I I I A 
lp NR A A ES 
THRASHING 
admit of two rates of velocity,—one in which 
they make one revolution while the drum makes 
53, and another in which they make one while 
the drum makes 4; and these two velocities have 
been found sufficient for all cases. The best form 
of fluting for the feeding rollers is, for the upper 
one a concave flute, and for the under an angu- 
lar flute; and the most approved gearing for 
working them is two pairs of spur-pinions, on 
parallel spindles with a sliding clutch between 
the pairs of driving pinions. This pair of pin- 
ions has each a round eye which admits of their 
revolving loose on the spindle, when not fixed 
by the clutch. By attaching the clutch to the 
one or the other of the driving pinions, the mo- 
| tion of the rollers is instantly changed from 
quick to slow, or vice versa, without stopping the 
machine. The sliding clutch is carried round 
with the shaft by means of a feather fixed in the 
shaft or spindle, and is slid by means of a lever, 
the long end of which rests on a plate with three 
notches. To change the motion of the rollers, 
the end of the lever is moved from one extreme 
notch to the other extreme; and to stop the 
rollers, it is removed into the centre notch. The 
distance of the rollers from the beaters, like their 
velocity, depends very much on the state of the 
corn to be thrashed; but as a general rule, five- 
eighths of an inch may be considered as very 
good; yet a variable distance is best,—and one 
of the simplest contrivances for effecting this is 
to have the block in which the rollers run made 
separate from the frame of the thrashing ma- 
chine, and afterwards fixed to the parts of the 
frame by strong bolts with a head on one end, a 
fixed collar between the block and the post, and 
a screw on the other end working in a nut sunk 
into the post, so that by turning the head of the 
bolts, the distance may be varied at pleasure. 
The under roller has its centre at least four 
inches above the level of the centre of the drum, 
and neither rises nor falls; but the gudgeons of 
the upper roller work in a perpendicular fork, 
whereby they are at liberty to rise or fall as the 
feed varies. The best coupling for the spindles 
or shafts of feeding rollers is an oblong box of 
malleable iron, welded to the end of one part of 
the shaft, and receiving that of the other part.— 
The apron of the drum is made in the form of an 
arc of a circle, whose diameter is about six inches 
greater than that of the drum. The lower end 
is placed five-eighths of an inch from the rollers, 
and the upper about 34 inches above the beaters. 
The best position of the rakes, in relation to the 
drum, is when their centre is placed 10 inches 
above the centre of the drum, and the extreme 
points of the first rake 10 inches from the beat- 
ers. The length of the rakes ought not to be’ 
less than six inches more than the drum. The 
diameter of the first rake is 6 feet over the ex- 
treme points,—and of the second 5 feet; and 
both make 18 revolutions per minute. The 
simplest and most economical mode of commu- 
MACHINES. 
nicating motion from the moving power to the 
first rake, and from that to the second, is by a 
pitch-chain, arranged as shown in /%g. 1.—The 
fans of the winnowing-apparatus are 3 feet in 
diameter, and 21 inches broad; and the most 
effective velocity is 213 revolutions per minute. 
The simplest method of communicating motion 
from the thrashing machine to the fanners is by 
a rope from the drum passing over the leading 
pulleys a, and on to the pulley of the fan; and 
for the old shoe and riddle, may be substituted 
an endless web moving round two small rollers. 
This is placed underneath the hopper, and re- 
ceives motion by a belt from the spindle of the 
fanner; and receiving the grain as it drops from 
the hopper, conveys it regularly forward till it 
falls before the fans. The endless web moves at 
nearly one-fourth of the velocity of the fans, 
While it is less expensive, and more easily kept 
in repair than the shoe and riddle, it also an- 
swers better, as it presents the grain more equally 
to the action of the fans. The method of work- 
ing the second fanners is, in general, by a motion 
from the machine. But when a separate power 
can be obtained at no great expense, as may be 
easily done when water is the power employed, 
it would be advantageous to adopt it to drive 
both fanners, as the regularity of their motion, 
requisite for producing good work, would not 
then be interrupted by the irregularities of the 
machine.—The most economical mode of raising 
the grain from the first to the second fanners is 
by elevators; and these may consist of an end- 
less web, formed into a continued series of square 
or oblong boxes, with a belt on each edge of the 
web, revolving on two pairs of parallel pulleys; 
but though the sides and bottoms of the boxes 
are formed of the endless web, their ends are of 
wood. It is obvious that the length of the ele- 
vators depends on the height that the grain has 
to be raised; the width of the boxes is regulated 
by the mouth of the fanners’ spout; and their 
depth is about 24 inches. The velocity of the 
elevators is about 180 feet per minute; and the 
motion is communicated to them by the upper 
pulleys. The elevators for the ‘shorts’ are con- 
structed on the same principle, and of the same 
materials, only larger.—The screen is made of 
cast-iron, hoop-iron, or wood ; the spaces between 
the spars are squares, whose sides measure 14 
inch ; and the spars, when of cast-iron, are five-six- 
teenths of an inch thick, and half an inch deep, 
The screen would with decided advantage be 
extended under the drum; but this could be 
done only in barns of greater elevation than most 
at present possess. The length and breadth of 
the top of the hopper are regulated by the length 
and breadth of the screen, and the height of it 
by the elevation of the barn. The sloping of its 
sides should not, however, be less than 50°. 
The suitable dimensions of the lower barn for 
a thrashing-machine of two-horse power, are 27 
feet long, 16 broad, and 74 high; for one of four- 
