Patent Abstract:
A zeroing adjustment for a depth control system of an agricultural seed planting implement has an adjustable link to compensate for the variable effects of tolerance stack-up and wear, so that all planting units of the implement can be adjusted to a common zero ground penetration setting from which depth settings can be made.

Full Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to agricultural seed planting implements and to the depth-setting mechanism on furrow opening assemblies of such implements, and more particularly to an assembly for adjusting the depth-setting mechanism. 
     2. Description of the Related Art 
     Farmers utilize a wide variety of seed planting implements, including seed drills and planters. In a known type of planting implement, seed planting or row units are attached to a toolbar extending transverse to the direction of planting. The toolbar is coupled to a tractor or other work vehicle suitable for pulling the planting implement along a field that is to be seeded to a crop. Each planting unit includes a ground penetrating assembly, often including one or more discs, for opening a seed trench or furrow in the ground as the planting implement is pulled across a field. Components of the ground penetrating assembly shape the bottom and sides of the seed trench, and a seed metering device provides individual seeds at a controlled rate for deposit in the seed trench. Furrow closing components of each row unit close the seed trench in a controlled manner. 
     It is a desirable and perhaps even primary agronomic principle that seeds should be planted at precisely controlled and consistent depths both within a row and from row to row. Since a single planting implement may be used to plant several different types of crops and/or the same crop in different planting locations under different planting and growing conditions, it is necessary that the planting depth is adjustable so that the seeds are placed at a depth that has been determined to be the best for seed germination and plant growth of the particular crop under the existing and anticipated conditions. 
     To control planting depth, it is known to provide gauge wheels that travel on the surface of the field to control the depth to which the ground penetrating assembly can run, the positions of the gauge wheels being adjustable so that the depth of the seed trench can be controlled within fractions of an inch. Adjustment linkages are provided for changing the relative positioning of the gauge wheels with respect to the ground penetrating assembly. It is known to move the adjustment linkage by a handle connected thereto, the handle engaging a register having multiple positions for securing the handle to maintain the position to which the handle is adjusted. 
     As growers have gained greater understanding about seed germination and plant growth, and as soil preparation procedures have changed and improved, crop growers have demanded more precise control over seed placement both in the spacing between seeds and in the depth at which the seeds are placed below the soil surface. Accordingly, there is both a demand and a need for even more precise control over the depth of the seed trench that is formed during planting operations. While depth-setting mechanisms have been designed for ever more precise settings, the linkages and other structures forming the depth setting mechanisms have multiple components and connections which can lead to setting errors due to the variable effects of tolerance stack-up, wear and the like. In planting implements having multiple seed planting or row units, it is necessary that all units be similarly calibrated so that all units plant to the same planting depths when set to the same settings. The multiple components and linkages present in depth-setting mechanisms can acquire unacceptably large variations from one row unit to another in the accumulated stack of tolerances in the component parts even when new, and after wear has occurred and/or if parts have been replaced, planting depths can vary significantly between row units that have been adjusted to the same planting depth settings. 
     What is needed in the art is a structure for zeroing the depth setting mechanisms in a seed planting implement to adjust out the varying effects of tolerance stack-up and wear between different seed planting units of the implement. 
     SUMMARY OF THE INVENTION 
     The present invention provides a seed planting implement with consistent depth setting control for ground penetrating components of the implement by providing an adjustable link in the adjustment mechanism to compensate for the variable effects of tolerance stack-up and wear. 
     In one form thereof, the invention is directed to an agricultural seed planting implement with a ground penetrating assembly, a depth setting linkage assembly including a control assembly and a depth control linkage arm associated with the ground penetrating assembly and having adjustable positions for changing a depth to which the ground penetrating assembly can operate. The depth control linkage arm is selectively variable in length. 
     In another form, the invention is an agricultural seed planting implement with a toolbar and a plurality of individual seed planting units connected to the toolbar. Each seed planting unit of the plurality of seed planting units includes a ground penetrating assembly and a depth control assembly for changing a depth to which the ground penetrating assembly can operate. Each depth control assembly is adjustable to a common setting from which depth settings are made for the ground penetrating assemblies. 
     In a further form thereof, the invention is an agricultural seed planting implement with a ground penetrating assembly, an adjustable gauge wheel supporting said ground penetrating assembly at controlled penetration depths; and a depth control linkage arm adjustably positioning said gauge wheel, said depth control linkage arm having a selectively variable length. 
