Note: Descriptions are shown in the official language in which they were submitted.
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SEEDER CALIBRATION APPARATUS AND METHOD
This invention is in the field of agricultural seeders and in
to particular the calibration of such seeders to ensure proper
application rates.
BACKGROUND
Air-seeders are commonly used in agriculture for seeding,
fertilizing and so forth where an agricultural product is
inserted into the ground or applied to the ground surface. An
air-seeder generally comprises a tool-bar, with furrow
ao openers, spreaders or the like mounted thereon for receiving
seed, fertilizer, or other agricultural products and
delivering same into or on the ground. The tool-bar is
connected to an air-seeder cart which carries two, three, or
more tanks or compartments for carrying different agricultural
products. Metering devices on each tank meter the product at
the desired rate for each product into an air-stream for
delivery to the furrow openers, spreaders or the like mounted
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on the tool-bar.
The metering devices are generally rotating augers, rotors or
the like which deliver a given amount of material for each
revolution of the device. The metering devices are driven by
to a ground wheel such that the metering device turns
proportionally to the ground wheel. In this manner the speed
of the air-seeder can vary and the application rate will
remain substantially constant. An electric clutch or the like
allows the operator to turn the metering devices on or off.
Application rates for agricultural products vary from 5 pounds
per acre or less, for example for canola, to 300 or more
pounds per acre for fertilizer. The density of an
agricultural product can vary significantly. For example when
2o seeding wheat, the density can vary from 55 to 65 pounds per
bushel. Similarly, seeds today are often coated with chemical
protectants and so forth which can greatly affect the density.
In order to overcome these variations and obtain accurate
application rates for the particular product, it is necessary
for the metering device to be calibrated using the particular
product actually being applied.
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s In the present state of the art, this calibration is the most
difficult for products such as canola that are applied at low
rates because it is a lengthy and often onerous procedure to
manually obtain a sample large enough to make scale errors
insignificant.
to
The state of the art calls for an operator manually turning a
crank attached to a metering device until an adequately sized
sample of the product located in the corresponding tank is
obtained in a catch box positioned under the metering device
is to receive the product. The operator counts the number of
turns, and uses a chart to find the area of ground that
corresponds to the number of turns of the metering device.
The product in the catch box is then weighed and the rate per
acre is calculated. For example, to obtain a satisfactory
zo sample of 20 pounds of canola it may be necessary to crank the
metering device the equivalent of 4 acres or more. It is also
desirable to crank the metering device at a constant speed to
simulate field conditions as closely as possible.
2s Another less physically demanding calibration method calls for
securing the catch boxes in position and driving the air-
seeder cart forward with the metering devices turning,
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catching the different products until adequately sized samples
are obtained. This often requires the operator to stop the
tractor, climb out and visually check the levels in each of
the catch boxes several times during a single calibration run.
Where there are large differences in application rates for
to the products, the operator will also have to stop the metering
device for the high application rate product, and continue
driving the air-seeder and checking to see if the low
application rate product sample is adequate.
i5 Present day air-seeders often have three or more metering
devices, each of which must be calibrated at sometimes widely
varying application rates. Because of the present
requirements for calibrating metering devices, farmers often
believe that they have neither the time nor the energy to
20 obtain the large samples that are required for accurate
calibration and subsequently often experience significant
application errors. Because the costs of some of these
products are very high, the application errors can result in
significant monetary waste.
SUMMi~tY OF THE INVENTION
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It is an object of the present invention to provide a system
and method for calibrating metering devices on an air-seeder
cart that is quickly accomplished with little effort.
io It is a further object of the present invention to provide
such a system and method that displays to an operator accurate
application rates over a broad range of application rates.
The present invention provides a system for performing an air-
i5 seeder calibration procedure simultaneously on at least first
and second rotating metering devices mounted on an air-seeder
cart, the air seeder cart comprising a ground drive for
rotating the first and second metering devices in proportion
to a speed of travel of the air-seeder cart along the ground,
2o each metering device operatively connected to a separate tank
for dispensing product from the tank, each metering device
dispensing a substantially constant amount of product for each
revolution thereof.
2s The system comprises a calibration motor operative to
rotationally drive the first and second metering devices
simultaneously such that product is dispensed from each
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s metering device while the air-seeder cart is stationary. A
first meter control is operative to stop rotation of the first
metering device, thereby terminating a first calibration
procedure for the first metering device, while allowing the
second metering device to continue rotating. A second meter
to control is operative to stop rotation of the second metering
device, thereby terminating a second calibration procedure for
the second metering device, while allowing the first metering
device to continue rotating. Thus the operator has
independent control of the metering devices, so that products
is with a large variation in application rates may be
accommodated in either tank. The first and second meter
controls are located on the air-seeder cart.
