Abstract:
An agricultural seeding implement has a seed hopper that is weighed continuously during field operations as the seed volume in the hopper progressively diminishes. The weight information is used to perform ongoing control functions on the implement. One embodiment uses the weight information to reduce the down pressure on compaction wheels of a wing section of the machine as a function of the diminishing weight of the hopper on the main section.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to agricultural seeders and, more particularly, to a seeder having the ability to weigh its seed hopper during on-going field operations and perform a control function as a response to determining the weight of the hopper. 
       BACKGROUND AND SUMMARY 
       [0002]    Agricultural seeders are typically provided with large bulk seed hoppers that carry the supply of seeds or other materials to be deposited in the soil as the seeder traverses a field. As the volume of seeds in the hopper diminishes, the hopper becomes progressively lighter and lighter, which produces several outcomes. For one thing, it means that seeds are in fact being distributed from the hopper, but that fact alone does not mean that they are being distributed at any particular rate, i.e., it does not mean that they are being distributed at the intended rate. Moreover, it means that at some point in time, the hopper will be depleted, but the mere fact that they are being depleted does not provide information as to when such depletion will occur. 
         [0003]    In multi-section cultivation seeders having a main section and one or more wing sections, each section is typically provided with its own set of compaction wheels that are located between cultivators at the front of the machine and openers at the back of the machine. The compaction wheels serve the dual purpose of providing rolling ground support for the seeder during its traverse of a field and compacting the soil turned over by the cultivators so it is in the best condition for engagement by the trailing openers. The main section carries the hopper; thus, as the seed supply diminishes in the hopper, the weight of the hopper diminishes and the down pressure applied against the ground by the compaction wheels on the main section likewise diminishes. However, the compaction pressure applied by the wing section wheels is unaffected by changing conditions on the main section and thus soon becomes greater than that of the main section compaction wheels. This non-uniform compaction pressure across the width of the machine can produce a number of undesirable outcomes including, for example, unequal planting depths and uneven seed emergence. 
         [0004]    Accordingly, the present invention advantageously utilizes the decreasing weight of the seed hopper due to diminishing seed supply to perform one or more valuable control functions on the seeder in response to such change. For example, the decreasing weight can be used to calculate the actual amount of product applied over a given area, which is then compared with the intended amount. If the deviation between the two values is greater than a set point, an error message can be displayed at a monitor on the tractor to inform the operator. Another function is to calculate and display the estimated time of depletion, based upon the rate of depletion determined by comparing the weight at known time intervals. A further function is to reduce the down pressure applied by compaction wheels on one or more wings of the machine as a function of the decreasing weight of the hopper (and consequent decreasing down pressure applied by the main section compaction wheels) in an effort to maintain uniform compaction wheel pressure across the entire width of the machine. In a preferred embodiment of the invention, the instantaneous weight is sensed by load cells that mount the hopper on the main frame section. A controller receives weight signals from the load cells, along with signals from a pressure transducer that senses instantaneous wing cylinder hold down pressure, processes the signals and causes appropriate reduction in the wing cylinder hold down pressure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a left rear perspective view of an exemplary cultivation seeder constructed in accordance with the present invention; 
           [0006]      FIG. 2  is a left side elevational view of the seeder with the tools in a lowered field working position; 
           [0007]      FIG. 3  is an enlarged, fragmentary left rear perspective view of the seed hopper of the seeder with ornamental panels removed; 
           [0008]      FIG. 4  is an enlarged, fragmentary left rear perspective view of the front end of the seed hopper showing the load cell that mounts the front end of the hopper on the center frame section of the machine; 
           [0009]      FIG. 5  is an enlarged, fragmentary left front perspective view of the seeder; 
           [0010]      FIG. 6  is a fragmentary top right perspective view of the seeder with the hopper removed to reveal details of construction; 
           [0011]      FIG. 7  is a fragmentary top plan view of the seeder with the hopper removed to reveal details of construction; 
           [0012]      FIG. 8  is a fragmentary left front perspective view of the seeder with the hopper removed to reveal details of construction; 
           [0013]      FIG. 9  is a fragmentary left rear perspective view of the seeder with the hopper removed to reveal details of construction; 
           [0014]      FIG. 10  is an enlarged, fragmentary, lower right front perspective view of the cultivator position sensors and the actuating structure therefor; 
           [0015]      FIG. 11  is a fragmentary, left top perspective view of the center section of the seeder with the hopper removed to reveal details of construction; 
           [0016]      FIG. 12  is a schematic diagram of the hydraulic operating circuit of the seeder; 
           [0017]      FIG. 13  is a diagram illustrating sequential operation of the cultivators and openers when the full sequence mode is selected by the operator; 
           [0018]      FIG. 14  is a diagram illustrating sequential operation of the cultivators and openers when the partial sequence mode is selected by the operator; and 
           [0019]      FIG. 15  is a schematic diagram of the electrical control circuit of the seeder. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    The present invention is susceptible of embodiment in many different forms. While the drawings illustrate, and the specification describes, certain specific embodiments of the invention, it is to be understood that such disclosure is by way of example only. The principles of the present invention are not limited to the particular disclosed embodiments. 
         [0021]    With initial reference to  FIGS. 1 and 2 , an exemplary cultivation air seeder in accordance with the present invention is broadly denoted by the numeral  10  and is provided with a mobile chassis or frame  12  having a tongue  14  and hitch structure  16  for connecting seeder  10  to a suitable towing tractor or other vehicle (not shown). A number of ground-engaging support and compaction wheels  18  are disposed across the rear of frame  12  to support the frame for over-the-ground travel and for compacting the soil after it has been cultivated by cultivation tools  20  (cultivators) on frame  12  ahead of wheels  18 . A row of furrow opening tools  22  (openers) of any suitable construction well known to those skilled in the art is supported across the rear of frame  12  behind wheels  18 . In the illustrated embodiment, seeder  10  comprises a three-section machine, such that frame  12  has a main frame section  24  and pair of left and right wing frame sections  25 ,  26  respectively, although the number of frame sections is not of importance insofar as the principles of the present invention are concerned. When applied to various parts of the machine, the terms “left” and “right” are utilized as if the machine were being viewed from the rear, looking forwardly. 
