Note: Descriptions are shown in the official language in which they were submitted.
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SEED METERING APPARATUS FOR A SEEDER
This invention is in the field of agricultural implements and in particular a
seed metering
apparatus for a seeder that provides improved placement of seeds such as
canola and
corn.
BACKGROUND
In the agricultural industry, considerable research has been done and is
ongoing to
determine optimum plant spacing for various crops to provide maximum yields.
This
desired spacing in turn gives a desired plant population of plants per unit of
area, such as
a square foot or acre. In order to translate this into a usable form for the
farmer, the
average number of seeds in a unit of weight, such as pounds, is determined for
an average
sample of representative seeds. The number of desired plants per acre is then
translated
into a seeding rate of pounds per acre.
Seed sizes and weights as well as desired plant populations vary dramatically
between
different crops. A typical corn variety has large sized seeds and may have
about 1200
seeds per pound, while a typical wheat variety has smaller medium sized seeds
and may
have about 12,000 seeds per pound, and a typical canola has very much smaller
sized
seeds and may have about 120,000 seeds per pound.
Similarly desired plant populations also vary dramatically. A typical
population for corn
may be about 0.5 plants per square foot (22,000 plants per acre), for canola
about 5 plants
per square foot (220,000 plants per acre), and for wheat about 25 plants per
square foot
(1,100,000 plants per acre). Canola seed can cost up to $10 per pound, and so
current
research is showing that the traditional plant population of 10 plants per
square foot can
be reduced to 5 per square foot if fairly evenly distributed.
Ideally these plants are spaced equally in all directions in a grid like
arrangement
however in practice a given seeder has a fixed spacing between the furrow
openers and so
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the spacing between the rows of plants is fixed for any particular seeder,
typically for a
modem minimum tillage air seeder these row spacings are 10-12 inches. With the
spacing between rows fixed, altering the seeding rate alters the spacing
between seeds in
a row.
With a wheat crop on a 12 inch row spacing, there should be about 25 seeds per
foot of
row, and the distance between seeds is then less than %i inch, With canola
there should
be about 5 seeds per foot of row, and the distance between seeds is 21/Z
inches.
With corn there should be about 0.5 seeds per foot of row, and the distance
between. seeds
24 inches. For maximum yields however, corn is seeded at a wider row spacing,
typically 30 inches or more, with a row type planter. Corn is sometimes seeded
with a 12
inch spacing air seeder by only using every other furrow opener so the row
spacing is 24
inches and there are thus about 1.0 seeds per foot of row.
Thus it can be seen that to get an even plant spacing, the spacing is much
more critical for
corn than for either wheat or canola, while the spacing of canola seeds is
more critical
than for wheat. To achieve the desired even spacing, singulating metering
devices are
commonly used for planting corn. These typically comprise pockets or recesses
on a
rotating disc and take the seeds from a seed tank one at a time and drop them
into a
furrow.
In contrast, seed metering devices for seeding wheat and canola typically work
on more
of a bulk principal. One typical type of seed metering device includes a
rotating feed
roller with recesses that can be in the form of grooves extending
longitudinally along the
length of the outer surface of roller parallel to the axis of rotation, or in
the form of
notches or pockets or the like spaced evenly along the outer surface of the
roller. The
feed roller is typically mounted below the feed opening at the bottom of a
seed tank and
configured such that the intake side of the roller is inside the feed opening
exposed to the
seeds in the tank and the outer output side is above the furrow in a
conventional seeder,
or in an air seeder is above the air stream that carries the seeds to the
furrow openers to
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be deposited in the ground. As the roller rotates, seeds fill the recesses and
are carried
from the seed tank and dropped into the furrow in a conventional seeder, or
are fed into
the air stream of an air seeder.
The number of seeds dispensed is proportional to the rotational speed of the
feed roller or
auger, and the rate of metering seeds is adjusted by varying the rotational
speed. The
rotational speed is also coordinated with ground speed so that the same amount
of seed is
dispensed for each foot of distance travelled.
As a feed roller rotates, the seed is dispensed essentially in pulses. The
recesses spill
their contents into the furrow or air stream as they rotate, with one emptying
before the
next starts to spill. With wheat this is not particularly problematic, as the
seed spacing is
not so critical, and in addition the volumes of seed required to be dispensed
for a typical
seeding rate require a rotational speed that is relatively high so that the
pulses blend
together and the result is a fairly constant flow of wheat seeds that is
satisfactory for
seeding wheat.
