High volume sprinkler automated arc changerSprinkler Abstract Sprinkler Claims 1. An actuator assembly for a rotatable sprinkler head having a base supported for rotation on a stationary platform assembly, the actuator assembly comprising a hub mounted for rotation on a shaft supported in said base; a lever arm pivotally mounted at one end to said hub and extending downwardly toward a stop plate assembly on said platform assembly, said lever arm having a free end extending toward said stop plate assembly; said stop plate assembly configured to define two or more arcuate paths of travel for said lever arm, said paths being radially offset relative to said hub; and wherein said lever arm is adjustable to locate said free end in any of said two or more arcuate paths of travel. 2. The actuator assembly for claim 1 wherein said stop plate assembly includes an outer ring and an inner stop plate, each concentrically arranged relative to an axis of rotation of said base. 3. The actuator assembly of claim 2 wherein edges of said outer ring define limits of a first arcuate path traveled by said lever arm; and a first set of edges on said inner stop plate define limits of a second arcuate path traveled by said lever arm, wherein said second arcuate path lies radially inwardly of said first arcuate path. 4. The actuator assembly of claim 3 wherein a second set of edges on said stop plate define limits of a third arcuate path traveled by said lever arm, wherein said third arcuate path lies radially inwardly of said second arcuate path. 5. The actuator assembly of claim 1 wherein said lever arm has a first link fixed at one end to said lever arm and pivotally mounted at an opposite end to said hub, and a pair of links, respectively, on either side of said first link, said pair of links each pivotally secured to said lever arm at first ends thereof, and pivotally secured to rods slidably received on said hub at second, opposite ends thereof. 6. The actuator assembly of claim 5 wherein said rods are connected to pistons movable within respective chambers in said hub. 7. The actuator assembly of claim 4 wherein said lever arm has a first link fixed at one end to said lever arm and pivotally mounted at an opposite end to said hub, and a pair of links, respectively, on either side of said first link, said pair of links each pivotally secured to said lever arm at first ends thereof, and pivotally secured to rods slidably received on said hub at second, opposite ends thereof. 8. The actuator assembly of claim 7 wherein said rods are connected to pistons movable within respective chambers in said hub. 9. The actuator assembly of claim 8 wherein pressurization of one of said chambers with a working fluid causes said free end of said lever arm to move outwardly to said first arcuate path. 10. The actuator assembly of claim 9 wherein pressurization of the other of said chambers with the working fluid causes said free end of said lever arm to move inwardly to said third arcuate path. 11. The actuator assembly of claim 10 wherein springs in said chambers cause said free end of said lever arm to move to said second arcuate path when neither chamber is pressurized. 12. The actuator assembly of claim 9 wherein said working fluid is water. 13. An actuator assembly for a large volume sprinkler head mounted for rotation relative to a stop plate assembly, the actuator assembly comprising a lever arm on said sprinkler head adapted to cooperate with said stop plate assembly to define different paths of travel for said sprinkler head; said lever arm movable radially between said different paths of travel. 14. The actuator assembly of claim 13 wherein said stop plate assembly includes an outer ring and an inner stop plate, each concentrically arranged relative to an axis of rotation of said base. 15. The actuator assembly of claim 14 wherein edges of said outer ring define limits of a first arcuate path traveled by said lever arm; and a first set of edges on said inner stop plate define limits of a second arcuate path traveled by said lever arm, wherein said second arcuate path lies radially inwardly of said first arcuate path. 16. The actuator assembly of claim 15 wherein a second set of edges on said stop plate define limits of a third arcuate path traveled by said lever arm, wherein said third arcuate path lies radially inwardly of said second arcuate path. 17. The actuator assembly of claim 16 wherein said lever arm has a first link fixed at one end to said lever arm and pivotally mounted at an opposite end to said hub, and a pair of links, respectively, on either side of said first link, said pair of links each pivotally secured to said lever arm at first ends thereof, and pivotally secured to rods slidably received on said hub at second, opposite ends thereof. 18. The actuator assembly of claim 17 wherein said rods are connected to pistons movable within respective chambers in said hub. 19. The actuator assembly of claim 18 wherein pressurization of one of said chambers with a working fluid causes said free end of said lever arm to move outwardly to said first arcuate path. 20. The actuator assembly of claim 10 wherein pressurization of the other of said chambers with the working fluid causes said free end of said lever arm to move inwardly to said third arcuate path. 21. The actuator assembly of claim 20 wherein springs in said chambers cause said free end of said lever arm to move to said second arcuate path when neither chamber is pressurized. 