Abstract:
A ground engaging apparatus ( 10 ) has a support plate ( 50 ) pivotally attached to a frame ( 100 ); a pair of arms ( 30, 40 ) interconnecting the support plate ( 50 ) and a shank support ( 60 ), which supports a shank ( 70 ) and ground follower ( 90 ) and first and second biasing rams or springs ( 200, 300 ), to maintain the ground follower ( 90 ); against the ground ( 91 ) but allow controlled break out of a ground opening, or tillage, tool ( 81 ) if an obstruction is engaged.

Description:
FIELD OF THE INVENTION 
   THIS INVENTION relates to agricultural apparatus, namely a ground engaging apparatus. The ground engaging apparatus is particularly suitable for, but not limited to, tillage applications and non-till seed planting. 
   BACKGROUND OF THE INVENTION 
   When planting seeds, in particular for large scale applications such as a commercial farm, a ground engaging apparatus such as a planter apparatus may be towed behind a tractor to cut channels or furrows into the soil which is followed by planting of a seed within the channel. Usually, a plurality of planter units are attached to a support towing bar that aligns the planter units at selected distances apart from each and the support bar is attachable to a tractor via a tow bar. 
   The ground engaging unit may comprise a frame having a pivotable parallelogram arrangement that maintains a ground opening tool in the ground while traversing level and uneven ground. A spring located between two pivotable arms of the parallelogram applies a force that maintains the ground opening tool at a pre-selected depth in the soil as the ground engaging unit encounters inclines and depressions. When the ground engaging unit encounters an obstacle such as a rock or stump, the shank is pivoted upward and away from the obstacle by a break-away or breakout mechanism to thereby prevent damage to the ground opening tool. The break-away mechanism comprises a spring that applies a force independent of the parallelogram as a separate break-away unit. 
   A ground engaging apparatus described in Australian patent AU 1996 60854 B2 (714157) (Techsearch Incorporated) comprises a single bias means for adjusting both a downward force to maintain the ground opening tool in the soil at a selected depth and a break-away force that maintains the ground opening tool in the soil unless the planter unit encounters an obstacle. This design is limited in that adjusting the downward force on a parallelogram arrangement also adjusts the break-away force, which is undesirable in situation where a user wishes to adjust each force independently of the other. Also, a minor adjustment of the bias means to the downward force of the parallelogram has a significant affect on the break-away force, which may result in excessive break-away force applied to the ground opening tool. 
   SUMMARY OF THE INVENTION 
   It is an object of the invention to provide an alternative or improvement to the abovementioned background art. 
   In a first aspect, the invention provides a ground engaging apparatus comprising: 
   (i) a frame; 
   (ii) a support plate pivotally attached to the frame about a first point; 
   (iii) a first bias member attached at a first end to the frame and attached at a second end to the support plate; 
   (iv) at least two arms each pivotally attached at respective first ends to the support plate; 
   (v) a shank support to which respective second ends of the at least two arms are pivotally attached; 
   (vi) a second bias member attached at a first end to the frame and attached at a second end to one arm of the at least two arms; 
   (vii) a shank attached to the shank support; 
   (viii) a ground opening tool attached to a free end of the shank opposite the shank support; and 
   (ix) a ground follower attached to the shank support; 
   wherein: 
   said first bias member applies a first force to the support plate urging the support plate to rotate about the first point to thereby abut a stop that obstructs rotation thereof until a counter force is applied against the ground follower or ground opening tool that is greater than the first force such that the support plate rotates about the first point in a direction away from the stop; and 
   the second bias member applies a second force to the one arm thereby urging the ground follower against a surface and the ground opening tool into the surface. 
   Preferably, the apparatus comprises two arms. 
   Preferably, the ends of the two arms define pivotable corners of a parallelogram arrangement comprising linkages respectively comprising the two arms, the support plate and the shank support, each of which define a side of the parallelogram and respectively capable of uniform movement. 
   Preferably, a point at which the second end of the first bias member attaches the support plate and the respective first ends of the two arms define a first linkage of the parallelogram. 
   Preferably, the respective second ends of the two arms and the shank support comprise a second linkage of the parallelogram. 
   More preferably, the second linkage further comprises the ground follower and ground opening tool. 
   Preferably, the first ends of the respective two arms are capable of being vertically aligned. 
   Preferably, the second ends of the respective two arms are capable of being vertically aligned. 
   Preferably, the second bias member is attached intermediate the one arm. 
   Preferably, the first point is located intermediate the stop and the point at which the second end of the first bias member attaches to the support plate. 
   Preferably, the first bias member and second bias member each comprise a coiled spring or hydraulic cylinder. 
