Abstract:
A hydraulic control apparatus for a foldable farm includes first hydraulic control system is used to control weight transfer to ground engaging tools mounted to a stationary and foldable wing frame sections. A second hydraulic system is used to fold and unfold the wing sections. A hydraulic control is provided that interfaces with both hydraulic systems to control sequencing of the functions provided by the first and second hydraulic systems. The first and second hydraulic systems have electronically controlled valves to control the flow of hydraulic fluid to various lifting, folding, and down pressure cylinders.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to farm implements and, more particularly, a hydraulic control system having a single remote hydraulic control. 
     Modern farmers strive to improve the management of the increasing amounts of farm acres. Improving management requires farmers to be able to quickly prepare the soil and plant seed each season. This haste has driven the need for more efficient and larger agricultural machinery. 
     Implements such as harrows, packers, or combined harrow-packers are being made with widths exceeding sixty feet in the field operating position. Also, drill implements employed to distribute seed product across an agricultural field are also being made increasingly wider in the field operating position. Wider working widths provide more efficient field working such as by increasing the number of rows that are seeded in a single pass or by increasing the amount of field that is tilled in a single pass. However, as agricultural implements have been made increasingly wider, there has been a need for systems to compactly fold the implement for practical and safe transport over highways and through gates, and for greater maneuverability. These systems typically consist of hydraulic cylinders and valves that are controlled by a remote operator control to fold and unfold the implement. 
     Moreover, with agricultural implements, such as hoe drills, requiring fluid power (hydraulic) circuits to perform an increasing number of other tasks, a greater number of control interfaces are similarly required. The increased number of control interfaces adds to the complexity of the overall hydraulic system and reduces space within the operator cab of the towing vehicle for the implement for other implement controls. A narrow transport hoe drill, for example, will be capable of performing several hydraulically powered functions, such as raising and lowering the ground engaging tools, e.g., openers, applying a trip force on the ground engaging tools, and setting the amount of packing pressure that is applied by the packer wheels. Additionally, as noted above, the wing sections of the hoe drill, which are mounted to opposite lateral sides of a stationary frame section, are hydraulically folded to a transport position and hydraulically lowered from the transport position to an extended, unfolded position. A down pressure is also typically hydraulically applied to the stationary frame section and the wing sections to prevent the frame sections from pivoting upward due to the resultant force from the ground engaging tools. Moreover, as an air cart is typically used with seeding implements, air cart functions, such as fan operation and seed metering will require hydraulic control. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a hydraulic control apparatus comprised of electronically controlled hydraulic valves for a foldable farm implement that overcomes some of the drawbacks associated with conventional hydraulic systems. The farm implement generally comprises a stationary frame section and a pair of wing sections pivotably mounted to opposed lateral sides of the stationary frame section. A first hydraulic control system is used to control weight transfer to the ground engaging tools mounted to the stationary and wing frame sections. A second hydraulic system is used to fold and unfold the wing sections. A hydraulic control is provided that interfaces with both hydraulic systems to control sequencing of the functions provided by the first and second hydraulic systems. 
     One of the objects of the invention is to provide a less complex hydraulic control for folding and unfolding wing sections of a foldable farm implement and lowering ground engaging tools of the foldable farm implement to a ground engaging position. 
     Another object of the invention is to provide a single remote hydraulic control for controlling a first hydraulic system that controls weight transfer to the ground engaging tools and a second hydraulic system that controls folding and unfolding of the foldable wing sections. 
     It is yet another object of the invention to provide a remote hydraulic control that is operative to disable a first set of hydraulic cylinders that lower the ground engaging tools when the wing sections are being moved to a folded position by a second set of hydraulic cylinders and is further operative to control the second set of hydraulic cylinders to prevent folding the machine when the ground engaging tools are in the ground engaging position. 
     Other objects, features, aspects, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout. 
