Note: Descriptions are shown in the official language in which they were submitted.
CA 02307176 2000-04-27
HEADER WITH FLEXIBLE CROP CUTTING KNIFE
This invention relates to header of a crop cutting apparatus such as a
swather or a combine harvester which includes a flexible cutting knife.
BACKGROUND OF THE INVENTION
A header for a crop harvesting machine generally comprises a main
longitudinal support member in the form of an elongate tube which extends
across
substantially the full width of the header frame and defines a main structural
member
for the header frame. The tube carries a plurality of forwardly and downwardly
extending support beams which include a first portion extending downwardly and
a
second portion attached to a lower end of the first portion and extending
forwardly
therefrom toward a forward end of the support beams. The cutter bar is
attached to
the forward end of the support beams and is thus held thereby in a position
generally
parallel to the main support tube.
Many headers are of a type in which the cutter bar is intended to be in
a fixed rigid position relative to the main support tube so that the cutter
bar is not
intended to flex or float relative to the main structural tube in response to
changes in
ground contour.
This rigid type of header has the advantage that it allows more
accurate control of the position of the fingers or bats of the reel relative
to the cutter
bar so as to more accurately control the crop as it is swept onto the cutter
bar and
the table rearwardly of the cutter bar.
In this rigid header type, therefore, the support beams extending
forwardly from the main structural tube are substantially rigid and hold the
cutter bar
in fixed position.
Alternative types of header mount the cutter bar for floating or flexing
movement relative to the main structural support tube. This type of header is
used
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2
to provide an improved action in following the contour of the ground and is
advantageous in some circumstances. This type of header however has the
disadvantage that the flexing or floating of the cutter bar relative to the
main support
tube causes movement of the cutter bar relative to the bats or fingers of the
reel so
that it is no longer possible to maintain a close tolerance between the bats
or fingers
and the cutter bar.
Various manufacturers provide a flexing cutter bar structure for
example the Soybean Header manufactured by Case IH under the serial No 820 or
1020.
Other types of header provide a cutter bar which is relatively rigid but
can float upwardly and downwardly relative to the main structural support tube
of the
header. This type of header again is used to allow close floating action of
the cutter
bar on the ground surface and one example is shown in the "Dial-a-matic Header
Height Control" available for various Deere and Company combine harvesters.
This
floating action of a cutter bar however occurs relative to the main structural
tube and
therefore relative to the reel so that the cutter bar to reel co-operation
cannot be
optimized.
When cutting crops right at the ground it will be found that the cutter
bar of larger headers needs to be somewhat flexible to follow the ground
contour. It
is known that rigid headers are conventionally flexibly mounted to the carry
on
machine, that is a swather tractor, combine harvester or pull type frame, and
the
header as one piece can generally follow the ground contour while the cutting
knife
remains rigid.
It is also known that headers of this type can be controlled so that they
rotate around an axis at a centre of the header in response to sensors which
detect
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3
ground height so as to maintain the sides of the header as close to the ground
as
possible.
When cutting above the ground a header of this type with a rigid knife
structure is most effective because the rigid knife structure allows maximum
cutting
speed and thus an improved cutting action.
When cutting on the ground with larger headers, it is known to have a
cutter bar which is mounted on the header so that it can flex or float across
its width
relative to the ground. Examples of such flexible cutter bars are shown in
U.S.
Patents 4,665,685 (Rupprecht) issued May 19, 1987 and 4,875,331 (Ostrup)
issued
October 24, 1989. Both of these arrangements show a cutter bar which is
mounted
on a skid and thus skids across the ground and flexes across its whole width
to
accommodate changes in height of the ground.
One significant disadvantage of the conventional flexible cutter bar is
that it requires a significantly reduced cutting speed since the reciprocation
of the
conventional sickle knife must be reduced in velocity to accommodate the
curvature
of the cutter blade which can occur when the whole of the cutter blade is
flexible.
Conventionally a flexible cutter bar of this type can flex as much as eight
inches in
each direction to accommodate the changes in ground height which occur
relative to
the fixed part of the header frame which remains fixed and does not change
relative
to ground height.
A further disadvantage of a flexible cutter bar of this type is that it is
necessary to set the reel at a height which accommodates the upward movement
of
the cutter bar which can occur. The reel fingers therefore must necessarily be
spaced a significant distance from the cutter bar to avoid the possibility
that the
raised cutter bar interferes with the fingers and causes damage to either or
both.