     An advantage of the zeroing adjustment for depth control systems disclosed herein is that the penetration depth for seed planting equipment can be more accurately and consistently set across multiple planting units of an agricultural seed planting implement. 
     Another advantage of the zeroing adjustment for depth control systems disclosed herein is that it compensates for the variable effects of tolerance stack-up and wear. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of an agricultural seed planting implement; 
         FIG. 2  is a perspective view of one of the seed planting units of the seed planting implement; 
         FIG. 3  is a side view of the seed planting unit; 
         FIG. 4  is another perspective view of the seed planting unit, showing the unit from an angle different from the angle shown in the perspective view of  FIG. 2 ; 
         FIG. 5  is a fragmentary side view of the seed planting unit illustrating inner components used for depth setting; 
         FIG. 6  is a perspective view a depth setting linkage assembly in the seed planting unit; 
         FIG. 7  is a side view of the depth linkage assembly; 
         FIG. 8  is a fragmentary elevation view of the seed planting unit; 
         FIG. 9  is a cross-sectional view of the seed planting unit; and 
         FIG. 10  is another perspective view of the linkage assembly as installed and adjusted. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one embodiment of the invention and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings more specifically and to  FIG. 1  in particular, a seed planting implement  10  is shown. Seed planting implement  10  has a frame that includes a tow bar assembly  12  having a tow bar  14  and a connection assembly  16  at the longitudinally forward end thereof configured for mating with a corresponding hitch of a tractor or other work vehicle (not shown) for pulling seed planting implement  10  through a field. A laterally extending toolbar  18  is generally transverse to tow bar  14  and thereby generally transverse to the direction implement  10  is towed during planting operations. A plurality of seed planting units (or row units)  20  are connected to toolbar  18  in a side by side relationship, each of the seed planting units (row units) being substantially identical to the others. In the exemplary embodiment shown, seed planting implement  10  includes sixteen seed planting units  20 , only some of which are identified with reference numbers; however, it should be understood that more or fewer seed planting units can be provided on a particular seed planting implement. 
     Referring now primarily to  FIG. 2  through  FIG. 5 , each seed planting unit  20  includes a frame  22  that is connected to toolbar  18  by upper arms  24  and lower arms  26 , each arm  24 ,  26  being connected to frame  22  and to toolbar  18 . Accordingly, each seed planting unit  20  extends rearward from toolbar  18  to plant a row of seeds as seed planting implement  10  is towed across a field. The individual planting units  20  are spaced along toolbar  18  to provide planted seed rows of a desired spacing. During a planting operation, forward movement of seed planting implement  10  causes each seed planting unit  20  to form a seed trench, deposit equally spaced seeds in the seed trench and close the seed trench over the seeds deposited in the seed trench. 
     Each seed planting unit  20  includes a ground penetrating or seed trench opening assembly  30  ( FIG. 3 ) having a pair of forwardly and downwardly angled opening discs  32  that converge forwardly and downwardly to open a furrow or seed trench as seed planting implement  10  moves forward. A seed metering system  34  receives seeds from a seed hopper  36  and provides individual seeds at a controlled rate to a seed tube  38  for deposit in the bottom of the seed trench formed. A vacuum system  40  ( FIG. 1 ), which includes a fan  42  and air lines  44 , provides vacuum to seed metering system  34  for the operation of the seed metering system in supplying seeds to seed tube  38 . 
     A seed trench closing mechanism  50  ( FIG. 1 ) at the trailing end of each seed planting unit  20  closes the seed trench after the seeds have been deposited in the seed trench. Seed trench closing mechanism  50  includes a pair of closing wheels  52  ( FIG. 2 ) that operate on opposite sides of the seed trench to move soil back into the seed trench and over the seeds deposited in the bottom of the seed trench. A trailing press wheel  54  ( FIG. 1 ) travels along the top of the seed trench and firms the soil replaced in the seed trench to eliminate air pockets. 
