as will be made apparent from the following description , the present invention provides an apparatus that automatically adjusts the position of an implement in response to changes in the position of the hitch of a tractor towing the implement . for purposes of description , the invention will be described with respect to a stack - fold planter , such as that shown in fig1 - 4 , but it is understood that the invention is applicable with other types of implements . the invention , which can also be embodied in an automated method , is designed to reduce the number of user inputs that were heretofore required to command movements of the implement , such as at headland turns . turning now to fig1 - 4 , a planting system 10 includes a stack - fold implement 12 , shown in a field working position , coupled to a prime mover 14 , e . g ., tractor , in a known manner . for purposes of illustration , the stack - fold implement 12 is a row crop planter , which as shown in fig2 , includes a frame 16 generally comprised of a center section 18 and wing sections 20 , 22 on opposite lateral sides of the center section . the center section 18 includes a tongue ( not shown ) that extends forwardly of the center section 18 for hitching the implement 12 to the prime mover 14 . as will be described more fully below , the implement 12 is coupled to a three - point hitch of the prime mover 14 . gauge wheels 24 on the frame sections 18 , 20 , and 22 set the seeding or cutting depth for the implement . in the illustrated embodiment , sixteen openers 26 are mounted to the frame 16 at equally spaced intervals , but it is understood that more than or fewer than sixteen openers could be mounted to the frame 16 . as known in the art , the wing sections 20 , 22 may be raised to a transport position , as shown in fig3 , in which the openers carried by the wing sections 20 , 22 are stacked over the center section 18 . as also known in the art , the openers 26 are designed to cut a furrow into the soil , deposit seed and / or fertilizer into the furrow , and then pack the furrow . seed boxes or “ mini - hoppers ” 28 are optionally mounted to each of the openers 26 . the mini - hoppers 28 are preferably smaller than conventional mini - hoppers used with stack - fold crop row planters and thus hold less material than conventional seed boxes . the smaller mini - hoppers are flow - coupled to a central bulk fill assembly 30 that delivers material , such as seed and / or fertilizer , to the openers 26 and / or the mini - hoppers 28 . the central bulk fill assembly 30 preferably includes a pair of bulk fill hoppers 32 and 34 supported adjacently to one another on a frame 36 . the frame 36 is coupled to the center section 18 by a set of rearwardly extending frame members 38 , 40 , and 42 connected to a crossbar 44 . in a preferred embodiment , the frame members 38 , 40 , 42 are removably coupled to center frame section 18 which allows the bulk fill assembly 30 to be removed from the implement 12 or added as an after - market add - on to an existing stack - fold implement . the frame 36 is supported above the work surface ( or transport surface ) by a pair of wheels 46 , 48 that are each connected to the frame by a wheel lift assembly 50 , which in the illustrated embodiment includes a pair of parallel linkages 52 , 54 . each linkage includes upper links 56 , 58 and lower link 60 , 62 , respectively . in addition to the links 56 - 62 , a pair of lift arms 64 , 66 are provided . lift arm 64 is coupled to frame member 42 at a knuckle 68 to which parallel linkage 52 is also connected . in a similar manner , lift arm 66 is coupled to frame member 38 at a knuckle 70 to which parallel linkage 54 is also connected . as shown particularly in fig4 , the frame 36 further includes a y - beam 72 that is pivotally coupled to the center frame member 40 . as is customary for most central bulk fill assemblies , an air blower 74 is mounted beneath the bulk fill hoppers and is operable transfer particulate matter from the hoppers 32 , 34 to the individual mini - hoppers 28 or directly to the openers 26 in a forced air stream . as known in the art , central bulk fill hoppers , such as those described above , provide the convenience of a central fill location rather than having to fill the individual seed boxes . also , the central fill hoppers have greater capacity than the seed boxes , which reduces the number of fill iterations that must be taken when planting . simply mounting a central bulk fill assembly to a stack - fold planter , such as planter 12 , can create stability issues , especially when the stack - told planter is in the transport position . in this regard , the present invention provides a mechanism for raising the bulk fill assembly 30 when the stack - fold planter 10 is in the folded , transport position . raising the bulk assembly 30 provides greater stability during transport as well provides increased