Note: Descriptions are shown in the official language in which they were submitted.
CA 02254801 1998-11-30
Doc. No. 36-14CA Patent
Sprayer Including Hydraulic Drive for Controlled Sequential Unfolding
Operation
Field of the Invention
The present invention relates to an agricultural sprayer, and a method and
apparatus for hydraulic control providing sequential unfolding operation of
the sprayer
between a transport position and an operational position.
Background of the Invention
Sprayers are trailer devices for applying liquid chemicals to a field surface.
The
sprayer includes a central cart for supporting the supply tanks and a pair of
hinged booms
or wings which support nozzles in spaced apart arrangement connected to the
supply
tank. The nozzles and associated chemical supply lines are carried on a
secondary boom
rotationally supported on the primary boom at the rear of the device in the
operational
direction. The primary boom is in rolling contact with the ground on caster
wheels and
carries the hydraulic operational drive lines.
The wings are arranged in transverse position in operation to deliver chemical
to a
wide path with each pass. In operation the nozzles are directed downward
toward the
ground surface and may be shielded by windscreens. For transportation when not
in use,
the long wings fold behind the central cart with the nozzles, supply lines and
windscreens
of the two booms positioned adjacent each other. To avoid damage to the
nozzles etc.,
the secondary booms are rotated up above the main booms prior to folding the
wings.
Hydraulic drive lines powered by the towing tractor are used to operate the
setup and take
down sequence between the transport position and the operational position.
Traditionally the wings have been moved between operational and transport
positions by reversing or advancing the tractor and allowing rolling
resistance against
castered wheels to move the wings. To remove the reversing step, in
particular, a second
hydraulic drive has been provided to open the wings to a transverse
operational position.
While this greatly assists in setup procedure, the addition of a second
hydraulic circuit for
the setup procedure is not convenient. Tractors have a limited number of
spools or
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hydraulic controls. Sometimes a tractor may have 3 or 4 spools, but more
commonly a
tractor has only two spools, both of which may be needed for the sprayer pump
and a
hydraulic disc marker. Thus a hydraulic unfold drive requiring two spools,
would also
require additional expensive upgrades.
The booms are quite long and heavy increasing the risk of damage in the event
of
mishap or error. When the booms are folded back into a transport position, the
tractor is
driven forward and the booms are released and allowed to swing back. If the
secondary
booms have not been positioned correctly, the heavy weight of the booms will
collide at
the windscreens, and nozzles causing expensive damage.
Problems may also be encountered if the hydraulic unfold cylinder is not
extended
after use. For instance a break away linkage cannot release the boom if an
obstacle is hit,
because the boom pivot linkages are in a fixed position, and pressure to the
cylinder
causes it to act as a rigid link. If the unfold cylinder is correctly
positioned, the break
away linkage would allow the boom to fold back. The result of the error in the
unfolding
sequence would be damage to the boom itself, or to the linkages. Similar
problems
would also be encountered if the operator attempts to fold the booms to the
transport
position. Just as in the break away situation, the cylinder under pressure in
the retracted
position provides a rigid link securing the pivot linkages in a fixed
position. Then if the
operator drives forward to fold the booms, significant pressure would be
placed on the
linkages and the unsupported booms.
In prior hydraulic setup drives including two hydraulic circuits it was
necessary
for the operator to first operate one tractor hydraulic lever to start the
unfold cycle
unlocking the locking caster to the wheels, then switch to the unfold drive to
unfold the
booms, remembering afterward to reset the cylinder to the transport position,
and then
switch back to the initial lever to position the nozzles. These steps must all
be carried out
in the necessary sequence to prevent mishap. Since two separate hydraulic
drives were
used, the sequence of operation of one drive line did not affect the operation
of the other,
consequently steps could be missed.
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CA 02254801 2005-04-08
It is desired to reduce the demands for tractor hydraulic controls and to
prevent
inadvertent errors in operation sequencing, while still providing the
advantages of
hydraulic fold and unfold operation.
Summary of the Invention
The present invention has found that a single hydraulic control can drive the
unfolding and height adjustment circuits in parallel. In a preferred circuit
this can be
accomplished using pressure responsive valves to ensure a correct setup
sequence.