       In the drawings: 
         FIG. 1  is a pictorial view of a farm planting system having a farm implement hitched to a prime mover; 
         FIG. 2  is a top isometric view of a hoe drill in an unfolded, working position for use with the farm planting system of  FIG. 1 , and shown without ground engaging tools; 
         FIG. 3  is an isometric view of the hoe drill in a folded, transport position; 
         FIG. 4  is a rear isometric view of a front portion of the hoe drill; 
         FIG. 5  is an enlarged view of the front portion of the hoe drill; 
         FIG. 6  is a front isometric view of a center section of the hoe drill; 
         FIGS. 7A and 7B  are isometric views of a valve lockout arrangement according to one aspect of the present invention; 
         FIG. 8  is a schematic representation of a first preferred hydraulic control system for the hoe drill; 
         FIG. 9  is a schematic representation of a second preferred hydraulic control system for the hoe drill; 
         FIG. 10  is a schematic representation of a third preferred hydraulic control system for the hoe drill; and 
         FIG. 11  is an isometric view of a valve-actuating rockshaft of the drill shown in  FIG. 2 ; and 
         FIG. 12  is a section view taken along line  12 - 12  of  FIG. 7A . 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIG. 1 , a planting system  10  according to one embodiment of the invention includes a foldable implement  12 , shown in a field working position, coupled to a prime mover  14 , e.g., tractor, in a known manner. The planting system  10  may also include an air cart  15 , as known in the art. While the invention is applicable with different types of foldable implements, for purposes of illustration, the invention will be described with respect to a hoe drill. 
     Referring now to  FIG. 2 , hoe drill  12  has a center frame section  14  and two wing sections  16 ,  18  pivotally mounted to opposite lateral sides of the center frame section  14 . The wing sections  16 ,  18  are designed to be folded to a transport position in which the wing sections  16 ,  18  are folded over the center frame section  14  to provide a narrow transport configuration that is suited for transport between crops, fields, and along roadways, as well as storage.  FIG. 3  shows the hoe drill  12  in the folded, transport position. 
     The center frame section  14  has a tool bar  20  to which a tongue section  24  is coupled. The tongue section  24  generally consists of a cage  26  having a distal end coupled to the tool bar  22  and a proximate end forming a hitch point  28  for coupling to the prime mover  14  in a conventional manner. Wing sections  16 ,  18  have respective booms  30 ,  32  and draft links  34 ,  36  are interconnected between the cage  26  and booms  30 ,  32 , respectively. The draft links  34 ,  36  are pivotally connected to the cage  26  and the wing booms  30 ,  32  so that as the wing booms  30 ,  32  are drawn inwardly, the draft links  34 ,  36  are drawn to a folded position, as shown in  FIG. 3 . 
     A center sub-frame  38  is pivotally mounted to the center tool bar  20  and is supported above a field surface by wheel  40 . Ground engaging tools (not shown), such as disc openers, may be mounted to the center sub-frame  38  in a known manner. With additional reference to  FIG. 4 , a downforce cylinder  42  is interconnected between the center tool bar  20  and the center-sub-frame  38 . When appropriately activated, the hydraulic cylinder  42  provides a tendency to rotate the center sub-frame  30  about pivot connections  44  to apply a downforce on the sub-frame  38 . 
     Referring again to  FIGS. 2 and 4 , wing section  16  has a right-hand side sub-frame  46  that is pivotally coupled to the wing boom  30 , and is supported above the field surface by wheels  48 . Ground engaging tools (not shown) are attached to the sub-frame  46  in a known manner. Interconnected between the wing boom  30  and the sub-frame  46  are lift cylinders  50 , and when appropriate actuated, pivot the sub-frame  46  about pivot connections  52  to position the sub-frame generally over wing boom  30 . Cylinders  50  also apply a downforce on the sub-frame  46  to lower the openers into engagement with the ground. 
     In a similar manner, wing section  18  has a left-hand side sub-frame  54  that is pivotally coupled to the wing boom  32 , and is supported above the field surface by wheels  56 . Ground engaging tools (not shown) are attached to the sub-frame  54  in a conventional manner. Interconnected between the wing boom  32  and the sub-frame  54  are lift cylinders  58  that when actuated, pivot the sub-frame  54  about pivot connections (not shown) to raise the sub-frame  54  over wing boom  32 . Cylinders  58  also apply a downforce on the sub-frame  54  to lower the openers into engagement with the ground. 
     As best shown in  FIG. 4 , the hoe drill  12  also includes a right-hand side folding cylinder  60  and a left-hand side folding cylinder  62 . The cylinders  60 ,  62  are interconnected between the wing booms  30 ,  32  and center tool bar  20 , respectively. More particularly, a mounting flange  64  is formed on the rear surface of the center tool bar  20  and inward ends of the cylinders  60 ,  62  are pivotally coupled to the mounting flange at pivot points  66 ,  68 , respectively. Outward ends of the cylinders  60 ,  62  are pivotally coupled to mounting flanges  70 ,  72 , respectively, attached to wing booms  30 ,  32 , respectively, at pivot points  74 ,  76 , respectively. When the cylinders  60 ,  62  are appropriately actuated, the cylinders  60 ,  62  pull the wing booms  30 ,  32  inwardly (rearward) so that the wing booms  30 ,  32  rotate about knuckles  78 ,  80  at opposite ends of the center tool bar  20 , respectively. 
