Note: Descriptions are shown in the official language in which they were submitted.
20~7203
~ PATENT
--1--
A CLEANING SYSTEM FOR A COMBINE
Field of the Invention
The present invention relates to combines
and, more particularly, to a combine cleaning system
including an elongated cleaning fan arranged in
combination with an air plenum to increase the
efficiency of separation of grain from material other
than grain.
Background of the Invention
Combines are old and well known in the art.
They are available in various designs and models to
perform the basic functions of harvesting, threshing
and cleaning of grain or other crop materials.
A typical combine includes a crop harvesting
apparatus which reaps planted grain stalks and then
feeds the grain stalks to a separating or threshing
apparatus. Preferably, the threshing apparatus
includes a power-driven rotor mounted inside a
stationary cylindrical threshing cage. The rotor
threshes and separates the grain from the material
other than grain. In such a combine, which has been
available for a number of years, the grain is
threshed several times repeatedly, but gently, as it
spirals around the rotor and passes through openings
in the threshing cage. Essentially, most material
other than grain stays within the threshing cage and
is directed out the rear end of the combine.
While the threshing apparatus acts to
separate a substantial portion of the crop or grain
from the material other than grain, some chaff or
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straw is directed out through the openings in the
cage along with the grain and a further cleaning or
separating action is required. Further separation is
normally achieved in a cleaning section.
The cleaning section includes oscillatng
- cleaning sieves. The cleaning sieves are located
below the threshing cage to receive the grain and
other material expelled from the cage. The
oscillation of the sieves arranges the material in a
crop mat or veil on top of the sieves. By forcing a
stream of air upwardly through the sieves, chaff,
straw and other lighter material in the crop mat is
separated from the heavier grain and is directed out
through the end of the combine by the air flow. The
heavier seeds or grain fall through the sieves into a
collector.
With the increased power and output demands
of modern grain combines, cleaning section capacity
has become a limiting factor. The most readily
achieved method of increasing combine capacity is by
increasing the width of the combine and the sieves to
spread the crop material across a wider area and in a
thinner veil. Increasing the width of the cleaning
sieves, so as to increase cleaning section capacity,
also involves having to modify the air flow across
the increased size of the cleaning sieves. The
inherently uneven air distribution of known cleaning
~ fans is accentuated with an increase in the width of
the cleaning sieves.
The problem of increased air requirements
could, of course, be diminished by increasing the fan
diameter in proportion to its increase in its width.
This proposed solution, however, is not practical.
An increase in fan diameter would necessitate an
increase in the height of the combine. The maximum
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overall height of the machine, however, is dictated
by considerations such as clearance under bridges and
barn doors. Another -reason why the diameter of the
fan cannot be increased is that a casing surrounding
the fan is the lowest protrusion beneath the combine
~ and, thus, it defines the ground clearance. For
proper maneuverability of the combine, it is
necessary to maintain adequate ground clearance. The
overall height and ground clearance of combines have
been reached within their practical limits.
Therefore, increasing the diameter of the fan is not
a feasible solution to the problem.
One attempt at solving the problem of
providing increased air requirements involves a split
fan design. With such a design, two fans are mounted
on a common shaft. This is an expensive design.
Moreover, increases in the width of the cleaning area
likewise requires an increase in the fan's length
resulting in non-uniform flow output along their
length. A non-uniform air flow will be detrimental
to proper operation of the cleaning system.
- Blower devices commonly known as
transverse-flow blowers have a blower wheel which
includes a plurality of elongated blades arranged in
a cylindrical pattern such that the blower wheel has
a hollow interior. The stream of air produced by
transverse-flow blowers is relatively thin. Since a
~ combine cleaning system requires a relatively thick
stream of air, the use of transverse-flow blowers in
combine cleaning system is not a natural adaption.
Transverse-flow blowers are, however,
appealing for this purpose because they conserve
space and produce a wide uniform stream of air. In
such a device, a fan rotor having a series of blades
is rotatably arranged within a fan wrapper which
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encompasses and is closely spaced about the fan
rotor. Relatively close tolerances and dimensions
are required between the fan wrapper and fan rotor to
achieve proper operation of the blower.
Because the blower device on a combine is
_ - disposed close to the ground over which the combine
moves, the fan rotor, the fan wrapper, or both often
engage rocks or other debris causing damage which
requires maintenance to the blower. Repeated removal
and replacement of such parts often modifies the
relationship between the fan wrapper and fan rotor in
a manner adversely effecting the performance of the
cleaning system. Thus, the overall performance of
the combine is often times adversely effected and
production falls below an expected level.
