When the building of the cop commences, the above-mentioned nut stands at the bottom of the screw, at the centre of oscillation. On the extremity of this screw, is a bevel-wheel T', gearing into a similar wheel on the boss of a spiral wheel T', running nn a fixed stud. This spiral wheel gears into a second spiral wheel Ta, on the shaft T' ; on the same shaft, is fixed the spiral roller T'. At this point the bowl begins to descend the longer incline of the shaper, which allows the faller-wire gradually to rise, guiding the thread to the apex of the cone of the cop, as the spindle winds it on. For a short distance, at both ends of the shaft T', is cut a screw-thread, which passes through a fixed nut bearing the shaft up. As the latter turns round, the spiral miler is taken towards the back, which gives leas motion to the nut in the radial arm ; this continues till the bottom of the cop is completed, when the spiral roller passes out of range, and its action ceases.
By meane of this arrangement, when the yarn becomes too tight in winding on, the counter faller o is depressed ; a lever under the carriage, which is attached to the counter-faller by a chain, is lowered until it comes into contact with the spiral roller, to which it gives motion ; by this means, the screw in the radial arm is turned round, working the nut upwards, until the yaru is slacketted so much as to permit the counter faller to rise, and to disengage the lever from the spiral grooves in the roller.
When the winding of the yarn upon the spindle is completed, and the carriage arrives at the drawing rollers, the fallers are disengaged by the pendant bar striking a fixed stop in the frame, pushing it outwards, and disengaging it from the slide, when the fellers rise by the action of their springs. When the carriage has been put up, and has arrived within a few inches of the roller be,am, the faller-shaft comes into contact with the incline E', pressing doam the end of tho long beam lever E, and foroing the pendant bar, with its circular incline, away from the steel pin, which allows the catch-box D' to turn the cam-shaft rev. when it puts the strap upon the fast-pulley, and all the other motions into their original positions, where they are ready to recommence spinning.
The operation of this complex arrangement of shafts, wheels, levers, pulleys, ropes and springs, may be briefly recapitulated a,s follows :—The creel having been supplied with bobbins containing rovings, the ends of the latter are passed through small guide-wires, and between the three pairs of drawing-rollers c. The function of the back pair—that first taking hold of the roving—is simply to draw the latter from the bobbin. The motion of the middle pair is slightly quicker than the first, but only sufficiently so to keep the roving uniformly tense, in order that when delivered to the next, or front pair, running much more quickly, the " drawing," or attenuation of the roving may be equal throughout. Connection is then established between the attenuated rovings and the spindles. When the latter are bare, as in a new mule, the spindle-driving motion is put into gear, and the attendants wind upon each spindle a short length of yarn from a cop held in the hand. This done, the drawing-roller motion is placed in gear, and the rollers soon present the attenuated roving in front, to which the threads on the spindles are then attached, by simply placing them in con tact with the untwisted roving. The different parts of the machine are next simultaneously
started, when the whole works in harmony together, the back rollers pulling the sliver from the bobbins, and passing it to the succeeding pairs, whose differential speeds attenuate it to the required degree of fineness. As it is delivered in front, the spindles, revolving at a rate of 6000-9000 nev. a minute, twist the hitherto loose fibres together, thus forming a thread. Whilst this is going on, the spindle-carriage is being drawn away from the rollers, at a pace very slightly exceeding the rate at which the roving is coming forth. This is called the " gain " of the carriage, its purpose being to eliminate all Irregularities in the fineness of the thread. Should a thick place in the roving come through the rollers, it would resist the efforts of the spindle to twist it ; and, if passed in this con dition, it would seriously deteriorate the quality of the yam, and impede subsequent operations. Ae, however, the twist, spreading itself over the level thread, gives firmness to this portion, the thick and untwisted part yield's to the draught of the spindle, and, as it approaches the tenuity of the remainder, it receives the twist, it had hitherto refused to take. The carriage, which is borne upon wheels, continues its outward progress, until it reaches the extremity of ite traverse, which is 54 in. from the roller beam, when the revolution of the epindlee ceases, the drawing rollers stop, and the backing-off commences. This process is the unwinding of the several turns of the yarn, extending from the top of the cop in process of formation to the summit of the spindle. As this proceeds, the faller-wire, which is placed over and guides the threads upon the cop, is depressed ; the counter faller at the same time rising, the elack unwound from the spindles is taken up, and tho threads are prevented from rnnning into snarls. When the backing-off is completed, the carriage com mences to run inwards—that is towards the roller-beam—the spindles winding on the yarn at a uniform rate, but by means of a varying speed in their revolution, as the faller is guiding the thread upon the larger or smaller diameter of the cone of the eop. Immediately the winding is finished, the depressed faller rises, the counter-faller is put down, and the former actions recom mence in the order described, and are repeated until the " set" ie completed—that is, the cope on each spindle are perfectly formed. In modern mules, when the set is finished, a etop-motion paralyzes every action of the machine, rendering it necessary to " doff," or strip the spindles, and to commence anew. Doffing is performed by the attendants raising the cops partially up the spindles, whilst the carriage is out ; then depressing the faller, so far ae to guide the threads upon the bare spindle below. A few turns are wound on, to fix the threads to the spindles for a new set, and then the cops are removed, being collected into cans or baskets, and subsequently delivered to the warehouse. The remainder of the " draw " or " stretch," as the length of spun yarn is called when the carriage is out, is then wound upon the spindlee by the carriage being run up to the roller beam. Work then commences anew.