Note: Descriptions are shown in the official language in which they were submitted.
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_ _. _...._~ ~_..__...~_ _..... --'~ 02417428 2003-O1-20 ~~ ,. --~--~ _
OFFSET HITCH FOR MOWING MACHINE
The invention relates to a towed mower with a walking-caster-hitch. The
walking-caster-
hitch allows the tractor to he outside of the mowing area, on centerline with
the mowing
area or anywhere in between these two tractor positions. In addition, the
walking-caster-
hitch allows more than one swing mower to be towed behind one tractor.
BACKGROUND OF THE tNVENTtON
Rotary mowers, disc mowers and flail mowers are available as pull-type mowers.
These
mowers are typically used for cutting highway rights-of way and for cutting
hay for
livestock. Often the ditches are quite steep and it is dangerous to have the
tractor operate
on the steep side slope of the ditch. With existing mowers, the tractor is
typically attached
to the front of the mower and on the centerline of the mower. This often
requires operating
the tractor on the steep side slopes of the ditch.
Recently, offset hitches have been developed where a standard, centerline
hitch mower is
attached to the rear of one side of the offset hitch and a tractor is attached
to the front of
the other side of the offset hitch. The offset hitches are typically supported
with two
wheels. The hitches typica!!y have a combination of gearboxes and constant-
velocity ~!-
joints to transmit the power-take-off power. In addition, when the offsef
hitch is utilized, the
CA 02417428 2003-O1-20
tractor must operate off to the side of the mower and the mower cannot be
operated with
the tractor on the centerline of the mower.
U'Jith current technology, the operator is required to maneuver around
obstacles. This Bray
result in the mower leaving an unnecessary amount of uncut grass around the
obstacle or
it may mean that the obstacle is struck by the mower resulting in damage to
the obstacle,
the mower or both.
~nly one pull-type mower is typically pulled behind one tractor. This involves
significant
labor costs for the mowing operation.
5~111~MAFtY OF THE 1NVENTIt~N
The swing mower is a mower with a walking-caster-hitch that allows mowing in
the ditch
adjacent to the road while leaving the tractor to operate up an the road
surface. The
walking-caster-hitch of the swing mower also allows mowing with the tractor
directly ahead
of the centerline of the mower. In addition, the walking-caster-hitch can be
rotated through
the whole range of motion while mowing under full power. The walking-caster-
hitch is
simple and eliminates the need for any additional costly constant-velocity
universal joints
and gearboxes. The swing mower may be equipped with a sensor out in front of
the mower
to sense obstacles such as sign posts and then swing the hitch so that the
mower clears
the obstacle automatically. The walking-caster-hitch typically utilizes a
single caster wheel.
In addition, two or more swing mowers equipped with the walking--~~aaster-
hitch can be
pulled behind one tractor.
In the drawings which form a part of this specification,
Fig. 1 is a top view of a swing mower operating with the tractor completely
outside of the
mower cutting width
Fig. 2 is a top view of a swing mower operating with the tractor partially
outside of the
mower cutting width
Fig. 3 is a top view of a swing mower operating with the tractor on the
centerline of the
mower cutting width
Fig. ~ is a top view of a swing mower in transport position
Fig. ~ is a fop view of an alternate version of the swing mov~rer~ without the
raise-lower hitch
fink
Fig. 6 is a side view of the caster wheel support of the alternate version of
the swing
mower shown in Fig. 5
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Fig. T is a top view of two swing mowers towed behind one tractor9 in a mowing
position
with the tractor operating completely outside of the mower cutting widths.
I=ig. ~ is a top view of two swing mowers towed behind one tractor, in a
mowing position
with the tractor operating partially outside of the mower cutting widths.
Fig. 7 is a top view of two swing rnowers towed behind one tu~actor, in a
mowing position
with the tractor operating approximately on the centerline of the front mower.
Fig. 7 is a top view of two swing rrryowers towed behind one tractor, in
transport position.
~ETAILEI~ IJESCRIPTI~N QF THE IN~JENTI~N
in a particularly advantageaus embodiment of the invention illustrated
walking«caster-hitch
assembly 10 is pivotally attached to the front of a pull-type mower 13 with a
horizontal
pivot axis 9 that is perpendicular to the forward motion of the mower. A
caster wheel 6 is
part of the walking-caster-hitch assembly 10 and is offset laterally ~~~ one
side of the
centerline of the mower 13. The caster wheel ~ is typically located slightly
behind the
horizontal pivot axis 9. The walking-caster-hitch assembly 1 l~ includes the
hitch pole 1 and
the cross hitch 5. The hitch pole 1 is laterally offset on the side of the
mower 1 ~ opposite
the caster wheel 6. The rear of the hitch pole 1 is pivotally attached to the
cross hitch ~
with a vertical pivot at the rear hitch pole pivot axis 4 and th,e front of
the hitch pole 1 is
pivotally attached to the tractor drawbar 3 at the front hitch pole pivot axis
2. The front of
the hitch pole 1 may be equipped with a swivel hitch as is cornrnor~ in the
industry.
