A trommel cleaner apparatus having a non-circular rotatable shaft with a plurality of flapper elements mounted thereto for wiping and cleaning engagement with a trommel is provided herein. The flapper elements each have a hub having inner and outer surfaces, with the outer surface including a plurality of flappers extending therefrom so as to engage a trommel in cleaning operation and with the inner surface including a plurality of indexing lobes to variably position the flapper element relative to the shaft and adjacent flapper elements, thereby reducing the torque spikes applied to the trommel.

FIELD OF THE INVENTION 
The present invention relates rotating trommels used to sort or size 
particulate matter in general and to an improved cleaner apparatus and 
drive system therefor used to clean the screens used in the trommel. 
BACKGROUND OF THE PRESENT INVENTION 
Rotating apparatus known as trommels have long been used to screen dirt, 
debris, and other undesirable material from desirable material as well as 
to sort or size particulate material, such as grains. In general, the 
trommels have a cylindrical configuration defined by a skeletal framework 
and one or more screen panels attached thereto. The screen panels each 
have a plurality of sorting (or sizing) holes or apertures therein that 
serve to pass particulate matter therethrough below a certain size range. 
The particulate matter is inserted into the trommel in one end thereof 
and, as the trommel rotates the undersized particles are passed through 
the holes into the appropriate collection apparatus disposed therebelow. 
In this manner, grain such as seed corn, oats, barley, etc. can be sorted 
according to size. Many times the materials are subjected to multiple 
sortings, sometimes within the same overall apparatus. In addition, there 
are several companies that place multiple trommels within a single unit, 
which will be referred to as a sizer hereafter. 
As the material within the trommel rotates, particles slightly too large to 
pass through the apertures can become lodged therein. Within a very short 
time of beginning the sorting or sizing operation, the screen apertures 
can nearly all become completely obstructed, thereby preventing anymore 
material from passing therethrough and essentially ending the sorting 
operation as it begins. To prevent this from occurring, it is known in the 
art to use a variety of devices to clean the screen apertures as the 
screen is rotated. One such device uses a plurality of cylindrical rollers 
mounted on a shaft for free rotation relative thereto. The shaft is 
disposed above the trommel in such a manner that the rollers can rollingly 
engage the trommel. Friction between the trommel and the rollers causes 
the rollers to rotate as the trommel is rotated. The rollers are typically 
made of wooden or other suitable material. As the trommel rotates then, 
the rollers engage the portions of the particulate material extending 
through the sorting aperture and force the material out of the apertures 
and back into the interior of the trommel, thus opening the apertures so 
they can be used to sort material as intended. Another known type of 
screen cleaner utilizes an elongate cylindrical brush that cleans the 
screens by means of the brush bristles extending into the sorting 
apertures as the trommel rotates, forcing the material out of the 
apertures. 
Still another form of trommel cleaner utilizes an elongate cleaner that 
includes a plurality, typically few in number, of flappers that extend 
outward from a central hub and into contact with the trommel. The flappers 
extend the length of the trommel and have a rectangular cross section. 
These units work well in cleaning the trommel screen, but are accompanied 
by several deficiencies. As the elongate flapper engages the trommel along 
its entire length, that is, as it slaps against the trommel, knocking the 
stuck material from the sizing holes, a torque spike is created that must 
be accommodated by the drive unit. Thus, a plurality of torque spikes 
equal to the number of flappers is created with each revolution of the 
trommel cleaner. These torque spikes necessitated the use of heavier 
elements than would otherwise be necessary in the drive system. In 
addition, the torque spikes most likely shortened the lifetime of all of 
the elements of the trommel system. Finally, this type of trommel cleaner 
requires a separate drive system to drive the cleaning unit. That is, they 
cannot be friction driven like the rollers and must have their own drive 
system comprising chains (or belts) and gears (or pulleys). 
It would be desirable to have a trommel cleaner that provided the cleaning 
advantages of the flapper cleaners but that did not create the torque 
spikes found in such prior art cleaners. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide new and improved 
apparatus that is not subject to the foregoing disadvantages. 
It is another object of the present invention to provide an improved 
trommel cleaner that provides the cleaning advantages of the flapper-type 
cleaner but that does not create the torque spikes that those types of 
cleaners do. 
