CERTAIN IMPROVEMENTS IN THRESHING MACHINES, AND IN STEAM BOILERS, ENGINES, AND OTHER APPARATUS FOR DRIVING THE SAME, WHICH APPARATUS IS APPLICABLE TO DRIVING OTHER MACHINERY
Year: 1848

page_text: LAALLS DI MUIT
ION
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
EXALL, of Reading, in the County of Berks, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Eighth day of March,
One thousand eight hundred and forty-eight, in the cleventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said William Exall, my exors, aditiors, and assigns, Her especial licence, full
power, sole privilege and authority, that I, the said William Exall, my exors,
exors,
admiors, and assigns, or such others as I, the said William Exall, my
adñiors, or assigns, should at any time agree with, and no others, from time to
time and at all times during the term of years therein expressed, should and
lawfully might make, use, exercise, and vend, within England, Wales, and the
Town of Berwick upon Tweed, an Invention of "CERTAIN IMPROVEMENTS IN
THRESHING MACHINES, AND IN STEAM BOILERS, ENGINES, AND OTHER APPARATUS FOR
DRIVING THE SAME, WHICH APPARATUS IS APPLICABLE TO DRIVING OTHER MACHINERY,"
partly communicated to me from abroad, and the remainder my own Inven-
tion; in which said Letters Patent is contained a proviso that I, the said
William Exall, shall cause a particular description of the nature of my said
Invention, and in what manner the same is to be performed, by an instrument
in writing under my hand and seal, to be inrolled in Her said Majesty's High
Court of Chancery within six calendar months next and immediately after the
date of the said in part recited Letters Patent, as in and by the same, reference
being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
William Exall, have ascertained and set forth the nature of my said Invention,
and the manner of carrying the same into effect, in and by the following descrip-
tion thereof, reference being had to the Drawings hereunto annexed, and to the
figures and letters marked thereon, observing that where different views of an
object are given, similar letters in each Figure denote the same parts in each.
My improvements in threshing machines relate to the mode of regulating the
distance of the concave or breasting from the axis of the drum, which carries
the beaters, and in the construction of the breasting, and in a moveable mouth
piece. These improved machines may be worked by the power of men, horses,
steam, or any other suitable power.
Figures 1 to 10 represent one of my improved hand threshing machines;
Figure 1 being a plan; Figure 2, a side elevation; Figure 3, an end eleva-
tion; and Figure 4, a horizontal section through the beater shaft, and Figures
5 to 10, detached parts. a, a, is the framing; b, the feed board; c, is the shaft
of the beater drum. I prefer to form the concave of bars of wrought iron,
case-hardened. Each of the bars composing the breasting is moveable in a
separate slot c¹, c', in the side frames, and the ends d, d, of the ribs or bars
composing the concave are formed cylindrical, and enter into grooves or
slots e, e, formed in two circular pieces f,f, (shown detached in Figure 6) placed
outside the frame one on each side, and moveable round the beater shaft upon
the guide pieces g, g.
These slots stand obliquely to the slots in the side frames, and form inclined
planes, upon which the ends of the concave rest; by turning the segments the
concave may be made to approach or recede from the beaters, according to the
direction in which the segments are turned. The segments are turned simul-
taneously by means of two toothed sectors h, h, which work into teeth on the
circumference of the segments, and are fixed on the end of the cross shaft i,
which is turned by the lever k. 1 is a spur wheel fixed on the driving shaft n,
the bearings of which are moveable in slots in the frame, as shewn in Figure 5,.
to allow larger or smaller pinions to be employed as may be required, and the
wheel gives motion to the pinion o fixed on the beater shaft.
When this driving wheel is required to have wooden teeth or cogs in lieu of
the common mortice wheel, I prefer a wheel having dovetailed grooves formed
across the circumference to receive the cogs, which are driven in sideways.
The teeth are to be formed of wood, previously compressed by a screw or other
convenient press to such dimensions as to admit of its being driven into the
groove by a very small force, but expanding afterwards from its natural
tendency it becomes very firmly fixed in the.groove. A portion of such a wheel

