Patent Publication Number: US-10327372-B2

Title: Mounting structure for mounting gauge wheel assembly to implement

Description:
RELATED APPLICATION 
     This application claims the priority benefit of U.S. Provisional Patent Application No. 62/263,528 filed on Dec. 4, 2015, the content of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates generally to seed planting implements, and in particular, to an improved mounting structure for mounting gauge wheel arms and closing wheel arms to a seed planting implement. 
     Description of the Related Art 
     In approximately 1974 John Deere introduced its Max Emerge Model 7000 planter, which included gauge wheels that carry the weight of the row unit, and gauge wheel arms that supported the offset loads of the gauge wheels. Because of the way the offset loads are supported by the gauge wheel arms, the durability of the gauge wheel arms and their pivot mounting was poor. The ground load on the gauge wheel is offset from the center of the row where the arm pivots upward and engages an adjustable stop. 
     Because of the offset load the arm is always trying to lean sideways. The load then is supported by two points of contact between the pivot pin and the bore of the hub. One point is on top of the pin at the inner end of the hub, and the other point is on the bottom of the pin at the outer end. These two points of contact are small and highly loaded. Because of the oscillating motion, grease gets squeezed out of these two points of contact and does not get carried back into them. 
     As a result the two points of contact are bound to wear. As they wear the arm leans allowing the tire to pull away from the opener disk. This eventually allows moist soil sticking to the disk to be carried up into the space between the wheel and opener disk. A scraper removes the soil from the disk which then can accumulate and plug this space. The same plugging can occur with trash. 
     In 1994, the Applicant introduced a gauge wheel arm mounting assembly that used a disc spring (Belleville Washer) to support the offset load. This gauge wheel arm mounting assembly is illustrated in FIGS. 5, 6 and 7 of Applicant&#39;s U.S. Pat. No. 5,904,107. Shims were used to set the spring pressure. 
     After one year it was apparent that a simpler method of adjusting the spring pressure was needed. A threaded adjustment was then developed by the Applicant, which is shown in FIGS. 8 and 9 of U.S. Pat. No. 5,904,107. This threaded adjustment later evolved into an attaching method shown in Applicant&#39;s Instruction Sheet AI-1250. Item K in instruction sheet AI-1250 is an adjusting stud assembly. The adjusting stud is machined from bar stock and has a tapped hole. The attaching stud is a threaded stud screwed into the tapped hole. The attaching stud is fixed within the adjusting stud using, for example, a thread adhesive compound. The attaching stud is screwed into the tapped hole in the end of the fixed pivot pin (not shown). 
     Disc spring pressure is adjusted by a nylon insert locknut J. Properly installed a force of approximately 1500 lbs. is applied to the ends of the hub. This is more than required to prevent the arm from leaning but it can still pivot freely. Because the arm cannot lean the pressure on the ends of the hub is evenly distributed around the circle of contact which is a big area. This results in the wear almost being eliminated. The result is that the tire can be adjusted to stay in contact with the opener disk indefinitely. Adjusting washers at each end of the hub are used to establish the proper relationship between the tire and opener disk. 
     In 1997, the John Deere Model 1700 planter model was introduced. The gauge wheel arm pivot incorporated a threaded bushing which allowed the arm to be moved in or out simply by loosening a bolt and turning the threaded bushing. No adjusting washers are needed. This gauge wheel arm pivot assembly is illustrated in FIGS. 2 and 3 of U.S. Pat. No. 5,427,038. 
     To use the RKP gauge wheel arm pivot kit with the Model 1700 planter, it was necessary to replace the threaded bushing with a split bushing F, as illustrated in Applicant&#39;s Instruction Sheet AI-1251. 
     In 2014, the John Deere Model MaxEmerge 5 (ME5) planter row unit was introduced, which included a redesigned gauge wheel arm. The redesigned gauge wheel arm still provides a threaded feature for adjusting the position of the gauge wheels. It also has a bearing surface at each end of the bore of the hub. The gauge wheel arm mounting assembly for the Model ME5 planter is illustrated in FIGS. 2 and 3 of U.S. Pat. No. 8,387,715. 
