Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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FOLDING HAY RAKE
FIELD OF THE INVENTION
The present invention relates to agricultural implements and has
particular relation to a folding mechanism for an agricultural implement.
BACKGROUND
Certain agricultural implements have a primary frame and folding
secondary frames. These include, for example, wheel rakes for gathering cut
forage
into a windrow. The windrowed crop can then be baled or harvested in some
other
way. With the development of high capacity balers, it is beneficial to be able
to gather
two or more swaths or windrows into one windrow in order to save baling time.
The
use of wide rakes reduces the time required to both rake and bale a field.
The construction of wide rakes requires a convenient mechanism for
folding the rakes for transportation.
The folding mechanisms proposed in the past include the use of two
double-acting cylinders directly connecting the main frame with the secondary
rake
wheel mounting frames as disclosed in Menichetti United States patent
5,685,135.
Another known system uses two stretcher arms pivotally connected to the rake
wheel
mounting frames and to a common slide mounted on the main frame, with a single
cylinder for moving the slide. A system of this sort is disclosed in Peeters
United
States patent 5,598,691.
These known prior art systems suffer from certain disadvantages. With
a double cylinder arrangement, the cylinders are long and expensive and an
additional mechanism must be provided to ensure that the cylinders extend and
retract uniformly and maintain uniform positions. In this system, the
cylinders are
used as structural components in tension when the rake is in the open, field
position.
If the rake is to be used at a partially opened position, cylinder creep can
be expected.
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With the single cylinder and slide arrangement, the cylinder is shorter
but still relatively long. In use it is under compression so that In a
partially open
position, cylinder creep can be expected.
The present invention aims at the provision of novel features in a folding
implement of this type.
SUMMARY
According to the present invention there is provided an agricultural
implement comprising:
an elongate main frame with a leading end and trailing end;
two secondary frames pivotally mounted on opposite sides of the main
frame for pivotal movement of each secondary frame between a transport
position
extending along a respective side of the main frame and a field position
diverging
from the respective side of the main frame in a direction from the trailing
end to the
leading end;
a folding mechanism for moving the secondary frames between their
transport and field positions, the folding mechanism comprising:
two fold arms;
fixed pivot means pivotally mounting the two fold arms on the
main frame;
two connection braces pivotally connected to the respective
secondary frames;
brace pivots pivotally connecting the connection braces to
respective ones of the fold arms at positions spaced from the fixed pivot
means; and
fold actuating means for pivoting the fold arms about the fixed
pivot means for moving the secondary frames between the transport and the
field
positions.
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Each fold arm acts as a lever turning on the fixed pivot connection to the
main frame. In the position of maximum secondary frame divergence, the pivot
points
for the fold arm and the connection brace are aligned, and no moment is
applied to
the fold arm from drag forces on the secondary frame. This means that the fold
actuator is not a primary structural member taking large loads in the field
position.
Even in a partially open condition, the loads are quite small, mitigating the
potential for
cylinder creep where the actuator is an hydraulic cylinder. Appropriate
selection of
the fold arm geometry limits the necessary travel of the actuator, so that a
relatively
short stroke cylinder can be used.
In a preferred embodiment of the present invention, the fold actuating
means include a slide mounted on the main frame of the implement and links
connecting the slide to the fold arms between the fixed pivot means and the
braces.
The fold actuating means also preferably include an hydraulic cylinder mounted
on
the main frame for moving the slide along the main frame. The implement can be
used with only one of the secondary frames deployed by disconnecting one of
the
links from the slide. The disconnected link may be connected to the main
frame.
In preferred embodiments of the implement, the main frame has an
elongate main beam and a cross beam at the trailing end of the main beam. The
secondary frames are pivotally mounted on the cross beam on opposite sides of
the
tongue. The cross member is supported on ground wheels and has an adjustable
length to adjust the overall width of the implement between the secondary
frames.
The implementation of these characteristics and other preferred or
optional features will be described in the following in connection with an
exemplary
embodiment of a rake. It is to be understood that other embodiments, including
other
types of implement are possible.
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BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate an exemplary
embodiment of the present invention:
Figure 1 is an isometric view of a rake in a deployed, field position;
Figure 2 is an isometric view of the rake of Figure 1 in a transport
position;
Figure 3 is an isometric view of the rake with only one side deployed;
Figure 4 is a plan view of the rake in the field position;
Figure 5 is a plan view of the rake in the transport position;
Figure 6 is a plan view of the rake with one rake arm deployed;
Figure 7 is a side elevation of the rake in the transport position;
Figure 8 is a trailing end elevation of the rake in the transport position;
Figure 9 is an isometric detail of the folding mechanism;
Figure 10 is a plan view of the folding mechanism;
Figure 11 is an isometric like Figure 9 showing one side of the folding
mechanism deployed and the other disconnected;
Figure 12 is a plan view of the folding mechanism with one side
deployed and the other disconnected;
Figure 13 is a trailing end elevation of the implement partially broken
away to show the width adjustment mechanism; and
Figure 14 is an isometric detail of the rake wheel raising and lowering
mechanism.
