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Description  |
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FIELD OF THE INVENTION
The present invention relates to rotary sprinklers for irrigation purposes
and more particularly to rotary sprinklers capable of covering
non-circular patterns.
BACKGROUND OF THE INVENTION
Rotary sprinklers capable of covering non-circular patterns are well known
in the art and are constructed on the basis of a number of operational
principles. Many of the sprinklers of this type employ a cam which
operates a mechanism for governing the range of the spray as a function of
the azimuthal angle of the nozzle with respect to a set of coordinates
defined with respect to the sprinkler base.
One type of cam operated sprinklers employs a cam operated valve for
governing the water flow to the sprinkler as a function of the azimuthal
orientation of the nozzle. This type is exemplified in the following U.S.
Pat. Nos. 2,824,765; 3,528,093; 3,878,990; 3,884,416; 2,739,839;
2,600,987; 4,119,275; 2,884,202; 3,881,655; 2,780,488. Another type of cam
operated sprinkler employs a cam operated device for changing the angle of
elevation of the nozzle. This type is exemplified by the following U.S.
Pat. Nos.: 2,475,537; 3,952,954; 2,979,271; 3,960,327; 3,091,399.
Yet another type of cam operated sprinklers employs an auxiliary nozzle
U.S. Pat. Nos. 2,835,529 and 2,459,244 illustrate such a construction.
Still another type of cam operated sprinklers employs a cam-operated
deflector for producing a non-circular pattern. This type is exemplified
by U.S. Pat. Nos. 4,191,331; 2,654,635; 3,654,817; 2,565,926.
Other patents of interest in this field, including patents which show
apparatus for converting rotary sprinklers from part circle to whole
circle operation include the following U.S. Pat. Nos.: 2,944,743;
3,841,563; 3,874,588; 3,924,809; 3,918,642; 3,921,912.
SUMMARY OF THE INVENTION
The present invention seeks to provide an improved type of rotary sprinkler
which is capable of covering a non-circular pattern.
There is thus provided in accordance with an embodiment of the invention a
rotary sprinkler comprising a housing arranged for connection to a
pressurized water supply; a stem mounted in the housing for rotation
relative thereto; a water discharge nozzle mounted on the extreme outer
end of the stem and being rotatable together therewith relative to the
housing; water driven drive apparatus for rotating the stem relative to
the housing, selectably positionable deflector apparatus for engaging a
stream of water emitted by the nozzle for determining the maximum radius
of the stream, cam apparatus for operating the deflector apparatus and
determining the maximum radius of the stream as a function of the
azimuthal orientation of the nozzle, which function is determined by the
cam, the cam apparatus comprising a first biasing device for determining
the outer radius of a circle within which a desired pattern is to be
defined and a second biasing device for defining the pattern within the
circle.
Further in accordance with an embodiment of the present invention, the
deflector apparatus comprises a water engaging portion and a cam following
portion rigidly joined to the water engaging portion and is pivotably
mounted about a pivot location. The pivot location is variable in
accordance with the setting of the first biasing device.
Additionally in accordance with an embodiment of the present invention, the
first biasing device is operative to govern the geometrical relationship
between displacements of the cam following portion and the water engaging
portion.
Further in accordance with an embodiment of the present invention, the
first and second biasing devices are operated by a single dial which is
rotatable relative the stem for setting thereof and is rotatable relative
to the housing during operation of the sprinkler.
Additionally in accordance with an embodiment of the present invention,
there is provided means for selectably limiting the azimuthal range of
sprinkler rotation. According to a preferred embodiment of the invention,
the limiting means comprise selectably displaceable protrusions whose
orientations visually indicate the azimuthal range of sprinkler operation.
Further in accordance with an embodiment of the invention, apparatus is
provided for preventing operation of the sprinkler in the undesired range
of operation or in an undesired mode of operations.
Additionally in accordance with an embodiment of the present invention, the
azimuthal limiting means are provided on concentric rings mounted onto the
housing.
Additionally in accordance with an embodiment of the present invention,
means are provided for selecting a non-circular pattern, such as a square
pattern, and then rotating it as desired.
Further in accordance with an embodiment of the present invention, the
pivot mounting location of the deflector apparatus is mounted on an
intermediate link which is itself pivotably mounted at a location fixed
with respect to the sprinkler stem.
