4. _Dye baths_, are distinguished into two classes; the colouring bath,
and the dyeing bath. The former serves to extract the colouring matters
of the different substances, with the exception of madder, which is
always used in substance, and never as an extract, infusion, or
decoction. In all these cases, when the colour is extracted, that is,
when the dye bath is completed by the degree of heat suited to each
substance, it is then allowed to cool down a certain way, and the cotton
is worked or winced through it, to get the wished-for tint. This is what
is called the dye bath. Several colouring baths are made in the cold;
and they serve to dye also in the cold; but the greater part require a
heat of 90° or 100° to facilitate the penetration of the stuffs by the
colouring particles. The description of the several dye baths is given
under the individual dyes.
5. _Of the washing after the dyeing._--The washing of the cottons after
they have received the dyes, is one of the most important operations in
the business. If it is not carefully performed, the excess of colour not
combined with the fibres, is apt to stain whatever it touches. This
inconvenience would be of little consequence, if the friction carried
off the colour equally from all the points; but it does not do so, and
hence the surface appears mottled. A well-planned dye house should be an
oblong gallery, with a stream of water flowing along in an open conduit
in the middle line, a series of dash wheels arranged against the wall,
at one side, and of dyeing coppers, furnished with self-acting winces or
reels, against the other. In such a gallery, the washing may be done
either by hand, by the rinsing machine, or by the dash wheel, according
to the quality of the dye, and the texture of the stuffs. And they may
be stripped of the water either by the jack and pin, by the squeezing
roller, or by the press. Wooden pins are placed in some dye-houses on
each side of the wash cistern or pool. They are somewhat conical, 1-1/2
foot high, 3-1/2 inches in diameter at the base, 1-1/2 at the top, are
fixed firmly upright, and at a level of about 3 feet above the bottom of
the cistern, so as to be handy for the workmen. See BRAZIL WOOD, FUSTIC,
MADDER, BLACK DYE, BROWN DYE, &c., as also BLEACHING, BRAN, CALICO
PRINTING, DUNGING, DYEING, &c.
COTTON MANUFACTURE. (_Filature de Coton_, Fr.; _Baumwollespinnerei_,
Germ.) Cotton is a filamentous down, which invests the seeds of the
plant called _gossypium_ by Linnæus, and placed by him in the class
_monadelphia_ and order _monandria_, but belonging to the natural family
of _malvaceæ_. It has a cup-shaped calyx, obtusely five-toothed,
inclosed in a three-cleft exterior calyx; the leaflets are united at
their base, of a heart shape and toothed; stigmas three to five; capsule
three to five celled and many-seeded; seeds bearing a downy wool.
Thirteen species are described by Decandolle, but their characters are
very uncertain, and no botanist can assign to a definite species of the
plant, the very dissimilar staples of the cotton filaments found in
commerce. The leaves are generally palmate and hairy; and the blossoms
are large, and of a beautiful yellow. The _gossypium religiosum_ of
Tranquebar has white blossoms in some of its varieties, to which,
probably, the white cotton of Rome, cultivated in the Jardin des Plantes
at Paris, belongs. The filaments differ in length, flexibility,
tenacity, and thickness, in different cottons, whence the great
differences of their value to the cotton-spinner, as the prices current
in the market show. Thus, at Liverpool, on the 1st of December, 1835,
the following values were assigned to the following cottons:--
_s._ _d._ _s._ _d._
Sea-island 1 6 to 2 6
Demerara and Berbice 0 9 1 0
Pernambuco 0 10-3/4 1 1-1/2
Egyptian 0 11-1/2 1 2-1/2
New Orleans 0 7-1/8 1 0
Bahia 0 8-1/4 0 10
Upland Georgia 0 7-1/8 0 11-1/2
West Indian 0 7-3/4 0 9
Surat 0 6-1/8 0 8
Madras 0 6-1/2 0 8
Bengal 0 5-1/4 0 6-1/2
But it is to be observed, that there are varieties of the Sea-island
Georgian cotton, so highly prized by the spinner of fine yarn, as to
fetch 3_s._, 4_s._, or even 5_s._ per pound.
The filaments of cotton, when examined with a good microscope, are seen
to be more or less ribbon-like, and twisted; having a breadth varying
from 1/800 of an inch in the strongest Smyrna or candle-wick cotton of
the Levant, to 1/2500 of an inch in the finest Sea-island.
The main distinction between cottons in the pod, is that of the black
seeded, and the green seeded; for the former part with their downy wool
very readily to a pair of simple rollers, made to revolve nearly in
contact, by the power of the human arm; while the latter retain the wool
with much force, and require to be ginned, as the operation is called,
by a powerful revolving circular saw-mechanism, usually driven by horse
or water power. After the cotton wool is thus separated from the seeds,
it is packed in large canvas bags, commonly with the aid of a screw or
hydraulic press, into a very dense bale, for the convenience of
transport. Each of the American bags contains about 340 lbs. of cotton
wool. When this cotton is delivered to the manufacturer, it is so foul
and flocky, that he must clean and disentangle it with the utmost care,
before he can subject it to the carding operation.
[Illustration: 317]
_Fig._ 317. A B, is a roller, about 9 inches in diameter, which revolves
in the direction of the arrow. This cylinder consists of a parallel
series of oblique pointed circular saws made fast to one axis, and
parted from each other by wooden rings nearly one inch and a half in
thickness. Above the cylinder is a kind of hopper E F, into which ginner
throws the seed cotton, which falls upon a grating, up though which
small segments of the saw-teeth project, so as to lay hold of the fibres
in their revolution, and pull them through, while the seeds being thus
separated, roll down the slope of the grid, to be discharged from the
spout I K. M is a cylindrical brush placed below the grating, which
revolves against the saw teeth, so as to clear them of the adhering
cotton filaments.
The _willow_, which was originally a cylindrical willow basket, whence
its name, but is now a box made of wood, with revolving iron spikes, is
the first apparatus to which cotton wool is exposed, after it has been
opened up, picked, and sorted by hand or a rake, in what is called a
_bing_. The willow exercises a winnowing action, loosens the large
flocks, and shakes out much of the dirt contained in them. The frame of
the willow is about 2 feet wide, and turns with its spikes at the rapid
rate of 600 revolutions per minute, whereby it tosses the cotton about
with great violence. The heavy impurities fall down through the grid
bottom. It is exposed, however, for only a few minutes to the action of
this machine. For factories which work up chiefly the coarser and fouler
cottons of India, and Upland Georgia, the conical self-acting willow,
as constructed by Mr. Lillie at Manchester, is much employed. In it,
the cotton is put in at the narrow end of the truncated cone, which,
being spiked, and revolving rapidly within a nearly concentric case upon
a horizontal axis, wafts it on towards the wide end, while its
impurities are partly shaken out through the grid or perforated bottom,
and partly sucked up through revolving squirrel wire cages, by the
centrifugal action of a fan. This is a powerful automatic engine,
deserving the study of the curious, and is as safe as it is powerful.
