Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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PRIOR ART STATEMENT
Heretofore, others have attempted to reduce lateral
vibration in a mower by using two aligned sickle bars. For
instance U.S. patent 3,508,388 illustrates such an attempt
wherein the guard at the inboard ends of the sickle bars
carries an oversized ledger plate. This prior art design is
believed to not be satisfactory because the inboard edges of
the inboard sickle knives do not have sharpened edges and hence
do not act as totally effective cutting elements in the inboard
stroke of the sickle bars. In the double sickle bar arrange-
ment of U.S. patent 3,577,716, one sickle bar is displaced
vertically the thickness of a knife element and special shims
are used to adjust the height of the other sickle bar. ln this
last mentioned patent an overlapping sickle bar extension
carrying conventional knife elements on its underside is
secured to one sickle bar and the inboard end of the other
sickle bar carries an inverted knife element which cooperates
with knife elements on the overlapping extension sickle bar to
cut crop in the overlapping area of the two sickle bars.
STATEMENT OF THE INVENTION
This invention provides a mowing device for cutting a
standing crop which includes a stationary cutter bar secured to
a mobile frame and extending transversely therealong. A
plurality of substantially uniform length standard knife guards
are mounted in transverse alignment on the cutter bar and
project forwardly thereform, each of the standard guards having
an upward facing horizontal ledger surface terminating in first
and second shearing edges at its transversely opposite ends.
First and second conversely reciprocating sickle bars are
disposed in generally parallel relation to and forwardly of the
cutter bar and are in transverse alignment with their inboard
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ends terminating in spaced apart relationship at a midportion
of the cutter bar. Knife elements are mounted on the upper
surface of the sickle bars and cooperable with the first and
second shearing edges of the standard guards for the cutting
crop. An extension bar is mounted on top of one of the cutter
bars adjacent its inboard end and has a portion extending in
overlying relation to the inboard end part of the other cutter
bar. Inverted knife elements are mounted on the bottom surface
of the extension bar in overlying relation to the transverse
space between the first and second cutter bars. A plurality of
special knife guards are mounted on the midportion of the - -
cutter bar in transverse alignment with each other and with the
standard guards and project forwardly from the cutter bar.
Each of the special knife guards has upper and lower vertically
spaced horizontal ledger surfaces terminating in shearing edges
at transversely opposite sides thereof, with the upper ledger
surfaces cooperating with the inverted knife elements to cut
crop in the space between the inboard ends of the first and
second cutter bars.
This invention provides an improved reciprocating
sickle bar type cutter for agricultural crops which is suitable
for large-capacity, high-speed harvesting equipment. More
specifically the cutter or mower includes two reciprocating
; sickle bars which are in end-to-end alignment, but not
connected directly to one another. An extension bar is secured
to one of the sickle bars and carries inverted knife elements
which cooperate with upper shear edges on the guards disposed
in the area of the inboard ends of the sickle bars.
It is an object of the present invention to provide a
cutting mechanism which is of great length and which can be
operated satisfactorily at relating high speed.
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It is a further object of this invention to provide a
dual sickle bar cutter mechanism wherein the sickle bars are in
alignment and have adjacent but spaced inboard ends at the
central part of the header or cutting unit.
It is a further object of the present invention to
provide a cutter having two separately driven sickle bars with
an extension on one sickle bar overlapping the end of the other
sickle bar and carrying inverted knives coacting with upper
shear edges on associated guards to shear the crop in the gap
between the inboard ends of the sickle bars.
These and other objects and advantages of the present
invention will be apparent to those familiar with the art when
the following description is read in conjunction with the
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
One embodiment of the present invention is shown in
the drawings in which:
Fig. 1 is a top view of a header for a combine with
parts broken away for illustration purposes;
Fig. 2 is an enlarged front view of the central
portion of the cutting mechanism of the header shown in Fig. 1
and showing the inboard ends of the dual sickle bars in the
laterally outer position of their reciprocating strokes;
Fig. 3 is a view similar to Fig. 2 but showing the
inboard ends of the reciprocating sickle bars at an inter-
mediate position between their laterally outer and laterally
inner positions;
Fig. 4 is a view similar to Figs. 2 and 3 but showing
the inboard ends of the sickle bars in their laterally inner
positions;
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Fig. 5 is an enlarged partial top view of the cutting
mechanism taken along the line V-V in Fig. 4, showing the
inboard ends of the sickle bars and an overlying extension;
Fig. 6. is a section view taken along the line VI-VI
in Fig. 5;
Fig. 7 is a section view taken along the line VII-VII
in Fig. 5;
Fig. 8 is a section view taken along the line
VIII-VIII in Fig. 7; and
Fig. 9 is a section view taken along the line IX-IX
in Fig. 3.
DETAILED DESCRIPTION O THE DRAWINGS
Referring to Fig. 1, the present invention is shown
- incorporated in a crop header 11 for combine which is suitable
for cutting small grain. The header 11 includes an auger
mechanism 12 which includes oppositely pitched flights 13, 14
which serve to convey the cut crop laterally inward to a
central part of the header from whence the cut crop is conveyed
rearwardly and upwardly to the threashing mechanism by the
conveying apparatus, not shown. The standing crop of ripened
grain is severed by a cutting mechanism 16 which includes a
transversely extending, stationary cutter bar 21 which is
rigidly secured to the front end of a frame 15 of the header
11. A plurality of substantially uniform length, standard
knife guards 22 are mounted in transverse alignment on the
cutter bar 21, as illustràted in Fig. 9, by bolts 23 and nuts
24 so as to-project forwardly from the cutter bar. Special
knife guards 26 mounted on the central portion of the cutter
bar 21 are of novel construction as will hereinafter be
described.
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A pair of sickle bars 31, 32 are disposed in
generally parallel relation to and forwardly of the cutter bar
21. The sickle bars 31, 32 are in end-to-end transverse
alignment and have their outboard ends pivotally connected to
levers 33, 34, respectively, which are pivotally mounted to
brackets 36, 37 on the frame 15 of the header 11. The sickle
bars 31, 32 are caused to conversely reciprocate by rods 38, 39
connected at their forward ends to levers 33, 34 and at their
rear ends to crank arms 41, 42 secured to aligned drive shafts
10 43, 44. The drive shafts 43, 44 carry sprockets 46f 47 at
their inboard ends which are driven by a pair of drive chains
48, 49. The drive chains 48, 49 are drivingly carried on a
pair of sprockets 51, 52 secured to the outboard ends of a
; drive shaft 53 which is driven by the combine engine, not
shown, through a drive train which includes a drive belt 54
engaging a pulley 56 on the drive shaft 53. In the condition
of the cutting mechanism shown in Figs. 1 and 2, the sickle
bars 31, 32 are in their laterally outer positions of
reciprocation. When the drive shafts 43, 44 are simultaneously
rotated 180 degrees, the sickle bars will be moved to their
laterally innermost position as illustrated in Fig. 4. Fig. 3
illustrates an intermediate position of reciprocation which is
between the laterally outer and the laterally inner positions
of the sickle bars.
