Note: Descriptions are shown in the official language in which they were submitted.
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SICKLE CUTTING SYSTEM
Field Of The Invention
This invention relates to a sickle cutting system for use in agriculture
combines, swathers, mowers and the like.
Background Of The Invention
Reciprocating sickle systems have been commonly used in agriculture
harvesting equipment, such as in mowers, combine headers, and the like
for many years. Such systems in the main include a knife assembly formed
by at least one sickle bar to which are affixed a series of knives adapted to
io reciprocate within a corresponding series of forwardly projecting
stationary
guards for shearing the standing crop. For the sake of increasing the
cutting ability and particularly the rate of harvesting, such equipment has
experienced over the years the continual increasing of the width of the
header and of the ground speed of forward travel. As well combine units
have been enlarged within to increase the threshing operating capacity.
Accordingly, the lengths of cutter bars have been increased to
accommodate a wider swath and/or the frequency of the reciprocation of
the cutter bar has been increased so as to allow an increased speed of
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travel, thus improving the overall capacity of combine unit. In some cases a
system consisting of more than one cutter bar, arranged end-to-end, is now
used in view of the increased width.
The common form of drive for the sickle bar arrangement involves
the transferring of reciprocating forces which are generated by a
mechanism, such as a wobble box, to the bar by way of an attachment at
one end of the bar. The forces applied by such mechanism in the simple
reciprocating drive of the bars and its associated knives result in the bar
and the attachment being subjected to alternating compression and
lo tension forces many hundreds of time per minute. As will be described
further below the total forces within the bar at any one instant are the
addition and/or subtraction of a number of forces experienced by the bar
along its length at any one particular instant.
Considering an individual reciprocating cycle of the cutter bar of the
most common used design now in use, the more severe forces experienced
by the sickle bar occur, of course, at or near the bar attachment to the
drive system, normally located at one end of the bar. Determination of the
total load and its nature on the sickle bar experienced at the connecting
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end is complex. The total of the pull and push forces at the attachment end
are the addition of various tensile or compression load forces. The
individual cutting loads transferred to the sickle bar by the plant shearing
action on the knives with the guard member cause a compression in the bar
as it is moved outwardly relative to its connecting end and a tension in the
bar as it is drawn towards the bar connecting end, these individual load
forces accumulating along the sickle bar to a maximum total at the
connecting end. Superimposed on this is the alternating compression and
tension forces which occur during the application of forces by the drive to
overcome inertia for rapid acceleration of the sickle bar applied as the
sickle bar is forced in its outward stroke followed by forces of rapid
deceleration as it approaches its outmost point of the stroke. These
conditions are then followed by the tensile forces applied to the bar for the
accelerations of the sickle bar in its return stroke, such forces being added
to the resistance caused by the frictional and shearing forces required by
the cutting of the plants during the return stroke. This is then followed by
the effect of input of inertia forces in the slowing the speed to a stop at
the
end of the return stroke which is again super-imposed on the tension forces
caused by cutting and friction forces.
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Clearly, while the current use of a wobble box in the drive system has
provided a better pattern in the motion of the blade, the subjecting of the
sickle bar to rapid reversal between high compression and tensile forces
hundreds of times a minute, particularly at its drive end, is a cause of metal
failure. It has also been observed from the location of the breaks in the
sickle bar, that there are occurring effects other than just the size and
rapidity of change between high compression and tension forces within the
metal of the longer sickle bar in use. One such effect appears to be that of
very slight, undetectable buckling of the sickle bar which occurs under the
lo conditions now experienced by that part.
With the increased length, and/or higher knife reciprocating speed,
the life of the cutter bar has been reduced in spite of improved metal and
design characteristics and has also worsened the vibration problems within
the header.
On the other hand in the use of more than one sickle bar arranged
end-to-end, which is an alternative to one very long sickle bar now in use,
there is the additional cost in construction to synchronize the travel of the
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knives to avoid unacceptable vibration and resulting damage to the overall
equipment
Many attempts have been made to provide a better balanced system
in order to reduce the vibrations set up by the reciprocating knife and its
respective drive mechanism, but some have suffered due to the added
complexity of the system and to the fact that considerable damaging
vibration still exists.
Another process which has been developed to remove the vibration
disadvantages and sickle bar deterioration involves the replacing of the
1o reciprocating knife with an endless chain member which carries the knife
blades and travels in one direction about a pair of spaced sprockets, thus
providing a forward run of the chain moving through spaced guards.
Attempts to refine this latter concept to the point of being an acceptable
alternative have not been entirely satisfactory in that, for example, under
certain conditions there is experienced a frequent jamming of vegetation
in guards due to the continued passage of the knife blades in the same
direction through the guards.
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In addition to the sickle bar failure problems described above, the
use of the longer sickle bar and increased sickle speed require that an
enlarged drive unit must be used and this has presented an additional
objectionable characteristic. In the most normally utilized system, the drive
unit, such as a wobble box is situated at the front of the header in line with
the sickle bar. This positioning of the drive system establishes a dead area,
i.e., a length of the front of the header is not capable of cutting a swath of
the standing crop which results in a narrow swath, and/or crop being
damaged so as to reduce total yield.
