Oscillating water sprinkler
BACKGROUND AND SUMMARY OF THE INVENTION 
     A great variety of lawn sprinklers has been devised and manufactured. All are intended to distribute water as uniformly as possible over a given lawn area at the rate at which the water will soak into the ground. Some are simple sprinkler manifolds with no moving parts. Some provide for a multiplicity of streams from nozzles which rotate about a vertical or horizontal axis, and many are adjustable to limit the area to be sprinkled at any given setting. The constantly moving streams are preferable in that they spread the water for a given location of the sprinkler over a larger area for optimum absorption. While sprinklers rotating about a vertical axis supply water to a circular area, sprinklers which oscillate about a horizontal axis serving a rectangular area are generally preferred because the entire lawn can be uniformly watered by successively sprinkling areas with straight common boundries. 
     To achieve improved certainty and continuity of operation and uniform watering for a given setting, horizontal oscillating sprinklers have become increasingly complex with concomitantly increasing cost and mechanical failure probability. 
     Paddle-piston-type horizontal oscillating sprinklers have been designed to switch the routing of streams of water by fluid action alone to minimize the number of moving parts, as in U.S. Pat. Nos. 3,767,118 and 3,829,018, owned by the assignee of the present application. Some of these sprinkler designs employ a &#34;fluidic&#34; type of flow circuitry in which when one stream starts to flow, it deflects another stream to an alternate position. 
     While these designs were effective over the range of pressures at which water is usually supplied for residential service, an oscillating water sprinkler capable of satisfactory operation over a wider range of water pressures and having a switching mechanism as nearly independent of water pressure and immune to line pressure fluctuation as possible within practical limits would have obvious advantages. 
     Another object of the invention is to improve upon the &#34;squeegee&#34; or &#34;revolving door&#34; type wiper flange, disclosed in the above-identified patents, which seals the paddle-piston to the motor chamber and to generally improve the delivery of water to the sprinkler. 
     These and other objects of the invention are achieved by employing a snap-action toggle valve to reverse the direction of an oscillating sprinkler powered by a paddle-piston motor. Adjustable stops on the sprinkler tube actuate the valve at the end of each sweep, alternately opening left and right motor chamber channels interconnected to a sprinkler supply channel feeding the sprinkler tube without interruption. A special vane on the sprinkler tube where it intercepts the sprinkler supply channel prevents vortex action. The edges of the paddle-piston are sealed to the walls of the motor chamber by a separate flexible, double-flanged, slip-on wiper element. 
     The achievements and advantages of the oscillating water sprinkler of this invention will become more fully apparent as the description thereof proceeds in connection with the accompanying drawings. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the oscillating water sprinkler of the invention. 
     FIG. 2 is a front view of the sprinkler of FIG. 1. 
     FIG. 3 is a cross-sectional view taken at the line 3--3 of FIG. 2. 
     FIG. 4 is a cross-sectional view taken at line 4--4 of FIG. 3. 
     FIG. 5 is a top detail view of the paddle-piston wiper element for the sprinkler of FIGS. 1-4. 
     FIG. 6 is a cross-sectional view of the wiper element taken along the line 6--6 of FIG. 5. 
     FIG. 7 is a cross-sectional view of the wiper element taken along the line 7--7 of FIG. 6. 
     FIG. 8 is a front detail view of the circuit plate of the sprinkler of FIGS. 1-4. 
     FIG. 9 is a rear detail view of the circuit plate of FIG. 8. 
     FIG. 10 is a sectional view of the circuit plate taken along line 10--10 of FIG. 8. 
     FIG. 11 is an axially exploded perspective view of the lever, cam shaft and rocker for the sprinkler of FIGS. 1-4 shown in relation to the cam follower and paddle chamber molding with the fluid channels in phantom. 
     FIG. 12 is composed of three rear axial views of the lever, cam shaft and rocker from left to right, respectively, as indicated by the lines 12 of FIG. 11. 
     FIGS. 13-16 are diagrammatic views of the internal water channels with the motor chamber and paddle-piston in phantom showing the operation of the snap-action valve at consecutive points in one operating cycle. 
