Abstract:
An in-line sub-surface seeding, fertilizing and watering system includes a blade ( 10 ) mountable into a header member ( 112 ) of a parallelogram linkage ( 110 ). A pair of parallel rigid drag arms ( 116, 118 ) extend between the header member ( 112 ) and a hanger member ( 114 ) and are pinned at their respective ends so that rotation of the header member relative to the hanger member on the parallel arms maintains a general horizontal orientation of the header member thereby supporting the blade ( 10 ) downwardly in a constant orientation. The hanger member is mountable to a supporting frame ( 182 ). A selective actuator such as a hydraulic actuator ( 138 ) or selectively controllable spring assembly ( 147 ) allows selective control of a downward force urging the blade into the soil. Where the selective actuator is a hydraulic actuator ( 138 ) mounted between the hanger member ( 114 ) or frame and the parallel arms ( 116, 118 ) or header member ( 112 ), the actuating linkage may be selectively elevated so as to remove the blade ( 10 ) from the soil.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority from U.S. Provisional Patent application No. 60/132,734 filed May 6, 1999 entitled In-Line Sub-Surface Seeding, Fertilizing and Watering System. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to the field of no-tillage opening blades which may be partially submerged into earth, for example in a farmers field, so as to pass the blade at a submerged depth for delivery of seeds, fertilizer or water into the earth, and to the mechanical system for actuating same. 
     BACKGROUND OF THE INVENTION 
     This invention relates to blade delivery systems which have replaced tillage plows and the like. It is known that the use of plows or other devices having for example tillage discs for tilling the earth or otherwise opening and turning a furrow through the ground suffer from the disadvantage that the moisture in the soil is unnecessarily exposed to evaporation. In the past it was necessary to open the earth so that the ground beneath the surface could be seeded, fertilized and watered. Whether this was accomplished by machinery or done manually, prior art machines or manual systems also suffered from the disadvantage that fertilizer was typically delivered into close proximity to the seeds being sown occasionally resulting in the seeds becoming chemically burnt. 
     Thus there exists a need for, and it is an object of the present invention to provide, a blade and actuating system wherein the blade may be partially submerged into earth and translated therethrough, where the blade disturbs the earth minimally and without tillage and is adapted to deliver one or all of seeds, fertilizer or water from the blade in advantageous spaced apart relation as hereinafter described. 
     SUMMARY OF THE INVENTION 
     The sub-surface seeding fertilizing and watering system of the present invention includes a mechanical actuating linkage for actuating an opening blade. The blade has first and second sides extending between a leading edge and an aft edge. The first and second sides are advantageously generally symmetrical to each other on either side of a first plane, where the first plane generally bisects the opening blade, and the leading edge and the aft edge lie generally in the first plane. 
     The opening blade has an upper surface and a lower surface extending between upper and lower edges respectively of the first and second sides of the blade. First and second wings are mounted to the first and second sides respectively in generally oppositely disposed relation so as to be cantilevered outwardly therefrom. The first and second wings extend between first and second forward wing edges and first and second aft-opening wing apertures in the first and second wings respectively. The first and second wings are mounted to the first and second sides at, respectively, first and second distances from the lower surface measured generally parallel to the first plane. 
     The opening blade has therethrough, and generally lying in the first plane, first and second conduits, extending from, and cooperating with, at uppermost ends thereof, first and second infeed ports in the upper surface. The first and second conduits cooperate with, at lowermost ends thereof, first and second wing ducts extending aft through the first and second wings respectively between the lowermost ends of the first and second conduits and the first and second aft opening wing apertures. The first and second conduits and the corresponding first and second wing ducts are thereby in material flow communication between the first and second infeed ports and the corresponding first and second aft opening wing apertures for seed, fertilizer or fluid flow, as fed from a material feeder, therethrough during the forward translation of the blade. 
