Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02714719 2010-09-15
CROP LIFTER WITH RELEASABLE TIPS
This invention is in the field of cutting headers such as are used in
agriculture for cutting
crops for harvest and the like, and in particular with crop lifters mounted on
such headers
to increase crop gathering and retention in the harvesting machine.
BACKGROUND
For various reasons crops sometimes are lying so close to the ground that it
is difficult to
cut them with a conventional harvest header. Some crops are inherently short,
while
others may be taller, but are prone to fall down when they reach maturity.
Heavy rain or
hail can also cause crop to be lying close to the ground at harvest time.
Typically the knife on cutting headers comprises a knife bar extending along
the front
lower edge of the header, with a plurality of triangular knife sections
attached to the bar
such that the apex of the triangle extends forward from the bar. The exposed
side edges
of the knife sections are sharpened. Guards are attached to the front lower
edge of the
header and serve to protect the knife sections from breakage when contacting
stones and
like obstructions. The guards comprise pointed guard fingers extending
forward, and the
knife moves back and forth along the edge of the header in a slot cut
laterally through the
guard fingers. In addition to protecting the knife, the guard fingers also
enable the knife
sections to cut the crop. As the knife section moves back and forth it pushes
crop against
the sides of those portions of the guard finger that are above and below the
slot, shearing
the crop stalks.
A conventional knife is a few inches above the ground when the header is in
its lowest
position, such that very short or downed crop material will pass under the
knife and be
lost. Many different kinds of "crop lifters", as they have come to be known,
have been
developed over the last century and more. Typically these crop lifters are
attached to the
header and/or the forward extending point of the guard finger, and provide an
arm of
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various designs that rides along the ground ahead of the knife. A lifting
finger extends at
a shallow angle from the front of the arm back and over the knife. As the
header moves
down the field, the arm rides along the ground and under the downed crop
stalks, which
then are lifted and pass over the lifting finger to the knife, where they are
cut and
continue moving onto the header from where they can be passed to the
harvester, swather
table, or the like.
United States Patent Numbers 700,029 and 791,022 to Gatenmann, 2,734,332 to
Fisher,
2,892,298 to Chaney, 2,960,814 to. Babcock, and Canadian Patent Number 407,654
to
Young disclose such a crop lifter that is pivotally attached to the header so
as to be able
to move up and down to follow the ground. The Babcock and Fisher devices float
on the
ground, while the others are biased toward the ground by springs. United
States Patent
Number 4,120,138 to Schumacher illustrates a crop lifter that is fixed to the
header
instead of pivoting, but is made of spring steel so that same may move up and
down to
follow the ground.
The front portion of a pivotally attached crop lifter like Gatermann rides
along on the
ground and so typically the lifters have an up-turned ski-type front end so
that the lifter
rides along the ground but does not dig into the ground. These lifters have
various
configurations of length, width, shape, and so forth with some shapes better
suited for
some conditions than others. The lifters also change shape as contact with the
ground
wears material away from the lifter, and when the shape becomes unsuitable for
the
purpose, the lifter must be changed.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a crop lifter apparatus
for cutting
headers on harvesting equipment that overcomes problems in the prior art.
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In a first embodiment the present invention provides a crop lifter apparatus
for
attachment to a cutting header, the cutting header having a knife and guards
attached to a
lower front edge thereof with guard fingers of the guards extending forward
from the
header. The apparatus comprises a base member adapted to be attached to a
guard finger
about a lifter pivot axis oriented substantially horizontally and
perpendicular to an
operating travel direction of the header. A first lifter tip with a first
configuration is
releasably attachable to the base member at a mounting position such that the
first lifter
tip extends forward from the base member, and a second lifter tip with a
second
configuration different from the first configuration is releasably attachable
to the base
1.0 member at the mounting position such that the second lifter tip extends
forward from the
base member. A bias element is operative to exert a bias force on the base
member
urging a front portion of the base member forward of the lifter pivot axis to
pivot
downward about the lifter pivot axis, and the bias force urges the base member
to bear
against a stop.
In a second embodiment the present invention provides a cutting header for a
harvesting
implement. The cutting header comprises a knife and guards attached to a lower
front
edge of the cutting header, wherein guard fingers of the guards extend forward
from the
header. A base member is attached to a guard finger about a lifter pivot axis
oriented
substantially horizontally and perpendicular to an operating travel direction
of the header.
A first lifter tip with a first configuration is releasably attachable to the
base member at a
mounting position such that the first lifter tip extends forward from the base
member, and
a second lifter tip with a second configuration different from the first
configuration is
releasably attachable to the base member at the mounting position such that
the second
lifter tip extends forward from the base member. A bias element is operative
to exert a
bias force on the base member urging a front portion of the base member
forward of the
lifter pivot axis to pivot downward about the lifter pivot axis, and wherein
the bias force
urges the base member to bear against a stop.