Provided are a first container for collecting a first weight
20 of product dispensed by the first metering device during the
first calibration procedure and a second container for
collecting a second weight of product dispensed by the second
metering device during the second calibration procedure.
2s A first counter is operative to determine a first number of
revolutions turned by the first metering device during the
first calibration procedure and a second counter is operative
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s to determine a second number of revolutions turned by the
second metering device during the second calibration
procedure. A microprocessor is operatively connected to the
first and second counters.
io An input device is provided for entering the first and second
weights into the micro-processor and the micro-processor is
operative to determine a first dispensing rate, being a weight
of product dispensed per revolution, for the first metering
device, and a second dispensing rate for the second metering
is device .
The air-seeder cart could further comprise a distance sensor
operative to sense a distance traveled by the air-seeder cart,
the distance sensor operatively connected to the
2o microprocessor, and the microprocessor further operative to
determine a first application rate, being a weight of product
dispensed per unit of area covered by the air-seeder, for the
first metering device, and a second application rate for the
second metering device, and the microprocessor further
2s operative to display the first and second application rates to
an operator.
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DESCRIPTION OF THE DRAWINGS:
While the invention is claimed in the concluding portions
hereof, preferred embodiments are provided in the accompanying
is detailed description which may be best understood in
conjunction with the accompanying diagrams where like parts in
each of the several diagrams are labeled with like numbers,
and where:
i5 Fig. 1 is a side view of a tractor and air-seeder with a
calibration system of the invention;
Fig. 1A is a detail view of the transmissions driving the
metering devices;
Fig. 2 is a side view of the calibration motor and one-
way clutch;
Fig. 2A is a schematic end view of a one-way clutch;
Fig. 3 is a schematic side view of an alternate
embodiment using a separate calibration motor for each
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metering device;
Fig. 4 is a side view of a metering device rotation
counter;
to Fig. 5 is a side view of an alternate air-seeder cart of
the invention having three tanks and metering devices.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS:
Fig. 1 illustrates a system for performing a calibration
procedure simultaneously on at least first and second rotating
metering devices 1, 2 mounted on an air-seeder cart 3. The
metering devices 1, 2 are conventional. The air seeder cart 3
2o comprises a ground drive for rotating the metering devices 1,
2 in proportion to a speed of travel of the air-seeder cart 3
along the ground. The ground drive is conventional and
comprises a wheel sprocket on cart wheel 5 which drives
primary chain 6 which in turn rotates the metering devices 1,
2. The wheel sprocket can be disengaged from the cart wheel S
by an electric clutch or the like so that the cart 3 may
travel without rotating the metering devices 1, 2. The
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s electric clutch and wheel sprocket are located behind the cart
wheel 5 and are not illustrated.
Also conventionally, each metering device 1, 2 is operatively
connected to a separate tank T1, T2 for dispensing product
io from the tank. Each metering device 1, 2 dispenses a
substantially constant amount of product for each revolution
thereof.
The calibration system comprises a calibration motor 7
is operative to rotationally drive the first and second metering
devices 1, 2 simultaneously such that product is dispensed
from each metering device 1, 2 while the air-seeder cart 3 is
stationary. The calibration motor 7 drives the metering
devices 1, 2 through a one-way clutch 8 mounted on the
2o calibration motor 7 and attached to a double sprocket 9 as
illustrated in Fig. 2. The double sprocket 9 drives a
secondary chain 10 driving the metering devices 1, 2, and is
driven by the primary chain 6 from the cart wheel 5.
z5 When the electric clutch is engaged, the cart wheel 5 is
driving the primary chain 6 and rotating the double sprocket
9, the secondary chain 10 and the first and second metering
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s devices 1, 2, and the one way clutch 8 is not engaged. The
double sprocket 9 rotates freely, and the calibration motor 7
is not rotating. When the cart wheel 5 is disengaged from the
first and second metering devices, the calibration motor 7 can
be started and operates to engage the one-way clutch 8 to
io rotate the sprocket 9 and drive the chain 6 in the same
direction as it is driven by the cart wheel 5 to drive the
first and second metering devices.
