Patent Publication Number: US-11020756-B2

Title: Orbital sprinkler with speed control brake

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 15/161,920, filed May 23, 2016, pending, the entire contents of which are hereby incorporated by reference in this application. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     (NOT APPLICABLE) 
     BACKGROUND 
     The 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; 6,530,532 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; 7,395,977; 7,562,833; 7,942,345; 8,028,932 and 8,991,724 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 important 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. 
     The embodiments shown in the noted U.S. Pat. No. 8,991,724 utilize a framework that surrounds the moving plate/cage. The framework is bulky and expensive. Additionally, such framework requires a larger diameter canister if the sprinkler head is to be mounted in a pop-up canister. Moreover, the fixed strut portions of the framework create dry shadows in the water pattern. Still further, stringy material such as moss or food processing waste in the water can hairpin and build up on the struts and cause stalling issues. 
     In the sprinkler head of the noted parent application, a wobbler ring is provided with ridges that are engageable with a gear plate as the wobbler cage is rotated. The gear plate and ridges serve to maintain control and alignment of the wobbler cage during use. As the unit orbits, the meshing of these teeth prevent rotary slippage of the wobbler cage. With each orbit, the cage advances one tooth, thereby clocking the spokes of water coming off the deflector plate to fill in the water pattern. A minor drawback with this design is that as the ridges roll across the teeth of the gear plate, the wobbler cage is shifted up and down as it rolls between the flats of the ridges. This can create unwanted drool and inconsistency in the water pattern. 
     It would be desirable to overcome the drawbacks with existing designs. 
     BRIEF SUMMARY 
     The wobbling sprinkler head according to the described embodiments provides for the desired orbital action and braking without large fixed strut framework. Eliminating the framework enables the use of a smaller diameter canister if mounting in a pop-up canister is desired. Additionally, eliminating the framework avoids the dry shadows as well as the potential for stringy material in the water to hairpin and build up on the struts. 
     The described sprinkler head also lends itself to many different shapes of water patterns without extra cost or complexity. The sprinkler head can provide for full circle watering or, by removing teeth in selected locations of a fixed gear, the wobbler cage can orbit very quickly to some areas (in areas of unbraked orbital movement) leaving very little water in these areas. Still further, the action of the water deflector plate moving in and out of the nozzle stream creates emerging/receding streams that fill in the water pattern for good distribution uniformity without an external diffuser. 
     In some embodiments, the engagement between the ridges on the wobbler ring and the teeth of the gear plate is replaced with a smooth ledge to eliminate the up and down movement of the wobbler cage as the gear teeth roll across the wobbler ring ridges. The teeth in this embodiment resist torque and thereby prevent slipping without interfering with the orbital motion of the wobbler cage. 
     In an exemplary embodiment, a sprinkler head includes a sprinkler body with a spool section having facing spool flanges on opposite sides of a spool core, where at least one of the spool flanges includes a circumferential rolling ledge. A nozzle is positioned within the sprinkler body, and a wobbler cage including a wobbler ring is supported on the spool section. A water deflector plate coupled with the wobbler cage is disposed downstream of the nozzle. A brake assembly is coupled with the water deflector plate for slowing a rotating and wobbling motion of the wobbler cage and the water deflector plate. The brake assembly includes a shaft extending through the water deflector plate and a yoke arm disposed at an end of the shaft, where the yoke arm is engageable with the sprinkler body. An underside of the wobbler ring includes a circumferential rolling surface engaging the circumferential rolling ledge of the at least one spool flange. 
     The sprinkler head may also include spool teeth positioned on an outside circumference of the one of the spool flanges with the circumferential rolling ledge. The underside of the wobbler ring may include wobbler teeth positioned radially outward of the circumferential rolling surface. In the context, the wobbler teeth may be positionable in spaces defined between the spool teeth. The spool teeth may extend radially from the outside circumference of the one of the spool flanges including the circumferential rolling ledge. In some embodiments, the spool teeth may extend axially from the one of the spool flanges including the circumferential rolling ledge. In this context, the spool teeth may include a beveled edge. Additionally, leading edges of the spool teeth may be closer to vertical than trailing edges of the spool teeth. In one embodiment, the wobbler ring may be provided with an upwardly protruding lip around its perimeter. 
