Note: Descriptions are shown in the official language in which they were submitted.
CA 02776759 2012-05-02
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OFFSET HITCH FOR MOWING MACHINE
This invention relates to a pull-type rotary mower with an offset, floating
hitch. The offset,
floating hitch allows the tractor to be outside of the mowing area, within the
mower cutting
width, or anywhere in between these two tractor positions. In addition, the
offset, floating
hitch allows more than one rotary mower to be towed behind one tractor.
BACKGROUND OF THE INVENTION
Rotary mowers, disc mowers and rotary cutters are typically towed by a tractor
and are
used for mowing highway rights-of-way. Often ditches are quite steep and it is
dangerous
to have the tractor operate on the steep side-slope of a ditch. Recently,
offset hitches have
been developed where a standard, centerline-hitch mower is attached to the
rear of one
side of an offset hitch and a tractor is attached to the front of the other
side of the offset
hitch. The offset hitches are often supported with two wheels and the hitches
typically
have a combination of gearboxes, regular u-joints, and constant-velocity u-
joints to
transmit power from the tractor to the mower gearboxes. Other variations of
mower hitches
are available but they are complex and costly due to the addition of numerous
gearboxes
and other driveline components.
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With current mowers, only one pull-type mower is typically pulled behind one
tractor. When
mowing a wide highway right-of-way, this involves significant labor costs for
the mowing
operation. It would be advantageous to be able to have a wider mowing width,
while still
accurately following the ground by using narrow sections within the mowers.
SUMMARY OF THE INVENTION
This rotary mower is a mower with an offset, floating hitch that allows mowing
in the ditch
adjacent to the road while permitting the tractor to operate up on the road
surface. The
offset, floating hitch of the rotary mower also allows mowing with the tractor
ahead of, and
within the mower cutting width. In addition, the offset, floating hitch can be
rotated through
the whole range of motion while mowing under full power. The offset, floating
hitch is
simple and eliminates the need for any additional costly constant-velocity
universal joints
and gearboxes. When using the offset, floating hitch, at least one caster
wheel is used to
support the front of the rotary mower. Because the front of the rotary mower
is supported
in this way, the offset, floating hitch may be mounted on either side of the
mower. This
allows assembly of the mower and hitch so that the operator can either drive
"with" the
traffic or "against" the traffic. In addition, two or more rotary mowers
equipped with the
offset, floating hitch can be pulled behind one tractor.
With these and other advantages, as will become apparent to those skilled in
the art, the
invention is herein described by reference to the accompanying drawings, which
includes a
description of the best mode known to the applicant and of the preferred
typical
embodiment of the principles of the present invention.
DESCRIPTION OF THE DRAWINGS
Fig. 1 is a top view of a rotary mower assembled with the offset, floating
hitch on the left
side of the mower, and with the tractor located outside of the mower cutting
width.
Fig. 2 is a top view of a rotary mower assembled with the offset, floating
hitch on the left
side of the mower, and with the tractor located within the mower cutting
width.
Fig. 3 is a top view of a rotary mower assembled with the offset, floating
hitch on the left
side of the mower, showing the mower and tractor in transport position.
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Fig. 4 is a top view of a rotary mower assembled with the offset, floating
hitch on the right
side of the mower, and with the tractor located outside of the mower cutting
width.
Fig. 5 is a top view of a rotary mower assembled with the offset, floating
hitch on the right
side of the mower, and with the tractor within the mower cutting width
Fig. 6 is a top view of a rotary mower assembled with the offset, floating
hitch on the right
side of the mower, showing the mower and tractor in transport position.
Fig. 7 is a top view of two rotary mowers towed behind one tractor, in mowing
position.
Fig. 8 is a top view of two rotary mowers towed behind one tractor, in
transport position.
DETAILED DESCRIPTION OF THE INVENTION
Pull-type rotary mowers are used for mowing ditches throughout the world. Many
of these
mowing conditions in the ditches are hazardous to the operator of the tractor
due to
extreme side-slopes and rough terrain. In addition, broken bottles and other
sharp litter in
the ditches are harmful to the tractor tires. It is therefore advantageous to
utilize a rotary
mower with a hitch that allows the tractor to operate on the road surface
while the mower
is engaging the hazardous ditch adjacent to the roadway. In some other
situations, the
tractor must be operated within the mowing width, so it is a benefit to be
able to shift the
tractor position relative to the mower, so that the tractor can easily be set
to mow outside
the mower cutting width or within the mower cutting width. In addition, the
tractor should be
positioned to provide a narrow transport width, for safe transport on a
highway.
