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Carding is an operation in which fibres like cotton and wool are subjected to the action of surfaces having closely set wire points. This action loosens and partially disentangles the fibres from each other and may be said to be the final stage of the opening out or loosening processes, so that if required the fibres may be readily straightened and arranged in roughly parallel order in the subsequent processes. It was and still is probably the most important of the preliminary processes of spinning. The early inventors of the spinning machines found that carding machines were needed.
Before the introduction
of these machines, carding was for centuries carried out by means of hand
cards. The lower card was held resting on the knee (the process was
sometimes called knee carding), the cotton or wool was placed on the teeth,
and the upper card moved in the direction shown in A below. Owing
to the inclination of the wires, which were usually set in leather, each
surface held some of the fibres, and separation and disentanglement resulted.
By turning one of the cards round, as shown in B below, the lower card
was not 'stripped' of its fibres, and results being a thin film or web
of carded fibres.
Carding was
the first cotton process to be mechanized. After
cotton is picked, the usual process is to card it; first, by a carding
machine, called a breaker; and a second time on another, called a
finisher. The breaker consists of a larger and smaller cylinder.
The larger or main cylinder, is covered with sheet cards, and moves at
a considerable velocity; the lesser, or doffing cylinder is covered with
a spiral fillet of card, wound round it and moves slowly. These cylinders
revolve in opposite directions, and nearly in contact with each other.
Over the main cylinder, is a kind of arch, covered with cards, at rest,
called the top-cards. The cotton is fed by means of rollers into
the main cylinder. The main cylinder lays it on the doffing cylinder,
from which it is combed, and in an uniform fleece is wound round a cylinder,
or sometimes instead of it, on a perpetual cloth. After this cylinder
or cloth has been a certain number of revolutions, and thereby plying or
doubling the cotton is broken off, and is in that state, called a lap,
ready to be carried to the finisher. The finisher is similar to the
breaker, only that the fleece, instead of forming a lap, is gradually brought
into a narrow band or sliver, and is compressed by a pair of rollers, which
deliver it into a tin can, which is afterwards removed to the drawing frame.
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In this machine, drawing
first occurs. Drawing is the ground-work or principle of Arkwright's
patent, for it is used in the roving and spinning, as well as in the drawing
frame. It is an imitation of what is done by the finger and thumb,
in spinning by hand, and is performed by means of two pairs of rollers.
The upper roller of the first pair is covered by leather, which being an
elastic substance, is pressed, by means of a spring or weight. The
lower roller, made of metal, is fluted, in order to keep a firm hold of
the fibres of the cotton. Another simple pair of rollers are placed
near to those we have been describing. The second pair moving at
a greater velocity, pull the fibres of the cotton from the first pair of
rollers. If the surface of the last pair move at twice or thrice
the velocity of the first pair, the cotton will be drawn twice or thrice
finer than it was. Several of the narrow ribands or slivers from
the cards by being passed through a system or rollers, the reduced ribands
are united into one sliver. These operations of drawing and plying
serve to equalize the body of cotton and to bring its fibres more on end,
which, in the card-ends, were crossed in all directions. These slivers
are again combined and drawn out, so that one sliver of the finisher's
drawing contains many plies of card-ends. The cotton is received
into moveable tin cans similar to those used for receiving the cotton from
the cards.
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The roving is a process similar to the drawing, only that it always communicates a degree of twist to the cotton. The roves are wound up on bobbins, and are then ready to be spun. The operation of winding is in some cases performed by hand, and in others by power. The bobbins containing the rove are placed on the back part of the spinning frame. The spinning is little more than a repetition of the process gone through in the making of rovings. The spinning frame contains rollers similar to those of the drawing and roving frames, which serve to extend the rove, and reduce it to the required fineness; at the same time it is twisted by means of a spindle, but of a different kind from that of the common jenny.
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