Modern Cotton Spinning Machinery, Its Principles and Construction

CHAPTER VI. THE CARDING MACHINE.

(103) The scutching process being complete the heavy impurities are practically removed, but there are still to be found in the material the bulk of the lighter ones. The severe treatment of the cotton during scutching adds to the number of broken and short fibres, and also increases the neps. There are also still adhering to the material small particles of broken seed and leaf, which are technically known as “motes.” The removal of all of these is part of the duty of the carding engine. In addition to this, it is requisite to arrange the fibres in what is practically parallel order, as only in this way can a strong yarn be produced. This object is attained by attenuating the “lap,” and then treating its fibres by a number of fine wire points, so as to comb or card them. The objects of carding are, then, briefly stated, three-fold—the completion of the cleansing process, the parallelisation of the fibres, and the attenuation of the fleece.

(104) Cotton was originally carded much in the same way that wool was combed, viz., by drawing a hand comb through a mass of it while held on a table or bench. As soon, however, as the manual art of spinning was superseded by a mechanical process, a similar change occurred in carding. The earliest mechanical carding engine was invented either by Paul or Bourne, about 1748, and shortly afterwards Arkwright developed his roller carding engine, which, in its essential features, is identical with many machines of the present day. A full description of the early development of the carding engine will be found in Mr. Evan Leigh’s work. The invention of the doffing comb, the revolving flat principle (by Jas. Smith, of Deanston); the coiler (by David Cheetham, of Rochdale); and the self-stripping card, all form stages in the growth of the machine. Latterly the attention of machinists has been directed to improving the mode of manufacture and the simplification of details, the main principle of the machine having been fixed for some years. All carding engines have a few essential parts which are common, and it will be better to give a general description of these before dealing with the details.

(105) The perspective view of a revolving flat carding engine, as made by Messrs. Ashworth Bros., given in Fig. 44 (page 63), will enable the description to be easily followed. The lap from the scutching machine is lifted by the iron roller on which it is wound, and the ends of the latter are slipped into the grooves formed in the brackets A. The surface of the lap rests upon a roller C, which is steadily revolved, and is geared with the feed-roller D. The sheet is drawn off the lap from the bottom, and is passed over a polished iron feed-table or plate, which at its inner end is dished. The feed-roller revolves in the curved part or dish of the plate, and is from 2in. to 3in. in diameter, being formed with longitudinal and circumferential flutes along its entire surface between the bearings.

(106) The projecting end of the lap, as it is delivered by the feed-roller, is thrust over the nose of the dished plate, and is struck by teeth fixed on the surface of a roller B, revolving at a rapid rate. The direction of the rotation of this roller is shown in Fig. 46 by the arrow. It is called the “licker” or “taker-in,” and is made of cast-iron, keyed on a wrought-iron spindle, which revolves in bearings fixed to the framing. It is driven from a pulley on the cylinder shaft by means of a crossed belt. It is usually made 8in. or 9in. diameter, and the same width as the cylinder. Its surface is accurately turned, and it is covered when ready for work with a special wire clothing, to which further reference will be made in the succeeding chapter. The licker-in teeth strike off the cotton from the end of the lap, and carry it forward until it comes into contact with the cylinder teeth.

(107) The cylinder E is made from 40in. to 50in. diameter, and from 37in. to 50in. wide. It consists of a cylindrical shell, strengthened throughout its length by small internal ribs, and having near its edges a flange formed. Its position is clearly shown in Fig. 46, and the way in which it is built in Fig. 51. The inner part of the ends of the cylinder and the face of the vertical flanges are bored out accurately by a specially constructed machine. Into each of these recesses a spider is fitted, consisting of a central boss, arms U, and rim V. The boss is first bored to the size of the shaft upon which it has to fit, and the edge and inner face of the rim are turned to a size corresponding with the recess in the cylinder. The two spiders so prepared are fitted into their places, and are then securely bolted to the cylinder. In this way a firm and accurate fit is secured. A mandrill is fitted into the bosses, and the cylinder is then turned truly on its face. After the shaft is fitted in it is sometimes the practice to grind the face of the cylinder, but, if the needful care is taken in turning it, this is not necessary. It is essential that the periphery of the cylinder shall be rigid, but it is equally important that the latter shall not be too heavy. A velocity ranging from 140 to 200 revolutions per minute is given to it, and it is clear that lightness and perfect balance are alike important. After the turning is completed the surface of the cylinder is drilled with a number of rows of holes about half an inch diameter, into which wooden plugs are driven, so as to facilitate the “clothing” of the cylinder. As a rule the latter is balanced, or rather tested for its balance, by running it at its working speed in bearings which slide when the equilibrium is disturbed. When working, the direction in which the cylinder revolves is indicated by the arrow in Fig. 46, and the cotton is carried from the licker-in B to the doffer F, being treated on its way thither by a special set of teeth, the arrangement of which will be hereafter described.

(108) The doffer is a cast-iron roller, 22in. to 26in. in diameter, the same width as the cylinder, and is placed as shown at F. The doffer is constructed and clothed in a similar way to the cylinder. It revolves, as shown by the arrow, in the contrary direction to the cylinder, and at a much slower rate, making usually about twelve revolutions per minute. In this way the carded fibres are transferred from the cylinder to the doffer, and are placed on the surface of the latter in a thin fleece. The removal of the latter is effected by a narrow thin steel blade G, Fig. 44, known as the “doffer comb,” which is fixed on the ends of short arms fastened on a shaft carried by bearings at each end. A rapid oscillatory motion is given to the comb by means of an eccentric or cam, driven from a pulley on the cylinder by a cord or band, the number of beats per minute reaching 1,100. An arc of about an inch long is described by it, and in this way a continuous fleece, called the “sliver,” is taken off the doffer.

(109) The sliver is loosely gathered together into a strand by means of a specially shaped plate, and passed through a pair of calender rollers H Fig. 44 by which it is partially compressed. A slight traverse is sometimes given to the trumpet-shaped tube through which the sliver is taken to the calender rollers. After leaving the latter the sliver is taken upwards to an opening in the plate at the upper part of the frame I. This frame forms part of the apparatus known as the “coiler,” which is illustrated in vertical section in Fig. 45.

(110) The coiler consists of a frame I within which is a vertical shaft V driven by means of the short horizontal shaft from the calender rollers. At the upper end of the shaft a second pair of bevelled wheels are geared, which drive the calender or feed rollers placed immediately below the trumpet-shaped orifice in the cover T, which is hinged as shown. One of the rollers is supposed to be removed in order to show the arrangement more clearly. The sliver entering by the orifice in T and, passing the rollers, is delivered into a short tube X forming part of the plate Z. The latter is driven in the direction shown by the arrows by means of the spur wheel Y gearing with a rack formed on the edge of the coiler plate Z. The sliver is thus given a slight twist, and is delivered into the can W, placed on a plate free to revolve and borne in the lower part of the coiler frame. The can is placed eccentrically to the coiler plate Z, and is slowly revolved in the opposite direction to it, as indicated by the arrows. In this way the sliver is laid within the can in coils, which are peculiarly disposed so that they do not become entangled. Often, within the can, a pair of discs, coupled by a coarsely pitched helical spring, are placed, upon which the cotton is received. The object of this device is to relieve the strain upon the sliver, which would otherwise arise if it were unsupported as far as the bottom of the can. As the weight comes upon the upper disc the spring compresses.