     The opening blade is mountable to the material feeder so as to be generally vertically disposed, when mounted thereon for partial submerging into soil to a first submerged depth advancing the leading edge through the soil. The first and second distances are less than the first submerged depth so that the first and second wings are submerged in the soil during the forward translation of the blade. 
     In one preferred embodiment, the opening blade further includes a third conduit extending in material flow communication between a third infeed port in the upper surface and an aft opening blade aperture in a rearward position on the opening blade in proximity to the aft edge for seed, fertilizer or fluid flow therethrough, as fed from the material feeder. Advantageously the aft-opening blade aperture is centrally disposed relative to the first plane so as to lie generally symmetrically across the first plane, and may be positioned so that the aperture intersects the lower surface of the blade. Thus the aft-opening blade aperture is formed at the intersection of the lower surface and the aft edge of the blade. The aft-opening blade aperture may lie in a second plane at generally 30° inclined relative to a third plane generally containing the lower surface of the blade, wherein the third plane is generally orthogonal to the first plane. 
     Advantageously, the first, second and third conduits are generally parallel and raked aft of their corresponding first, second and third infeed ports. The first, second and third conduits may be raked aft at an angle of approximately 55° relative to a fourth plane generally containing the upper surface of the blade if the upper surface is a planar generally horizontal surface, although this is not necessarily so. 
     In one embodiment, but not so as to be limiting, at least the first and second conduits are formed by mating of corresponding opposed facing channels in oppositely mounted side panels, oppositely mounted in, or mountable into, first and second sides of the blade. 
     In a further aspect of the design, the third conduit is generally parallel and adjacent the aft edge and the leading edge is concavely curved and forms a pointed toe at the intersection of the leading edge and the lower surface of the blade. Advantageously, the pointed toe may be made of hardened material relative to the hardness of material forming the balance of the opening blade. 
     In a further aspect, the opening blade may be defined as having a longitudinal length dimension and a height dimension, where the longitudinal length dimension is perpendicular to the height dimension and both dimensions lie in the first plane. Further, the opening blade has a lateral width dimension perpendicular to the first plane. 
     The longitudinal length dimension extends between the leading and aft edges of the blade, the height dimension extends between the upper and lower surfaces of the blade, and the lateral width dimension extends between the first and second sides of the blade. In the present design, the length dimension is much, that is, significantly greater than the width dimension, as described hereinafter. The height dimension in one embodiment is greater than the submerged depth so that the blade is supported above the soil and the blade thus partially submerged during forward translation, although this is not intended to be limiting. That is, it is readily conceivable to mount the blade to a support that itself becomes partially submerged in the soil. 
     Further advantageously, the first and second wings are wedge-shaped and the forward wing edges are vertices of the wedge-shaped wings. 
     The sides of the blade may be thought of as having upper and lower portions respectively above and below the wings. Thus, the first and second sides have upper portions generally located, respectively, between the first and second wings and the upper surface of the blade, and lower portions generally located between, respectively, the first and second wings and the lower surface of the blade. The lower portions collectively form a waisted shape so that a forward width dimension of a forward flared portion of the lower portion of the opening blade and an aft width dimension of an aft flared portion of the lower portion of the opening blade, the forward and aft width dimensions extending between the lower portions of the first and second sides, are greater than an intermediate width dimension of a waisted portion longitudinally extending contiguously between the forward and aft flared portions. 
     The first wing may be defined as being set back a first longitudinal distance from the leading edge and the second wing as being set back a second longitudinal distance from the leading edge. Thus, in one aspect of this design, the first longitudinal distance may be greater than the second longitudinal distance. Correspondingly, the first wing mounted to the first side of the blade at a first longitudinal location generally corresponding to the aft flared portion of the blade, and the second wing may be mounted to the second side at a second longitudinal location generally corresponding to the waisted portion of the blade. 
