Patent Publication Number: US-8991724-B2

Title: Wobbling sprinkler with viscous brake

Description:
BACKGROUND 
     This invention relates to sprinkler heads and, more particularly, to sprinkler heads that nutate, or wobble, while they rotate, to thereby minimize the “donut effect” prevalent with conventional rotating sprinkler heads. 
     Various nutating or wobbling sprinkler head designs have been proposed, examples of which are described in prior U.S. Pat. Nos. 5,381,960; 5,950,927; and 6,932,279. Commonly owned U.S. Pat. Nos. 5,439,174; 5,588,595; 5,671,885; 6,267,299; 6,341,733; 6,439,477; 7,287,710; 7,562,833; 7,942,345 and 8,028,932 provide further examples of nutating or wobbling sprinkler heads. There are potential shortcomings, however, that can nullify the very nutating affect that makes such sprinklers attractive in the first instance. 
     One problem often encountered with sprinklers of this type relates to stalling at start-up or even during normal operation. Stalling occurs when the water distribution plate of the sprinkler head fails to tilt at start-up, or ceases tilting during operation, thereby simply rotating and distributing a stream particularly susceptible to the “donut effect” where the wetted pattern area is shaped like a solid ring around a dry center. When nutating or wobbling sprinklers operate as designed, the nutating action tends to fill in the pattern in a substantially uniform manner. Thus, it is critical that the water distribution plate reliably and consistently remain in a tilted orientation on start-up and while rotating to achieve the desired wobbling or nutating action. 
     The stalling problem discussed above has been solved in different ways (see, for example, U.S. Pat. Nos. 5,381,960 and 6,341,733). 
     Another problem relates to the relatively high speed of rotation of the wobbling sprinkler head. High rotational speeds create the well-known but undesirable “horse-tail” effect that shortens the radius of throw of the sprinkler. While it has been shown that slowing the rotation of the sprinkler using a brake mechanism is effective to obtain maximum throw, completely satisfying solutions to the problem of slowing the rotation speed of a wobbling sprinkler head have yet to be developed. One attempt to slow a wobbling head is described in U.S. Pat. No. 7,395,977. 
     There remains a need for a wobbler-type sprinkler that effectively and reliably achieves maximum throw radius while maintaining the pattern-uniformity benefits of the wobbler-type sprinkler. 
     BRIEF SUMMARY OF THE INVENTION 
     In the exemplary but nonlimiting embodiments described herein, a viscous brake is eccentrically coupled to a wobbler cage supporting a deflection plate, or the viscous brake is incorporated into the wobbler cage and is eccentrically coupled to a stationary component of the sprinkler head. 
     Accordingly, in one exemplary but nonlimiting embodiment, there is provided a sprinkler head comprising a sprinkler body; a nozzle fixed within the sprinkler body; a water deflector plate downstream of the nozzle, mounted for rotating and wobbling motion relative to the sprinkler body; and a viscous brake fixed within the sprinkler body and including a shaft rotatable about a longitudinal axis passing through the nozzle, the shaft coupled to the water deflector plate for slowing the rotating and wobbling motion of the wobbler cage and the water deflector plate. 
     In another nonlimiting aspect, there is provided a sprinkler head comprising a sprinkler body having an inlet and supporting a nozzle for emitting a liquid stream along a first axis, the sprinkler body also supporting a deflector plate downstream of the nozzle, the deflector plate having grooves formed therein that are impinged upon by the liquid stream and that are curved to cause the deflector plate to rotate; the deflector plate loosely mounted on the sprinkler body causing the deflector plate to wobble as it rotates; and a viscous brake operatively coupled to the deflector plate, the viscous brake comprising a shaft, a rotor attached to the shaft and located in a chamber at least partially filled with a viscous fluid, the shaft fixed for rotation about and along the first axis and coupled to the deflector plate such that rotating and wobbling motion of the deflector plate causes rotation of the shaft and rotor about the first axis, the rotating and wobbling motion resisted by the viscous brake. 
     In still another exemplary but nonlimiting embodiment, there is provided a sprinkler head comprising a nozzle fixed within a sprinkler body; a water deflector assembly downstream of the nozzle, mounted for rotating and wobbling motion relative to the sprinkler body; a wobbler cage including a viscous brake supported within the wobbler cage for slowing the rotating and wobbling motion of the wobbler cage and the water deflector plate, the viscous brake including a shaft operatively coupled to a pin centered on a stationary cap portion of the sprinkler head. 