(111) The parts thus described are common to all cotton carding machines, and would remove the major portion of the motes and heavier impurities, but only a partial parallelisation of the fibres would occur; nor would more than a small portion of the short, broken, or immature fibres or “neps” be removed. It therefore becomes necessary to devise a means by which, while the cotton is on the cylinder, it may be treated so that the completion of the cleansing and the arrangement of the fibres are carried out. In order to do this the fibres must be submitted to a combing process, by which, while held by the cylinder teeth, another set of teeth act upon them. The form of carding engine which first found extensive employment, and which is yet preferred by many spinners, is known as the “roller and clearer card.” This machine is illustrated in Fig. 47, as made by Mr. John Mason, in perspective, and in Fig. 46 diagrammatically. After the cotton has been taken from the licker-in B by the cylinder E it is carried past a roller J, known as a dirt roller. The diameter of this is from 5in. to 6in., and it revolves at about eight revolutions a minute. When the fibres are taken up by the cylinder wire, they are partially embedded in the interstices of the clothing, but the motes remain on the surface, from which they are easily removed. The dirt roller J takes these up, and, being covered with a coarser pitched wire than E, the motes become fixed in the former, from which they can be stripped. This can be effected by a hand comb at regular intervals, or by an oscillating comb suitably operated in the way made by Messrs. John Hetherington and Sons, as illustrated in Fig. 48 (page 60). In this case the dirt roller A is driven by a side shaft by means of the worms B and D, the latter gearing into the wheel E, which is keyed on the dirt roller spindle. A cam F fixed on the first working roller gives a reciprocating motion to the rail G by which the comb H is operated, the roller J being thus stripped. An iron tray I is fixed, as shown, into which the strippings fall.

Fig. 46.J.N.

Fig. 47.

(112) After passing the dirt roller the cotton is treated by the teeth on a smaller roller, K, known as a “worker” roller, which revolves in the direction of the arrow. Each worker has a smaller roller, L, placed in contact with it and called a “clearer.” The teeth on the worker have an inclination which is the reverse of those on the cylinder, and any cotton which is not fixed in the wire surface of the latter, or which is flung up by the centrifugal action of the cylinder, is seized by the worker teeth and removed. The worker revolves at a slower speed than the cylinder, its surface velocity being about 20 feet per minute, and varies in diameter from 5 to 6 inches. The clearer, which is 3 or 3¹/₂ inches in diameter, has its teeth set in the same direction as its motion, and its surface speed being about 400 feet per minute, it takes the cotton from the worker and again transfers it to the cylinder. As the surface velocity of the latter is higher than that of the clearer, the cotton is struck by its teeth and is drawn off the clearer and carried forward to the next pair of rollers. It should be pointed out that, although the cotton on the cylinder passes the clearer before it reaches the worker, the inclination of the clearer teeth is such that they cannot take up the fibres; while, on the other hand, the worker teeth are so set that, as previously pointed out, they take up the fibres from the cylinder. Again, the different velocities off the workers, clearers and cylinders cause a series of condensations and attenuations of the fleece to occur. The short fibres and “nep” are laid hold of, and are either sufficiently loosened to be thrown off as “fly,” or are embedded in the teeth of the workers and clearers, which, in consequence, require periodical stripping, this being usually effected manually. The setting of the rollers must be such that they do not approach the cylinder too closely, but simply deal with the fibres thrown up by the revolution of the cylinder. The lighter the carding, provided cleanliness is achieved, the better for the cotton, as with too heavy carding considerable damage is done to the material.

Fig. 45.J.N.

Fig. 48.J.N.

Fig. 49.J.N.

(113) The rollers and clearers are fitted with spindles, projecting beyond the cylinder and framing, and sustained by suitable bearings. On the projecting ends of both worker and clearer rollers, pulleys, with grooved peripheries, are fixed, over which an endless belt or rope is passed, deriving its motion from a pulley on the cylinder shaft. The worker driving pulleys are on one side of the machine, and those of the clearers on the other. The setting of the rollers is important, and it is necessary to make special provision for it. Fixed on the framework of the machine, forming the base S, Fig. 46, is a semi-circular frame, which is known as the “bend.” On this are fitted a number of brackets, the centre lines of which are radial to the cylinder centre, each forming a bearing for one end of the roller spindle. Mr. John Mason employs a special form, which is produced by planing the soles or feet of two of the frames, bolting them together and turning them on the edge. They are reduced to the required diameter to permit of the necessary setting, and when separated form half a circle. Each of these is bolted to the upper edge of the frame, S, which is planed to receive them, and thus a firm and accurate surface is provided for the roller brackets. The latter are constructed so that one portion of them can be set radially, or the whole bracket may be moved, if desired. Semicircular ribs are formed on the side of the bend, through which setting screws, locked on each side of the rib by nuts, pass. In this way the necessary setting can be easily obtained. As the machine is worked the wire points wear, and, when they are sharpened, the relative distance of the centres of the cylinder and rollers is not disturbed. In other words, the space between the points of the teeth on the rollers and those on the cylinder remains unaltered. It is absolutely essential that a definite distance shall be preserved, and means of setting the rollers and clearers readily are imperative. This subject is treated at greater length at a later stage, when the revolving flat-card is described. A bracket made by Messrs. Lord Bros. is shown in Fig. 49, and it will be seen that ample provision is made for both lateral and radial adjustment.

(114) The whole of the worker and clearer rollers are covered by a case, as are also the doffer and licker-in. The emission of fly into the room is thus prevented, and its production materially diminished by the reduction of the disturbance of the air set up by the rapid rotation of the cylinder. The roller and clearer machine is often made with two cylinders, being then known as a “double” card. The cotton, after passing all the rollers placed above one cylinder, is transferred to the second by means of a small drum, similar in construction to a doffer, and known as a “tummer.” The second cylinder bearings are fastened to the framing of the machine, which is made continuous, thus giving great solidity and strength. Double carding is undoubtedly effective in producing a good sliver, and is used in some cases where yarns of a good quality and as fine as 60’s are spun. There has been, and still is, a controversy going on as to the respective merits of the various systems of carding, about which a good deal could be said. In the meantime it is sufficient to note that many spinners continue to put down roller cards in preference to some of the newer types.

(115) At the present time the “revolving flat” machine is the favourite one, and is being widely adopted. The peculiarity of its construction consists in the employment of a number of T shaped bars or “flats” extending across the top of the cylinder, and sustained at each end by the bend, or a plate attached to it. They are coupled by an endless pitched link chain, by means of which they are slowly traversed at a rate of about an inch per minute, in the same direction as the revolution of the cylinder. Referring now more particularly to Fig. 44 it will be seen that during the passage of the cotton from the licker-in to the doffer it is carried below the flats N, each of which has its underside covered with wire clothing. The chain passes round carrier pulleys, one of which is arranged to drive it, being itself driven at a regular speed in the manner shown. Each flat is thus carried over a certain portion of the circumference of the cylinder, and is then turned with its wire face upward. When this happens, an oscillating comb P strips the teeth, and they are then brushed out by the brush Q, usually formed with spirally arranged bristles, and sometimes made of wire. The flats vary in number from 89 to 110, of which there are from 40 to 50 always working. As they are specially constructed, it will be as well to describe the method of doing so at length.

(116) The flats are made of a T section for the greater part of their length, but have flat surfaces formed at each end, as shown in Fig. 51. On these surfaces they travel, and are sustained in their course by the bend. The width of each flat is usually from 1¹/₈in. to 1³/₈in.—the narrower ones being generally preferred—and the length varies with the width of the cylinder. The underside of each flat is made quite level, in order to afford a surface from which the various mechanical operations can be conducted. As the wire clothing is fastened to this face it is obvious that, by making it the base of all subsequent treatment of the flat, a decided advantage is obtained. The first operation is that of milling two surfaces at the upper side of each end of the flat, at the same time trueing up the faces of the ears to which the chain is attached. A double-ended machine is used, fitted at each end with an instantaneous grip chuck, at the bottom of which is a steel face on to which the ends of the flat are placed, the flat having been previously stretched and straightened. The flat is then cramped down, and the cutter brought into operation. The flat is placed on the faces thus formed in the next machine, which is constructed with chucks at the end of two long radius arms. A cross spindle has a worm fitted on it, which gears with a segment at the end of the arms, and by revolving which the flat is brought under the cutters, and has a hollow cut into it of the desired radius. The flat is then chucked edge up and milled by a cutter on its upper side at the ends, so as to provide the necessary clearance for the chain. The next operation is to cut out, by means of a similar machine to the one with the long radius arms, the under surface of the flat end, which had been treated by that machine, so as to leave two surfaces on which the flat travels, the radius arms in this case being shorter. These surfaces have two objects—to lessen the friction when the flat is travelling, and to allow of the flat having the necessary heel given to it. The flat is then cramped down on the surface thus formed, and the snugs are drilled by a double-ended machine fitted with an automatic motion for withdrawing the drill. By the same machine the hole is tapped, the tap reversing when it has gone the requisite depth. After drilling the flat along the edges in order to enable the clothing to be fastened, it is complete so far as its treatment by machines is concerned.