A particularly advantageous embodiment of the invention is illustrated in two
different
operating positions in Figure1 and Figure 2, as well as a transport position
in Figure 3. The
offset, floating hitch assembly 1 is pivotally attached to the front of a pull-
type mower
assembly 2 about a horizontal pivot axis 3 that is approximately perpendicular
to the
forward motion of the mower. Horizontal pivot axis 3 is located to the front
of mower 2 and
off to one side of mower 2. At least one caster wheel 4 supports the front of
the pull-type
mower 2. The front of the offset, floating hitch assembly is typically
attached to an
agricultural tractor which does not form part of the invention.
Offset, floating hitch assembly 1 comprises a hitch beam 5 and a rotary link
6. Said hitch
beam 5 is pivotally attached to said rotary link 6 about a vertical axis 7.
Hydraulic actuator
8 is pivotally attached to hitch beam 5 and also pivotally attached to rotary
link 6 to provide
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power for rotation of hitch beam 5 relative to rotary link 6 about vertical
axis 7. Figure 1
shows one position of hitch beam 5 relative to rotary link 6 and Figure 2
shows a different
position of hitch beam 5 relative to rotary link 6. Movement between these
positions is
provided by hydraulic actuator 8.
An embodiment of pull-type mower assembly 2 comprises center section 9 and
bolt-on
frame extension 10. By providing a bolt-on frame extension 10, the pull-type
mower
assembly 2 can be assembled so that offset, floating hitch assembly 1 is
either to the front,
right of center section 9 or to the front, left of center section 9. This
allows the tractor
operator to either drive in the same direction as the traffic or in a
direction opposite (facing)
the traffic, depending on personal preference and the laws in place where the
mower is in
use.
Figure 4 shows a rotary mower assembled with the offset, floating hitch
assembly 1 on the
right side of the mower, and with the tractor located outside of the mower
cutting width.
Figure 5 shows this assembly with tractor inside of the mower cutting width,
and Figure 6
shows this assembly with the rotary mower in transport position.
Power driveline 11 transmits power from the agricultural tractor to a multi-
mount gearbox
12 located on center section 9 of the mower assembly 2. Power driveline 11 is
supported
by offset, floating hitch 1 and frame extension 10. Power driveline 11 is a
simple, in-line
driveline with universal joints, and not requiring gearboxes. In Figure 1,
multi-mount gear
box 12 is shown with thru-shaft oriented from front-left to rear-right,
facilitating power
arriving from the front-left of the center section 9. Figure 4 shows multi-
mount gearbox 12
rotated 180 degrees about a horizontal axis in the direction of travel. In
Figure 4, multi-
mount gear box 12 is shown with thru-shaft oriented from front-right to rear-
left, facilitating
power arriving from the front-right of the center section 9. Thus, with
properly designed
components: hitch beam 5, rotary link 6, frame extension 10, power driveline
11, and multi-
mount gearbox 12, the rotary mower may be marketed as a unit that can have the
tractor
operating either on the left side of the rotary mower or the right side of the
rotary mower.
Determining the tractor location is accomplished by assembling the components
in the
desired orientation.
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In some markets, for simplicity, it may be advantageous to weld center section
9 to frame
extension 10. .
Figure 7 and Figure 8 illustrate two rotary mowers being pulled behind one
tractor, in
mowing position and transport position, respectively. The offset, floating
hitch assembly 1
of the rear rotary mower is pivotally attached to a rear hitch 13 of the front
rotary mower.
The offset, floating hitch assembly 1 of the rear rotary mower is pivoted
using hydraulic
actuator 8. This allows the rear rotary mower to be offset adequately, for
operation in the
cutting position, relative to the front rotary mower. It also allows the rear
rotary mower to
be moved toward the centerline of the front rotary mower for clearing
obstacles and for
transport position as shown in Figure 8.
