Abstract:
A water distribution plate and diffuser plate assembly for distributing a stream emitted from a sprinkler nozzle includes: a nonrotatable shaft having one end attached to a sprinkler component and an opposite end supporting first and second plates in axially spaced relationship for rotation about the shaft independent of one another. The first plate is axially adjacent the nozzle and formed with plural water distribution grooves shaped and arranged to divide a single primary stream emitted from the nozzle into a plurality of secondary streams. The second plate is downstream of the first plate and formed with plural diffuser elements arranged to be struck by at least some of the secondary streams exiting the first plate. The speed of rotation of one or both plates is slowed by viscous damping.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates to rotary sprinklers and, more specifically, to a rotary sprinkler having a stream diffuser driven in random fashion by a stream emitted from a fixed nozzle and redirected by a grooved water distribution plate in the form of plural secondary streams, some of which strike the diffuser. 
   Stream interrupters or diffusers per se are utilized for a variety of reasons and representative examples may be found in U.S. Pat. Nos. 5,192,024; 4,836,450; 4,836,449; 4,375,513; and 3,727,842. 
   One reason for providing stream interrupters or diffusers is to enhance the uniformity of the sprinkling pattern. When irrigating large areas, the sprinklers are spaced as far apart as possible in order to minimize system costs. To achieve an even distribution of water at wide sprinkler spacings requires sprinklers that simultaneously throw the water a long distance and produce a pattern that “stacks up” evenly when overlapped with adjacent sprinkler patterns. These requirements are achieved to some degree with a single concentrated stream of water shooting at a relatively high trajectory angle (approximately 24° from horizontal), but streams of this type produce a nonuniform “donut pattern”. Interrupting a single concentrated stream, by fanning some of it vertically downwardly, produces a more even pattern but also reduces the radius of throw. 
   Proposed solutions to the above problem may be found in commonly owned U.S. Pat. Nos. 5,372,307 and 5,671,886. The solutions disclosed in these patents involve intermittently interrupting the stream so that at times, the stream is undisturbed for maximum radius of throw, while at other times, it is fanned to even out the pattern. In both of the above-identified commonly owned patents, the rotational speed of the water distribution plate is slowed by a viscous fluid brake to achieve both maximum throw and maximum stream integrity. 
   There remains a need, however, for an even more efficient stream interrupter or diffuser configuration to achieve more uniform wetted pattern areas. 
   BRIEF DESCRIPTION OF THE INVENTION 
   In the exemplary embodiments of this invention, a water distribution plate and an axially spaced stream diffuser plate are mounted for rotation on a solid shaft and a hollow sleeve, respectively, surrounding the shaft. Rotation of the water distribution plate causes rotation of the diffuser plate by reason of a viscous fluid coupling between the shaft and the sleeve. Viscous damping also slows the respective rates of rotation of the two plates. 
   In one exemplary embodiment, the shaft is fixed and extends upwardly through the nozzle of a sprinkler head or body. The shaft supports the water distribution plate and diffuser plate downstream of an arcuate or full circle stream emitted from the nozzle. The water distribution plate has a generally truncated cone shape, and is formed with a plurality of grooves that are slightly curved in a circumferential direction so that when the stream emitted from the nozzle impinges on the grooves, the water distribution plate is caused to rotate about the shaft. A first stator component is fixed to the shaft and located within a sealed first chamber in the water distribution plate. The chamber is at least partially filled with a viscous fluid that causes the rate of rotation of the water distribution plate to be significantly slowed in comparison to an unbraked rate of rotation. Downstream of the water distribution plate, the diffuser plate is mounted on a sleeve surrounding a portion of the shaft. A second stator component is fixed to the sleeve in a second sealed chamber in the water distribution plate that is also at least partially filled with viscous fluid. The diffuser plate is provided with a plurality of diffuser elements projecting downwardly from a peripheral edge of the lower surface of the diffuser. 
   The lower end of the sleeve terminates adjacent the first stator and the upper end of the sleeve terminates within the body of the diffuser plate, with viscous fluid in the annular space between the sleeve and the shaft. The shaft is supported by bearings on either side of both stators, and by a bearing in the diffuser body, above the sleeve. Thus, the shaft extends from the sprinkler body, through both the distributor plate and the diffuser plate, while the sleeve, which is of shorter axial length, extends only between the distributor plate and the diffuser plate. Seals and retainer rings are used to keep the bearings in place and to prevent leakage of viscous fluid along the shaft. 
   In use, the stream emitted from the nozzle impinges on the water distribution or first plate provided with the drive grooves, causing it to rotate about the shaft. The rotation of the first plate is dampened or slowed by the first viscous brake mechanism within the distributor plate and by the viscous coupling between the shaft and the sleeve. After the secondary streams leave the distributor plate, individual random ones of the secondary streams impinge on the diffuser elements on the diffuser plate. The diffuser plate does not need to be positively driven, however, because of the shearing action of the silicone fluid between the hollow shaft and the solid shaft. In other words, a rotating action of either plate will cause the other plate to rotate because of this viscous fluid coupling. Not all of the secondary streams are diffused by the diffuser plate, and the differential rotation between the two plates insures uniformity of the wetted pattern area. To enhance the rotation of the diffuser plate, surfaces on the diffuser elements may be shaped as vane surfaces to drive the plate when impinged upon by the secondary streams from the water distribution plate. 
   In a second exemplary embodiment, the water distribution plate and diffuser plate are again mounted on a single shaft, but the shaft is supported for rotation within a sprinkler cap assembly or housing that is in turn supported on the sprinkler body downstream of the nozzle. Thus, in this embodiment, the shaft does not project upwardly through the sprinkler nozzle. 
   More specifically, the water distribution plate is fixed at one end of the shaft, for rotation with the shaft when a stream emitted from the nozzle impinges on drive grooves formed in the plate. The opposite end of the shaft is seated in a blind bore formed in a remote end of a housing component downstream of the nozzle. A first rotor is fixed to the shaft at the remote end of the housing, with a first housing bearing sealing a first chamber in which the first rotor is received. The chamber is at least partially filled with a viscous fluid and rotation of the distributor plate is dampened or slowed by viscous shearing of the fluid between the rotor and the chamber wall. 
   The diffuser plate is supported by a sleeve, adjacent the water distribution plate, and telescoped over the shaft. Thus, the shaft passes through a bearing supported in the diffuser plate, and the sleeve is supported by first and second housing bearings. A second rotor is fixed to the sleeve and the first and second housing bearings form the ends of a second chamber for the second rotor. The second chamber is also at least partially filled with viscous fluid. The diffuser plate in this embodiment is formed with curved grooves with raised flats between the grooves. In use, this second embodiment operates in a manner generally similar to the first-described embodiment. 
   Accordingly, in a first aspect, the invention relates to a water distribution and diffuser assembly for a sprinkler comprising: a shaft; a distribution plate mounted on the shaft for rotation relative to the shaft; and wherein the shaft passes through and extends beyond the distribution plate; a sleeve telescoped over at least a portion of the shaft; a diffuser plate fixed to the sleeve downstream of the distribution plate; and wherein the shaft passes through the sleeve, with the shaft supporting bearings in the distribution plate and on the diffuser plate. 
   In another aspect, the invention relates to a sprinkler comprising a sprinkler body incorporating a nozzle, a fixed shaft extending downstream of the nozzle and supporting a water distribution plate for rotation relative to the shaft, the water distribution plate formed with drive grooves adapted to receive a stream from the nozzle and to create secondary streams within the drive grooves causing rotation of the water distribution plate; a sleeve received over the shaft for rotation relative to the shaft and relative to the water distribution plate, the sleeve mounting a diffuser plate for rotation with the sleeve, the diffuser plate having diffuser elements adapted to be struck by at least some of the secondary streams; and wherein viscous fluid is present in an annular space between the shaft and the sleeve. 
   In still another aspect, the invention relates to a sprinkler comprising a nozzle adapted to emit a stream to atmosphere, a water distribution plate and diffuser plate assembly located downstream of the nozzle, the assembly comprising a shaft mounted in a housing for rotation relative to the housing; a water distribution plate fixed to one end of the shaft, the water distribution plate formed with at least one drive groove adapted to receive the stream; a sleeve received over a portion of the shaft, the sleeve mounting a diffuser plate adjacent the water distribution plate, at one end of the sleeve; the shaft and the sleeve supported by plural bearings enabling the sleeve and the diffuser plate to rotate relative to the water distribution plate and the shaft; and wherein at least one of the shaft and the sleeve mount a rotor located in a chamber at least partially filled with viscous fluid. 
   The invention will now be described in detail in connection with the drawings identified below. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a partial cross section through a rotary sprinkler incorporating a water distribution plate and diffuser plate in accordance with a first exemplary embodiment of the invention; 
       FIG. 2  is a section similar to  FIG. 1  but showing only shaft, water distribution plate and first stator component; 
       FIG. 3  is a section similar to  FIG. 1  but showing only the sleeve, diffuser plate, and second stator component; 
       FIG. 4  is a front elevation of a shaft provided with a pair of stator elements as incorporated in the sprinkler shown in  FIG. 1 ; 
       FIG. 5  is a sectioned perspective view of the water distribution and diffuser plates shown in  FIG. 1  but inverted relative to the orientation in  FIG. 1 ; 
       FIG. 6  is a partial cross section through a rotary sprinkler in accordance with a second exemplary embodiment of the invention; 
       FIG. 7  is a section similar to  FIG. 6  but showing only shaft, water distribution plate and second stator component; 
       FIG. 8  is a section similar to  FIG. 6  but showing only the sleeve, diffuser plate, and second stator component; 
       FIG. 9  is a front elevation of a shaft provided with a pair of stator elements as incorporated in the sprinkler shown in  FIG. 6 ; and 
       FIG. 10  is a sectioned perspective view of the water distribution plate and diffuser plate shown in  FIG. 9 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 1-5 , a sprinkler head is partially shown at  10  and incorporates a schematically depicted nozzle  12  supporting one end of a shaft  14 . The shaft  14  (see also  FIGS. 2 and 3 ) extends out of the sprinkler head, in a downstream direction, and supports a water distribution plate and diffuser plate assembly  16  for impingement by a stream S emitted from the nozzle. A stream deflector  18  is fixed to the shaft  14  and cooperates to define the nozzle orifice  20 . The deflector guides an arcuate (or round) stream onto the water distribution plate  22  formed with a plurality of grooves  24  shaped to divide the single vertically-oriented arcuate or full  3600  stream emitted from the nozzle  12  into a plurality of secondary streams or stream components, and to redirect those stream components in a generally radial direction. Grooves  24  are also curved slightly in a circumferential direction (see  FIG. 5 ) such that the water distribution plate  22  is caused to rotate about the shaft  14  as a result of the plurality of stream components acting on the interior walls of the grooves. Such water distribution plates are well-known in the art. 
   A diffuser plate component  26  of the assembly  16  is supported on a sleeve  28  that is telescoped over the shaft  14 . As explained in further detail below, the diffuser plate  26  and sleeve  28  are able to rotate relative to the fixed shaft  14  and independently of the water distribution plate  22 . The diffuser plate  26  is provided with a plurality of diffuser elements  30 , projecting below a lower surface  32  of the plate  26 , and arranged about a peripheral edge thereof. Each diffuser element may be provided with a curved vane surface  34  (see especially  FIG. 5 ) such that when secondary streams from the distribution plate impinge on the diffusion plate, the latter is caused to rotate. As described further below, rotation of the water distribution plate  22  is substantially uniform while rotation of the diffuser plate  26  is intermittent and random. 
   The mounting and support arrangement for the water distribution plate  22  and the diffuser plate  26  of the assembly  16  is best understood by considering each separately in connection with  FIGS. 2 and 3 . 
   With particular reference to  FIG. 2 , the water distribution plate  22  is bored and counterbored to essentially hollow out the plate, with a series of annular shoulders at increasing radii in a downstream direction from a center axis defined by the shaft  14 . More specifically, a first shoulder  35  axially adjacent the nozzle  12  supports a first conventional double-lip seal  36  that engages the shaft  14 . A second shoulder  38  supports a first distributor plate bearing  40  that supports the shaft at a location proximate the nozzle  12 . The opposite end of the shaft is supported by a second distributor plate bearing  42  that is, in turn, press-fit into a counterbore  44  ( FIG. 1 ) in the plate  26  and supported on a shoulder  46  formed in the plate. A flexible double-lip seal  48  is supported on a shoulder  50  formed in the bearing  42 , and a retainer  52  holds the seal in place. 
   A fixed (or first) stator  54  is fixed to the shaft  14  at a location adjacent the bearing  40  and forms part of a first viscous brake mechanism designed to slow rotation of the distribution plate as explained further below. 
   Turning to  FIG. 3 , the diffuser plate  26  is press-fit on the sleeve  28 , the latter extending into a counterbore  56  in the diffuser plate, and terminating at a location below the bearing  42  ( FIG. 2 ). The sleeve  28  is telescoped over the shaft  14  (see also  FIGS. 1 and 4 ), and the opposite end of the sleeve  28  is seated in a diffuser plate bearing  58  supported on a shoulder  60  ( FIGS. 1 and 2 ) in the distribution plate  22 . The sleeve  28  is also supported by a second diffuser plate bearing  62  ( FIGS. 1 and 3 ) seated on a shoulder  64  in the distribution plate  22 . Bearing  62  supports a flexible double-lip seal  66  on a bearing shoulder  68 , and a retainer disc  70  is press-fit over the shaft and into the distribution plate  22  until it engages shoulder  72 . A second stator disk or stator  74  is fixed to the sleeve  28  between bearings  58  and  62 . In this regard, note that bearings  40  and  58  have respective sleeve portions  76 ,  78  that abut the stator  54 . Similarly, a second sleeve portion  80  on the opposite side of bearing  58  and a lower end of the bearing  62  engage opposite sides of the second stator  74 . Thus, the retainer  70  with the help of fixed stators  54  and  74 , hold the bearings  40 ,  58  and  62  in place within the distributor plate  22 . 
   As best seen in  FIG. 1 , the water distribution plate stator (or first stator)  54  is located in a chamber  82  with ends of the chamber closed by bearings  40  and  58 . Chamber  82  is at least partially filled with a silicone or other suitable viscous fluid. It will be understood that the speed of rotation of the distribution plate  22  will be slowed by the fluid shearing action in chamber  82  resulting from the rotation of the plate  22  relative to the fixed stator  54 . 
   Similarly, a second chamber  84  is closed at opposite ends by bearings  58  and  62 . The diffuser plate (or second) stator  74  is located in the chamber  84 , and the latter is also at least partially filled with a viscous fluid. In this way, rotation of the diffuser plate  26  which is fixed to the sleeve  28  is slowed by the viscous shearing in the chamber  84 . 
   In use, a stream of water emitted from the nozzle orifice  20  will engage the grooves  24 , and break up into plural secondary streams. The curved grooves will cause the plate  22  to rotate but the speed of rotation will be slowed by reason of viscous shearing of fluid between the shaft  14  and sleeve  28 , as explained above. 
   Only some of the plural streams leaving the grooves  24  will strike vane surfaces  34  of the diffuser elements  30 , thus causing the diffuser plate to rotate in a sporadic and random pattern (this is because the two plates rotate at different speeds). It should also be noted that the diffuser element vane surfaces may or may not be curved so as to cause rotation of the diffuser plate  26  when struck by secondary streams. In other words, viscous fluid present between the shaft  14  and the sleeve  28  establishing a fluid coupling therebetween, such that rotation of the distribution plate  22  will cause some degree of rotation of the diffuser plate  26 . Nevertheless, rotation of the plate  26  may be enhanced by curving the vane surfaces  34 . 