Additionally in accordance with an embodiment of the invention, the cam
following member may be operative to angle of the nozzle or to control the
supply of liquid to the nozzle in response to a cammed program. These
functions may be in combination with or in place of movement of the
deflector into the nozzle output stream.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more fully understood and appreciated from
the following detailed description taken in conjunction with the drawings
in which:
FIG. 1 is a sectional illustration of a rotary sprinkler constructed and
operative in accordance with an embodiment of the present invention;
FIG. 2 is nozzle facing side view illustration of the sprinkler of FIG. 1,
partially disassembled;
FIG. 3 is a hammer side facing side view corresponding to FIG. 2;
FIG. 4 is a cam follower side facing side view corresponding to FIGS. 2 and
3;
FIG. 5 is a rear side facing side view corresponding to FIGS. 2, 3 and 4;
FIG. 6 is a side view of the fully assembled sprinkler corresponding in
orientation to FIG. 4;
FIG. 7 is a top view of the fully assembled sprinkler of FIG. 6;
FIG. 8 is a top view of the sprinkler head of the preceding drawings;
FIGS. 9A, 9B, 9C and 9D are sectional illustrations taken along a line
corresponding to the line IX--IX shown on FIG. 1 of a sprinkler
constructed and operative in accordance with an embodiment of the
invention in a plurality of different orientations;
FIGS. 10A, 10B, 10C and 10D are sectional illustrations taken along a line
corresponding to the line IX--IX shown on FIG. 1 of a sprinkler
constructed and operative in accordance with an alternative embodiment of
the invention in a plurality of different orientations;
FIGS. 11A, 11B, 11C and 11D are sectional illustrations taken along a line
corresponding to the line IX--IX shown on FIG. 1 of a sprinkler
constructed and operative in accordance with still another embodiment of
the invention in a plurality of different orientations;
FIG. 12 is a side view illustration of the azimuth limiting apparatus also
illustrated in FIGS. 11A-11D;
FIGS. 13A and 13B are respective plan view and sectional illustrations of a
function governing cam member, the plan view illustrating the underside
surface of the cam member, indicating the cam configurations thereon;
FIG. 14 is a pictorial illustration of an alternative embodiment of finger
element and corresponding stop members;
FIG. 15 is a pictorial illustration of an alternative embodiment of zone
defining protrusions;
FIGS. 16, 17 and 18 are respective side, vertical sectional and horizontal
sectional illustrations of a sprinkler constructed and operative in
accordance with an alternative embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference is now made to FIGS. 1-8 which illustrate a sprinkler constructed
and operative in accordance with an embodiment of the present invention.
The sprinkler comprises a base 10, typically formed of plastic and which
defines a generally vertical rotation axis 12 about which a sprinkler head
13 rotates.
Base 10 may be a unitary member or alternatively, as illustrated in the
drawing, may be formed of a plurality of separate members. Base 10 may
also be mounted onto a stabilizing basis member (not shown) of any type
such as a wide base or a spike. The basis member may or may not include a
water supply conduit. As a further alternative a lower portion 14 of the
base 10 may be eliminated and a water supply connection may be made
directly with an upper portion 16 of the base, by conventional techniques.
Rotatably mounted onto upper portion 16 for generally free rotation
relative thereto about axis 12 is a stem block 18, also typically formed
of plastic.
Stem block 18 defines a water passage channel 20 which communicates via a
conduit 24 defined in lower portion 14 of base 10 with a water supply
inlet 26. Channel 20 terminates in an angled nozzle portion 28. It is
noted that although the present illustration shows nozzle portion 28
arranged at a fixed angle with respect to axis 12, it is also possible in
an alternative embodiment of the invention to construct the nozzle portion
to have a variable angular orientation with respect to axis 12. This
alternative embodiment is desirable when it is desired to vary the angle
of water ejection in accordance with a predetermined program in order to
produce a particular sprinkler pattern.
An axial stem pin 30 is fixedly mounted onto stem block 18 and typically
extends along axis 12, thus defining a bearing surface for the remaining
elements of the sprinkler head 13, which are rotatable relative thereto.
Rotatably mounted about stem pin 30 is a hammer 32 including a collar
portion 34 which surrounds pin 30. Connected to collar portion 34 is an
intermediate portion 38. The intermediate portion 38 is connected at one
end to a deflector 40, which defines a flow through pathway for water
exiting under pressure from the nozzle portion 28, and at the opposite end
to a weight 41. Preferably, the entire hammer 32 is formed integrally as a
single plastic element.