This increased distance between the fingers of the reel and the cutter bar can
cause
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4
irregular or improper feed of the crop material over the cutter bar
particularly in light
crop conditions so that an accumulation of cut crop on the cutter bar can
eventually
halt further cutting action leaving a part of the crop uncut and thus
unharvested.
The disadvantage of the rigid cutter bar design is that rather than
floating over a small area like a ridge or gopher mound, the rigid header
pushes dirt
in front of the sickle knife which impedes cutting and allows dirt to enter
the header
with the crop.
Up till now, therefore, neither the rigid header arrangement with its
improved cutter speed and accurate reel location is fully satisfactory nor is
the
flexible cutter bar design in view of the reduced cutter speed and the
increased
space between the reel fingers and the cutter bar.
SUMMARY OF THE INVENTION
It is one object of the present invention to provide an improved header
which allows flexible movement of the cutter bar but overcomes some or all of
the
above stated disadvantages.
According to a first aspect of the invention there is provided a crop
harvesting header comprising:
a main frame structure extending across a width of the header for
movement in a direction generally at right angles to the width across ground
including a crop to be harvested;
a mounting assembly for carrying the main frame structure on a
propulsion vehicle, the mounting assembly being arranged to provide upward and
downward movement of the main frame structure relative to the ground and
including upward and downward movement of each end independently of the other
end;
a crop receiving table carried on the main frame structure across the
CA 02307176 2000-04-27
width of the header;
a flexible cutter bar across a front of the table carrying a cutter knife
operable for cutting the crop as the header is moved forwardly across the
ground for
depositing the crop onto the table;
5 the table including a crop transport system on the table for moving the
cut crop toward a discharge location of the header;
a plurality of support arms arranged at spaced positions across the
width of the main frame structure and each arm extending forwardly from the
main
frame structure underneath the table for supporting the table and the cutter
bar;
the support arms including two outer support arms arranged at outer
ends of the main support frame for supporting ends of the cutter bar;
the support arms including at least one inner support arm spaced
between the outer support arms for supporting an intermediate portion of the
cutter
bar;
the outer support arms being fixed rigid members rigidly connected to
the main frame structure and to the ends of the cutter bar so as to hold the
ends of
the cutter bar at a height determined by the main frame structure;
the at least one inner support arm being arranged to allow flexible
movement upwardly and downwardly of a front portion thereof attached to the
cutter
bar such that a center portion of the cutter bar between the ends of the
cutter bar is
free to move upwardly and downwardly in response to forces thereon.
Preferably the support arm includes a float arrangement supporting at
least a part of the weight applied to the front portion such that the cutter
bar is free to
float upwardly in response to force thereon less than the weight.
Preferably the float arrangement carries almost all of the weight of the
cutter bar and the other elements at the front of the table so that the
floating action
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requires little forces from engagement with the ground.
The float arrangement can be provided by springs within the table
support arm or arms or by other arrangements know to one skilled in the art.
However in one particularly described arrangement herein, the float
arrangement is
provided by a counterbalance system in which the support arm includes a rear
portion projecting forwardly from the main frame structure with the front
portion
mounted on the rear portion at a pivot for pivotal movement relative thereto
about an
axis across the width of the header such that upward and downward pivotal
movement of the cutter bar is provided by said pivotal movement of the front
portion
and wherein the float arrangement is provided by a mounting arm carried on the
mounting assembly and supporting the rear portion of the arm rearwardly of the
pivot
and providing a fulcrum supporting the front portion forwardly of the pivot,
with the
position of the fulcrum arranged to substantially balance the weight applied
to the
front portion forward of the fulcrum by the cutter bar relative to the weight
applied
from the rear portion to the front portion at the pivot such that the front
portion floats
about the fulcrum.
Preferably the mounting arm is pivotally connected to the rear portion
at a rear end of the rear portion for pivotal movement about an axis across
the width.
Preferably the mounting assembly includes the conventional forwardly
extending lift arm which engages and applies lifting force to the mounting
arm.
Preferably the distance of upward and downward movement from a
straight line between the fixed ends of the cutter bar is limited by a
mechanical
linkage to a distance considerably less than that of conventional flexible
cutter bars.