     In 1998, the disc spring design used on planter gauge wheel arm pivots was adapted to the early John Deere Model 750 no-till drills, as shown on Applicant&#39;s Instruction Sheet AI-1240. This drill did not have sleeve bearings and it was very impractical to try to repair it. The problem of wear on the pivot was very similar to that of the planter gauge wheel arm pivot. 
     The Applicant&#39;s disc spring design was successfully used in the Model 750 drills, and was later adapted to the other model drills, as shown in Applicant&#39;s Instruction Sheet AI-1242. 
     However, there is still a need for an improved mounting structure for mounting a pivot arm, such as a gauge wheel arm or a closing wheel arm, to an implement. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an improved mounting structure for mounting a pivot arm, such as a gauge wheel arm or a closing wheel arm, to an implement. 
     A further object of the present invention is to provide a mounting structure for mounting a pivot arm to a seed planting implement, which creates a lateral bearing force against a bearing housing. 
     A further object of the present invention is to provide a mounting structure for mounting a pivot arm to a seed planting implement, which can be retrofit to existing implements. 
     To accomplish these and other objects of the present invention, a mounting structure is provided for mounting a pivot arm to an implement, which has a cylindrical member, an adjusting sleeve, and a mounting bolt extending through the cylindrical member and adjusting sleeve to fix the cylindrical member and adjusting sleeve together. The cylindrical member extends through a bore of a bearing housing for rotation relative to the bearing housing. The adjusting sleeve has a threaded external surface. A disc spring is positioned on the adjusting sleeve. An adjusting nut is threaded onto the threaded external surface of the adjusting sleeve. The adjusting nut can be tightened to compress the disc spring to create a lateral bearing force against the bearing housing. The bearing housing can be integral with a pivot arm for mounting a gauge wheel assembly on a planter row unit, or the bearing housing can be a fixed part for mounting a pivot arm for a closing/press wheel on a drill. 
     According to one aspect of the present invention, a row unit is provided for an implement, comprising: a frame; a gauge wheel assembly; a pivot arm having a first end coupled to the gauge wheel assembly and a second end comprising a hub for pivotally mounting the pivot arm to the frame, the hub having a bore therethrough; a cylindrical member having an inner end and an outer end, the cylindrical member extending through the bore of the hub with the inner end of the cylindrical member adjacent to the frame and the cylindrical member being coaxial with the bore of the hub; an adjusting sleeve having an outer end, an inner end, an inner bore, and a threaded outer surface, the adjusting sleeve being positioned coaxial with the cylindrical member with the inner end of the adjusting sleeve adjacent to the outer end of the cylindrical member; a mounting bolt having a head at one end, the bolt extending through the inner bore in the adjusting sleeve with the bolt head adjacent to the outer end of the adjusting sleeve and a threaded portion of the bolt extending beyond the inner end of the adjusting sleeve for insertion into a female threaded portion of the cylindrical member or the frame, the mounting bolt being threaded into the female threaded portion and tightened to fix the cylindrical member and adjusting sleeve to the frame while allowing rotation of the hub and pivot arm about the cylindrical member; at least one disc spring positioned on the adjusting sleeve; and a nut threaded onto the threaded outer surface of the adjusting sleeve, the nut compressing the disc spring to restrain the hub on the cylindrical member such that compression of the disc spring creates a lateral bearing force on the hub which is transferred to the frame. 
