Note: Descriptions are shown in the official language in which they were submitted.
1045495
The invention relates to a combine-harvester whic~ :
is provided with sensing means ~or monitoring the
effectiveness o~ harvesting operations so that the speed
oi the combine-harvester can be maintained at or near
its optimum value.
In the operation of a combine-harvester, as it
~oves along a iield o~ cereal grain-bearing plants,
cut plants are fed to a threshing d~um where straw is
separated ~rom chafi and grain. The straw is passed
to straw walkers which convey it to the rear of the
combine-harvester where it is allowed to iall back
onto the iield and the chaif and grain are passed over
grain sieves through which air is passed irom a ~an to
blow the chaif irom the grain. The grain is thus
enabled to pass through the sieves and the chaif which
is not carried away by the stream oi air irom the ian
is allowed to discharge over the rear end oi the sieves.
In ~eneral, if the sieves and the fan of a combine-
harvester are adjusted so that grain losses over the
rear end oi the seives and grain losses in the air
stream rrom the fan are reduced to acceptable ievels,
then over the range o~ normal driving speeds o~ a
com~ine-harvester, the amount of grain fed to the straw
walkers and subsequently discharged with the straw ialls
within acceptable limits. ~Iowever, as soon as the speed
oi the combine-harvester rises above a critical value
at which the threshing drum becomes over-loaded the grain
losses from this source increase at a substantial and
unacceptable rate as a result oi imper~ect operation
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of the over-loaded threshing drum.
In a combine-harvester provided with sensing
mealls Dor ~onitoring the effectivensss of harvestin~
operations, sensors are used to measure the incidence
of grain in the straw and chaff discharged from the
combine-harvester. Thus, in a conventiona] form of
this apparatus, two acoustic sensors are respectively
mounted at the rear end of the straw walkers and at a
position, for example: the mid-position, between the
; 10 ~ rear end of tne graln sieves, and the~co~r~ of the
stream air used to blow the chaff ~rom the grain. -
To obtain optimum results, the combine-harvester
is driven at normal harvesting speed through a field
of grain-bearing plants and the sieves and the fan are
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adjustea untll, onqina~pctio~ of the straw discharged
from the rear of the combine-harvester, it is clear ' ~-
that grain losses have been reduced to an acceptable ! -
level. The indication provided by the sensor disposed
to the rear of the sieves under these conditions may
then be used as a first datum value against which
subsequent indications provided by this sensor can be
compared so as to indicate malfunction of the sieves
or maladjustment of thc sieves or the fan. The speed
of the combine-harvester is then progressively increased
until the sensor mounted at the rear end of the straw
walkers indicates an excessive rate of increase in grain
loss. Thus, by noting the indications given by the
sensor at the rear end of the straw walkers, at the
different speeds of operation, it is possible to note
3~ a second datum value correspondin~ to the highest speed
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at ~Yhich the co~bine~harvester can travel without
causlng excessive grain loss from the straw wallcers as
a result o~ over-loading of the threshillg drum
Theoretlcally, once this second datum value has been
noted, for op~ration in a particular field on a
particular dny under particular climatic conditions,
the speed of the combine-harvester can be maintained as
high as possible by ensuring that the speed is only
reduced when the sen~or at the rear oi the straw walkers
gives an indication in excess of the second datum value.
!~ Unfortunately, visual assessments oi grain loss,
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i; by inspecting the straw discharged at the rear Or the
~- combine-harvester, are notoriously unreliable and so it
is dif~icult to make the preliminary adjustment of the
~` sieves and the fan necessary to obtain optimum harvesting
results. Moreover, it has been iound that the sensor
disposea to the rear o~ the sieves cannot be used
~- very effectively to assist in this preliminary adjustment. -
; Thus, when the fan is improperly set to provide too
high an air ilow through the sieves, the detector to the
rear o~ the sie~es may give an indication consistent
with a low incidence of grain entrained with the chaff
; bein~ discharged from the rear end of the sieves, whereas
- an excessive amount of grain, entrained in the un-
necessarily high flow of air ~rom the fali, is blown
from the rear of the combine-harvester. Equally, i~
the ian is improperly set to provide too low an air
flow through the sieves, the detector disposed to the
rear oi the sieves may give an indication consistent
with a low incidence o~ grain even thou~h the sieves are
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improperly set and excessive grain is being carried over the
rear end of the sieves.