     Now referring to  FIG. 4 , the cage  24  is formed by two pair of stacked rails  82 ,  83 ,  84 , and  85  interconnected between center tool bar  20  and hitch point  28 . The stacked rails  82 ,  83 ,  84 , and  85  are angled inwardly from their connection with the tool bar  20  to the hitch point  28  so that the cage  24  has a generally triangular form. The cage  24  also includes a number of cross-bars  86  and posts  88  providing support for the stacked rails  82 ,  83 ,  84 , and  85 . As best shown in  FIG. 5 , the cage  24  includes a swing mount  90  that is interconnected between the pair of stacked rails. A pair of links  92 ,  94  are pivotally coupled to the swing mount  90  and hook around forward ends of the arms  34 ,  36 . Swing cylinders  96 ,  98  are interconnected between the links  92 ,  94 , respectively, and upper rails  82  and  84 , respectively. Thus, when the cylinders  96 ,  98  are actuated, the links  92 ,  94  are rotated so as to open and release arms  34 ,  36  allowing the arms  34 ,  36  to follow the wing sections  16 ,  18  as they pivot about knuckles  78 ,  80 . The flow of hydraulic fluid to cylinders  96 ,  98  is controlled by V 4  and V 8 , or  2 A and  2 B depending on schematic. See  FIGS. 8 and 9 . 
     As shown in  FIG. 6 , a series of valve bodies, generally designated by reference numeral  102 , control the flow of hydraulic fluid to cylinders  42 ,  50 ,  58 ,  60 , and  62 . The valve bodies  102  are mounted to respective mounting brackets (not numbered) that are in turn are attached to, or integrally formed with, the center tool bar  20 . In this regard, the valve bodies  102  are positioned forward of the center tool bar  20 . For the sake of simplicity, the conduits interconnecting the valve bodies  102  and the cylinders  42 ,  50 ,  58 ,  60 , and  62  are not shown, but it is understood that the fluid connection between the valve bodies and the cylinders via such fluid conduits to be within the skill of one in the art. As best shown in  FIG. 7A , the valve bodies  102  include valve bodies  104 ,  106 ,  108 , and  110  which are mechanically linked to a rockshaft  112  which is mounted to the center tool bar  20  by a pair of mounting flanges  114 ,  116 . Operation of the valves  104 - 110  will be described with respect to the schematic of  FIG. 8 . The rockshaft  112  has a tubular body  118  to which a control link  120  is coupled. The control link  120  has a handle  122 ,  FIG. 5 , which enables an operator to remotely rotate the rockshaft  112 . When the rockshaft  112  is rotated, the valves within valve bodies  104 ,  106 ,  108 , and  110  are switched. That is, the valve bodies  104 ,  106 ,  108 , and  110  are mechanically coupled to the rockshaft  112  by linkages  123 . 
       FIG. 8  is schematic of the hydraulic circuit for controlling raising and lowering and folding and unfolding of the hoe drill  12 . The circuit  124  includes a set of pressure reducing/relieving valves  125  that control the hydraulic pressure on the base end of the tool frame cylinders  42 ,  50 , and  58 , and the opener cylinders  126 . Valves V 1 , V 2 , V 3 , and V 4  are contained within valve bodies  108 ,  110 ,  106 , and  104 , respectively. Valves V 1 , V 2  are used to lock out the opener cylinders when the drill  12  is not in the working (field) position. In this regard, when valves V 1 , V 2  are closed the openers cannot be lowered. Valve V 3  is in the left position when the machine is in the working position. This is required to allow hydraulic fluid to return from the rod end to the base of the tool frame cylinder  42 ,  50 ,  58 , and so fluid can return to accumulator  128 . Valve V 4  allows fluid to pass to and from the hydraulic system (not shown) of the prime mover, e.g., tractor. It will thus be appreciated that the hydraulic circuit  124  has a pair of supply ports  130 ,  132  and return ports  134 ,  136 . 
