Water cooler abstract
An automatic valve assembly for a water cooler having a reservoir
of the type that has its upper end generally sealed to the atmosphere
by a water bottle adapter that receives and supports an inverted
water bottle. The valve assembly comprises a ventilation passageway
that permits air to enter the reservoir, and an actuator arm hingedly
mounted within the interior of the water cooler. The actuator arm
is operable to move between an open and a closed position in response
to changing water levels within the reservoir. When in its open
position the actuator arm allows the unrestricted passage of air
into the reservoir through the ventilation passageway. When in its
closed position the actuator arm restricts the flow of air and fluids
through the ventilation passageway.
Water cooler claims
We claim:
1. An automatic valve assembly for a water cooler having a reservoir
of the type that has its upper end generally sealed to the atmosphere
by a water bottle adapter that receives and supports an inverted
water bottle, the valve assembly comprising: (i) a ventilation passageway
providing a means for air to enter said reservoir; and, (ii) an
actuator arm hingedly mounted within the interior of said water
cooler and operable to move between an open and a closed position
in response to changing water levels within said reservoir, when
in said open position said actuator arm allowing the unrestricted
passage of air into said reservoir through said ventilation passageway
and when in said closed position said actuator arm restricting the
flow of air and fluids through said ventilation passageway, said
actuator arm including a sealing element disposed in said reservoir
and moveable in response to movement of said actuator arm, when
said actuator arm is in said open position said sealing element
permitting air to flow through said ventilation passageway into
said reservoir and when said actuator arm is in said closed position
said sealing element preventing the passage of air and fluids through
said ventilation passageway, said sealing element comprised of a
resilient compressible material that is driven into contact with
said ventilation passageway upon the movement of said actuator arm
with a rise in the water level within said reservoir beyond a predetermined
level such that a further rise in the water level within said reservoir
causes said sealing element to be compressed about said ventilation
passageway to restrict the passage of air or fluids therethrough.
2. The device as claimed in claim 1 wherein said actuator arm includes
at least one float such that as the water level within said reservoir
rises said float causes said actuator arm to rotate about said hinge
and move from said open to said closed position.
3. The device as claimed in claim 1 wherein said actuator arm is
comprised of a sealed and generally hollow body that generally floats
upon the surface of water stored in said reservoir.
4. The device as claimed in claim 1 wherein said actuator arm is
an enclosed polygon formed from a generally hollow, plastic, molded
body.
5. The device as claimed in claim 2 wherein said actuator arm comprises
a generally circular floating ring.
6. The device as claimed in claim 1 wherein said ventilation passageway
is a conduit extending through said water adapter having a lower
end terminating within said reservoir.
7. The device as claimed in claim 6 wherein said lower end of said
conduit is tapered having a lower terminal surface of reduced cross-sectional
area, said sealing element contacting said lower terminal surface
upon said actuator arm moving to said closed position.
8. The device as claimed in claim 7 wherein said lower end of said
conduit is comprised of a resilient compressible material that is
at least partially compressed upon said actuator arm moving to said
closed position.
9. The device as claimed in claim 6 wherein said lower end of said
conduit is comprised of a resilient compressible material that is
at least partially compressed upon said actuator arm moving to said
closed position.
10. The device as claimed in claim 1 wherein said ventilation passageway
includes a filter to help prevent the ingress of dirt and debris
into said reservoir as air is drawn through said ventilation passageway.
11. The device as claimed in claim 1 wherein said ventilation passageway
is a conduit extending through said water adapter and having a lower
end terminating within said reservoir.
12. The device as claimed in claim 11 wherein said lower end of
said conduit is comprised of a resilient compressible material,
said resilient compressible material at least partially compressed
by said actuator arm upon said actuator arm moving to said closed
position.
13. The device as claimed in claim 11 wherein said lower end of
said conduit is tapered and has a lower terminal surface of reduced
cross-sectional area.
14. The device as claimed in claim 13 wherein said lower end of
said conduit is comprised of a resilient compressible material,
said resilient compressible material at least partially compressed
by said actuator arm upon said actuator arm moving to said closed
position.
15. An automatic valve assembly for a water cooler reservoir, the
valve assembly comprising: (i) a ventilation passageway providing
a means for air to enter said reservoir, said ventilation passageway
comprising a conduit having a lower end terminating within said
reservoir; (ii) an actuator arm hingedly mounted within said reservoir,
said actuator arm comprising a float that is operable to move between
an open and a closed position in response to changing water levels
within said reservoir, said lower end of said conduit comprised
of a resilient compressible material, said resilient compressible
material at least partially compressed by said actuator arm upon
said actuator arm moving to said closed position; and, (iii) a sealing
element positioned upon said actuator arm adjacent said lower end
of said conduit such that when said actuator arm is in said open
position said sealing element is withdrawn from said lower end of
said conduit, when said actuator arm is in said closed position
said sealing element is driven into contact with said lower end
of said conduit and restricts the flow of air and fluids through
said ventilation passageway.