page_text: is shewn in Figure 9. Teeth formed of wood previously compressed may
wise be employed in mortice wheels of the ordinary construction.
like-
I would observe that if it is preferred that the breasting should stand con-
centric with the beaters, the slots should be formed in a radiating direction,
and the grooves in the segments should all form the same angle with the
circumference; but if the breasting is.to be excentric with the beaters, either
the slots in the frames should each have a different angle of inclination with
the periphery of the drum, or the grooves in the segments should each form
different angles with the circumference, or the angles both of the slots and of
the grooves may vary, or the ends of the breasting may be regulated by one or
more excentric slots in the said segments. In lieu of having each bar or rib
of the breasting to move in a separate slot, I sometimes employ the arrange-
ment shewn in Figure 10, which is an elevation (partly in section, to shew the
interior of the drum). a, a, a, are segments forming the breasting, each
segment being composed of a number of bars or ribs combined together; each
segment is attached to a separate guide piece b, b, b, which guide pieces are
moveable in grooves or guides formed in the side frames, and the guide pieces
have each a pin c, c, c, which enter slots d, d, d, in a circular segment e, move-
able round the beater shaft f. The circular segment is turned by a pinion g,
which works into teeth formed upon a portion of the outer edge of the circular
segment, and according to the direction in which it is turned the breasting
approaches or recedes from the beaters. h is a moveable mouth piece, com-
posed of iron or other material, one end of which is hinged to the move-
A similar
able breasting, and the other slides upon a bar or guide at i.
mouth picce is applied to the arrangement, shewn in Figures 1 to 8, and is
therein indicated by a red line marked x. In lieu of adjusting the concave by
means of two sets of slots, one set being in a fixed frame, and the other in a
moveable frame, as above described, two plates moveable round the axis of
the beaters with an eccentric groove in cach to receive the ends of the bars or
plates forming the concave may be employed, and the bars may be linked
together, one of them being hinged to the frame.
My improvements in steam engines consist, firstly, of a modification of that
description of engine known as Brunel's engine; secondly, of a method of
shifting the position of the eccentrics which work the valves, either for the
purpose of reversing the motion of the engine, or of altering the degree of
expansion; and, thirdly, in improvements in that description of rotatory engine
known as Hiero's engine. Figures 11 and 12 represent one of my improved
Brunel engines, designed to work a threshing machine on the first motion (if
requisite). Figure 11 is a side elevation partly in section, and Figure 12 an

page_text: end elevation on the line Z, Z, as a base line, and shewn partly in section.
a, a, are two cylinders, cast in one with the bed plate 6, and standing at an
angle with each other of about ninety degrees. c, c, are the side frames which
support the plummer blocks or bearings of the shafts, and which are on the top
of the cylinder. Each piston has two rods d, d, which pass through stuffing
boxes in the top of the cylinder, and are attached to a cranked or forked cross
head e, the central portion of which forms the pin on which the lower end of
the connecting rod works. A recess fis formed in the top of the cylinder to
allow the lower end of the connecting rod to descend below the top of the
cylinder on the descending stroke, with the view to obtain a longer connecting
rod, and a corresponding recess 9 is made in the pistons to allow the pistons to
nearly touch the top of the cylinder at the top of the stroke. One of tho
connecting rods h is connected by a clip i to the pin of the driving crank j;
but in order not to lengthen the crank pin the other connecting rod h¹ is con-
nected, not to the pin of the crank, but to a pin k carried by the clip i. The
driving shaft may be connected directly to the driving shaft of the threshing
machine by a universal joint. m is the slide valve worked by the excentric n,
and o is an expansion valve which slides on the back of the valve n, and is
worked by the eccentric p. Figures 13, 14, and 15 represent my method of
altering the position of excentrics, which work slide valves without stopping
the engine for that purpose. In the shaft (a) upon which the excentric (b) is
placed, a longitudinal groove (c) is formed to receive a toothed rack (d), which
gears into a spur pinion (e) contained in a cavity made transversely in the
shaft. On the opposite end of the axis f of the pinion which projects outside
tho 'shaft is cut a bevilled pinion g, which gears into a bevilled toothed arch,
formed upon the face of the excentric. If the rack be moved endwise it will
cause the pinions c and g to rotate, and the pinion g will cause the excentric
to turn upon the shaft backward or forward, according to the direction in
which the rack is moved. The motion of the rack may be produced in various
ways, but I prefer the following:-A pin i connects the rack with a hoop k,
which is moveable along the shaft; this hoop has a groove in its circum-
ference to receive a clip m, which carries a nut n, in which works a screw o,
which is turned by the handle p, the other end of the screw working in a
bearing attached to the side frame. The motion of the screw causes the
hoop to advance or recede along the shaft carrying with it the rack. If the
valve be a compound valve like that shewn in Figure 13, a separate rack with
pinions, &c., will be required for the expansion slide. Figures 16 and 17 repre-
sent my improvements on the rotatory steam engine commonly known as Hiero's
engine, and the mode in which I apply it to drive a threshing machine. The