In accordance with the invention there is provided an agricultural sprayer
including: a) a pair of pivotally mounted wings comprising main booms
pivotally
movable between an aligned transport position and a transverse operational
position and
supported on caster wheels having wheel locks and secondary booms carrying
spaced
spray nozzles and rotatably secured on the main booms for selective height
adjustment to
1 S a field position; b) caster wheel lock release means to allow said wheels
to caster and said
wings to move pivotally between said transport and operational positions; c) a
hydraulic
unfold cylinder operably connected to said wings via linkages for pivotally
unfolding and
moving the wings from the aligned transport position to the transverse
operational
position; d) hydraulic rotator cylinders connected to rotate the secondary
booms relative
to the main booms; and e) a hydraulic drive system operatively connected to
said lock
release means, said unfold cylinder and said rotator cylinders and adapted to
effect the
ordered steps of i) releasing the caster wheel locks, and then ii) actuating
the hydraulic
unfold cylinder to unfold and move the wings to the operational position; and
then iii)
activating the hydraulic rotator cylinders to rotate the secondary booms to a
field
position.
Another aspect provides a sprayer including hydraulic drive for operating a
setup
sequence through a single hydraulic circuit comprising: a pair of pivotally
mounted wings
movable from a transport position substantially aligned with a direction of
travel to an
operational position substantially transverse to a direction of travel
including main booms
supported on caster wheels, the caster wheels including wheel locks for
limiting their
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CA 02254801 2005-04-08
range of motion, and secondary booms for supporting spray nozzles secured for
pivotal
movement on the main booms for selective height adjustment; a first loop of
the
hydraulic circuit; a cooperating pair of hydraulic rotator cylinders for
rotating the
secondary booms hydraulically driven by the first loop; a second loop of the
hydraulic
circuit interconnected with the first loop; and, an unfold cylinder for
drawing the wings
from the transport position to the operational position hydraulically driven
by the second
loop; means for restricting flow into the second loop until drive is stopped
in the first
loop; and means for restricting a return flow into the first loop until drive
is stopped in
the second loop.
Another aspect provides a method for hydraulically unfolding an agricultural
sprayer from an aligned transport position to a transverse operational
position, the sprayer
including a pair of wings comprising main booms supported on caster wheels
including
mechanical wheel locks, and secondary booms for supporting spray nozzles
secured for
pivotal movement on the main booms for selective height adjustment through a
single
hydraulic circuit arranged in parallel loops, a first loop controlling a pair
of rotator
cylinders for adjusting the height of the secondary booms, a second loop
controlling an
unfold cylinder for unfolding the wings, and a pressure responsive valve
separating the
first and second loops, the method comprising the ordered steps of: providing
sufficient
pressure to the first loop to rotate the secondary booms for releasing the
caster wheel
locks; allowing pressure in the first loop to increase until the pressure
responsive valve
releases to provide pressure to the second loop retracting the unfold cylinder
and
unfolding the wings; reversing the hydraulic drive into the second loop to re-
extend the
unfold cylinder and reset the pressure responsive valve; reversing the
hydraulic drive
again to provide hydraulic drive into the first loop for lowering the
secondary booms into
field position.
Advantageously, a sprayer including the hydraulic controlled setup sequence of
the present invention provides simple, accurately sequenced operation
requiring only one
hydraulic spool of the tractor. In addition, the setup can be accomplished in
less time,
requiring less space.
3a
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Additional advantages will be understood to persons of skill in the art from
the
detailed description of preferred embodiments, by way of example only, with
reference to
the following figures:
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Brief Description of the Drawings
Figure lA illustrates a sprayer in plan view in the transport position;
Figure 1B illustrates the sprayer of Fig. lA in plan view in the operational
position, one
wing is not shown;
Figure 1C illustrates a sprayer in plan view with one boom in operational
position and
one boom in a fold back position;
Figure 2 is a plan view of a sprayer boom lock valve for controlling rotation
of the
secondary booms;
Figure 2A illustrates a front view of the cam mechanism from line A-A of Fig.
