Note: Descriptions are shown in the official language in which they were submitted.
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CONTROLLED DOWNWARD FORCE ON FURROW PACKING ELEMENT
This invention is in the field of seeding implements used in agriculture, and
in particular
implements that utilize a packing element, most commonly a packer wheel, as a
terraia
following gauge wheel to control the operating depth of the furrow openers as
well as
pack the furrow.
BACKGROUND
Trailing arm terrain following fiuTow opener assemblies are well known in the
agricultural implement industry. A typical example of such an assembly will
have an arm
pivotally attached at a front end thereof to the implement frame, and a packer
wheel
rotatably attached to the rear end of the artn. One or more furrow opener
brackets extend
downward from middle portions of the arm, and furrow openers are attached to
the
bottom of the brackets. The packer wheel is typically aligned with a furrow
opener to
paclc the furrow. A bias element, such as a spring, hydraulie cylinder, or
pneumatie
cylinder, exerts a downward force between the frame and the arm. The downward
force
forcies the furrow openers into the ground, and also forces the packer wheel
against the
ground.
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As the implement moves along the ground in rolling terrain, the arm moves up
and down
with respect to the frame as the relative positions of the packer wheel and
frame changes.
The packer wheel thus functions as a packing element by firming up the
loosened soil
araund and above the seed, and also acts as a depth gauge for the furrow
openers
mounted on the arm.
It is desirable to have a uniform and adequate packing force to achieve good
seed to soil
contact for germination. The advent of direct seeding or zero-till often
includes the
practice of shallow seeding and early seeding. With shallow seeding the
importance of
sut]Fi.cient packing is more critical since there is a higher potential of the
soil around the
see3 drying out if it is not firm. Conversely over-packing can make it
difficult for the
seeilling to emerge. While skid plates and track devices may also be used as
the packing
elernent, the wheel is most common, particularly with trailing arm furrow
opener
assemblies.
The downward bias force can usually be adjusted by mechanical, electrical or
electronic
means to change the force for different soil types and crop requirements. Some
soils are
harder and require considerably more force to push the furrow openers into the
ground
and keep them their, as well as exert sufficient force on the packer wheel to
pack the soil
over the furrow. Other soils are quite soft and require a much reduced bias
force to
maintain the furrow openers in the soil and pack the furrow.
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W.here the bias force is provided by hydraulic or pneumatic cylinders,
changing the
supply pressure to the cylinder changes the force. Where the bias force is
provided by a
spring, increasing or decreasing the spring compression level, changes the
force. Some
planters include in-cab adjustment capabilities so that the operator can
change the bias
force from the cab to compensate for soil types, moisture conditions, ground
speed, and
residue effects.
Examples of such a ftirrow opener assembly are found in United States Patent
Numbers
5,331,907 and 5,396,851 to 13eaujot. The Beaujot assemblies include separate
seed and
fertilizer openers mounted on an arm that includes a packingldepth-gauging
wheel at the
trailing end. A hydraulic cylinder that has an active oil supply is included
on each
opener. The operator can set the active oil pressure manually on the pressure-
controlling
valve or remotely thru an in-cab control to adjust the downward bias force.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a traiWig arm furrow
opener assembly
that overcomes problems in the prior art.
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Trailing arm furrow openers that utilize the packer wheel as the openers depth
gauge are
built such that the furrow openers attached to the arm are vertically
controlled by the
packer wheel. Because of the interconnected construction the drag and
penetrating forces
on the ground engaging furrow opener elements directly affect the resulting
vertical
packing force on the packing element.
On such a furrow opener assembly the drag forces resulting from pulling the
furrow
opener through the soil, and the upward forces on the fiurow opener resulting
from the
force required to maintain the furrow opener engaged in the ground combine to
exert an
upward force on the trailing arm. The rolling resistance force reqLured to
roll the packer
wheel forward along the ground also exerts an upward force on the arm. These
upward
forces reduce the amount of the downward bias force that is available to force
the packer
wheel, toward the ground and provide packing force.
Soil conditions can vary considerably from field to field and also within a
single field and
so the packing force varies considerably with the result that in some areas of
the field the
furrows are over-packed while in other areas the furrows are not sufficiently
packed. An
operator is un-aware of the packing, performance a.s it varies over different
portions of the
field or from field to field. The furrow opener apparatus of the present
invention
det.emiines the packing force exerted on the furrow and allows the operator to
adjust the
bias force exerted on the packer wheel to maintain the packing force within a
desired
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range as soil conditions vary.
