(320) Referring again to Fig. [161], the ends of the copping rails have pins fixed in them, on which are anti-friction bowls, which run upon the edges of the copping plates. The latter are duplicated, so as to sustain the rail at each side, and thus maintain its vertical position. At one side of one of the plates Y is an ear S1, which is threaded to correspond with a square threaded screw S passing through a fixed bracket fastened to the floor. In this way the screw S is free to revolve, but cannot make any longitudinal movement. On the end of the screw S a ratchet wheel is fixed with which a pawl S2 engages, which is oscillated so as to move the wheel one tooth at convenient times. The speed of the revolution of the screw varies according to the counts being spun, the elevation of the point of locking being more quickly effected when coarse yarns are being made than when the finer varieties are produced. Whatever may be the velocity at which this elevation is accelerated, the profile of the copping plates is such that the inner end of the copping rail P is lowered at a more rapid rate during the formation of the cop bottom than at a subsequent stage. The reason of this will be easily comprehended, if the description of the mode of building the latter be borne in mind. It was then shown that the traverse of the winding faller rapidly increased in extent until the full length of the cop bottom was built. It, therefore, follows that the descent of the locking lever must be largely increased at this period at a quick rate, in order to produce the result indicated. When the outer end of the copping rail begins to descend at a rate which more nearly corresponds to that of the inner end, it gradually approaches to the horizontal, and the vertical motion of the slide, locking lever, and faller is proportionately limited.
(321) The regulation of the winding faller as just described was the one which was usual until recent years. It has been found necessary, however, to obtain a more accurate regulation, so as to ensure that the faller wire shall be in its correct position when locking occurs, especially during the period between the beginning of a cop and the attainment of its full diameter. It is now customary to attach to the front end of the copping rail a loose plate Q, which is hinged at one end to the rail, and which carries at its outer extremity a pin and bowl resting upon a third inclined plate Z. By varying the profile of the plate Z, the regulation of the faller during the early part of its traverse can be accurately made and the proper position of the wire ensured. As a glance at the illustration will show, the upper edge of the copping rail is not straight, but is shaped so as to give a variable speed to the slide L in its vertical movement. The proper shaping of the copping rail gave rise to some difficulty, and it will be seen that the loose copping rail Q is shaped so as to produce the proper effect, while being much more easily adjusted.
Fig. 161.J.N.
(322) The actual operation of this mechanism is as follows: When the carriage is at its outermost point, and the winding faller is locked, the wire is, as previously mentioned, a little below the nose of the cop. As the inward run proceeds, the bowl first runs up the loose incline, thus raising the locking lever and depressing the winding faller wire. The distance, from the extreme outward point reached by the bowl L1 and that where the loose rail Q is hinged and the downward inclination of the copping rail begins, is so short that the initial depression of the winding faller is very rapid. This produces the coarsely pitched coils referred to in paragraph 317, and illustrated in Fig. [164]. By the time the bowl L1 is at its highest point the winding faller wire is opposite the base of the upper cone. The subsequent downward inclination of the copping rail is much less acute, and the consequent descent of the faller locking lever less rapid. As a result the upward traverse of the winding faller wire is made more slowly, and the yarn is wound in more finely pitched spirals. It only remains to be said, in connection with this part of the subject, that owing to the shape of the copping plates their inward movement is accompanied by a gradual fall of the copping rail, and, consequently, the locking point of the faller lever is relatively elevated. In other words, the traverse of the locking lever prior to locking is gradually lessened as the trail lever slide L is lowered, and this is equivalent to an elevation of the winding faller lever and its locking point or shoulder K. This causes the depression of the winding faller wire prior to locking to be gradually diminished, so that there is an elevation of its initial point.
(323) The method of obtaining the traverse of the winding faller having been described, the equally important points relating to the mode of rotating the spindle during winding require to be dealt with. A little thought will show that so long as the surface upon which the yarn is wound remains small the spindles must revolve at a more rapid rate than when the surface is enlarged. As the extreme diameter of the cop bottom is enlarged the conditions of successful winding are continually changing. At the commencement of the cop the yarn is wound upon what is practically a parallel surface with a diameter of 5⁄16 inch and a circumference of ·98 inch. This implies that to wind the 63 inches of yarn 64·3 revolutions are required, these being made during the run up of the carriage. But as the diameter of the cop is enlarged the circumference of the conical surface becomes a variable one, and owing to its enlargement the number of revolutions required to wind the same length of yarn is fewer. This is quite clear and needs no demonstration. Thus when the cop bottom is formed the extreme range of variation is reached, and it follows that in the interval between the commencement of winding and the formation of the cop bottom each stretch must be accompanied by a diminution of the velocity of the spindle proportionate to the increase of diameter. In addition to this it is necessary to take into consideration the varying diameter of the conical surface on which winding takes place, which necessitates a greater terminal than initial velocity of the spindle.
Figs. 163 and 164.J.N.
(324) A further point requires elucidation. If the spindle blade were parallel, the number of revolutions necessary to wind the 63 inches of yarn properly, when the cop bottom is formed, being fixed, no further alteration would be necessary. But these conditions do not exist, and the nose of the cop is wound upon a continually diminishing diameter. It is of the utmost importance that the yarn is wound tightly at the nose during the whole of the building of the cop. The rate of the vertical traverse being practically uniform, unless an acceleration of the spindle velocity occurred, there would be slack winding during the latter part of the building of the cop. This would produce a sponginess of the nose, which, when the yarn was drawn off in the subsequent process of winding, as shown by the arrow in Fig. [164], would result in several rings or coils being pulled out in an entangled condition, thus producing waste. Technically the cop would be said to be “halched.” Illustrating this part of the subject by figures, if the diameter of the spindle at the point B, Fig. [163], be assumed to be 1⁄4 inch, its circumference would be ·7854 inch; while if the diameter at H be assumed to be 1⁄8 inch, the circumference would be only ·3927 inch. To wind, say, 10 inches of yarn in each case, would require about 12 and 25 revolutions of the spindle respectively. It is therefore clear that, if the same length is to be wound with equal tension upon the nose of the cop throughout the whole process of building, there must be a gradual acceleration of the terminal velocity of the spindle. Although this is only slight at first it is required at an earlier point as the cop is formed, and becomes of increasing importance.