Abstract:
A hydraulic control for a folding tool bar which has a transport width less than half the field working width. Restrictors are added in series in the right-hand folding lines to cause the left-hand outrigger to fold to the transport position first. A one-way plunger operated ball check valve located in the hinge area between the main frame and an outrigger frame bypasses the restrictors for the first five degrees of fold and for the complete unfold cycle. The outriggers can therefore be lifted together at the start of the fold cycle during turns in the headlands. For complete folding to the transport position the left-hand outrigger folds first with the end of the right-hand outrigger positioned above it. The ball check valve causes the right-hand outrigger to unfold out of the path of the left-hand outrigger during the unfolding cycle.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to a folding toolbar and more specifically to a hydraulic sequence control for folding the outrigger frames on a toolbar. 
     As tractors are made larger and farms increase in size, farm implements are widened to cover a larger swath during each pass through the field. Transporting implements continues to be a source of difficulty since the transport width must be sufficiently narrow to pass through gates and over bridges and public roads and the like. Folding toolbars have been devised with a main frame having a pair of outrigger frames hinged to its ends for folding upwardly about a horizontal pivot to a narrow transport position. When the outrigger frames have a combined width less than the width of the main frame, they can be folded together approximately 180° to a position directly over the main frame. However, a problem exists when it is desirable to have an implement transport width less than half the field work width, since both outriggers cannot fold 180° without interference from each other. Commonly each of the outriggers is folded slightly more than 90° so that it projects upwardly and just inside the main frame. This arrangement does not provide as compact and stable transport configuration as one with outriggers which fold approximately 180°. 
     Heretofore it was not practical to add extensions to the 180° fold outrigger frames, for example to increase row crop cultivator width from 16 to 18 rows, because the extensions would interfere with each other when the outriggers were folded between the transport and field-working positions. To add outrigger extensions to an existing 180° wing fold arrangement would require a new or extensively revised hydraulic folding system. 
     When turning in the headlands with a tractor mounted wingfold toolbar, it is often desirable to activate the hydraulic folding system and lift to outriggers approximately 5° to prevent the outer ends of the implement from contacting the ground during the turn. Previously available hydraulic systems for raising the outriggers included specially designed dual function cylinders for operating in one mode during turns and in another mode during folding and unfolding of the outriggers between the transport and field-working positions. These cylinders are more complex and expensive than other types of cylinders utilized for folding and unfolding the outriggers. 
     It is therefore an object of the present invention to provide an improved hydraulic folding system for wing-fold implements. 
     It is another object of the invention to provide a relatively inexpensive and simple folding sequence control for wing-fold implements. 
     It is yet another object to provide an improved hydraulic system for folding a wing-fold implement to less than half its field-working width while providing a relatively low, stable transport configuration. 
     It is a further object to provide a simple and yet reliable control for raising the outriggers of a folding toolbar together during the first portion of the fold cycle and thereafter sequencing the folding to provide the desired movement of the outriggers to and from the transport position so they do not interfere with each other. It is also an object to provide such a control which does not require special hydraulic cylinders or more than one hydraulic outlet. 
     It is a further object of the invention to provide a control which can be added to an existing 180° folding toolbar to permit the outriggers to be extended to a total combined width greater than the width of the main frame while preventing interference between the outriggers during folding and unfolding, and while causing the outriggers to fold in unison for the first part of the fold cycle. 
     The first outrigger of a 180° folding toolbar is folded to a 180° position first after which the second outrigger is folded to about a 150° position where it is supported just above the end of the first outrigger. Restrictors are added in series to the hydraulic line for the second outrigger cylinder. A one-way plunger operated ball check valve bypasses the restrictors for the first 5° of fold. The check valve is located on the main frame in the hinge area and is operated by an arm on the outrigger. In the field-working position of the toolbar, the plunger is depressed so that when hydraulic pressure is applied to the cylinders the outriggers raise together for the first 5°. At this point, the plunger closes the check valve to slow the folding of the second outrigger. During unfolding the check valve allows the hydraulic fluid to bypass the restrictors so the first and second outriggers unfold at the same speed, thus insuring that the second outrigger will be out of the way of the first outrigger. This arrangement permits the total width of the outriggers to be greater than the width of the main frame, and provides a simple and yet reliable means for raising the outriggers together during the first portion of the fold cycle. 
     These and other objects, features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description taken with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1a is a rear view of a wing-fold toolbar embodying the present invention mounted on a tractor and in the field-working position. 
     FIG. 1b is a view similar to FIG. 1a but showing the outriggers raised together to an intermediate position approximately 5° above the horizontal. 
     FIG. 1c is a view similar to FIG. 1a but showing the outriggers folded approximately midway between the field-working and the transport positions. 
     FIG. 1d is also a view similar to FIG. 1a but showing the outriggers in the transport position. 