(117) There are one or two things to notice in respect to the operations just described. The first is, that all the faces are formed from that on which the wire clothing is subsequently placed, and that consequently the flat when traversing is provided with working surfaces which ensure it being parallel to the cylinder all across, provided the bends are correctly set. This is, as will be seen, an important point. Again, the whole of the surfaces to which the chains are attached are true with the flat ends, so that there is no tendency to pull the flat askew. Having thus constructed, by the means indicated, the flat as perfect as is possible by machine, it is necessary to put the “heel” in, and also to correct any twist which may have arisen by the spring of the flat whilst being milled. There are two methods of testing this point, one mechanical and the other electrical. As will have been noticed from the description of the method of milling the flats, two parallel surfaces are formed at the upper and lower side of each end of the flat. It will be evident that, if the flat is placed upon either of these surfaces and tested by a suitable apparatus, the other surface should be as nearly as possible parallel with the first. In order to see that this is so, the flat is placed face downwards on two steel faces perfectly parallel with each other. At each end of the table carrying these faces is an indicating apparatus consisting of a graduated scale and two pairs of compound levers, so arranged that a slight inaccuracy is multiplied to a large extent. If, therefore, the flat is laid on the blocks and the points of the levers are allowed to fall on the four surfaces left after the flat is milled by the long and short radius machines, the setter can see at a glance if the surfaces are accurately formed. In practice, the two ridges or surfaces at the front of the flat—that is, the edge nearest to the doffer end of the card—are reduced somewhat by hand, thus throwing up the back edge. This is what is known as giving the “heel” to the flat, and its object is to leave a slight space between the wire points of the flats and cylinder at the back of the flat, while at the front these are as close as possible together without touching. The object of this is to prevent a rolling up of the strippings and cotton fibre, which has been found to exist where the wire at the back or “toe” of the flat nearly approached that of the cylinder. The heel having been given the flat is then tested by the apparatus described, but instead of all the fingers corresponding, this only occurs with the two which are in contact with the same surfaces on each edge of the flat. One pair registers the variation caused by the heel and should correspond, while the other pair registers the position of the untouched surface and must also correspond. This device is the one most commonly used, and gives very accurate results. Messrs. Howard and Bullough adopt an electrical test which is also said to give good results. Similar devices are used in some cases to set the bends accurately with the cylinders; in others a simple scriber or pointer being used and set down, so that a small slip of steel can be easily moved across the bend under its point. As the latter is carried in a bracket fixed to the cylinder the bend can easily be tested all round. Messrs. Howard and Bullough use an electrical scriber, contact with which rings a bell, and thus indicates the point requiring adjustment. The use of the graduated indicators as shown in Fig. 60 enables this to be easily made, and delicacy of adjustment attained.

Fig. 44.J.N.

(118) As the function of the flats is to remove by means of the wires attached to them the short fibre and nep, the more accurately the distance between the wire clothing on them and the cylinder is preserved, the better will be the effect produced. In order to attain this object it is necessary that the flats should be specially constructed and carried. A reference to Fig. 51 will show the construction of the flat, which is so finished (as was explained in paragraph 116) that the faces upon which it travels are parallel with the face upon which the wire is fixed. Thus, if the flat is borne upon a surface which is concentric with the surface of the cylinder, but so far from the centre of the latter as to compensate for the length of the wire on both, and provided that the two wire surfaces are accurately and evenly ground, it will be clear that over the whole of the surface there will be the same distance between the points of the wires. This is the condition which is absolutely the best for carding, but its constant maintenance is the problem. The flat course may be either formed on, or attached to, the frame O, and in either case is technically termed the “bend.” This phrase is often very indifferently used, and is sometimes applied to the framing O when the latter is acting as a support for the flats, and sometimes to the surface attached to or borne by it for the same purpose. It ought, however, to be insisted on, for the sake of clearness and definiteness, that the phrase “bend” should only be applied to that portion of the mechanism upon which the flats actually travel. If it be assumed that a machine is in condition for starting for the first time, that the surface of the flat end upon which it travels is set back from the flat wire surface ¹/₂ inch, and that the wire projects ¹/₂ inch beyond the cylinder surface, there is a necessity for a circle with a radius of 26 inches. It is, of course, perfectly easy to form a track on the edge of the frame O, which should be accurately machined so as to be quite concentric and of the radius required, in which case the required distance between the two wire surfaces could be perfectly established. But, during the operation of the machine, the wire points become blunted and no longer deal with the cotton as efficiently as they ought. This necessitates their re-sharpening by grinding, which involves a reduction of the size of the circle described by the points of the cylinder wire, and an enlargement of that described by the covering of the flats. As has been pointed out, it is better that the two wire surfaces should approach one another as closely as possible without touching, the most effective results being obtained in this way, and it therefore becomes necessary to find some method of lowering the flats in order to re-establish these conditions. This is precisely the difficulty which has to be overcome. It is perfectly clear that any flat course formed on the frame O cannot be so adjusted, and it is essential that some other adjustable surface sustained by O shall be found. If for a minute or two the work to be done is considered it will be seen that there is a very difficult problem to solve. If a circle is struck 51 inches in diameter, and at the same time a second circle 52 inches in diameter is described, from the same centre, some idea can be obtained of the actual conditions of the case. Supposing that the circle 51 inches diameter is reduced to 50¹/₄ inches (this representing the extreme variation in size arising from grinding), it will be at once observed that the dropping of the 52 inch circle in a radial line will be followed by the destruction of its concentricity with the other. In the case thus supposed the smaller circle represents the surface of the wire on the cylinder, while the larger one represents that of the ring upon which the end of the flats traverse. Now, while the former is reduced with ease by grinding, the latter is not so easily reduced, and the action of moving it nearer the centre, without its reduction, simply means that its centre is moved to the same extent, while the centre of the ground surface remains constant. In other words, the concentricity of the two circles is destroyed. As the concentricity of the flat course with the cylinder is absolutely essential, in order to get that close approach over the whole of the wire surfaces which has been shown to be necessary, it follows that its destruction implies ineffective and bad carding.

Fig. 50.

(119) The arc occupied by the flats in their traverse varies from 120 to 150 degrees, speaking roughly, so that in some way or other a flat course of that length, capable of adjustment, requires to be provided. By far the most common method of providing this is to fasten to the side of the machine at the upper edge of the frame O a flat plate, shown in Fig. 50, with its upper edge forming a segment of the circle required. This arrangement is the invention of the late Mr. Evan Leigh, and has been widely adopted. The shape of this plate, so far as its depth is concerned, is so arranged that it can be sprung or compressed into a smaller circle with the minimum amount of difficulty and strain. This is what is known as a “flexible” bend, and is in wider use than any other form. It is attached to the frame side by bolts, slots being formed in the bend casting at each end through which the bolts pass. It will be seen that the slots allow of a considerable range of movement in the bend, which is made use of in setting it after the wire has been ground. The setting is effected by springing the bend by means of screws, until a circle is formed equal to that required to enable the wire surface of the flats to be concentric with the wire surface of the cylinder. As a matter of fact, the setting is done by the carder by sound and by the use of a gauge, the combination of which permits him to ascertain fairly accurately that the flats are in a good working position. When the bend is set, it is locked against the frame by the bolts, and stops, which are placed midway between the points of support, are brought up to the under edge of the bend. The object of these is to uphold the bend, so as to avoid deflection from the weight of the flats. As the cylinder, which weighs 9 or 10 cwts., revolves always in one direction at a steady rate of 140 to 170 revolutions per minute, and as the pull of the driving strap is usually towards the front, it will be perceived that a tendency, at least, will always exist towards wear in the brasses at their front side. Thus it is possible that in addition to the necessity for providing for the lessened circle, it may be also requisite to take into account the movement of the centre in a horizontal direction. The latter difficulty, however, has been to a large extent overcome by the elongation of the bearings, which are now much longer in proportion to the diameter than was the case formerly. The special construction of the bearings in order to resist the action of wear or to afford means of setting will be treated at a later stage in this chapter.

