Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND TO THE INVENTION
This invention relates to an hydraulic m~hine. In one application, the
invention relates to a cleaner for cleaning a submerged surface, such as
the submerged portion of a ~wi~ g pool.
Numerous ~Willllllillg pool cleaners have been proposed, which fall into
two main categories. The first category includes pool cleaners which use
an oscill~ting valve element such as a "hammer" valve or a flexible
diaphragm which alternately constricts and relaxes, to interrupt a flow
of liquid through the pool cleaner repetitively, thus developing forces
which propel the pool cleaner in one direction or another. The second
category of pool cleaners includes those which employ a turbine or the
like which is operated by a flow of water through the pool cleaner, the
turbine in turn driving feet, wheels, tracks or another drive mech~ni~m.
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Generally speaking, although pool cleaners in the first
category are mechanically simple, they tend to impose a
greater amount of stress on the pool filtration unit and
pump due to the repetitive shock waves generated by
their action. Pool cleaners of the second category do
not produce such shock waves, but tend to be more
complicated mechanically than those in the first
category.
SUMMARY OF THE lNvL.lION
A first aspect of the invention provides an hydraulic
machine comprising:
a) a body having a liquid inlet and a liquid outlet
and a conduit extending between the inlet and the
outlet, and
b) a drive element supported in or adjacent to the
conduit, with a clearance between the drive element
and the interior of the conduit, in a manner
permitting variable eccentric location and rotation
of the drive element relative to the conduit,
the conduit being connectable in a liquid flow path so
that liquid passing through the conduit past the drive
element, when the drive element is positioned
eccentrically relative to the conduit, applies
differential forces to the drive element resulting in
rotation of the drive element relative to the inlet.
The liquid outlet is adapted for connection to a suction
source which draws liquid through the inlet, past the
drive element and out of the outlet.
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Preferably, the liquid outlet is provided with a swivel
connector for connecting it to a hose extending to the
suction source.
The drive element may be a ball, cylinder or other
suitably shaped body. In the preferred versions of the
invention, the drive element is a spherical or pear-
shaped ball, and the drive element and conduit have a
circular cross-section. Typically, the drive element is
smaller in diameter than the conduit and is disposed at
least partially within the conduit. Alternatively, the
drive element is larger in diameter than the conduit and
is disposed adjacent the conduit.
In one form of the hydraulic machine, which operates as
a cleaner for submerged surfaces, at least a portion of
the drive element extends beyond the conduit so as to
engage the submerged surface fictionally and so as to
drive the body over the submerged surface as the drive
element rotates. In this case, the cleaner comprises a
support structure extending transversely from the body
which in use engages the submerged surface and prevents
edges of the liquid inlet from dragging over the
submerged surface as the body moves over that surface.
The support structure may be of frustoconical shape and
the periphery of the support structure may carry a ring
which is rotatable relative to the support structure.
Typically, the ring is supported relative to the support
structure by rotatable wheels carried by the periphery
of the support structure.
In some cases, an annular support ring may surround the
body and be connected to the body by a spoked hub.
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In another form of the invention, the drive element acts as a prime
mover and is connected via tr~n.cmiccion means to a secondary drive
element which in use engages a submerged surface and drives the
cleaner over the submerged surface when the drive element, acting as
a prime mover, rotates.
A second aspect of the invention provides a method of driving a
submerged surface cleaner over a submerged surface which is to be
cleaned, the method comprising the steps of disposing a drive element
with clearance in or adjacent a conduit in a manner to allow the drive
element to rotate relative to the conduit and to assume positions which
are eccentric relative to the conduit, connecting the conduit in a liquid
flow path so that liquid flowing through the conduit flows past the drive
element and applies differential forces to the drive element, when the
drive element is positioned eccentrically relative to the conduit, which
results in rotation of the drive element relative to the conduit, and using
the rotation of the drive element to move the cleaner over the
submerged surface.