clearance between the hulk fill assembly 30 and the roadway . a pair of hydraulic lift cylinders 76 and 78 are operable for lifting the frame 36 , and thus the bulk fill assembly 30 . cylinder 76 is interconnected between forward knuckle 68 and a rearward knuckle 80 . as shown in fig4 , the rearward knuckle 74 includes , or is coupled to , a mounting arm 82 that is coupled to axle 84 about which wheel 46 rotates . cylinder 76 includes a ram 86 that is coupled to the rearward knuckle 80 whereas cylinder 76 is coupled to the forward knuckle 68 . in a similar fashion , cylinder 78 includes a ram 88 connected to a rearward knuckle 90 whereas the cylinder 78 is connected to the forward knuckle 70 . it will be appreciated that a mounting arm 92 is connected to , or formed with , the rearward knuckle 90 , and the mounting arm 92 is connected to an axle ( not shown ) about which wheel 48 rotates . as known in the art , central bulk fill hoppers , such as those described above , provide the convenience of a central fill location rather than having to fill the individual seed boxes . also , the central fill hoppers have greater capacity than the seed boxes , which reduces the number of fill iterations that must be taken when planting . simply mounting a central bulk fill assembly to a stack - fold planter , such as planter 12 , can create stability issues , especially when the stack - fold planter is in the transport position . in this regard , the present invention provides a mechanism for raising the bulk fill assembly 30 when the stack - fold planter 10 is in the folded , transport position . raising the bulk assembly 30 provides greater stability during transport as well provides increased clearance between the bulk fill assembly 30 and the roadway . turning now to fig5 , the present invention provides a communications apparatus 94 for use with a prime mover equipped with iso 11783 technology . the communications apparatus 94 includes datalink 96 that communicatively links an implement electronic control unit ( ecu ) 98 with electronics 100 of the prime mover 14 . the datalink 96 may be a wireless connection or , as shown in fig5 , a wired communication consisting a connector 102 tethered by cable 104 to the electronics 100 and a receiver 106 tethered by cable 108 to ecu 98 . in a preferred embodiment , the connector 102 and the receiver 106 are iso 11783 components that permit the transfer of data between the prime mover electronics 100 and the ecu 98 . thus , it will be appreciated that the datalink 96 provides an isobus connection between the prime mover 14 and the stack - fold implement 12 . the isobus connection enables the transmission of various data between the stack - fold implement 12 and prime mover 14 . one type of data is hitch position information . the prime mover 14 has a hitch position sensor 110 that provides feedback to the electronics 100 of the prime mover 14 as to the vertical position of the coupling between the stack - fold implement 12 and the prime mover 14 . in one embodiment , this coupling is a three - point hitch . the prime mover electronics 100 provides a data signal to the ecu 98 via datalink 96 containing hitch position information . in accordance with one aspect of the invention , the ecu 98 adjusts the vertical position of the stack - fold implement 12 accordingly . more particularly , the stack - fold implement 12 has a frame position sensor 112 that measures the vertical position of the central bulk fill assembly 30 . in one preferred embodiment , the vertical position is determined from the angle between frame 36 and the wheel lift assembly 50 . it is contemplated that a number of sensors may be used to measure this angle including , but not limited to , rotary potentiometers , displacement sensors , optical sensors , strain gauges , pressure sensors , and the like . for example , in one embodiment , the frame position sensor 112 measures the displacement of either hydraulic lilt cylinder 76 or hydraulic lift cylinder 78 . the ecu 98 receives the frame position signal from the frame position sensor 112 and compares the frame position of the stack - fold implement 12 with the vertical position of the hitch , as provided in the hitch position signal . from this comparison , the ecu 98 raises or lowers the central bulk fill assembly 30 to level the central bulk fill assembly 30 in light of the changes in vertical position of the prime mover hitch . in one embodiment of the invention , the central bulk fill assembly 30 is raised or lowered by ecu 98 controlling operation of an electric over hydraulic valve 114 . the hydraulic valve 114 is interconnected between the hydraulics 115 of the prime mover 14 and the hydraulics of the stack - fold implement 12 , which include the pair of hydraulic lift cylinders 76 , 78 . thus , the hydraulic valve 114 , upon receipt of a corresponding command signal from the ecu 98 , can increase or