Abstract:
A packing pressure adjustment assembly for a ground opener unit of an agricultural implement includes a spring interconnected between a rotatable pressure adjustment arm and a trailing arm to which a packer wheel is rotatably mounted. The pressure adjustment arm is centered about an axle of the ground opener unit and is movable between a set of mounting positions that are defined by a set of teeth spaced and arced from one another along a frame portion of the ground opener unit. As the pressure adjustment arm is rotated, the amount of force exerted by the spring on the trailing arm is varied. The packing pressure adjustment assembly is relatively compact and is useful in providing high packing forces, such as a packing force in excess of 100 lbs.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to ground opener units for an agricultural implement and, more particularly, to an assembly for adjusting the packing pressure applied by a trailing packer wheel of a disc opener unit. 
     One type of planting implement is commonly equipped with one or more rows of discs or coulters carried by a tool bar, commonly referred to as a disc drill, which is towed by a tractor. Typically, an air cart, which holds seed and/or fertilizer, is also towed by the tractor and pneumatically supplies the individual disc openers with seed and/or fertilizer. The disc openers are attached to the disc drill frame by individualized arms or linkages which allow the disc openers to operate independently of another. This “independence” allows the discs to independently respond to changes in terrain and field obstructions. 
     Each disc has a generally flat construction that is rotated a few degrees, e.g., 7 degrees, about a vertical axis so that as the disc is pulled through the soil the leading surface of the disc displaces soil and creates a furrow in the soil. Downward pressure on the disc is provided by a spring or hydraulic cylinder to hold the disc at a desired furrowing depth, e.g., desired seeding depth. The depth at which the disc cuts the furrow into the soil is controlled by a gauge wheel that runs in relative close proximity to the disc. In addition to its depth controlling function, for some disc drills, the placement of the gauge wheel close to the disc also assists in keeping the disc surface clean of soil, mud, or debris buildup. Also, the gauge wheel rides over the soil displaced by the disc as the furrow is being cut to prevent the displaced soil from being thrown. 
     The disc cuts a furrow or trench in the soil into which seed and/or fertilizer is deposited. The seed and/or fertilizer is dropped through a tube into the trench, and the disc holds the trench open on one side and a disc scraper blade holds it open on the opposite side. The trench walls then collapse onto the seed and/or fertilizer when the disc and scraper blade pass. A trailing wheel then packs the soil atop the seed and/or fertilizer. 
     Most disc drills include a torsion spring that is used to bias the trailing (packer) wheel against the field or planting surface. While generally effective in holding the packer wheel down against the planting surface, such torsion springs are generally unable to create high packing forces, such as those greater than 100 lbs. Additionally, for many disc drills, the placement of the torsion spring is such that the spring is prone to collect field trash and other debris. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a packer wheel assembly overcoming the aforementioned drawbacks. The invention provides a compact packer wheel pressure adjustment assembly having an adjustment arm that can be rotated to one of multiple positions to change the amount of packing pressure exerted by the packer wheel. The adjustment arm interfaces with a biasing member, such as a spring, that adjusts the amount of packer wheel pressure as a function of the position of the adjustment arm. The multiple positions at which the adjustment arm can be engaged correspond to a range of desirable packer wheel pressures, including a position that results in excess of 100 lbs of packer wheel pressure. 
     It is therefore an object of the invention to provide a compactly designed packer wheel pressure adjustment assembly. 
     The invention also advantageously provides a biasing spring capable of providing packing pressures in excess of 100 lbs. 
     Other objects, features, aspects, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout. 
       In the drawings: 
         FIG. 1  is a pictorial view of an agricultural system generally comprised of tractor, an air cart, and a disc drill having a set of disc openers; 
         FIG. 2  is a side elevation view of a disc opener unit of the disc drill of  FIG. 1 ; 
         FIG. 3  is an enlarged isometric view of a portion of the disc opener unit of  FIG. 2 ; 
         FIG. 4  is a exploded view of the disc opener unit of  FIG. 2 ; 
         FIG. 5  is a section view of the disc opener unit taken along line  5 - 5  of  FIG. 2 ; 
         FIG. 6  is an enlarged section view of the disc opener unit taken along line  6 - 6  of  FIG. 5 ; and 
         FIG. 7  is an isometric view of the spindle of the disc hub assembly of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and more particularly to  FIG. 1 , an agricultural planting system  10  is shown and, as known in the art, is generally comprised of a tractor  12 , an air cart  14 , and a planter  16 . The air cart  14  and the planter  16  are hitched to the tractor  12  in a conventional manner. The planter  16  includes a tool bar  18  to which a set of disc opener units  20  are coupled. The disc opener units  20  each include a disc  22  designed to cut a furrow into the soil. As known in the art, the air cart  14  pneumatically delivers seed and/or fertilizer to a set of delivery tubes (not shown) of the planter  14  whereupon the seed and/or fertilizer is deposited in seed trenches or furrows cut by the discs  22 . 