Rnife elements 56, are mounted on the upper surfaces
116, 117 of the sickle bars 31, 32 and are secured thereto by
rivets 57. The knife elements 56 are of a generally triangular
shape and have a pair of forwardly converging cutting edges 59,
61 at the junction of the bottom surface of the knife element
and a pair of sloping edge surfaces 62, 63. The cutting edges
59, 61 on the knife elements 56 cooperate with the shearing
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edges 64, 65 sn the knife guards 22, to sever a standing crop
as the combine is driven through the field. The shearing edges
64, 65 are at the transversely opposite ends of an upward
facing horizontal ledger surface 70 on each of the standard
knife guards 22. -
The inboard ends 68, 69 of the sickle bars 31, 32 are
spaced from one another thereby leaving a gap between the
inboard ends. The gap varies from a distance approximately
equal to the spacing of one knife element, as illustrated in
Fig. 4, to a distance approximately equal to the spacing of
three knife elements. In order to cut the crop in the area of
the gap, an extension bar 71 is secured to sickle bar 32 by a
plurality of rivets 72. A spacer 73 of the same thickness as
the knife element 56 is placed between the extension bar 71 and
the knife elements 56 on sickle bar 32 thereby spacing the
underside surface 74 of the extension bar vertically above the
upper surface 75 of the knife elements 56 a distance equal to
the vertical thickness of inverted knife elements 103 secured
to the extension bar 71. The inverted knife elements 103,
which are of the same construction as knife elements 56, are
secured to the extension bar 71 by rivets 76. The extension
bar 71 extends laterally inward from the inboard end 69 of the
sickle bar 32 acros$ the gap between the inboard ends 68, 69 of
the sickle bars 31, 32 and in overlying relation to the inboard
end 68 of sickle bar 31. A slide member 79, which is secured
to the extension bar 71 by rivets 80, is in sliding engagement
with the top surface of the knife elements 56 secured to the
inboard end of sickle bar 31. The slide member 79 and spacer
73 are not only of the same vertical thickness as the knife
element 56 but are also of the same width as the extension bar
71 and sickle bars 31, 32, as illustrated in Figs. 8 and 9.
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The special knife guards 26, which are transversely
aligned with each other and with the standard guards 22, are
constructed with two ledger surfaces 81, 82 which are in
confronting, vertically spaced relation to one another. Ledger
surface 81 is upward facing and terminates in cutting edges 84,
85 at its transversely opposite sides which cooperate with the
cutting edges 59, 61 of the knife element 56. The ledger
surface 82 is downwardly facing and terminates in cutting edges
86, 87 at its transversely opposite ends. The cutting edges
86, 87 of the special knife guards 26 cooperate with cutting
edges 101, 102 on the inverted knife elements 103 to cut crop
in the area of the gap between the inboard ends 68, 69 of
sickle bars 31, 32. The special knife guards 26 are secured to
the cutter bar 21 by bolts 104, 104' and nuts 106.
As is customary in the trade, the transversely
aligned knife guards 22, 26 are forged in sets of two with an
integral transverse bridge. The bridge for knife guards 22 is
indicated by the reference character 111 and the bridge for the
special knife guards 26 is indicated by the number 112. A
plurality of hold down clips 113 are secured to the cutter bar
21 at laterally spaced intervals therealong.
SUMMARY
As the horizontlly aligned sickle bars 31, 32 are
conversely reciprocated by the illustrated drive mechanism,
their inboard ends 68, 69 move transversely toward and away
from one another but are always spaced from one another. The
cutting edges 101, 102 of the three inverted knife elements
103, which are identical in construction to knife elements 56,
cooperate with the shearing edges 86, 87 of the four special
knife guards 26 to cut standing grain or crop in the space
between the confronting inboard ends 68, 69 of the sickle bars
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31, 32. The sickle bars 31, 32 are in alignment with their top
surfaces 116, 117 lying in the same plane. This simplifies the
construction of the cutting mechanism 16, as compared with
prior art dual sickle cutting mechanisms wherein one sickle bar
is displaced vertically relative to the other. The extension
bar 71 is spaced above the sickle bars 31, 32 a distance equal
to the combined thickness of a knife element 56 and a knife
element 103. In order to properly accommodate the double -
thickness of knife elements in the central gap area the
10 parallel lower and upper horizontal ledger surfaces 81, 82 are ~.
vertically spaced from one another, a distance slightly greater
than the combined thickness of a knife element 56 and a knife
element 103. The slightly greater distance is necessary to
insure a relatively free sliding relationship between the :
ledger surfaces 81, 82 of the special guards 26 and the
~associated knife elements 56, 103.
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