     According to another aspect of the present invention, a mounting structure is provided for mounting a gauge wheel assembly to a frame of a row unit of an implement, the mounting structure comprising: a pivot arm having a first end adapted to be coupled to a gauge wheel assembly and a second end comprising a hub for pivotally mounting the pivot arm to the frame, the hub having a bore therethrough; a cylindrical member having an inner end and an outer end, the cylindrical member extending through the bore of the hub with the inner end of the cylindrical member adjacent to the frame and the cylindrical member being coaxial with the bore of the hub; an adjusting sleeve having an outer end, an inner end, an inner bore, and a threaded outer surface, the adjusting sleeve being positioned coaxial with the cylindrical member with the inner end of the adjusting sleeve adjacent to the outer end of the cylindrical member; a mounting bolt having a head at one end, the bolt extending through the inner bore in the adjusting sleeve with the bolt head adjacent to the outer end of the adjusting sleeve and a threaded portion of the bolt extending beyond the inner end of the cylindrical member for insertion into a female threaded portion of the cylindrical member or the frame, the mounting bolt being threaded into the female threaded portion and tightened to fix the cylindrical member and adjusting sleeve to the frame while allowing rotation of the hub and pivot arm about the cylindrical member; at least one disc spring positioned on the adjusting sleeve; and a nut threaded onto the threaded outer surface of the adjusting sleeve, the nut compressing the disc spring to restrain the hub on the cylindrical member such that compression of the disc spring creates a lateral bearing force on the hub which is transferred to the frame. 
     Numerous other objects of the present invention will be apparent to those skilled in this art from the following description wherein there is shown and described example embodiments of the present invention. As will be realized, the invention is capable of other different embodiments, and its several details are capable of modification in various obvious aspects without departing from the invention. Accordingly, the drawings and description should be regarded as illustrative in nature and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more clearly appreciated as the disclosure of the present invention is made with reference to the accompanying drawings. In the drawings: 
         FIG. 1  is a side view of a planter row unit having a gauge wheel assembly with a pivot arm attached to the row unit frame with a mounting structure according to a first embodiment of the present invention. 
         FIG. 2  is an exploded perspective view of the pivot arm with a threaded member at one end for attaching a gauge wheel to the pivot arm, and a hub at the other end for attaching the pivot arm to the row unit frame. 
         FIG. 3  is an exploded perspective view of the pivot arm and other components of the mounting structure of the first embodiment of the present invention. 
         FIGS. 4, 5 and 6  illustrate a pivot arm mounting structure according to the first embodiment of the present invention, which uses a long bolt threaded into a threaded opening in the row unit frame.  FIGS. 4 and 5  are exploded perspective views showing the two different types of sleeve bearings that can be used, and  FIG. 6  is an exploded perspective view of the pivot arm mounting structure according to the present invention. 
         FIGS. 7, 8 and 9  illustrate a pivot arm mounting structure according to the first embodiment of the present invention, which uses a pivot pin fixed on the row unit frame.  FIGS. 7 and 8  are exploded perspective views showing the two different types of sleeve bearings that can be used, and  FIG. 9  is an exploded perspective view of the pivot arm mounting structure according to the present invention. 
         FIG. 10  is an exploded perspective view of a pivot arm and mounting structure for attaching a closing wheel to a no-till grain drill implement according to a second embodiment of the present invention. 
         FIG. 11  is an exploded perspective view of the pivot arm and other components of the mounting structure, according to an alternative embodiment in which a heat treated sleeve bearing having an enlarged section at one end is slipped into the hub and held in place with a retaining compound. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A mounting structure  10  for mounting a gauge wheel pivot arm  11  to a planter row unit  12  according to a first embodiment of the present invention will be described in detail with reference to  FIGS. 1 to 9  of the accompanying drawings. 
     An agricultural planter row unit  12  is illustrated in  FIG. 1 . The row unit  12  is attached to a transverse toolbar  13  in a conventional manner. The row unit  12  has a frame  14  coupled to the toolbar  13  by a parallel linkage  15  to allow vertical movement of the row unit  12  relative to the toolbar  13 . A seed meter  16  singulates seed from a seed pool in the seed hopper  17  and drops the seeds through a seed tube  18  into a planting furrow. The furrow is formed in the soil by a furrow opener having pair of closely spaced opener disks  19 . 
     Gauge wheels  20  control the depth of the furrow and are mounted to the frame  14  by respective pivot arms  11 . One gauge wheel  20  is adjacent to the outer side of each opener disk  19 . 
