Self-propelled irrigation system with articulated drive tower

A self-propelled irrigation system has an elongated pipeline supported above a field by a plurality of drive towers. The drive towers each have a base beam assembly, a tower structure extending above the base beam assembly for supporting the elongated pipeline, and a plurality of drive wheel assemblies for moving the base beam assembly over a field. The drive assemblies include first and second drive assemblies mounted to respective ends of the base beam assembly. At least one of the drive towers also has a third drive assembly mounted to the base beam assembly between the first and second drive assemblies. The base beam assembly supporting the third drive assembly is articulated between its first and second ends and pivotally connected to the lower ends of the tower structure to allow the third drive assembly to move vertically relative to the first and second drive assemblies when traversing uneven terrain.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to self-propelled irrigation systems and, in particular, to a drive unit for a tower of a self-propelled irrigation system that provides improved traction and flotation as the sprinkler traverses a field.

2. Description of the Related Art

Self-propelled irrigation systems are used to provide water for agricultural purposes in arid regions. Typically, such systems include a series of spaced drive towers connected by truss sections that support an elongated water distribution pipeline between the towers. In center pivot systems, the water distribution pipe extends radially from a central pivot connected to a water supply. In linear move irrigation systems, the water distribution pipe extends laterally from a canal feed or hose drag system that provides the water supply.

Water passing through the distribution pipeline is forced out through a number of sprinkler heads, spray guns, drop nozzles, or the like spaced along the length of the pipe. Each drive tower in the system is supported on wheels or other structures that are driven at slow speeds to move the tower in a circular path about the central pivot, or a linear path in the case of linear move systems, to thereby irrigate a large tract of land.

Conventional drive towers for self-propelled irrigation systems are each supported by an elongated base beam that extends transverse to the water pipeline with a drive wheel at each end of the base beam. The weight of the drive tower and the corresponding part of the water pipeline is approximately evenly distributed between the two drive wheels. However, in difficult terrain these two-wheeled drive towers sometimes become stuck or leave deep ruts in the field, which are undesirable.

There have been many attempts in the prior art to improve the flotation and traction of conventional drive towers for self-propelled irrigation systems. For example, there have been three-wheeled drive towers in which all three wheel assemblies are mounted to a rigid base beam. However, these drive towers do not maintain a constant weight distribution among the three wheels and often have one wheel come off the ground when the system traverses uneven terrain.

Additional attempts to improve drive towers are described in U.S. Pat. No. 6,131,833 issued to Chapman (tracked drive tower), and U.S. Pat. No. 7,229,032 issued to Christensen et al. (four-wheeled drive tower). However, these attempted solutions have been complex and expensive to implement and appear to have had only limited acceptance in the marketplace.

There is a need in the industry for an improved drive tower for self-propelled irrigation systems to allow the irrigation systems to traverse difficult and uneven terrain more easily.

SUMMARY OF THE INVENTION

An improved drive tower for self-propelled irrigation systems according to the present invention has a base beam assembly, a tower structure extending above the base beam assembly for supporting an elongated pipeline, and a plurality of drive wheel assemblies for moving the base beam assembly over a field. The drive assemblies include first and second drive assemblies mounted to respective ends of the base beam assembly, and a third drive assembly mounted to the base beam assembly between the first and second drive assemblies. The base beam assembly is articulated between its first and second ends and pivotally connected to the lower ends of the tower structure to allow the third drive assembly to move vertically relative to the first and second drive assemblies when traversing uneven terrain.

According to one broad aspect of the present invention, a drive tower for a self-propelled irrigation system is provided, comprising: a base beam assembly comprising a first beam member pivotally connected to a second beam member, the first and second beam members being rotatable relative to each other about a first pivot connection; a tower structure comprising first and second tower members, the first tower member being pivotally connected at its lower end to the first beam member about a second pivot connection, the second tower member being pivotally connected at its lower end to the second beam member about a third pivot connection, and the first and second tower members extending upwardly from the second and third pivot connections and converging together to support an elongated water pipeline above the base beam assembly; and a plurality of drive assemblies mounted to the base beam assembly for supporting and propelling the base beam assembly over a field.

According to another broad aspect of the present invention, a drive tower for a self-propelled irrigation system is provided, comprising: a base beam assembly; a tower structure supported by and extending above the base beam assembly for supporting an elongated water pipeline above the base beam assembly; a plurality of drive assemblies for supporting and propelling the base beam assembly over a field, the drive assemblies comprising first and second drive assemblies mounted to respective first and second ends of the base beam assembly, and a third drive assembly mounted to the base beam assembly between the first and second drive assemblies; and the base beam assembly being articulated at a location between its first and second ends to allow the third drive assembly to move vertically relative to the first and second drive assemblies when traversing uneven terrain.

Numerous other objects of the present invention will be apparent to those skilled in this art from the following description wherein there is shown and described an embodiment of the present invention, simply by way of illustration of one of the modes best suited to carry out the invention. As will be realized, the invention is capable of other different embodiments, and its several details are capable of modification in various obvious aspects without departing from the invention. Accordingly, the drawings and description should be regarded as illustrative in nature and not restrictive.

DETAILED DESCRIPTION OF THE INVENTION

A self-propelled irrigation system10with an articulated drive tower according to the present invention will now be described in detail with reference withFIGS. 1 to 9of the accompanying drawings.

