A tri-fold row marker comprises three arm segments, a winglet pivotally coupled to the toolbar, an inner arm pivotally coupled to the winglet, and an outer arm pivotally coupled to the inner arm. A marker disc is mounted to the distal end of the outer arm for marking the ground surface when said row marker is its extended working position. The winglet is provided with a first bell crank extending upwardly from the winglet and a second bell crank extending downwardly from the winglet. The inner arm is provided with a third bell crank extending downwardly therefrom. A double acting hydraulic cylinder is pivotally coupled to the agricultural implement and the first bell crank for retracting and extending the row marker. An inner control arm is pivotally coupled to the agricultural implement and the third bell crank for pivoting the inner arm relative to the winglet when the hydraulic cylinder is extended or retracted. An outer control arm is pivotally coupled to the second bell crank. The outer control arm is also coupled to the inner and outer arms by two pivot links that are pivotally coupled to the outer control arm and the inner and outer arms. The outer control arm pivots the outer arm relative to the inner arm when the hydraulic cylinder is extended or retracted. Retracting the hydraulic cylinder from its extended position folds the marker arm into its retracted transport position, and extending the hydraulic cylinder from its retracted position unfolds the marker arm into its extended working position.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention is directed to a tri-fold row marker having three sections 
that are pivotally coupled to one another. The row marker has an extended 
working position and a retracted transport position. 
2. Description of the Prior Art 
Row markers are commonly attached to agricultural implements, such as 
planters and grain drills, to mark the field for the farmer's next pass. 
As implements have become wider row markers have become longer. The longer 
row markers have folded transport positions and extended working 
positions. 
Bi-fold row markers have two pivot points, see U.S. Pat. No. 4,530,405. In 
the patent identified above, the bi-fold marker has an inner arm that is 
pivotally mounted to the planter toolbar and an outer arm that is 
pivotally coupled to the inner arm. A hydraulic cylinder manipulates the 
inner arm into and out of its horizontal working position and vertical 
transport position. The outer arm is extended by a cable that is coupled 
between the outer arm and the toolbar. As the hydraulic cylinder pivots 
the inner arm from its vertical transport position to its horizontal 
working position, the cable extends the outer arm so that it is in line 
with the inner arm when the row marker is in its working position. 
As agricultural implements became wider tri-fold markers were developed 
having three pivot points, see U.S. Pat. Nos. 4,207,950, 4,449,590 and 
4,986,367. In all three above-identified tri-fold designs, a single 
hydraulic cylinder is used to manipulate the folding and unfolding action 
of the row marker. In the first two designs, U.S. Pat. Nos. 4,207,950 and 
4,449,590, a cable or chain is used to extend the outer arm during an 
unfolding operation in a manner similar to the above discussed bi-fold row 
marker. The cable or chain does not control the movement of the outer arm 
during the folding cycle, creating a high kinetic impact when the outer 
arm engages a stop located on the inner arm. In the third design, U.S. 
Pat. No. 4,986,367, a control arm is used to extend the outer arm. 
SUMMARY 
It is one of the objects of the present invention to provide a row marker 
that simultaneously folds the arm segments in a quick and smooth folding 
motion, reducing accelerations and kinetic impact caused by a change in 
the direction of travel and center of rotation. 
It is a feature of the present invention that the outer control arm is 
located below the outer and inner arms when the row marker is in its 
extended working position, thereby minimizing the maximum height of the 
row marker during the fold cycle. 
It is another feature of the present invention that the marker itself moves 
vertically into and away from the ground rather than sliding horizontally 
along the ground as it is being extended and retracted. 
It is another object of the present invention that the hydraulic cylinder 
that extends and retracts the row marker is located and operated to 
minimize its exposure to the environment. 
It is another feature of the present invention that the hydraulic cylinder 
is located above the winglet away from the dirt when the marker arm is in 
its extended working position, and is protected by being folded inside the 
arm when the marker arm is in its retracted transport position. 
It is another feature of the present invention that the hydraulic cylinder 
is retracted when the row marker is in its retracted transport position, 
thereby protecting the cylinder rod from damaging weather during extended 
periods of storage. 
The present invention comprises a tri-fold row marker for an agricultural 
implement. The row marker comprises three sections, a winglet pivotally 
coupled to the toolbar, an inner arm pivotally coupled to the winglet, and 
an outer arm pivotally coupled to the inner arm. A surface marking means 
comprising a marker disc is mounted to the distal end of the outer arm for 
marking the ground surface when said row marker is its extended working 
position. 