DETAILED DESCRIPTION
Referring to the accompanying drawings, there is illustrated an
agricultural implement in the form of a wheel rake 10 with a T-shaped main
frame 12.
At the leading end of the main frame is a hitch pole 14 carrying a clevis type
hitch 16
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and a support jack 18. The hitch pole 14 projects forwardly from the main beam
20 of
the frame 12.
The main beam 20 extends longitudinally of the implement to a trailing
end where it is connected to a cross beam 22. An upright leg 24 at each end of
the
cross beam carries a ground wheel 26. Two secondary frames in the form of rake
arms 28 are mounted on the respective legs 24 by double axis joints 30 that
allow the
rake arms 28 to pivot laterally between the deployed state illustrated in
Figure 1 and
the transport position illustrated in Figure 2 and also vertically to
accommodate
variations in ground level. So that each rake arm may follow the ground
contours, it is
equipped with a caster wheel 32 partway along the arm.
Each rake arm is equipped with six rake wheels 34. The mounting of
these wheels will be described in more detail in the following.
To effect the movement of the rake arms 28 between the deployed, field
position illustrated in Figure 1 and the transport position illustrated in
Figure 2, the
rake implement is provided with a fold mechanism 36 that is illustrated most
particularly in Figures 9 through 12. The fold mechanism includes two fold
arms 40
mounted on the main beam 20 of the main frame by a fixed pivot 42. The inner
section 44 of each fold arm is bifurcated to extend across the top and bottom
of the
main beam for connection to the pivot. The outer section 46 of the fold arm
projects
from the outer end of the inner section at an obtuse angle. At its outer end
each fold
arm it carries a pivot connection 48.
Between the fixed pivot 42 and the pivot connection 48 is an
intermediate pivot 50 connected to a fold link 52. The link 52 extends from
the fold
arm to a slide 54 that is mounted slidably on the main beam 20 of the main
frame
between the fixed pivot 42 and the leading end of the main frame. The slide is
composed of two side channels 56 on opposite sides of the main beam, a top
plate 58
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and a bottom plate 60 respectively above and below the main beam. The top and
bottom plates 58 and 60 are trapezoidal and project beyond the main beam to
provide
ears through which holding pins 62 may be inserted to couple the ends of the
fold
links 52 to the slide. On the top of the slide are two lugs 64 that are used
to provide a
coupling to the piston rod 66 of an hydraulic fold cylinder 68. The cylinder
extends
along the main beam 20 and is connected to a cylinder mounting bracket 70
between
the slide and the fixed pivot 42.
The pivot connections 48 on the ends of the fold arms 40 are connected
to braces 71 that extend from the fold arms to brace mounts 72 (Figures 1, 4
and 7)
mounted on respective ones of the rake arms 28 to which they are connected by
pivot
connections 73. The brace mounts project upwardly and towards the trailing end
from
the respective rake arms to clear the rake wheels in a raised, transport
position of the
wheels.
To unfold the rake frame from the transport position (Figures 2 and 5) to
the field position (Figures 1 and 4), the fold cylinder 68 is actuated to push
the slide
54 forwardly along the main beam 20. This pulls on the fold links 52, rotating
the fold
arms 40 about the fixed pivot 42. This pushes the inner ends of the braces 71
outwardly and forwardly, forcing the rake arms 28 outwardly to the field
position. As
can be seen most readily from Figure 4, in the position of maximum extension
of the
rake arms, the fixed pivot 42, the pivot connection 48 and the pivot
connection 73
between the brace and the brace mount are aligned so that any forces acting on
the
rake arm and through the brace will have a line of action through the fixed
pivot or
very close to it. Consequently, no moment is applied to the fold arm and there
is no
tension on the fold link and no compressive force on the fold cylinder. In
practice, the
alignment may not be perfect but the forces transmitted to the cylinder are
minimal
and the danger of cylinder creep is likewise minimized. Where the rake is only
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partially deployed, larger forces will be exerted on the cylinder, but these
are again
limited by the geometry of the fold mechanism.
The rake can be used with only one side deployed as illustrated in
Figures 3 and 6. The disposition of the fold mechanism to achieve this is
illustrated in
Figures 11 and 12. The folding pin 62 for the side of the implement that is to
remain
folded is disconnected from the slide 54. This frees the associated link 52
from the
slide so that when the cylinder is extended, only the other side of the
implement will
be unfolded to the field position. A fold arm retainer 74 mounted on the main
beam
behind the fixed pivot 42 carries a pair of lock pins 76, one on each side.