         [0022]    Seeder  10  further comprises a hopper  28  supported on main frame section  24  for holding a supply of seeds and/or fertilizer or other particulate materials to be distributed to openers  22 . Although the illustrated embodiment of the invention will be described in connection with the holding and distribution of seeds by hopper  28 , it will be appreciated that the principles of the present invention are not limited to seeds and may, in fact, be utilized in connection with many different kinds of particulate materials. 
         [0023]    A meter  30  ( FIG. 2 ) at the bottom of hopper  28  may be utilized to dispense seeds at a metered rate into one or more conduits  32  that transport the metered seeds within an airstream toward the rear of the machine. One or more distribution towers  34  are coupled with conduits  32  downstream from meter  30  for the purpose of dividing each primary stream of seeds into a multiplicity of secondary streams that flow to the openers  22  through hoses  35  (only a limited number being shown in the interest of clarity). Distribution towers  34  may advantageously take the form of the towers described and claimed in related application Ser. No. ______ titled “Seed Distribution Tower For An Air Seeder”, assigned to the assignee of the present invention. A blower  36  ( FIG. 2 ) adjacent the lower front end of hopper  28  supplies the transporting air for conduits  32  and secondary hoses  35 . 
         [0024]    Hopper  28  may be constructed in a variety of different shapes and sizes, and from a variety of different materials. In the illustrated embodiment, hopper  28  is constructed from sheet metal and is covered on three sides by an ornamental facing  29  of molded ABS plastic or the like, which is the subject of related application Ser. No. 13/157,856 titled “Cultivation Air Seeder With Visually Enhanced Seed Hopper”, assigned to the assignee of the present invention. 
         [0025]    Turning to  FIGS. 3-11 , the main or center frame section  24  is elongated in a fore-and-aft direction and is generally rectangular when viewed in plan. Fore-and-aft side beams  38 ,  40  are interconnected by a transverse beam  42  adjacent their fore-and-aft midpoint and are interconnected across their rear ends by a second transverse beam  44 . Center frame section  24  further includes a pair of left and right upright support plates  46 ,  48  respectively that are fixed to rear transverse beam  44  and fore-and-aft beams  38 ,  40 , substantially as rearwardly projecting extensions of beams  38 ,  40 . A third support plate  50  ( FIGS. 6-9 ) is also fixed to and projects rearwardly from rear transverse beam  44  midway between the plates  46 ,  48  in parallel relation therewith. 
         [0026]    The two support plates  46 ,  48  and the intermediate plate  50  cooperate to rotatably support two staggered, fixed axle wheels  18   a  and  18   b  of the group of wheels  18 . These two wheels  18   a,    18   b  are not raisable or lowerable relative to the rest of center frame section  24  and provide part of the ground support and soil compaction for the rear of center frame section  24 . Additional support and soil compaction for center frame section  24  is supplied by two pairs of staggered outboard wheels  18   c,    18   d  and  18   e,    18   f  that are vertically swingable relative to frame section  24  for causing the rear of frame section  24  to raise and lower. When outboard wheels  18   c,    18   d  and  18   e,    18   f  are lowered sufficiently by means yet-to-be-described, center frame section  24  and fixed wheels  18   a,    18   b  become raised into a transport position, with fixed wheels  18   a,    18   b  off the ground. 
         [0027]    A transverse torque tube  52  is rotatably supported behind wheels  18   a - 18   f  by the two upright support plates  46 ,  48 . Upstanding cranks  54 ,  56  are fixed to torque tube  52  adjacent support plates  46 ,  48  and are operably coupled at their upper ends to the rod ends of a pair of hydraulic cylinders  58 ,  60 . The base ends of cylinders  58 ,  60  are connected to support plates  46 ,  48 . For convenience, cylinders  58 ,  60  are hereinafter referred to as the “wheel cylinders.” 
         [0028]    Torque tube  52  is not operably coupled with fixed axle wheels  18   a,    18   b.  However, at opposite outboard ends of torque tube  52 , respective arched wheel arms  62 ,  64  are fixed thereto for rotation therewith when torque tube  52  is operated by wheel cylinders  58 ,  60 . Wheel arms  62 ,  64  project forwardly and downwardly to join at their lower forward ends with respective walking beam assemblies  66  ( FIG. 66 ) for each pair of raisable wheels  18   c,    18   d  and  18   e,    18   f.  Thus, the left pair of raisable wheels  18   c,    18   d  is connected via a walking beam assembly  66  to the lower front end of wheel arm  62 , while the right pair of raisable wheels  18   e,    18   f  is connected by its own walking beam assembly  66  to the lower front end of wheel arm  64 . Wheel pairs  18   c,    18   d  and  18   e,    18   f  are therefore raised and lowered relative to center frame section  24  by wheel cylinders  58 ,  60 . 
         [0029]    The center frame section  24  further includes a rear transverse beam  68  spaced below and slightly rearwardly of torque tube  52 . Beam  68  is fixed to the lower rear ends of upright support plates  46 ,  48  and to the rearmost end of intermediate support plate  50 . Two sets of lugs  70 ,  72  are fixed to beam  68  adjacent opposite ends thereof and project downwardly and slightly rearwardly therefrom to pivotally support a corresponding pair of rearwardly projecting links  74 ,  76 . Links  74 ,  76  are fixed joined at their rearmost ends to a transverse toolbar  78  that supports a center gang  22   a  of the openers  22 . A pair of hydraulic cylinders  80 ,  82  have their rod ends connected to links  74 ,  76  respectively and their base ends supported on upstanding structure fixed to transverse beam  68  for raising and lowering links  74 ,  76 . Thus, when cylinders  80 ,  82  are actuated, they raise or lower the center gang of openers  22   a  relative to center frame section  24 . For convenience, cylinders  80 ,  82  are hereinafter referred to as the “opener cylinders.” As will be seen, opener cylinders  80 ,  82  are also utilized to apply down pressure to openers  22   a.  An opener down position sensor  83  ( FIG. 11 ) in the nature of a proximity switch is mounted between one pair of the links  74 ,  76  and is covered and uncovered thereby for detecting when openers  22   a  are in their lowered position. 