(120) It has been the ordinary practice to place the flexible bend outside the framing, but it is becoming the practice to decrease the width of the cylinder, and consequently the length of the flat. The cylinder is now ordinarily made 37in. wide when fed from 40in. laps, the lap being narrowed as it approaches the feed roller by specially placed and designed guides. By diminishing the length of the flat, the tendency to deflection is also lessened, and, in addition to this, an improvement occurs in the selvedge of the sliver. It will be seen that in diminishing the width of the lap 3 inches, it is only possible to do so by squeezing in its edges or folding them over somewhat. Thus any thin place on the edge of the lap is thickened, and the sliver when produced has a better selvedge. This advantage is partially derived by the means mentioned, but there is a further cause of ragged selvedges, to which a good deal of attention has been given. Usually between the edge of the cylinder and the bend a space has been left, through which, when the cylinder is revolving, a current of air is induced. As the cotton is held in the wire clothing, which comes right up to the edge of the cylinder, the suction thus caused draws it out and causes ragged places. Messrs. Ashworth Brothers remedied this defect by the employment of a circular shield about the height of the cylinder wire, which is fixed to and revolves with the cylinder. This gap is now entirely closed by all makers.

Figs. 51 and 52.

(121) Messrs. John Hetherington and Sons adopt the plan shown in Figs. 51 and 52, which are cross sections of the cylinder, bends, and flats. Fig. 51 represents the old method of construction. The flat T is sustained by the flexible bend Z, which is controlled by the setting screws W, and is attached to the framing Y by the bolt shown. The cylinder V in this case is 40in. wide, and between it and the fixed bend a space is left, which is filled up by the introduction of the wood packing X. The latter is fastened to the fixed bend Y by screws as shown. The new plan is shown in Fig. 51. In this case the flexible bend Z is fastened on the inside of the framing Y, the setting screw W being placed as shown. It will be seen that the edge of the cylinder V comes close up to the bend Z, and no induced air current is possible. The cylinder is reduced to 37in. wide as previously mentioned. The same firm adopt a very good method of dealing with the flexible bend, which is shown in Figs. 53 and 54 in transverse section and side elevation respectively. On the cylinder shaft a segmental rack V is fixed, which is driven by means of worm gearing, and the bands W U from the pulley X placed on the shaft. This also drives a spindle Z, borne in frames attached to the cylinder, on each end of which is a milling cutter. The cutters are kept in contact with the flexible bend Y, which is made a little larger than is necessary, and is bolted in its place after being accurately set. It is weighted with suspended weights R T, together equal to the weight of the flats when resting upon the bends, and attached to the bends at points midway between those at which they are set. In this way the actual conditions of working are established as nearly as possible before the mechanism is started. On commencing operations the milling cutters are at one end of the bend, and the cylinder is slowly revolved so as to traverse them over its surface. In this way it is accurately shaped to suit the conditions of the case, and is as true as a fixed bend could be made. Of course, as soon as the bend requires to be reset it is necessary to adopt the ordinary plan, but the treatment described undoubtedly facilitates subsequent setting.

Figs. 53 and 54.J.N.

(122) The plan adopted by Messrs. Platt Bros. and Co. Limited is shown in Figs. 55 and 56, the former being the new, and the latter the old, method. A perspective view of this machine fitted with the new bend is given in Fig. 57. Dealing with Fig. 56 first, the cylinder A is separated from the framing B by the distance shown, this being filled up by the wood packing G. The flexible bend C is fastened to the framing on the outside, and is set by the screws shown. The cylinder in this case is 40 inches wide, and it will be noticed that the arms of the cylinder are level with its edge. In Fig. 55 the cylinder A is recessed so that it projects beyond the arms sufficiently to permit the bend B to come within the recess. The flexible bend C is attached in the manner shown to B, and is fulcrumed on the pin in its centre. The setting is obtained by means of the screws, as in the previous case. The clothing on the flat is secured at the ends by the clip or plate F, shown separately in side view and plan, and a thin plate E is fastened to the cylinder by which means the ingress of air is quite prevented. There is also a reduction in the widths of the cylinder and machine, in the latter case about 8 inches, so that a machine fed from a lap 45 inches wide occupies only the same space as a machine made on the old principle with a 40 inch lap.

Fig. 57.

(123) Before leaving this point there is one thing to be noticed which is important. A reference to either Fig. 52 or 56 will show that the chain is attached at the end of the flat immediately over the bend, whereas in Figs. 51 and 55 it is further from it. The former method is best, as being less likely to deflect the flat, and is being adapted to the new construction by both the firms named.

(124) The construction of machines with flexible bends, in spite of many objections which are continually being alleged, continues to be large. It is held by some spinners and machinists that the necessity for adjusting the flexible bend manually from three points is faulty, and that it is better to provide mechanism whereby the setting can be made by positive means and from one point. Several patented arrangements with this view have been made, and illustrations of most of them are given. In most cases a flexible bend—somewhat differently constructed—is used, although it does not always have that name given to it.

Figs. 55 and 56.J.N.

(125) In Figs. 58 and 59 the arrangement used by Messrs. Dobson and Barlow—to which the name “Simplex” is given—is illustrated. Fig. 59 is a side elevation of that portion of the machine where the bend is applied. Fixed to the framing Q of the machine are four brackets P, O, M, L, the last three of which are specially curved on their upper edge, while P is shaped to a curve on its inner surface. Fixed in the metal strip K—which is practically the flexible bend—are four pins, each bearing an anti-friction runner, which are kept in contact with the edges of O, M, and L, and with the inner surface of the bracket P respectively. Attached to K, at the opposite end to P, is the crank S, oscillating freely upon a pin fastened in the frame Q. At the end of the bend K, where it is controlled by the bracket P, and, on its inner edge, a toothed rack is formed, with which a small spur pinion engages. The pinion is fixed on the axis of a worm wheel R, rotating on a pin fastened in the framing Q. With the wheel a worm R¹ gears, and this can be rotated by a handle to any desired extent. When the bend K is moved by means of the rack in the direction of the arrow, it is put into tension, and the anti-friction bowls are drawn down on to the surfaces of the various branches. A glance at the detached sectional view given will show that the various brackets overlap the bend K, which slides between them and the frame Q. The position of the bend is arranged so that between it and the edge of the cylinder there is no open space left.

(126) Having thus described the actual mechanism a few words can be said about Fig. 58, which is a diagrammatic representation of it. The circle A B is that formed by the edge of the bend or plate K when it is at its highest position—that is, when the wire is unworn. The circle D E is that described by the edge of K when it has been drawn down to allow the flats to come nearer the cylinder. The small black dots represent the pins fixed in the bend K. When the latter is moved by the action of the rack and pinion, the end of the crank S follows the path of the circle described by it, moving from B to E during the time the entire depression of the plate is made. The anti-friction bowls in the same period travel in the paths shown, and it will be noticed that each of the curves is differently shaped. If the inner circle F G be supposed to represent that occupied by the edge of K after the crank end has travelled from B to G—a half circle—the curves L M O P would, if prolonged, be of the shape shown. Having obtained them in the manner thus described on paper, they are actually reproduced on the brackets by a milling machine fitted with a copying arrangement. By forming an indicator scale on the worm wheel R the amount of movement of the bend K can be regulated as desired to any degree of accuracy. The proportions of the worm, worm wheel, pinion, and rack, are so arranged that the advance of the wheel ¹/₅₀th inch will raise or lower the bend K ¹/₂₀₀₀th inch. This method is very simple and effective.