Disposed in surrounding relationship with stem pin 30 above collar portion
34 is an extension 42 of stem block 18 which is preferably integrally
formed therewith. Adjacent the top surface of extension 42 there is
defined a spacer ring 43 which defines a bearing and rotating surface for
a sprinkler radius defining cam member 44. Cam member 44 is integrally
formed with a function selecting dial 45, whose face is illustrated in
FIG. 7. The underside of cam member 44, which defines the cam surfaces, is
illustrated in FIGS. 13A and 13B.
Referring briefly to FIGS. 13A and 13B, it is seen that the cam member 44
defines first and second cam surfaces 46 and 48. Both of the first and
second cam surfaces 46 and 48 are typically defined as peripheral edge
surfaces, it being appreciated that other types of cam surfaces may
alternatively be provided. First cam surface 46 is preferably a toothed
surface for precise positioning, while cam surface 48 is typically a
smooth surface. As will be explained hereinafter in greater detail, first
cam surface 46, of relatively small circumference, is used to selectably
position a portion of a deflector assembly for non-circular pattern
operation and the second cam surface 48 is used to selectably position a
portion of the deflector assembly for circular pattern operation.
The deflector assembly will now be described in detail. The deflector
assembly, indicated generally by reference numeral 50, comprises a pattern
defining cam follower 52, typically embodied in a roller which is
rotatably mounted onto a support arm 54, which in turn defines a
perpendicular extension of a cam follower support arm 56. Cam follower
support arm 56 is rigidly mounted onto a deflector 58 which is configured
to engage from above a stream of water issuing from nozzle portion 28. It
is appreciated that elements 54, 56, and 58 define a rigid unit and may be
formed unitarily.
Deflector 58 is pivotably mounted at a pivot location 60 onto an
intermediate member 62, which is itself pivotably mounted at a pivot
location 64 onto stem block 18. It may thus be appreciated that the pivot
location 60 is movable with respect to the base, nozzle portion and stem
block. Normally pivot location 60 lies above the the water stream exiting
from the nozzle portion. Alternative designs wherein this is not the case
are also possible.
It is noted that deflector 58 is formed with a radially inward facing
surface 66 which engages the second cam surface 48, while intermediate
member 62 is formed with a radially inward facing surface 68 which engages
the first cam surface 46. It may be appreciated that engagement of surface
68 of the intermediate surface with the first cam surface changes the
angular relationship between the cam follower 52 and the deflector 58,
while the the engagement of surface 66 of the deflector with second cam
surface 48 is operative to pivot the deflector about pivot location 60 and
thus to determine whether the cam follower 52 is in engagement with a
pattern defining cam.
The pattern defining cam is provided, in accordance with a preferred
embodiment of the present invention on the inside circumferential surface
70 of a ring 72 which is removably and rotatably mounted onto base 10. The
cam defining ring 72 may be selectably locked in a predetermined azimuthal
orientation by means of engagement means, such as a screw 74.
The general operation of the deflector assembly 50 will now be described.
Deflector assembly 50 is responsible for determining the pattern of spray
and the size of the pattern. In accordance with a preferred embodiment of
the present invention, the function setting dial illustrated in FIG. 7
illustrates a number of selectable patterns, being squares of different
sizes and circles of different sizes, the circles of each size having a
diameter equal to the diagonal across the respective squares.
When squares are selected, the engagement between the first cam surface 46
and the following surface 68 controls the disposition of the deflector 58,
there being no contact between the second cam surface 48 and the following
surface 66. When circles are selected, the engagement between the second
cam surface 48 and the following surface 66 governs the disposition of the
deflector, there being no change in the radius of the first cam surface
over this range, thus maintaining pivot location 60 in a constant
position. When circles are selected, the cam follower 52 is out of
engagement with the pattern defining cam on surface 70. The size of the
circle is determined solely by the engagement between the second cam
surface 48 and the following surface 66.
When squares are selected, the cam follower 52 engages the pattern defining
cam for determining the square shape. The overall size of the square is
determined solely by engagement of the first cam surface 46 with the
following surface 68.
It is appreciated that the orientation of the square may be selected by
simple rotation of ring 72 with respect to base 10.