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENT 
     As seen in FIG. 1, the sprinkler comprises a base including a housing 1 having sides 2 and ends 3 mounted upon supporting legs 4. Sprinkler tube 5, which may be essentially straight, comprises interior middle sleeve 5a (FIG. 3) and nozzle manifold tubes 5b and 5c, these tubes being provided with rows of spaced nozzles 6 which may be progressively increasingly tilted outwardly to provide a uniform sprinkling fan pattern throughout the width of the rectangular lawn area sprinkled for a particular setting of the sprinkler. Each manifold tube 5b and 5c is affixed and sealed to the middle sleeve 5a by means of a threaded nozzle 6a and an O-ring as shown in FIG. 3. The ends of the sprinkler tube 5 are closed by plugs 7 and 8. 
     An inlet snout 9 equipped with a hose coupling 10 projects from the rear of the housing for connection of the water supply hose to the sprinkler. Lever 11, mounted for movement back and forth about its hub 12, projects through the front 3 of the housing for engagement of stops 13 and 14. Lever 11 is the activating lever of the sprinkler tube oscillating control valve. Stops 13 and 14 are adjustable by manual rotational manipulation of the respective handle ends 13a and 14a. The stop assembly is mounted on one end of the sprinkler middle sleeve 5a and is carried in oscillation with the sprinkler tube assembly. Adjustable stops 13 and 14 are sandwiched between washers 15, 16 and 17 (FIG. 3). Outer washer 17 has an integral cylindrical cover fastened to washer 15 with screws (not shown). The handle ends 13a and 14a of the stops project through a circumferential slot in the cover of washer 17 which limits their angular separation. Preferably, the middle washer 16 is a crown gear with radial grooves like a poker chip engaging identical facing surfaces on the coaxial ring-like portions of stops 13 and 14. 
     When the predetermined end of a sweep in one direction is reached, stop 13 or 14, as the case may be, engages the end of lever 11 and moves it so as to switch a toggle valve which routes water through alternate channels, as will be described in detail hereinafter, to effect reversal of the direction of rotation of the sprinkler tube for the return sweep with eventual engagement of the other stop with the end of lever 11, to continue the oscillation of the sprinkler tube. 
     The housing 1 of the sprinkler is composed of two moldings, one forming the top, bottom, both sides 2 and the rear which has the water inlet 9. The other molding forms the front 3 through which the switch lever hub 12 projects. The internal structure of the sprinkler, as shown in FIG. 3, is mounted entirely within the first or larger of these two housing parts and includes a motor chamber molding 18 forming the motor chamber 18a. When closed by the cover plate 19, the motor chamber forms a coaxial sector of an annular disc. The motor chamber molding 18 also provides upper coaxial opening 18b through which the paddle-piston hub and middle sprinkler sleeve 5a pass and lower opening 18c which receives the O-ringed end of the hose coupling connector 20. Adjacent to the paddle chamber molding 18, separated by a flat gasket 21, is a plate circuit molding 22 which is connected to the paddle chamber molding 18 by means of screws 23. The plate circuit 22 has channels defined therein for routing water from the inlet snout 9 and hose connector 20 into the interior of the sprinkler tube 5 via circumferential intake port 24 formed through sleeve 5a and simultaneously up into the motor chamber 18a by one of two paths. 
     The plate circuit molding 22 has a switch chamber 22a which communicates with the opening 18c in the motor chamber molding to receive supply water and an upper coaxial opening 22b l through which the middle sleeve 5a passes. U-cup seals 25 make a watertight connection for the middle sleeve 5a as it rotates in the aligned coaxial openings in the motor chamber molding 18, cover 19, gasket 21 and circuit plate molding 22. The middle sleeve has a short axially projecting vane 5d which prevents vortex action of the water exiting supply channel 34 by prohibiting the water from circulating around the outside of middle sleeve 5a. Prevention of the vortex action enhances flow from the supply channel 34 through the intake port 24. 
     As shown in FIGS. 3 and 4, a vane-like paddle-piston 26 is located within the water chamber 18a. The paddle-piston 26 includes an integrally molded hub 26a coaxial with the sprinkler tube and middle sleeve and a rectangular blade which extends radially from the hub in a plane parallel to its axis and occupies nearly the entire cross-sectional area of the motor chamber 18a. The paddle-piston hub 26a has an internal axial key 26b received in a complementary keyway on the corresponding external surface of the middle sleeve 5a which fits inside and rotates with the paddle-piston hub. 
