Rotary grain screeners

A rotary grain screener is disclosed in which a reverse drive transmission assembly is provided at one end of the screener and in which a second drive transmission assembly is provided at the opposite end of the screener for driving an outer drum, an inner drum being secured to a central shaft which is driven from the outer drum through the reverse drive transmission assembly. The second drive transmission assembly also drives an auger in a pan which underlies the screens and a conveyor for conveying foreign materials upwardly out of the pan.

This invention relates to rotary grain screeners and more particularly to 
screeners which remove both coarse and fine foreign materials from grains. 
The screeners of the invention are easy to use and are very efficient 
while being rugged and highly reliable. They are compact and relatively 
simple, using a minimum number of component parts which may be readily 
assembled, the screeners being thereby economically manufacturable while 
also being easy to clean and service. 
BACKGROUND OF THE INVENTION 
Screeners for cleaning grain and the like have heretofore been provided 
which include one or more rotary screens to separate the grain from 
foreign materials. In one type of screener, inner and outer coaxial drums 
are provided, each including an annular screen supported by a plurality of 
axially spaced rims. The grain to be cleaned is supplied into the inner 
drum to fall through the screen thereof which may have a relatively coarse 
mesh, coarse foreign materials being retained within the inner drum. The 
outer drum has a fine mesh screen to allow fine foreign materials to pass 
therethrough, the grain being collected in the fine mesh screen of the 
outer drum for removal from one end thereof. 
In one type of construction, the coarse foreign materials are removed from 
one end of the inner drum by passing radially outwardly through a chute 
which is secured to the inside of the screen of the outer drum at a 
position intermediate the ends thereof. The coarse materials thus are 
discharged downwardly and may be received in a pan which also receives the 
fine foreign materials passing through the outer drum. The pan may be 
provided with an opening in its bottom and suitable auger means for moving 
the foreign materials to the opening. Drive means are provided for 
rotating the drums in opposite directions and in one type of construction, 
a pulley is connected through a shaft to the inner drum and is driven 
through a belt from a shaft which extends longitudinally alongside the 
drums, the shaft being driven by a motor and being also arranged to drive 
another belt to drive a pulley which is connected to the outer drum at the 
opposite end. 
SUMMARY OF THE INVENTION 
This invention was evolved with the general object of improving upon prior 
rotary grain screeners, increasing the efficiency thereof while also 
providing screeners which are easy to use and which at the same time are 
inexpensive to manufacture, rugged and reliable. 
An important aspect of the invention is in the recognition of the causes of 
problems with prior art constructions. More particularly, it is recognized 
that one of the problems has to do with the drive of the drums in opposite 
directions which has heretofore not only required a complicated 
construction with plural drive belts but has also been such as to make the 
screener difficult to manufacture and assemble. 
In a grain screener constructed in accordance with the invention, a reverse 
drive transmission assembly is provided which is preferably of a quite 
compact form and which includes first and second members journalled for 
rotation on the common axis of rotation of the two drums, such first and 
second members being rotated in opposite directions. The first member is 
coupled to the inner drum through spokes or the like which extend radially 
outwardly to a rim of the inner drum and the second member is similarly 
connected to a rim of the outer drum. 
Preferably, the inner drum is connected to a shaft which extends through a 
bushing to the first drive transmission member, the bushing being 
connected to the second drive transmission member and which is connected 
to the outer drum. A second drive transmission is provided for driving one 
of the drums from a motive power source such as an electric motor, the 
other drum being rotated in a reverse direction through the reverse drive 
transmission assembly. 
With this comparatively simple arrangement, the screener can be readily 
manufactured and assembled, using a minimum number of parts and at the 
same time, it is rugged and highly reliable in operation. 
In a preferred construction of the reverse drive transmission, one of the 
aforementioned first and second members thereof carries a gear which is 
meshed with a gear on a counter shaft, the counter shaft being coupled to 
the other member through a chain and two sprockets. Thus, a positive drive 
connection is obtained with a compact assembly which may preferably be 
enclosed in a protective housing and which may be lubricated as required 
to provide highly reliable service, with minimum maintenance. 