   More preferably, the first bias member is a coiled spring and the second bias member is a hydraulic cylinder. 
   Preferably, the first force of the first bias member and the second force of the second bias member are independently adjustable. 
   Preferably, the ground follower is located in front of the shank and below the at least two arms. 
   Preferably, the ground follower comprises a wheel. 
   Preferably, the frame comprises a towing attachment for attaching to a tow bar. 
   Preferably, one or more apparatus are attached to a tow bar via the towing attachment. 
   Preferably, the surface is a surface of ground for cultivation. 
   In a second aspect, the invention provides a ground engaging assembly comprising a plurality of ground engaging apparatus of the first aspect each attached to a same tow bar. 
   Preferably, the ground engaging assembly further comprises a seed dispenser located adjacent to each ground opening tool such that in use one or more seed may be placed within a channel formed in the ground by the ground opening tool. 
   More preferably, the seed dispenser is located behind the ground opening tool at an end opposite a cutting end. 
   It will be appreciated that the present invention comprises at least two bias members for respectively providing a downward force to maintain the ground opening tool in the ground when traversing level, risen or depressed ground and a breakout force that maintains the ground opening tool in the ground unless an obstruction or obstacle is encountered. The invention preferably has the advantage of adjusting the downward force and breakout force independently of each other. The invention in a preferred embodiment combines the two bias members in a compact and efficient configuration such that both bias members are located in front of a wheel or ground follower as described herein. 
   Throughout this specification unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of the stated integers or group of integers or steps but not the exclusion of any other integer or group of integers. 

   
     DESCRIPTION OF THE DRAWINGS 
     In order that the invention may be readily understood and put into practical effect, preferred embodiments will now be described by way of example with reference to the accompanying drawings wherein like reference numerals refer to like parts and wherein: 
       FIG. 1  shows a side view of a ground engaging apparatus of the invention on level ground and first bias member in phantom; 
       FIG. 2 . shows a side view of the ground engaging apparatus traversing level ground without breakout; 
       FIG. 3  shows a side view of the ground engaging apparatus traversing a depression in the ground without breakout; 
       FIG. 4  shows a side view of the ground engaging apparatus traversing risen ground without breakout; 
       FIG. 5  shows a side view of the ground engaging apparatus retracted; 
       FIG. 6  shows a side view of the ground engaging apparatus traversing level ground in a breakout configuration; 
       FIG. 7  shows a side view of the ground engaging apparatus traversing a depression in a breakout configuration; 
       FIG. 8  is a side view of the ground engaging apparatus traversing risen ground in a breakout configuration; 
       FIG. 9  is a line diagram of the ground engaging apparatus traversing level ground without breakout; 
       FIG. 10  is another representation of a line diagram of the ground engaging apparatus traversing level ground without breakout; 
       FIG. 11  is a line diagram of the ground engaging apparatus traversing a depression without breakout; 
       FIG. 12  is a line diagram of the ground engaging apparatus traversing risen ground without breakout; 
       FIG. 13  is a line diagram of the ground engaging apparatus traversing level ground with breakout; 
       FIG. 14  is a line diagram of the ground engaging apparatus traversing a depression with breakout; 
       FIG. 15  is a line diagram of the ground engaging apparatus traversing risen ground with breakout; and 
       FIG. 16  is another diagram illustrating preferred structures and applied forces of the ground engaging apparatus. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Terms used herein when referring to an item or integer are not intended to suggest or imply any limitation to the structure or function of the item or integer. 
     FIG. 1  shows a side view of a ground engaging apparatus  10  comprising a support plate  50 , a shank support  60  and two arms  30 ,  40  each pivotally attached at opposites ends to said support plate  50  and shank support  60  thereby forming sides of a parallelogram  35 . Attachment points A, B, C and D of ends of arms  30 ,  40  generally define corners of the parallelogram  35 . Accordingly, plate  50  and shank support  60  effectively form part of the parallelogram  35 . A shank  70 , also referred to as a tine, tyne, tine shank or tyne shank, is attached to the shank support  60  and is adjustable relative thereto by loosening and tightening bolts  61 . A ground opening tool  80  that is adapted to disrupt the ground  91 , preferably forming a channel suitable for planting seeds, is attached to the shank  70  at a free end opposite the shank support  60 . A ground follower  90 , shown as a wheel, is attached to shank support  60  and located in front of the ground opening tool  80  at a leading end digging tip  81  of the ground opening tool  80 . The wheel  90  contacts the ground  91  as shown and in use assists with guiding and positioning the ground engaging apparatus  10 , in particular the ground opening tool  80 . 
