Robotic lawn sprinkler

An automatic robotic lawn sprinkler providing a water powered, articulated, actuation and control system aiming a continuous stream of water to all coordinates within a polar coordinate system comprising a manually programmable base assembly for anchoring to the ground and containing site specific range data, an azimuth rotor assembly rotatably mounted to the base in a horizontal plane, a range rotor assembly rotatably mounted in a vertical plane substantially perpendicular to the azimuth rotor, an azimuth actuation and control system, range actuation and control system, and a mechanism for variably controlling range rate and flow volume.

FIELD OF THE INVENTION 
The present invention relates to sprinklers for irrigation purposes and 
more particularly to robotic sprinklers programmable to accurately cover 
irregular shaped areas. 
BACKGROUND OF THE INVENTION 
In the past, water has been a plentiful and inexpensive commodity; however, 
it is becoming increasingly scarce and more expensive. Accordingly, past 
sprinklers utilized techniques to approximate uniform coverage by 
overlapping circles and sectors of circles, rectangular shapes and more 
recently irregular shapes; however, the previous art until the present 
invention, has failed to address the shortcomings of the underlying 
approach in dispersing the water. Whether they are impact, rotary or 
oscillating sprinklers, all known sprinklers attempt to produce a more or 
less uniform linear cord of spray and to advance this linear cord in a 
straight or circular path generally perpendicular to this cord. 
Furthermore, to generate these uniform cords of spray, water streams are 
impinged upon objects or forced through small openings to generate small 
droplets and mist uniformly distributed along the length of the cord. 
This method creates a wide range of droplets sizes ranging from large drops 
to a fine mist with the larger drops traveling the greatest distance and 
the smaller drops decelerating quickly and falling short as a result of 
their respective aerodynamics. Even recent sprinklers which claim to cover 
irregular shapes still use a uniform cord of water adjusted in length by 
changing the elevation angle (range) or lowering a shield in front of the 
stream thereby breaking the entire stream into mist. The mist is generally 
lost by drifting in winds and evaporating. 
Furthermore, with these small droplets, it is necessary to thoroughly 
saturate the organic lawn material until water can agglomerate into large 
droplets which make their way down to the soil. All the while, the organic 
matter is maintained in a saturated condition over essentially the total 
area which further increases evaporation. Ultimately, most water left in 
surface vegetation is lost to evaporation instead of being taken in by the 
roots. Losses are further increased because particles of small aerodynamic 
diameters drift and are difficult to accurately direct to the lawn. 
The second aspect of efficiency which the present invention resolves is 
precise pointing. It is this precision which is most obvious to the user 
and consequently represents his main advantage. Perhaps the most 
undesirable characteristic of a watering system is for water to strike a 
building, walk, street or other unwanted area. For irregular shaped lawns, 
to avoid striking unwanted areas the water source must be located at many 
locations. For buried systems this means many separate heads and 
consequently more cost. For portable systems, this means moving the 
sprinkler many times and consequently more wasted user time and more 
inconvenience. 
As an example of control difficulties, a commercial embodiment of U.S. Pat. 
No. 4,637,549 utilizes the lowered screen to prevent excessive range by 
disintegrating large droplets. In addition to the increased evaporation as 
previously described, the stream is diverted into a 30 or 40 degree wide 
wedge which by the manufacturer's own admission makes tight control 
impossible. Other patents cite controlled coverage as their advantage; 
however, it is the failure of these devices to address the fundamental 
deficiencies of the control method which defeats these attempts. 
U.S. Pat. No. 2,757,956 which departs considerably from the other 
references falls far short of the performance of the present invention. 
While Salminen teaches improved efficiency by providing rectangular 
patterns to prevent the required overlapping of circles, he specifies a 
device which is inherently inefficient. To obtain zero range, his device 
discharges water vertically upwards. This produces maximum evaporation, 
dispersion and potential for aiming error. Only a slight breeze or aiming 
error will cause the trajectory to vary greatly from the desired target. 
