Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
HYDRAUI.IC CONTROL CIRCUIT FOR ~ MASTER
CYLII`~DER WITI-I MULTIPLE LIMIT POSITIONS
Field of the Invention
The present invention relates to control circuits
for hydraulic cylinders; and it has particular application
in hydraulic circuit~ having a mas-ter cylinder and one or
more slave cylinders wherein the master cylinder may be
extended to additional limit posi-tions after the slave
cylinder is fully extended.
Backqround and Summary of the Invention
By way of example, an hydraulic circuit of the
type with whlch the present invention is concerne~ is used
in the agricultural planter disclosed in my United 5tates
Patent No. 4,738,315 entitled ~Agricultural Planter". The
planter disclosed in that patent is a large agricultural
planter having a lift frame which may be elevated relative
to a carrier frame to two different positions o~ elevation.
In the firs-t or lower elevated position, the lif-t frame
raises -the individual planter units out of the planting
position so that the planter may turn at the end of a field.
This first height for the lift frame not only removes the
individual planter row units from engagement with the
ground, but it disengages the drive system for the seed
meters. Otherwise, the meters would continue to meter out
the seed, fertilizer and insecticide.
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31L2~ 2
The hydraulic c;rcuit for raising the lift frame
to this first position includes a master cylinder cooperating
with at least one slave cylinder. Actually, there are two
such hydraulic circuits in the planter, one on the right
side and one on the left side, but they are similar in
structure and they function together.
I~hen the hydraulic cylinders elevate the lift frame
to the end turn position, the slave cylinders have reached
full extension, but the master cylinder has not. The master
cylinder may be further extended to elevate the entire lift
frame (in which case, the wings of the lift frame are locked
to the center section, and the master cylinder is further
extended) to a second, higher position. At the second limit
position of the master cylinder, the entire lift frame may
be rotated 90 about a vertical axis so that it extends
parallel to the direction of travel of the tractor for road
transport.
It will thus be apparent that the farmer raises
the planter to the first limit position of the master
cylinder (i.e., for an end t~rn) many more times than he
raises the master cylinder to its second limi~ position for
road transport.
A conventional type of hydraulic control valve
in the tractor (sometimes called the nmain valYe~ or
~selective control valven) used by the ~armer for these
control unctions has a Jaechanical deten~ or ma;ntaining
the operating lever in the ~up~ position, until a sharp
increase in pressure, as occurs when the slave cylinaers
reach the limits of their extension~ is sensed ~y the control
valve to kick the lever out of the detent posit;on and lock
up the hydraulic system at that time, E~owevert for a number
~z~
of reasons, and for certain types of hydraulic systems,
depending upon the manufacturer of the tractor, for example,
operation of the hydraulic system has not reliably disengaged
the operating lever from the detent at the first limit
position for end turns. If disengagement of the control
valve at the first limit position does not occur reliably,
the operator must continually direct his attention to the
planter to ensure that it does not elevate to the road
transport position. Thus, it is important to actuate the
lQ selective control valve and release it from detent in a
reliable manner ~hen the master cylinder has reached its
first limit position; ànd the present invention has, as a
principal objectivè, that purpose.
The present invention provides a separate auxiliary
discharge conduit with a solenoid-actuated control valve
having a normally closed position. The auxiliary discharge
conduit is located in the hydraulic circ~it so as to permit
the master cylinder to extend from its first limit position
to its second limit p~sition only ~;hen the solenoid valve
20 i5 opened. Thus, ~:hen the main control valve is placed in
detent the first time, the master and slave cylinders extend
until the slave cylinaers are fully extended. Conventional
rephasing ports at the rod end of the slave cylinders are
eliminated, so that ~hen the slave cylinders are fully
extended, and the auxiliary discharge cond~it is closed,
pressure increases rapidly and the resulting pressure ~spike~
releases the main control valve from its detent position~
This, of course, d;sconnects the hydraulic pump fror~ the
cylinders and locks the hydraulic cylinders in placeO
~2~
If the operator wants the master cylinder to extend
from its first limit position to a second limit position,
he opens the solenoid-actuated valve and again operates the
main control valve to extend the master cylinder. During
this operation, the slave cylinders remain fully extended,
and hydraulic fluid is discharged from the ro~ end of the
master cytinder thro~gh the auxiliary discharye conduit
because the solenoid-actuated valve is open; and the
hydraulic fluid returns to the hydraulic reservoir or the
return port of the pump.