16. The device as claimed in claim 15 wherein said lower end of
said conduit is tapered and has a lower terminal surface of reduced
cross-sectional area.
17. An automatic valve assembly for a water cooler having a reservoir
of the type that has its upper end generally sealed to the atmosphere
by a water bottle adapter that receives and supports an inverted
water bottle, the valve assembly comprising: (i) an actuator arm
positioned within said reservoir and hingedly mounted to said water
bottle adapter, said actuator arm comprising a float that is operable
to move between an open and a closed position in response to changing
water levels within said reservoir; and, (ii) a ventilation passageway
providing a means for air to enter said reservoir, said ventilation
passageway comprising a conduit having a lower end terminating within
said reservoir, said lower end of said conduit comprised of a resilient
compressible material that is at least partially compressed by said
actuator arm upon said actuator arm moving to said closed position
to thereby restrict the flow of air and fluids through said ventilation
passageway.
18. The device as claimed in claim 17 wherein said lower end of
said conduit is tapered and has a lower terminal surface of reduced
cross-sectional area.
Water cooler description
FIELD OF THE INVENTION
This invention relates to an automatic valve assembly for a water
cooler reservoir, and in particular a valve assembly to assist in
the interruption of the flow of water from an inverted water bottle
mounted upon a sealed water cooler reservoir.
BACKGROUND OF THE INVENTION
The basic design of a water cooler is well known. With an increasing
level of concern over the safety of much of the world's drinking
water, the utilization of bottled water as a source of water for
drinking, cooking and other applications has increased tremendously.
Along with the increase in the use of bottled water there has been
a significant advance in the design of water coolers and their component
parts. For example, whereas initially such appliances were merely
capable of dispensing water from an inverted bottle, today they
commonly provide water that is chilled, heated and/or dispensed
at room temperature. Further, others have developed a variety of
different water bottle caps and mounting adapters to support bottles
upon coolers that help to prevent spillage of water when inverting
a filled bottle and placing it upon the bottle support structure.
Still others have created structures that assist in sealing the
cooler in order to limit or prevent the ingress of dirt and other
debris that may contaminate water stored in the reservoir (see,
for example, U.S. Pat. Nos. 6167921 5526961 and 5646127
as representative examples of such devices).
While much has been accomplished in the design of water coolers
to help prevent the contamination of water stored in the reservoir
and to assist consumers in placing an inverted bottle onto the top
of the cooler, little effort has been directed at a recurring problem
that occurs when a bottle develops a small hairline crack or fracture
in its outer surface. For obvious cost and weight benefits, most
water bottles are formed from a relatively thin plastic material.
When in use on a water cooler, the pressure differentials that the
bottles are subjected to typically result in a flexing of the walls
of the bottle, inwardly and outwardly as water is delivered to the
reservoir and air is returned to the bottle. This flexing process
can serve as a means by which small cracks or fractures in the bottle
may develop over time. Even where a bottle shows no sign of leakage,
when inverted and placed upon a cooler at some point during its
use the bottle may develop a small crack or hole. The increased
use of bottled water tends to exacerbate the problem since water
bottles are continuously re-filled and re-used to the point that
eventually they are prone to developing cracks in their side walls.
In the situation where an inverted filled bottle has or develops
a small fracture or crack in its surface, the fracture presents
an avenue by which air may enter the bottle, which in turn may cause
the contents of the bottle to overflow the reservoir and spill onto
the floor or surrounding surface area. In some instances the volume
of water that can overflow the reservoir may be in the nature of
a few gallons, which can cause substantial damage to flooring, furniture,
and other surrounding items.
In an effort to combat this problem, others have incorporated within
the reservoirs of water coolers small floats or bobbers that are
meant to help reduce the flow of air into the reservoir. By reducing
or slowing the flow of air into the otherwise sealed reservoir there
is presented a means to at least partially control the flow of water
from the bottle. Unfortunately, such existing devices are to a large
extent ineffective in situations where a bottle develops a relatively
small fracture that permits its contents to slowly be drained into
the reservoir. That is, such existing devices tend to be somewhat
effective in situations where there has been a significant breach
in the wall of a water bottle but generally do not have the ability
to positively and completely seal the reservoir air passageway where
water slowly drains from a bottle that has developed a fine crack
or fracture. Such prior devices also tend to be prone to becoming
misaligned and may have a diminished effectiveness in situations
where the water cooler is not vertically oriented.
