US3669353A

US3669353A - Pivot move agricultural irrigation system with improved water distribution and sprinkler head utilized therewith

Info

Publication number: US3669353A
Application number: US56809A
Authority: US
Inventors: Richard E Hanson; Raymond F Lippitt
Original assignee: L R NELSON Manufacturing CO Inc
Current assignee: L R NELSON Manufacturing CO Inc
Priority date: 1970-07-21
Filing date: 1970-07-21
Publication date: 1972-06-13
Anticipated expiration: 1989-06-13

Abstract

A pivot move agricultural irrigation sprinkler system in which at least a plurality of longitudinally spaced sprinkler heads adjacent the outer end portion of the conduit assembly are arranged to distribute the source of water within the adjacent portion of the conduit assembly onto the forward portion of the adjacent sprinkler head pattern area at an average application rate which is greater than the average application rate at which the water is applied to the rear portion of the adjacent sprinkler head pattern area, the water applied to the forward portion of the sprinkler head pattern area being distributed with a distribution pattern which rises rapidly to a maximum adjacent the leading portion of the sprinkler head pattern area and a sprinkler head for use in such a pivot move system embodying a stream diffusing member mounted for movement into and out of the path of water flowing from the outlet during each cycle of operation and a mechanism for effecting repeated cycles of operation which include step-by-step incremental rotational movement in an operative direction and rotational movement in a reverse direction, one cycle including an operative movement of an arcuate extent greater than 360* but less than 720* and a reverse movement of an arcuate extent equal to the operative movement less 360*.

Description

United States Patent Hanson et al.

[4 1 June 13, 1972 [72] lnventors: Richard E. Hanson, Peoria, lll.; Raymond F. Lippitt, Bethesda, Md.

[73] Assignee: L. R. Nelson Mfg. Co., Inc., Peoria, Ill. [22] Filed: July 21, 1970 [21] Appl. No.: 56,809

[52] US. Cl. ..239/177, 239/212, 239/233,

Primary ExaminerLloyd L. King Assistant Examiner-Reinhold W. Thieme Attorney-Cushman, Darby & Cushman ABSTRACT A pivot move agricultural irrigation sprinkler system in which at least a plurality of longitudinally spaced sprinkler heads adjacent the outer end portion of the conduit assembly are arranged to distribute the source of water within the adjacent portion of the conduit assembly onto the forward portion of the adjacent sprinkler head pattern area at an average application rate which is greater than the average application rate at which the water is applied to the rear portion of the adjacent sprinkler head pattern area, the water applied to the forward portion of the sprinkler head pattern area being distributed 239/010' 1 with a distribution pattern which rises rapidly to a maximum [51] Int. Cl ..B05b 3/12 adjacent the leading portion of the Sprinkler head pattern area [58] Field of Search ..239/177, 212, 230, 233, 255, and a sprinkler head for use in Such a pivot move system 239/DIG' l bodying a stream diffusing member mounted for movement into and out of the path of water flowing from the outlet dur- [56] References cued ing each cycle of operation and a mechanism for effecting re- UNlTED STATES PATENTS peated cycles of operation which include step-by-step incremental rotauonal movement in an operative direction and 3,143,298 8/1964 Jones X rotational movement in a reverse direction one cycle jnclud- Buckner an operative movement of an arcuate extent greater than 2,816,798 12/1957 Royer '239/233 X 360 but less than 720 and a reverse movement of an arcuate 3,559,887 2/1971 y --239/233 extent equal to the operative movement less 360. 3,493,176 2/1970 Kinkead ..239/177 X 3 Claims, 12 Drawing Figures 0 l6 I6 20 l l l v v v V v v 7 v nmm vwv l p H I PATENTEDJUN 13 I972 I SHEET 10F 5 INVENTORS' 5/; YM O/vaFZ/PP r r VMZ JW /JM ATTORNEYS PATENT'EDJIMB m2 3, 569,353

' SHEET 2 OF 5 'INVENTORS Emma/20 Z7192; o/v

flaw Maw FZ/fiP/TT ATTORNEYS PATENTEDJUH 13 m2 3, 669 353 sum 30F 5 ATTORNEYS PATENTEDJUH 1 3 I972 3, 669, 353

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INVENTOR S H/CHARaEEI/vw/v EQYMO/wFL/PP/Ir ATTORNEYS PIVOT MOVE AGRICULTURAL IRRIGATION SYSTEM WITH IMPROVED WATER DISTRIBUTION AND SPRINKLER HEAD UTILIZED TI'IEREWITI-I This application constitutes an improvement of commonly assigned application Ser. No. 56,813, filed concurrently herewith, in the name of Donald R. Sisson and Richard E. Hanson.

This invention relates to agricultural sprinkler irrigation and more particularly to pivot move agricultural sprinkler systems embodying improved step-by-step rotary sprinkler heads capable of accomplishing a more effective water distribution.

In the above-identified application there is disclosed a pivot move agricultural irrigation sprinkler system in which at least a plurality of issuing spaced sprinkler heads adjacent the outer end portion of the conduit assembly are arranged to distribute the source of water within the adjacent portion of the conduit assembly onto the forward portion of the adjacent sprinkler head pattern area at an average application rate which is greater than the average application rate at which the water is applied to the rear portion of the adjacent sprinkler head pattern area by a ratio of the order of between 1.3 to l and 4.0 to l, the water applied to the forward portion of the sprinkler head pattern area being distributed with a distribution pattern which rises rapidly to a maximum adjacent the leading portion of the sprinkler head pattern area and a sprinkler head for use in such a pivot move system having a pair of generally oppositely directed upwardly and outwardly extending outlets, an impulse arm mechanism operated by the stream insuring from one of the outlets, which is smaller than the other larger and generally unobstructed outlet, for effecting a step-by-step incremental rotational movement in one direction through an arcuate extent of approximately 180 and a reversing mechanism for effecting a reverse movement of approximately l80 so that the streams from the two outlets will be distributed with a different distribution pattern and at different average application rates within two generally separate semicircular pattern areas.

An object of the present invention is the provision of a pivot move agricultural irrigation system of this type embodying at least a plurality of sprinkler heads adjacent the outer end portion of the conduit assembly which are operable to achieve the distribution characteristics previously noted and in addition an improved longitudinal uniformity by virtue of the overlapping of individual sprinkler pattern areas within the overall sprinkler head pattern area.

Another object of the present invention is the provision of an improved sprinkler head construction having the operational characteristics of accomplishing the above-mentioned water distribution when used in a pivot move agricultural irrigation sprinkler system.

