Abstract:
A selectively fillable ballast water tank is secured to the main frame of the drive units of a self-propelled irrigation machine. The water tank is selectively filled with water from the water pipeline when the system is going to remain stationary for a period of time, thereby reducing the risk that the drive unit will overturn when experiencing a high wind situation. The ballast water tanks are drained when the system is going to be used to irrigate.

Description:
FIELD OF THE INVENTION 
   This invention relates to a self-propelled irrigation machine or system and more particularly to a method and means for preventing the system from overturning in a high wind situation. Even more particularly, this invention prevents the system from overturning in a high wind situation by mounting a water tank on at least some, if not all, the drive units. The water tanks are filled with water for ballast when the system is not in operation. The water tanks are drained when the system is going to irrigate. 
   DESCRIPTION OF THE RELATED ART   
   Some irrigation systems or machines such as center pivot systems, lateral move systems and corner irrigation systems have a tendency to overturn or “tip over” when subjected to high winds. The overturning of the systems is at least partially due to the fact that the systems are top-heavy since the water pipeline or boom is positioned several feet above the main frame of the drive units. 
   SUMMARY OF THE INVENTION 
   A method and means for preventing a self-propelled irrigation system from overturning when subjected to a high wind condition is disclosed. Self-propelled irrigation systems such as lateral move irrigation systems and center pivot irrigation systems include an elongated water pipeline which is supported along its length by a plurality of spaced-apart drive units or towers. A ballast water tank is preferably mounted on all the drive units of the irrigation systems. A water conduit extends from the water pipeline to the ballast water tank and an electrically operated and remotely controlled switch is imposed in the conduit to enable water from the pipeline to be introduced into the ballast water tank when the irrigation system is not being used to irrigate. The tank is also provided with a discharge opening or drain opening which is also selectively opened and closed by means of an electric switch which is also remotely controlled. When the irrigation system is to remain stationary for a period of time during non-irrigating periods, the ballast water tanks are filled with water and the weight thereof acts as a ballast to prevent the system from overturning when subjected to high winds. When the system is going to be used to irrigate, the ballast water tanks are drained to reduce the weight thereof and to reduce stress on the drive unit. 
   It is therefore a principal object of the invention to provide a method and means for preventing a self-propelled irrigation system from overturning in a high wind situation. 
   Another object of the invention is to provide a means for preventing a self-propelled irrigation system from overturning in a high wind situation by mounting a ballast water tank on at least some of the drive units of the irrigation system, and preferably all of the drive units, with the ballast water tanks being selectively filled with water from the pipeline. 
   Still another object of the invention is to provide a means for preventing a self-propelled irrigation system from overturning which may be installed on the self-propelled irrigation system without extensive modification thereof. 
   These and other objects will be apparent to those skilled in the art. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a partial perspective view of a self-propelled irrigation system having the invention mounted on the drive units thereof; 
       FIG. 2  is an end view of the invention mounted on a drive unit; and 
       FIG. 3  is a side view of the invention mounted on a drive unit. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The numeral  10  refers to a conventional center pivot irrigation system which is conventional in design except for the means of this invention which is designed to prevent the overturning of the system during periods of high wind. Center pivot irrigation machine  10  is commonly referred to as a self-propelled irrigation system. Another type of self-propelled irrigation system is what is termed a lateral move irrigation system. The invention disclosed herein will work equally as well on center pivots as on lateral move systems. Further, the means of this invention will also work on irrigation systems which are described as corner pivot irrigation machines which are center pivot irrigation machines having a swing arm assembly mounted at the outer end thereof. 
   If a corner pivot irrigation system or a center pivot irrigation system is being utilized, the system  10  will include a center pivot structure  12  having a water conduit or pipeline  14  supported upon a plurality of drive units or towers  16 . Lateral move irrigation systems do not utilize a center pivot structure but simply travel across a field rather than rotating around a center pivot structure as does a center pivot irrigation system. Each of the drive units  16  includes a main frame  18  having drive wheels  20  and  22  mounted at the opposite ends thereof. A support frame  24  interconnects the main frame  18  with the pipeline  14 . Normally, the support frame  24  includes a pair of support members  26  and  28  which are secured to one end of the main frame  18  and which extend upwardly and inwardly therefrom in a diverging fashion with the upper ends thereof being connected to the pipeline  14 . Similarly, support frame  24  includes a pair of support members identical to support members  26  and  28  which are secured at their lower ends to the other end of main frame  18  and which extend upwardly and inwardly therefrom in a diverging relationship towards the pipeline  14  with the upper ends thereof being secured to the pipeline  14 . 
   The numeral  30  refers to a ballast water tank which is mounted on at least some of the drive units  16 , and preferably on all of the drive units  16  so as to prevent the overturning of the system when the system is subjected to high winds. For purposes of description, tank  30  will be described as having an upper end  32 , lower end  34 , inner side wall  36 , outer side wall  38 , and opposite end walls  40  and  42 . The lower end of the tank  30  is operatively secured to and supported upon the main frame  18  and is also preferably secured to the support frame  24  by any convenient means. When the ballast water tank  30  is viewed from either its inner or outer side, the water tank  30  defines a generally triangular shape ( FIG. 2 ). When the ballast water tank is viewed from either of its end walls, the tank generally defines an inverted triangle shape ( FIG. 3 ). As seen in  FIG. 3 , the width of the tank  30  is greater at its upper end than at its lower end so that when the tank is filled with water for ballast, the increased width at the top of the tank will allow for freezing of the water without rupturing the tank. 
   Water conduit  44  is connected to the pipeline  14  and extends downwardly to the tank  30  so that water from the pipeline  14  may be introduced into the interior of the tank as desired. For that purpose, an electrically operated and remotely controlled valve  46  is imposed in the conduit  44 . Tank  30  is provided with a discharge opening or drain opening  48  which is selectively closed and opened by means of an electrically operated valve  50  which is also remotely controllable. The valves  46  and  50  could be hydraulically controllable if so desired. 
   Normally, when the irrigation system is being used to irrigate, the ballast tanks  30  will be empty. If the system is going to be shut down for a period of time, the valves  46  are remotely opened and the valves  50  are remotely closed. Water from within the pipeline  14  fills the tanks  30  and the weight of the tanks and the water therein acts as a ballast for the drive units so that the system will not overturn in a high wind situation. The increased width of the tank at its upper end, as described above, prevents the tank from rupturing should the water in the tank freeze. When the tanks  30  are filled, valves  46  are closed. 
   When the system is going to be used to again irrigate, the valves  50  are remotely opened so that the water in the tanks  30  will be discharged therefrom to reduce the weight on the drive unit. During the draining of the tanks  30 , the valves  46  are obviously closed to prevent further water from entering the tanks from the water pipeline. 
   Although it is preferred that the tanks  30  be filled from the pipeline  14 , a separate water line could be extended along the length of the system for filling the tanks. 
   Thus it can be seen that a novel method and means has been provided for preventing an irrigation system such as a center pivot irrigation system, a lateral move irrigation system or a corner pivot irrigation system from overturning in high wind situations. 
   Thus it can be seen that the invention accomplishes at least all of its stated objectives.