page_text: improvements consist in certain arrangements for admitting the steam to the
arms and regulating its emission therefrom, and for reversing the motion of the
engine. Figure 16 is a section of the arms edgeways; and Figure 17 is a
section of the same at right angles to the former. The steam is admitted by
the steam pipe a into the steam chest (6), whence. it enters the hollow neck c
(which is surrounded by a collar of vulcanized india-rubber d, with two
metallic washers d', to prevent the escape of steam), and passes into the
arms e, e, which have each two apertures f¹, f", near their extremities for the
escape of the steam. The apertures in each arm are situated in the opposite edges
of the arm, but not facing cach other, but are placed in such position that both
may be closed at the same time by the valves g', g, or one may be closed and
another open. Tho valves are connected by springs h, h, to a rod i, which may
be moved endwise either by the crank k, which is connected by a link and
swivel m to the screw n, or by any other suitable means, and thus the aper-
tures f, f, for the escape of the steam in the one direction, or the aper-
ture f",f", for the escape of steam in the opposite direction, may be wholly or
partially open, or they may all be closed. The hollow neck is supported in
bearings at o, and the solid spindle p in a bearing at 7. The arrangement of
wheels shewn at r, r, is for the purpose of reducing the speed to that required
for driving the threshing machine, and s is the universal joint for connecting
the engine to the beater shaft. Figures 18 to 21 represent a portable boiler
upon my improved construction; Figure 18 being a front elevation; Figure 19,
à vertical section; Figure 20, an elevation of the boiler with the outer casing
and fire box removed; Figure 21, a horizontal section on the line z, z. a, α,
is a tube or cylinder forming the fire box; b is a concentric cylinder forming
the sides of the boiler; and c is a small tube rising from the roof of the fire
box through which the fuel is introduced, and fitted with a moveable cover c¹.
d is an annular plate, forming the bottom of the boiler; and c is an annular
plate forming the top of the steam chamber. ff, are a series of short tubes,
open at each end, and which are fixed into the fire box a and cylinder 6 in a
radiating position, and constitute fire tubes or short flues. 9 is the casing,
closed at bottom by the plate h, and at top by the plate i. The space j
between this casing and the boiler forms a flue into which the heated gases
and smoke from the fire arrive after passing through the tubes f, f. h is the
ash pit. The fire bars m, m, are supported below the bottom of the boiler
upon the cranked bars n, n, the surface of the fire bars being a little below the
bottom of the boiler, so as to leave a space all round the grate for the more
ready admission of air to the fuel. o is the ash pit door, and p the chimney.
In lieu of feeding the fire from the top, the fuel may be introduced through a