It is also a particular feature of the present invention that the sprinkler
has means for providing coverage over only a selected portion of a circle
or of a corresponding angular segment of a square defined therewithin. The
apparatus for providing this function will now be described in detail. It
is noted that when rotary sprinklers operate in a "zone" mode, i.e.
producing less than 360 degree coverage, they produce different types of
sprays as they rotate in different directions. When they operate in what
shall be termed a "forward" direction, a combination long range and short
range spray is produced by full range periodic deflection of a hammer like
deflector, (indicated by reference numeral 40 in the present
specification). When the sprinkler operates in a "return" direction,
opposite to the forward direction, the amplitude of hammer deflector
motion is restricted, normally producing a short range spray only.
A particularly useful type of rotary sprinkler having this feature is
described and claimed in U.K. Published Patent Specification No. 2079632
of the present applicant.
The apparatus for providing "zone" mode operation of the sprinkler and for
governing its operation in forward and rearward directions comprises a
hammer deflector amplitude limiting element 80 which is pivotably mounted
onto stem block 18, about a pivot axis 82 which is parallel to axis 12. A
limiting function control finger element 84 is mounted onto stem block 18
for pivotable rotation about a pivot axis 86 which is also parallel to
axis 12. Finger element 84 is coupled to limiting element 80 by means of a
coil compression spring 85 which is arranged in an over center
configuration so as to cause the limiting element to be maintained in an
engaged orientation with an engagement portion 88 of the hammer deflector,
when the finger element is in an extended orientation and to cause the
limiting element to be in a disengaged orientation with engagement portion
88 when the finger element 84 is in a retracted orientation.
A pair of concentric relatively rotatable rings 90 and 92 are provided in
selectably locking engagement with ring 72. These rings, which serve to
define the azimuthal range of desired sprinkler operation, are provided
with protrusions 94 for manual manipulation of the rings and desired
positioning othereof. It is a particular feature of the present invention
that the orientation of the protrusions 94 visually defines the angular
boundaries of the area of sprinkler operation. Rings 90 and 92 are
provided with radially inwardly facing stop members 96 and 98 respectively
which operate to engage finger element 84 and to change its orientation.
By changing the orientation of finger 84, the forward or return direction
of operation of the sprinkler is selected as appropriate for providing
back and forth motion of the sprinkler between the angular limits of
azimuthal rotation defined by protrusions 94. A number of different
embodiments of stop members 96 and 98 are proposed herein and will be
discussed hereinbelow with reference to FIGS. 9A-11D and 12.
All of FIGS. 9A-11D are partially pictorial, partially sectional
illustrations of part of the sprinkler apparatus of FIG. 1 taken generally
in a plane extending horizontally through the bottom of pin 30
perpendicularly to axis 12. The embodiment shown in FIGS. 9A-9D includes
two stop members 96 and 98, one of which, member 96, is fixed, while the
other, member 98, is selectably positionable into or out of potential
engagement with finger element 84. Selectably positionable stop member 98
may be spring biased by an external spring or by an internal spring
constituted by its plastic construction and disposition in accordance with
conventional teachings well known in the art, so as to adopt an at rest
position in potential engagement with finger element 84 in the absence of
externally applied forces. The remainder of the elements shown in FIGS.
9A-11D are indicated by the same reference numerals as used in the above
description in connection with FIGS. 1-7. FIGS. 9A and 9B illustrate the
sprinkler of FIG. 1 in a full circle mode of operation. Protrusions 94 are
therefore shown in adjacent near registration. FIG. 9A illustrates the
sprinkler operating in a forward direction indicated by the arrow, wherein
amplitude limiting element 80 is in a disengaged orientation with respect
to the engagement portion 88 of the hammer deflector and accordingly the
finger element 84 is in a retracted orientation.
FIG. 9B illustrates operation in a return direction wherein the finger
element 84 is in an extended orientation, causing amplitude limiting
element 80 to engage engagement portion 88 of the hammer deflector and
thus to limit its amplitude, producing return motion. It is noted that in
this embodiment, the finger element 84 engages the stop member 96 and is
caused to retract, thus shifting to forward direction operation. The
orientation of elements shown in FIG. 9B thus occurs only when the
sprinkler is shifted from zone operation to full circle operation, when
the sprinkler head is oriented for return operation. It is thus
appreciated that such operation in a return direction will continue only
until such time as the finger element 84 engages the stop members 96 and
98, i.e. less than one full revolution. Thereafter the sprinkler will
continue in forward operation, since the finger element, once retracted,
will not engage the stop members 96 and 98. It is noted that in the
embodiment of FIGS. 9A and 9B, selectably positionable stop member 98 is
in a retracted, radially outward orientation. This is due to the fact that
the two stop members are in side by side registration, stop member 96
forcing stop member 98 to assume a retracted orientation.