As set forth above, less movement relative to the main frame structure is
required as
the main frame is flexibly mounted to the propulsion vehicle allowing the ends
of the
header to follow the ground. The amount of movement is preferably less than a
total
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7
of 5 inches and most preferably of the order of four inches.
Preferably the transport system of the table comprises a draper with a
mounting rollers of the draper having a front end arranged such that weight
therefrom is applied to the front portion of the at least one inner support
arm.
However the flex system can also be used with auger type headers
where the auger is mounted at the rear of the table and remains fixed to the
fixed
outer support arms. Thus the auger remains fixed and straight while the cutter
knife
and a forward bridging part of the table flex.
Preferably the transport system of the table comprises a pair of
drapers each arranged to carry the cut crop to a central discharge location
and
wherein there is provided two inner support arms each arranged on a respective
side of the central discharge opening.
Preferably there are four support arms at spaced positions between
the end rigid arms.
Preferably the cutter bar includes a substantially rigid portion at each
end, each rigid portion being rigidly attached to a respective one of the
outer support
arms such that the rigid portion is maintained at an orientation fixed by the
main
frame and the outer support arms and such that upward and downward movement
of the cutter bar is limited to a portion of the cutter bar between the rigid
end
portions.
Preferably the knife comprises a sickle knife mounted for reciprocating
movement longitudinally of the cutter bar and the knife drive for the sickle
knife is
rigidly mounted on one of the outer support arms for a single knife drive or
on both of
the outer support arms for a double knife drive and wherein the knife drive is
rigidly
mounted on the outer support arm such that the knife drive is fixed relative
to the
rigid end portion of the cutter bar.
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In most embodiments, the header includes a reel having a reel hub
mounted above the cutter bar for rotation about an axis across the width of
the
header such that fingers of the reel are arranged to sweep over the cutter bar
as the
reel rotates. The reel includes two end mounting arms each extending forwardly
from the main frame structure to the hub at a respective end of the reel.
In wider headers such as those greater than 30 feet, the reel also
includes preferably, together with the necessary two end mounting arms, at
least
one additional inner mounting arm extending forwardly from the main frame
structure
to the hub. In such arrangements, the embodiment preferably includes means for
moving the reel hub upwardly and downwardly at the inner or center mounting
arm
in response to said upward and downward flexing movement of the cutter bar.
The smaller headers less than 30 feet could have the flexible cutter bar
with limited vertical movement as set forth above. Because the ends of the
cutter bar
do not move relative to the frame, the reel can be located close to the cutter
bar at
the ends and spaced away from the cutter bar at the centre thus forming an
hour
glass shaped reel. The limited vertical cutter bar movement would allow the
reel to
be located substantially closer to the cutter bar than conventional flex
headers.
The moving means for effecting the moving of the reel in response to
the flexing of the cutter bar can be provided by many different arrangements
including a mechanical linkage or optical detector which detects the changes
in
height of the cutter bar and operates a hydraulic cylinder or other linkage
for
mechanically raising the header at the center position. However, in a
particularly
simple arrangement which is preferred, the moving means comprises a simple
strut
between the cutter bar and the reel at a position spaced inwardly of the ends.
Preferably the strut is extendable to allow the reel to be raised away
from the cutter bar.
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9
Preferably the reel includes a central support arm and wherein there is
provided a single link between the center of the cutter bar and the central
support
arm.
