looking at fig1 , there is shown a shank type seed drill apparatus 10 having a central portion 14 and having a left wing portion 16 having two frames 20 . the apparatus 10 has a right wing portion ( not shown ) that is a mirror image of the left wing portion 16 . the left wing portion 16 may be upwardly folded for transport using arm 18 . likewise , the right wing portion may be upwardly folded for transport . each frame 20 includes a forward frame section 30 with tillers 12 and a rearward frame section 40 with tillers 12 . the apparatus 10 is connected to a tractor in a conventional manner and has an axis a in a direction of movement of the apparatus 10 when tilling a field . in fig2 and 3 , there is shown one frame 20 of the apparatus 10 , with the tillers removed for clarity . the forward frame section 30 includes a front transverse tube 31 and a rear transverse tube 32 connected by supports 33 . angled frame members 35 and 36 are connected to the top of the front transverse tube 31 and the rear transverse tube 32 to form the forward frame section 30 . the forward frame section 30 also features lugs 38 at the front end for mounting to a rockshaft 24 , which in turn is mounted to boom 22 , so that motion of a hydraulic cylinder 26 rotates the rockshaft 24 resulting in vertical elevation change of the frame 20 . a link 27 is attached to a lever 28 on the rockshaft 24 to translate motion of press wheel gangs 50 , 57 , 64 at rear ( which are described below ) so this vertical motion is parallel with the ground and synchronized front to rear . a journal 39 at the rear of the triangle formed by the forward frame section 30 is oriented horizontally and parallel to the direction of travel . the mount for the hydraulic cylinder actuator 26 is positioned near the vortex of the triangle . the rearward frame section 40 includes a front transverse tube 41 and a rear transverse tube 42 connected by supports 43 . it can be seen that the front transverse tube 31 , the rear transverse tube 32 , the front transverse tube 41 and the rear transverse tube 42 are constructed in two sets to mount ground - working tools ( such as tillers 12 ) in typical staggered configuration . the rearward frame section 40 attaches to the forward frame section 30 on the journal 39 so it can rotate relative to the forward frame section 30 in radial directions r 1 ( see fig3 ) approximately 10 degrees in either direction . links 37 attach pivotally to lugs on both the forward frame section 30 and the rearward frame section 40 . as the apparatus 10 is working , draft loads are carried through these links 37 as well as through the thrust surfaces of the connecting journal 39 . the action of the forward frame section 30 and the rearward frame section 40 is not dependent on these links 37 ; they are present as a stabilizer and companion draft link . referring to fig3 , press wheel gangs 50 , 57 , 64 are connected to the rearward frame section 40 by crossbar 44 and bars 45 , 46 and 47 , which pivot about journals 54 , 61 , 68 on rear transverse tube 42 , when actuated by the rockshaft 24 . crossbar 44 has an axis b in direction of movement of the apparatus in a field . as even contact with the soil is necessary for successful planting , a section of this size includes three separate press wheel gangs . left outer press wheel gang 50 includes mounting arm 51 and press wheels 53 suspended from the mounting arm 51 by mounting brackets 52 . middle press wheel gang 57 includes mounting arm 58 and press wheels 60 suspended from the mounting arm 58 by mounting brackets 59 . right outer press wheel gang 64 includes mounting arm 65 and press wheels 67 suspended from the mounting arm 65 by mounting brackets 66 . referring to fig3 , press wheel gangs 50 , 57 , 64 are connected to the rearward frame section 40 by crossbar 44 and bars 45 , 46 and 47 , which pivot about journals 54 , 61 , 68 on rear transverse tube 42 , when actuated by the rockshaft 24 . crossbar 44 has an axis b in direction of movement of the apparatus in a field . as even contact with the soil is necessary for successful planting , a section of this size includes three separate press wheel gangs . left outer press wheel gang 50 includes mounting arm 51 and press wheels 53 suspended from the mounting arm 51 by mounting brackets 52 . middle press wheel gang 57 includes mounting arm 58 and press wheels 60 suspended from the mounting arm 58 by mounting brackets 59 . right outer press wheel gang 64 includes mounting arm 65 and press wheels 67 suspended from the mounting arm 65 by mounting brackets 66 . turning now to fig4 , there is shown a mechanism by which the middle press wheel gang 57 may move vertically in directions r 3 in order to maintain contact with the soil , while maintaining its share of the total weight carried by the press wheels and cross bar 44 . specifically , there is provided a parallel arm linkage assembly indicated generally at 70 . weldment 72 is journalled to crossbar 44 with pins 73 ( the left pin not being shown ). compression strut 74 applies pressure through pin 75 , causing weldment 72 to rotate and apply downward pressure to packer mount journal housing 76 through pin 77 . in journal housing 76 , pin 80 mounts a sleeve 81 that