The winglet is provided with a first bell crank extending upwardly from the 
winglet and a second bell crank extending downwardly from the winglet. The 
inner arm is provided with a third bell crank extending downwardly 
therefrom. A hydraulic cylinder is pivotally coupled to the agricultural 
implement and the first bell crank for retracting and extending the row 
marker. An inner control arm is pivotally coupled to the agricultural 
implement and the third bell crank for pivoting the inner arm relative to 
the winglet when the hydraulic cylinder is extended or retracted. An outer 
control arm is pivotally coupled to the second bell crank. The outer 
control arm is also coupled to the inner and outer arms by two pivot links 
that are pivotally coupled to the outer control arm and the inner and 
outer arms. The outer control arm pivots the outer arm relative to the 
inner arm when the hydraulic cylinder is extended or retracted. Retracting 
the hydraulic cylinder from its extended position folds the marker arm 
into its retracted transport position, and extending the hydraulic 
cylinder from its retracted position unfolds the marker arm into its 
extended working position. 
The inner control arm is pivotally coupled to the toolbar by a float slot. 
The hydraulic cylinder is pivotally coupled to the toolbar by a spring 
biassed toggle link. The float slot and toggle link allow the row marker 
to float up and down with the contours of the ground to a limited degree. 
In its extended working position the outer arm is kept rigid with the 
inner arm by an outer stop positioned between the inner arm and outer arm. 
The upward force of the marker disc pushes the outer arm upwardly so that 
the outer stop locks against the inner arm. The upper motion of the marker 
disc is transmitted through the outer control arm to lock the inner arm 
against the winglet.

DETAILED DESCRIPTION 
Tri-fold row marker 10 of the present invention is mounted to the end of 
toolbar 12. The toolbar is provided with a number of planting units 13. It 
should be noted the toolbar carry a variety of agricultural implements, 
such as a grain drill or a sprayer unit. 
The row marker comprises three arm segments, a winglet 14, an inner arm 16 
and an outer arm 17. The winglet 14 has a first end 18 and a second end 
20. The first end is pivotally coupled to the toolbar 12 by a winglet 
mounting bracket 24, best illustrated in FIGS. 4 and 5. The inner arm 16 
has a first end 26 and a second end 28. The first end 26 of the inner arm 
16 is pivotally coupled to the second end 20 of winglet 14 at 29. 
Similarly the outer arm 17 has a first end 30 and a second end 32. The 
first end 30 of the outer arm 17 is pivotally coupled to the second end 28 
of the inner arm 16 at 33. The second end 32 is provided with a surface 
marking means comprising a marker disc 35 that is rotatably mounted to the 
outer arm. 
It should be noted that the second end 32 of the outer arm 17 would be 
provided with an extension tube to which the marker disc 35 would be 
secured. The extension tube allows the operator to make minor length 
adjustments for different sized machines and to satisfy personal 
preferences as to marker location. 
The winglet 14 is provided with a first bell crank 34 and a second bell 
crank 36. The cylinder portion 38 of a double acting hydraulic cylinder 40 
is pivotally coupled to the toolbar by a toggle link 42. The piston rod 
end 44 of the hydraulic cylinder is pivotally coupled to the first bell 
crank 34. By extending or retracting the hydraulic cylinder the winglet is 
pivoted relative to the toolbar. The toggle link is biassed outwardly from 
the toolbar by torsion spring 43. The hydraulic cylinder 40 is best 
illustrated in FIGS. 4 and 5, only its location is identified in FIGS. 2 
and 3 for clarity. 
The torsion spring 43 biases the toggle link outwardly from the toolbar so 
that the toggle link is in its outboard position, illustrated in FIG. 5, 
when the row marker is fully retracted. The spring does not overcome the 
force of the hydraulic cylinder, however as the row marker is folded from 
its extended working position to its retracted transport position, the 
cylinder and the toggle link move from tension to compression members (the 
center of gravity of the marker goes over center). During this switchover 
the spring rotates the toggle link away from the toolbar into its outboard 
position for the remainder of the fold cycle. With the toggle link in this 
outboard position assured by the torsion spring, a smoother unfolded 
motion is achieved when the row marker is unfolded from its retracted 
transport position to its extended working position. 
