Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02286410 1999-10-14
GROUND OPENER WITH IMPROVED DISC SCRAPER MOUNTING
BACKGROUND OF THE INVENTION
The present invention relates generally to ground opener units,
particularly to planting units for forming a furrow in the ground and
depositing
seeds therein. More particularly, the present invention relates to equipment
of
the type noted above employing improved scraper devices for cleaning a
surface of the disc opener used therein.
Planting assemblies of the type noted above are typically arranged such
that the opener disc is held at an angle from the forward direction of travel
so
that the disc has a leading face and a trailing face. The disc displaces soil
laterally as it travels forward and opens a furrow following the trailing
face. In
wet conditions, soil tends to stick to the trailing face so it is common to
provide
a scraper to clean the disc. The scraper also acts to prevent loose soil from
falling back into the furrow until the seed is properly placed into the
furrow.
The disc is subject to flexing as lateral forces are applied to the disc when
opening the furrow. The scraper must be held close to the disc but not so
tightly as to cause a braking action on the disc; therefor the scraper must be
allowed to flex and move with the disc's deflection.
The prior art has provided a variety of scraping devices for use in angled
disc openers. Reference may be had for example to U.S. Patents 4,760,806 and
5,787,994. Additionally, an earlier version of an implement developed by the
assignee of the present invention employed a bracket which supported the disc
scraper and which included a three bolt triangular pattern for adjusting the
angle of the bracket. The bracket pivoted on the head of a carriage bolt as
the
three fasteners were tightened to effect angle adjustment. However, this prior
design had a number of disadvantages in that adjustment of one fastener
required corresponding readjustment of at least one of the other fasteners;
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adjustment of the desired angle was complicated and time consuming with the
three fastener system and the bracket often became permanently deformed if
one fastener was tightened without first loosening the others. Additionally,
this
rigid adjustment system did not allow the scraper to flex in response to
irregularities or flexing of the disc blade.
SUMMARY OF THE INVENTION
The objects of the present invention are to provide disc scraper
assemblies permitting quick and ready adjustment of the scraper to provide a
scraper mounting giving a degree of resiliency to allow scraper flexing in
response to disc irregularities or flexing of the disc during use and
furthermore
to provide for resiliency or rocking motion of the scraper about plural axes
thereby to assist in keeping the scraper edge parallel to the disc surface
while
the disc flexes during use, thereby to ensure proper cleaning at all times.
A scraper assembly for a disc opener in accordance with the invention in
one aspect includes a scraper plate defining a scraper edge for contacting and
scraping a disc, said scraper plate defining a mounting region remote from
said
edge; a scraper plate mount adjacent said mounting region, a resilient
component interposed between said mounting region and said plate mount, and
a spaced pair of fasteners extending through said mounting region to secure
said scraper plate and resilient component to said scraper plate mount, said
pair
of fasteners being located in selected positions in said mounting region
relative
to said resilient component~such that said scraper plate is capable of being
tilted
or rocked relative to said scraper plate mount in response to forces applied
to
said scraper plate.
The above-noted resilient component comprises a pad of resilient
material. Preferably, said scraper blade tends to tilt about at least first
and
second axes which intersect one another.
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In a preferred form of the invention said first axis extends generally
parallel to a line extending between said fasteners, said scraper edge being
located to one side of and spaced from the first axis and a substantial
portion of
the area of said resilient pad being located to the opposite side of said axis
such
that moments of force about said first axis are developed to assist said
scraper
edge to follow a disc surface.
In a preferred form of the invention said scraper edge is located to one
side of and spaced from the first axis and a substantial portion of the area
of
said resilient pad is located to the opposite side of said axis such that
moments
of force about axis are developed to assist said scraper edge to follow a disc
surface.
In a preferred embodiment of the invention said fasteners are capable of
being tightened or loosened both individually and collectively to vary the
degree of compression of said resilient pad, with collective tightening of
said
fasteners tending to rock said scraper plate about the first axis and to
increase
the force applied to a disc surface via said scraper edge while differential
tightening of said fasteners tends to rock said scraper plate about said
second
axis whereby to affect the alignment between said scraper edge and a disc
surface.
Further according to a preferred embodiment said scraper edge is
disposed such that disc surface irregularities encountered by said scraper
edge
tend to create moments of force and rocking motion of said scraper plate about
both the first and second axes.
In a further aspect of the invention the above described scraper assembly
is combined with a ground opener unit including an arm attachable to an
implement frame and having a disc rotatably mounted to said arm for forming
a furrow in the ground. Said disc is preferably held, in use, at an angle to
the
forward direction of travel to displace soil and open a furrow so that said
disc
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has a leading surface and a trailing surface with said scraper assembly being
adapted to scrape said trailing surface of the disc.
Further aspects of the invention are set forth in the appended claims.
A preferred embodiment of the invention will now be described with
reference being had to the accompanying drawings.
