Abstract:
The present invention provides support frame for a tire assembly for irrigation systems that prevents the formation of ruts caused by repeated travel along a path by tires of a mobile vehicle or structure. The support frame includes a force transfer member connected between the support frame and the irrigation tower structure for transferring forces generated by the tire assembly to the tower structure. The support frame includes plural adjustable mounting features to accommodate a retro fit to a variety of existing units. The support frame further includes an adjustable compensation spring to adjust to forces applied to the support frame caused by uneven terrain. The support frame is adapted for use with corner sweeping units.

Description:
[0001]    This invention claims the benefit of co-pending U.S. Provisional Application No. 60/446,057, entitled “Tire Assembly Support Frame For Irrigation Systems”, filed Feb. 7, 2003, the entire disclosure of which is hereby incorporated by reference as if set forth in its entirety for all purposes. 
     
    
     
       TECHNICAL FIELD  
         [0002]    This invention relates to irrigation systems and in particular to a support frame for a tire assembly for mobile irrigation structures.  
         BACKGROUND OF THE INVENTION  
         [0003]    Irrigation systems are commonly used in agricultural operations such as, for example, large scale commercial farms. One common type of such a system is a center-pivot irrigation system which typically employs an elongate boom that is connected at one end to a center pivot which acts as a water source for the boom. Typically, the boom is comprised of a plurality of pipes connected together extending away from the center pivot with sprinklers or other watering devices located along the length of the boom to spray water across the soil. The boom is elevated and supported by a number of mobile towers with wheels for transport across the ground. One of the towers acts as a drive tower so that the boom travels in wide circles about the center pivot. Some of the center pivot systems employ a corner sweep unit for systems that are located near the corner of a plot of land. The corner sweep unit is located at the end of the boom opposite the center pivot. The corner sweep unit pivots about it&#39;s own axis as the corner sweep unit approaches the corner of the property as the boom rotates. Corner sweep units maximize the use of irrigation water in tight corners to ensure irrigation of the most amount of soil.  
           [0004]    Another common type of irrigation equipment is known as a linear system that typically uses the same type of equipment described above but that travels along a straight path instead of a circular path.  
           [0005]    The irrigation systems described above are typically repeatedly driven along their paths for a period of time to adequately irrigate the land and create very wet soil conditions over which the irrigation equipment must necessarily travel. Most current irrigation equipment systems employ tires that have a tread such as, for example, a tractor tread tire on the towers to move the system across the ground. One problem with such tires is that the tread in the tires directs water to the center of the path along which the tire travels causing further saturation of the soil creating a very muddy and soggy travel path. Because the irrigation systems are driven over the same path for long periods of time ruts eventually develop along the path. The weight of the irrigation equipment along with the soggy soil along the travel path contributes to the formation of ruts. Depending on the type of soil and how long the irrigation system travels over the same path the ruts can become several feet deep. As an example, ruts as deep as five or six feet deep are known to have been formed.  
           [0006]    These ruts cause several problems. One problem is that the tires of the tower may become stuck so that the tower is unable to continue along the path. With very deep ruts, parts of the tower itself may engage the ground and may become stuck. For example, the towers form a frame that supports the boom and the tires. The frame may include cross struts that extend between front and back members of the frame located several feet above the ground surface. Some ruts are so deep that the cross struts are at ground level and drag along the ground surface and may become stuck. Parts of the irrigation equipment may experience damage or failure. Furthermore, a tractor or other large vehicle must be utilized to pull the tower from its stuck position. This increases the time and expense of irrigation.  
           [0007]    Another problem caused by ruts is that they can damage other agricultural vehicles that travel across the field. For example, some commercial farm vehicles such as fertilizers typically travel across a crop field at a speed of about 15 mph. Some of these vehicles use a boom of between 80-100 ft. long to disperse fertilizer across the crop field. Other vehicles or equipment such as hay balers and harvesters carry heavy loads. Traveling across ruts at such speeds puts great stress on the vehicles and they may experience damage. Significant damage may occur with very deep ruts. In order to avoid damage the vehicles must slow down each time a rut is encountered. Since the vehicles are unable to travel at a constant speed production time and labor costs are increased.  