22. The actuator assembly of claim 19 wherein said working fluid is water. Description [0011] The invention will now be described in greater detail in connection with the various drawing figures identified below. BRIEF DESCRIPTION OF THE DRAWINGS [0012] FIG. 1 is a side elevation of a large volume part circle sprinkler head and arc changer mechanism in accordance with an exemplary embodiment of the invention; [0013] FIG. 2 is a plan view of the sprinkler head shown in FIG. 1, with the barrel of the sprinkler head rotated to a horizontal plane; [0014] FIG. 3 is a plan view of the arc changer mechanism, with the sprinkler barrel removed; [0015] FIG. 4 is a side elevation, partly in section, showing the lever arm in a first outer operative position; [0016] FIG. 5 is a side elevation, partly in section, showing the lever arm in a second intermediate operating position; [0017] FIG. 6 is a side elevation, partly in section, showing the lever arm in a third inner operating position; [0018] FIG. 7 is a plan view of a stop ring and stop plates taken from FIGS. 1-3; [0019] FIG. 8 is a detail taken from FIG. 7; [0020] FIG. 9 is a plan view of a modified stop arrangement; [0021] FIG. 10 is a diagram of a field showing different arcs of travel based on the stops arranged as shown in FIG. 7 in the context of a traveler-type sprinkler; and [0022] FIG. 11 is a diagram of a field showing different arcs of travel based on the stops arranged as shown in FIG. 9. DETAILED DESCRIPTION OF THE INVENTION [0023] With reference to FIG. 1, there is shown a sprinkler head 10 that includes a stationary annular platform assembly 12 adapted to be fixedly mounted at its lower portion on a source pipe or the like (shown in dotted line configuration at 15) for supplying water to the sprinkler head under pressure. Mounted on the platform assembly for rotational movement about a fixed vertical axis A, coincident with the vertical axis of the platform assembly, is a rotating sprinkler body assembly generally indicated at 14. The platform assembly 12 incorporates a brake and bearing arrangement (not shown) that serves to mount the sprinkler body assembly on the annular platform assembly 12 for controlled rotational movement in clockwise or counterclockwise directions. That portion of the platform assembly that receives the sprinkler body assembly 14, as well as the sprinkler body assembly itself, is preferably constructed in accordance with commonly owned U.S. Pat. No. 4,720,045, incorporated herein by reference. [0024] The sprinkler body assembly 14 includes an elbow or base 16 having an elongated barrel 18 fixed thereto. At the outlet end of the barrel 18, there is secured a nozzle 20 serving to direct a stream of water in an upwardly and outwardly direction. Mounted on the barrel 18 for pivotal movement about an axis substantially perpendicular to the longitudinal axis B of the barrel 18 is a yoke 22 that moves between first and second operating positions. The yoke 22 serves to mount an impulse arm assembly 24 for movement with the yoke into two corresponding operating positions and for oscillating movements about a transversely extending oscillatory axis D. Note that axis D is disposed above the longitudinal axis B of the barrel 18 and in a position outwardly of the pivot axis C of the yoke and impulse arm assembly in the downstream direction. [0025] The impulse arm assembly 24 has mounted on its outward end a drive spoon generally indicated at 26. The drive spoon is operable in either of the two operating positions of the yoke or impulse arm assembly and functions to effect continuous oscillatory cycles of the impulse arm assembly 24, during each one of which, the drive spoon 26 is moved into a position of engagement with the stream issuing from the nozzle. The detailed construction and operation of the sprinkler head per se, including the yoke, impulse arm assembly and spoon assembly are well known as described in the above-identified commonly owned patents. The sprinkler head may also be one that is currently available from the assignee, Nelson Irrigation Corp., under the name "SR 150 Big Gun." In addition, the manner in which the sprinkler head rotates in step-wise fashion and reverses direction is also well known as described in the above-identified patents, and need not be described in detail here. This invention relates specifically to an arc changer mechanism for use with the sprinkler head. [0026] The actuator assembly includes a hub 34 mounted for rotation in the elbow 16 via a shaft 30. The actuator assembly also includes a bifurcated lever arm 29 that cooperates with a tube 31 that form part of an overcenter resilient toggle mechanism that facilitates the oscillating motion of the sprinkler. This action is fully described in the '045 patent. [0027] With reference particularly to FIGS. 1, 2 and 4, the lever arm 32 in the exemplary embodiment is pivotally mounted at one end to the housing 36 and hub 34 by means of a fixed link 38 and pivot pin 40. The lever arm 32 is provided at its opposite end with a cam roller 42. Movement about the pivot pin 40 is controlled by a pair of links 44, 46 that are pivotally mounted to the lever arm, on either side of link 38, by respective pivot pins 48 and 50. The upper link 44 is, in turn, pivotally connected to a rod 52 fixed for sliding movement inside the housing 36. Rod 52 is attached to one end of a piston rod 54, an associated piston head 56 slidable within cylinder or chamber 58. Chamber 58 is supplied with working fluid (water, in the exemplary embodiment) via passage 60 in the hub 34. [0028] The lower link 46 is similarly pivotally connected to a second rod 62 via pivot pin 64. Rod 62 is also confined to sliding movement in the housing 36 and is attached to a second piston rod 66. Piston head 68 is slidable within a second cylinder chamber 70 that is supplied with working fluid via passage 72. [0029] The cam roller 42 at the remote end of the lever arm 32 is shown in its upper or radially