   The support plate  50  is pivotally attached to a frame  100  at attachment point A (also referred to herein as a first point). A first bias member  200  is attached to the support plate  50  at pivotable attachment point E and attached to the frame  100  at point  220  as shown in  FIG. 1 . The first bias member  200  applies a downward force, referred to herein as an applied breakout force, against plate  50  that is countered by stop  210  when there is no reaction or counter breakout force applied to the ground opening tool  80  as discussed hereinafter. Point A is preferably located intermediate the stop  210  and point E, where the first bias member  200  attaches to the support plate  50 . Adjusting the distance of the pivot point A to the stop  210  and point E preferably adjusts a force applied by the second bias member  200  about point A. A second bias member  300  is attached at a first end  310  to the housing  100  by member  110  and at a second end  320  to arm  40  as shown in  FIG. 1 . The second bias member  300  applies a downward force onto the parallelogram  35  at point  320 , which is preferably intermediate arm  40 . The applied downward force directs the ground opening tool  80  into the ground  91  and is countered by the ground follower  90 . 
   One or more ground engaging apparatus  10  may be attached to a towing cross bar via towing attachment  400  thereby forming a ground engaging assembly. It will be appreciated that preferably there are a plurality of ground engaging apparatus  10  attached to a towing cross bar, which is attachable to a tractor, car, truck, horse, mule, ox or other means for pulling the ground engaging apparatus  10 . Preferably, a seed dispenser  82  such as a planting tube  83  is located adjacent to the ground opening tool  80  so that one or more seeds may be deposited within a channel or furrow  92  cut by the ground opening tool  80  when in use. Other substances may be deposited into the channel  92 , for example fertiliser and the like. 
     FIGS. 2 to 5  and  10  to  12  show side views and line diagrams of the ground engaging apparatus  10  in various configurations when traversing different ground levels and when retracted. In these configurations, points A and C are substantially vertically aligned and points B and D are substantially vertically aligned as shown and arms  30 ,  40  pivot about points A, B, C and D. First bias member  200  maintains a constant applied downward breakout force that is countered by stop  210 . The second bias member  300  applies a downward force against the parallelogram  35  and a change in ground elevation  91  results in extension and retraction of a hydraulic cylinder of the second bias member  300 . 
   The parallelogram  35  is defined by points A, B, C and D and sides of the parallelogram comprise arms  30 ,  40 , support plate  50  and shank support  60 . As shown in  FIGS. 10-15 , points E, A and C form a first single linkage that is capable of uniform movement and points B, D and shank  60  form a second single linkage that is capable of uniform movement. 
     FIGS. 2 and 10  show the ground engaging apparatus  10  in a configuration wherein the ground engaging apparatus  10  is on level ground. As shown, the arms  30 ,  40  are substantially parallel with the surface of the ground  91  and attachment points A and C are substantially aligned vertically with each other and attachment points B and D are also substantially aligned vertically with each other thereby forming a generally rectangular configuration of the parallelogram  35 . A downward second force  300   a  applied by second bias member  300  directs the ground opening tool  80  into the ground  91  and is countered by the ground follower  90 . An applied breakout first force  200   a  applies a force preventing the ground opening tool  80  from breakout unless a sufficient reaction breakout force  200   b  is encountered as described hereinafter. 
     FIGS. 3 and 11  show a ground engaging apparatus  10  in a configuration wherein the ground engaging apparatus  10  is traversing a depression in the ground. In this configuration, arms  30 ,  40  are pivoted downward thereby lowering points B and D respectively below points A and C. Points B and D are each attached to shank support  60  such that shank support  60  effectively forms an end of the parallelogram defined by points A, B, C and D. Accordingly, when the arms  30 ,  40  are lowered as shown in  FIG. 3 , shank support  60  is lowered thereby maintaining the ground opening tool  80  in the ground  91 . The shank  70  remains substantially vertical. The second bias member  300  is shown extended. 
     FIGS. 4 and 12  show the ground engaging apparatus  10  in a configuration when traversing risen ground  91 . The second bias member  300  is shown retracted and arms  30 ,  40  are angled upward such that points B and D are above respective points A and C as shown. 
     FIG. 5  shows the ground engaging apparatus  10  retracted such that the ground opening tool  80  no longer contacts the ground  91 . This is useful, in particular, when a plurality of ground engaging apparatus  10  are attached to a support towing bar and only selected ground opening tools  80  are in use. This may be suitable for example when adjusting spacing between planting rows of a crop. The present invention has the advantage of being compact in horizontal length, preferably when the ground opening tool  80  is retracted. As shown, the shank support  60  is lifted substantially vertically with minimum or no outward horizontal extension of the shank  70 . This provides a compact configuration of the ground engaging apparatus  10 , which is advantageous when compared with other ground engaging apparatus. For example, this configuration is preferred if seed boxes are fitted as the boxes are maintained horizontally level. 
