Abstract:
A support structure for a cutter bar for use in a forage harvester, the support structure adjustably supporting the opposite ends of the cutter bar and providing a convenient readily adjustable structure for supporting the central portion of the cutter bar to prevent movement of the central portion of the cutter bar relative to the cutting cylinder of the forage harvester and to afford adjustment of the position of the central portion of the cutter bar relative to the blades of the cutting cylinder.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to forage harvesters having rotating cutting cylinders and an elongated cutter bar supported in closely adjacent relationship to the cutting cylinder whereby crop material can be chopped between knives supported by the cutting cylinder and the cutter bar. More particularly, the invention relates to means for adjustably supporting the cutter bar along its length such that every portion of the cutter bar can be accurately positioned relative to the knives of the cutting cylinder and in such a manner that the center portion of the cutter bar is not permitted to bend or otherwise deform under the cutting force of the knives. 
     The forage harvesters which have been more recently developed have increased crop handling capacities and have included cutting cylinders of increased length. As a result of the use of longer cutting cylinders, complementary cutter bars have also become elongated to the extent that the cutter bars may tend to deflect or otherwise distort at their mid-sections due to the force on the cutter bar generated by crop material being cut between the cutting cylinder and the cutter bar. 
     Some of the prior art apparatus have sought to prevent this distortion of the cutter bar by securing the center portion of the cutter bar to the cutter bar support structure by a bolt or the like. However, it is generally necessary to regrind or sharpen the blades of the cutting cylinder thereby changing the gap between the cutting edge of the blades and the cutter bar and consequently it is necessary to adjust the relative position of the cutter bar. The prior art means for supporting the center portion of the cutter bar make such adjustment difficult because they are difficult to reach, requiring the operator to crawl under the forage harvester first to loosen the bolt and then later to secure the bolt after adjusting the position of the cutter bar. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved means for adjustably supporting the central portion of the cutter bar to prevent deformation of the cutter bar, and including means for adjusting the position of the central portion of the cutter bar to provide the proper clearance between the center portion of the cutter bar and the cutting cylinder, and the means for adjusting being operable from a position at the side of the forage harvester. 
     The cutter bar of the forage harvester is supported on the upper surface of a support channel and is slideable horizontally thereon, toward and away from the cylinder. The opposite ends of the cutter bar each include generally horizontal bores for receiving an adjustment bolt which is in turn supported by a bracket rigidly secured to a side wall of the forage harvester. A second pair of generally vertically extending bolts are also threadably supported by the bracket and can be received against the upper surface of the end of the cutter bar to hold it down against the cutter bar supporting channel. 
     The central portion of the cutter bar includes a bore in its bottom surface, the bore receiving an upwardly projecting end of a cutter bar guide pin which extends upwardly through a slot in the cutter bar support channel and which is rigidly attached to the end of a support shaft. Rotation of the support shaft results in arcuate movement of the guide pin, and thus the central portion of the cutter bar can be adjustably moved toward or away from the cutting cylinder by rotation of the shaft. The support shaft extends parallel to the cutter bar and to the longitudinal axis of the cutting cylinder and is positioned directly below the cutter bar and cutter bar support surface. The end of the support shaft, opposite that having the guide in attached thereto extends outwardly from the forage harvester side plate and is readily accessible. The support shaft can be secured against rotation about its longitudinal axis thereby preventing relative movement of the guide pin and horizontal movement of the central portion of the cutter bar. 
     Since the end of the support shaft extends laterally outwardly from the machine, its relative position and that of the central portion of the cutter bar can be easily adjusted. The operator is not required to crawl underneath the forage harvester thus eliminating adjustment time and reducing risk to the operator. 
     Further advantages of the invention will be made apparent in the following description of a preferred embodiment of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation view of a portion of a forage harvester embodying the present invention; 
     FIG. 2 is a cut-away perspective view of portions of the forage harvester shown in FIG. 1 and showing the cutter bar and cutter bar support; 
     FIG. 3 is an exploded perspective view of the cutter bar and cutter bar support structure shown in FIG. 2; 
     FIG. 4 is an enlarged side elevation view of the cutter bar and cutter support structure shown in FIG. 2; and 
     FIG. 5 is another perspective view of the cutter bar and cutter bar support structure shown in FIG. 2. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A forage harvester embodying the present invention is shown in FIG. 1 as including a main frame 1 having ground engaging wheels 2 (only one showing) at opposite sides and a crop receiving portion 3 which delivers the crop in a well known manner to pairs of opposed feed rolls 4 and 5. A rotating chopping cylinder C is journalled on a shaft 6, which extends between the vertical side wall 7 and 8 (FIG. 2) of the main frame 1 for rotation about its longitudinal axis. The cylinder C is shown as including a series of circumferentially spaced conventional knives 9 which, when the cylinder C is rotating, define an imaginary cylindrical surface 10. A blower B including a rotateable multi-paddle fan 12 is located at the rear of the forage harvester and acts to receive cut crop material CM which is cut by the cylinder C and thrown rearwardly into the blower. The paddles of the multi-paddle fan 12, are caused to rotate by a pulley 14 which is driven by an endless belt 15 from a power source (not shown) in a conventional manner. 