In a first embodiment the present invention provides a furrow opener apparatus
comprising a furrow opener and a packer wheel oriented to roll along a furrow
made by
the furrow opener. A bias element is operative to exert a downward bias force
on the
packer wheel, and a sensing mechanism is operative to deternune a downward
packing
force exerted on the furrow by the packer wheel. A control mechanism is
operative to
allow the operator to adjust the downward bias force to maintain the packing
force within
a desired range.
In a second embodiment the present invention provides furrow opener apparatus
adapt.ed
for attachment to an agricultural seeding implement frame. The apparatus
comprises a
trailing arm adapted at a front end thereof for attachment to the frame about
a
substantially horizotital arm pivot axis oriented substantially perpendicular
to an
operating travel direction of the implement. A bias element is operative to
exert a
downward bias force on the arm. A fz-rrow opener bracket extends downward from
a
middle portion of the arm, and a furrow opener is attached to a lower end of
the furrow
opener bracket. A packer wheel is configured to support a rear portion of the
arm and
oriente.d to roll along a furrow made by the furrow opener, A sensing
mechanism is
operative to determine a downward packing force exerted on the furrow by the
packer
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wheel, and a control mechanism is operative to allow the operator to adja4t
the downward
bias force to maintain the packing force within a desired range.
nESCRIPTIqN 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
conjtmction with the aecompanying diagrams where like parts in each of the
several
diagrams are labeled with like numbers, and where:
Fig. I is a schematic side view of an embodiment of the furrow opener
apparatus of the
present invention;
Fig. 2 is a schematic side view of an alternate embodiment of the fttrrow
opener
] 5 apparatus of the present invention;
Fig. 3 is a schematic side view of a further embodiment of the furrow opener
apparatus
of the present invention;
Fig. 4 is a schematic top view of the attachment of the packer wheel to the
trailing arm
in the embodiment of Fig. 3.
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DETAILED DESCR[PTION OF THE ILLUSTRATED EMBODIMENTS
Fig.l illustrate.s a schematic side view of an embodiment of a furrow opener
apparatus 1
of the present invetttion. The furrow opener apparatus 1 comprises a furrow
opener 3 and
a packer wheel 5 oriented to roll along a furrow made by the furrow opener 3.
In the
illustrated embodiment the furrow opener apparatus 1 includes a trailing arm 7
adapted at
a front end thereof for attachment to an implement frame 9 about a
substantially
horizontal ann pivot axis APA oriented substantially perpendicular to an
operating travel
direction T of the impiement. The packer wheel 5 is configured to snpport a
rear portion
of the trailing arm 7 by attachment to a rear portion of the trailing aim 7
through a wheel
bracket 11. The furrow opener 3 is attached by a furrow opener bracket 13 to a
middle
portion of the trailing arm 7 forward of the packer wheel 5.
A bias element, illustrated as a hydraulic cylinder 15 connected to an active
hydraulic
source, is operative to exert a downward bias force F5 on the trailing arm 7.
The active
hydratilic source exerts a controllable pressure in the hydraulic cylinder 15,
and the
hydraulic cylinder 15 can extend and retract while exerting the bias force BF,
which bias
force BF can be varied by varying the pressure of the fluid in the hydraulic
cylinder. A
sensitig ntechanism 20 is operative to determine a downward packing force,
equal to the
illustrated upward packing force F4, exerted on the furrow by the packer wheel
5.
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In the embodiment of Fig. 1 the sensing mechanism 20 comprises the wheel
bracket l 1
pivotally attached at a front end thereof to a rear portion of the trailing
arm 7, with the
packer wheel 5 in turn rotatably attached to the rear end of the wheel bracket
11. The
sensing mechanism 20 also comprises a sensor link 21 connecting the trailing
arm 7 and
the wheel bracket 11 such that the position of the wheel bracket 11 with
respect to the
trailing arm 7 is substantially fixed. The packer wheel 5 on the wheel bracket
11 would
be free to move up and down with respect to the arm 7, except that the sensor
link locks
the two together. The sensor link 21 includes a sensor 23 operative to
determine the
sensed force SF exerted on the wheel bracket 11 by the bias element 13 through
the
trailing arm 7, from which the packing force F4 can be determined. A nmeasure
of the
packing force is indicated to an operator on a display 25.
The hydraulic cylinder 15 thus applies a force F5 on to the trailing arm 7.
The force F5 is
set by the operator by adjusting the pressure in hydraulic cylinder 15. The
cylinder 15
creates a downward moment around the arm pivot axis APA 9 equal to F5 times
the
perpendicular distance D5 between the cylinder center and pivot axis APA.
During
operation opposite upward moments are created as result of engaging the furrow
opener 3
in the soil. For example the rearward force Fl is a result of the soil
resisting travel of the
furrow opener 3 through the soil. Upward force F2 is a result of the soil
resisting
dowriward penetration of the furrow opener 3 into the soil. Rearward force F3
is a result
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of rolling resistance of the soil to the rotation of the packer wheel 5. The
difference
between the upward moments (FIDI + F2D2 + F3D3) and the downward moment
(F5D5) provided by the hydraulic cylinder 15 is what is left to provide the
packing force
F4, which creates a moment F4D4.
Since all distances are substantially fixed, and Fl, F2, and F3 vary with soil
conditions, in
order to maintain a uniform resultant vertical paclcing force F4, the pressure
in hydraulic
cylinder 15 must be varied so that F5 compensates for the varying soil forces
to provide a
packing force F4 that is within acceptable limits.
The actual packing force may not need to be determined in practice, where an
operator
will note the sensed force F and inspect the field behind the implement to
judge if
packing is satisfac-tory. The operator will then know which range of values of
SF will
provide a satisfactory packing force, and can maintain the pressure in the
hydraulic
cylinder 15 accordingly.
Fig. 2 illustrates an alternate furrow opener apparatus 101 where the sensing
mechanism
120 is provided by a strain gauge type sensor 123 which measures the bending
forces on
the trailing arm 107 caused by the bias force BF exerted by the hydraulic
cylinder 115
forcinc, the packer wheel 105 against the ground, and thus allows
determination of the
packing force F4.
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It is crnitemplated that the sensing mcchanism could be configured to more
indirectly
determine the downward packing force F4 exerted on the furrow by the packer
wheel 5
by measuring the foroes Fl and F2 exerted on the furrow opener 103 by the
soil. Thus
instead of orienting the sensing mechanism to measure the bending forces in
the trailing
arm 107, the sensor conld be configured as illustrated by sensor 123A to
measure the
bending forces on the furrow opener bracket 113. The forces Fl and F2 on the
furrow
opener 103 vary with soil conditions, causing the packing force F4 to vary. It
is
contemplated that by measurirtg the changing bending forces on the furrow
opener
bracket 113, and ignoring the rolling resistance F3 which is not expected to
vary
significantly compared to the variance in the soil forces Fl, F2 on the furrow
opener 103,
an approximation of the packing force can be derived that will be satisfactory
for the
purposes of the apparatus 101.
Fig. 3 illustrates a further alternative fuFrow opener apparatus 201 with two
furrow
openeis, a fertilizer furrow opener 203A and a seed furrow opener 203B
mrninted on the
bottom of corresponding furrow opener brackets 213A, 213B. There thus are
three
ground contacting elements the fertilizer furrow opener 203A, the seed furrow
opener
203F1, and the packer wheel 205. The ground contacting elements are mounted on
the
rear portion end of the trailing ann 207. The trailing arm 207 is pivotally
mounted to a
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hanging bracket 208 at arm pivot axis APA. The hanging bracket 208 also
includes pivot
mount for pivotally mounting active hydraulic cylinder 215.
Hydiaulic hose 212 is used as an oil return in the field working position and
as the oil
supply line when lifting the apparatus 201 off the ground. Hydraulic hose 214
supplies
the active oil from the pressure-control valve 231 to cylinder 215. Valve 231
is pressure
adjusted via contro1233. Hydraulic hose 216 supplies pressurized tractor
hydraulic oil to
valve 231. It is noted that, in contrast to the embodiments of Figs. 1 and 2,
in the
embodiment of Fig. 3 the hydraulic cylinder is located under the trailing arm
207 and
thus excrts a bias force BF in the retracted direction rather than the
extended direction to
exert the required downward bias force BF on the trailing arm 207.
The undisturbed ground surface is indicated at 241, the soil surface loosened
by the
furrow openers is indicated at 243, and the final packed soil surface is
indicated at 245.