     The frame  14  has a threaded hole  33  on each side for mounting the pivot arms  11  to the frame  14 . The pivot arms  11  each have a first end  22  coupled to the gauge wheel  20 , and a second end with a hub  23  for pivotally mounting the pivot arm  11  to the frame  14 . 
     The hub  23  has a bore  24  therethrough into which an oversize sleeve bearing, such as a split bushing  25 , is pressed. The split bushing  25  has an inner bore  26  and a longitudinal split  27 . The longitudinal split  27  allows the split bushing  25  to be pressed into the bore  24  of the hub  23 . 
     In an alternative embodiment, as illustrated in  FIG. 11 , a heat treated sleeve bearing  25 A having an enlarged section  25 B at one end can be slipped into the hub  23  and held in place with a retaining compound, such as a two-part epoxy material. The sleeve bearing  25 A in this embodiment is shaped to fit snugly into the hub bore  24  of a late model John Deere planter in which the hub bore  24  is only partially threaded and has an enlarged bore section at one end. 
     Two variations of the mounting structure  10  according to the first embodiment of the invention are illustrated in  FIGS. 2 to 9 . The first variation is illustrated in  FIGS. 2 to 6  and uses a long bolt  41  that passes through the mounting structure and is threaded into the threaded hole  33 . A cylindrical member in the form of a bushing  29  extends through the bore  26  of the sleeve bearing  25  within the hub bore  24 . The outer surface of the bushing  29  provides the bearing surface that engages the inner bore  26  of the sleeve bearing  25 ,  25 A to allow the arm  11  to rotate relative to the frame  14 . 
     The bushing  29  in the variation illustrated in  FIGS. 2 to 6  has a cylindrical body with an inner end  30 , an outer end  31 , and a through bore  32 . The bushing  29  extends through the bore  24  of the hub  23  with the inner end  30  of the bushing  29  adjacent to the frame  14 , and the through bore  32  of the bushing  29  coaxial with the threaded hole  33  in the frame  14 . The outer surface  34  of the bushing  29  provides a bearing surface that engages the inner bore  26  of the sleeve bearing  25  to allow rotation of the hub  23  about the bushing  29 . The bushing  29  remains fixed relative to the frame  14  once the bolt  41  is tightened. 
     The second variation is illustrated in  FIGS. 7 to 9  and uses a pivot pin  70  fixed to the threaded hole  33  on the row unit frame  14 . A shorter bolt  71  passes through a portion of the mounting structure into a threaded portion  72  at the outer end  73  of the pivot pin  70 . In this variation, the outer surface  74  of the pivot pin  70  is a cylindrical member that provides a bearing surface that engages the inner bore  26  of the sleeve bearing  25 ,  25 A to allow the arm  11  to rotate relative to the frame  14 . 
     The pivot pin  70  in the variation illustrated in  FIGS. 7 to 9  has an inner end  75  with an inner bore (not shown) with female threads that receive a threaded stud (not shown). The threaded stud is threaded into the threaded hole  33  to fix the pivot pin  70  to the frame  14 . Alternatively, the pivot pin  70  can have an integral male threaded portion extending from its inner end  75  for mating with the female threads of the threaded hole  33  to fix the pivot pin  70  to the frame  14 . 
     An adjusting sleeve  35  is positioned coaxial with the bushing  29  or the pivot pin  70 . The adjusting sleeve  35  has an outer end  36 , an inner end  37 , an inner bore  38 , and a threaded external surface  39 . The inner end  37  of the adjusting sleeve  35  is adjacent to the outer end  40  of the housing  23  and abuts with the outer end  31  of the bushing  29  or the outer end  73  of the pivot pin  70 . The inner bore  38  of the adjusting sleeve  35  is a smooth bore. 
