988 



COTTON- SPINNING 



lx>bl>in will be understood by-and-bye. Upon the top of the spindles, a wire fork. 

 called a fly or flyer, t, k, is made fast by a left-hand screw, and has one of its forks 



turned round at the end into a little ring. 

 The branch of the flyer at f is tubular, to 

 allow the thread to pass through, and to 

 escape by a little hole at its side, in order 

 to reach the eyelet at the end of that fork. 

 From this eyelet i, it proceeds directly to 

 the bobbin. By the revolution of the 

 spindle, the twisting of the portion of 

 thread between the front roller d, and the 

 nozzle/, is effected. The winding-on takes 

 place in the following way : -Since the 

 bobbin has no other connection with the 

 spindle than that of the thread, it would 

 but for it remain entirely motionless, rela- 

 tively to the spindle. But the bobbin is 

 pulled after it by the thread, so that it 

 must follow the rotation of the spindle 

 and fly. When we consider that the thread 

 is pinched by the front roller d, and is 

 thereby kept fully upon the stretch, we 

 perceive that the rotation of the bobbin 

 must be the result. Suppose now the ten- 

 sion to be suspended for an instant, while 

 the rollers d deliver, for example, one inch of yarn. The weight of the bobbin, and 

 its friction upon the copping beam I, will, under this circumstance, cause the bobbin 

 to hang back in a state of rest, till the inch of yarn be wound on by the whirling of 

 the fly , and the former tension be restored. The delivery of the yarn by the drawing 

 rollers, however, does not take place, inch after inch, by starts, but at a certain con- 

 tinuous rate ; whence results a continuous retardation or loitering, so to speak, of the 

 bobbins behind the spindles, just to such an extent as to secure the winding of the 

 yarn upon the bobbin as fast as it is spun. 



This process in spinning is essentially the same as what occurs in the fine bobbin 

 and fly frame, but is here simplified, as the retardation regulates itself according to 

 the diameter of the bobbin by the drag of the thread. In the fly frame the employment 

 of this tension is impossible, because the roving has too little cohesion to bear the 

 strain ; and hence it is necessary to give the bobbins that independent movement of 

 rotation which so complicates this machine. 



The up-and-down motion of the bobbins along the spindles, which is required for 

 the equal distribution of the yarn, and must have the same range as the length of the 

 bobbin barrels, is performed by the following mechanism : Every copping rail /, is 

 made fast to a bar m, and this, which slides in a vertical groove or slot at the end of 

 the frame, is connected by a rod n, with an equal-armed, moveable lever o. The rod 

 p carries a weight r, suspended from this lever ; another rod q, connects the great 

 lever o, with a smaller one s, t, upon which a heart-shaped disc or pulley u, works 

 from below at t. By the rotation of the disc u, the arm t, being pressed constantly 

 down upon it by the reaction, the weight r must alternately rise and fall ; and thus 

 the copping rail / must obviously move with the bobbins h up and down ; the bobbins 

 upon one side of the frame rising, as those upon the other sink. Strictly considered, 

 this copping motion should become slower as the winding-on proceeds, as in the fly- 

 roving frame ; but, on account of the smallness of the finished thread, this construc- 

 tion, which would render the machine complicated, is without inconvenience neglected, 

 with the result merely that the coils of the yarn are successively more sparsely laid 

 on, as the diameter of the bobbin increases. The movement of the whole machine 

 proceeds from the shaft of a horizontal drum, which drives the spindles by means of 

 the endless bands x x. Each spindle is mounted with a small pulley or wharf w, at 

 its lower part, and a particular band, which goes round that wharf or whorl, and the 

 drum y. The bands are not drawn tense, but hang down in a somewhat slanting 

 direction, being kept distended only by their own weight. Thus every spindle, when 

 its thread breaks, can readily be stopped alone, by applying a slight pressure with the 

 hand or knee, the band meanwhile gliding loosely round the whorl. A more complete 

 view of the throstle frame is presented by fig. 579. 



Several modifications of the throstle have been attempted, but very few of any 

 importance have stood the test of experience, at least, in England. The Danforth 

 throstle, invented in 1829, had for its main object to increase the speed of the spindles, 

 and so to enlarge the productive capacity of the machine. It failed, however, amongst 