According to a second aspect of the invention there is provided a crop
harvesting header comprising:
a main frame structure extending across a width of the header for
movement in a direction generally at right angles to the width across ground
including a crop to be harvested;
a mounting assembly for carrying the main frame structure on a
propulsion vehicle;
a crop receiving table carried on the main frame structure across the
width of the header;
a flexible cutter bar across a front of the table carrying a cutter knife
operable for cutting the crop as the header is moved forwardly across the
ground for
depositing the crop onto the table;
the table including a crop transport system on the table for moving the
cut crop toward a discharge location of the header;
a plurality of support arms arranged at spaced positions across the
width of the main frame structure and each arm extending forwardly from the
main
frame structure underneath the table for supporting the table and the cutter
bar;
at least one of the support arms being arranged to allow flexible
movement upwardly and downwardly of a front portion thereof attached to the
cutter
bar such that a center portion of the cutter bar between the ends of the
cutter bar is
free to move upwardly and downwardly in response to forces thereon;
wherein the at least one support arm includes a rear portion projecting
forwardly from the main frame structure with the front portion mounted on the
rear
CA 02307176 2000-04-27
portion at a pivot for pivotal movement relative thereto about an axis across
the
width of the header such that upward and downward pivotal movement of the
cutter
bar is provided by said pivotal movement of the front portion and wherein the
float
arrangement is provided by a mounting arm carried on the mounting assembly and
5 supporting the rear portion of the arm rearwardly of the pivot and providing
a fulcrum
supporting the front portion forwardly of the pivot, with the position of the
fulcrum
arranged to substantially balance the weight applied to the front portion
forward of
the fulcrum by the cutter bar relative to the weight applied from the rear
portion to
the front portion at the pivot such that the front portion floats about the
fulcrum.
10 According to a third aspect of the invention there is provided a crop
harvesting header comprising:
a main frame structure extending across a width of the header for
movement in a direction generally at right angles to the width across ground
including a crop to be harvested;
a mounting assembly for carrying the main frame structure on a
propulsion vehicle;
a crop receiving table carried on the main frame structure across the
width of the header;
a flexible cutter bar across a front of the table carrying a cutter knife
operable for cutting the crop as the header is moved forwardly across the
ground for
depositing the crop onto the table;
the table including a crop transport system on the table for moving the
cut crop toward a discharge location of the header;
a plurality of support arms arranged at spaced positions across the
width of the main frame structure and each arm extending forwardly from the
main
frame structure underneath the table for supporting the table and the cutter
bar;
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at least one inner support arm being arranged to allow flexible
movement upwardly and downwardly of a front portion thereof attached to the
cutter
bar such that at least a center portion of the cutter bar is free to move
upwardly and
downwardly in response to forces thereon;
a reel having a reel hub mounted above the cutter bar for rotation
about an axis across the width of the header such that fingers of the reel are
arranged to sweep over the cutter bar as the reel rotates, the reel including
two end
mounting arms and at least one inner mounting arm each extending forwardly
from
the main frame structure to the hub;
and means for moving the reel hub upwardly and downwardly at the
inner mounting arm in response to said upward and downward flexing movement of
the cutter bar.
BRIEF DESCRIPTION OF THE DRAWINGS
One embodiment of the invention will now be described in conjunction
with the accompanying drawings in which:
Figure 1 is a cross sectional view through a header according to the
present invention showing the construction of one of the flexible table
support arms.
Figure 2 is a cross sectional view similar to that of Figure 1 on a
smaller scale and showing the reel.
Figure 3 is a cross sectional view similar to that of Figure 1 showing
the flexing movement.
Figure 4 is a cross sectional view similar to that of Figure 1 showing
the support structure for allowing a float action of the rigid header frame
section on
the support vehicle.
Figure 5 is an isometric view showing the header frame only of a
header including the flexible arm of Figure 1.
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Figure 6 is a transverse cross sectional view along of the flexible table
support arm of Figure 1 taken along the lines 6-6 of Figure 4.
Figure 7 is a schematic front elevational view of a portion only of the
header showing the connection between the centre reel support arm and the
cutter
bar.
Figure 8 is a front elevational view of a scrap of the header at the
connection between the cutter bar and the fixed support arm
In the drawings like characters of reference indicate corresponding
parts in the different figures.
DETAILED DESCRIPTION
A header is shown in the figures and is arranged for attachment to a
crop harvesting machine for cutting standing crop and for carrying the cut
crop to a
position on the header where the cut crop can be discharged either into the
feeder
house of a combine harvester or to the ground for forming a swath. The header
may
be of a type which can be converted for use with either a combine harvester or
a
swather tractor or may be dedicated to one or other of these functions.
As described hereinafter, the header includes a cutter bar which can
be arranged so as to flex upwardly and downwardly over a limited distance so
that
the header can more closely follow the ground. Thus the header can be used to
run
directly over the ground surface for cutting substantially the whole of the
standing
crop. However, when the header is used for cutting the top part only of a
standing
crop, it may be desirable to lock the cutter bar straight. Where the header
runs
across the ground, the flexing action of the cutter bar will allow it to more
closely
follow the ground contour. In addition, the header is mounted for floating
action so
that each end of the header can be raised and lowered independently of the
other to
assist in the following of the ground contour.