Therefore the front of the mower 1 ~ is supported by a unique walking~caster-
hitch which
consists of the caster wheel fi to the rear of the horizontal pivot axis g on
one side of the
centerline of the mower, and the hitch pole 1 attached to the tractor drawbar
3 located
ahead of the horizontal pivot axis g and on the other side of the centerline
of the mower.
due to the geometry of the walking-caster-hitch, when the swing mower is in
normal
mowing position most of the weight of the front of the mower is supported by
the caster
wheel with a small vertical load being carried at the tractor drawbar.
The hitch swing cylinder 7 may be actuated to swing the hitch pole 1 relative
to the cross
hitch 5. Fig. 1 shows the swing mower operating with the tractor outside of
the mower
cutting width. Fig. 2 shows the swing mower operated with the tractor
partially within the
mower cutting width. F'ig. 3 illustrates a swing mower operating with the
tractor on the
centerline of the mower cutting width and fig. 4 shows a swing mower in
transport position.
The forward end of the compression strut i~ is pivotally attached to the hitch
pole 1. The
rearward end of the compression strut f3 is pivotally attached to the raise-
tower hitch link
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11, at a point 16 located above the horizontal pivot axis 9. llVhen the swing
mower is being
operating with the tractor outside of the mower cutting width as shown in
fig.l, the
compression strut 8 would have very little or no compressive forces. As the
hitch pole 1 of
the swing mower is moved so that the tractor moves toward the centerline of
the mower,
the compressive forces in the compression strut 8 increase.
Comps°essive forces in the
compression strut 8 are at maximum when the swing mower is in the transport
position fig.
4.
~ typical arrangement of the invention on a mower 13 is to have a raise-lower
hitch link 11
attached to the front of the mower 18 at horizontal pivot axis 15. As the
mower is raised
from cutting position to transport position, horizontal pivot axis 15
~°aises relative to
horizontal pivot axis 9. ~1s the horizontal pivot axis 18 rises relative to
horizontal pivot axis
9, the connection point 16 moves forward, putting greater force on the
Bompression strut 8.
Typically the swing mower would be designed so that when the hitch pole 1 is
swung into
the transport position as shown in fig.4 and when the mower is raised into
transport
position, the compressive forces in the compression strut 8 would be
sufficient to raise the
caster wheel 6 off of the ground. This would be very benefcial as caster
wheels easily
become unstable when on the ground at high transport speeds.
lllJhen mowing, especially in ditches, it is common to encounter obstacles
such as
signposts or guard rails. ~ne variation of the invention would be to have an
obstacle
sensor 12 located on the swing mower. 'This obstacle sensor 1 ~ could be
mechanical as
illustrated or some sort of electronic, light beam or acoustic sensing device.
Vllhen the
obstacle sensor 12 senses an object in the path of the mower 13, the hitch
swing cylinder
7 is actuated to swing the mower 13 away from the obstacle. once the obstacle
has been
cleared, the hitch swing cylinder 7 would be actuated to swing the mower 13
back to its
normal mowing position.
UVhen it is desired to pull two swing mowers behind one tractor, the front of
the tandem
hitch link 1? could be pivotally attached to the front swing mower. The rear
of the tandem
hitch link 17 is attached to the front of the hitch pole 1 of the rear swing
mower as
illustrated in figures 7-1 Q. The tandem hitch link could be pivoted using a
tandem hitch link
swing cylinder 18. This allows the rear swing mower to be offset adequately,
for operation
in the Butting position, relative to the front swing mower as shown in figures
7 -9. It also
allows the Pear Swing mower to be moved toward the centerline of the front
swing mower
for clearing obstacles and for transport position as shown in fig. 10.
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Power-tatce-off drive train components are shown on the figures in light,
dashed lines. tt is
obvious that the power train required to drive a swing mower is a simple;
mechanical drive
system that does not require any additional gearboxes or constant-velocity U
joints other
than the units required on a basic mower. tn addition, a simple mechanical
drive can be
used to drive the rear swing mower in a tandem swing mower arrangement,
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ELEMENTS NUMBERED ON FIGURES:
1. Hitch pole
2. Front hitch pole pivot axes
3. Tractor drawbar
4. Rear hitch pole pivot axis
5. Cross hitch
6. Caster wheel
7. Hitch swing cylinder
8. Compression strut
9. ~lorixontal pivot axis between cross hitch and raise-lower hitch link
10. iNaiking-caster-hitch assembly
11. Raise-tower hitch fink
12. ~bstacle sensor
13. Puii-type mower
14. Tractor
15. Horizontal pivot axis between mower and raise-lower hitch fink
16. Pivotal connection between compression strut and raise-Power hitch link
17. Tandem hitch fink
18. Tandem hitch fink swing cylinder
Prior art:
1. Pearen patent: Canadian #2241162
2. Schutte Fiex-Arm
3. U SA patent #4, 586, 724
David R. Hundeby
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