Abstract:
An adjustable sprinkler including: a sprinkler head having a bearing mounted on a support, the sprinkler head rotatable on the bearing about a vertical axis; an arc adjustment plate mounted on the support for rotation about the axis relative to the support and to the bearing; first and second stops supported on the plate for arcuate movement about the axis, at least one of the stops movable relative to the plate, wherein the first and second stops define limits of rotational movement of the sprinkler head about the axis; and a fluid actuator for moving one of the stops relative to the other of the stops for varying the limits of rotational movement of the sprinkler head.

Description:
[0001]    Priority is claimed from U.S. Provisional Application Ser. No. 60/897,836, filed Jan. 29, 2007. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention generally relates to irrigation sprinklers, and more specifically, to an automatic arc adjustment device for a high-volume sprinkler. 
         [0003]    High-volume sprinklers are often used to irrigate large fields, and they are typically attached to a hose reel stationed at one end of the field. In use, the hose is extended to its full length by means of a traveling cart with a high-volume sprinkler located on the cart. When the water supply valve is opened, water under pressure travels from the hose reel through the hose, into the cart and is dispensed through the sprinkler nozzle. As the water is applied over the area to be irrigated, the hose is slowly rolled back onto the reel, pulling the cart and the sprinkler towards the reel. When the cart and sprinkler reach the hose reel, the irrigation cycle is complete. The reel is then moved to another site where the cycle is repeated. 
         [0004]    Where possible, and for optimum irrigation efficiency, a 270-degree arc is set for the sprinkler. This is set such that, when viewed from overhead, the 90-degree dry spot of the sprinkler is centered upon the hose being pulled towards the hose reel. This arrangement provides the best results in terms of applying water uniformly, and is the most forgiving with respect to countering the effects of wind. 
         [0005]    Oftentimes, however, the farmer starts his cart or traveler with the sprinkler located adjacent a road, fence, or other boundary where a 270-degree arc is not feasible. Accordingly, the farmer manually sets the sprinkler pattern stops initially to provide an arc of 180 degrees, with the boundary of the area to be wetted defined by the fence, road, etc. He starts the sprinkler and operates the hose reel until the cart is pulled into the field far enough that a 270-degree operating arc will be acceptable, and then manually resets the stops on the sprinkler to provide the desired 270-degree arc. This procedure is workable, but requires the farmer or irrigator to be on site to make the required manual stop adjustments. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0006]    The exemplary but nonlimiting implementation of the invention described herein performs the above adjustment procedure automatically through the use of an electro/hydraulic device or mechanism. In the exemplary embodiment, the device is initially adjusted for the 180-degree arc at the field boundary; a timer value is input into a countdown timer attached to a solenoid valve, and the system is started. When the predetermined time value is reached, a solenoid valve is opened, extending a hydraulic cylinder piston operating on system water pressure. The extending piston causes rotation of the adjustment stops of the sprinkler to obtain the desired 270-degree arc. The arc adjustment stops always remain in the correct orientation relative to an associated tripping mechanism that reverses the direction of arcuate movement of the sprinkler head. 
         [0007]    An advantage of the disclosed device is that it can be easily installed in the field. In addition, it is simple in construction, allowing effective trouble-shooting of any mechanical malfunction. 
         [0008]    Accordingly, in one aspect, the invention relates to an adjustable sprinkler comprising: a sprinkler head having a bearing mounted on a support, the sprinkler head rotatable on the bearing about a vertical axis; an arc adjustment plate mounted on the support for rotation about the axis relative to the support and to the bearing; first and second stops supported on the plate for arcuate movement about the axis, at least one of the stops movable relative to the plate, wherein the first and second stops define limits of rotational movement of the sprinkler head about the axis; and an actuator for moving one of the stops relative to the other of the stops for varying the limits of rotational movement of the sprinkler head. 
         [0009]    In another aspect, the invention relates to a sprinkler head having a bearing mounted on a support, the sprinkler head rotatable on the bearing about a vertical axis; an arc adjustment plate mounted on the support for rotation about the axis relative to the support and to the bearing; first and second stops supported on the plate for arcuate movement about the axis, the stops movable relative to the plate and to the support, wherein the first and second stops define limits of rotational movement of the sprinkler head about the axis; and means for automatically moving the arc adjustment plate and the first and second stops relative to the support to vary the limits as a function of time. 