In an attempt to reduce the problems of sickle bar failure which have
worsened with the use of longer sickle bar systems and higher reciprocating
speeds, the cross sectional size of the sickle bar has been increased. This
solution in turn has been, however, self-defeating to some extent, in that
the increased weight is not only undesirable at the front most portion of
the header and requires higher power input which also adds to the weight
of the header. Moreover, the increased weight increases the inertial forces
developed in the reciprocation of the sickle bar, which are a factor in the
sickle bar vibration and failure.
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Summary Of The Invention
It is an object of the present invention to provide a reciprocating
sickle system capable of operating an elongated sickle bar with reduced
sickle bar failure.
It is another object of the present invention to provide a relatively
simple high speed sickle reciprocating system which generates reduced
vibrations.
It is yet a further object to provide a sickle system wherein the sickle
bar is effective driven from a rearwardly positioned drive unit.
According to the present invention, there is provided a sickle bar
apparatus for use in harvesting equipment or the like, for cutting
vegetation and the like, wherein the apparatus includes an elongated sickle
bar means extending between opposite outer end portions thereof for
presiding along a forward cutting edge of the harvesting equipment, and an
equalizing means having opposite outer end portions and being disposed
behind and in substantially parallel relationship to the sickle bar member.
There is further provided a pair of connecting means one each being joined
between corresponding end portions of the sickle bar and the equalizing
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means to thereby form therewith a closed loop wherein the reciprocating
motions of the sickle bar and the equalizing means are 180 out of phase.
A tensioning means is associated with the means forming the closed loop to
maintain an elongated stretching force on the sickle and equalizing means
sufficient to maintain the sickle bar in a tensioned condition through all
reciprocating motion thereof.
In a preferred embodiment of the invention the equalizing means is
formed by a member of a weight selected to at least partially cancel
momentum effects of the sickle bar means so as to thereby reduce
1o vibration causing forces of reciprocation of the sickle bar means.
In one preferred embodiment of the present invention, an input
drive unit is mounted on the frame structure of the harvesting equipment
rearwardly of the equalizing means, and there is provided a driven output
reciprocating means extending forward therefrom and being connected to
one of the means forming the closed loop for imparting said reciprocating
motion to said sickle bar means and said equalizing means in said closed
loop.
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Brief Description Of The Drawings
In the accompanying drawings, which show various embodiments of
the invention as examples;
Figure 1 is a partial top perspective view of the reciprocating sickle
system of one embodiment of the present invention shown in isolation
from the combine header or other types of mowing equipment in which it
may be utilized;
Figure 2 is a view similar to Figure 1, again shown in isolation, except
for additional detail of one form of an adjustment mechanism which
1o attaches to an outer end of the system to the frame of such equipment for
adjusting the tension applied to the bar;
Figure 3 is an enlarged side view of the tension adjustment
mechanism of Figure 2;
Figure 4 is a view similar to Figure 2, but illustrates another
embodiment of the invention;
Figure 5 is a view also similar to Figure 2, but showing yet another
embodiment of the present invention;
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Figure 6 is a further view of the embodiment of Figure 5, but
enlarged and with parts removed to better reveal a sickle bar drive system
different than those revealed in Figures 1 to 4;
Figure 7 is a perspective view of a portion of the framework of a
header incorporating the present member and wherein the sickle bar drive
unit is located at the very rear of the header framework;
Figure 8 is a perspective view similar to Figure 7 but of another
embodiment of the invention;
Figure 9 is also a perspective view of yet another form of the present
1o invention;
Figure 10 is a perspective view of the right hand end portion of the
embodiment of the invention of Figure 9 shown on an enlarge scale for the
sake of clarity;
Figure 11 is a view similar to Figure 9, yet showing an embodiment of
a further modification of the present invention; and
Figure 12 is a view similar in nature to Figures 9 and 11, and showing
yet a further embodiment of the present invention.
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Detailed Description Of The Invention
Referring first to the embodiment of the sickle bar system of Figures
1 to 3, which embodiment is generally denoted by the reference number
20, it can be seen to include a sickle bar assembly per se designated at 21.
In the usual manner, a sickle bar 28 per se of the sickle bar assembly 21 has
affixed thereto a plurality of juxtaposed knives 22, which knives 22 are
connected to the sickle bar 28 and reciprocate transversely relative to the
header within a plurality of juxtaposed guards 23 which are bolted to a bar.
The bar is bolted to the frame of the header, a short portion of such bar
1o being shown at 24 on Figure 1. The interaction of the reciprocating knives
22 within the guards 23 shear standing plants as the harvesting equipment
or the like moves through the crop. In the situation where the sickle bar
assembly 21 is constructed in a header for a combine unit, cut crop then
falls rearwardly relative to the sickle bar system 20 onto a conveyor
arrangement (not shown) carried within the framework of the header
whereby the conveyor then moves the cut crop to a feeder system (not
shown) provided for rearwardly transferring the cut crop into an intake of
the combine.
