Abstract:
A ground opener unit for a seeding or planting unit includes an accessory mount attachable to an implement frame and a disc rotatably mounted to the accessory mount for forming a furrow in the ground. A scraper assembly includes a scraper plate defining a scraper edge for contacting and scraping a surface of the disc. The scraper plate is mounted to the arm by a pivot pin whose length defines a pivot axis about which the scraper plate may pivot in response to deflection of the disc. A spring is generally held in compression to bias the scraper plate against the disc.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to ground opener units, such as planting units for forming a furrow in the ground and depositing seeds therein. More particularly, the present invention relates to equipment of the type noted above employing a spring biased scraper devices for cleaning a surface of the disc opener used therein. 
     Planting assemblies of the type noted above are typically arranged such that the opener disc is held at an angle from the forward direction of travel so that the disc has a leading face and a trailing face. The disc displaces soil laterally as it travels forward and opens a furrow following the trailing face. In wet conditions, soil tends to stick to the trailing face so it is common to provide a scraper to clean the disc. The scraper also acts to prevent loose soil from falling back into the furrow until the seed is properly placed into the furrow. The disc is subject to flexing as lateral forces are applied to the disc when opening the furrow. The scraper must be held close to the disc but not so tightly as to cause a braking action on the disc; therefore it is desirable for the scraper to be allowed to flex and move with the disc&#39;s deflection. 
     The prior art has provided a variety of scraping devices for use in angled disc openers. Reference may be had for example to U.S. Pat. Nos. 4,760,806 and 5,787,994. Another exemplary scraping device employed a bracket which supported the disc scraper and which included a three bolt triangular pattern for adjusting the angle of the bracket. The bracket pivoted on the head of a carriage bolt as the three fasteners were tightened to effect angle adjustment. However, this prior design had a number of disadvantages in that adjustment of one fastener required corresponding readjustment of at least one of the other fasteners; adjustment of the desired angle was complicated and time consuming with the three fastener system and the bracket often became permanently deformed if one fastener was tightened without first loosening the others. Additionally, this rigid adjustment system did not allow the scraper to flex in response to irregularities or flexing of the disc blade. 
     Another exemplary scraping device is disclosed in U.S. Pat. No. 6,237,696, which describes the use of a resilient pad held against the scraper plate. The resilient pad provides enough force to hold the scraper plate against the disc so as to prevent debris, e.g., soil, from passing between the scraper plate and the surface of the disc, but is made of material that compresses to allow the scraper plate to deflect with deflection of the disc. The resilient pad has a limited range of travel and lacks a well defined point or axis of rotation. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a disc scraper assembly that permit quick and ready adjustment of the scraper to provide a scraper mounting that may pivot to allow scraper flexing in response to disc irregularities or flexing of the disc during use and furthermore to provide for rocking motion of the scraper about a well defined pivot axis thereby to assist in keeping the scraper edge against the disc surface while the disc flexes during use, thereby to ensure proper cleaning at all times. 
     A scraper assembly for a disc opener in accordance with the invention in one aspect includes a scraper plate defining a scraper edge for contacting and scraping a disc. The scraper plate defines a mounting region remote from the edge. The assembly further includes a scraper plate mount adjacent the mounting region and a spaced pair of fasteners extending through the mounting region to secure the scraper plate to the scraper plate mount. A biasing assembly couples the scraper plate mount to the frame of the disc opener. The biasing assembly includes a pin for coupling the scraper plate mount to the frame in a manner that allows limited pivoting of the scraper plate relative to a long axis of the pin and further includes a biasing component for placing a biasing force on the scraper plate such that the scraper plate maintains contact with the disc during deflection of the disc. 
     The above-noted biasing component preferably comprises a spring that is held in compression, which holds the scraper plate against the disc surface. When the disc flexes, the spring force applied by the biasing component allows the scraper plate to likewise flex so that a relatively consistent engagement of the scraper plate against the disc surface is maintained. 
