Abstract:
An irrigation sprinkler is provided having a turret for the distribution of irrigation water that includes a self-flushing mechanism to prevent accumulation of debris in a sprinkler control member and/or the interior of the turret. The sprinkler includes a main flow path that delivers water to a nozzle for irrigation and a secondary flow path that delivers water to flush part of the member and/or interior of the turret. The secondary flow path delivers water when the sprinkler cycles on and when the sprinkler cycles off. For example, with a pop-up sprinkler, the secondary flow path would deliver fluid sometime during its movement to the elevated position and movement to the retracted position.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to irrigation sprinklers and more particularly, to a self-flushing mechanism for rotary irrigation sprinklers. 
       BACKGROUND OF THE INVENTION 
       [0002]    Pop-up irrigation sprinklers are typically buried in the ground and include a stationary housing and a riser assembly, mounted within the housing, that cycles up and down during an irrigation cycle. During an irrigation cycle, the riser assembly is propelled through an open upper end of the housing and projects above ground level, or “pops up,” to distribute water to surrounding terrain. More specifically, pressurized water is supplied to the sprinkler through a water supply line attached to an inlet of the housing. The pressurized water causes the riser assembly to travel upwards against the bias of a spring to the elevated spraying position above the sprinkler housing to distribute water to surrounding terrain through one or more spray nozzles. When the irrigation cycle is completed, the pressurized water supply is shut off and the riser is spring-retracted back into the sprinkler housing so that the housing and riser assembly are again at and below ground level. 
         [0003]    A rotary sprinkler commonly includes a rotatable turret mounted at the upper end of the riser assembly. The turret includes one or more spray nozzles for distributing water and is rotated through an adjustable arcuate water distribution pattern. 
         [0004]    Rotary sprinklers commonly include a water-driven motor to transfer energy of the incoming water into a source of power to rotate the turret. One common mechanism uses a water-driven turbine and a gear reduction system to convert the high speed rotation of the turbine into relatively low speed turret rotation. Some examples of rotary sprinklers include the sprinklers described in U.S. Pat. Nos. 4,625,914; 4,787,558; 5,383,600; 6,732,950; and 6,929,194; all assigned to the assignee of this application, Rain Bird Corporation. 
         [0005]    During normal operation, the turret rotates to distribute water outwardly over surrounding terrain in an arcuate pattern. Rotary sprinklers commonly employ an arc adjustment mechanism, accessible from the top of the turret, to adjust the arcuate range of the turret. The arc adjustment member typically is a screw or shaft with a slotted first end manually adjustable by a tool, such as a screwdriver, to set end limits of rotation for the turret. In one example, as described in U.S. Pat. No. 5,383,600, the arc adjustment member is used to change the relative arcuate distance between two trip stops that define the limits of rotation for the turret. One trip stop is fixed with respect to the turret while the second trip stop, operatively coupled to the second end of the adjustment screw, can be selectively moved arcuately relative to the turret to increase or decrease the desired arc of coverage. 
         [0006]    During the course of normal operation, sand particles, grit, and other debris tend to accumulate in, and become trapped in, the tool-engaging slot of the arc adjustment member. After a certain amount of accumulation, the slot of the arc adjustment member becomes too clogged with such debris so as to prevent engagement with an appropriate hand tool. Attempts to engage the clogged slot with the hand tool often result in disintegration of the head of the arc adjustment member. The end result is that the arc adjustment member ceases to function, and the user can no longer adjust the water distribution arc of the sprinkler. It has been estimated that 70% to 80% of arc adjustment failures are due to the arc adjustment slot becoming damaged or otherwise failing to function in this manner. 