He addresses only the inefficiency of overlapping circular areas but fails 
to observe the need to follow irregular boundaries while eliminating 
multiple sprinklers and providing precise aiming. The complex needs of the 
field of this invention are not obvious and until the present invention 
have evaded a solution. 
It is precision in range and precision in azimuth which the present 
invention provides to overcome these problems. Precision is provided in 
azimuth by the radial, non-rotary, action of the present invention. By 
indexing azimuth in narrow bands of approximately 3 to 6 degrees, and 
using a "power nozzle" with a comparable angle of dispersion, the present 
invention produces sharp cuts in azimuth. And due to the discrete 
stationary azimuth positions, the device can go from minimum range to 
maximum range and, vice versa within one azimuth increment. By the use of 
variable range angle and/or variable water pressure, the present invention 
provides a maximum to minimum radius (or "turn down ratio") of 5:1 or 
greater. In actuality, by varying the water pressure to a bubble tight 
shut off in several embodiments of the invention, the device can 
completely eliminate water coverage to any desired azimuth positions. 
A valve linked to the range setting within the present invention decreases 
pressure at close in ranges. This has the combined effect of eliminating 
the damaging water blasting of close-in vegetation, decreasing the total 
water applied to the proportionally smaller close in areas, and decreasing 
the range simultaneously. This produces tight radial control and uniform 
watering. 
A further embodiment of the present invention is provided by the addition 
of a second site specific data base. This data base contains information 
regulating the minimum desired range. The combination of the maximum range 
and this minimum range at site specific azimuth angles and a tight 
shut-off valve provides a discontinuous, point watering, system. This 
point watering system waters discrete trees, shrubs gardens and 
architectural landscapes. While existing drip watering and root watering 
systems provide this precision, they do it at extensive cost and extreme 
inflexibility to change the pattern of water distribution. 
This apparatus and control system lends itself equally to above ground or 
buried, "pop-up" sprinkler systems. Within the latter version, the base is 
designed to be buried and a piston device is interstitially configured 
between the base and the azimuth rotor. 
The embodiments of the present invention thereby provide a water powered, 
articulated, actuation and control system which aims a precision, power 
jet, consolidated water stream to all coordinates within a polar 
coordinate system.

DETAILED DESCRIPTION OF THE INVENTION 
In FIG. 1 there is illustrated a robotic sprinkler apparatus 10 for 
watering irregular shaped lawns 100 shown bordered on the sides by 
residence 101, drive way 102, street 103, and area of low water consuming 
plants 104. The structure, actuation means and controls combine to define 
a polar coordinate system with the apparatus 10 forming the pole, the 
nozzle direction defining the azimuthal coordinate 105 and the variable 
trajectory of the water defining the range coordinate 106. 
The preferred embodiment establishes uniform water coverage by indexing 
uniformly in azimuth by the indexing angle 107 and directing the 
trajectory of a stream of water emitting from the nozzle to advance 
uniformly from one radial extreme to the other at that azimuth. Zero range 
is at apparatus 10 and the azimuth specific maximum range 106 is defined 
by the intersection of the radial path of the water and the irregular 
boundary of the watered area. Thus, lawn 100 is uniformly covered by 
wedges of water, azimuth indexing angle 107 wide by azimuth specific 
maximum range 106 long. 
It is appreciated that for uniform water coverage, the dispersion angle of 
the nozzle must correspond to the azimuth indexing angle 107 of the 
apparatus. And further, to maintain uniform water coverage, watering time 
and/or watering flow rate must increase proportionally as range increases. 
The present invention is shown later to do this. 
The maximum range of radial path 108 varies as a function of azimuth 
orientation and the preset, site specific data stored within apparatus 10 
for the respective azimuth direction, as will be later shown. Azimuth 
extremes 109, 110, 111 and 112 likewise are site specific and defined by 
various control means as will be later shown. In that there is no preset 
zero azimuth stored within the device, this setting is site specific and 
to be set by the user or the unit is left to index in the same direction 
through 360 degrees and repeat continuously. 
An alternate embodiment which is not shown in the present patent is the 
rearrangement of elements to establish uniform water coverage by uniformly 
indexing range while advancing azimuth to form uniform arcs with site 
specific extremes. This embodiment can produce equally desirable operation 
but is not preferred due to increased data storage. 
