(226) In Fig. [128] a front view of a slubbing frame, and in Fig. [134] a back view of a roving frame, as made by Mr. John Mason, are shown. The sliver is brought from the drawing frame in the cans in which it is coiled, these being placed at the back of the slubbing machine. It is drawn from the cams over a guide roller, and is then conducted to the drawing rollers. After being treated in the slubbing frame the bobbins produced are placed upon wooden pegs, pointed at both ends, which are sustained in bearings in the light frame S shown in Fig. [134], this being known as a “creel.” The bobbins are borne in an almost vertical position, and revolve easily as the slubbing is being drawn off. There may be two or three rows placed in the creel, which is described as a one, two, or three height creel accordingly. In either case the material is conducted as in the slubbing frame to the drawing rollers. Of these there are usually three, but sometimes four lines, their construction being generally similar to those used in the drawing frame, the back set of top rollers being ordinarily heavier than the front ones. The rollers are carried in brass bearings, fixed to the roller beam, and are weighted as in the drawing frame. Top clearers are fitted above the rollers, which are quite covered by polished cast-iron covers. The bottom rollers are kept clean by the aid of a revolving clearer kept closely pressed against them by a two-armed spring, the ends of the arms being grooved to form bearings for the axes of the clearer roller. The “under clearer” spring is attached to the roller beam, and is usually made of flat steel, stamped out of a sheet. A better form, made from round bright wire, has been recently introduced by Mr. C. H. Pugh, of Birmingham, which has the great merits of catching less fly and being more easily cleaned. As was said in the previous chapter, the absolute cleanliness of the rollers is essential, as otherwise the sliver will adhere to them—this being known as “licking”—and will be wrapped round them, thus producing “roller laps.” The drawing action having been fully described in the preceding chapter, it is not necessary to go over the same ground. The diameter of the front rollers in the slubbing frame are about 11⁄4 inch, and in the roving frame 11⁄8 inch. The weights are heavier in the slubbing frame, and in all the series the back rollers are more lightly weighted than the front. Thus the weights used for the front, middle, and back lines in the slubbing frame are respectively 18, 14, and 10lbs; in the intermediate frame 14, 10, and 8lbs.; and in the roving frame (with single bossed rollers) 10, 8, and 6lbs; and (with double bossed rollers) 18, 14, and 12lbs.
(227) The mode of constructing the spindles A, is illustrated in sectional elevation in Fig. [129]. The spindles are made from round steel from 9⁄16 inch to 7⁄8 inch diameter, and are arranged in two rows, one behind the other, with their centres alternating thus _ -_ - _. This arrangement permits of more spindles being fitted into the space at liberty. Usually the distance from centre to centre of adjoining spindles denotes the “gauge” of a machine, but in the series of machines now being dealt with, the peculiar setting of the spindles prevents this. The “gauge” in this case is denoted by the number of spindles in a defined number of lineal inches. Thus, to take an illustration from actual practice, a slubbing frame may have 4 spindles in 171⁄2 inches, that being its gauge; an intermediate, 6 in 191⁄2 inches; or a roving frame 8 in 201⁄2 inches. The spindles are accurately ground so as to be quite round, and vary in length from 28 to 42 inches. At the “foot” the diameter of the spindle is reduced, and the extreme lower end or “toe” is conical, being borne by a brass footstep fixed in a longitudinal rail. Immediately below the bobbin is an upper bearing or bolster, fixed in a similar rail. On the top of the spindle a flyer B is placed, this being of the shape shown, and constructed of steel. The legs are oval in section, and may be either tubular or solid, being made as light as possible. At the centre of the bridge connecting the legs is a circular double boss C, which is bored throughout, the hole so formed being carefully rounded and polished at its upper orifice. At a point near the top a hole is bored penetrating to that in C, and being also well rounded and polished. The lower portion of C constitutes a socket, into which the upper end of the spindle fits, the latter passing above the point at which the bridge is attached to the boss. A slot is cut across the upper end of the spindle, and a round pin, engaging with the slot, is fixed in the socket of the flyer, which is thus positively driven.
Fig. 128.
WATKINSON ENG.
Fig. 129.J.N.