Thus, the system insures that the selective control
valve on the tractor will be released from detent when the
slave cylinders are fully extended at the first limit
position of the master cylinder so that the operator need
not be concerned when he raises the planter for an end turn.
Yet the master cylinder can be extended even further to a
second li;nit position ~ en desired to elevate the lift fral~e
to the transport position.
other features and advantages of the presc-nt
invention will be apparent to persons skilled in the art
from the following detailed description of a preferred
embodiment accompanied by the attached drawing wherein like
reference numerals will refer to similar elements in the
various views.
Brief Description of the ~rawin~
FIG. 1 is a plan view of an agricultural planter
in which the present invention is exemplified~ with some
of the elements remcved for clarity;
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35~
FIG. 2 is a right side close-up view of the master
cylinder and linkage for raising the lift frame of the
planter of FIG. l;
FIG. 3 is a broken away plan view of the elevating
mechanism of FIG. 2;
FIG. 4 is an hydraulic schematic circuit diagram
for the control system for raising the lift frame;
FIG. 5 is a view of the hydraulic control system
with the master cylinder in the first limit position; and
FIG. 6 is a diagram of a hydraulic control system
with the master cylinder in the second limit position.
Detailed Description of the Illustrated Embodiment
To facilitate an explanation and understanding,
the invention will be illustrated in combination with an
agricultural planter, but the particular planter shown is
not a necessary part of the invention since the invention
could be used with other agricultural implements and is not
even limited to agricultural applications, as p~rsons skilled
in the art will appreciate from a complete understanding
of the invention.
Referring to FIG. 1, the present invention is
illustrated in the context of a planter generally designated
by reference numeral 10 and adapted to be pulled by a large
agricultural tractor, the rear portion of which i5
schematically illustrat~d at 11. The planter 10 includes
a telescoping tongue 15 which includes~ at its forward end~
a clevis 16 for attaching to the tractor hitcho
The rear of the tongue 15 includes a bifurcated
section generally ~es;gnated 17 and which includes left and
~2~ 2
right side members 18, 19 which are spaced apart to permit
a forward, central row unit 20 to be located on the center
line of the apparatus, as will become apparent.
The rear of the bifurcated tongue section 17 is
rigidly attached to a main carrier frame 24. In the illus-
trated embodiment, the carrier frame 24 is provided with
support wheels 25, and the carrier frame 24 does not elevate
relative to its associated support wheels 25.
Supported on the carrier frame 24 is a planter
lift frame generally designated 28. The lift frame 28 of
the illustrated embodiment includes three sections: A center
section generally designated 30, and left and right wing
sections designated respectively 31 and 32. The left frame
section 31 is attached to the left side of the center frame
section 30 for vertical pivotal movement about a horizontal
axis designated 33. Similarly, the right lift frame section
32 is mounted to the right side of the center rame section
30 for pivotal motion about a horizontal axis 34.
Left and right wing lock mechanisms are included
for locking the left frame section 31 (sometimes referred
to as a "wing" or ~wing framen) and the right frame section
32 to the center frame section 30 to preclude downward motion
about the axes 33, 34 when it is desirea to raise the entire
lift frame (which includes both wings~ for transport~
Each of the lift frame sections has a forward
mounting bar and a rear mounting bar (although a single
mounting bar is possible and may ~e preferred) which are
connected together by transverse frame members to form a
rigid sec~ion frame. Thus, the left frame section 31
, 6
852
includes a forward mounting bar 36 and a rear mounting bar
37. The forward and rear mounting bars for the center frame
section 30 are designated 38 and 39 respectively; and the
corresponding forward and rear mounting bars for the right
frame section 32 are designated 40 and 41 respectively.
A set of 24 conventional planter row units desig-
nated 44 are mounted to the rear mounting bars of the frame
sections. That is, eight row units each are mounted to the
rear mounting bars 37, 39 and 41. Similarly, eight pusher-
type row units designated 45 are mounted to each of theforward mounting bars 36 and 40 of the wings, and seven
pusher row units 45, including the center row unit 20 are
mounted to the forward mounting bar 38 of the central section
30 of the lift frame. Some of the forward units have been
removed for clarity.
As best seen in the upper portion of FIG. 1~ a
plurality of storage hoppers 46 for dry fertilizer are also
mounted on the forward mounting bars 36, 38 and 40 ~although
only the two on the left side are seen in FIG. 1 f~r
clarity). Fertilizer attachments (including openers and
distribution conduits~ are provided for distributing parti-
culate fertilizer stored in the hoppers 46 when it is desired
to plant corn.
