BEARDED NEEDLE KNITTING
The type of knitting instrument employed is responsible for a convenient
division of the industry according as the machines are fitted with the
latch or the bearded needle. The latch needle has already been described
when it was observed to be independent in action. Each needle is free to
prepare and complete its own loop, this being done in rapid succession
as the cams traverse the heels or butts. In bearded needle knitting the
process is quite different, and a number of separate parts require to
co-operate with the needle for stitch formation. Fig. 29 gives a clear
view of the construction of the bearded needle, also known as the spring
needle, consisting of a piece of steel wire specially tempered with one
end bent over into the form of a spring or beard. The stem of the needle
is marked S, the beard is indicated by B, and the stem has a groove D
into which the beard is pressed during loop formation. It is
satisfactory to learn that this branch of needle manufacture has always
been efficiently carried on by the British maker. The needle is usually
fixed in what is termed a lead into which it is cast in a molten
condition, each such frame having its corresponding mould according to
gauge. The lead is used as the basis of gauge for the frame and each
lead as a rule has two needles cast in it for the great majority of
machines of this character. These leads are fixed together in a bar
which lifts in sections, and to replace any needle the clamp is
unscrewed, the lead lifted out, and a new one inserted in its place.
[Illustration:
FIGS. 29, 30, 31, 32, 33
]
_Stitch Formation on Bearded Needles._—The process of stitch formation
by means of the bearded needle is indicated in the series of diagrams 30
to 33, which represent the operation as performed on a modern rotary
frame of the Cotton's Patent type. The needle is much less independent
in action than the latch variety, and to complete the making of the loop
several auxiliaries are indispensable. Of these the most important are
the presser P which in this system is stationary, and the sinker S with
its throat A and its nose B. For the knock-over of the loop is required
the aid of the discharging piece DP which is also stationary. In Fig. 30
the needle is seen in the act of descending, having just received the
thread T from the yarn-carrier and which thread has entered under the
open beard B of the needle. At this stage the loops of the fabric F are
seen hanging on the needles down on the stem and under the nose B of the
sinker. Fig. 31 shows the next operation where the needle drops still
farther and moving towards the left has its beard pressed into the
groove D, just after which the needle descends still farther and
receives the old loop from the needle stem on to its closed beard or
spring. The stage shown in Fig. 32 is known as knocking over or
discharging where the needle is noted to have moved to the right away
from the presser, whilst it has also sunk still farther between the
discharging pieces DP. These latter perform their function solely by
reason of their position, and act as supports or rests for the stitches
as they are drawn down between the pieces as indicated. In this it is
very important that the needle should draw the new stitch properly
through the old one as any defect in knocking-over results in faulty
fabric. In Fig. 33 the needle is seen to be rising once more into the
normal position ready to receive another supply of yarn from the thread
carrier. The stitch-forming process is so important that it may be well
to summarize the whole operation under various headings.
_Laying the Yarn._—This operation is performed by the thread-carrier in
the usual manner and it draws its thread across the sinker throats from
one side of the frame to the other, regular delivery of thread being
most important at this stage.
_Sinking the Loops._—This operation is illustrated in Fig. 30 where the
sinker is noted to have pushed the thread already supplied and is
sinking it over the stems, every second needle being dealt with in this
way.
_Dividing the Loops._—The sinking of the loops in the normal frame takes
place on every second needle only, and the yarn thus supplied is
distributed equally over all the needles in the process of dividing. In
this what are termed the dividing sinkers are brought forward in a body
and spread the yarn equally over all the needles. In the operation of
sinking and dividing the part of the sinker most in use is the throat,
marked A, and this is the point where wear most rapidly occurs due to
the friction of the yarn. Wearing is accelerated in the case of stiff
yarns being worked on the machine and sinkers have to be specially
tempered or hardened to give adequate service.
_Pressing and Landing._—These two operations are performed in close
succession and are illustrated in Fig. 31. At this stage the presser
comes largely into the picture, and in itself is simply a piece of steel
fixed in front of the bar in which the sinkers work. The needles tilt
somewhat to the left and push their beards against the presser, so that
the beards enter the grooves marked D in Fig. 29, and at almost the same
instant the old loops pass on to the beards or are landed. Obviously the
timing of the pressing and the landing of the loop is of the closest
description; the spring is pressed into the groove and in an
infinitesimal space of time the needle moves downwards and the old loop
slips on to the pressed beard. Immediately this is completed the needle
leaves the presser and the beard springs back to its former position
once again. In pressing a great strain is thrown on the beards of the
needles, and if the metal is soft or devoid of elasticity defective
knitting at once results.
_Knocking-over or Discharging._—This operation is shown in Fig. 32, and
consists in drawing the new yarn through the old loop and throwing off
the latter to take its place in the fabric. The new yarn is pulled
through the former stitch and the main factor in discharging is the
downward sweep of the sinker in relation to the position of the
knocking-over bit DP. These are arranged in a kind of stationary comb
and act as a rest to the loops whilst the needle is making its descent.