With canola however, the number of seeds that are contained in any particular
recess is
about 10 times the number of wheat seeds that are contained in the same groove
or
recess. In addition it is desired only to have 5 canola seeds per foot instead
of 25 wheat
seeds, so a feed roller rotating at a speed suitable to dispense the desired
rate of wheat
seeds will dispense canola seeds at about 50 times the desired rate.
For seeding canola then, the speed of rotation must be reduced to 1/50 the
rotational
speed for wheat, however reducing the speed that much becomes problematic as
the
pulsing nature of the flow of canola seeds is accentuated. The flow of canola
seeds into
the air stream is very uneven, and although the correct number of seeds per
foot of row
will be dispensed, the seeds will be deposited in the furrow in clumps instead
of evenly
spaced. In order to address this problem, different feed rollers are often
used for wheat
and canola. The canola feed rollers will have shallower and smaller recesses
such that
less seed is dispensed with each revolution, and the rotational speed can be
increased and
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the pulsing effect reduced. The rotational speed of these canola feed rollers
however is
still very slow, in the order of I revolution per minute. At these slow
speeds, and given
the nature of a canola seed being very small and round, the movement and
vibration
caused by the seeder travelling along a field causes the canola seed to shake
out of the
recesses, accentuating the uneven flow.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a seed metering apparatus
for an air
seeder that overcomes problems in the prior art.
In prior art feed rollers, the recesses that actually take the seeds from the
tank and move
them to the air stream are spread along the whole outer surface of the roller
from one end
to the other. In a typical configuration, the roller will be some inches long
and exposed
to the seeds in the tank on an intake side and open to the air stream on the
output side
such that as the roller rotates seeds drop from the recesses into the air
stream. In some
types of air seeder distribution networks, chutes are provided at the output
side to receive
the seeds being dispensed and direct same into separate air streams.
Where each air stream is feeding the same number of furrow openers, these
chutes will be
of equal width so that each air stream receives the same amount of seed. It is
also known,
where the air streams are feeding different numbers of furrow openers, to vary
the chute
widths so that the width of the roller feeding each chute is proportional to
the number of
furrow openers being fed, and so each furrow opener receives the same amount
of seed.
In a first embodiment the present invention provides a seed metering apparatus
for a
seeder. The apparatus comprises a seed container with a feed opening in a
bottom
thereof. A feed shaft is rotatably mounted in a substantially horizontal
orientation
extending substantially from a right side of the feed opening to a left side
thereof. At
least one feed disc is mounted to the feed shaft such that the at least one
feed disc and
feed shaft rotate together, and a plurality of disc recesses are substantially
equally spaced
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along a periphery of the at least one feed disc. A shield plate extends from
the right side
of the feed opening to the left side thereof in an upright orientation from a
bottom edge
thereof to a top edge thereof, the shield plate substantially parallel to and
adjacent to a
front side of the feed shaft. The shield plate defines a disc slot having a
width
corresponding to a thickness of the at least one feed disc and configured such
that the at
least one feed disc can extend through the disc slot with seeds substantially
prevented
from passing between edges of the disc slot and the at least one feed disc.
The feed shaft,
at least one feed disc, and shield plate are configured such that the shield
plate
substantially seals the feed opening, and such that an intake portion of the
periphery of
the at least one feed disc is located in the feed opening exposed to seeds in
the seed
container, and such that an output portion of the at least one feed disc
extends forward of
a front face of the shield plate through the disc slot. Rotation of the feed
shaft carries
seeds out of the seed container in the disc recesses such that the seeds drop
into a seed
receiver below the front face of the shield plate.
In a second embodiment the present invention provides a seed metering
apparatus for an
air seeder. The apparatus comprises a seed container with a feed opening in a
bottom
thereof. A feed shaft is rotatably mounted in a substantially horizontal
orientation
extending substantially from a right side of the feed opening to a left side
thereof A.
plurality of feed discs are mounted to the feed shaft such that the feed discs
and feed shaft
rotate together, and a plurality of disc recesses are substantially equally
spaced along a
periphery of each feed disc. A shield plate extends from the right side of the
feed
opening to the left side thereof in an upright orientation from a bottom edge
thereof to a
top edge thereof. The shield plate is substantially parallel to and adjacent
to a front side
of the feed shaft. The shield plate defines a disc slot for each feed disc,
the disc slots
having a width corresponding to a thickness of the feed discs and configured
such that the
feed discs can extend through the corresponding disc slots with seeds
substantially
prevented from passing between edges of the disc slots and the feed discs. The
feed
shaft, feed discs, and shield plate are configured such that the shield plate
substantially
seals the feed opening, and such that an intake portion of the periphery of
each feed disc
is located in the feed opening exposed to seeds in the seed container, and
such that an
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output portion of each feed disc extends forward of a front face of the shield
plate
through the corresponding disc slots. Rotation of the feed shaft carries seeds
out of the
seed container in the disc recesses such that the seeds drop into a seed
receiver below the
front face of the shield plate.
