Elastic and Non-Elastic
Narrow Fabrics
_By_ SAMUEL BROWN
and a Chapter on Narrow Fabrics
Made on Knitting Machines
_By_ WILLIAM DAVIS, M.A.
This book originally appeared serially in TEXTILE WORLD
and has been republished in this form at
the urgent request of many readers.
BRAGDON, LORD & NAGLE CO.
TEXTILE PUBLISHERS
334 FOURTH AVENUE NEW YORK
Copyright 1923
BRAGDON, LORD & NAGLE CO.
New York
Elastic and Non-Elastic Narrow Fabrics
CHAPTER I.
_Growth of Webbing Business—Attempts to Substitute Cut Products for
Individually Woven Webs Made on Gang Looms—Loom Setting to Reduce
Vibration—Capacity of Looms and Explanation of the Various Motions That
Are Employed_
When we think of the discovery of rubber vulcanization and the effect
it has had on world affairs our minds naturally turn to the big things,
such as the automobile industry with its millions of rubber tires in
constant use. These may crowd from our notice a thousand and one smaller
things of importance. It is difficult to fully realize how many comforts
and conveniences we derive from rubber and not the least among them is
the multiplicity of woven fabrics which are used both for comfort and
convenience in a variety of ways and for innumerable purposes. It is
not only in such things as garters and suspenders, with which our minds
may first associate elastic webs, that these fabrics are used, but they
find employment in a variety of other products, which are growing more
numerous all the time. Today there are in operation thousands of looms
and braiders, in which many millions of dollars are invested and in the
operation of which, together with complementary machinery, about ten
thousand people are employed.
It was about the year 1840 when the idea of weaving threads of elastic
in connection with other materials was first conceived. After long
experiments this was accomplished in the very simplest form of weaving.
New ideas were from time to time introduced, and new uses found for the
product, until now it covers a large variety of both plain and fancy
weaves, and the multiplicity of uses are so varied that few realize them
who are not closely associated with the business.
AMERICAN INDUSTRY STARTED ABOUT 1860
It was not until about the year 1860 that elastic web weaving was
introduced into this country, although for a number of years previous
England and Germany, and also France in a small way, had found here a
market for their product, particularly in cords, braids and shoe goring,
which at that particular time was fast growing in popularity. About
1860, a few looms which had been used, were brought over from England
and located at Easthampton, Mass., and the manufacture of shoe goring
commenced. The rubber thread required was for some time imported from
England. The business grew rapidly, and factories were established in
a number of cities, more particularly at Boston, Lowell and Brockton,
Mass., Bridgeport, Conn., and Camden, N. J. An unfortunate labor dispute
took place about the year 1890, which developed into a long-drawn out
strike, ultimately precipitating friction between the shoe trade and the
goring web manufacturers, which finally ended in a positive boycott of
this product from which the trade has never recovered. Most of the looms
which were up to this time devoted to shoe goring have been remodeled and
are now used in the making of other types of elastic fabrics. In passing,
it may be interesting to note that some of the looms originally brought
from England 60 years ago are still in operation and doing excellent work
along other lines.
ATTEMPTS TO USE WIDE LOOMS
Attempts have been made from time to time to weave elastics on wide
looms, the cloth being divided at intervals by open spaces in the warps
at the front reed, at either side of which spaces binding threads were
woven in. These narrow strips were spaced in the front reed according to
the different widths which might be required, and could easily be changed
to meet the varying requirements by redrawing a few threads, inasmuch
as the whole weave was uniform throughout the full width of the cloth.
Between these spaces, but at a point away from the weaving line, were
arranged stationary knives by which the cloth was cut into the requisite
widths while it was being woven, and as it gradually passed by the knife
edges. These knives were so arranged that they could be adjusted to new
positions when it became necessary to change the widths of the individual
strips.
While this method was more economical than weaving individual webs in
gang looms, the labor cost being much less, the narrow webs produced
having the cut selvages lacked the finished appearance which the
individually woven webs had. And sometimes the binding threads would
give way, so that the fabrics were not well received by the trade, and
ultimately the demand for them died out.
Attempts were made to supersede the individually woven strips in another
direction by the use of two finely woven pieces of cloth, one to form
the back, and the other to form the face of the goods, with an elastic
substance mechanically stretched out and inserted between the two. These
different parts were calendered together and afterward cut into strips
of the desired widths. This method was not without many advantages.
Strips of different widths were easily made without the costly method
of redrawing the warps in the looms. An unlimited choice of both plain
and fancy fabrics could be used, having if desired distinctly different
appearances and constructions for face and back, and this alone opened
up a wide range of possibilities. The finished cloth lent itself
admirably to fancy embossing and printing and to various other forms of
elaboration. But somehow the trade did not take to it, and this also
finally died out.
The trade ultimately settled down to the weaving of elastic goods of
all kinds, both plains and fancies, in gang looms, and the business has
steadily grown ever since along these lines.
