Note: Descriptions are shown in the official language in which they were submitted.
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IMPROVEMENTS IN OR IN RELATION TO POOL CLEANERS
FIELD OF THE INVENTION
THIS INVENTION relates to improvements in or in relation to pool
cleaners and particularly to pool cleaners of the self propelled type.
BACKGROUND TO THE INVENTION
Self propelled pool cleaners have various mechanisms used for
propulsion, some involving pulsating water flow, two examples are described
below.
Some pool cleaners that employ self propulsion mechanisms have a
i 0 valve arrangement that intermittently opens and closes and this provides
the
propulsive force that propels the pool cleaner across the pool bottom and up
and around wall surfaces. One arrangement employs a flexible diaphragm.
The diaphragm has a flow through passage with a normally narrow throat. The
throat is biased to a normally narrow position by the form of its construction
but
can be pulled open when a negative pressure is applied thus opening the
passage. The throat is located inside a chamber and due to the construction of
the chamber as pump pressure is applied to the cleaner outlet, pressure drops
around the diaphragm and since the throat is flexible and can expand, the
throat widens and in turn produces a pulse of flow. The pulse gives rise to a
corresponding change in pressure as the throat widens, the pressure equalises
which allows the throat to return to normal but as soon as it does the
pressure
drops and the process repeats at a frequency of about 60 cycles per minute.
In another arrangement a hammer mechanism oscillates back and forth
opening and closing the flow and this propels the pool cleaner.
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Cleaners of this type have a generally circular skirt which travels over
the pool bottom and wall surface to clean the surface. The skirts have a
varying configuration from radially pleated to flat skirts. Some skirts
include
projecting fingers, castellated periphery and radial slits. The skirts may
include
circumferentially spaced radially extending slots or grooves, or pleats. The
skirt
remains in close contact with the surface being cleaned as the cleaner moves
with a pulsing action across the pool surface. These cleaners typically
include
the skirt in a horizontal plane, a main body inclined to the vertical at about
45
degrees and a bumper wheel located at the top of the main body which serves
to deflect the top portion of the cleaner and keep the cleaner in operative
alignment when close to walls, steps and other obstacles around the pool.
It is usual for the pool cleaners of this type to have the ability to climb
pool walls and the like and in a climbing action, once the skirt comes away
from the wall, the pool cleaner usually free falls back to the bottom of the
pool
to re-commence its cleaning action. In some cleaners, it is usual to employ a
float and opposed counter weight so that when the cleaner is in free fall
towards the bottom, the float serves to right the cleaner so that it lands
"cat
like" with the skirt facing downwards and engaging the bottom of the pool.
US Patent 4,742,593 describes a pool cleaner of the type employing a
flexible diaphragm as described above.
WO 2004/007872 describes a pool cleaner with round skirt and a float
carried at an aft portion for acting in conjunction with a weight in allowing
the
cleaner to fall to an upright position when dropping from the side wall of a
swimming pool. The float is a sphere or ball and is in a fixed central
position.
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The float and weight are just above and just below a horizontal line extending
front to back. The float is on the end of an arm toward the rear of the
cleaner
and the weight toward the front located at the end of a projecting spur. This
arrangement means that as the front is being pulled down by the weight the
rear is being pulled up by the float so as the cleaner falls the front of the
skirt is
the first part to touch the pool bottom in the usual way but the spur weight
is
prone to damage and wear. US Patent 6,119,293 describes a similar cleaner in
as far as the relative positions of the float and weight, in this case the
float is at
the end of a central stem fitted at the very rear and bottom of the cleaner
body
and behind the water inlet in the centre of the skirt. The stem is either
flexible
or swivels about on a ball in a D-shaped cut out within side lobes. A weight
is
located in front of the cleaner and the effect of the float and weight is to
steer
the cleaner away from the water surface. In this patent there are various
options and extra additions including extra weights around the base that are
said to further assist in the cleaner adopting the desired attitude. In
addition the
cleaner in US 6,119,293 is basically a float on a stick attached to a ball
joint
which is non-adjustable. The float and stick arrangement will wear the body at
the ball joint and the whole cleaner must be replaced. The single arm applies
torque at only one point which is not near its centre of mass.
WO 2006/109118 describes a pool cleaner with a float suspended on a
pair of slotted arms which move freely on bilateral pins. The slots are much
larger than the pins so that the float arms not only move in and out but there
is
enough play between the slots and the pins that the float has limited sideways
movement. In Figure 3 of this specification the postion of the float arms are
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illustrated for the situation where the cleaner is travelling along a wall.
