Abstract:
To reduce destructive effects of cotton picker high speed drum rotation, rearward spindle tip motion is adjusted in part by angularly positioning the spindles in the picking zone with an improved cam track arrangement. The cam rotates the picker bar about the upright axis of the bar to vary the speed of the spindle tip in the picking zone and allow a higher drum speed. In a first portion of the picking zone the spindle tips are closer together than the spindle bases at the picker bar. The spindle tip spacing in a second portion of the picking zone is approximately equal to spindle base spacing in the extremities. The resulting spindle tip movement facilitates higher cotton picker vehicle ground speed without picking efficiency loss or additional damage to the cotton plants.

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to cotton pickers and, more specifically, to the harvesting drum on a cotton picker row unit. 
   BACKGROUND OF THE INVENTION 
   A typical spindle-type cotton picker includes upright cotton picker drums with bars or columns of rotating spindles that engage the cotton plants. The drums are rotated so the rearward motion of the spindles in the picking zone is synchronized to the forward speed of the picker to generally obtain zero relative velocity between the cotton plant and the spindles engaging that cotton plant. 
   The picker drums present a large mass in motion with numerous rotating parts and therefore have a limited rotational speed. The drum speed limitation dictates the maximum harvest speed of the picker. Attempts to increase picker speed have concentrated on reduction of drum mass, better lubrication of the rotating elements that experience increased friction with increased speed, and minimization of acceleration of mass as the columns of spindles are oriented by a by picker bar cam arm and a cam track. 
   Previously available row units using the drum circumferential speed to achieve the synchronization also included a cam track that angularly positioned the spindles to move the tips of the spindles closer in the picking zone. This angular positioning of the spindles increased the spindle density in the picking zone but actually compromised spindle/plant synchronization in the zone since the effect of decreasing spacing was to slow the rearward speed of spindles in the zone. The spindle tips moved more slowly than their bases generally throughout the entire picking zone, and in an aft portion of the zone the spindle tip velocity decreased even more. Therefore, forward harvester speed was limited by the slowing of the spindles in the picking zone. 
   SUMMARY OF THE INVENTION 
   The present invention reduces destructive effects of cotton picker high rotational drum speed by more closely synchronizing the rearward spindle tip motion with the forward speed of the cotton picker, in part by use of improved angular positioning the spindles in the picking zone. An improved cam track arrangement of the present invention angularly positions the spindles so that spindle tip spacing in a substantial portion of the picking zone is equal to spindle base spacing in the extremities to thereby maintain closer plant/spindle synchronization over a substantial portion of the zone. Only in one portion of the picking zone are the spindle tips closer together than the spindle bases. Over the remainder of the picking zone, the spindle speed is more closely synchronized to the harvester speed. Rearward spindle tip motion is adjusted by the angular positioning of the spindle bars by the cam arrangement. The cam rotates the picker bar about the upright axis of the bar to vary the speed of the spindle tip in the picking zone and allow a higher drum speed. As a result, a higher cotton picker vehicle ground speed can be achieved without loss of picking efficiency and without any additional damage to the cotton plants that are being picked. In one embodiment, for example, the drum with the improved cam configuration facilitates increases in the maximum harvester speed from about 14% to 25% compared to a conventional cam configuration without loss of picking efficiency or additional damage to the cotton plants being picked. The improved cam configuration also provides smoother picker bar pivoting action to avoid excessive bearing forces and reduce slinging of cotton from the spindles. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top view of a conventional cotton picker row unit. 
       FIG. 2  is an enlarged top view of a portion of the cam track for controlling spindle orientation in the picking zone of one of the drums of conventional unit of  FIG. 1  showing schematically spindle orientation at a plurality of locations in the picking zone. 
       FIG. 3  is a top view of an improved row unit configuration showing the cam track in broken lines. 
       FIG. 4  is a view similar to  FIG. 2  showing the improved cam track of  FIG. 3  and illustrating the improved spindle orientation providing advantageous spindle movement for increased drum speed. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to  FIG. 1  therein is shown a conventional row unit  10  for a cotton picker. The row unit  10  includes a housing  12  with upright structural members such as shown at locations  14 ,  15  and  16 . A fore-and-aft extending row-receiving area  20  is defined which extends rearwardly from between a pair of stalk lifters  22  through to the rear of the housing  12 . Front and rear upright picker drums  26  and  27  with upright rotational axes  28  and  29  are supported within the housing  12  and include spindles  30  supported in rows by a plurality of upright spindle or picker bars  32 . The spindles  30  include rows of barbs (not shown) extending generally in the direction of rotation of the spindles. The picker bars  32  are supported for rotation about upright axes such as shown at  36  in  FIG. 3  uniformly spaced about a circle C 1  of radius R 1  which centers on the rotational axis  28  of the drum. Each picket bar  32  includes a cam arm  38  with an upper cam roller  40  supported within the track of a cam  42  or  43  for the drum  26  or  27 , respectively, which orients the bars  32  for the desired spindle position as the drum rotates about its upright axis. The spindles enter a picking zone  20   a  ( FIGS. 1 and 2 ) in the row-receiving area  20  in first and second drum rotation quadrants Q 1  and Q 2  in the counterclockwise direction from the forwardmost extremity of the drum. 
   Doffer columns  48  and  49  are supported for rotation about upright axes  50  and  51  parallel to and rearwardly and outwardly of the corresponding drum axes  28  and  29  (i.e., in the third quadrant Q 3  from the forwardmost extremity of the drum) for doffing cotton from the spindles. Supported adjacent the forwardmost extremities of the drums  26  and  27  (in the fourth quadrant Q 4 ) are upright moistener columns  52  and  53 , each with spindle-wiping pads  54  connected to a nozzle and distribution system located within the housing  12  for wiping the spindles  30  after cotton is doffed therefrom. The rear drum  27  is spaced a sufficient distance rearwardly of the forward drum  26  so that the path of the spindles  30  of the forward drum  26  does not intersect the rear moistener column  53 . 
   A conventional drive mechanism including a spindle drive  58  (see  FIG. 3 ) rotates the drums, spindles and doffers. As the drums  26  and  27  rotate in the counterclockwise direction as viewed in  FIG. 1  through four quadrants (Q 1 -Q 4 ) starting with the forwardmost portion of the drum, the path of the spindles  30  is controlled by the cam arm  38 , roller  40  and track  42  so that the spindles project into the row-receiving area  20   a  through grid bars  64  and  65  (quadrants Q 1  and Q 2 ) as the drive  58  rotates the spindles  30  in contact with the cotton in a picking zone  20   a . As shown in the drawings, the row unit  10  is an in-line unit with the drums and drum axes on one side only of the row-receiving area so that cotton is picked from one side of the plant. Pressure plates  66  and  67  urge the plants inwardly toward the spindles  30 . The cotton-wrapped spindles  30  are moved under the doffers of the doffer columns  48  and  49  in the quadrant Q 3 , and cotton is doffed from the spindles and directed rearwardly and outwardly to door structure  70  to be conveyed to the harvester basket (not shown). 
   As seen in  FIG. 1 , the cams  42  and  43  are elongated in the fore-and-aft direction and have elongate axes  72  and  73 . The cams  42  and  43  have a comma-shaped configuration with abrupt or relatively sharp changes of direction at the tail or rearmost portion  76 . As the drums rotate, the cam configuration causes the spindle bar near the rear of the drum to accelerate quickly and rotate about the bar axis through a transition area (between the row-receiving area and the doffer column) and into a position wherein the doffers can start to unwind cotton from the spindles  32 . After the cotton is doffed and the spindles move into the fourth quadrant Q 4 , the cams accelerate the spindles quickly for reentry into the row receiving area  20 . In the same quadrant Q 4 , the spindles pass through the moistener column. As the spindles  30  contact the pads  54  of the moistener column and begin to be reoriented for entry into the row-receiving area, the axes of the spindles are angled forwardly with respect to the leading and trailing edges of the pads. 
   The path and orientation of the spindle axes  30   a  in the picking zone  20   a  for the unit of  FIG. 1  is shown schematically in  FIG. 2 . The picking zone  20   a  is defined generally as the area wherein the spindles  30  project approximately one inch (2.5 cm) or more through the grid bars into the cotton plants passing rearwardly relative to the drum. At the first or leading portion of the zone  20   a  the spindles project generally perpendicularly to the forward direction F of travel of the harvester. At the leading portion of the zone  20   a , the rearward speed of spindle tip is approximately equal to but slightly less than the forward harvester speed. As the spindle moves rearwardly in the zone, the cam track  42  continually angles the spindle axes  30   a  in the forward direction effectively slowing the rearward speed of the spindles  30  so that spindle tip speed slows even more relative to harvester speed. The effective slowing of the fore-and-aft speed of the spindle further reduces synchronization. At the rearward portion of the picking zone  20   a , spindle tip spacing in minimized, spindle density is maximized, and spindle to plant synchronization is reduced to the lowest level within the picking zone. 
   Referring now to  FIGS. 3 and 4  therein is shown an improved drum arrangement wherein the cam tracks  42   b  and  43   b  for drums  26   b  and  27   b  are reconfigured to provide improved plant engagement and synchronization of the plants and the spindles  30  projecting through the grid bar  64 ′ into the plants in an elongated picking zone  80 . The tracks  42   b  and  43   b  pivot the upright bars  32  to angle the spindle axes  30   a  rearwardly and increase spindle density in a first portion  81  of the zone. The bunching of the spindle tips  30   t  tends to decrease the rearward speed of the spindles  30  relative to the drum when the spindles are in the first portion  81  of the picking zone. 
   In a second portion  82  of the picking zone  80 , the cam tracks  42   b  and  43   b  pivot the spindles so the spindle axes  30   a  are generally parallel to maintain the rearward speed of spindle tips  30   t  approximately equal to the rearward speed of the corresponding spindle bases  30   b . The spindle axes  30   a  in the second portion  82  are generally transverse to the forward direction F. When the spindles  30  are in the second portion  82  of the zone  80 , the speed of the spindle tip  30   t  more closely approximates the drum periphery speed and better matches the rearward speed of the plant relative to the row unit. The cam track configuration provides increased spindle density in the first portion  81  of the picking zone  80  and more closely approximates zero velocity between the spindles  30  and the plants engaged by the spindles in the second portion  82 . The increased spindle density at the forward portion of the zone  80  assures good spindle contact with a substantial portion of the cotton plant to initiate engagement of the spindle barbs with the cotton bolls. The parallel and transverse spindle orientation in the aft portion  82  of the picking zone  80  provides excellent spindle engagement and cotton removal from the plants. A reverse curve in the cam track at  42   r  in the quadrant Q 2  provides a smooth spindle transition out of the aft portion of the picking zone  80  in preparation for movement of the cotton wrapped spindles into the doffing zone adjacent the doffer  48 . The configuration of the cam track  43   b  and spindle orientation for the rear drum  27   b  is similar to that described above for the forward drum  26   b  and will not be described in further detail here. 
   As can best seen by comparing  FIG. 4  and the prior art configuration of  FIG. 2 , the cam track  42   b  is curved more outwardly at a first cam track portion  101  relative to the circle C 1  of the spindle bars in quadrant Q 1 . The increased outward bowing of the first cam track portion  101  causes the spindle bars to pivot the spindles  30  towards the rear so that the spindle axes  30   a  in the first portion  81  of the zone are angled rearwardly towards the second portion  82  with respect to a direction transverse to the forward direction. The spindle tips  30   t  move more closely to each other, and the spindle tip spacing is less than the spindle base spacing for the spindles in the first portion  81 . 
   The cam track  42   b  curves radially inwardly and crosses the circle C 1  near the intersection of the quadrants Q 1  and Q 2  to a juncture with a second cam track portion  102 . As the cam roller  40  follows the cam track portion  102 , the picker bars are rotated about their upright axes to position the spindle axes  30   a  in a parallel relationship in the picking zone portion  82 . The bar rotation also increases the rearward velocity of the spindle tips  30   t . In the zone  82 , the spacing of the spindle tips  30   t  is approximately equal to the spacing of the corresponding spindle bases  30   b.    
   The cam track  42   b  includes a third portion  103  which gently curves radially outwardly to smoothly pivot the spindle bar  32  in the counterclockwise direction as viewed in  FIG. 3 . The third portion  103  is directly above a lowermost portion  104  of the comma shaped cam track configuration at the juncture of the second and third quadrants Q 2  and Q 3 . As the cam track crosses the circle C 1  at the portion  104 , the spindles are oriented with respect to the doffer column  48  for removal of the cotton from the spindle. 
   Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.