STRAIGHT SHUTTLE AND CIRCULAR SHUTTLE LOOMS
The looms employed are very varied, inasmuch as the requirements cover
a wide range and new uses are constantly arising with new demands. The
simplest form of weaving is that employed on the making of webs such
as are mostly used for garters, and which are also used for many other
simple purposes in nearly every household. These webs are commonly known
as loom webs, lisles and cables. They are generally made on plain,
narrow, cam looms, some of which are capable of accommodating as many as
56 pieces or strips at one time.
There are two distinct types of loom employed, one of which is known as
the straight shuttle and the other the circular shuttle loom. In the
former type, the straight shuttle, in traveling across the different
spaces, takes up more room than the circular shuttle, and thus somewhat
curtails the number of pieces which can be operated in the loom, limiting
capacity of production, and relatively increasing the cost. Very few of
the straight shuttle looms accommodate more than 36 shuttles, according
to the width of the goods required. The circular shuttles travel over a
segment of a circle and cross over each other’s tracks in their movement
through the shed, as shown in Fig. 1. This permits the crowding of the
pieces of web closer together, so that many more can be accommodated in
the same loom space than when the straight shuttle is used. This type
sometimes runs as high as 56 shuttles to the loom.
[Illustration: Fig. 1.—Circular Shuttle Webbing Loom]
[Illustration: Fig. 2.—Rack and Pinion Movement for Actuating Shuttles]
PREVENT LOOM VIBRATION
These looms often are speeded as high as 180 picks per minute. To operate
at this speed with so many pieces of web and make satisfactory goods,
free from thick and thin places through irregularities of speed or
variable momentum in running, a very heavy type of loom is necessary.
They should be erected on solid foundations so as to eliminate all
possible vibration. A solid concrete floor into which timbers have been
properly set so that the feet of the looms may be securely anchored into
them is the ideal way, but where this is not practicable at least heavy
foundation timbers for anchoring the loom feet to should be arranged. The
frames of the looms should be heavy; also the main driving shaft, which
should have wide bearings so as to prolong the life of the shaft at the
wearing points and obviate loose play in the boxes.
The crankshafts must also be very heavy and there should be enough of
them so as to rigidly withstand the repeated beat of the lay without
liability to take on any loose motion, which would be fatal to the
production of perfect goods. Weight and strength here is very essential,
inasmuch as it is not practical to get a direct line from the shaft to
the lay on account of the harness movement, and they must be built to
drop below the harnesses which form makes them subject to heavy strain at
the beat of the lay. They should also be made adjustable, each arm having
a heavy left and right threaded insert, so that the length of the weaving
line may be changed to meet the varying requirements of different webs.
They should also be constructed so that any wear may be taken up.
The lay itself must necessarily be very heavy. It is generally
constructed of several thicknesses of timber of different kinds, so as
to avoid any possibility of warping and shrinkage. The shuttles used are
mostly made of applewood. While they must run smooth and be free from
the risk of slivers they must at the same time be very light so as to be
freely drawn across the multiple of web spaces. It will be easily seen
that the drawing of so many shuttles over a space of about three times
their length, at possibly 180 picks per minute, carrying and delivering
the necessary weft to the webs, each thread of weft being checked to a
certain extent by friction springs, requires great care and thought in
construction. Shuttle wood must be thoroughly seasoned by age or it will
not serve the purpose.
The shuttles themselves are very ingeniously constructed so as to
accommodate the greatest possible amount of filling, together with the
necessary space for springs to properly manipulate the tensions. Each
shuttle is bored through at either side so as to allow for the insertion
of a fine recoil spring, which is made fast at one end of the drilled
hole at the back of the shuttle. To the other end of the spring is
attached a small porcelain eye, through which is threaded the weft,
making it possible to govern and take up by the action of the spring the
loose filling which is thrown off as the shuttle passes and repasses
through the shed. These side recoil springs are not only useful for the
taking up of the loose filling but allow for a variety of threading up
methods, so as to assist in the governing of the tension of the weft at
one or both sides of the web, and thus afford a means of weaving the
goods level. They aid in correcting any tendency to long and short sided
goods, of which we will say more later.
At the back of the quill or shuttle spool is arranged another spring on
which is swivelled a porcelain device which presses against the quill,
and can be so regulated as to govern the tension. This spring is so
tempered that the most delicate adjustment of tension can be made.
RACK AND PINION MOVEMENT
The shuttles across the entire width of the loom are drawn to and fro by
what is known as the rack and pinion movement. (See Fig. 2). This method
has pretty generally superseded the old-time plan of rise and fall pegs.
The rack runs back and forth in a slot grooved in the top of the lay bed,
A, the entire length of the loom. To the rack is attached leather straps
G, or heavily woven fabric straps, with which the rack B is pulled to
and fro at each pick of the loom. The rack is of wood, having rounded
teeth-paced approximately one-third of an inch apart. Into the rack are
meshed pinions C, two to carry each shuttle E, the teeth of which are
correspondingly spaced. The rack is set into a wood carrier which is
about one inch deep and one inch wide, and the full length of the lay.
