
[Illustration: Fig. 51. Yarn Stand and Take Up Spring.]
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
[Illustration: Fig. 52. Top Side of Carriage Directly Over Locks, Dubied
Automatic Double Lock Machine.]
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.
------------------------------------------------------------------------