(228) Attached to one or both legs of the flyer are two snugs or projections D D1 acting as bearings for pressure fingers or “pressers” E. The latter are round rods, hooked at their upper ends and bent at right angles at their lower ends. The hooked portion can be dropped into a socket in the upper snug D, and the presser thus oscillates freely on the centre of the bearings D D1. The inner end of the finger E is flattened and curved so as to correspond with the surface of the bobbin F, being formed with a guide-eye, as shown. It is made of such a length as always to press upon the surface of the bobbin during the rotation of the flyer, which it is caused to do by the centripetal action set up by the latter. The amount of pressure exerted depends entirely on the rate of the revolution of the flyer, and the practical effect is that the roving is more tightly wound on the body than it would otherwise be. It was at one time customary to use two pressers with each flyer, but it is more generally the practice now to employ one only. Great care is taken to balance the flyer, and, when single pressers are used, one leg is made solid and the other tubular, the presser being fitted to the latter. The sliver, after leaving the rollers, is passed through the upper part of the boss C, emerging by the small hole referred to, being then wrapped round the presser two or three times, and finally conducted through the guide-eye in the finger to the bobbin F. Both the inner and outer surface of the flyer must be absolutely smooth, as otherwise it catches the fibre and forms “fly.” For this reason, steel, as a constructive material, has entirely superseded the fine iron formerly used.
(229) The spindle is borne, as was shown, by a bolster and footstep. In order to give steadiness and reduce friction it is the practice to fit in the former a collar or tubular bearing. This is either “short” or “long.” Formerly short collars were the rule, these merely acting as a somewhat longer bearing, the bobbin in its vertical movement sliding upon the spindle. Mr. John Mason then introduced the “long” collar which is shown in Fig. [128]. The collar I is of sufficient length to extend from the bolster, bearing upwards through the bobbin to a point within the flyer. It is recessed internally, so as not to bear the entire length, but simply to be in contact with the spindle at two points. The latter is thus sustained high up, in addition to being borne, as usual, at the two lower points. The effect is that a much less amount of vibration is set up, and the flyer revolves with greater steadiness. This has an important bearing upon the operation, as it diminishes considerably the risk of breakage.
(230) Another method which, in many respects, is superior to any other, is that shown in Figs. [130] and [131] in vertical section and elevation. This is the plan previously adopted by Messrs. William Higgins and Sons, and now made by Messrs. Crighton and Sons, and Shepherd and Ayrton. In this case the spindle A is carried in a long tube I, which extends downwards until it is formed, as shown, into a footstep for the spindle toe. In short, the spindle is sustained in a kind of tubular cradle, being to a certain extent entirely free of the fixed bearing rails J K. To these the tube I is attached by swivel joints, so arranged that they are universal, thus allowing the spindle A and flyer B to adjust themselves as required to compensate for any unevenness of balance which may exist in the bobbins or flyers. The tube I is recessed for a certain part of its length, so as to form an oil chamber and reduce the friction set up during work. The advantages arising from this arrangement are that, even when the spindle is running at high velocities, any untrueness in the balance of the spindle merely causes it to find its true centre of gravity, and thus avoid vibration or wear. Spindles constructed in this manner can be worked for many years without showing any wear which is at all detrimental, and on this account higher velocities are attainable with ease than can be reached with the ordinary methods of construction.
(231) The spindles are positively driven as shown in Fig. [130], by means of bevel wheels fastened near the foot. In the arrangement shown in these drawings the spindle pinions F are formed with square holes, into which the spindles, similarly shaped, are fitted. This allows the spindle to be easily lifted out when required for examination. Usually the pinions F are fastened to the spindle by means of a set screw. In either case they engage with a bevel wheel G fastened on a shaft H, carried in brackets fixed to the framing, and extending longitudinally along the frame. The spindles being set zig-zag, as described, there are two lines of them, and consequently there must be two shafts H to drive them, and in order to distinguish between the two, they are supposed to be shown in position in Fig. [131], and the back wheels are marked F1 G1. The shafts H are geared so as to revolve at the same velocity, but in opposite directions, and, as it is imperative that the spindles shall revolve in the same direction, this is attained by gearing the pinions F F1 on different sides of the centres of the wheels G G1, as clearly shown. To enable this to be done, the teeth of the wheels are cut at a special angle or “skew” to suit.