Reference is now made to FIG. 2 which schematically illustrates an 
embodiment of the present invention generally identified at 10 and 
operating in accordance with FIG. 1. The embodiment is comprised generally 
of a nozzle assembly 11 rotatably mounted in a vertical, range, plane upon 
azimuth rotor assembly 13 which is rotatably mounted in a horizontal 
azimuth plane upon base assembly 12. 
Base assembly 12 is comprised of water connection means 43, water 
communication means 44, anchors 42, azimuth indexing pins 45 and 
programmable range stops 46. Said base assembly is typically, though not 
necessarily molded of plastic with azimuth indexing pins 45 and anchors 42 
an integral part of the assembly. However, by definition, said 
programmable range stops 46 are mounted within holes formed within the 
base and having adjustable heights relative thereto. It is this variable 
height relative to the base that forms a mechanical, erasable, 
programmable, read only memory which is analogous to an "EPROM" within 
electrical programmable controllers. This user stored site specific data 
provides range information to the control system which controls the 
maximum boundary outline of the area to be watered. 
Azimuth rotor 13 is rotatably mounted to base 12 on azimuth bearing 15 
which is comprised, generally, of two hollow cylindrical members 
concentrically related and provided with thrust resistant sealing means. 
These bearings are typical of all known rotary sprinklers and can be 
constructed of plastic or metal or a combination of both. Water 
communication means 27 A and B connect index bearing 15 with range bearing 
14 for the communication of pressurized water there between. Range bearing 
14 is identical to index bearing 15. 
Valve 18 is interstitially located between high pressure water 
communication means 27A and controlled pressure water communication means 
27B to control the discharge pressure of nozzle 19 while maintaining high 
pressure control water to needle valve 47 with its inlet positioned to 
communicate with high pressure water communication means 27A, and its 
discharge communicating with hydraulic passage 36. Hydraulic passage 36 
thereafter, communicates with range control actuation means 22, cycle 
reset actuation means 33, and azimuth control actuation means 29, each 
with their respective return springs 16, 35, and 30. Venting valve 23 is 
also in communication with hydraulic passage 36. Venting valve 23 is 
similar to a typical Schrader valve common in tire and inner tube valve 
stems. This valve is shown without its typical closure spring for clarity. 
Advantage is taken of the plurality of actuation means to closely sequence 
operations as will be described later; however, in consideration of the 
practical need to limit wetted parts, subsequent embodiments illustrate 
the limiting of the number of actuation means to a single member. 
Obviously, then, the total number of actuation means is not critical. 
Linkage 28 is a lever fixed at one end to valve 18 and rotatably pinned at 
one end of compressive linkage 20 which is slidably engaged to cam 38. 
Linkage 20 is rotatably pinned at a central location to linkage 34 also 
rotatably pinned to to azimuth rotor assembly 13 to form a four bar 
linkage in order to control the rotational position of linkage 20. Linkage 
21 is rotatably pinned to range rotor assembly 11 at its upper end and to 
range control actuator means 22 at its lower end. Linkage means 31 is 
fixedly connected to range rotor assembly 11 at its shown left end and 
rotatably pinned to one end of linkage 39 which is rotatably pinned to the 
upper end of linkage 48 which slidably engages linkage guide 57A which is 
aligned to direct linkage 48 to strike range stop 46. 
Pawl 17 is rotatably pinned to azimuth rotor assembly 13 and driven by 
compression spring 49 to rotate clockwise into engagement with azimuth 
indexing pins 45 in a manner to override said pins as rotor assembly 13 
rotates clockwise as viewed from above and to bind on said pins as rotor 
assembly 13 attempts to rotate counterclockwise. In like manner pawl 26 is 
rotatably pinned to azimuth control actuator means 29 and driven by 
compression spring 31 to engage said pins 45 when actuator means 29 
extends and override pins 45 when actuator means 29 withdraws. Said 
elements combine to form a ratcheting mechanism for indexing azimuth. 