2;
Figure 3 is an isometric view of a wheel lock operated by rotation of the
secondary
booms;
Figure 4 is a partial plan view of a sprayer and cart illustrating the unfold
cylinder in a
retracted position;
Figure 5 illustrates the view of Fig. 4 showing the unfold cylinder in an
extended
position;
Figure 6 is a partial plan view of one of the boom pivot linkages and the
unfold cylinder
in an extended position;
Figure 7 illustrates the view of Fig. 6 showing the cylinder in a retracted
position during
set up operation;
Figure 8 illustrates the view of Fig. 7 showing the cylinder in an extended
position and
the boom and linkages in operational position;
Figure 9 illustrates a preferred embodiment of the automated hydraulic circuit
for
operating the set up sequence, in accordance with the present invention; and,
Figure 10 illustrates an alternative preferred embodiment of the automated
hydraulic
circuit including a fold back control valve.
Like numerals are used throughout to indicate like elements.
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Detailed Description of Preferred Embodiments
Figures lA and 1B show a sprayer 10 generally in transport and operational
position at 10. The sprayer 10 includes a central cart 12 with a draw bar and
hitch 14 for
towing by a tractor (not shown). The cart 12 supports supply tanks 16. A pair
of wings
18 are pivotally connected to the cart 12 at brackets 20. The right wing (not
shown in
Fig. 1 B) is symmetrical to the left. Draw tubes 22 are locking arms which
support the
wings 18 in transverse operational position as the assembly is towed forward.
The
direction of travel is indicated by arrow V. The close alignment of the right
and left
wings 18 in the transport position is visible in Fig. 1 A.
The wings 18 consist of a primary boom 24 carried on caster wheels 26 and a
secondary boom 28 supported on the primary boom 24 for rotational movement
about an
axis parallel to the primary boom 24 by boom rotator cylinders 80. The
secondary boom
28 carries chemical supply lines, including spray nozzles spaced at regular
intervals and
optional windscreens 30 to the rear of the primary boom 24 in the operational
direction of
travel. The wings 18 are opened to the operational position by the retraction
of a
hydraulic unfold cylinder 60, seen clearly in Fig. 4-8.
Some or all of the caster wheels 26 include wheel locks 40. An example of a
preferred wheel lock 40 is shown in detail in Figure 3, for locking the wheels
26 in
forward rolling position to force the trailing wings 18 to follow straight in
the transport
position behind the tractor and cart 12. The wheel lock 40 includes a cam 42
secured to
the secondary boom 28. As the secondary boom 28 is rotated, the cam 42 acts on
follower lever 44 to lift the locking pin 46 from locking plates 48 associated
with the
wheel mount 50. When the locking pin 46 is raised, wheel 26 is free to caster
for set up
and operation.
Since judging the secondary boom rotation from the tractor has proven
difficult, a
depth stop is provided comprising a boom lock valve 100 to stop the hydraulic
drive to
the rotator cylinders 80 once the wheel locks 40 have been released. This
stops
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secondary boom rotation preventing a crash between the closely spaced
secondary booms
28.
The boom lock valve 100, seen in detail in Figure 2 is also secured to the
secondary boom 28 and is responsive to the rotational position of the
secondary boom 28.
The primary boom 24 supports hydraulic drive lines 120 for boom rotation
operation
including a valve 102 which provides an intermediate stop function to prevent
a crash
between secondary booms 28. If the sprayer 10 is so dimensioned that no risk
is
presented of the secondary booms 28 contacting each other, such a stop is not
needed.
The secondary booms 28 would rotate to a fully extended position and stop
which would
also result in a rise in pressure in the hydraulic circuit. Alternatively an
intermediate
stop can be a mechanical abutment with a release, or an electrically
controlled device.
Preferably the stop valve 102 is a poppet valve including a projecting
actuator pin
104 as illustrated. An actuating lever 106 is moveable pivotally on hinge pin
105
mounted on the primary boom 24 and is biased toward the valve actuator pin 104
by
spring 108. A cam 110 is secured for rotation with secondary boom 28. Lever
106
includes an angled surface 107 in sliding engagement with angled surface 111
of cam
110. As secondary boom 28 and cam 110 are rotated, angled surfaces 107 and 111
slide
and actuating lever 106 is drawn by the biasing spring 108 against valve
actuator pin 104
closing the valve 102 and stopping the rotational drive. Cable 112 is secured
to the
supporting bracket 20 at a front end (not shown) and to actuating lever 106
opposite the
biasing spring 108. Due to a slight angle between end points of the cable, as
the wings 18
are opened to the transverse operational position, the cable 112 is drawn
tighter releasing
the actuating lever 106 from the actuator pin 104 opening valve 102. Pressure
to the
hydraulic lines 120 again restores hydraulic drive to the rotator cylinders 80
resetting the
valve 102. With hydraulic drive re-established, the nozzles and windscreens 30
can be
lowered behind primary boom 24 for operation.
