306 MR. J. C. DYER ON 



been regulated mostly by the " trial and error " method, 

 rather than by any reliable self-adjusting movements, the 

 discovery of a very simple train of movements for maintain- 

 ing the differential rotations required in the bobbin and 

 fly frame will at once be recognized as an invention of a 

 high order in mechanical science. From the proper 

 limits of this paper, these notices must be confined to the 

 main features of the delicate movements and the general 

 operations of the machinery in question; so that those 

 wishing for the minute description of the different motions 

 above-mentioned must consult the drawings and specifica- 

 tions of them given in the patents, as before stated*. 



* The movements are as follows : — 



a. Rollers, 300 turns per minute. 



b. Rovings, 33 yards per minute. 



c. Flyers, 3300 turns per minute. 



d. Twist, 100 turns per foot=8-i turns per inch, 

 c. Bobbins, 300 turns per minute. 



Taking the front rollers and the bobbins to be of the same diameters at 

 first, then by these proportions t^e rovings will be wound upon the bobbins 

 without strain or slackness. But the speed of the rollers must be altered to 

 suit the drawing to the different kinds of cotton, and then that of twist to 

 the lengths delivered. Again, the speed of the bobbins must be changed 

 as their size and shape alter by the rovings wound upon them. 



Now the problem is to make all the motions relatively the same as 

 above, when the changes take place to meet the conditions stated. The 

 following are the visible operations of the roving-frame : — A strap descends 

 from the driving-pulley, and works one fast and loose pulleys upon an axis 

 fixed on one end of the frame. This axis is geared by changeable wheels 

 and pinions to drive the rollers on the beams ; and from the same axis, 

 through proper wheels, pulleys, and bands, are driven the flyers and spindles 

 for giving the twist, and by another train of gearing the bobbins for taking 

 up the rovings. The length of the roving delivered depending on the speed 

 of the front rollers, all changes of these, of course, require corresponding 

 changes in the speeds of the flyers and bobbins. The continually varying 

 speeds of the latter are obtained through the action of traversing straps, 

 working over reversed cone-pulleys. These straps traverse endwise on the 

 cones, and the distances of such traverse motions are regulated by the 

 " notch-bars," viz. sliding plates so graduated that the division shall move 

 the straps just enough to give the equable surface-motions to the bobbins 

 through all their changes of size. These, then, comprise mostly what can be 

 seen of these frames, or what can be set forth in words without the aid of 

 drawings. 



