Abstract:
A method and apparatus for soil conditioning, the apparatus comprising a frame, a rotary harrow supported by the frame for engaging the soil and a plurality of disks supported by the frame and in front of the rotary harrow along the advancing direction for rotation about disk axis and for engaging soil below the frame, each disk including a scalloped peripheral edge that forms a plurality of teeth and a space between each two adjacent teeth.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   Not applicable. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   BACKGROUND OF THE INVENTION 
   The present invention is related to seedbed conditioning tillage tools and more specifically to vertical tillage tools. 
   To prepare a seed bed for planting, many types of tilling tools have been developed. Currently, the most commonly used tilling tools include cultivators and combination tillage units that include soil engaging components (i.e., disks, tillage tines, etc.) that completely sweep (i.e., smears) an entire tillage floor to turn over and loosen all of the top soil that covers a field. For example, some tillage systems may include two rows of disks arranged such that the disks essentially completely turn over all top soil in a field. To this end, the disks are designed to have characteristics and are juxtaposed with respect to each other and a travel direction such that all of the soil is turned. Typically, to turn all soil via disks, each disk is relatively deeply concave and is inclined at a relatively steep angle with respect to the travel direction. In addition to loosening top soil, these types of tilling tools also have an advantageous leveling effect on soil as they are pulled through a field. Here, level soil is important to minimize bounce of planter assemblies that are subsequently used in a field so that seed depth can be relatively accurately controlled. Unfortunately, while these types of tilling tools loosen or till top soil well, these types of tools tend to compact under soil (i.e., soil below the top soil) as portions of the soil engaging components smear across the under soil during travel. More specifically, when a deep dish disk is inclined relatively steeply to a travel direction, the backside of the disk tends to smear and compress soil therebelow. When under soil is smeared, the density of the under soil increases and root growth is inhibited. 
   To reduce the smearing effect, rotary spike harrows have been developed that, as the label implies, include rotary spike toothed members that are mounted to a harrow axle and that generally rotate about a horizontal harrow axis substantially normal to or on a slight incline (e.g., 15°-35°) with respect to a travel direction. Here, the spikes of each toothed member penetrate soil by being driven substantially vertically downward and disrupt the soil as the spike angle within the soil changes during member rotation. The end result is tillage with less smearing effect (slight smearing still results in some applications). 
   While rotary spike harrows reduce smearing/soil compaction, unfortunately these types of tilling tools have several shortcomings. First, rotary spike toothed harrows usually include a relatively large number of toothed members arranged on an axle so that the weight of the tilling implement is distributed over a large number of member teeth and the spikes do not, under typical soil conditions, penetrate the soil being tilled to a desired level during a single pass. Second, rotary spike toothed harrows do not level soil to the same extent as other types of tilling tools during a single pass through a field. Here, the shortcomings of the spike toothed harrows can be overcome by increasing the number of passes through a field (e.g., 3 passes instead of a single pass). Obviously additional passes require additional time and thus are not desirable. 
   Thus, it would be advantageous to have a tilling tool or assembly that could adequately till a field in a single pass while minimizing smearing and soil compaction. 
   BRIEF SUMMARY OF THE INVENTION 
   At least some embodiments include an apparatus for soil conditioning for transport through a field in an advancing direction, the apparatus comprising a frame, a rotary harrow supported by the frame for engaging the soil and a plurality of disks supported by the frame and in front of the rotary harrow along the advancing direction for rotation about disk axis and for engaging soil below the frame, each disk including a scalloped peripheral edge that forms a plurality of teeth and a space between each two adjacent teeth. 
   In some cases each tooth includes a leading concave cutting edge and a following convex edge wherein, as each disk rotates, the leading concave edge of each tooth enters the soil prior to an associated following convex edge. In some embodiments each tooth further includes a lateral edge between the leading and following edges. In some cases the spaces divide each pair of adjacent lateral edges and wherein each space has a gap dimension that is approximately twice the size of the lateral edge length. In some cases each disk includes between fourteen and twenty teeth. 
   In some cases each of the disks includes first and second oppositely facing sides and each disk is convex to the first side and concave to the second side. In some embodiments the disk axis are similarly angled with respect to the advancing direction, a frame axis is perpendicular to the advancing direction and the disk axis form a disk angle of between five and twenty degrees with respect to the frame axis with the second sides of the disks opening in the advancing direction. In some cases each of the blade angles is between seven and ten degrees with respect to the frame axis. 