     In the wing design, an upper wing surface on the first and second wings extends aft over the corresponding first and second aft-opening wing apertures on aft cantilevered upper wing members. The lower wing surface on the first and second wings may form a first wedge angle of approximately 5° with the upper wing surface. Further, laterally outer-most wing surfaces extend between the upper and lower wing surfaces. The laterally outer-most wing surfaces may advantageously intersect the corresponding first and second sides of the blade at their corresponding first and second forward wing edges. Thus the laterally outer-most wing surfaces may form a second wedge angle of approximately 5° relative to the first and second sides of the blade respectively. Advantageously, the first and second wings may themselves also be inclined downwardly so that a pair of corresponding planes bisecting the wedge angle between the upper and lower wing surfaces on each of the first and second wings, where the pair of corresponding planes contain the corresponding forward wing edges, are inclined forwardly and downwardly at approximately 5° relative to a generally horizontal plane containing the lower surface, it being taken for the sake of this defined relationship that the lower surface is generally planar and horizontal, although this is not intended to be limiting, and is not necessarily so, notwithstanding that the preferred embodiment hereinafter described is illustrated as such. 
     The blade is mountable into a header member of a parallelogram linkage. A pair of parallel rigid drag arms extend between the header member and a hanger member and are pinned at their respective ends so that rotation of the header member relative to the hanger member on the parallel arms maintains a general horizontal orientation of the header member thereby supporting the blade downwardly in a constant orientation. The hanger member is mountable to a supporting frame. Selective actuation means such as a hydraulic actuator or selectively controllable spring assembly allows selective control of a downward force urging the blade into the soil. Where the selective actuation means is a hydraulic actuator mounted between the hanger member or frame and the parallel drag arms or header member, the actuating linkage may be selectively elevated so as to remove the blade from the soil. 
     In a preferred embodiment, a swivel mounted coulter wheel is mounted to a forward end of the header member, ahead of the leading edge of the blade when the blade is mounted to an intermediate or rear end of the header member. In a further alternative embodiment, a furrow closing arm, which may be a leaf spring arm, is mounted to a rear end of the header member so as to trail rearwardly therefrom in line with a furrow created by the blade passing through the soil. The closing arm may be urged downwardly by a selectively adjustable downward biasing means such as a pivotally mounted rocker arm pivotally mounted to a rear end of the header member and selectively adjustable so as to be rotated downwardly into downward biasing engagement against the furrow closing arm. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is, in exploded perspective view, the inline, subsurface seeding, fertilizing and watering blade of the system of the present invention. 
     FIG. 2 is a cross-sectional view along line  2 — 2  in FIG.  1 . 
     FIG. 3 is, in left side elevation view, the device of FIG.  1 . 
     FIG. 3 a  is, in left side elevation view, an alternative embodiment of the device of FIG.  3 . 
     FIG. 4 is, in bottom perspective view, the device of FIG.  1 . 
     FIG. 5 is, in rear elevation view, the device of FIG.  1 . 
     FIG. 6 is the view of FIG. 5 as the blade is passed through soil. 
     FIG. 7 is the rear elevation view of FIG. 6 with the blade removed for clarity so as to illustrate an approximation of the soil mechanics during an initial seed placing and fertilizing phase. 
     FIG. 8 follows on as a time-elapsed view of the view of FIG. 7, illustrating the collapse of the soil and lateral translation of the seeds following the initial phase. 
     FIG. 9 is, in a generally side perspective view, the actuating linkage of the in-line sub-surface seeding, fertilizing and watering system of the present invention, with the actuating linkage in a lowered position. 
     FIG. 10 is, in a rear perspective view, the actuating linkage of FIG.  9 . 
     FIG. 11 is, in a front perspective view, the actuating linkage of FIG.  9 . 
     FIG. 12 is the view of FIG. 9, with the actuating linkage elevated. 
     FIG. 13 is the linkage of FIG. 12 showing the coulter wheel and blade lowered into the soil. 