     In another exemplary embodiment, a sprinkler head includes a sprinkler body having a spool section with a top spool flange facing a bottom spool flange on opposite sides of a spool core. The bottom spool flange includes a circumferential rolling ledge. A wobbler cage includes a wobbler ring supported on the spool section, and a water deflector plate is coupled with the wobbler cage. A brake assembly is cooperable with the wobbler cage for slowing a rotating and wobbling motion of the wobbler cage and the water deflector plate. An underside of the wobbler ring includes a circumferential rolling surface engaging the circumferential rolling ledge of the bottom spool flange. 
     In yet another exemplary embodiment, a spool and wobbler assembly for a sprinkler includes a spool section with facing spool flanges on opposite sides of a spool core, at least one of the spool flanges including a circumferential rolling ledge; a wobbler cage including a wobbler ring supported on the spool section; and a water deflector plate coupled with the wobbler cage. An underside of the wobbler ring includes a circumferential rolling surface engaging the circumferential rolling ledge of the at least one spool flange. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other aspects and advantages will be described in detail with reference to the accompanying drawings, in which: 
         FIG. 1  shows a wobbler-type sprinkler head according to an exemplary embodiment; 
         FIG. 2  is a cross-sectional view through the sprinkler head shown in  FIG. 1 ; 
         FIG. 3  is a close-up sectional view of the water deflector plate and brake assembly; 
         FIG. 4  is a perspective view of the sprinkler head shown in  FIG. 1 ; 
         FIG. 5  shows a wobbler-type sprinkler head according to another exemplary embodiment; 
         FIG. 6  is a cross-sectional view of the sprinkler head shown in  FIG. 5 ; 
         FIG. 7  is a perspective view of the sprinkler head shown in  FIG. 5 ; 
         FIG. 8  shows a wobbler-type sprinkler head according to another exemplary embodiment; 
         FIG. 9  is a cross-sectional view of the sprinkler head shown in  FIG. 8 ; 
         FIG. 10  is a cross-sectional view of the sprinkler head shown in  FIG. 8  with the water deflector plate in an inactive position; 
         FIG. 11  is a perspective view of the sprinkler head shown in  FIG. 10 ; 
         FIGS. 12-29  show exemplary gear configurations to effect different water patterns; 
         FIG. 30  shows a wobbler-type sprinkler in a pop-up canister; 
         FIG. 31  is a cross-sectional view of the sprinkler head shown in  FIG. 30 ; 
         FIG. 32  is a close-up cross-sectional view of the sprinkler head shown in  FIG. 31 ; 
         FIG. 33  is a cross-sectional view of the sprinkler head shown in  FIG. 31  with the wobbler cage being displaced toward an active position; 
         FIGS. 34 and 35  show the sprinkler head of  FIG. 31  in an active position; 
         FIG. 36  is a perspective view of the sprinkler head shown in  FIG. 31  with the wobbler cage in an active position; 
         FIG. 37  is a perspective view of the sprinkler head shown in  FIG. 31  in a retracted position; 
         FIG. 38  shows a wobbler-type sprinkler head according to another exemplary embodiment; 
         FIG. 39  is a cross-sectional view of the sprinkler head shown in  FIG. 38 ; 
         FIG. 40  is a close-up sectional view showing the brake gear engaged with the ring gear; 
         FIGS. 41-43  are perspective views of the sprinkler head shown in  FIG. 38 ; 
         FIG. 44  is a cross-sectional view of the sprinkler head shown in  FIG. 38  with the wobbler cage in an inactive position; 
         FIG. 45  is a perspective view of a wobbler-type sprinkler head according to another exemplary embodiment; 
         FIG. 46  is a cross-sectional view of the sprinkler head shown in  FIG. 45 ; 
         FIG. 47  is a cross-sectional view of the sprinkler head shown in  FIG. 45  in an inactive position; 
         FIG. 48  shows the sprinkler head of  FIG. 45  in the inactive position; 
         FIGS. 49-53  show a modification of the wobbler-type sprinkler head incorporating a smooth rolling surface for the wobbler ring; 
         FIGS. 54-58  show a variation of the assembly with the smooth rolling surface; and 
         FIG. 59  shows a further variation with an upwardly protruding lip around the periphery of the wobbler cage. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-4  show a wobbler-type sprinkler head  10  according to an exemplary embodiment. The sprinkler head  10  includes a sprinkler body  12  and a nozzle  14  positioned within the sprinkler body  12 . In some embodiments, the nozzle  14  is a nozzle insert that is positionable in a sideways-oriented, complementary recess provided in the sprinkler body  12 . The nozzle/nozzle insert  14  may be formed as a substantially-cylindrical body, possibly injection-molded of hard plastic material such as PVC (or other suitable plastic or metal material). The nozzle  14  may be provided with a nozzle bore with an inlet in communication with water flow and an outlet or nozzle outlet orifice that nozzles or meters water output from the sprinkler body  12 . 
