Abstract:
A remotely operable anchoring system for a mobile irrigation apparatus includes anchoring units mounted to irrigation towers. The anchoring units are remotely operable through a control module and have anchor members which, upon command, can be moved by the anchoring units from a retracted position to an extended position in which each anchor member penetrates and anchors itself into the soil beneath the irrigation tower. Upon command, after the danger of high wind has passed, each anchor member may be retracted from the extended position to the retracted position in preparation for future use.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application 61/833,625 filed on Jun. 11, 2013, which is incorporated herein by reference. 
    
    
     FIELD 
     This invention relates to an apparatus that can be activated to anchor an irrigation tower of a mobile irrigation apparatus to prevent the irrigation tower from overturning in high wind conditions. 
     BACKGROUND 
     Pivot irrigation systems are used by dryland farmers to irrigate circular areas of square portions of farmland which usually extend approximately 2,640 feet on each side. Accordingly, a mobile irrigation system may include a stationary pump, an irrigation pipe elevated by mobile towers which feeds spaced irrigation heads which broadcast water. A common configuration is a center pivot system in which an elevated irrigation pipe and spaced irrigation heads are arranged radially from a center pivot including a stationary pump for supplying water to the center pivot system. Center pivot irrigation systems usually broadcast water in circular, semi-circular and even quarter-circular patterns. Mobile irrigation towers are usually supported by powered wheels for gradual movement. In a center pivot system, the wheel rotation rate is in proportion to the distance between the tower and the center pivot. In a center pivot system, the irrigation heads broadcast water at rates that are also proportional to their distances from the center pivot. Although the applicant will refer to “pivot irrigation systems” in this specification, the skilled reader should understand that this also includes so called “windshield wiper” irrigation systems used for irrigating rectangular areas of farm ground or smaller areas and even mobile tower systems which do not pivot about a center. Non-pivoting systems included an elongated raised pipe supported by evenly spaced mobile irrigation towers which all move at a constant in order to irrigate rectangular strips of land. The mobile towers of such strip irrigation systems are also susceptible to being overturned by high winds. 
     A significant risk encountered by farmers using mobile irrigation systems is the tendency of the elevated irrigation pipe and the mobile towers supporting the pipe to overturn in high wind conditions which occasionally occur in areas of the Midwest. The tendency to overturn is most pronounced in a center pivot system toward the distal end of the elevated irrigation pipe. Further, it is generally advantageous to build pivot irrigation systems from lightweight structures and materials in order to minimize power consumption, material use and soil compaction. This further increases the likelihood of the irrigation structure overturning during a storm. Still further, when the system is idle, it is typically drained of water, thereby reducing the weight of the irrigation structure and its ability to withstand high winds. What is needed is an apparatus that will anchor irrigation towers during high wind conditions, and more particularly, anchor the towers toward the distal end of the irrigation pipe. 
     SUMMARY 
     The above noted need is addressed by an anchor apparatus for selectively securing an irrigation tower to the surface of a field. The anchor apparatus includes at least one anchor unit which is fixed to at least one irrigation tower. The anchor unit includes a motor, an anchor member and an anchor member engaging portion. In this example, the anchor member which is an upright helically twisted flat bar which is threaded through the anchor member engaging portion. The motor is mounted on the anchor unit for sliding movement between a first retracted position and a second extended position. The motor is connected to the upper end of the anchor member in order to rotate the anchor member when the motor is activated. The anchor member is adapted for screwing into farm ground soil. When the motor is activated, the anchor member rotates and advances through the anchor member engaging portion as the anchor member penetrates and screws down into the soil beneath the irrigation tower thereby anchoring the anchor unit and the irrigation tower to the ground. As the anchor member advances, the motor translates relative to the anchor unit from the first retracted position to the second extended position. 
     Preferably, the irrigation apparatus includes a plurality of anchor units and a control module which is preferably remotely controllable to activate the motors of the anchor units. Preferably, the control module is remotely operable to operate in at least two modes: a first anchoring mode wherein the motor of each anchoring unit rotates the anchor member in a first direction to move the anchor member from a retracted position to an extended position in which the anchor member is screwed into the farm ground soil beneath the irrigation tower, and a second retracting mode wherein the motor of each anchoring unit rotates the anchor member in a second opposite direction to move the anchor member from the extended position to the retracted position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a first perspective view of an anchoring unit installed on a tower of a center pivot irrigation system. 
