88 TECHNOLOGY. 
of rovings. It differs from the former in this, that it spins and winds simul- 
taneously : it is, however, used only for the coarser kinds of yarn. The 
yarn spun upon the two machines is very different ; that from the throstle 
frame is hard and wiry, while that from the mule frame is soft and woolly. 
The former is used for the warp of heavy goods, for the filling of coarse 
goods, and also for both warp and filling of fine goods. The object of the 
throstle frame is to extend the rovings into slender threads, and at the same 
time to twist them. It consists of two roller beams, each provided with the 
usual three-fold set of drawing rollers. The fluted rollers receive the roving 
from the spools, which are placed upon vertical skewers fixed in shelves in 
the middle of the frames, called creeds. A throstle frame has seldom less 
than 72 spindles. : 
Pl. 18, jig. 2, is a view of a portion of the front of Danforth’s throstle 
frame ; jig. ’7,an end view; pl. 17, jig. 24, is a section through the spinning 
parts of the machine, and jig. 22 a is a peculiar spindle for winding on cops. 
AB (pl. 18, jig. 2) are the usual fast and loose pulleys, the former making 
about 480 revolutions per minute. Next to the pulley, pn, and upon the 
same shaft, is a pinion which drives the cog-wheel, c; and a pinion, p, upon 
the same shaft with the latter, drives the wheels, ¢ @ (pl. 18, fig. 7), through 
the intermediate wheels, = and r. The wheels, ce, drive the drawing 
rollers, HH, on both sides of the machine. These drawing rollers are 
arranged as in the other machines already described, the upper ones being 
pressed upon the lower by weights, x (pl. 17, jig. 24). The fluted rollers 
are set in motion by wheels and run with different velocities, the front 
rollers making about 120 revolutions in a minute, the middle ones about 17, 
and the back rollers 12. Their relative velocities are capable of regulation 
by the change of the intermediate wheels. In this manner the roving, 1, is 
drawn out proportionally to the relative velocities of the front and back 
rollers. 
The twisting is effected as follows: @ (pl. 17, jig. 24) are the spindles 
secured to the rail, m, by a screw; 6 is asmall pulley, with a hollow axle, 
running freely on the spindle, a. The pulley, 6, is driven by a band from 
the drum, x ( pl. 18, jig. 2). The band runs first round two spindles on one 
side of the machine, and then round two upon the other side, and lastly 
round the tightening pulley, m, back to the drum. In this manner four 
pulleys are driven and four threads are spun. Upon the pulley, 0, and 
over the said tube, the bobbin is placed, on which the thread is wound 
after being twisted by the revolution of the pulley, 4. The winding is 
effected by a hollow cylinder fast to the immovable spindle. The thread is 
forced to pass below the lower edge of this cylinder to the bobbin, which is 
revolved by friction upon the pulley, 6, and winds up the thread as fast as 
it comes from the rollers. This winding up would be very imperfectly per- 
formed, were not an up and down motion imparted to either the bobbin or 
the cylinder, in order to fill the bobbin evenly. It has been found prefera- 
ble to give this up and down motion to the bobbin. The small whorls 
which carry the bobbins slide freely up and down the spindles, and rest 
upon a bar, f, called the copping rail, which is raised and lowered by means 
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