         [0030]    Center frame section  24  supports a center section  20   a  of the cultivation tools  20  (cultivators). Separate tool sections  20   b  and  20   c  are supported by wing frame sections  25  and  26  respectively. Although the cultivators  20  may take a variety of different forms without departing from the principles of the present invention, in the illustrated embodiment the tools comprise front and rear rows of oppositely obliquely angled discs  84  and  86  ( FIG. 11 ), plus a row of leveling tines  88  behind rear discs  86 . The rear row of discs  86  is supported on a transverse rockshaft  90  that is in turn rotatably supported by appropriate bearing means (not shown) on the underside of fore-and-aft beams  38 ,  40  of center frame section  24 . Rockshaft  90  has a pair of upright lugs  92 ,  94  that are operably connected to the rod ends of a pair of corresponding hydraulic cylinders  96 ,  98  having their base ends attached to transverse beam  42  of center frame section  24 . Thus, extension and retraction of cylinders  96 ,  98  result in rotating rockshaft  90  in the appropriate direction to correspondingly raise and lower discs  86 . For convenience, cylinders  96 ,  98  are hereinafter referred to as the “cultivator cylinders” and may also be utilized to apply down pressure to the discs. 
         [0031]    Like rear disc row  86 , the discs  84  of the front row are mounted on a rockshaft  100  that is suitably rotatably mounted by bearing means (not shown) underneath fore-and-aft beams  38 ,  40  of center frame section  24 . Two sets of fore-and-aft links  102 ,  104  operably interconnect rockshafts  90  and  100  so as to transfer the rotary motion of rockshaft  90  to rockshaft  100 . Thus, actuation of cultivator cylinders  96 ,  98  results in simultaneous actuation of both sets of discs  84 ,  86 . In a similar manner, the leveling tines  88  are mounted on their own rockshaft  106  that is bearing-supported for rotation about its longitudinal axis by suitable bearing means (not shown) beneath fore-and-aft beams  38 ,  40 . A pair of hydraulic cylinders  108 ,  110  serve as motion-transmitting links between the rockshaft  96  of rear discs  86  and rockshaft  106  of tines  88  so that all the discs  84 ,  86  and leveling tines  88  of center frame section  24  raise and lower in unison. If need be, the position of tines  98  relative to discs  84 ,  86  can be adjusted somewhat by appropriately extending or retracting cylinders  108 ,  110 . Otherwise, cylinders  108 ,  110  are not extended or retracted and serve only to operably couple the tines with the discs for conjoint operation thereof. A pair of cultivator position sensors  112 ,  114  ( FIG. 10 ) are mounted on right fore-and-aft beam  40  of main frame section  24  for the purpose of detecting when cultivators  22  are in their raised position and their lowered position. Sensor  112  is the raised position sensor, while sensor  114  is the lowered position sensor, both of which are actuated by an elongated link  115  connected to motion-transmitting link  104 . 
         [0032]    Hopper  28  is supported on center frame section  24  in such a manner that the weight of hopper  28 , and more particularly, the weight of its contents, can be continuously monitored and that information used to perform one or more control functions of the seeder. In this respect it will be noted that hopper  28  has a pair of downwardly and slightly rearwardly projecting, rigid legs  116  and  118  ( FIG. 3 ) at opposite rear corners thereof. Each leg  116 ,  118  is mounted on and supported by the weigh bar of a corresponding transversely extending load cell  120 ,  122  that is in turn fixedly mounted on the corresponding upstanding support plate  46  or  48 . At its front end hopper  28  is mounted on and supported by the weigh bar of a single, fore-and-aft extending load cell  124  ( FIG. 4 ) that is fixedly connected at its rear end to a centrally located bracket assembly  126  of the hopper and at its front end to an upstanding, upwardly arched and transversely extending support member  128  that straddles beams  38 ,  40  of center frame section  24 . Thus, hopper  28  is supported at three points by three load cells  120 ,  122 , and  124  of the type that are well known to those skilled in the art. Satisfactory load cells of this type may be obtained from and programmed by a variety of suppliers such as, for example, Digi-Star LLC of Fort Atkinson, Wis. 
         [0033]    The two wing sections  25  and  26  are substantially similar to one another in construction and operation, in some respects being mirror images of one another. Each wing section  25 ,  26  is somewhat generally L-shaped in plan, having a front, larger rectangular portion defined in part by four transverse beams  130 ,  132 ,  134 ,  136  and three fore-and-aft beams  138 ,  140 ,  142 , and smaller, wheel-supporting rear rectangular portion defined in part by fore-and-aft, laterally spaced apart beams  144 ,  146 ,  148 , and  150 . Fore-and-aft beams  144 - 150  are fixed at their front ends to the outboard half of transverse beam  136 , and at their rear ends to a shorter transverse beam  152  that is slightly more than one-half the length of beam  136 . Three fixed axle wheels  18   g,    18   h,  and  18   i  are supported in a staggered pattern by and between fore-and-aft beams  144 - 150  on left wing frame section  25 , while a corresponding set of three fixed axle wheels  18   j,    18   k,  and  18   l  are supported in a similar manner on right wing frame section  26 . Although the inboard end of transverse beam  136  of each wing frame section  25 ,  26  passes in front of a corresponding pair of wheels  18   c,    18   d  or  18   e,    18   f,  such wheels  18   c,    18   d  and  18   e,    18   f  are not supported by or connected to beam  136 . As explained above, such wheels  18   c,    18   d  and  18   e,    18   f  are vertically swingably mounted on the center frame section  24 . 
         [0034]    Each of the wing frame sections  25 ,  26  is rendered vertically swingable between a lowered operating position and a raised folded position by virtue of a pair of aligned, fore-and-aft pivots  154  and  156  ( FIG. 8 ) connecting the inboard ends of beams  130  and  134 , respectively, to fore-and-aft beams  38  or  40  of center frame section  24 . Wheels  18   g,    18   h  and  18   i  thus move up and down with wing frame section  25  during its raising and lowering, while wheels  18   j,    18   k  and  18   l  move up and down with wing frame section  26  during its raising and lowering operations. 
