Generator for cyclically moving jets

A generator for cyclically moving jets comprises a housing including a chamber having a circular track therein, a body disposed in the chamber and rollable along the circular track, a hollow revolvable axle coupled to the body and extending to outside of the chamber and rotatably born in and sealed to the housing, a nozzle attached to the axle outside of the chamber for issuing at least one jet misalignedly in relation to the axis of rotation of the axle, and a fluid flow supply leading to an upstream region of the chamber. In operation, fluid flows past the body, through the hollow revolvable axle and issues from the nozzle as a jet. The body rolls along the circular track as a consequence of fluid-dynamic forces acting on the body. A fountain employs the generator for dynamic display of the cyclically moving jets issuing therefrom.

This invention relates to apparatus and method for generating cyclically 
moving fluid jets for disbursing from the generator and, in particular, to 
generating such jets by the action of fluid-dynamic forces upon a body 
suspended in fluid flow and cyclically movable as a consequence thereof, 
whereby at least a component of the body motion is utilized to 
continuously redirect at least one jet formed of the fluid flow into a 
cyclically moving path. Further more particularly, one of the tasks of the 
present invention is the generation of cyclically moving discrete jets in 
three-dimensional patterns that move at adequately slow speeds to be 
visually discernible and to thusly provide attractive dynamic visual 
effects that are, for instance, appropriately usable in decorative display 
fountains. 
A variety of devices is known for issuing cyclically moving or repetitively 
pulsating fluid jets wherein the impetus for the dynamic action of the 
jets is derived from fluid-dynamic effects of the fluid flow itself. For 
instance, a class of such devices known as "Fluidic Oscillators" relies on 
such effects solely without employing moving parts. Typical examples of 
such devices are disclosed in U.S. Pat. No. 4,184,636. Numerous other 
devices rely upon moving parts (moved by the flow itself) for redirection 
and/or interruption of fluid flow therein and for forming of moving flow 
output patterns or jets. For example, turbine-like mechanisms (using 
fluid-driven rotors) are employed in some personal shower heads to provide 
massage effects by virtue of issuance of repetitively interrupted or 
redirected flow patterns. For instance, U.S. Pat. No. 3,473,736 discloses 
a pulsating device for water outlet fixtures whose operation relies upon a 
turbine rotor driving a radially ported valve. 
Disclosed in U.S. Pat. No. 4,026,470 is a shower flow modulator for 
providing a massaging effect that relies upon a hydrodynamically-shaped 
member which is attracted into and then repulsed from a stream of water 
passing through the modulator, whereby the direction of travel and 
intensity of the stream is varied. The hydrodynamically-shaped member is 
suspended in a ball-socket configuration to permit it to move in 
oscillating manner. 
An example of a device that includes in a flow tube a ball that is 
prevented from moving axially of the tube by a stop, but that is of such a 
size relative to the tube that flow past the ball causes rotational and 
lateral movement thereof, is disclosed in U.S. Pat. No. 3,885,434. 
Although intended for flowmetering purposes (by detection of the ball 
motion), clearly this device will cyclically modulate local flow in 
different localities just downstream from the ball. However, the disclosed 
device cannot practically produce discrete jets that move in 
three-dimensional patterns at visually discernible speeds; the latter 
being indicated, for instance, by the relatively high ball-rotation 
frequency disclosed (column 3 line 19-21). 
Whereas prior-art devices for generating cyclically moving jets or flow 
patterns are generally not unsatisfactory for particular intended 
purposes, on the most part they are incapable of providing jets in 
discrete form that move regularly and uninterruptedly cyclically in 
three-dimensional patterns. In this respect, "three-dimensional patterns" 
are to be understood as including jet paths moving through three spatial 
dimensions (or jet directions moving through two dimensions), as opposed 
to "two-dimensional patterns" wherein jet motion is substantially within a 
single plane and producing a fan-like pattern. Further, prior-art devices 
are generally impractical in providing, without too much mechanical 
complexity or excessive size, adequately low speeds of jet motion for the 
jet to be visually discernible and to thusly provide attractive dynamic 
visual effects. 