Specifically, since the pivot pins are fixed on the sides of the cleaner the
upper
arm nearest the wall shortens relative to its pin and the lower arm furtherest
from the wall lengthens relative to its pin effectively jamming the float in
an
inclined attitude with two points of contact for each arm, one with the pin
and
the other with the body of the cleaner. Thus the turning moment applied is
proportional to the length of the lower arm and its contact point with the
body.In
the description this is postion is said to aid the cleaner climbing the wall.
There
is no mention of the float serving any other purpose.
WO 2008/037024 uses a pivoting float to keep the cleaner correctly
oriented. The float is a cylindrical float having its long axis extending
across the
cleaner and being supported at each end by arms which pivot about a pivot
axis parallel to the cylinder axis. A counterweight is opposite the float and
the
float is said to stabilise the cleaner body as it sinks and keep it upright.
The
pivot axis of the float is directly over the weight so that the float can
swing front
to back across the weight. A cleaner marketed under the brand name Kreepy
Krauly is similar to this having a float assembly where two floats are joined
by
U-shaped joiners and the floats can pivot fore and aft and the float and
counterweight are mounted on a rotating collar so that the float and counter
weight rotate in concert with the collar.
US Patent 7,434,285 describes a pool cleaner with a fixed float for
automatic uprighting. The pool cleaner has an opening for flow of water into
the
pool cleaner and the float is located directly and vertically above the
opening.
While these pools cleaners all work well they all operate randomly and
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while it is desirable to clean the pool wall most sediment accumulates on the
pool bottom so the length of time that a cleaner is travelling on the pool
wall
means there is less time spent cleaning the pool bottom.
Therefore it is an object of the present invention to provide a pool
5 cleaner which has a greater residence time on the pool bottom. US Patent
6,119,293 operates similar to the present invention in so far as the float is
able
to move both sideways and fore and aft by reason of the ball joint and
scalloped guide but the geometry of relative positions of the float and weight
and the independent fore and aft pivot and sideways movement embodied in
the present invention provides an improved response time and faster self
righting which makes a pool cleaner with the present improvements more
efficient. In the present invention when the cleaner is oriented on a wall and
climbing the applied torque to force the cleaner back down the wall is
optimised
so that total residence time on the pool bottom is increased.
It is therefore a further object of the present invention to provide a pool
cleaner with fore and aft and sideways float movement that improves applied
torque and therefore response time and overall efficiency.
OUTLINE OF THE INVENTION
In view of the above objects of the pool cleaners actual orientation
during cleaner operation is a significant and controlling consideration in
defining the invention, consequently the following statements describes broad
aspects of the improvements both in terms of structure and orientation during
operation.
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In one aspect there is provided in a self propelled pool cleaner of the
pulsating flow type having a generally flat skirt, a hollow body having a
lower aft
end and an upper fore end, an inlet near the aft end of the body, the inlet
being
bounded by the skirt, an outlet near the fore end of the body and connectable
to a hose, the body housing a valve and flow passage communicating between
the inlet and outlet, the body having an upper side and a lower side and
having
its aft end coupled to the skirt and the body being inclined to the skirt, a
pivoting float assembly, the float assembly having a float suspended from the
upper side of the body, a float mounting mechanism positioned on the upper
side of the body, the mounting mechanism permitting fore and aft movement of
the float assembly as well as side to side movement of the float assembly, a
counterweight opposite the float an improvement comprising:
the mounting mechanism has a transversely extending guideway
constraining the side to side movement of the float along the guideway
independently of the fore and aft float movement;
the float being moveable relative to the counterweight;
bilateral float stops limiting sideways travel of the float;
such that when the skirt is travelling along a pool wall the float travels
toward its zenith and an uppermost stop is engaged before the float reaches
its
zenith, the float applying an upward moment to the body whereafter the float
moves aft turning the pool cleaner down the wall.