Summary of the Invention
In view of the above, and in accordance with
the present invention, there is provided an improved
cleaning system for a combine. The cleaning system
includes a transversely mounted and elongated
cleaning fan having a relatively large inlet area
because there is no wrapper which surrounds or
interferes with fan performance.
More specifically, there is provided a
cleaning system for a combine having a crop
harvesting apparatus attached to a forward end of the
combine. A separating apparatus, enclosed within a
housing, is arranged in crop receiving relation to
the harvesting apparatus. Cleaning sieves are
arranged in crop receiving relation with the
separating apparatus.
One aspect of the present invention concerns
an elongated transverse cleaning fan rotatably driven
about a fixed axis. The fan is transversely mounted
on the combine beneath the separator apparatus and
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forward of the cleaning sieves. The fan includes a
plurality of peripherally disposed and spaced apart
blades for developing an air stream which is directed
toward the cleaning sieves.
Another aspect of the present invention
__ - concerns an improved air plenum for directing a
forced flow of air from the fan rearwardly up through
the cleaning sieves to blow chaff toward the rear end
of the combine. Albeit extends parallel to and along
the entire length of the fan, the air plenum does not
encompass or surround the fan.
In accordance with the illustrated
embodiment, the air plenum includes vertically
spaced, upper and lower air directing baffles
defining an air inlet which opens to the front of the
combine. The upper air directing baffle extends
rearwardly and upwardly from a forward edge which is
positioned adjacent a rear peripheral edge of the
fan. The lower air directing baffle includes a
substantially horizontal first section extending
beneath and in vertically spaced relation with the
fan. The lower air directing baffle further includes
a second section. The second section is joined to
the first section and extends rearwardly therefrom at
an acute angle to the horizontal. The first and
second sections are joined at a location in
substantial vertical alignment with the rearmost
peripheral edge of the fan.
The first section of the lower air directing
baffle preferably originates forwardly of the
transverse fan axis. By such construction, the
inwardly drawn air is directed rearwardly in an
advantageous manner.
The upper air directing baffle of the air
plenum preferably includes a substantially horizontal
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first section and a second section. The second
section is joined to the first section and extends
rearwardly at an acute angle to the horizontal. The
first section of the upper air directing baffle
originates adjacent a rear peripheral edge of the fan
-- - and is disposed in a relatively close vertical
relationship to the rotational axis of the fan.
The cleaning fan is mounted on the combine
to provide a substantially uniform stream of air
across the cleaning sieves of the combine regardless
of their width. The cleaning fan is illustrated as
having the fan blades symmetrically slant or curve
toward a center portion of the fan. The resultant
flow of air off the blades is directed outward toward
the fan ends and rearward in a manner improving fan
performance by lessening end effects of the fan and
thereby providing a more uniform stream of air across
the cleaning sieves. It has been observed that
slanting of the fan blades furthermore facilitates a
reduction in the operating noise (sound) level of the
fan. Accordingly, higher fan speeds can be used to
increase the output flow of air from the fan without
concern over environmental noise pollution.
Alternatively, cone-shaped caps are secured at
opposite ends of the cleaning fan to draw air from
the fan center in a manner reducing the end effects
of the fan.
The cleaning fan and air plenum cooperate to
produce air velocities which are relatively high
across the full length of the sieves to keep the crop
mat open and suspended. Such air velocities,
however, are not so high that clean grain is
prevented from penetrating the cleaning sieves or is
blown out the rear end of the combine and lost.
3~ Because there is no housing or closely wrapped casing
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about the fan, the present invention provides an
easily maintained, simple structure of relatively low
cost and which produces a beneficial air cleaning
flow leading to maximum recovery of grain.
Other features and advantages of the present
--- ~ invention will become readily apparent from the
following detailed description, the appended
drawings, and the accompanying claims.
Brief Description of the Drawings
FIGURE 1 illustrates a perspective view,
partially broken way, of a combine;
FIGURE 2 is a cross sectional view showing a
separating apparatus and cleaning system of the
combine;
FIGURE 3 is a side elevational view taken
along line 3-3 of F IGURE 2;
FIGURE 4 is a side view of a modified
transverse cleaning fan; and
FIGURE 5 is a side view of another modified
transverse cleaning fan;
FIGURE 6 iS a side view of still another
modified transverse cleaning fan;
FIGURE 7 iS a perspective view of the
cleaning fan illustrated in FIGURE 6;
FIGURE 8 iS an enlarged side view of a
fragmentary portion of the cleaning fan illustrated
in FIGURE 6; and
FIGURE 9 is a sectional view taken along
line 9-9 of FIGURE 8.