For instance, whereas the embodiment disclosed in FIGS. 42 and 43 of the 
above referred to U.S. Pat. No. 4,184,636 shows a device for producing 
three-dimensional output jet patterns, it has been less than satisfactory 
to obtain therefrom visually discernible discrete jets unless rather large 
(and thereby low-frequency) oscillator structures are utilized. 
Similarly, in respect to devices employing turbine-like mechanisms, the 
difficulty of obtaining satisfactory low rotor speeds has precluded 
practical use for producing adequately low-speed jet motions, unless 
high-speed rotor motion is employed and geared down or otherwise reduced 
with attending complexity of mechanism. 
The flow modulator disclosed in the above referred to U.S. Pat. No. 
4,026,470, being intended for producing massaging effects, appears clearly 
incapable of producing discrete jets of visually attractive appearance at 
adequately low speeds of jet motion. 
In view of the foregoing, it is a feature of the present invention to 
provide apparatus and method for generating cyclically moving fluid jets 
by the action of fluid-dynamic forces upon a body suspended in fluid flow 
and cyclically movable as a consequence thereof, whereby at least a 
component of the body motion is utilized to continuously redirect at least 
one jet formed of the fluid flow into a cyclically moving path. An 
important feature of an embodiment of the present invention is the 
generation of cyclically moving discrete jets in three-dimensional 
patterns that move at adequately slow speeds to be visually discernible 
and to thusly provide attractive dynamic visual effects that are usable in 
decorative display fountains. 
SUMMARY 
In accordance with principles of the present invention, a generator is 
provided for generating cyclically moving fluid jets by the action of 
fluid-dynamic forces upon a body suspended in fluid flow and cyclically 
movable as a consequence thereof, whereby at least a component of the body 
motion is utilized to continuously redirect at least one fluid jet formed 
of the fluid flow into a cyclically moving path. The generator comprises a 
housing including a chamber having an internal circular track. The body 
includes an external circular periphery and is suspended within the 
chamber so that it is rollable with its external circular periphery along 
the internal circular track of the chamber. Fluid flow is supplied to the 
chamber into an upstream region with respect to the circular track and the 
fluid flow is conducted out of the chamber from a downstream region with 
respect to the circular track. 
The body is connected to an axle that extends to the outside of the chamber 
so that at least a component of the body motion is transferred to the 
axle. The axle is borne in bearing means in the housing and is sealed to 
the housing. A fluid conduit leads through the axle from the downstream 
region of the chamber to a nozzle that is attached to the portion of the 
axle that is disposed outside of the chamber. The nozzle forms and directs 
at least one fluid jet in a direction that does not coincide with the 
direction of the axis of rotation of the axle. 
In one embodiment of the invention, the body is connected to the axle via a 
rotational coupling permitting angular misalignments therebetween (for 
instance a universal joint coupling). Radial and axial bearing means are 
provided in this embodiment. A spherical bearing to support the axle in 
the housing against radial and axial loads and permitting simultaneously 
angular orientation changes of the axle about a center of the spherical 
bearing is provided in another embodiment instead of the rotational 
coupling between the body and the axle. 
In operation, fluid-dynamic forces acting on the body, by virtue of fluid 
in the chamber flowing past the body, cause the body to move and roll with 
its external circular periphery along the internal circular track of the 
chamber. The rolling motion of the body has a component of rotation. At 
least this component is transferred via the axle to the nozzle and thereby 
to the jet issuing therefrom. As the jet is directed differently than the 
direction of the axis of rotation of the axle (and therewith the nozzle), 
the initial jet direction describes a path along a conical surface or 
along a circular plane; the latter, if the jet is directed perpendicularly 
to the axis of rotation of the axle, whether or not the jet direction 
intersects this axis. Of course, the initial jet direction can be parallel 
to and spaced from the axis of rotation of the axle. In the latter case, 
the initial jet direction describes a path along a cylindrical surface 
(tending to become a conical surface). 
