Abstract:
A flexible rockshaft includes joint structure facilitating the adjustment of the rotational angle of rockshaft segments relative to each other. A link inserted between a rockshaft segment and the rockshaft flex member rotates on the same or a parallel pivot as adjacent rockshaft segment, and an adjustable length connecting mechanism on the link provides angular adjustment. In one embodiment, shims supported on the link are selectively clamped between a threaded stop and an internally threaded link. The number of shims may be easily varied to change the angular position of one rockshaft segment relative to the adjacent segment. In another embodiment, a simpler threaded member with positioning nuts is located on the additional link and provides inexpensive angular adjustability.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to a rockshaft for an implement and, more specifically, to a rockshaft having two or more sections connected by a joint to provide flexibility.  
       BACKGROUND OF THE INVENTION  
       [0002]     Implement frame flexibility is required for proper operating depth and consistent seed placement across a wide seeding implement. A multi-section agricultural implement frame with a segmented and jointed rockshaft is often used with such implements. An actuator attached to one segment rotates the rockshaft segments to raise and lower tools connected to the frame. In many currently available seeding and tillage implements, the rockshaft is connected to lift wheel assemblies that rotate relative to the frame with movement of the actuator to change frame height. The joints connecting rockshaft segments transmit rockshaft rotation and facilitate pivoting of the frame sections when changes in terrain are encountered or when the implement frame is folded and unfolded between field-working and transport positions. Loads on the joints can be substantial, particularly when the rockshaft is part of a lift system on large tillage and seeding implements.  
         [0003]     To adjust the operating depth of tillage or seeding tools on one frame section relative to the tools on another section, some implements have adjustable length links located between the rockshaft and the support wheels. Other adjustment structures include an adjustable turnbuckle between the mainframe and outer section rockshafts. If additional wheel assemblies are connected to the rockshaft outboard of the inner rockshaft section, individual adjustment at each outboard wheel assembly may be required to change relative operating depth. Providing convenient, consistent and precise wheel assembly adjustments is continuing source of problems with such rockshaft assemblies.  
       SUMMARY OF THE INVENTION  
       [0004]     It is therefore an object of the present invention to provide an improved flexible rockshaft structure for an implement. It is another object of the invention to provide such a rockshaft structure which overcomes most or all of the aforementioned problems.  
         [0005]     It is a further object of the present invention to provide an improved flexible rockshaft structure which facilitates adjustment of the operating depth of tillage or seeding tools on one frame section relative to similar tools on another section. It is yet another object to provide such a rockshaft which provides consistent, repeatable and precise height adjustment.  
         [0006]     A segmented and jointed rockshaft includes joint structure facilitating the angular adjustment of the rockshaft sections relative to each other. An additional link is inserted between a rockshaft segment and the rockshaft flex member. The additional link rotates on the same or a parallel pivot as adjacent rockshaft segment. Rotational position of the additional link relative to the rockshaft segment is controlled by a connecting mechanism. In the embodiment shown, shims supported on the additional link are selectively clamped between a threaded stop and an internally threaded link. The number of shims may be varied to change the angular position of one rockshaft segment relative to the adjacent segment. Convenient angular adjustment of the rockshaft segments is provided. One adjustment mechanism controls operating height of all frame sections outboard of the mechanism, thereby saving adjustment time and steps. The shim adjustment has discrete steps which make readjustments more consistent and predictable.  
         [0007]     In an alternative design, a simple threaded member located on the additional link includes positioning nuts to provide inexpensive angular adjustability.  
         [0008]     These and other objects, features and advantages of the present invention will become apparent from the description which follows taken in view of the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is perspective view of a right-hand portion of a multi-section implement in a folded position and having a flexible rockshaft with the implement sections.  
         [0010]      FIG. 2  is a perspective view of the portion of the implement of  FIG. 1  in the field-working position with parts removed to better show the interconnections of front lift wheels with the flexible rockshaft.  
         [0011]      FIG. 3  is an enlarged perspective view of a portion of the implement of  FIG. 1  in the field-working position.  
         [0012]      FIG. 4  is an enlarged perspective view of one of the flexible joints between the implement sections.  