         [0007]    Accordingly, a need exists to periodically flush the slot of the arc adjustment member to minimize the accumulation of sand particles, grit, and other debris. There is a need for a self-flushing mechanism that prevents damage to the slot and failure of the arc adjustment member. Further, there is a need to flush the slot in a manner that does not result in the unduly wasteful use of water. In addition, there is a need to flush other adjustment members and other areas of the interior of the turret that are prone to accumulation of grit and other debris. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of an irrigation sprinkler embodying features of the present invention with a riser assembly in an elevated position for distributing water therefrom; 
           [0009]      FIG. 2  is an exploded perspective view of some of the components of the irrigation sprinkler of  FIG. 1 ; 
           [0010]      FIG. 3  is a side elevational cross-sectional view of the irrigation sprinkler of  FIG. 1  with the riser assembly in a retracted position; 
           [0011]      FIG. 4  is a side elevational cross-sectional view of the irrigation sprinkler of  FIG. 1  with the riser assembly in an elevated position; 
           [0012]      FIG. 5  is a side elevational cross-sectional view of the irrigation sprinkler of  FIG. 1  with the riser assembly in an intermediate position between the retracted and elevated positions; 
           [0013]      FIG. 6  is a perspective view of an arc adjustment member of the irrigation sprinkler of  FIG. 1 ; 
           [0014]      FIG. 7  is a side elevational cross-sectional view of the arc adjustment member of  FIG. 6 ; 
           [0015]      FIG. 8  is a perspective cross-sectional view of the arc adjustment member of  FIG. 6  showing a flow passage extending therethrough; and 
           [0016]      FIG. 9  is a top perspective view of a turret of the irrigation sprinkler of  FIG. 1 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0017]    As shown in  FIGS. 1-5 , a rotary pop-up sprinkler  10  is provided having an arc adjustment member  100  that is automatically flushed every irrigation cycle to prevent failure of the arc adjustment member  100 . The sprinkler  10  generally includes a housing  12  and a riser assembly  14 . The riser assembly  14  travels cyclically between a spring-retracted position, as shown in  FIG. 3 , and an elevated spraying position, as shown in  FIGS. 1 and 4 , in response to water pressure. More specifically, when the supply water is on, i.e., pressurized for a watering cycle, the riser assembly  14  extends (“pops up”) above ground level so that water can be distributed to the terrain for irrigation. When the water is shut off at the end of a watering cycle, the riser assembly  14  retracts into the housing  12  where it is protected from damage. 
         [0018]    The housing  12  provides a protective covering for the riser assembly  14  and serves as a conduit for incoming water under pressure. The housing  12  preferably has the general shape of a cylindrical tube and is preferably made of a sturdy lightweight injection molded plastic or similar material. The housing  12  has a lower end  16  with an inlet  18  that is threaded to connect to a correspondingly threaded outlet of a water supply pipe (not shown). The sprinkler  10  may be one of a plurality of coordinated sprinklers  10  in an irrigation network. 
         [0019]    The riser assembly  14  includes a non-rotatable stem  20  with a lower end  26  and an upper end  27 . A rotatable turret  22  is mounted on the upper end  27  of the stem  20 . The turret  22  rotates to water a predetermined arcuate pattern manually adjustable from 0 degrees to 360 degrees. The sprinkler  10  includes a reversing gear drive mechanism  130  that switches the direction of rotation of the turret  22  to create the desired arcuate sweep. The arc adjustment member  100  allows one to manually adjust the arcuate sweep settings, as described further below. 
         [0020]    The stem  20  is generally an elongated hollow tube, which is preferably made of a lightweight molded plastic or similar material. The lower end  26  includes a radially projecting annular flange  24 . The flange  24  preferably includes a plurality of circumferentially spaced grooves  42  that cooperate with internal ribs  44  of the housing  12  to prevent the stem  20  from rotating relative to the housing  12 . A coil spring  30  for retracting the riser assembly  14  is disposed in the housing  12  about the outside surface  34  of the riser assembly  14 . The spring  30  has a bottom coil  28  that engages the flange  24  and an upper coil  36  seated against the inside of a housing cover  40 . 
         [0021]    The housing cover  40  serves to minimize the introduction of dirt and other debris into the housing  12 . The housing cover  40  preferably has internal threads and is mounted to an upper end  46  of the housing  12  which has corresponding threads. The housing cover  40  also preferably includes a grippable external surface that preferably includes a plurality of vertically extending ribs  48  for enhanced gripping and easy mounting of the sprinkler  10  to a water supply pipe outlet. 
         [0022]    The housing cover  40  is fitted with a seal  50 , preferably a ring-shaped wiper seal, mounted on the inside of the cover  40 . More specifically, the support ring  52  seats the wiper seal  50  against the inside of the housing cover  40 . The wiper seal  50  preferably has an annular lip  51  that slideably engages the outside of the riser assembly  14 , as it reciprocates in and out of the housing  12  to wipe the outside of the riser assembly  14 . This wiping action minimizes the amount of debris entering the housing  12  through the space between the housing  12  and the riser assembly  14  and on the surface of the riser assembly  14 . 