is arranged in hole 82 in mounting arm 58 . the distance between pin 73 and 75 centerlines can be varied by adjusting bolt 79 , so that middle press wheel gang 57 can receive its correct share of the total packer load regardless of its width ( at times it is not exactly ⅓ of the total press wheel set width , depending on spacing configurations ). the relationship of the distance between pins 73 and 75 and pins 73 and 77 is such that the majority of the thrust load from strut 74 results in a vertical load on the press wheel frame , while a proportionate amount is applied the middle press wheel gang 57 throughout its allowed vertical travel . fig5 and 6 show the wheel gangs 50 , 57 and 64 at their extremes of vertical travel . a further feature of the apparatus 10 is the adjustable weight transfer device 86 shown in fig7 and 8 . there is shown a side view of the support 33 and the front transverse tube 31 of the forward frame section 30 , which is connected to the boom 22 by rockshaft 24 . the rockshaft 24 is connected to the boom 22 at journal 87 , and the forward frame section 30 is connected to the rockshaft 24 at journal 88 , so retraction of the cylinder 26 results in lowering the forward frame section 30 from its upward position as shown in fig7 to its working position as shown in fig8 . the apparatus 10 has a heavy boom 22 . at times , it is advantageous to apply heavy packing pressure to the press wheels 53 , 60 , 67 , so the device 86 is used to transfer the weight of the boom 22 to the rear press wheel gangs 50 , 57 and 64 . this is done by creating a link that induces a high lateral force between journal 89 on boom flange 90 and pivot pin 91 that is connected to the forward frame section 30 . as rockshaft 24 lowers forward frame section 30 to its working position , linkage 92 and linkage 93 approach but do not reach alignment . a spring assembly 94 , which serves as a biasing means and includes spring 106 , is mounted at its lower end 102 by pin 96 to a lug 34 that is attached to the front transverse tube 31 of the forward frame section 30 . bolt 104 extends through the spring assembly 94 . a flange 101 extends downward from linkage 93 and is journaled by pivot pin 95 to the lower end 102 of the spring assembly 94 . the spring 106 exerts a growing pressure on linkage 93 by way of pivot pin 95 and flange 101 as rockshaft 24 lowers forward frame section 30 to its working position . this downward spring pressure translates to a high net lateral force through flange 90 and pivot pin 91 . as a result , the left wing section 16 tries to rotate about journal 87 on the boom 22 . this force in turn applies weight to the hitch of the tractor and to the press wheels 53 , 60 and 67 . to adjust the amount of force , the length of spring 106 can be changed with adjustment nut 97 on top of compression plate 111 , stopped bolt 98 can be adjusted , or the relationship of the linkages 92 and 93 can be lowered to close to parallel as this ratio determines the lateral force component . a stop is also provided to limit the linkage of going into a locking position as this could cause damage when the wing is raised out of working position . the linkage is arranged so that the force diminishes when raising the apparatus at headlands , going to zero when winging up for transports , and does not cause any extra loading on the rockshaft , while providing the operator with a range of adjustment to optimize the packing pressure of the apparatus . therefore , the present invention provides a tillage apparatus that provides improved frame flexibility such that the rear press wheels can more closely follow the contours of the ground , that provides improved weight distribution for the rear press wheels , and that provides adjustable weight transfer to the rear press wheels . the tillage apparatus thereby provides for more even seed insertion and soil compaction . although the present invention has been described in detail with reference to certain embodiments , one skilled in the art will appreciate that the present invention can be practiced by other than the described embodiments , which have been presented for purposes of illustration and not of limitation . therefore , the scope of the appended claims should not be limited to the description of the embodiments contained herein .
a tillage apparatus including a frame having tillers , land wheels supporting the frame , and press wheels on the frame is disclosed . in one form , the frame has a forward section and a rearward section supporting the press wheels . the rearward section can pivot radially with respect to the direction of movement of the forward section . in another form , the frame includes a linkage assembly connected to the rearward section . an inner wheel support gang having press wheels is attached to a pivoting mounting bracket of the linkage assembly such that the inner wheel support gang can pivot vertically . in another form , the apparatus includes a weight transfer device including a linkage connecting a boom and the forward section . a biasing means pivotally connected to the forward section and to the linkage distributes weight from the boom to the forward section to the rearward section and to the press wheels .