     The mounting bolt  41  in  FIGS. 2 to 6  extends through the inner bore  38  of the adjusting sleeve  35  and the through bore  32  in the bushing  29 . The mounting bolt  41  has a head  42  at one end adjacent to the outer end  36  of the adjusting sleeve  35 . A first washer W 1  ( FIG. 6 ) can be positioned between the head  42  of the bolt  41  and the outer end  36  of the adjusting sleeve  35 . A second washer W 2  ( FIG. 6 ) can be positioned between the inner end  37  of the adjusting sleeve  35  and the outer end  31  of the bushing  29 . A threaded portion  43  of the mounting bolt  41  extends beyond the inner end  30  of the bushing  29  for insertion into the threaded hole  33  in the frame  14 . The mounting bolt  41  is threaded into the threaded hole  33  and tightened to fix the bushing  29  and adjusting sleeve  35  to the frame  14 , while allowing rotation of the hub  23  and pivot arm  11  about the bushing  29 . For example, the bolt  41  can be tightened to a torque of approximately 200 ft-lbs. 
     The mounting bolt  71  in  FIGS. 7 to 9  extends through the inner bore  38  of the adjusting sleeve  35  and has a threaded portion  76  that mates with the threaded portion  72  at the outer end  73  of the pivot pin  70 . The mounting bolt  71  has a head  77  at one end adjacent to the outer end  36  of the adjusting sleeve  35 . A first washer W 1  can be positioned between the head  77  of the bolt  71  and the outer end  36  of the adjusting sleeve  35 . A second washer W 2  can be positioned between the inner end  37  of the adjusting sleeve  35  and the outer end  73  of the pivot pin  70 . The mounting bolt  71  is threaded into the threaded portion  72  of the pivot pin  70  and tightened to fix the adjusting sleeve  35  to the pivot pin  70  and the frame  14 , while allowing rotation of the hub  23  and pivot arm  11  about the pivot pin  70 . For example, the bolt  71  can be tightened to a torque of approximately 200 ft-lbs. 
     At least one disc spring  44  is positioned on the adjusting sleeve  35 . A selected number of first adjusting washers  45  are positioned on the bushing  29  or the pivot pin  70  between the inner side  46  of the hub  23  and the frame  14 . A selected number of second adjusting washers  47  are positioned on the bushing  29  or the pivot pin  70  between the outer end  40  of the hub  23  and the disc spring  44 . 
     The adjusting sleeve  35  has at least one keyway  48 , and preferably two keyways, on its external surface  39 . A tab washer  49  is positioned on the adjusting sleeve  35  between the second adjusting washers  47  and the disc spring  44 . The tab washer  49  has at least one tab  50 , and preferably two tabs, mated with the keyway(s)  48  on the adjusting sleeve  35 . The tab washer  49  minimizes relative rotation and resulting wear between the disc spring  44  and the tab washer  49 . 
     A nut  51  is threaded onto the threaded external surface  39  of the adjusting sleeve  35 . The nut  51  preferably comprises a locknut having a nylon insert to prevent the nut from loosening on the adjusting sleeve  35  during use. The nut  51  is tightened to compress the disc spring  44  to restrain the hub  23  on the bushing  29  or the pivot pin  70 . Compression of the disc spring  44  creates a lateral bearing force on the hub  23  which is transferred to the frame  14 . 
     The first end  22  of the pivot arm  11  has a tapped hole  52 . A second bolt  53  is threaded into the tapped hole  52  with a head  54  of the second bolt  53  adjacent to an inner side  55  of the pivot arm  11 . The head  54  of the second bolt  53  is thinner (e.g., approximately ¼ inch) than a standard bolt head to prevent contact of the head  54  with the adjacent opener disk blade  19 . A free end  56  of the second bolt  53  extends outwardly from an outer side  57  of the pivot arm  11 . The second bolt  53  is tightened within the tapped hole  52  of the pivot arm  11  to a torque of approximately 50 ft-lbs. 
     Alternatively, the second bolt  53  can be a threaded stud without a head to ensure that the bolt will not protrude from the inner side of the pivot arm  11  and interfere with the adjacent opener disk blade  19 .  FIG. 3  illustrates a second bolt  53  in the form of a threaded stud without a head protruding on the inner side of the pivot arm  11 . A thread seizing compound, such as Loctite Threadlocker™, can be used on the threaded stud to prevent it from loosening. 
     A selected number of third adjusting members  58 ,  59  are positioned on the second bolt  53  between the gauge wheel assembly  20  and the outer side  57  of the pivot arm  11 . The third adjusting members include a plurality of shims  58  and washers  59  to adjust a lateral position of the gauge wheel assembly  20 . 
     The gauge wheel assembly  20  is placed onto the free end  56  of the second bolt  53 , and a wheel nut  60  is threaded onto the free end  56  of the second bolt  53  to secure the gauge wheel assembly  20  to the pivot arm  11 . 
     The following process can be used to remove the OEM gauge wheel arm from a planter row unit  12  and install the gauge wheel arm pivot assembly  10  of the present invention. 
     The gauge wheel  20  is removed from the pivot arm  11  by removing the OEM axle bolt (not shown) at the center of the gauge wheel  20 , which is threaded into the tapped hole  52  at the end  22  of the pivot arm  11 . 
     The pivot arm  11  is removed by removing the mounting bolt  41  from the threaded hole  33  in the frame  14 . A threaded OEM bushing (not shown) is removed from the hub  23  and can be discarded. If necessary, the ends  40 ,  46  of the hub  23  can be filed to make sure they are smooth and flat and free of excessive paint. Care should be taken to make sure that the adjusting washers  45 ,  47  will lay flat on the inner end  46  of the hub  23 . If the pivot arm  11  interferes with the adjusting washers  45 ,  47  laying flat, the interference can be eliminated by grinding. 
     The split bushing  25  is then pressed into the bore  24  of the hub  23 . As described above, the split bushing  25  can have an alternative configuration  25 A as needed to fit snugly within the bore  24  of the hub  23 . 
     The second bolt  53  is threaded into the tapped hole  52  at the first end  22  of the pivot arm  11  until its head  54  is tight against the inner surface  53  of the pivot arm  11 . The second bolt  53  is tightened to a torque of approximately 50 ft-lbs. Alternatively, a threaded stud can be threaded into the tapped hole  52  and secured in position by a suitable thread seizing compound, such as Loctite Threadlocker™. 
     The pivot bushing  29  or the pivot pin  70  is inserted into the bore  26  of the sleeve bearing  25 ,  25 A. The locknut  51  is installed onto the adjusting sleeve  35  flush with the outer end  36  of the adjusting sleeve  35 , as shown in  FIG. 6 . The disc spring  44  and tab washer  49  are installed onto the adjusting sleeve  35 . The mounting bolt  41  ( FIGS. 2 to 6 ) is then installed through the adjusting sleeve  35 , the pivot bushing  29 , and the remaining parts as shown and into the threaded hole  33  in the frame  14 , or the mounting bolt  71  ( FIGS. 7 to 9 ) is installed through the adjusting sleeve  35  and the remaining parts as shown and into the threaded portion  72  of the pivot pin  70 . 
     Adjusting washers  45 ,  47  are used to adjust the clearance between the pivot arm  11  and the gauge wheel assembly  20  and the opener disk  19 . A few shims  58  can also be used to position the gauge wheel  20  properly on the pivot arm  11 . The adjusting washers  45 ,  47  should be lubricated with a light coating of oil. 
     The mounting bolt  41 ,  71  can then be tightened to a torque of approximately 200 ft-lbs. The pivot arm  11  should still be loose for rotation on the bushing  29  or the pivot pin  70  after the mounting bolt  41 ,  71  is tightened. 
     Several washers  59  are then placed onto the second bolt  53 , and the gauge wheel  20  is loosely placed onto the bolt  53 . The locknut  51  is then tightened to increase the disc spring  44  pressure on the hub  23  of the arm  11  to the point that when the wheel  20  is raised it will just stay up. It should take a small force to push the wheel  20  down, and care should be taken not to over-tighten the locknut  51 . The wheel  20  should be kept high enough that it does not interfere with the bearing housing of the opener disk  19 . 