Fig. 60.

Figs. 58 and 59.J.N.

(127) The arrangement adopted by Messrs. Howard and Bullough has the central idea of the employment of inclined surfaces, by withdrawing one of which the other can be lowered. It is shown in front elevation in Fig. 60 and in section in Fig. 61. The fixed bend has formed on one side of it a broad flange, which is turned to a true circle on its upper edge. Upon this a segment of a ring A is placed, which can be slid in or out by means of the screw B and lock nuts. The back nut is riveted to the index disc E, which is divided into 36 spaces, the front lock nut securing the arrangement after setting. In front of the dial plate E an indicator finger D is fitted, which points out any alteration of the circular dial plate E. Upon the upper surface of the ring A a second ring C of a smaller section is placed. C is accurately turned on its inner side to correspond with the inclination of the upper surface of A, and on its outer edge is horizontal, so as to form a course for the end of the flat. The ring C is pressed down upon A by the weight of the chain of flats as they pass over it. The action of this mechanism is easily understood. By withdrawing the segmental ring A, by means of the screw B, the flats are lowered, the degree of their depression being sufficient to preserve the necessary distance between their wire teeth G and those F upon the cylinder H. The adjustment can be made in either direction, and the graduation of the dial E enables it to be finely made. In this case also, as shown in Fig. 55, the gap at the end of the cylinder is closed by bringing the flange of the fixed bend close to the edge of the cylinder.

Fig. 61.J.N.

Fig. 62.J.N.

(128) In Figs. 62 and 63 a plan invented by Mr. Thomas Knowles, of Bolton, and made by Messrs. John Tatham Limited is illustrated. This consists of the employment of a wedge-shaped segmental ring, which rests upon the upper edge of the fixed bend, and can be drawn along it by means of the screw shown. The ring is pierced by a number of holes of decreasing diameter, and a small slit is made through the web left between the lower part of the hole and the inner surface of the ring. The latter is thus rendered easily flexible, and the mere weight of the flats is sufficient to make it accommodate itself to its supporting surface. The ring is shaped so that the inner edge forms part of a spiral curve, shown diagrammatically in Fig. 63, and with its outer edge levelled so as to bear the flat. In like manner the edge of the fixed bend is shaped to the spiral curve, both of these being obtained by the use of a circular milling machine fitted with the necessary shaping mechanism. The spiral curve to which the two surfaces are formed would, if continued far enough, terminate in the centre of the cylinder, so that if it were possible to traverse the ring far enough it would actually cross that point. The action of setting this mechanism is simple. The ring is drawn downwards by the screw, and its outer edge thus moves nearer the centre of the cylinder to an extent corresponding with that of its traverse. Any adjustment desired can thus be given in either direction.

Fig. 63.J.N.

Fig. 64.J.N.

(129) The machine made by Messrs. Ashworth Bros., of which a perspective view was given in Fig. 44, is based upon an entirely different principle. Before passing on to describe it, it is only fair to say that to this firm belongs in great measure the great advance which has been made in the construction of this form of machine. They recognised the importance of accurate mechanical construction, with the result that they produced a machine which could be run at much higher velocities than had hitherto been thought possible. Referring now to Fig. 64, on the top of the fixed bend B, a number (about 15) of thin steel bands E are placed, being held at one end by the stud G and kept in tension by the screw C, thus being firmly drawn into position. The bands are of various thicknesses, from ¹/₃₀th to ¹/₁₀₀th inch. The end of the flat traverses on the top band F, and any of them can be removed and replaced by a thinner one. Thus the concentricity of the flat course is preserved, provided that the amount of wear to be taken up corresponds with the difference between the thickness of the band taken out and that replacing it. It may happen that the amount of wear to be provided for is not enough to justify the removal of the band, which, on account of the necessary labour involved, takes some little time. In order to afford a ready means of making the correction, and at the same time avoiding the replacement of the bands, the makers have adopted the bold but ingenious plan of forming the cylinder bearing so as to be adjustable vertically. Referring now to Fig. 64 it will be noticed that the engine bend and the pedestal are cast in one piece, bolted on to the lower frame. The pedestal cap is fastened by means of set screws, but the bottom brass can be lifted by means of the vertical screw shown in dotted lines. This screw is fitted into the pedestal, which is tapped to correspond, and has at its lower end a ring which is divided into 100 parts on its circumference. An indicator finger is fitted so that the ring can set to any of the divisions as desired, and when so set the screw can be locked by a lock nut. By proportioning the pitch of the thread it is clear that any desired lift can be obtained. The pitch adopted being ¹/₁₀th of an inch, a revolution of the screw one division on the ring would mean a vertical movement equal to ¹/₁₀₀₀th of an inch. Now it is quite true that in a sense any vertical movement of the cylinder destroys the concentricity of the flats, but this, after all, is a relative matter. If reference is made to a drawing showing the arc occupied by the flats in various positions, it will be seen that with a total fall of ³/₈ths of an inch the difference between the ends and centres of the arcs described does not amount to a great deal. Therefore if the cylinder was raised by the screw about ¹/₈th inch it would not amount to an inaccuracy of any magnitude. But as the thickest band is only ¹/₃₀th of an inch thick it would be most likely that instead of lifting the cylinder anything like ¹/₈th inch a band would be taken out and the wear thus compensated for. The raising of the cylinder ¹/₃₀th of an inch would practically mean that the setting of the flats would remain unaltered.

Fig. 65.J.N.

(130) In Fig. 65 is given a side elevation of one side of a carding engine, in which the bend is made in an entirely different manner to any previously described. This is really a revival of a plan which was suggested many years ago by James Smith, of Deanston, but which was dropped on account of certain difficulties in adjustment which are now overcome. The machine as illustrated is made by Mr. Samuel Brooks, and is nearly the latest form put on the market. The pedestal A has a circular flange formed on it about midway of its length, to which a bush C can be bolted by the three bolts M. The bush is placed over the inner boss of the pedestal, and can be set in its proper position, which may be ascertained at any time by the pin J, passing through a hole in the pedestal flange and one in the bush when the latter is quite concentric with the cylinder, and only then. On this bush a wheel D, with a flat periphery, is fitted and revolves. The periphery E of this wheel sustains the flats F, the traverse of which cause it to rotate at precisely the same circumferential speed as that of the flats. The friction of the flat ends is in this way avoided, which is claimed as one of the important features of the new arrangement. When the machine is new the diameter of the wheel D is of the exact size needed to sustain the flats, and keep the wire points the requisite distance apart, theoretically, ¹/₁₀₀₀th inch. But when the wire has worn and has been re-ground, it is, of course, necessary to reset the flats. This is effected by means of the milling cutters G, placed as shown, which can be set in by the arrangement shown in side elevation in Fig. 66, and in partial section in Fig. 67. The cutter G is fixed on a shaft borne by the bracket F, which is attached to the bend, and is moved inwards in a radial line by the screw H, the latter being arranged on the micrometer principle. The screw is threaded 25 to the inch, and the worm wheel I has 20 teeth. The rotation of the latter one tooth implies a corresponding movement of the cutter G ¹/₅₀₀th inch. By subdividing the disc K on the spindle carrying the worm L, as much as desired, the cutters can be moved in or out to a very slight but ascertainable degree. A similar arrangement is fitted to the bush C, by which when unlocked it can be lowered as desired.

Figs. 66 and 67.J.N.

