Improvements in Grain Separating Screens for Thrashing Machines.
Year: 1895

page_text: ate of Application, 15th Oct., 1895-Accented. 23rd Nov., 1945
COMPLETE SPECIFICATION.
Improvements in Grain Separating Screens for Thrashing Machines.
I, CHARLES CLOSz, of Webster City, in the County of Hamilton, and State
of Iowa, United States of America, Gentleman, do hereby declare the nature of
this invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
The screen produced by my present improvement is for separating the grain aul
the chaff from the straw as it is carried out from the cylin ler of a thrashing
machine to the straw stack by the vibratory movement of the earrier which is
operated from the thrashing cylinder.
The construction of the separating surface which constitutes my present
improvement is illustrated in the acompanying drawings which, in connection
with the following description, and the concluding claims will preis ly set out the
parts which distinguish between what is old and what is claimed as new.
Referring to these drawings:-
Figure 1 shows in top view so much of a corrugated metal screen of transverse
openings as illustrates the improved construction.
Figure 2 is a vertical longitudinal section of the same taken centrally crossing
the openings on the line - of Fig. 1.
Figure 3 is a similar sertion taken on the line of Fig. 1.
Figure 4 is a cross section on the line
of Fig. 1 looking war! the delivery
end of the sereen the line of section being taken through the transverse opening
between the corrugations.
Figure 5 shows in perspective the formation of the surface of one of the strips
between the openings.
Figure 6 shows a portion of one of the corrugations of the screen in perspective
illustrating a novel construction of notching the corrugations.
Figure 7 is a similar view to Fig. 4 looking toward the receiving end of the
screen and showing the corrugations notched and lipped as in Fig. 6.
It will be understood that the screen is of sheet metal, the corrugations and
openings whereof are struck up as to form a stiff platform and that it is mounte
to receive the straw and grain from the thrashing cylinder and carry off the straw
and separate the grain and chaff from it through the screen openings by an endwise
vibratory movement of the screen and an air-blast provided beneath the screen to
separate the chaff and fine straw from the grain.
The serening surface is produced by transverse openings formed between
longitudinal corrugations 1, the distance between which may be from one-and-a-half
to two and a half inches and the number of the corrugations will be governel by
the width of the platform.
The corrugations extend from the receiving to the delivery end of the platform
and may be constructed as I shall presently state. The openings between the
carrugations are formed by cuts approximating the form of a bow and the surface
between them is so formed and shaped as to present edges raised above the base
lines of the corrugations and depressed below them so that the between surface
will stand inclining downward toward the receiving end of the screen. The
openings thus formed between the top edge of one surface and the bottom edge of
the next contiguous surface have their greatest width along a longitudinat line
mediately between the corrugations. At this part 2 of greatest width of the
openings the top edge 3 is turned bark concave and the surface between the-e