Fig. 2A schematically illustrates one possible operation of
is the one-way clutch 8. When the cart wheel 3 is driving the
primary chain 6 in direction F, the inner surface 12 of the
one-way clutch 8 rotates in direction R and passes freely over
the dogs 11 mounted on shaft 13. However when the calibration
motor 7 is started, shaft 13 rotates in direction R, and the
2o dogs 11 bear against the inner surface 12 and cause the one-
way clutch 8 to engage and rotate the double sprocket 9,
driving the metering devices 1, 2 via secondary chain 10, and
also driving the primary chain 6 which rotates the wheel
sprocket freely when the electric clutch is disengaged. One-
2s way clutches are well known in the art and it is contemplated
that many conventional one-way clutches would be suitable for
the purpose.
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Alternatively a calibration motor may be provided to drive
each metering device 1, 2 individually as illustrated in Fig.
3. Electric clutches or one-way clutches can be used to allow
the ground drive to rotate the metering devices 1, 2 without
to rotating the calibration motors 7.
The illustrated calibration motor 7 is a hydraulic drive motor
however an electric or other suitable motor could be used as
well.
To illustrate the operation of the illustrated embodiment,
consider that the proportion between the rotation of the first
metering device 1 and the speed of travel of the air-seeder
cart 3 is a first ratio and the proportion between the
2o rotation of the second metering device 2 and the speed of
travel of the air-seeder cart 3 along the ground is a second
ratio. As the first and second ratio change, the application
rate for the first and second metering devices 1, 2 changes.
In the illustrated embodiment, these first and second ratios
are remotely individually adjustable by an operator from a
towing vehicle, the tractor 28, when the air-seeder cart 3 is
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s traveling along the ground, in a ratio range from zero,
wherein the metering device dispenses no product, to a maximum
ratio, wherein the metering device dispenses a maximum
application rate. Ratio indicators 14 on each of the first
and second transmissions 15, 16 allow an operator to view the
io point in the ratio range where each metering device 1, 2 is
operating.
The first and second ratios are adjusted by first and second
transmissions 15, 16 operatively connected to the ground drive
i5 by secondary chain 10 driving input shafts 17 and to the first
and second metering devices l, 2 by output shafts (not
illustrated). Electric actuators 15A, 16A act as first and
second ratio controls on the transmissions 15, 16. First and
second switches 15S and 165, mounted on the air-seeder cart 3,
2o activate first and second electric actuators 15A, 16A and
thereby adjust the first and second ratios. The actuators 15A,
16A are operable remotely from the tractor 28 as well as by an
operator standing adjacent to the air-seeder cart 3 at the
switches 15S, 16S. Seeder monitor 27, located in the cab of
25 the tractor 28, contains a microprocessor. Cab switch box 19
contains further switches to operate the actuators 15A, 16A,
as well as a lock-out operable to prevent operation of the
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s switches 155, 16S by the operator standing adjacent to the
air-seeder cart. The possibility of tampering or accidental
change to the ratio can thus be reduced.
Starting rotation of a metering device 1 or 2 using the
to calibration motor 7 initiates a calibration procedure for that
metering device. For best results, the first and second ratios
are adjusted to a mid-point of the ratio range during
calibration. Generally both will be started together so that
the calibration of both metering devices 1, 2 will proceed
is simultaneously. Starting the calibration motor 7, by opening
valve 18, starts both metering devices 1, 2 rotating and
initiates a first and a second calibration procedure.
The first switch 15S acts as a first control operative to stop
2o rotation of the first metering device 1 by reducing the first
ratio to zero, and thereby stops dispensing product from the
first metering device 1, thereby terminating the first
calibration procedure for the first metering device 1. This
operation of first switch 15S does not affect the rotation of
2s the second metering device 2, and it is allowed to continue
rotating.
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The second switch 16S can act as a second control operative to
stop rotation of the second metering device 2 by reducing the
second ratio to zero, and thereby stop dispensing product from
the second metering device 2, thereby terminating the second
calibration procedure for the second metering device 2.
to Alternatively, where there are only two metering devices, the
valve 18 may be operated to stop the calibration motor 7, and
thereby stop the second metering device 2. Where there are
three or more metering devices, the second switch 16S can be
used to allow a third calibration procedure to proceed. In
i5 this same manner any number of metering devices may be
calibrated simultaneously.
A first container 20 is located, as in the prior art, below
the first metering device 1 for collecting a first weight of
2o product dispensed by the first metering device 1 during the
first calibration procedure. A second container 21 is
similarly located below the second metering device 2 for
collecting a second weight of product dispensed by the second
metering device 2 during the second calibration procedure.