     A fixed gear  16  is coupled with the sprinkler body  12 , and a wobbler cage  18  is supported on the sprinkler body  12 . A water deflector plate  20  is coupled with the wobbler cage  18  and disposed downstream of the nozzle  14 . The water deflector plate  20  is positioned to intercept, i.e., deflect, the water flow output from the nozzle  14 . The water deflector plate  20  includes a plurality of deflecting grooves  21  that deflect the water according to a predefined water pattern and also serve to impart a rotating moment on the deflector plate  20 . 
     The wobbler cage  18  supports the water deflector plate  20  as shown. The wobbler cage  18  includes a wobbler ring  22  and a plurality of struts  24  connected to the wobbler ring  22 . The water deflector plate  20  is connected to the wobbler cage  18  by the struts  24 . The deflection grooves  21  of the water deflector plate  20  may be arranged relative to the struts  24  to minimize interference by the struts  24  during use. Regardless, since the wobbler cage  18  is turning during use, any interference by the struts  24  with the projected water flow is minimal and would not result in the shadow areas that are a problem with the existing strut framework of prior designs. 
     In the embodiment shown in  FIGS. 1-4 , the wobbler cage  18  is supported on the sprinkler body  12  by a gear plate  26  secured to the sprinkler body  12  and a shoulder  28  of the fixed gear  16 . The wobbler cage  18  is positionable in the offset orientation shown in  FIGS. 1-4  by virtue of the space between the gear plate  26  and the shoulder  28  and the size of an opening in the wobbler ring  22  over the sprinkler body  12 . In some embodiments, with reference to  FIG. 2 , the gear plate  26  is integral with a sleeve member  30  secured below the nozzle housing. In some embodiments, with reference to  FIG. 2 , the fixed gear  16  is press and snap fitted into the sleeve member  30 . 
     A brake assembly  32  is coupled with the water deflector plate  20  for slowing a rotating and wobbling motion of the wobbler cage  18  and the water deflector plate  20 . The brake assembly  32  may include a shaft  34  that extends through the water deflector plate  20  and a brake gear  36  disposed at an end of the shaft. The brake gear  36  is engageable with the fixed gear  16 . In some embodiments, the brake assembly  32  is a viscous brake assembly including a rotor  38  that is press fit to the shaft  34  and is rotatable with the shaft  34 . A bearing  42  supports the opposite end of the shaft  34 . A high-viscosity damping fluid fills the cavity  40  and acts between the rotor  38  and the deflector plate  20 . Braking action is imparted when the fluid is sheared as the rotor  38  rotates relative to the deflector plate  20 . 
     In the embodiment shown in  FIGS. 1-4 , the fixed gear  16  includes external gear teeth  44 , and corresponding teeth of the brake gear  36  are engaged with the external gear teeth  44  of the fixed gear  16 . As discussed in more detail below, the external gear teeth  44  may be arranged according to a desired water pattern. In the exemplary embodiment shown in  FIGS. 1-4 , the brake gear  36  remains in engagement with the external gear teeth  44  of the fixed gear  16  regardless of whether water is flowing through the nozzle  14 . As a consequence, the brake gear  36  is always positioned out of a water stream flowing through the nozzle  14 . 
     In use, water flowing through the nozzle  14  impacts the grooves  21  on the water deflector plate  20 , which disperses the water according to a predefined water pattern. The water flow impacting the grooves  21  on the water deflector plate  20  causes the water deflector plate and the wobbler cage  18  to rotate. The brake gear  36  engaged with the teeth  44  of the fixed gear  16  serves to control a rotating speed of the water deflector plate  20 . In some embodiments, an exemplary normal speed of rotation may be in the range of 0.5-5 RPM. By removing gear teeth  44  in selected locations of the fixed gear  16 , the deflector plate  20  can orbit very quickly through some areas. In areas of unbraked orbital movement, the deflector plate  20  may quickly accelerate to a speed of several hundred RPMs or more, leaving very little water in these areas. Exemplary gear teeth configurations for the fixed gear  16  and the resulting water pattern wetted areas are shown in  FIGS. 12-23 . 
     In the embodiment shown in  FIGS. 1-4 , since the brake gear  36  maintains its engagement with the fixed gear  16 , the wobbler cage  18  and water deflector plate  20  are always tipped, eliminating the need for any other mechanism to get the deflector plate off-center at startup. 