         [0035]    Raising and lowering of wing frame sections  25  and  26  is carried out by a pair of large, transversely extending hydraulic cylinders  158  and  160 . Front cylinder  158  has its rod end pivotally coupled with an upstanding lug assembly  162  on the inner end of front beam  130  of left wing frame section  25  and its base end pivotally connected to an upstanding lug assembly  164  on the inner end of front beam  130  of right wing frame section  26 . The rear cylinder  160  is inverted end-for-end from front cylinder  158  and has its base end pivotally connected to an upstanding lug assembly  166  on the inner end of beam  136  of left wing frame section  25  and its rod end pivotally connected to an upstanding lug assembly  168  on the inner end of beam  136  of right wing frame section  26 . It will thus be seen that both of the cylinders  158 ,  160  are connected only to and between the wing frame sections  25 ,  26 , and not to the center frame section  24 . For convenience, cylinders  158 ,  160  will hereinafter be referred to as the “wing cylinders.” As will be seen, in addition to providing a means of folding and unfolding wing frame sections  25 ,  26 , wing cylinders  158 ,  160  can also be utilized to apply down pressure to the compaction wheels of wing frame sections  25 ,  26  in adjustable amounts. 
         [0036]    Each of the wing frame sections  25 ,  26  carries cultivation tools of the same design and in the same manner as center frame section  24 . Therefore, a detailed description of the tools on wing frame sections  25 ,  26  and their mounting arrangements is not necessary. Suffice it to point out that the discs  84 ,  86  and tines  88  of each wing frame section  25 ,  26  are raised and lowered in unison by a pair of cultivation cylinders  170 ,  172  in the same manner as cultivation cylinders  96 ,  98  on the center frame section  24 . All of the cultivation cylinders  96 ,  98 ,  170 ,  172  are plumbed in parallel so that all of the cultivation tools  20  across the entire machine are raised or lowered in unison. 
         [0037]    Each of the wing frame sections  25 ,  26  carries a gang of openers, the openers associated with the left wing frame section  25  being denoted by the numeral  22   b  and the openers associated with the right wing frame section  26  being denoted by the numeral  26   c.  Openers  22   b  and  22   c  are mounted on their respective wing frame sections  25  and  26  in substantially the same manner as the openers  22   a  on center frame section  24 . Suffice it to point out, therefore, that each gang of openers  22   b  and  22   c  is raised and lowered by its own opener cylinder  174 . All the opener cylinders  80 ,  82 ,  174  are plumbed in parallel for raising and lowering all the openers across the entire machine in unison. 
         [0038]    The wheel cylinders  58 ,  60 ; opener cylinders  80 ,  82  and  174 ; cultivator cylinders  96 ,  98 , and  170 ,  172 ; and wing cylinders  158 ,  160  all comprise part of what will hereinafter be referred to as a hydraulic operating circuit  176  of the machine. Operating circuit  176  also includes a number of electrically controlled valves and other components as illustrated in  FIG. 12  for controlling fluid flow to and from such cylinders. 
         [0039]    Referring to  FIG. 12 , operating circuit  176  is adapted to cooperate with a three-position valve  178  on the tractor (not shown) that is biased to a neutral position but may be manually shifted by the operator to either of two other selectable positions. The tractor also has a pump  180  and a tank  182  connected to valve  178 . 
         [0040]    Operating circuit  176  includes a main line  184  leading from tractor valve  178  and connected in parallel flow relationship with a plurality of branch lines  186 ,  188 ,  190 , and  192 . Branch lines  186 ,  188  and  190  respectively lead to the base ends of wheel cylinders  58 ,  60 ; opener cylinders  80 ,  82 ,  174 ; and cultivator cylinders  96 ,  98 ,  170 ,  172 , while branch line  192  leads to the rod end of wing cylinders  158 ,  160 . Wheel branch line  186  has a first normally closed, electrically actuable wheel solenoid valve  194 , as well as a manually adjustable variable orifice  196  that is located between wheel valve  194  and main line  184 ; opener branch line  188  has a first normally closed, electrically actuable opener solenoid valve  198 , as well as a manually adjustable variable orifice  200  that is located between opener valve  198  and main line  184 ; cultivator branch line  190  has a first normally closed, electrically actuable cultivator solenoid valve  202 , as well as a manually adjustable variable orifice  204  that is located between cultivator valve  202  and main line  184 ; and wing branch  192  has a first normally closed, electrically actuable wing solenoid valve  206 , as well as a manually adjustable variable orifice  208  that is located between wing valve  206  and main line  184 . 
         [0041]    Operating circuit  176  further includes a main line  210  leading from tractor valve  178  and connected in parallel flow relationship with a plurality of branch lines  212 ,  214 ,  216 , and  218 . Branch lines  212 ,  214 , and  216  respectively connect with the rod ends of wheel cylinders  58 ,  60 ; opener cylinders  80 ,  82 ,  174 ; and cultivator cylinders  96 ,  98 ,  170 ,  172 , while branch line  218  connects with the base ends of wing cylinders  158 ,  160 . Wheel branch line  212  has a second normally closed, electrically actuable wheel solenoid valve  220 , as well as a second manually adjustable variable orifice  222  that is located between wheel valve  220  and main line  210 ; opener branch line  214  has a second normally closed, electrically actuable opener solenoid valve  224 , as well as a manually adjustable variable orifice  226  that is located between opener valve  224  and main line  210 ; cultivator branch line  216  has a second normally closed, electrically actuable cultivator solenoid valve  228 , as well as a manually adjustable variable orifice  230  that is located between cultivator valve  228  and main line  210 ; and wing branch line  218  has a second normally closed, electrically actuable wing solenoid valve  232 , as well as a manually adjustable variable orifice  234  that is located between wing valve  232  and main line  210 . 
         [0042]    Operating circuit  176  further includes a blower motor circuit comprising a main line  236  and a main line  238  that are controlled by a second tractor valve  240  connected to pump  180  and the tank  182 . The blower  36  of the seeder is driven by a rotary hydraulic motor  36   a  that is connected to main line  236  by a blower branch line  242  and to main line  238  by a blower branch line  244 . Main line  238  connects to wing branch line  192 , and a pilot-operated check valve  246  in main line  238  prevents flow from wing branch line  192  through main line  238  when wing valve  206  is open for pressurizing the rod ends of wing cylinders  158 ,  160 . Normally closed check valve  246  is openable by pressure in main line  236  via a pilot line  248 . 