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13
The header generally indicated at 10 comprises a frame 11, a cutter
bar 12 for cutting the standing crop, a pair of drapers 13 and 14 for carrying
the cut
crop to a central opening 15, and a reel structure 16 for sweeping the
standing crop
over the cutter bar 12 onto the drapers 13 and 14.
The frame 11 comprises a main beam 20 which extends the full width
of the header from a first end 20A to a second end 20B. The beam includes a
mounting assembly 21 by which it is attached to the harvesting vehicle. In the
embodiment shown the mounting assembly 21 comprises a simple lug 21A for
attachment to a link 22 of the transport vehicle.
The frame 11 further includes a plurality of table support arms 23A,
23B, 23C, 23D, 23E and 23F. These include two outer support arms 23A and 23F
arranged at the respective ends 20A and 20B of the beam 20. The support arms
23
and 23F are generally triangular in shape so that they are rigid and are
rigidly
attached to the beam 20. Thus each of the outer arms 23A, 23F includes an
inner
sheet 24 having a top edge 25 and a rear edge 26 defining an upper apex at
which
the beam 20 is welded to the arm. The bottom edge 27 converges with the top
edge
to a forward apex 28 at the cutter bar. The end support arms are stiffened by
top
and bottom flanges which project outwardly. Thus the outer support arms are
rigid
and maintain their position at right angles to the beam 20 with the front apex
28 at a
20 predetermined angular position relative to the axis of the beam 20. The
strength of
the beam and the end support arms is arranged so that there is little or no
flexing of
the structures.
The frame further includes the inner table support arms 23B, 23C, 23D
and 23E. In narrower headers, the additional arms 23B and 23E may be omitted.
25 The innermost arms 23C and 23D are located each on a respective side of the
central opening 15 arranged to co-operate with the feeder house of a combine
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14
harvester or arranged to allow discharge of the crop material. The drapers 13
and
14 are carried so that they extend from the respective end support arm to a
position
at the respective inner most support arm.
The drapers 13 and 14 include draper rollers 13 and a continuous
draper canvas wrapped around the rollers with a canvas having a front edge 32
at
the cutter bar 12 and a rear edge 33 underneath the beam 20. The details and
construction of the drapers is well known to one skilled in the art.
The cutter bar 12 comprises a plate 34 which is bent to define a flange
35 on which a plurality of knife guards 36 is mounted at positions across the
full
extent of the cutter bar. The cutter bar extends rearwardly from the flange 35
to
define a downturned inclined portion 37 and a rear generally horizontal
portion 38
which attaches to the respective support arm. The cutter bar is formed so that
it has
sufficient ability to flex upwardly and downwardly to allow movement of a
centre
section of the cutter bar upwardly and downwardly by a distance of the order
of 2
inches making a total amount of movement of the order of 4 inches. This amount
of
flexing can be tolerated in a continuous steel band without reaching the
elastic limit
so that there is no necessity for complex structures of the cutter bar.
However the
structure may be modified by the provision of flexing joints if necessary.
The cutter bar includes a stiffening section at each end which is rigidly
attached to the rigid end support arms. Thus the flange 38 as shown in Figure
8
includes a stiffening portion 38A on its underside which is welded to the
sheet 24 of
the end support arm 23F at the bottom flange 24A.
Thus the end portions of the cutter bar are maintained at right angles
to the sheet 24 and thus directly parallel to the axis of the main beam 20.
However
the centre section of the cutter bar can flex upwardly and downwardly as
indicated in
the dash lines at 12A and 12B. At the end it will be noted that the dash lines
lie
CA 02307176 2000-04-27
substantially coincident with the cutter bar itself since there is
substantially no flexing
movements at the ends with the amount of flexing movement gradually increasing
from zero at the ends to a maximum amount at the intermediate support arms
with
the amount of flexing being determined by a limited movement of each of the
5 support arms as described hereinafter.
Turning now to Figures 1 and 3, one of the inner support arms 23D is
shown extending from the cutter bar to the beam 20. The support arm 23D
comprises a rear portion 40 which extends downwardly in a first section 41 and
then
forwardly in a second section 42 to a forward end 43. The rear portion 40 is
formed
10 as a channel with a web section 44 and two rearwardly extending flanges 45,
one of
which is visible in Figures 1 and 3 and both of which are visible in Figure 5.