           [0008]    Yet another problem caused by ruts is erosion. Erosion is a problem encountered with many agricultural endeavors. Ruts magnify the erosion problem by providing a channel in which the irrigation water or rain water washes away topsoil. This is especially problematic on land that slopes or on farmed land located on hillsides. In some instances the washed-away soil may be recovered and hauled back to its original location. If the washed-away soil is not recoverable new soil must then be brought in and distributed over the eroded land. In addition to damage to the land such erosion causes increased expense for soil recovery and/or replacement.  
           [0009]    Some attempts to solve the problem with ruts include filling the ruts with straw, wood chips, compost, gravel, concrete or debris. This attempt has not proved to be acceptable because of land pollution and contamination issues. Successive land owners may experience damage to some equipment and may be required at great expense to clean up and remove the fill material. If contamination of the soil is an issue additional costs must be incurred to remove such contaminants.  
           [0010]    Other attempts to fill the ruts include the use of commercially available clotting pellets or other clumping material that hardens when wet. However, such products have proved to be inconsistently effective. Additionally, these products must be purchased every time a rut is formed which increases costs and requires continued maintenance.  
           [0011]    One prior art device that attempts to prevent formation of ruts utilizes a ground engaging track for the tower wheels. The track comprises flat plates or sections that are hinged together around the tire. The device has side walls that extend down the sides of the tire. The problem with such a device is that the hinges wear out which may cause damage and require repair or replacement of the device. The side walls of the device also pinch the sides of the tires causing wear and damage to the tires. Additionally, if the device encounters a rocky patch in the soil the device may get stuck or stall causing the tire to spin inside the track. Furthermore, such a device experiences vibration which loosens lug nuts on wheels and causes noise.  
           [0012]    Other attempts to prevent ruts from forming include the use of steel wheels. However, such wheels are very heavy and place a great deal of stress on the axle and/or gear box of the tower drive mechanism. Additionally, such steel wheels require a vehicle such as, for example, a front end loader to attach the steel wheel to the tower.  
         SUMMARY OF THE INVENTION  
         [0013]    The present invention provides a device for irrigation systems that prevents the formation of ruts caused by repeated travel along a path by tires of a mobile vehicle or structure. The irrigation system includes an elongate boom connected at one end to a center pivot that acts as a water source for the boom. The boom includes a plurality of pipes connected together to extend away from the center pivot with sprinklers located along the length of the boom to spray water across the soil. The boom is elevated and supported by a number of mobile towers each of which has a tire assembly for transporting the tower and, thus, the boom across the ground in wide circles about the center pivot.  
           [0014]    Each tire assembly includes dual tires mounted on an axle with a flexible belt member wrapped around the outer periphery of the two tires. The flexible belt member is preferably adapted to be wrapped around the dual tires so that an inner surface of the flexible belt member engages the outer periphery of the tires and an outer surface of the flexible belt member engages the ground. The flexible belt member includes opposed ends and means to secure the opposed ends together when mounted on the dual tires.  
           [0015]    The flexible belt member may include a plurality of spaced apart cleats located on the outer surface of the flexible belt member. The cleats provide traction as the tower moves along the path. The cleats are preferably spaced apart a distance to allow the flexible belt member to engage the ground and provide a ground engaging surface to substantially evenly distribute the weight of the tower structure across the ground to reduce ground compaction. Furthermore, the cleats direct water away from the center of the travel path to the outer sides thereof.  
           [0016]    The present invention also provides a dual tire assembly in which one tire is inflated to inflation pressure that is greater than that of the other tire. Inflating one tire to a pressure greater than the other tire prevents too much pressure or leverage from being applied to the tire assembly drive mechanism. Preferably, the inner tire or tire located toward the center pivot is inflated to about twice the pressure of the outside tire.  