FIGS. 9C and 9D illustrate the operation of the sprinkler in a zone mode,
when protrusions 94 are angularly separated from each other and indicate
the zone of sprinkler coverage boundaries as extensions of the lines which
connect axis 12 to the individual protrusions 94. Here, since stop member
96 does not butt up against the rear surface of stop member 98, stop
member 98 is free to assume its normal, at rest, orientation, whereby it
extends radially inwardly, as illustrated.
In FIG. 9C, return motion of the sprinkler is illustrated, with the
limiting element 80 being in engagement with the engagement portion 88 of
the hammer deflector thus limiting its amplitude and the finger element 84
being in an extended orientation. It is appreciated that the finger
element 84 engages stop member 96 for limiting the zone of sprinkler
coverage and changing direction.
FIG. 9D illustrates forward motion of the sprinkler, with the finger
element 84 in a retracted orientation and the limiting element 80 being
out of engagement with the engagement portion 88 of the hammer deflector.
It is appreciated that the finger element 84 engages stop member 98 in its
radially inward extended orientation.
Reference is now made to FIGS. 10A-10D in which both stop members 97 and 98
are selectably positionable and normally biased into a radially inward
orientation. Thus both of the stop members 97 and 98 are similar in
construction and operation to the stop member 98 illustrated in FIGS.
10A-10D and described hereinabove.
FIGS. 10A and 10B illustrate full circle operation of the sprinkler where
protrusions 94 are nearly in registration. It is appreciated that they
cannot be placed in complete registration due to the provision of
selectably positionable stop members 97 and 98, which abut in side by side
registration in the illustrated orientation. It is noted that this
mutually abutting side by side registration forces both stop members 97
and 98 into their retracted radially outward orientations, as illustrated.
FIG. 10A illustrates return motion wherein the finger element 84 is
extended and the limiting element 80 is in engagement with the engagement
portion 88 of the hammer deflector. FIG. 10A illustrates that in return
motion the finger element 84 engages the stop members 97 and 98 even when
they are in their retracted orientation, thus shifting the sprinkler to
forward motion. Thus whenever full circle operation is indicated by side
by side registration of the stop members, the sprinkler will operate in
forward motion after no more than one revolution in the return direction.
FIG. 10B illustrates forward motion in a full circle mode. Here the finger
element 84 is retracted and thus does not engage the stop members 97 and
98 in their retracted orientation. The sprinkler continues to operate in
the full circle mode.
FIGS. 10C and 10D illustrate operation of the sprinkler in a zone mode,
where protrusions 94 indicate the zone of coverage as described
hereinabove. In FIG. 10C forward direction operation is illustrated, with
the finger element 84 in a retracted orientation. Stop member 98, which is
in its extended orientation, engages the finger element 84 at the zone
limit defined thereby and shifts the sprinkler to return operation. FIG.
10D illustrates the return operation, where finger element 84 is extended.
Stop member 97 engages the finger element 84 at the other zone limit and
causes the sprinkler to shift to forward operation.
The apparatus of FIGS. 10A-10D has the advantage that it is impossible to
cause operation of the sprinkler in a "forbidden" zone, i.e. the
geometrical complement of the desired zone.
Reference is now made to FIGS. 11A-11D which illustrate another embodiment
of the invention wherein a pair of nearly complete concentric parallel cam
rings are defined on the radially inner facing surfaces of rings 90 and
92. These rings operate to force the stop members 100 and 102 into a
radially inward extended orientation except when full circle mode
operation is indicated by registration of protrusions 94. A side view of
part of the inner surface of rings 90 and 92 is provided in FIG. 12
showing stop members 100 and 102.
It is noted that the general construction of the stop members 100 and 102
is similar to the construction of stop members 97 and 98 described above.
Here, however, there is no need for spring-like biasing of the stop
members into a radially inward extended orientation since the cam rings,
104 and 106, operate to force the stop members radially inwardly except
when the gaps 108 and 110 in the cam rings are arranged in registration or
near registration adjacent the stop members. This occurs only when full
circle operation is indicated. It is noted that each of the stop members
100 and 102 engages the cam ring on the ring 90 or 92 to which it is not
mounted and is also suitably positioned for desired engagement with the
finger element 84.