A fountain employs the generator for dynamic display of the cyclically 
moving jets issuing therefrom. The displayed jets can be stroboscopically 
illuminated to enhance the visual attraction of the fountain.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIG. 1 of the drawings, a generator 10 comprises a housing 
12 including a chamber 14 having an internal circular path or track 16, a 
body 18 movably disposed in the chamber and including a circular external 
periphery 20, mechanical transferring means 22 for transferring at least a 
component of the motion of body 18 to the outside of chamber 14, fluid 
supply means 24 for supplying fluid flow to an upstream region 26 of 
chamber 14, fluid conducting means 28 for conducting fluid flow from a 
downstream region 30 to outside of chamber 14, and nozzle means 32 for 
issuing at least one fluid jet into ambient. 
Chamber 14 (in housing 12) has a chamber axis 29 and a substantially 
axisymmetrical shape (about axis 29) and generally extends longitudinally 
between an inlet end 33 and an outlet end 33'. In operation, supply fluid 
flows in chamber 14 substantially unidirectionally and irreversibly in an 
overall direction along the chamber's longitudinal extent from fluid 
supply means 24 at inlet end 33 into upstream region 26, past body 18 into 
downstream region 30 and to outlet end 33', and farther via fluid 
conducting means 28 through outlet end 33'. 
Chamber 14 has a bore 34 to the outside thereof through housing 12 and, 
disposed in bore 34, bearing means 36 that include a thrust bearing 38 and 
a radial bearing 40. Mechanical transferring means 22 include a revolvable 
axle having a first length portion 42 and a second length portion 44 that 
are mutually interconnected by connecting means 46. First length portion 
42 is attached to body 18. Connecting means 46 includes a universal joint 
coupling that permits relative angular misalignment between coupled 
members while transferring rotation therebetween. Second length portion 44 
is born in bearing means 36 and includes fluid conducting means 28 in form 
of an axial conduit 48 that communicates with downstream region 30 via one 
or more radial holes 50. Nozzle means 32 are attached to the right-hand 
end of the second length portion 44 and receive fluid flow from axial 
conduit 48 for issuing from the nozzle means. Second length portion 44 is 
sealed with respect to housing 12 by sealing means included in bearing 40, 
as the here employed bearing is a plain bearing, although other bearing 
types can be used in conjunction with, for example, an `O` ring as the 
sealing means. 
Fluid supply means 24 include a cavity in the upstream region 26 and a 
supply conduit thereto, here shown as a lateral bore. It should be 
understood that supply means 24 can be in any other suitable configuration 
that provides fluid flow to upstream region 26. For instance, the bore of 
region 26 can extend to the left to the outside of housing 12 and can have 
fluid-conducting piping attached and sealed to this bore for supplying 
fluid from a source not shown here. 
Nozzle means 32 include at least one nozzle 52 for issuing a jet therefrom. 
Nozzle 52 has a directional outlet axis 54 for issuing a jet therealong. 
Second length portion 44 of the revolvable axle of mechanical transferring 
means 22 has a rotational axis 56. The orientation of directional outlet 
axis 54 differs from (or is intentionally misaligned with respect to) the 
orientation of rotational axis 56. These two axes can, but need not, 
mutually intersect. 
The circular external periphery 20 has a centerline 58 defined 
perpendicularly thereto. This centerline also defines a body axis 59 
coaxially therewith. First length portion 42 of the revolvable axle of 
mechanical transferring means has a rotational axis 60 that is coaxial 
with centerline 58. In operation of the generator, rotational axes 56 and 
60 are not coaxial, but mutually intersect at the pivot point of the 
universal joint coupling of connecting means 46. 
In the region of the circular external periphery 20, chamber 14 has 
internal circular track 16. Body 18 is rollable with its circular external 
periphery 20 along internal circular track 16 by virtue of fluid-dynamic 
forces exerted onto the body 18 while fluid flows past the body from 
upstream region 26 to downstream region 30. 
The region of chamber 14 at and in the vicinity of the internal circular 
track 16 is defined as a fluid-dynamically active region 62. The internal 
wall portion of the chamber in the fluid-dynamically active region is 
substantially cylindrical, although conical shapes can be employed. As 
substantially cylindrical or slightly conical wall shapes in the active 
region are preferred for practical reasons, the depiction in FIG. 1 is 
intended to be viewed to also represent conical wall shapes in active 
region 62. 
Body 18 includes an external peripheral surface 64 (that includes circular 
external periphery 20) that is axisymmetric in relation to body axis 59. 
