Abstract:
An adjustment mechanism for setting the position of a singulator in a seed meter. The singulator comprises an arm pivotally mounted about a pivot adjacent a seed disk. A shaft with an eccentric connection to a radially outward portion of the arm has a lever pivotally connected on it. The lever has a cam mechanism to displace an actuating sleeve into a resilient sleeve to lock the shaft in a given position when the lever is extending in the direction of the axis of rotation of the shaft. When the lever is moved to a right angle orientation the shaft is free to pivot and thus set the position of the arm.

Description:
FIELD OF THE INVENTION 
   The present invention relates to agricultural seeding machines, and, more particularly, to seed metering systems used to meter seeds for placement in a seed trench. 
   BACKGROUND OF THE INVENTION 
   An agricultural seeding machine such as a row crop planter or grain drill places seeds at a desired depth within a plurality of parallel seed trenches formed in soil. In the case of a row crop planter, a plurality of row crop units are typically ground driven using wheels, shafts, sprockets, transfer cases, chains and the like. Each row crop unit has a frame which is moveably coupled with a tool bar. The frame may carry a main seed hopper, herbicide hopper and insecticide hopper. If a granular herbicide and insecticide are used, the metering mechanisms associated with dispensing the granular product into the seed trench are relatively simple. On the other hand, the mechanisms necessary to properly meter the seeds, dispense the seeds at a predetermined rate and place the seeds at predetermined relative locations within the seed trench are relatively complicated. 
   The mechanisms associated with metering and placing the seeds generally can be divided into a seed metering system and a seed placement system which are in communication with each other. The seed metering system receives the seeds in a bulk manner from the seed hopper carried by the frame. Different types of seed metering systems may be used such as seed plates, finger plates, and seed disks. In the case of a seed disk metering system, a seed disk is formed with a plurality of seed cells spaced about the periphery thereof. Seeds are moved into the seed cells, with one or more seeds in each seed cell depending upon the size and configuration of the seed cell. A vacuum or positive pressure air may be used in conjunction with the seed disk to assist in movement of the seeds into the seed cells. The seeds are singulated and discharged at a predetermined rate to the seed placement system. 
   The seed placement system may be categorized as a gravity drop system or a power drop system. In the case of a gravity drop system, a seed tube has an inlet end which is positioned below the seed metering system. The singulated seeds from the seed metering system merely drop into the seed tube and fall via gravitational force from a discharge end thereof into the seed trench. The seed tube may be curved in a rearward manner to assist in directing seed into the seed trench. The rearward curvature also assists in reducing bouncing of the seeds back and forth within the tube as it falls into the seed trench. Further, the rearward curvature reduces bouncing of the seed as it strikes the bottom of the seed trench. 
   A seed placement system of the power drop variety generally can be classified as a seed conveyor belt drop, rotary valve drop, chain drop or air drop. These types of seed placement systems provide more consistent placement of the seeds along a predetermined path at a desired spacing. 
   Certain seed types, notably flat corn seed with insecticide or other treatments, are difficult for vacuum meters to singulate. Poor singulation of difficult seed types is characterized by doubles, skips, and bunches of seed carried by the disk. Doubles and skips refer to multiple seeds and no seed respectively in each seed cell. Bunches are multiple seeds carried up by the seed pool accelerators which protrude from the surface of the seed disk. These seed types generally are best planted with a flat seed disk in combination with double eliminator. Compared to a celled disk, a flat disk has less favorable seed trajectory into the seed tube, generally requires more vacuum, and a production “double eliminator” adjustment is difficult. 
   What is needed in the art is an agricultural seeding machine having an accurate positive and efficient adjustment of a double eliminator or singulator mechanism. 
   SUMMARY OF THE INVENTION 
   The invention includes an apparatus for setting the position of an arm pivotally mounted about a pivot for knocking off extra seeds from a seed metering disk. The apparatus has an arm mounted for pivotal movement and a shaft having an eccentric connection to a location on the arm radially spaced from the pivot point so that rotational displacement of the shaft causes the arm to pivot about the pivot point. A lever is pivotally mounted to the shaft about an axis approximately at a right angle to the longitudinal axis of the shaft. An element contacts the shaft and is connected to the lever, the lever being pivotal between first and second positions, the first permitting rotational displacement of the shaft and the second position preventing rotational displacement. 
