Abstract:
A reaction drive sprinkler includes an improved drive assembly for rotating the sprinkler in steps about a water supply standpipe. The drive assembly comprises a fixed drive nozzle through which an inclined stream of irrigation water is projected for passage through a movable diverter tube mounted in front of the drive nozzle. The diverter tube is shifted by a reversing mechanism for slightly diverting the water stream for alternated interruption by a pair of laterally oppositely angled deflector spoons on a pivoting reaction drive arm. More particularly, the diverter tube directs the water stream for cyclic interruption by one of the deflector spoons to rotate the sprinkler stepwise in one direction through a selected arcuate path and then shifts the diverter tube to direct the water stream for interruption by the other deflector spoon for stepwise sprinkler rotation in the opposite direction.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to rotatable irrigation sprinklers particularly of the type including a reaction drive member for interacting cyclically with a projected water stream to rotate the sprinkler in steps and thereby alter the azimuthal direction of the water stream. More specifically, this invention relates to an improved drive assembly for a reaction drive sprinkler of the general type disclosed and claimed in U.S. Pat. No. 4,434,937. 
     Rotatable water sprinklers of the so-called reaction drive type are known in the art for supplying irrigation water over a substantial surface area to irrigate lawns, crops, and the like. Such reaction drive sprinklers typically comprise a sprinkler body supported by a bearing assembly for rotation about the upper end of a water supply standpipe. Irrigation water under pressure supplied through the standpipe flows upwardly through the sprinkler body and is discharged outwardly through a discharge outlet or nozzle with a selected angle or upward inclination. A reaction drive arm is mounted on the sprinkler body for pivoting movement typically within a generally vertical plane and is appropriately counterweighted to swing a laterally open curved deflector spoon cyclically into interrupting engagement with the projected water stream. The water stream interacts with the deflector spoon to swing the spoon away from the stream and further to impart a lateral torque transmitted through the drive arm to the sprinkler body to rotate the sprinkler through a relatively small step, after which the drive arm returns the deflector spoon for subsequent water stream interruption and sprinkler rotation through a subsequent step. Accordingly, the deflector spoon interrupts the water stream in a cyclic fashion to rotate the sprinkler through a series of relatively small steps thereby correspondingly altering the direction of throw of the projected water stream. This stepwise movement can be allowed to continue through repeated full-circle rotations, or alternatively, if desired, a suitable reversing mechanism can be provided to reverse the direction of rotation within the limits of a preselected arcuate path. 
     Reaction drive water sprinklers of the type described have been used widely in agricultural irrigation systems requiring a relatively high flow water stream to be projected a substantial distance from the sprinkler. In this type of sprinkler, sometimes referred to as a large gun or big gun sprinkler, the deflector spoon interacts with the high energy water stream to drive the sprinkler in steps in one rotational direction. For part-circle operation, a reversing mechanism responds to sprinkler movement reaching one end limit of a selected arcuate path to move a reversing cam into interrupting engagement with the high energy stream. This results in a relatively high reaction force swinging the sprinkler rapidly back through the arcuate path to the other end limit whereupon the reversing cam is retracted from the water stream and normal stepwise rotation by means of the deflector spoon is resumed. Commercial examples of the foregoing type of reaction drive sprinkler are the Model 102 and Model 103 Rain Guns manufactured by Rain Bird Sprinkler Mfg. Corp. of Glendora, Calif. In such reversible reaction drive sprinklers, the provision of a reversing cam and related actuating components undesirably increases the overall cost and complexity of the sprinkler. Moreover, reversing cam engagement with the high energy water stream can cause extremely rapid reversed rotational movement which can in turn contribute to excessive component wear and/or failure of mechanical components. Still further, interruption of the high energy water stream by the deflector spoon and the reversing cam knocks down a portion of the stream thereby effectively reducing sprinkler range. 