           [0017]    The present invention further provides a tire assembly support frame that supports the tire assembly. The support frame substantially removes forces carried by the outer tire that would otherwise be transferred to the gear box possibly causing damage. The support frame may be connected to and supported by the tower structure on one side and is connected to the outer tire through an extended axle. The support frame includes a force transfer member connected between the support frame and the tower structure for transferring forces generated by the tire assembly to the tower structure. The support frame includes a plurality of adjustable mounting features to accommodate retrofitting to a variety of existing units. One or more compensating springs may be incorporated into the support frame to adjust to varying pressure applied to the support frame by uneven terrain. The support frame, including at least the features mentioned above, may also be adapted for use with corner sweep units.  
           [0018]    The invention is particularly effective in wet or loose soil environments created by irrigation systems and/or farming activities for large or commercial farms. Although the invention is described as being used primarily with center pivot irrigation systems, it is contemplated that the present invention not be limited to center pivot irrigation systems but may also be used with other irrigation systems such as, for example, linear irrigation systems and other mobile structures in which the formation of ruts in the ground is a problem.  
           [0019]    The foregoing is not intended to be an exhaustive list of embodiments and features of the present invention. Persons skilled in the art are capable of appreciating other embodiments and features from the following detailed description in conjunction with the drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIG. 1 is a top plan view of a simplified center pivot irrigation system utilizing mobile support structures to support an elevated boom.  
         [0021]    [0021]FIG. 2 is a partial plan view of a mobile support structure with a tire assembly of the present invention.  
         [0022]    [0022]FIG. 3 is a front view of the tire assembly of the present invention.  
         [0023]    [0023]FIG. 4 is a side view of the tire assembly of the present invention.  
         [0024]    [0024]FIG. 5 is a side view of the flexible belt in a flat condition.  
         [0025]    [0025]FIG. 6 is a sectional view along lines  6 - 6  in FIG. 7 of a support frame for the tire assembly.  
         [0026]    [0026]FIG. 7 is a front view of the support frame with the tire assembly shown in phantom.  
         [0027]    [0027]FIG. 8 is a side view of the support frame with the tire assembly and flexible belt.  
         [0028]    [0028]FIG. 9 is an enlarged partial front view of the mounting of the support frame to the tower structure.  
         [0029]    [0029]FIG. 10 is a side view of the mounting shown in FIG. 9.  
         [0030]    [0030]FIG. 11 is a front view of a support frame for a corner unit of an irrigation system.  
         [0031]    [0031]FIG. 12 is a side view of the support frame as shown in FIG. 11.  
         [0032]    [0032]FIG. 13 is a partial view showing the connection between the support assembly and the horizontal members of FIGS. 11 and 12  
         [0033]    [0033]FIG. 14 is a front view showing another embodiment of the corner sweeping unit support frame.  
         [0034]    [0034]FIG. 15 is a partial view showing the connection between the support assembly and the horizontal members of FIG. 14. 
     
    
     DETAILED DESCRIPTION  
       [0035]    Referring now to FIGS. 1 and 2, a center pivot irrigation system  10  is shown in accordance with the present invention wherein the system  10  is adapted to rotate about a center pivot  12  that serves as a water supply for an elevated boom  14 . Boom  14  is supported on a plurality of mobile support structures or towers  16 . Although these figures illustrate a center pivot irrigation system the present invention is not intended to be limited to center pivot irrigation systems. Additionally, although only one boom  14  and three mobile towers  16  are shown the present invention is not intended to be limited to the number of booms or mobile tower structures. The number of towers depends of the length of the boom which is dependent on the size of the area of land to be irrigated. For example, the span between mobile towers  16  is typically between about 130 to 140 ft. However, this length may vary.  