Instead of gathering and dispensing seeds across the entire width of the seed
opening the
feed disc of the present invention gathers and dispenses seeds from only an
area equal to
the thickness of the disc. The disc therefore rotates much faster than a
conventional feed
roller, and thus the flow of seeds from the metering apparatus is much more
uniform, and
seed spacing in the furrow is thus more uniform. The higher speed also reduces
the
effects of field vibrations on the seed flow to a negligible amount.
Assemblies with different disc thicknesses and/or disc recess configurations
can be
interchangeable in the feed opening to provide metering for different sized
seeds and
different seeding rates. A roller assembly with a conventional feed roller can
also be
mounted in the feed opening if desired.
DESCRIPTION OF THE DRAWINGS
While the invention is claimed in the concluding portions hereof, preferred
embodiments
are provided in the accompanying 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:
Fig. 1 is a perspective view of an embodiment of a seed metering apparatus of
the
present invention, the apparatus having a single feed disc;
Fig. 2 is a front view of the embodiment of Fig. 1;
Fig. 3 is a schematic side view of the embodiment of Fig. 1;
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Fig. 4 is a front view of the feed disc in the embodiment of Fig. 1;
Fig. 5 is a perspective view of an embodiment of a seed metering apparatus of
the
present invention where the apparatus has a plurality of teed discs;
Fig. 6 is a perspective view of the disc assembly of the embodiment of Fig. 5;
Fig. 7 is a perspective view of the seed container of the embodiment of Fig.
5;
Fig. 8 is a perspective view of the embodiment of Fig. 5 with the disc
assembly of Fig.
6 removed and replaced with a conventional feed roller assembly, and with seed
receiver removed;
Fig. 9 is a perspective rear view of seed container and seed receiver of the
embodiment
of Fig. 5 with seed receiver removed;
Fig. 10 is a schematic front view of a feed disc and disc slot that are wider
than that
shown in the embodiment of Fig. 5;
Fig. 11 is a perspective view of a disc assembly with dividers between
adjacent disc
slots;
Fig. 12 is a schematic front detail view of the disc slot and feed disc of the
embodiment
of Fig. 5;
Fig. 13 is a schematic sectional side detail view of the disc slot and feed
disc of the
embodiment of Fig. 5.
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DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
Figs. 1 - 3 illustrate an embodiment of a seed metering apparatus t of the
present
invention for a seeder. The apparatus I comprises a seed container 3 with a
feed opening
in a bottom thereof. The illustrated seed container 3 is a hoppcred container
that is
configured to be attached on the bottom of a large tank such as is used to
carry
agricultural seeds on an air seeder.
A feed shaft 7 is rotatably mounted in bearings 9 in a substantially
horizontal orientation
and extends across the feed opening 5 from a right side to a left side
thereof: A feed disc
l l is mounted to the feed shaft 7 such that the feed disc 11 and feed shaft 7
rotate
together. The illustrated feed shaft 7 has a hexagonal cross section as does
the inner hole
of the feed disc 11 such that both turn together. Other shapes or a keyway or
the like
could also be used cause both to rotate together. A plurality of disc recesses
13 are
equally spaced along a periphery of the feed disc 11.
A shield plate 15 extends from the right side of the feed opening 5 to the
left side thereof
in a generally upright orientation from a bottom edge 15A thereof to a top
edge 15B
thereof. The shield plate 15 is parallel to and adjacent to a front side of
the feed shaft 7
and defines a disc slot 17 having a width W corresponding to a thickness T of
the feed
disc 11 such that the feed disc 11 can extend through the disc slot 17 with
seeds
substantially prevented from passing between edges of the disc slot 17 and the
feed disc
IL
The feed shaft 7, feed disc 11, and shield plate 15 are configured such that
the shield
plate 15 seals the feed opening 5, and such that an intake portion I I A of
the periphery of
the feed disc 11 is located in the feed opening 5 exposed to seeds 19 in the
seed container
3, and such that an output portion 11B of the feed disc 11 extends forward of
a front face
15F of the shield plate 15 through the disc slot 17.