It is still another object of the present invention to provide an improved 
trommel cleaner that includes a plurality of flapper elements that 
together extend substantially the length of the trommel. 
It is yet another object of the present invention to provide an improved 
trommel cleaner of the flapper type that can be driven by a friction drive 
rather than a separate chain or belt drive. 
It is still yet another object of the present invention to provide an 
improved trommel cleaning apparatus comprising a plurality of individual, 
substantially identical, flapper elements mounted to a shaft for rotation 
thereabout. 
The foregoing objects of the present invention are provided by a trommel 
cleaner apparatus in accord with the present invention, the trommel 
cleaner having a shaft having a non-circular outer surface. The shaft 
mounts a plurality of flapper elements thereon. Each flapper element has a 
hub having an inner and outer surface. A plurality of indexing lobes 
extend inwardly from the inner surface of the hub. The indexing lobes and 
the non-circular shaft cooperate to enable adjacent flapper elements to be 
mounted to the shaft with flappers of one flapper element angularly 
disposed relative to the flappers of the adjacent flapper elements. In the 
embodiment shown in the Figures, the flapper element has five flappers 
disposed symmetrically about the hub such that the flappers extend 
outwardly from their bases which are in turn disposed about 72.degree. 
apart. With eight indexing lobes as shown and a square shaft as shown, the 
flappers can be disposed about 9.degree. apart. Thus, the torque spike is 
reduced because flappers will be striking along one eighth of the trommel 
compared to the entire length as with the prior art flapper cleaner. The 
torque spike is thus reduced to one eighth of that found in the prior art, 
thereby enabling the drive system for the trommel to be made of "lighter" 
components, enabling the trommel cleaner to be driven by a friction wheel 
engaged with the trommel, and lengthening the life span of all of the 
component parts due to the reduced torque that the trommel, the trommel 
drive and the trommel cleaner apparatus must bear.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIG. 1, a sizer 10 in accord with the present invention is 
illustrated. Sizer 10 is used to sort undesirable from desirable 
particulate matter as well as to sort the particulate matter by size, such 
as the girth of a kernel of grain. As best seen in FIGS. 1-3, the sizer 10 
illustrated includes four trommels arranged with two trommels side by side 
and directly over the other two. Sizers including one or more trommels are 
well known and the present invention is not limited to the present 
configuration shown herein. 
As shown in the Figures, sizer 10 includes first and second, or lower and 
upper, modules 12 and 14. Modules 12 and 14 are attached to each other by 
fasteners 16, which may be nut/bolt combinations. Module 12 is in turn 
fastened to a base 18 by fasteners 20, which may also be nut/bolt 
combinations. Module 12 includes a pair of trommels 22 and 24 mounted 
side-by-side for rotation therein. Similarly, module 14 includes trommels 
26 and 28 mounted in a side-by-side manner for rotation therein. Modules 
12 and 14 have a substantially elongate, box-like configuration with the 
axis of rotation of the trommels defining the longitudinal direction. 
Transverse to the axis of rotation, the modules 12 and 14 each have a 
substantially rectangular configuration. Modules 12 and 14 each have an 
outer, four sided shell 30 and 32 respectively that mounts the trommels 
22, 24 and 26, 28 therein, respectively. Shells 30 and 32 are typically 
manufactured from steel, though wood or other materials of suitable 
strength may appropriately be used. 
Referring to FIGS. 1 and 2 particularly, now, it will be observed that 
sizer 10 includes a hopper 34 into which the particulate material 36 to be 
sorted is placed. Hopper 34 includes a plurality of branches therefrom 
that lead to the trommels within sizer 10. Thus, hopper 34 includes a 
branch 38 leading to trommel 22; a branch 40 leading to trommel 24; a 
branch 42 leading to trommel 26; and a branch 44 leading to trommel 28. It 
will be observed in FIG. 2 that hopper branches 38 and 40 are sub-branches 
of a larger main branch 46. The particulate matter 36 drops into hopper 34 
and falls under the influence of gravity into branches 42, 44, and 46, and 
from branch 46 into branches 38 and 40. From the branches 38-44 the 
particulate matter flows into the trommels 22-28, respectively, in a known 
manner at the inlet ends thereof. Branches 38-46 may be formed of sheet 
steel or other appropriate materials. 
