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.
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.
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.