Another important advantage is that the drive occupies little space and as 
a result, the design, construction, operation and servicing of other 
components of the screener is facilitated. 
The reverse drive transmission is preferably provided at an end of the 
outer drum which is opposite the end of the drum at which a drum-drive 
transmission assembly is provided for drive from the motor or other power 
source. Preferably, the drum-drive transmission assembly drives the outer 
drum and most preferably, it includes a belt which is entrained about the 
outside of a rim portion of the outer drum. This arrangement is 
advantageous in that no separate pulley is required and in addition, the 
arrangement facilitates the construction and assembly of the components 
which are located adjacent to the one end of the outer drum. 
Another advantage of the drum-drive arrangement is that a shaft which 
carries a pulley for the drum-drive belt may be located on the underside 
of the drum on an axis which is relatively close to the axis of an auger 
in a collection pan below the drum, requiring only a relatively short 
drive belt connection to the auger. 
Another feature of the screener is in the provision of a built-in conveyor 
for transporting foreign materials from the collection pan to an elevated 
point from which they may be discharged, as desired. The materials need 
not be discharged from the underside of the pan and as a result, the pan 
can be located relatively close to the ground and the vertical height of 
the screener can be reduced. Preferably, the discharge conveyor is located 
at one end of the pan, close to the end at which the drum-drive is 
provided, and the vertical conveyor is driven through a belt from the 
auger shaft. 
The drum-drive arrangement of the invention is usable advantageously in 
screeners which have various arrangements for discharge of coarse foreign 
materials from the inner drum. In one type of screener, the inner screen 
is preferably of frusto-conical shape and it has a forward large diameter 
end for receiving grain to be cleaned. Coarse foreign materials are moved 
axially rearwardly and are moved from the small diameter end of the inner 
drum into a manifold positioned adjacent the rearward end of the outer 
drum. In one arrangement, the inner drum is shorter than the outer drum 
and the coarse foreign materials are moved axially from the small diameter 
end of the inner drum to the manifold through an axially extending conduit 
which may preferably be supported from a central shaft of the screens at a 
distance from the axis of rotation of the drums and which is rotated in a 
manner such as to receive materials from the inner drum and discharge them 
into the manifold. 
In another arrangement, the coarse materials are supplied to the manifold 
through an outlet screen which is effectively part of the inner drum and 
which may either be formed separately therefrom or as an integral 
extension thereof. The outlet screen in either case serves to clean as 
well as convey, retaining coarse materials while allowing grain to fall 
therethrough. When formed separately, a suitable bearing support for an 
intermediate rim of the outer drum may be provided between the end of the 
inner drum and the outlet screen. In the arrangement in which the outlet 
screen is formed as an integral extension of the inner drum screen, a 
bearing support for an intermediate rim of the outer drum may be provided 
from the outside, at the junction between the outlet and inner drum 
screens. 
Such arrangements have an important advantage in that the coarse foreign 
materials are conveyed axially to the manifold at an end of the screener 
opposite the end at which the grain to be cleaned is supplied to obtain 
improved cleaning action. No chute or other removing structure is secured 
to the inside of the outer screen. 
Another advantage of such arrangements is that the coarse foreign materials 
may be separately collected, if desired, or the coarse foreign materials 
may selectively be delivered back down into the lower collection pan to be 
mixed with the fine foreign materials. 
This invention contemplates other objects, features and advantages which 
will become more fully apparent from the following detailed description 
taken in conjunction with the accompanying drawings.

DESCRIPTION OF PREFERRED EMBODIMENTS 
Reference numeral 10 generally designates a screener constructed in 
accordance with the principles of the invention. The screener 10 is 
designed for cleaning grain such as shelled corn, soybeans, wheat, oats 
and the like and it includes a frame structure generally designated by 
reference numeral 11 which is supported on a pair of wheels 12, a tongue 
13 being provided for connection to a tractor or other vehicle to pull the 
screener to a desired operating location and a jack 14 being provided for 
support of the tongue 13. A feed-in conveyor 16 is supported during 
transport on one side of the machine in the manner as shown in FIG. 1. In 
use, the conveyor 16 may be swiveled around to a position in which grain 
may be dumped into a lower inlet end portion 17 and discharged from an 
upper outlet end 18 into an inlet chute 19 of the screener 10. 
