Abstract:
An improved picker bar assembly for a cotton harvester. The assembly includes a cast arm with an extension which is press fitted over a hollow aluminum picker bar. The extension projects downwardly into the picker bar drum head to provide the wear surface for the picker bar journal and to distribute a greater proportion of picker bar loading to the arm. The spindle drive shaft bearing is located in the cam arm rather than within the picker bar to thereby permit utilization of a larger and higher capacity bearing.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a cotton harvester and more particularly relates to an improved picker bar assembly having a cam follower arm with an extension that projects downwardly into the drum head. 
     In conventional cotton harvesters of the type shown, for example, in U.S. Pat. Nos. 3,245,210 and 4,133,166 to Hubbard, a vertically disposed picker bar is journalled in the drum head of an upright cotton picking unit. Currently available picker bars are fabricated from an aluminum extrusion to reduce mass. The upper end of the bar is keyed and press fitted to a cast cam follower arm, which includes a follower seated in a cam track to properly orient the bar during harvesting. The bar supports a plurality of spindles which are driven by a spindle drive shaft rotatably supported within the bar, in part by a bearing contained within the upper portion of the bar. 
     A principal drawback of the typical prior art design is that the aluminum bar is one of the weakest members of the harvesting unit, and bending or fracturing of the bar or loosening of the cam follower arm can occur when the bar is subjected to abnormally high loading. The size and therefore the capacity of the spindle drive shaft bearing is limited in the prior art construction by the inner diameter of the aluminum bar. 
     It is therefore an object of the present invention to provide an improved cotton picker bar. It is another object to provide such a bar which overcomes the above-mentioned disadvantages of previously available picker bars. 
     It is a further object of the present invention to provide a cotton picker bar which is more resistant to bending and/or fracturing than at least most previously available bars. It is another object to provide such a bar wherein excess loads which would otherwise damage the bar are instead absorbed by the cam arm and drum head. 
     It is yet another object of the invention to provide a cotton picker bar assembly having an improved connection between the cam follower arm and the picker bar to increase strength of the bar and to resist loosening of the cam follower arm even when the bar is subjected to abnormally high loading. It is still a further object of the invention to provide an improved cotton picker bar assembly wherein the size of the spindle drive shaft bearing is not limited by the inner diameter of the aluminum bar. 
     The picker bar assembly of the present invention is constructed such that the cam follower arm has an extended area of press fit over the upper end of the picker bar. The extension of the arm projects downwardly into the drum head and provides a picker bar journal. Any abnormally high load which would otherwise bend or deflect the bar is transmitted into the head and arm. The extension permits placement of a high capacity spindle drive shaft bearing in the cast cam follower arm directly above the upper end of the bar. The extension also provides an increased length of press fit to resist loosening of the cam follower bar on the bar. 
     These and other objects, features and advantages of the present invention will become apparent to one skilled in the art from the description which follows and the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view, partially in section, showing a portion of a row harvesting unit and drive mechanism, with a picker bar assembly typical of the prior art. 
     FIG. 2 is an elevational view, partially in section, of a portion of a row harvesting unit showing the upper portion of the picker bar assembly of the present invention. 
     FIG. 3 is a view similar to FIG. 2 but showing an alternate embodiment of the invention. 
     FIG. 4 is another view similar to FIG. 2 but showing an additional embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring first to the prior art of FIG. 1, therein is shown a portion of a row harvesting unit 10 of a conventional cotton harvester of the type more fully described in the aforementioned Hubbard patents, incorporated herein by reference for background information. The unit 10 includes upper, intermediate and lower horizontal panels 12, 13 and 14, respectively, housing a conventional unit drive, indicated generally at 16, which includes an upright drum shaft 18 extending downwardly through openings in the panels 13 and 14 and connected to a drum head 22. 
     Spaced around the periphery of the drum head 22 are a plurality of bearing surfaces 24. Picker bar assemblies 25, each including a vertical picker bar 26, are journalled in the drum head 22 between the surfaces 24 and bearing caps 28 bolted to the head. Keyed to the upper end of each bar 26 is a cast cam arm or crank 32 which carries on its upper end a cam follower or roller 34. The follower 34 is seated in a cam track (not shown) fixed to the unit housing, and as the drum head 22 is rotated, the picker bars 26 are caused to oscillate about their respective axes 36 to orient picker spindles 38 which are vertically spaced in columns on the bars. The bars 26, which typically are fabricated from aluminum to reduce weight, include removable wear surfaces or sleeves at 42 which are jounalled in the bearings defined in the drum head 22 by the bearing surfaces 24 and the respective bearing caps 28. 
