IMPROVEMENTS IN THRESHING MACHINES
Year: 1879

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
THRESHING MACHINES." A communication from abroad by the Firm of
R. & T. Elworthy, of Elizabethgrad, in the Empire of Russia.
Sealed the 27th February 1880, and dated the 15th December 1879.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 15th December 1879.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN THRESHING MACHINES." A communication from
abroad by the Firm of R. & T. Elworthy, of Elizabethgrad, in the Empire of
Russia.
This Invention relating to improvements in threshing machines has for its object
providing a threshing drum and concave which shall combine all the advantages of
what are known as the "beater "and "toothed" systems without their accompanying
disadvantages.
In carrying out this Invention in order to effect this object, it is proposed to
employ bars, say, for example, of flat iron or wood armed with triangularly shaped
teeth, and fastened to wheels or centres in order to constitute the drum which is
keyed on to a spindle mounted so as to be capable of revolving in suitable bearings.
The shape of the teeth is an isosceles triangle whose two sides stand to each other at
an angle of, say, about 45 degrees. The concave is composed of segments or
sections bolted together, and to quadrants or sectors at the ends; it is held in place
by rods passing through the end quadrants or sectors and eye bolts; these eye bolts
with their nuts also serve to adjust the concave in height. The concave sections
have teeth similarly formed to the drum teeth and so arranged that the drum teeth
may pass regularly between them. Ribs are provided which extend circumferen-
tially from the centre of each tooth to the next in succession. These ribs stand up
as high towards the points of the teeth as is possible without diminishing the
efficiency of the teeth for impact in threshing, and their object is to guide the
straw, preventing its being driven across the teeth, and being broken as in the

page_text: ordinary toothed system. The spaces between the ribs are an open grating through
which the threshed grain falls.
The teeth of the concave may be made in one piece with a whole section of the
same comprising one, two, or more rows in each section, or the teeth of the drum
and concave may be made in bars of malleable cast iron, a whole row of teeth in
each bar, these bars being again bolted to wooden bars in the same manner as in
the ordinary English beater.
--
By means of this Invention the following advantages are obtained :-
1. The greatest possible aggregate length of "line of threshing action," so that
the grain being threshed is spread in the thinnest layers, and is subject to the most
effective impact without the crushing action peculiar to the beater system, thereby
ensuring rapid and clean threshing without waste of power.
2. The clearance between the teeth of the drum when in rotation and the
concave teeth can be varied at will to suit different qualities of grain by raising or
lowering the concave. This cannot be effectively done according to the common
toothed system.
3. Through the guiding action of the ribs the grain is threshed out without
hacking and breaking the straw as in the ordinary toothed system.
4. The teeth of both drum and concave being formed with the same inclination
on both their front and back faces are reversible, so that when one side is worn
away a new side can be brought into action by removing and refixing the teeth in
the reverse direction or in the concave by reversing a whole section.
In the ordinary toothed system this is not possible, seeing that the sides of the
teeth being nearly parallel they are necessarily curved or otherwise much inclined
backwards to enable them to throw the straw off freely.
The Invention is chiefly applicable in those cases in which the sheaves of grain
are fed endways on into the drum.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
tho said John Henry Johnson in the Great Seal Patent Office on the 20th
May 1880.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN THRESHING MACHINES." A. communication from
abroad by the Firm of R. and T. Elworthy, of Elizabethgrad, in the Empire of
Russia.
The said Invention has for its object providing a threshing drum and concave
which shall combine all the advantages of the two clases of machines known
as the "beater system" and the " toothed" system, without their accompanying dis-
advantages. It is expedient therefore first to consider the construction and working
of these two systems in order that the improvements proposed may be more clearly
understood. In the "beater" system the threshing is performed by a "drum" having
on its periphery from 4 to 8 straight bars of iron or steel called beaters. Beneath