In another aspect there is provided in a self propelled pool cleaner of the
pulsating flow type having a generally flat skirt, a hollow body having a
lower aft
end and an upper fore end, an inlet near the aft end of the body, the inlet
being
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bounded by the skirt, an outlet near the fore end of the body and connectable
to a hose, the body housing a valve and flow passage communicating between
the inlet and outlet, the body having an upper side and a lower side and
having
its aft end coupled to the skirt and the body being inclined to the skirt, a
pivoting float assembly, the float assembly having a float suspended from the
upper side of the body, a float mounting mechanism positioned on the upper
side of the body, the mounting mechanism permitting fore and aft movement of
the float assembly as well as side to side movement of the float assembly, a
counterweight mounted opposite the float mounting mechanism an
improvement comprising:
the hollow body has a central axis;
the counterweight extends axially and is confined to a region adjacent
the inlet and just below the central axis;
the mounting mechanism is located adjacent the inlet and being directly
above the counterweight in opposed relation;
the float being moveable relative to the counterweight;
the mounting mechanism having bilateral float stops limiting sideways
travel of the float such that when the skirt is travelling along a pool wall
the float
travels toward its zenith and the uppermost stop is engaged before the float
reaches its zenith, as the cleaner begins to travel horizontally the body is
urged
to rotate about its central axis by the counterweight applying a downward
rotational force on one side of the central axis while the float applies an
upward
rotational force on the opposite side of the central axis, the upward
rotational
force being applied to the body in the vicinity of the counterweight.
Preferably,
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the counterweight is formed integrally with the body and is located just in
front
of the inlet.
In one preferred embodiment there is provided a self propelled pool
cleaner of the pulsating flow type having a generally flat skirt, a hollow
body
having a lower aft end and an upper fore end, an inlet near the aft end of the
body and connectable to a hose, the inlet being bounded by the skirt, an
outlet
near the fore end of the body, the body housing a valve and flow passage
communicating between the inlet and outlet, the body having an upper side
and a lower side and having its aft end coupled to the skirt and the body
being
inclined to the skirt, a pivoting float assembly, the float assembly having a
float
suspended from the upper side of the body, a float mounting mechanism
positioned on the upper side of the body, the mounting mechanism permitting
fore and aft pivoting movement of the float assembly as well as side to side
movement of the float assembly relative to an opposing counterweight, the
mounting mechanism having a transversely extending fore and aft float
movement pivot axis, the fore and aft float movement pivot axis being
moveable side to side as the float travels side to side, bilateral float stops
to
limit sideways travel of the float such that when the skirt is travelling
along a
pool wall the float travels toward its zenith and the uppermost stop is
engaged
before the float reaches its zenith, the float applying an upward moment to
the
body to relieve the skirt wherein the float pivots aft driving the pool
cleaner
down the wall. In this embodiment the counterweight and the float mounting
mechanism are located just in front of the inlet.
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Preferably, the float is mounted with a first pivot mounting and the first
pivot mounting is itself mounted with a guide moveable in a guide-way.
Typically, the guide-way is an arcuate guide-way and preferably the guide-way
is a circumferentially extending guide-way extending around an upper most
part of the body opposite the counter weight. The guide-way may be circular
and be connected to a non-circular main body.
Preferably, the float is a pivoting float and the mounting mechanism has
a transversely extending fore and aft float movement pivot axis, the fore and
aft
float movement pivot axis being moveable side to side as the float travels
side
to side, the float being suspended on a transverse pivot pin having a length
about as wide as the body adjacent to the pivot pin.
Preferably, the pool cleaner has a generally horizontal skirt and a body
inclined to the vertical coupled to the skirt, a deflector wheel in a plane
substantially at right angles to the body and having a lower edge of the
deflector wheel adjacent the peripheral edge of the skirt, the spacing between
the peripheral edge of the skirt adjacent to the lower edge of the deflector
wheel being so chosen and arranged to prevent pool surfaces entering the
space between the lower edge of the deflector wheel and the nearest adjacent
edge of the skirt and impinging against the body of the pool cleaner.
Preferably, the pool cleaner has an inner tube with an inner tube support
for a pool cleaner employing inner and outer tubes held within a two part main
outer body, the inner tube having a diaphragm mounted in line with the inner
tube forming an inner tube and diaphragm assembly, the outer tube forming a
pressure chamber around the diaphragm, the inner tube support comprising a
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plug in diaphragm holder surrounding the inner tube and holding the inner tube
in axial alignment, the tube support having flow though passage means
communicating with the pressure chamber, the support comprising a wall
projecting across from an inner wall of the main body to the inner tube to
hold
5 the inner tube in fixed spaced relation to the inner wall of the main body,
the
flow though passage means comprises circumferentially spaced openings, the
wall projecting across has an inner ring which fits into a circular channel in
a
collar in the diaphragm and the body is separable into two axially extending
housing parts joined together at or adjacent the diaphragm holder.