     The depth to which opening discs  32  are allowed to penetrate the ground is controlled by a depth control assembly  60  ( FIG. 5 ) that includes a pair of gauge wheels  62 , gauge wheel arms  64  and a depth setting and linkage assembly  80 . One of the gauge wheels  62  is provided adjacent each opening disc  32 . Each gauge wheel  62  is rotatably mounted on one of the gauge wheel arms  64  that are pivotally connected at a pivotal attachment  66  to seed planting unit frame  22 . Each gauge wheel arm  64  has a wheel retention segment  68  extending generally rearward from pivotal attachment  66  and a control segment  70  extending generally upward from pivotal attachment  66 . Pivotal movement of gauge wheel arm  64  about pivotal attachment  66  to frame  22  changes the relative height position of gauge wheel  62 . 
     A pivoted position to which each gauge wheel arm  64  is placed is controlled by depth setting and linkage assembly  80  having a depth setting control assembly  82 , a depth control linkage arm  84  and a wobble bracket  86  connected to linkage arm  84  by a pivotal connection  88 . Control assembly  82  adjusts an axial position for linkage arm  84  and thereby the position of wobble bracket  86 , with wobble bracket  86  engaging control segments  70  of gauge wheel arms  64 . Raising gauge wheels  62  allows opening discs  32  to penetrate deeper into the ground, and lowering gauge wheels  62  limits the depth to which discs  32  can penetrate into the ground. 
     Referring now primarily to  FIG. 4  through  FIG. 6 , control assembly  82  includes a pivot arm  90  of general V-shape, with a pivotal connection  92  at the base thereof to seed planting unit frame  22 . An inner arm  94  of pivot arm  90  has a pivotal connection  96  to depth control linkage arm  84 . An outer arm  98  of pivot arm  90  extends through a depth setting register  100 . Depth setting register  100  defines a slot  102  with a first row of notches  104  along one side of slot  102  and a second row of notches  106  along an opposite side of slot  102 . Opposed pairs of notches including one of the notches  104  and one of the notches  106  define securing locations for securing the position of pivot arm  90  after adjustment thereof. 
     A handle  108  is provided on the distal end of outer arm  98  and includes laterally projecting position holding pegs  110 ,  112  for engaging notches  104 ,  106  of register  100 . The pairs of notches including one of the notches  104  and one of the notches  106  secure the position of pivot arm  90  by receiving and engaging pegs  110 ,  112 . Handle  108  is mounted on a spring  114 , and can be depressed relative to outer arm  98  such that pegs  110 ,  112  disengage notches  104 ,  106  by sliding inwardly through the notches so that handle  108  can be moved fore and aft in slot  102  to align pegs  110 ,  112  with different pairs of notches  104 ,  106 . As handle  108  rebounds outwardly, pegs  110 ,  112  slide into the pair of notches  104 ,  106  with which the pegs are aligned. Movement of handle  108  fore and aft pivots pivot arm  90  about its pivotal connection  92 , and thereby extends or withdraws depth control linkage arm  84 , to alter the position of wobble bracket  86 , which in turn controls the positions of control segments  70  and thereby the allowable height of gauge wheels  62 . 
     Depth control linkage arm  84  includes a rearward portion  130  that is connected to pivot arm  90  by pivotal connection  96 , and a forward portion  132  that is connected to wobble bracket  86  by pivotal connection  88 . An intra-link connection  134  between rearward portion  130  and forward portion  132  is axially adjustably so that the overall length of linkage arm  84  is selectively variable. Rearward portion  130  and forward portion  132  are telescopically engaged with one another to accommodate the overall axial adjustability of connection  134  to change the overall length of linkage arm  84 . 
     Referring now more particularly to  FIG. 7 , connection  134  includes a bolt  136  extending through one or more fixed block  138 ,  140  fixed between side plates  142 ,  144  of forward portion  132  and received by threaded engagement in a threaded block  146  affixed to rearward portion  130 . Bolt  136  includes a shank  150  that is threaded along at least a portion of an end thereof, and a head  152  having a drive configuration  154  ( FIGS. 9 &amp; 10 ) formed therein for engagement by an appropriate tool for rotating bolt  136 . In the exemplary embodiment shown, drive configuration  154  is a hexagonal depression for receiving a hex key (Allen wrench) in rotational drive engagement. It should be understood that drive configuration  154  can be of other shaped depressions in head  152  to engage other internally received drive tools, or drive configuration  154  can be an external shape of head  152  to receive a wrench, drive socket or the like. Head  152  includes opposed external flats  156 ,  158  ( FIG. 10 ) that also can receive a wrench, drive socket or the like. Advancing the threaded engagement of bolt  136  into threaded block  146  decreases the overall length of depth control linkage arm  84 , and retracting the threaded engagement of bolt  136  from threaded block  146  increases the overall length of depth control linkage arm  84 . 
