Cards, in cloth manufacture, combs of a peculiar construction, which serve to disengage the fibres of an entangled mass and lay them parallel. Every fibre on the card is doubled up, and they are afterward extended by an operation called drawing and doubling. Cards are made by inserting in a piece of leather fine wires projecting about a quarter of an inch from the leather, and all slightly bent the same way. These small hooks are prevented from turning by being made in pairs. Two of them are made of a piece of wire bent like the three sides of a square; this is inserted through two holes in the leather, and the two projecting ends are bent in the same direction. The leather, bristling with hooks, is attached to a flat or cylindrical surface. A card is an instrument in which two such surfaces are opposed, and made to move at a very small distance from each other; the cotton or wool to be disentangled is placed between them. The cards opposed to each other are placed in different positions according to the result to be obtained. At first the hooks are placed in opposite directions, so that at each stroke some of the fibres of the tuft are hooked on one card and some on the other; this is called the tearing position.
After all the fibres are hooked on, one of the cards is reversed, and at the next stroke the card which moves in the direction pointed out by its own hooks strips from the other all the fibres; this is called the stripping position. Flat cards have been used by hand in the manner just described. Cylinder cards and the carding machine were invented in the 18th century by Lewis Paul of Northampton, England, and were much improved by Sir Richard Arkwright. This machine operates as follows: The wool or cotton to be carded, after being arranged in the shape of a sheet in another machine, is engaged between the feed rollers. The fibres are taken off by the drum and carried to the large runner, which takes off the loose fibres, and is stripped of them by the small roller, which returns them to the drum. The drum carries them anew to the large runner, but they are hooked more firmly and move onward to the top cards; some of them remain there, and the others are completely extended and reach the doffer, which takes off a portion of them; these are stripped from it by the doffer knife and form the fleece; the others are carried round again to the runners and top cards. At each passage some are taken off.
From time to time the top cards and cylinders are cleaned of the fibres accumulated in their teeth. - The machine for making cards was the invention of Amos Whittemore, of Cambridge, Mass., for which he took a patent in 1797. An English patent was issued in 1811 to J. C. Dyer. A fillet of leather is prepared of equal thickness throughout by drawing it between a cylinder and a scraper, which takes off all inequalities. One end of the fillet is then placed between two feed cylinders, and is guided laterally by rollers. These are acted upon at intervals, and each time they move they carry the fillet sideways the distance between two hooks. When it is necessary to place the hooks in oblique lines, the motion described is combined with a motion of the feed rollers. After each motion of the fillet of leather, a fork brought down at the proper angle pierces two holes in the leather; a piece of a hard-drawn steel wire is fed in; a small block of steel descending upon it holds it firmly; the wire is cut off; two sliding pieces of metal bend it up against the sides of the block, and the points are pressed into the holes in the leather. The blocks and other parts spoken of recede out of the way, and other parts come forward to drive the staple in and bend it to the required angle.
All these operations are effected by means of rotary cams acting upon the ends of levers or of rods, some by their periphery, some by their sides, as is usual in machines for manufacturing small objects which require to be submitted to numerous and complex motions. - Numerous patents have been granted by the United States for improvements in cards, carding machines, and card making. (See Cotton Manufacture).