         [0036]    As seen in FIGS. 1 and 2, centrally located pivot structure  12  serves as a water supply to boom  14 . Boom  14  comprises a plurality of pipes  18  connected end-to-end with sprinklers  20  spaced along the length of boom  14 . Boom  14  is supported by mobile towers  16  that have ground engaging elements  22  to propel boom  14  along a travel path about central pivot  12 . Preferably, each tower  16  includes front and rear ground engaging elements  22 . Towers  16  are self-propelled by ground engaging means  22  that are driven through a gear box drive mechanism  23  in a manner known to those skilled in the art.  
         [0037]    As seen more clearly in FIGS. 2-4, each ground engaging means  22  is shown as comprising a tire assembly  24  comprising dual tires  26  and  28  mounted for rotation on a hub  30 . Hub  30  includes flanges  30   a  and  30   b  on each end having bolt holes matching the bolt hole configuration on the wheels as best seen in FIG. 4. One of the flanges  30   a  is connected to a flange  29  on an axle  31  from gearbox  23  by bolts or any other suitable connection. Hub  30  acts as an extension from gearbox  23  to accommodate mounting of dual tires  26  and  28 . FIG. 2 shows that tire assembly  24  is canted or mounted on an angle to a vertical axis. This is done to prevent the application of too much force or pressure on the axle  31  and/or gear box  23  as system  10  is driven around its travel path. For example, tires that are mounted normal to the boom  14  and supported on an axle positioned normal to tower  16  have the tendency to follow a straight path. However, the tires are forced from a straight path by the center pivot structure so that the tires travel in a circular path. This puts a great deal of stress on axle  31  and/or gear box  23  as well as causing wear on the tires. Tire assembly  24  of the present invention is capable of having a canted mounting by inflating one of the tires to a pressure of about twice that of the other tire. For example, the tire closest to the center pivot, referred to as the inner tire as seen most clearly as tire  26  in FIG. 3, may have an inflation pressure of about 28-30 psi. The other tire, referred to as the outer tire as seen most clearly as tire  28  in FIG. 3, may have an inflation pressure of about 10-12 psi. Thus, the tires  26  and  28  counteract the force from center pivot  12  tending to pull or force tires  26  and  28  toward center pivot  12 .  
         [0038]    Tire assembly  24  includes a flexible member or belt  32  wrapped around the outside of tires  26  and  28 . Belt  32  is made of a flexible material such as, for example, rubber and has a substantially flat shape before mounting on tires  26  and  28  as seen in FIG. 5. Belt  32  has a length and a width with opposed ends having a coupler  34  to connect the opposed ends of belt  32 . One example of such a coupler  34  is belt lacing that may be interwoven and secured with the opposed ends of belt  32  when it is wrapped around tires  26  and  28 . However, although only belt lacing is described as one type of coupler it is within the scope of this invention that any suitable coupler for connecting the opposed ends of belt  32  may be utilized. In order to mount belt  32  onto tires  26  and  28  they may be deflated to an inflation pressure less than that in use to facilitate mounting of belt  32  around the outer periphery of tires  26  and  28 . After belt  32  is mounted on tires  26  and  28  they are inflated to their respective inflation pressures as described above. The length and width of belt  32  may vary according to the size of tires used. For example, with 14.9×24 tires, belt  32  may have a length of about 156 inches and a width of about 30 inches. As another example, for 11.2×24 tires, belt  32  may have a length of about 139 inches with a width of about 24 inches.  
         [0039]    Belt  32  has an inner surface  36  that lies adjacent to the outer surface of tires  26  and  28  when mounted thereon. At least one and preferably a plurality of center guides  38  are mounted to inner surface  36  of belt  32 . Each center guide  38  is preferably a formed metal piece having a central protrusion  40  with flat ends  42  for connection to inner surface  36  of belt  32  by a suitable connector, such as, for example, with a strong adhesive or a fastener pin. Center guides  38  help keep belt  32  in place during use.  