     In the embodiment illustrated in  FIG. 8 , the hydraulic circuit  124  includes two sub-circuits. A frame circuit for controlling the sequencing of the folding and unfolding of the drill as well as raising and lowering the openers, and a swing circuit for controlling swinging the wing booms inward to the transport position and outward to the working position. Each sub-circuit is activated by separate remote controls  138  and  140 . 
     In this regard, when the operator desires to fold the implement, the operator moves the control lever  120  to the transport position, which results in rotation of the rockshaft. With rotation of the rockshaft, valves V 1 , V 2  are moved to the closed position, valve V 3  is in the right hand position, and valve V 4  is in the right hand position. Then using the remote control, the operator can commence folding of the drill. More particularly, the right-hand side of the drill is first raised by activating remote  138 . The operator can swing the right-hand side wing boom  16  inward using remote control  140 . This causes V 5  to open, and V 6  to close. The left-hand side of the drill may now be rotated upward so that the left-hand side sub-frame is rotated over wing boom  18 . This moves V 8  to the left position. Wing boom  18  may then be swung inward to place the drill in the transport position shown in  FIG. 3 . Because valves V 6  and V 7  are one-way blocking (check) valves when closed, pressure can be supplied to the rod end. This allows the operator to raise the sub-frames if they have lowered due to internal valve leakage. 
     One skilled in the art will appreciate that to unfold the drill  12  from the transport position to the working position, the operator again uses remote control  138  to commence the unfolding process. First, the left wing boom is pivoted outwardly to the extended position. Thereafter, the left sub-frame, right wing boom, and then right sub-frame are extended and lowered to the position shown in  FIG. 2 . The operator then moves the control lever  120  to the working setting. This causes rotation of the rockshaft, which in turn causes valves V 1  and V 2  to open to extend the opener cylinders for lowering the openers into engagement with the ground. Valve V 3  is also moved to the open position which allows the sub-frames to move in response to changes in ground contours. Valve V 4  is moved to the closed position. 
     It will be appreciated that the hydraulic circuit  124  provides a controlled sequencing of the folding and unfolding of the drill  12  using a network of shut-off and sequencing valves that are mechanically linked to open and close in a prescribed order. It will further be appreciated that the circuit  124  also permits one hydraulic remote, e.g., remote  138 , to be used to control the weight transfer for the sub-frames, ground engaging tool tip force and packing force, in addition to raising and lowering of the sub-frames. More particularly, the pressure control valves include valves V 9  and V 10  that allow the frame weight transfer and opener tip force to be set at different levels. 
     Using one remote control for weight transfer and tip and packing force provides a timing benefit. That is, when the openers are lowered and engaged in the ground, weight transfer to the frames should be applied. On the other hand, when the openers are in the raised position, weight transfer should be removed to reduce stress on the sub-frames. By using a single remote, this application and reduction of weight transfer will always occur. Additionally, when folding into the transport position, the openers will be raised fully off the ground before the sub-frames are lifted off the ground. Thus, the possibility of the operator forgetting to raise the openers before transport is avoided. As a result, the circuit  124  ensures that no openers are too low before the drill is folded to the transport position. 
     In other words, utilizing a single control for the pressure relief sub-circuit and the shut-off/sequencing sub-circuit provides: (1) no weight transfer to the sub-frames will occur until the openers are lowered; (2) all weight transfer to the sub-frames will be removed before the openers are raised; (3) openers will be raised before the sub-frames are raised; and (4) the sub-frames will be lowered before the openers are lowered into ground engagement. 
       FIG. 9  is a schematic layout of another preferred hydraulic circuit for use with the drill shown in  FIG. 2 . In this embodiment, the circuit  142  is substantially similar to circuit  124  described above, but utilizes solenoid controlled valves rather than mechanically actuated valves to control the raising and lowering and folding and unfolding of the drill. 
       FIG. 10  shows yet another schematic layout of a preferred hydraulic circuit  144  according to another aspect of the invention. In this embodiment, which for purposes of illustration has a layout similar to the circuit of  FIG. 9 , the swing circuit and the frame circuit are on the same remote  146 . Thus, in this embodiment, a single hydraulic remote control may be used to control raising and lowering of the openers, raising and lowering of the sub-frames, and swinging in and out the wing booms. Circuit  144  includes ON/OFF valve  148  to activate/deactivate the swing sub-circuit. 