The web
45 thus defines a first substantially vertical section which extends
downwardly to an
apex 46. The web then forms a horizontal section 47 which extends from the
apex
to the forward end 43.
15 The arm further includes a front portion 48 which extends from a rear
end 49 to a forward apex 50 which is welded to the flange 38. The front
section 48
is again channel shaped with a top web 51 and two depending sides 52. The
depending sides 52 reduce in height from the rear end 49 where they are
substantially of a common height to the sides 45 of the rear portion toward
the apex
50. A skid plate 53 is welded across the sides 52 at the forward part thereof
so as to
form the apex area 50 into a closed section of increased strength and for
sliding over
the ground behind the flange 38.
A pair of transverse pivot pins 54 interconnect the side walls 52 and 45
for pivotal movement about an axis 55 of the pins 54. Thus the pins are
arranged at
a slight overlap between the front and rear sections of the support arm and
the pins
are arranged adjacent the top web 47. Thus as shown in Figure 3, the forward
CA 02307176 2000-04-27
16
portion can pivot upwardly and downwardly from a raised position indicated at
56 to
a lowered position indicated at 57 about an intermediate or straight position
between
the two. The two extremes of movement are shown in Figure 3 and the distance D
therebetween is a total of approximately 4 inches so that the cutter bar moves
upwardly from its initial straight position by a distance of 2 inches and
moves
downwardly also by a distance of two inches. This amount of movement is
controlled by a pin 58 carried on the side walls 45 and projecting through a
slot 59 in
the side walls 52. The pin 58 can be clamped in position to lock the arm
against
flexing movement thus holding the cutter bar straight.
This arrangement is shown in cross section in Figure 6 where it will be
noted that the channel forming the front portion 48 is arranged outside the
channel
forming the bottom of the rear portion 40 and spaced therefrom sufficiently to
allow
the pivotal action set forth above.
Thus each of the inner support arms can allow this pivotal movement
of the cutter bar upwardly and downwardly by the limited movement defined by
the
pivot pin 54 and the limit pin 58. The pivotal movement is accommodated by
slight
twisting of the draper 14 and by lifting of the draper rollers. A guide plate
60 extends
from the cutter bar upwardly and rearwardly over the top of the front edge of
the
draper and this guide plate also moves upwardly and downwardly with the cutter
bar
and therefore remains in its position relative to the draper.
The rear edge of the draper is covered by a cover plate 61 which forms
part of a rear plate 62 of the header mounted across the header in front of
the web
portions 44 of the support arms. The cover sheet 62 is fastened at a top
fastener 63
and depends downwardly to a bottom edge 64 lying on top of the rear portion of
the
arm at the web 47. The sheet acts as a hanger for the rear end of the draper
roller.
The pivotal action of the front portion of the inner support arms is
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17
supported to allow a floating action of the cutter bar thus acting to carry
the majority
of the weight of the cutter bar and the forward portion of the arms so that
little force
is required to lift the cutter bar from its normal straight position and the
cutter bar can
droop to the ground level should the ground level fall away from the cutter
bar.
The floating action can be provided by springs within the support arm
in an arrangement which will be apparent to one skilled in the art.
However in order to avoid the provision of springs in an area where
they may become contaminated by soil of other debris, the device as shown uses
a
counter balance arrangement for providing the float action. The counter
balance
arrangement is shown in Figures 4 and 6. For convenience of illustration the
counter balance arrangement is omitted from the remaining figures.
The counter balance arrangements comprises a beam 70 which is
formed as a channel within the bottom channel of the rear portion of the arm.
The
channel 70 has a web 71 just underneath the web 47. The beam 70 is pivotally
mounted relative to the rear portion of the support arm on a pin 72 at the
rear end of
the beam and located at the apex 46. The beam extends forwardly from the pivot
72
through the intersection between the front and rear portions of the arm at the
pivot
pins 54 to a forward end 73 spaced forwardly of the pivot pins 54 and within
the front
portion 48. The top web 71 of the beam 70 carries a second pivot 75 which
projects
upwardly from the top web 71 into abutment with the web 51 of the front
portion 48
at a position spaced forwardly of the pivot pins 54 and the corresponding
pivot axis
55. The pivot 75 is provided by an abutment on one of the webs 51 and 71 so as
to
provide a fulcrum which allows a pivoting action on top of the beam 70 by the
front
portion 48.