The pinions are made of either raw hide or paper fibre, and these pinions
again mesh into a series of racks D, grooved in on the under side of each
shuttle, and thus drive the shuttle to and fro across the web spaces J.
The constant travel of the driving rack running in the groove at the
top of the lay bed necessarily produces more or less wear at the bottom
of the rack. It therefore is advisable to place underneath this rack a
false bottom of wood of about ¼-inch thick, which after becoming worn by
constant use and contact with the ever-moving rack may be easily taken
out and replaced by a new one, thus keeping the rack and pinions and
shuttles at all times in proper mesh with each other.
The rack is drawn backwards and forwards by the before-mentioned straps,
which are passed over pulleys and are either fastened to the rack by
means of wood screws, or securely locked with a metal clamp designed for
this purpose. These straps are sometimes separated by a pair of cams
set on a shaft making one revolution to each two picks of the loom. The
power from these cams is first communicated to eccentrically-shaped wood
pulleys, moving backwards and forwards, which are so formed as to start
and stop the shuttles slowly, and to operate them at a higher rate of
speed during their passage through the middle of the shed. This movement
is necessary to avoid a too early entrance of the shuttle into the
weaving shed before the harness is properly settled, and also to soften
the hammering at the close of its travel so as to reduce the wear and
tear.
It might be well to note here also that this hammering is also softened
by the placing of a piece of soft rubber H at each end of the rack run,
so that the rack strikes this soft cushion each time it goes home. While
the cam method has been extensively used to produce the kind of movement
most desirable for the travel of the shuttle, it has its drawback in the
momentum produced, which it is often found difficult to control.
The Crompton & Knowles Loom Works have designed a shuttle motion which
effectively governs the desired speeds in the travel of the shuttles
while they are entering, passing through, and leaving the shed, by a
dwelling movement operated by a series of gear wheels and oscillating
slotted rocker. It is absolutely positive in action and does away with
the uncontrollable and erratic movement so often met with in the cam
drive.
MOVEMENT OF HARNESSES
Four-pick cams are all that are necessary to produce the plain webs
which are used for ordinary purposes. However, it is not the practice to
confine looms to the limitations of this capacity, but to put in either 8
or 12-pick cams. These, besides providing means to make the plain weave,
open up possibilities for a number of other weaves and combinations of
weaves, which add materially to the usefulness of the loom.
[Illustration: Fig. 3.—Direct Cam Movement]
[Illustration: Fig. 4.—Loom with Side Cam Method of Harness Control]
There are two distinct types of cam movements used in looms of this
character for the making of ordinary webs. One is known as the direct
cam drive, where the cams are fitted on a 4 to 1 shaft, as shown in
Fig. 3, which runs lengthwise of the loom and from which the power is
communicated to the harnesses through a series of levers A, rocking poles
B, levers C, and lifting wires to the harness D.
The other movement is known as the end-cam method, where a small shaft
is set at the end of the loom, running at right angles to the driving
shaft (See Fig. 4) from which it is driven by bevel gears. On this short
shaft are set the cams, usually 8 or 12 in number, which have a series of
grooves at their center so as to afford means of timing them in different
positions on a feather key which runs the full length of the shaft. These
cams operate what is known as the cam jacks, which may also be seen in
Fig. 4.
The jacks are hung at the middle and are moved backwards and forwards by
the cams, communicating movement to the various harnesses. The harnesses
are connected at both the top and bottom of the jacks. This connection at
both ends of the jacks makes it possible to run the looms at a very high
rate of speed, as there are no weights or springs to contend with, which
limits speed.
While the first described method of direct cams has some advantages
over the end cams, such looms are not nearly so economical to operate
as the end cams on account of the limited speed attainable. While the
harnesses are lifted by means of the cams they have to be pulled down by
weights or springs. The means of shed adjustment, however, enables the
attaining of a well graded shed. Furthermore, the cams themselves can be
so set on the shaft as to afford means of timing the movements of the
different harnesses so that excellent and easy shedding results may be
obtained. But the one great disadvantage is the limitation of the weaves
attainable, which limitation is largely overcome by the end-cam method.
When the direct cam movement is used, and where the goods being woven are
of such a character as to demand a very slow speed of the loom, it is
practicable to bring the harnesses down by weighting them with wide flat
weights of the requisite size. But where higher speed is required than is
advisable for weighted harnesses, springs are more desirable.
The simplest form of pulling do the harnesses is by the use of floor
blocks and direct springs. There is, however, a disadvantage in using the
direct spring on account of the pull increasing until the extreme lift
of the harness is reached, which necessarily increases materially the
power expended in operating same and makes an unnecessary strain. The
better way is to use what is known as spring jacks, which have an easier
pull than the direct spring inasmuch as the load eases off on the pull,
diminishing from the greatest pull at the start to the lightest pull at
the extreme lift on the lever, so that the load is uniformly distributed
all through the movement and less power is employed.