When one
side is to be disconnected, the lock pin is passed through lock apertures in
the
retainer and through a fold arm lock sleeve 78 (Figures 9 and 10) mounted on
the
outer end of the lock sleeve and which aligns with the lock holes in the
retainer in the
folded condition of the fold arm.
A link guide bracket 80 is mounted on the main beam. It extends
laterally to both sides of the main beam under the fold links 52. It has
apertures 82
that, in the folded condition of the implement shown in Figure 5, are beside
the folding
pins 62 connecting the slide and the fold links. A disconnected fold link can
then be
swung outwardly and pinned to the guide bracket 80 using the link pin 62.
This, along
with the fold arm retainer and lock pin 74 and 76, secures the non-active side
of the
rake against inadvertent unfolding.
At the leading end of the main frame are two transport locks 84. These
are connected to the main beam 20 by joints that pivot about a horizontal axis
transverse to the main beam and a perpendicular second axis. The transport
locks
extend from the main beam to the front ends of the rake arms in the transport
position
where the locks are connected to studs on the rake arms. In the field
position, the
transport locks are rotated and pivoted to positions extending along the main
beam
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and held in place using brackets 92 on the main beam and pins 94.
As illustrated most particularly in Figure 13, the cross beam 22 of the
main frame is a composite beam with an outer tube 96 connected across the end
of
the main beam 20 and two inner tubes 98 engaged telescopically in the ends of
the
outer tube. The inner tubes carry the legs 24. At the center of the outer tube
96 is a
vertical cross plate 100 carrying two nuts 102. Threaded into these nuts are
two
crank rods 104, which extend to opposite ends of the cross beam, where each is
supported in a bracket 106. Two collars 108 pinned to the crank rod prevent
relative
movement of the inner tube along the crank rod. A crank 110 is mounted on the
outer
end of each crank rod. At the ends of the outer tube 96 are clamps 112 that
serve to
clamp the respective inner tubes 98 in place with respect to the outer tube.
This mechanism may be used for adjusting the length of the cross beam
and therefore the width of the rake. The clamps 112 may be released and the
cranks
110 operated to move the inner tubes 98 in and out of the outer tube to a
desired
adjusted width and then the clamps are re-engaged.
Figure 14 illustrates the rake wheel mounting and lifting mechanism.
For each rake wheel 34 there is a rake wheel arm 114 that carries a transverse
shaft
116 at the leading end. The shaft is engaged in a sleeve 118 mounted on the
underside of the rake arm. At the opposite, trailing end of the arm 114 is a
hub 120
for mounting the respective rake wheel.
An arm 122 projects upwardly from each rake wheel arm 114. This is
connected to a spring 124 and to a chain 126 that extend from the arm, in
parallel with
the spring, to limit the spring extension. The chain goes beyond the spring to
a collar
128 mounted on a control rod 130 extending along the rake arm. The control rod
is
supported on the rake arm by a series of control rod brackets 132. The rear
end of
the control rod 130 carries a stroke control bolt 134 that may be adjusted
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longitudinally with respect to the control rod. The stroke control bolt
confronts a stop
brake 136 on the rake arm to limit the travel of the control rod towards the
trailing end
of the rake arm.
Longitudinal movement of the control rod is caused by a double acting
lift cylinder 140 mounted on the rake arm by a cylinder mounting bracket 142.
The
piston rod of this cylinder is connected to a bracket 144 on the control rod.
When
extended, the cylinder moves the control rod towards the trailing end of the
rake arm
and lowers the rake wheels to the extent permitted by the engagement of the
stroke
control bolt with the bracket 136. The opposite movement of the cylinder draws
the
control rod to the leading end and raises the rake wheels off the ground for
transport
purposes.
The use of a double acting cylinder in the wheel lifting mechanism
provides a positive positioning of the rake control rod. With a single acting
cylinder
and a spring return, significant delays and sluggish movement can be
experienced
when lowering the wheels to their working positions
While one embodiment of the present invention has been described in
the foregoing, it is to be understood that other embodiments are possible
within the
scope of the invention. For example, the single cylinder and slide arrangement
can be
replaced with two cylinders acting directly on the fold arms. With this
arrangement,
each side of the rake could be moved independently of the other when connected
to
separate hydraulic circuits on the tractor. Some advantages may be gained with
this
arrangement under some field conditions. If the two cylinder arrangement is to
be
used with a single hydraulic circuit, some means would be required to ensure
that the
two sides open uniformly. This could be done either mechanically or
hydraulically.
In view of the numerous changes and modifications that could be made
within the scope of the invention, the invention is not to be considered
limited by the
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foregoing description, but solely by the scope of the appended claims.