     In some applications, the water deflector plate  20  may be subjected to side impact loads, e.g., being dragged through crops or the like. In order to prevent damage to the gear teeth  44  of the fixed gear  16  and/or the brake gear  36 , the fixed gear  16  is provided with a snout  46  that extends below the gear  16 , and the water deflector plate  20  is provided with a shoulder  48  that together take the load if the plate  20  gets struck from the side. See, e.g.,  FIG. 3 . As such, the brake gear  36  and the shaft  34  can be protected from overload. Additionally, with particular reference to  FIG. 4 , the wobbler ring  22  may be provided with ridges  50  that are engageable with the gear plate  26  as the wobbler cage  18  is rotated. The gear plate  26  and ridges  50  maintain control and alignment of the wobbler cage  18  during use. In an exemplary construction, the gear plate  26  may have fifteen teeth, and there may be sixteen ridges  50  on the wobbler ring  22 . As the unit orbits, the meshing of these teeth prevent rotary slippage of the wobbler cage  18 ; and also with each orbit, the cage advances one tooth, thereby clocking the spokes of water coming off the grooves  21  to fill in the water pattern. 
       FIGS. 5-7  show an alternative embodiment of the wobbler-type sprinkler head according to the invention. In this and subsequent embodiments, similar elements are identified with like reference numerals preceded by a third digit. 
     The sprinkler head  110  in  FIGS. 5-7  including a sprinkler body  112  utilizes a ring gear  116  with internal gear teeth as the fixed gear rather than the fixed gear  16  with external teeth shown in  FIGS. 1-4 . With the ring gear  116  and internal gear teeth, the wobbler cage  118  is positionable into an inactive position when no water is flowing through the nozzle  114  in which the wobbler cage  118  is generally level and the brake gear  136  is coaxial with an outlet of the nozzle  114  or the ring gear  116 . In an active position as shown in  FIGS. 5-7 , the wobbler cage  118  is pivoted such that the brake gear  136  is engaged with the internal gear teeth of the fixed/ring gear  116 . 
     In this embodiment, the gear plate  126  may be without spokes, and corresponding ridges  150  are provided on a deflector plate side of the wobbler ring  122  and an upstream surface of the ring gear  116 . See  FIGS. 5 and 7 . 
     As shown in  FIG. 7 , a distal end  152  of the brake gear  136  may be angled relative to a flow of water through the nozzle  114 . In some embodiments, at startup, in the inactive position, the wobbler cage will be hanging straight down. As water flows through the nozzle  114  and impacts the angled distal end  152  of the brake gear  136 , the angle of the distal end  152  will force the deflector plate  120  and wobbler cage  118  off center. Once the wobbler cage  118  and deflector plate  120  are displaced, water flow through the nozzle  114  will maintain the offset orientation of the wobbler cage  118 . 
     Gear teeth from the ring gear  116  may similarly be removed so that the deflector plate  120  can orbit very quickly through some areas to control the water pattern. Exemplary gear teeth configurations for the gear  116  and the resulting water pattern wetted areas are shown in  FIGS. 24-29 . 
       FIGS. 8-11  show another alternative construction for the wobbler-type sprinkler head  210  according to the invention. In this embodiment, the brake gear is replaced with a yoke arm  236  that is sized and positioned to loosely straddle a fixed sleeve  216 . The wobbler cage  218  and water deflector plate  220  are pivotable between an inactive position (shown in  FIGS. 10 and 11 ) and an active position (shown in  FIGS. 8 and 9 ). The wobbler ring  222  of the wobbler cage  218  is positioned between the gear plate  226  and the shoulder  228  of the fixed sleeve  216 . 
     In use, a water stream from the nozzle  214  impacts an angled surface  252  of the yoke arm  236  to force the wobbler cage  218  to an offset position toward the active position. Subsequently, the water flow impacting the water deflector plate  220  maintains the wobbler cage  218  and the deflector plate  220  in the active position. The yoke arm  236  is fixed to the shaft  234  of the brake assembly  232 . 
     In the active position, with reference to  FIGS. 8 and 9 , the yoke arm  236  engages the fixed sleeve  216  such that the orbital motion of the wobbler cage  218  causes the yoke arm  236  to rotate around the fixed sleeve  216  and also to rotate brake shaft  234 , thereby braking the orbital motion of the wobbler cage  218 . At rest, as shown in  FIGS. 10 and 11 , the brake shaft  234  is aligned with the nozzle  214  and the center of the sprinkler body  212 . 