Another object of the present invention is the provision of a sprinkler head of the type described having improved means for varying the distribution pattern within the sprinkler head pattern area during each separate cycle thereof, one distribution pattern being maximum adjacent the periphery of the pattern area and decreasing toward the axis of the sprinkler head and the other distribution pattern having a maximum adjacent the axis of the sprinkler head and decreasing toward the periphery of the pattern area.

Another object of the present invention is the provision of a sprinkler head of the type described having means for effecting repeated operating cycles each of which consists of an operative step-by-step incremental movement of an arcuate extent greater than 360 but less than 720 and a reverse movement of an arcuate extent equal to the arcuate extent of the operative movement less 360.

Still another object of the present invention is the provision of a sprinkler head of the type described which is simple in construction, effective in operation, and economical to manufacture and maintain.

These and other objects of the present invention will become more apparent during the course of the following detailed description and appended claims.

The invention may best be understood with reference to the accompanying drawings wherein illustrative embodiments are shown.

In the drawings:

FIG. 1 is a top plan view of a pivot move agricultural irrigation system embodying the principles of the present invention;

FIG. 2 is a fragmentary side elevational view of the pivot move system shown in FIG. 1;

FIG. 3 is a fragmentary perspective view of the pivot move system shown in FIG. 1;

FIG. 4 is a perspective view of one form of a sprinkler head embodying the principles of the present invention;

FIG. 5 is a fragmentary top plan view of the outlet nozzle of the sprinkler head shown in FIG. 4, illustrating the impulse arm and reversing arm mechanisms in their normally biased positions;

FIG. 6 is a side elevational view of the structure shown in FIG. 5, illustrating the reversing arm mechanism in three separate positions, in solid lines, dotted lines and phantom lines;

FIG. 7 is an enlarged fragmentary sectional view taken along the line 7-7 of FIG. 4 with the path of movement of the cam roller shown in phantom lines therein;

FIG. 8 is a top plan view of the pattern area of the sprinkler head shown in FIG. 4 with the water distribution within the pattern area indicated by shade lines;

FIG. 9 is a side elevational view, with parts broken away, of another form of sprinkler head embodying the principles of the present invention;

FIG. 10 is a fragmentary sectional view taken along the line 10-10 of FIG. 9;

FIG. 11 is a cross-sectional view taken along the line lll 1 of FIG. 9; and

FIG. 12 is a top plan view of the pattern area of the sprinkler head shown in FIG. 9 with the water distribution within the pattern area indicated by shade lines.

Referring now more particularly to FIGS. 1-3 of the drawings, there is shown therein a pivot move agricultural irrigation system, generally indicated at 10, which embodies the principles of the present invention. As shown, the pivot move system 10 includes a pipe or conduit assembly 12. One end of the conduit assembly'is swivelly connected for pivotal movement about an upright axis with a vertically extending supply pipe or conduit 14. The portion of the conduit assembly 12 extending outwardly from the supply pipe 14 is'supported above 1 the ground by a plurality of ground engaging assemblies 16 operatively connected with the conduit assembly at longitudinally spaced positions therealong.

The construction and operation of the

assemblies

12 and 16 as well as the construction of the source pipe and the manner in which the source pipe is fed a supply of water under pressure is fully disclosed in Zybach U.S. Pat. No. 2,604,359. See also Gordan U.S. Pat. No. 2,893,643, Zybach U.S. Pat. No. 2,941,727 and Harris U.S. Pat. No. 3,484,046 for improvement therein. For purposes of the present invention, it is sufficient merely to note that the conduit assembly 12 is connected in communicating relation with the source of water under pressure flowing from the source pipe 14 and that a portion of the water under pressure flowing in the conduit assembly is utilized as a power source'of propelling each of the ground engaging assemblies 16 so that the entire conduit assembly is moved in a plane parallel with the field about the vertical axis of the source pipe at a predetermined rate of speeds. A detailed understanding of the manner in which this function is accomplished can be obtained by reference to one or more of .the aforesaid patents. It will be understood that the rate of movement of the ground engaging assemblies increases as their position along the conduit assembly from the source pipe increases. It will also be understood that the means for converting the water under pressure into propulsion movement includes a compensating mechanism for varying the speed of propulsion to accommodate variations in the terrain of the field to insure that the conduit assembly will be maintained in substantial longitudinal alignment. The construction of the mechanism for accomplishing this compensating propulsion movement is likewise fully disclosed in the above-mentioned patents, all of which are incorporated by reference herein and to which reference may be had if necessary. The pivot move system also includes a series of step-by-step rotary sprinkler heads, generally indicated at 20, mounted in longitudinally spaced relation along the conduit assembly 12 as by riser pipes 18. The sprinkler heads 20 communicate with the water under pressure within the conduit assembly and serve to distribute the water onto the field during the operative pivotal movement of the system.

The series of sprinkler heads 20 includes at least a plurality of improved sprinkler heads constructed in accordance with the principles of the present invention.

Referring now more particularly to FIGS. 48, there is shown therein one form of sprinkler head 20 embodying the principles of the present invention. The sprinkler head 20 includes, in general, a swivel and spring brake assembly, generally indicated at 22, which is adapted to be connected at its lower end with the riser pipe 18. A sprinkler body, generally indicated at 24, is connected with the upper end of the swivel and spring brake assembly in hydraulic communication with the riser pipe 18 for directing the flow of water upwardly and outwardly, the swivel and spring brake assembly 22 mounting the sprinkler body for controlled rotational movement about a generally vertical axis. The sprinkler body 24 directs the water under pressure communicated therewith in a stream flowing therefrom in generally symmetrical relation to a plane passing through the axis of rotation.

An impulse arm assembly, generally indicated at 26, is pivotally mounted on the sprinkler body for oscillatory movement about an axis extending transverse to the aforesaid plane. The impulse arm assembly 26 includes a reactant element, generally indicated at 28, on the outer end thereof and is normally biased into a limited position wherein the reactant element 28 is disposed within the path of a stream issuing from an outlet nozzle 29 of the sprinkler body. The reactant element 28 is operable in response to the energy of a stream issuing from the outlet nozzle to effect movement of the arm through repeated oscillatory cycles, each of which includes an impulse stroke wherein the reactant element leaves the stream and moves away from the latter in one direction and a return stroke wherein the reactant element movesin the opposite direction toward the stream and enters the latter. The reactant element 28 is also operable during the portion of each oscillatory cycle when it is disposed within the stream to impart an incremental rotational movement to the sprinkler head which is controlled by the swivel and spring brake assembly 22.