The cone of this huge machine makes from 400 to 600 turns per minute,
and will clean 7200 pounds, or 24 bags, in a day.
After shaking out the grosser impurities by the willow, the cotton
spinner proceeds to separate each individual filament of cotton wool
from its fellow, so as to prepare it for carding, and to free it from
every particle of foreign matter, whether lighter or heavier than
itself. This second operation is performed by what are called batting
(_beating_), scutching, and blowing machines, which are all now much the
same, whatever difference of signification the name may have. Indeed,
each machine not only beats, scutches, but blows. _Fig._ 318. exhibits a
longitudinal section of a good blowing engine of modern construction.
The machine is about 18 or 19 feet long, and three feet across within
the case. The whole frame is made of cast-iron, lined with boards,
forming a close box, which has merely openings for introducing the raw
cotton wool, for taking out the cleansed wool, and removing the dust as
it collects at the bottom. These doors are shut during the operation of
the machine, but may be opened at pleasure, to allow the interior to be
inspected and repaired.
[Illustration: 318]
The introduction of the cotton is effected by means of an endless cloth
or double apron, which moves in the direction of the arrow _a a_, at the
left end of the figure, by passing round the continually revolving
rollers at _b_ and _c_. The two rollers at _e_, being the ones which
immediately introduce the cotton into the jaws, as it were, of the
machine, are called the feed rollers. The batting arm, or revolving
diameter, _f e_, turns in the direction of the arrow, and strikes the
flocks violently as they enter, so as to throw down any heavy particles
upon the iron grating or grid at _n_, while the light cotton filaments
are wafted onwards with the wind, from the rotation of the scutcher in
the direction of arrow _a´_, along the second travelling apron, upon
which the squirrel cage cylinder presses, and applies the cotton in the
form of a lap. Above the cylindric cage _h_, which turns in the
direction of its arrow, there is a pipe _k_, the continuation of the
case _i_. This pipe, though broken off in the figure, communicates by a
branch pipe with an air-sucking fan ventilator, not seen in this figure,
but explained under FOUNDRY. The cage _h_, by its rotation, presses
down, as we have said, the half-cleaned cotton upon the cloth _a´_,
which carries it forward to the second scutcher _f´_, by the second set
of feed rollers _e´_. The second scutcher throws down the heavy dust
upon the second grid _n´_, through which it falls upon the bottom of the
case. The first scutcher makes about 1280 strokes of each of its two
arms in a minute; the second 1300. The feed rollers for each are fluted.
The feed cloth is either sustained by a board, or is made of parallel
spars of wood, to secure it against bagging, which would render the
delivery of the cotton irregular. The feed rollers make 8 turns in the
minute, and as their diameter is 1-1/2 inches, they will introduce 8
times their circumference, or 37·7 inches of the cotton spread upon the
apron in that time. Upon every 12th part of an inch of the cotton,
therefore, nearly 3 blows of the scutcher arm will be applied. The
second feed rollers move relatively with more slowness, so that for
every 2·4 blows of the scutcher, only one twelfth of an inch of cotton
wool is presented.
The fan is inclosed in a cylindrical case. The wings or vanes revolve
from 120 to 150 times in the minute; and while they throw the air out
with nearly this velocity at their excentric outlet in the
circumference, they cause it to enter, with equal velocity, at the
centre. With this centre the squirrel cage is connected by a pipe, as
above stated. The sound filaments of the cotton are arrested by the
sieve surface of the cylindric cage, and nothing but the broken
fragments and the light dust can pass through.
The cotton wool in the blowing machine is wafted by the second scutcher
into the space _x_, _w w_, provided with a fine grid bottom; or it is
sometimes wound up there by rollers into a lap.
In _fig._ 318. an additional ventilator is introduced beneath at _m_, _o
o_, to aid the action of the scutchers in blowing the cotton onwards
into the oblong trough _a_. The outlet of that fan is at _t_; and it
draws in the air at its axis _q_. _u_ and _v_, are two doors or lids for
removing the cleaned cotton wool. This last fan is suppressed in many
blowing machines, as the scutching arms supply a sufficient stream of
air. The dotted lines show how the motion is transmitted from the first
mover at _s_, to the various parts of the machine. 6´ 6´ represent the
bands leading to the main shafting of the mill. A machine of this kind
can clean fully 600 pounds of short-stapled cotton wool in a day, with
the superintendence of one operative, usually a young woman, to
distribute the cotton upon the first feed cloth.
[Illustration: 319]
The second Blowing machine is usually called a _lap_ machine, because,
after blowing and scutching the cotton, as above described, it
eventually coils the fleece upon a wooden roller at the delivering end
of the apparatus. It is sometimes also called a _spreading machine_. A
section of it is shown in _fig._ 319. The breadth of this machine is
about 3 feet as the lap formed is prepared for the usual breadth of the
breaker cards, namely 3 feet. Where the cards are only 18 inches broad,
the lap machine is also made of the same breadth. In the figure we see
the feed-cloth, the scutching barrel, the squirrel suction, and
spreading cage, and the rollers for coiling up the lap. The lever shown
below is for removing the pressure weight from the axis of the lap
rollers, when a full one is to be removed, and replaced by an empty one.
_m_, at the top, is the commencement of the pipe which leads to the
suction fan, or ventilator. The thickness of the lap in this machine
must be nicely regulated, as it determines, in a great measure, the
grist of the card ends, and even the rovings. In 12 hours such a lap
machine will prepare 650 pounds of cotton.
[Illustration: 320]
_Fig._ 320. is the first scutching machine, now never seen except in the
oldest factories. A B is the feed cloth; G H and M N are the two
scutcher frames.
_Carding_ is the next operation in a cotton factory. Cards are destined
to disentangle the individual filaments from each other, and to lay them
lengthwise, instead of being doubled up and convoluted, as they usually
are in leaving the blowing and lap machines. Carding consists in the
mutual action of two opposite surfaces, which are studded thick with
oblique angled hooks. The wires of which these hooks are made must be
very hard drawn in order to render them stiff and elastic. The middle
part of the figures shows one of the staples or double teeth, the
structure of which has been partly explained under CARD. Suppose _a_,
_fig._ 321. to be a piece of a card fillet, and _b_ to be another piece,
each being made fast with pins to a board; the teeth of these two cards
are set in opposite directions, but are very near together, and
parallel. Now suppose a flock or tuft of cotton placed between two such
bristling surfaces. Let _a_ be moved in the direction of its arrow, and
let _b_ be moved in the opposite direction, or even let it remain at
rest. Every filament of the cotton will be laid hold of by each set of
teeth, when their surfaces are thus drawn over each other; the teeth of
_a_ will pull them in a forward direction, while those of _b_ will tend
to retain them, or to pull them backwards. The loops or doublings will,
by both movements, be opened or drawn out, so that the flocks will be
converted into rows of parallel filaments, lying alongside or before
each other. Each tooth will secure to itself one or more of them, and by
the friction of its sides, as well as the hooks of its points, will draw
them to their utmost elongation. Though one stroke of the opposite cards
be inadequate to produce this equable arrangement, yet many repeated
strokes must infallibly accomplish the end in view, of laying the fibres
parallel.