Linkage 20 is rotatably pinned at its upper end to actuator means 29 and at 
its lower end to sear 24 in such a manner to cause clockwise rotation of 
sear around pin 40 as actuator means 29 extends. This brings sear 24 into 
interference with the path of the linkage lower extreme. It is appreciated 
that sear 24 must be suitably flexible to override as linkage 25 passes 
but rigid enough to sustain engagement of hooked end until actuator means 
29 withdraws. 
Compression spring 32 is rotatably pinned at one end to cycle reset 
actuator means 33 and at the other to linkage 25 which is rotatably pinned 
at its upper end to rotor assembly 13. Said linkages and spring comprise 
an "over center", "snap action" device such that as actuator means 33 
extends, the upper extremity of spring 32 passes through the center line 
projected through spring 32 connection point to linkage 25 and pivot point 
37. The lower end of linkage 25 is designed in barb fashion to override 
sear 24 as linkage 25 rotates counterclockwise and to engage sear 24 as it 
attempts to rotate clockwise. Linkage 25 thus engages vent valve 23 to 
open the valve and maintain it open until actuator means 29 withdraws, 
disengaging sear 24 from linkage 25. 
Generally these linkages, pins, pawls, sear and cam elements are typically 
plastic or metal in construction and designed to suit the application and 
function. 
Range rotor 11 is comprised of range bearing 14, elbow and water 
straightener 41 and nozzle 19. Range bearing 14 is identical to azimuth 
rotor bearing 15. Water straightener 41 and nozzle 19 form a power nozzle 
which issues a smooth stream of water of maximum range, with the most 
concise impact area. 
In FIG. 2 automatic sprinkler apparatus 10 operates in the following 
manner. Azimuth rotor 13 is rotatably mounted to base 12 on azimuth 
bearing 15 and indexed in rotation by azimuth control actuator means 29. 
This actuator means as all other actuator means herein described are 
represented as piston and cylinder actuators although other compression 
actuators like the bellows or diaphragm and tension actuators as described 
in U.S. Pat. No. 2,844,126 are equally applicable and may be substituted. 
Azimuth control actuator means 29 is in hydraulic communication with range 
control actuator means 22 and cycle reset actuator means 33 by means of 
hydraulic passage 36. 
High pressure water is allowed to flow from water communication means 27 
within rotor assembly 13 to hydraulic passage 36 at an adjustable flow 
rate through needle valve 47. 
As water enters passage 36, its pressure is exerted equally on all three 
actuator means (29, 33 and 22). Each actuator means has an individual 
return spring (30, 35 and 16 respectively) each with differing spring 
preloads and spring rates such that the actuators operate in the following 
sequence. As water flows into passage 36, actuator 29 begins extending 
first because its spring is the softest and has the least preload. As 
actuator means 29 extends, pawl 26 presses against azimuth indexing pin 45 
causing azimuth rotor to index clockwise when viewed from above apparatus 
10. Pawl 17 rides over its respective pin 45 to prevent counter rotation 
as described later. As actuator means 29 bottoms out at its full travel, 
pressure in passage 36 increases until spring 16 and friction of valve and 
range bearing are overcome by the force of range control actuator means 
22. As actuator means 22 extends, valve 18 is opened by the action of 
linkages 28 and articulated linkage 20A and cam 38 while linkage 21 causes 
range rotor assembly 11 to rotate about range bearing 14, increasing its 
superelevation until range stop 46 is struck by linkage 48. 
Range stop 46 is adjustable to its lowest setting which allows nozzle 
assembly 11 to assume its maximum theoretical range angle of 45 degrees 
superelevation. In actuality, however, a practical range angle extreme of 
about 38 degrees provides a range immeasurably close to that of 45 degrees 
while conserving linkage sizing. At this maximum range position, valve 18 
is full open and the device is producing the maximum range possible given 
the site specific water flow and pressure conditions. 
Range stops 46 are adjustable to their highest setting which prevents valve 
18 from opening. At this position, the device cycles in azimuth without 
discharging water from nozzle 19. Thereby, sections of area are left 
completely omitted from watering. These sections may correspond to 
buildings, pavement or other areas which are desired to receive no water. 