     On the opposite side of the paddle-piston hub 26a, a small axial rib 26c projects from the exterior surface of the hub forming an obstruction in the annular channel between the hub 26a and the coaxial opening 18b in the motor chamber molding, thereby serving as a bearing surface for the paddle-piston 26. The rib 26c also prevents water in the motor chamber on one side of the paddle-piston from communicating with the other side of the paddle-piston and motor chamber through the coaxial opening 18b. 
     The paddle-piston blade is fitted with a U-shaped, frame-like, double-flanged, slip-on sealing wiper 27, preferably of injection molded polyethylene, which engages and slides along the walls of the motor chamber, as shown in detail in FIGS. 5-7. The wiper includes a base portion 27a and two parallel flanges 27b extending axially therewith. The parallel flanges grip the edge of the paddle-piston. A pair of outwardly flared flanges 27c extend from the base portion 27a, opposite the parallel flanges 27b. The outwardly flared flanges 27c provide sealing, sliding contact with the motor chamber 18a. 
     Paddle-piston blade 26 with its sealing wiper 27 divides the motor chamber 18a into two watertight compartments with a movable common partition rotatable back and forth through about ninety degrees of arc without losing its seal. 
     Ports 19a and 19b permit the flow of water under supply pressure into one compartment of the motor chamber and permit the flow of water out of the other compartment of the motor chamber (and ultimately joining the main flow to the nozzles 6) to drive the paddle-piston 26 in rotation one way or the other. A toggle valve assembly connects ports 19a and 19b alternately to the water supply and the sprinkler tube 5. 
     As shown in FIGS. 8 and 9, the switch chamber 22a, shaped like an inverted mushroom slice, has its lower oblong area (cap) in direct communication with the hose connector 20. A stepped circuit opening 22a (FIG. 9) is located in the middle of the lower oblong area of the switch chamber 22a through the back of the circuit plate molding 22. The top (stem) of the switch chamber 22a defines two parallel spring chambers 22d. 
     Left and right motor chamber filling channels 28 and 29, respectively, are defined in the circuit plate molding 22 and extend along either side of upper stem portion 22d of the swtich chamber and curve or flare slightly outwardly up to circular junction points 30 and 31, respectively, which coincide respectively with ports 19a and 19b of the motor chamber cover plate. The junction points 30 and 31 are also connected via respective curved merging discharge channels 32 and 33 to a single main sprinkler tube supply channel 34 which leads to an annular channel 35 coaxially defined around the circumference of the sprinkler tube opening 22b in the circuit plate through which the middle sleeve 5a is rotatably received. The merging channels 28 and 32 on one side form a cursive V-shape as do the complementary merging channels 29 and 33 on the other side of the circuit plate. FIG. 10 shows the &#34;windows&#34; or inlet ports 36 and 37 through which the switch chamber 22a communicates with the left and right filling channels 28 and 29. The channels, chambers and openings formed in the circuit plate molding 22 are all symmetrical with respect to the orthogonal plane through the centers of openings 22b and 22c. 
     As shown in FIG. 4, a rocker 38 serves as a toggle valve and is pivotally mounted in the switch chamber 22a so that in its extreme alternate positions it blocks one or the other of inlet ports 36 and 37, thus alternately connecting the left and right filling channels 28 and 29 to the water supply via the switch chamber 22a. A U-shaped cam follower 39 with a pointed bottom projection 39a is slidably received in the stem portion of the switch chamber 22a so that the legs of the follower fit in the spring chambers 22d. Coil compression springs 40 are inserted in the remainder of the upper ends of the chamber 22d to urge the follower downwardly. 
     Cam shaft 41 is sealingly and rotatably received through the stepped opening 22c in the circuit plate molding 22. The rocker 38 is pivotally mounted on the end of the cam shaft 41. The outer (left in FIG. 3) end of the cam shaft 41 projects through the front plate 3 to receive the keyed hub 12 of the switch lever 11 which may be secured by a screw. The inner end of the cam shaft 41 in the switch chamber carries the pointed cam surface 41a (see FIG. 11) which engages the cam follower 39. The cylindrical inner end of the cam shaft 41 is rotatably received in the central circular opening 38 (FIG. 12) of the rocker. The cam shaft can turn freely within the rocker 38 over an arc limited by the engagement of the side of the cam 41a with one side or the other of the U-shaped opening 38b in the rocker. There is enough rotational &#34;play&#34; between the cam shaft and the rocker that the cam shaft may rotate slightly past top dead center (where the follower is fully raised) in either direction without disturbing the position of the rocker. 