     FIG. 14 is an alternative embodiment of the actuating linkage of the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     As may be seen in FIG. 1, the no-tillage in-line sub-surface seeding, fertilizing and watering blade of the system of the present invention is depicted as opening blade  10 . Opening blade  10  has an upper, ported, mounting block  12  rigidly mounted atop a generally planar blade structure  14 . Blade structure  14  has a trunk  16  depending generally vertically beneath the upper ported mounting base or block  12 . Formed as part of the lower end of trunk  16  is a foot structure generally indicated by numeral  18 . 
     As also seen in FIGS. 2-5, mounting block  12  and blade  14 , including trunk  16  and foot  18 , are elongate in a generally vertical first plane A. The first plane includes longitudinal axis A′. With the exception of wings  20  and  22 , as better described below, the outer surface of trunk  16  smoothly merges into, so as to truncate in cross-section as, a waisted or foot-shaped lower surface  24 . In one embodiment access panels  26  and  28 , which conformally mount onto the lateral side walls of trunk  16 , are symmetrically shaped relative to the plane of symmetry of trunk  16 . The plane of symmetry of trunk  16  coincides with the first plane. 
     Upper ported mounting block  12  has ports  30 ,  32  and  34  formed in its upper surface. The ports extend downwardly through block  12  in cooperative alignment with corresponding channels  36 ,  38  and  40  extending downwardly in generally parallel spaced apart array through trunk  16 . Channel  40  also extends downwardly through foot  18 . 
     Channels  36  and  38  may, in one preferred embodiment not intended to be limiting, be formed by the alignment and snug adjacency of flanges  42  and  44  on the inner sides of access panels  26  and  28  respectively when the access panels are mounted conformally in opposed relation, to the lateral sides of trunk  16  so as to cover cavity  46  in trunk  16 . Access panel  26  may be mounted onto the port side of trunk  16  by means of tab  48  slidably engaging corresponding slot  50 , formed in the lower surface defining cavity  46 , so as to protrude downwardly into foot  18 . In a similar fashion, tab  52  on access panel  28  also slidably engages slot  50  when mounting access panel  28  onto the starboard side of trunk  16 . The upper ends of access panels  26  and  28  may be secured by releasable fasteners, for example a cooperating, flush-mounted nut and bolt pair (not shown) journalled through apertures  56 . 
     With access panels  26  and  28  mounted onto trunk  16 , so as to cooperatively align and abut flanges  42  and  44 , thereby completing forming and separation of channels  36  and  38 , channels  36  and  38  form a pair of chutes in cooperative alignment between ports  30  and  32  in mounting block  12  and corresponding lower outlet ports  58  and  60 . Lower outlet ports  58  and  60  are directed laterally oppositely and open into the respective interior ducts  62  and  64  formed within respective wings  20  and  22 . Interior ducts  62  and  64  open out into corresponding aft-facing apertures from under their respective wings  20  and  22  as better hereinafter described. 
     Toe  66 , which may be of a different and hardened material relative to the material forming mounting block  12 , trunk  16  and foot  18 , is rigidly mounted, by bolting or other means known in the art, to the forward portion of foot  18  so as to form a forwardly extending point or snout  68 , forwardly facing in the direction of forward translation B when the blade is translated in use. Advantageously, mounting block  12 , trunk  16  and foot  18  may be made of austempered ductile iron (hereinafter ADI) and toe  66  may be made of a chrome alloy. Access panels  26  and  28  and wings  20  and  22  may also be made of ADI. 
     Channel  40  is formed within and alone the rear or aft edge of trunk  16  and foot  18  so as to form a continuous generally linear conduit between port  34  and rear aperture  70 . Advantageously, the rear-most end of foot lower surface  24  is upturned for example as to provide aperture  70  with an opening generally perpendicular to the longitudinal axis of channel  40 . Further advantageously, channels  36 ,  38  and  40  are generally parallel so as to be raked aft in a downward direction from ports  30 ,  32  and  34 . 
