Note: Descriptions are shown in the official language in which they were submitted.
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DISC MOUNTING ASSEMBLY FOR A VERTICAL TILLAGE IMPLEMENT
FIELD OF THE INVENTION
The present invention relates to agricultural implements for vertical tillage
including a plurality of disc supporting tillage units supported on a main
frame, and more
particularly the present invention relates to a hub and shaft arrangement for
rotatably
supporting a ground engaging disc on the disc supporting arm of a respective
one of
the tillage units.
BACKGROUND
As described in US Patent Application Publication No. US 2012/0312569
by Redekop, in one known form of conservation tillage, the soil is minimally
disturbed
prior to planting in order to allow air to penetrate the mat of crop residue.
This technique
is variously known as minimum tillage, residue management, soil aeration or
seedbed
aeration. A farm implement, sometimes known as a vertical tillage implement,
is used
to cut the crop residue and penetrate a short distance into the surface of the
soil while
lifting the soil vertically to permit access of air to the soil.
A known construction of a vertical tillage implement comprises a main
frame supporting a plurality of tillage units thereon in which each tillage
unit comprises
a disc supporting arm which is resiliently mounted relative to the main frame.
A disc
assembly is then mounted on the trailing end of the disc supporting arm in the
form for
a shaft and a hub which rotatably supports a ground engaging disc on the
shaft.
During use of the vertical tillage implement, the soil is fractured in such a
manner that a considerable amount of side flowing soil and residue movement
results.
Maintenance of prior art hub and shaft arrangements due to penetration of soil
and
residue into the bearing thereof is thus a known concern.
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SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided a disc
assembly for use with a vertical tillage implement having a main frame
supporting a
plurality of tillage units thereon in which each tillage unit includes a disc
supporting
arm mounted on the main frame, the disc assembly comprising:
a shaft arranged to be mounted on the disc supporting arm of a
respective one of the tillage units;
a hub supported on the shaft such that the hub is rotatable about a
longitudinal axis of the shaft, the hub including:
an annular body portion supported concentrically about the shaft
to extend in an axial direction between an inner end and an opposing outer
end;
a disc mounting portion provided externally on the annular body
portion so as to be arranged to mount a ground engaging disc on the hub;
a cap portion arranged to enclose the outer end of the annular
body portion;
a first annular flange portion oriented circumferentially about the
shaft and protruding in the axial direction from the inner end of the annular
body
portion; and
a second annular flange portion oriented circumferentially about
the shaft and portion protruding in the axial direction from the inner end of
the annular
body portion;
the second annular flange portion being smaller in circumference
than the first annular flange portion so as to define a groove between the
first and
second annular flange portions which extends circumferentially about the shaft
at the
inner end of the annular body portion;
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an end plate mounted fixedly on the shaft so as to substantially enclose
the inner end of the annular body portion, the end plate including an annular
tongue
portion protruding axially from an interior side of the end plate so as to be
matingly
received within the annular groove between the first and second annular flange
portions for relative rotation therebetween.
The resulting sinuous path between the tongue portion of the end plate
and the pair of annular flange portions of the hub has been found to
considerably
minimize penetration of soil and residue through the rotatably interface of
the hub to
the interior of the hub where bearings are located. Accordingly this has the
advantage of minimizing maintenance required with regard to the bearings which
rotatably support the hub and disc on the shaft of each disc assembly on a
vertical
tillage implement.
Preferably there is provided a generally U-shaped clearance gap
between the annular tongue portion and the annular flange portions such that
the
annular body portion and the end plate do not directly contact one another.
A first radial gap portion between the tongue portion and the first annular
flange portion preferably increases in radial dimension in the axial direction
towards
an exterior of the annular body portion from a first end to a second end of
the first
radial gap. The first radial gap portion may be less than 0.050 inches in
dimension
along a full length in the axial direction between the first end and the
second end
thereof. More preferably, the first radial gap portion varies from a dimension
from
0.015 inches to 0.030 inches.