decrease the pressure in the pair of hydraulic lift cylinders 76 , 78 to raise or lower , respectively , the central bulk fill assembly 30 . it is highly desirable to increase the elevation of the central bulk fill assembly 30 when the hitch is raised and , conversely , lower the elevation when the hitch is lowered . in a further embodiment of the invention , also shown schematically in fig5 , the wing sections 20 , 22 are moved automatically based on the vertical position of the three - point hitch . as known in the art , the hydraulic components , including lift actuators 116 , 118 are used to raise and lower the left wing section 22 (“ left side gull wing ”) and the right wing section 20 (“ right side gull wing ”), respectively . in this further embodiment , the ecu 98 also provides command signals to the left and right lift actuators , which can be of conventional design . in a preferred embodiment , the lift actuators are hydraulic cylinders whose operation is controlled by a valve , such as hydraulic valve 114 . as such , the ecu 98 provides control commands to the hydraulic valve 114 which in turn controls operation of the lift actuators preferably in synchrony with the wheel lift assembly 50 . it will be appreciated that the wing sections are movable between a field working position , such as illustrated in fig2 and a retracted or raised position , such as illustrated in fig3 . in the field working position , the wing sections ( as well as the center section ) are free to float so to respond to changes in surface contours . in this regard , the ecu 98 commands the electric over hydraulic valve 114 to control hydraulic fluid flow in the hydraulic system to move the wing sections to the float position when the hitch is in a fully lowered position . it will also be appreciated that in the embodiment illustrated in fig5 , the operator of the tractor , i . e ., towing vehicle , using conventional hydraulic remotes , pressurizes the tractor &# 39 ; s hydraulic system to which the hydraulics of the implement are flow - coupled and thus also pressurized . as such , the operator must manually operate the hydraulic remotes to supply the hydraulic power needed to operate the lift actuators for the gull wings and the central bulk fill assembly . in contrast , and referring now to fig6 , a communications apparatus 120 according to an alternate embodiment of the invention controls operation of the hydraulic remotes automatically , i . e ., uses the tractor hydraulics 122 to directly control operation of the wheel lift assembly 50 and the lift actuators 116 , 118 rather than control an electronic - over - hydraulic valve 114 . more particularly , the hitch position sensor 110 provides hitch position data to the implement ecu 98 across isobus connection 96 . the implement ecu 98 uses the hitch position information together with frame position data read from the frame position sensor 112 and provides control commands to the hydraulic remote ( s ) 124 , which are connected to the tractor hydraulics 122 in a known manner . the tractor hydraulics are flow - coupled to the actuators of the wheel lift assembly 50 and the lift actuators 116 , 118 . it is understood that the actuators could be independently flow coupled to the tractor hydraulics , but preferably , a single supply conduit 126 and return conduit 128 that are coupled to a manifold 130 or similar distribution device to which the actuators for the wheel assembly and the lift actuators are flow coupled in a conventional manner . it will thus be appreciated that in the embodiment illustrated in fig6 , the implement controls the hydraulics of the tractor based on commands transmitted to the tractor via the isobus connection . it will be appreciated that in one embodiment of the invention , the position of the tractor hitch is used to adjust the vertical position of the implement frame . it is understood however that in another embodiment , the vertical position of the implement frame could be monitored to cause automatic adjustment of the tractor hitch . many changes and modifications could be made to the invention without departing from the spirit thereof . the scope of these changes will become apparent from the appended claims .
a method and apparatus for automating some of the tasks that heretofore required operator action at headland turns or similar events are provided . the present invention automates operation of lift assist wheels and / or gull wings , such as those found on a stack - fold implement , based on the position of the tractor hitch to which the implement is coupled . an operator may control the position of the implement , such as at a headland turn , by raising and lowering the tractor hitch using a remote control . the invention enables the planter to compare the tractor hitch position relative to an implement position and control operation of the implement accordingly without additional user inputs .