(131) In setting, or, rather, in lowering the flats—because that is practically all that can be done by this arrangement—the bush is unlocked and the pin J taken out. It, with the wheel, is then lowered until the wires on the central flat and those on the cylinder can be heard to click. A careful note is taken of the amount which the bush has been lowered, and it is again raised to its central position and locked. Suppose that the amount was ¹/₂₅₀th inch—a very extreme supposition—then the distance the flats have to be lowered is that distance less ¹/₁₀₀₀th inch, the standard distance between the wire teeth, or ³/₁₀₀₀th inch. The disc K is therefore revolved 1¹/₂ times, which moves the cutters G inward to that extent, and, in consequence, the diameter of the wheel D is reduced, so as to provide a course for the flats of the exact size required. The cutters G are driven by a band from the cylinder shaft, and the wheels C are traversed as usual during the process of reduction. This arrangement is a novel one, but it is clear that, if successfully carried out, it provides a perfectly concentric flat course.

(132) Before proceeding further, and dealing with another form of machine, a few words may be said on the subject of setting the flats. It has been shown that in many cases a delicate indicator and micrometer screw is fitted, by which it is claimed the most exact settings can be made. There can be no dispute as to the power to do this which is thus provided, the only question is whether the circumstances of the case call for it, and whether in actual work any such accuracy is obtained and maintained. There are four points where adjustment is required in a carding engine. These are between the dish feed plate and licker-in; between the licker-in and cylinder; between the cylinder and flats or rollers; and between the doffer and cylinder. Messrs. Platt supply three gauges, respectively ·013, ·011, ·007 of an inch thick. The finest of these it will be seen is ⁷/₁₀₀₀ths of an inch thick, so that in this case at least the theory as to setting to ¹/₁₀₀₀th is disregarded. In adjusting the flats, by far the commonest plan is to do so during the time the mill is standing, when everything is quiet. The bend is then dropped until the gauge which it is intended to use can be pushed between the two sets of teeth. If it is afterwards desired to get very fine setting, the bend is lowered until the slow revolution of the cylinder produces a “click,” which shows that the teeth of the cylinder and flats are in contact. A little elevation is given to the bend so as to leave a space between the teeth. A skilful setter can tell at any time by the “touch” of the teeth if they are too closely set, but the vibration existing during working hours may disturb his observation. When an indicator is used the practice is to establish the clicking point, and then turn back the screw until the flats are raised the desired distance.

(133) It is questionable whether it is possible to maintain so accurate a setting during actual work over a long period after wear has begun. It is hardly likely that many machines continue to work with this close setting. The practice is rather the other way. Wider spaces than ·011 are common, and it is unreasonable to expect anything else. The function of the wires on the cylinder being to seize by means of their points the fibres of cotton and bring them under the influence of the flats, it is obvious that the question of efficient carding turns very largely upon the charge of cotton in the wire. If light carding is taking place—that is, if little cotton is passing over the cylinder during a fixed time—the delicate setting is both possible and desirable, as it would result in the cotton fibres being thoroughly combed from end to end. But if the cotton is fed rapidly, so that the cylinder becomes highly charged and its surface covered with a comparatively thick fleece, a too close setting would result in considerable damage to the fibre. As the prevailing practice is generally based upon commercial considerations, the last is the more usual condition existing, and extremely close setting is in this case both impracticable and undesirable.

(134) Even if this extra fine setting named were adopted there is nothing to show that it cannot be attained with the flexible bend. True, the setting of the latter involves a little more labour, but is it quite demonstrated that it is not necessary labour? The construction of flexible bends is now such, as has been shown, that their flexure, ³/₈ths of an inch, is made with absolute ease and accuracy by means of the setting screws. There is an old adage that “the proof of the pudding is in the eating,” and no candid person will contend that carding engines made with flexible bends of the Leigh type produce either worse slivers or make more waste than others. On the other hand, it is only fair to say that the converse of this proposition holds true, and that good slivers are obtained from machines made with indicators and special setting appliances without more waste being made than in the case of flexible bend machines. It is, however, more than probable that the system of setting by the ear is adopted in every case of successful carding.

(135) A further consideration in connection with this question is the problem of adjustment after the cylinder bearing has worn so as to alter the position of the centre of the cylinder. In this case the cylinder can be followed by the flexible bend and concentricity re-established, whereas, in the case of other arrangements which are based upon an unyielding surface attached to the framing, no such practice is possible. In this case it is necessary to provide a means by which the cylinder centre can be restored to its original position. The methods of doing this will be touched upon at a later stage.

(136) Before leaving the question of setting, it may be stated that the distance between the licker-in and the dish feed-plate is regulated according to the quality of cotton treated. Ordinarily the thickest gauge ·013 is used by Messrs. Platt, but if the cotton is deficient in strength the distance is increased by the thickness of the medium gauge, or in all is made ·024 inch. The licker-in is set by the medium gauge ·011, which is slipped easily between the licker-in teeth and those on the cylinder. The space left between the doffer and cylinder teeth is smaller, the finest gauge ·007 being employed in this case.

(137) In paragraph 132 it was stated that setting was mainly conducted by means of a gauge and by ear. It is often desirable to ascertain during work how the flats and cylinders are set relatively, and it is highly desirable to do this without disturbing the flexible bend. Up to quite recently this could only be done by gauging at each end in the ordinary way, and in the centre by the ear. Messrs. Platt Brothers and Company have, however, devised a method by which the setting of the flats can be instantaneously ascertained, and power is thus given to a spinner or overlooker to check the setting. In the flexible bend, at four points, narrow oblong slots are formed by casting, and are made of such a width that the carder’s gauge can be easily slipped between the cylinder and flat teeth, whatever may be the condition of the wire. The slots are, during work, stopped by plugs, which can be instantaneously withdrawn. The makers state that they have made careful tests to ascertain whether the presence of the slots affects the deflection of the bend, but do not find any ill effects. This is an extremely simple but very valuable improvement, and affords an opportunity of checking the setting, which cannot but be beneficial.

(138) The third form of carding engine is that known as the “Wellman,” or “Self Stripper.” It is extensively employed on the Continent, and in the United States. It is the direct descendant of Paul’s machine, inasmuch as it is based upon the principle of the employment of fixed flats superimposed upon the cylinder. In the early days of carding machines the flats surrounded a certain portion of the cylinder, and when they became charged with fly were lifted and stripped by hand. This practice was found to be very inconvenient, and a method of raising the flats automatically was therefore welcomed. For the finer counts of yarn cards on this principle were extensively employed in England, but the improvement of the revolving flat card has displaced it, and in this country at least it may be looked upon as an extinct type. The mechanism of the Wellman is ingenious, but for the reasons stated only a brief description of it will be given. Students who are interested in the subject can study it in the works of Mr. Evan Leigh in English, Mr. Neiss in German, or in one or two French books.

(139) The self-stripping card as made by Messrs. Dobson and Barlow, is shown in side view in Fig. 68. The flats A cover the surface of the cylinder for about the same extent as in the revolving flat card. They are, however, stationary, and rest upon brackets B, each of which is capable of separate and delicate adjustment. On the cylinder shaft C an arm or lever D is placed, which is free to oscillate as required, its position being regulated by a pinion engaging with the rack E. The motion is driven from a grooved pulley, fixed on the cylinder shaft, which gives movement to a wheel behind the catch plate or wheel F. A sliding jaw traverses in the long slot at the top of the arm D, and is raised by a cam fixed on the spindle of the wheel F. When this upward movement of the jaw takes place the flat is lifted and held tightly between it and a fixed jaw formed on the arm D. While in this position the lever G, hinged at its lower end to D, is drawn inwards, and as it carries a wire stripping brush H it causes the teeth of the latter to pass through those of the raised flat, and thus remove the dirt and short fly. Immediately one passage is made the brush returns, and the flat is at once lowered into its position above the cylinder. By an extremely ingenious arrangement of mechanism the flats are not stripped consecutively, but are arranged to be stripped oftener near the licker-in than at the doffer end. The reason of this is obvious. By virtue of their position the earlier in the series of flats retain more dirt, and therefore require stripping oftener.

Fig. 68.J.N.