     In U.S. Pat. No. 4,434,937, an improved reaction drive sprinkler is disclosed of the so-called large or big gun type. This improved reaction drive sprinkler includes a relatively large range tube through which a high flow, high energy water stream is projected a substantial distance from the sprinkler, together with a comparatively smaller drive nozzle through which a secondary, significantly lower energy water stream is projected for reversible driving purposes. This lower energy water stream is interrupted in a cyclic manner by one of a pair of oppositely curved deflector spoons carried on a pivoting reaction drive arm, with the drive nozzle being formed from a flexible rubber-based or plastic material movable to aim the lower energy stream for engagement with either deflector spoon in accordance with the desired direction of rotational sprinkler stepping movement. The flexible drive nozzle can thus be set to rotate the sprinkler stepwise through a full-circle path in either direction or the drive nozzle can be switched by a reversing mechanism back and forth to achieve reversible sprinkler stepwise rotation within the limits of a preselected arcuate path. While this use of the relatively low energy stream for driving purposes advantageously results in controlled sprinkler movement in both rotational directions together with reduced component wear, the flexible drive nozzle has not provided consistent drive performance particularly when subjected to varying operating parameters, such as temperature or pressure. For example, variations in these and other parameters can produce widely variant physical characteristics for the lower energy drive stream thereby resulting in unacceptably inconsistent reaction drive forces and sometimes making it difficult to aim the stream for proper interaction with the selected deflector spoon. 
     There exists, therefore, a significant need for an improved drive assembly for a reaction drive sprinkler of the general type described in U.S. Pat. No. 4,434,937, wherein the improved drive assembly includes means for providing a relatively low energy water stream having substantially consistent drive characteristics and wherein this water stream can be shifted accurately back and forth for controlled interruption by two oppositely oriented deflector spoons. The present invention fulfills these needs and provides further related advantages. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, a reaction drive sprinkler is provided with an improved drive assembly for forming and directing an outwardly projected stream of irrigation water into interrupting engagement with one of two laterally open, oppositely curved deflector spoons on a pivoting reaction drive arm. The drive assembly comprises a fixed drive nozzle through which the water stream is projected, and diverter means movably positioned between the drive nozzle and the deflector spoons for controlled slight diversion of the water stream into reaction engagement with the selected one of the deflector spoons. The diverter means is shifted by a reversing mechanism between a first position diverting the stream for engagement with one of the spoons to drive the sprinkler in one rotational direction and a second position diverting the stream for engagement with the other spoon to drive the sprinkler in the opposite rotational direction. 
     In one preferred form of the invention, the reaction drive sprinkler includes a sprinkler body adapted for rotatable mounting onto the upper end of a water supply standpipe. The sprinkler body includes a relatively large, outwardly inclined range tube through which a high flow, relatively high energy uninterrupted water flow stream is projected. The drive nozzle is positioned generally along the inside curvature of a range tube elbow portion for bleed discharge of a comparatively lower flow, lower energy water stream for reaction engagement with the deflector spoons. The drive nozzle is fixed in position and formed preferably from an abrasion-resistant long-life material, such as brass or the like, and is supported on the range tube for projecting the low energy stream upwardly and outwardly generally in parallel with the high energy stream discharged from the range tube. The deflector spoons are carried at the forward end of a counter-weighted reaction drive arm mounted on the range tube for pivoting movement through a generally vertical plane. The deflector spoons are defined by oppositely curved, laterally open deflector walls, such that engagement of one of the spoons by the low energy water stream results in a laterally directed force for rotating the sprinkler body in a small rotational step about the axis of the water supply standpipe. 
     The preferred diverter means comprises a diverter tube supported between the drive nozzle and the deflector spoons. This diverter tube has an enlarged flared inlet end for reception of the low energy water stream discharged from the drive nozzle, wherein this inlet end converges to and merges with a generally cylindrical guide tube through which the low energy stream is projected for impact engagement with the selected deflector spoon. A movable support bracket carries the diverter tube and is shifted by the reversing mechanism between the first and second positions orienting the diverter tube for diverting the low energy stream laterally through a small angle into respective engagement with the two deflector spoons. 
     The reversing mechanism includes an actuator arm carried by the range tube and operatively coupled by an over-center spring or the like to the support bracket to shift the support bracket between the first and second positions. Trip means on the actuator arm is responsive to sprinkler rotational movement to one of the end limits of a preselected arcuate path of movement to displace the actuator arm thereby shifting the support bracket and diverter tube between the first and second positions. 