         [0043]    Operating circuit  176  additionally includes an electro-proportional, three-position pressure reducing valve  250  connected to main line  236  of the blower motor circuit via a line  252  and to main line  238  of the blower motor circuit via a line  254 . Pressure reducing valve  250  is also connected to wing branch line  218  via a line  256 . Pressure reducing valve  250  is biased to the position illustrated in  FIG. 12 , which is a constant reduced pressure position wherein branch line  252  is communicated with line  256 , while no communication is established for line  254 . When pressure reducing valve  250  is shifted to an intermediate position part way down from the position in  FIG. 12 , lines  252  and  254  are communicated with line  256  via restricted passages in pressure reducing valve  250 . In a fully shifted position all the way down from the illustrated position in  FIG. 12 , only line  254  is communicated with line  256  for full relief to tank  182 , while line  252  is closed. A pilot line  258  is connected between line  256  and the “upper” end of pressure reducing valve  250  viewing  FIG. 12 , and a second pilot line  260  is connected between line  254  and the “bottom” end of pressure reducing valve  250  viewing  FIG. 12 . One suitable such pressure reducing valve  250  is available from Sun Hydraulics Corporation of Lenexa, Kans. as model PRDM-XBN electro-proportional, direct-acting, pressure reducing/relieving valve with open transition-high pressure setting with no command. 
         [0044]    Operating circuit  176  also includes an arrangement for applying down pressure to the openers  22  during field operations utilizing the blower motor circuit. In this respect, a line  262  connects line  252  with opener branch line  188  at a point between opener valve  198  and the base ends of opener cylinders  80 ,  82 ,  174 . Another line  264  connects line  254  with opener branch line  214  at a point between second opener valve  224  and the rods ends of opener cylinders  80 ,  82 ,  174 . A manually settable pressure reducing valve  266  and a normally closed, electrically actuable solenoid valve  268  are connected in series flow relationship within line  262 , with the electrically actuable valve  268  being located between pressure reducing valve  266  and the rod ends of opener cylinders  80 ,  82 ,  174 . A single normally closed, electrically actuable valve  270  is located within line  264 . 
         [0045]    The seeder also has an electrical control circuit illustrated in  FIG. 15  and broadly denoted by the numeral  272  for controlling operation of the hydraulic operating circuit  176 . Many of the components of control circuit  272  have previously been described, such as, for example, the cultivator up sensor  112 , the cultivator down sensor  114 , load cells  120 ,  122 ,  124 , and the opener down sensor  83 . A number of additional components are also included, primary among which is a programmable controller  274  that serves as the “brains” of the control circuit. One suitable such properly programmed controller  274  is available from Mueller Electronics, Inc. of Burr Ridge, Ill. as the DRILL MANAGER ME. 
         [0046]    Controller  274  is connected via a CAN bus or ISO bus to a tractor-mounted monitor  276  having a start switch  277 , as well as a number of other switches and informational icons. When connected to the programmed controller  274 , monitor  276  provides a number of selectable, touch-screen or mechanical mode switches which may be used to toggle between modes and perform other functions after the system is started up in the initial mode by depressing start switch  277 . Such selectable mode switches include at least a transport mode switch  278 , a fold mode switch  280 , and either or both of a cultivator full sequence mode switch  282  and a cultivator partial sequence mode switch  284 . Inputs into controller  274  are made by the cultivator up sensor  112 , the cultivator down sensor  114 , load cells  120 ,  122 ,  124 , the opener down sensor  83 , and a pressure feedback transducer  286  connected to wing cylinder branch line  218  from the base end of wing cylinders  158 ,  160  as also shown on the operating circuit schematic in  FIG. 12 . Depending on the particular mode selected by the operator at the time, outputs are made by controller  274  to wing cylinder valves  218  and  232  to actuate those valves simultaneously, to wheel cylinder valves  194  and  220  to actuate those valves simultaneously, to opener cylinder valves  198  and  224  to actuate those valves simultaneously, to cultivator cylinders valves  202  and  228  to actuate those valves simultaneously, to proportional pressure reducing valve  250 , and to opener down pressure valves  268 ,  270  to actuate those valves simultaneously. Controller  274  also activates and deactivates an electric motor  30   a  that drives seed meter  30 . 
       Sequencing Operations  
       [0047]    Upon startup by actuating start switch  277 , the display on monitor  276  is activated. In this initial mode, none of the valves are powered and no functions are active. The system is then transitioned from the initial mode to the proper state of operation by the operator choosing which function he wishes to engage in and depressing the appropriate mode switch (transport switch  278 , fold switch  280 , cultivator full sequence switch  282 , or cultivator partial sequence switch  284 ). 
         [0048]    The fold mode is applicable when entering or exiting a field and is used for folding or unfolding the wings of the seeder. When the fold mode is selected by depressing fold switch  280 , both wing valves  206  and  232  are simultaneously activated to an open condition by controller  274  to energize the fold circuit. No other hydraulic function is available in the fold mode. Assuming the wings are initially in a folded condition with wing cylinders  158 ,  160  contracted, when the operator then manually shifts (pulls) tractor valve  178  to the left as viewed in  FIG. 13 , the rod ends of wing cylinders  158 ,  160  are communicated with tank  182  via branch line  192 , open valve  206  and main line  184 , while the base ends are communicated with pump  180  via branch line  218 , open valve  232  and main line  210 . Cylinders  158 ,  160  therefore gradually extend to lower the wings to the ground. To raise the wings, the operator shifts (pushes) tractor valve  178  in the opposite direction to communicate the rod ends of wing cylinders  158 ,  160  with pump  180  via branch line  192 , open valve  206  and main line  184 , while the base ends are communicated with tank  182  via branch line  218 , open valve  232  and main line  210 . Cylinders  158 ,  160  therefore gradually retract to raise the wings to their folded condition. When the operator returns tractor valve  178  to the neutral position of  FIG. 13 , fluid flow ceases. 