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The present invention thus provides a lifter with interchangeable tips that
can be changed
to suit crop and soil conditions, or replaced when worn out. The tips can also
be readily
subjected to hardening procedures to reduce wear without adversely affecting
the main
base member of the apparatus.
DESCRIPTION OF THE DRAWINGS
While the invention is claimed in the concluding portions hereof, preferred
embodiments
are provided in the accompanying detailed description which may be best
understood in
conjunction with the accompanying diagrams where like parts in each of the
several
diagrams are labeled with like numbers, and where:
Fig. 1 is a schematic top view of a knife of typical cutting header of the
prior art;
Fig. 2 is a schematic side view of an embodiment of a crop lifter apparatus of
the
present invention;
Fig. 3 is a schematic rear perspective view of an alternate embodiment of a
crop lifter
apparatus of the present invention;
Fig. 4 is a schematic exploded side view of the embodiment of Fig. 3;
Fig. 5 is a schematic side view of a further alternate embodiment of a crop
lifter
apparatus of the present invention.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
Fig. I schematically illustrates a typical cutting header I of the prior art
comprising a
knife extending along the front lower edge of the header, which is moved along
a field in
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an operating travel direction T. The knife 2 comprises a plurality of
triangular knife
sections 3 attached to a knife bar 5 such that the apex 7 of the triangle
extends forward
from the bar 5. Guards 9 are attached to the front lower edge of the header 1
with guard
bolts 11 and serve to protect the knife sections 3 from breakage when
contacting stones
and like obstructions, and to provide a shearing edge for the knife sections
3. The guards
9 comprise pointed guard fingers 13 extending forward from the header.
An embodiment of a crop lifter apparatus 15 of the present invention for
attachment to
the cutting header 1 is schematically illustrated in Fig. 2. The apparatus 15
comprises a
base member 17 adapted to be attached to a guard finger 13 about a lifter
pivot axis PA
oriented substantially horizontally and perpendicular to an operating travel
direction T of
the header. In the illustrated apparatus 15, the base member 17 is mounted to
the guard
finger 13 simply by a bolt, pin, or the like through corresponding holes in
the base
member 17 and guard finger 13 which provides the lifter pivot axis PA.
A first lifter tip 19A with a first configuration is releasably attachable to
the base member
17 at a mounting position 21 such that the first lifter tip 19A extends
forward from the
base member 17. A second lifter tip 19B with a second configuration different
from the
first configuration is also releasably attachable to the base member 17 at the
same
mounting position 21 such that the second lifter tip 19B extends forward from
the base
member 17. When the header is lowered and working the tips 19 will ride along
on the
ground moving up and down about the lifter pivot axis PA.
The configurations of the first and second lifter tips 19A, 19B can be
selected to suit the
soil and/or crop conditions that will be encountered during use, and the tips
can be
quickly interchanged to suit changing conditions. For example where the soil
is hard and
dry and the crop is lying close to the ground first lifter tip 19A can be
narrow with only a
short upturned front ski shape to avoid digging into the ground. Where the
soil is soft,
such as sandier soils, a longer upturned front ski shape can be provided, and
a wider
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bottom skid plate could be provided as well. Only two interchangeable lifter
tips 19 are
illustrated to demonstrate the interchangeability of the tips 19 however it is
contemplated
that any number of different tips 19 with different configurations for
different conditions
could be provided.
The separation of the base member 17 from the lifter tips 19 also conveniently
allows the
tips to be heat treated or other wise hardened to reduce wear. Such hardening
treatments
typically cause the hardened metal to become brittle and subject to breakage.
The longer
base member 17 can thus be made out of malleable steel which is more suitable
for
resisting breakage, while the wearing tips can be hardened and then attached.
A bias element, illustrated as compression spring 23, is operative to exert an
upward bias
force BF on a rear portion 17R of the base member 17 which urges the front
portion 1.7F
of the base member 17, located forward of the lifter pivot axis PA, to pivot
downward
about the lifter pivot axis PA. The bias force BF urges the base member
against a stop 25
that bears against the bottom of the guard finger 13 and so prevents downward
movement
of the front portion 17F of the base member 17 beyond a desired position. In
the
illustrated apparatus 15, the stop 25 is adjustable by moving the stop arm 27
up and down
in the stop bracket 29. The slope of a lifter tip 19 attached to the front of
the base
member 17 when the base member 17 bears against the stop 25 can thereby be
adjusted to
suit soil and crop conditions. The slope of the lifter tips 19 when the base
member bears
against the stop 25 essentially dictates the angle at which the tips 19 will
first contact the
ground when the header is lowered to a working position, or when the header
rises over a
lump and then comes back down, and the tips 19 then pivot upward against the
bias force
BF about the lifter pivot axis PA in reaction to the force of contacting the
ground.