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Thus in the apparatus 1, rotation of the feed shaft 7 in the direction R
carries seeds 19 out
of the seed container 5 in the disc recesses 13 such that the seeds 19 drop
into a seed
receiver 21 below the front face 15F of the shield plate 15. The seed receiver
21 directs
the seeds 19 eventually into one or more furrows made by furrow openers of the
seeder,
Where the seeder is an air seeder, the seed receiver 21 directs the seeds 19
into an air
stream for distribution to the furrow openers.
In the illustrated apparatus 1, the feed disc 11 includes an expanded circular
core portion
23 that is wider than the disc slot 17, with disc teeth 25 extending from the
circular core
portion 23 to form the disc recesses 13 and extending through the disc slot
17. The feed
disc 11 with circular core portion 23 and disc teeth 25 is illustrated in Fig.
4.
Right and left seed plates 27 extend rearward from a rear face 15B of the
shield plate 15
from corresponding right and left edges of the disc slot 17. The rear edges
27A of the
seed plates 27 have a circular shape corresponding to the circular core 23 and
in
proximity to the circular core 23. The seed plates 27 are in close proximity
to the sides of
the disc teeth 25 such that when the feed disc 11 rotates in direction R,
seeds 19 are
prevented from moving up between the teeth 25 and the side plates 27, thereby
reducing
seed damage.
In the illustrated apparatus 1, the seed plates 27 also extend forward from
the front face
15F of the shield plate 15 from corresponding right and left edges of the disc
slot 17 such
that the teeth 25 rotate between the seed plates 27, and seeds 19 carried out
of the seed
container 5 in the disc recesses 13 are guided to fall downward between the
seed plates
27.
Compared to a conventional feed roller with recesses on the entire outer
surface thereof
and extending across the entire width of the feed opening 5, the illustrated
feed disc 111
will turn at a much higher rotational speed to dispense the same rate of seeds
from the
seed container 3 as the conventional feed roller. Thus a much more uniform
flow of seed
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is received by the seed receiver 21 as pulsations in the flow are much reduced
because of
the increased rotational speed.
Figs. 5 - 9 illustrate an alternate embodiment of a seed metering apparatus
101 of the
present invention for use in an air seeder. The apparatus 101 comprises a seed
container
103 with a feed opening 105 in a bottom thereof. A feed shaft 107 is rotatably
mounted
in a substantially horizontal orientation extending substantially from a right
side of the
feed opening 105 to a left side thereof. A plurality of feed discs 111 are
mounted to the
feed shaft 107 such that the feed discs 111 and feed shaft 107 rotate
together. A plurality
of disc recesses 113 are equally spaced along a periphery of each feed disc
111.
A shield plate 115 extends from the right side of the feed opening 105 to the
left side
thereof in an upright orientation from a bottom edge 115A thereof to a top
edge 115B
thereof. The shield plate 115 is parallel to and adjacent to a front side of
the feed shaft
107. The shield plate 115 defines a disc slot 117 for each feed disc 111. The
disc slots
117 have a width W corresponding to a thickness T of the feed discs 111 and
are
configured such that the feed discs 111 can extend through the corresponding
disc slots
117 with seeds substantially prevented from passing between edges of the disc
slots 117
and the feed discs 111. Thus seeds 1 19 are prevented from leaking out of the
seed
container 103.
The feed shaft 107, feed discs 111, and shield plate 115 are configured such
that the
shield plate 115 substantially seals the feed opening 105, and such that an
intake portion
111 A of the periphery of each feed disc 111 is located in the feed opening
exposed to
seeds in the seed container 103, and such that an output portion 111B of each
feed disc
111 extends forward of a front face 115F of the shield plate 115 through the
corresponding disc slots 117. Rotation of the feed shaft 7 carries seeds 119
out of the
seed container 103 in the disc recesses 113 such that the seeds 119 drop into
a seed
receiver 121 below the front face 115F of the shield plate 115.