     FIGS. 6 to 8  and  13  to  15  show the ground engaging apparatus  10  in a configuration wherein the ground opening tool  80  encounters an obstacle such as a rock, branch, stump or the like. It is desirable that the ground opening tool  80  is moved away from the ground  91  and obstacle or obstruction to prevent or minimise damage to any part of the ground engaging apparatus. This movement of the ground opening tool  80  away from the ground  91  is referred to herein as a “breakout” or “breakaway” as the support plate  50  is rotated about point A thereby moving an end  51  of the support plate  50  away from the stop  210 . The first bias member  200  applies a breakout force  200   a  as shown in FIGS.  9  and  10 - 15  that prevents the ground opening tool  80  from breaking away unless the ground opening tool  80  encounters a reaction force  200   b  greater than the applied breakout force  200   a  applied at point E by the first bias member. 
     FIGS. 6 and 13  show the ground engaging apparatus  10  in a breakout configuration when traversing level ground. An applied breakout force  200   a  prevents the ground opening tool  80  from breakout unless a sufficient reaction breakout force  200   b  is encountered, e.g. hitting an obstacle such as a rock or stump. When an obstacle is encountered, a reaction breakout force  200   b  shown in  FIG. 13  moves shank  70  as shown thereby shifting arm  30  rearward thereby causing the support plate  50  to rotate counter clockwise about point A. As the wheel  90  and shank  70  are attached to shank support  60 , the breakout force is transferred via a side of the parallelogram  35  defined by points B and D effectively as a single link as shown in  FIG. 13 . 
     FIGS. 7 and 14  show the ground engaging apparatus  10  in a breakout configuration when traversing a depression and  FIGS. 8 and 15  show the ground engaging apparatus  10  in a breakout configuration when traversing risen ground. Similar applied and breakout forces as previously illustrated are shown. 
     FIG. 16  shows another diagram representing the structural components of the invention with applied forces indicated. As shown in  FIG. 16 , a first bias member applies a dominant breakout force  200   a  to resist breakout away from abutment point  210 , which is represented in  FIG. 1  as stop  210 . The breakout force  200   a  is applied to a vertical link defined by points E, A and C, wherein point A is a fixed pivot point. A second bias means applies a smaller downward force  300   a  to the parallelogram  35 , preferably via arm  40 . The second bias member  300  provides independent adjustment of the downward force  300   a  without affecting the applied breakout force  200   a . In a preferred embodiment wherein the second bias member  300  comprises a hydraulic cylinder, another benefit is an ability to adjust the second bias member  300  without a need to manually adjust the mechanism. 
   First bias member  200  and second biased member  300  may comprise a spring, hydraulic cylinder or other bias member. Preferably, the first bias member  200  is a coiled spring and the second bias member  300  is a hydraulic cylinder as shown. Use of a hydraulic (or pneumatic) cylinder is advantageous in that adjustment of a force applied by the bias member may be performed remotely for one or more bias members by adjusting a fluid pressure. The fluid may be air, oil, water or any other suitable fluid. In a preferred form of the invention, in use a user is capable of driving a tractor that is towing one or more ground engaging apparatus  10  and the force of the first bias member  200  and/or second bias member  300  may be adjusted from the tractor without needing to manually adjusting an applied force for each bias member. 
   It will also be appreciated that the ground follower comprises a wheel, sled, cutting disc, roller or other suitable device. In one embodiment, the ground engaging apparatus comprises both a wheel and a cutting disc for slicing through weeds and other plant material in a path of the apparatus. 
   The ground opening tool comprises devises and configurations including for example seed shoes, plough shares, seed openers, furrow openers, disc openers, cutting edges and the like. It will also be appreciated that the present invention is preferably used with a seed dispenser such as a seed tube or planter tube that releases one or more seeds in a channel  92  formed by the ground opening tool  80 . Although there is no need to deposit any material in the channel, preferably seeds, fertiliser, wetting agent or other agricultural material is dispensed in the channel. The seeds may be for any crop, including for example, a vegetable or fruit including a cereal crop, wheat, rice, barley, corn, lettuce and the like. 
   Although the invention has been shown and described with exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto without departing from the scope of the invention. 
   The disclosure of each patent and other document referred to in this specification is incorporated by reference in its entirety.