The sprinkler head 20 also includes a reversing arm assembly, generally indicated at 30, which is pivotally mounted on the sprinkler body for oscillatory movement about an axis extending transverse to the aforesaid plane and which, preferably, is concentric with the pivotal axis of the impulse arm assembly 26. The reversing arm assembly 30 also includes a reactant element 32 on the outer end thereof and is normally biased into a limited position wherein the reactant element 32 is disposed out of the path of a stream issuing from the outlet nozzle 29. The reversing arm assembly 20 is operable to rotate the sprinkler head in the opposite direction and in order to accomplish this operation, there is provided a reversing arm actuating mechanism, generally indicated at 34, which is operable in response to the, sprinkler body reaching a first predetermined position in its operative rotation to effect a pivotal movement of the reversing arm assembly from its normally biased position into a position wherein the reactant element 32 is engaged by the stream issuing from the sprinkler body and maintained thereinby the stream against its normal bias. The reversing arm actuating mechanism 34 is operable, in response to the reversing rotational movement of the sprinkler body into a second predetermined position, to effect a pivotal movement of the reversing arm-assembly 30, back into its normally biased position wherein the reactant element 32 is disposed out of the path of the stream.

Except for certain changes in the reversing arm actuating mechanism 34, hereinafter to be more fully described, the constructional details and specific mode of operation of the structure of the sprinkler head 20 described above are in accordance with the disclosure contained in commonly-assigned co-pending application Ser. No. 823,026 filed May 8, 1969, now 1.8. Pat No. 3,559,087 in the name of Larry P. Meyer. A specific disclosure of these details of structure and operation is not believed essential to an understanding of the present invention, however the disclosure of the aforesaid Meyer application is hereby incorporated by reference into the present disclosure and it may be resorted to if necessary for such details.

As best shown in FIGS. 4-6, the reversing arm actuating mechanism 24 preferably includes a lever arm 36', the upper end of which is integrally formed on the hub portion of the reversing arm assembly 30 and the lower end of which is apertured to receive a pivot pin 38. The pivot pin also extends through a clevis 40 which is connected to the outer end of an elongated connecting rod 42. The inner end of the connecting rod 42 is bent transversely and pivotally engaged, as indicated at 44, within an apertured boss formed on one leg of a generally U-shaped yoke-like lever 46. As best shown in FIG. 4, the legs of the lever 46 embrace the upper end of the elbow member of the sprinkler head body, the upper extremities thereof being apertured to receive a pivot pin 48 which also extends through an apertured boss 50 rigidly formed on the upper end portion of the sprinkler body. The lower extremity of the lever 46 is provided with a cam roller 52 which is adapted to cooperate with a cam assembly, generally indicated at 54.

The cam assembly 54 determines movements of the reversing arm mechanism 30 during each operating cycle of the sprinkler body. The movements of the reversing arm mechanism determine the period of reverse movement in each cycle as well as changes in the distribution pattern in each cycle by a stream diffusing member 56. The member 56 is mounted on the outer end of an extention member 58 having its inner end secured to the reversing arm adjacent the reactant element 32, as by a pair of bolts or the like 60 extending through a flange 62 formed on the inner end of the extension member 58 and threadedly engaged within the mounting arm adjacent its juncture with the reactant element 32.

Referring now more particularly to FIGS. 4 and 7, the cam assembly 54 includes a horizontally extending arcuate wall or base 64 having an arcuate mounting wall or flange 66 extending downwardly from the inner periphery thereof and a spaced outer arcuate wall or flange 68 extending downwardly from the base 64. The spaced arcuate flanges 66 and 68 are adapted to engage over a fixed upwardly extending annular flange 70 (indicated at 222 in the aforesaid Meyer application) provided by the swivel and spring brake assembly 22. The arcuate flanges 66 and 68 thus serve to mount the cam assembly 54 for adjustable movement about the axis of rotation of the sprin-' kler head 20. Any suitable means may be provided for securing the base 64 in any-desired position of rotational adjustment and as shown, a pair of bolts 72 is threadedly engaged within the outer arcuate flange 68 so that when tightened the base 64 is fixedly secured to the flange 70.

Extending upwardly and inwardly at an angle corresponding to the angular inclination of the axis of the cam follower roller 52 is an arcuate wall 74. The arcuate wall provides a cam roller engaging cam surface including an elongated central arcuate surface 76 and

inclined surfaces

78 and 80 at the ends thereof.

Pivotally mounted on the end of the base 64 adjacent the end cam surface 80, as by a pivot pin 82, is a gate member 84 in the form of a bell crank lever. The gate member includes a first lever arm which extends from the pivot pin 82 in a direction generally toward the end cam surface 80 and is provided with an arcuate slot defining an outer cam surface 86 and an inner cam surface 88. The gate member also includes a second lever arm providing an outer cam surface 90. Formed on the base member 64 adjacent the end cam surface 78 is an inclined wall 92 defining an outwardly facing cam surface 94.

OPERATION OF THE SPRINKLER HEAD OF FIGS. 4 7

The cam assembly 54 of the reversing arm actuating mechanism 34 is operable to effect repeated operating cycles of the sprinkler head 20, each of which includes an operative step-by-step incremental rotational movement of the sprinkler body 24 under the action of the impulse arm mechanism 26 through an arcuate extent of more than 360 but less than 720 (e.g., 450), and a return movement under the action of the reversing arm mechanism 30 through an arcuate extent equal to the operative movement less 360 (e.g., 90). For convenience, the operating cycle will be described beginning with the sprinkler body in a position just prior to the engagement of the cam roller 52 with the cam surface 78. In this position, the impulse arm mechanism 26 is operable as a result of its repeated oscillatory cycles to effect a step-by-step incremental rotational movement of the sprinkler head in a clockwise direction as viewed in FIG. 7. The reversing arm mechanism 30 is disposed in its inoperative limiting position as shown in FIGS. 4 and 5 and in solid lines in FIG. 6. It will also be noted that the stream diffusing member 56 is disposed within the path of the stream issuing from the outlet nozzle 29.

During the initial operative movement, cam roller 72 will engage the cam surface 78 of the cam assembly 54 which has the effect of pivotally moving the lever 46 in a clockwise direction, as viewed in FIG. 4, which, in turn, will effect a clockwise movement of the reversing arm, through the lever arm 36 and connecting rod 42, from its inoperative limiting position into an intermediate position as shown in phantom lines in FIG. 6. In this intermediate position, both the reactant element 32 and the stream diffusing member 56 are disposed out of the path of the stream issuing from the outlet nozzle 29. During the next operative movement of the sprinkler body for an arcuate extent of approximately 90, the reversing arm mechanism 30 is maintained in its intermediate position by the engagement of the cam roller 52 with the arcuate cam surface Assuming that the gate member 84 is disposed in the dotted line position shown in FIG. 7, the cam roller 52 will move past the first lever arm of the gate member and into engagement with the end cam surface 80 permitting the reversing arm mechanism 30 to be spring urged into its inoperative limiting position. During the next approximately 270 of rotational operative movement, the reversing arm mechanism 30 is resiliently maintained in its inoperative limiting position wherein the stream diffusing member 56 is disposed in the path of the stream. During the initial portion of this movement the cam roller 52 will engage the cam surface 90 on the second arm of the gate member 84 and effect a clockwise pivotal movement of the gate member 84, as viewed in FIG. 7, from its dotted line position into its full line position.

