Abstract:
A tower and wheel arm assembly for an implement frame includes a pair of identical single piece pivot castings which are selectively connectible at different locations along the frame and provide both wheel arm pivoting and a cylinder anchor tower pivoting. The wheel arm axle extends between the castings pivots within cylindrical cavities located in the castings. External cylindrical surfaces concentric with the cavities rotatably support a pair of tower plates which include circular openings received over the external cylindrical surfaces. Casting symmetry allows the same part to be used interchangeably for either the right-hand or left-hand support.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to lift assemblies for implement frames and, more specifically, to a lift wheel arm tower bearing assembly. 
     BACKGROUND OF THE INVENTION 
     Multi-section frames for agricultural implements such as field cultivators or similar soil working implements typically include a main frame and wing sections hinged to opposite sides of the main frame. Wheel assemblies including a wheel arm pivotally connected to frame-mounted axle support the frame sections and provide lift functions for moving the implement between a raised transport position and a lowered field-working position. The wheel assemblies can also function to provide adjustable depth control for the soil-engaging tools on the frame. 
     In some wheel assemblies, particularly those that support the wing sections, a cylinder anchor tower is pivotally connected to the wheel arm axle for pivoting about the same axis as the wheel arm. The upper end of the tower is connected to one end of an adjustable length linkage, and the opposite end of the linkage is connected to the frame to secure the tower at the desired angle. A cylinder is connected between the wheel arm and the tower. By adjusting the length of the linkage, the wheel assembly position relative to the frame can be changed for leveling frame. 
     Most previously available wheel arm support and tower assemblies are fairly complex and utilize numerous components. Frictional contact resulting from relative rotation between the tower and the wheel axle each time the wheel arm is moved to raise or lower the implement results in considerable wear. The tower requires expensive welded pivot collars or a casting with a pivot which makes the component heavy and difficult to install and to disassemble. Present support and tower construction is heavy, and convenient positioning of the wheel assembly to a location best optimizing the earthworking tool pattern often is not possible. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide an improved tower and wheel arm assembly for an implement. It is another object to provide such an assembly which overcomes most or all of the aforementioned problems. 
     It is also another object of the present invention to provide an improved tower and wheel arm assembly which is simpler and less expensive than at least most previously available assemblies. It is a further object to provide such an assembly having fewer components than most assemblies. 
     It is yet another object of the present invention to provide an improved tower and wheel arm assembly having an improved bearing arrangement. It is another object to provide such an assembly wherein the tower does not require special bearings or pivot collars and is less subject to wear than at least most previously available towers. It is a further object to provide an assembly wherein lubricated tower bearings are obviated. 
     A tower and wheel arm assembly includes a pair of single piece pivot castings which are selectively connectable at different locations along the frame and provide both wheel arm pivoting and cylinder anchor tower pivoting. The wheel arm axle extends between the castings and pivots within cylindrical cavities located in the castings. External cylindrical surfaces concentric with the cavities rotatably support a pair of tower plates which include circular openings received over the external cylindrical surfaces. 
     The dual pivoting function of the one-piece castings provides a simple and relatively inexpensive support arrangement for the wheel arm and tower and eliminates frictional wear between the tower and the axle which otherwise normally occurs when the wheel arm is pivoted to raise and lower the implement. Tower bearing lubrication is not required. Symmetrical casting configuration allows use of the same part for either the right-hand or left-hand support. Simple plate towers which are light in weight may be utilized. A compact, sturdy bearing structure is provided that is easy to connect at various locations along the frame. Assembly and disassembly of the structure is relatively fast and easy. Compared to at least most previously available support and tower constructions, the present assembly is generally lighter and provides more convenient positioning of the assembly for optimizing the tool pattern. 
    
    
     These and other objects, features and advantages of the invention will become apparent from the description below in view of the drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a multi-section implement with tower and wheel arm assembly structure attached, with some parts removed for clarity. 
     FIG. 2 is an enlarged front perspective view of the tower and wheel arm assembly structure of FIG.  1 . 
     FIG. 3 is an enlarged rear perspective view of a portion of the structure of FIG.  2 . 
     FIG. 4 is an enlarged side perspective view of the casting utilized with the structure of FIG.  2   
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, therein is shown an agricultural implement such as a field cultivator  10  having a main frame  12  supported by lift wheel assemblies  14  and  16  pivotally connected to the frame  12 . A hitch assembly  18  is pivotally connected to the forward portion of the frame  12  for connection to a tractor for forward movement (F) over the ground. The lift wheel modules or assemblies  14  and  16  are connected to a hydraulically operated lift linkage assembly indicated generally at  20  for pivoting the assemblies  14  and  16  to move the implement vertically. Outer frame or wing sections  24  and  26  are hinged to opposite sides of the main frame  12  for pivoting between a folded transport position and an extended working position (shown) by wing fold cylinder structure indicated generally  30 . Earthworking tools  32  are supported by the frame  12  and wing sections  24  and  26 . Some tools have been removed in FIG. 1 for clarity and to better show the wheel assemblies. 
     Wing lift wheel arm and tower assemblies  34  and  36  are connected at selectable locations on the wing frames  24  and  26  to adjustably support the frames. The assemblies  34  and  36  include lift cylinders  44  and  46  which operate generally in unison with cylinders  48  and  50  of the lift linkage assembly  20  to raise and lower the frames  24  and  26  with the main frame  12 . A more detailed description of the frame shown in FIG. 1 may be found in our copending and commonly assigned patent application Ser. No. 10/326,672 filed Dec. 19, 2002 entitled IMPLEMENT LIFT AND LEVEL SYSTEM WITH A FRONT MOUNTED DIRECT COUPLED ROCKSHAFT. However, it is to be understood that the frame structure is given by way of example only and that assemblies  34  and  36  may be utilized with other types of frames. 
     Referring now to FIGS. 2-4, the wheel arm and tower assembly  36  will be described in detail. The construction of the assembly  36  is generally identical to that of the assembly  34 . The assembly  36  includes a pair of identical reversible pivot bearing castings or brackets  54  and  56  connected to a transverse tube  26 t of rectangular cross section forming a portion of the wing frame  26 . The castings  54  and  56  pivotally support a wheel arm  58  and a tower  60 , each individually rotatable about an axis  62  which extends transversely to the forward direction F. An adjustable length link  66  is connected between the upper end of the tower  60  and a bracket  68  connected to a forward rank or frame member  70  (FIG. 1) of the implement frame. The cylinder  46  includes a base end connected to the tower  60  between the axis  62  and the link  66 . The rod end of the cylinder  46  is connected to a lower wheel arm bracket  72  which also supports a walking beam wheel assembly  74 . Cylinder extension and retraction raises and lowers the wing frame  26 , while adjusting the length of the link  66  changes the position of the base end of the cylinder  46  to adjust wheel position for a given cylinder rod extension or retraction for leveling the implement and providing working depth adjustment for the tools on the wing frame. 
     The brackets  54  and  56  are generally identical and are shown as a unitary casting. A mounting area  80  (FIG. 4) includes faces  82  and  84  formed at a right angle to each other to abut adjacent bottom and forward faces of the supporting frame member. Apertures  86  and  88  receive threaded legs of U-bolts  90  which extend around the remaining faces of the frame member. Nuts  92  are threaded on the legs to secure the casting firmly against the frame member. Peripheral reinforcing ribs  94  and  96  extend downwardly and forwardly from the mounting area  80  to a cylindrical bearing cavity area  100 . The cavity area  100  includes axle bearing surface structure  102  with a central annular lubrication groove  104  in communication with a lubrication channel  106  located in a grease zerk receiving projection  108 . The projection  108  is located to optimize tool clearance. The end of the cavity area  100  is closed at a side  110  to protect the area from contamination. A cylindrical mast support bearing or shoulder  112  projects axially from the open side of the cavity area  100  and includes a fixed cylindrical bearing surface  114  centered on the axis  62 . A cylindrical axle or wheel arm pivot  118  is fixed to the wheel arm  58  and includes opposite ends inserted into the cavity areas  100  and supported for rotation about the axis  62  within the bearing surfaces  102 . The tower  60  is supported on the fixed bearing surfaces  114  of a pair of the brackets  54 ,  56  for rotation about the axis  62  as the length of the link  66  is adjusted. 
     As shown, the tower  60  is fabricated from a pair of generally identical upright, transversely spaced plates  124  and  126  having lower ends with apertures  128  received over the bearing surfaces  114 . The plates  124  and  126  extend upwardly to cylinder base end mounting areas  130  which receive a pivot pin and spacer assembly  132  for pivotally connecting the base end of the cylinder  46  between the plates  124  and  126  and for maintaining proper spacing between the plates at the cylinder mounting areas. The plates  124  and  126  extend upwardly to a link mounting areas  140  located forwardly and above the cylinder mounting areas  130 . A link pivot pin and spacer assembly  142  is supported in apertures in the link mounting areas for pivotally connecting the aft end of the link  66  to the upper end of the tower and for maintaining the proper spacing between the upper ends of the plates  124  and  126 . A spacer assembly  146  extends between the lower ends of the plates  124  and  126 . 
     The spacer assemblies  132 ,  142  and  146  maintain the plates  124  and  126  in a parallel relationship. The brackets  54  and  56  are mounted on the frame so that the bearing surfaces  102  and  114  are spaced for good support of the axle  118  and the tower  60 . For assembly, the pivot bearing castings  54  and  56  can be located on the desired frame member at a location best suited for the tool pattern to avoid interference. Initially, the castings  54  and  56  are loosely mounted on the frame, and the axle  118  and the tower  60  are positioned relative to the castings. Thereafter, the castings  54  and  56  are slid towards each other to capture the axle  118  and the tower  60 . The nuts  92  are then tightened onto the threaded ends of the bolts  90  to secure the castings in position. The assemblies  34  and  36  can be disassembled by simply loosening one or both of the castings and sliding the castings apart. The entire assembly can be easily adjusted transversely on the frame member or moved to a different mounting location. Relative rotation between the tower  60  and the tower support bearing surfaces  114  only occurs when adjustments are made to the wheel position by changing the length of the link  66 , and therefore lubrication is not required at the surfaces  114 . The symmetry of the brackets  54  and  56  about a transversely extending plane bisecting each bracket and lying on the axis  62  (see FIG. 4) permits the bracket to be positioned with the cavity area  100  opening either to the left or to the right so that a single casting configuration can be used for both brackets to reduce parts numbers and decrease manufacturing costs. 
     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.