The grain to be cleaned is fed through the inlet chute 19 into an inner 
drum 20 which includes an annular coarse mesh screen 22 supported between 
a pair of axially spaced annular rim portions 23 and 24. Coarse materials, 
such as pieces of stover, are retained by the screen 22. Grain and fine 
materials fall through the coarse mesh screen 22 into an outer drum 26 
which includes a rim 27 at the forward end of the screener and a rim 28 at 
the rear end thereof. The outer drum 26 further includes a fine mesh 
screen which is preferably in two sections 29 and 30, section 29 being 
disposed between the rim 27 and an intermediate rim 31 and section 30 
being disposed between the intermediate rim 31 and the rear rim 28. The 
fine mesh screen is of a mesh size such as to pass the fine foreign 
materials and to retain the whole grain. 
The grain collected in the outer drum 26 may preferably be removed 
therefrom at an outlet formed adjacent the lower end of the rim 28 at the 
rear end of the screener. The fine foreign materials which pass through 
the fine mesh screen sections 29 and 30 are collected in a pan 32 and are 
moved axially by an auger 33 to the front end of the pan, to be removed 
therefrom by a built-in auger 35 which conveys the materials upwardly 
through a conduit 36 to a discharge end 37 on one side of the screener 10. 
The inner drum 20 preferably has a frusto-conical shape as illustrated, 
such as to aid in insuring that the grain will pass through the coarse 
mesh screen 22 before reaching the rearward smaller diameter end thereof 
from which the coarse materials are removed. To remove the coarse 
materials, a generally cup-shaped housing part 38 is supported from a 
central shaft of the screener, on a hub 47 in surrounding relation to the 
smaller diameter outlet end of the inner drum 20 and it is connected 
through a conduit 39 to another cup-shaped housing part 40, also supported 
from the central shaft of the screener. In the illustrated construction, 
the housing part 38, conduit 39 and housing part 40 rotate with the outer 
drum 26. A stationary rear wall 41 is positioned in proximity to the 
rearward open end of the cup-shaped housing part 40 and is formed with a 
forwardly extending semi-cylindrical shroud portion 41A which underlies 
the part 40. Such components cooperate to define a manifold for collection 
of the coarse foreign materials which are sometimes referred to as 
"trash". The stationary rear wall 41 is formed with an opening 41B 
opposite the lower part of the outer drum to provide an exit opening for 
clean grain. 
In operation, the coarse foreign materials may move by gravity into the 
forward end of the conduit 39 when it is in its lowermost position, and 
subsequently will be discharged from the rearward end thereof into the 
manifold formed by the part 40 and the cooperating portions of the rear 
screener wall 41. With reference to FIGS. 2, 4 and 8, the coarse foreign 
materials collecting in the manifold formed by part 40 and the cooperating 
portion of the rear wall 41 may be discharged through an opening 42 in the 
rear wall 41 and through a stationary chute 43 and into another chute 44 
to be discharged into the rear end of the pan 32. The chutes 43 and 44 are 
disposed rearwardly of the outer drum 26. It is noted that the coarse 
materials may be selectively collected separate from the fine foreign 
materials, by removing the chute 44 and positioning a collecting container 
below the lower end of the chute 43, or by simply allowing the coarse 
foreign materials to collect on the ground. 
In the illustrated arrangement, the cup-shaped parts 38 and 40 and the 
conduit 39 are rotated with the outer drum, being connected to spokes 45 
and spokes 46 which extend radially from part 38 and bushing or hub 48 to 
the rims 31 and 28 of the outer drum 26. Alternatively, the components 38, 
39 and 40 may be connected to the inner drum for rotation therewith. 