Detailed Description
While the present invention is susceptible
of embodiment in various forms, there is shown in the
drawing presently preferred embodiments of the
invention which are hereinafter described, with the
understanding that the present disclosure is to be
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considered as an exemplification of the invention,
and is not intended to limit the invention to the
specific embodiments illustrated.
Referring now to the drawings, wherein like
reference numerals indicate like parts throughout the
_ - several views, there is shown in FIGURE 1 a
self-propelled combine 10. At its front end, combine
10 is provided with a crop harvesting apparatus or
header 12 which can be of any suitable design and an
operator's station 13. The combine is operatively
powered by an engine (not shown) suitably housed
therein to provide driving power for the combine.
The transfer of rotation and power from the engine to
the various driven components of the combine is of a
conventional nature and could include fixed or
variable belt or chain drives which are not shown for
purposes of clarity.
The crop harvesting apparatus 12 cuts and
directs crop material into a separating or threshing
apparatus 14. Separating apparatus 14 is enclosed in
a housing 16. In its preferred form, and as best
seen in FIGURE 2, the separating apparatus includes
-a threshing cage 17. Located within the threshing
cage 17 is a coaxially disposed rotor 18. Rotor 18
directs crop material to be threshed from an inlet
end 15 of the separating apparatus toward an exit end
19 .
Between the inlet and exit ends of the
separating apparatus 14, crop or grain is threshed
several times repeatedly, but gently, as it spirals
around the single large diameter rotor 18 and passes
through the threshing cage. Disposed about the rotor
is a simple system of concaves 20 and separating
grates 22 which, through the action of the rotor and
centrifugal force, act to separate grain from the
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g
majority of material other than grain and deliver
such material to a pair of vertically spaced apart
cleaning sieves 24 and 26. In the embodiment shown,
augers 28 move grain to the cleaning sieves 24 and 26.
The sieves 24 and 26 are oscillated to
_ - separate the grain from material other than grain.
The oscillation of sieves 24 and 26 arranges the
materials disposited thereon in a relatively large
crop mat or veil extending across substantially the
entire sieve. The heavier grain falls through the
sieves 24 and 26 to a clean grain collector 30.
Auger 31 directs the grain from collector 30 into a
hopper (not shown).
Material which is too large to pass through
the grates 20 and concaves 22 is propelled rearwardly
by rotor 18. A beater element 32, disposed
rearwardly of separating apparatus 14, acts upon the
material discharged from rotor 18. Suffice it to
say, beater element 32 propels crop residue from the
rear of the rotor and throws it back for discharge
from the rear end of the combine.
A salient feature of the present invention
concerns a cleaning fan assembly 40 arranged in
combination with the cleaning sieves 24 and 26.
Cleaning fan assembly 40 includes an elongated
transverse cleaning fan 42 and an air plenum 44.
Fan 42 extends transversely across
substantially the entire width of the combine 10.
More specifically, fan 42 is transversely mounted on
the combine beneath the separator apparatus 14 and
forward of the cleaning sieves 24 and 26. An
elongated shaft 45 defines a rotational axis 47 for
fan 42. Opposite ends of shaft 45 are rotatably
received in bearing assemblies 46 fixedly carried by
opposed end walls 48 of housing 16. Housing 16
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effectively closes the sides of fan 42.
Fan 42 further includes a plurality of
closely spaced forwardly curved, peripherally
disposed blades 50. As seen in FIGURE 2, blades 50
define an elongated opening 52 through the center of
-- the fan. As best seen in FIGURE 3, a series of
axially aligned support plates 54, which are
connected to shaft 45, circumferentially arrange and
support blades 50.
Further mounted on shaft 45 is a pulley 56
which forms part of a variable speed fan drive. The
variable speed fan drive permits the operator to
adjust fan speed without having to leave the
operator's station 13.