(140) From the mechanical point of view, the Wellman card and its predecessors will repay careful study, but as stated in paragraph 138, it has ceased to be used in England, and does not, therefore, come under the head of “modern” machinery. Yet there are principles involved in the Wellman which are of high merit and importance, and a system of carding is possible on this machine which is not possible on any other. To begin with, the distance of the flats from the cylinder may be varied at will, and instead of each flat being concentric with the latter, the circle described by the series may have another and distinct centre. That is to say, the flat at the feed end could be ¹/₈th inch away from the cylinder, while the one at the doffer end approached within ¹/₅₀₀th inch, all the intermediate ones being set proportionately. Again, the pitch of the wire teeth upon the various flats can widely vary. Those at the feed end may be, and often are, much coarser than those at the delivery end, a proportionate gradation of pitch occurring throughout the whole series. It will be at once seen that the conditions prevailing in a revolving flat machine are entirely contrary to this practice. In that machine the setting of all the flats is devised so as to make them equidistant from the cylinder centre, and every flat must of necessity be covered with wire clothing of the same counts.

(141) The effect of the peculiar setting referred to is, that, as the cotton is carried round by the cylinder, the fibres are gradually straightened by a series of combs which are at once nearer to the cylinder surface and finer in pitch, as the doffer is approached. Supposing, for instance, the pitch of the teeth on the first flat was ¹/₈th inch and their distance from those on the cylinder also the same, it would follow that the fibres flung up by the rotation of the cylinder would be at most only lightly treated. If, however, the pitch of the teeth and their setting became gradually finer, until the latter was reduced to ¹/₅₀₀th inch, it is easy to understand that the fibres would be, by a series of grades or steps, carded or combed. This treatment, on account of its gradual nature, results in the fibres being drawn out very straight, and is, when properly conducted, the nearest approach to combing which has been attained on a continuous carding machine. For the longer stapled cottons the use of a machine by which settings of gradually increasing fineness are obtained is especially suitable, and it was for these that the machine was mostly employed. Of course, the figures given above are merely hypothetical, and are used only to illustrate the point at issue.

(142) The defect of the Wellman machine in modern eyes is principally its slow velocity. The great weights which are now obtained from revolving flat cards cannot, or at any rate have not, been obtained from the self-stripper, and, in consequence, the latter has become discredited. But it must not be forgotten that the former machine has had an amount of mechanical skill lavished upon it which has been absent from the latter. This does not mean that the Wellman has not been well made, but it has not been so well constructed as the revolving flat type has during recent years. It is quite within the bounds of possibility that the self-stripper may have a revival, when its undoubted capability for good work may be combined with great productive power. It is often combined with a roller machine and used as a finisher carding engine, and is in other cases fitted with two or three rollers before the flats are reached.

(143) Reference was made in paragraph 105 to the use of a dish-feed. In Fig. 69 illustrations are given of this part of the mechanism, as made by Messrs. Dobson and Barlow, this being a reproduction of an illustration contained in a pamphlet on “Carding,” by Mr. B. A. Dobson. It will be seen that the feed-roller A revolves in the curved portion of the plate C, and that the nose of the latter is specially shaped to suit various classes of cotton. The principle involved here is precisely that referred to in paragraph 94 in dealing with the scutcher feed. The shorter the staple the more acute the surface from which it is struck can be without damaging the fibre. While a long fibre will permit of bending round a roller or lever end of large size, the shorter stapled varieties will simply be dragged downwards and crushed with precisely the same treatment. A close examination of the three views marked K, G, and R will illustrate this point, these being respectively for Surat, American, and Egyptian cotton. The adoption of the dish-feed is one of the most important of the minor improvements made in the carding engine, and leads to the straightening out of the lap end, owing to the exactitude of the rate of feed which can be attained. For the full success of this appliance it must be used in conjunction with the saw tooth on the licker-in, a description of which is given in the next chapter. This is a description of tooth which does not become charged or choked with dirt, nor does it require grinding, so that it is always in condition to deal effectually with the cotton. The action of this class of tooth is very graphically shown in Figs. 70 and 71, two reproductions of photographs in Mr. Dobson’s paper above referred to, of a lap end before and after the licker-in has acted upon it. They very clearly demonstrate the enormous effect produced by the licker-in teeth, and show how effectually all dirt and motes are removed.

(144) Again referring to Fig. 69, it will be seen that below the dish C two blades or “mote knives” are placed, which can be readily adjusted so as to present a sharp edge to the cotton as it is flung down by the licker-in, and so scrape off the “motes” from its surface. The object of these knives is similar to that of the leaf extractor used in a scutcher, and described in paragraph 77. Beneath the licker-in and beyond the knives a casing E is placed. These are usually made of tinned iron, and form a sort of grid through the interstices of which the droppings can fall. From their position they are known as “under casings.” The exact setting of these is a matter of high importance during working, and should be ascertained by observation when dealing with different classes of cotton. It has been found that the use of under casings with the licker-in has been attended with considerable economy. They are also used beneath the cylinder, and should be as carefully set as is the case with those under the licker-in. In determining the distance, regard should be had to the quality of cotton used and its length of staple, as, if the fibres actually strike the bars of the grid, they may adhere to them and partially choke the latter. On the other hand it is found that too wide a setting is followed by increased waste. It is both possible and advisable to find the golden mean by observation. Messrs. Platt Brothers and Co., Limited, have a special way of forming the undercasings, the bars of which are secured to turned wrought iron segmental rings, the position of which can be regulated from outside the machine by special setting screws. They also attach the licker-in casing and mote knives to the cylinder under casing, so that they are all set in combination, and an alteration of the position of the licker-in leads to a readjustment of all its attachments. The three gauges mentioned in paragraph 132 are combined, and the casings set sufficiently far from the cylinder to permit of the introduction of the three gauges. That is to say, the space left is ·031 of an inch, which is found to be generally ample, but this is subject to the remarks previously made.

Fig. 69.J.N.

(145) In addition to the necessity for under casings, covers are required for the licker-in, cylinder, and doffer. As the circles described by the teeth on these three parts approach each other, as shown in Fig. 46, it is desirable that the covers used should go as near to the point of approach as possible. If any space is left the fly and dirt speedily fills it, and from time to time drops upon the doffer, causing a thick place in the sliver. The arrangement used by Messrs. Dobson and Barlow is shown in Fig. 72, and it will be seen that the cover goes close down into the space left between the cylinder and doffer, and effectually prevents any accumulation of dirt. The cover is in three parts, and is hinged so as to permit of the surface of either cylinder H or doffer F being stripped or ground as desired. Setting arrangements are provided, by which the cover can be maintained in an accurate position during the whole period of work, although it may be necessary to set the doffer in towards the cylinder. The shape of the centre portion is specially designed to permit it to receive the strippings from the flats. Again referring to Fig. 69, it will be seen that similar arrangements are made for the licker-in and flats, the space between the flats and the cylinder wire being filled as shown, as is also the space between the licker-in and cylinder. The cover F over the cylinder and licker-in can be set up as desired, as can also the filling piece L below. All the covers are arranged to fit closely to the bend at the edges, so that there cannot be any blowing out at the side of the cylinder.

Fig. 72.J.N.

(146) The driving of the cylinder is obtained from the line shaft by means of a fast pulley fixed on the cylinder shaft, a loose pulley adjoining it to facilitate stoppage. The licker-in is usually driven from the cylinder by a crossed strap, and the doffer from the licker-in by a similar strap, which passes over a pulley mounted on a stud fixed in a lever. The pulley has a pinion on its boss, which engages with the doffer wheel U, and so drives it. The pinion, or “barrow-wheel,” can thus be easily thrown out of gear, as desired. The feed-roller is driven by a side shaft from the doffer shaft, placed on the other side of the machine to the main driving and the doffer comb by a cord passing over a grooved pulley on the cylinder shaft. The calender rollers are driven from the doffer, and the coiler shaft from the spindle of the calender roller.

