Abstract:
An irrigation sprinkler unit includes a tubular housing enclosing a speed reducing drive which is driven by a water actuated turbine wheel and rotates a rotary nozzle head at a substantially slower speed. The drive also rotates a tubular valve member within an annular valve body within the housing, and the valve member and valve body have cooperating radial ports which automatically and continuously vary the flow rate of water through the housing for continuously varying the radial distance of a water stream discharged from the nozzle head.

Description:
BACKGROUND OF THE INVENTION 
   In the art of rotary irrigation sprinklers, for example, of the pop-up type disclosed in U.S. Pat. Nos. 4,026,471, 4,773,595, 4,892,252, 4,971,250, 5,174,501 and 5,526,982, it has been found desirable to vary the flow rate of water flowing through the sprinkler and discharged from the nozzle head as it rotates to provide a more uniform radial distribution of water from the nozzle head, regardless of whether the water is discharged in a single stream from a single nozzle orifice or is discharged from multiple orifices in the nozzle head. Uniform radial distribution of water is desirable whether the water is being distributed in a full circular pattern or in a part circular pattern. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to an improved rotary irrigation or water sprinkler which may be of the pop-up type or a rotary sprinkler which does not have a pop-up nozzle head. The irrigation sprinkler of the invention provides for automatically varying the flow rate of water through the sprinkler and thereby automatically varying the radial distance the water is discharged from the nozzle head of the sprinkler unit as the head rotates. In accordance with a preferred embodiment, the sprinkler of the invention includes a tubular housing supporting a valve body enclosing a rotary valve member which is driven by the output shaft of a speed reducing drive having an input driven by a water activated rotary turbine wheel. The output shaft of the speed reducing drive or transmission also rotates the nozzle head of the sprinkler unit. The valve member rotates within the valve body, and radial ports within the valve member cooperate with radial ports within the surrounding valve body to provide the variable flow rate of water through the sprinkler unit and into the nozzle head. The size and shapes of the ports may be designed to provide the desired variable radial flow rate of water from the rotary nozzle head of the sprinkler unit. 
   Other features and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an axial section through a commercially available irrigation sprinkler unit modified in accordance with the invention; 
       FIG. 2  is an exploded view of an upper portion of the sprinkler unit shown in  FIG. 1  and modified in accordance with the invention; 
       FIG. 3  is an enlarged axial section of the upper portion shown in  FIG. 2 ; 
       FIG. 4  is a plan view of the annular valve body shown assembled in  FIG. 3 ; and 
       FIG. 5  is an axial section of the valve body, taken on the line  5 — 5  of  FIG. 4 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1 , pressurized water flows from a supply line or pipe (not shown) connected to the lower end portion  8  of an irrigation sprinkler unit  10  assembled with parts or components molded of plastic materials. The water flows upwardly within the tubular housing  12  and through a plastic filter screen  14  and then through diametrically opposed inclined jet openings  16  to start rotation of a turbine wheel  18 . The turbine wheel  18  drives a tubular input shaft  21  of a speed reducing unit or drive  25  having a tubular housing  26  within an internal spline or gear teeth forming part of a planetary gear train having a rotary output shaft  28  at the top of the sprinkler unit  10 . The detail construction of the speed reducing unit or drive  25  is disclosed in U.S. Pat. Nos. 5,662,545 and 5,785,248, issued to The Toro Company, and the disclosures of which are herein incorporated by reference. The housing  26  is spaced concentrically within the tubular housing  12  by axially extending ribs  32  molded as an integral part of the housing  26  and defining circumferentially spaced passages  34  extending from the bottom of the speed reducing unit  25  to the top of the unit, as shown in  FIG. 1 . 
   Referring to  FIG. 3 , the rotary output shaft  28  includes a tubular and cylindrical rotary valve member  35  which projects upwardly from an integral bottom flange portion  37  which carries an upper set of planetary gears  39  for the speed reducing unit  25 . A set of radial ports  42  are formed within a lower portion of the tubular valve member  35 , and a set of circumferentially spaced radial ports  44  are formed within an upper portion of the valve member  35 . The combined output shaft  28  and valve member  35  also includes a threaded shaft or stud portion  47  which receives a rotary nozzle head member  50  having a series of circumferentially spaced nozzle openings or orifices  52 , as shown in  FIGS. 1–3 . The nozzle openings  52  connect with passages  54  which extends within the nozzle head  50  to a flat bottom surface  56  on the nozzle head  50 . 
   An annular valve body  60  ( FIGS. 2–5 ) seats on the upper end of the inner tubular housing  26  and is confined within the upper end portion of the outer housing  12 . The valve body  60  surrounds the valve member  35  and defines an annular chamber  62  which is closed by an annular bottom plate  64 . Diametrically opposed ports  66  are formed within the valve body  60  and are positioned to align or connect with the ports  44  formed within the rotary valve member  28  and extending from a central chamber  68  within the valve member  28 . The passage or chamber  68  is connected by the ports  42  to an annular chamber  72  surrounding the valve member  28 . 
   The upper end portion of the inner tubular housing  26  has circumferentially spaced holes or ports  74  which connect the passages  34  to the chamber  72  so that water flowing upwardly from the turbine wheel  18  through the passages  34  flows inwardly through the ports  74  and into the chamber  72  and then through the ports  42  into the chamber  68  within the rotary valve member  28 . The valve body  60  has a top wall with circumferentially spaced openings  76  connected to the chamber  62 . An annular retaining cap  78  is threaded onto the upper end portion of the outer tubular housing  12  and retains the valve body  60  against the upper end of the inner tubular housing  26 . 
   As shown in  FIGS. 2 &amp; 3 , a circular metal pattern plate  82  surrounds the threaded stud  47  and seats on the retaining cap  78 . The retaining plate defines an aperture or opening  84  which determines the arcuate spray pattern of water discharged in streams from the nozzle openings  52 . As shown in  FIG. 2 , the opening  84  is semi-circular to produce a 180° spray pattern or half circle irrigation mode. The pattern plate  82  is interchangeable with other pattern plates having different openings  84  after the nozzle head  50  is unthreaded from the stud  47  in order to obtain a different arcuate spray pattern. The plate  82  also forms a rotary seat and seal with the bottom surface of the sprinkler head  50 . 
   In operation, the water flowing upwardly through the passages  34  and into the center chamber  68  flows radially outwardly through the ports  44  and  66  when the ports  44  are connected with the port  66 . As the valve member  28  rotates with the nozzle head  50 , the port  66  are slowly closed and slowly opened by rotation of the ports  44  within the valve body  60 . Thus the water flowing into the annular chamber  62  within the valve body  60  and upwardly through the ports  76  and into the passages  54  within the nozzle head  50  cycles between a lower flow and a higher flow rate. As a result, the streams discharge from the nozzle openings  52  move between a maximum radially distance and a minimum radial distance, thereby obtaining more uniform radial distribution of the water as the nozzle head  50  rotates. The more uniform radial distribution of the water from the sprinkle unit  10  also results in a savings of water when it is desired to distribute a predetermined volume of water uniformly over a particular ground area. For example, while a commercially available irrigation unit may produce 2.5 gallons per minute (gpm) of non-uniform water distribution, cycling of water flow through ports  44  and  66  of the sprinkler unit  10  may produce about 2.2 gpm of uniform water distribution. Thus the irrigation unit  10  provides approximately 15% savings of water as a result of the more uniform radial distribution of the water from the irrigation unit. 
   While the form of sprinkler unit herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form, and that changes may be made therein without departing from the scope and spirit of the invention as defined in the appended claims. For example, the speed reducing drive  25  may be another form of reducing drive which is not a self-contained unit, or the rotary nozzle head  50  may have a drive separate from the drive for the rotary valve member.