Again, it is seen that correct drawing through of the loop is of the
utmost importance for successful stitch formation, and knitting is
impeded if stitches which should be thrown into the fabric remain on the
needle stems undischarged.
It will be seen that the loop-forming process with the bearded needle as
agent is carried through in a series of operations, all of which must be
perfectly co-ordinated and timed in relation to each other. When it is
essential to secure the highest results in regard to fabric texture, the
bearded needle machine is chosen in preference to the ordinary form of
latch needle machine. The method of using sinkers for loop formation
induces greater uniformity of stitch as the thread is accurately served
out to the needles, and kept under perfect control from start to finish
of the operation. One great difference between this and latch needle
knitting is that the course of loops is made as a whole, and after
sinking they are divided, pressed, and discharged at the same time
across the entire width.
_Knitting on the Hand-frame._—Hand-knitted fabrics may have two meanings
attached to them, they may be worked entirely by hand on the knitting
pins where each stitch in the article is formed by hand. Again, hand
goods may be worked on the hand-frame, the earliest form of knitting
machine, where the actual operations of sinking, knocking-over, etc.,
are performed mechanically by a series of movements performed by the
hands and feet. Fig. 34 gives a view of the functional parts of a
hand-frame directly connected with the elementary operation of knitting.
This is a side elevation showing a complete jack, sinker, etc. The
action of stitch formation is identical whether made on the hand-frame
or power machine, the sequence being sinking, dividing, pressing,
landing, and discharging of the loops. In the Fig. 34 the various parts
are marked as follows: N = needle, NB = needle bar, NL = needle lead, B
= needle beard, P = presser, T = thread, TC = thread-carrier, S =
sinker, FB = falling bar, J = jack, JW = hole for jack wire, SC =
slurcock, V = spring; on the sinker S the following parts may be
distinguished: 1 = small nose or neb, 2 = large nose, 3 = sinker throat,
K = sinker belly.
_Working of the Parts._—To form a course of loops the parts mentioned
combine their action in the knitting operation, and some further
explanation may be given of the manner in which this is executed on the
hand-frame. The thread T proceeds from a bobbin at the side of the frame
and passes through the eye of the thread-carrier TC, as shown by the
dotted line. The thread-carrier has an alternate motion from left to
right and from right to left and at the same time the slurcock has its
side-to-side movement in the wake of the thread-carrier, being timed to
run just a little behind. The action of the slurcock SC is to strike the
tails of the jacks J and tilt them up so that the sinker drops on to the
yarn which has just been placed over the stems of the needles and pushes
the yarn a short distance between them. The part of the sinker acting at
this stage is the small nose 1, whilst the fabric marked F and its
stitches hang in the sinker throats 3. The sinkers are then drawn
forward in a body by handle bars in which the sinker tails are placed,
and this action pushes the sinker loops under the beards B of the
needles N. When this is completed the presser marked P is drawn firmly
down on to the beards of the needles and the sinker with a further
movement to the right pushes the old loops so that they cover the
beards. When the old stitches have been completely and securely landed
in this fashion, the presser releases its hold on the beards or springs;
the sinkers are drawn still further to the right and, with an upward
sweep of their bellies marked K, the old loops are thrown over the
needle ends and the new loops drawn through. The sinkers are then pulled
well down in front of the machine to secure the loops in their throats
3, and with a push are again replaced on the stems of the needles
previous to re-commencing all over again. The jack is fulcrummed at the
point marked JW which is a hole through which a wire is passed, called
the jack wire; the spring V is important in fixing the position of the
jack when in its non-operative position and keeps all sinkers in line
until the sidewise action of the slurcock releases them and causes the
fall of the jacks. The slurcock SC is drawn from side to side by what is
termed the slur wheel, which oscillates, and a separate cord on this
wheel makes the thread-carrier perform a similar motion from side to
side. The falling bar FB is rather important in that it determines the
size of the loop sunk on the frame. Obviously when the jacks are
released they are free to fall a certain distance, and this distance
determines the length of loop sunk between the needles of the machine.
The longer the loops, the lower are the jacks allowed to fall, whilst a
higher adjustment of the falling bar FB produces a shorter loop. The
needle N is shown to be fixed in the needle lead NL, which in turn is
fixed in the needle bar NB. These are arranged along the bar with a
given number clamped under a metal piece, and when a needle breaks this
clamp is removed at that region only which obviates needles being
uncovered for the whole width. Other points in the mechanism arrangement
to note are that the needles are horizontal and fixed, whilst the
sinkers are vertical and jacks horizontal. The presser is moveable and
the fabric proceeds downwards, there being a winding roller to take up
the fabric.