     An exemplary disc opener unit  20  is shown in  FIG. 2 . Each disc opener unit  20  includes a linkage assembly  24  that in the illustrated unit includes links  26 ,  28  that are coupled to the tool bar  18  in a known manner at one end and connected to an opener frame  30  at the opposite end. The opener unit  20  includes a spring  32  that applies downward pressure on the disc  22 . Alternately, a hydraulic cylinder may be used to apply such downward pressure. Disc penetration is controlled by a gauge wheel  34  that is positioned in relative close proximity to the disc  22 . In addition to controlling the penetration depth of the disc  22  the gauge wheel  34  also helps in keeping the adjacent side of the disc  22  clear of debris. A scraper blade  36  is provided on the opposite side of the disc  22  to keep the leading face of the disc  22  clear of soil, mud, and debris. In one preferred embodiment, the disc  22  is angled at an offset of approximately 7 degrees from vertical; although, different orientations are contemplated. The leading side of the disc  22  displaces soil and creates a furrow in the soil as the disc  22  is pulled through the soil by the tractor  12 . In addition to providing a scraping function the scraper blade  36  also helps to hold the furrow open as seed and/or fertilizer is deposited into the furrow. 
     The disc opener unit  20  also carries a seed tube  38  that is flow-coupled to the air cart  14 . As known in the art, seed and/or fertilizer is provided to the seed tube  38  which drops the seed and/or fertilizer into the furrow. A trailing wheel  40 , coupled to the frame  30  by arm  42 , packs the furrow after the seed and/or fertilizer has been deposited. The amount of packing pressure applied by the trailing wheel  40  is controlled by a packing pressure adjustment assembly  44 , which will be described in further detail below. 
     As noted above, the gauge wheel  34  controls the penetration depth of the disc  22 . The gauge wheel  34  may be raised or lowered by rotation of a depth adjustment arm  46 . Arm  46 , which includes a generally T-shaped handle  48 , may be rotated by a user pulling upward on handle  48 . As shown in  FIG. 3 , the frame  30  includes an arc of notches  50  that define a range of discrete engagement points at which the handle  48  may be positioned. In one preferred embodiment, the notches  50  allow the gauge wheel  34  to set the penetration depth between 3.2 mm and 87 mm. The handle  48  has teeth  52  that are received by a selected number of the notches  50  to position the handle  48 , and thus the arm  46 , at a desired position. The arm  46  is coupled to a spindle  54  that as described below also carries the gauge wheel  34  and the disc  22 . As such, rotation of the arm  46  between the discrete positions varies the position of the gauge wheel  34  and thus the penetration depth of the disc  22 . 
     To better illustrate the design of the disc opener unit  20  reference is now made to  FIG. 4 , which provides an exploded view of a portion of the disc opener unit  20 . The frame  30  includes a generally cylindrical sleeve  56  into which spindle  54  is received. With additional reference to  FIG. 8 , the spindle has a body  58  defined between a first end  60  and a second end  62 . The disc  22  is mounted to a hub  64  using nuts  66  and bolts  68  in a conventional manner. The hub  64  has a bearing  70  pressed into it with a pair of washers  72 ,  74  and a snap ring  76  operative as a retainer. While different types of bearings are contemplated, bearing  70  preferably has a split inner race. Each inner half is placed from each side and clamped together. When clamped, a correct internal clearance is provided. The hub  64 , bearing  70 , washers  72 ,  74 , and snap ring  76  collectively define a hub assembly  78  that is slid onto end  60  of the spindle  54 . As best shown in  FIG. 6 , the spindle  54  has a shoulder  80  that provides a defined stop for the hub assembly  78 . In this regard, the hub assembly  78  is slid onto the spindle  54  until the inner race of the bearing abuts the shoulder  80 . 
