Rearwardly folding implement
BACKGROUND OF THE INVENTION 
     The present invention relates generally to foldable multisectional agricultural implements and more specifically relates to rear folding implements having means thereon to automatically secure the folded sections in either an operative or transport configuration. 
     Modern agricultural implements are becoming larger and wider as the profits a farmer is able to realize become more dependent upon his ability to realize higher levels of productivity. Naturally as these implements increase in size, they become much more difficult to store and transport. 
     To overcome the problems inherent in storing and transporting large and wide implements, several approaches have been utilized. For example, some implements are folded upwardly to reduce the transport width and depth. Other implements provide means for folding the sections forwardly while yet other approaches utilize rearwardly folding wing sections. 
     Upwardly folding implements are limited both with respect to the weight which can be lifted to a vertical position and the ultimate height which can be tolerated during transport. Further, such implements must provide means for stabilizing the tool-laden and elevated sections during the transport operation. 
     Forwardly folding implements often require various means to secure the folded wing sections to the tractor to minimize skidding and tracking problems encountered during turning maneuvers. 
     Many multi-sectional agricultural implements utilize rear folding wing sections to reduce the width required for transport and storage. Unless some provision is made for eliminating the interference between the tools adjacent pivotal connections, the tools must be removed. One approach to solving this interference problem provides for rotation of the tools to an elevated position prior to folding of the implement sections to eliminate interference. Such a solution, however, requires expensive hydraulic systems and additional manufacturing as well as maintenance expenses. A further problem encountered with existing rear fold implements involves steering during transport operations. Rearwardly folded wing sections often tend to swing excessively during turning unless they are latched together with some rigid means. Those means provided today for latching the folded sections together are manual and require the operator to leave his cab to latch and unlatch the sections. Further, these means are rigid and do not permit the trailing sections to track during turning maneuvers, but thereby often cause the sections to skid. 
     SUMMARY OF THE INVENTION 
     Applicant&#39;s invention has overcome the above-mentioned problems and provides a rear folding multi-sectional implement frame which eliminates interference between tools adjacent sectional pivotal joints and can be automatically latched in either the operative or transport position. 
     It is a primary object of the present invention to provide a means for folding and unfolding large and heavy agricultural wing sections. 
     It is further an object to provide means for automatically securing the wing sections in either their operative or transport configuration. 
     It is yet another object of the present invention to provide a rear folding implement which eliminates tool interference at the joints between the sections. 
     Another object of the present invention is to provide means to minimize skidding of the trailing wing sections during transport turning maneuvers. 
     Yet another object of the present invention is to provide the locking means with some degree of yieldability to avoid structure failure of the mechanism during operation and transport. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a three-sectioned implement embodying the invention. 
     FIG. 2 is an enlarged plan view of the folding linkage and latching mechanism as positioned when the wing sections are in the transport position. 
     FIG. 3 is a partial side view of the invention illustrating the latching mechanism. 
     FIG. 4 is an enlarged plan view of the folding linkage and latching mechanism as positioned when the wing sections are in the transverse operational position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings and in particular to FIG. 1, there is illustrated a multi-sectional implement indicated generally at 10, having a U-shaped center frame or section 12 with a central transversely extending structural member 14, a pair of transversely spaced rearwardly extending leg members 16 and outer frames or side sections 18. Each side section 18 includes a caster wheel 20 which permits that section to be easily moved between transverse operational and rearwardly extending transport positions. Coupling each side section 18 with its respective center section leg member 16 are horizontally extending pivot pins 22 and vertically extending rear pivot pins 24, the latter being treated as rear pivot means on the ends of the central frame 12. 
     As is best seen in FIGS. 2 and 3, a linkage structure 26 is provided between each leg member 16 and its respective side section 18 to secure that side section 18 in either its operational or transport configuration. While the illustrated linkage structures 26 in FIGS. 2 and 3 include a pair of first rigid links 28 pivotally connected to a front pivot pin 30 and carried by ear 32 which projects from leg or structural member 16, a single first link 28 would provide a workable mechanism. Each first link 28 is rotatably connected with its respective leg member 16 for rotational movement about a vertical axis between forwardly folded and rearwardly extending positions. A pair of second rigid link members 34 have their one end universally connected with the forward edge of the side section or outer frame 18 and their other end connected with the first link 28 by pin member 36. Similarly only a single second link is required for the invention. 