10 Preferably, the float mounting mechanism is axially adjustable. Typically,
the float mounting mechanism includes a C-shaped clip on guideway and the
body has axially spaced latches so that the body can clip into the float
mounting mechanism with a hand insertable snap action.
Typically, the housing parts are oval in cross-section where they join so
that they separate when twisted.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the present improvements may be more readily understood
and be put into practical effect, reference will now be made to the
accompanying drawings and wherein:-
Figures 1 and 2 illustrate embodiments wherein longer and shorter body
portions are utilised, where in Figure 1 a bumper strap is used and Figure 2 a
shorter body is used to eliminate the need for a bumper strap;
Figure 3 illustrates use of a two direction pivoting float;
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Figure 4 is a cross sectional view of a typical pool cleaner according to
the one aspect of the invention;
Figure 5 is the section of Figure 4 with the skirt and bumper wheel
omitted;
Figure 6 is an embodiment showing a longitudinal cross section
illustrating the inner tube support and the diaphragm in position;
Figure 7 is a section through 7-7 of Figure 6;
Figures 8 and 9 illustrate the multi-directional pivoting action of the float;
Figure 10 illustrates a preferred guide and guide-way for the float;
Figure 11 illustrates the guide-way in greater detail;
Figure 12 is a drawing illustrating a typical trajectory of a pool cleaner
according to the invention compared with a similar pool cleaner but without
the
specific float and counterweight relationship peculiar to the present
invention;
Figures 13 to 15 illustrate how the body separates into two parts; and
Figure 16A - 16F illustrate how a diaphragm is replaced.
METHOD OF PERFORMANCE
Referring to the drawings and initially to Figures 1 and 2 there is
illustrated respective pool cleaners 10 and 11 with the pool cleaner 10 having
a
body portion 12 and the pool cleaner 11 having a body portion 13 which is as
shown shorter in length than the body portion 12 of the pool cleaner 10. As
illustrated, the two pool cleaners shown are navigating across a series of
steps
14 and 15 respectively. The body portion 12 of the pool cleaner 10 is prone to
engage a step as shown and the arrows 16 and 17 show the effect of the
oscillating action of an internal diaphragm or hammer arrangement usual in
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these types of cleaners. The pool cleaner 10 has become stuck on the step
and will simply vibrate up and down and remain in that position by reason of
the step engaging against the body and the bumper wheel 18 being caught on
the horizontal section 19 of the step above. In order to overcome this
problem,
shown in phantom is the use of a bumper strap 20. Bumper straps 20 is of the
type illustrated in Figure 1 and are commonly used in order to prevent the
problem illustrated in Figure 1.
Figure 2 illustrates an alternative to this whereby the shorter body and
the relative disposition of the extremity of the bumper wheel 21 and the
peripheral edge 22 of the skirt 23 is such that it is much shorter than the
height
24 of a step and in this case about 180mm. Thus it is not possible for the
step
corner 25 to pass between the bumper wheel 21 and the skirt periphery 22 at
their nearest points.
In both cases the cleaners are equipped with a float 26 which is located
opposite a counter weight 27 with the float 26 being mounted on a pivot arm 28
so that the float may pivot in the direction of arrow 29 about a pivot pin 30.
The
counterweight is close in to the central axis and formed integral with the
body
so that there is little if any prospect of wear. The float is suspended a
relatively
long distance from the central axis so that it provides a rotary moment to the
body while the counterweight also provides a rotary movement and both these
are in the same vicinity so that rotary torque is optimised for better
steering
without twisting as in some of the prior art models.
The pivot pin 30 is adapted to travel in a guide-way about an arc having
a pivot axis co-axial or thereabouts with the central axis 31 of the body 12
and
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body 13 respectively. The guide way can be made integral with the body or
may be a detachable and adjustable part as will be described below. The
function and operation of this shall become clearer in the description to
follow.
The cleaner 11 is shown in perspective view in Figure 3, it being appreciated
that the only substantial difference between the cleaner 11 and the cleaner 10
as illustrated in Figure 1 is the length of the body with the internal
structure and
other parts of the cleaner being the same and these will be discussed in the
description which follows. One important consequence of the shortening of the
body is that the float is prevented from laying flat against the body by the
bumper wheel. This means that when the cleaner is travelling up a wall the
float rides against the bumper wheel so as the cleaner begins to move to the
horizontal the float is already substantially in position to turn the pool
cleaner
down. Again this further increases response time which increases residence
time on the pool bottom.