     In FIG. 4 the paddle-piston 26 is centered in the motor chamber 18a in the middle of a counterclockwise sweep as is indicated by the arrows showing flow into and out from the chamber. Water in the switch chamber 22a is flowing through the open inlet port 36, up the left filling channel 28 and into the left compartment of the motor chamber through port 19a . The right-hand compartment of the motor chamber 18a is being emptied through port 19b via the discharge channel 33. Water rushing through the curved discharge channel 33 into the sprinkler supply channel 34 tends to aspirate water from the merging left discharge channel 32 thus dividing the water from the left filling channel 28 into two streams: one flowing into the motor chamber and the other joining the sprinkler supply channel 34 which supplies water to the sprinkler tube 5. 
     With reference to FIGS. 4 and 13-16, the situation of the switch mechanism remains unchanged until the paddle-piston has turned counterclockwise through almost its entire arc and is reaching its right-hand extremity (FIG. 13). At this point, the stop 14 (FIG. 2), which rotates with the paddle-piston, engages the end of the switch lever 11 turning the cam shaft 41. Cam 41a begins to force the cam follower 39 upwards. The position of the rocker and the flow pattern remain unchanged, however, and the motor chamber continues to fill from the left. When the cam is at top dead center, point-to-point with the follower (FIG. 14), the snap-action valve is fully &#34;cocked.&#34; As the cam moves past top dead center, the valve is &#34;triggered&#34; and the follower 39 is urged downward by the compressed springs 40 without opposition (FIG. 15). The downward motion of the follower is unopposed since the cam shaft 41 can turn freely in the rocker until the side of cam 41a engages the side of the U-shaped opening 38b in the rocker. Before the downward traveling follower bottoms out against the upper surface of the rocker 38, the accelerated cam 41a strikes the rocker, thus opening the right inlet port 37 and pivoting the rocker clockwise against the left inlet port 36 (FIG. 16) to stop the flow of water to channel 28. Immediately, the right filling channel 29 communicates with the water pressure in the switch chamber 22a. The motor chamber 18a starts filling from the right, instead of from the left, which starts the paddle-piston 26 turning clockwise for the return cycle. As there is no time at which both channels 28 and 29 are closed off from the water pressure, there is never an interruption in the water service through the nozzles 6, and the rapid positive switching mechanism ensures minimum dwell at the end point of each sweep. 
     ACHIEVEMENTS 
     The major objective and accomplishment of the invention described above is the realization of far wider operating margins without greatly increasing manufacturing costs or sacrificing sprinkler performance. Because of the powerful action of the large area paddle-piston, the resistance of the coil springs in the snap-action toggle valve is easily overcome, whether the water pressure is high or low, over the full range of pressures at which water is usually supplied for residential service. Activation of the toggle valve depends solely on movement of the paddle-piston past a predetermined point. Moreover, once the toggle valve is &#34;tripped&#34; by virtue of passing top dead center, the action of the valve is self-completing under the power of the coil springs, not water pressure. Once switched to the alternate stable position, the rocker can remain there indefinitely, independent of water pressure or the presence of a control stream. Moreover, transient fluctuations in pressure have no effect. As a result, the actuation of the switch requires only enough pressure to keep the paddle-piston moving and maintenance of either stable position is completely independent of water pressure. These attributes allow the sprinkler to be used with assurance in areas with widely varying water pressures. 
     In addition, an improved one-piece, slip-on, wiper flange has been disclosed, which facilitates assembly and further provides a complete double seal operative in the same positive manner in either direction. The new wiper more effectively seals and divides the motor chamber compartments improving the efficiency of the paddle-piston by keeping leakage to a minimum. 
     Finally, a relatively minor disturbance in flow from the sprinkler supply channel into the sprinkler tube has been alleviated by providing integrally with the sprinkler tube, and without additional manufacturing difficulty, a special antivortex van to prevent water from circulating around the outside of the sprinkler tube at the intake port. 
     With these improvements, the sprinkler described above achieves improved performance, greater ease of assembly of certain parts and wider operating margins over varying water pressure conditions without drastically altering the design of the sprinkler or increasing its manufacturing cost, while retaining the paddle-piston-motor feature which ensures maximum reliability in oscillating water sprinklers, the best type of sprinkler for home use.