         [0023]    As shown in  FIGS. 3-5 , the turret  22  defines an upper recess  21  and a lower recess  23 , which are separated by a partitioning wall  25  and the upper portion  29  of the nozzle insert socket  31 . The turret  22  includes one or more flushing orifices  39  for flushing debris from predetermined areas of the interior of the turret  22  to the exterior of the turret  22 . In one form, as shown in  FIGS. 6-9 , the one or more flushing orifices  39  may be defined by a flow passage  112 . In alternative forms, the one or more flushing orifices  39  may extend through partitioning wall  25  and/or may extend through the outer wall  41  that defines the lower recess  23 . As described further below, water exits from the one or more flushing orifices  39  as the riser assembly  14  cycles between the spring-retracted position and the elevated spraying position. 
         [0024]    A turret cover  54 , preferably made of rubber or some other elastomer material, is mounted atop the turret  22  to close the top of the upper recess  21  and provide protection against damage. The turret cover  54  includes protective access ports formed by slits  56  disposed in the top of the turret  22  ( FIG. 2 ) to enable insertion of a hand tool for manual control of various features of the sprinkler  10  or to allow discharge of water from a flushing orifice  39  in the partitioning wall  25 . The turret cover  54  also reduces accumulation of particles and other debris in the top of the turret  22 . 
         [0025]    As shown in  FIG. 2 , the sprinkler  10  also preferably includes a turret cap  58  disposed beneath the turret cover  54  in the upper recess  21  and defining a number of holes  60  to seat and support the slotted free ends of screws or shafts for the manual control of various sprinkler features. For example, a radius reduction screw  62  to secure a nozzle insert  84  and to adjust the throw radius of the sprinkler  10  is seated in one of the holes  60  and extends downward through the upper portion  29  of the nozzle insert socket  31 . The arc adjustment member  100  extends through the partitioning wall  25  and an upstanding support sleeve  33  extending into the upper recess  21 . A support web  35  extends across the upper recess  21  between the support sleeve  33  and the upper portion  29  of the nozzle insert socket  31  ( FIG. 9 ). The arc adjustment member  100  seals with the support sleeve  33  using an o-ring  63 , and is preferably seated in one of the holes  60  of the turret cap  58  to support manual control of the arc through which water is distributed by the rotatable turret  22 . In addition, the holes  60  of the turret cap  58  may be configured to provide an opening for the discharge of water from a flushing orifice  39  in the partitioning wall  25 . The turret cover  54  also preferably includes one or more downwardly projecting bosses  37  that are received by the holes  60 , such as by press fitting, for coupling the turret cover  54  to the turret cap  58  ( FIG. 2 ). 
         [0026]    As shown in  FIGS. 35 , a motor assembly  64  is mounted in the stem  20  and rotates the turret  22 . Water under pressure supplied to the sprinkler housing  12  preferably provides the power for rotatably driving the turret  22 , although numerous other conventional ways of providing power to the turret  22  may be used. The motor assembly  64  preferably includes a water-driven turbine  66  and a gear reduction assembly  68 , which are operatively coupled to rotate the turret  22 . 
         [0027]    When the riser assembly  14  is in the elevated spray position, water flows into the stem  20  and causes the turret  22  to rotate. More specifically, water enters the housing  12  through the inlet  18  and passes through the housing  12  to the riser assembly  14 . The water passes through a filter  72  mounted within the lower end  26  of the stem  20 . The filter  72  prevents grit and other debris from flowing through the riser assembly  14  to enter the riser assembly  14  and possibly causing damage to sensitive sprinkler components downstream of the riser inlet. 
         [0028]    Water flows past the filter  72  and through a spacer  74  and a stator  76  to rotatably drive the turbine  66 , which rotates at a high rate of speed, such as on the order of nearly  1900  revolutions per minute (“RPM”). In turn, the turbine  66  is connected to an axle  78 , which, in turn, is coupled to a series of reduction gears of the gear reduction assembly  68 . The gear reduction assembly  68  operatively couples the turbine  66  to the turret  22  and reduces the rotation so that the turret  22  rotates at a relatively much lower rate of speed, such as on the order of 1 RPM. In general, the gear reduction assembly  68  reduces the relatively high speed rotation of the water-driven turbine  66  to a relatively low rotational speed suitable for rotational driving of the turret  22  to provide proper irrigation. 