Other wheel lock mechanisms are known, such as disclosed in U.S. Patent No.
4,944,355 issued to Brandt Industries Ltd., which includes additional
hydraulic cylinders
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for caster wheel control, or other mechanical wheel lock mechanisms which can
be
incorporated in the present unfold operation control. The present invention
for providing
a single circuit for unfolding the wings 18 and rotation of the secondary
spray booms 28
could be used in combination with such other caster wheel controls.
To operate the sprayer 10 correctly, it is necessary to follow a sequence of
set up
and fold operations for changing from transport to operational position and
back again.
Many of the steps are automated by the drive circuit in accordance with the
present
invention. To review the process, the sequence is outlined below.
The setup unfolding sequence from a transport position to an operational
position
first requires the wheels 26 to be unlocked by a cam 42 operated by partial
rotation of the
secondary booms 28, to permit them to freely caster. A stop means such as a
hydraulic
valve 102 stops rotation of the secondary booms once the wheels 26 have been
released.
The wings 18 are advanced to their transverse position by a separate hydraulic
unfold
cylinder 60 (shown in Figs. 4 and 5). The stop valve 102 is released when the
wings 18
reach a fully open position. The unfold cylinder 60 is then re-extended to its
position for
operation. Then rotation of the secondary booms 28 is completed to lower them
into
operational position. Once the secondary booms 28 are lowered, cables 68
permit locks
70 to lock the draw tubes 22 in position to support the booms 24 in operation.
The unfold cylinder 60 and linkages are shown in detail in Figs. 4-8 in
different
positions. Seen in Fig. 4, fold cylinder 60 is fully retracted as the wings 18
reach the
transverse unfold position. Unfold linkages include a boom rotation pivot 62
pivotally
securing the boom 24 to the draw bar brackets 20 of the cart 12 frame. A crank
arm 64
comprises three elements 64a, 64b, and 64c, pivotally linked together for
extension or
retraction. Abutting crank arm elements 64a and 64b rotate together around a
fixed crank
pivot 66 as a lever arm pulling element 64c pivotally secured to the boom 24
behind the
rotation pivot 62. Cylinder 60 pivotally connected to element 64a retracts
acting on the
crank arm elements 64a and 64b to lever against the crank pivot 66 rotating
the boom 24
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about the boom rotation pivot 62 to a transverse position. As seen in Fig. 4,
cylinder 60
acts simultaneously opening both booms 24 through symmetrical linkages.
Once in the transverse position, booms 24 are secured by draw tubes 22 at
locking
pin 70 on the cart 12 for operation. The draw tube 22 also includes a break
away release
securing it to the boom 24 for emergency release. In a retracted position
shown in Figs. 4
and 7, pressure within the cylinder 60 would form a fixed link which would
prevent
wings 18 from folding back with a break away release if an obstacle is struck.
The
cylinder 60 is re-extended, as shown in Fig. 5, before operation. When the
cylinder 60 is
in the extended position, crank arm 64 is collapsed into a folded position,
shown in Fig.
8. From this position the wing 18 can fold back pivoting about boom pivot 62,
if
necessary.
To return to a transport position from an operational position, the folding
sequence involves rotating the secondary booms 28 from a downwardly directed
position
to an upwardly directed position. This releases the draw tube locks 70 via
cable 68. Once
the secondary booms 28 have been raised, the sprayer 10 is advanced and the
primary
booms 24 are folded back into a trailing position with the secondary booms 28
of each
side adjacent each other. The booms 24 are aligned closely together to conform
to a
dimension which can be trailed on the highway. It is essential to raise the
secondary
booms 28 before closing the primary booms 24 as the close position in
transport would
cause the secondary booms 28 to crash together. The rotation of the secondary
booms 28
thus also assists in adapting the device to a sufficiently narrow transport
position.
As the sprayer is driven forward, the booms 24 close into the trailing
transport
position, and the wheels 26 are automatically locked in a forward rolling
position by a
cam (shown in detail in Fig. 3) which positions a locking pin 46 in
cooperating support
plates 48. This is necessary for the booms 24 to trail straight behind the
tractor and cart
12. Depending on the length of the booms 24, the number of wheels will vary.
For very
long booms, only the intermediate wheels 26 are locked, while the rear wheels
are still
free to caster.
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To provide this automated operation for unfolding the sprayer wings,
activation of
a single hydraulic circuit, shown in Fig. 9 sequentially drives the unfold
cylinder and
rotational control cylinders. The hydraulic control circuit shown in Fig. 9
includes lines
A and B for hook up to a tractor spool. The circuit includes a first loop 120
providing
fluid drive to a master and slave pair of rotator cylinders 80 which respond
simultaneously. Within the loop 120 is the stop valve 102 for severing flow
within the
first loop 120, once the wheel locks have been released. A second loop 122,
interconnected with the first loop 120, provides fluid drive to the unfold
cylinder 60. A
sequence valve 90 remains closed preventing flow into the loop 122 until the
stop valve
102 is closed and the pressure increases in loop 120 to a preset level, for
example 1750
psi. Once open, sequence valve 90 allows free flow to a throttle check valve
94 which
slows the rate of flow to retract the unfold cylinder 60. This slows opening
the wings to
about 5 - 10 seconds reducing momentum and the possibility of damaging the
wings.
The throttle check valve 94 allows free flow in reverse. The sequence valve 90
includes
an internal check, or an external check valve is provided, to provide
unrestricted flow in
the reverse direction. Loop 122 joins line A bypassing the stop valve 102 at a
T junction.
Loop 122 also includes a relief valve 92 bypassing the unfold cylinder 60. The
sequence
valve 90 could be replaced by a lower pressure relief valve, if the pressure
to unlock the
casters is reduced. This circuit provides the desired sequential operation,
with minimal
valves and controls.
Operation of the hydraulic drive proceeds as follows: Line A and line B are
used
to identify a cooperating pair of hydraulic lines connected to a single
tractor control for
forward and reverse drive within the hydraulic circuit. Pressure input to line
B provides
hydraulic flow which activates the boom rotator cylinders 80. This rotates the
secondary
booms 30 degrees from a position approximately 15 degrees over center to a
position
approximately 15 degrees below vertical where a stop valve 102 severs
hydraulic flow
and stops rotation. Rotation of the secondary booms 28 at this stage releases
the wheel
locks 40 to the caster wheels 26. Actuation of these cylinders 80 occurs first
because the
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pressure to move these cylinders 80 is less than the preset pressure to open
the sequence
valve 90.
Pressure to line B continues to increase within the rotator cylinder loop 120
of the
circuit only, until sufficient pressure releases sequence valve 90 allowing
hydraulic drive
to the unfold cylinder loop 122. The unfold cylinder 60 is retracted,
initiating unfolding
pulling the booms 24 into the transverse operational position. As the booms 24
approach
a fully unfolded position, a cable 112 releases the stop valve 102 restoring
hydraulic
drive line to the boom rotator cylinders 80. Drive to line B is shut off by
the operator
when the booms 24 are fully open, or by an automatic pressure responsive
detent at the
tractor control. Valve 90 resets itself when flow through loop 122 stops.
Pressure is applied to line A once the main booms 24 are unfolded. This
provides
a reverse flow which first re-extends the unfold cylinder 60, because
resistance from the
rotator cylinders 80 is higher. The means used to direct drive to re-extend
the unfold
cylinder 60 could be a number of mechanisms, for instance the stop valve 102
prevents
flow through loop 120, or even without the stop valve 102, the resistance may
be higher
in the rotator cylinders 80 than that of cylinder 60, causing cylinder 60 to
re-extend,
because the secondary booms 28 are tightly journaled and resist rotation, or
because in an
over center position the weight of the secondary booms 28 creates a higher
resistance on
cylinders 80. The sequencing valve 90 includes an internal check to allow free
reverse
flow to re-extend the unfold cylinder 60. Pressure continues to increase
actuating the
boom rotator cylinders 80 causing the secondary booms 28 to rise again
signaling the
operator to stop the drive to line A.
Pressure to line B again extends the rotator cylinders 80 lowering the
secondary
booms 28 into field position. This rotation lowering the booms acts on a cable
68 to
permit the draw tube lock pins 70, which are spring biased, to lock the draw
tubes 22 for
operation. The draw tube locks 70 only engage when the secondary booms 28 are
lowered to a set level. The operator may reverse the sprayer 10 enough to
ensure that the
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draw tubes 22 engage the locks and the sprayer 10 is ready for operation. Once
the
operational position is reached the operator manually disengages the tractor
control
immediately after the booms are lowered.
