Chopping mechanism with remote shearbar adjuster

The shearbar of a forage chopper, positioned in such a way that direct access thereto for adjustment purposes is obstructed by other adjacent structures and mechanisms, is provided with an adjuster which may be manipulated at a point remote from the shearbar itself under conditions providing free, uninhibited access to the adjuster. A cam in the nature of a wedge is shifted infinitely along a path of travel that causes responsive shifting of the shearbar assembly along a path of travel extending toward and away from the chopper when a setscrew is released to permit such shifting on the part of the assembly.

TECHNICAL FIELD 
This invention relates to harvesting equipment, and more particularly, to 
unique means for adjusting the position of a shearbar with respect to its 
cooperating chopper on forage harvesting equipment. 
BACKGROUND ART 
Forage choppers typically employ chopping "cylinders" which rotate at high 
speeds and cooperate with stationary shearbars to chop incoming crop 
stalks and the like into small segments. The relationship of the shearbar 
to the knives of the cylinder is critical to achieving proper severance 
and uniform length of chopped segments. Thus, it is essential that the 
position of the shearbar be adjustable with respect to the chopper so that 
accommodations can be made as may be necessary or desirable for wear on 
the part of the knives and the shearbar tending to militate against the 
quality of chop obtained. In some situations, however, the shearbar is 
located in an area in which direct access thereto is obstructed by 
adjacent equipment and structures, making adjustment difficult and tending 
to discourage proper periodic adjustment. Furthermore, the degree of 
accuracy and precision involved in prior adjustments has not been all 
together optimum. 
SUMMARY OF THE PRESENT INVENTION 
Accordingly, one object of the present invention is to provide a shearbar 
adjusting arrangement which, by its inherent ease of use, ready 
accessibility and precision control encourages frequency of shearbar 
adjustment that is consistent with the goals of obtaining high quality 
chopping performance. 
Pursuant to the foregoing, the present invention contemplates a pair of 
adjusters at opposite ends of the shearbar assembly, each including a 
long, generally upstanding operating member having a head rising above the 
chopper box or housing on which the adjusters are mounted. A similarly 
positioned, long setscrew associated with each adjuster is likewise 
positioned with its head above the chopper box for ease of manipulation 
and accessibility, it being possible when the setscrews are loosened to 
individually rotate the adjuster members with a wrench or the like to in 
turn shift a cam of each adjuster in a direction which either draws the 
shearbar closer to the chopping cylinder or allows a spring of the 
adjuster to push the shearbar back out away from the cylinder. As a result 
of the special geometrical relationship between the setscrew of each 
adjuster, the surface which it normally engages, and the path of travel of 
such surface with the shearbar, the latter is not only clamped by the 
setscrew against accidental movement into the cylinder, but is also 
positively stopped against such movement when the setscrew is properly 
positioned.

DETAILED DESCRIPTION 
The chopping mechanism 10 includes a housing 12 provided with a pair of 
spaced apart sidewalls 14 and 16 and a topwall 18 spanning the sidewalls 
14,16. The housing 12 has an opening 20 defined between the sidewalls 
14,16 and below the topwall 18 at one end of the housing 12. The opening 
20 is adapted to permit the entry of crop material into the housing 12 for 
severance by a rotating chopping cylinder 22 in cooperation with a 
shearbar assembly 24. The chopped material leaves the housing 12 via the 
opposite end thereof through an outlet 26. 
The cylinder 22 spans the housing 12 and is suitably supported at its 
opposite ends by the sidewalls 14,16. Likewise, the shearbar assembly 24 
spans the housing 12 at a point below the axis of rotation 28 of the 
cylinder 22 and rearwardly adjacent the opening 20, effectively forming 
the lower limit of the opening 20. Thus, crop material entering the 
housing 12 passes over the shearbar assembly 24. 