Important features of the invention relate to the drive of the drums 20 and 
26 and the augers 33 and 35. In accordance with the invention, a reverse 
drive transmission assembly is provided in which a reverse drive is 
obtained between first and second drive members which are respectively 
connected to the two drums and which are journalled for rotation on the 
common axis of the two drums. The first drive member in the illustrated 
construction is a sprocket 49 which is drivingly connected through a chain 
50 to a second sprocket 51 secured to a shaft 52 on an axis parallel to 
the axis of rotation of the first sprocket 49. The second drive member in 
the illustrated construction is a gear 53 which is fixedly connected to 
the bushing 48 and thereby to the outer drum 26. Gear 53 is meshed with a 
gear 54 secured to the shaft 52 and sprocket 51 for rotation therewith. 
The sprocket 49 is fixedly secured to a central shaft 56 of the screener 
which is secured to the inner drum 20. The rearward end of the shaft 56 is 
journalled in a bearing 57 which is supported on a cross frame member 58. 
The frame member 58 also supports housing structure 59 of the drive 
transmission assembly, including wall portions 60 and 61 from which the 
shaft 52 is journalled. 
Gear 53 is fixedly connected to the bushing 48 which forms a hub for the 
outer drum 26 at the rear end of the screeners, bushing 48 being connected 
to the rear rim 28 of the outer drum through the spokes 46. The shaft 56 
is rotatable relative to the gear 53 and bushing 48 and extends 
therethrough to a forward end at which it is secured to the inner drum 20. 
The reverse drive transmission assembly operates to drive one drum in one 
direction when the other drum is driven from a motive power source in the 
reverse direction. In the illustrated screener, the outer drum 26 is 
driven through a drive transmission assembly at the forward end of the 
screener and drive torque is transmitted to the gear 53 through the spokes 
46 and bushing 48. Gear 53 drives the gear 54 in the reverse direction, 
the gear 54 being coupled through the sprocket 51, chain 50 and sprocket 
49 to the shaft 56 which is driven in the same direction as the gear 54 
and in a direction opposite the direction of the outer drum. Shaft 56 is 
coupled directly to the inner drum 20 to thus drive the inner drum in a 
direction opposite the direction of rotation of the outer drum 26. 
The reverse drive transmission assembly is of quite compact form and in the 
illustrated arrangement, it is positioned within the manifold formed by 
the part 40 and the cooperating portions of the rear wall 41, taking up 
very little space in the manifold. It is noted that the size of the gear, 
sprocket and chain components are disproportionately large in the 
illustration of FIG. 4 which is provided for explanation of the operation. 
Additional features of the drive arrangement relate to the drive of one of 
the drums, the outer drum 26 being preferably driven. With reference to 
FIGS. 3-6, the outer drum 26 is driven by a drive mechanism generally 
designated by reference numeral 64 and including a belt 65 which is 
entrained about the outside of the front rim 27 of the outer drum 26, it 
being noted that no separate pulley is thus required with the rim 27 being 
operative to perform two functions. The belt 65 is driven by a pulley 66 
which is secured to a shaft 67 supported and journalled by a bearing 68 on 
a cross frame member 69. Another pulley 70 is secured to the shaft 67 and 
is driven by a belt 71 from a pulley 72 on a shaft 73 of an electric motor 
74 mounted on the frame member 69. A take-up roller 75 engages the slack 
side of the belt 65 and is carried at one end of a lever 76 which is 
pivotally mounted on the frame member 69 with a tension spring 77 being 
connected to the opposite end of the lever 76 to urge the take-up roller 
75 into engagement with the belt 65. 
A central shaft portion 79 of the auger 33 has secured thereto at one end a 
pulley 80 which is coupled through a belt 81 to a pulley 82 which is 
secured to the inner end of the shaft 67, the auger 33 being thereby 
driven from the shaft 67 which is driven from the motor 74. 