The self-propelled irrigation system10has an elongated pipeline11supported above a field by a plurality of drive towers12. The irrigation system10can be a center pivot system in which the pipeline11is connected to a fixed center pivot13at the center of a field, as illustrated inFIG. 1. Alternatively, the irrigation system10can be a linear move system (not shown) in which the pipeline is carried across a field in a linear manner without a fixed center pivot point. A water supply pipe14from a surface water pump or well is connected to the pipeline11to supply irrigation water through the pipeline11to be distributed over the field. A plurality of sprinkler nozzles or the like are spaced along the pipeline11for applying water to the field in a known manner.

At least one of the drive towers12of the irrigation system10is equipped with an articulated arrangement of drive wheel assemblies according to the present invention. The drive tower12has a base beam assembly15, a tower structure16extending above the base beam assembly15for supporting the elongated pipeline11above the base beam assembly15, and a plurality of drive wheel assemblies17,18,19for supporting and propelling the base beam assembly15over a field.

The base beam assembly15has a first beam member20pivotally connected to a second beam member21at a first pivot connection22. The first beam member20is rotatable relative to the second beam member21about a pivot axis extending in a generally transverse horizontal direction relative to the base beam assembly15. The first pivot connection22provides an articulation between the first and second ends24,25of the base beam assembly15(e.g., near the midpoint of the base beam assembly15).

The tower structure16has first and second tower members26,27extending between the elongated pipeline11and the base beam assembly15. The first tower member26is pivotally connected at its lower end to the first beam member20about a second pivot connection28. The second tower member27is pivotally connected at its lower end to the second beam member21about a third pivot connection29. The second pivot connection28is located between the respective ends of the first beam member20, and the third pivot connection29is located between the respective ends of the second beam member21. The second and third pivot connections28,29are preferably located closer to the respective outer ends24,25of the base beam assembly15than to the midpoint of the base beam assembly15to balance the weight of the system10between the three drive wheel assemblies17-19. The second and third pivot connections28,29allow rotation of the beam members20,21relative to the tower members26,27about respective pivot axes extending in generally transverse horizontal directions relative to the base beam assembly15.

The first and second tower members26,27extend upwardly from the second and third pivot connections28,29and converge together at their upper ends to support the elongated water pipeline11above the base beam assembly15. A suitable bracket30is used to attach the elongated pipeline11to the upper ends of the tower members26,27.

The drive wheel assemblies include first and second drive wheel assemblies17,18mounted to the respective ends24,25of the base beam assembly15, and a third drive wheel assembly19mounted to the base beam assembly15between the first and second drive wheel assemblies17,18. The third drive wheel assembly19is mounted to the base beam assembly15between the second and third pivot connections28,29. The second pivot connection28is located between the first and third drive wheel assemblies17,19, and the third pivot connection29is located between the second and third drive wheel assemblies18,19.

The articulation in the base beam assembly15provided by the first pivot connection22allows the third drive wheel assembly19to move vertically relative to the first and second drive assemblies17,18when the drive tower12traverses uneven terrain. The second and third pivot connections28,29allow the first and second beam members20,21to pivot relative to the lower ends of the respective tower members26,27when the base beam assembly15articulates. The tower structure16also flexes slightly to accommodate the small change in distance between the second and third pivot connections28,29as the base beam assembly15articulates.

The drive wheel assemblies17-19in the illustrated embodiment each include a gear box31and a driven wheel32connected to an output shaft of the gear box31. A common drive motor assembly33can be provided for driving the drive wheel assemblies17-19. For example, the first, second and third drive wheel assemblies17-19can be interconnected together by a plurality of drive shaft assemblies34-36that transfer rotational drive force from a drive motor37to the drive wheel assemblies17-19. The drive shaft assemblies34-36each have a shaft39surrounded by a protective sleeve40and boots41, as shown inFIG. 7.

In the illustrated embodiment, the drive motor37is connected to a main drive gear box38having first and second output shafts. A first drive shaft assembly34connects the first output shaft of the main drive gear box38to the first drive wheel assembly17. A second drive shaft assembly35connects the second output shaft of the main drive gear box38to the third wheel drive assembly19. A third drive shaft assembly36connects the third drive wheel assembly19to the second wheel drive assembly18.

In use, the self-propelled irrigation system10can be moved over a field by activating the drive motor37to drive the first, second and third drive wheel assemblies17-19via the drive shaft assemblies34-36. The weight of the irrigation system10is substantially evenly distributed between the first, second and third drive wheel assemblies17-19as a result of the arrangement of the pivot connections22,28,29. As the system10traverses uneven terrain, the third drive wheel assembly19moves vertically relative to the first and second drive wheel assemblies17,18to follow the terrain while maintaining a constant weight distribution between the wheel assemblies17-19. The articulated drive tower12of the present invention can be used in locations where conventional drive towers are prone to getting stuck in the mud and in applications where shallower wheel tracks are desired.

Various changes can be made to the irrigation system10illustrated in the drawings without departing from the scope of the invention. For example, the irrigation system can have a combination of conventional drive towers together with one or more articulated drive towers of the present invention. For another example, the drive assemblies can be powered by electrical motors, hydraulic drive motors, or other conventional power units. For yet another example, the drive assemblies can be supported by wheels, tracks, or other suitable wheel substitutes known in the industry. Each drive assembly can be supported by a single wheel or a plurality of wheels.

The articulated drive tower of the present invention provides several advantages over the prior art. The articulated drive tower is able to flex to ensure that all three drive wheels remain in contact with the ground. The articulated drive tower provides better floatation resulting in better traction and shallower tracks because substantially equal loads are carried by each tire on uneven terrain. Shallower tracks are desirable to reduce interference with field operations, such as harvesting. The drive tower also provides added stability on steep elevation changes, such as terraces and washouts.

While the invention has been specifically described in connection with specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.