Air plenum 44 extends parallel to and along
substantially the entire length of the fan 42 for
directing air discharged from the fan toward the
cleaning sieves. As best illustrated in FIGURE 2,
the air plenum 44 opens to the front end of the
combine and provides a large inlet area to the fan
because there is no wrapper which surrounds or
interferes with fan performance. As illustrated, the
air plenum 44 includes upper and l~wer air directing
baffles 60 and 62, respectively. The upper and lower
air directing baffles 60 and 62 are formed from a
material such as sheet metal that is impervious to
the passage of air.
- Upper air directing baffle 60 defines a
leading edge 64 which is positioned closely adjacent
a rearmost peripheral edge of fan 42. Baffle 60
extends rearwardly and upwardly from its leading edge
64. Preferably, baffle 60 includes first and second
sections 66 and 68, respectively. First section 66
of baffle 60 extends substantially horizontal. More
specifically, the first section 66 of baffle 60
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originates adjacent a rear peripheral edge of the fan
and is disposed in a relatively close vertical
relationship with the axis 47 of fan 42. The second
section 68 of baffle 60 is joined to the first
5 section 66 and extends rearwardly at an acute angle
to the horizontal.
The lower air directing baffle 62 includes
first and second sections 70 and 72, respectively.
The first section 70 extends substantially horizontal
10 beneath and in vertically spaced relation with the
fan to define an inlet opening 74 which extends
across the length of the fan. Preferably, the first
section 70 of the lower air directing baffle 62
originates forwardly of the transverse fan axis.
The second section 72 of baffle 62 is joined
to the first section and extends rearwardly at an
acute angle to the horizontal toward, and may be
joined to, collector 30. The first and second
sections 70, 72 of baffle 62 are joined at a location
in substantial vertical alignment with the rearmost
peripheral edge of the fan. By such construction,
overflowing grain from collector 30 will drop out the
forward end of the air plenum rather than being
caught up in the fan's operation.
To avoid the grain from collecting on one
area of the sieves, it is important to evenly
distribute cleaning air flow across the entire width
of the sieves. FIGURE 4 illustrates one embodiment
of a fan 142 which is designed to uniformly
distribute air flow across the entire width of the
cleaning sieves. While it is contemplated that fan
142 is to be used with an air plenum arrangement as
described above, it will be appreciated that features
of the fan described hereinafter will likewise
facilitate an increase in combine efficiency with
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other arrangements capable of directing air toward
the cleaning sieves.
Fan 142 is rotatably mounted in
substantially the same manner as was fan 42 and
extends transversely across substantially the entire
_ ~ width of the combine 10. Fan 142 includes an
elongated shaft 145 defining a rotational axis for
the fan 142. Fan 142 further includes a plurality of
blades 150, with each blade preferably having a
generally curved cross-sectional configuration. A
series of axially aligned support plates 154, which
are connected to shaft 145, support blades 150. A
hollow conically shaped cap 151 is fixedly carried at
opposite ends of the fan 142. Each cap 151 is formed
from a material such as sheet metal that is
impervious to the passage of air.
Another embodiment of a fan 242 is
illustrated in FIGURE 5. Fan 242 is rotatably
mounted in a manner substantially similar to the
mounting for fan 42 and extends transversely across
substantially the entire width of the combine 10.
Fan 242 is preferably arranged in ccmbination with a
suitable apparatus for directing air discharged from
the fan toward the cleaning sieves. An elongated
shaft 245 defines a rotational axis for fan 242. A
series of axially aligned support plates 254, which
are connected to shaft 245, support a plurality of
- blades 250, with each blade having a generally curved
cross-sectional configuration. Blades 250 are
peripherally arranged in a closely spaced
relationship relative to one another and define an
opening extending through the center of the fan 42.
Each of the blades 250 symmetrically curve from
opposite ends of the fan toward the longitudinal
center of the fan.
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Still another embodiment of a fan 342 is
illustrated in FIGURES 6 through 9. Fan 342 is
rotatably mounted on the housing 16 and is driven in
substantially the same manner as fan 42. Fan 342
extends transversely across substantially the entire
_ ~ width of combine 10 and is arranged in combination
with a suitable apparatus for directing air
discharged from the fan toward the cleaning sieves.
Fan 342 includes a shaft 345 which supports
and defines a fixed rotational axis for the fan. A
series of support plates 354 are connected in axially
spaced relation to the shaft 345. A plurality of
elongated, spaced apart fan blades 350 pass through
the axially spaced support plates 354 and are
peripherally disposed about the fan 342. In a
preferred form, each of the fan blades 350 have a
generally curved cross-sectional configuration.