     According to another embodiment of the invention, the scraper edge is disposed such that disc surface irregularities encountered by the scraper edge tend to create moments of force and pivoting motion of the scraper plate about a pivot axis defined along the length of the pivot pin. 
     In a further aspect of the invention the above described scraper assembly is combined with a ground opener unit including an accessory mount attachable to an implement frame and having a disc rotatably mounted to the accessory mount for forming a furrow in the ground. The disc is preferably held, in use, at an angle to the forward direction of travel to displace soil and open a furrow so that the disc has a leading surface and a trailing surface with the scraper assembly being adapted to scrape the trailing surface of the disc. 
     It is an advantage of this invention that the depth adjustment is relatively simple. 
     It is another advantage of this invention that the pivot pin provides a well defined axis of rotation of the scraper plate. 
     It is still another advantage of this invention that the biasing component provides bias of the scraper plate toward the disc surface while allowing flexing in response to disc deflection. 
     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; 
         FIG. 2  is side elevation view of a disc ground opener unit incorporating a disc scraper assembly for use with the agricultural system of  FIG. 1  in accordance with an embodiment of the invention; 
         FIG. 3  is a rear end elevation view of the disc ground opener unit of  FIG. 2 ; 
         FIG. 4  is a partial exploded view of the disc ground opener unit of  FIG. 2 ; and 
         FIG. 5  is an isometric view of the seed tube and scraper plate of the disc ground opener unit of  FIG. 2 . 
     
    
    
     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  FIGS. 2 and 3 . Each disc opener unit  20  includes a linkage assembly  24  that in the illustrated unit includes a pair of links  26 ,  28  that are coupled to the tool bar  18  in a known manner at one end and connected to an accessory mount  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. That is, the gauge wheel  34  has a resilient shallow tire extending around its perimeter having a lip  34 ( a ) which engages the adjacent face of the opener disc  22  to clean the latter during rotation in known fashion. A scraper blade  36  on the opposite side of the disc  22  is provided 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 or boot assembly  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 packer wheel  40  packs the furrow after the seed and/or fertilizer has been deposited. More particularly, the trailing wheel  40  is pivotally connected to the accessory mount  30  by way of a rearwardly extended packer arm  42  and a coil tension spring  44  that is connected between the packer arm  42  and accessory mount  30 . The tension spring  44  biases the packer wheel  40  toward the ground to help close the furrow opened by disc  22  after seeds have been implanted therein in known fashion. 
     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 on handle  48 . The accessory mount  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 (not shown) that carries the gauge wheel  34  and the disc  22 . 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 . 
     Referring now to  FIGS. 4-5 , the seed boot assembly  38  includes a seed tube  54  having an inlet end  56  flow-coupled to the air cart and an outlet end  58  through which seed is passed onto to the planting surface. The seed tube  54  is preferably integrally formed with a scraper mount  60  that includes a pair of mounting brackets  62  and  64 . The mounting brackets  62 ,  64  respectively include upwardly extending legs  66 ,  68  adjacent opposite sides of the seed tube  54  and mounting flanges  70 ,  72  flared outwardly from the legs  66 ,  68 . In a preferred embodiment, the mounting brackets  62 ,  64  are integrally formed with the seed tube  54 . The flanges  70 ,  72  each include a set of scraper plate mount holes  74  and  76  that allow adjustability in the mounting of the scraper blade  36  to the scraper mount  60 . The scraper plate  36  includes holes  78 ,  80  that are spaced from one another so to align with the respective sets of scraper plate mount holes  74 ,  76 . With the scraper holes  78 ,  80  aligned with selected ones of the scraper plate mount holes  74 ,  76 , fasteners  82  are inserted into the aligned holes and secured to the in place in a known manner, e.g., nuts  84 . In a preferred embodiment, the scraper plate  36  can be mounted at three different positions or heights relative to the disc  22 . Alternately, two sets of mounting holes could be formed in the scraper plate  36  with single holes formed in the mounting brackets  62 ,  64 . It is also contemplated that each set of mounting holes could take the form of a slot effectively defining an infinite number of mounting positions. It is also contemplated that the scraper plate could be shimmed to provide additional adjustability. This adjustability allows the placement of the scraper plate to be adjusted in response to changing characteristics of the disc  22 . For example, as the disc  22  wears down, the scraper plate  36  may need to be raised to account for the smaller diameter of the disc  22 . Conversely, if the scraper blade becomes worn and a new disc is mounted, it may be desirable to lower the height of the scraper blade  36 . It will be appreciated that the spacing between and the number of spacer mount holes  74 ,  76  may be different from that illustrated in the figures. The upper ends  66 ,  68  each include an eyelet  86 ,  88 , the function of which will be described more fully below. 