The beam 70 is supported by one of a pair of spring arms 76 forming
the coupling of the header to the transport vehicle. Thus the transport
vehicle
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18
comprises a support structure 77 which can be the front of the feeder house of
a
combine harvester or can be a suitable strut on a swather structure and that
structure 77 carries the link 22 previously described at the centre of the
header and
the pair of lift arms 76.
In the embodiment shown the lift arms are formed as leaf springs but
other arrangements are well known in the industry which provide lifting
support to
the header at the inner support arms 23C and 23D. The leaf springs are the
simplest arrangement and are therefore shown for convenience but other
arrangements include rigid arms mounted on suitable tension springs. Yet
further,
other arrangements can include rigid arms which are actuated by a hydraulic
lift
system so that instead of floating on a simple spring arrangement, the header
can
be raised and lowered by operation of a hydraulic cylinder.
The leaf spring 76 as shown extends to a position forward of the pivot
72 so that in combination with the link 22 the leaf spring 76 act to lift or
support the
header in movement across the ground. The fulcrum 75 provides a counter
balance
for the front portion of the arm. Thus the weight of the header is applied
through the
pivot pins 54 onto the rear end of the front portion 48 and the weight of the
cutter bar
and the forward end of the support arms including the forward end of the
drapers is
carried at the cutter bar forwardly of the fulcrum 75. The header is of course
significantly heavier in weight than the forward parts carried on the cutter
bar and
therefore the fulcrum is located closely adjacent the pins 54. However the
location
of the fulcrum 75 is selected so that the weight is closely balanced thus
carrying the
weight at the cutter bar in a balanced condition on the fulcrum 75 allowing a
small
force from contact with the ground to raise the cutter bar and allowing the
cutter bar
to droop in the event that it is not supported by the ground. Thus the pivotal
action
of the front portion occurs about the pins 54 but the fulcrum 75 provides a
lifting
CA 02307176 2000-04-27
19
action on the front portion of the arms with sufficient force to balance the
weight of
the cutter bar and its associated elements.
The three point lifting action of the harvesting vehicle on the header
provided by the link 22 and the springs 76 allows the header to float so that
its
weight is carried substantially wholly on the springs 76 thus allowing it to
drop into
contact with the ground slightly under its own weight but to be lifted
upwardly on
engagement with the ground in a floating action. The three point arrangement
also
allows each end to independently float upwardly so that the ground contour
changes
so that one end is higher than the other, the engagement of the ground of that
end of
the header acts to lift that end of the header while the other end of the
header drops.
This floating action of the whole of the header together with the slight
flexing action of the center part of the cutter bar allows the cutter bar to
closely follow
the ground, even though the amount of movement of the cutter bar is relatively
small
as described before.
The cutter bar 12 carrying the knife guards 36 locates a sickle knife 80
of conventional construction including an elongate knife bar and a plurality
of knife
elements all of which are known to one skilled in the art. The knife bar is
driven in
reciprocating action by a sickle knife drive assembly 81 carried on the end
support
arm. In some headers there is provided only a single sickle knife drive
mounted on
one of the fixed support arms. In other headers to provide a more balanced
action
and to reduce loads on the knife bar and on the drive, the knife is divided in
two
halves each driven from a respective end so that there are two drives 81 and
82 on
the respective end support arms. The construction of the drive assembly is
well
known to one skilled in the art and therefore will not be explained in detail
herein.
The drive assembly is however mounted rigidly on the support arm so that it is
fixed
at the sheet 24 as shown in Figure 8.
CA 02307176 2000-04-27
The fact that the cutter bar 38 is maintained directly at right angles to
the end sheet 24 and also the knife bar drive assembly 81 is also mounted
directly
and rigidly on the end sheet 24 allows the knife bar drive assembly to operate
at the
conventional high speed which is used on rigid type headers. There is no need
for
5 any flexing or hinging of the construction and the knife bar simply moves in
a straight
line directly away from and toward the drive assembly 81. Furthermore the
drive
assembly 81 can be driven by a pulley 82 which remains in a plane parallel to
the
sheet 24 and therefore again there is no twisting of the drive connection from
a drive
assembly at the beam 20 through to the knife bar itself since all of these
10 components remain in their fixed orientation without twisting or flexing.