         [0049]    The transport mode is applicable when preparing the seeder for or exiting from over-the-road travel. When transport mode switch  278  is depressed, both wheel valves  194  and  220  are simultaneously activated to an open condition by controller  274  to activate the wheel lift/lower circuit. No other hydraulic function is available in the transport mode. Assuming the wings have already been folded and the operator wishes to raise the center section  24  for over-the-road travel, after depressing the transport mode switch  278  the operator then manually shifts (pulls) tractor valve  178  to the left viewing  FIG. 13  to communicate the pump  180  with the rod ends of wheel cylinders  58 ,  60 , via main line  210 , open valve  220  and branch line  212 , while their base ends are communicated with tank  182  via branch line  186 , open valve  194  and main line  184 . Cylinders  58 ,  60  therefore gradually contract to lower wheels  18   c,    18   d,    18   e,    18   f  relative to center section  24  and raise center section  24  relative to the ground. Once the fixed axle wheels  18   a,    18   b  have been lifted off the ground with the raised center section  24 , the operator may return tractor valve  178  to its neutral position of  FIG. 13  and the machine is ready for over-the-road travel, carried by wheels  18   c - 18   f.  To lower the machine back down to a field operating height, after depressing the transport mode switch  278 , the operator shifts (pushes) tractor valve  178  to the right viewing  FIG. 13  to communicate the rod ends of wheel cylinders  58 ,  60  with tank  182  via branch line  212 , open valve  220  and main line  210 , while the base ends are communicated with pump  180  via main line  184 , open valve  194  and branch line  186 . Cylinders  58 ,  60  gradually extend to allow wheels  18   c - 18   f  to rise relative to center section  24  and thereby lower center section  24  back down toward the ground. When the operator returns tractor valve  178  to the neutral position of  FIG. 13 , fluid flow ceases. 
         [0050]    The operating and control system of the present invention (operating circuit  176  and control circuit  272 ) is designed for sequenced raising or lowering of the cultivators  20  and openers  22  during turns in the headland area of a field or the like. In the disclosed embodiment, the operator may select either a full sequence mode, wherein the cultivators  20  and openers  22  are sequenced during both raising and lowering, or a partial sequence mode wherein the cultivators  20  and openers  22  lower simultaneously but raise in sequence. It is within the principles of the present invention to have only one of such modes, however. Once the desired mode as been selected by depressing either the full sequence switch  282  or the partial sequence switch  284 , the controller  274  takes over to prepare operating circuit  176  for carrying out the chosen function when the operator shifts tractor valve  178 . 
         [0051]    In either mode, when controller  274  activates the opener circuit, both opener valves  198 ,  224  are opened simultaneously. Likewise, when controller  274  activates the cultivator circuit, both cultivator valves  202 ,  228  are opened simultaneously. Thus, when the operator shifts (pushes) tractor valve  178  to the right viewing  FIG. 12  and the controller has opened opener valves  198 ,  224 , the openers  22  lower as the base ends of opener cylinders  80 ,  82 ,  174  communicate with pump  180  via main line  184 , open valve  198  and branch line  184 , while the rod ends communicate with tank  182  via branch line  214 , open valve  224  and main line  210 . Once the opener down position sensor  83  senses openers  22  are fully lowered, it signals the controller  174  which closes opener valves  198 ,  224  and stops further extension of opener cylinders  80 ,  82 ,  174 . When the operator shifts (pulls) tractor valve  178  to the left viewing  FIG. 12  to raise openers  22 , if controller  274  has opened opener valves  198 ,  224  the openers  22  are raised as the rod ends of opener cylinders  80 ,  82 ,  174  communicate with pump  180  via main line  210 , open valve  224  and branch line  214 , while the base ends communicate with tank  182  via branch line  188 , open valve  198  and main line  184 . 
         [0052]    Similarly, during such shifting (pushing) of tractor valve  178  to the right, if controller  274  has opened cultivator valves  202 ,  228 , the cultivators  20  lower as the base ends of cultivator cylinders  96 ,  98 ,  170 ,  172  communicate with pump  180  via main line  184 , open valve  202  and branch line  184 , while the rod ends of cultivator cylinders  96 ,  98 ,  170 ,  172  communicate with tank  182  via branch line  216 , open valve  228  and main line  210 . When cultivator down sensor  114  senses cultivators  20  are fully lowered, it signals the controller  274  which closes cultivator valves  202 ,  228  and stops further extension of cultivator cylinders  96 ,  98 ,  170 ,  172 . During shifting (pulling) of tractor valve  178  to the left for raising cultivators  20 , if controller  274  has opened cultivator valves  202 ,  228 , the cultivators are raised as the rod ends of cultivator cylinders  96 ,  98 ,  170 ,  172  communicate with pump  180  via open valve  228  and main line  210 , while the base ends of cultivator cylinders  96 ,  98 ,  170 ,  172  communicate with tank  182  via open valve  202  and main line  184 . When cultivator up sensor  112  senses cultivators  20  are fully raised, it signals the controller  274 . 
         [0053]    The sequential operation of cultivators  20  and openers  22  in the full and partial sequence modes is illustrated in the diagrams of  FIGS. 13 and 14 . In both diagrams, the heavy solid line  288  represents cultivator position as a function of time, while the heavy solid line  290  represents opener position as a function of time. In both diagrams, broken line  292  represents the condition of the cultivator valves  202 ,  228  as a function of time, while broken line  294  represents the condition of opener valves  198 ,  224  as a function of time. In both diagrams, broken line  296  represents the condition of the opener down pressure valves  268 ,  270  as a function of time. 
         [0054]    If the operator has selected the full sequence mode of  FIG. 13  by depressing full sequence switch  282 , when tractor valve  178  is shifted to the lowering position for lowering cultivators  20  and openers  22 , the controller  274  causes cultivators  20  to be lowered first. When lower cultivation position sensor  114  detects that cultivators  20  have been fully lowered, it signals controller  274 , which closes cultivator valves  202 ,  228  to stop lowering cultivators  20 , opens opener valves  198 ,  224  to start lowering openers  22 , and activates meter motor  30   a  to start dispensing seeds from hopper  28 . When lower opener position switch  83  detects that openers  22  have been fully lowered, it signals controller  274 , which recloses opener valves  198 ,  224 . Opener valves  198 ,  224  remain closed until a later raising sequence. Cultivator valves  202 ,  228  are reopened by controller  274  after a predetermined time delay measured from their closing point and remain open until the next time the cultivators have been raised. The meter motor  30   a  remains activated until the cultivators  20  leave their fully lowered position during a raising sequence. 