     Other features and advantages of the present invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings illustrate the invention. In such drawings: 
     FIG. 1 is a fragmented side elevation view of a reaction drive sprinkler, shown partially in vertical section, including the improved drive assembly embodying the novel features of the invention; 
     FIG. 2 is a fragmented sectional view taken generally on the line 2--2 of FIG. 1; 
     FIG. 3 is a fragmented sectional view taken generally on the line 3--3 of FIG. 1; 
     FIG. 4 is a fragmented sectional view through a portion of the drive assembly, taken generally on the line 4--4 of FIG. 1, and depicting the drive assembly in a first operating position; 
     FIG. 5 is a fragmented sectional view similar to FIG. 4 but illustrating the drive assembly in a second operating position; 
     FIG. 6 is a fragmented sectional view of another portion of the drive assembly, taken generally on the line 6--6 of FIG. 1, and depicting the drive assembly in the first operating position; 
     FIG. 7 is a fragmented sectional view through a further portion of the drive assembly, taken generally on the line 7--7 of FIG. 1 and depicting the drive assembly in the first operating position; 
     FIG. 8 is a fragmented sectional view similar to FIG. 6 but illustrating the drive assembly in the second operating position; and 
     FIG. 9 is a fragmented sectional view similar to FIG. 7 but illustrating the drive assembly in the second operating position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in the exemplary drawings, a reaction drive sprinkler referred to generally by the reference number 10 includes an improved drive assembly 12 for rotationally stepping the sprinkler in relatively small increments about the axis of a water supply standpipe 14. The drive assembly 12 includes a diverter tube 16 movably positioned by a reversing mechanism 18 for slightly diverting a relatively low energy water stream 20 into driving engagement with a selected one of a pair of oppositely curved deflector spoons 22 and 24 to control the direction of sprinkler stepping movement. 
     The reaction drive sprinkler 10 corresponds generally with the reaction drive sprinkler disclosed and claimed in commonly assigned U.S. Pat. No. 4,434,937, with the inclusion of the improved drive assembly 12. More particularly, as shown best in FIGS. 1 and 2, the reaction drive sprinkler 10 comprises a sprinkler body of an appropriate metal casting or the like defining a relatively large bore range tube 26 having a lower end 28 rotationally supported by a bearing assembly 30 which in turn is adapted for mounting onto the upper end of the water supply standpipe 14. The lower end 28 of the range tube 26 extends upwardly from the bearing assembly 30 and merges smoothly with a curved elbow portion 32 joined in turn with an outwardly inclined discharge barrel 34 having a range tube nozzle 36 at its discharge end. The range tube 26 is thus rotatable within the bearing assembly 30 about a central axis of the standpipe 14, with the bearing assembly 30 having any convenient construction such as that described and claimed in U.S. Pat. No. 4,434,937 to accommodate such rotation. 
     Water under pressure supplied to the reaction drive sprinkler 10 flows upwardly through the water supply standpipe 14 and further upwardly through the range tube 26 for outward projection therefrom as a relatively high energy water stream 38 with a selected angle of inclination. This high energy stream 38 is swept over a substantial terrain surface area, by operation of the drive assembly 12 to be described which rotates the sprinkler through a succession of small rotational steps, to irrigate lawns, crops, and the like. 
     The reaction drive sprinkler 10 is rotatably driven by a relatively low energy water stream discharged from the elbow portion 32 of the range tube 26 and projected as the lower energy stream 20 for cyclic interaction with the deflector spoons 22 and 24. More particularly, a relatively small and inherently relatively low pressure portion of the water flowing through the range tube 26 is passed through a bleed opening 42 disposed along the inside curvature of the range tube elbow portion 32, such that the bleed opening 42 is positioned at a location of substantial water energy losses resulting from localized turbulence and/or vortex swirl within the range tube, as recognized by U.S. Pat. No. 3,924,809. This low energy water passes through the bleed passage and is directed by the improved drive assembly 12 including the diverter tube 16 generally in parallel with the high energy stream 38 toward impact engagement with a selected one of the deflector spoons 22 and 24. 
