IMPROVEMENTS IN THRASHING MACHINES
Year: 1861

page_text: LETTERS PATENT to Joseph Christian Davidson, of Yalding, in the
County of Kent, Farmer, for the Invention of "IMPROVEMENTS IN
THRASHING MACHINES."
Sealed the 18th March 1862, and dated the 20th September 1861.
PROVISIONAL SPECIFICATION left by the said Joseph Christian Davidson
at the Office of the Commissioners of Patents, with his Petition, on the.
20th September 1861..
"I, JOSEPH CHRISTIAN DAVIDSON, of Yalding, in the County of Kent, Farmer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
THRASHING MACHINES," to be as follows:-
My improvements relate to those parts of thrashing machines, known as
the "drum" and "concave." The drum as at present constructed consists of
a horizontal spindle, upon, which are fixed a series of radial arms or light iron
wheels, to the circumference of which are fixed a number of "beaters "formed
of wood or iron, or of both, and running parallel with the shaft or spindle.
The "concave consists of a wrought-iron cover, formed at a certain distance
round part of the circumference of the drum. The before-mentioned "beaters
of such drums, and the surface of the concave, have up to the present
time 'been made straight, that is to say, the drum is constructed throughout
of the same diameter. By this arrangement it has been found that the

page_text: machine is liable to choke, and further that if tho machino is overfed the drum
and its spindle are liable to get bent, thus destroying the effectiveness of the
machine; and, lastly, it is sometimes found that the corn does not become
thoroughly thrashed out.
Now the object of my present Invention is to remedy these defects, and
for this purpose I form the drum of different diameters, that is, the surface
of the same represented by the outer surface of the beaters is made either
convex, concave, or undulating in the direction of its axis, and-by preference I
form, the drum of larger diameter in the centre than at the ends. The "con-
" is formed to follow the curved surface of the drum, in the direction
parallel with the drum spindle, both drum and concave are otherwise constructed
similar to those of machines in present use. By the before-described manner
of constructing the drum, it is firstly rendered much stronger with even a less
amount of material than in the drums of ordinary construction, the curvature
of the surface acting as an arch, and more or less preventing the bending of
the drum spindle; this increased rigidity of the drum will also cause an increased
steadiness of the motion, and thereby effect a saving in the wear and tear of
the machine.
21
Secondly, the machine has less liability to choke with damp corn, or from
other causes, by reason of the different diameters of the drum, the straw being
better parted in consequence.
Thirdly, the corn is beat much cleaner than at present, on account of its
being beat in its passage round the drum, and being brought more in- contact
with the beating surfaces.
Fourthly, the machine requires less power to drive it, as the concave can be
placed at a greater distance from the drum, by which a less breakage of the
corn is effected.
SPECIFICATION in pursuance of the conditions of the 'Letters Patent, filed
by the said Joseph Christian Davidson in the Great Seal Patent
Office on the 19th March 1862:
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
CHRISTIAN DAVIDSON, of Yalding, in the County of Kent,, Farmer, send
greeting:
3
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters,
Patent, bearing date the Twentieth day of September, in the year of our Lord 8
One thousand eight hundred and sixty-one, in the twenty-fifth year of Her reign,

page_text: lid, for Herself, Her beirs and successors, give and grant unto me, the said;
Joseph Christian Davidson, Her special licence that I, the said Joseph
Christian Davidson, my executors, administrators, and assigns, or such others
as I, the said Joseph Christian Davidson, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great
Britain, and Ireland, the Channel Islands, and Isle of Man an Invention for,
"IMPROVEMENTS IN THRASHING. MACHINES," upon the condition (amongst others)
that I, the said Joseph Christian Davidson, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Joseph Christian Davidson, do hereby
declare, the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement thereof, reference being had to the accompanying
Drawing, and to the figures and letters marked thereon, that is to say:
My improvements relate to those parts of thrashing machines known as
the "drum" and the "concave." The drum as at present constructed
consists of a horizontal spindle, upon which are fixed a series of radial arms
or light iron wheels, to the circumference of which are fixed a number of
"beaters," formed of wood or iron, or of both, and running parallel with the
shaft or spindle. The concave consists of a wrought-iron cover, formed at
a certain distance round part of the circumference of the, drum. The before-
mentioned "beaters of such drums, and the surface of the "concave" have
hitherto been made straight, that is to say, the drum is constructed through-
out of the same diameter. By this arrangement it has been found that
the machine is liable to choke, and further that if the machine is overfed'
the drum and its spindle are liable to get bent, thus destroying the effective-
ness of the machine; and lastly, it is found that the corn does not become
thoroughly thrashed out.
Now the object of my present Invention is to remedy these defects; and
for this purpose I form the drum of different diameters, that is, the surface,
of the same, represented by the outer surface of the beaters, is made either
convex, concave, or undulating, that is, partly convex and partly concave in
the direction of its axis, and by preference I form the drum of a larger