BRIEF DESCRIPTION OF THE DRAVVINGS
The invention will now be described in more detail, by way of example
only, with reference to the accompanying drawings in which:
Figure 1 is a pictorial view of a cleaner for cleaning a
submerged surface according to the invention;
Figure 2 is a partial sectional view of the cleaner of Figure
l; .
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Figure 3 is a pictorial view of the cleaner of Figure 1 fitted
with a flexible cowl;
Figure 4 is a partial sectional view of an alternative
embodiment of the cleaner;
Figure 5 is a partial sectional view of a further embodiment
of the cleaner;
Figure 6 is a pictorial view of a further embodiment of the
invention;
Figure 7 is a cross-sectional view of the embodiment of
Figure 6; and
Figure 8 is an underplan view of the embodiment of Figures
6 and 7.
DESCRIPIION OF EMBODIMENTS
The pool cleaner illustrated in Figures 1 and 2 comprises a body 10
which is round cylindrical at a first end which defines an inlet 12 having
a circular cross-section. The body narrows towards an outlet 14 defining
a socket 16 in which a ball 18 (see Figure 2) is receivable. The ball 18
has a bore 20 formed therein and has a spigot 22 on one side which
engages a flexible hose 24. Thus, the ball 18 and the socket 16 define
a flexible joint which allows liquid to be sucked through the inlet 12 of
the body, through the conduit defined by the hollow interior of the body,
and out of the outlet 14 into the hose 24. The hose is connected, in a
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conventional manner, to a pool filtration system in use.
Supported within the body 10 is a drive element in the
for~m of a resilient ball 26. The ball 26 is made, for
example, of a dense, resilient foam plastics material
having a rough surface. The ball 26 is fixed to a shaft
28 which has an enlarged head 30 and is held captive by
a plate 32 having a hole therein through which the head
30 cannot pass. However, the shaft 28 and thus the ball
26 can rotate freely about the axis of the shaft 28.
The plate 32 is secured to the legs of a U-shaped
bracket 34 which is supported loosely by a transverse
rod 36 fixed at each end to the sides of the body 10.
Thus, it will be apparent that the ball 26 is not only
rotatable freely about the axis of the shaft 28, but can
also move transversely in the inlet, as indicated by the
dotted lines in Figure 2, thus varying the clearance
between the ball 26 and the inner edges of the inlet.
A support structure in the form of a support ring 38
with an inner hub 40 and radial spokes 42 is received in
a circumferential groove 44 formed in the narrow portion
of the body 10, and is freely rotatable relative to the
body. The support ring 38 extends transversely away
from the body sufficiently far so that when both it and
the ball 26 rest against the submerged surface to be
cleaned, the edges of the inlet 12 are clear of the
surface, preventing dragging.
As shown in Figure 1, a float 46 and a weight 48 are
attached to the flexible hose 24. The relative
positions of the weight and the float can be adjusted to
vary the behaviour of the cleaner in use.
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In operation, water is drawn into the inlet 12 of the
cleaner, past the ball 26. Depending on the lateral
orientation of the ball 26 in the inlet, the flow of
water past the surface of the ball causes it to move in
the inlet. The net result is that the ball is caused to
rotate about the axis of the shaft 28, in one direction
or the other. With the ball 26 resting on the submerged
surface to be cleaned, and assuming that the cleaner is
not standing at exactly 90~C to the surface, this
imparts an arcuate motion to the pool cleaner across the
surface. As the cleaner moves, the orientation of the
hose 24 will change, which tends to change the attitude
of the pool cleaner relative to the surface. This causes
the ball 26 to move orbitally within the inlet, i.e. its
eccentricity within the inlet varies. This in turn
changes the forces on the ball and varies the path taken
by the pool cleaner. It will thus be apparent that the
very simple mechanism described can cause substantially
random motion of the pool cleaner over the surface to be
cleaned.
Assuming that the ball 26 is not disposed absolutely
centrally within the inlet 12, liquid flowing past the
ball will have different speed at different points
around the equator of the ball, and will thus exert
unequal forces on different portions of the ball, giving
rise to the motion described above. It is believed that
the rotational movement of the ball in the inlet is
attributable to differential forces acting directly on
the ball that cause it to spin, or to sideways movement
of the ball against the side of the inlet that give rise
to a rotational drive on the ball.