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The sickle bar 28 is shown as an elongated unitary bar, which would,
in the most commonly used types of headers, extend across a major
portion of the front of the header. Located at opposite ends of the header,
which form short non-cutting outside or dead portion of the front edge in
the embodiment now being described, are located a sickle bar drive unit
25 at a drive end of the sickle bar and a non-drive or idler end structure 26,
partially shown in Figure 1, at the opposite end. In the illustrated
embodiment, a wobble box 27 is utilized at the drive end, the power input
to the wobble box 27 being provided by a drive belt or like, not shown,
1o through a pulley 30 to an input shaft of the wobble box. A base member of
the wobble box is affixed to a frame section 44a of the header (Figure 2).
The above mentioned drive belt is driven from a power take-off system (not
shown) of the combine. As indicated by the double-headed arrow 31a,
the output drive of the wobble box is in the form of a reciprocal oscillation
about the vertical axis of a shaft (not shown). The output shaft is attached
to a substantially horizontally disposed drive member 32 affixed to the
shaft of the wobble box so as to transfer thereto the reciprocal oscillating
drive motion. The drive member 32 in the illustrated embodiment is much
in the form of a partial sprocket providing axially oppositely disposed,
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arcuate shaped toothed sections forming drive throws 34 and 35, throw 34
being drivingly attached at the front to an end of the sickle bar, and throw
35 at the rear being drivingly attached to an equalizing member 33 which is
located behind and parallel to the sickle bar. In the present embodiment
the member 33 is shown as being a rigid, metal bar effectively parallel to
and extending substantially the length of the sickle bar. The sprocket-like
toothed front drive throw 34 and the similar toothed rear throw 35 in the
shown embodiment provide pulling drive forces at the same radial distance
from the centre of the axis of the output shaft of the wobble box. A first
1o short chain section 36 is attached at one free end 37 thereof to the front
throw 34 and meshes with this associated toothed throw. That short chain
section is attached at its opposite free end to one end of the sickle bar
assembly 21 as shown at 37. A similar short chain section 38 is similarly
attached between the rear throw 35 and a free end (not shown) of the
equalizing member 33.
The idler end 26 is provided by idler throw member 40 of a form
similar to that of drive member 32 in that it includes sprocket-like idler
member 40 providing throws attached to the outer ends of the sickle bar
28 and the equalizing member 33, again by short chain sections 39,39. The
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member 40 is mounted for free reciprocal oscillating by way of a vertical
shaft (not shown in Figure 1) carried in a hub or bearing section 42 (Figure
3) of an adjustable tensioning assembly indicated generally by 43 in Figure
3; and this assembly 43, shown in more detail in Figure 3, connects the
outer end of the sickle bar assembly 21 to a stationary frame section 44b of
header.
It can be seen therefore that sickle bar assembly 21, equalizing
member 33 in conjunction with drive member 32 at one end and the idler
end structure 26 at the other end effectively form a closed loop. The
1o reciprocal oscillating imposed by the drive member 32 causes the sickle bar
assembly 21 to reciprocate within the guards 23, and in view of the nature
of the drive member 32 idler end 26, this motion is in a straight line as is
the reciprocating motion imposed on the equalizing member 33. At any
instant the speed and the state of acceleration or deceleration in the sickle
bar and equalizing members are identical in the opposite direction. In the
case shown, where the effective throws formed by the drive member 32
and the idler end 26 are equal, the speed and the state of acceleration or
deceleration at any moment are equal but in opposite directions. In the
case where the weight of the equalizing member 33 is also selected to be
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the same as that of the sickle bar assembly, the momentum of the two at
any instant are the same but in opposite directions, effectively providing a
cancellation of these linear vibrational forces. It is apparent that by
varying the effective lengths of the throws provided for the sickle side of
the drive 32 and the idler member 40 in relation to those on the side of the
equalizing member 38, the same balancing can be achieved by increasingly
changing the relative weights of the sickle bar and equalizing member.
Referring now to Figures 2 and 3, there is provided a system
tensioning mechanism 49 for establishing and maintaining a minimum
1o tension in the sickle bar. It is to be noted that the bearing section 42
(Figure 3) is formed at its upper end integrally with a plate member 45
providing a flat upper surface 48 for engagement with a flat under surface
of frame member 44b. The plate 45 is provided with a number of slotted
openings 46 which are positioned to align with openings 47 in the frame
section 44 of the header. The openings 46 are elongated in a direction
aligned relative to the header and the direction of the elongated sickle bar
assembly 21. Bolts 50 which pass through openings 46 and 47 are provided
for holding the upper surface of plate member 45 in tight engagement with
an under surface of frame section 44 to thereby prevent relative movement
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between the plate member and the frame section when the bolts are
tightened.