   A second embodiment of a combined water distribution plate/diffuser assembly  86  is shown in  FIGS. 6-10 . In this embodiment, a more sharply defined conically-shaped water distribution plate  88  formed with curved grooves  89  is fixed to one end of a shaft  90 . A diffuser plate  92  provided with diffuser elements or grooves  94  is supported on the shaft via bearing  96  adjacent the water distribution plate, and the opposite end of the shaft  90  is received in a blind recess  98  at a remote end of a fixed housing  100 , but so as to be able to rotate relative to the housing. Bearing  96  is seated on a shoulder  97  defined by a counterbore  100  in the plate  92 . Bearing  96  supports a flexible double-lip seal  102  and both the bearing and lip seal are held in place by a retainer  104 . In this instance, a nozzle (not shown) emits a single solid stream S that is located upstream of the water distribution plate  88 , and the shaft  90  forms no part of, nor does it extend through, the nozzle supported in the sprinkler body as in the previously described embodiment. It will be appreciated, of course, that the configuration as shown in  FIG. 6  (including the nozzle) may be inverted. 
   The grooves  89  (best seen in  FIG. 10 ) in the water distribution plate  88  cause the plate  88  to rotate with the shaft, but here, the grooves continue to an apex  106  on which the solid stream S impinges and breaks up into secondary streams or stream components that flow through the grooves  94 , causing rotation of the plate  92  and shaft  90 . 
   As indicated above, the opposite end of shaft  90  is received in the blind recess  98 , with a thrust bearing  108  interposed between the shaft end and the end face of the recess. The blind recess or bore  98  is counterbored to partially define a cavity  110  that receives a first substantially cylindrical rotor  112  fixed to the shaft  90 . 
   A sleeve  114  receives the diffuser plate  92  in a press-fit relationship, the sleeve telescoped over the shaft  90  and extending from the diffuser plate  92  adjacent bearing  96 , into the housing  100  where it terminates within a bearing  116  located adjacent the rotor  112 . The bearing  116  is seated on a shoulder  118  formed by a counterbore  120 . A second substantially cylindrical rotor  122  is fixed to the sleeve  114  and is located in a second chamber  124  substantially closed by the bearing  116  and a ball bearing  126  that also supports the sleeve  114  within the housing  100 . A retainer  128  for the ball bearing  126 , a seal support ring  130  and a flexible double-lip seal  132  are all mounted on the sleeve  114 , with supporting ring  130  seated on shoulder  134  and lip seal  132  seated on ring shoulder  136 . A retainer  137  holds the lip seal  132  in place. The second chamber  124  is also at least partially filled with viscous fluid so that the rotation speed of the diffuser plate  92  is slowed by the interaction of rotor  122  and the viscous fluid in the second chamber  124 . 
   Note also that viscous fluid is present in the radial space  138  between the shaft  90  and sleeve  114 . The fluid is available from the first chamber  110  that is in fluid communication with space  118  via bore  140  in the bearing  116 . 
   The assembly  86  operates in much the same manner as the first-described embodiment. Specifically, water impinging on the plate  88  will cause that plate to rotate but at a reduced speed due to the viscous dampening or braking that results from the rotation of shaft  90  and rotor  112  in the first viscous chamber  110 . The diffuser plate  92  will rotate at a different speed when struck by secondary streams from the grooves  89  by reason of the curvature of grooves  94  but also by reason of the fluid coupling established between the shaft  90  and sleeve  114  via the viscous fluid in space  138 . As in the earlier-described embodiment, grooves  94  may or may not be curved, i.e., they may or may not serve as drive grooves. It will be understood that some of the secondary streams will also impinge on, and be diffused by, raised flats  142  circumferentially between the grooves  94  since the plate  88  rotates faster than the diffuser plate  92 . 
   While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.