A first end gap portion in the axial direction between an inner end of the
tongue portion and the inner end of the annular body portion in proximity to
the first
end of the first radial gap, preferably has a dimension which is less than the
second
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end of the first radial gap. More particularly the first end gap may be less
than 0.050
inches in dimension and is preferably approximately 0.015 inches.
Preferably the first annular flange portion is substantially flush with an
exterior side of the end plate.
A second radial gap between the tongue portion and the second annular
flange portion preferably also increases in radial dimension in the axial
direction
towards an interior of the annular body portion from a first end to a second
end of the
second radial gap. The second radial gap is preferably less than 0.05 inches
in
dimension along a full length in the axial direction between the first end and
the
second end thereof. More preferably the first radial gap portion varies in
dimension
from 0.015 inches to 0.030 inches.
Preferably a second end gap is provided in the axial direction between a
free end of the second annular flange portion and the interior side of the end
plate
which has a dimension which is less than 0.050 inches, and more particularly
is
approximately 0.030 inches.
The interior side of the end plate may further include a shoulder portion
protruding axially inwardly at a location which is radially inwardly from the
tongue
portion and which is in close proximity to the second annular flange portion
so as to
be arranged to define a generally S-shaped clearance gap between the annular
flange portions of the annular body portion and the tongue portion and the
shoulder
portion of the end plate. Preferably the annular body portion and the end
plate remain
in a non-contacting relationship along a length of the S-shaped clearance gap
between an interior and an exterior of the annular body portion.
One embodiment of the invention will now be described in conjunction
with the accompanying drawings in which:
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of an example of a vertical tillage
implement upon which the disc assembly of the present invention is installed;
Figure 2 is a sectional view of a prior art disc assembly for a vertical
5 tillage implement;
Figure 3 is a sectional view of an enlarged portion of the prior art disc
assembly according to Figure 2;
Figure 4 is a perspective view of the disc assembly according to the
present invention;
Figure 5 is an end elevational view of the disc assembly according to
Figure 3;
Figure 6 is a sectional view along the line 6-6 of Figure 5; and
Figure 7 is an enlarged portion of the section view according to Figure 6.
In the drawings like characters of reference indicate corresponding parts
in the different figures.
DETAILED DESCRIPTION
Referring to the accompanying figures, there is illustrated a disc
assembly generally indicated by reference numeral 10. The disc assembly 10 is
suited for use with a vertical tillage implement 12 of the type shown in
Figure 1.
A typical vertical tillage implement 12 upon which the disc assembly is
installed includes a main frame 14 arranged for connection to a towing vehicle
for
movement across an agricultural field in a forward working direction. One or
more
tool bars 16 are mounted on the main frame to span horizontally and
transversely to
the forward working direction. A plurality of tillage units 18 are mounted on
each tool
bar. Each tillage unit includes a disc supporting arm 20 which is supported on
the tool
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bar by a respective resilient connection at the front end thereof such that
the support
arm trails downwardly and rearwardly from the front end to a rear end
supporting
respective disc assemblies 10 thereon. A spring element biases the disc
supporting
arm 20 downwardly for engagement of the disc assemblies at the rear end
thereof
with the ground while permitting upward deflection of the disc assemblies when
obstacles are encountered.
Each disc assembly 10 of the present invention has various features in
common with a prior art disc assembly shown in Figure 2. In particular, each
disc
assembly includes a shaft 22 arranged to be mounted in fixed arrangement to
the rear
end of the respective disc supporting arm 20. A hub 24 is rotatably supported
on the
shaft about a longitudinal axis of the shaft which is oriented generally
horizontally and
transversely to the forward working direction. The hub 24 comprises an annular
body
portion extending generally in the axial direction from an inner end 26 to an
opposing
outer end 28.