The only
flexing action therefore occurs at a position spaced inwardly from the end
support
arms and this can be accommodated by the flexing of the cutter bar as
previously
described and the flexing of the knife bar while the knife bar is properly
guided within
the knife guards so that the whole of the knife structure can operate at the
15 conventional high speeds attainable by rigid type headers.
Turning now to Figures 2 and 7, the reel 16 comprises a reel hub 90
carried on arms 91 extending from the beam 20. The reel hub 90 carries a
plurality
of reel fingers 92 which sweep over the knife to carry the crop during the
cutting
action over the knife and onto the table. The construction of the reel is
generally
20 conventional and therefore the details of the reel will not be described
herein as they
are well known to one skilled in the art. Various arrangements for the
construction
and drive of the reel fingers are available and the present invention is not
limited to
specific types of reel or specific types of reel fingers.
In narrower width headers, the reel is simply mounted on two reel arms
each at a respective end of the beam and each at a height which can be fixed
relative to the ends of the knife so that the distance of the reel fingers
from the knife
CA 02307176 2000-04-27
21
is determined at the ends. In such narrower width headers therefore, the
flexing of
the cutter bar acts to slightly change the distance between the reel fingers
and the
knife at the centre section of the cutter bar.
However in wider width headers it is desirable also to adjust the height
of the reel to accommodate and compensate for the flexing of the cutter bar as
described herein before. In such an arrangement, therefore, the reel is
carried on
two end arms, (not shown) together with a centre arm 91 which is carried on a
pivot
pin 92 on the beam 20. The beam 20 further includes a forwardly extending
bracket
94 connected to a hydraulic cylinder 95 which raises and lowers the arm. All
three
arms can therefore be raised to lift the reel away from the knife when the
reel is not
required. In addition the central arm only can float upwardly and downwardly
by a
distance substantially equal to the flexing movement of the knife to allow the
center
part of the hub to move upwardly and downwardly. This movement is provided
with
a floating action by a floatation spring 96. The reel lift cylinder is
attached to the reel
support arm through a spring loaded bell crank 95A. Normally the cylinder
would act
directly onto the arm. The bell crank can pivot on a pin through the reel
support arm
by the force of the spring. It would be simpler to put a compression spring on
the end
of the cylinder. However, because the spring force is proportional to the
spring
deflection, the spring force on the cylinder would change as the reel is
floated. The
bell crank is arranged to increase the moment arm for the spring as the spring
relaxes, thus exerting a substantially constant moment on the bell crank, and
therefore a constant force on the cylinder. The reel can then be floated with
a
constant force.
The hub at the centre arm is then moved upwardly and downwardly in
response to the movement of the cutter bar. This is achieved in a simple
technique
by providing a strut 97 which is connected at its lower end to the cutter bar
and is
CA 02307176 2000-04-27
22
connected at its upper end to the floating center arm 91. Thus the movement of
the
cutter bar is directly followed by the movement of the centre arm of the reel
simply
by pulling and pushing on the strut 97. As the majority of the weight of the
reel is
carried on the floating system provided by the spring 96, the movement of the
cutter
bar is not inhibited by this additional necessary movement of the reel. The
weight of
the reel therefore is carried and it is only necessary to overcome the inertia
of the
reel to effect the floating action of the cutter bar.
The control of the height of the reel therefore relative to the cutter bar
maintains the fingers of the reel at the required location or height relative
to the knife
to provide the best finger action. It will be appreciated that in the absence
of this
floating action it is necessary to set the fingers relative to the highest
point of the
cutter bar rather than the normal height of the cutter bar since it is not
acceptable to
allow the fingers to engage into the knife with consequential damage to both
components.
The floating action set forth above provides the simplest connection to
hold the reel at the required height. However alternative techniques are
available in
which the position or height of the cutter bar is measured by mechanical
linkage or
by optical techniques and the position of the centre arm of the reel is
adjusted by
actuating the cylinder 95 to effect controlled movement of the height of the
reel in
dependence upon the measured height of the cutter bar.
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 departing 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.