         FIG. 2A  is a first perspective view of an anchoring unit shown with the anchor member in a first retracted position. 
         FIG. 2B  is a first perspective view of an anchoring unit shown with the anchor member in a second extended ground engaging position. 
         FIG. 3  is a magnified view of the anchor member engaging portion of the anchoring unit frame. 
         FIG. 4  is a magnified view of the anchor member engaging portion of the anchoring unit frame shown with portions of the anchoring unit frame removed for clarity. 
         FIG. 5  is a cross-section view of the anchor member engaging portion of the anchoring unit frame taken from plane A-A indicated in  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the figures,  FIG. 1  provides a perspective view of an anchoring unit  10  mounted to an irrigation tower  7  of an irrigation apparatus  5  which is situated on the surface of farm ground soil  3 . As can be seen in  FIG. 1 , irrigation tower  7  includes two electric motor driven wheels  4  suitable for moving tower  7  across farm ground soil  3 . In this example, anchoring unit  10  includes an anchor frame  12  which is fixed to irrigation tower  7  and a control module  30 . As can be seen in  FIGS. 2A and 2B , in this example, each anchor unit  10  includes a helically twisted anchor member  40 . 
     Anchor unit  10  is preferably mounted to two or more irrigation towers such as irrigation tower  7  shown in  FIG. 1 . Most preferably, in the case of a center pivot system, anchor units  10  are more frequently mounted to the towers that are most distant from the center pivot because such towers are more susceptible to overturning in high winds than irrigation towers that are closer to the center pivot. When activated, anchor unit  10  advances anchor member  40  so that it penetrates and screws into soil surface  3  thereby anchoring tower  7  in preparation for high wind conditions. Anchor unit  10  is designed to cause the rotation of anchor member  40  as it screws into soil  3  beneath irrigation tower  7 . By operating in a reverse direction, anchor unit  10  can also retract the anchor member  40  by backing it out of the soil for later use. 
       FIGS. 2 and 3  provide magnified views of anchor unit  10 . As can be seen in  FIG. 2 , in this example, anchor unit  10  includes a frame  12 , a motor  30 , a battery and control module  36 , an anchor member  40  and an anchor member engaging portion  44 . In this example, battery and control module  36  contains a battery  36 A and a control transmitter/receiver  36 B for controlling motor  30 . In this example, battery  36 A and control module  36  is fixed to the upper end of frame  12 . Motor  30  is translatably mounted to frame  12  for generally vertical motion between a first retracted position shown in  FIG. 2A  and a second extended position shown in  FIG. 2B . In this example, motor  30  is also mounted so that it cannot rotate relative to frame  12 . 
     Anchor member  40  is generally upright as is frame  12  and fixed to the drive shaft of motor  30  so that it can be rotated by motor  30 . Anchor member  40 , in this example, is fashioned from a steel bar which has a width greater than its thickness. In this example, the applicant has found that a steel bar having a width of approximately 1.5 inches and a thickness of 0.5 inches. The steel bar is preferably twisted about its longitudinal center line into a helical auger like shape thereby defining auger threads which have a pitch defined by the longitudinal distance covered by one full twist. In this example, the selected pitch is 5 inches. Of course, the width, thickness and pitch of the helical bar could vary significantly and still provide an effective anchor member. Still further, it would be possible to contrive other anchor members which would be effective if rotated and advanced into farm ground soil. It is also preferable that the distal end of anchor member  40  is pointed and that it has sharpened edges. An anchor member  40  which is fashioned in this manner can be screwed into farm ground soil when it is rotated about its center line and advanced or at least allowed to advance by a distance which is approximately equal to the pitch of the anchor member when the anchor member rotates a complete revolution. In this example, anchor member  40  has a length of 75 inches and the depth of penetration into the farm ground soil at full anchoring extension is preferably about 48 inches. 
     In order to drive anchor member  40  as described above, the applicant has found it is advantageous to employ an electric motor  30  that develops between 500 and 900 in-lbs of torque at between 20 and 30 rpm. In this example, the applicant used an electric 12 volt DC 28.6 amp motor rated at 739 ft-lbs at 24 rpm. This translates to approximately 0.45 hp or about 340 watts. Those skilled in the art will readily appreciate that such electric motor  30  could be substituted with a hydraulic motor or even an air motor having similar power output characteristics. 