An interior diameter of the annular body is larger than the outer diameter
of the shaft received therethrough to provide radial space therebetween
locating two
bearings 30 at axially spaced positions along the shaft. The two bearings
comprise
an annular arrangement of bearings mounted at an incline to the axial
direction in
axially opposing arrangements relative to one another to provide radial and
axial
support in both directions to the hub relative to the shaft. The bearings are
arranged
in proximity to the inner and outer ends of the annular body portion
respectively.
A disc mounting portion 32 is mounted externally on the annular body
portion in the form of a flange extending about the circumference of the body
and
projecting radially outward therefrom perpendicularly to the axis of rotation.
Bolt holes
in the flange defining the disc mounting portion permit a ground engaging disc
34 to
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be fixed thereon such that the disc is rotatable with the hub relative to the
shaft.
A retainer nut 33 is fastened at the outer end of the shaft 22 to retain the
bearings 30 at respective positions in the longitudinal direction of the
shaft.
A cap member 36 is mounted in fixed relation across the outer end of
the annular body portion to fully enclose the outer end of the annular body
portion.
The outer end of the shaft is thus fully received within the interior of the
annular body
portion and cap member.
An end plate 38 is mounted in fixed relation to the shaft adjacent the
inner end of the annular body portion such that the end plate is arranged to
span and
substantially enclose the inner end of the annular body portion. The end plate
generally comprises a circular body having an exterior side oriented generally
perpendicularly to the axial direction. A plurality of wiper seals 40 are
supported at
the interior side of the end plate 38 such that the wiper seals extend
radially outward
from an interior mounted end to an outer end in rotating contact with a
corresponding
.. inner surface 42 of the annular body portion adjacent the inner end
thereof.
A suitable grease nipple 44 communicates through the wall of the
annular body at an intermediate location in the axial direction between the
disc
mounting portion and the outer end of the body. At the interior of the body,
the grease
nipple communicates with the longitudinal space between the two pairs of
bearings 30
to permit grease to fill the open interior of the body between the inner and
outer ends
thereof locating the bearings therein.
The disc assembly 10 of the present invention remains distinguished
from the prior art by the mating configuration between the inner end of the
annular
body portion and the end plate. In one example of a prior art configuration
shown in
Figure 2, the inner end of the annular body portion terminates at a single
collar
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shaped structure 46 defining the inner surface 42 against which the wiper
seals are
rotatably engaged at the interior side and defining an outer surface in
rotatable
engagement with an 0-ring seal 48_ In this instance, the end plate 38 is
provided with
a collar portion 50 having an interior diameter which is greater than the
outer diameter
of the collar structure 46 to permit the collar portion 50 to overlap the
collar structure
46. An annular groove in the interior surface of the collar portion 50
provides a
mounting location for the 0-ring 48. The seam between the inner end of the
annular
body portion and the end plate terminates at the exterior of the hub in a
radial
orientation. A large clearance gap is provided between the annular body
portion and
the end plate such that the 0-ring seal 48 in direct contact therebetween
provides the
primary resistance to soil penetration through the seam.
The disc assembly 10 of the present invention as shown in Figures 4
through 7 remains distinguished from the prior art in the configuration of the
inner end
26 of the annular body portion and in the configuration of the end plate 38.
More
particularly, the annular body portion in this instance comprises a first
annular flange
60 which is integral with the annular body portion and which is oriented to
extend
about a full circumference of the shaft concentrically therewith. The first
annular
flange is flush with the outer diameter of the annular body portion at the
outer side
thereof and extends in the axial direction beyond the inner end of the body to
a free
end which is flush with the exterior side of the end plate 38.
The inner end of the annular body portion also includes a second flange
62 which is integral with the body to extend circumferentially about the
shaft,
concentrically therewith. The second annular flange 62 has an outer diameter
which
is less than the inner diameter of the first annular flange and an inner
diameter which
is substantially flush with the adjacent inner surface of the annular body
portion.
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The radial distance between the first and second annular flanges
defines an annular groove extending generally axially from a terminal end
surface 64
joined between the first and second annular flanges to an opposing end which
receives a portion of the end plate therethrough as described in further
detail below.