   In some cases the rotary harrow includes spike toothed members mounted for rotation about a harrow axis and wherein the harrow axis is angled at a harrow angle with respect to the frame axis. In some cases the disks are arranges to form grooves in the soil that extend along the advancing direction and the rotary spike harrow is arranged to form diagonal grooves that are angles with respect to the advancing direction and wherein the grooves formed by the harrow form a 15° to 45°angle with the grooves formed by the disk blades. 
   In some cases each disk is concave, has a diameter between 16 and 24 inches, has a depth of between one-half and one and one-half inches and has a radius of curvature of between 600 and 1000 millimeters. In some cases each disk has a diameter of approximately 20 inches, a depth of approximately one-half to one inch and a radius of curvature of approximately 920 millimeters. In some cases each tooth is a radially extending tooth. 
   The invention also includes an apparatus for soil conditioning for transport through a field in an advancing direction, the apparatus comprising a frame, a rotary harrow supported by the frame for engaging the soil and a plurality of disks supported by the frame and in front of the rotary harrow along the direction of travel for rotation about disk axis and for engaging soil below the frame, each disk including a scalloped peripheral edge that forms a plurality of teeth and a space between each two adjacent teeth, each tooth including a leading concave cutting edge, a following convex edge and a lateral edge between the leading and following edges, wherein, as each disk rotates, the leading concave edge of each tooth enters the soil prior to an associated following convex edge, spaces dividing each pair of adjacent lateral edges, each space having a gap dimension that is approximately twice the size of the lateral edge length, each disk including first and second oppositely facing sides and each disk is convex to the first side and concave to the second side, each disk having a diameter between 16 and 24 inches, a depth of between one-half and one and one-half inches and having a radius of curvature of between 600 and 1000 millimeters. 
   In some cases the disk axis are similarly angled with respect to the advancing direction, a frame axis is perpendicular to the advancing direction and the disk axis form a disk angle of between seven and ten degrees with respect to the frame axis with the second sides of the disks opening in the advancing direction. In some embodiments the disks are arranges to form grooves in the soil that extend along the advancing direction and the harrow is arranged to form diagonal grooves that are angles with respect to the advancing direction and wherein the grooves formed by the harrow form at least a 15° to 45° angle with the grooves formed by the disk blades. 
   Some embodiments include a method for soil conditioning, the method comprising the steps of mounting a rotary harrow below a frame for engaging soil below the frame, providing a plurality of disks, each disk including a scalloped peripheral edge that forms a plurality of teeth and a space between each two adjacent teeth, mounting the disks to the frame in front of the rotary harrow along an advancing direction for rotation about disk axis and for engaging soil below the frame and moving the frame, disks and harrow in the advancing direction through a field with the harrow and disks engaging soil there below. 
   In some embodiments the step of providing disks includes providing a plurality of disks wherein each tooth includes a leading concave cutting edge and a following convex edge wherein, as each disk rotates, the leading concave edge of each tooth enters the soil prior to an associated following convex edge. 
   Some embodiments include an apparatus for soil conditioning for transport through a field in an advancing direction, the apparatus comprising a frame having a frame axis that is perpendicular to the advancing direction and a plurality of dished concave disks supported by the frame and in front of the rotary harrow along the advancing direction for rotation about disk axis that are angled between 7 and 10 degrees with respect to the frame axis and for engaging soil below the frame, each disk including a scalloped peripheral edge that forms a plurality of teeth, each disk having a diameter between 16 and 24 inches, a depth of between one-half and one and one-half inches and a radius of curvature of between 600 and 1000 millimeters. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a side perspective view of a tillage assembly according to at least one embodiment of the present invention; 
       FIG. 2  is a top plan view of the tillage assembly of  FIG. 1 ; 
       FIG. 3  is a side view of one of the disks of the tillage assembly of  FIG. 1 ; 
       FIG. 4  is a cross-sectional view of the disk of  FIG. 3 ; 
       FIG. 5  is an enlarged top plan view of a portion of the tillage assembly of  FIG. 1 ; 
       FIG. 6  is a view similar to the view of  FIG. 3 , albeit illustrating a second type of disk that may be used instead of the saw tooth disk in a tillage assembly like the one illustrated in  FIG. 3 ; 
       FIG. 7  is a side perspective view of an exemplary spike toothed harrow that may be employed in some inventive embodiments. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to the drawings wherein like reference numerals correspond to similar elements throughout the several view and, more specifically, referring to  FIG. 1 , the present invention will be described in the context of an exemplary work vehicle  12  having a vehicle support structure to which a plurality of wheels  26  are rotatably mounted. A work vehicle  12  typically has a power source coupled to a transmission with the transmission operatively coupled to at least two of the wheels  26 . The power source can be an internal combustion engine such as a gasoline engine or a diesel engine and it may also be an electric motor or a steam driven turbine. 