         [0055]    When the operator wants to raise cultivators  20  and openers  22  from their lowered positions when in the full sequence mode, he shifts tractor valve  178  to the raising position. Cultivator valves  202 ,  228  are still open at this point, so cultivators  20  immediately begin to lift and continue such movement until the cultivator up position sensor  112  detects their arrival at the fully raised position. Meter motor  30   a  shuts off as cultivators  20  start to rise. Upon arrival of the cultivators  20  at their raised position, the cultivator up position sensor  112  signals the controller  274 , which closes cultivator valves  202 ,  228  for a predetermined period of time and (after a short delay) activates opener valves  198 ,  224 . Openers  20  rise from their lowered positions until opener cylinders  80 ,  82 ,  174  reach their stroke limit. When the time delay elapses for the closed cultivator valves  202 ,  228 , controller  274  reopens cultivator valves  202 ,  228  and recloses opener valves  202 ,  228 . If the operator continues to hold tractor valve  178  in the raising position after cultivator valves  202 ,  228  are reopened, the cultivators  20  can rise somewhat further until the stroke limit of cultivator cylinders  96 ,  98 ,  170 ,  172  is reached. 
         [0056]    It will thus be seen that in the full sequence mode, the operator can avoid seeding problems previously experienced during headland turns and the like when cultivators and openers were both raised simultaneously and lowered simultaneously. In the full sequence mode, as the farmer approaches the headland and wants to raise the cultivators  20  and openers  22  for the turn around, he shifts the tractor valve  178  to the raising position, causing the cultivators to immediately lift from the ground and stop cultivating. Meter  30  shuts off as well, but the blower  36  keeps sending seeds that remain in the system to the openers  22 , which stay down at this time and keep depositing the left-over seeds into the ground as the seeder continues to advance. Shortly after the cultivators  20  reach their raised position, the openers  22  start to rise to terminate seeding operations and then remain raised with the cultivators  20  while the operator completes his turn around. By sequencing raising of the cultivators  20  and openers  22  in this way, the openers  22  are not raised prematurely to skip an area near the headland that should be seeded, or, alternatively, the cultivators  20  are not be left down so long as to cultivate areas of the headland that should not be cultivated at this time. 
         [0057]    After getting properly positioned for the next pass, the operator starts down the rows and shifts tractor valve  178  to the lowering position. Cultivators  20  immediately lower into their ground working positions to start their cultivation function, but openers  22  remain raised and meter motor  30   a  remains off until the cultivators  20  reach their lowered position. Once the cultivators are in their lowered position, the meter motor  30   a  is activated and openers  22  commence their lowering movement. Thus, no seeds are deposited until the rear of the seeder has moved out of the headland and into the newly cultivated soil of the next pass. 
         [0058]    The partial sequence mode of  FIG. 14  produces an outcome similar to that of the full sequence mode with respect to raising, but not lowering. In the partial sequence mode the cultivators  20  and the openers  22  are raised in sequence, with the cultivators  20  raising first, but they are lowered simultaneously. Thus, as illustrated in the partial sequence mode diagram of  FIG. 14 , if the operator has depressed partial sequence switch  284 , when tractor valve  178  is shifted to the lowering position the controller  274  causes opener valves  198 ,  224  to open (cultivator valves  202 ,  228  are already open), and both the cultivators  20  and openers  22  lower simultaneously. When lower cultivation position sensor  114  detects that cultivators  20  are fully lowered, controller  274  closes cultivator valves  202 ,  228  for a predetermined time delay and meter motor  30   a  is activated. When opener down position sensor  83  detects that openers  22  are in their lowered position, controller  274  closes opener valves  198 ,  224  and keeps them closed until the next opener raising cycle. Cultivator valves  202 ,  228  are reopened by controller  274  after the expiration of the time delay, and they remain open throughout the next raising sequence and until the next lowering operation. The meter motor  30   a  remains activated until cultivators  20  leave their lowered position during the next raising sequence. 
         [0059]    When the operator wants to raise cultivators  20  and openers  22  from their lowered positions when in the partial sequence mode, he shifts tractor valve  178  to the raising position. Cultivation valves  202 ,  228  are in an open condition at this time, so cultivators  20  immediately begin to lift until the cultivator up position sensor  112  detects their arrival at the raised position. Meter motor  30   a  shuts off as cultivators  20  start to rise. Upon arrival of cultivators  20  at their raised position, the cultivator up position sensor  112  signals the controller  274 , which, after a short delay, activates opener valves  198 ,  224  to cause openers  22  to rise until opener cylinders  80 ,  82 ,  174  reach their stroke limits. Opener valves  198 ,  224  remain open, along with cultivator valves  202 ,  228 , until the completion of the next lowering cycle. 
         [0060]    It will thus be seen that in the partial sequence mode, the operator can still achieve the benefits of delayed raising of the openers as he approaches the headland and prepares for a turn. Even though the cultivators  20  are lifting and the meter motor  30   a  has been deactivated, seeds in the system continue to be delivered to the openers  22 , and the openers continue to deposit them in the soil, until the cultivators have been raised. Once the operator has completed his turn around and is ready to start back down the rows in the next pass, the cultivators  20  and the openers  22  are lowered simultaneously when he shifts the tractor valve to the lowering position, and the meter motor  30   a  is reactivated when the cultivators reach their lowered positions. 
       Opener Down Pressure  
       [0061]    It is desirable to apply hydraulic down pressure to the openers  22  when they are in their lowered positions engaging the ground. This is accomplished by utilizing pressure (with little flow) from the blower motor circuit (controlled by second tractor valve  240 ) as long as the pressure in that circuit is high enough to continue to support operation of blower motor  36   a.  The components of operating circuit  176  for carrying out the application of down pressure to opener cylinders  80 ,  82 ,  174  are the manually settable pressure reducing valve  266  and solenoid valves  268 ,  270  (controlled by controller  274 ). 
         [0062]    The operator manually adjusts valve  266  so that it does not allow pressure seen by the base ends of opener cylinders  80 ,  82 ,  174  to exceed a selected level, thereby maintaining sufficient pressure in the blower motor circuit to satisfactorily operate blower motor  36   a.  If valves  268 ,  270  are open (by controller  274 ), pressure from blower motor main line  236  communicates with the base ends of opener cylinders  80 ,  82 ,  174  in an effort to extend the cylinders, thus pushing openers  22  against the ground. The ground, of course, resists such extension and, therefore, there is little flow but sufficient pressure to keep the openers  22  fully pressed down into the soil. The opened valve  270  communicates the rod ends of opener cylinders  80 ,  82 ,  174  with tank  182  via lines  214 ,  264 ,  254 , and main line  238 . When valves  268 ,  270  are closed (by controller  274 ), valve  266  remains open, but there can be no communication of blower motor main line  236  with opener cylinders  80 ,  82 ,  174 . 