[Illustration:
FIGS. 34 and 35
]
The hand-frame is rapidly disappearing from our knitting establishments,
although this is rather due to a decline of apprentices willing to learn
the business than lack of work. Some firms of good standing in the trade
still experience an insistent demand for real hand-frame goods, as they
are unrivalled in point of quality and wearing properties. It is not
strictly true that the hand-frame makes fabrics of so much better
quality than the power machine, but owing to the higher cost of working
on the hand-frame as compared with the power machine, it is futile to
make inferior or low-grade materials by hand. Experts declare that no
fabric is equal in textural excellence to that produced on the
hand-frame. The old stocking-maker was a skilled craftsman, who in the
course of years established a close sympathy between himself and the
machine he was working; he could interpret its moods of facile
operation. Certainly he learned how to humour the machine according to
the nature of the material and in the great subtleties of "meeting the
presser" and consequent knocking-over of the loops he acquired the skill
of imparting to the article a "skin," which the connoisseur declares to
be absent from the automatic machine-made product. The hand-frame worker
was a skilled artist in the respect of shaping articles to the fit of
the individual and his pride was that any person, however far removed
from the normal, could be provided with a garment exactly suitable to
his form.
_The Power Frame._—It is outside the scope of this work to give in
detail all the various knitting mechanisms, but it is important for the
reader to have a clear idea of how the knitting process is conducted on
several standard machines, for when these basic principles have been
mastered they can be applied quickly to elucidate the method of
operation of almost any variety of machine in the whole wide range of
the hosiery machine builder. The hand-frame as invented by Lee held its
own in the forefront of the industry for many decades and was
undoubtedly a work of genius, for it was practically perfect from the
start, as succeeding efforts at improvement produced little change in
the hand-frame as such. Even after automatic machine knitting was
introduced, the machine followed closely upon the hand-frame type, all
the leading features such as sinkers, jacks and needles being placed
exactly as in the hand machine, except that the motions were produced by
a series of shafts, cams and belts.
The first big advance in knitting with the bearded needle on an
automatic machine was made possible by the invention of William Cotton
of Loughborough, which in its present-day form is one of the most
efficient means of knitting. It is the system universally adopted for
the full-fashioned trade where the garments are worked correct to size
and shape, twelve full-sized garments being possible on one machine. The
chief functional parts of this machine operated during loop formation
are given in detail in Fig. 35 where, for purposes of comparison, the
corresponding parts have been lettered similar to the parts in the
hand-frame sketch. Briefly stated these are: N = needle, B = needle
beard, NL = needle lead, NB = needle bar, S = sinker, P = presser, SB =
sinker bar, J = jack, SC = slurcock, T = thread, TC = thread-carrier, DP
= discharging piece, CB = catch bar, NP = narrowing points.
It will be noted that this machine presents a great difference in
arrangement as compared with the hand-frame, the needles being vertical,
whilst in the hand-frame they are horizontal. Hand-frame needles are
stationary in every respect whilst the needle bar of the power frame has
a finely graduated series of movements in vertical and horizontal
directions compounded to give a series of delicate sweeps in
stitch-forming. The sinker is horizontal and not attached to the jack,
the presser is rigid, whilst the fashioning points marked NP are placed
above the machine and can be brought down over the needle beards for
loop transference.
_Knitting Operations._—The general principles of loop formation on this
machine have already been described in reference to Figs. 30 to 33. The
central feature of the frame is the main shaft on which is located the
cams for giving the needle bars, catch bars, etc., their various
motions. In stitch-making the thread-carrier and slurcock move across
the frame from left to right and back again alternately, the carrier
proceeding a little distance in front of the slurcock. The slurcock has
the effect of pressing against the ends of the jacks to push forward the
sinkers which in turn press into the yarn just laid over the needles to
form a series of loops over the needle stems. The jack sinkers are
arranged alternately in the machine so that the dividing sinkers are
pushed forward in a body and the loops equally divided over the needle
stems. At this stage the needle bar cam operates and the needles descend
in a body so as to allow of the sinker loops passing under their beards,
the needles then immediately move to the left to push their beards
against the presser P placed in front of the sinker bar SB. Beneath the
sinkers on the right are placed the knocking-over bits or the
discharging pieces DP, and on the comb formed by these blades the fabric
F rests with the loops of the last course down on the needle stems. When
the needles have been pressed and the stitches landed on to the needle
beards, a further downward movement of the needle bar is made to allow
the stitches to be discharged at the needle extremities, with the arms
of the new stitches resting on the edges of the knocking-over bits. When
this is done the needles rise again to their former position as was
described in detail in connection with Figs. 30 to 33. An important
feature of this mechanism is the catch bar marked CB which has the work
of controlling the action of the sinkers and dividers during loop
formation. The catch bar, as is noted by the shape, fits into the groove
at the sinker ends and when it assumes this position it is able to work
the sinkers as desired for loop formation.