   In another form, the invention includes a seeding machine having at least one seed metering system, each seed metering system including a housing and a seed disk disposed within the housing, the seed disk having a rotational axis and a plurality of seed cells defining a generally circular path. An arm is pivotally mounted on the housing about an axis generally parallel to the rotational axis of the seed dish and is positioned adjacent the seed cells. The shaft is journaled about an axis generally parallel to the rotational axis of the seed disk, the shaft having an eccentric connection to the arm at a location spaced from the pivotal axis of the arm. A lever is pivotally mounted to the shaft about an axis approximately at a right angle to the longitudinal axis of the shaft. An element contacts the shaft and is connected to the lever. The lever is pivoted between first and second positions, the first permitting rotational displacement of said shaft by said element and the second position preventing rotational displacement of said shaft by said element. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a seed metering unit incorporating a singulator adjustment device embodying the present invention; 
       FIG. 2  is a perspective view of the singulator adjustment shown in  FIG. 2 ; 
       FIG. 3  is an exploded perspective view of the singulator adjustment device of  FIGS. 1 and 2 ; 
       FIG. 4  is a highly expanded fragmentary view of a portion of the singulator device of  FIGS. 1-3 ; 
       FIG. 5  is a fragmentary exploded view of the singulator of  FIGS. 1-5 ; and 
       FIG. 6  is a graph showing displacement of the singulator device of  FIGS. 1-5  as a function of the rotation of an adjustment handle. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , a seed meter, generally indicated by reference character  10 , is incorporated in a seeding machine (not shown). The seeding machine has many additional features such as a main hopper or seed air pump to deliver seed to individual seed meters of which unit  10  is one of multiple units. Details of such an overall system may be found in U.S. Pat. No. 6,758,153, of common assignment with this invention, the disclosure of which is hereby incorporated in its entirety. The seed meter  10  includes a housing  12  and a seed hopper  14  which receives an appropriate supply of seeds from a main hopper (not shown). Seed hopper  14  delivers seeds to a chamber in a housing  16  at the lower portion of housing  12 . A seed disk  18  is journaled in housing  12  and has a seed side  22  exposed to chamber  16  and a lower pressure side  24  exposed to a vacuum source for maintaining a pressure differential across seed disk  18 . Seed disk  18  has a plurality of seed cells  20  positioned in a circular fashion around seed disk  18 . Seed cells  20  may take many different forms, but in the illustrated form they are apertures extending through seed disk  18  to connect the seed side  22  to the lower pressure side  24 . It should be understood by those skilled in the art that the pressure levels of sides  22  and  24  may be reversed. 
   Seed disk  18  is journaled on shaft  26  which is driven by an appropriate motor  28  through a gear mechanism (not shown) to turn the seed disk  18  in the direction of arrows A. The seeds that have accumulated against the bottom of seed disk  18  then find their way to the seed cells by virtue of the pressure differential across the seed disk. As the disk turns in a counterclockwise fashion, as shown in  FIG. 1 , the seeds that are in the seed cells are retained one at a time. The rotation of the disk takes the individual seeds to a segment (not shown) where the pressure differential is locally interrupted so that the seed may be discharged into an appropriate planting mechanism. 
   Because of the variability of the shape and size of seeds, double seeds may be retained within the seed cells. To eliminate this condition, a singulator, generally indicated by reference character  30 , is provided. Although this component may be referred to as a singulator it is also described in the art as a “double eliminator”. The singulator  30  includes an arm  32  pivotally mounted to housing at screw  34  and positioned adjacent the path of the seed cells  20 . The arm  32  has a plurality of ramps  36  and  38  to knock off double seeds that have been somehow retained or lodged in the seed cells  20 . Arm  32  is generally arcuate in shape and has an adjustment mechanism, generally indicated by reference character  40 , at an end radially spaced from pivot screw  34 . The purpose of mechanism  40  is to cause the singulator  30  to pivot about pivot screw  34  and accommodate seeds of different varieties and grades to provide the most effective elimination of double seeds. The adjustment mechanism  40  is operator manipulated in accordance with the present invention. 
   As shown in  FIGS. 2-4 , the adjustment mechanism  40  includes a central shaft  42  journaled in a bore  44  in housing  12 . Shaft  42  has an integral flange  46  with an eccentric pin  48  received in a slot  50  in arm  32 . Consequently, rotational displacement of shaft  42  causes the pin  48  to move within slot  50  and cause arm  32  to pivot about its pivot screw  34 . Shaft  42  receives a sleeve  54  that abuts flange  46  at end  56 . The outer diameter of sleeve  54  also abuts the interior diameter of bore  44 . Sleeve  54  is elastomeric so that it may be deformed. An annular ridge  52  on shaft  42  deforms the sleeve  54  slightly so that some drag is placed on the mechanism during the adjustment process. The opposite end  58  of sleeve  54  abuts an actuating sleeve  60 , also received on shaft  42 . 