         [0010]    In still another aspect, the invention relates to a method of operating a sprinkler to irrigate a field having at least one end defined by a boundary and a second real or imaginary opposite end comprising: providing a sprinkler cart having a sprinkler head mounted thereon, the cart connected to a hose windable on a hose reel; locating the cart adjacent the boundary at the one end, with the hose reel located at the opposite end; setting the sprinkler head to achieve a 180-degree arc of rotation at the one end, such that water emitted from the sprinkler head does not cross the boundary; winding the hose onto the hose reel to thereby pull the cart away from the boundary at the one end in a direction toward the opposite end; and employing an actuator to automatically set the sprinkler head to achieve a 270-degree arc of rotation, with a remaining 90-degree dry area centered on the hose, when the cart is a sufficient distance away from the boundary at the one end that water emitted from the sprinkler head does not cross the boundary. 
         [0011]    The invention will now be described in connection with the drawings identified below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a schematic plan view of a cart-mounted high-volume sprinkler located at one end of a field to be irrigated; 
           [0013]      FIG. 2  is a schematic view similar to  FIG. 1 , but with the cart drawn further into the field by a hose reel; 
           [0014]      FIG. 3  is a side elevation of the high-volume sprinkler removed from the cart; 
           [0015]      FIG. 4  is a partial enlargement of  FIG. 3 ; 
           [0016]      FIG. 5  is a top perspective view of the high-volume sprinkler shown in  FIG. 3 , with a water deflector in a first operative position; 
           [0017]      FIG. 6  is a partial enlargement of  FIG. 5 ; 
           [0018]      FIG. 7  is a top perspective view similar to  FIG. 5 , but with the water deflector in a second operative position; 
           [0019]      FIG. 8  is a partial enlargement of  FIG. 7 ; 
           [0020]      FIG. 9  is a plan view of the high-volume sprinkler, showing the automatic arc adjustment mechanism; 
           [0021]      FIG. 10  is a plan view similar to  FIG. 9 , but with parts removed to show additional details of the arc adjustment mechanism; 
           [0022]      FIG. 11  is a partial enlargement of  FIG. 10 ; 
           [0023]      FIG. 12  is a side elevation similar to  FIG. 3  but with parts removed; 
           [0024]      FIG. 13  is a view similar to  FIG. 9 , but with the sprinkler rotated clockwise through about 225 degrees; 
           [0025]      FIG. 14  is a view similar to  FIG. 13  but with parts removed; and 
           [0026]      FIG. 15  is a partial enlargement of  FIG. 14 . 
       
    
    
     DETAILED DESCRIPTION 
       [0027]      FIG. 1  shows a schematic aerial or plan view of a field  10  irrigated with a traveler cart (or, simply, “cart”)  12  at the start of the irrigation cycle. The field boundary  14  is the area to be irrigated with all water coming from a high-volume sprinkler  16 , mounted on the cart, to fall within that boundary. The sprinkler  16  may be of the type available from the assignee, Nelson Irrigation Corporation of Walla Walla, Wash., known as the Big Gun® series sprinklers, or any other suitable high-volume sprinkler. 
         [0028]    The end boundary  18  of the field is the boundary to which the cart  12  is initially pulled. A cart hose reel  20  is located at the other end of the field and is connected to the cart  12  by a hose  22  wound on the reel  20 . The “other” end of the field could be a real or imaginary end depending on the length of the field vis-a-vis the length of the hose. An automatic sprinkler arc changer or adjustment mechanism  24  (sometimes referred to herein as “the arc adjustor 24”) is also located on the cart  12 , at the base of the sprinkler  16 . Initially, because of the presence of the end boundary  18 , sprinkler pattern or arc adjustment stops (discussed in detail further below) are set to achieve a 180-degree arc  26 . The sprinkler  16  thus rotates back and forth to irrigate the area described by the arc  26  and end boundary  18 . 
         [0029]      FIG. 2  shows a schematic aerial view of the same irrigated field  10  as in  FIG. 1  but after the cart hose  22  has been wound onto the hose reel  20 , pulling the cart  12  away from the end boundary  18  to a point where a 270-degree operating arc  28  can be safely run without the sprinkler stream extending beyond or outside the end boundary. It is the arc adjustor  24  described in further detail below that implements the arc change from 180 degrees to 270 degrees. 