outermost position in FIG. 4, as a result of water under pressure being supplied to the second chamber 70. This causes piston 66 and rod 62 to push lower link 46 to the left, at the same time pushing the lever arm 32 in a clockwise direction about the pivot pin 40. Note that the absence of water pressure in the first chamber 58 permits the rod 52 and link 44 to move to the right to accommodate the clockwise movement of the lever arm 32. [0030] FIG. 5 illustrates the lever arm 32 in an intermediate position, as a result of balanced return springs 74, 76, acting on the respective pistons with no water pressure in either of chambers 58 or 70. [0031] FIG. 6 illustrates the lever arm 32 in a radially inner and lower position, caused by the supply of water under pressure to the first chamber 58. This pushes piston 54, rod 52 and link 44 to the left, resulting in counterclockwise rotation of the lever arm 32 about the pivot pin 40. The lack of any water pressure in the second chamber 70 permits the link 46 to push the rod 62 and piston 66 to the right. as viewed in the Figure. [0032] With reference now to FIGS. 3 and 7, the platform assembly also includes an outer stop ring 78 that is supported by three circumferentially spaced, generally U-shaped struts 80, 82 and 84 that extend substantially radially between the outer stop ring 78 and a stop plate 86 concentrically located relative to a pipe inlet flange of elbow 16. Stop plate 86 is located below, but parallel to the outer stop ring 78. Edges 88 and 90 of the outer stop ring 78 define the limits of a first path of approximately 180.degree. for the lever arm 32, the lever path indicated by LP1 in FIG. 7. This path will be followed by the lever arm when it is in its extended position, shown in FIG. 4. This path provides the sprinkling pattern designated SP1 in FIG. 10. [0033] A second path LP2 extends between intermediate edges 92, 94 of the stop plate 86 and corresponds to the sprinkling pattern SP2 in FIG. 10. [0034] A third path LP3 extends between inner edges 96, 98 of the stop plate 86 and corresponds to the sprinkling pattern SP3 in FIG. 10. [0035] During a normal sequence of reversing action with the lever arm 32 in the extended position (FIG. 4) in path LP1, the cam roller will not engage the camming surface 92 on the stop plate 86, but will remain radially spaced therefrom as indicated in phantom in FIG. 7, to produce the pattern SP1 in FIG. 10 Note in FIG. 10 that the sprinkler cart is shown at 87, the hose at 89 and the hose reel at 91. [0036] When the arc changing mechanism actuator is actuated to move the lever arm 32 to its intermediate position shown in FIG. 5, so as to begin following path LP2, the cam roller 32 may be within the arcuate range of LP2 or outside the range of LP2. Note that the part of LP1 that is outside the range of LP2 corresponds to the arcuate extent of camming surface 100 on the plate 86. If the lever arm 32 is within the arcuate extent of camming surface 100 when the arc changer is actuated to move it from LP1 to LP2, the roller will be drawn into engagement with surface 100 (see FIG. 8) as the lever arm 32 pivots inwardly about pivot 40. When the roller reaches edge 94, it will fall into the second path LP2 (but it will not engage the inner camming surface 102). If, on the other hand, the lever arm 32 is within the range of LP2, i.e., beyond camming surface 100, it will simply fall into LP2. Note this description assumes clockwise movement of the lever arm 32. The same action will occur in the opposite direction as well. [0037] As the lever arm oscillates between stops or edges 92, 94 in LP2, creating the pattern SP2 in FIG. 10, the roller 42 will not engage camming surface 102 nor the opposite camming surface 104 at the other end of the arc of travel in LP2. [0038] When the arc changer is actuated to move the lever arm 32 into LP3, the lever arm may again be inside or outside the range of LP3. If outside the range, the roller 42 will be caused to engage camming surface 102 (or 104) until it reaches edge 98 (or 96) where it will fall into the path LP3 in the same manner as described above in connection with the transition from LP1 to LP2. In LP3, the lever arm will oscillate between stop edges 96, 98 to create the pattern SP3 in FIG. 10. [0039] While the outer ring 78 and stop plate 86 have been described as fixed in a rigid configuration, other arrangements are contemplated. The outer ring 78 and stop plate 86 may be made rotationally adjustable, and one or more stops may be added. In FIG. 9, for example, two additional stops 106, 108 have been added. Stop 106 will reduce LP1 to a 90.degree. arc of travel, corresponding to SP4 in FIG. 11. Stop 108 will reduce LP2 to a 135.degree. arc of travel corresponding to SP5 in FIG. 11, and stop 108 will also reduce LP3 to a 90.degree. arc of travel corresponding to SP6 in FIG. 11. This arrangement is particularly useful when irrigating next to a fence, building or the like located along the side of the field or lot. [0040] A similar stop plate assembly with different stop sets can be used when the sprinkler is employed as an end gun in a pivot system. The end gun can be turned on and off, with different arcs of travel, as the pivot boom moves into, through and out of the corner area, causing more of the field to be irrigated. [0041] It will also be appreciated that the stop plate 86 may be constructed in two or more sections (indicated by the dotted lines 110, 112 in FIG. 7), with one plate section sliding above or below the other to provide greater flexibility in setting up different arcuate paths for the sprinkler head. [0042] 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.
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