         [0063]    Controller  274  is programmed to only open valves  268 ,  270  in the full sequence mode or the partial sequence mode, and then only when the openers  22  are in their lowered positions. As illustrated in the full sequence mode diagram of  FIG. 13 , for example, down pressure valves  268 ,  270  are off (closed) unless cultivators  20  and openers  22  are in their lowered positions. Once openers  22  are in their lowered position, the opener down position sensor  83  signals such condition to controller  274  and, following a short time delay, controller  274  causes down pressure valves  268 ,  270  to turn on (open). Down pressure valves  268 ,  270  remain on (open) until the next time cultivators  20  are raised to their raised position, at which time the cultivator up position sensor  112  signals controller  274  that cultivators  20  are raised. Controller  274  immediately turns off (closes) down pressure valves  268 ,  270 , and after a short time delay the controller  274  causes the openers  22  to commence their raising movement. Opener down pressure valves  268 ,  270  remain off (closed) until completion of the next lowering cycle of the openers  22 . Similarly, in the partial sequence mode, the opener down pressure valves  268 ,  270  only come on (open) following a short time delay after the opener down position sensor  83  signals controller  274  that the openers  22  have reached their lowered position. The opener down pressure valves  268 ,  270  then turn off (close) when cultivator up position sensor  112  signals controller  274  that cultivators  20  are raised in their raised position. 
       Hopper Weighing to Perform Control Functions 
       [0064]    The weight of hopper  28  throughout field operation is deter mined by load cells  120 ,  122 ,  124  in conjunction with controller  274  and may be used to perform various control functions on the seeder. For example, in addition to a direct display to the operator of the weight at any point in time, and the activation of alarms when the hopper is full or becomes empty, the decreasing weight read by the load cells as the volume of seeds reduces in the hopper can be used to calculate the actual amount of product applied over a given area, which is then compared with the intended amount. If a deviation between the two values is greater than a set point, an error message can be displayed on the monitor  276 . Another use of the weight information is to calculate and display the estimated time of depletion, based upon the rate of depletion determined by comparing the weight at known time intervals. A further control function performed using hopper weight information is adjusting (reducing) the down pressure applied to the ground wheels of the wing sections as the hopper lightens so as to keep the compaction pressure applied by the wing section wheels to the cultivated soil substantially the same as that applied by the center section wheels throughout field operations. Without such adjustment, the compaction pressure applied by the center section wheels would decrease as the hopper lightens due to seed depletion, while the compaction pressure applied by the wing section wheels would remain substantially unchanged. This could result in unequal planting depths, uneven seed emergence and other undesirable outcomes. 
         [0065]    In the illustrated embodiment, the controller  274  is programmed such that wing wheel down pressure can only be adjusted during the full sequence mode or the partial sequence mode, i.e., when neither the transport mode nor the fold mode is selected. With reference to  FIG. 12 , when the wing cylinders  158 ,  160  are in their extended positions with the wing wheels  18   g,    18   h,    18   i  and  18   j,    18   k,    18   l  engaging the ground, wing valves  206 ,  232  are closed. Instantaneous weight information from load cells  120 ,  122 ,  124  is continuously signaled to controller  274 , as is instantaneous pressure information from the pressure transducer  286  that is in continuous communication with the base end of wing cylinders  158 ,  160 . If controller  274  determines at any time during such continuous measurement that the value for the detected net weight of hopper  28  results in a sufficient disparity with the value for the wing down pressure at the base ends of wing cylinders  158 ,  160 , controller  274  causes pressure reducing valve  250  to shift a proportional amount and allow the base ends of wing cylinders  158 ,  160  a degree of communication with tank  182  via lines  218 ,  256 ,  254 , and  238 . Passage through the proportionally shifted valve  250  is restricted by the restricted orifices within such valve. This results in a small pressure reduction at the base ends of wing cylinders  158 ,  160  and enables the upwardly directed ground forces to cause a corresponding small retraction of wing cylinders  158 ,  160 . Such retraction of wing cylinders  158 ,  160  results in a small amount of fluid being drawn into the rod ends of cylinders  158 ,  160  from the blower motor circuit via lines  192  and  238 . Controller  274  permits such drawing of fluid from the blower motor circuit only if the blower function would not be compromised, i.e., only if the motor speed exceeds a predetermined level such as, for example, 1000 rpm. In the event that a larger disparity in the weight value and the pressure value is determined by controller  274 , controller  274  causes proportional valve  250  to shift to its full relief position wherein the internal restricted orifices of valve  250  are bypassed and line  256  is connected directly with line  254  and main line  238  of the blower motor circuit to the tank  182 . 
         [0066]    It has been found that the following equation satisfactorily controls the pressure reduction function but is dependent in part upon the size and weight of the seeder  10 : 
         [0000]        P =( W/K 1)+ K 2       Where:   P=pressure needed (psi), W=net weight measured (lbs), and K1 and K2 are constants.
 
In a seeder that is six meters in overall width, satisfactory results have been achieved where K1=14 and K2=115. The values for K1 and K2 change, depending upon the size and weight of the seeder.
         
         [0069]    The controller  274  and/or functions thereof may be embodied in software, in hardware, or in a combination thereof. In various embodiments, the controller  274  and/or functions thereof may be embodied as computer readable codes on a computer readable recording medium to perform tasks such as processing and calculation operations, such as processing the weight and down pressure data and calculating an appropriate response. The computer readable recording medium may include any data storage device suitable to store data that can be read by a computer system. A non-exhaustive list of possible examples of computer readable recording mediums include read-only memory (ROM), random-access memory (RAM), CD-ROMS, magnetic tapes, floppy disks, optical storage devices, and carrier waves such as data transmission via the interne. The computer readable recording medium may also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distribution fashion. 
         [0070]    The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as it pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.