Although the invention is illustrated in the form
of a row crop planter with indiviaual row units, many aspects
of the invention are equally well suited to other large
implements, particularly winged implements, as persons
skilled in the art will readily appreciate~
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The lift frame 28 is connected to the carrier frame
24 by means of a pivot post assembly generally designated
50 in FIG. l and an hydraulically powered lift linkage
mechanism generally designated 52 and seen in more detail
in F~GS. 2-3.
The out~oard end of the left lift frame section
31 is supported by wing support wheels 54 in the plantin~
position and the intermediate raised position for end turns~ -
The outboard end of the right lift frame section 32 is
similarly supported by wing support wheels 55. Although
two wing support wheels are seen on each wing end, one, two
or three may be used, depending on the size of the planter.
The right wing frame 32 is made rigid by struts
96 welded between the forward and rear frame bars 4D, 41,
as well as by plates 97 welded between the mounting bars
at the outboard ends thereof. The for~7ard mounting bar 32
has a reduced extension 98 which is journalled on a pi~
secured at 99 in the forward mounting bar 38 of the center
frame section 30. The inboard end of the rear mounting bar
41 is secured to a transverse frame member lO0 by pivot con-
nection lOl. The left wing frame is similarly constructed
and mounted to the center frame section.
The planter system as seen in FIG. l iS set in
the planting or use configuration. The tongue 15 is
retracted to minimize the distance between the rear wheels
of ~he tractor and the planter to facilitate turns at the
end of a swath traversed by the planter. In the use position
as well as when maklng end turn~, the wing locks 35 are u~-
locked, permitting the left and right wing sections to pivo~
freely relat;ve to the CenteL frame section 30 to follo~
uneven ground contours. The entire lift frame 28, of course,
is lowered, the wing support wheels 54, 55 are actuated by
their associated hydraulic cylinders to positions between
adjacent row units and immediately adjacent those units in
the use position. The lower limit of the center frame
section 30 is determined by the lower limit of the lift
linkage assembly 52, to be described in more detail below.
Thus, each of the individual row units 44, 45 is free to
move up and down as required by the ground contour for
accurate planting depth.
The lateral spacing of the rear row units 44 is
set at the desired row spacing for corn (typically, 30 in. on
center between adjacent row units~. When corn is planted,
the forward row units 45 may be locked in a raised position,
and fertilizer from the storage hoppers 46 is distributed
adjacent each of the seed furrows when planting corn. The
forward row units 45 need not be removed from the planter
even though corn is being planted.
~ hen it is desired to plant beans, fertilizer
normally is not deposited, so the fertilizer attachments
47 are closed off and raised. The forward row units 45 are
mounted such that their center lines fall midway between
the center lines of adjacent rear row units 44.
Thus, the forward row units 45 are sometimes
referred to as "interplant~ units. If both the forward and
rear row units are employed, the resulting rows will be
planted on a 15 in. spacing.
When it is desired to raise the row units out of
ground engagement for an end turn, the lift linkage assembly
52 is actuated by a master cylinder 160 (FIGo 2) to an
intermediate height, and the left and right frame sections
31, 32 are also elevated by slave cylinders 185 relative
to their associated support wheels 54, 55 so that all of
the row units are raised above planting position and the
drive systems are disengaged. The lift linkage assembly
and its associated actuating mechanism will be further
described within, and it will then be understood that the
lift linkage assembly 52 may be raised to a height above
this intermediate position to a second height for road
transport.
When it is desired to put the planter in a trans-
port configuration, the telescoping tongue 15 is extended
and the wing locks 35 are actuated to cause the wing sections
- to be secured to the center frame section so they cann~t
rotate downward, and the lift linkage assembly 5~ is actuated
to its full height. This elevates the center frame section
30 and both wing frame sections 31, 32 as well as their
associated support wheels 54, 55 above the ground so that
the row units and wing support wheels are elevated above
the carrier frame and tongue. Next, the lift frame is
rotated counterclockwise about piVQt post assembly 50 (when
viewed from the top) approximately a quarter turn wherein
the lift frame is elongated parallel to the direction of
travel of the tractort thereby providing a minimum width
for road travel. The rotation of the lift frame about the
pivot post assembly 50 is effected by an hydraulically
powered swing linkage assembly tnot shown~; and the end of
the right frame section 32 is locked in the transport
position by a transport latch assembly mounted to 'che tongue
30 lSo
~L2~
Turning now to FIGS. 2-3, the pivot post assembly
50 and hydraulically powered lift linkage assembly 52 will
be described. The pivot post assembly 50 includes a rigid
center post 140 which is rigidly secured to the transverse
tubular frame member 80 of the carrier frame 24. The post
140 defines a ~ertical axis about which the lift frame
rotates, but the post itself does not rotate,
A sleeve or bell housing 144 is rotatably mounted
on the post 140 by means of upper and lower tapered roller
bearings to permit carrying a ve~tical load as well as tv
resis~ side thrust. The bell housing 144 is provided with
a forward bracket 147 in which three transverse pivot pins
148, 149 and 150 are mounted.