         [0013]      FIG. 5  is a view of an alternate embodiment of a flexible joint. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]     Referring now to  FIGS. 1-3 , therein is shown a right-hand portion of a multi-section flexible implement  10  having a main frame  12  with a plurality of implement frame sections including sections  12   a ,  12   b , and  12   c . The frame  12  is supported for transport by front and rear ground wheel assemblies  14  and  16 . A flexible rockshaft member  20  having rockshaft segments  20   a ,  20   b , and  20   c  is supported from the rear of the main frame sections  12   a - 12   c  and is connected to the ground wheel assemblies  16 . Links such as shown at  18   a ,  18   b , and  18   c  connect the flexible rockshaft member  20  with the front ground wheel assemblies  14   a ,  14   b  and  14   c . Cylinders  22  are connected between the main frame section  12   a  and the rockshaft member segment  20   a . Operating the cylinders  22  to rotate the rockshaft member  20  in a clockwise direction rocks the wheel assemblies  14  and  16  upwardly to lower the main frame  12  to a field working position. The rear wheel assemblies  16  are raised off the ground, and depth control is provided by the front wheel assemblies  14  through the rockshaft member  20  and the links  18   a - 18   c . To lift the frame  12  for road transport, the rockshaft member  20  is rotated in the opposite direction so the wheel assemblies  14  and  16  rock downwardly with respect to the frame  12 . For field transport, the rear wheel assemblies  16  remain off the ground, but the forward wheel assemblies  14  are lowered sufficiently for tool ground clearance. The left-hand portion of the implement  10  is generally the mirror image of the right-hand portion.  
         [0015]     A plurality of tools, shown in  FIG. 2  as hoe drill openers  24 , are supported from the frame  12  for opening a furrow and depositing material such as seed. Trailing press wheel gangs  30   a ,  30   b  and  30   c  include drawbar structures  32   a ,  32   b  and  32   c  pivotally connected the forwardly adjacent frame section  12   a - 12   c  for firming the soil over the material deposited in the furrows. The drawbar structures  32   a - 32   c  are connected to the rockshaft member  20  by walking beam linkages  36   a - 36   c  to provide lift and support for the gangs. The implement  10  is relatively large, and the rockshaft member  20  is subject to heavy loading. As shown in the figures, at least the outer segments of the rockshaft member  20  also act as section beams, which further increases the loading and bend forces on the member  20 .  
         [0016]     To facilitate folding and unfolding of the frame sections  12   a - 12   c  relative to each other and flexing of the frame  12  during field working operations, flexible joint structure  40  connects segments of the rockshaft member  20 . The flexible joint structure  40  includes adjustment structure  42  for selectively changing the angular position of adjacent rockshaft sections, thereby facilitating implement leveling and relative frame height of the frame sections.  
         [0017]     As best seen in  FIG. 4 , the flexible joint structure  40  includes a first hinge member  50  fixed to the outermost end of the rockshaft segment  20   a . An adjustment hinge member  52  is connected by a pivot  54  to the first hinge member  50  for rocking relative to the rockshaft segment  20   a  about a generally fore-and-aft extending pivot axis  56 . The hinge member  52  extends downwardly and outwardly from the pivot  54  to a connection with an upright plate  58 . A second plate  60  is pivotally supported from a forward end of the plate  58  by a pivot pin  62  for rocking about an axis  66  generally parallel to the longitudinal axis of the rockshaft segment  20   b . The innermost end of the rockshaft segment  20   b  is fixed to the outer face of the plate  60 . A bracket  68  fixed to the inner end of the rockshaft segment  20   b  projects rearwardly to a pivotal connection  70  with a lowermost portion of an adjustable length member or trunnion  72 . The member  72  has an upper end connected to an outwardly projecting bracket  74  fixed to the outer face of the plate  58 . By varying the length of the member  72 , the angular position of the rockshaft segment  20   b  relative to the plate  58 , and thus the relative angle between the segments  20   a  and  20   b , can be adjusted.  
         [0018]     The adjustable length member  72  shown in  FIG. 4  includes a lower cylindrical portion  82 , and the pivotal connection  70  includes a bolt with a bushing extending through aligned apertures in the plate  60  and the bracket  68 . The bolt extends through a washer  84  and through the portion  82 , and the bolt and bushing project through a slot  86  in the plate  58 . A nut  87  on the bolt is tightened, so that the bolt, bushing, end washers and the nut form the equivalent of a double headed pin which is free to slide along the slot  86 .  
         [0019]     A threaded shaft  90  is rotatably supported by the bracket  74  and includes a threaded end extending into a threaded internal bore portion of the cylindrical portion  82 . The upper end of the shaft  90  is hexagonal, and by inserting a tool over the end and rotating the shaft, the pivot  70  moves relative to the slot  86  to rotate the plate  68  and rockshaft segment  20   b  about the pivotal axis  66  and change the angle of the segment  20   b  relative to the segment  20   a.    