     In still another exemplary but nonlimiting embodiment, there is provided a sprinkler head comprising a sprinkler body having a longitudinal center axis; a nozzle supported in the sprinkler body, the nozzle having an orifice on the longitudinal axis; a wobbler cage including a multi-grooved water deflector plate downstream of the nozzle and adapted to receive a stream emitted from the nozzle; the wobbler cage tilted relative to the longitudinal center axis and mounted for rotating and wobbling motion relative to the sprinkler body; and a rotary brake located within the sprinkler body or the wobbler cage for slowing the rotating and wobbling motion of the wobbler cage and the water deflector plate, the rotary brake coupled between the wobbler cage and the sprinkler body. 
     The invention will now be described in detail in connection with the drawings identified below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevation view of a wobbler-type sprinkler head in accordance with a first exemplary but nonlimiting embodiment of the invention; 
         FIG. 2  is a vertical cross section through the sprinkler head shown in  FIG. 1 ; 
         FIG. 3  is a partial-perspective view of the upper portion of the sprinkler head shown in  FIGS. 1 and 2 ; 
         FIG. 4  is a partial, vertical cross section of the upper portion of a sprinkler head in accordance with a variation of the sprinkler head embodiment illustrated in  FIGS. 1-3 ; 
         FIG. 5  is a partial-perspective view of the upper portion of the sprinkler head shown in  FIG. 4 ; 
         FIG. 6  is a side elevation of a sprinkler head in accordance with a second exemplary but nonlimiting embodiment; 
         FIG. 7  is a vertical cross section taken through the sprinkler head in  FIG. 6 ; 
         FIG. 8  is a side elevation of a third exemplary embodiment of the invention; 
         FIG. 9  is a vertical cross section taken through the sprinkler head shown in  FIG. 8 ; 
         FIG. 10  is a vertical cross section taken through the upper portion of a sprinkler head in accordance with another exemplary but nonlimiting embodiment of the invention; and 
         FIG. 11  is a sectioned, partial-perspective view of the upper portion of the sprinkler head shown in  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION 
     First Embodiment 
       FIGS. 1-3  illustrate a sprinkler head  10  in accordance with first exemplary but nonlimiting embodiment of the invention. The sprinkler head  10  includes a sprinkler body assembly  12  which may include an inlet adapter  14  (attached by, for example, a threaded connection) that allows the sprinkler head to be attached to a flexible conduit, fixed riser or other irrigation component (such as a pressure regulator), utilizing the externally-threaded end  16  of the adapter. A nozzle body  18  is supported within the sprinkler body assembly, the nozzle bore  20  ( FIG. 2 ) aligned with the inlet adapter  14  such that a stream of water (or other liquid) follows an axial path through the sprinkler body assembly. The manner in which the nozzle body  18  is secured within the sprinkler body will be described in detail further below. The sprinkler body assembly  12  also includes a plurality of upwardly-extending, outer struts or standards  22  integrally-formed at their lower ends with a lower substantially-cylindrical bushing  24  from which an internal cylindrical sleeve  26  extends upwardly, as best seen in  FIG. 2 . The struts  22  are engaged at their uppermost end with an upper substantially-cylindrical bushing  28  that supports a viscous brake assembly  30 , also described further below. 
     A spool  32  is received over the sleeve  26  and includes a center hub  34  and upper and lower radially-extending flanges  36 ,  38 , respectively. The lower bushing  24  is formed with a radial shoulder  40  on which the spool  32  rests. An upper retention ring  42  is telescopically received over the sleeve  26  and holds the spool  32  in place on the sleeve  26 . It will be appreciated that the sprinkler body assembly, including the spool  32 , remains stationary during operation. 
     The nozzle body  18  is formed with a radial flange  44  that engages an upper end  46  of the adapter  14 . The internal bore  20  is tapered inwardly at  48 , and leads to a nozzle orifice  50 . The nozzle body  18  also includes an exterior identification ring  52  that permits the user to determine at a glance the orifice size of the nozzle. Thus, the nozzle body is sandwiched between the upper end  46  of the adapter and the bushing  24 . It will be appreciated that the nozzle body  18  is easily removed and replaced by the same or different-size nozzle simply by unscrewing the adapter  14  and sliding the nozzle off the adapter. In this regard, the threads on the adapter are circumferentially discontinuous, leaving axially-oriented gaps or slots which receive circumferentially-spaced spokes or webs formed in the nozzle body. The nozzle body  18  is of known construction and is described in further detail in commonly-owned U.S. Pat. No. 5,415,348. The nozzle construction is not particularly relevant to this invention, however, and need not be described in any greater detail herein. 