     The wheel nut  60  is threaded onto the second bolt  53  to hold the wheel  20  on the pivot arm  11 . The number of shims  58  and washers  59  can be adjusted to obtain a light pressure between the tire of the gauge wheel assembly  20  and the opener disk  19 . The pressure should be just high enough that when the wheel  20  is turned by hand the opener disk  19  will also turn. When planting with the row unit  12 , the ground load will cause the opener disk  19  to flex inward slightly and the tire of the gauge wheel assembly  20  to flex outward slightly. The pressure between the tire  20  and the opener disk  19  will be reduced during actual planting due to the flexing caused by the ground load. 
     The mounting structure  10  of the present invention, when properly installed, will result in the opener disks  19  being cleaned by the tires of the gauge wheel assembly  20 . This may allow the OEM scrapers for the opener disks  19  to be eliminated from the row unit  12 . 
     A mounting structure  100  for mounting a closing wheel pivot arm  101  to a no-till agricultural seeding drill according to a second embodiment of the present invention will now be described in detail with reference to  FIG. 10  of the accompanying drawings. The mounting structure  100  is used to rotatably mount the closing wheel arm  101  to a bearing housing  102  on the drill. 
     The bearing housing  102  has a first side  103 , a second side  104 , and a bore  105  extending therethrough. A pair of grooved sleeve bearings  106 ,  107  are fixed within the bore  105  of the bearing housing  102 . The sleeve bearings  106 ,  107  each have an inner bore  108  that provides a bearing surface. A pair of seals  109 ,  110  are installed on each side of the bearing housing  102  to keep dirt out of the bearing housing  102 . 
     The pivot arm  101  has a first end  111  coupled to a rotatable closing wheel  112  and a second end  113  coupled to the bearing housing  102  by the mounting structure  100 . A spring  114  is used to bias the pivot arm  101  downward to transfer down force from the implement to the closing wheel  112 . 
     A bushing  115  extends through the inner bores  108  of the sleeve bearings  106 ,  107  within the bore  105  of the bearing housing  102 . The bushing  115  has a cylindrical body with an inner end  116 , an outer end  117 , and a through bore  118 . The bushing  115  extends through the bore  105  of the bearing housing  102  with the outer end  118  of the bushing  115  adjacent to the second side  104  of the bearing housing  102 , and the inner end  116  of the bushing  115  adjacent to the second end  113  of the pivot arm  101 . The outer surface of the bushing  115  provides a bearing surface that engages the inner bores  108  of the sleeve bearings  106 ,  107  to allow rotation of the bushing  115  within the bearing housing  102 . 
     An adjusting sleeve  119  is positioned coaxial with the bushing  115 . The adjusting sleeve  119  has an outer end  120 , an inner end  121 , an inner bore  122 , and a threaded external surface  123 . The inner end  121  of the adjusting sleeve  119  is adjacent to the outer end  117  of the bushing  115 . 
     A mounting bolt  124  extends through a bore  125  in the second end  113  of the pivot arm  101  and the through bore  118  in the bushing  115  and the inner bore  122  in the adjusting sleeve  119 . The mounting bolt  124  has a head  126  at one end and a threaded portion  127  at the other end. A nut  128  is threaded onto the threaded portion  127  of the mounting bolt  124  and tightened to fix the pivot arm  101 , bushing  115  and adjusting sleeve  119  together while allowing rotation of the bushing  115  within the sleeve bearings  106 ,  107  in the bearing housing  102 . For example, the bolt  124  and nut  128  can be tightened to a torque of approximately 150 ft-lbs. 
     At least one disc spring  129  is positioned on the adjusting sleeve  119 . In the illustrated embodiment, a group of three disc springs  129  are positioned on the adjusting sleeve  119 . A first thrust washer  130  is positioned between the second end  113  of the pivot arm  101  and the bearing housing  102 . A pair of second thrust washers  131  is positioned between the disc springs  129  and the bearing housing  102 . 