At the end of this 270 operative movement, the cam roller 52 will again engage cam surface 58 so as to move the reversing arm mechanism 30 back into its intermediate position. However, at the end of the next 90 of rotational movement, cam roller 52 will now engage the outer cam surface 86 of the gate member 84 so that during subsequent movement the cam roller will be moved radially inwardly with respect to the axis of rotation of the sprinkler arm which, in turn, through the lever 46, connecting rod 42 and lever arm 36 will move the reversing arm mechanism 30 into its operative position, as shown in dotted lines in FIG. 6. In this operative position, the reactant element 32 is disposed within the path of the stream issuing from the outlet nozzle 29 and the stream diffusing member 56 is disposed out of the path of the stream. As soon as the reversing arm mechanism 30 is moved into its operative position, the sprinkler head will be rotated in a counterclockwise direction, as viewed in FIG. 7, with a continuous rapid movement. The reaction of the stream on the reactant element 32 serves to maintain the reversing arm mechanism 30 in its operative position during this reverse movement against its resilient bias.

During the initial part of this reverse movement, the cam roller 52 will engage the inner cam surface 88, thus effecting a pivotal movement of the gate member 84 in a counterclockwise direction, as viewed in FIG. 7, from the solid line position to the dotted line position shown. At the end of the reverse movement cam surface 94 will be engaged by the cam roller 52 so as to effect a radially outward movement of the cam roller which, in turn, through the lever 46, connecting rod 42 and lever arm 36, moves the reversing arm mechanism from its operative position back into its intermediate position. Thus, at the end of the reverse movement the cam roller 52 is disposed in engagement with the end of the arcuate cam surface 76 adjacent the cam surface 78 and a new cycle is then commenced.

It will be understood that the operation of the reactant element 28 of the impulse arm mechanism 26 is such that it engages only a minor portion of the stream flowing from the outlet nozzle 29 so that a major portion of the stream is unobstructed by the cycling of the impulse reactant element 28. When the stream is otherwise unobstructed by the stream diffusing member 56, as when the reversing arm mechanism is disposed in its intermediate or operative position, the water flowing from the outlet nozzle 29 will be distributed with a distribution pattern which is maximum adjacent the periphery of the pattern area and decreases toward the axis of rotation of the sprinkler head 20. This distribution pattern is a composite of a conventional doughnut distribution pattern (due to the unobstructed major portion of the flow), and a conventional elliptical distribution pattern (due to the cyclical obstruction by the reactant element 28 of the minor portion of the flow).

On the other hand, when the stream diffusing member 56 is disposed within the path of stream issuing from the outlet nozzle 29, as when the reversing arm mechanism 30 is disposed in its inoperative limiting position, the flow of water is continuously diffused or broken up so as to be distributed within the pattern area with a distribution pattern which is maximum adjacent the axis of rotation of the sprinkler head and decreases toward the periphery of the pattern area. The stream diffusing member 56 thus converts the distribution pattern from a composite doughnut and elliptical pattern to an elliptical pattern.

From the description of the cam assembly 54 set forth above, it will be apparent that during the operative movement of each operating cycle, the stream diffusing member 56 will be disposed within the path of the stream during the 270 arcuate movement wherein the cam roller 52 is out of contact with the cam assembly 54 and will be out of the path of the stream during the two operative movements wherein the cam roller 52 is in engagement with the cam surface 76 of the cam assembly 54. The water distribution obtained by the sprinkler head 20 will thus be as shown by the shade lines in FIG. 8.

Referring now more particularly to FIGS. 9-11, there is shown therein a modified form of a sprinkler head, generally indicated at 20, embodying the principles of the present invention. The sprinkler head 20 includes a sprinkler body assembly 134 and a bearing and seal assembly 136 for connecting the sprinkler body assembly in communicating relation with a riser pipe 18. The bearing and seal assembly 136 also serves to support the sprinkler body assembly 134 for rotational movement about an upright or vertical axis.

The sprinkler head 20 also includes an impulse arm mechanism, generally indicated at 138, whichis operable, when the sprinkler body assembly 134 is communicated through the bearing and seal assembly 136 with a source of water under pressure, to effect a step-by-step rotary movement of the sprinkler body assembly about its rotational axis in one direction.

The sprinkler head 20' also includes a reversing mechanism, generally indicated at 140, which is operable when the sprinkler body assembly 134 has been moved into a predetermined position of rotation by the impulse arm assembly 138, to effect a rapid step-by-step incremental pivotal movement of the sprinkler body assembly in the opposite direction from the first-mentioned predetermined position into a second predetermined position.

The sprinkler head also includes a stream diffusing mechanism, generally indicated at 142, which is operable during each operating cycle of the sprinkler head to change the distribution pattern of the water flowing from the sprinkler head onto its pattern area.

Referring now more particularly to FIG. 9, the sprinkler body assembly 134 includes a main casting or body having a lower inlet portion 144 defining a water inlet passage 146 therein. Extending upwardly and outwardly from the inlet portion 144 at an angle of approximately with respect to the vertical is a first lower outlet portion 148 having a water outlet passage 150 therein which communicates at its lower end with the inlet passage 146 and at its outer end with a nozzle member 152 threadedly engaged within the outer end of the outlet portion 148.

Extending upwardly and outwardly from the inlet portion 144 at an angle of approximately 25 with respect to the vertical is a second upper outlet portion 154 parallel with the outlet portion 148. The outlet portion 154 like the outlet portion 148, includes an outlet passage 156 which communicates at its lower end with the inlet passage 146 and its outer end with a nozzle member 158 threadedly engaged within the outer end of the outlet portion 154. The axes of the

outlet passages

150 and 156 and the axis of the inlet passage 146 are all disposed within a common vertical plane so that the streams issuing from the

nozzles

152 and 158 are directed upwardly and outwardly in generally the same direction in symmetrical relation to the common plane.