External peripheral surface 64 is a surface of revolution about body axis 
59, the surface having a substantially smoothly arcuate and externally 
convex generatrix (with respect to body axis 59). As shown, body 18 is 
barrel-shaped. A spherical body shape can be alternately employed under 
certain operating conditions. As body 18 is rollable within chamber 14, 
the largest diameter of the body must be smaller than the inside diameter 
of the chamber 14 in the vicinity of the body. More particularly also, the 
diameter of circular external periphery 20 is smaller than the diameter of 
internal circular track 16. 
Referring now to FIG. 2, the shown fragmental cross-section is in the plane 
of the internal circular track 16 and only approximately in the plane of 
the circular external periphery 20. FIG. 2 shows body 18 in chamber 14 of 
housing 12 at an instant in time during operation of the generator 
according to principles of the invention; i.e. while body 18 rolls with 
its external circular periphery 20 along internal circular track 16. 
Further shown in FIG. 2 is a rotation arrow 70 indicating rotation of body 
18 about body axis 59 as a consequence of the rolling motion of body 18 
along track 16. It will be appreciated that body axis 59 describes a 
circle while the body rolls along track 16. This circle is indicated here 
as rolling motion circle 72. It will be further appreciated that the 
direction of rolling motion is opposite to the direction of the rotation 
of body 18. A diametral gap 74 between body 18 and the chamber wall of 
housing 14 provides the flow area for fluid flow to pass. 
It should be understood that the rotational speeds of the body rotation and 
of the rolling motion differ significantly from one another. In absence of 
any slippage between body and housing, the body rotation speed is related 
to the rolling motion speed in the ratio of the diametral gap 74 (at the 
internal circular track 16) divided by the diameter of the circular 
external periphery 20 of body 18. 
Referring now to FIG. 3, there is shown a typical moving jet pattern as 
seen at an instant in time and provided during operation by a generator of 
the invention, for instance the embodiment shown in FIG. 1. The generator 
10 is oriented substantially vertically having three mutually diverging 
jets directed generally upwardly. The generator can be visualized from 
this depiction in one of its advantageous uses as a dynamic display 
fountain. The three jets revolve at a relatively slow speed that 
facilitates viewing and discerning individual jets as they rise, gradually 
break up into drops, and eventually fall under the influence of gravity. 
For example, a speed of jet pattern rotation up to about 150 RPM has been 
found suitable for such display fountain uses. It will be appreciated that 
any number of jets can be used. Even a single jet produces an attractive 
pattern. In this respect, for instance, the depiction of FIG. 3 can be 
visualized as representing a triple (photographic) exposure of a single 
revolving jet taken at equal intervals. 
FIG. 3 is further also representative of a dynamic display fountain 
including generator 10 to produce at least one revolving jet, when the 
rotational speed of the jet is significantly higher so that an individual 
discrete jet cannot be easily (or not at all) visually discerned by the 
unaided eye, but when the produced revolving jet pattern is 
stroboscopically illuminated while being viewed. For instance, 
illumination at a stroboscopic light flash repetition frequency of three 
times the rotation frequency of a single jet issuing from generator 10 can 
provide a view as depicted here. It will be appreciated that the obtained 
view provides a revolving pattern if the two frequencies are not exactly 
synchronized, whereby the pattern revolves at the difference frequency. 
Referring now to FIG. 4, there is schematically shown a generator 80 that 
is basically similar to generator 10 (of FIG. 1), except that the 
mechanical transferring means, now designated by numeral 82, are comprised 
of a substantially one-piece rigid axle assembly that is attached to body 
18 at one end and that has nozzle means 32 connected thereto at the other 
end externally of chamber 14. The axle assembly revolves about an axis 85 
and, additionally, takes part in the rolling motion of body 18 along 
internal circular track 16. Further, generator 80 differs from generator 
10 in regard to comprising bearing means that include a spherical pivot 
bearing 84. Bearing 84 serves to support the axle in different angular 
orientations in relation to housing 12 while body 18 rolls along internal 
circular track 16 (see also FIG. 2) and while, as a result of the rolling 
action, axis 85 moves along a cone surface having the pivot center of the 
bearing 84 as its apex. Further shown here is an `O` ring 86 that is 
included in the sealing means between housing and the axle of mechanical 
transferring means 82. `O` ring 86 serves to seal the outer portion of the 
spherical member of the spherical bearing 84 to housing 12. Inasmuch as 
the embodiment of FIG. 4 is structurally basically the same as that of 
FIG. 1 in other aspects, reference is hereby made to such other aspects 
described hereinbefore in conjunction with FIGS. 1 and 2. 