As can be seen in Figure 3, the arm 28 is fitted to a clip on guide-way 32
which has tangs which clip into slots 33 on opposite sides of the body 13. The
operation and pivoting action of the guide-way and float relative to the body
13
will be described in greater detail in relation to Figures 8 to 11.
In Figure 3, the outer body 13 has a flange 34 which takes a removable
foot 35 to adapt the flange to hold the skirt 23.
Referring now to Figures 4 and 5, Figures 4 and 5 illustrate the
assembly of the body 13 with the interior part whereby a diaphragm of known
construction 36 is located inside the body 13. The diaphragm is in
communication with an inner tube 37 connected to the upper end 38 of the
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diaphragm so arranged that parallel flow paths are created from the inlet 39
between the inner tube 37 and the outer tube 40 to a hose, not shown,
connected to the outer tube 40. The outer tube has a tapered end 41. A
pressure differential causes the diaphragm 36 to expand and contract between
the position shown and the expanded position shown in phantom at 42 thus
causing an intermittent pulsing action which propels the pool cleaner along
the
surface of the pool being cleaned. Pool cleaners of this type are self
propelled
along the bottom of the pool and up the side walls of the pool until such time
as
the suction holding the skirt in place against the surface weakens or becomes
dislodged by obstacles such as pool lights so that it is released from the
surface and the pool cleaner falls by gravity back to the bottom of the pool.
Cleaners of this type have been prone to fall to the bottom in a non-
operative position and it has been known to utilise floats but these floats
have
not utilised the dual directional pivoting action illustrated which dual
directional
pivoting action is in the vicinity of the counter weight 27 and is guided in
its
sideways movement. This speeds up the righting of the pool cleaner so that it
rights itself quicker than is the case in the prior art. In the illustrated
embodiment, the pivot arms 28 have ends located in a circular guide-way 43
and the body 13 in this embodiment is circular as well as is the guide-way 43
and the guide 44.
Further features illustrated in Figures 4 and 5 include the section of the
foot 35, the foot 35 being of known configuration and having a channel 45
adapted to receive the skirt within the channel 45 in operative position as
illustrated in Figure 4.
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In the illustrated embodiment, the outer tube 40 is secured to the outer
body 13 using a hand nut 46 which screws on to a threaded clamping
arrangement at 47. The outer tube includes a flange 48 which abuts against a
washer 49 and the outer tube 40 includes an extension 50 extending into the
5 body 13 so that the outer tube 40 may rotate within the body 13. The
extension 50 is selected in length to minimise rocking action of the tube 40
and
thereby inhibit wear in the region of its connection within the body 13 since
the
outer tube permits rotation of the hose relative to the cleaner and is to
minimise
hose twisting.
10 The bumper wheel 21 is held in position by reason of the inner surface
51 of the hand nut 46 butting against the bumper wheel at 52 and the shoulder
53 on the other side of the hand wheel of the body 13.
Referring now to Figures 6 and 7, the connection of the diaphragm 36 in
place is illustrated and the inner tube 37 is fitted in the flexible end 54.
The
15 outer end 55 has flexible ribs 56, 57, 58 and 59 which clip in to
corresponding
channels as illustrated. The inner end 54 has a channel 60 which by reason of
the flexibility of the rubber material from which the diaphragm is made the
diaphragm locates with the channel 60 in the position illustrated relative to
a
circular retainer ring 61. The retainer ring or support which can more clearly
be
seen in Figure 7 has flow through apertures 62, 63, 64 and 65 for water flow
between the inner and outer tubes.
Referring now to Figures 8 to 10 an alternative arrangement mounting of
the float 26 is illustrated when compared to the arrangement of Figures 5 and
6. The arrangement of Figures 8 to 11 corresponds to the arrangement
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illustrated in Figures 1 to 3 whereby the body 13 has slots 33 diametrically
opposed on the body 13 and these receive tangs 66 and 67 which depend
from a circular body 68. The body 68 carries a circular guide-way 69 with a
guide 70 travelling between opposite ends of the guide-way.