   Referring still to  FIG. 1  and also to  FIG. 2 , a tillage assembly  10  is illustrated which is linked to tractor  12  by a tow bar  16 . In addition to tow bar  16 , tillage assembly  10  includes a main frame  14 , wheels, one subassembly of wheels identified by numeral  24 , first through forth disk subassemblies  32   a ,  32   b ,  32   c  and  32   d  and first and second rotary spiked tooth harrows  22   a  and  22   b , respectively. Frame  14  includes a plurality of rigid steel members that are welded or otherwise mechanically secured together to form a rectilinear frame assembly as best seen in  FIG. 2 . A frame axis  15  that is perpendicular to a travel direction  50  is shown twice in  FIG. 5 . While frame axis  15  are parallel to frame members in the  FIG. 5  embodiment, axis  15  need not be parallel to any frame members in other embodiments where frame members are not perpendicular to the travel direction  50 . Tow bar  16  extends forward from frame  14  to mount assembly  14  to tractor  12  as illustrated. Wheels  24  are mounted to and extend down from main frame  14  to support frame  14  above soil in a field through which tillage assembly  10  is pulled by tractor  12 . 
   Referring still to  FIGS. 1 and 2  and also to  FIG. 5 , for the purposes of the present invention, each of the disk subassemblies  32   a ,  32   b ,  32   c  and  32   d  have similar constructions and operate in a similar fashion and therefore, in the interest of simplifying this explanation, only subassembly  32   a  will be described in any detail. Subassembly  32   a  includes, among other components, an implement mounting bar  18 , a plurality of disks, two of which are collectively identified by numeral  30  in each of  FIGS. 2 and 5 , and some type of adjusting mechanism (e.g., a hydraulic cylinder  60 , turn buckle, etc.). 
   In at least one embodiment, as illustrated best in  FIGS. 3 and 4 , each of the disk members  30  include a concave disk that forms outwardly extending teeth  40   a ,  40   b , etc., on its circumferential edge. Each of the teeth  40   a  and  40   b  are identical and therefore, in the interest of simplifying this explanation, only tooth  40   a  will be described here in detail. As shown, tooth  40   a  is a saw blade type tooth and, to that end, includes a concave leading edge  44 , a convex following edge  48  and a lateral edge  46  that extends from the leading edge  44  to the following edge  48 , the lateral edge  46  and following edge  48  forming a tooth point (not labeled). Each two adjacent teeth  40   a ,  40   b , etc., are separated by a gap or space (e.g.,  42 ). Each disk  30  forms one or more generally centrally located mounting openings  38 . Referring specifically to  FIG. 4 , each disk  30  has first and second oppositely facing surfaces  31  and  33 , respectively. Surface  31  is convex while surface  33  is concave where each of the surfaces  31  and  33  has a similar radius of curvature R. Exemplary disk  30  has a diameter dimension D i  and a depth dimension D e  as illustrated. 
   As mentioned above, each tooth ( 40   a ,  40   b , etc.) includes a concave leading edge  44 , a convex following edge  48  and a lateral edge  46  that extends from the leading edge  44  to the following edge  48 . As shown particularly in  FIG. 3 , each of the teeth further include a rearward pitch, or slant,  94  angled toward the following convex edge  48 . Rearward pitch  94  is the slant of the tooth as measured by the angle between 1) a radial extension  96  through disk center point  98  and the center  100  of the base of a corresponding tooth, and 2) the centerline  102  of the tooth. 
   Referring to  FIGS. 3 ,  4  and  5 , disks  30  are mounted to implement mounting bar  18  such that the disks are aligned for rotation about a common disk axis  19  that is generally parallel to the length of bar  18 . Thus, each disk is mounted so as to be generally perpendicular to bar  18 . 