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the drum and in close contiguity to it is fixed a concave also armed with straight
bars. The drum is brought into rapid rotation, and the unthreshed grain being fed
in at the back is threshed out in its passage between drum and concave. In some
cases the beaters, in others the concave bars already mentioned, are sometimes
serrated diagonally on the flat side of the bar, but their effect is the same in this
respect, videlicet, that the figure described by the drum in rotation is a plain
cylinder, and the line of threshing action or narrow space between the revolving
drum and the concave, as would be shewn by a section taken parallel to the
drum's axis, is a straight and parallel opening whose length equals the breadth of
the machine. The "beater" system has this advantage that the clearance between the
threshing surfaces of drum and concave can be varied at will to suit the different
kinds of grain by raising or lowering the concave. Its disadvantage however, except
in cases where the sheaths are fed transversely into the machine, is that the line
of threshing action being straight is of much less extent than in machines of the
toothed system. In the latter both drum and concave are armed with teeth so
arranged that the teeth of the drum in their rotation pass regularly between those
of the concave and the opening then described between them, when shown in section
parallel to the drum's axis is of zig zag form. This opening constitutes the "line" of
threshing action, which being in this case of zig zag form is therefore of greater
extent than the straight line of the beater system before mentioned.
The toothed system has however this disadvantage that the distance between the
threshing surfaces of drum teeth and of concave teeth cannot be varied, for although
the concave may be raised or lowered, yet the teeth being narrow and very slightly
tapered, the clearance laterally between the teeth of the drum and those of the
concave remains practically the same. With this system is also no provision made
to prevent the straw from being driven indiscriminately amongst the teeth, and
thus becoming broken across them, hence the straw threshed in these machines is
always more or less hacked and broken.
Now according to the present Invention the advantages of both systems are
retained without their accompanying disadvantages by constructing the machine
in the manner hereinafter described, reference being had to the Sheet of Drawings
hereunto annexed.
In the accompanying Drawing of the improved drum and coucave Figure 1 is a
section taken longitudinally of the machine, that is to say, transversely of the axis
of drum and concave; Figure 2 is a vertical section taken transversely or axially
of the same; Figure 3 shows the inside of the concave looking downwards on it;
Figures 4 and 5 illustrate another method of applying the Invention which will be
hereinafter described.
Referring to Figures 1, 2, and 3 of the accompanying Drawing, the flat iron bars
a armed with the triangularly shaped teeth B and fastened to the wheels or centres c
constitute the drum, which being keyed on its spindle & revolves in bearings e.
The shape of the teeth is an isoceles triangle whose two sides stand to each other
at an angle of about forty five degrees. If preferred these teeth may be fastened
into wooden bars instead of iron, as shewn.
The concave is composed of the segments or sections / bolted together, and to the
quadrant g at the end with bolts, and held in place by the rods passing through
the quadrants g and the eye bolts m. These eye bolts with their nuts also serve
to adjust the concave in height. The concave is provided with teeth i of similar
form to the drum teeth, and so arranged that the drum teeth b in their revolution
may pass regularly between them. In each parallel row of teeth in the concave
extending from tooth to tooth concentrically with the drum's axis are provided
ribs which stand up as high towards the points of the teeth as is possible without
diminishing the efficiency of the teeth for impact in threshing. The object of these
ribs k is to guide the straw in its passage through keeping it straight and preventing
it from being driven across the teeth i and being broken, as in the ordinary toothed
system before described. The spaces between the ribs k are an open grating
through which the threshed grain falls.

page_text: If preferred the concave may be made without the open grating, and may be
placed inversely above the drum instead of below.
Figures 4 and 5 shew sections of a drum and concave fitted with teeth of the same
shape as the foregoing, but made in bars of malleable cast iron, a whole row of teeth
in each bar, these bars being bolted to wooden bars in the same manner as the
ordinary English beaters.
In this machine the sheaths of grain are fed in endwise in the same manner as
in machines of the ordinary toothed system. By means of the said Invention the
following advantages are obtained, videlicet:-
(1.) The clearance between the threshing surfaces of the teeth of the drum when
in rotation, and the concave teeth can be varied at will to suit different kinds of
grain by raising or lowering the concave. This, as before explained, cannot be
effectually done in machines of the ordinary toothed system.
(2.) Through the guiding action of the ribs & the grain is threshed out without
hacking and tearing the straw as in the ordinary toothed system.
(3.) The greatest possible aggregate length of line of threshing action ensuring
rapid and clean threshing without the waste of power due, in the beater machines,
to undue pressure on the straw between the threshing surfaces, and in the common
toothed machines to their hacking and tearing action on the straw.
(4.) The teeth of both drum and concave being formed with the same inclination
on both their front and back faces are reversible, so that when one side is worn
away a new side can be brought into action by reversing either the entire drum
or its teeth singly, and in the concave any or all of its sections may be reversed.
In the ordinary, toothed system of machines this is not possible, seeing that the sides
of the teeth being nearly parallel they are necessarily curved or otherwise much
inclined backwards to enable them to throw the straw off freely.
Having now described and particularly ascertained the nature of the said Inven-
tion, and the manner in which the same is or may be used or carried into effect, I
would observe in conclusion that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the hereinbefore in part recited
Letters Patent is,―
The general construction, arrangement, and combination of parts constituting a
threshing machine, substantially as hereinbefore described and illustrated by the
accompanying Drawings.
In witness whereof, I, the said John Henry Johnson, have to this my Specifi
cation set my hand and seal, the Twentieth day of May, One thousand
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