A sensor 22, as illustrated in Fig. 4, is mounted adjacent a
sprocket 23 on a shaft 24 of each metering device 1, 2 and
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s sends a pulse to the microprocessor in the seeder monitor 27
each time a sprocket tooth passes. The microprocessor then
determines a first number of revolutions turned by the first
metering device during the first calibration procedure, and a
second number of revolutions turned by the second metering
to device during the second calibration procedure.
An input device, here illustrated as monitor keypad 25 on the
seeder monitor 27, allows for entering the first and second
weights into the microprocessor. The microprocessor is
is operative to determine a first dispensing rate, being a weight
of product dispensed per revolution, for said first metering
device, and a second dispensing rate for said second metering
device.
ao A remote input device could comprise a keypad as well, but
could also comprise a scale 26, here shown as mounted on the
air-seeder cart 3, operable to determine the first and second
weights, and to send same directly to the microprocessor. A
bag containing the sample is hung from the scale 26, and the
2s scale 26 sends a signal indicating the weight to the
microprocessor.
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Once the dispensing rate of weight per revolution is known for
a particular product in a metering device, then it is only
required to connect a distance sensor, many of which are well
known in the art, operative to sense the distance traveled by
the air-seeder cart, to the microprocessor in order for the
to microprocessor to determine a first application rate, being
weight of product dispensed per unit of area covered by the
air-seeder, for the first metering device, and a second
application rate for the second metering device, and display
the application rates to an operator.
The microprocessor counts the revolutions of each metering
device 1, 2 and correlates these with the distance traveled,
and thus the area covered, while the metering devices were
rotating.
The system allows an operator to quickly, and with minimal
effort, accurately calibrate two, three or more metering
devices. The operator can stand beside the air-seeder cart,
and watch each container, turning off the metering devices as
the product in the corresponding catching containers becomes
sufficiently large to reduce scale errors to an acceptable
level.
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The advent of air-seeder carts with three, four or more tanks
with individual metering devices has greatly increased the
flexibility a farmer has to apply products at different rates.
The calibration system of the present invention allows three,
io four or more metering devices to be calibrated simultaneously,
at any rate for any metering device.
A system of the invention is illustrated in Fig 5 including
three metering devices M1, M2, and M3, three meter controls
i5 MC1, MC 2, and MC3, and three containers C1, C2, and C3.
For example where M1 is to dispense 200 pounds/acre of
nitrogen fertilizer, M2 is to dispense 5 pounds/acre of canola
seed, and M3 is to dispense 60 pounds/acre of phosphorous
2o fertilizer, the calibration procedure for all will be
initiated by starting the calibration motor 7 to begin
rotating all metering devices. The container C1 collecting
nitrogen fertilizer dispensed from M1 will be the first to
contain an adequate sample, after a simulated coverage of 0.1
25 - 0.2 acres, and so the control MC1 for M1 will be used to
disengage the metering device M1, allowing M2 and M3 to
continue rotating and dispensing product. The container C3
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s collecting phosphorous fertilizer dispensed from M3 will be
the next to contain an adequate sample, after a simulated
coverage of 0.4 - 0.5 acres, and so the control MC3 for M3
will be used to disengage the metering device M3, allowing M2
to continue rotating and dispensing product. Finally, the
io container M2 collecting canola dispensed from M2 will be the
last to contain an adequate sample, after a simulated coverage
of 4 - 5 acres, and so the control MC3 for M3 will be used to
disengage the metering device M3, or alternatively, since M3
is the last metering device operating, valve 18 may be used to
is simply stop the calibration motor 7.
Similarly four or more metering devices could be calibrated in
the same manner, and in any order, allowing the farmer to
fully utilize the flexibility of the multi-tank air-seeder
2o cart .
Where a remotely variable application rate is available, as in
the system described in detail above, the system also allows
accurate calculation and display of application rates over a
2s broad range.
Where remotely variable rates are not available, the
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s calibration will be accurate when rates are adjusted manually
over the operating range.
The foregoing is considered as illustrative only of the
principles of the invention. Further, since numerous changes
to and modifications will readily occur to those skilled in the
art, it is not desired to limit the invention to the exact
construction and operation shown and described, and
accordingly, all such suitable changes or modifications in
structure or operation which may be resorted to are intended
15 to fall within the scope of the claimed invention.