An anchor member 52 is secured to the upper surface of the frame
section 44b by way of the two outermost pair of bolts 50,50 and provides
an upstanding flange 53 having an opening for receiving a horizontal
tensioning bolt 54. The bolt 54 projects over an opening 55 (Figure 2) in
the frame section 44b, thus exposing a portion of the upper surface of the
plate 45. Affixed to an upper surface of the plate member 45 is an
upwardly projecting brace member 56 which extends upwardly through an
1o opening 55 of frame member 44b. The brace member 56 is provided with
an opening in alignment with the opening in the upstanding flange 53. The
free end of the bolt 54 receives a plurality of disc springs 58, between a nut
57 and the brace member 56 whereby on tightening of the nut, a graduated
force is provided to the brace member 56, thereby forcing the other idler
40 away from the drive unit 25, which is affixed in position relative to the
frame of the header, and thereby increasing equally the tensional forces
applied to the sickle bar assembly and equalizing member 33. As
previously indicated herein, serious problems have developed in the most
commonly used drive systems of the sickle bar as attempts have been
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made to increase the sickle bar length and/or the rate of reciprocation of
the sickle bar so as to improve the speed of harvesting. The end result of
such problems is unacceptable vibration and/or frequency of breakage of
the sickle bar. Better designed wobble boxes have provided an improved
input in relation to the rate of acceleration and deceleration of the blade,
but testing has revealed that a significant factor in the case of failure
resides in the repeated alternating compression and tension experienced
by the bar which is commonly driven from one end. As can be appreciated
in considering the present invention, as illustrated in Figures 1 to 3 and
1o described to this point, the sickle bar and its attached knives and the
equalizing member 33, together with the drive member 32 and idler end 40
which connect these parts, effectively provide a closed loop. Because the
non-drive or idler end 40 of the present invention includes the tensioning
system 49, adjustment can be made as to the position of the plate member
45, and thus the distance of the non-drive or idler end 26 away from the
drive end 25 so as to thereby place the closed loop containing the sickle bar
and equalizing member 33 in tension permanently. In the embodiment of
the invention described to this point, the final amount of tension can be
established by the selection of the appropriate number and character of
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the disc springs 58. Of course, the determination of the amount of tension
being applied to the system can be done by other means, but it is
important that the amount of tension in the length of the sickle bar 28 and
equalizing member 33 of the closed loop be relatively accurately
determined for reasons further indicated below. Once the tension has
been applied, the bolts 50 are tightened so as to prevent movement of the
idler end 26 relative to the frame. Thus, in the reciprocation of the sickle
bar assembly 21, during the outward stroke, it is pulled by the wobble box
25, through equalizing member 33 and idler end 26, and it is pulled through
1o its inward movement during the return stroke directly from the drive
member 32. Thus, as the forces applied for movement of the bar in both
directions are through the pulling forces from opposite ends, and the initial
presetting of the bar is set in tension by the position of the idler end 40,
the
bar does not at any time experience compression forces. This situation
avoids any buckling effect in the bar as well as repetitious exposure at the
bar to rapid cycling tension/compression conditions, which are known to
result in work fatigue of the steel, and thus failure of sickle bars.
Turning now to Figure 4, which shows an embodiment of the
invention similar to that shown in Figures 1 to 3, like reference characters
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designate like parts. However, in this embodiment a different form of the
equalizing member 33, shown in this figure as a member 60, is spaced
rearwardly of the sickle bar assembly 21, is utilized. The equalizing
member or element 60, in this second embodiment consists of a number
of parts different than those of the earlier embodiment, including a main
portion consisting of a section of flexible cable shown here as a wire rope
61, which extends parallel to and is of substantially the same length as the
sickle bar assembly 21. Secured to opposite ends of the length of wire
rope 61 are end connectors 62 and 63, respectively. Inner wire rope
1o connector 62 has integrally formed therewith a rod section 64 which may
be connected to a free end of chain section 38, which in turn is connected
at its opposite end to the rear throw of the drive member 32. The outer
wire rope connector 63 has a rod section 65 provided with a threaded out
end 66 for co-operation with a cable tension adjusting assembly 69. The
tension adjusting assembly 69 includes a body having an outer end member
67 which is fastened to the free end of the rear chain section 39 at the idler
end 26, the outer end member 67 of the tension adjusting assembly being
rigidly connected to an inner end member 68 by way of a pair of spaced
side members 70,70. The inner end member 68 is provided with an
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aperture through which passes the threaded outer end 66 of the outer rope
connector 63. A pair of nuts 71,71 are threaded onto outer end 66 of the
rod 65, one each on opposite sides of the end member 68 of tension
adjusting assembly 69. Thus, during the setting of the tension in the closed
loop including the parallel extending sickle bar assembly 21 and equalizer
member or element 60 in the embodiment of Figure 4, the nut 71 which is
outside of the assembly 69 is loosened and the nut 71 on the inside is
tightened to pull the outer threaded rod 66 through the inner end part 68,
until the proper equal tension is obtained in the sickle bar and wire rope
61. The outer nut 71 is then tightened to maintain and lock the set tension.
It may be noted that plate 45b corresponds in part to plate 45 shown
in Figures 2 and 3, except that it is affixed to a frame member (not shown)
of the header by bolts passing through openings 46b, 46b, which are not
slotted as shown in the previous embodiment. The earlier described
tensioning system 49 of Figures 2 and 3 is unnecessary in the embodiment
of Figure 4, as the cable tensioning, and indeed, the overall tension applied
in the equalizing member 60 in the form of the cable assembly and in the
sickle bar 28 as well are achieved by way of cable tensioning assembly 69.