     FIG. 2 is a top perspective view of the right-hand outrigger hinge area, with the outrigger in the position shown in FIG. 1a, and showing the plunger operated check valve of the present invention with the plunger depressed. 
     FIG. 3 is an end perspective view of the right-hand outrigger hinge areas, with the outrigger in the position shown in FIG. 1d, and showing the valve operating arm and the check valve with the plunger released. 
     FIG. 4 is a schematic diagram of the hydraulic system. 
     FIG. 5 is an enlarged rear view of the right-hand hinge in the position shown in FIG. 1d. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, in FIG. 1 there is shown a tractor 10 supporting a 180° folding toolbar from a 3-point hitch or the like (not shown) for vertical movement with respect to the ground. A rear lift assist wheel (not shown) can be attaced to the toolbar if necessary for added support and lifting capacity. The toolbar 12 is generally of a conventional design with first and second outrigger frames 14 and 16 pivotally connected to a main frame 18 at its left and right ends by hinges 20 and 22, respectively. Such a toolbar is commercially available, for example with the John Deere model 85 Row Crop Cultivator. However, the toolbar 12 has been lengthened by connecting extensions 24 and 26 to the ends of the outrigger frames 14 and 16 so that the total width of the outrigger frames is greater than the width of the main frame 18. Plates 28 and 30 are welded to the ends of the outrigger frames 14 and 16 and to the innermost ends of the extensions 24 and 26 and are connected together by bolts 32, or other suitable conventional means are utilized to add the extensions 24 and 26. The extensions 24 and 26 may also be formed as integral parts of the outrigger frames. Ground-working tools 34 such as cultivator shovels are supported from the toolbar 12 by shank assemblies 36. The extensions 24 and 26 are added, for example, to convert a conventional 16-row cultivator into an 18-row cultivator. 
     Hydraulic cylinders 38 and 40 are connected to their rod ends to the hinges 20 and 22, respectively, and at the opposite ends to the main frame 18. The cylinders are connected to a source of hydraulic pressure P at a hydraulic outlet on the tractor 10, and are extendable and retractable to move the outriggers between the unfolded field-working position (FIG. 1a) and the folded transport position (FIG. 1d). In the preferred embodiment, cylinders 38 and 40 are essentially identical and have equal displacement. 
     The hinges 20 and 22 are substantially identical so only the right-hand hinge 22 will be described in detail. Side brackets 42 extend upwardly from the main frame 18 and include apertures 44 (FIG. 3) laterally outwardly of main frame end wall 46. A connecting portion 48 is welded to the side brackets 42 and to the end wall 46. The portion 48 extends vertically from the end wall 46 and inwardly in a substantially horizontal attitude from bend location 50, terminating at a wall 52. A reinforcing spacer 54 is welded on each side of the hinge 22 to the side brackets 42 and the connecting portion 48. 
     The hinge 22 also includes side brackets 56 which extend upwardly from the outrigger frame 16 and inside the main frame side brackets 42. The brackets 56 extend laterally from the end of the outrigger frame 16 toward the main frame 18. A tubular member 58 is welded between the side brackets 56. The outrigger frame end plate, indicated generally at 60 is welded to the side brackets 56 and the tubular member 58. A hinge pin 62 is inserted through the apertures 44, spacers 54 and tubular member 58 to pivotally connect the outrigger 16 for rocking with respect to the main frame 18 about the generally horizontal and fore-and-aft extending axis of the hinge pin. 
     Links 64 are pivotally connected at one end to the outrigger brackets 56 by a pivot pin 66. Links 68 (FIG. 1b) are connected at one end to the main frame brackets 42 by a pivot pin 70. The opposite ends of the links 64 and 68 are pivotally connected together and to the rod end of the cylinder 40 by a pin 72, so that as the cylinder 40 is retracted the outrigger 16 will be pivoted about the axis of the pin 62 in the counterclockwise direction as viewed in FIGS. 1a-1d and 5. As the cylinder is extended, the outrigger 16 will pivot in the clockwise direction. Construction and operation of the left-hand hinge 20 is substantially identical to that of the right-hand hinge 22. Such hinges are the same as provided on the aforementioned model 85 Row Crop Cultivator. 
     A one-way plunger operated ball check valve assembly 74 (FIGS. 2-4) is attached to the main frame 18 near the right-hand hinge 22 by a pair of bolts 76 which pass through valve body 78 and through the horizontally disposed section of the connecting portion 48. A plunger or activator 80 projects laterally outwardly from the valve body and is biased toward an extended position wherein the ball check valve is in the position shown in FIG. 4 to allow unrestricted flow to the right only. A support block 82 of a valve operating arm assembly 84 is welded or otherwise connected in a suitable manner to the inside of the outrigger side bracket 56 and carries a bolt 86. The head of the bolt 86 describes an arc as the hinge 22 rocks about the hinge pin 62. The arc intercepts the end of the plunger 80. The bolt 86 is biased toward the plunger 80 (as viewed in FIG. 2) by a spring 88 carried on the shank between the support block 82 and the head. A pair of nuts 90 (FIG. 3) are threaded on the shank to maintain the bolt 86 on the support block 82. By turning the nuts 90, the hinge position at which the plunger 80 is depressed can be adjusted. In the preferred embodiment, the bolt 86 is adjusted to maintain the plunger depressed when the outrigger 16 is in the horizontal position (FIG. 1a) to a 5° above horizontal or lifted position (FIG. 1b). The check valve 74 and the valve operating arm 84 can be added to the hinge of an existing folding toolbar to modify the fold and unfold cycle of the tool bar. 