BRIEF DESCRIPTION OF THE VIEWS OF DRAWINGS
Fig. 1 is a side elevation view of a disc ground opener unit incorporating
the disc scraper mounting system in accordance with an embodiment of the
mventlon;
Fig. 2 is a rear end elevation view thereof;
Fig. 3 is a top plan elevation view thereof;
Fig. 4 is a rear perspective view of the opener disc, arm and bracket
assembly showing the resiliently mounted scraper blade in position adjacent a
surface of the disc;
Fig. 5 is a further perspective view similar to Fig. 4 with certain
otherwise "hidden" structures shown in phantom;
Fig. 6 is a side elevation view of the scraper plate per se with the
resilient pad being partly shown in phantom; and
Fig. 7 is a perspective view of the seed tube showing both the seed tube
mount and the scraper mount.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figs. 1, 2 and 3 show an opener assembly having the forward end of f,-
shaped opener arm 10 pivotally mounted to a main mounting arm 12 at pivot
point 10a. Mounting arm 12 is adapted to be attached to a main implement
frame (not shown) to which are attached a plurality of spaced apart opener
assemblies. The trailing end of opener arm 10 pivotally supports a disc furrow
opener 14 and an accessory bracket 16, opener 14 having a rotation axis A
coincident with the pivot axis between the bracket 16 and arm 10. The
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accessory bracket 16 is further connected by a pivot link 18 extending between
pivot 18a on the lower end of mounting arm 12 and a pivot 18b on accessory
bracket 16 so as to form a parallel linkage arrangement with the opener arm 10
which maintains a constant orientation of the accessory bracket 16 as the
opener arm 10 and link 18 pivot relative to the mounting arm 12.
A seed tube 20, disc scraper assembly 22, gauge wheel 24, and packer
(closing) wheel 26 are supported on the accessory bracket 16. (Disc scraper
assembly 22 including its mounting will be described in detail hereafter.) The
gauge wheel 24 is rotatably mounted to depth adjustment mechanism 28 which,
in turn, is mounted to accessory bracket 16. Wheel 24 is positioned adjacent
one face of the disc opener 14 (Fig.3). The wheel 24 has a resilient shallow
tire
extending around its perimeter having a lip 24a which engages the adjacent
face of the opener disc 14 to clean the latter during rotation in known
fashion.
The gauge wheel 24 may be adjusted generally vertically relative to bracket 16
by rotating knob 28a to rotate an adjustment screw (not shown) of depth
adjustment mechanism 28. Gauge wheel 24 thus acts as an adjustable depth
control to limit the penetration of the disc opener 14 into the soil, as the
wheel
24 rolls on the surface of the ground.
The pivot axis defined by pivot point 10a is angled relative to mounting
arm 12 to provide a pivot angle B (see Fig.3). The disc opener 14, gauge wheel
24, arm 10, link 18 etc. are all oriented at angle B to the forward direction
of
travel T of the opener assembly to effect opening of the soil in generally
well
known fashion.
The packer wheel 26 is pivotally connected to the accessory bracket 16
by way of a rearwardly extended packer arm 30 (Fig. 5), and a coil tension
spring 32 is connected between the packer arm 30 and accessory bracket 16 to
bias the packer wheel 26 toward the ground to help close the furrow opened by
disc 14 after seeds have been implanted therein via the seed tube 20 in known
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fashion.
A downpressure or biasing assembly 34 as described in detail in our
copending application Serial No. 2,250,677 is connected between the opener
arm 10 and the mounting arm 12 to bias the opener arm 10 toward the ground,
with the reaction being received through the mounting arm 12 through to the
main implement frame (not shown). The biasing assembly 34 includes a
tension rod 36 having front and rear ends. A rear plate 38 is secured to the
rear
end of rod 36 and the front end of the tension rod 36 slidably extends through
a
hole in front plate 40. The front plate 40 is rigidly connected to the
mounting
arm 12. First and second coil springs 42, 44 are fitted over the tension rod
36
and held between the front and rear plates. The front end of the tension rod
36
is pivotally connected to the opener arm 10 at point 36a spaced from pivot 10a
so that pivoting movement of the opener arm 10 causes a displacement of the
tension rod 36 through the front plate 40. This changes the distance between
1 S the front and rear plates 40, 3 8 thus effecting a displacement of the
coil springs
42,44. The springs resist compressive displacement and constantly bias the
opener arm 10 and the complete opener assembly toward the ground.
The first and second springs 42, 44 are arranged in series between the
plates 40, 38. The 1st and 2nd springs abut each other with their opposite
ends
abutting the rear and front plates respectively. A sleeve 46 attached to the
rear
plate 38 extends through the inside of the first coil spring 42 and partially
inside the second coil spring 44 to keep the springs 42, 44 in abutting
alignment. The tension rod 36 includes a threaded stud 37 which extends
through plate 38 and into a.central bore in the forward end portion of tension
rod 36 to allow the operator to adjust the effective length of the tension rod
36
by rotating stud 37 to set the precompression loading on the springs 42, 44,
thus
setting the range of downpressure available for the working range of the
planting tool.