     As described above, one of the drawbacks of conventional foldable implements is the possibility that the implement frame could be unintentionally lowered while in the transport position. If the valves are switched to the field setting while the implement is transitioning, or is already in, the transport position, the implement frame could be free to pivot and lower without control. To prevent such an occurrence, the present invention provides a lockout arrangement  150 , which is best illustrated in  FIGS. 7A and 7B . 
     The lockout arrangement  150  generally consists of a push-pull cable  152  and a sliding pin  154 . The sliding pin  154  is attached to an end of the push-pull cable  152  adjacent the rockshaft  112 . The opposite end of the push-pull cable  152  is attached, at point  156 , to one of the wing sections, such as sub-frame  46 . 
     Alternately, the push-pull cable  152  could be attached to sub-frame  54 . In either case, when the implement is in the field position, e.g., the wing sections  16 ,  18  are unfolded and all sub-frames are lowered, such as illustrated in  FIG. 2 , the center tool bar and the wing booms are generally parallel to the ground and is free to rotate approximately  15  degrees away from or toward the ground to account for changes in ground contours, field obstructions, and the like. When the operator desires to place the implement in its transport position, the operator activates control lever  120  which causes rotation of the rockshaft  112 . As the rockshaft  112  rotates, the positions of the valves  104 - 110  change, as described above. In one preferred embodiment, after the control lever has been activated to change the valves to the “transport” setting, the operator activates the remote control that causes the right-hand side sub-frame to rotate over the wing boom  30  followed by swinging in of the wing boom  30   
     As sub-frame  46  is rotated, the lockout arrangement  150  of the present is activated. More particularly, as sub-frame  46  rotates over tool bar  30 , the attached end of the push-pull cable  152  pushes the cable inward, i.e., toward the rockshaft  112 . With continued rotation of the sub-frame, the pin  154  moves toward a bore  158 ,  FIG. 11 , formed in an end of the rockshaft  112 . When the sub-frame  46  has reached its fully rotated position, the pin  154  will slide into the rockshaft  112  thereby preventing rotation of the rockshaft  112 . As a result, if the control lever  120  were to be activated while the implement is folding or has been folded, the rockshaft  112  will not be allowed to rotate. Since the rockshaft  112  is prevented from rotating, the valves controlled by rotation of the rockshaft  112  cannot change positions. Most importantly, since valves V 1  and V 2  are closed when the rockshaft  112  rotated by movement of the control lever  120  to the transport setting, locking out rotation of the rockshaft  112  prevents unintentional movement of the rockshaft  112  to the “working” setting via movement of the control lever  120 . Since hydraulic fluid cannot flow, the implement cannot rotate or pivot as may otherwise occur without the lockout arrangement  150  of the present invention. When the implement is unfolded, the pin  154  will automatically be withdrawn from the rockshaft  112  which allows the rockshaft  112  to rotate when the control lever is moved to the “working position”. 
     The lockout arrangement  150  includes a flange  160  mounted to the tool bar  20  and adjacent to the bore  158  formed in the end of the rockshaft  112 . The flange  160  carries a bushing  162  that aligns with bore  158  when the rockshaft  112  is rotated to the transport position. The pin  154  slides within bushing  162  as the wing section  16  is folded. As described above, when fully folded, the pin  154  will slide through the bushing  162  into the bore  158  of the rockshaft  112 . Since the bushing  162  is mounted to the flange  160 , which is fixedly attached to the tool bar  20 , rotation of the rockshaft  112  will be prevented when pin  154  is positioned within the bore  158 . 
     It will be appreciated that the present invention provides a hydraulic circuit for use with a farm implement, such as a hoe drill, which provides a number of performance benefits over conventional hydraulic circuits or systems. The hydraulic circuit is arranged and configured to sequence the raising and lowering and folding and unfolding of the implement in a predefined, orderly manner. Weight transfer to the frames of the implement, opener tip force and packing force, and raising/lowering of the frames and transitioning between field and transport position can be controlled using a single remote. Using a single remote also provides a preferred sequencing of the application/removal of weight to the frames and raising/lowering of the implement. In one embodiment, a single remote control can be used to control both a frame lowering/raising circuit and a boom swing circuit. Further, according to another aspect of the invention, a valve lockout arrangement is provided to prevent the flow of hydraulic fluid to the cylinders that raise and lower the openers when the implement is in, or being transitioned to, the transport position. 
     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. 
     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.