   Referring to  FIGS. 1 and 5 , bar  18  mounts below frame  14  such that disks  30  extend downward below main frame assembly  14  and engage soil therebelow. In this regard, a first end  51  of bar  18  is pivotally mounted to frame  14  and a second end  53  of bar  18  is journalled in a slot forming member  55  to slide therealong as bar  18  pivots about first end  51 . Adjusting mechanism  60  includes a first end mounted to frame  14  and a second end mounted to a central portion of bar  18 . 
   When bar  18  is mounted to frame  14 , bar  18  is juxtaposed so that bar  18  and disk axis  19  form an angle α with respect to frame axis  15 . When bar  18  is angled, disks  30  are inclined at a similar angle α with respect to travel direction  50 . When so inclined, the second surfaces  33  (see again  FIG. 4 ) of disks  30  generally open in the direction of travel  50 . To adjust angle α between bar  18  and frame axis  15 , cylinder  60  is manipulated. When cylinder  60  is extended, angle α is increased and, when cylinder  60  is retracted, angle α is decreased. 
   Referring again to  FIG. 5 , as assembly  10  is moved through a field, disks  30  engage soil therebelow and form grooves, two of which are collectively identified by numeral  69 . As described in greater detail below, disks  30  are selected such that their dimensions and characteristics and their spacing along bar  18  result in grooves  52  that are separated by loosened/disturbed soil bands (e.g.,  71 ) therebetween. 
   Referring again to  FIGS. 2 and 5 , in most applications, disk subassemblies  32   a  and  32   b  will be mounted to frame assembly  14  such that the component mounting bar members (e.g.,  18 ) form similar angles a with respect to the frame axis  15 . Similarly, each of disk subassemblies  32   c  and  32   d  are mounted to frame assembly  14  so as to form angles a, albeit where the angles formed by subassemblies  32   c  and  32   d  with respect to frame axis  15  are in the opposite direction (e.g., where angle α of subassembly  32   a  is −7°, angle α of subassembly  32   c  and  32   d  will be approximately +7°). 
   Referring to  FIG. 2 , harrows  22   a  and  22   b  are similar and operate in a similar fashion and therefore, in the interest of simplifying this explanation, only harrow  22   a  will be described here in detail. Referring also to  FIGS. 1 and 5 , harrow  22   a  is a rotary spike toothed harrow that is mounted below frame assembly  14  and behind disk subassemblies  30  along the travel or advancing direction  50 . Referring to  FIG. 7 , an exemplary perspective view of harrow  22   a  is shown where it can be seen that harrow  22   a  includes multiple spike toothed members  90  arranged to rotate along a common harrow axis  17 . Harrow  22   a  has a length dimension along axis  17 . Harrow  22   a  can be adjusted with respect to frame axis  15  such that an angle β between harrow axis  17  and frame axis  15  can be modified. To this end, a second adjusting mechanism  62  (e.g., hydraulic cylinder, turn buckle, etc.) is provided between frame assembly  14  and harrow  22   a . Construction and operation of spike toothed rotary harrows is well known in the art and therefore are not described here in detail. Here, it should suffice to say that in operation, as harrow  22   a  is pulled through a field, the spike toothed members  90  engage soil therebelow and form generally lateral grooves, three of which are collectively identified by numerals  70  in  FIG. 5 . Here, the lateral grooves  70  form angles β with respect to the travel direction  50  that are similar to the angle β formed between harrow axis  17  and main frame axis  15 . 
   Referring to  FIGS. 1 through 5 , in at least some embodiments, disks  30  are selected to have specific characteristics and are mounted so as to engage soil therebelow in a vary specific manner that minimizes the smearing effect caused by other types of disks. To this end, in a particularly advantageous embodiment, it has been found that smearing can be reduced by selecting disks  30  that have relatively minimal depth D e  dimensions and that are scalloped or toothed in some fashion and by mounting the disks to rotate about a disk axis (e.g.,  19 ) that is only slightly angled from the frame axis  15 . Here, the idea is to use the disks to initially disturb the soil to a point where a single spike toothed harrow pass will cause adequate tillage to occur while minimizing soil smearing. In effect, the disks work the soil to a generally optimal point for the harrows to work ideally while causing minimal smearing. In this regard, referring to  FIG. 5 , because the disks  30  have a narrow depth D e  and angle α is minimal (e.g., 7-10°), as the disks  30  rotate, the disks form grooves  69  with loosened bands  71  of soil therebetween. In addition, because the disks have narrow depths and are minimally inclined with respect to travel direction  50 , the disks cause reduced backside disk blade pressure which has several advantages. First, reduced or substantially eliminated backside pressure means that smearing and compaction of the soil is minimized or substantially eliminated. Second, reduced backside pressure means that the forces working against disk penetration are minimized and therefore the weight of frame  14  can be advantageously reduced as a light frame  14  can cause sufficient penetration. 