     The adjusting sleeve  119  has at least one keyway  132 , and preferably two keyways, on its external surface  123 . A tab washer  133  is positioned on the adjusting sleeve  119  between the second thrust washers  131  and the disc springs  129 . The tab washer  133  has at least one tab  134 , and preferably two tabs, mated with the keyway(s)  132  on the adjusting sleeve  119 . The tab washer  133  minimizes rotative motion and resulting wear between the disc springs  129  and the tab washer  133 . 
     An adjusting nut  135  is threaded onto the threaded external surface  123  of the adjusting sleeve  119 . The adjusting nut  135  preferably comprises a locknut having a nylon insert to prevent the nut  135  from loosening on the adjusting sleeve  119  during operation. The adjusting nut  135  is tightened to compress the disc springs  129  to create a lateral bearing force between the pivot arm  101  and the bearing housing  102 . 
     The mounting bolt  124  has a grease zerk  136  and a lubrication port  137  extending through its shaft for delivering lubricating material into the bearing housing  102 . The lubricating material can be delivered through the mounting bolt  124  to the inner bore  118  of the bushing  115 , and through a corresponding port  138  in the bushing  115  to the inner bore  105  of the bearing housing  102  to lubricate the bearing surfaces between the outer surface of the bushing  115  and the inner bores  108  of the sleeve bearings  106 ,  107 . 
     The following process can be used to remove the OEM closing wheel arm from a drill and install the closing wheel arm pivot assembly of the present invention. 
     The closing wheel arm  101  is removed from the bearing housing  102 , and the old OEM sleeve bearings (not shown) are removed from the bearing housing  102  and may be discarded. 
     New grooved sleeve bearings  106 ,  107  are installed in the bearing housing  102 . The outer ends of the bearings  106 ,  107  should be approximately ¼″ from the ends  103 ,  104  of the bearing housing  102 . If a grease zerk which was previously installed in the bearing housing is to be used, it may be necessary to drill a small hole through the sleeve bearing in line with the tapped hole in the bearing housing. 
     The seals  109 ,  110  are then installed in the ends  103 ,  104  of the bearing housing  102  with the lips of the seals  109 ,  110  facing outward. This arrangement of the seals  109 ,  110  is important to allow grease to be able to pass through the seals  109 ,  110 . The seals  109 ,  110  are pressed into the bearing housing  102  until they are flush with the ends  103 ,  104  of the housing  102 . 
     Grease is applied to the lips of the seals  109 ,  110  and to one end of the pivot bushing  115 . The pivot bushing  115  is installed into the bearing housing  102  through the inner bores of the seals  109 ,  110  and sleeve bearings  106 ,  107  being careful not to damage the seals  109 ,  110 . The thrust washer  130  is installed onto the end  116  of the pivot bushing  115 . 
     The locknut  135  is installed flush with the outer end  120  of the adjusting sleeve  119 . The disc springs  129 , tab washer  133 , and two thrust washers  131  are installed onto the adjusting sleeve  119 . The grease zerk  136  is installed into the mounting bolt  124 . A washer  139  is installed onto the mounting bolt  124 , and the mounting bolt  124  is installed through the bore  125  in the pivot arm  101 , the pivot bushing  115 , the washer  140 , and the adjusting sleeve  119 . 
     The locknut  128  is then installed onto the threaded end  127  of the mounting bolt  124  and tightened to a torque of approximately 150 ft-lbs. The large locknut  135  on the adjusting sleeve  119  is not yet tightened, and the pivot arm  101  should still be loose. The assembly  100  is then lubricated using the grease zerk  136  until grease appears at both ends  103 ,  104  of the bearing housing  102 . 
     The large locknut  135  is then tightened on the adjusting sleeve  119  until there is approximately 1/32 to 1/16 of an inch gap between the two inner disc springs  129 . The lateral looseness should be eliminated. When raising the pivot arm  101  by hand, resistance will be felt caused by the spring pressure of the disk springs  129 , but the pivot arm  101  should not hang up. The large locknut  135  can then be adjusted as necessary. 
     While the invention has been specifically described in connection with specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.