     As described above, the disc  22  is fastened to the hub  64 . It is understood that the disc  22  could be mounted to the hub before or after the hub assembly is placed onto the spindle  54 . With the disc  22  secured to the hub  64  and the hub assembly  68  placed over the first end  60  of the spindle  54 , a gauge arm  82  may be secured to the first end  60  of the spindle  54 . More particularly, the gauge arm  82  has a first end  84  that is passed through central opening  22 ( a ) of the disc  22  and the hub assembly  78  into engagement with the first end  60  of the spindle  54 . In one preferred embodiment, the first end  60  of the spindle  54  and the first end  84  of the gauge arm  82  have complimentary shapes, e.g., square, to facilitate a quick and correct coupling. A bolt  86  and washer  88  are then used to secure the gauge arm  82  to the spindle  54 . 
     The second end  90  of the gauge arm  82  is coupled to a gauge wheel spindle  92  to which the gauge wheel  34  is mounted using bolt  94 . The gauge wheel  34  is mounted to the gauge wheel spindle  92  in a manner that allows the gauge wheel  34  to rotate around the gauge wheel spindle  92 . Preferably, after the disc  22 , hub assembly  78  and gauge wheel  34  have been secured to the spindle  54 , the second end  62  is passed through a v-ring seal  96  and sleeve  56  of frame  30 . The second end  62  of the spindle  54  extends past the sleeve  56  and passes through an opening  98  formed in a lower end  46 ( a ) of the depth adjustment arm  46 . A collar  100  together with a bolt  102  are used to secure the depth adjustment arm  46  to the spindle  54  and secure the spindle  54  to the frame  30 . 
     As further shown in  FIG. 4 , the depth adjustment arm  46  includes an upper end  104  having a pocket  106  for a compression spring  108 . The upper end  104  is secured to the depth adjustment handle  48  by a roll pin  110 . The compression spring  108  functions to keep the teeth  52  of the handle  48  engaged with selected notches  50 . In this regard, a user must pull on the handle  48  sufficiently to overcome the compressive force of the spring  108  to disengage the teeth  52  from the notches  48  and rotate the arm  46  to a new position along the arc of notches  50 . Once the pulling force is removed, the compressive force of the spring  108  draws the handle  48  toward the spindle  54  (axis of rotation for the disc  22 ) and engages the teeth  52  with the notches  50 . 
       FIG. 5  provides a section view of the disc opener unit  20  taken along line  5 - 5  of  FIG. 2 . As illustrated, the spindle  54  defines an axis of rotation for the disc  22  as well as the gauge wheel arm  82  and the depth adjustment arm  46 . As further illustrated in  FIG. 5 , the gauge wheel spindle  92  is offset from spindle  54  but rotates with spindle  54 . In this regard, the spindle  54  acts as a crankshaft for the gauge wheel arm  82  such that as the gauge wheel arm  82  is rotated the gauge wheel  34  is rotated albeit along an axis offset but parallel to the axis of rotation for the spindle  54 . 
     As noted above and with additional reference to  FIG. 6 , a v-ring seal  96  is provided that is used to create a grease pocket, illustrated at reference numeral  112 , between the face of the bearing  70  and the frame  30 . The grease zerk is located on the outside of the frame  30  and is needed for rotation of the spindle  54  when a depth adjustment is made. Referring again to  FIG. 7 , a grease channel  114  is formed along the body  58  of the spindle  54 . The grease channel  114  is formed generally parallel to the long axis of the spindle body  58 . An annular grease grove  116  is formed in the elongated body  58  between the grease channel  114  and end  62  of the spindle  54 . As further illustrated in  FIG. 7 , the grease channel  114  communicates with a cutout  118  formed in the shoulder  80  and is positioned between the shoulder  80  and end  62  of the spindle  54 . 