In field operation, adjustment to the operational position of the secondary
booms
28 and nozzles etc. can be made without opening the sequencing valve 90.
It is sometimes desired to operate with only one boom 24 in operational
position,
and the other boom 24 in a fold back position as shown in Fig. 1 C. To do so,
once the
secondary booms 28 have been lowered into field position, the operator leaves
the tractor
to adjust the isolator valve 140 shown in the circuit in Fig. 10 to cut off
hydraulic flow to
one of the rotator cylinders 80. The operator then begins a fold operation as
if returning
to transport position. Since no drive reaches the isolated cylinder 80, it
remains in its
operational position. The secondary boom 28 of the other wing 18 is raised
unlocking the
draw tube 22. The operator drives forward causing the wing to fold back, and
the wheel
lock 40 to engage in a forward rolling position. Advantageously, this wing 18
can now
be unfolded and refolded again using the hydraulic unfold circuit, without
readjustment
of the valve 140. The valve 140 may conveniently include a solenoid or other
means for
remote electrical control. The fold back operation may be incorporated in
either wing 18.
If the sprayer 10 is mistakenly advanced before the complete sequence has
occurred and the unfold cylinder 60 has not yet been re-extended, the risk of
damage to
the booms 24 is alleviated by a relief valve 92 which allows the flow to
bypass the unfold
cylinder 60 at a selected pressure permitting the boom 24 to fold back. The
relief valve
92 is not essential to obtain the sequenced operation of the hydraulic drive.
To fold the wings 18 again into transport position, pressure to line A rotates
the
secondary booms up to a position approximately 15 degrees over center.
Rotation raising
the secondary booms 28 causes a cable 68 to act on the draw tube lock pins 70,
disengaging the draw tubes 22. The operator then moves the sprayer 10 forward
causing
the wings 18 to swing rearwardly. The wheel locks 40 engage the caster wheels
26 for
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forward rotation. The operator will further connect a manual transport lock
before
transporting the sprayer 10 on major roadways.
In this hydraulic circuit the sequencing valve 90 used, once opened, allows
free
flow. The opening pressure may be fixed or adjustable. A preferred embodiment
contemplated uses an opening pressure of 1750 psi. This pressure is selected
to provide
sufficient force to rotate the secondary booms 28 against gravity from an over
center
position to a position past vertical. Depending on the size and journal
resistance of the
booms 28 this may require up to 1200 psi. Once past the vertical position,
little pressure
is required to lower the booms 28 farther.
Flow to the unfold cylinder 60 from line B is restricted by a throttle check
valve
94 slowing the movement of the cylinder 60 in order to move the wings 18 in a
slow
controlled operation. In a reverse direction from line A, the throttle check
valve 94
allows free oil flow while the unfold cylinder 60 is re-extended.
For the operator, these sequences are carried out by following three steps:
a. Initiating pressure to line B unlocking the wheel locks and unfolding the
booms, and disengaging the drive;
b. Initiating pressure to line A which reverses the flow resetting the unfold
cylinder, and disengaging the drive; and,
c. Initiating pressure to line B again, lowering the secondary booms to field
position, and disengaging the drive.
Advantageously, the hydraulic circuit can be configured to force the operator
to perform
these three steps in sequence without error. In the preferred circuit step a.
initially finds
the rotator cylinders 80 fully retracted, providing no response if the wrong
drive is
initiated. Once step a. is completed drive to line B is stopped by valve 102
in loop 120
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and cylinder 60 is fully retracted, thus further drive is not possible from
line B.
Operation cannot skip step b to further pressurize line B, as in step c.
because the stop
valve 102 must be reset by the pressurization of line A provided by step b.
Other means can also be used to cause the interlinked circuits to provide the
sequential
setup operation. For instance, other caster lock mechanisms could be used or,
the stop
valve could be replaced by a mechanical stop. Loads on the actuating cylinders
also
affect the sequence of operation. These loads can be balanced so that no
sequence valve
is necessary.
Of course, numerous other embodiments may be envisaged, without departing from
the
spirit and scope of the invention as defined in the appended claims.
13