It will be appreciated that the body 13 need not be of circular cross
section in this arrangement since the guide-way clips to it and is independent
of it as is the guide. Thus from the perspective of aesthetics an oval body
may
be used without affecting the operation of the pivoting action of the float as
illustrated. An oval body also facilitates construction of the body from two
parts
that may be easily separated by hand for replacement of the diaphragm. The
float 26 is connected to the guide by two pivot arms 71 and 72 which have
openings at their ends so that they slide into position and are retained in
place
by snap in retainers 73 and 74 (not shown in Figures 10 and 11). The guide 70
has a circular shoulder 75 and at opposite ends of the guide has projections
76
and 77 such that the rail 78 of the guide-way is retained between the surface
75 and the inner surfaces 78 and 79 of the projections 76 and 77 with the rail
against the surface 80. A corresponding structure is on the opposite side of
the guide and this retains the rail 81 so that the guide slides around a
circular
path defined by the rails 78 and 81. The guide 70 includes internal bores 82
and 83 at opposite ends and these are blind bores with an internal rib 84 so
that stubs projecting from retainers 73 and 74 may snap fit into the bores 82
and 83 to retain the arms 71 and 72 in place and permit the pivoting action of
the float 26 as illustrated in Figure 8 and Figure 9.
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Referring to Figure 12 there is illustrated a typical comparative trajectory
of the pool cleaner of the present invention showing the trajectory of a pool
cleaner with a lower response time in broken line. Both pool cleaners enter
the
turn at the same trajectory but a pool cleaner according to the present
invention turns sooner.
In pool cleaners of the present kind equipped with a diaphragm, the
diaphragm goes through a very large number of repetitions of expansions and
contractions so its life is limited and it can split and must be replaced. The
present pool cleaner is made to facilitate ease of diaphragm replacement and
this is depicted in drawings Figures 13-15 and 16A-16F.
Referring to Figures 13-15 a pool cleaner 11 with it outer tube, nut and
bumper wheel removed exposing the thread 85 and the top end of inner tube
86. The body 87 in this case is made from an upper part 88 and a lower part
89. The lower part 89 has a circular recess 90. An annular spacer 91 fits into
the recess 90. A flexible diaphragm 92 has an upper collar 93 which includes
an outer circular groove 94. The annular spacer 91 has an inner ring 95 which
fits snugly into the groove 94 so that the annular spacer may operate as a
diaphragm holder, the holder being a plug in part that fits into the cleaner
body.
The inner tube 86 then fits inside the collar and is retained in the collar.
The
body is non-circular in cross section in the region of the spacer and is held
together by axial protrusions on the inside of the part 88 locating in shallow
axial recesses on the overlapping outside of the part 89. In order to separate
the parts it is simply back and further twisting action while pulling and they
easily separate as shown in Figures 13 and 15.
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Once the parts 88 and 89 have been separated the part 88 may be
removed as shown in Figure 16A. The tube 86 is then removed as shown in
Figure 16B exposing the collar 93 of the damaged diaphragm. The damaged
diaphragm may be manually manipulated and pulled out through the skirt end
95 and then with the inner tube reversed and fed through the inner ring 95 of
the spacer 91 exposing the top end 96 of the inner tube 86 as shown in Figure
16C. The collar of the diaphragm is then squeezed as shown in Figure 16D
and fitted into the end 96 so that the tube 86 may be used to drawer the
diaphragm into the part 89 and thereby manually manipulate the collar of the
diaphragm into the position illustrated in Figure 14. This involves the top
end of
the tube 86 being removed after drawing the diaphragm though and this is
shown at Figure 16E. The tube 86 is then reversed and its opposite grooved
end 97 is then inserted back into the collar being the reverse of Figure 16B
and
then the reverse of Figure 16A sees the two parts put back together. The
bumper wheel and outer tube are then put back in place and the nut is screwed
onto thread 85.
Whilst the above has been given by way of illustrative example, many
variations and modifications thereto will be apparent to those skilled in the
art
without depending from the broad ambit and scope of the invention as set out
in the appended claims. For example the counterweight weighs approximately
375 gms and the float is mounted at the end of arms measuring 13cm and the
float is oval in cross-section having a length of 9 cm and elliptical axes of
8cm
and 4cm. The float is filled a material having a Specific Gravity less than 1
so
that even if the float becomes cracked the cleaner will still work properly.
Of
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course all these dimensions could vary considerably while still being within
the
ambit of the invention.