Referring now to FIG. 5, there is shown a typical moving jet pattern as 
seen at an instant in time and provided during operation by a generator 80 
(of FIG. 4). FIG. 5 is similar to FIG. 3, except that the depicted jet 
pattern includes further a modulational motion in each jet in form of a 
high-frequency rotation about a centerline of each jet. This modulational 
motion corresponds and is caused by the rolling motion of body 18, as 
described hereinbefore in conjunction with FIG. 2 (in particular also in 
respect to rolling motion circle 72). Generator 80 is again oriented 
substantially vertically having three mutually diverging jets directed 
generally upwardly. The generator can be visualized from this depiction in 
one of its advantageous uses as a dynamic display fountain. The three jets 
revolve at a relatively slow speed that facilitates viewing and discerning 
individual jets as they rise, gradually break up into drops, and 
eventually fall under the influence of gravity. For example, a speed of 
jet pattern rotation up to about 150 RPM has been found suitable for such 
display fountain uses. It will be appreciated that any number of jets can 
be used. Even a single jet produces an attractive pattern. In this 
respect, for instance, the depiction of FIG. 5 can be visualized as 
representing a triple (photographic) exposure of a single revolving jet 
taken at equal intervals. 
FIG. 5 is further also representative of a dynamic display fountain 
including generator 80 to produce at least one revolving jet, when the 
rotational speed of the jet is significantly higher so that an individual 
discrete jet cannot be easily (or not at all) visually discerned by the 
unaided eye, but when the produced revolving jet pattern is 
stroboscopically illuminated while being viewed. For instance, 
illumination at a stroboscopic light flash repetition frequency of three 
times the rotation frequency of a single jet issuing from generator 10 can 
provide a view as depicted here. It will be appreciated that the obtained 
view provides a revolving pattern if the two frequencies are not exactly 
synchronized, whereby the pattern revolves at the difference frequency. 
In operation of a generator of the invention (either generator 10 of FIG. 1 
or generator 80 of FIG. 4), fluid flow past body 18 in chamber 14 
generates fluid-dynamic forces upon the body that cause the body to 
initially move approximately radially toward the chamber wall and to, 
thereafter, roll with its external circular periphery 20 along internal 
circular track 16 of chamber 14. The high-speed rolling motion of body 18 
causes a low-speed rotation of the body about an axis 59 that is 
perpendicular to the center of external circular periphery 20. The rolling 
motion further causes a precession-like motion of axis 59 in relation to 
chamber 14 and housing 12, as the body is pivotably supported in a 
location along its axis 59. The pivotable support is in connecting means 
46 (universal joint coupling) in the embodiment of FIG. 1 and it is in the 
spherical pivot bearing 84 in the embodiment of FIG. 4. 
The fluid flow supplied to the generator, subsequent to passing by body 18, 
is conducted out of the chamber through a conduit disposed within the 
portion of the axle of mechanical transferring means (22 in FIG. 1; 82 in 
FIG. 4) that extends to the outside of the chamber 14. This fluid flow is 
fed through nozzle means 32 and issues to ambient through a nozzle outlet 
along directional outlet axis 54. As at least the rotational component of 
the motion of body 18 about its body axis is transferred to nozzle means 
32, the jet issuing therefrom effects a revolving jet pattern. This 
pattern is formed as a result of the jet describing a helical-conical 
spiral, at least initially upon issuing from the nozzle. This pattern 
moves regularly and cyclically. 
While the invention has been particularly shown and described with 
reference to preferred embodiments thereof, it will be understood by those 
skilled in the art that various changes and modifications in form and 
details may be made therein without departing from the spirit and scope of 
the invention.