The bearing and seal-assembly 136 includes an inner tubular member 160 having its upper end exteriorly threaded, as indicated at 161, to engage interior threads formed on the lower end of the inlet portion 144 of the sprinkler body assembly 134. The lower end of the tubular member 160 is provided with an annular flange 162 which extends radially outwardly therefrom. Journalled on the central outer peripheral portion of the tubular member 160 is a riser pipe connecting member 164, the lower outer periphery of which is threaded, as indicated at 166, for engagement within cooperating interior threads formed in the upper end of the riser pipe 138.

A lower seal assembly in the form of a pair of outer rubber washers 168 and an inner Teflon washer 170 is mounted on the inner tubular member 160 between the annular flange 162 thereof and the lower end of the member 164. A coil spring 172 mounted in surrounding relation to the upper end of the inner tubular member 160 between the lower end of the sprinkler body inlet portion 144 and the upper end of the member 164 serves to resiliently maintain the

washers

168 and 170 in engagement between the

members

160 and 164. Preferably, an upper sealing assembly including an upper rubber washer 174 and a lower Teflon washer 176 is mounted between the lower end of the spring 172 and the upper end of the member 164.

It can be seen that the member 164 is thus fixedly supported on the upper end of the riser pipe 18 and the sprinkler body assembly 134 is rotatably supported within the member 164 by virtue of its fixed connection with the tubular member 160. The spring 172 and sealing

washers

168, 170, 174 and 176 provide a controlled frictional resistance to the rotation of the sprinkler body and at the same time efiectively seal the water under pressure flowing from the riser pipe 138 through the tubular member 160 and into the sprinkler body 134.

As shown, the impulse arm mechanism 138 is of generally conventional construction and includes an arm structure 178 having a cylindrical portion 180 extending upwardly from the central portion thereof which is formed with a throughbore 182, to receive a shaft or pin 184. The pin 184 has its lower end fixedly engaged within a bore 186 formed in the upper central portion of the sprinkler head body 134 to thus support the impulse arm 178 for pivotal movement about the axis of the pin. As shown, the axis of the pin 178 is coincident with the axis of the inlet passage 146 and the axis of rotation of the sprinkler body assembly 134.

Extending upwardly from the upper outer end of the outlet portion 148 is an integral impact bridge portion 188 which is adapted to be engaged by an adjacent portion of the impulse arm 178. The bridge portion 188 includes an integral horizontally extending pin mounting portion 190 which is centrally apertured, as at 192, to receive the upper end of the mounting pin 184. A coil spring 194 is mounted in surrounding relation to the cylindrical portion 180 of the impulse arm 178 and has its upper end connected to the mounting portion 190 and its lower end connected with the central portion of the impulse arm 178 so as to resiliently bias the impulse arm in a direction to maintain the arm in engagement with the impact portion 188.

The end of the impulse arm adjacent the outlet nozzle 152 is provided with a stream engaging spoon or reactant element, indicated at 196. The spoon includes an inner portion 198 having a stream engaging surface which is disposed in a direction such that when the stream impinges thereon the reaction force of the stream acts in a direction to move the impulse am into engagement with the impact portion 188. The stream engaging surface of the inner portion 198 is inclined in a direction to direct the stream engaged thereby to a generally oppositely facing outer stream engaging surface provided on a spaced outer portion-200 which is shaped and positioned so that when the stream engages the same, the reaction force thereon will act in a direction to move the impulse arm 178 away from the impact portion 188.

The operation of the impulse arm mechanism 138 is conventional in nature. Briefly, it can be seen that since the reaction force acting on the outer portion 200 acts through a greater lever arm than the reaction force on the inner portion 198, the impulse ann 178 will be moved about its axis in a direction away from the impact portion 188. During this impulse movement, the spring 194 is stressed until the pivotal movement of the impact arm is completely arrested at which time the spring 194 serves to effect a pivotal movement of the impulse arm in a direction toward the impact portion 188. During the latter portion of this return movement the stream issuing from the nonle 152 will first engage the inner portion 198 which acts in a direction to move the impulse arm in a direction to engage the latter with the impact portion 188. When the impulse arm 178 impacts or engages the impact portion 188, the sprinkler head assembly will be moved incrementally a predetermined arcuate distance under the frictional control of the bearing and seal assembly 136.

In accordance with conventional practice, the opposite end of the impulse arm 178 is provided with a counterbalancing portion 202 which is of a shape and size to provide both weight and wind resistance balance to the impulse arm.

The reversing mechanism includes a pair of '

coacting rocker elements

204 and 206 mounted in vertically spaced relation on a depending pivot pin 208, having its upper end fixedly engaged within a boss 210 formed integrally on the sprinkler body in a position oppositely outwardly of the outlet portion 154. Rocker element 204 includes arms which embrace the sprinkler body, and therefore limit the pivotal movement of the rocker element 204 about the pivot pin 208. Extending upwardly from one arm of the rocker element 204 is a stop lug 212 which is adapted to cooperate with a depending lug 214 formed integrally on the'adjacent portion of the impulse am 178.

The rocker element 204 in the limiting position shown in FIG. 9 is disposed so that the lug 212 is out of the path of movement of the lug 214, thus permitting the impulse arm mechanism 138 to function in its normal manner as indicated above. When the rocker element 204 is moved into its other limiting position, the lug 212 is disposed within the path of movement of the lug 214 so as to be engaged during each oscillating cycle of the impulse arm mechanism 132 and thus effecting a rapid step-by-step incremental movement of the sprinkler head in a direction opposite to the direction of operative movement under the normal operation of the impulse arm mechanism 138.

The rocker element 204 is moved between its limiting positions in response to the movement of the lower rocker element 206. In this regard, it will be understood that the two rocker elements are interconnected by an over-center spring 216 of generally conventional construction. The rocker element 206 likewise includes a pair of outwardly extending arms which embrace the central portion of the sprinkler body so as to limit its pivotal movement. Formed on the central portion of the rocker element 206 is a depending boss 218 within which the upper end of an actuating pin 220 is fixedly mounted.

The lower end of the actuating pin is adapted to be selectively engaged by a pair of

adjustable elements

222 and 224. As best shown in FIG. 9, each of the

elements

222 and 224 is preferably constructed of a'metal rod of circular cross-section having a major portion thereof bent into a generally circular configuration of a size and shape to engage around an upper cylindrical peripheral portion 226 of the member 164. As shown, the circular portions are mounted on the cylindrical portion 226 with a washer 228 disposed therebetween and each element includes a relatively short end portion extending generally radially outwardly from the respective circular portion in a position to be engaged by the lower end of the actuating pin 220. In order to retain the

elements

222 and 224 in their selected positions of operation, a nut 230 is threadedly engaged with the upper end of the cylindrical portion 226. It will be understood that by tightening the nut 230, the

elements

222 and 224 will be clamped and maintained in the position of adjustment to which they have been selectively moved. In general, both the construction and the operation of the reversing mechanism 140 are conventional in nature.