         [0020]     To provide a strong but adjustable connecting link between the plates  58  and  68  and provide a visual indicator of the angular adjustment between adjacent rockshaft segments  20   a  and  20   b , the flexible joint structure  40  includes indexing structure  100 . The indexing structure  100  includes shims  102  and  104  conforming generally to the shapes of the trunnion and bracket. Individual shims  102  and  104  are pivotally connected to the joint structure  40  and facilitate incremental adjustment of the angular position of the first rockshaft segment  20   a  relative to the second rockshaft section  20   b  by the operator. A set of factory installed shims  102  (shown offset from the member  72  in  FIG. 4 ) have a hook-shaped configuration with apertures  103  and are supported by bolts  106  passing through the apertures. The set of shims  102  when installed around the member  90  provides initial adjustment of the length of the member  72 . The total thickness of the set of factory installed shims  102  is selected to compensate for manufacturing tolerances and generally establishes the minimum length of the adjustable length member  72  for the desired angular adjustment range of the rockshaft segment  20   b  relative to the segment  20   a.    
         [0021]     The shims  104 , which include hook-shaped ends with access tabs  107 , are pivotally connected at the opposite ends to the hinge plate  58  by an upright pin  110 . The shims  104  pivot about the pin  110  between a storage position (upper shims  104  in  FIG. 4 ) offset from the adjustable length member  72  and a working position (lowermost shims  104  in  FIG. 4 ) wherein the hooked portion generally embraces the shaft  90  between the upper end of the cylindrical member  72  and the bottom of the bracket  74 . A spring-loaded lever  112  engages notches  114  to retain the stored shims in the storage position. The same lever  112  engages a similar notch (not shown) angularly offset from the notch  114  when the shim  104  is rotated against the adjustable length member  72  to lock the shim in the working position.  
         [0022]     To provide on-site adjustment, the operator rotates the shaft  90  to extend the adjustable length member  72  and raise the bracket  74  from the shims. The lever  112  is pulled against the bias to release the shims  104  for pivoting about the pin  110 . Once the desired number of adjusting shims  104  are pivoted away from or into position against the member  72 , the operator releases the lever  112 , and the lever engages a notch in each one of the shims  104  to lock the shims  104  in their respective working and storage positions. The operator then rotates the threaded shaft  90  to tightly sandwich the adjusting shims  104  between the factory installed pack of shims  102  and the bottom of the bracket  74  to provide the necessary member length for the desired angular adjustment between the rockshaft segments  20   a  and  20   b . The flexible rockshaft joint described above provides a strong, reliable rockshaft joint that is flexible and adjustable and ideally suited for heavy duty operation such as in a multi-section folding agricultural implement.  
         [0023]     In an alternate embodiment ( FIG. 5 ) of a flexible joint  140 , a first hinge member  150  is connected to the outer end of the rockshaft segment  20   b . An adjustment hinge member  152  is connected by a pivot  154  to the first hinge member  150  for rocking relative to the rockshaft segment  20   b  about a generally fore-and-aft extending pivot axis  156 . The hinge member  152  extends downwardly and outwardly from the pivot  154  to a connection with a slotted upright plate  158 . A parallel or second plate  160  is pivotally supported from a forward end of the first plate  158  by a pivot pin  162  for rocking about an axis  166  generally parallel to the longitudinal axis of the rockshaft segment  20   c . The innermost end of the rockshaft segment  20   c  is fixed to the outer face of the plate  160 . A bracket  168  fixed to the inner end of the rockshaft segment  20   c  parallel to the plate  160  projects rearwardly to a pivotal connection  170  with a lowermost portion of an eyebolt or adjustable length member  172 . The member  172  has an upper end threaded end  173  passing through an aperture in an outwardly projecting bracket  174  fixed to the outer face of the plate  158 . Nuts  180  and  182  are threaded onto the end  173  against opposite sides of the bracket  174  and are locked in position by lock nuts  184  and  186 . By changing the location of the nuts  180  and  182  on the threaded end  173 , the angular position of the rockshaft segment  20   b  relative to the plate  158 , and thus the relative angle between the segments  20   a  and  20   b , can be adjusted. The pivotal connection  170  includes a bolt and bushing extending through aligned apertures in the bracket  168  and the plate  160  and through a slot  186  in the plate  158 . The pivotal connection  170  and operation is similar to that described above with respect to the pivotal connection  70  of  FIG. 4 .  
         [0024]     Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims. For example, although eyebolt and trunnion arrangements are specifically shown, it is to be understood that other types of variable length or adjustment mechanisms could be utilized with the present invention including cylinders and other remotely controlled structures for making angle adjustments automatically on-the-go.