     A cutter bar or shear bar S is positioned immediately forward of the chopping cylinder C in closely adjacent relationship thereto, whereby the knives 9 may function in combination with the cutter bar S to cut crop material fed to the cylinder by the feed rolls 4 and 5. The cutter bar S extends laterally between the side walls 7 and 8 parallel to the longitudinal axis of the cylinder C and, as shown in FIG. 2, includes ends 18 and 20 which project outwardly from the side walls 7 and 8, respectively. The cutter bar S is supported by an upper flange 21 of a laterally extending cutter bar support channel 22 the support channel being rigidly supported at its opposite ends by the vertical side walls 7 and 8 within contour slots 24 and 26 respectively and is positioned such that the opposite ends 22a and 22b of the support channel 22 extend outwardly beyond the side walls 7 and 8 respectively. 
     The upper flange 21 of the cutter bar support channel 22 includes a flat upper generally horizontal cutter bar support surface 30 defining a plane which generally includes the longitudinal axis of the cylinder C. The support surface 30 of the upper flange 21 is intended to provide slideable support for the cutter bar S such that the cutter bar S is moveable in a generally horizontal plane toward and away from the cylinder C, whereby the gap formed between the knives 9 and the center bar S can be adjusted to compensate for wear of the knives and to facilitate accurate alignment of the cutter bar S. 
     In order to facilitate such adjustments or alignments of the cutter bar S, each of the opposite ends 18 and 20 are releasably secured by a set screw 32 and by a threaded cutter bar adjustment stud 34. A generally vertical plate 36 is welded or otherwise rigidly secured to each of the side walls 7 and 8 to project perpendicularly outwardly therefrom and to provide a cutter bar stud support. A generally horizontal angular bracket 38 is also rigidly secured to each of the side walls 7 and 8 adjacent the upper end of the vertical plate 36 and projects perpendicularly out from the side wall. The set screw 32 is received through a threaded bore 40 in the horizontal angular plate 38 whereby the lower end of the set screw can be received against the upper surface of the respective projecting end of the cutter bar S. The set screw 32 thus provides a means for securing the cutter bar S firmly against the cutter bar support surface 30. 
     In order to facilitate generally horizontal adjustment of the cutter bar S, i.e., movement of the cutter bar S toward or away from the knives 9, a threaded cutter bar adjustment stud 34 is received through a generally horizontal bore 44 in the vertical plate 36 and lock nuts 46 are received on opposite sides of the vertical plate 36. The adjustment stud 34 includes a portion of reduced diameter 35 receivable in a generally horizontal bore 33 in the end of the cutter bar S and a shoulder 48 to be received against the cutter bar S and a restraining nut 50 is threadably received on the end of the adjustment stud 34 and against the cutter bar S whereby the cutter bar S may be clampingly secured between the shoulder 48 and the nut 50. Since the adjustment stud is threadably received in bore 44, rotation of the adjustment stud can cause movement of the cutter bar toward or away from knives 9. 
     In order to provide means for both adjusting the position of the central portion of the cutter bar to afford accurate spacing between the central part of the cutter bar and the cutting cylinder and for restraining the center portion of the cutter bar S against slideable movement away from the knives 9, due to the force on the cutter bar generated by the chopping action, a cutter bar guide pin 52 constituting a projection or portion which is rigidly secured to the end of an elongated shiftable member comprised of a cutter bar support rod or shaft 56, which is received within the channel 22 and which has extending ends projecting outwardly beyond the end 22a of the channel 22. The bar S has a bore 55 in its central portion and channel 22 has an opening 54 through its central portion. Projection 52 extends through opening 54 and into bore 55. The elongated support shaft 56 is disposed below cutter bar S and has a longitudinal axis parallel to the cutter bar S and parallel to the longitudinal axis of cylinder C. The elongated support shaft 56 is supported at its outwardly extending end 58 by means for releasably preventing rotation of the shaft and including a generally vertically orientated plate 60 welded or otherwise rigidly secured to the outwardly extending end 58. The vertical plate 60 includes a slot 62 therein spaced from and transverse to the axis of the support rod 56 and a bolt 65 is slideably receivable through slot 62 and threadably received within a bore 64 in a vertical rigid plate 66, in turn welded or the like to the end 22a of the channel 20. The end of the support shaft 56 supporting the guide pin 52 is biased upwardly against the channel 22 by a bolt receivable through a threaded bore 70 in the lower flange 23 of the channel 22. The bolt 68 can be restrained against movement by a pair of lock nuts 72. 
     By rotation of the support rod 56 in a counterclockwise direction, as viewed in FIG. 4, by applying a wrench or the like to the nut 56a welded to the outwardly extending end 58 of the shaft 56, the guide pin 52 can be caused to distort the center portion of the cutter bar S toward the knives 9, and when the plate 60 is then secured against movement, the support rod 56 and guide pin 52 will prevent the center portion of the cutter bar from movement away from the knives 9. Since the central portion of the cutter bar will frequently wear more than its ends, the adjustment feature is particularly useful in affording distortion of the central portion of the cutter bar toward the cutting cylinder to maintain uniform clearance between the cutting cylinder and the cutter bar along its length regardless of uneven wear of the cutter bar. The mechanical elements described above which project outwardly from the side walls 7 and 8 of the forage harvester are readily accessible to the operator, therefore, adjustment of the position of the cutter bar can be accomplished easily.