   As noted especially in  FIGS. 3 , shaft  42  has flats  62  extending longitudinally. The flats  62  on shaft  42  match flats  64  on the interior wall of sleeve  60  so that sleeve  60  is non-rotatable relative to shaft  62 , although sleeve  60  can move axially. A lever  66  is pivotally mounted on shaft  42  by means of a pin  68  passing through a hole  70  in shaft  42 . Pin  68  is approximately at right angles to the flat  62  which in turn is parallel to the axis of rotation of shaft  42 . Lever  66  has a pair of base elements  72  and  74  which are received on opposite sides of shaft  42  adjacent hole  70 . Base elements  72  and  74  have aligned holes  76  and  78  which receive and fix pin  68  in appropriate fashion. As especially evident in  FIG. 3 , the flats  62  and  64  are asymmetric with respect to the rotational axis of shaft  42 . In turn, the base elements  72  and  74  have different thicknesses. This prevents incorrect assembly of the adjustment mechanism  40 . 
   When the singulator  30  is assembled as shown in  FIG. 2 , the resilient sleeve  54  abuts flange  46 , actuating sleeve  60  abuts resilient sleeve  54 , and lever  66  is positioned on shaft  42  so that base elements  72  and  74  abut the end  80  of actuating sleeve  60 . Base elements  72  and  74  have cam surfaces  82  contoured to have a distance from pin  68  that is at a minimum when lever  66  is approximately at a right angle to the axis of rotation of shaft  42 . The cam surfaces  82  increases from that point so that as lever  66  is moved in a counterclockwise fashion as shown in  FIG. 2 , cam surfaces  82  push actuating sleeve  60  towards the resilient sleeve  54 , in turn compressing it against flange  46  and expanding it within bore  44 . The resultant expansion of sleeve  54  prevents and resists any rotation of shaft  42 . When lever  66  is approximately 90° from the position shown in  FIG. 2 , flats  84  on cam surfaces  82  cause a detent when the lever  66  is in its locked position where it is extended axially. 
   As shown particularly in  FIG. 4 , the actuating sleeve  60  has a plurality of molded indicia  86  to indicate the relative rotational displacement of actuating sleeve  60 , and therefore shaft  42 , relative to a corresponding molded indicia  88  on housing  12 . Thus, an operator is able to determine visually the position of the singulator  30  relative to the seed disk  18 . 
     FIGS. 2-4  show another feature in the form of a detent  47  on flange  46  which receives a metal strap  49  appropriately fixed to housing  12  (not shown in  FIGS. 2 and 3 ). Metal strap  49  is formed to urge a projection  51  into detent  47 , when the shaft  42  and actuating sleeve  60  are positioned to have the middle indicia  86  line up with the indicia  88  on housing  12 , as shown in  FIG. 4 . In other positions, the projection  51  rides on the periphery of flange  46 . This enables an operator to feel when the adjustment is in a pre-selected position, in this case the midpoint of the range of adjustments. 
   As shown in  FIG. 5 , the slot  50  in arm  32  has a recess  90  extending around the ends of slot  50  so that any debris trapped within slot  50  will be more easily purged. Furthermore the slot  50 , instead of having a straight linear shape relative to the longitudinal dimension of arm  32 , has a predetermined, non-linear shape. The shape is in the form of a curve preselected so that the displacement of pin  48  and therefore arm  32  in the direction of the arrows B and C is approximately linear when the arm  32  is being adjusted around a common adjustment point. This is shown in  FIG. 6  wherein the distance from the center of the seed disk  18  is shown on the Y axis and the rotation of the shaft  42  in degrees is shown on the X axis. A straight slot configuration is shown as curve D and the movement of the element with slot  50  is shown as curve E. It can be seen that the movement is approximately linear which gives an operator a better feel for the movement of the singulator  30 . Furthermore, as shown in  FIG. 6 , the movement within the range of the seed cell location for a seed corn disk has a lower rise than for a straight slot. Consequently, operator adjustment is becomes finer and more precise. 
   To adjust the singulator  30 , the lever  66  is pivoted to a radial position and it is moved either clockwise or counterclockwise to pivot the shaft  42  to the appropriate location. It should be noted that the lever  66  gives greater leverage than previous serrated knobs used to manipulate the handle. Furthermore, the adjustment mechanism  40  permits an infinite range of rotational positions when compared to the previous step-wise adjustment of prior art designs. In addition, the indicia  86  molded into the actuating sleeve  60  gives a permanent indication of the position of the shaft regardless of dirt accumulation or long term wear. 
   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.