The soil exerts drag soil reaction forces Ft and F2 and vertical soil
penetrating reaction
forces F3 and F4 on the furrow openers 203A, 203B, and exerts a rolling
resi.stance soil
reaction force F5 on the packer wheel 205. These forces as described above
with re.spect
to the embodiment of Fig. I combine to create an arm lifting moment around the
arni
pivot axis APA.
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The active hydraulic cylinder 215 applies a bias force F7 on to the trailing
arm 207. The
force F7 is set by the operator by adjusting the pressure in valve 231. The
cylinder 215
creates an arm lowering moment around the arm pivot axis APA. F6 is the
resultant soil
vertical packing force acting on the packer wheel 205. The resulting force is
equal to the
opener lowering moments minus the opener lifting moments divided by the
corresponding distances as described above. Again, since all distances are
substantially
fixed and Fl, F2, F3, F4, and F5 vary with soil conditions, in order to
maintain a uniform
resultant vertical packing force F6, the cylinder pressure mu.st be varied so
that F7
compensates for the varying soil forces.
To provide the sensing mechanism 220 in the embodiment of Fig. 3, the packer
wheel
205 is mounted to a wheel plate 251 that is pivotally attached to a rear
portion of the
trailing arm 207. A top view of the wheel plate 251 is shown in Fig. 4 and
shows that
there are two wheel plates 251 with the rear end of the trailing arm 207
between them.
The plates 251 are attached together and pivot up and down on pivot pin 253
extending
through the plates 251 and the rear end of the tailing arm 207. The axle 255
of the packer
wheel 205 is attached to the inner one of the wheel plates 251. As illustrated
in Fig. 3, a
sensor mount 257 is rigidly attached to the trailing arm 207 by bolts or pins
through holes
259 which allow for adjustment of the vertical location of the packer wheel
205 with
respect to the furrow openers 3A, 3B to adjust the depth of the furrows.
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A sensor link 221 connects the sensor mount 257 and the wheel plates 251 such
that the
position of the wheel plates 251 with respect to the sensor mount 257 is
substantially
fixed. The sensor link 221 includes a load sensor 223 operative to determine a
force
exerted on the plate 251 by the sensor mount 257 as a result of the bias force
F7 exerted
on the trailing arm 207 by the hydraulic cylinder 215.
By allowing plate 251 to pivot freely about pivot pin 253 and mounting the
load sensor
223 between plates 251 and sensor mount 257, the load sensor 223 can
continually
determine the packing force F6. An indication of the sensed force is then sent
via cable
or hose 227 to a monitor 225 visible to the operator. The operator can
manually or
remotely adjust valve 231 until a satisfactory reading is achieved on the
monitor 225.
Alternately a change in the sensed force can directly adjust the valve 231 via
valve
control 233 if the control mechanism is set to respond to the load sensor
signal. Further
in the alternative the sensed load results can be processed by an electronic
processor 235
or the like, which in turn provides an adjustment signal to valve control 233
thus
providing an automatic control mechanism operative to adjust the downward bias
force
F7 to maintain the packing force F6 within a desired range. Further again the
processor
235 could calculate an average reading over a short time and adjust oontrol
233 based on
the average, thereby smoothing and damping the operation of the valve 231. A
manual
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over-ride can be provided to allow the operator to over-ride or turn off the
automatic
adjustment and adjtkst the downward bias force manually.
As illustrated in Fig. 3, the sensor mechanism 220 can be configured such that
the pivot
pin 253 about which the wheel plates 251 pivot is approximately the same
vertical
distance off the ground as the rotational axi4 259 of the packer wheel 205 so
that the
sensor 223 does not detect the rolling resistance force F5.
Thus the present invention provides a furrow opener apparatus that provides a
packing
force that can he maintained within a desired rwge, either by visual
monitoring and
manual adjustment by an operator, or by a system that automatically adjusts
the bias force
exeirted on the packer wheel. The illustrated embodiment show a bias element
provided
by a hydraulic cylinder, however it is contemplated that a compression spring
could
provide the required bias force if the compression of the spring, and thus the
bias force
exerted thereby, could be adjusted readily.
Trailing arm furrow opener assemblies are also known where the trailing arm
includes a
parallel link with upper and lower parallel arm members attached to a rear
link that is
maiutained in a substantially constant fore and aft angular orientation as it
moves up and
down. A sensing mechanism can be readily adapted to determine the packing
force in
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these parallel link trailing arm furrow opener assemblies and allow the
operator to
maintain the packing force in a desired range as soil forces vary.
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.