At most times, however, range stops 46 are set between their highest and 
lowest positions to correspond to the exact range desired at each specific 
azimuth positions. Basically there is a single range stop provided for 
each respective azimuth increment. (i.e., there are the same number of 
equally spaced range stops 46 as there are azimuth indexing pins 45). The 
particular setting of range stop 46 provides the combined valve 18 
position and nozzle 19 superelevation to result in the desired range. 
When linkage 48 strikes stop 46, actuator means 22 is prevented from 
extending further. Pressure within passage 36 increases until spring 35 is 
overcome and reset actuator means 33 extends. Actuator means 33, 
compression spring 32 and linkage 25 combine to form a "snap action" or 
"over center" device to open valve 23. As actuator 33 extends, compression 
spring is further compressed until it passes over pivot point 37 of 
linkage 25 at which point linkage 25 reverses position engaging sear 24 
and opening valve 23. Valve 23 is similar to a standard Schrader valve and 
is retained open until each piston returns to its initial position, in 
reversed order, discharging the working volume of water from passage 36. 
Actuation means 33 is first to return to its initial position followed by 
22 and then 29. As pawl 17 engages azimuth indexing pin 45 to prevent 
counter rotation, actuator means 29 reaches its initial position causing 
sear linkage 24 to rotate counterclockwise disengaging linkage 25. As 
linkage 25 rotates clockwise, valve 23 closes building up pressure to 
repeat the control sequence. 
The specific configuration of linkages 31, 18, 28 and 20 plus cam 38 are 
designed appropriately to control range rate and water discharge rate to 
produce uniform water coverage. In like manner, advantage is taken of the 
fact that as the diameter of the actuator means decreases, the area 
decreases by the square of this decrease and consequently, the speed of 
actuation of the respective actuation means increases by this squared 
ratio. Thereby, the diameters of actuation means 29 and 33 are reduced to 
the minimum required for their respective operations, thus maintaining 
azimuth indexing at a minimum elapsed time. 
In FIG. 3 is schematically illustrated an alternate embodiment of robotic 
sprinkle apparatus 10 which has been modified to use only one actuator 
means and to accomplish all sequential operations by altered linkages, 
having the advantage of less wetted parts. Base 12 and range rotor 
assembly 11 are identical to those illustrated in FIG. 2 with the 
exception of the location of linkage connection points. Within this 
embodiment the raised, maximum range, position of range rotor 11 is 
achieved during the vented condition of water passage 36 and the 
horizontal position, at the end of the pressurizing cycle of passage 36. 
Ratchet wheel 59 has been added to provide compact indexing and to 
facilitate a later described reversing embodiment of the present 
invention. Ratchet pins 60 are integrally molded to or attached to wheel 
59. The lower end of compression linkage 64 provides the function of 
azimuth control actuator means and pawl 26. Pawl 17 and spring 49 are 
modified slightly as are the "over center" device comprising tension 
spring 32A, linkage 25A and pivot point 37 of linkage 25A on azimuth rotor 
assembly 13. Linkage 64 is rotatably pinned to linkage 63 which is 
rotatably pinned to range rotor assembly 11 at pin 62. Thereby the 
rotation of range rotor assembly 11 provides the motive force for azimuth 
indexing. 
New linkages 52, 55 and 56 are added to release sear 24. Linkage 52 is 
fixedly connected to range rotor assembly 11 at one end and rotatably 
pinned at pin 61 to spring 16, linkage 55 and linkage 21. Linkage 55 is 
rotatably pinned at upper end of linkage 39. 
The operation of the embodiment illustrated within FIG. 3 is described 
within the following sequence. Water enters sprinkler 10 at inlet 43 and 
is discharged through main nozzle 19 or through control needle valve 47 in 
identical manner as described for FIG. 2. As water passes through needle 
valve 42 and enters water passage 36 it operates a single actuation means 
22. As actuation means 22 moves upward, cam 38 moves linkage 20 to the 
right, rotating valve control linkage 28 clockwise, closing the valve (not 
shown) which is inside rotor assembly 13 in like manner to the description 
of FIG. 2. Linkage 34 has been provided within this embodiment to create a 
"four bar linkage" controlling the rotation of linkage 20 as it 
translates. 