     Tools 38, which are shown as cultivator shovels but which may be of any other variety such as planters, chisel plows, rod weeders etc., are carried on the forward beam or structural member 14 and project rearwardly into a tool-receiving area defined by the front structural member 14 and the side structural members 16 of the central frame. Similar tools 38 are carried on and extend rearwardly from outer frames 18. 
     A locking means 40 engageable with each first rigid link 28 is carried by leg member 16 to secure the first link 28 in either its forwardly folded or rearwardly extended position. In the preferred embodiment, the locking means 40 includes a first forward latching member 42 carried by an L-shaped arm 44. The arm 44 in turn is pivotally connected to the outer section 12 by a vertical pivot pin 46 positioned forwardly of the link pivot pin 30. A second latching member 48 is included in the locking means 40 to secure the link 28 in its rearwardly extended position. The second latching member 48 is carried by the arm 50 which in turn is pivotally connected to ear 52 by vertical pivot pin 54. As will later become apparent, it is important that the pin 54 supported by the ear 52 be transversely offset sufficiently to be outwardly positioned relative to the vertical pivot pin 24. 
     A latch activating hydraulic cylinder 56 has its base end connected to the central transverse member 14 and its ram end connected to the first activating arm 44. Interconnecting the arms 44 and 50 and their respective latches 42 and 48 for simultaneous movement is a rigid rod 58. As can be observed from FIGS. 2 and 4, both arms 44 and 50 will be moved to either their opened or closed positions as the hydraulic cylinder 56 is retracted and expanded. In this way the operator need activate the latching mechanism only to open the latches 42 and 48 so that the side frames 18 can be shifted to their other position where the latches 42 and 48 can then be closed. 
     In operation the linkage 26 is as illustrated in FIGS. 1 and 3 and the wing sections 18 are transversely aligned and offset rearwardly from the central transverse member 14. In this position the latch member 42 secures the first link 28 in its forwardly position and the second link 34 acts under tension to secure each wing section 18 in its transversely aligned position. The horizontally positioned hinge pivot pins 22 permit each wing section 18 to ride over ground contours different than those encountered by the center 12 or outer wing sections 18. To avoid structural damage to the second link 34 during movement of the wing section 18 over such ground contours, a ball joint 60 is provided between the second rigid link 34 and its respective wing section 18. 
     To fold the wings rearwardly for transport, the latch arms 42 and 48 are rotated, by hydraulic cylinder 56, to unlatch link pin 36 and the implement is then moved slowly ahead. As the implement is advanced, the wing sections 18 supported on caster wheels 20 swing around behind the center section 12. With the U-shaped center section tools 38 mounted on the transverse forward portion of the center section 12, tool interference is eliminated at the hinge joints between the center section 12 and the respective wing sections 18 as the wing sections 18 move into their transport position. 
     As each wing section 18 is slowly moved into fore-and-aft trailing positions, the links 28 and 34 move to an extended condition until the first link 28 is moved into abutment with a resilient pad 62 mounted on the ear 52 of the leg member 16. At this time the operator will then activate the latching rod 58 to lock the swinging end of the first link 28 into its rearward position and to secure the wing section 18 in its transport position. It is important that the ear or bracket 52 positions its pad 62 and latch 48 in a transverse outward offset relation with respect to the beam 16 and its rear pivot 24. This causes the adjoining ends of links 28 and 34 to be offset from the pivot 24 and the link 34 to be at an angle to the outer frame 18 when the latter is in fore-and-aft disposition. This restricts the outer frame 18 against lateral shifting and thus prevents the tools 38 on the outer frames 18 from interferring with those on the central frame 12. 
     In this position the second rigid link 34 will hold the trailing side section 18 in position since the forward end of the second link 34 is locked against movement by the rearward latch member 48. However, it is desirable that each outer frame or trailing wing section 18 be able to swing transversely to some degree. Otherwise, the sections 18 will skid rather than trail during turning maneuvers and possibly cause a loss of steering control by the operator. To overcome this problem, the resilient pad 62 between each leg member 16 and the first rigid link 28 permits the linkage 26 to move slightly during transport as the wing section 18 encounters ground contour changes or the implement is turned. 
     With the locking linkage provided, an operator need not leave his tractor to fold or latch the sections into either operating or transport position. Neither must he transport bars or links to lock the wing sections into place for transport as is required with many of today&#39;s foldable implements.