By ballasting the described device appropriately
adequate contact between the driving ball 26 and the
surface to be cleaned can be ensured. The amount of
ballast employed also affects the ability of the cleaner
to climb the walls of a pool in use. The material used
for the driving ball 26 also has an effect on the
behaviour of the cleaner.
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It is not essential that the drive element used by the pool cleaner be a
ball. It is possible that a hemispherical drive element, or a cylindrical
element having a rounded end could be used. Although a smooth drive
element such as the ball 26 illustrated provides sufficient torque to move
the pool cleaner about s~ticf~ctorily~ the drive element can be provided
with flutes or vanes, for example, to increase the torque available.
Instead, a vane could be fitted to the rod 28 to ensure starting of the
rotation in a desired direction. This would preclude the desirable bi-
directional rotation which is achieved with a smooth drive element. In
some applications, however, it may be desirable to predetermine the
direction of rotation of the drive element.
~ncte~(l of the rigid rod 28 which is used to support the ball 26 in the
inlet 12, other support means can be used. For example, a flexible rod
can be fixed to the interior of the body 10 (or even formed integrally
therewith) with the ball being mounted rotatably on the end of the rod.
The material and thickness of the rod can be selected to be sufficiently
"wllipl~y" to provide the desired freedom of movement of the ball within
the inlet, without the complication of the pivot mech~ni.cm illustrated in
Figure 2.
A further variation of the cleaner is illustrated in Figure 4. In this
embodiment, the ball 26 is held captive within the inlet 12 by inwardly
curved fingers 50 at the periphery of the inlet, and a single radially
inwardly extending finger 52 which is formed integrally with the body 10
and which has a rounded tip 54 which engages the ball 26 with mi~i".~
friction. The finger 52 prevents the ball 26 from being sucked into the
interior of the body 10 in use, while the fingers 50 retain the ball 26
within the body 10 when the pool cleaner is picked up.
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In Figure 3, the pool cleaner is shown fitted with a flexible hood or cowl
56 which is fitted to a circumferential groove in the outer surface of the
body 10. The cowl 56 has raised, radially extending ribs 58 on its
underside. In use, the periphery of the cowl 56 rests against the
submerged surface as the pool cleaner moves across the surface, and
accommodates variations in orientation of the cleaner, while m:~int~ining
a relatively large cleaning area. The ribs 58 ensure the passage of liquid
between the cowl and the submerged surface. Instead of a flexible cowl,
a relatively rigid cowl (possibly comprising two or more parts) can be
fitted movably to the cleaner body.
A further variant of the invention is illustrated schematically in Figure
5. The pool cleaner of Figure 5 has a body 60 which has a central
cylindrical conduit 62 with an inlet 64. Within the inlet 64, a ball 66 is
mounted, much as described previously. The ball 66 is fixed to a rod 68,
which is supported by a ball and socket-type joint 70, so that the ball 66
and the rod 68 can rotate. A gear 72 is fixed to the shaft and mates
with a complemental pinion 74 on a second shaft 76. The shaft 76 is
mounted to allow a~ial movement thereof against the urging of a coil
spring 78, which accommodates movement of the gear 72 due to orbital
motion of the ball 66 in the inlet 64. A spur gear 80 on the shaft 76
engages a gear train which drives a shaft 82 having wheels 84 and 86,
which drive the pool cleaner across the submerged surface 88 in use.
In use, the outlet 90 of the conduit 62 is connected to a flexible hose 92
and liquid is drawn under the periphery of the pool cleaner body and
into the inlet in the direction of the arrows. In this embodiment of the
invention, the ball 66 acts as a prime mover and drives the wheels 84
and 86 through a tr~n~mi~ion, rather than acting as a direct drive
element.