         [0030]      FIG. 3  is a side view of the high-volume sprinkler  16 . The sprinkler  16  rotates under the power of the water exiting the sprinkler nozzle  30 . Specifically, a drive arm  32  moves up and down as water strikes a drive vane  34  fixed to a remote end of the arm. The drive arm  32  is constructed such that the water, as it leaves the drive vane, causes the drive arm to pivot about a horizontal axis defined by drive arm shaft  36  fixed to the sprinkler body  38 . The sprinkler body  38 , and hence nozzle  30 , also rotate about a vertical axis in the form of a lower bearing unit (or simply lower bearing)  40 , which, in turn, is mounted to the cart  12  via a mounting flange  42 . 
         [0031]      FIG. 4  is a close-up of the lower bearing unit  40 , showing a trip lever  44  and associated arc adjustment components of the sprinkler  16  described further herein.  FIGS. 5-8  illustrate reversal of direction sequence of the sprinkler. For ease of understanding, the description of the structure of the various arc adjustment components is tied to their function in use. As already noted, as the water exits the nozzle  30  at pressure, the drive arm  32  swings upwardly about the shaft  36  and contacts the water stream, a portion of which is deflected (see  FIG. 5 ) by the drive vane  34  causing the sprinkler to rotate in a clockwise direction about the lower bearing  40 . The trip lever  44  is mounted to the sprinkler body  38  and thus rotates with the sprinkler body, but the lever is also free to pivot about the rod or pin  45  (which forms a pivot axis for the lever) on which it is seated. As the sprinkler rotates in the clockwise direction, a trip lever roller  46  mounted to the lower end of the lever  44  will contact a trip face  48  of a clockwise stop  50 . The water will continue driving the sprinkler in a clockwise direction causing the trip lever  44  to rotate about the trip lever pivoting axis  45  in a counterclockwise direction. At an over-center point, an over-center “spring”  52  pivotally attached to a shift lever  56  via pin  53 , as well as to the trip lever  44  via pin  55 , will shift to the other side of a stop bracket  54  (compare  FIGS. 6 and 7 ), rotating the shift lever  56  in a counterclockwise direction about a shift lever pivot axis or bushing  57  that is integrated with a bushing  59  that receives the drive arm shaft  36 . Thus, the counterclockwise rotation of the shift lever also causes counterclockwise rotation of the drive arm (compare  FIGS. 5 and 7 ). Now the water stream impinges on the other side of the vane  34 , causing the sprinkler  16  to rotate in a counterclockwise direction as shown in  FIG. 7  until the trip lever roller  46  contacts a counterclockwise stop  58 , reversing the sprinkler direction through reverse action of the components as described above. The direction-reversal mechanism per se as described above is known in the art. 
         [0032]    With reference now to  FIGS. 9-12  (but with continuing reference to  FIGS. 5-8 ), the pattern or arc adjustment stops  50  and  58  are positioned in  FIGS. 8-11  to provide a 180-degree arc of coverage about an arc “A” ( FIG. 9 ). The arc adjustment mechanism includes a base plate  60  secured to the lower end of the sprinkler, e.g., to the mounting flange  42 . A countdown timer  62  is electrically connected to two latching, three-way solenoids  64  and  66 . The electrical components  62 ,  64  and  66  may be mounted on the base plate  60  or on any convenient support on the sprinkler cart  12 . As shown, solenoid  64  is normally open and effects the 180-degree arc, while solenoid  66 , normally closed, is used to effect the 270-degree arc. The solenoids are connected to a double-acting cylinder  68 , also mounted on the base plate  60 . As explained in greater detail below, in “position one” (for a 180-degree arc) the cylinder piston  70  is retracted, and in “position two” (for a 270 degree arc) the cylinder piston  70  is extended. The cylinder  68  is mounted to the base plate  60  by a cylinder mounting bracket  71 , or any other suitable securement mechanism. 
         [0033]    The piston  70  of the cylinder  68  is attached to a linearly movable rack  72  which drives a drive gear  74  ( FIG. 10 ) about a shaft (or axis)  76  secured to the base plate  60 . The drive gear  74  is attached to a larger diameter multiplier gear  78 , also secured to the base plate. This gear assembly, when driven, rotates an arc adjustment plate/gear housing  80  (also referred to herein as the “arc adjustment plate”, or, simply, “the plate”) via engagement with a gear component  82  of the housing  80 , best seen in  FIG. 12 , and as described in further detail below. 