The first end 26 of the inner arm 16 is provided with a third bell crank 
46. An inner control arm 48 is provided with a first end 50 having a pivot 
pin 51. The first end 50 is pivotally coupled to the toolbar by a float 
slot 52. The inner control arm 48 is provided with a second end 54 that is 
pivotally coupled to the third bell crank 46 at 56. The inner control arm 
48 pivots the inner arm relative to the winglet when the hydraulic 
cylinder is extended or retracted and the inner control arm has reached 
the limit of the float range defined by the float slot. 
Two pivot links 58 and 60 have first ends 62 and 64 that are pivotally 
coupled to the outer and inner arms 16 and 17, respectively. The pivot 
links 58 and 60 are also provided with second ends 66 and 68. An outer 
control arm 70 is provided with a first end 72 that is pivotally coupled 
to the second bell crank at 74, and a second end 76 that is pivotally 
coupled to the second ends 66 and 68 of pivot links 58 and 60 at 78. The 
outer control arm 70 pivots the outer arm relative to the inner arm when 
the hydraulic cylinder is extended or retracted. 
In its extended working position the row marker is allowed to float up and 
down to a limited degree so that the marker disc may follow the ground 
undulations. As shown in FIG. 2, position A marks the lowermost float 
position and position B marks the uppermost float position. Typically the 
row marker is positioned between these two extremes. The float range is 
dictated by the float slot and the toggle link. As the row marker floats 
up and down these two couplings allow for a range of lost motion in the 
system. 
The inner and outer arms are locked in a rigid extended configuration by 
the outer stop 80. The outer stop comprises two plates that are welded to 
the inner and outer arms. Only outer arm stop plate 82 is shown in FIG. 3 
as the stop plates are hidden by the flange forming the pivot 33. In its 
extended working position, the marker disc of the row marker contacts the 
ground forcing the outer arm upwardly. This upward force rotates the upper 
arm about pivot 68 forcing the outer arm plate against the inner arm 
plate. 
The winglet is provided with inner stop 86. The inner stop comprises a 
plate that is welded to the winglet and extends therefrom so as to contact 
the topside of the third bell crank 46 when the winglet and the inner arm 
are axially aligned. The upward force of the ground against the marker 
disc drives the outer control arm to lock the inner arm against the inner 
stop 86. 
When the row marker is retracted from its extended working position to its 
retracted transport position, the row marker stays in its rigid 
configuration until the upper float range is exceeded. After the upper 
limit of the float range has been exceeded, the inner arm is rotated 
relative to the winglet by the inner control arm, and the outer arm is 
rotated relative to the inner arm by the outer control arm, see position C 
in FIG. 3. These simultaneous movements continue until the row marker is 
in its fully retracted transport position, see position D in FIG. 3. 
The winglet mounting bracket 24 is best illustrated in FIGS. 4 and 5. The 
mounting bracket to pinned to the toolbar by vertical pin 90. A horizontal 
bolt axially aligned with the toolbar further secures the mounting bracket 
to the toolbar. The horizontal bolt couples a toolbar ear to a mounting 
bracket ear. The horizontal bolt and the associated mounting ears are not 
shown, as they are on the other side of the mounting bracket. At a 
selected design tension, the horizontal bolt fails thereby providing 
breakaway protection for the marker. 
The bracket is provided with horizontal pivot pin 92 that pivotally couples 
the winglet 14 to the bracket. The mounting bracket is also provided with 
vertically upstanding plate 96 in which float slot 52 is formed. The first 
end 50 of the inner control arm 48 is provided with a yoke which 
sandwiches the upstanding plate 96 therebetween. Float pivot pin is 
mounted to the yoke and passes through the float slot 52. 
The base end of cylinder portion 38 of the hydraulic cylinder 40 is also 
provided with a yoke that sandwiches the toggle link 42 therebetween. 
Pivot pin 98 secures the toggle link to the hydraulic cylinder. The other 
end of the toggle link is pivotally coupled between two ears formed in the 
mounting bracket and pivotally secured thereto by pivot pin 100. A curved 
toggle link stop member 102 is located between the two ears. This stop 
member is designed to stop the rotation of the toggle link when the float 
pin 51 reaches the end of the float slot 52, as illustrated in FIGS. 4 and 
5. 
The tri-fold row marker of the present invention should not be limited by 
the above-described embodiments, but should be limited solely by the 
claims that follow.