The shearbar assembly 24 includes a shearbar 30 of elongated nature and 
rectangular, transverse cross-sectional configuration, the shearbar 30 
projecting for a short distance outwardly beyond respective ones of the 
sidewalls 14,16 and resting upon a heavy-duty support bar 32 likewise 
traversing the housing 12 and extending outwardly beyond the sidewalls 
14,16. The support bar 32 is fixedly attached to the housing 12 and has an 
uppermost, flat surface 34 inclined upwardly toward the cylinder 22 and 
slideably supporting the shearbar 30 for transverse movement thereof along 
a path of travel extending toward and away from the cylinder 22. Each end 
of the support bar 32 is provided with a generally U-shaped bracket 36 
welded or otherwise fixed to the corresponding sidewall 14 or 16 and 
including a lower rigid leg 38 projecting from beneath the proximal end of 
the support bar 32 generally toward the outlet 26, an upper rigid leg 40 
spaced above the shearbar 30 and extending in parallelism with the lower 
leg 38, and a rigid bight 42 interconnecting the legs 38 and 40 adjacent 
the ends thereof which are remote from the opening 20. The bight 42 
extends at right angles to the legs 38 and 40. 
In addition to shearbar 30, the assembly 24 further includes a pair of 
inverted, generally C-shaped blocks 44 and 46 at opposite ends of the 
shearbar 30 and having downwardly facing notches 48 that receive 
respective, corresponding portions of opposite ends of the shearbar 30. 
The assembly 24 further includes a shank 50 projecting rearwardly from 
each block 44 respectively and threaded into the latter against the 
proximal side of the shearbar 30 so as to effectively clamp the latter 
tightly against the opposite side of the notch 48. Thus, the shanks 50, 
the blocks 44,46, and the shearbar 30 all become rigidly attached together 
and move as a unit when the shearbar 30 is shifted toward and away from 
the cylinder 22 along a path of travel defined by the top surface 34 of 
the support bar 32. 
Each shank 50 passes freely through the bight 42 of the corresponding 
bracket 36 and terminates in an outermost head 52 spaced beyond the bight 
42. A shoulder 54 is disposed inwardly of the head 52 on the shank 50 and 
bears against a cam wedge 56 which in turn bears against the bight 42 
forming a second shoulder. Both the shoulder 54 and the cam wedge 56 are 
suitably perforated to provide passage therethrough of the shank 50, the 
perforation in the cam wedge 56 being in the nature of a slot 58 extending 
longitudinally of the cam wedge 56. 
The two cam wedges 56 on opposite sides of the housing 12, together with 
the support bar 32 and brackets 36, form part of what may be referred to 
as adjusters for the shearbar assembly 24 for controlling and effecting 
shifting of the latter along the top surface 34 of the support bar 32. 
Each cam wedge 56 has one face 60 which is parallel to the corresponding 
bight 42 and slidingly bears against the latter during shifting of the cam 
wedge 56 along a path of travel transverse to the path of travel of the 
shearbar assembly 24. An opposite face 62 of each cam wedge 56 is inclined 
with respect to the face 60 thereof and converges toward the latter as the 
normally lower end of the cam wedge 56 is approached, the slanted face 62 
bearing against a similarly inclined surface of the corresponding shoulder 
54. A compression spring 64 encircles each shank 50 and is located between 
the bight 42 on the one hand and an abutment 66 on the shank 50 on the 
other hand. Consequently, the springs 64 on the two opposite sides of the 
housing 12 yieldably bias the shearbar assembly 24 in a direction away 
from the cylinder 22. 
Each cam wedge 56 has a normally upper end 68 threadably receiving the 
lower threaded end of an elongated operating member 70 which extends 
upwardly for a substantial distance above and beyond the topwall 18 of 
housing 12. Each operating member 70 is rotatably attached to the 
corresponding sidewall 14 or 16 via a lug 72 which, in cooperation with 
structure broadly denoted by the numeral 74 and located on opposite upper 
and lower sides of the lug 72, prevents axial shifting of the member 70 
during rotation thereof about its longitudinal axis or otherwise. A head 
76 at the uppermost end of the member 70 is adapted to receive rotative 
force thereto applied via a wrench or the like. 