     The frame  30  includes an accessory bracket  90  to which the seed boot assembly  38  is mounted. More particularly, the accessory bracket  90  includes a lower end  90 ( a ) and an upper end  90 ( b ), which is coupled to link  28  in a known manner. Arms  92 ,  94  extend upwardly from the lower end  90 ( a ). Each arm  92 ,  94  has a respective eyelet  96 ,  98 , and the arms  92 ,  94  are aligned such that eyelets  96 ,  98  are coaxial. The arms  92 ,  94  are spaced so that the legs  66 ,  68  of the seed boot assembly  38  are received in the space between the arms  92 ,  94 . When properly positioned, the eyelets  86 ,  88 ,  92 , and  94  will all co-align so that a pin  100  can be passed through the eyelets. The pin  100  can then be secured through the eyelets by a fastener  102 , e.g., a cotter pin. Since the diameter of the pin  100  is less than the diameter of the eyelets and since the pin  100  is loosely retained by cotter pin  102 , the seed boot assembly  38  is free to pivot about the pivot pin  100 . 
     The leading edge of the scraper plate  36  is biased against the trailing surface of the disc  22  by a spring  104 . With additional reference to  FIG. 5 , the spring  104  is held in a pocket  106  of a planar member  108  formed between the legs  66 ,  68  on the backside of the seed boot assembly  38 . A spacer  110  compresses the spring  104  in the pocket  106 . A retainer plate  112  is fastened to the lower end  90 ( a ) of the bracket  90  by a lock ring  114  and fastener  116 . The retainer plate  112  has a width sufficient to press against the backend of the spacer  110  to hold the spacer  110  against the spring  104 , as shown in  FIG. 2 . In an alternate embodiment, a pocket is formed in the lower end  90 ( a ) of the bracket. In this alternate embodiment, the spring  104  would therefore have one end seated in the pocket  106  of the seed boot assembly  38  and the other end seated in the pocket of the bracket  90 . This embodiment would not use spacer  110  or retainer plate  116 . Additionally, other types of biasing devices, such as a rubber plug, could be used instead of spring  104 . 
     As noted above, the spring  104  biases the scraper plate  36  into engagement with the disc  22 . The mounting of the seed boot assembly  38 , and thus the scraper plate  36 , to the bracket  90  by a pivotable connection allows the scraper plate  36  to deflect with deflection of the disc  22 , such as when the disc hits an obstruction. Thus, when the disc  22  is pushed outwardly the spring will push the scraper plate  36  outwardly to maintain engagement with the disc  22 . In a preferred embodiment, the spring  104  can be further compressed to allow the scraper plate to move inwardly in response to an inward movement of the disc. It will thus be appreciated that the present invention advantageously maintains contact of the scraper plate with the disc as the disc flexes in response to varying forces on its surfaces as it operates in the soil. Additionally, the invention maintains contact of the scraper plate with the disc despite distortions in the surface of the disc, which may occur during fabrication of the disc, for example. 
     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.