     Wings  20  and  22  are each shaped as truncated wedges or otherwise as what may be described as irregular pyramid shapes wherein the vertex of each wedge or pyramid is aligned so as to be forward facing (in direction B) with the wedge diverging aft so as to form correspondingly shaped interior ducts  62  and  64  opening aft through the base of the wedges. In one preferred embodiment, the acute angles alpha (α)and beta (β), formed at the vertex of the wedges forming wings  20  and  22 , are each approximately 5 degrees. In the preferred embodiment upper surfaces  20   a  and  22   a , lateral surfaces  20   b  and  22   b , and lower surfaces  20   c  and  22   c  of wings  20  and  22  respectively are each generally planar. In one embodiment such as seen in FIG. 3 a , upper surfaces  20   a  and  22   a  are inclined forwardly further downwardly relative to the plane containing foot lower surface  24 , thus a plane II bisecting angle β would in this embodiment advantageously form an angle of approximately 5° relative to the plane F containing lower foot surface  24 . 
     Upper surfaces  20   a  and  22   a  extend aft and are cantilevered outwardly over the aft apertures of interior ducts  62  and  64 . The aft apertures of interior ducts  62  and  64  are advantageously formed by reducing the longitudinal length of lateral side walls  20   b  and  22   b  and raking the rearmost edge of lower surfaces  20   c  and  22   c  so as to extend them contiguously aft from the rear edge of lateral side walls  20   b  and  22   b  respectively to blend with foot  18 . 
     In the preferred embodiment, foot  18  is curvaceously waisted along its longitudinal length so as to form between curved side walls a forward expanded lateral dimension  72  smoothly tapering into a reduced lateral dimension  74  corresponding to the waisting and, progressing aft, a gentle flaring to an aft expanded lateral dimension  76 . In the preferred embodiment the waist of foot  18  approximately corresponds, in the longitudinal direction of axis A′, to the position of the forward ends of wings  20  and  22 . 
     In use, blade  16  is translated in direction B through soil  78 . As seen in FIG. 6, blade  16  is driven forwardly and positioned as better hereinafter described so as to maintain wings  20  and  22  submerged at a shallow depth below the surface of soil  78 . Such motion opens the soil upwardly from point  68  on toe  66  upwardly along the leading edge of foot  18  and blade  16  causing a small lifting and separating of soil  78  in opposite directions C. As blade  16  translates through the soil, material fed into ports  30 ,  32  and  34  flows under the force of gravity through respective channels  36 ,  38  and  40 . Material flowing through channel  40  exits through aperture  70  at the lowermost position of the narrow furrow  80  seen in FIG. 7 formed in soil  78  by the passing of blade  14  therethrough. The passing of wings  20  and  22  through soil  78  form shelves  82  in the soil as the soil is displaced by the wings so as to form shoulders  84  approximated in the illustration of FIG.  7 . 
     The forward movement in direction B of blade  14  through soil  78  draws material such as fertilizer  86  from aperture  70 , and also draws material such as seeds  88  from ducts  62  and  64  as the seeds are fed from channels  36  and  38  through outlet ports  58  and  60  respectively. 
     It has been found that the passing of wings  20  and  22  and the passing of foot  18  in their form as described herein, causes a fluid-like circulation in direction D of soil  78  aft of wings  20  and  22 . It is understood that the view of FIG. 7 is an approximation of the cross-section through the soil immediately behind blade  14  as it is translating through the soil. The soil, acting in a fluid manner, collapses so as to drop down shoulders  84  as the soil beneath shelves  82  is circulated in counter-rotation in direction D. Applicant has found that this circulation transports seeds  88  laterally outwardly along shelves  82  so as to facilitate advantageous lateral spacing apart of seeds on either side of furrow  80  separated both laterally and vertically from fertilizer  86  so as to inhibit chemical burning of the seeds for example by reason of the spacial relationship approximated by the illustration of FIG.  8 . 