Again, in assembling the components of the equalizing member 60,
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the weight of components may be designed to be in total substantially the
same as that as sickle bar assembly 21 in order to achieve the balanced
condition which brings about the cancellation of the reciprocating
momentum of the sickle bar assembly.
The use of the wire rope in place of a rigid metal bar forming an
equalizing member or element 60 as illustrated in the previous
embodiment has a number of advantages, particularly in view of the
considerable distance spanned by this member. The handling, shipping and
storage of the long rigid bar, as a separate part can be cumbersome,
1o whereas the wire rope can be handled and store in a rolled up form. While,
the wire rope may experience some permanent stretching in use due to the
fact it is in a continually tensioned condition and subjected to significant
forces which occur during its rapid reciprocating operating conditions, such
permanent elongation can rather quickly be compensated for by occasional
testing and manual resetting through the cable tensioning assembly 69.
Yet a further embodiment of the invention, not illustrated in the
drawings, may involve the forming of the equalizing member by way of a
number of separate rigid rod sections, formed of steel or the like, arranged
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end-to-end to provide a continuous member of the length of the previously
described rope member. Such rods may be formed so as to have mating
internal/external threaded ends which can be readily turned together to
form the continuous full length of the equalizing member. The use of short
lengths of individual rods does have the advantage of facilitating handling,
shipping and storage, and because the single member formed thereby is
continuously subjected to only varying amounts of tension, it does not
encounter problems which could result if it continually experienced rapid
alternating tension and compression conditions.
Referring now to the embodiment of Figures 5 and 6, the overall
sickle bar system is denoted 20c, and includes the drive unit 25 mounted at
one end of the system on a frame member 44a of a combine header. The
sickle bar system is mounted at the opposite or idler end 75 on a frame
member 44b of the head. The equalizing member 60, as well as the cable
tensioning assembly 69, are the same as like elements shown in Figure 4.
The sickle bar assembly 21c is in the main the same as those of the
previously described embodiment, but includes a different type of drive
connections 76a,76b, adjacent opposite ends thereof.
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The vertical output shaft (not shown) of the drive unit 25 projects
through the base of the unit and the header frame member 44a (Figure 5),
and it has connected thereto a drive member 77 providing a pair of
diametrically opposed drive arms 78a, 78b whereby such drive arms are
provided with an arcuate oscillating motion by the drive unit 25 as
indicated by arrow 91 (Figure 6). In the present embodiment, the arms 78a
and 78b are of equal length and provide at approximate equal distance
from the centre of the drive shaft of drive unit 25 a pair of pivot bolts 79,
one of which is shown for the connection to an inner end of the bar 28 of
1o the sickle bar assembly by a rigid drive connector link 82 of the drive
connection 78a and the second of which (not shown) pivotally connects the
rear drive arm 78b to one end of the equalizing member 60.
At the outer or idler end 75, an idler connecting member 86 having
arms 88a, 88b is mounted for free pivoting on a shaft 81, which is affixed
relative to a frame member of the header. The arm 88a is pivotally
connected by a bolt connection 89 to the outer end of a link 82 of an
outer connector assembly 76b. The inner end of link 82 of the connector
assembly 76b is connected by a bolt connection 87 to a rigid connection
member 92 which is affixed to the sickle bar assembly 21c. The inner
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connector assembly 76a at the drive end and the outer connector assembly
76b at the idler end of the sickle bar assembly 21 may be of like assembly.
The only difference in the parts at the drive end and idler end is that the
member forming the drive member 77 at the inner end is affixed to the
output shaft of the drive unit 25 for oscillation therewith while at the outer
end the oscillating member is mounted for free arcuate oscillation
movement as indicated by the arrow 91.
With respect to the equalizing member 60, it is to be noted that
there is provided at its outer end in the connection to the arm 88b by way
1o of a cable tensioning adjustment assembly 69 as in the previously described
embodiment of Figure 4.
The sickle bar connector assemblies 76a, 76b at opposite ends of the
sickle bar 28 may be of identical structure. The assemblies 76a, 76b each
include the elongated bar-like link 82 which in the case of connection 76a is
pivotally connected at one end to the front arm 78a of the pivoting drive
connector member 77 and at its outer end or free end it is pivotally
connected at 87 to a rigid connector member 92 having a length thereof
affixed to the sickle bar assembly 21. It is to be noted that the connector
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member 92, as affixed to the sickle bar assembly 21 at each end of the
sickle bar assembly, is spaced from the actual end of such assembly. Thus,
due to the extended length of the connector link 82 little side-ways force is
applied to the edge of the bar 28 in its engagement of its side with the
stationary components of the assembly even though the tensional forces as
applied to the bar have a slight side-ways component.