         [0040]    Outer surface  44  of belt  32  includes a plurality of cleat elements  46  that substantially extend across the width of belt  32  as best seen in FIG. 3. Cleat elements  46  may be in the form of channel iron having side walls  48  extending outwardly from a base  50 . Base  50  may be secured to outer surface  44  of belt  32  by any suitable connector such as, for example, fastener pins, so that side walls  48  engage the ground to provide traction as tire assembly  24  moves along the travel path. Side walls  48  further act to direct water to the outer sides of tire assembly  24  and, thus, away from the center of the travel path. Cleat elements  46  are spaced along the length of belt  32  in a manner to allow outer surface  44  to engage the ground. In one preferred example, cleat elements  46  are spaced about 10 inches apart. Although cleat elements  46  are described as channel iron other types of cleat elements are envisioned by this invention for channeling water away from the center of the travel path, as well as for traction.  
         [0041]    Tire assembly  24  of the present invention reduces soil compaction by providing a ground engaging surface area  44  of belt  32  to distribute the weight of the irrigation equipment. As one example, some prior center pivot irrigation systems can produce a force on the ground of about 86 pounds per square inch depending on the size of the tire. Using tires of comparable size, tire assembly  24  of the present invention produces a force of only about 26 pounds per square inch on the ground. Thus, the reduction of soil compaction substantially reduces the formation of ruts in the ground. Additionally, directing water away from the center of the travel path by cleat elements  46  further reduces the formation of ruts in the ground.  
         [0042]    [0042]FIGS. 6-8 show a support frame  60  for tire assembly  24 . Support frame  60  is removably connected to and supported by horizontal tube member  62  of tower  16  by a force transferring support plate  64 . Support plate  64  may be welded or otherwise secured to an attachment plate  66  to which gear box  23  is secured through outer plate  65  by bolts or fasteners  67 . Tire assembly  24  may be supported by horizontal support members  68  and  72  and a vertical support  74 . Preferably, horizontal members  68  and  72  may have a telescoping connection and may be secured by a bolt  75  or other suitable fastener. This telescoping connection provides for horizontal adjustment of support frame  60  to accommodate various sizes of tires. In the embodiment shown in FIG. 7, member  68  telescopically receives member  72  and may be welded or otherwise secured substantially centrally to attachment plate  66 . A strengthening element  70  may be welded or otherwise secured to both attachment plate  66  and member  68  to add support for member  68  and strength to plate  66 . Vertical support  74  extends down from member  72  and may be connected thereto through an adjustable telescoping connection. Preferably, vertical support  74  may be telescopically received within a tube member  78  connected to member  72  through a plate  80  that may be welded or otherwise secured thereto. At least one and preferably two strengthening gussets  81  may be welded or otherwise fastened to secure tube member  78  and plate  80  to member  72 . In order to provide further adjustment, a spring  83  extends between vertical support  74  and a bearing plate  84 . An adjustment member such as, for example, a bolt  85  extends through a plate  80  and bears against bearing plate  84  to adjust the amount of force or pressure applied to the ground. Spring  83  provides that pressure is carried as evenly as possible on both sides of support frame  60 . For example, on flat terrain pressure is distributed substantially evenly across support frame  60 . However, if the terrain is uneven and is pitched higher on one side the pressure applied to that side of support frame is increased. Therefore, spring  83  substantially compensates for unevenness in the terrain and can be adjusted to match the terrain across which tire assembly  24  travels. Vertical support  74  supports an extended axle  76  of tire assembly  24  through plate  86 . Plate  86  may be welded or otherwise secured to vertical support  74 . A bearing  82  rotatably supports extended axle  76  and may be adjustably connected to plate  86  by bolts  88  or other suitable connectors extending through elongated bolt holes  89  in plate  86 . This adjustability feature allows support frame  60  to be retrofit to a variety of tire assemblies  24 . For simplicity, FIGS. 6 and 7 do not show belt  32  on tire assembly  24 . However, it is understood that belt  32  may be used with tire assembly  24  in all embodiments of this invention.  