Material passing through the trommel screens of trommels 22 and 24 is 
received by a receiving hopper 48. Hopper 48 has an elongate configuration 
with sloping side walls 50, 52 that converge near the bottom into an 
outlet channel 54, which in turn may empty into a conveyor (not shown). 
Similarly, material passing through the trommel screens of trommels 26 and 
28 is received by an upper receiving hopper 56 that has sloping, 
converging side walls 58, 60 that empty into a channel 62. Channel 62 in 
turn empties the sorted material into lower receiving hopper 48. Material 
that does not pass through the screen openings in trommels 22-28 is 
carried through the trommels to the discharge ends thereof and discharged 
into a collection hopper 64, from which it flows into another conveyor 
(not shown). It will be understood that dependent upon the particulate 
matter 36 being screened or sized, that the material flowing into hopper 
48 may be discarded or kept and that the same is true of the material 
flowing into hopper 64. 
Referring now to FIGS. 1, 3, and 4, the drive mechanism for the trommels 
will be explained. Upper module 14 includes a support plate 66 attached 
thereto in any known manner that extends outwardly therefrom. Support 
plate 66 has a substantially triangular configuration as shown, though 
this is not critical to the present invention. A drive motor 68 is 
suspended therefrom though it could also be supported thereabove if 
desired) and drivingly connected to a pulley 72 rotationally mounted to 
support plate 66. A drive belt 70 drivingly connects pulley 72 with a pair 
of pulleys 74, 76 that are also rotationally mounted to the support plate 
66. An appropriate shield 78 is attached to the support plate 66 to shield 
the moving pulleys and belt. 
Each pulley 74, 76 is drivingly attached to a drive shaft 80, 82, that 
extend through the support plate 66 into gear boxes 84, 86, respectively 
that are mounted to the shell 32 by known means such as bolting. A driven 
shaft extends at substantially a right angle from each gear box 84, 86 
through the end wall of the shell 32 and engage a drive shaft that drives 
a trommel. Thus, referring to FIG. 1 in particular, it will be seen that a 
driven shaft 88 extends inwardly inside shell 32 from gear box 84 and is 
attached to a trommel drive shaft 89 of trommel 28 by means of a collar 
90. Trommel 28 is thus driven by motor 68 through pulleys 72, 74 shaft 80, 
gear box 84 and shaft 88. A similar drive arrangement drives trommel 26. 
Referring briefly to FIG. 5 it will be seen that a driven shaft 91 extends 
through shell 32 from gearbox 86 into an open ended collar 92 that also 
receives the trommel drive shaft 93 of trommel 26. Both shafts 91 and 93 
may be held in place with set screws 94 as shown. A similar form of 
attachment may be used to drivingly connect drive shafts 88 and 89 to each 
other. 
Gear boxes 84 and 86 each have another stub drive shaft extending outwardly 
and downwardly therefrom. Thus, referring to FIG. 1, a stub shaft 95 is 
driven by gear box 84. Shaft 95 is attached to an intermediate shaft 96 
having universal joints 97 and 98 at each end thereof. Shaft 95 is 
attached to U-joint 98. U-joint 97 is attached to a driven stub shaft 100 
that is attached to and part of a gear box 102, which is mounted in any 
known manner, such as by bolting, to shell 30 of module 12. A right angle 
driven shaft 104 extends inwardly into shell 30 and is attached to a 
trommel drive shaft 106 of trommel 24 by a collar 105. A similar, though 
not shown drive arrangement is used to drive trommel 22 from a gear box 
108. The intermediate drive shaft 96 and the intermediate drive shaft used 
to drive gear box 108 are each covered with appropriate shielding members 
110, 112, respectively. 
A further protective shield is cover 114 that is bolted to the upper module 
14. 
Referring principally now to FIGS. 5-8 a trommel and an improved trommel 
cleaner will be described. Each trommel 22-28 has its own cleaner, all of 
which are substantially similar. Thus, only trommel 26 and the trommel 
cleaner 120 for trommel 26 will be described, it being understood that the 
trommels 22, 24, and 28 and the cleaners for trommels 22, 24, and 28 are 
substantially similar. 