The stream diffusing mechanism 142 is preferably in the form of a lever including a mounting arm 232 having a stream diffusing element or member 234 mounted on one end thereof. The mounting arm 232 includes a pair of vertically spaced lugs 236 extending transversely from the opposite end thereof which lugs are adapted to embrace a boss 238 formed integrally on the sprinkler body and extending outwardly from the adjacent part of the outlet portion 154. A pivot pin 239 is engaged within corresponding vertical apertures in the boss 238 and lugs 236 so as to mount the arm for pivotal movement about a vertical axis between an operative position wherein the member 234 is disposed within the stream issuing from outlet nozzle 158 and an inoperative position wherein the member 234 is disposed out of the path of the stream.

The mounting arm 232 is moved between its two positions by an integral arm 240 which extends downwardly and then outwardly from the inner end of the arm 232. The outer end of the arm 240 is provided with a boss 242 within which the upper end of an actuating pin 244 is mounted. The lower end of the pin 244 constitutes a cam follower element which is adapted to cooperate with a cam plate, generally indicated at 246.

The cam plate 246 includes a hub portion 248 which is adapted to engage over a cylindrical portion of the member 164 disposed below the lower stop element 224. Any suitable means may be provided for securing the cam plate in a desired position of rotational adjustment, as for example, a set screw 250, as shown in FIG. 9. The portion of the cam plate extending outwardly of the hub portion 248 is formed with an annular cam groove including a relatively short inner portion 252 and an outer portion 254, as shown in FIG. 10.

OPERATION OF THE SPRINKLER HEAD OF FIGS. 9 11 Each operating cycle of the sprinkler head includes an operative step-by-step incremental movement of the sprinkler body about its axis of rotation under the operation of the impulse arm mechanism 138. The extent of this movement is dependent upon the setting of the

stop elements

222 and 224. In the embodiment shown, the operative movement has an arcuate extent of approximately 270. The operating cycle also includes a reverse more rapid step-by-step incremental movement in the opposite direction under the cooperating action of the reversing mechanism 140 and impulse arm mechanism 138. The reverse movement is of an arcuate extent equal to the arcuate extent of the operative movement.

The stream diffusing mechanism 142 is operative to change the distribution pattern of the stream flowing from the outlet nozzle 158 from an elliptical pattern during a first portion of the operative movement as, for example, an extent of approximately to a doughnut shaped distribution pattern through a central or intermediate portion of the operative movement, as for example, an arcuate extent of approximately 90 and then back to an elliptical distribution pattern for the remaining portion of the operative movement.

It will be understood that this change is accomplished by the operation of the cam plate 246 in effecting the movement of the stream diffusing member 234 between its positions into and out of the path of the stream issuing from the outlet nozzle 158. It can be seen that when the actuating pin 244 is engaged within the outer portion 254 of the cam groove of the cam assembly 246, the stream difiusing member 234 will be within the path of movement of the stream flowing from the outlet nozzle 58. By virtue of the continuous interruption or diffusion of this stream the water flowing from the outlet nozzle 158 will be distributed within the adjacent portion of the pattern area of the sprinkler head with an elliptical distribution pattern. That is, the distribution pattern is maximum adjacent the axis of rotation of the sprinkler head and decreases toward the periphery. When the inner portion 252 of the cam groove is encountered during the operative movement of the sprinkler head, the actuating pin 244 is moved radially inwardly with respect to the axis of rotation of the sprinkler head. This movement causes the stream diffusing member to move out of the path of the stream issuing from the outlet nozzle 158 by virtue of the pivotal action provided by the pivot pin 239. Thus, during this portion of the operative movement of the sprinkler body, the. water flowing from the outlet 158 is relatively unobstructed and is distributed with a doughnut shaped pattern, that is, a distribution pattern which is maximum adjacent the periphery and decreases toward the axis of rotation of the sprinkler head. It will also be noted that during the reverse movement the distribution pattern of the stream flowing from the outlet nozzle 158 will be changed in a comparable manner.

The distribution pattern of the water flowing from the outlet noule 152 will be elliptical, that is, maximum adjacent the sprinkler head and decreasing toward the periphery. However, since this outlet is of a size smaller than the size of the outlet nozzle 158, the composite distribution curve during the movement when the outlet nozzle 158 is unobstructed is a maximum adjacent the periphery, decreasing toward the axis of the sprinkler head at a rate somewhat less than the rate of a conventional doughnut pattern. From the above it can be seen that the distribution from the sprinkler head 20 will be as indicated by the shade lines in FIG. 12.

OPERATION OF THE PIVOT MOVE AGRICULTURAL IRRIGATION SYSTEM As previously indicated, approximately 12 of the penultimate sprinkler heads adjacent the outer end of the conduit assembly 12 are preferably of the construction of the form indicated above at 20 or 20'. Where the sprinkler heads 20 are utilized, the cam assembly 54 is adjusted, as by the bolts 72, so that the central portion of the cam surface 76 will be engaged by the cam roller 52 when the outlet nozzle 29 is directed forwardly with respect to the direction of movement of the conduit assembly 12. Thus, the distribution of each individual sprinkler head 20 is oriented within the sprinkler head pattern area so that the relatively unobstructed portion of the water distribution is oriented within the forward portion of the sprinkler head pattern area. With reference to FIGS. 1 and 8, this orientation is equivalent to transferring the pattern of FIG. 8 I

onto the pattern of FIG. 1 without any substantial change in the angular orientation thereof.

With the above in mind it will be understood that during each operating cycle water is distributed to the 90 forwardly facing segmental area through two operative movements and one return movement to each single movement through the remaining 270 portion of the operating cycle. Thus, during each operating cycle more water is distributed to the forward portion of the sprinkler head pattern area than to the rearward portion thereof, the ratio being slightly more than 1.5 to 1. Thus, this ratio represents the ratio of the average application rate distributed to the forward portion of the sprinkler head pattern area and the rearward portion thereof.

Moreover, it will be noted that the distribution curve considered along the axis of any one sprinkler head 20 in the direction of movement from the leading edge portion of the sprinkler head pattern area to the trailing edge portion thereof rises sharply to a maximum adjacent the leading edge portion decreasing somewhat to the axis of the sprinkler head and then following an elliptical pattern to the trailing end thereof. It can thus be seen that by utilizing a plurality of sprinkler heads 20 in the manner indicated above, the distribution within the associated part of the sprinkler head pattern area of the pivot move system will be in accordance with the principles of the aforesaid Sisson and Hanson patent application. Moreover, since the distribution within the 90 segmental area on each side of the central segmental area as well as the rearward 90 segmental area has an elliptical pattern a greater uniformity in a direction longitudinally throughout the adjacent sprinkler head pattern area is obtained as a result of the overlapping of the individual pattern areas of the individual sprinkler heads 20.