As linkage 21 moves upward, with actuation means 22, pin 61 travels upward 
in an arc around range bearing 14 at the end of linkage 52 rotating range 
rotor 11 toward horizontal. Linkage 55 rotates counter clockwise while pin 
54 and linkage 39 travel upward, and linkage 48 slides within guide 57. In 
similar manner to the description of FIG. 2, valve 18 position, nozzle 19 
direction, and range rate are coordinated to provide uniform radial water 
distribution. 
Counterclockwise rotation of range rotor 11 forces pin 62 and linkages 63 
and 64 downward. Linkage 64 lowers without rotation through linkage guides 
57. The lower end of linkage 64 strikes pin 60 which rotates ratchet wheel 
59 counter clockwise. As pawl 17 under the force of spring 49 overrides 
and secures another pin 67 on ratchet wheel 59, azimuth rotor 13 advances 
one azimuth index 107 as described in FIG. 2. As indexing occurs, spring 
pin 65 at the end of tension spring 66 moves through the center between 
pin 37 and spring pin 65A which results in rapid counter clockwise 
rotation of linkage 25 about pin 37. The lower end of linkage 25 engages 
sear 24 while depressing the stem of valve 23 (valve spring not shown). 
Spring 53 maintains sear 24 engages with linkage 25 until 63A is released 
as described later. Since water discharges more rapidly out of valve 23 
then it enters through needle valve 47, passage 36 is vented, allowing 
spring 16 to return all linkage to their original positions. 
When linkage 48 strikes range stop 46 pin 54 becomes stationary and the 
instant center of rotation of linkage 55. This is to say that pin 61 
continues to move down while pin 54 is stationary in this manner, the left 
hand end of linkage 55 forces linkage 56 down, sliding within guide 57C. 
The bottom end of linkage 56 forces sear 24 down thus disengaging linkage 
25 which releases valve 23 to close (valve spring not shown). Thus the 
cycle starts over. 
Since there are portions of lawn and surrounding features which are desired 
to remain dry, the apparatus is featured with a by pass operating mode for 
these areas. Within this mode, valve 18 is held tight closed while sear 24 
is restrained from contacting linkage 25 thus allowing rapid dithering of 
linkage 25 sufficient to operate azimuth indexing without opening valve 
18. Specifically, range stop 46 is set to its highest position. At this 
position range rotor is driven to minimum range stop 90 and the action of 
ratchet wheel 59 indexes azimuth rotor assembly 13 thus driving linkage 48 
against stop 46. The curvature of the contact surfaces of linkage 48 and 
stop 46 are sufficient to ramp 48 up over 46. With range rotor fixed 
against range stop 90 and consequently pin 61 stationary at its highest 
position, linkage 55 is forced to rotate ccw about pin 61 causing its left 
hand end 55A to depress linkage 56 holding seat 24 out of contact with 
linkage 25. 
In this position, linkage 25 rotates into contact with valve 23 discharging 
water which allows spring 16 to start range rotor rotating clockwise. 
However with linkage 48 held stationary. linkage 56 is further depressed 
as pin 61 lowers under the rotation of linkage 52, thus holding sear 24 
open. As soon as pin 65 passes above the center line between 65A and 37, 
linkage 25 snaps out of contact with valve 23 causing apparatus to cycle 
without the opening of valve 18 because cam 38 is flat in a vertical 
position which does not start the opening of valve 18. Pressure starts 
increasing in fluid 36 which rotates range rotor 11 ccw depressing linkage 
64 to index ratchet wheel 59 and rotate linkage 25 ccw depressing valve 
23. In this manner azimuth is indexed while valve 18 is held closed. As an 
azimuth position is reached where setting is lower than the by pass 
position, operation continues in the normal watering mode. 
In FIG. 4 there is schematically illustrated a robotic sprinkler apparatus 
10A for watering irregular shaped lawns 100 shown bordered on the sides by 
residence 101, drive way 102, and street 103, which is similar to FIG. 1 
except the embodiment shown at 10A is designed as illustrated later in 
FIG. 5 for spot watering. Within this embodiment, the structure, actuation 
and control means coordinate to form a polar coordinate system with the 
apparatus 10A forming the pole, the nozzle direction defining the 
azimuthal coordinate 105 and the variable trajectory of the water defining 
the range coordinate 106 as in FIG. 1. Except, within this embodiment, is 
included the control means to store minimum range data to enable the 
coverage of discrete areas which are not in contact with the sprinkler 
apparatus. 
Within the preferred embodiment, uniform water coverage is established by 
indexing uniformly in azimuth by the angle 107 while range is controlled 
to define a uniform locus of points which form a radial path of water 
impact 108. The maximum range of radial path 108 (farthermost extreme of 
radial path from apparatus 10A) varies as a function of azimuthal 
orientation and the preset, site specific data stored within the base of 
apparatus 10A for the respective azimuth direction. Within the embodiment 
illustrated at 10A is included also the means of limiting the minimum 
range of 110. The azimuth extremes (108, 109 and 108', 109' likewise are 
site specific and defined by various control means as will be later shown. 
In that there is no preset zero azimuth stored within the device, this 
setting is site specific and to be set by the user or the unit is left to 
index continuously 360 degrees and repeat. 
In FIG. 5 is schematically illustrated an alternate embodiment at robotic 
sprinkler apparatus 10A which has been modified for spot watering as was 
illustrated in FIG. 4. This operation is provided by the addition of an 
adjustable minimum range stop 69 and linkages 67 and 68 and elimination of 
linkage 63 to recycle the actuation means at site specific minimum ranges 
in a similar manner to the maximum range components. 
In operation, 10A initiates it's cycle at maximum range with linkage 48 
stationarily obstructed by stop 46, forcing sear 24 from engagement with 
linkage 25, and proceeds toward minimum range in identical fashion to 
apparatus 10. However, within apparatus 10A, range stop 69 is field 
adjusted by the user to cause the mechanism to recycle at the desired site 
specific minimum range instead of zero range as in apparatus 10. As range 
rotor 11 moves counter clockwise linkage 67 lowers, causes linkage 68 to 
lower until it contacts stop 69. The left end of linkage 68 is fixedly in 
contact with stop 69 at 68', and 67 continues downward, moving pin 92 
downward with it. Correspondingly pin 91 moves linkage 64 down. As pin 65 
on linkage 64 moves down through the center line between pins 37 and 65A, 
linkage 25 "snaps" ccw opening valve 23 and engages sear 24 while the 
bottom end of 64 rotates ratchet wheel 59 indexing azimuth incrementally. 
Valve 23 continues venting control water allowing spring 16 to return 
device to deenergized condition. The contact of linkage 48 and 46 starts 
the cycle again as described earlier. 
FIG. 6 and FIGS. 7A and 7B illustrate embodiments of the present invention 
which combine valve 18 and range rotor assembly 11 thus eliminating 
linkages. FIG. 6 illustrates a slide valve assembly which is not 
necessarily water tight while the pinch valve of FIG. 7A and 7B is water 
tight. 
In FIG. 6 is illustrated upper portion of azimuth rotor 13 and range rotor 
assembly 11 modified to incorporate slide valve 71. Slide valve 71 is 
comprised of orifice plate 51A which is fixedly attached to outer race of 
range bearing 14 which, in turn, is fixedly secured to azimuth rotor 13, 
and orifice plate 51B which is fixedly attached to inner race of bearing 
14 which is free to rotate with range rotor assembly 11. Orifice plates 51 
A and B are comprised of circular disks with orifices 70 radially disposed 
at equal radii and circumferentially disposed at 90 degree increments. The 
size of orifices 70 are such that the land between adjacent orifices is 
larger than the orifice. Thus at minimum range which is illustrated within 
FIG. 6, the lands of orifice plate 51A are covering the orifices of 51B 
and conversely 51B covers 51A. As 51B rotates clockwise as range rotor 
moves to maximum range at 45 Degrees, orifices 70 on both orifice plates 
51A and 51B continually move toward alignment which occurs at 45 degrees. 