     Anchor member engaging portion  44  is best understood by referring to  FIGS. 3-5 . In this example, anchor member engaging portion  44  is preferably located at the lower end of frame  12 . Anchor member engaging portion  44  includes a lower plate  48 A and an upper plate  48 B and two diagonally mounted cylindrical rods  46 A and  46 B which are disposed opposite each other. Rods  46 A and  46 B are fixed at their opposite ends to upper and lower plates  48 A and  48 B and further arranged to extend diagonally in opposite direction between plates  48 A and  48 B as shown in  FIGS. 3 ,  4  and  5 . Rods  46 A and  46 B are arranged to engage and fit into the spiral grooves presented by anchor member  40 . Lower and upper plates  48 A and  48 B also present vertically aligned round holes  48 A 1  and  48 B 1  which receive anchor member  40 . Thus, anchor member  40  is constrained to align with holes  48 A 1  and  48 B 1  it engages rods  46 A and  46 B. With this arrangement, as anchor member  40  turns with respect to anchor member engaging portion  44 , anchor member  40  either advances through anchor member engaging portion  44  or retracts through anchor member engaging portion  44  depending on the direction of rotation.  FIG. 5  is a cross section view taken from plane A-A indicated in  FIG. 4 . As can be seen in  FIG. 5 , rod  48 B is received by the round groove presented by the auger like twisted surface of anchor member  40 . The same is the case for the opposite rod  48 A. Rods  48 A and  48 B have the advantage of contacting anchor member  40  along limited curved surfaces of anchor member  40  which the applicant believes minimizes the friction generated by the interaction of anchor member  40  and rods  48 A and  48 B. 
     Those skilled in the art will appreciate that anchor member engaging portion may also take the form of a female threaded portion which is fixed to frame  12  and which presents internal threads corresponding to the external threads presented by anchor member  40 . Such a female threaded member could be a block of material having a negative volume removed which would correspond to the shape of anchor member  40 . Such a block of material, possibly molded from Teflon or a similar low friction polymer could provide a threaded member for receiving anchor member  40 . Thus, when motor  30  rotates and powers anchor member  40  while being free to translate toward the lower end of frame  12  as anchor member  40  advances through anchor member engaging portion  44 , anchor member  40  contacts farm ground soil  3  and subsequently screws into farm ground soil  3  thereby anchoring irrigation tower  7  to prevent irrigation tower  7  from overturning in high wind conditions. Because anchor member engaging portion  44  causes anchor member  40  to advance by its pitch for every full rotation, anchor member engaging portion  44  provides the useful function of advancing anchor member  40  by an appropriate distance each time anchor member  40  rotates. However, those skilled in the art will appreciate that other means might be employed to advance motor  30  and anchor member  40  at a speed which is suitable for the rotation speed and pitch of anchor member  40 . 
     Control module  36  shown in  FIG. 1  is preferably capable of receiving and responding to wireless signals. Preferably, an operator should be able to remotely activate anchoring apparatus  10  which would initiate a sequence which would shut down irrigation system  5  if it is operating and then deploy anchor members  40  as described above. Preferably, a master control module would be present to execute the following steps upon receiving an appropriate signal: (1) Shut down the irrigation system so that no water is pumping and so that tower drive wheels are not turning. (2) Activate all of the anchor units to advance the anchor members from the retracted position to the extended position such that each anchor member penetrates the ground beneath its respective irrigation tower. Preferably also, the master control module would have the capability, upon receiving an appropriate “all clear” signal to do the following (1) withdraw all of the anchor members back to the retracted position, and (2) resume irrigation operations if needed. 
     Control module  36  also includes battery  36 A as noted above. Since irrigation apparatus  5  typically includes an electrical system (not shown), it is possible to connect battery  36 A to the electrical system of irrigation apparatus  5  and maintain battery  36 A fully charged at all times. 
     As can be seen from the above description, the anchoring apparatus described above provides an effective means for selectively anchoring the towers of an irrigation system to prevent the extensive damage that can occur in high wind conditions. Numerous variations in the control system protocol can be envisioned. For example, high wind prediction data could be automatically accessed via on-line resources and evaluated to automatically generate commands to shut down irrigation systems and deploy anchors against predicted high wind conditions. However, such systems are configured, they generally need to be robust and capable of operating under their own power. 
     It is to be understood that while certain forms of this invention have been illustrated and described, it is not limited thereto, except in so far as such limitations are included in the following claims and allowable equivalents thereof.