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Referring particularly to Figs. 4-7 the disc scraper assembly 22 includes
scraper plate 50 flexibly secured adjacent one surface of the disc opener 14
to
scrape materials off the disc surface as it operates in the soil. It also
prevents
soil from falling back into the furrow before the seed can be properly placed,
and contains the seed within the furrow until it settles to rest at the
bottom. The
scraper plate 50 must flex in response to contact with the disc 14 as the disc
flexes in response to varying forces on its surfaces as it operates in the
soil.
As noted above, the disc 14 is oriented at angle B from the transverse so
that as it is drawn through the soil it has a leading face and a trailing face
52
whereby the leading face displaces soil laterally and a furrow is opened
following the trailing face. The scraper plate 50 is positioned adjacent the
trailing face 52. The disc 14 is subject to deflections as the leading face
acts to
displace the soil as noted above. The scraper plate 50 is mounted such that it
is
able to flex when pressed on by the deflecting disc blade so that there is
minimal reaction from the scraper plate 50 which would otherwise cause a
braking action on the disc, preventing it from rotating.
As noted above, this embodiment of the invention allows the scraper
plate position with respect to the disc trailing surface 52 to be adjusted and
also
allows the scraper plate to deflect from this position in response to the disc
deflection. Two threaded fasteners 54 secure the upper end mounting region 51
of scraper plate 50 to the scraper mount 56 (Fig. 7) with a thick resilient
pad 58
of rubber or rubber-like material secured between scraper mount 56 and
mounting region 51. Scraper mount 56 is fixed to the lower end of the seed
tube 20, the latter in turn being bolted via seed tube mount 57 to the
accessory
bracket 16. A 1 st axis A-A (see Figs. 4 and 6) is shown as generally parallel
to,
but slightly offset from a line extending between the two fasteners 54. A 2nd
axis B-B is shown as intersecting the 1 st axis and passing through a point
generally intermediate the two fasteners 54. As will be appreciated, the
rubber
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pad 58 does not have 2 strict axes per se. Rather it deflects in multiple
directions. Fasteners ~4 will constrain the deflection so that there appears
to be
a predominant axis A-A. Axis B-B, however, as best understood, tends to
wander within a range of angles. It likely stays within a region of angles so
that
it remains between the fasteners 54 and passes through a centroid of the
resilient pad 58. The centroid itself, will wander somewhat depending on what
part of the pad 58 is more compressed. It is, however, convenient to refer to
axes A-A and B-B keeping~in mind that their locations are subject to some
variations. The scraper plate 50 has an edge 60 at its lower end inclined
obliquely and which is positioned along the disc trailing surface 52 for
scraping
the latter, the upper end of the scraper plate 50 being held firm against the
resilient pad 58 by the fasteners 54 which are somewhat intermediate of the
two
scraper ends. Most of the area of the resilient pad 58 is on that side of the
1 st
axis A-A which is toward the upper end of the scraper plate. When both
fasteners 54 are adjusted in generally equal portions, the scraper plate 50 is
adjusted about the 1st axis A-A. (When both these fasteners 54 are tightened
moments of force about axis A-A created by that portion of resilient pad 58
located above axis A-A tend to cause the scraper plate edge 60 to press more
closely to the disc surface at the lower end) . When only one fastener 54 is
tightened, resistance by the resilient pad 58 near the other fastener causes
the
scraper plate to tilt or rock slightly about the 2nd axis (B-B), changing the
alignment between the scraper edge 60 and the disc trailing surface 52.
Ideally
the scraper edge 60 is held parallel to and against the disc trailing surface
with a
relatively small force and the scraper plate 50 will tilt or rock slightly
about
both the 1 st and 2nd axes A-A and B-B to accommodate disc deflections etc.
so that the scraper edge 60 remains generally parallel to the disc surface
where
it contacts the disc. The resilient pad 58 provides enough force to hold the
scraper plate in its preferred position and so as to prevent soil from
pressing
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between the scraper plate ~0 and the disc surface 52 and forcing the scraper
plate away from the disc. This prevents soil from creating a plug between the
scraper plate and disc which might otherwise possibly plug the seed tube as
well.
Some Advantages of Present Invention are that
two fastener adjustment is relatively simple
the resilient pad allows for scraper plate adjustment by adjusting only
one of the fasteners
the resilient pad provides bias of the scraper plate toward the disc
surface while allowing flexing in response to disc deflection etc.
the resilient pad provides resilient bias of the scraper plate about
multiple axes to keep the scraper edge parallel to the disc surface while
the disc flexes during use.
Preferred embodiments of the invention have been described and
illustrated by way of example. Those skilled in the art will realize that
various
modifications and changes may be made while still remaining within the spirit
and scope of the invention. Hence the invention is not to be limited to the
embodiments as described but, rather, the invention encompasses the full range
of equivalencies as defined by the appended claims.
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