Trommel 26 comprises a pair of end support rings 122, 124. Typically, 
though not shown, trommel 26 has longitudinally extending ribbing that 
extends between end support rings 122, 124 and cross bracing that extends 
across the interior of the trommel. Trommel 26 supports one or more screen 
panels 126 that may be attached to the end rings 122, 124 and the 
supporting structure in any known manner. A spout 128, which is attached 
to hopper branch 42, empties into the interior 129 of trommel 26. 
Referring briefly to FIGS. 5 and 6, it will be seen that the intake or 
input side of trommel 26 includes a wheel 130 that runs on a pair of 
spaced apart idler wheels 132, 134 that are rotationally mounted to the 
end wall of shell 32 by means of shafts 136, 138 respectively, which in 
turn are fastened thereto by a nut/bolt combination as best seen in FIG. 
5. Wheel 130 is attached to a larger diameter running wheel 140, which in 
turn is attached to end ring 122. As discussed earlier, trommel 26 is 
rotationally driven by trommel drive shaft 93, which is in turn attached 
to a spider 139, best seen in FIG. 6, that is attached by known means such 
as bolts to the end ring 124. 
Trommel cleaner 120 comprises a shaft 160 having a non-circular outer 
configuration that is square as shown in the Figures. Cleaner shaft 160 
mounts a plurality of individual flapper elements 162, which may be made 
of urethane or any other suitable material. Each flapper element 162 
comprises a hub 164 having a plurality of flappers or beaters 166 
extending outwardly therefrom that are substantially equally spaced 
therearound. As best seen in FIG. 8, the flappers 166 extend away from hub 
164 substantially tangentially thereto. Each flapper element has five such 
flappers 166 and thus the flappers 166 extend outwardly from the hub 164 
approximately seventy two degrees (7.degree.) apart and at an angle of 
approximately thirty degrees (30.degree.) relative to a radius of the hub 
164, the latter angle being variable within a range of about plus or minus 
five degrees (.+-.5 ). Hub 164 has an inner or central passage 168 that 
receives shaft 160. Central passage 168 is defined by the inner surface 
170 of the hub 164 and includes a plurality of indexing lobes 172 
extending inwardly from the inner surface 170 toward the center of the hub 
164. Referring to FIG. 8, it will be observed that the corners, that is, 
the longitudinally extending edges, 174 of shaft 160 are received between 
two adjacent indexing lobes 172 and that two lobes 172 bear against each 
side 176 of shaft 160. The flapper element embodiment shown in the Figures 
includes eight such indexing lobes. This enables each flapper element 162 
to be mounted to shaft 160 in eight different positions. Thus, adjacent 
flapper elements are mounted such that they are rotated approximately 
forty-five degrees (45.degree.) relative to the adjacent flapper elements. 
Since each flapper element 162 has five flappers 166 as shown, the 
flappers 166 of adjacent flapper elements are rotated approximately nine 
degrees (9.degree.) relative to each other. FIG. 8 illustrates a flapper 
element 162 in cross section as well as shows in phantom outline the 
positions of other flappers down the shaft 160 and illustrates that the 
flappers are displaced approximately nine degrees relative to each other 
such that the flappers extend outwardly from the shaft 160 in forty 
different positions according to the present embodiment. 
Consequently, the flappers 166 of the plurality of flapper elements 162 
mounted to shaft 160 engage the trommel 26 five times with each revolution 
of shaft 160 but they do not do so at the same time as is the case with 
prior art longitudinally continuous flapper designs. That is, prior art 
flapper or beater cleaners included five longitudinally continuous 
flappers mounted circumferentially to a shaft. With each revolution of the 
shaft, each flapper would strike the trommel once along the entire length 
of the trommel, thereby creating five separate but large torque spikes. 
With the present embodiment shown in the Figures, the flappers 166 are 
striking substantially continuously along the trommel, but because of the 
ability to index the flapper element 162 relative to the shaft 160, the 
torque spike is reduced by a factor equal to the inverse of the number of 
indexing positions, which in this embodiment would be 1/8; that is, only 
one eighth of the flappers are forcefully engaging the trommel at any 
point in time. It should be noted once again that to achieve this 
reduction the number of flappers must be odd if the number of indexing 
positions is even and odd if the number of indexing positions is even. 