       FIGS. 30-37  illustrate another exemplary alternative embodiment of the wobbler-type sprinkler head  310  according to the present invention. In this embodiment, the nozzle, fixed gear and wobbler cage are selectively disposable in a canister  354 . The wobbler cage  318  is displaceable in the canister  354  between a retracted position ( FIGS. 30-32 and 37 ) and an extended position ( FIGS. 33-36 ). Like conventional pop-up sprinkler assemblies, the sprinkler head is typically mounted on a riser or the like. The sprinkler components are biased to the retracted position by a spring  356  secured in the housing  312 . The assembly  332  is displaced to its extended position by pressure exerted by the water flow through the nozzle  314 . These components and their operation are generally known, and the details thereof will not be further described. 
     In the retracted position, the brake gear  336  is aligned with the nozzle  314  and is coaxial with the fixed gear  316 . Once the nozzle  314 , wobbler cage  318  and water deflector plate  320  are displaced to the extended position by water flow through the nozzle  314 , the wobbler cage  318  is pivotable into a use position as shown in  FIGS. 34-36 . In the use position, the brake gear  336  is engaged with the fixed gear  316 . The shape and orientation of the grooves  321  in the water deflector plate  320  cause the wobbler cage  318  and the water deflector plate  320  to rotate. As shown in  FIG. 35 , the brake gear  336  is provided at its distal end  352  with an angled surface so that in the resting position, at startup, the water flow impacts the angled surface of the distal end  352  to force the wobbler cage  318  off center. Like prior embodiments, the wobbler ring  322  of the wobbler cage  318  is positioned between a ledge or shoulder  328  of the fixed gear  316  and a gear plate  326 . When the water flow is terminated, the spring  356  draws the nozzle  314 , the wobbler cage  318  and the water deflector plate  320  back into the canister  354 , and the wobbler cage  318  is pivoted back to its rest position shown in  FIGS. 31, 32 and 37 . Since the wobbler cage  318  is pivotable to the orientation shown in  FIGS. 31, 32 and 37 , the unit can fit into a relatively small diameter canister. Moreover, during startup, if the water pressure is coming up slowly, while the pressure is still low and the wobbler cage  318  has not tilted over yet, the wobbler cage  318  and deflector plate  320  are free to spin and water will be flowing over the brake gear  336  and into the grooves  321  in the deflector plate  320 . This action creates small moving streams that are easy on the soil as compared to many sprinklers that have a very large concentrated, slow-moving stream at startup, which can be erosive to the soil and disturb germinating seeds. At some point, the pressure will get high enough at the angled face of the distal end  352  to create a sufficient force to tilt the wobbler cage  318 , and the unit will then operate normally. 
       FIGS. 38-44  show another alternative embodiment of the wobbler-type sprinkler head according to the invention. The sprinkler head  410  including a sprinkler body  412  is not shown in a pop-up application; but as would be readily apparent to those of ordinary skill in the art, the assembly could be put into a canister for such an application. 
     In this embodiment, teeth  437  of the brake gear  436  are engageable with corresponding fixed gear teeth  444  of the fixed gear  416 . As shown in  FIGS. 39-42 , the brake gear teeth  437  extend radially into a water stream flowing through the nozzle  414  when the brake gear  436  is engaged with the fixed gear  416  (i.e., in an active/use position as shown in  FIGS. 38-43 ). The teeth  437  of the brake gear  436  intermittently interrupt the stream between the nozzle  414  and the grooves  421  of the deflector plate  420  to further provide intermittent diffusion of the stream to fill in the distribution pattern. In this context, in all embodiments, significant intermittent diffusion of the stream occurs as the plate grooves of the water deflector plate move in and out of the stream during normal rotation of the deflector plate. This embodiment provides additional intermittent diffusion by the radially extended teeth  437  of the brake gear  436 . 
     The brake gear  436  also may be provided with an internal water passage  452 . See  FIG. 39 . The internal water passage  452  includes a bend as shown, which may be a 90-degree turn. In the startup mode, the stream is captured in the passage  452  and then turned by the bend (e.g., 90 degrees) to create an overturning moment to kick the wobbler cage  418  off center into the use position. 