Each side of the housing 12 is also provided with a long, upstanding 
setscrew 78 having a head 80 at its uppermost end spaced above the topwall 
18 of the housing 12 for accessibility and in generally close proximity to 
the head 76 of the corresponding operating member 70. Each setscrew 78 has 
a lowermost threaded end 82 passing obliquely through but in threaded 
relationship with a mating nut 84 held captive within an aperture of the 
upper leg 40 of the corresponding bracket 36. The lowermost threaded end 
82 of the setscrew 78 makes clamping engagement with the top, inclined 
surface 86 of the corresponding block 44, said surface 86 being inclined 
with respect to the shearbar 30 but in actuality being substantially 
parallel to the engaging end 82 of the setscrew 78. Thus, the setscrew 78 
approaches the shearbar assembly 24 at an acute angle to the path of 
travel of the latter as measured on the side of the setscrew 78 facing the 
cylinder 22, i.e., in the direction of shifting of the shearbar 30 toward 
the cylinder 22. This geometrical relationship effectively forms a 
positive stop against movement of the shearbar assembly 24 toward and into 
the cylinder 22 when the setscrews 78 are in engagement with their 
corresponding blocks 44. 
OPERATION 
The operation of the shearbar adjusters as hereinabove described should be 
apparent from the foregoing description. Thus, the manner of use thereof 
will only be briefly outlined as follows. 
If the quality of cut of forage materials entering the mechanism 10 becomes 
such as to require adjustment of the shearbar 30, it is first necessary to 
operate the setscrews 78 in directions which cause their lower ends 82 to 
back off the surfaces 86 of the corresponding blocks 44,46. Thereupon, by 
rotating the members 70 via their heads 76 in one direction, the cam 
wedges 56 will be threaded downwardly further between the shoulders 54 and 
the bights 42 of brackets 36. Consequently, the faces 62 of wedges 56 
change position as illustrated in FIG. 5, camming the shoulders 54 and 
hence the shanks 50 in a direction which causes the entire assembly 24 to 
move inwardly toward the cylinder 22. Thus, the shearbar 30 itself is 
brought closer to the cylinder 22 to improve the severing action taking 
place between the cylinder 22 and the shearbar 30. Tightening down of the 
setscrews 78 will firmly fix the shearbar assembly 24 in the selected 
position. 
In all likelihood, adjustments will be made to opposite ends of the 
shearbar 30 independently of one another and on a successive basis. 
Inasmuch as there are two sets of setscrews 78 and operating members 70, 
the angle at which the shearbar 30 approaches the cylinder 22 along the 
length of the latter may also be adjusted to the extent necessary. 
In the event that it is desired to back off the shearbar 30 from the 
cylinder 22, it is but necessary to rotate the operating members 70 in an 
opposite direction from that above described, thereby raising the cam 
wedges 56 to a certain extent, permitting the springs 64 to shift the 
shanks 50 away from the cylinder 22 as the shoulders 54 are maintained in 
engagement with the sloping faces 62 of the cam wedges 56. Consequently, 
the shearbar 30 becomes backed off to the extent permitted by the faces 62 
of the cam wedges 56. Thereupon, the setscrews 78 may be tightened down 
against the blocks 44. 
It is to be noted that in addition to significant ease of adjustment and 
accessibility, the present arrangement also permits fine, accurate 
adjustments. In this regard, it will be appreciated that movement of the 
cam wedges 56 linearly between the shoulders 54 and the bights 42 is 
controlled by the pitch of the threads on the members 70, it being 
possible to obtain very little movement of the wedges 56 per each 
revolution of the member 70 if desired. Likewise, the angle of slope of 
the faces 62 has a bearing on the displacement of the shearbar 30 toward 
and away from the cylinder 22 relative to the linear movement of the cam 
wedges 56. All of these factors may be carefully coordinated in such a 
manner to obtain very fine, accurate adjustment of the shearbar 30 if such 
is desired. 
Furthermore, it is to be appreciated that the present invention completely 
avoids sloppiness and loose fitting between interacting components such 
that there is no hesitation in the shearbar assembly should its direction 
of adjustment need to be reversed during movement in one direction. Hence, 
rapid, accurate and predictable adjustment is possible. 
The foregoing results in part from the fact that the springs 64 are 
constantly biasing the shearbar 30 away from the cam wedges 56, hence 
taking up any looseness which might otherwise tend to develop. 
Additionally, each of the structures 74 associated with the members 70 
preferably includes nylon friction washers which receive their respective 
members 70 with sufficient tightness as to prevent free turning thereof. 
This effectively locks the members 70 against accidental turning during 
regular operation of the chopping mechanism 10.