Improvements in Shaking Screens for Sifting Grain and other Granular Substances:
Year: 1886

page_text: Date of Application, 22nd Apr., 1886.
Complete Left, 18th Jan., 1887.
Complete Accepted, 22nd Feb., 1887.
Improvements in Shaking Screens for Sifting Grain and other
Granular Substances:
I, GUSTAV EISNER, of Kojetein, Moravia, Austria, Manufacturer, do hereby declare
the nature of this invention to be as follows-
This invention relates to shaking screens such as are used. for winnowing and
sifting grain and other granular substances. My invention has for its object to
provide means for varying at pleasure the intervals between the longitudinal wires or
thin rods of which the working surface of the, screen is composed. The invention
consists in arranging beneath tho said wires or thin rods, and crosswise of the same,
a certain number of shafts which have their bearings connected to the frame of the
screen and carry discs that are movable end wise and project into the said intervals
and have one face formed by a right hand helicoidal surface and the other face by a
left hand holicoidal surface. In consequence of the described form of the faces of tho
dises, each disc may be looked on as a wedge, so wound or curved round the shaft as to
have its edge placed radially. In order to enable the wires or thin rods forming the
screen, to alter their positions, according to the thickness of the portion of the circum-
ference of the discs which is placed between them, their ends are loosely inserted into
grooves of the front and back bars of the frame of the screen, and to keep the wires
and discs always closely together, two bars, having their ends likewise engaged in the
said grooves, border the whole series of wires or thin rods and are forced toward each
other by means of springs or binding screws.
The shafts carrying the endwise movable discs may each have an individual crank
with a suitable contrivance for fixing it in the desired position, in which case a con-
verging position may be given at will to the wires or thin rods, and thus the offals
may be separated into several sets comprising particles of different sizes; or all shafts
may have a common driving mechanism.
Another series of shafts or bars not connected to the swinging frame and carrying
loose thin discs may be interposed between the described shafts; the said thin dises
being destined to free the intervals between the wires from chaff, dust and the like,
while the screen is swinging.
To prevent the grain from being wedged in between the wires and regulating discs
the said dises are preferably covered by a trough-shaped piece of sheet iron.

page_text: I, GUSTAV EISNER, of Kojetein, Moravia, Austria, Manufacturer, do hereby declare
the nature of this invention and in what manner the same is to be performed, to bo
particularly described and ascertained in and by the following statement:
This invention relates to shaking screens such as are used for winnowing and sifting
grain and other granular substances.
My invention has for its object to provide means for varying at pleasure the
intervals between the longitudinal wires or thin rods of which the working surface of
the screen is composed.
For this purpose the onds of the wires or thin rods forming the screen being loosely
inserted into grooves in the front and back girders of the frame, there are arranged
transversely beneath these wires or thin rods a certain number of shafts, which carry
discs that are movable endwise and project into the intervals between the wires, each
disc having its circumference gradually increasing in thickness from one point
onwards, so as to form a circular wedge. All the wires and discs are pressed towards
each other by springs.
Between each pair of the shafts I prefer to place rods, which are parallel to the
shafts, but, not being connected to the swinging frame of the screen, do not move with
it, these rods carrying loose discs of thin sheet metal, which project into the intervals
between the wires in order to loosen material that may be wedged in between them.
Or long narrow brushes made of strong fibres may be employed for this purpose.
Figure 1 of the accompanying drawings is a side elevation of a shaking screen
according to this invention.
Figure 2 is a plan.
Figure 3 shows to an enlarged scale part of a cross section taken in front of one of
the shafts that carry the adjusting discs, and part of a cross section in front of 'one of
the rods that carry clearing discs.
Figure 4 is a sectional side view of part of the screen, showing a pair of adjusting
dises and a clearing disc.
Figure 5 and 6 are respectively a part cross section and part longitudinal section
shewing brushes applied instead of clearing discs.
Figure 7 shows on a reduced scale a side elevation of a shaking screen, having its
clearing brushes supported by a separate frame which may swing in directions opposite
to those of the screen.
Figure 8 is a cross section on line X X, Figure 7.
Figures 9 and 10 are a front and edge view respectively of one of the
adjusting discs.
The frame a of the screen is as usual suspended in an inclined position on
springs. b. b. and. is caused to oscillate by the crank c linked to it by the forked
connecting-rod d.
The ends of the wires or thin rods e, which form the screen are inserted loose into
grooves of the front and back ends a', a² of the frame. Below the wires e, shafts fare

page_text: g
mounted in the side bars of the frame a and on these shafts are fitted discs g-free
to slide along the shafts but turning with them. These discs project up into the
intervals between the wires e. As shown by Figures 9 and 10 each of the discs has
helicoidal surfaces the one side right and the other left handed so that it may be considered
a wedge, so wound round its shaft.
As a simple way of causing the discs g to turn
with their shafts f, each shaft has a portion of its circumference flattened and the
central holes of the discs g are shaped to correspond as shewn in Figures 4, 6 and 9.
Coiled springs placed on both ends of each shaft f, bear against longitudinal bars i
which are of shaped cross-section, and can move sideways along the shafts and
along cross guides, which connect the two sides of the screen frame a. By turning
the shafts thicker or thinner portions of the circumferences of the discs g can bo
brought between the wires e and thus the intervals between these wires may be
widened or narrowed at pleasure. Small coiled springs & interposed between each
pair of the discs y transmit the pressure through the row of discs and prevent them
from taking oblique positions on their shafts, such as might cause them to clutch the
shafts and interfere with their adjustment.
As shewn in Figure 4, the cross guides are curved in cross-section and being
placed immediately above the discs g, prevent particles of the material which is sifted
from accumulating between the discs g and the springs k.
Each of the shafts may be turned separately by a wrench applied to their squared
ends (Figure 3) and fixed in the desired position by setting screws m (Figure 3). In
this way the sieve may have different widths of interstices at different parts of its
length. It is preferred however to connect the shafts to mechanism for turning them
all simultaneously,
Thus all the shafts for a number of them may carry worm-wheels n, gearing with
worms on a shaft o which is mounted in bearings on the sides of the frame a and can
be turned by cranks o².
Beneath the frame a there is a second frame which may either be rigidly
supported as shown in Figure 1; or may be suspended by springs bb, as shown in
Figures 7 and 8. In the latter case, the driving shaft e has two cranks, c' which is
linked by d to the sieve a, and opposite to another crank c² which is linked by q to
the frame and causes it to oscillate always in a direction opposite to a.
The frame p carried by brackets rods which are placed between each pair of the
shafts and carry thin sheet metal disks that are loose on the rods and project up
between the wires e, so that, while the screen is swinging, the discs t relatively moving
to and fro between the wires loosen any material jammed between them.
Instead of the discs narrow brushes may be supported by the brackets of the
frame p, as shown in Figures 5, 6, 7 and 8. These brushes are by preference made of
strong fibres such as piassava-fibres, compressed between two bars.
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. In combination with the thin rods or wires constituting a screen, shafts / carrying
springs and wedge discs projecting into the intervals between the wires substantially
as and for the purpose set forth.
2. The combination with the wires e, the shafts, the wedge discs g, the springs h
and k, and the curved cross guides, covering the discs g, substantially as and for the
purpose set forth.
3. In combination with the screen a, an under frame p, carrying thin discs t,
projecting into the intervals between the wires e substantially as and for the purpose
described.
ABEL & IMRAY.