As in the embodiment described in relation to the embodiment of
Figure 4, there is no need for providing adjustment of the mounting of the
idler end component 75 in the currently discussed embodiment in that the
1o amount of tension with the sickle bar 28 and the equalizing member 60 is
set and maintained at a pre-tensioned condition by the tensioning adjusting
assembly 69. Accordingly, the tension experienced for substantially the
entire length of the bar 28 which is located between the connector
members 92,92 during the complete cycle of reciprocating does not
approach a compression condition at any time.
As previously indicated, with the continued increase in the width of
the header, and thus longer sickle bars, it has been necessary to increase
the size of the drive unit. This increased size has resulted in an increased
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cutting dead area at the front of the header, and its increased weight at a
front corner of the header has also had a detrimental effect on the
requirements of the frame of the header with respect to frame strength
and maneuverability. Moreover the frontal positioning of the heavy drive
unit is a factor in the required power input for raising and lowering of the
extra weight at the front of the header.
Figure 7 illustrates an embodiment of the invention wherein the
drive unit 25, which is in the form of a wobble box, is located at the rear of
the framework of the header. In this Figure, there is a main frame member
100 of a header, this member which is one of a number of several members
spaced along the transverse width of the header has an upright portion 101
and a slightly downward and forwardly projected portion 102 formed
integrally therewith. The overall sickle bar assembly 21c of the present
invention is carried by frame members (not shown) forwardly of the front
end of the forwardly projecting portion 102 of the framework, a conveyor
structure (not shown) being provided above a series of such frame portions
102 for directing the cut crop away from behind the sickle bar assembly
towards a rearwardly transfer conveyor (not shown). The attachment of
the overall header to the combine unit is achieved by a central attaching
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arrangement (not shown) associated with centrally disposed upright
portions 101 of the overall framework. The input power for operating the
necessary operating parts of the header, such as the transfer conveyors, is
provided from the combine unit through a central attaching arrangement.
Likewise the power input from the combine unit is supplied to the power
unit 25 of the sickle bar assembly 21c.
In the example shown in Figure 7, power is provided to the drive unit
25 which is in the form of a wobble box mounted on a transverse rear
member 104 of the header framework, from a PTO shaft (not shown)
1o connected to an input shaft 103 of the drive unit 25. A second transverse
supporting frame member 105 is located a distance forward of the
rearward mounted transverse frame member 104.
The sickle bar assembly 21c is shown as an arrangement substantially
the same as that of Figures 5 and 6. However, it is important to note that
because the embodiment of Figure 7 is not driven from an end mounted
drive unit similar to that shown in the previous embodiments, the sickle bar
assembly can extend substantially the full width of the header, thus
avoiding an extended dead area at the front of the header. Further
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CA 02690386 2010-01-20
description of the sickle bar assembly 21c as a whole is thus believed
unnecessary except to emphasize that it does not include a drive input
mechanism such as that shown, for example, at 77 in Figure 6. There is
shown in its place what has been termed herein as an idler end 86' of the
same construction as that used at its opposite end shown in Figure 7 at 86.
There is no power input to the sickle bar assembly at either end, but by a
power input system 106 disposed behind the sickle bar assembly and
driven by the wobble box 25. As previously shown the drive unit 25, such
as a wobble box has an output shaft providing an arcuate oscillation as
1o indicated by arrow 107. Attached to this vertical output shaft of the drive
unit 25 is a drive unit 77' providing a pair of diametrically opposed rigid
drive arms 78' and 78' to which are pivotally connected a pair of forwardly
extended elongated rigid drive links 108,108 which are thereby driven in
substantially longitudinal lengthwise reciprocation as indicated by arrows
110,110. The forward end of the links 108,108 are pivotally connected at
109,109 to opposite ends of rigid pivoting cross bar assembly 111. The
cross bar assembly 111 is mounted on the header frame by a central shaft
112 so as to be free for arcuate oscillation as shown by the arrow 113.
Rigidly affixed to the cross bar assembly is a forwardly projected tongue
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portion 114 having at its outer end a clamp mechanism 115 disposed in line
with the longitudinal axis of the wire rope 61 which forms the equalizing
member 60 of the sickle bar system, the oscillating motion of the tongue
being indicated by the arrow 116. The drive input to the sickle bar
assembly is thus achieved from behind the sickle bar assembly by injecting
the reciprocating power through the equalizing member 60. As before, the
closed loop in this embodiment consists of the sickle bar and the equalizing
member, joined through means including a pair of idler connecting
members 86,86'. Also as before this closed loop is maintained tensioned so
1o that the sickle bar and equalizer member are maintained in a preset
tensioned condition whereby the sickle bar never enters a lengthwise
compressed state.