     Each picker bar 26 is hollow and encloses a spindle drive shaft 44 having driving pinions 46 in constant mesh with bevel pinions 48 on the inner ends of the spindles 38. The upper end of the shaft 44 is rotatably supported by a needle bearings 50 contained within the hollow portion of the bar 26, so that the maximum diameter of the bearing 50 is typically approximately equal to the inner diameter of the bar. A spacer 51 is located on the shaft 44 between the bearing 50 and the collar of the upper driving pinion 46 to provide added rigidity to the upper end of the shaft. The shaft 44 extends upwardly through the top of the bar 26. A pinion 52 keyed to the end of the shaft 44 is engaged by a drive gear 54 fixed to a sleeve 56 mounted for rotation about the drum shaft 18. The drum shaft 18 and drive gear 52 are driven in a conventional manner by the unit drive 16 to rotate the picker drum and spindles. Further details of the drive system may be had by reference to the aforementioned Hubbard patents. 
     Referring now to FIG. 2, therein is shown the upper portion of an improved picker bar assembly 60. Below the drum head 22 the assembly 60 is substantially the same as the conventional assembly 25 of FIG. 1. The assembly 60 includes a vertical picker bar 62 having an upper end 64 which projects above the drum head 22. Fixed to the upper end 64 is a cam arm or crank 66 having a downwardly directed extension 68 press fitted onto the bar 62 and extending into the drum head 22. The outer surface of the extension 68 is machined and forms the bearing area for the picker bar journal so that the picker bar 62, which in the preferred embodiment is fabricated from aluminum, does not require a wear sleeve and is not in direct frictional contact with drum head bearing 72 defined by the surface 24 and the cap 28. As seen in FIG. 2, the extension 68 substantially projects through the drum head 22. 
     The cam arm 66 includes a circular bore 74 which receives the upper end 64. However, rather than extending upwardly through substantially the entire length of the bore 74, the end 64 of the bar 62 terminates axially inwardly a substantial distance below the top of the bore and defines therewith a bearing-receiving seat 76. A high capacity roller bearing 78 includes an outer race 82 secured within the seat 76 of the bore 74 by a snap ring 84 inserted in an annular groove 86. An inner race 88 supports the spindle drive shaft 44 for rotation about the axis 36. 
     Key means including a key 90 inserted in keyways 92 and 96 in the bar 62 and arm 66, respectively, prevent relative rotation between the bar and arm. Preferably, the key 90 extends between the bottom of the bearing 78 and the top portion of the extension 68. The extension 68 provides a long length of press fit between the arm 66 and the bar 62 while permitting the high capacity roller bearing 78 to be utilized on the drive shaft 44. 
     A grease seal 102 is provided between the top of the drum head 22 and the bottom of the cam arm 66 adjacent the extension 68. A lower O-ring 104 is held within an annular groove 106 located in the lower portion of the drum head bearing 72. The seal 102 and O-ring 104 prevent dirt and other contaminants from entering the journal area and maintain lubricant between the outer wear surface of the extension 68 and the bearing 72. 
     The embodiment shown in FIG. 3 is similar to that of FIG. 2 except that the upper end 64a of the bar 62a extends through to the upper end of the cam arm bore 74, and the conventional bearing arrangement of FIG. 1 with a needle bearing 50 is provided within the hollow portion of the bar. The area of contact between the arm 66 and the bar 62a is thereby increased, and a longer key 90a is provided. 
     In yet another embodiment (FIG. 4), the cam arm 66a includes an extension 68a which terminates axially within the drum head bearing 72a between the top and the bottom of the drum head 22a. The bore 112 of the bearing 72a formed by surface 24a and bearing cap 28a is stepped at 114 below end 116 of the extension 68a to provide an annular grease reservoir 118. A aperture 122 in the bar 62 permits lubricant to flow from the hollow central portion of the bar to the reservoir 118. A picker bar bushing 126 extends axially downwardly from the stepped portion 114 to provide a wear surface between picker bar 62 and the lower portion of the bearing 72a. 
     Having described the preferred embodiment, it will be apparent that modifications can be made without departing from the scope of the invention as defined in the accompany claims.