     A wobbler cage  58  is supported on the spool  32 . More specifically, the wobbler cage  58  includes a disc-like stream deflector or distribution plate  60  formed with a plurality of radially-extending, circumferentially-curved grooves  62 . The deflector plate is supported on a plurality of posts  64  extending upwardly from a lower ring  66 , and radially inward of the struts or standards  22 . The lower ring  66  is loosely received over the hub  34 , permitting rotating/wobbling movement of the wobbler cage  58  about the spool hub  34 , but confined between the spool flanges  36 ,  38 . 
     A bore or recess  68  is formed in the upper, center portion of the distribution plate  60  and opens in an upward direction so as to receive a pin  70  projecting downwardly from a brake disc  72 . The pin  70  is offset from a brake shaft  74  so as to be located eccentrically relative to a center aperture  76  in the brake disc  72  which receives the shaft  74 . The shaft  74  extends into the brake housing  78  and is received in a recess  80  at the remote end of the brake housing. A substantially-cylindrical rotor  82  is fixed to the shaft  74  within a chamber  84  in the brake housing  78  that is filled, or at least partly filled with a viscous fluid. The chamber  84  is sealed at its lower end by a shaft seal  86 . A shaft bearing  88  located within the housing provides additional support for the shaft  74 . 
     In operation, when a stream is emitted from the nozzle orifice  50 , it strikes the deflector plate  60  and because the grooves  62  have a component of curvature in a circumferential direction, the deflector plate  60  and wobbler cage  58  are caused to rotate, and, as a result of the loose fit between the ring  66  and the spool  32 , the wobbler cage  58  also wobbles as it rotates. As a result of this rotating/wobbling action, the wobbler cage  58  also rotates the disc  72 , shaft  74  and the rotor  82  within the chamber  84 . The rotation is resisted by the viscous fluid within the chamber  84  as the fluid is “sheared” between the rotor  82  and the chamber wall. This viscous fluid resistance or friction slows down the rotation of the shaft  74  and, through the brake disc  72 , also slows the rotating/wobbling motion of the wobbler cage  58 . Note that with the stream deflector and wobbler cage  58  are tilted or angled relative to the longitudinal axis A passing through the nozzle orifice  50  and coincident with the shaft  74 , the pin or post  70  projects at a similar angle relative to the shaft  74  so as to properly seat in the recess  68  as the wobbler cage rotates and wobbles about the axis A. Note also that the pin  70  seated in the recess or bore  68  insures that the stream deflector and wobbler cage  58  will always remain tilted relative to the longitudinal axis A, thus precluding stalling under any conditions. 
       FIGS. 4 and 5  illustrate an alternative construction where the brake disc  172  is formed with an open-ended slot  168  adapted to receive a post or pin  170  projecting upwardly from the deflector plate  160 . In other words, the operative coupling elements between the deflector plate  160  and the eccentrically-located brake disc  172  have been reversed relative to the arrangement in  FIGS. 1-3 . In this instance, the open-ended slot  168  facilitates assembly, particularly with respect to locating the pin  170  when the wobbler cage  158  is installed on a sprinkler head. Otherwise, the construction and operation remains as described above in connection with  FIGS. 1-3 . In this regard, only those reference numerals that are required to understand the difference between the embodiment of  FIGS. 4 and 5  and the embodiment of  FIGS. 1-3  have been used in  FIGS. 4 and 5 . For ease of understanding, similar numbers, but with the prefix “1” added, are used to designate the different but corresponding component parts. 
     Second Embodiment 
       FIGS. 6 and 7  illustrate another exemplary but nonlimiting embodiment where the wobbler cage orbits and wobbles about an annular race supported on the sprinkler body. More specifically,  FIGS. 6 and 7  show a sprinkler head  210  that includes a sprinkler body assembly (or simply, “sprinkler body”)  212  fitted with an adapter  214  and supporting a nozzle body  218  in substantially the same manner as described above in connection with the first embodiment. 