Where the sprinkler heads 20' are utilized, it will also be seen that the distribution is likewise within the principles of the aforesaid Sisson and Hanson application. When the sprinkler heads 20' are utilized, the

stop elements

222 and 224 are adjusted so that the operative and return movements will be through an arcuate extent of approximately 270. The cam plate 246 is adjusted so that the 90 inner cam groove portion 252 will be engaged during the central portion of the operative and return movements. Both of these adjustments are oriented with respect to the direction of movement of the conduit assembly 12 so that the central portion of the cam groove 252 is engaged by the actuating pin 244 when the outlet nozzle 158 extends forwardly with respect to the direction of movement. Such an orientation would be equivalent to transposing the distribution of FIG. 12 to an individual pattern area of FIG. 1 without any angular displacement.

With this orientation it will be noted that because of the overlapping of the individual pattern areas of the sprinkler heads 20, a lesser amount of the individual pattern areas is overlapped in the trailing or rearward portion of the sprinkler head pattern area than in the forward portion thereof. Thus, there is a greater increase in the trailing portion of the sprinkler pattern area than in the forward portion thereof because of overlap. Consequently, the average application rate in the forward portion is greater than the average application rate in the rearward portion. The ratio in the embodiment shown is equal to slightly less than 1.5 to I.

By virtue of the doughnut shaped distribution pattern of the water flowing from each outlet nozzle 158 during its operative and return movements through the 90 forward segmental pattern area, the distribution curve taken along the axis of any one sprinkler head in the direction of movement of the conduit assembly will rapidly increase to a maximum adjacent the leading edge portion of the sprinkler head pattern and then decrease toward the axis. The distribution rearwardly of the axis will be elliptical.

Again it will be noted that the 90 segmental portions of each individual pattern area on opposite sides of the central segmental pattern area have an elliptical distribution, thus tending to more uniformly distribute the water due to overlap in a direction parallel to the longitudinal extent of the conduit assembly. While some non-uniformity is introduced as a result of no distribution of water to the rearwardly facing 90 segmental area associated with each sprinkler head 20', by the same taken, the maximum accumulated application rates in the rearward portion of the sprinkler head pattern area are minimized.

It will be understood that the distribution can be varied from the preferred embodiment described above in connection with both the

sprinkler head

20 and 20. For example, the cam assembly 54 could be readily modified to encompass a forward pattern area of from 60 to 120. Moreover, as suggested by the form of the sprinkler head 20', the stream diffusing member 56 could be mounted on an arm independent of the reversing arm so that the pattern area where the nozzle is substantially unobstructed could be varied to an arcuate extent difi'erent from the arcuate extent of the reversing movement. This same relationship can be obtained by varying the relative arcuate positions of the gate member 84 and the cam surface 94 with respect to the arcuate extent of the cam surface 76.

With respect to the sprinkler head 20, it will be readily understood that the operative and return movements can be varied within a range of the order of between 240 to 300. Likewise, the cam plate can be modified to provide an unobstructed flow through an arcuate extent within a range of the order of between 60 to 120. Moreover, it is within the contemplation of the present invention to provide a sprinkler head of the type disclosed in the aforesaid Sisson and Hanson application with a stream diffusing mechanism, such as the mechanism 142.

It thus will be seen that the objects of this invention have been fully and effectively accomplished. It will be realized, however, that the foregoing specific embodiment has been shown and described only for the purpose of illustrating the principles of this invention and is subject to extensive change without departure from such principles.

What is claimed is:

1. In a pivot move agricultural irrigation system for distributing a source of water under pressure onto a field made up of soil having the capability of receiving water without appreciable surface run-off at a relatively high average application rate when relatively dry and at a relatively low application rate when relatively saturated with water including elongated conduit means for receiving a source of water under pressure at one end and conveying the water under pressure in a generally horizontal direction toward the opposite end thereof, a series of step-by-step rotary sprinkler heads spaced longitudinally along said conduit means in communicating relation therewith for distributing water under pressure within said conduit means incrementally onto the field in stepbystep rotary fashion within overlapping individual pattern areas defining a predetermined sprinkler head pattern area having first and second portions disposed on opposite sides of said conduit means, and means for supporting said conduit means above and generally parallel with the surface of the field and for effecting an arcuate movement of said conduit means about an axis adjacent said one end thereof in a direction toward said first pattern area portion along a predetermined circular path in the field while said conduit means is communicated with a source of water under pressure to distribute the same onto the field through said series of sprinkler heads within a predetermined system pattern area substantially greater than said predetermined sprinkler head pattern area by progressively moving the position of said predetermined sprinkler head pattern area within said predetermined system pattern area in said direction, at least a plurality of said series of sprinkler heads adjacent the opposite end portion of said conduit means having means for distributing the water under pressure within the longitudinally adjacent portion of said conduit means to the first pattern area portion covered thereby with an average application rate which is higher than the average application rate in said second portion covered thereby by a ratio of the order of between 1.3 to 1 and 4.0 to l and with a variation in the application rate within the first pattem area portion covered thereby such that the distribution pattern increases rapidly adjacent the leading portion of the sprinkler head pattern area covered to an extent sufficient to insure that the maximum accumulated application rate is applied to the soil while in a relatively dry condition, thus minimizing the creation of appreciable surface run-ofl', the improvement which comprises said water distributing means in each of said plurality of sprinkler heads comprising a sprinkler body having an inlet and outlet means, means for mounting said sprinkler body for controlled rotational movement about a generally vertical axis with said inlet in communication with said conduit assembly, said outlet means being disposed to direct water under pressure communicated with said inlet in generally one direction upwardly and outwardly in generally symmetrical relation to a plane passing through the axis of rotation, means for effecting repeated operating cycles of said sprinkler body including an operative movement in one direction about its axis and a reverse movement in the opposite direction about its axis such that the water flowing through said outlet means will be applied to an individual pattern area including a semi-circular portion disposed within the first portion of said sprinkler head pattern area and a remaining portion disposed within the second portion of said sprinkler head pattern area, said semi-circular portion including a central segmental area of an arcuate extent of the order of between 60 to 120, said cycling means including an impulse arm pivotally mounted with respect to said sprinkler body for oscillatory movement and having a reactant element thereon, said impulse arm being normally biased into a limited position wherein said reactant element is disposed to engage a portion of the water flowing through said outlet means and having means thereon operable l) in response to the energy of the water flowing from said outlet means engaged by said reactant element to move said arm through repeated oscillatory cycles each of which includes an impulse stroke wherein said reactant element leaves the flowing water and moves away from the latter in one direction and a return stroke wherein said reactant element moves in the opposite direction toward the flowing water and enters the latter, and (2) during each oscillatory cycle thereof to effect controlled incremental rotational movement of said sprinkler body in the direction of operative movement, the operating cycle being such that the arcuate extent of said operative movement during which the water flowing from said outlet means is distributed within the semicylindrical portion of said individual pattern area is greater than the arcuate extent of the operative movement during which the water flowing from said outlet means is distributed to the remaining portion of said individual pattern area so that during one cycle of operation said semi-circular portion receives a greater amount of water than said remaining portion by a ratio of the order of between 1.3 to l and 4.0 to l, the frequency of said oscillatory cycles and the relative portion of the water flowing from said outlet means engaged by said reactant element being such that the water flowing from said outlet means during the operative movement is normally distributed with a distribution pattern which is maximum adjacent the periphery thereof and decreases toward the axis of said sprinkler, and means operable during the operative movement of each operating cycle for engaging the water flowing from said outlet means so as to modify the distribution throughout said pattern area except within said segmental area to a distribution pattern which is maximum adjacent the axis of the sprinkler body and decreases toward the periphery. 2. The improvement as defined in claim 1 wherein said individual pattern area is of an arcuate extent of 360 and said operating cycle consists of an operative movement through an arcuate extent equal to 360 plus the arcuate extent of said segmental area and a reverse movement through an arcuate extent equal to that of said se mental area.