Lift linkage 52 includes left and right upper links
151, 152 which have their forward ends journalled to the
upper pivot pin 143 and their rear ends journalled on a pivot
pins 153, 154 mounted respectively to the two center struts
109 of the arched rear mounting bar of the center section
frame.
The lift linkage 52 also includes a pair of lower
links, one of which is designated 157, which have their
forward ends journalled on the lower pivot pin 149 mounted
in the bracket 147 and their rear ends journalled on a pivot
pin 158 which is mounted beneath the previously described
horizontal mounting section 111 of the arched rear mounti~g
bar.
A pair of hydraulic cylinder~, the right side
cylinder being seen and designated 160, have their butt end~
pivotally mounted OQ p;n 150 and their rcd ends journalled
on pin 163 which is m~unted in upper link 152
11
When the cylinders 160 are retracted, the lift
linkage 52 is rotated counterclockwise to the lowered
position (when viewed from the right). When the cylinders
are extended, the linkage is rotated clockwise to raise the
lift frame as seen in FIG. 2.
Each of the main lift cylinders are master
cylinders. The slave cylinders associated with master
cylinders are located to raise the left and right wing frames
31, 32 relative to the wing support tires 54. The master
cylinder on the right is seen at 160 in FIGS. 2 and 3; and
it is connected in circuit with the lift cylinders for the
right wing section.
The extension of the master cylinders is approxi-
mately twice the extension limit of the slave cylinders so
that when the slave cylinders are fully extended (thereby
raising the wings and associated row units above the ground
for an end turn), the master cylinders are extended to an
intermediate or first limit position but are not fully
extend ed .
As the master cylinders raise the center frame
section, the slave cylinders raise the outboard ends of the
wing frames at the same rate. To accomplish this, the slave
cylinders are sized relative to their associated master
cylinders such that the oil pumped from the rod end of one
of the master cylinders as it extends is fed to the butt
end of both associated slave cylinders, and causes them to
extend substantially in unison at the same rate as the master
cylinder. The force of the master cylinders and the action
of the lift linkage 52 causes the center frame section to
raise in unison with the wing sectlons~ The slave cylinders
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associated with a given master cylinder are connected in
parallel with one another. Since the hydraulic circuit for
each side (i.e., a master cylinder and its associated slave
cylinders) is the same, only the right side hydraulic lift
system need be described further.
Turning then to FIG. 4, there is shown in schematic
form the hydraulic circuit for the right side of the planter.
Reference numeral 200 designates the hydraulic pump on the
tractor, and the operator main control valve is designated
201. It includes a control lever 202 and a detent position
diagrammatically illustrated at 203. The control valve 2Ql
is a four-way or reversible selective control valve which
permits the high pressure outlet of the pump 202 to be
selectively coupled either to a first hydraulic conduit 204
or a second hydraulic conduit 205 while connecting the
complementary conduit to the pump return ~i.e., hydraulic
reservoir) for raising and lowering the lift frame. All
master and slave hydraulic cylinders are, of course, double
acting cylinders. The conduit 204 is coupled to the piston
end of the master hydraulic cylinder 160. The conduit 205
is coupled in circuit with the rod ends of the slave
hydraulic cylinders, two of which are shown and designated
respectively 185A and 185B. Althouyh t~o slave cylinders
are illustrated, the system will work equally well with one
slave cylinder or three or more slave cylinders in parallel.
The rod end of the master cylinder 160 is coupled
by means of a conduit 206 to the piston end of both slave
hydraulic cylinders. The master cylinder 160 is alsc
provided with a rephasing port 207, and the slave cylinder~
are provided with similar rephasing ports designated 208
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~ 13
and 209, respectively. All rephasing ports are located to
permit hydraulic fluid to bypass the piston when the piston
is at the fully retracted (i.e., down) position.