         [0043]    [0043]FIGS. 9 and 10 show a preferred adjustable connection between horizontal tube member  62  and support plate  64 . A bracket or vertical plate  90  may be welded or otherwise secured to horizontal tube member  62 . Support plate  64  may be removably connected to bracket  90  by bolts  92  or any other suitable fasteners extending through elongated holes  94  in support plate  64 . Horizontal tube members  62  may vary in diameter. Elongated holes  94  provide adjustment so that support plate  64  may be connected to horizontal tube members  62  regardless of its diameter. Thus, as can be seen in FIGS. 6-10, support frame  60  substantially transfers forces to horizontal tube member  62  that would otherwise be applied to gear box  23  through tire assembly  24 .  
         [0044]    [0044]FIGS. 11-13 show another embodiment of this invention in which a support frame  100  is utilized in a corner sweep unit  102  of an irrigation system. Corner sweep unit  102  includes tire assembly  24  driven through gear box  23  as shown and described above. Corner sweep unit  102  may include a swivel support tube  104  that is telescopically received in a drive tube (not shown) so that corner sweep unit  102  rotates or is driven about swivel support tube  104  as is known in the art. Swivel support tube  104  may be connected to a frame assembly  106  that supports gear box  23  through bolts  108  or other suitable fastener. Frame assembly  106  may include opposed members  106   a  and  106   b  secured together preferably by welding to a connector plate  106   c  as seen most clearly in FIG. 13. For clarity, swivel support tube  104  has been omitted from FIG. 13. Tire assembly  24  is supported on the opposite side by opposed vertical members  110  and associated horizontal members  112 . Tire assembly  24  may be connected to vertical members  110  through extended axle  76  rotatably supported by bearing  84 . Bearing  84  may be adjustably connected to vertical members  110  through a plate  114  that extends between and may be welded or otherwise secured to vertical members  110 . Plate  114  includes elongated holes  116  through which bolts  118  or other fasteners extend. This adjustability feature allows support frame  100  to be retrofit to a variety of tire assemblies. Vertical members  110  may preferably be connected to horizontal members  112  in a manner similar to that as shown and described in FIG. 7. More specifically, each vertical member  110  may be telescopically received in a female member  113  secured to a horizontal member  112  and strengthened by a gusset  115 . A spring  120  may extend between vertical support  110  and a bearing plate  122 . An adjustment member such as, for example, a bolt  124  may extend through plate  117  to bear against bearing plate  122  to adjust the amount of force or pressure applied to the ground. As described above, spring  120  provides that pressure is carried as evenly as possible on both sides of support frame  100  as the corner sweep unit  102  travels over uneven terrain. To strengthen and support vertical members  110 , plate  117  extends between opposed vertical members  110  and opposed horizontal members  112  and may be welded or otherwise secured to vertical members  110  and horizontal members  112  as most clearly seen in FIG. 12. Additionally, a further strengthening member  119  is secured such as, for example, by welding between vertical members  110 . Horizontal members  112  may be telescopically received in members  106   a  and  106   b  of frame assembly  106  and secured thereto by any suitable type of fastener  128 . This telescopic connection allows for adjustment to accommodate tire assemblies of different widths.  
         [0045]    [0045]FIGS. 14 and 15 show an alternative support frame  101  in which gear box  23  is supported by a vertical member  130  and a horizontal member  132  welded or otherwise secured thereto and strengthened by at least one gusset  133 . In this embodiment, horizontal members  112  may be telescopically received in opposed female members  134  that have been welded or otherwise secured to each side to horizontal member  132  as best seen in FIG. 15. For simplicity, swivel support tube  104  has been omitted from FIG. 15. Horizontal members  112  may be secured to associated members  134  by any suitable type of fastener  128 . This telescopic connection allows for adjustment to accommodate tire assemblies of different widths. For simplicity, FIGS. 11-13 are shown with belt  32 . However, it is understood that belt  32  may be used with tire assembly in these embodiments.  
         [0046]    Persons skilled in the art will recognize that many modifications and variations are possible in the details, materials, and arrangements of the parts and actions which have been described and illustrated in order to explain the nature of this invention and that such modifications and variations do not depart from the spirit and scope of the teachings and claims contained therein.