In the illustrated apparatus 15, the mounting point 21 is at the front end of
the base
member 17 where a lug 31 is configured to slide into a recess 33 defined in
rear ends of
the lifter tips 19. Corresponding lateral apertures 35 are defined through
rear ends of the
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lifter tips 19 and the lug 31 at the front end of the base member 17. The
corresponding
lateral apertures 35 are aligned when one of the lifter tips 19 is attached to
the front end
of the base member 17 and a fastener, such as a screw, roll, pin, bolt, or the
like extends
through the corresponding lateral apertures 35 to attach the tip.
Thus the lifter tips 19 can be quickly changed to suit soil and/or crop
conditions. The
illustrated apparatus 15 also provides a removable lifter finger 37 releasably
attached to
the base member 17 in a socket or the like defined by the base member 17. The
lifter
finger 37 extends rearward at an upward slope from a rear portion 17R of the
base
member 17 to a rear end of the lifter finger 37R located above and rearward of
the knife
2. In some crop conditions, such as where it is sometimes required to reverse
the
direction of travel such a rearward extending lifter finger 37 can be caught
in the crop and
cause damage and so it may then be advantageous to remove same.
Figs. 3 and 4 schematically illustrate an embodiment of a crop lifter
apparatus 115 of the
present invention where the base member 117 is adapted to be attached to a
guard finger
113 about the lifter pivot axis PA by a guard finger bracket 141 that is
adapted to be
attached to the guard finger 113 by an engagement mechanism 143 that has a
socket 145
into which the end of the guard finger 113 is inserted and has a slot 147 at
the rear end
that engages a guard bolt attaching the guard to the header such as is known
in the prior
art.
The base member 117 is then pivotally attached to the guard finger bracket 141
about the
lifter pivot axis PA. As schematically illustrated in the exploded side view
of Fig. 4, the
front end 141F of the guard finger bracket 141 is inserted into the rear end
117R of the
base member 117 and a torsion spring 123 is connected to or engages the guard
finger
bracket 141 and the base member 117. A pin or bolt is inserted into
corresponding holes
149 in the finger bracket 141 and base member 117. The torsion spring 123
provides the
bias element and exerts the downward bias force BF between the guard finger
bracket
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141 and the base member 117 about the lifter pivot axis PA urging the front
end of the
base member 117 downward. The first and second lifter tips i 19A, 119B are
releasably
attachable to the mounting position at a forward end of the base member 117 as
described
above with lug 131 inserted into recess 133 in the rear end of each lifter tip
119. The
illustrated apparatus 115 also provides a removable lifter finger 137
releasably attached
to the base member 117 in a socket 148 defined by the base member 117. The Her
finger 137 extends rearward at an upward slope from the base member 117 to a
rear end
of the lifter finger located above and rearward of the knife when attached to
the guard
finger 113.
A screw 127 in the base member bears against a stop 125 on the guard finger
bracket 141
to provide the required stop, and turning the screw 127 adjusts the effective
position of
the stop 125 to adjust the slope of the lifter tip 119 attached to the front
end of the base
member 117.
Fig. 5 schematically illustrate a further embodiment of a crop lifter
apparatus 215 of the
present invention where the base member 217 is adapted to be attached to a
guard finger
213 about the lifter pivot axis PA by a guard finger bracket 241 adapted to be
attached to
the guard finger 213 as described above for the apparatus 115 of Figs. 3 and
4. A lifter
finger bracket 251 is attached to a front portion of the base member 217, and
a lifter
finger 253 is engaged in the lifter finger bracket 251 such that the lifter
finger 253
extends forward from the lifter finger bracket 251.
As above, first and second lifter tips 219A, 219E are releasably attachable to
the
mounting position 221 which in this apparatus 215 is located at a forward end
of the lifter
finger 253 where a lug 231, provided by the end of the lifter finger 253, is
inserted into a
recess in the rear end of the tips 219. In this apparatus 215 as illustrated,
the lifter finger
253 includes a rear portion 237 that extends rearward at an upward angle from
the lifter
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finger bracket 251 to a rear end of the lifter finger 253 located above and
rearward of the
knife when the apparatus 215 is attached to the guard finger 213.
Thus the present invention provides a lifter with interchangeable tips that
can be changed
to suit crop and soil conditions. The tips can also be readily hardened to
reduce wear
without adversely affecting the malleability of the main base member of the
apparatus.
Further the tips can be replaced when excessively worn from contact with the
ground.
The foregoing is considered as illustrative only of the principles of the
invention.
Further, since numerous changes and modifications will readily occur to those
skilled in
the art, it is not desired to limit the invention to the exact construction
and operation
shown and described, and accordingly, all such suitable changes or
modifications in
structure or operation which may be resorted to are intended to fall within
the scope of
the claimed invention.
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