     It is understood that the order and type of materials introduced into ports  30 ,  32  and  34  may be changed as would be known to one skilled in the art so as to introduce, for example, seeds through ports  30  and  32  and water through port  34 . A person skilled in the art would also understand that ports  30 ,  32  and  34  would have to be attached by appropriate conduits to corresponding hoppers or reservoirs carried, for example on a tractor (not shown). 
     In the preferred embodiment, although not intended to be limiting, certain planes assist in defining the relationship of the elements of the present invention relative to one another as described above and claimed hereinbelow. Firstly, blade structure  14  is generally bisected by a first plane A, referred to above as coinciding with the plane of symmetry of trunk  16 , which contains both the axis A′ and the cross-sectional view reference line  2 — 2  seen in FIG.  1 . The cross-sectional view of FIG. 2 is a view through a cutaway along first plane A. A second plane E is the plane containing the edges of aperture  70  at the lowermost end of channel  40 . A third plane F is the plane containing foot lower surface  24 . A fourth plane G is the plane containing the upper surface of mounting block  12 . Lastly, a wing bisecting plane H bisects wing  20  by bisecting angle beta. A corresponding parallel wing bisecting plane bisects wing  22  by bisecting the corresponding angle on wing  22 . 
     As seen in FIGS. 9-13, blade  10  is mounted to an actuating linkage  10  whereby the blade may be lowered into the soil  78  or elevated out of contact with soil  78 . 
     Actuating linkage  110  is a parallelogram linkage for displacement in direction I of header box  112  relative to hanger brackets  114 . Header box  112  is pivoted relative to hanger brackets  114  on pivotally mounted upper drag arm  116  and lower drag arms  118 . Each opposite end of the upper and lower drag arms are pivotally mounted by means of pins, bolts or the like. Thus upper drag arm  116  is mounted at one end between opposite halves  114   a  and  114   b  of hanger brackets  114  by means of pin  120 . The opposite end of upper drag arm  116  is mounted between the upper curved forks of header box  112  by means of pin  122 . 
     Lower drag arms  118  include an opposed pair of parallel rigid arms  118   a  and  118   b  each pinned at the corresponding lower ends of hanger brackets  114  by means of a pair of pins  124 . As better seen in FIG. 11, arms  118   a  and  118   b  of lower drag arm  118  are rigidly coupled to each other by back plate  126 . The opposite end of lower drag arm  118  is pivotally mounted to header box  112  by means of bolts  128 . 
     Scalloped coulter wheel  130  is rotatably mounted on mounting fork  132  by means of mounting plate  133 . Depth wheel  134 , mounted on one side of coulter wheel  130 , controls the depth of the blade in soil  78 . 
     Mounting fork  132  is free to swivel in direction J on shaft  136 . Shaft  136  is rotatably mounted in collar  138  on leading end  112   c  of header box  112 . 
     The parallelogram linkage of upper drag arm  116  and lower drag arms  118  and header box  112  are actuated so as to rotate in direction I about hanger brackets  114  by, in one embodiment, selective actuation of hydraulic ram  138 . Hydraulic ram  138  is fed by high pressure hydraulic line  140 . The upper end of hydraulic ram  138  is rigidly mounted to hanger brackets  114 . The lower end of hydraulic ram  138  is pivotally mounted to spacer block  142  by means of pinned coupling  144 . Spacer block  142  is rigidly mounted between lower drag arm members  118   a  and  118   b . Extension of hydraulic ram  138  causes rotation of the upper and lower drag arms downwardly about pins  120  and  124  on hanger brackets  114 . Retracting hydraulic ram  138  rotates the upper and lower drag arms upwardly. Thus with blade  10  mounted by means of mounting block  12  to header box  112  between fork arms  112   a  and  112   b  by, for example, means of bolted bracket  146 , the lower end of blade  10  may be selectively depressed below the surface of soil  78  so that blade  10  follows the ground breaking engagement of coulter wheel  130  with the soil. 