         [0029]    After flowing past the turbine  66 , water continues to flow through flow passage  70  and into the turret  22  through the flow tube  82 . As shown in  FIGS. 2-5 , the turret  22  is supported by a flow tube  82  extending from the gear reduction assembly  68  into the turret  22 . The reduction assembly  68  drivingly engages the lower end of the main drive shaft  131  of the reversing gear drive mechanism  130 . The upper end of the drive shaft  131  is engaged to the ring gear  133 , which is fixedly attached to the turret  22  so that the turret  22  rotates with the main drive shaft  131 . The flow tube  82  is hollow and provides a conduit for water to be delivered from the flow passage  70  to the nozzle insert  84  to be discharged for irrigation. 
         [0030]    As shown in  FIGS. 6-8 , the preferred arc adjustment member  100  is generally an elongated shaft with a first end  102  defining a slot  104 , or similarly engageable surface feature, that is accessible to and may be manually adjusted through the use of a screwdriver or other hand tool. A second end  106  of the member  100  preferably includes teeth  108  that are adapted to mate with corresponding teeth  109  disposed about the external circumference of a ring-shaped second gear  110  ( FIGS. 2-5 ) for setting one or both of the arc limits of the turret  22  through the adjustment of one or more trip stops. The second gear  110  also includes teeth  111  that are disposed about its inside circumference that mate with corresponding teeth  113  of a trip member  115  for rotation of the trip member  115 . A trip stop  119  is integrally formed with, and projects downwardly from, the trip member  115 . Thus, upon rotation of the arc adjustment member  100 , the trip stop  119  is moved relative to a fixed second trip stop  134  on the ring gear  133  to set the range of arcuate sweep for the turret  22 . The arc limits also may be set in accordance with any conventional manner of coupling the arc adjustment member  100  to the trip stops for the turret  22 , such as that described in U.S. Pat. No. 5,383,600, which is incorporated in its entirety by reference. In addition, a dust cover  121  is seated on the trip member  115  for protecting the inside of the riser  14  from grit and debris. 
         [0031]    The arc adjustment member  100  defines an elongated second flow passage  112  extending centrally therethrough. During flushing operation, as discussed further below, water flows through the second flow passage  112  from the second end  106  to the first end  102  to flush debris from the slot  104  ( FIG. 9 ) and lower recess  23  of the turret  22 . 
         [0032]    With reference to  FIG. 5 , as water flows into the riser assembly  14  and the riser assembly  14  begins to rise from a retracted position to an elevated position, water flows along two flow paths. One flow path, described above, is through the lower end  26  of the stem  20 , through the flow passage  70  of the riser assembly  14 , and out through the nozzle insert  84  to distribute water to surrounding terrain. 
         [0033]    The second flow path is within the housing  12  but outside the stem  20 . Water first flows through a first gap  114  defined by grooves  42  of the flange  24  of the riser assembly  14  ( FIG. 2 ) and the inner surface  116  of the housing  12 . Water then flows into and fills the cavity  32  in which the spring  30  is located, which is defined by the outer surface  117  of the stem  20 , the inner surface  116  of the housing  12 , and the lip  51  of the wiper seal  50  (the lip  51  sealingly engages the riser assembly  14 ). Water next flows through a second gap  118  defined by the stem  20  and the turret  22  and into the lower recess  23  and fills the lower recess  23  under pressure. Water flows from the lower recess  23  through the second end  106 , the second flow passage  112 , and the first end  102  of the arc adjustment member  100  to flush and clean the slot  104  and flush debris from slot  104  and lower recess  23 . 
         [0034]    This flushing action causes a relatively high pressure pulsing action, on the order of 5-6 pounds per square inch (“psi”), which serves to clean other sensitive parts of the sprinkler  10  that are prone to clogging. For example, the flushing water is forced out through the slit  56  overlaying the slotted first end  102  of the arc adjustment member  100 , thereby cleaning the slit  56 . Also, the flushing action has been found to clean debris from the interior of the turret  22  near the second gap  118 , including cleaning debris from the gear teeth of both the arc adjustment member  100  and the corresponding mating second gear  110 , as water flows cyclically into and out of the lower recess  23  of the turret  22 . Further, flushing water is forced out of the second flow passage  112  in the turret  22  for cleaning debris from desired areas of the interior of the turret  22 . 
         [0035]    The flushing action occurs when the riser assembly  14  is traveling between a retracted position and an elevated position. The slot  104  is preferably flushed once as the riser assembly  14  starts moving upward and once as the riser assembly  14  is returning to a retracted position. Thus, the slot  104  is flushed twice during an ordinary irrigation cycle, as described below. 