     The deflector spoons 22 and 24 are supported at the forward end of a reaction drive arm 44 below the discharge barrel 34 of the range tube 26. The illustrative reaction drive arm 44 includes a pair of arm sections 46 extending rearwardly from the deflector spoons on opposite sides of the range tube 26, whereat the arm sections are shaped to define transversely aligned bores 48 for receiving relatively short pivot pins 50 seated in turn by set screws or the like (not shown) within outwardly open sockets 52 on the range tube 26. From the pivot pins 50, the arm sections 46 extend further rearwardly to a position behind the range tube where they are connected in a known manner to an appropriate counterweight (not shown) of selected mass for normally pivoting the deflector spoons upwardly through a generally vertical plane toward the range tube discharge barrel 34, all as shown and described in U.S. Pat. No. 4,434,937 which is incorported by reference herein. 
     The deflector spoons 22 and 24 are defined by a central upstanding divider vane 54 common to both spoons and merging smoothly at its forward end with a laterally oppositely curved pair of upstanding deflector walls 56 and 58. The divider vane 54 and the deflector walls 56, 58 are formed integrally with a lower platform 60 joined to the arm sections 46 by a pair of short side struts 62. Accordingly, the two deflector spoons 22 and 24 are generally upwardly open and further are open in opposite lateral directions to deflect water incident therewith in opposite directions. 
     In operation, the counterweighted reaction drive arm 44 pivots gravitationally to swing the deflector spoons in an upward direction toward interrupting engagement with the projected low energy water stream 20. Conveniently, as is well known in the art, cross vanes 64 pass laterally between the arm sections 46 for initial engagement by the water stream 20 to pull the spoons relatively sharply in an upward direction for full engagement of the selected spoon 22 or 24 with the water stream. As shown best in FIG. 2, when the drive assembly 12 is positioned to guide the stream 20 for engagement with the spoon 22, the low energy water stream is deflected by the associated curved deflector wall 56 laterally away from the spoon 22 resulting in a reaction force imparted to the spoon and transmitted through the reaction arm 44 to the range tube 26 thereby rotating the range tube through a relatively small anglular increment in the direction of arrow 63 with respect to the standpipe 14. Conversely, when the drive assembly diverts the stream 20 for engagement with the other spoon 24, as depicted by dotted lines in FIG. 2, an oppositely directed reaction force results to rotatably drive the range tube 26 through a small step in the opposite direction represented by arrow 65. In either case, the reaction force also drives the deflector spoons downwardly out of engagement with the water stream 20 against the counterweighted mass, whereupon the drive arm 44 eventually overcomes the downward driving force and swings the spoons back upwardly toward interrupting engagement with the water stream and for reaction driving of the rang tube through a subsequent incremental step. 
     The improved drive assembly 12 for controlling the direction of the low energy stream 20 comprises a fixed drive nozzle 66 of a durable abrasion-resistant material, such as brass or the like, retained in seated alignment with the bleed opening 42 and defining a rigid nozzle bore 68 through which the low energy water stream 20 is discharged with highly consistent physical characteristics particularly independent of temperature fluctuations. More specifically, as shown in the exemplary drawings, the drive nozzle 66 comprises an enlarged cylindrical base 70 having a generally frustoconical seat surface for sealing and seated engagement within a matingly shaped counterbore 72 formed in an enlarged seat portion 73 through which the bleed opening 42 extends. This nozzle base 70 is formed integrally with an elongated nozzle tube 74 projecting upwardly and outwardly generally in parallel with the discharge barrel 34 of the range tube 26. The drive nozzle 66 is retained in position by a generally U-shaped retainer spring 76 having its legs receivable through a laterally open slot 78 in the range tube locked within an external annular groove 80 in the nozzle base 70, as shown best in FIGS. 1 and 3. 