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In the illustrated apparatus 101, as shown in Fig. 6, the feed shaft 107 is
rotatably
mounted in bearings 109 in end plates 131 of the shield plate 115 such that
the feed shaft
107, feed discs 111, and shield plate 115 form a disc assembly 133 that is
removably
mounted in the feed opening 105. Clips 135 as shown in Fig. 7 can be released
to
remove the disc assembly 133. Thus the illustrated disc assembly 133 with feed
discs
111 having a thickness T and the illustrated configuration of disc recesses
113, can be
replaced by a second disc assembly with feed discs 111', as schematically
illustrated in
Fig. 10, having a greater thickness T' (or a lesser thickness if the situation
warrants) and a
different configuration of disc recesses 113', and of course a shield plate
115' configured
accordingly.
Thus a wide variety of crops can be seeded effectively. For example for
seeding small
seeds like canola, the thickness of the feed disc 111 will be small, and the
disc recesses
113 will likewise be quite small, while for seeding large seeds like corn, a
thicker feed
disc 111' can be provided with larger disc recesses 113' configured to be more
suitable
for the larger seeds. It is contemplated that it may be possible to size the
recesses 113' to
be about the same size as a corn seed, such that the corn seeds are carried
out of the seed
container 1 03 one at a time.
Further in the illustrated apparatus 101 a roller assembly 141, as illustrated
in Fig. 8, can
be provided to allow seeding still further different types of crops, such as
wheat. The
roller assembly 141 comprises a feed roller 143 with roller recesses 145
spaced evenly
along an outer surface thereof. A bearing 147 is mounted on each end of the
feed roller
141 and the roller assembly 141 is configured to removably mount in the feed
opening of
the seed container 103 secured by the clips 135 in place of the disc assembly
133. The
roller assembly 141 is configured such that when the feed roller 143 is
stopped, seeds are
prevented from moving out of the seed container 103, and such that when the
feed roller
143 rotates seeds are moved out of the seed container 103 in the roller
recesses 145.
In the illustrated apparatus 101 the seed receiver 121 comprises a chute 151
mounted
under each disc slot 117. Each chute 151 is operative to direct received seeds
119 into an
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air stream of an air seeder for delivery to at least one furrow opener. Figs.
8 and 9 show
the apparatus 101 with the seed receiver 121 removed. A primary air stream is
directed
into the input port 153 of the seed receiver 121, and is divided into a
plurality of separate
secondary air streams that exit the seed receiver 121 through output ports
155. The
chutes 151 direct the dispensed seeds into the secondary air streams through
venturis in
the seed receiver, and conduits attached to the output ports carry the
secondary air
streams AS' and entrained seeds to furrow openers.
Fig. 11 illustrates a disc assembly 233 that includes dividers 253 extending
forward from
the front face 215F of the shield plate 215 between adjacent slots 215. The
dividers 253
are configured to maintain a flow of seeds from one feed disc 211 into the
seed receiver
221 separate from the flow of seeds from a second adjacent feed disc 211. Some
seed
types may be prone to scattering when exiting the disc recesses and such a
divider 253
will ensured that the seeds drop into the proper location on the seed receiver
221.
The feed discs 111 can be configured, using a hex shaft such as illustrated in
the
apparatus 1 of Fig. I or using a keyed shaft as schematically illustrated in
Fig. 13, or like
means known in the art such that the feed discs 111 are slidable along the
feed shaft 107.
The feed discs I i 1 will be maintained in position on the feed shaft 107 by
their extension
through the disc slots 117. Such an arrangement facilitates assembly of the
disc assembly
133.
Detailed schematic front and side views of the feed disc 111 and slot 117 are
shown in
Figs. 12 and 13. It is contemplated that in a typical application the feed
shaft 107 and
discs Ill will be rotated in direction R such that rotation of the feed shaft
107 moves a
bottom edge of the feed discs I l 1 forward through the slot 117. In order to
reduce
jamming of seeds between the edges of the disc slot 117 and the periphery of
the feed
disc 111, a portion 117A of each disc slot 117 adjacent to a bottom edge of
each feed disc
111 is widened to reduce jamming of seeds between the edges of the disc slot
117 and the
periphery of the feed disc 111, and reduce seed damage.
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As described above the present invention provides a seed metering apparatus
for seeders
that reduces pulsations in the flow of seeds dispensed, and also reduces the
effects of
seeder movement vibration on the flow of seeds from the metering device,
thereby
providing a more uniform flow of metered seeds and improved uniformity of seed
placement in furrows.
The foregoing is considered as illustrative only of the principles of the
invention.
Further, since numerous changes 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 to fall within
the scope of
the claimed invention.
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