SUMMARY OF THE INVENTION
The invention therefore provides an automatic valve assembly for
a water cooler reservoir that assists in controlling the downward
flow of water from an inverted water bottle into the reservoir through
the provision of an enhanced and improved mechanism to control the
flow of air into the reservoir, and to thus help prevent the flow
of water from the bottle when the reservoir is filled to its capacity.
Accordingly, in one of its aspects the invention provides an automatic
valve assembly for a water cooler having a reservoir of the type
that has its upper end generally sealed to the atmosphere by a water
bottle adapter that receives and supports an inverted water bottle,
the valve assembly comprising a ventilation passageway providing
a means for air to enter said reservoir; and, an actuator arm hingedly
mounted within the interior of said water cooler and operable to
move between an open and a closed position in response to changing
water levels within said reservoir, when in said open position said
actuator arm allowing the unrestricted passage of air into said
reservoir through said ventilation passageway and when in said closed
position said actuator arm restricting the flow of air and fluids
through said ventilation passageway.
In a further aspect the invention provides an automatic valve assembly
for a water cooler reservoir, the valve assembly comprising a ventilation
passageway providing a means for air to enter said reservoir, said
ventilation passageway comprising a conduit having a lower end terminating
within said reservoir; an actuator arm hingedly mounted within said
reservoir, said actuator arm comprising a float that is operable
to move between an open and a closed position in response to changing
water levels within said reservoir; and, a sealing element positioned
upon said actuator arm adjacent said lower end of said conduit such
that when said actuator arm is in said open position said sealing
element is withdrawn from said lower end of said conduit, when said
actuator arm is in said closed position said sealing element is
driven into contact with said lower end of said conduit and restricts
the flow of air and fluids through said ventilation passageway.
In another aspect the invention provides an automatic valve assembly
for a water cooler having a reservoir of the type that has its upper
end generally sealed to the atmosphere by a water bottle adapter
that receives and supports an inverted water bottle, the valve assembly
comprising an actuator arm positioned within said reservoir and
hingedly mounted to said water bottle adapter, said actuator arm
comprising a float that is operable to move between an open and
a closed position in response to changing water levels within said
reservoir; and, a ventilation passageway providing a means for air
to enter said reservoir, said ventilation passageway comprising
a conduit having a lower end terminating within said reservoir,
said lower end of said conduit comprised of a resilient compressible
material that is at least partially compressed by said actuator
arm upon said actuator arm moving to said closed position to thereby
restrict the flow of air and fluids through said ventilation passageway.
Further aspects and advantages of the invention will become apparent
from the following description taken together with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention, and to show
more clearly how it may be carried into effect, reference will now
be made, by way of example, to the accompanying drawings which show
the preferred embodiments of the present invention in which:
FIG. 1 is a side perspective view of a water cooler;
FIG. 2 is a partial vertical sectional view through the water cooler
of FIG. 1 showing an embodiment of the automatic valve assembly
of the present invention in its closed position;
FIG. 3 is a partial vertical sectional view through the water cooler
of FIG. 1 showing an embodiment of the automatic valve assembly
of the present invention in an open position;
FIG. 4 is a side view of a float ring in accordance with one preferred
embodiment of the present invention;
FIG. 5 is a sectional view taken along the line 5--5 of FIG. 4;
FIG. 6 is a sectional view taken along the line 6--6 of FIG. 5;
FIG. 7 is a top plan view of the water bottle adaptor of the water
cooler shown in FIG. 2;
FIG. 8 is a bottom view of the water bottle adapter of the water
cooler shown in FIG. 2;
FIG. 9 is a sectional view taken along the line 9--9 of FIG. 7;
FIG. 10 is a sectional view taken along the line 10--10 of FIG.
7 and depicting an alternate embodiment of the present invention;
and,
FIG. 11 is an enlarged detail view of portion "A" shown
in FIG. 10.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention may be embodied in a number of different
forms. However, the specification and drawings that follow describe
and disclose only some of the specific forms of the invention and
are not intended to limit the scope of the invention as defined
in the claims that follow herein.
In the attached drawings, FIGS. 1 2 and 3 generally show the primary
components of a water cooler 1 of the type designed for receiving
an inverted water bottle 2 (shown in ghost outline in FIGS. 2 and
3). Since many of the features of a standard water cooler are not
directly relevant to the present invention, they have not been shown
in the attached Figures, or in other instances may be shown but
are not specifically discussed.
In FIG. 1 water cooler 1 is shown as comprised generally of an
outer cabinet 50 having a top 60 adapted for receiving and supporting
an inverted water bottle 2. Positioned on the front surface 70 of
cabinet 50 there will typically be one or more valves or spigots
80 that are activated to dispense water from the cooler. The number
of valves that are utilized is dependent upon whether the cooler
has the capacity to dispense chilled and/or heated water in addition
to room temperature water. A drip tray 90 is often positioned below
valve 80 in order to collect and drips or spillage that may occur
when the valve is activated.