     Referring now particularly to  FIG. 10 , a lock mechanism in the form of a bracket or cage  160  is provided to secure the position to which bolt  138  has been adjusted. Cage  160  has sides  162 ,  164  and an end  166 . End  166  has a shaped hole  168  therein including opposed flats  170 ,  172  to receive and engage head  152 , with flats  156 ,  158  of head  152  received against flats  170 ,  172  of shaped hole  168  to prevent further rotation of bolt  138 . Sides  162 ,  164  of cage  160  are received against side plates  142 ,  144 , and together side plates  142 ,  144  and sides  162 ,  164  form aligned holes  174 ,  176  for receiving a pin forming pivotal connection  88 . It should be understood that other structures can be used for preventing the unintended rotation of bolt  136  after the adjustment thereof. 
     Zero adjustment or calibration of depth control assembly  60  is performed upon initial assembly and can be performed again from time to time as a maintenance procedure. For example, it may be desirable to zero adjust the system after significant wear and/or when replacement parts have been installed. Zero adjustment is performed with wobble bracket  86 , pivotal connection  88  and cage  160  not yet installed (during initial assembly) or removed (when performed as a maintenance step). Seed planting implement  10  is adjusted so that toolbar  18  is elevated, lifting all seed planting units  20  off the ground. As illustrated in  FIG. 8 , each gauge wheel  62  drops, pivoting its respective gauge wheel arm  64  about the pivotal attachment  66  thereof until adjustable control segment  70  contacts a frame stop  178 . This allows removal of wobble bracket  86 , pivotal connection  88  and cage  160  when performed as a maintenance operation or the insertion of depth control linkage arm  84  during assembly. 
     With seed planting implement  10  thus prepared, toolbar  18  is lowered until opening discs  32  barely contact a flat level surface upon which implement  10  is positioned. Opening discs  32  thereby rest at a zero penetration setting, and depth control assembly  60  can be adjusted for proper registration of handle  108  at the zero penetration setting. Control assembly  82  is adjusted such that handle  108  is engaged with the appropriate notches  104 ,  106  for a zero penetration setting. Bolt  136  is then adjusted relative to threaded block  146  to advance further into or to withdraw further from threaded block  146 , while at all times remaining threadedly engaged there with. In this way, the overall length of depth control linkage arm  84  is adjusted so that when wobble bracket  86  is re-attached thereto it will properly engage control segments  70  of gauge wheel arms  64  and without unacceptable looseness. It should be understood that the appropriate length for control linkage arm  84  can be determined in numerous ways, including measurement between the end thereof and a fixed point such as, for example, depth setting register  100  or another fixed point of reference. A convenient way for determining the proper overall length of linkage arm  84  is by the use of a gauge  180 . As illustrated in  FIG. 9 , gauge  180  includes wings  182 ,  184  to be received in wobble bracket slots  186  of control segments  70 . Bolt  136  is rotated so as to advance further into, or withdraw further from threaded block  146  and thereby change the overall length of depth control linkage arm  84  until the outer end of control linkage arm  84  is received at a designated position relative to gauge  180  and wings  182 ,  184  are properly received in wobble bracket slots  186 . Bolt head  152  is adjusted as necessary so that flats  156 ,  158  thereof are properly positioned such that cage  160  can be installed with shaped hole  168  thereof engaging bolt head  152 , with flats  156 ,  158  of bolt head  152  disposed against flats  170 ,  172  in shaped hole  168  of cage  160 . Gauge  180  is removed, and cage  160  is installed. Wobble bracket  86  and pivotal connection  88  are installed, thereby securing cage  160  in position and locking bolt  136  against unintended rotation. 
     When all row units  20  of seed planting implement  10  are adjusted in this manner to a common zero penetration setting, each will have a common elevation relative to the zero setting to which it was adjusted. Each can then be set so that the opening discs  32  thereof will penetrate a same depth into the ground if the control assemblies  82  thereof are adjusted to similar settings in registers  100 . In that way, all row units that are set to the same settings will deposit seeds at the same depths below the surface of the ground. 
     While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Technology Classification (CPC): 0