Note: Descriptions are shown in the official language in which they were submitted.
~ 9681
The present invention relates in general to the
control of agricultural equipment and more specifically to
the control of implements such as pneumatic seeders, fertilizer
applicators and/or chemical applicators.
BACK~7ROUND OF THE INVENTION
There are several types of agricultural machines
on the market which rely on machine-generated pneumatic pressure
for effective operation. One such machine is the so-called
"air seeder", a machine which meters and distributes, via a
stream of pressurized air, seeds to ground openers for the
purpose of planting the seeds. Such machines or others based
on similar principles of operation can be used for application
of fertilizers and chemicals to the ground. The application
of fertilizers and chemicals, if done by way of an air seeder,
can be accomplished simultaneously with the planting of the
seeds if desired.
On many existing air seeders problems can arise
should the air supplv system fail. Since such seeders normally
feed the seeds mechanically into the pneumatic delivery conduit
failure to stop such mechanical feed when the air supply stops
can result in a jammed or blocked delivery conduit, which is
often difficult and time consuming to unplug, and which in
turn can cause damage to the mechanical feed.
SU~RY OF THE INVENTION
The present invention overcomes these problems of
the prior art by interconnecting the control for the mechanical
feed mechanism and the air supply so that should the air supply
fail for any reason whatsoever the mechanical feed will stop
and no additional seeds will be fed into the delivery conduit.
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Should the air supply fail all the seeds in the delivery
conduit will stop their forward motion at the predetermined
spacing as controlled by the feed and, more importantly no
additional seeds will enter the delivery conduit, which seeds
would otherwise accumulate and pile up to block the conduit
in the absence of the pneumatic flow which would otherwise
carry the seeds along the conduit.
The control system of the present invention is
electrical in nature, is inexpensive to assemble and install
and is relatively simple to operate. A pneumatic control svstem
which achieves the same end is disclosed and claimed in
Canadian Application Serial Number 390,527 filed November 20,
1981 and assigned to the assignee of the present invention.
The electrical system of this invention is a viable alternative
to the pneumatic system of the aforementioned application and
may be used in situations where thè pneumatic system is, perhaps,
difficult to install.
The invention may be incorporated in new equipment
or it may be added with very little difficulty to existing seeder
equipment as an improvement thereto. The invention involves
the provision of a suitable pressure-sensitive pick-up, such
as a piezo-electric transducer, which is positioned within the
source of pressurized air and which provides an electrical
signal which is used to operate a control unit or actuator.
The control unit could be a solenoid which is mechanically
connected to a clutch unit which in turn is adapted to transmit
mechanical power to the feed unit. When the control unit is
actuated the clutch will operate so as to effect operation of
the feed unit but should there be a failure of the air supply
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.
the clutch unit will operate so as to disengage the drive
unit from the feed unit and thus stop the feed unit, thereby
preventing the entry of any additional seeds into the delivery
conduit.
Various controls or switches can be incorporated into
the electrical circuit so that control of various mechanisms
can be achieved or so that the operator can deliherately disengaa,e
the mechanical feed even though the pressure source is still
operative.
Broadly speaking therefore the present invention
provides in an agricultural implement for dispensing particulate
material and having: feed means for feeding predetermined
amounts of the material to a delivery conduit, drive means for
the feed means, a source of air under pressure, and air conduit
means connecting the source with the delivery c,onduit to aid
in the,passage of fed material along the delivery conduit, the
' improvement comprising:clutch me'ans loc'ated between the drive
- means and the feed means, electrically-controlable actuatormeans
operatively connected to the clutch means, pressure-sensitive
transducer means located a~. the source, and circuit means
connecting the transducer means with the actuator means,
whereby pressure-sustained electrical signals transmitted from
the transducer means to the actuator means penmits the actuator
means to maintain the clutch means in a position to connect
the drive means with the feed means, but a negative pressure
change at the source will cause the actuator means to operate
the clutch means to disconnect the drive means from the feed
means to thereby terminate the feeding of the material.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows schematically the principles of
operation of an air seeder without the present invention
incorporated therein.
Figure 2 shows a first embodiment of an electrical
control system according to the present invention.
Figure 3 shows a second embodiment of an electrical
control system according to the present invention.
Figure 4 shows a third embodiment of an electrical
control system according the the present invention.
DESCRIPTION OF THE PREFERRED Er~BODIMENT
Figure 1 is intended to illustrate, purely in a
general form, the environment in which the present invention
operates. It is understood that while particularly applicable
; to air seeders, of which there are many varieties, the invention
could be applicable to other analogous equipment.
Figure -1 first of all generally illustrates an air
seeder 22 which has a source of pressurized air which, for
the sake of simplicity, is illustrated as a centrifugal blower
10. Such a blower could be directly powered by the engine of
the tractor which carries or pulls the air seeder; it could
be powered by a "power take off" (PTO) mechanism; it could
have its own source of power such as a battery-operated electric
motor or an auxiliary fuel powered motor; or it could be ground
driven. The blower 10 is shown as having vanes 12 which are
attached to the shaft 14 and as the shaft rotates according to
the arrow A air is forced into the outlet 16 so as to create a
pressurized flow of air, which air is conducted via a suitable
line or tube 18 to the delivery conduit 20 of the seeder 22.
Seeds introduced into the delivery conduit 20 are transported
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therealong by the pressurized air to the lower end of the
delivery conduit 20 where they exit into a furrow prepared by
a coulter or other suitable mechanism to which the seeder is
attached.
As shown in Figure 1 the seeder 22 includes a hopper
24 which contains the seeds 26 to be planted. At the exit from
the hopper a feed wheel 28 is provided which wheel has means
such as studs or flutes 30 around the periphery. The studs
define therebetween pockets which~ as the wheel 28 rotates,
pick up seeds from the hopper and deposit them at a rate
determined by the stud spacing and the rotation speed into the
entranceway 32 of the delivery conduit from which they are
transported pneumatically to the planting site. Other feed
mechanisms are well known and the present invention may be used
therewith, such other mechanisms including rubber rollers,
augers, belts or agitators.
It is clear that if there is a failure of the pneu~atic
system and the feed means as described continues to operate,
the passage of seeds through the delivery conduit 20 could slow
down to the point where the fed seeds can no longer pass through
the delivery conduit and the accumulated seeds plùg the delivery
conduit.
The present invention involves the addition of certain
equipment to the basic air seeder structure. Specifically, as
shown in Figure 2 a pressure-sensitive electrical transducer
such as a piezo-electric transducer 34 is located in the blower
outlet 16 so as to sense the presence of pressurized air from the
outlet 16. The transducer 34 should be positioned in such a
manner that the pressure sensed thereby is maximized. A wire
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36 extends from the transducer 34 to a depth control switch 38
the purpose of which will be described hereinbelow. With the
switch 38 actuated an electrical signal from the transducer 34
is transmitted via the amplifier 40 to a control device such
as solenoid 42 located adjacent the drive mechanism for the
feed wheel 28.
A clutch mechanism, such as a spring-wrap clutch 44
(well known in the agricultural field) is positioned between
the power source (not shown) for the feed wheel 28 and the
wheel 28 itself, preferably on a drive shaft 46 for the feed
wheel 28.
The clutch 44 is intended to be controlled via the
solenoid 42 and to that end the movable armature 48 extending
from the solenoid is pivotally connected as at S0 to one leg 51
of a lever arm 52, the other leg 53 of which extends at right
angles to the leg 51, the lever-arm 52 being pivotally connected
to the seeder structure as at 54. The leg 53 carries a dog 56
for cooperation with a correspondin~ dog or tang 58 on the
spring of the clutch 44 such that when the dogs 56, 58 are
apart the spring of the clutch will wrap down to connect the
drive with the feed wheel so as to permit operation of the feed
wheel 28.
- Insofar as the switch 38 and its function is concerned
it should be understood that air seeders are usually assembled
to and are used in conjunction with mechanisms such as coulters
or cultivators which prepare the soil for reception of the seed,
as by preparing a furrow to a required depth. Thus the seeder
should operate only when the furrow, or the equipment creating
the furrow, is at the correct depth relative to a predetermined
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datum such as the ground surface. Also, such equipment usually
is pivotable away from the ground surface to provide adequate
clearance for transportation purposes. The switch 38 is
provided and operates so as to ensure that the seeder feeds
seeds for planting only at the correct time, that is when the
coulter or other preparation device is at the correct depth.
By using the switch 38 in conjunction with the electrical feed
control of this invention, improvements in flexibility,
versatility and cost effectiveness are achieved since, in the
past, the mechanical systems which controlled the feed mechanism
in conjunction with the raising and lowering of the cultivator
were complex, bulky, expensive and awkward in use.
In the drawings the switch 38 is shown schematically
only since varioue types of commerically available switches
could be used. Also, the connections and devices which effect
operation of the switch are shown schematically only since such
will depend on the equipment configuration being utilized and
the exact structure thereof does not form a part of this
invention.
The switch 38 has two conditions, namely "on" or
"off". When in the "on" position current from the transducer
34 is permitted to reach the amplifier 40, such current flow
being prevented when the switch 38 moves to its "off" position.
The switch 38 will be in its "on" position only when the ground
is ready to receive seeds, namely when the seeder equipment is
positioned at the correct depth. When that position has been
reached, as determined by the remote position sensor 60 the
switch 38 is moved from its "off" to its "on" position. The
remote sensor 60 could be electrical in nature, as a micro
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switch or a proximity sensor, in which case the switch 38
could be an electrically operated solenoid switch. The remote
sensor 60 could be mechanical in nature, in which case suitable
linkages could connect the sensor 60 to a suitable mechanically
operated version of the switch 38. In either case any movement
of the seeder away from the correct depth, as by encountering a
situation causing the seeder to raise,will cause the sensor 60
to detect such movement and to thereby cause the switch 38 to
move from its "on" to its "off" position. The switch 38 could
be, for example, spring loaded so that a breaking of the current
normally passed thereto by an electrical sensor 60 will cause
the desired switch movement, or, if mechanical, the linkages
connecting the switch 38 to the sensor 60 could themselves move
the switch to its "off" position.
The operation of the invention according to Figure 2
.:
should be readily apparent from the foregoing. With the seeder
at the correct depth and the switch 38 at its "on" position
the transducer 34 will sense sufficient pressure from the blower
10 to transmit an electrical current through the switch 38 to
the amplifier 40 which in turn provides sufficient current to
the solenoid 42 so as to force the armature 48 thereof dcwnwardly
(as in Figure 2).
That position is shown in Figure 2 wherein the lever
arm 52 has pivoted about the pivot 54 so that the dogs 56, 58
are disengaged. As described above the lack of engagement
between the dogs 56, 68 permits the spring of the clutch 44 to
wrap down so as to connect the input member of the clutch (the
drive means) with the output mem~er of the clutch (the feed
wheel 28) directly or indirectly.
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Should the blower 10 stop functioning for any reason
the pressure sensed by the transducer 34 will no longer be
sufficient to sustain the amplified current required to operate
the solenoid 42. The armature 48 will retract aided by the bias
of an internal spring to thereby cause the lever arm to pivot
about 54 and the dogs 56, 58 will be brought into engagement,
causing the spring of the clutch to open thereby stopping the
transmission of power to the feed wheel. Thus should there be
a failure in the air supply the feed mechanism will immediately
cease to function and no more seeds will pass into the delivery
conduit 20.
Should the seeder be raised from its operative
orientation even though there be no failure of the air supply
the switch 38 will be moved from its "on" position to its "off"
position as described above, thereby causing a cessation of
current transmitted to the amplifier 40 and the solenoid 42 and
causing the clutch 44 to stop the feed wheel 28 as described above.
Figure 3 shows an embodiment similar to that of
Figure 2 but with the addition of a remote control switch 62
in the line 36. The switch includes an actuator 64 which is
operable by the machine operator. Should the operator wish to-
stop the feed wheel 28 he could operate the switch 62 so as to
interrupt the flow of current in line 36, thereby causing the
solenoid 42 to be deactivated, thereby causing the clutch to
stop rotation of the feed wheel 28. By providing the switch 62
the present invention thus permits either automatic or manual
control of the feed wheel 28. This feature is advantageous
when the operator wishes to till the soil without seeding or
depositing any material while a seeding or depositing operation
is otherwise underway.
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Figure 4 illustrates another embodiment of the
present invention. In this instance the transducer 34, the
depth control switch 38 and the remote control switch 62
are connected in such a manner that when they are all
switched to an "on" or operating position they trigger a
logic circuit 66 (such as an AND gate) which in turn pro-
vides current to the amplifier 40 and solenoid 42 so as to
effect the desired clutch operation.
In the drawings the circuitry relating only to
the operative units of the invention has been illustrated.
It is understood that a D.C. or an A.C. power source will
be required for the amplifier and the various solenoids.
A positive or negative power supply can be utilized and
since the necessary connections therefor will depend on the
application and are well within the expertise of a skilled
electrician it is not deemed necessary to illustrate the
power supply and its connections.
The foregoing describes the invention utilizing
a solenoid 42 which is energized so as to maintain the
clutch in its engaged condition to effect drive of the feed
wheel. It would be possible, within the ambit of the
invention to utilize a solenoid and an appropriate trans-
ducer in such a manner that clutch engagement is maintained
when the solenoid is not energized and so that energization
of the solenoid will result in disengagement of the clutch
and thereby disconnect the seed wheel from its drive. In
this case the solenoid would be oriented so that its
spring bias keeps the dogs 56, 5~ out of engagement and when
energized the armature would move so as to bring the dogs
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56, 58 into engagement so as to disengage the clutch. For
this embodiment the transducer 34 could be a normally-open
microswitch connected to a pressure-sensitive diaphragm
at the blower outlet 16 which would close to complete the
electric circuit should there be a drop in pressure.
A diaphragm operated normally-closed micro-
switch could be used as a transducer in the other embodi-
ments wherein a constant electrical signal is used to elec-
trically operate the solenoid 42 to maintain the clutch in
its engaged condition.
The above provides the best description of the
invention as presently available but it is understood that
variations therein could occur to someone skilled in the
art without departing from the spirit of the invention.
Accordingly, the~scope of protection to be afforded the
invention is to be determined from the claims appended
hereto.
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