(147) The pedestal is constructed with an extra long bearing, the shaft being 3¹/₂ inches diameter and the bearing 7 inches long. The bush lining the pedestal is usually made of phosphor bronze, or some equally good material, in order to resist wear. It was pointed out in paragraph 119 that it is essential that the position of the centre of the cylinder shall be continually maintained, and it is therefore desirable to guard against its movement. If it is considered, it will be understood that the centrifugal action set up by the rotation of so heavy a body as a carding engine cylinder will cause it to endeavour to roll forward, and thus induce wear in the front of the cylinder bearing. This is aided by the pull of the strap, which is usually towards the front. The provision of some ready means by which the wear can be taken up and the position of the cylinder centre restored, is, therefore, of great service. It is not practicable to employ the conical bearings often used in other classes of machines, as the wear not being equal, a tightening of the bearing would not take it up.

(148) Messrs. Howard and Bullough adopt a plan by which the pedestal is fitted upon two wedges, or inclined metallic surfaces, placed one above the other. By setting one or both of these wedges in either direction, the pedestal is so adjusted that the cylinder centre can be moved either laterally, vertically, or angularly, as is required. Another plan, adopted by Messrs. Ashworth Bros., consists of the formation on the pedestal of three projections, or claws. The inner surface of these is bored concentrically with the pedestal bearing, so that when the cylinder is in its true position, a cylindrical template, bored to correspond with the diameter of the shaft, and turned on its outer surface the same size as that to which the projections are bored, can be easily pushed up to the face of the pedestal. Unless this can be done the cylinder is not concentric, and the adjustment of the bearing must be made accordingly. Messrs. Dobson and Barlow employ the device shown in Fig. 73, which consists of two eccentric bushes, X Y, surrounding the bush in which the shaft Z revolves. The eccentricity of each of the bushes is equal, and thus by moving one or both the position of the centre of the cylinder can be adjusted at will, either laterally, vertically, or angularly. To facilitate the adjustment, two screwed rods, U V, are attached respectively to lugs formed on the bushes X Y, and pass through brackets formed on the pedestal. By means of nuts placed at each side of the brackets the adjustment of the position of the eccentric bushes can be made at will.

(149) In order to diminish the evil effects of the pull of the strap, as mentioned in paragraph 119, the plan shown in Fig. 74 has been adopted by Messrs. Ashworth Bros. Instead of keying the fast pulley on the shaft, it revolves on a hollow boss C, which has a flange or plate attached to the pedestal F. The pull of the strap on the fast pulley A is therefore taken by the bush or hollow boss C, and not by the shaft. Fixed on the shaft is a coupler D, which is formed with two arms engaging with corresponding recesses in the centre of the boss of the pulley A, something similar to the ordinary driver used in turning. By these means the shaft is rotated without there being any pull upon it, and one fruitful source of forward wear is thus removed.

(150) The three points which it is necessary to bear in mind in regard to carding were indicated at the opening of this chapter. These were the cleansing, parallelisation, and attenuation of the lap, and a few words may be said about each in that order. The velocity with which the teeth of the licker-in strike the end of the lap causes the fibres to be effectually loosened, and shakes a good many of the motes out of the cotton. Others are left on the surface of the fibres held by the licker-in wire, and are removed by the mote-knives as described, while some enter the spaces of the licker-in covering, from which they are easily thrown. On passing to the cylinder, the short fibres are largely thrown off as fly, or when they are subjected to the combing action of the wire teeth on the rollers or flats they are removed, and become fixed in the spaces in the covering. The “neps” are in a similar way taken out of the fleece, and from this cause periodical stripping is desirable of both rollers and flats. By reason of the centrifugal action of the cylinder many short and nepped fibres are driven into the roller or flat wire, but a certain proportion also remain in the cylinder wire, which also requires stripping periodically.

(151) It is somewhat difficult to define the exact action of the wire points by which the crossed and tangled fibres in the lap are laid in approximately parallel order. There is little doubt, however, that the speed of the cylinder plays an important part. The fibres are by the action of centrifugal force thrown out, so that, while held at one end by the cylinder wires, they are rapidly drawn through the wires on the rollers or flats. If the grip of the fibre is slight, as in the case of a short fibre, it will be removed, but, if it is sufficient to hold, it follows that the fibre would be combed by the superimposed wire teeth. In this way the thickness of the fleece on the cylinder plays an important part in determining the amount of parallelisation the fibre receives. If this is thin, each fibre, in all probability, receives its due treatment, while, if it is thick, the fibres are dragged—so to speak—through the wire teeth above, and would be likely to be injured, besides which their arrangement is more difficult. For this reason, the lighter the carding—that is, the less the weight of cotton passing at a given time—the better, provided that this is not pushed so far as to be uneconomical. It has been pointed out that the setting of the flats in the self-stripper lends itself peculiarly to effective combing, as the pitch of the wire teeth and the distance between them and the cylinder teeth can be gradually made finer. In the case of the roller card the fibres are lifted off the cylinder, and, if well held, would be drawn straight in the process. In their transfer by the clearer to the cylinder the fibres are further dealt with, but it is problematical whether the alternate raising and return of the fibres from and to the cylinder, results in a parallel order being obtained equal to that by other machines. A good result arises from the use of a roller card as a breaker, and a self-stripper as a finisher card, and this arrangement is often adopted.

Fig. 73.J.N.

Fig. 74.J.N.

(152) The attenuation of the lap is one of the most important functions of the carding engine, because it is the first stage in the formation of a thread, by reason of the easy condensation or collection of the thin film into a strand. Assuming that the feed roller is 2¹/₂ inches in diameter and makes one revolution per minute, it will deliver 7·854 inches of lap. The licker-in being 8 inches in diameter, and revolving at a speed of 400 per minute, is capable of delivering 10053·12 inches. As it cannot get this length of lap, it follows that in its revolution the teeth remove a small portion of the cotton continuously, and thus produce a layer or fleece, which is increased in length and diminished in thickness. The ratio of this increase is that just given, being equal to 1,280:1. When the cotton is transferred to the cylinder a further reduction takes place. The cylinder, being 50 inches in diameter and revolving, say, 150 times per minute, is capable of delivering 23,562 inches of cotton, or 2·34 times as much as the licker-in. Thus, up to this stage, the lap is elongated 3,000 times, as compared to its thickness when passing the feed roller. If the lap is ¹/₄₀ inch thick the fleece on the cylinder, if spread out, will only be ¹/₁₂₀₀₀₀ inch thick. It will be easily seen by a reference to the sizes of the cotton fibres that this is much thinner than the smallest diameter of individual fibres, and it follows, therefore, that if there was only this amount of cotton on the cylinder there would be many bare places. As the work of carding proceeds the cylinder becomes charged with cotton, but is never so full that the fibres cannot be carded thoroughly and individually, unless the rate of feed is excessive or largely increased. As the fleece is deposited on the doffer the reverse process occurs, as the doffer, being 24 inches diameter and revolving only 12 times per minute, would only deliver 904·78 inches, or ¹/₂₅th of that of the cylinder. Thus, the sliver, when collected, would be about ¹/₁₁₅th of the thickness of the lap. These figures are, of course, only approximations. As was previously shown in paragraph 112, the rollers and clearers in a roller card revolve at a much slower speed than the cylinder. The cotton is therefore subjected to a series of condensations and attenuations as it passes round the machine.

(153) An enlarged view of the sliver as it leaves the doffer is given in Fig. 75, and shows that the fibres, although not in parallel order, are arranged so that a slight additional pull is sufficient to straighten them. This the sliver receives partially between the calender rollers and the coiler, but it is in the drawing frame that the greatest effect is obtained. The draught there exercised speedily causes parallel order to be attained in the sliver, which is in good condition for this action. The draught in a carding engine takes place between the feed rollers and licker-in, between the licker-in and cylinder, and between the calender rollers and coiler, the total draught being reckoned between the feed roller and coiler. The question as to the speed of the doffer turns upon the amount of condensation required and the weight it is desired to get through the machine. There is a distinct relation between the speed of the cylinder and that of the doffer, but it has never yet been practically fixed, and carders vary in their speeds considerably.

Fig. 75.

Fig. 70.

Fig. 71.

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