     As noted above, the present invention also provides a packing pressure adjustment assembly  44 . As will be made apparent from the foregoing description, the packing pressure adjustment assembly  44  has a compact design, is capable of providing high packing pressures, e.g., 100 lbs, and is less prone to debris, mud, and field trash collection than conventional assemblies commonly used to adjust the amount of packing pressure provided by the packer wheel  40 . With reference again to  FIGS. 2-4 , the pressure adjustment assembly  44  is comprised of a spring  120  that is interconnected between an adjustment arm  122  and the trailing arm  42 . The adjustment arm  122  has a lower portion  124  and an upper portion  126 . As shown in  FIG. 4 , the lower portion  124  has an opening  128  though which the end  62  of the spindle  54  is passed. In this regard, the lower portion  124  of the adjustment arm  122  is secured to the spindle  54  by collar  100  and fastener  102 . 
     The upper portion  126  of the adjustment arm  122  has a handle member  130  that has a generally L-shaped body. A groove  132  is formed in the upper portion  126  of the adjustment arm  122  and is designed to receive a first end  120 ( a ) of the spring  120 . In a preferred embodiment, the first end  120 ( a ) of the spring  120  is a downwardly facing hook that is dropped into the groove  132  and held in the groove  132  by the tension in the spring  120 . The adjustment arm  122  is movable between a set of defined positions that are defined by engagement members  134 ,  136 , and  138  formed on the opener frame  30 . The engagement members  134 - 136  are radially spaced from one another so as to have an arc shaped arrangement. The radius of the arc is centered about the axis of rotation of the spindle  54 . Each engagement member  134 - 136  is L-shaped and includes axially extending portion and a forwardly extending portion. The shape of the engagement members  134 - 136  results in a respective gap being formed between the forwardly extending members and the side of the opener frame  30 . The handle member  130  is designed to be secured to the engagement members by seating the handle member  130  against a gap-side surface of the axially extending portions of the engagement members  134 - 136 . The gaps are each sized so that the handle portion is snuggly received and held therein. 
     The opposite end  120 ( b ) of the spring  120  is secured to a forward end  42 ( a ) of the trailing packer wheel arm  42 . More particularly, a hole  140  is formed in the forward end  42 ( a ) of the arm  42  and the end  120 ( b ) of the spring  120  has a upwardly facing hook that is passed through the hole  140 . Tension in the spring  120  retains the hook end  120 ( b ) in the hole  140 . 
     Referring again to  FIG. 3 , a stop bar  142  extends laterally from the frame  30 . The trailing packer arm  42  includes an engagement surface  144  that abuts against the stop  142 . The amount of packing force applied by the packer wheel  40  is adjusted by changing the position of the adjustment arm  122 . When the arm  122  is rotated in a forward direction (counter clockwise direction in  FIG. 3 ), the spring  120  is elongated. This elongation of the spring  120  causes the spring  120  to pull up on the leading end  42 ( a ) of arm  42 . This movement causes the arm  42  to rotate in a rearward direction (clockwise direction in  FIG. 3 ) about pin  146 , which couples the packer arm  42  to the opener frame  30 . As a result, the engagement surface  142  is brought into greater engagement with the stop bar  142 . Stated another way, the increased tension in the spring  120  created as the spring  120  is elongated results in a greater holding force of the trailing arm  42  against the stop bar  142 , which increases the amount of packing force applied by the packer wheel  40 . 
     Conversely, when the adjustment arm  122  is rotated rearwardly (clockwise in  FIG. 3 ), the amount of tension in spring  120  is lessened thereby reducing the force used to hold the trailing arm  42  against stop bar  142 . As such, less packing pressure is applied by the wheel  40 . In a preferred embodiment, the adjustment arm  122  can be positioned at three different positions (defined by engagement members  134 ,  136 ,  138 ), but it is contemplated that more or less positions could be defined. 
     It will therefore be appreciated that the present invention provides a compact packer wheel pressure adjustment assembly having an adjustment arm that can be rotated to one of multiple positions to change the amount of packing pressure exerted by the packer wheel. A spring is provided; although, other types of biasing devices could be used, such as a cylinder, that adjusts the amount of packer wheel force as a function of the position of the adjustment arm. The multiple positions at which the adjustment arm can be engaged correspond to a range of desirable packer wheel pressures, including a position that results in excess of 100 lbs of packer wheel force. 
     Many changes and modifications could be made to the invention without departing from the spirit thereof. The scope of these changes will become apparent from the appended claims.