page_text: tube in the side, as indicated by the blue lines at q. Figures 22 to 24 repre-
sent an improved horse gear for driving a threshing machine; Figure 22 being
a vertical section; Figure 28, a plan; and Figure 24, a plan with the cover
removed. a is a cylinder, the upper rim of which is faced plane and turned
on the outer circumference; and 6 is a cover, having sockets to receive the
arms d, d, to which the cattle are yoked. The lower rim of the cover is like-
wise properly faced, and turned so as to allow the cover to turn truly and freely
upon the cylinder. Beneath the cover are suspended three toothed wheels e, e,
which gear into a toothed ring e' formed round the interior rim of the cylinder,
and also into a pinion f fixed upon the shaft g. A bevilled wheel h fixed upon
the lower end of the shaft gears into a bevilled pinion i fixed upon the lying
shaft j, which is connected by an universal joint k to the driving shaft of the
threshing machine. Upon turning the cover it will be seen that the wheels e, e,
cause the shaft g to revolve faster than the cover in the proportion of the
diameter of the toothed ring e¹ to the diameter of the pinion f, and that the
bevilled wheel g will impart an accelerated velocity to the lying shaft j. m is a
smaller roller to prevent the wheel h from rising. Figures 25 & 26, in com-
bination with Figures 22, 23, and 24, shew an arrangement of horse gearing for
driving (in addition to a thrashing machine) a corn mill situated immediately
over the driving shaft. a is the framing of the mill; b, a shaft, connected by
an universal joint to the lower shaft (g, Fig. 22), and carrying a wheel c, which
gearing into the pinions d, d, fixed upon the shafts e, e, drives the said shafts.
Upon the upper end of the shafts are fixed the wheels f, f, which gear into
the pinion g fixed upon the spindle of the running stone, and thus. drive the
stone with the required velocity. Figure 26 is a plan of the wheelwork, the
several wheels and pinions being denoted by the blue circles.
Having thus described my Invention, and the manner of carrying the same
into effect, I proceed to state my claims in respect thereof. I claim is,―
Firstly, the forming the breasting or concave of wrought iron bars, either
case-hardened or otherwise, and separated or detached so as to be susceptible
of a separate adjustment, this latter improvement being of course applicable
to cast or wrought iron bars or bars made of any suitable material.
Secondly, the mode of adjusting the concave (whether the bars be separate
or combined in groups or sets) by means of two sets of grooves or slots
crossing each other, one set being in a fixed frame, and the other in a moveable
frame, or by means of two moveable plates, having eccentric grooves, as herein-
before described, and which it will be seen may be effected by one single move-
ment of the hand. Also the moveable mouth piece attached to the upper part
of the breasting, as herein-before described.

page_text: Thirdly, the employment of two piston rods to each piston, in what are
called Brunel's engine, with a cranked cross head, and forming a recess in the
top of the cylinders and pistons, in order to admit of a greater descent to the
cranked cross head and connecting rod.
Fourthly, the mode of adjusting the eccentrics which work the valves or
slides of engines (without stopping the engines) by means of a rack acting
upon a pinion contained within the shaft, which gives motion to another pinion
that gears into a toothed ring or arc on the side of the eccentric, as herein-
before described.
Fifthly, in respect to "Hiero's engine," the introduction of the steam into
the arms through a hollow neck working in a steam chest,, and the collar of
prepared india-rubber, with the brass or other washers employed to make the
revolving joint steam-tight, the partial or total closing of the emission apertures,
and the reversal of the motion of the engines by means of valves or slides,
receiving motion through the hollow axis or neck of the engine.
Sixthly, the combination of a vertical cylindrical boiler and fire box, having
radiating horizontal flues, as herein-before described, with a flue that surrounds
the boiler, and is bounded by the external casting of the boiler, also the placing
the surface of the fire bars somewhat below the bottom of the boiler, for tho
admission of air to the fire on all sides, as herein-before described.
Seventhly, as respects my improved horse gearing for driving machinery,
the inclosing of the wheelwork within a casing (preferably of a cylindrical
form), which casing has fixed to the top thereof a toothed rack or ring, into
which one or more toothed wheels attached to the under side of a revolving
lever holder or cover to the casing work, and drive a pinion fixed upon an
upright central shaft, so as to cause the said shaft to revolve faster than the
lever holder or cover.
Eighthly, the application of compressed wood to the manufacture of teeth
of wheels, so that when such teeth are driven into the recesses or cavities of
the ring of the wheel, their subsequently expansion may retain them therein.
Lastly, the forming of dovetailed or other suitable shaped grooves, extend-
ing across the face of the wheel, to receive teeth of a suitable shape, formed of
wood previously compressed.
In witness whereof, I, the said William Exall, have hereunto set my
hand and seal, this Eighth day of September, in the year of our
Lord One thousand eight hundred and forty-eight.
WILLIAM (L.B.) EXALL.

page_text: AND BE IT REMEMBERED, that on the Eighth day of September, in the
year of our Lord 1848, the aforesaid William Exall, Esquire, came before
our said Lady the Queen in Her Chancery, and acknowledged the Specifi-
cation aforesaid, and all and everything therein contained and specified, in
form above written. And also the Specification aforesaid was stamped accord-
ing to the tenor of the Statute made for that purpose.