The end surface 64 defines the inner end of the annular body portion from
which the
first and second annular flanges project.
The outer diameter of the end plate 38 in this instance corresponds
approximately to the inner diameter of the first annular flange 60 and
supports an
annular tongue portion 66 thereon. The tongue 66 comprises an annular flange
extending about a full circumference of the shaft and which projects in an
axial
direction from an interior side of the end plate to extend into the annular
groove 63.
The end plate 38 also includes a shoulder 68 located at the interior side
of the end plate at a location which is radially inward from the tongue 66.
The
shoulder 68 defines a surface projecting in the axial direction about a full
circumference of the shaft in close proximity to the inner surface of the
second
annular flange 62. The wiper seals 40 are mounted further towards the interior
of the
annular body portion in the axial direction relative to the shoulder 68.
In the arrangement described above, the tongue 66 received within the
annular groove 63 between the first and second annular flanges defines a
generally
U-shaped clearance gap. The clearance gap is continuous about the free end of
the
second annular flange due to the close proximity to the shoulder 68 such that
the
overall seam between the inner end of the annular body portion and the end
plate is
generally S-shaped in profile from an exterior opening which faces in the
axial
direction at the periphery of the end plate, about the tongue 66, and about
the second
annular flange 62 to the opposing end which is open in an axial direction
towards the
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interior of the annular body portion. The overall dimension of the gap between
the
annular body portion and the end plate may be generally in a range between
0.010
inches and 0.050 inches. In the illustrated embodiment, the gap ranges between
0.015 inches and 0.030 inches. The gap remains unobstructed to provide a non-
5 contacting mating connection along a full length of the gap from the
exterior to the
interior of the annular body portion.
The overall gap includes a first radial gap portion 70 spanning in the
axial direction between a first end at the free end of the tongue
corresponding to the
end surface 64 of the annular groove to an opposing second end at the exterior
side
10 of the end plate 38. The dimension of the gap in the radial direction
widens from the
first end having a dimension of 0.015 inches to the second end having a
dimension of
0.030 inches.
The overall gap further includes a first end gap portion 72 which is a gap
in the axial direction but which spans radially across the free end of the
tongue 66.
The dimension of the gap in the axial direction between the annular body
portion and
the end plate is 0.015 inches.
The overall gap also includes a second radial gap portion 74 which
spans in an axial direction from a first end in proximity to the free end of
the tongue
and the end surface 64 of the annular groove to an opposing second end at the
interior side of the end plate 38. The dimension of the gap in the radial
direction is
similar to the first radial gap portion 70 in that it widens from a dimension
of 0.015
inches at the first end to a dimension of 0.030 inches at the second end.
Furthermore, the overall gap includes a second end gap portion 76
which is a gap in the axial direction between the free end of the second
annular flange
62 and the corresponding portion at the interior side of the end plate 38. The
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dimension of the gap in the axial direction is 0.030 inches.
The small clearance dimension along the full length of the gap provides
minimal opportunity for disturbed soil and debris to enter the gap into the
interior of
the annular hub portion where the bearings are located. Furthermore, by
orienting the
exterior opening of the gap to be directed in an axial direction rather than
the radial
arrangement of the prior art, disturbed soil is less likely to be forced
radially inwardly
through the seam to the interior of the hub portion. By further arranging the
first radial
gap portion 70 to become wider in radial dimension towards the exterior open
end,
any debris entering the gap is more likely to be encouraged to navigate to the
exterior
towards the widening opening and thus be restricted from further penetration
by the
narrowing gap dimension towards the interior of the annular body portion.
Since various modifications can be made in my invention as herein
above described, and many apparently widely different embodiments of same made
within the spirit and scope of the claims without department from such spirit
and
scope, it is intended that all matter contained in the accompanying
specification shall
be interpreted as illustrative only and not in a limiting sense.