     The improved drive assembly 12 further includes the diverter tube 16 formed preferably from a metal such as stainless steel and supported by the reversing mechanism 18 in a position generally between the drive nozzle 66 and the deflector spoons 22 and 24. In the preferred form, this diverter tube 16 has an enlarged or flared inlet end 82 with a diameter somewhat greater than the discharge diameter of the nozzle tube 74 for collecting and receiving the low energy water stream 20 projected from the drive nozzle 66 with an initial direction aimed generally toward the central divider vane 54 common to the two spoons. This flared inlet end 82 of the diverter tube 16 is formed integrally with a generally cylindrical or tubular guide tube 84 from which the low energy stream 20 is guidingly discharged for impact engagement by a selected one of the deflector spoons 22 and 24. More particularly, the reversing mechanism 18 shifts the diverter tube 16 back and forth between the first position represented by solid lines in FIG. 2 for laterally diverting the stream 20 from its normal course through a small angle for impact engagement with the deflector spoon 22 thereby reaction driving the sprinkler in steps in the direction of arrow 63. Alternatively, the reversing mechanism 18 moves the diverter tube 16 to the second position shown in dotted lines in FIG. 2 for slightly laterally diverting the water stream 20 into impact engagement with the deflector spoon 24, thereby reaction driving the sprinkler in the opposite rotational direction as indicated by arrow 65 in FIG. 2. Importantly, in both cases the angle of stream diversion is sufficiently small, say about 10°, to avoid any significant reduction in stream drive energy. 
     Although the reversing mechanism 18 may take any convenient form, one preferred construction is shown in detail in FIGS. 1 and 4-9. More particularly, the diverter tube 16 is secured as by welding onto the upper end of a support bracket 92 which is in turn pivoted by a pivot pin 96 onto a support arm 94 projecting forwardly from the seat portion 73. The lower end of this support bracket 92 includes a forwardly open, generally U-shaped recess 100 (FIG. 6) bounded by forwardly projecting legs 102 for respectively contacting at the first and second diverter tube positions, respectively, a stop pin 104 on the support arm. The support bracket 92 further carries a downwardly open boss 106 at a position near the forward recess 100 to capture one end of an over-center trip spring 108 having its opposite end captured in an upwardly presented boss 110 on an actuator arm 112. 
     The actuator arm 112 is pivoted on the support arm 94 by a forward pivot pin 114, with an upper bracket portion of the actuator arm including a rearward recess 116 bounded by rearwardly projecting legs 118 and 120 for respectively contacting the stop pin 104. The actuator arm 112 extends downwardly from the support arm 94 and rearwardly past the lower boss 110 and terminates in a U-shaped end 122 which supports a downwardly extending trip pin 124. Conveniently, a C-shaped clip spring 126 releasably retains the trip pin 124 in a downwardly extending position. 
     The trip pin 124 is positioned to engage outwardly projecting tabs 128 and 130 at the ends of clamp springs 132 and 134 wrapped about the bearing assembly 30, wherein these tabs 128 and 130 can be selectively positioned about the circumference of the bearing assembly 30 to define the opposite end limits of a preselected arcuate path within which sprinkler rotation is desired. When the sprinkler rotation in one direction, as depicted by arrow 63, reaches the end limit defined by the tab 128, as viewed in FIGS. 4, 6, and 7, the trip pin 124 engages the tab 128 to pivot the actuator arm 114 relative to the support arm 94, thereby operatively pivoting the support bracket 92 via the trip spring 108 to the second position, as shown in FIGS. 5, 8, and 9. This pivoting movement of the support bracket 92 shifts the diverter tube 16 to the second position for guiding the low energy water stream 20 into interaction with the other deflector spoon 24. When this occurs, rotational stepping movement of the sprinkler reverses and continues in the opposite direction, as indicated by arrow 65, until the trip pin 124 engages the other clamp spring tab 130 thereby activating the reversing mechanism 18 to return the diverter tube 16 to its original first position and against the diurection of stepping motion. 
     The improved drive assembly 12 thus provides a relatively simple and substantially maintenance free diverter means for shifting the low energy water stream 20 into engagement with the selected deflector spoon 22 or 24 to controllably drive the sprinkler 10 in the desired rotational direction. This controlled directional driving is advantageously accomplished by reliable and consistent drive forces which are not significantly impacted by ambient temperatures, time of service, or other factors. 
     A variety of modifications and improvements to the improved drive assembly for a reaction drive sprinkler described herein are believed to be apparent to those skilled in the art. Accordingly, no limitation on the invention is intended by way of the description herein, except as set forth in the appended claims.