     Hydraulic line 92 connects the check valve 74 to the hydraulic circuit for the right-hand cylinder 40 as shown in FIG. 4. Two restrictors 94 are placed in series with hydraulic line 96 leading to the cylinder 40. The check valve 74 is connected in parallel with the restrictors 94. The parallel combination of the restrictors 94 and check valve 74 is connected to one port of a hydraulic outlet 97 on the tractor, or other source of hydraulic fluid, by line 98. The cylinder 40 is connected to the other port of the outlet 97 by line 100. Hydraulic fluid is selectively directed by the pump P from a reservoir R through a conventional operator control valve 101 on the tractor to extend and retract the cylinders 38 and 40. The left-hand cylinder 38 is connected to the ports, and in parallel with lines 98 and 100, by lines 102 and 104. When the plunger 80 is depressed by the valve operating arm 84, hydraulic fluid can flow freely in either direction through the valve 74 between the lines 96 and 98, bypassing the restrictors 94. When the plunger is extended, the valve is in the position shown in FIG. 4 and flow is restricted to the left from the line 96 to the line 98, but the fluid can flow freely toward the right through the check valve. 
     In operation, with the tool bar 12 in the position shown in FIG. 1a, the valve operating arm 84 acts against the plunger 80 to maintain the check valve 74 in the uppermost position (FIG. 4) so that hydraulic fluid can flow freely from the cylinder 40 through the lines 96 and 98, bypassing the restrictors 94. Therefore when the operator moves the valve 101 to apply hydraulic pressure to the lines 100 and 104 and retract the cylinders 38 and 40, both outriggers 14 and 16 will raise together at approximately the same rate until the arm 84 allows the plunger 80 to extend. Once the plunger 80 is extended hydraulic fluid can no longer bypass the restrictors 94 while the cylinder 40 is retracting. The bolt 86 of the arm 84 is adjusted so that the outriggers 14 and 16 will fold together during the initial portion of the fold cycle, preferably about the first 5° (FIG. 1b), to facilitate turning in the headlands. Thereafter with continued retraction of the cylinders, hydraulic fluid flow from the right-hand cylinder must pass through the restrictors 94 because of the check valve 74, thereby slowing down the folding of the right-hand outrigger 16 (FIG. 1c) so the opposite outrigger 14 reaches its folded transport position first. In the preferred embodiment, the restrictors 94 are selected such that the folding rate of the right-hand outrigger 16 will be about 0.577 times the rate of the outrigger 14 after they are folded beyond the preselected angle at which the plunger 80 is extended. 
     After the left-hand outrigger 14 reaches its fully folded position, which in the preferred embodiment is 180° from the field-working position, the right-hand outrigger continues to fold as the cylinder 40 is retracted until the extension 26 is in a preselected position just above or overlapping the upwardly extending shank assemblies 36 on the left-hand extension 24 (FIG. 1d). In the preferred embodiment the preselected position is about 150° from the field-working position or at an angle slightly less than the angle where interference between the extended outriggers begins to occur. A support stand 108 is mounted on the main frame 18 by a pair of U-bolt brackets 110 to prevent the outrigger 16 from pivoting beyond the desired transport position angle and to support the outrigger 16 during transport. Another support stand 112 is mounted on the main frame 18 by a single U-bolt bracket 114 to support the outrigger 14 in the 180° folded position. 
     To unfold the outriggers from the transport position shown in FIG. 1d to the field-working position shown in FIG. 1a, the cylinders 38 and 40 are extended by supplying fluid under pressure to the lines 102 and 96. Since the check valve 74 is one-way only, fluid can flow from the line 98 to the line 96 through the valve to bypass the restrictors 94 so both cylinders 38 and 40 will extend at approximately the same rate to unfold the outriggers 14 and 16 at the same rate. Therefore, the right-hand outrigger 16 will be out of the way of the left-hand outrigger 14 during unfolding. 
     The above-described hydraulic control allows extensions to be easily added to a 180° folding toolbar without extensive modifications and permits folding and unfolding of the outriggers without interference from each other. The hydraulic control permits the outriggers to be raised together during the first portion of the fold cycle for turns in the headlands. 
     Having described the preferred embodiment, it will be apparent that modifications can be made without departing from the scope of the invention as defined in the accompanying claims.