Were the number of lobes and flappers both even the pattern would begin to 
repeat too quickly and the advantages of indexing, while still useful, 
would be less so. 
Dimensionally, in one embodiment, each flapper element hub 164 has a 
longitudinal extent within the range of about 21/2 inches to about 31/2 
inches, and preferably is about three inches. The flappers 166 have a 
width equal to that of the longitudinal extent of the hub and a length of 
about 2 inches to about 21/2 inches. 
It will be noted that in the present embodiment as shown in the Figures 
that each flapper element has an odd number of flappers 166 and an even 
number of indexing lobes 172. Generally, the indexing and torque reduction 
provided by the present invention can be achieved by any combination of 
odd and even numbers of the lobes and flappers, though preferably the 
numbers of lobes and flappers would not be multiples of each other since 
that would reduce the benefits of the ability to index the flapper 
elements 162. That is, the number of flappers could be even and the number 
of indexing lobes could be odd and the torque reduction provided by the 
present invention will be achieved. Having both the number of lobes and 
the number of flappers be even, however, would provide for a rapid 
repetition of the positions of the flappers and therefore would not 
provide the dramatic torque reduction provided by the present invention. 
Similarly, where the number of flappers and lobes are multiples of each 
other, such as three and six or five and ten, the benefits of indexing 
will also be reduced. 
The circumferential spacing of the flappers 166 about shaft 160 is shown in 
FIG. 8, thereby providing an indication of the reduction in the length of 
trommel being cleaned by the trommel cleaner at one time. Again, in the 
prior art, the entire longitudinal length of the trommel would be wiped by 
a flapper at one time. With the present invention, only one eighth of the 
trommel is being wiped at a time. The torque spike is therefore reduced by 
that same factor. 
The reduction of the torque spike has consequences for the overall 
structure and configuration of the sizer 10. First is that the flapper 
trommel cleaner 120 can be driven by a friction wheel rather than 
requiring a separate chain, belt, or electric drive. Thus, as seen in 
FIGS. 5 and 6 the trommel cleaner 120 is mounted for rotation within the 
shell 32. More specifically, shaft 160 is rotationally mounted to a pair 
of arms 178, 180. Arms 178, 180 are in turn each mounted to a torsion 
block 182. Torsion block 182 is used to apply tension to the trommel 
cleaner 120 such that the flappers 166 forcefully engage the trommel. 
Torsion block 182 is attached to an inwardly extending flange 184, which 
is attached to the interior of the shell 32. Arms 178, 180 each engage a 
stop block 194 that is provided to limit the movement of the arms 178, 180 
downwardly in the direction of the trommel 26. 
More specifically yet, shaft 160 is mounted to a pair of friction wheels 
186, 188, at each end thereof. Friction wheel 186 rotationally engages 
running wheel 140 formed at the end of trommel 26. Thus, as trommel 26 
rotates counter-clockwise as indicated by arrow 190, trommel cleaner 120 
will be rotated in a clockwise manner as indicated by arrow 192 through 
the frictional engagement of friction wheel 186 with running wheel 140. 
The flappers 166 of the flapper elements 162 will wipe across the trommel 
screens of trommel 26, dislodging particulate matter that may be lodged in 
the screen apertures. 
As noted, in the embodiment shown, each flapper element 162 includes a 
plurality, here five, of lobes 172, that extend the entire longitudinal 
extent of the hub 164. The lobes 172 need not extend the entire length, 
though doing so helps strengthen the flapper element and spreads the 
stress felt by the lobes across a greater length. The lobes 172 have a 
substantially hemispherical cross section that transition into the inner 
surface area between the lobes with a somewhat wedge-shaped portion. Other 
cross sections may be used if desired. The inner surface 170 between the 
lobes 172 is substantially smooth and may be somewhat flat; that is, the 
surface 170 between the lobes 172 need not form a circular surface 
relative to the longitudinal axis of the hub 164. 
The present invention having thus been described, other modifications, 
alterations, or substitutions may now suggest themselves to those skilled 
in the art, all of which are within the spirit and scope of the present 
invention. It is therefore intended that the present invention be limited 
only by the scope of the attached claims below.