     A sleeve  220  is integrally formed with or attached to the sprinkler body  212 , and extends downstream (upwardly as viewed in  FIGS. 6 and 7 ) of the nozzle orifice  222 , with the lower portion of the sleeve slotted (as at  224  and  226 ) permitting air to flow into the nozzle area to enhance stream integrity as the stream exits the end of the sleeve  220 . As in the previously-described embodiment, a water-deflector plate  228  is provided with plural radially-oriented grooves  230 , some or all of which are curved in a circumferential direction to cause the plate  228  to rotate when impinged upon by a stream emitted from the nozzle body  218 . 
     The water deflector plate  228  is supported on a wobbler cage  232  for wobbling or nutating motion about the axis A passing through the nozzle body  218 , as viewed in  FIG. 7 . More specifically, the water-deflector plate  228  is supported on three circumferentially-spaced posts  234  (two shown in each of  FIGS. 6 and 7 ). The posts  234  in the exemplary embodiment are molded integrally with an upper end of an upper spool component  236  of the wobbler cage  232  extending substantially vertically upwardly from an upstanding, partially conical, peripheral wall  238  to the water deflector plate  228 . The upper ends of the posts may extend through apertures  240  in the plate  228  as best seen in  FIG. 7 , and secured by screws  242  or other fasteners such as lock-washers, or alternatively by means of, for example, heat and pressure applied to the tips of the posts, i.e., by heat staking. 
     The upper spool component  236  is threadably attached to a lower spool component  244 . This split-spool arrangement is employed primarily to facilitate manufacture, but a one-piece spool is not outside the scope of this invention. As best seen in  FIG. 7 , the upper spool component  236  is formed with an upper, substantially radially-oriented spool flange  246  and the lower spool component  244  is formed with a substantially radially-oriented upper surface  248  serving as a lower spool flange. The upper spool flange  246  and the lower spool flange  248  are connected by a substantially-cylindrical hub surface  250 . 
     An annular race  252  is secured to an upstanding-internal, annular wall  254  of the sprinkler body  212  by screws or other fasteners  256 . The race  252  may be made of a hard rubberized plastic (or other suitable material), molded about an annular metal flange  258  which facilitates attachment to the wall  254 . The upper surface  253  of the race is formed with traction teeth  260  adapted to engage similar teeth  262  formed on the upper spool flange  246  as the cage  232  wobbles about the race. The number of teeth on the respective surfaces differs by at least one, thus changing the relative location of the grooves  230  on each “orbit” of the race to facilitate an even more uniform pattern by preventing dry spokes between the streams emitting from the grooves in the deflector plate. 
     The manner in which brake disc  268 , pin  270  and viscous brake  266  (supported in the bushing  272 ) work in connection with the wobbler cage  232  (and specifically the deflector plate  228 ) is otherwise as explained above in connection with the first embodiment. 
     In this second embodiment, the sprinkler body  212  is formed into separable components, a lower portion  274  supporting the adapter  214  and nozzle body  218 ; and an upper portion  276  that includes the struts or standards  264  and the viscous brake  266 . The upper and lower portions  274 ,  276  are connected by, for example, a threaded attachment as shown at  278 . This arrangement, in combination with the tapered wall  238  of the spool  232  and the air flow through the sleeve  220 , provides effective shielding for the nozzle body  218 , preventing or at least minimizing the collection of debris in and/or around the sleeve  220  and nozzle orifice  222 . 
     Third Embodiment 
     In another exemplary embodiment shown in  FIGS. 8 and 9 , a wobbler cage  280  is incorporated into a sprinkler body cap assembly  282  that is removably attached to a sprinkler body  284 . More specifically, as best seen in  FIG. 9 , the sprinkler body  284  includes an upper ring  286  which is supported by circumferentially-spaced standards  288  extending upwardly from a hub portion  290  of the sprinkler body. 
     The cap assembly  282  includes a lower flange portion  292  that attaches to the upper ring  286  by means of a bayonet, snap-fit, threaded or other suitable connection. An outer cap wall  294  extends upwardly from the lower flange portion  292  to an upper cap portion  296 . The upper cap portion  296  is formed with a center hub  298  that supports the viscous brake  300  in a manner similar to the viscous brake mounting arrangement shown in  FIGS. 1 and 2 . In this regard, the brake housing  301  may be snap-fit or otherwise suitably secured within the center hub  298 . 