     In an alternative embodiment seen in FIG. 14, hydraulic ram  138  is replaced with leaf spring assembly  147 . An upper forward end of leaf spring assembly  147  is mounted between hanger brackets  114  by means of mounting brackets  148 . A lower rearward end of main spring  150  is rigidly mounted, for example, by means of bracket  152  to upper drag arm  116 . Preferably, a secondary leaf spring  154  is pivotally mounted to upper ends of mounting brackets  148  so that tightening in direction K of threaded shaft  156  by rotation of handle  158  forces the lower rearward end of secondary leaf spring  154  downwardly in direction L against the upper surface of mainspring  150 . This applies the downward pressure also in direction L against the parallelogram linkage of upper drag arm  116  and lower drag arm  118  so as to press blade  10  (not shown in FIG. 14) into engagement with the soil. The magnitude of the downward pressure applied by leaf spring assembly  146  onto blade  10  is adjusted by tightening or loosening threaded shaft  156  against main spring  150 . 
     As blade  10  is dragged in direction B through soil  78  a furrow  80  is created as described above. In one embodiment of the present system, a closure assembly  160  is mounted between fork arms  112   a  and  112   b  on header box  112 . Closure spring arm  162  is pivotally mounted at its upper forward end between fork arms  112   a  and  112   b . The lower rearward end of closure spring arm  162  is free to hand down into engagement with the upper surface of furrow  80  formed behind blade  10  as blade  10  passes through soil  78 . Downwards pressure is applied to closure spring arm  162  by means of rocker arm  164  and ratchet arm  166 . Rocker arm  164  is pivotally mounted between fork arms  112   a  and  112   b  by means of pinned shaft  168 . A releasable lock  170  is pivotally mounted to the upper end of rocker arm  164  by means of pin  172 . Releasable lock  170  may be loosened, for example by means of a nut and bolt coupling so that lock  170  may be selectively slid along ratchet teeth  174  and lock  170  resecured once the upper end of rocker arm  164  has been slid to a desired position outwardly along ratchet arm  166 . As seen in FIG. 10, the upper end of releasable lock  170  may be a threaded shaft or bolt  176  protruding upwardly through a slot  178  which extends substantially the length of ratchet arm  166 . Ratchet arm  166  is pivotally mounted to the upper ends of fork arms  112   a  and  112   b  by means of pin  113 . In particular, the base end of ratchet arm  166  is rigidly mounted to a base coupling bracket  180 , and it is base coupling bracket  180  which is pinned by pin  123  between the fork arms. 
     Selectively positioning the upper end of rocker arm  164  outwardly in direction M along ratchet arm  166  rotates rocker arm  164  downwardly relative to header box  112  about pinned shaft  168  so as to apply a downward pressure against the upper surface of closure spring arm  162 . This applies a greater downward pressure to the lowermost rearward end of closure spring arm  162  which in turn applies a greater pressure in closing furrow  80 . 
     As better seen in FIG. 11, each of the two mirror image components  114   a  and  114   b  making up hanger brackets  114  are in fact each a parallel assembly of two plates. Thus, for example, with respect to component  114   a , it is made up of an inner plate  114   a ′ and an outer parallel plate  114   a ″. Similarly, component  114   b  is made up of an inner plate  114   b ′ and a parallel outer plate  114   b ″. The inner and outer plates are rigidly spaced apart by means of identical spacer blocks  114   c  rigidly mounted between the inner and outer plates. Spacer blocks  114   c  provide rigid mounting surfaces so that hanger brackets  114  may be rigidly mounted to, for example, bar  182 , shown in dotted outline, by u-shaped brackets  184 . 
     In the preferred embodiment, bar  182  extends laterally across a supporting frame structure so that a laterally spaced apart array of actuating linkages  110  may be mounted across bar  182 . Thus, in the preferred embodiment, the supporting frame structure supporting bar  182  is preferably mounted on wheels so that the entire structure may be towed or mounted to a tractor or the like thereby simultaneously pulling a laterally spaced apart array of blades  10  through soil  78 . 
     As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.