[Illustration: 321 322]
Let us suppose this end effected, and that all the fibres have been
transferred to the card _a_, a transverse stroke of _b_ will draw over
to it a certain number of them, and indeed at each stroke there will be
a new partition between the two cards, with increased parallelism, but
still each card will retain a great deal of the cotton. To make one card
strip another, the teeth of one of them must be placed in a reverse
position, as shown in _fig._ 322.
If _a_ be now drawn in the direction of its arrow along the face of _b_,
it will inevitably comb out all, or almost all, the filaments from it,
since the hooks of _b_ have, in this position, no power of retaining
them. Even the doubled fibres or loops will slip over the sloping point
of _b_, in obedience to the traction of _a_. By considering these two
relative positions of the cards, which take place in hand cards, simply
by reversing one of them, any person will be able to understand the play
of a cylinder card against its flat top, or against another cylinder
card, the respective teeth being in what we may call the teazing
position of _fig._ 321.; and also the play of a cylinder card against
the doffer cylinder, in what may be called the stripping position of
_fig._ 322.
Cylinder cards, so essential to the continuity and dispatch of cotton
factory labour, were the ingenious invention of Lewis Paul of
Northampton, but were greatly improved and brought into nearly their
present operative state by Sir Richard Arkwright. A carding engine
consists of one or more cylinders, covered with card-leather (sometimes
called card cloth), and a set of plane surfaces similarly covered, made
to work against each other, but so that their points do not come into
absolute contact. Some cards consist entirely of cylinders, the central
main cylinder being surrounded by a series of smaller ones called
urchins or squirrels. These are used solely for preparing the coarser
stapled cotton, and sheep’s wool for the wool spinner.
_Fig._ 323. represents a card of excellent construction, which may be
called a _breaker_ and _finisher_, as it is capable of working up the
fleece roll of the lapping machine directly into a card-end or riband
fit for the drawing machine. In fine spinning mills there are always,
however, two cards; one coarser, called a breaker, which turns off the
cotton in a broad fleece of extreme thinness, which is lapped round a
cylinder; and constitutes the material presented to the finisher card,
which has teeth of a finer construction.
[Illustration: 323]
_a_ is one of the two upright slots, which are fixed at each side of the
engine for receiving the iron gudgeons of the wooden cylinders round
which the fleece of the lapping machine is rolled. The circumference of
this coil rests upon a roller _b_, which is made to turn slowly in such
a direction as to aid the unfolding of the lap by the fluted cylinders
_e_. The lap proceeds along the table seen beneath the letter _c_, in
its progress to the fluted rollers, which are an inch and one-sixth in
diameter, and have 28 flutings in their circumference. _g_ is a weight
which hangs upon the axis of the upper roller, and causes it to press
upon the under one: _f_ is the main card drum; _g g g_, the arch formed
by the flat top cards; _h_, the small card cylinder for stripping off
the cotton, and therefore called the doffer, as we have said; _i_, the
doffer-knife or comb for stripping the fleecy web from the doffer; _k l
q m_, the lever mechanism for moving these parts. At _d_ there is a door
for permitting the tenter to have access to the interior of the engine,
and to remove whatever dirt, &c. may happen to fall into it. In _fig._
324. we see the manner of fixing the flat tops _g g_ over the drum; and
for making the matter clearer, three of the tops are removed. Upon the
arched cast-iron side of the frame, a row of strong iron pins _k_ are
made fast in the middle line; and each top piece has, at each of its
ends, a hole, which fits down upon two such opposite pins. _l l_ are
screws whose heads serve as supports to the tops, by coming into contact
with the bottom of the holes, which are not of course bored through the
wood of the tops. By turning the heads of these screws a little the one
way or the other, the pins may be lengthened or shortened in any degree,
so as to set the tops very truly in adjustment with the drum teeth
revolving beneath them, _h´_ is the small runner or urchin, and _i´_ the
large runner; both of which are spirally covered from end to end with
narrow card fillets, in the same manner as the doffer. The main drum is
on the contrary covered with card cloth, in strips laid on parallel to
its axis, with interjacent parallel smooth leather borders. The teeth of
these several cards are set as represented in the figure, and their
cylinders revolve as the arrows indicate. The runners as well as the
doffer cylinder may be set nearer to or farther from the drum _f_; but
the screws intended for this adjustment are omitted in the drawings, to
avoid confusion of the lines.
The card-end or fleece taken off the doffer _h_ by the crank and comb
mechanism _i k m_, passes through the tin plate or brass funnel _n_,
_fig._ 323., whereby it is hemmed in and contracted into a riband, which
is then passed through between a pair of drawing rollers _o_. It is next
received by the rollers _u v_, which carry it off with equable velocity,
and let it fall into the tin cans placed below, or conduct it over a
friction pulley, to be wound along with many other card-ends upon a lap
roller or large bobbin. The latter mechanism is not shown in this
figure. A sloping curved tin or brass plate, channelled or ridged along
its surface, conducts the card ribands separately; there are two smooth
iron rollers for condensing the several ribands, and a wooden pin round
which the ribands are lapped, resting between two leather-covered
rollers, one of which receives motion from mill geering, and imparts it
by friction to the lap roller over it. The iron ends of the lap roller
lie in upright slots, which allow them freedom to rise as the roller
gets filled with fleece.
The two pairs of rollers at _o_, effect the extension of the card-end,
and reduce its size. The under rollers are made of iron and fluted; the
upper ones are also made of iron, but they are covered with a coat of
leather, nicely glued on over a coat of flannel, which two coats render
them both smooth and elastic. Two weights, _w_, press the upper
cylinders steadily down upon the under ones. Between the first and
second pair there is a certain interval, which should be proportioned to
the length of the cotton staple. The second, or that furthest from the
funnel, revolves with greater velocity than the first, and therefore
turns out a greater length of riband than it receives from its fellow;
the consequence is a corresponding extension of the riband in the
interval between the two pairs of rollers.
[Illustration: 324]
The motions of the several parts of the engine are effected in the
following way. The band, _p p_, _fig._ 324., which comes down from the
pulley upon the main shaft near the ceiling of the work-room, drives, by
means of the pulley _q_, the drum _f_, _fig._ 323., with a velocity of
from 120 to 140 revolutions in a minute. From another pulley _r_, on the
axis of the drum, the axis of _t_ is driven by the band _s_ working
round the pulley _t_ on its end. This shaft drives the crank and lever
mechanism of the stripper knife _i_. A third pulley of the same size as
_r_ is fixed just within the frame to the other end of the drum, and
from it a crossed or close band _r´_ goes to a pulley upon the small
runner _h´_, to give this its rapid rotation. Upon the opposite end of
the engine in _fig._ 323., these wheels and pulleys are marked with
dotted lines. Here we may observe, first, a pulley _y_ upon the drum,
and a pulley _a´_, which receives motion from it by means of the band
_z_. The axis of _a´_, carries in front a pinion _m´_, which sets in
motion the wheel _n´_. The latter imparts motion, by means of a pinion
and intermediate wheel _o´_, to the wheel _h_ on the doffer cylinder,
and consequently to that cylinder on the one hand; and it turns, by the
carrier wheel _p´_, a wheel _x_, whose axis is marked also with _x_ in
_fig._ 323., upon the other hand. The axis of _x´_, _fig._ 323.,
carries, towards the middle of the engine, a very broad wheel, which is
represented by a small dotted circle. The toothed wheel _v_ of the
smooth roller _v´_, _fig._ 323., and the two toothed wheels _o o_,
_fig._ 324., of the under rollers _o o_, _fig._ 323., work into that
broad wheel. The wheel of the second or delivery fluted roller is seen
to be smaller than that of the first, by which means the difference of
their velocities is obtained. The large runner _i_ is driven from the
main drum pulley, by means of the band _s´_, and the pulley _u´_, _fig._
323. The said band is crossed twice, and is kept in tension by the
pulley _t´_, round which it passes. The motion of the fluted rollers
_e_, which feed in the cotton fleece, is effected by means of a bevel
wheel _b´_ on the end of the doffer, which works into a similar wheel
_c´_ on the oblique axis _d´_ (dotted lines across the drum), of the
pinion _e´_ upon the lower end of the same axis which turns the wheel
_f´_, upon the under feed roller.
Each of the feed rollers, _fig._ 324., bears a pinion _e e_ at one end,
so that the upper roller turns round with the under one. The roller _b_,
_fig._ 323., is set in motion by means of its wheel _x´_; which is
driven by a wheel _v´_ on the other end of the under feed roller,
through the intervention of the large carrier wheel _w´_. The original
or first motion of _b_ must be as quick as that of the fluted feed
rollers _e_, in order that the former may uncoil as much lap as the
latter can pass on.
The annexed table exhibits the proper velocities of the different
cylinders and rollers of the carding engine, which, however, are not
invariable, but may be modified according to circumstances, by changing
the pinions _e´_, _fig._ 323., and _w´_, according to the quality or
length of the cotton staple. The velocities stated in the table will be
obtained when the pulley _a´_, _fig._ 323., is made greater than _y_ in
the proportion of 3 to 2, and the wheels and pinions have the following
number of teeth: _m´_, 18; _n´_, 50; its pinion, 18; _h_, 128; _x_, 24;
the broad wheel upon the shaft of _x_, 37 teeth; the wheel _o_ of the
first fluted roller, 35; that of the second, 21; _v_, 44; _b´_ and _e´_,
54; _e´_, 10; _f´_, 63.
+--------------------------+--------+----------+-----------+---------+
| Names of the parts. |Diameter| Circum- |Revolutions|Velocity.|
| | in | ference | in one | |
| |inches. |in inches.| minute. | |
+--------------------------+--------+----------+-----------+---------+
|Drum _f_ | 35 | 109·9 | 130 | 142·87 |
|Doffer _h_ | 14 | 43·96 | 4·38 | 192·5 |
|Runner or urchin _i´_ | 6·25 | 19·62 | 5· | 98·1 |
|Ditto _h´_ | 3·5 | 11· | 470· | 5170· |
|Fluted feed roller _e_ | 1·167 | 3·664 | 0·696 | 2·55 |
|First drawing roller _o_ | 1· | 3·14 | 68·71 | 215·75 |
|Second ditto | 1·167 | 3·664 | 114·52 | 419·6 |
|Smooth delivery roller _v_| 2·5 | 7·85 | 54·66 | 429·08 |
+--------------------------+--------+----------+-----------+---------+
The operation of the runners, _h´_ and _i´_, becomes very plain on
comparing their speed with one another and with that of the main-drum,
and taking into account the direction of the card teeth. The cotton
wool, taken off from the feed-rollers by the drum, is caught by the
opposite teeth of the large runner _i´_, which, on account of its slower
surface rotation (98 inches per minute) may be considered to be at rest
with reference to the drum, and therefore, by holding the cotton in its
teeth, will commence its carding. The small runner _h´_, in consequence
of its greater surface velocity (5170 inches per minute) will comb the
cotton-wool back out of the teeth of the large runner, but it will give
it up in its turn to the swifter teeth of the drum, which, in carrying
it forwards, encounters the teeth of the top cards, and delivers up the
filaments to their keeping for some time. We thus see how essential the
runners are to the perfection as well as to the acceleration of the
carding process for ordinary cotton wool, though for the slenderer and
longer filaments of the sea-island kind they are not so well adapted. In
cleaning the carding-engines the little runner must be looked to every
time that the drum is examined. The large runner and the doffer require
to be cleaned together. The quantity of cotton spread upon the
feed-cloth, the velocity of it, and of the drawing-rollers, must all be
carefully adjusted to the grist of the yarn intended to be spun.
[Illustration: 325]
Suppose the sizes and velocities to be as represented in the preceding
table, that the engine is a double card 36 inches broad, and that it is
furnished with a lap from the lap-machine of which 30 feet in length
weigh 5 lbs. In one minute the surface of the feed-rollers, _e_, passes
2·55 inches of that lap onwards; in the same time the main drum _f_ will
work it off. To card the whole 30 feet, therefore, 141 minutes, or 2
hours and 21 minutes will be required. In this time the circumference of
the rollers, _u v_, moves through a space of 141 × 42,908 in. = 5042
ft., and delivers a card-end of that length, weighing 5 lbs., _minus_ 6
per cent. for waste, that is 4 lbs. 11-1/2 oz. One pound will form a
riband 1072 feet long, being, according to the English mode of counting,
about number 1/3, or 0·357. The extension of the cotton-fleece to this
degree proceeds as follows:--In the 141 minutes which the feed-rollers
take to introduce the 30 feet of lap, the doffer, _h_, makes 617·58
revolutions, and the comb, or doffer knife, _i_, detaches from the
doffer teeth, a thin fleecy web of 2262 feet in length. The first
drawing pair of fluted rollers, by its quick motion, with the aid of the
funnel, _m_, converts this fleece into a riband 2535 feet long. The
second pair of the fluted rollers extends this riband to 4390 feet,
since their surface velocity is greater than the first pair in that
proportion. The slight elongation (of only 112 feet, or about 1/44)
which takes place between the delivery fluted rollers and the smooth
cylinders, _v_, _u_, serves merely to keep the card-end steadily upon
the stretch without folding. _Fig._ 325. is a plan of the card and the
fleece, where _h_ is the cylinder, _n_ is the funnel, _u_ the pressing
rollers, and _h´_ the card-ends in the can.
[Illustration: 326 327]
_Figs._ 326, 327. represent skeletons of the old cards to facilitate the
comprehension of these complex machines. _Fig._ 326. is a plan; F is the
main drum; M M is the doffer knife or comb; G, the carded fleece hemmed
in by the funnel _a_, pressed between the rollers _b_, and then falling
in narrow fillets into its can. _Fig._ 327. K L are the feed rollers; A
B, the card drum; C D, the tops; E F, the doffer card; M N, the doffer
knife; _d_, _b_, _c_, the card-end passing between compressing rollers
into the can _a_.
_The drawing and doubling_ are the next operation. The ends, as they
come from the cards, are exceedingly tender and loose, but the filaments
of the cotton are not as yet laid so parallel with each other as they
need to be for machine spinning. Before any degree of torsion therefore
be communicated, a previous process is required to give the filaments a
level arrangement in the ribands. The drawing out and doubling
accomplish this purpose, and in a manner equally simple and certain. The
means employed are drawing-rollers, whose construction must here be
fully explained, as it is employed in all the following machines; one
example of their use occurred, indeed, in treating of the cards.
[Illustration: 328]
Let _a_ and _b_, _fig._ 328., represent the section of two rollers lying
over each other, which touch with a regulated pressure, and turn in
contact upon their axes, in the direction shown by the arrows. These
rollers will lay hold of the fleecy riband presented to them at _a_,
draw it through between them, and deliver it quite unchanged. The length
of the piece passed through in a given time will be equal to the space
which a point upon the circumference of the roller would have percured
in the same time; that is, equal to the periphery of one of the rollers
multiplied by the number of its entire revolutions. The same thing holds
with regard to the transmission of the riband through between a second
pair of rollers, _c_, _d_, and a third, _e_, _f_. Thus the said riband
issues from the third pair exactly the same as it entered at _a_,
provided the surface speed of all the rollers be the same. But if the
surface speed of _c_ and _d_ be greater than that of _a_ and _b_, then
the first-named pair will deliver a greater length of riband than the
last receives and transmits to it. The consequence can be nothing else
in these circumstances than a regulated drawing or elongation of the
riband in the interval betwixt _a_, _b_, and _c_, _d_, and a
condensation of the filaments as they glide over each other, to assume a
straight parallel direction. In like manner the drawing may be repeated
by giving the rollers, _e_, _f_, a greater surface speed than that of
the rollers, _c_ and _d_. This increase of velocity may be produced,
either by enlarging the diameter, or by increasing the number of turns
in the same time, or finally by both methods conjoined. In general the
drawing-machine is so adjusted, that the chief elongation takes place
between the second and third pairs of rollers, while that between the
first and second is but slight and preparatory. It is obvious, besides,
that the speed of the middle pair of rollers can have no influence upon
the amount of the extension, provided the speed of the first and third
pair remains unchanged. The rollers, _a_, _b_, and _c_, _d_, maintain
towards each other continually the same position, but they may be
removed with their frame-work, more or less, from the third pair, _e_,
_f_, according as the length of the cotton staple may require. The
distance of the middle point from _b_ and _d_, or its line of contact
with the upper roller, is, once for all, so calculated, that it shall
exceed the length of the cotton filaments, and thereby that these
filaments are never in danger of being torn asunder by the second pair
pulling them while the first holds them fast. Between _d_ and _f_, where
the greatest extension takes place, the distance must be as small as it
can be without risk of tearing them in that way; for thus will the
uniformity of the drawing be promoted. If the distance between _d_ and
_f_ be very great, a riband passing through will become thinner, or
perhaps break in the middle; whence we see that the drawing is more
equable, the shorter is the portion submitted to extension at a time,
and the nearer the rollers are to each other, supposing them always
distant enough not to tear the staple.
The under rollers _b d f_ are made of iron, and, to enable them to lay
firmer hold of the filaments, their surfaces are fluted with triangular
channels parallel to their axes. The upper rollers, _a c e_, are also
made of iron, but they are smooth, and covered with a double coating,
which gives them a certain degree of softness and elasticity. A coat of
flannel is first applied by sewing or gluing the ends, and then a coat
of leather in the same way. The junction edges of the leather are cut
slanting, so that when joined by the glue (made of isinglass dissolved
in ale) the surface of the roller may be smoothly cylindrical. The top
rollers are sometimes called the _pressers_, because they press by means
of weights upon the under ones. These weights are suspended to the
slight rods _k k´_; of which the former operates on the roller _e_
alone, the latter on the two rollers _a_ and _e_ together. For this
purpose the former is hung to a C shaped curve _i_, whose upper hook
embraces the roller _e_; the latter to a brass saddle _h_, which rests
upon _a_ and _c_. A bar of hard wood, _g_, whose under surface is
covered with flannel, rests, with merely its own weight, upon the top
rollers, and strips off all the loose hanging filaments. Similar bars
with the same view are made to bear up under the fluted rollers _b d f_,
and press against them by a weight acting through a cord passing over a
pulley. Instead of the upper dust-covers, light wooden rollers covered
with flannel are occasionally applied.
Were the drawing of a riband continued till all its fibres acquired the
desired degree of parallelism, it would be apt, from excessive
attenuation, to tear across, and thereby to defeat the purpose of the
spinner. This dilemma is got rid of in a very simple way, namely, by
laying several ribands together at every repetition of the process, and
incorporating them by the pressure of the rollers. This practice is
called _doubling_. It is an exact imitation of what takes place when we
draw a tuft of cotton wool between our fingers and thumb in order to
ascertain the length of the staple, and replace the drawn filaments over
each other, and thus draw them forth again and again, till they are all
parallel and of nearly equal length. The doubling has another advantage,
that of causing the inequalities of thickness in the ribands to
disappear, by applying their thicker to their thinner portions, and
thereby producing uniformity of substance.
[Illustration: 329 330]
The drawing frame, as shown in section in _figs._ 328. 330., and in a
back view in _fig._ 329., will require, after the above details, little
further explanation. _l l_ are the weights which press down the top
rollers upon the under ones, by means of the rods _k k´_ and hook _i_.
Each fluted roller is, as shown at _f_, _fig._ 329., provided in the
middle of its length with a thinner smooth part called the _neck_,
whereby it is really divided into two fluted portions, represented by _e
e_ in the figure. Upon this middle neck in the pressure rollers, the
hook _i_ and the saddle _h_ immediately bear, as shown in the former
_fig._ 328. The card-ends, to the number probably of six, are introduced
to the drawing frame either from tin cans, placed at _e e_, _fig._ 330.,
and at A, _fig._ 329., or from lap-bobbins; and, after passing through
it, the ribands or slivers are received either into similar tin cans, as
_g_, or upon other lap-bobbins upon the other side. These appendages may
be readily conceived, and are therefore not exhibited in all the
drawings. Three of the slivers being laid together, are again introduced
to the one fluted portion _a b_, _fig._ 328., and three other slivers to
the other portion. The sloping curved tin or brass plate _s_, _fig._
329., with its guide pins _t_, serves to conduct the slivers to the
rollers. When the two threefold slivers have passed through between the
three pairs of rollers, and been thereby properly drawn, they run
towards each other in an oblique direction, behind the last roller pair
_e f_, _fig._ 328., and unite, on issuing through the conical funnel
_m_, _fig._ 329., into a single riband or spongy sliver; which is
immediately carried off with equable velocity by two smooth cast-iron
rollers, _n o_, _fig._ 329. and 330. and either dropped into a can, or
wound upon a large bobbin. The surface speed of these rollers is made a
trifle greater than that of the delivery drawing rollers, in order to
keep the portion of sliver between them always in an extended state.
Four fluted drawing portions are usually mounted in one drawing frame,
which are set a-going or at rest together. To save all unnecessary
carrying of the cans from the back to the front of the frame, the
drawing heads are so placed, that the first and third, discharge their
slivers at the one side, and the second and fourth at the other. By this
arrangement, the cans filled behind one head, are directly pushed aside
in front of the next drawing head; by which alternate distribution the
work goes on without interruption.
The _fast_ pulley _u_, _fig._ 330., by which the whole machine is
driven, derives its motion from the main shaft of the mill by means of
the band _w_. The similar pulley _x_, which sits loose upon the axis,
and turns independently of it, is called the loose pulley; both together
being technically styled _riggers_. When the operative desires to stop
the machine, he transfers the band from the fast to the loose pulley by
means of a lever, bearing a fork at its end, which embraces the band.
Upon _y_, four pulleys such as _x_ are fixed, each of which sets in
motion a drawing head, by means of a band like _w_ going round the
pulleys _x_ and _u_. On account of the inverted position of the heads,
which requires the motion of _u_ to be inverted, the bands of the first
and third heads are open, but those of the second and fourth are
crossed. Every head is provided with a loose pulley _v_, as well as the
fast pulley _u_, in order to make the one stop or move without affecting
the others. The shaft of the pulley _u_ is the prolonged shaft of the
backmost fluted roller _f_. It carries besides a small pulley _q_,
which, by means of the band _r_, and the pulley _p_, _fig._ 329., sets
in motion the undermost condensing roller _o_. The upper roller _n_,
presses with its whole weight upon it, and therefore turns by friction.
The toothed wheel-work, by which the motions are communicated from the
backmost fluted roller to the middle and front ones, are seen in _fig._
330.
The wheel _f_, _fig._ 328., of 20 teeth, works in a 44-toothed
carrier-wheel, on whose axis there are two smaller wheels; 2 with 26
teeth, and 1 with 22 teeth. The wheel _d_, _fig._ 330., of the middle
roller, and the wheel _b_ of the front roller, are set in motion by
other carrier wheels; the first has 27 teeth, and the last 40. For every
revolution of _b_, the roller _d_ makes nearly 1-3/4 turns, and the
roller _f_, 4 revolutions. The top rollers revolve, as we have stated,
simply by the friction of contact with the lower ones. Now suppose the
diameter of the rollers _b_ and _d_ to be 1 inch or 12 lines, that of
_f_, 1-1/4 inches or 15 lines, the surface velocities of the three pairs
of rollers in the series will be as 1, 1-3/4, and 5. Every inch of the
cotton sliver will be therefore extended between the first and second
pair of rollers into 1-3/4 inches, and between the second and third or
delivery pair into 5 inches; and after the sliver has passed through all
the four drawing heads, its length will be increased 625 times = 5 × 5 ×
5 × 5.
The further the drawing process is pushed, the more perfectly will its
object be accomplished; namely the parallelism of the filaments. The
fineness of the appearance of the sliver after the last draught depends
upon the number of doublings conjointly with the original fineness and
number of drawings. The degree of extension may be increased or
diminished, by changing the wheels in _fig._ 330., for others with a
different number of teeth. Thus the grist or fineness of the sliver may
be modified in any desired degree; for, when the subsequent processes of
the mill remain the same, the finer the drawings the finer will be the
yarn. For spinning coarse numbers or low counts, for example, six
card-ends are usually transmitted through the first drawing head, and
converted into one riband. Six such ribands again form one in the second
draught; six of these again go together into the third sliver; and this
sliver passes five-fold through the last draught. By this combination
1080 of the original card-ends are united in the finished drawn sliver =
6 × 6 × 6 × 5. The fineness of the sliver is, however, in consequence of
these doublings not increased but rather diminished. For, by the
drawing, the card-end has been made 625 times longer, and so much
smaller; by the doubling alone it would have become 1080 times thicker;
therefore the original grist is to the present as 1, to the fraction
625/1080; that is, supposing 1072 feet of the riband delivered by the
card to weigh one pound, 625 feet, the sliver of the last drawing, will
also weigh a pound, which corresponds in fineness to number 0·24, or
nearly 1/4.
The rearmost or last drawing roller has a circumference of nearly 4
inches, and makes about 150 revolutions per minute; hence, each of these
drawing heads may turn off 35,000 feet of sliver in 12 hours.
Some manufacturers have lately introduced a double roller beam, and a
double draught at the same doubling, into their drawing frames. I have
seen this contrivance working satisfactorily in mills where low counts
were spun, and where the tube roving frame was employed; but I was
informed by competent judges, that it was not advisable where a level
yarn was required for good printing calicoes.
The loss which the cotton suffers in the drawing frame is quite
inconsiderable. It consists of those filaments which remain upon the
drawing rollers, and collect, in a great measure, upon the flannel
facing of the top and bottom cleaner bars. It is thrown among the top
cleanings of the carding engine. When from some defect in the rollers,
or negligence in piecing the running slivers, remarkably irregular
portions occur in the ribands, these must be torn off, and returned to
the lap machine to be carded anew.
The fifth operation may be called the _first spinning process_, as in
it, the cotton sliver receives a twist; whether the twist be permanent
as in the bobbin and fly frame, or be undone immediately, as in the
tube-roving machine. In fact, the elongated slivers of parallel
filaments could bear little further extension without breaking asunder,
unless the precaution were taken to condense the filaments by a slight
convolution, and at the same time to entwine them together. The twisting
should positively go no further than to fulfil the purpose of giving
cohesion, otherwise it would place an obstacle in the way of the future
attenuation into level thread. The combination of drawing and twisting
is what mainly characterizes the spinning processes, and with this fifth
operation therefore commences the formation of yarn. As however a sudden
extension to the wished-for fineness is not practicable, the draught is
thrice repeated in machine spinning, and after each draught a new
portion of torsion is given to the yarn, till at last it possesses the
degree of fineness and twist proportioned to its use.
The preliminary spinning process is called _roving_. At first the
torsion is slight in proportion to the extension, since the solidity of
the still coarse sliver needs that cohesive aid only in a small degree,
and looseness of texture must be maintained to facilitate to the utmost
the further elongation.
[Illustration: 331]
_Fig._ 331. is a section of the can roving frame, the ingenious
invention of Arkwright, which till within these 14 years was the
principal machine for communicating the incipient torsion to the spongy
cord furnished by the drawing heads. It differs from that frame in
nothing but the twisting mechanism; and consists of two pairs of drawing
rollers, _a_ and _b_, between which the sliver is extended in the usual
way; _c_ are brushes for cleaning the rollers; and _d_ is the weight
which presses the upper set upon the lower. The wiping covers (not shown
here) rest upon _a b_. The surface speed of the posterior or second pair
of rollers is 3, 4, or 5 times greater than that of the front or
receiving pair, according to the desired degree of attenuation. Two
drawn slivers were generally united into one by this machine, as is
shown in the figure, where they are seen coming from the two cans _e e_,
to be brought together by the pressure rollers, before they reach the
drawing rollers _a b_. The sliver, as it escapes from these rollers, is
conducted into the revolving conical lantern _g_, through the funnel _f_
at its top. This lantern-can receives its motion by means of a cord
passing over a pulley _k_, placed a little way above the step on which
it turns. The motion is steadied by the collet of the funnel _f_, being
embraced by a brass busk. Such a machine generally contained four
drawing heads, each mounted with two lanterns; in whose side there was a
door for taking out the conical coil of roving.
The motion imparted to the back roller by the band pulley or rigger _m_,
was conveyed to the front one by toothed wheel work.
The vertical guide pulley at bottom _n_, served to lead the driving band
descending from the top of the frame round the horizontal whorl or
pulley upon the under end of the lantern. The operation of this
can-frame was pleasing to behold; as the centrifugal force served both
to distribute the soft cord in a regular coil, and also to condense a
great deal of it most gently within a moderate space. Whenever the
lantern was filled, the tenter carried the roving to a simple machine,
where it was wound upon bobbins by hand. Notwithstanding every care in
this transfer, the delicate texture was very apt to be seriously
injured, so as to cause corresponding injuries in every subsequent
operation, and in the finished yarn. Messrs. Cocker and Higgins, of
Salford, had the singular merit, as I have said, of superseding that
beautiful but defective mechanism, which had held a prominent place in
all cotton mills from almost the infancy of the factory system, by the
following apparatus.
_The Bobbin and Fly frame_ is now the great roving machine of the cotton
manufacture; to which may be added, for coarse spinning, the tube
roving frame. Of such a complicated machine as the bobbin and fly frame,
it is not possible to give an adequately detailed description in the
space due to the subject in this Dictionary. Its mechanical combinations
are however so admirable as to require such an account as will make its
functions intelligible by the general reader.
[Illustration: 332]
_Fig._ 332. exhibits a back view of this machine; and _fig._ 333. a
section of some of the parts not very visible in the former figure. The
back of the machine is the side at which the cotton is introduced
between the drawing rollers.
[Illustration: 333]
The cans, or lap-bobbins filled with slivers at the drawing frame, are
placed in the situation marked B, _fig._ 333., in rows parallel with the
length of the machine. The sliver of each can or the united slivers of
two contiguous cans are conducted upwards along the surface of a sloping
board _f_, and through an iron staple or guide _e_, betwixt the usual
triple pair of drawing rollers, the first of which is indicated by _a_,
_b_. In _fig._ 332., for the purpose of simplifying the figure, the
greater part of these rollers and their subordinate parts are omitted.
After the slivers have been sufficiently extended and attenuated between
the rollers, they proceed forwards, towards the spindles _i i i_, where
they receive the twist, and are wound upon the bobbins _h_. The machine
delineated contains thirty spindles, but many bobbin and fly frames
contain double or even four times that number. Only a few of the
spindles are shown in _fig._ 332., for fear of confusing the drawing.
[Illustration: 334]
With regard to the drawing functions of this machine, I have already
given abundant explanation, so far as the properties and operation of
the rollers are concerned. The frame-work of this part of the machine,
called the _roller-beam_, is a cast iron bench, upon which nine bearers
_c_, are mounted for carrying the rollers. The fluted rollers _a a a_,
_fig._ 334., are constructed in four pieces for the whole length, which
are parted from each other by thinner smooth cylindric portions _z_,
called necks. Seven such partings for four rollers, and one parting for
two rollers, constitute together the 30 fluted rollers of which the
whole series consists. The coupling of these roller subdivisions into
one cylinder, is secured by the square holes _x_, and square pins _y_,
_fig._ 334., which fit into the holes of the adjoining subdivision. The
top or pressure rollers _b_, are two-fold over the whole set; and the
weighted saddle presses upon the neck _w_, which connects every pair, as
was already explained under _fig._ 329. These weights _g_, _g_, _fig._
333., are applied in this as in the _drawing frame_; _d_, are the bars
faced with flannel for cleaning the top rollers. A similar bar is
applied beneath the rollers, to keep the flutings clean.
[Illustration: 335]
The structure and operation of the spindles _i_, may be best understood
by examining the section _fig._ 335. They are made of iron, are
cylindrical from the top down to _a_², but from this part down to the
steel tipt rounded points they are conical. Upon this conical portion
there is a pulley _k_, furnished with two grooves in its circumference,
in which the cord runs that causes the spindle to revolve. The wooden
bobbin _h_, is slid upon the cylindrical part, which must move freely
upon it, as will be presently explained. To the bobbin another
two-grooved pulley or whorl _q_ is made fast by means of a pin _r_,
which passes through it; by removing this pin, the bobbin can be
instantly taken off the spindle. The upper end of the spindle bears a
fork _s t_, which may be taken off at pleasure by means of its
left-handed screw; this fork or flyer, has a funnel-formed hole at _v_.
One arm of the fork is a tube _s_, _u_, open at top and bottom; the leg
_t_, is added merely as a counterpoise to the other. In _fig._ 333., for
the sake of clearness, the forks or flyers of the two spindles here
represented are left out; and in _fig._ 332. only one is portrayed for
the same reason. It is likewise manifest from a comparison of these two
figures that the spindles are alternately placed in two rows, so that
each spindle of the back range stands opposite the interval between two
in the front range. The object of this distribution is economy of space,
as the machine would need to be greatly longer if the spindles stood all
in one line. If we suppose the spindles and the bobbins (both of which
have independent motions) to revolve simultaneously and in the same
direction, their operation will be as follows: The sliver properly drawn
by the fluted rollers, enters the opening of the funnel _v_, proceeds
thence downwards through the hole in the arm of the fork, runs along its
tube _u_, _s_, and then winds round the bobbin. This path is marked in
_fig._ 335. by a dotted line.
The revolution of the spindles in the above circumstances effects the
twisting of the sliver into a soft cord; and the flyer _s_, _t_, or
particularly its tubular arm _s_, lays this cord upon the bobbin. Were
the speed of the bobbins equal to that of the spindles, that is, did the
bobbin and spindle make the same number of turns in the same time, the
process would be limited to mere twisting. But the bobbin anticipates
the flyers a little, that is, it makes in a given time a somewhat
greater number of revolutions than the spindle, and thereby effects the
continuous winding of the cord upon itself. Suppose the bobbin to make
40 revolutions, while the spindle completes only 30; 30 of these
revolutions of the bobbin will be inoperative towards the winding-on,
because the flyers follow at that rate, so that the cord or twisted
sliver will only be coiled 10 times round the bobbin, and the result as
to the winding-on will be the same as if the spindle had stood still,
and the bobbin had made 40 - 30 = 10 turns. The 30 turns of the spindles
serve, therefore, merely the purpose of communicating twist.
The mounting and operation of the spindles are obviously the same as
they are upon the household flax wheel. In the bobbin and fly frame
there are some circumstances which render the construction and the
winding-on somewhat difficult, and the mechanism not a little
complicated. It may be remarked in the first place, that as the cord is
wound on, the diameter of the bobbin increases very rapidly, and
therefore every turn made round it causes a greater length of roving to
be taken up in succession. Were the motions of the bobbins to continue
unchanged in this predicament, the increased velocity of the winding-on
would require an increased degree of extension, or it would occasion
the rupture of the cord, because the front fluted rollers move with
uniform speed, and therefore deliver always the same length of sliver in
the same time. It is therefore necessary to diminish the velocity of the
bobbins, or the number of their turns, in the same proportion as their
diameter increases, in order that the primary velocity may remain
unchanged. Moreover, it is requisite for the proper distribution of the
cord upon the bobbin, and the regular increase of its diameter, that two
of its successive convolutions should not be applied over each other,
but that they should be laid close side by side. This object is attained
by the up and down sliding motion of the bobbin upon the spindle, to the
same extent as the length of the bobbin barrel. This up and down motion
must become progressively slower, since it increases the diameter of the
bobbin at each range, by a quantity equal to the diameter of the sliver.
What has now been stated generally, will become more intelligible by an
example.
Let it be assumed that the drawing rollers deliver, in 10 seconds, 45
inches of roving, and that this length receives 30 twists. The spindles
must, in consequence, make 30 revolutions in 10 seconds, and the bobbins
must turn with such speed, that they wind up the 45 inches in 10
seconds. The diameter of the bobbin barrels being 1-1/2 inches, their
circumference of course 4-1/2 inches, they must make 10 revolutions more
in the same time than the spindles. The effective speed of the bobbins
will be thus 30 + 10 = 40 turns in 10 seconds. Should the bobbins
increase to 3 inches diameter, by the winding-on of the sliver, they
will take up 9 inches at each turn, and consequently 45 inches in 5
turns. Their speed should therefore be reduced to 30 + 5 = 35 turns in
10 seconds. In general, the excess in number of revolutions, which the
bobbins must make over the spindles, is inversely as the diameter of the
bobbins. The speed of the bobbins must remain uniform during the period
of one ascent or descent upon the spindle, and must diminish at the
instant of changing the direction of their up and down motion; because a
fresh range of convolutions then begins with a greater diameter. When,
for example, 30 coils of the sliver or roove are laid in one length of
the bobbin barrel, the bobbin must complete its vertical movement up or
down, within 30 seconds in the first case above mentioned, and within 60
seconds in the second case.
The motions of the drawing rollers, the spindles, and bobbins, are
produced in the following manner:--A shaft _c´_, _fig._ 332. and 333.,
extending the whole length of the machine, and mounted with a fly wheel
_d´_, is set in motion by a band from the running pulley upon the shaft
of the mill, which actuates the pulley _a´_. _b´_ is the loose pulley
upon which the band is shifted when the machine is set at rest. Within
the pulley _a´_, but on the outside of the frame, the shaft _c´_ carries
a toothed wheel _b_² with 50 teeth, which by means of the intermediate
wheel _c_² turns the wheel _d_² upon the prolonged shaft of the backmost
fluted roller (_m_², _fig._ 333.) This wheel _d_² has usually 54 teeth;
but it may be changed when the roove is to receive more or less twist;
for as the spindles revolve with uniform velocity, they communicate the
more torsion the less length of sliver is delivered by the rollers in a
given time. Upon the same shaft with _d_², a pinion _e_² of 32 teeth is
fixed, which works in a wheel _f_² of 72 teeth. Within the frame a
change pinion _g_² is made fast to the shaft of _f_². This pinion, which
has usually from 24 to 28 teeth, regulates the drawing, and thereby the
fineness or number of the roving. It works in a 48-toothed wheel _h_²
upon the end of the backmost fluted roller _a_, _fig._ 333. The other
extremity of the same roller, or, properly speaking, line of rollers,
carries a pinion _l_², furnished with 26 teeth, which, by means of the
broad intermediate wheel _k_², sets in motion the pinion _i´_² of 22
teeth upon the middle roller. When the diameter of all the drawing
rollers is the same, suppose 1 inch, their proportional velocities will
be, with the above number of teeth in the wheel work, if _g_² have 24
teeth, as 1 : 1·18 : 4·5; and the drawn sliver will have 4-1/2 times its
original length. The front or delivery roller of the drawing frame is of
late years usually made 1-1/4 or 1-3/8 inches in diameter. If 625 feet
of the sliver from the drawing frame weighed one pound, 2790 feet of the
roving will now go to this weight, and the number will be 1·12; that is,
1 hank and 12 hundredths to the pound. The front pair of fluted rollers
makes about 90 revolutions, and delivers 282·6 inches of roving in the
minute, when of one inch diameter.