     The viscous brake shaft  302  extends beyond the viscous brake housing  301  and mounts the brake disc  304 . The brake disc  304  is formed with an angled, eccentric pin  306  that is received in the wobbler cage  280  as described further below. 
     The wobbler cage  280  includes a water deflector plate  307  provided with distribution grooves  308  similar to those described in connection with the embodiments of  FIGS. 1-7  that cause the plate  307  to rotate when impinged upon by a stream emitted from the nozzle  310 . A cylindrical stem  312  of the plate  307  is telescopically received over a bushing  314  of a lower spool component  316  of a spool assembly  318 , in a snap-fit, press-fit or other suitable attachment arrangement. The lower spool component  316  is shaped to provide peripheral shield  320  that, in combination with the outer, annular cap wall  294  and the inner annular wall  322 , substantially encloses the spool assembly  318 , preventing ingress of debris that might otherwise hamper the nutating/wobbling action of the wobbler cage  280 . An upper spool component  324  is press and/or snap-fit into the lower spool component  316  at  326 . 
     The spool assembly  318  comprises upper and lower rings  328 ,  330 , each of which has a cylindrical component which enables the rings to be telescoped over opposed bushing portions of the upper and lower spool components  324 ,  316 . The rings  328 ,  330  are separated by a sleeve or spacer  332  that serves as the spool hub. 
     The spool assembly  318  is loosely secured within an annular ring or race  334  that may be made of suitable wear-resistant material, such as a ceramic. An annular retainer  336  is secured to the race and press or snap-fit over the inner wall  322  so as to hold the race in place. The spool assembly  318  is thus received in a center cavity  338  defined by the inner annular wall  322  of the cap assembly. The inner annular wall  322  is supported by (or integrated with) the outer annular cap wall  294  by means of circumferentially-spaced ribs (one shown in  FIG. 9  at  340 ). 
     As noted above, the upper end of the upper spool component  324  receives the pin  306  projecting from the brake disc  304 . The viscous brake  300  reduces the speed of the wobbler cage  280  via the coupling at pin  306  and upper spool component  324  in the same manner as described above in connection with the earlier-described embodiments. 
     Fourth Embodiment 
     Turning to  FIG. 10 , a fourth exemplary embodiment is illustrated wherein the viscous brake assembly has been moved to a location within the wobbler cage. More specifically, the upper cap component  342  of the cap assembly  344  has been modified (as compared to  FIGS. 8 and 9 ) to include a centrally-located pin or post  346 . At the same time, the upper spool component  348  has been lengthened to provide sufficient space to house the viscous brake assembly  350 . The brake shaft  352  extends out of the brake assembly and secures the brake disc  354  which is formed with an offset round or oblong aperture  356  that receives the pin or post  346 . As in the previous embodiment, the space enclosed by the internal wall  358  and the space  360  provided within the upper cap portion  342  is sufficient to allow the wobbler cage  362  to wobble freely as it rotates about the annular race  364 . In this regard, with the exception of the extended upper spool component, the remainder of the wobbler cage  362  is substantially identical to the wobbler cage arrangement of  FIGS. 8 and 9 . It will also be appreciated that the remainder of the sprinkler body including the nozzle and adapter configuration is also substantially identical to that shown in  FIGS. 8 and 9 . 
     It should also be noted that the lower spool component  366  may be constructed of any suitably heavy metal material, e.g., brass, to also serve as a counterweight that promotes a controlled nutating action of the wobbler cage  362 . 
     This arrangement reduces the overall profile of the sprinkler and provides better protection for the viscous brake assembly  350 . 
     All the figures show a simple viscous brake such as is disclosed in commonly-owned U.S. Pat. Nos. RE 33,823 and 5,372,307. However, more complex viscous brakes such as disclosed in commonly-owned U.S. Pat. No. 7,980,488 could be used as well to impart fast/slow rotation if desired. It will be understood, however, that non-viscous types of rotary brakes of various types could be used, including mechanical friction brakes and magnetic brakes. In addition, and as made apparent from the embodiments described above, the brake may be incorporated into either the sprinkler body or the wobbler cage, but the invention does not exclude the possibility of brake components in both the sprinkler body and the wobbler cage. 
     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.