         [0036]    The second flow path receives water while the second gap  118  is below the lip  51  of the wiper seal  50 . As the riser assembly  14  continues to move upward, however, the second flow path eventually leaves communication with the water supply when the second gap  118  rises above the lip  51  of the wiper seal  50 , e.g., when the bottom of the turret  22  is spaced above the top of the housing cover  40 . Thus, when a cycle begins and water initially flows into the housing  12  and riser assembly  14 , a pulse of water is transmitted through the second flow passage  112  to flush slot  104  and through the overlaying slit  56  in the turret cover  54 . 
         [0037]    The same flushing action is repeated when the riser assembly  14  returns from an elevated spray position to a retracted position. When the riser assembly  14  is in the elevated position, the second flow passage  112  is not in communication with the water supply because the second gap  118  is spaced outside the housing  12 . However, as the riser assembly  14  continues to return to its retracted position, the second gap  118  eventually passes below the lip  51  of the wiper seal  50 , thereby placing the second flow passage in communication with the water supply. Thus, as the irrigation cycle ends and the spring  30  returns the riser assembly  14  to its retracted position, a second pulse of water is transmitted through the second flow passage  112  to flush slot  104  and slit  56 . 
         [0038]    The periodic flushing of the arc adjustment member  100  and interior of the turret  22  prevents accumulation of sand particles and other debris and is effective to maintain the operation of various components of the arc adjustment mechanism. In contrast, the accumulation of sand particles and other debris in arc adjustment members can prevent a screwdriver or other hand tool from freely engaging member  100 , thereby making routine adjustments difficult, and cause deterioration of the engaging components. 
         [0039]    Experience has shown that the size of the cross-section diameter of the second flow passage  112  impacts the effectiveness of the flushing. For example, a flow passage  112  having a cross-sectional diameter of 0.062 inches at the first end  102  was effective in flushing all of the units having that cross-sectional diameter, whereas a flow passage  112  having a cross-sectional diameter of 0.040 inches at the first end  102  was effective in flushing only about 80% of the units having that diameter. The larger diameter passage  112  at the first end  102  was more effective in maintaining the slot  104  free of sand and grit and allowed a screwdriver to freely engage the slot  104 . It should be evident that the desired diameter of the flow passage  112  will depend on the size and configuration of the arc adjustment member  100 . 
         [0040]    Although one form of an arc adjustment member  100  is shown in  FIGS. 6-8 , it should be evident that numerous other forms and configurations are available. The member  100  may be used to control the operation of features of the sprinkler  10  other than adjustment of the arc traversed by the turret  22 , and more than one member  100  may be flushed during each cycle. Further, many other shapes and sizes are available that define a flow passage therethrough that permits water flow to the end of the member  100  to be flushed. Further, the member  100  is not necessarily limited to control of the arc adjustment feature of the sprinkler  10 . Instead, the member  100  being flushed may be some other sprinkler control member used to control the operation of features of the sprinkler  10  other than adjustment of the arc traversed by the turret  22 . In addition, there is no limitation that only one such member  100  be flushed, and the sprinkler  10  may include multiple control members that are flushed during each cycle of the sprinkler  10 . 
         [0041]    In addition, other forms of the sprinkler  10  may include an adjustment member  100  with a flow passage  112  therethrough and/or one or more other flushing orifices  39 . More specifically, as described above, the sprinkler  10  may include adjustment member  100 , which defines a flushing orifice through the turret  22 , and need not include other flushing orifices  39 . Alternatively, other embodiments may include one or more flushing orifices  39  to flush debris from the interior of the turret  22  and need not include an adjustment member  100  with a flow passage  112  therethrough. Moreover, other forms of the sprinkler  10  may not flush a member  100  at all but may instead flush a predetermined portion of the interior of the turret  22 . More specifically, other forms of the sprinkler  10  may flush water out through a flushing orifice  39  in the outer wall  41  that defines the lower recess  23  of the turret  22  and/or through the partitioning wall  25  for cleaning debris from desired areas of the interior of the turret  22 . In such forms, water exits the flushing orifice  39  as the riser assembly  14  cycles between the spring-retracted position and the elevated spraying position. 
         [0042]    The foregoing relates to preferred exemplary embodiments of the invention. It is understood that other embodiments and variants are possible which lie within the spirit and scope of the invention as set forth in the following claims.