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A further and currently preferred embodiment of the
invention is illustrated in Figures 6 to 8. In this
case, the pool cleaner 100 has a body 102 with a spigot
104 at its upper end to which is attached a socket
member 106 (omitted from Figure 7). A hose connection
spigot 108 is coupled to the upper end of the socket
member 106 at a ball and socket type coupling which
permits free swivelling movement of the hose connection
spigot 108.
At its lower end the body 102 terminates in a round
cylindrical inlet 114 in which is located a ball 116.
The ball in this embodiment is of hollow pear shape and
is made in two parts 116A and 116B which are connected
together as indicated at 118. The ball 116 is suspended
in freely rotatable fashion on a rod 120. The upper end
of the rod 120 passes through a tapered bore in a bush
121 and is supported by a transverse rod 122. The upper
end of the rod is held captive by a circlip 124 that
engages the rod 120 above the rod 122. The illustrated
suspension arrangement allows for free rotation of the
ball 116 and for free pivotal movement of the rod 120
relative to the body 102, as indicated in one plane by
the arrow 123.
The ball is made of resilient plastics material,
promoting a good frictional grip of the ball on a
submerged surface. As illustrated in Figure 8, the
lower surface of the ball 116 is formed with a series of
striations 126 which further enhance the grip of the
ball on the submerged surface.
Extending from the lower extremity of the body 102 is a
support structure in the form of a frustoconical cowl
128 terminating at a peripheral, upstanding ridge 130 on
which a series of angularly spaced, grooved wheels 132
are rotatably mounted. The grooves of the wheels
;
B
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132 engage and retain the inwardly directed rib 134 of an ~nn~ r ring
136 which extends about the periphery of the cowl 128. The wheels 132
allow the ring 136 to rotate freely relative to the cowl. Mounted
rotatably to the lower edge of the ring 136 is a series of smaller wheels
138.
The underside of the cowl 128 carries a series of V-shaped ribs 140 that
define radially extending passages 142 leading to the inlet 114.
In Figure 7, the numeral 144 indicates the horizontal bottom of a
swilllll~il~g pool and illustrates the normal orientation of the pool cleaner
100 in use. At this operative orientation, the wheels 138 ride on the
bottom 144. The angle 148 is typically 23,5~. Also, the ribs 140 are
substantially parallel to the bottom 114 when the pool cleaner is in the
operative orientation.
Loose material on the bottom of the pool is sucked into the inlet 114
through the passages 142. Having reached the inlet 114, the material is
then sucked away through the body 102 and flexible hose 150 (Figure 6)
as in previous embodiments.
At the same time, differential forces on the periphery of the ball 116,arising as a result of eccentric location of the ball in the inlet, cause it
to move in the inlet. The friction between the ball and the bottom 114
causes the pool cleaner 100 to move randomly over the bottom as the
orientation of the ball changes in the inlet 114. The ring 136 and wheels
138 pr~vell~ dragging of the pool cleaner as it moves over the bottom
114.
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Of course, the pool cleaner 100 is not limited to movement over the
bottom of the pool. It is equally capable of climbing the submerged walls
of a pool to perform a suction cleaning operation there.
It will also be appreciated that none of the embodiments described
above is limited in operation to the cleaning of submerged Swi~ g
pool surfaces. It is anticipated that the various cleaners could also be
used to perform suction cleaning of submerged surfaces other than those
of swi",."i~-~ pools.
A major advantage of each of the described embodiments, when
compared to known cleaners operating on the interrupted flow principle,
is the fact that suction is conli,luous, so that less wear of the pump can
be expected. When compared to known turbine type cleaners, the
illustrated embodiments have the advantage of simplicity of construction.
In alternative versions of the invention, the submerged cleaner may
operate, not with suction applied by a filtration pump, but with the
pres~ulised return flow of water relu~l~L~g to a ~wil~ g pool after
filtration. In this case, the return flow is connected to the inlet so as to
force the water to flow. Also, it is anticipated that the novel drive
principles of the invention can be used in applications other than
submerged surface cleaning operations. For instance, the rotational drive
produced by the drive element could be used to drive a paddle or the
like to perform a cleaning operation on the surface of a body of liquid.