To drive the vertical auger 35, a central shaft portion 83 thereof has 
secured thereto at its lower end a pulley 84 which is coupled through a 
belt 85 to a pulley 86 which is secured to one end of a shaft 87. An idler 
pulley 88 engages the belt 85 and is so positioned and journalled as to 
properly align the belt 85 with the pulleys 84 and 86 and to obtain the 
proper direction of rotation of the auger 35, it being noted that the axis 
of shafts 83 and 87 are at right angles to each other and do not 
intersect. At its outer end, shaft 87 carries a pulley 89 which is coupled 
through a belt 90 to a pulley 91 on the end of the shaft portion 79 of 
auger 33. 
With the arrangement as shown, the drive components are all relatively 
close together so that the belts can have short lengths and they are all 
located on the underside of the outer drum which is advantageous in that 
the entire front face of the drum assembly is clear of the drive 
components. It is noted that protective housing structure is disposed in 
front of the drive components, the screener being illustrated with such 
structure removed. 
As shown in FIGS. 3 and 8, the front end of the central support shaft 56 is 
journalled in a bearing 92 which is carried on the underside of a cross 
frame member 93. A bushing 94 is rotatably disposed on the shaft 56 
adjacent the bearing 92 and is connected through spokes 95 to the forward 
rim portion 27 of the outer drum 26. The outer drum 26 at its forward end 
may preferably have an end wall portion 96, a central opening 97 being 
provided in the wall 96 through which the grain to be cleaned is supplied. 
The forward and rearward rim portions 23 and 24 of the inner drum 20 are 
connected to the central shaft 56 through spokes 99 and 100, for rotation 
therewith. 
The rim 24 may extend within the cup-shaped part 38, as shown in FIG. 8. 
FIG.9 shows schematically the presently preferred screener utilizing this 
invention. In this screener, inner and outer drums 20' and 26' are 
supported from a central shaft 56', corresponding parts being indicated by 
primed numbers. In the screener of FIG. 9, a screen section 106 is 
provided which operates as a rearward extension of the inner drum but 
which is rotatable with the outer drum in the modification as shown. The 
screen section 106 includes a screen 107 which preferably has a coarse 
mesh like that of the drum 20', the screen 107 being carried between a 
pair of rims 109 and 110 which are respectively carried from the spokes 
45' and 46' of the outer drum 26'. The screen section 106 operates to 
perform a cleaning function in that grain which is received in the screen 
section 106 may pass through the screen 107 into the outer drum 26'. It 
also operates to convey coarse foreign materials to a manifold which is 
formed by the rim 110 and cooperating portions of the end wall 41' of the 
screener. 
As shown in FIG. 9, a baffle plate 111 is carried by a bushing 112 which is 
secured to the shaft 56' within the inner drum 20'. The baffle plate 111 
may be used to control the rate of flow of the coarse foreign materials 
and its position may be adjusted along the shaft 56'. A similar baffle 
plate is preferably provided in the first-described embodiment. 
FIG. 10 shows another screener which is similar to the screener of FIG. 9 
and which includes an outer drum 26" similar to the drums 26 and 26', 
corresponding parts being indicated by double-primed numerals. 
In the screener of FIG. 10, a screen section 114 is provided which is 
similar to the screen section 106 of FIG. 9 but is rotatable with the 
inner drum 20". The arrangement includes a rim 115 which forms both the 
rearward rim of the frusto-conical section of the inner drum 20' and the 
forward rim of the screen section 114, the rim 115 being secured to a 
central shaft 56" through spokes 116. At its rearward end, the screen 
section 114 includes a rim 117 which is supported from the shaft 56" 
through spokes 118. 
As also illustrated in FIG. 10, the outer drum 26" may include an 
intermediate rim 120 supported through spokes 121 from a hub in the form 
of a ring 122 which is journalled on the outside of the rim 115 through a 
suitable bearing 123. It will be appreciated that if desired, the outer 
drum may be so constructed as not to require bearing support of an 
intermediate rim thereof. 
The arrangement of FIG. 10 operates in the same manner as the arrangement 
of FIG. 9, except that the screen section 114 rotates with the 
frusto-conical inner drum screen section, rather than in an opposite 
direction as is the case with respect to the screen section 106 in the 
FIG. 9. 
It will be understood that modifications and variations may be effected 
without departing from the spirit and scope of the novel concepts of this 
invention.