It is therefore an object of the present inVention to
provide a combine-harvester having grain-discharge detector
means which facilitate adjustment of the grain sieves and the
fan so as to enable the optimum settings to be more readily
ascertained.
According to the invention, there is provided a com-
bine-harvester comprising, a vehicle having a driver's cabin
and front and rear ends for receiving cut grain crop and dis-
i charging straw, respectively, cutting means disposed at the
,~ front end of the vehicle for cutting grain crop, a threshing
drum for separating grain from straw, conveyor means for feeding
cut grain crop from the cutting means to the threshing drum,
1 straw walkers extending upwardly from the threshing drum
- towards the rear end of the vehicle and having a rear end from
which straw from the threshing drum is discharged under gravity,
adjustable sieve means, for separating chaff from grain, extend-
ing towards the rear end of the vehicle and having a forward end
disposed below the level of the threshing drum, for receiving
grain from the threshing drum, and a rear end over which chaff
separated from the grain received from the threshing drum is
discharged under gravity, a hood mounted on the rear end of the
vehicle and co-operating with the straw walkers and the sieves
to define an air flow path, an adjustable output fan for
providing an air flow which passes through the sieVe means, to
facilitate the separation of chaff from grain on the sieve
means, and along the flow path to the rear end of the vehicle,
two grain-discharge detectors respectively mounted below the
rear end of the straw walkers and the rear end of the sieve
means to detect grains in the straw and chaff discharged at
the rear end of the vehicle, an additional grain-discharge
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detector mounted in the air flow path at the rear end of the
vehicle to detect grains entrained in the air flow from the
fan, and metering and display means mounted in the driyer~s
cabin and connected to the two grain-discharge detectors and
to the additional grain-discharge detector,
Thus, with the combine-harvester provided with three
or more grain-discharge detectors, in accordance with the
invention, it is possible to connect the sensors to a metering
and display unit disposed in front of the driver so that the
driver can see the effect, in terms of grain loss, of any
adjustment to the setting of the sieves or of the fan. Con-
sequently, apart from the more precise indication of the source
of any increase in grain loss which may occur during harvesting,
the chief advantage of the present invention over other existing
systems is that the use of three or more sensors, in the
positions specified, enables the sensors
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to be used to obtain o~timum settings of the sieves
and the fan at th~ c~mmellcement of harvesting.
An embodiment of the invention is hereinafter
described, by way of example, with reference to the
accompanyin~ drawing, which is a schematic side
elevation of a combine-har~ester fitted with three
acoustic, grain-d1scharge detectors.
As shown in the drawing, cutting means 10 are
provided at the front end of the machine and conveyor
mear.s 11 disposed within the support frame 12 of the
cutting means 10 ~eed cut plants to a threshing drum
13 where straw is separated from grain and chaff and
- delivered to straw walkers 14 which carry the straw
towards the rear oi the machine while disturbing the
straw so as to shake loose and dislod~e any graln which
has been fed on to the straw walkers.
- Grain and chaff ~hich is separated from the straw
by the threshing drum 13 1s fed to adjustable sieves c
15 and air irom a fan 16 is blown through the sieves 15
and separates the chaff from the grain so that the
grain is able to pass through the sieves 15 while the
- chaff is collected on the sleves 15 so as to flow over
the rear end of the sieves 15.
; The three acoustic detectors 17, 18 and 19 are
mounted inside or adjacent a hood 20 enclosing the rear
endY of the straw walkers 1~ and the sieves 15 of the
dischar6e end of the combine-harvester so that two detec-
tors 17 and 18 are disposed adjacent the rear ends of the
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straw walkers 14 and the sieves 15 and extend across
substantially the whole width of the straw walkers and
the sieves in the paths of the straw and cha~f while the
third detector 19, which extends across substantially
the entire width of the hood 20, is disposed in the
path of the air ~rom the fan 16, between the path of
the stra~ and the path of the chaff discharged from
the rear end of the sieves. Electrical leads (not
shown) connect the three detectors 17, 18 and 19 to a
metering and display unit 21-positioned in~front Or the
driver'sca~in 22.
By adjusting the metering and display unit 21 so
that it provides readings from the three detectors 17,
18 and 19, in turn, it is possible to adjust the fan
~ and the sieves 15, so that the metering and display
unit 21 provides an indication of the effect of these
adjustments in addition to showing how the speed of the
combine-harvester varies from the optimum speed.
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