   In at least one advantageous embodiment, disks  30  are selected that have diameters D i  that are approximately 20 inches, that have depths D e  that are approximately one-half to one and one-half inch and that have radiuses of curvature R of approximately 920 mm and the disks are mounted below frame  14  such that the inclined angle α of the disks with respect to the travel direction  50  is between 7 and 10 degrees. 
   Referring again to  FIG. 3 , in a particularly advantageous embodiment, saw tooth type disks  30  are employed where the dimension of the portion of each gap  42  between lateral edges (e.g., see  46  in  FIG. 3 ) of adjacent teeth  40   a  and  40   b  is approximately twice the dimension of each of the lateral edges  46 . Thus, for example, where the dimension of the portion of gap  42  between adjacent lateral edges is 2.6 inches, each of the adjacent lateral edges would have a length of approximately 1.3 inches. In the illustrated embodiment disk  30  has 16 teeth. In other cases the number of teeth may vary. Here, the idea behind toothed disks is to relocate soil while minimizing the actual engagement of the disk with the soil. In the present example, 66% of the soil engaging portion of the disk is removed yet the rippled or scalloped grooves  69  (i.e., continuous grooves with depth variations therealong) in the soil are essentially continuous because soil that is engaged pushes against adjacent soil and causes the adjacent soil to breakout and loosen. 
   Referring again to  FIG. 3 , in advantageous embodiments disks  30  are juxtaposed with respect to travel direction  50  such that, as the disks engage field soil and rotate, leading tooth edges  44  are driven toward the soil followed by associated following edges  48  on common teeth (e.g.,  40   a ). Here, edges  46  tend to cut through field debris well and penetrate the soil effectively while only causing minimal soil compaction when compared to non-scalloped or non-toothed type disks or saw tooth type disks where the concave edges lead the convex edges. 
   After the disks  30  loosen the soil and form grooves  69 , rotary harrows  22   a ,  22   b , operate at angles (e.g., 45° or more with respect to travel direction  50 ) to dislodge undisturbed or loosened soil between the grooves  69 , to level loose soil and evenly distribute residue in the soil. 
   While the dimensions and disk axis angle range described above are believed to be particularly advantageous, it is believed that other similar dimensions and similar axis angles will cause similar effects. For instance, it is believed that the blade depth D e  may, in some cases, may be in the one-half to one and one-half inch range, the diameter D i  may be between 16 and 24 inches and the radius of curvature R may be between 600 and 1000 millimeters. The angle α may be between 5° and 20° depending upon disk depth and diameter dimensions. Here, the important aspect is that the combination of disk characteristics (e.g., depth, diameter, radius of curvature) and disk juxtaposition (e.g., incident angle α with respect to the travel direction) be selected to reduce or minimize smearing of soil below the assembly  10 . In the present case, while the disk assemblies (e.g.,  32   a ) form grooves and only loosen much of the top soil, the resulting soil is suitable for a single pass of a harrow to result in effective tillage for most applications. 
   While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. For example, referring to  FIG. 6 , a notched disk  80  is illustrated that could be substituted for the saw tooth disks of  FIG. 3  to achieve a similar result. Disk  80  includes  18  radially extending teeth  82   a ,  82   b , etc., that are separated by semi-circular recesses or gaps  84 . Here, disk  80  is concave and would be arranged in a fashion similar to that illustrated in  FIG. 5  with the concave side opening in the travel direction  50 . Once again the depth D e  of disk  80  would be minimized and the inclination angle α would be minimal to reduce backside pressure and hence to reduce soil smearing. 
   Thus, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims. To apprise the public of the scope of this invention, the following claims are made: