The process is as follows :—The machine having been supplied with the lap G, the end of which ia pasaed under the feed-roller C, the lap-roller G' alowly revolve.s, unrolling the web from the lap. The " licker-in " B, running at a autface speed of about 800 ft. a minute, atrikes the cotton in a downward direction from the feed-roller, combing the fibres straight, and carrying them to the cylinder A, which, revolving at a surface rate of about 1600 ft. a minute, owing to its greater apeed, and to the cards being bent in the direction of ita motion—upward. strips all the cotton from the former, at that portion of its periphery nearest the licker-in. The cylinder carries the cotton forward to the first roller, which usually is a cleansing roller, end is technically called the " dirt roller." Ite surface speed is comparatively slow, only about 15 ft. a minute. Its function is to gather from the cotton all the remaining dirt, motes, seed, leaf, and naps, and to aid in combing the fibrea atraight. The dirt extracted is carried round, and stripped from the roller by the attendant ; sometimes, however, a vihrating comb ia attached for that purpoae. The main cylinder carries the cotton onward to the rollers r and s, which succeasively assiat in perfecting the cleansing and combing of the cotton. These rollers being set in opposition to the main cylinder, their contact surfaces move in the same direction, but at a greatly reduced speed. The cards aro set on the stripper with the teeth inclined in the direction of the motion, whilst those on the workers are disposed in the reverse way, the teeth being thus in opposition to those of the main cylinder. The latter carries the cotton paat the atripper to the worker r, the teeth of which exert a combing action, owing to its relatively alow movement of about 20 ft. a minute. That portion of the cotton, which is taken up by the teeth of the worker r, is carried round, until, coming into contact with the stripper s, it is taken by the latter, which moves at a surface velocity of 400 ft. a minute, and ia itself stripped by the more swiftly revolving main cylinder. After passing the seriea of workera and strippers, the cotton is taken from the main cylinder by the doffing cylinder D, which has its teeth arranged in the opposite way, but moves only at the slow mte of about 60-70 ft. a minute in the same direction. The cotton is carried round its under side, until brought within reach of the doffer-comb t, fitted upon vibrating arms, and stretching across the face of the doffer, from which it strips the cotton in a thin film. Its movement is vertical, or nearly so ; it strips the doffer in its descent, and clears itself when ascending. It makes 600-1000 strokes a minute according to requirement, being driven hy balanced cranks. From the doffer-comh, the cotton is delivered in a thin sheet or film, which is condensed in its passage through a trumpet-shaped tube, and com pression rollers c, whence it is carried over the pillar E, and, by an ingenious motion, is coiled iu the can F, which stands upon a revolving plate. The cotton thus becomes a " sliver." This form of carding-engine is probably most extensively in use, being best adapted for low and medium numbers of yarn. It is simple, easily set, and not liable to get out of order. The produc tion exceeds that from flats, or the Wellman card, hut the quality of the work is hardly equal. The cards should be put on both cylinders and rollers, closely, evenly, and with uniforin tension. After being securely fastened, all should be evenly ground. The framo of the machine ought to be perfectly level, and placed on a floor free from vibration. The doffer, the taker-in, and the rollers, should he set exactly parallel with the cylinder, and he carefully adjusted as close as possible without touching.
Another system of carding is the one in which the rollers and strippers of the machine described above are dispensed with, the substitutes being a series of flats, extending from side to side of the machine, and covering the upper half of the cylinder. The under sides of these flats are covered with cards, and are so adjusted as to effect the same object as the above. This form of carding engine has passed through numerous mutations and improvements, before its present stage of perfection was attained. Formerly the fiats were stripped by hand, which required steady atten tion and skill on the part of the operative ; qualities which were not always found in combination. As the difficulty of obtaining a supply of efficient men increased, attempts were made, with varying degrees of success, to accomplish the work by mechanical appliances. Amongst the most successful of these, was the method devised by George Wellman, an American, who invented the machine so widely known as the " Wellman card." On its introduction into this country, it was taken in hand by Dobson and Barlow, machinists, further improved in numerous details, and adapted to work as either a first or " breaker," or as a finisher card. In the production of medium numbers of yarns, more carding is necessary than for lower counts. In many cases, the roller card is used as a " breaker" ; in others, various adaptations compoimded of the roller and the flat card are used, and sometimes modifications of the latter alone.
The finisher carding-engine on the Wellman principle, as made by- Dobson and Barlow, is represented in the accompanying illustration, Fig. 536. In its main parts, it differs little from the preceding. The series of flats f are fitted upon adjustable brackets g, which are so arranged as to admit of each flat being set accurately parallel to the face of tbe cylinder. The lever or arm h moves backwards and forwards over the. semicircle of flats f; on this arm, is fitted the flat-lifting and stripping apparatus, which has proved to be such au ingenious substitute for human attention. By means of this arrangement, the fiats are lifted from their respective brackets, and turned upward, and thtir face is exposed to the action of the stripper roller, which clears away the accumulated waste that has gathered thereon. Immediately this has been done, the mechanism restores it to
its place ; the arm resumes its movement, until it reaches the next flat that has to be stripped, when it again pauses, to allow the above performance to be repeated, and so continues until the whole of the flats are stripped, when the operations recommence. The order in which the flats are lifted varies, those nearest the lap needing to be stripped most often. The numbers of fiats are so arranged that, whichever plan be adopted, each in proper order will come under the action of the stripper. The brackets e are for the reception of the grinding roller, for grinding the cylinder and doffer, without removing them from their positions.
The revolving flat card is another form of the same machine. In this machine, Fig. 537, the flats are arranged in the form of an endless lattice ; the working flats rest upon a semicircular guide n, upon the tops of the sides of the frame, adjusted by means of the screws p, Those out of action are suspended upon carrier rollers g, over which they travel. The rate at which the lattice moves is very slow—about 1 in. a minute. In their course, each flat is subjected to the action of the stripping roller h, after which it passes on to take its place amongst the working flats.
Besides these principal forms of the carding-engine, there are several modifications, wherein the distinctive features of the roller and the Wellman card are combined. These are called " combination " or " union " cards.
The most remarkable machine employed in the preparation of cotton for spinning is the combing machine used for long-stapled cottons, for fine yams. It was invented by II. Hellmann, of Mulhausen, and first became extensively known to the public through being shown at the Exhibition in London in 1851. The patent was purchased by a company of Manchester spinneri of fine yarns, for the sum of 30,0001. They for a time restricted its use to them selves, but subsequently permitted it to be supplied to the public, on payment of a royalty of 300/., which brought its cost to 500/. This was reduced, as the patent neared its expiration. It was, however, virtually extended by the patenting of improvements which experience had suggested. It has since been extensively adopted, and, for making the best classes of yarns, is now regarded as indispensable. Another combing machine, invented by Imbs, has since been favourably received. In the Hellmann " comber " (Fig. 538), the lap a is placed upon the rollers b, which, by their revo lution, unwind the fleeceiand pass it down an inclined guide c to a pair of steel feed-rollers dd'; the nether one is fluted, and the upper is covered with leather. These rollers have an intermittent motion, obtained through peculiar gearing, by which they are turned of a revolution at a time. They deliver the,cotton to a nipper, which opens to allow its passage. This nipper is com posed of two parts—the blade e and the cushion el, the latter being covered with leather. The nipper-blade receives motion from a cam, at the gearing end of the machine. The motion is transmitted through two levers, a connecting-rod es, and a shaft. The movement imparted to the blade is greater than is required to bring it into contact with the cushion plate, and thc latter, being hung upon a pivot, and held forward by a spring, is pushed backward by the pros sure of the blade, into a position which subjects the cotton to the action of the combing cylinder. A reverse movement then oecurs, which permits the cushion plate and nipper-blade to advance with the cotton in their grip, to a point where, when the nipper-blade rises, the fibres are taken hold of by a detaching roller g', and a fluted segment on the combing cylinder p. The side of this cylinder opposite to the fluted segment carries a series of 17 combs p, graduated in fineness from 30 to 90 teeth in the inch. Between the fluted segment and the combs, is e. plain space at each side, which affords time for making the required changes between the combs ceasing to act and the fluted segment coming into work, and vice versa', the cylinder revolving continuously. The top comb is fitted above the cylinder; its purpose is to comb the ends of the fibres, and to prevent any being drawn forward, except those that hs re been combed and cleaned by the cylinder. The top comb has only a vertical movement, being lifted out of the way of the cylinder comb when the latter is passing beneath. The detaching roller g, with its leather-covered fellow gl, and the accessory roller g2, receive their motion from a cam, which is arranged to turn the roller g one-third of a revolution backward, then, reversing, two-thirds forward, when it stops until the cylinder-combs have prepared another length of fibre. The reverse movement is given to the roller g for the pur pose of taking back the rear end of the previously combed fibres, so as to place them under, and attach them to, the fibres coming from the combs, to form them into a continuous sliver or riband, it being necessary to detach the fibres under operation from the remainder of the fleece as fed io, and also from the fibres already combed. The attachment having been made, the roller g reverses, and removes the next length of fibres out of the way of the cylinder combs. In order to properly catch the partially combed fibres, the top roller gi is made to move round the axis of the roller g, into contact with the fluted segment of the cylinder P, thus forming a revolving nipper. The top roller 91 is brought into contact by the lever g4 snd its connections by means of a cam at the gearing end of the machine ; it is in contact with the fluted segment only for a portion of the time that the roller g is making the partial revolution forward ; but is always in contact with the roller g.