As illustrated in FIGURES 6 and 7, each fan
blade 350 slants or tapers toward a longitudinal
center portion of the fan. The resultant flow of air
off the blades 350 is directed outward toward the fan
ends and rearward in a manner improving fan
performance by lessening end effects of the fan and
providing a generally uniform air distribution across
the cleaning sieves. Slanting of the fan blades 350
furthermore facilitates a reduction in operating
noise (sound) level of the fan. Accordingly, higher
fan speeds can be used to increase the output flow of
air from the fan without concern over environmental
noise pollution.
As illustrated in FIGURES 8 and 9, the fan
blades 350 and support plates 354 are releasably
interconnected such that replacement of any blade
re~uires only a minimum amount of time. Preferably,
the fan blades 350 are fabricated from sheet steel.
-
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Each support plate 354 defines a plurality of
peripherally arranged slots 356 through which the fan
blades 350 pass. As illustrated in FIGURE 9,
opposite ends of each fan blade are provided with an
inwardly directed groove 358 provided along a
longitudinal edge of a blade and having a thickness
generally equal to the thickness of a support plate
354.
During fan fabrication, the angular
relationship between adjacent support plates provided
between a fan end and the fan center is adjusted such
that the slots 356 in the axially spaced support
plates 354 which support a common blade passing
therethrough are angularly offset relative to each
other in a progressive manner extending toward the
middle of the fan such that each blade slants toward
the middle of the fan. The angular offset between
the slots 356 causes the blade to be simultaneously
or conjointly twisted. The twisting action of the
blade when combined with its slant toward the fan
center causes the groove 358 in the blade to
-releasably engage and lock with a support plate 354
and maintain such engagement under the influence of
the twist tension in the blades~ As will be
appreciated, replacement of a single blade requires
only the overcoming of the twist tension in the blade
and then removal of the blade through the slots from
- the fan 342.
Upon rotation, cleaning fan 42 draws air in
along the full length of the fan about its outer
circumference. The air hits the blade ring twice for
a single rotation of fan 42 and is then forced out
into the air plenum 44. The air plenum directs a
forced flow of air from the fan rearwardly up through
the cleaning sieves 26 and 28 to blow chaff toward a
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rear end of the combine. The above described design
of the air plenum positions the vortex, generated by
the rotating fan, to-create a beneficial air flow.
The alternative fan embodiments shown in
5 FIGURES 4, 5, and 6 through 9 diminish the end
effects of the fan and provide a generally uniform
air flow output across the width of the fan. More
specifically, with respect to FIGURE 4, as the air
passes through the blade of fan 142, a vacuum is
created in the cone caps 151. This vacuum draws air
towards the ends of the fan in a manner diminishing
end effects and provides a more uniform air
disbribution to the cleaning sieves.
In the embodiment shown in FIGURES 5 and 6
through 9, the fan blades are symmetrically curved or
slanted toward a center portion of the fan. This
curve or slant of the fan blades forces the air from
the center of the fan, outward towards the ends
whereby providing a more uniform air distribution.
This forcing effect will happen twice on each blade
on a single rotation of the fan. After air enters
the blade it will move across the opening extending
through the center of the fan parallel to the fan's
rotational axis and be forced out toward the ends of
the fan. As the air passes through the fan, the
curving or tapering blades will again act on the air
further forcing it sideways toward the ends of the
fan in a mannner diminishing end effects. The
slanting of the blades furthermore facilitates a
reduction in the operating noise level of the fan.
The advantages for this type of cleaning
system is that a uniform velocity profile is created
across the fan and, therefore, an unlimited width
possibility exists for the fan. Therefore, the width
of the cleaning section and, thereby, the capacity of
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the combine can be increased without adversely
effecting the performance of the combine. Because
the fan is not enclosed within a wrapper, the fan of
this invention is simpler in structure and has less
components. There are no side inlets for the fan
_ and, therefore, the fan is not affected by side
winds. Moreover, the fan may be designed much more
compact and has a substantially lower profile aiding
to the design of the combine.
Thus, there has been described numerous
modifications or variations which can be effected
without departing from the true spirit and novel
concept of the present invention. It will be
appreciated that the present disclosure is intended
lS as an exemplification of the invention, and is not
intended to limit the invention to the specific
embodiments illustrated. The disclosure is intended
to cover by the appended claims all such
modifications as fall within the scope of the claims.