page_text: edges 3 and 4 is steep about 45 from a vertical line and convex and concave and
Jess steep on each side of the middl as at 9, Fig. 3.
The ends of the cuts join the base of the corrugations and the surface 6-6 at
such ends is flat along the corrugations, while the top edge from such flat surface
joins the turned-back concave part 3 by a forward standing convex part 7 about
midway between the ends 5, 5, and the middle line of the concave 3. This gives
the lower elge 8 of the surface a concave form corresponding to the top convex
part 7.
Between the top flat surfaces 6, 6, and the lower concave edges 8, 8, there is a
depression 9 curving from the corrugation into the conenve edge 8. From its
widest part 2 the opening decreases in width and the steepest part of the surface
is at its turned-back part 3. This steep surface is at the widest part of the opening
and affords a free and unobstructed discharge for the grain. The concave or
turned-back center of top edge and its steep convex surface is for the purpose of
directing the straw toward and over the forward sloping elges which terminate in
the forward standing convex part- 7, 7, and it is important to notice that this ton
edge between the convex parts 7, 7, is horizontal and forms a level ridge and cross
support for the straw as seen in Figs. 4 and 7. The flat surfaces 6, 6, along the
corrugations serve to facilitate the forward movement of the straw as it slides over
the edges which curve from the convex parts 7, 7, to and upon the flat surfaces,
The depression 9, 9, serve to check and to prevent the movement of the grain
with the straw over the edge between the convex parts 7,7, and the that f6,6.
and to direct it downward through the opening. For this purpose I form a ridge 14
standing out from the flat surface ó above the cavity and about parallel with the
eage of the strip to the parts 7.
-fraw.
When so
The corrugations serve to stillen the platform and stand above the top edges of
the separating surface to carry the straw above it and so hold it in a more loose
condition and thereby facilitate the separation of the grain and the chaff from the
For this purpose the top ilges of the corrugations may be unbroken as
shown in Fig. 2 or they may be notched as shown in Fig. 6 and 7.
notched I make the corrugati as higher above the separating surface and with their
walls joined so that the notches 10 can be made saw-tooth shaped in the top elges
as if in a single plate with the shoulder 11 of the notches Standing toward the
delivery end of the screen. These notches while serving to give a more effective
movement to the straw and to hold it better above the surface, are utilized to give
strength to the corrugations both sidewise and vertically by turning the cut parts
as laps 12 over upon and against the sides of the corrugations. The lapping of the
ent parts may be made on alternate sides to equalize the bracing or on one side
only of the corrugations and it is done by ben hing the cut parts and turning them
down as laps flat against the walls by pressure so that they form laps of four
thicknesses very greatly increasing the strength of the corrugations and of the sheet
which forms the platform.
It is important to notice that the flat surfaces 6, 6, at the ends of the cuts are
considerably in advance (looking toward the delivery end of the screen) of the
turned-back concave center point so that the edge from the concave 3 to the
convex parts 7 stands obliquely forward from each side of the concave which gives
a parting sidewise feed to the straw to open it as it moves forward and sidewise to
the flat surfaces.
It is also important to notice that the convex at the turned-back center part is
much steeper than the concave part which joins the that surfaces so that these steep
convex parts serve to stiffen the platform mediately between the corrugations, as
seen in Figs. 2 and 3.
The strengthening and bracing of the screen by the reinforcing of its corrugationS
by notching and lapping the metal from said notches upon the sides of the
corrugations may be used with any suitable construction of separating surface.
The steep pitch of the surface seen in Figs. 2 and 3 is at the middle of the
length of the opening and at this point the latter is widest, and this so far as I know,

page_text: is a new construction. The level top edge of the strip is between the parts 7, 7,
Figs. 2 and 3 and from these parts 7, 7, the edge curves downward to the
corrugations. This construction is also new to me, and I obtain this construction
by the deep-set-back 3 at the top edge of the strip, so that at this set-back point
the top edge will be considerably back of the dotted line 16 drawn from the ends
of the opening and will intersect a cross line 15 at about mediately the width of
said strip, as seen in Fig. 1. This is a feature wherein my improvement resides
for effecting a free and unobstructed delivery of the grain and chaff from the straw,
and the freest movement of the straw over the edges of the strips.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
1. A sheet metal screen for separating grain having corrugations and between
them transverse openings, the strips providing said openings, each having its upper
edge set-back of the transverse lice 16 at a point mediately of the length of said
strip, so that the greatest depth of such set-back will intersect a line drawn about
mediately the width of said strip, the surface at said set-back being convex and of
greater pitch than the surface at the ends of the strip, whereby the openings have
their greatest width mediately of their length, for the purpose stated.
2. A sheet metal grain separating screen having corrugations and between them
transverse openings the strip providing said openings having steep convex pitch
mediately of their length and which merges into less pitch toward each end, the
surface depressions 9, 9 and the ridges 14, 14, extending from the flat surfaces 6, 6,
about parallel with the top edge to the parts 7, the said top edge being set back of
a line connecting the ends of the opening, to about half the width of the strip,
aubstantially as described.
3. A sheet metal air separating screen having parallel corrugations and
between them openings the said corrugations ...ing their upper edges notched and
the metal displaced by said notching turned down as laps against the vertical wall
of said corrugations and forming thereby saw-tooth shaped notches, for the purpose
stated.
4. A sheet metal grain separating screen having openings separated by parallel
corrugations which have their upper edges of saw-tooth form, the metal displaced
to form such teeth being turned down alternately on opposite sides of the said
corrugations to equalize the bracing and strengthening effect of such laps upon the
corrugations and the screen.
Dated this 15th day of October 1895.
BOULT & WADE,
Agents for the Applicant.