page_text: diameter in the centre than at the ends. The concave is formed to follow'
the curved surface of the druin, the direction parallel with the-drum'
spindlo; both drum and concave are otherwise constructed, similar to those
of machines in present use. By the before-described manner of constructing
the drum, it is firstly rendered much stronger with even a less amount of
material than in the drums of ordinary construction, the curvature of the
surface acting as an arch, and more or less preventing the bending of the
drum spindle. This increased rigidity of the drum will also cause an increased
steadiness of the motion, and thereby effect a saving in the wear and tear of
the machine.
Secondly, the machine has less liability to choke with damp corn- or,
from other causes, the straw being better parted in consequence of the
difference of diameter of the middle and ends of the drum.
நய
Thirdly, the corn is thrashed much cleaner than at present, on account
of the straw being bent in its passage round the drum, and being brought
more in contact with the beating surfaces.
Fourthly, the machine requires less power to drive it, as the concavo
can be placed at a greater distance from the drum, by which a less breakage
of the corn is effected.
A
Fifthly, the drums can be constructed of greater widths than those at s
present in use, on account of their stronger form, and this is a great advan-
tage in thrashing crops of which the straw is unusually long..
But in order that my Invention may be more easily understood, and
readily carried into effect, I will now proceed to describe the best means am
acquainted with of performing the same.
Figures 1, 2, and 3 on the accompanying Drawing shew the construction of
my improved "drum" and concave which I employ by preference. Figure 1
shews an elevation of the drum; Figure 2 shews a longitudinal section,
through the "drum" and "concave"; and Figure 3 shows a transverse section
through the same. Similar letters of reference indicate similar parts in all the
Figures. A is the spindle of the drum; B, B, B', are the iron frames or
wheels, keyed fast upon the spindle, and upon which are fixed the beaters C, C, C.
The central wheel B' is made of a larger diameter than the end ones, by
which the beaters C, C, C, receive an arched form, as shewn. The beaters
may be provided with Goucher's patent grooved benter plates, as shewn, or
they may be formed in any other suitable manner. The concave D is formed
to follow the curve of the drum, as shewn. Figures 4, 5, and 6 shew another
mode of constructing my improved drum and concave. Figure 4 shews an
elevation of the drum; Figure 5 shews a longitudinal section; and Figure 6*

page_text: shews a transverse section. The beaters C of the drum are here curved inwards
so as to render the general surface of the drum concave, whilst the "concave
D is formed convex in the direction of the axis of the drum. The central
wheel B' of the drum is of a smaller diameter than the ends ones B, B. Figures
7, 8, and 9, shew another arrangement of my improved drum and concave.
Figure 7 shews an elevation, Figure 8 shows a longitudinal section, and
Figure 9 shews a transverse section of the same. The beaters C, C, are here
formed undulating, or partly convex and partly concave in the direction of the
axis of the drum, and the "concave " D is formed to follow the curve of the
In some cases I make the beaters of a straight piece of wood or other
suitable material, as shewn at C, C, Figure 10, and simply form the outer
surface c of the same, with the requisite amount of curvature. By this
arrangement the wheels or frames B, B, B, are all kept equal in diameter.
Having now described the nature of my Invention, and in what manner the
same is to be performed, I wish it to be understood that I do not limit myself
to the precise details, as shewn on the accompanying Drawing, as the sectional
form, the amount of curvature, and the number of the beaters, as also the
construction of the concave, may be varied without departing from the nature
of my Invention; but what I claim under the before in part recited Letters
Patent, is, the construction of thrashing machines in which the external
surface of the "beaters" of the drum are formed with a curvature in the
direction of the axis of the same, and in which the "concave" is made to
follow the curved surface of the drum in the direction of its axis, substantially
as herein-before described.
In witness whereof, I, the said Joseph Christian Davidson, have here-
unto set my hand and seal, this Fifteenth day of March, in the year of
our Lord One thousand eight hundred and sixty-two.
JOSEPH CHRISTIAN DAVIDSON. (L.B.)