Thereby the flow area varies from zero at zero range and maximum at 45 
degrees. All other functions of this embodiment are as previously 
described according to the desired operation. 
FIGS. 7A and 7B illustrate a final embodiment combining range rotor 
assembly 11 and valve 18. FIG. 7A illustrates the assembly at maximum 
range and full flow and FIG. 7B illustrates the assembly at zero range and 
zero flow rate. Range rotor assembly 11A is comprised of flexible pressure 
conduit 40, anvils 50 and 50A, and linkage 52A which cooperate to form a 
pinch valve. In operation within FIGS. 7A water flows freely within 
flexible pressure conduit 40 from inlet end attached to azimuth rotor 13A 
and discharges through nozzle 19 which is connected to the discharge of 
flexible pressure conduit 40. Within FIG. 7B water flow is illustrated as 
restricted and ultimately pinched off by the movement of anvil 50 downward 
and against anvil 50A as linkage rotates counterclockwise about pivot 
point 72. The pressure exerted by 50 on 50A pinches off the water flow. 
Again, the other operating parameters are unchanged from previous 
embodiments. 
FIG. 8 illustrates an embodiment of the present invention which perhaps 
sacrifices performance somewhat for the obvious economic advantage of 
eliminating range rotor assembly 11. Within this embodiment, a plurality 
of nozzles 19 are fixedly mounted in range angle to azimuth rotor 13B 
eliminating range rotor assembly 11. Each of the plurality of nozzles 19 
are provided with hydraulic passages 36A designed to dissipate water 
pressure while producing desired turbulence and rotation of water to 
cooperate with its respective range angle to provide the desired range and 
water dispersion. To gain the maximum range and accuracy, the top nozzle 
19 is superelevated 45 degrees above the horizon and provided full 
pressure with minimum turbulence. The pattern produced by each nozzle is 
designed to overlap that of other nozzles to create a continuous pattern 
which can be progressed uniformly from minimum to maximum range at each 
specific azimuth angle. 
In operation, this device exhibits the same accuracy of control and turn 
down which is typical of the previous embodiments. The apparatus sits 
stationary in azimuth while valve 18 operates over its pre-set site 
specific range until its maximum range is reached. In this case, maximum 
range is coincident with maximum pressure associated with the maximum open 
position of valve 18. In this case range operation is accomplished by 
range actuation means 22, not shown, operating in identical manner to 
previous embodiments with the exception that there is no range rotor 
assembly to operate. Azimuth is operated identically to other embodiments, 
thus providing the typical radial operation of the apparatus which 
distinguishes it from all other known devices. 
This apparatus and control system lends itself equally to above ground or 
buried, "pop-up" sprinkler systems. Within the latter version, the base is 
designed to be buried and a typical water actuated piston device is 
interstitially configured between the base and the azimuth rotor to pop 
the rotor up when in operation. While this style is not illustrated, a 
typically conical shape is anticipated with a lid and openings for setting 
range spaced around the upper rim of the base. A cap ring with inserts to 
snap into the said openings would prevent plugging of range data settings. 
One final embodiment which is incorporated by description but not 
illustrated is a spring returned version which does not rotate 
continuously in a single direction; but, is returned by counter-rotating 
in azimuth to an original position. Within this embodiment, the azimuth 
rotor is advanced in a fashion identical to the previous descriptions; 
however, a clock spring connected at one end to the base and to the 
azimuth rotor at the other, resists the advancement of said rotor. The 
ratchet wheel 59 prevents counter-rotation. Within this embodiment, 
however, said ratchet wheel is split into an input ratchet plate and an 
output ratchet plate connected by a spring loaded clutch plate. This 
spring loading device is an over-center "snap-action" device which is 
normally engaged. As the azimuth rotor advances, a lever engages a 
tripping device mounted upon said base and disengages clutch at a user set 
location. Rotor rotates back to its initial orientation at which point 
another preset tripping device engages clutch to secure rotor and start 
cycle over.