       FIGS. 45-48  show another alternative embodiment of the wobbler-type sprinkler head  510  including a sprinkler body  512  according to the invention. In this embodiment, the wobbler cage  518  and the water deflector plate  520  are displaceable between the inactive position in which the brake gear  536  is not engaged with the fixed gear  516  ( FIGS. 47 and 48 ) and an active position in which the brake gear  536  is engaged with the fixed gear  516  ( FIGS. 45 and 46 ). In the inactive position, the brake gear  536  rests on the nozzle  514  to cover the nozzle. The capped off nozzle prevents insects from crawling into the nozzle when the unit is off. This feature prevents plugging of small nozzles that are used in certain applications. In this embodiment, the brake gear  536  is provided with an angled notch  552  in a surface facing the nozzle  514  to push the wobbler cage  518  and the deflector plate  520  toward the offset use position at startup. 
       FIGS. 49-58  show variations of the wobbler-type sprinkler head  610  including a sprinkler body  612  according to the invention. As shown in  FIGS. 49 and 51 , the sprinkler body  612  includes a spool section  660  with facing spool flanges  662 ,  664  on opposite sides of a spool core  668 . A nozzle  614  is positioned within the sprinkler body  612 . A wobbler cage  618  includes a wobbler ring  622  supported on the spool section  660 . Specifically, the wobbler ring  622  is positioned between the spool flanges  662 ,  664  and surrounds the spool core  668 . A water deflector plate  620  is coupled with the wobbler cage  618  as shown and is positioned downstream of the nozzle  614 . 
     The brake assembly  632  is coupled with the water deflector plate  620  for slowing a rotating and wobbling motion of the wobbler cage  618  and the water deflector plate  620 . Like the above embodiments, the brake assembly  632  includes a shaft  634  extending through the water deflector plate  620  and a yoke arm  636  disposed at an end of the shaft  634 . The yoke arm  636  is engageable with the sprinkler body  612 . 
       FIGS. 52 and 53  are close-up views showing the wobbler ring  622  engaging the bottom spool flange  664 . At least one of the spool flanges  662 ,  664  includes a circumferential rolling ledge  670 . An underside of the wobbler ring  622  is provided with a circumferential rolling surface  672  that engages a circumferential rolling ledge  670  of the spool flange(s). In the embodiment shown in  FIGS. 49-53 , the circumferential rolling ledge  670  is provided on the bottom or upstream spool flange  664 . 
     In some embodiments, spool teeth  674  are positioned on an outside circumference of the upstream spool flange  664 . As shown, the underside of the wobbler ring  622  may be provided with wobbler teeth  676  positioned radially outward of the circumferential rolling surface  672 . In use, the wobbler teeth  676  are positioned in spaces defined between the spool teeth  674  without physically engaging the spool teeth  674 . In the embodiment shown in  FIGS. 49-53 , the spool teeth  674  extend radially from an outside circumference of the spool flange  664 . 
     The embodiment shown in  FIGS. 54-58  includes similar components to the embodiment shown in  FIGS. 49-53 . In this embodiment, the spool teeth  674 ′ extend axially from the spool flange  664 ′ with the circumferential rolling ledge  670 . In use, the wobbler teeth  676 ′ are positionable in spaces defined between the spool teeth  674 ′. 
     As shown, the spool teeth  674 ′ may be tapered from a bottom to a top or include a beveled edge at the top. If the wobbler ring  622 ′ slips on the spool flanges  664 ′, the front surfaces on the spool teeth  674 ′ and the wobbler teeth  676 ′ will roll against one another, preventing further slip. Additionally, leading edges of the spool teeth  674 ′ may be closer to vertical than trailing edges of the spool teeth  674 ′. Because the sprinkler is intended to orbit only in one direction, the wobbler ring  622 ′ will slip in only one direction, and thus, these surfaces of the teeth  674 ′,  676 ′ are made more vertical so as to provide additional clearance between the teeth  674 ′,  676 ′. 
       FIG. 59  shows variation of the wobbler cage  618 ′ with an upwardly protruding lip  678  around the periphery of the wobbler cage. In freezing conditions, this lip  678  tends to help prevent ice from building up around the perimeter of the wobbler ring  622  by pooling water within the lip  678 . 
     The described embodiments provide for braking of the orbital action of a wobbler cage without using large fixed strut framework. The resulting structure reduces costs and sprinkler head size while also eliminating the dry shadows in the water pattern created by the fixed strut portions of prior designs. Eliminating the struts also prevents stringy material such as moss or food processing waste in the water to hairpin and build up on the struts. Still further, water patterns can be readily selected by positioning and/or removing teeth from the fixed gear or otherwise switching out the fixed gear to one suited for the desired water pattern. The action of the plate grooves moving in and out of the nozzle stream creates emerging/receding streams that fill in the water pattern for good distribution uniformity without an external diffuser. 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.