         [0034]    As best seen in  FIGS. 9 and 10 , the clockwise stop  50  is fixed in the clockwise stop adjustment groove  84  formed in the plate  80 . This groove, extending only about 45 degrees, allows for fine field adjustment of the clockwise sprinkler rotation for the initial 180-degree operation. The counterclockwise stop  58  floats in the counterclockwise stop adjustment groove  86 , also formed in the plate  80 , and is free to move around the centerline axis of the arc adjustment plate, as permitted by the groove  86 , and as limited by external stop posts described below. Thus, the stop  58  is constrained by a first stop post  88  for 180-degree movement (post  88  is adjustably attached to the base plate  60  via groove  89 ), and a 180-degree stop spring  90  which is attached to the arc adjustment plate  80 . In this regard, a stop pin  92  projects from the stop  58  such that it will engage the stop post  88  during counterclockwise rotation of the plate  80  (i.e., when the arc is reset to 180 degrees from 270 degrees), and is then held against the post by the counterclockwise compression spring  90 . 
         [0035]    After a time value entered in the timer  62  has expired, the solenoid  66  will open, causing the piston  70  to move from retracted position one to extended position two as shown in  FIG. 13 . During extension of the piston  70 , the rack  72  rotates the drive gear  74  and multiplier gear  78  which, in turn, rotates the plate  80  via gear component  82  (seen more clearly in  FIG. 12 , and which could be in the form of a simple chain wrapped about the lower housing portion of the plate  80 ) through 225 degrees, thus placing the stops  50  and  58  in their final positions for 270 degrees of sprinkler rotation. More specifically, and with additional reference to  FIGS. 14 and 15 , as the arc adjustment plate  80  rotates from its  FIG. 9  position, i.e., position one, the counterclockwise stop  58  also rotates through approximately 135 degrees until the stop pin  92  contacts a second stop post  96 . Post  96  is also adjustable within a groove  97  and is attached to the base plate  60 . The post  96  “holds” the clockwise stop  58  in this rotational location while the plate  80  continues to rotate. The counterclockwise stop  58  thus “floats” in the counterclockwise stop adjustment groove  86  as the arc adjustment plate  80  continues its rotation through the full 225 degrees. The clockwise rotation of the plate  80  ends with full extension of the piston  70 , prior to when the stop  58  would otherwise be engaged by the end of the groove  86 . Note that the groove  86  may itself extend about 160 degrees, with two adjustable rubber (or similar) stops attached to plate  80  and located within the grove  86 , thus defining the rotation limits of the stop  58  relative to the plate  80 . These rubber or similar stops simply serve to protect the plate by preventing engagement of the stop with the ends of the groove  86 . 
         [0036]    Note that the stop pin  92  will be pressed against the post  96  by the clockwise compression spring  94  as the plate  80  and spring  90  continue rotation relative to the now stationary stop  58  and pin  92 . At the same time, stop  50  has also been rotated to the position shown in  FIG. 14 , so that the sprinkler is now rotatable through a 270-degree arc “B” ( FIG. 15 ), generally between the arrowheads  98 ,  100  on the stops  50 ,  58 , respectively. While the springs  90  and  94  are arranged to compress upon engagement of pin  92  with posts  88  or  96  (and thus push the pin  92  against the posts  88  and  96 ), depending on the direction of rotation of the plate  80 , it will be appreciated that similar springs could be relocated to extend in tension so as to pull the pin  92  into engagement with posts  88  and  96  without departing from the scope of this invention. 
         [0037]    As noted above, rotation of the arc adjustment plate  80  is initiated by the timer  62  and associated solenoids  64 ,  66  that control movement of the piston  70  between retracted and extended positions. The timer  62  is set to cause the piston to extend when the set time period has expired. The time value input to the timer  62  is based on field conditions and cart movement such that sufficient time is allotted to allow the sprinkler cart to move a distance away from the end boundary  18  which will permit a 270-degree arc of coverage that does not project beyond the end boundary  18  behind the sprinkler (see  FIGS. 1 and 2 ). 
         [0038]    In a subsequent cycle, retraction of the piston  70  will rotate the plate  80 , along with stops  50  and  58  to the first position shown in  FIGS. 9-11  for a 180-degree pattern. 
         [0039]    Note that a projection  102  on the sprinkler head will engage upstanding tabs  104 ,  106 , on the stops  50 ,  58 , respectively, insuring that the sprinkler head rotation is confined to arcuate movement between the stops  50  and  58 . It should also be noted that adjustment of the stops  50  and  58  does no harm to the direction reversal mechanism. The sprinkler head necessarily rotates during the change from a 180-degree arc to a 270-degree arc, such that the trip lever will be engaged by the stop  50  and will cause the over-center spring  52  to shift as described above in connection with  FIGS. 6 and 7 . Absent water under pressure flowing through the sprinkler head, this shift is of no consequence. 
         [0040]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.