In Figure 8, another embodiment of a drive unit of the invention is
shown mounted on a header frame member behind the sickle bar assembly
21c, in a manner similar to that in Figure 7. As shown in Figure 8, this
embodiment provides a sickle bar system 21c mounted on a header
framework as illustrated for the previously described embodiment of the
present invention. The embodiment of Figure 8 utilizes a different drive
arrangement for the sickle bar system in place of a wobble box previously
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described. Instead of the input drive 105 being connected to a wobble box,
it directly drives a pulley 120 carried on a mounting structure 121 affixed to
the rear frame member 104. A belt drive 122 drives a second pulley system
123 which has connected thereto a horizontal projected eccentric shaft
124. A reciprocating drive shaft 125 has one end connected through a
universal connection 126 to the eccentric shaft 124, and at its other end
through a universal connection 127 to an arm 128. Arm 128 is integrally
formed with a forwardly projecting tongue portion 114a of a structure
corresponding to the rigid tongue member 114 of the previous
1o embodiment. The unit forming the arm 128 and tongue member 114 are
mounted for allowing a pivot motion 129 by a pin 130 forming a pivot axis.
Thus, the reciprocation as indicated by arrow 131 provided in the drive
shaft 125 by its connection to the eccentric shaft 124 results in the
oscillation pivoting 132 in the connecting arm 128 and tongue member
114a, and this in turn drives the rope 61 in reciprocating fashion as
indicated by arrow 131. The input of the reciprocation motion of 133 of
equalizing member 60, or wire rope 61, which is in the closed loop which
includes this member (61) and the sickle bar 20, thus provides power input
for the reciprocation cutting motion to the sickle bar 28, while, as before
CA 02690386 2010-01-20
indicated, the loop has been set in a tensioned manner to the extent the
cycle bar remains at all times under longitudinal tension.
In Figures 9 and 10, there is shown another embodiment of the
invention wherein the drive unit 25, again in the form of a wobble box 27, is
mounted on a rear frame member (not shown) of the header, and receives
drive power through a PTO shaft 103 (Figure 9). As shown in these Figures
the overall sickle bar assembly 21d, including the manner in which it is
mounted between idler end connectors 86, 86', is shown to be of the same
structure as that of Figures 7 and 8, as is the equalizing member 60 which
1o is in the form of a steel wire rope 61. As shown in Figure 9, there are
provided a pair of cable tensioning member 69, 69 one each at either end
of rope 61. Also as previously described, the closed loop formed by the
sickle bar per se 28, the equalizing member 61, and the idler connections
86 and 86' form a closed loop which are preset to a stretched condition so
as to maintain the sickle bar under positive tension at all stages of the
reciprocation of the sickle bar 28.
The manner in which the reciprocating drive for the sickle bar 28 is
transferred to the closed loop and thus then to the sickle bar from the drive
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unit 25, which is mounted at the back of the header, is different than that
of what is shown in previous Figures. Mounted forward of the drive unit 25
on a header frame member 140 is power transfer unit 141, including a pair
of pivotal members 142,142 providing curved outer guide surfaces
143,143. The pivotal members 142,142 are mounted for free swinging
movement on pivots 144,144 affixed to a stationary base plate 145 which is
affixed to frame member 140. The radius of the guide surfaces, i.e., the
distance from the centre of axis of the respective pivots 144 is such that
guide surface is immediately below the wire rope 61. A pair of drive
transmitting members 146,146, which may be formed of a fiber rope are
pivotally connected at one end to opposite output arms 150,150 of a
reciprocating input member 147 of the wobble box 27. The ropes 146,146
pass around the outer curved surfaces 143,143 of their respective pivot
members 142,142 and are clamped to a mid section of the respective
surfaces of the pivot member so as to be held tightly thereagainst by
clamps 148,148 (Figure 10).
Accordingly, ropes 146,146, which are installed under tension and
are reciprocated by the output drive unit 25, as indicated by double headed
arrows 151,151 (Figure 9) pass around through 90 degrees on the pair of
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curved surfaces 143,143 of pivot members 142, 142, and extend laterally
outward immediately under the wire rope 61, in opposite directions to
clamps 154,154 at opposite ends of wire rope 61. Each of the clamps 154,
154 has affixed thereto an extended threaded rod 157 which form part of
the tension clamp 69. Each clamp 154 is in the form of a dual clamp so as
to receive the one end of wire rope 61 of the equalizing member 60 in an
upper portion 156 of the clamp and at the same time clamp in a lower
portion 157 of the clamp under the end of the wire rope, the outer end of
one of the drive transmitting fiber ropes 146. As previously described, the
1o clamps at the outer ends of the equalizing member, in this case clamps 154,
154 are provided with threaded rod sections 65 which provide for
tensioning of the wire rope in its manner of connection in the cable
tensioning assembly 69,69. The clamps 154, 154, on tightening of the turn-
buckle like tensioning clamps thus jointly set the tension in the closed loop
containing the sickle bar 28 and equalizing member 60, as well as tension in
the pair of fiber drive ropes 146,146. The attaching of the ropes 146,146 to
the loop containing the sickle bar 28 and equalizing member 60 thus
transfers the reciprocating power introduced by the drive power from unit
into the closed loop containing the equalizing member 60 and the sickle
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bar 28, the reciprocating power thus effectively being alternately
introduced in an inward pull exerted through the clamps 154.