FIGS. 11A and 11B illustrate the sprinkler arranged for full circle mode
operation. Here the gaps 108 and 110 are in registration, permitting the
stop members to assume their retracted orientations, as shown. FIG. 11A
illustrates forward motion, with finger element 84 in its retracted
orientation and limiting element 80 out of engagement with engagement
portion 88 of the hammer deflector. Forward motion may continue without
any interference from the stop members as long as full circle mode
operation is indicated.
FIG. 11B illustrates return motion wherein the finger element 84 is
extended.
FIGS. 11C and 11D illustrate zone mode operation of the sprinkler. FIG. 11C
shows return motion wherein the finger element 84 is extended and stop
member 102 engages the finger element at the extreme of the intended
angular range of sprinkler coverage, for shifting the sprinkler to forward
motion. FIG. 11D shows forward motion of the sprinkler, with finger
element 84 in a retracted orientation and limiting element 80 in a
disengaged orientation with respect to engagement portion 88 of the hammer
deflector. Finger element 84 engages stop member 100 which is in its
extended radially inward orientation for shifting to return motion at the
second extreme of the intended angular range of sprinkler coverage.
Reference is now made to FIG. 14 which is a pictorial schematic
illustration of an alternative embodiment of finger element 110 which may
be used in place of finger element 84, described hereinabove. Finger
element 110 defines a pivot poriton 112, an arm portion 114, a common
vertical portion 116, which lies parallel to axis 12 (FIG. 1) and first
and second engagement finger tips 118 and 120. Finger tips 118 and 120
preferably lie in different horizontal and vertical planes as defined with
respect to axis 12.
The construction of finger element 110 has the particular advantage that
there is no maximum limit on the size of the zone selected, i.e. the
maximum may exceed 360 degrees and further that the maximum and minimum
angular segment definitions are independent of the particular geometry of
the stop members 122 and 124 associated therewith.
In the embodiment of FIG. 14 and also in other embodiments of the
invention, constructions may be provided wherein the stop members move
into and out of engagement with the finger element other than radially
inward and outward. For example, the movement may be parallel to the axis
of rotation of the stem of the sprinkler.
Reference is now made to FIG. 15 which is a pictorial illustration of
protrusions 130 which may be used in place of protrusions 94 described
hereinabove. Protrusions 130 are provided with arrows 132, typically
integrally formed therewith, for indicated the zone of sprinkler coverage.
The arrows may bear a written or pictorial legend thereon indicating
wetness or the like.
The arrow portions bearing the written or pictorial legend may be arranged
as illustrated to overlap when the protrusions are brought together thus
covering one or more of the legends as appropriate during full circle
operation.
Reference is now made to FIGS. 16, 17 and 18 which are respective side,
horizontal section and vertical section illustrations of a sprinkler
constructed in accordance with an alternative embodiment of the present
invention. The general construction of the embodiment of FIGS. 16-18 is
similar to that of the sprinkler described hereinabove. Therefore specific
mention will be made only of particular constructional and operational
differences between the embodiments.
It is noted that here a unitary element 138 defines the base and the cam
defining the sprinkler pattern configuration. A removable plug 140 is
provided in registration with the central axis 12 of the sprinkler and
below the water inlet of the sprinkler stem. When plug 140 is in position,
the water inlet to the base is from the side as in the embodiment
described hereinabove. When plug 140 is removed, a water inlet may be
threadably or otherwise connected directly onto the bottom of the stem,
thus providing the possibility of direct verticle pipe mounting of the
sprinkler or of mounting the sprinkler onto a spike support having its own
side water input and which provides a combination water connection and
support coupling.
The embodiment of FIGS. 16-18 also comprises a shield 146 which is disposed
directly in front of the zone setting protrusions for preventing
engagement of the protrusion for conversion of the sprinkler from full
circle to zone operation when the protrusions 94 lie directly in line with
the sprinkler nozzle. This prevents operation of the sprinkler in an
undesired zone of operation.
It will be appreciated by persons skilled in the art that the present
invention is not limited to what has been particularly shown and described
hereinabove. Rather the scope of the present invention is defined only by
the claims which follow:
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