3. The improvement as de med in claim 1 wherein said individual pattern area is of an arcuate extent of the order of between 240 and 300 and said operating cycle consists of an operative movement throughout the arcuate extent of said individual pattern area and a reverse movement throughout the arcuate extent of said individual pattern area.

Claims

1. In a pivot move agricultural irrigation system for distributing a source of water under pressure onto a field made up of soil having the capability of receiving water without appreciable surface run-off at a relatively high average application rate when relatively dry and at a relatively low application rate when relatively saturated with water including elongated conduit means for receiving a source of water under pressure at one end and conveying the water under pressure in a generally horizontal direction toward the opposite end thereof, a series of step-by-step rotary sprinkler heads spaced longitudinally along said conduit means in communicating relation therewith for distributing water under pressure within said conduit means incrementally onto the field in step-by-step rotary fashion within overlapping individual pattern areas defining a predetermined sprinkler head pattern area having first and second portions disposed on opposite sides of said conduit means, and means for supporting said conduit means above and generally parallel with the surface of the field and for effecting an arcuate movement of said conduit means about an axis adjacent said one end thereof in a direction toward said first pattern area portion along a predetermiNed circular path in the field while said conduit means is communicated with a source of water under pressure to distribute the same onto the field through said series of sprinkler heads within a predetermined system pattern area substantially greater than said predetermined sprinkler head pattern area by progressively moving the position of said predetermined sprinkler head pattern area within said predetermined system pattern area in said direction, at least a plurality of said series of sprinkler heads adjacent the opposite end portion of said conduit means having means for distributing the water under pressure within the longitudinally adjacent portion of said conduit means to the first pattern area portion covered thereby with an average application rate which is higher than the average application rate in said second portion covered thereby by a ratio of the order of between 1.3 to 1 and 4.0 to 1 and with a variation in the application rate within the first pattern area portion covered thereby such that the distribution pattern increases rapidly adjacent the leading portion of the sprinkler head pattern area covered to an extent sufficient to insure that the maximum accumulated application rate is applied to the soil while in a relatively dry condition, thus minimizing the creation of appreciable surface run-off, the improvement which comprises said water distributing means in each of said plurality of sprinkler heads comprising a sprinkler body having an inlet and outlet means, means for mounting said sprinkler body for controlled rotational movement about a generally vertical axis with said inlet in communication with said conduit assembly, said outlet means being disposed to direct water under pressure communicated with said inlet in generally one direction upwardly and outwardly in generally symmetrical relation to a plane passing through the axis of rotation, means for effecting repeated operating cycles of said sprinkler body including an operative movement in one direction about its axis and a reverse movement in the opposite direction about its axis such that the water flowing through said outlet means will be applied to an individual pattern area including a semicircular portion disposed within the first portion of said sprinkler head pattern area and a remaining portion disposed within the second portion of said sprinkler head pattern area, said semi-circular portion including a central segmental area of an arcuate extent of the order of between 60* to 120*, said cycling means including an impulse arm pivotally mounted with respect to said sprinkler body for oscillatory movement and having a reactant element thereon, said impulse arm being normally biased into a limited position wherein said reactant element is disposed to engage a portion of the water flowing through said outlet means and having means thereon operable (1) in response to the energy of the water flowing from said outlet means engaged by said reactant element to move said arm through repeated oscillatory cycles each of which includes an impulse stroke wherein said reactant element leaves the flowing water and moves away from the latter in one direction and a return stroke wherein said reactant element moves in the opposite direction toward the flowing water and enters the latter, and (2) during each oscillatory cycle thereof to effect controlled incremental rotational movement of said sprinkler body in the direction of operative movement, the operating cycle being such that the arcuate extent of said operative movement during which the water flowing from said outlet means is distributed within the semi-cylindrical portion of said individual pattern area is greater than the arcuate extent of the operative movement during which the water flowing from said outlet means is distributed to the remaining portion of said individual pattern area so that during one cycle of operation said semi-circular portion receivEs a greater amount of water than said remaining portion by a ratio of the order of between 1.3 to 1 and 4.0 to 1, the frequency of said oscillatory cycles and the relative portion of the water flowing from said outlet means engaged by said reactant element being such that the water flowing from said outlet means during the operative movement is normally distributed with a distribution pattern which is maximum adjacent the periphery thereof and decreases toward the axis of said sprinkler, and means operable during the operative movement of each operating cycle for engaging the water flowing from said outlet means so as to modify the distribution throughout said pattern area except within said segmental area to a distribution pattern which is maximum adjacent the axis of the sprinkler body and decreases toward the periphery.

2. The improvement as defined in claim 1 wherein said individual pattern area is of an arcuate extent of 360* and said operating cycle consists of an operative movement through an arcuate extent equal to 360* plus the arcuate extent of said segmental area and a reverse movement through an arcuate extent equal to that of said segmental area.

3. The improvement as defined in claim 1 wherein said individual pattern area is of an arcuate extent of the order of between 240* and 300* and said operating cycle consists of an operative movement throughout the arcuate extent of said individual pattern area and a reverse movement throughout the arcuate extent of said individual pattern area.