Looking now at Figure 11, this is to some extent a simplified form of
the invention shown in Figures 9 and 10, but is one which may be
satisfactory for use in certain types of headers or mowers. Most reference
characters previously utilized in Figures 9 and10 show common or like
components in Figure 11.
As pointed out in relation to the previous embodiments the sickle bar
and the equalizing means, the latter of which is a rigid bar member in the
1o embodiment of Figures 1 to 3 and a steel rope in the embodiments of
Figures 4 through 9, together with the idler end and the driving end, as in
the embodiment of Figures 1 to 6, or both idler ends as in Figure 6 through
8, formed a closed loop. The closed loop feature provides the important
ability of maintaining the sickle bar always in tension throughout the entire
sickle bar cycle. Moreover, because the travel of the sickle bar and the
equalizing member are always in opposite directions cancellation of
otherwise produced vibration of the reciprocating of the sickle bar is
achieved.
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In the embodiment of Figures 10, the maintenance of preset tension
in the closed loop which includes the sickle bar and the steel rope as well as
the balancing of the weights of these components travel in opposite
directions is achieved by the presence of the equalizing means in the form
of the steel rope. The existence of two fiber ropes are effectively outside of
this loop, but are likewise maintained in tension by the same cable
tensioning assembly 69,69. Thus, the weight of the two separate lengths of
the ropes 146,146 together with the steel rope 61 contribute to the
balancing effect in relation to the opposite movement of the sickle bar
1o assembly.
Referring to the embodiment of Figure 10, it can be seen that in view
of the absence of an element corresponding to the rigid bar or steel rope of
the earlier embodiments, there still exists a closed loop which includes not
only the sickle bar and the two sections of the ropes 146a, 146a which are
parallel to the sickle bar but as well as the two sections 146b and 146b
which extend rearwardly to the drive input member 147 of the drive unit
25. While in the case of this simpler drive system, it is apparent that the
extended closed loop provides an equalizing means in the form of two
sections 146a, 146a which are travelling in opposite directions to the sickle
CA 02690386 2010-01-20
bar. Where these sections are formed of fiber rope, the cancellation of the
vibration feature caused by the sickle bar may not be as effective due to
the differences in weight. However, even in this simplified design, it is
possible to maintain at least the major portion of the sickle bar between
s the end connections 92,92 in sufficient tension through each reciprocation
of the sickle bar so as to avoid stressing of the sickle bar due to the
constant subjecting the bar to repetitive reversing of tension and
compression stressing. This alone permits the possibility of utilizing a
sickle
bar of decreased cross section.
io Figure 12 is an embodiment similar in certain aspects to that of
Figure 11 in that while the side bar and equalizing means are in closed loop,
additional elements are in the closed loop as well. Again this embodiment
provides for the location of drive unit 25, which is again shown in the form
of a wobble box 27 having an output 147. As before described the wobble
15 box provides an arcuate oscillation input as indicated by the arrow 107
into
the closed loop forming the eventual drive of the sickle bar 28. As
described before the output 147 includes a pair of diametrically opposed
arms, one of which is shown at 150.
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In this embodiment there is again provided a base plate 145 at a
location which might be termed a power transfer area carried by a header
frame member 140 forward of the drive unit 25. On opposite sides of the
frame member there are mounted by way of pivot means 144,144 Bell
crank units 160,160. The Bell crank unit has a pair of arms 161,161
projecting in a transverse direction and a pair of arms 162,162 projecting in
the longitudinal direction. A pair of steel rods 163,163 are connected one
each at a rear end to the pair of arms 150,150 of the output arms of the
output 147 of the drive unit 25, and at the forward end to the arms 161 of
1o the bell cranks 160,160. A pair of transversely disposed steel ropes
164,164
are connected at inner ends to the arms 162,162 of the Bell Crank units and
at their outer ends to the rods 65 of the rope tensioning means 69, and
thus effectively to the rearward arm of the idler connection member86,86.
In the embodiment of Figure 12 it can be seen that the closed loop
1s containing the sickle bar 28 is in effect also extended as compared to the
embodiments of Figures 1 to 10, in that the closed loop effectively includes
in combination with the two lengths of steel ropes 164,164 basically
forming the equalization means, the arms 161,161 and 162,162 of the Bell
crank units 160 and the longitudinal extending steel rods 163,163 leading to
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the output member 167 of the drive unit. Unlike the construction of the
previous embodiment of Figure 11, the lengths of the steel ropes 164,164,
which are reciprocating in a direction exactly opposite to the sickle blade
are more effective in cancellation of the vibration affect of the sickle
blade.
While a number of examples of the features forming the present
inventions have been shown and described, other variations within the
scope of the invention as defined in the appending claims will be obvious to
those skilled in the art.
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