An auxiliary discharge conduit designated 210 has
one end coupled adjacent the rod end of slave hydraulic
cylinder 185B, but as can be seen in FIG. 5, that location
is at a position which is on the high pressure side of the
piston of the cylinder 185B when that cylinder is fully
extended. Persons skilled in the art wil`l appreciate that
the auxiliary discharge conduit 210 may be located on the
other slave cylinder 185A or in the conduit 206 or at the
rod end of the master cylinder 160, as long as it permits
hydraulic fluid to evacuate from the rod end of the master
cylinder when the master cylinder is being extended from
its first limit to its second limit position, as will be
understood from further description.
A solenoid-actuated valve ~enerally designated
212 is located in the auxiliary discharge conduit 210t the
solenoid actuator beiny diagrammatically illustrated at 213
and connected by electrical wires to a switch 214 which is
preferrably located at the operator's position on the
tractor. The discharge conduit 210 then communicates with
a conduit 215 which is the normal discharge conduit coupled
to the rod ends of the slave cylinders, and the conduits
210 and 215 are then in fluid communication with the conduit
205 connected to one of the ports of the main hydraulic
control valve 201.
The operation of the hydraulic system will now
be described. ~s seen in FIG. 4, the master and slave
cylinders are fully retracted. In this positionr the cente~
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3S2
section and the wing sections of the lift frame are lowered
so that the planter row units are in the use or planting
position. When it is desired to raise the lift frame to
the intermediate position for an end turn, the operator
actuates the control lever 202 to engage the detent 203 which
temporarily secures the control lever in that position.
Pressurized hydraulic fluid is communicated from the pump
200 to conduit 204 to extend the master cylinder 160.
Hydraulic fluid from the rod end of the master cylinder is
fed to the piston end of the slave cylinders 185A, 185B,
so that the master and slave cylinders extend in unison,
elevating the lift frame uniformly. Hydraulic fluid from
the rod ends of the slave cylinders is discharged through
conduit 215 to the return input of the pump through the
four-way main control valve 201. The solenoid-actuated valve
212 is normally closed, so no hydraulic fluid flows through
the conduit 210.
Referring now to FIG. 5, when the master cylinder
reaches a first limit position (which may be any inte~mediate
position between the fully retracted and fully extended
positions), and the slave hydraulic cylinders are fully
extended ~representing elevation of the lift frame for an
end turn~, hydraulic fluid can no longer flow from the rod
ends of the slave cylinder, nor anywhere else, so the master
cylinder also is prevented from further movement, and the
hydraulic pressure on tbe piston end of the master cylinder
increases rapidly, thereby releasing the main control valve
~01 from the detent position back to the neutral or ~off~
position. This locks the system with the master cylinder
at its first limit position, as seen in FIG. S. The farmer~
1 5
lZ,9~'B:~
of coursel can reverse the main control valve by operating
the lever to the "down" position in which the high pressure
side of pump 200 is coupled to conduit 205 and conduit 204
is connected to the return. In this case, the cylinders
all retract in unison until the planter is returned to the
planting position.
If the farmer wants to raise the lift frame to
the transport position from the intermediate position, he
actuates switch 214 to open valve 212 and places the main
control valve 201 in the "UP" position detent. When valve
212 is open and the slave cylinders are at full extension,
as seen in FIG. 6, hydraulic fluid will continue to flow
through the auxiliary discharge conduit 210 after the slave
cylinders are fully extended so that the master cylinder
can continue to extend, thereby raising the lift frame to
the transport height, at ~7hich the ~aster cylinder is in
its second limit position.
Alternatively, the system can be operated directly
from the use position to the transport position by opening
valve 212 before operating the main control valve~ This
obviates the operator's having to place the control lever
202 in the "UP~ position a second time.
It will also be appreciated that the main valve
need not necessarily have a detent t yet the system will
prevent inadvertent placement of the lift frame in the
transport position. If the detent feature o th~ main
control valve were eliminated~ the operator would hold the
lever in the ~up~ position. When the slave cylinders were
fully extended, the hydraulic pu~p woula increase pressure
16
s;~
and this would result in an audible signal which the farmer
could detect, and release the control lever, which ~ould
be returned to the neutral position by a spring. The master
cylinder could not be further extended until the solenoid
valve 214 is opened (which could~ of course, be at the
beginning of a cycle if the farmer wanted to place the lift
frame directly in the transport position from the use
position).
Having thus disclosed in detail one embodiment
of the invention, persons skilled in the art will appreciate
that the invention is not limited to the planter shown and
that equivalent elements can be substit~ted for those
disclosed while continuing to practice the principle of the
invention~ It is therefore intended to cover all modifi-
cations, applications and substitutions includc-d in the
- appended claims.
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