Abstract:
A flotation drive assembly for mechanized irrigation systems such as a corner pivot irrigation machine, a center pivot irrigation machine or a linear move irrigation machine wherein the flotation drive assembly improves upon the field traction of the mechanized agricultural irrigational systems and which improves the resistance to wheel track rutting that may occur during the normal operation of the systems. The flotation drive assembly of this invention is designed so that the gearbox which drives the wheel/tire assemblies at the opposite ends of the main frame of the drive unit or tower is mounted so as not to support the weight of the tower or the water contained therein.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a drive assembly for mechanized irrigation systems and more particularly to a flotation drive assembly for a mechanized irrigation system such as a corner pivot irrigation system, a center pivot irrigation system, or a linear move irrigation system. More particularly, this invention relates to a flotation drive assembly for mechanized irrigation systems which improves the field traction of the systems and which improves the resistance to wheel track rutting that may occur during the normal operation of the irrigation system. Even more particularly, this invention relates to a flotation drive assembly for mechanized irrigation systems wherein the gearboxes associated therewith do not support the weight of the system. 
     2. Description of the Related Art 
     Mechanized agricultural irrigation systems such as a corner pivot irrigation system, a center pivot irrigation system or a linear move irrigation system typically include a water delivery pipeline which is supported by a plurality of structural steel towers or drive units. The towers or drive units usually have at least two wheel/tire assemblies associated therewith which contact the ground and support a substantial percentage of the total weight of the system. The wheel/tire assemblies are usually mounted to a gearbox, which itself is mounted to the tower. The gearbox therefore experiences a significant overhung load due to the cantilevered arrangement of the wheel/tire assembly. When this setup is used with a wheel/tire assembly of a larger than average width, the overhung load becomes too large for current gearboxes to withstand and they eventually fail. 
     The need for a wider than normal traction contact patch arises from the significant rutting and traction problems that occur mainly in potato and sugar beet fields, however these problems do occur in other field situations as well. Past trials with gearbox arrangements using wider than average, or flotation, wheel/tire combinations have demonstrated large forces on the gearbox which have resulted in output shaft, flange, bearing and mounting failures. Such issues must be addressed before any flotation options may be utilized. 
     SUMMARY OF THE INVENTION 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key aspects or essential aspects of the claimed subject matter. Moreover, this Summary is not intended for use as an aid in determining the scope of the claimed subject matter. 
     A flotation drive assembly for mechanized irrigation systems such as corner irrigation systems, center pivot irrigation systems or linear move irrigation systems. In all of the irrigation systems described above, a water pipeline is supported upon a plurality of spaced-apart drive towers or drive units. In the instant invention, a pair of wheel/tire assemblies are rotatably geared to the towers for driving the towers and the water pipeline over the area to be irrigated. A pair of spaced-apart support frames are secured to the associated drive tower with the support frames having first and second sides. A wheel/tire assembly is rotatably secured to each of the support frames so as to be positioned at one side of the associated support frame. Each of the wheel/tire assemblies include a drive axle. A motor driven gearbox is secured to each of the support frames so as to be positioned at the other side of the associated support frame in a cantilevered manner. Each of the motor driven gearboxes are operatively connected to the drive axle of the associated wheel/tire assembly to rotate the same without the associated gearbox supporting the weight of the associated drive tower. 
     It is therefore a principal object of the invention to provide an improved flotation drive assembly for mechanized irrigation systems such as corner pivot irrigation systems, center pivot irrigation systems and linear move irrigation systems. 
     A further object of the invention is to provide an improved mounting means which enables the utilization of wide flotation wheel/tire combinations on existing irrigation drive towers or drive units. 
     A further object of the invention is to provide a flotation drive assembly for mechanized irrigation systems wherein the gearbox for the drive wheels thereof are mounted outside the structure of the drive unit or tower and which does not support the weight of the steel tower structure or the water contained therein. 
     It is a further object of the invention to provide a flotation drive assembly for mechanized irrigation systems which improves the field traction of the irrigation system and which improves the resistance to wheel track rutting that may occur during the normal operation of the irrigation system. 
     Still another object of the invention is to provide a flotation drive assembly for mechanized irrigation systems which allows the use of wide flotation wheel/tire combinations with little or no additional wear on the gearbox or tower itself. 
     These and other objects will be apparent to those skilled in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
         FIG. 1  is a perspective view of a corner irrigation system having the flotation drive assembly of this invention mounted on the drive wheels of the corner tower; 
         FIG. 2  is a perspective view of the tower for the corner irrigation system of  FIG. 1  having the flotation drive assemblies of this invention mounted thereon; 
         FIG. 3  is a perspective view of one of the flotation drive assemblies mounted on a pair of dual wheels; 
         FIG. 4  is a side view of the assembly of  FIG. 3 ; 
         FIG. 5  is an end view of the assembly of  FIG. 3 ; 
         FIG. 6  is a side view of the assembly of  FIG. 3 ; 
         FIG. 7  is an exploded perspective view of the drive assembly of this invention and its related structure on a corner irrigation system; 
         FIG. 8  is an exploded perspective view of the flotation drive assembly of this invention as utilized with a corner irrigation system; 
         FIG. 9  is a further exploded perspective view of the structure of  FIG. 8 ; and 
         FIG. 10  is a side exploded view of the structure of  FIG. 8 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Embodiments are described more fully below with reference to the accompanying figures, which form a part hereof and show, by way of illustration, specific exemplary embodiments. These embodiments are disclosed in sufficient detail to enable those skilled in the art to practice the invention. However, embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. The following detailed description is, therefore, not to be taken in a limiting sense in that the scope of the present invention is defined only by the appended claims. 
     The flotation drive assembly of this invention is referred to by the reference numeral  8  and is designed to be used with a mechanized or mobile irrigation system such as the system  10  ( FIG. 1 ) which is commonly referred to as a corner pivot irrigation system. The assembly  8  of this invention may also be used on a center pivot irrigation system or a linear irrigation system. The assembly  8  may be mounted on some or all of the drive towers of the irrigation system. In  FIG. 1 , the system  10  includes a center pivot structure  12  having a main arm  14  extending outwardly therefrom. The main arm comprises a water conduit or pipeline  16  supported upon a plurality of non-steerable drive towers  18 . Corner arm  20  is pivotally connected to the outer end of main arm  14  at  22  in conventional fashion and comprises a water conduit or pipe  24  which is supported upon a steerable drive tower  26  in conventional fashion. 
     As seen, the steerable drive tower  26  includes a main beam  28  having opposite ends. The beam  28  may be disposed at a right angle to the longitudinal axis of the pipe  24  or at some other angle with respect thereto as is common in most corner pivot irrigation machines. A pair of tubular supports  30  and  32  are secured to the opposite ends of main beam  28  with the lower ends thereof rotatably receiving vertically disposed pipes  34  and  36  therein respectively, such as disclosed in U.S. Pat. No. 6,039,273. The pipes  34  and  36  are connected together and are rotated in unison by a steering mechanism  37  of conventional construction. 
     An assembly  8  is secured to the lower ends of each of pipes  34  and  36 . Inasmuch as the assemblies are identical, only one of the assemblies  8  will be shown and described in detail. The numeral  38  refers to an inverted L-shaped support having an upper leg  40  and a lower leg  42 . The free end of leg  40  is welded to the lower end of pipe  38  for rotation therewith. The lower end of leg  42  is provided with an opening  44  formed therein ( FIG. 8 ). 
     The numeral  46  refers to a support frame having a generally vertically disposed wall  48 , a generally horizontally disposed bottom wall  50  and side walls  52  and  54 . The lower end of wall  48  is provided with an opening  56  formed therein ( FIG. 8 ). Frame  46  also includes a hollow tube  58 , one end of which is welded to one side of wall  48 , the interior of which communicates with opening  56 . Preferably, the inner end of tube  58  is received by a supporting hub  60  which is also welded to wall  48 . The numeral  62  refers to a tubular sleeve bearing which is adapted to be slidably mounted on tube  58  as will be described in more detail hereinafter. The numeral  64  refers to a drive shaft assembly including an outer tube or pipe  66  which has the drive shaft  68  received therein in a fixed manner and which extends therefrom. A pair of spaced-apart circular flanges  70  and  72  are welded to tube  66  and have radially spaced bolt openings  73  formed therein which are adapted to receive bolts therein to secure the tire/wheel assemblies  74  and  76  thereto. The numeral  78  refers to a safety cap. The outer end of drive shaft  68  is tapped at  80  ( FIG. 9 ) so as to receive a bolt therein which extends through cap  78  to secure cap  78  to drive shaft  68  so as to be positioned adjacent the outer end of tube  66 . 
     To assemble the parts just described, the preferred manner of assembly is to first slip sleeve bearing  62  onto tube  58  as far as possible. Once sleeve bearing  62  has been mounted on tube  58 , the drive shaft assembly  64  is slid onto sleeve bearing  62  with the drive shaft  68  being received by sleeve bearing  62  and tube  58  so that the end of drive shaft  68  extends opening  56  in wall  48  and through opening  44  in portion  42  of support  38 . After the drive shaft  68  has been inserted as far at it will go, the safety cap  78  is secured to the end of shaft  68 . 
     A spherical bearing  81  is then slid onto the protruding end of the drive shaft  68  and slid onto the frame  46 . A rigid shaft coupler  82  is then slid onto the drive shaft  68  with a shaft key and attached to the drive shaft with set screws. A gearbox mounting plate  84  is then secured to the gearbox  86  with the gearbox output shaft  88  then being inserted into the rigid shaft coupler  82 . The set screws in the coupler  82  are then tightened, and gearbox mounting plate bolts are then utilized to attach the gearbox mounting plate  84  to the frame  46 . 
     Depending upon the arrangement of the wheel/tire combination, the wheel/tire(s) may need to be installed at a certain point in the steps listed above. This does not, however, affect the order in which the other components will be installed relative to each other. The steps described above may be different if the structure is installed on a tower different than that of a corner pivot irrigation machine. The general layout and quantities of the components will remain the same though, as the concept is adaptable to different varieties of mechanized irrigation drive unit towers. 
     It can be seen that the unique structure described above enables the gearbox  86  to be secured to the drive shaft  68  by way of the rigid coupler  82  which transmits all torque created by the gearbox in an efficient manner. In the arrangement described above, the gearbox  86  is mounted outside the structure of the tower and does not support the weight of the drive tower or the water contained in the pipeline. All reaction forces are transferred into the tower by way of the sleeve bearing  62  and drive shaft assembly  64 . This permits the use of wide flotation wheel and tire combination with little or no additional wear on the gearbox or tower itself. 
     It can therefore be seen that the invention accomplishes at least all of the stated objectives. 
     Although the invention has been described in language that is specific to certain structures and methodological steps, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific structures and/or steps described. Rather, the specific aspects and steps are described as forms of implementing the claimed invention. Since many embodiments of the invention can be practiced without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.