Referring to FIGS. 2 and 3 water cooler 1 also includes a reservoir
4 a water bottle adapter 5 a bottle cap engaging probe or pin
6 and an upper cover ring 7. The overall structure and construction
of these primary components of cooler 1 are not unlike those that
have been in use for a considerable length of time. Reservoir 4
is constructed with a generally open upper end that is generally
sealed to the atmosphere by water adapter 5. In the specific embodiment
shown, water bottle adapter 5 includes a circumferential lip seal
8 that bears against the interior surface of the reservoir housing
when the adapter is received into the open upper end of the reservoir.
Access to the reservoir is then restricted to the flow of water
through bottle cap engaging pin 6 and through an air or ventilation
passageway, both of which are discussed below in greater detail.
As is standard in many water coolers, water bottle adapter 5 has
a conical or funnel-like shape and is designed to receive and support
bottle 2 in an inverted orientation such that water within the bottle
may be gravity fed into reservoir 4. Typically water bottles for
use in association with coolers utilize a cap 9 that encloses their
open ends and that provides a means to allow water to be dispensed
from the bottle when inverted, while at the same time helping to
prevent the spillage of water when inverting a water bottle and
placing it into adapter 5. These caps also present a mechanism for
re-sealing the bottle upon its removal from the cooler. That function
is accomplished through the utilization of a particular cap design
that incorporates an internal valve that co-ordinates with bottle
cap engaging pin or probe 6. As the inverted bottle is lowered into
water bottle adapter 5 pin 6 is received through bottle cap 9
effectively opening the valve within the cap and allowing water
to pass through pin 6 and into reservoir 4. Although a further understanding
of the structure and function of bottle cap 9 and bottle cap engaging
pin 6 is unnecessary for a complete understanding of the present
invention, reference maybe made to Canadian patent 2093006 dated
Dec. 8 1998 as a resource document that more fully describes the
operation of the bottle cap and pin mechanisms.
Traditionally, water coolers of the type generally described above
have permitted water to flow downwardly from an inverted bottle
placed upon the cooler until the level of water in the reservoir
reached a height at which air ceased to flow or gurgle back into
the bottle. At that point the flow of water from the bottle into
the reservoir was effectively stopped. As water was drawn from the
cooler through valve 80 the level of water within the reservoir
dropped and the flow of water from the bottle into the reservoir
was re-established. To permit the flow of air into the reservoir
(and ultimately back into the water bottle) the water bottle adapters
of prior existing coolers commonly contained one or more air passageways
extending therethrough. Such passageways presented a mechanism to
allow for air to flow into and out of the reservoir the reservoir
as the level of water went up or down.
Such systems relied upon the sides of the water bottle to remain
in tact so that air could only be drawn into the bottle through
pin 6. In this manner, as water was drawn from the bottle and the
level of water within the reservoir rose to a sufficient degree
the vacuum condition created within the interior of the bottle effectively
offset the hydraulic head of the water and prevented further downward
flow into the reservoir. Unfortunately, as discussed above, bottle
fatigue sometimes results in small holes or cracks developing in
the sides of the bottle, permitting atmospheric air to be drawn
directly into the bottle. When that occurs the equilibrium condition
that prevents further downward flow of water no longer exists allowing
the contents of the bottle to drain completely into the reservoir,
often causing the reservoir to overflow.
To prevent the above situation, in a preferred embodiment the present
invention comprises an automatic valve assembly 10 that includes
a ventilation passageway 11 and an actuator arm 12. Actuator arm
12 includes at least one float 13 and is hingedly mounted within
reservoir 4 such that the raising or lowering of the water level
within the reservoir causes the actuator arm to pivot and rotate
in a generally vertical plane relative to the reservoir. Ventilation
passageway 11 is comprised of a conduit that extends through water
bottle adapter 5 and has a lower end 14 terminating within the reservoir
to provide a means for air to flow into or out of the reservoir
as required. To prevent dust, dirt and other debris from being drawn
into the reservoir, in a preferred embodiment of the invention the
upper end 15 of ventilation passageway 11 is fitted with a filter
cap that contains a replaceable or washable filter material.
In the particular embodiment of the invention shown in FIGS. 2
and 3 ventilation passageway 11 and actuator arm 12 are positioned
so that the pivotal movement of actuator arm 12 is in a generally
upward direction such that when raised, the actuator arm will eventually
come into contact with lower end 14 of ventilation passageway 11.
When the arm contacts lower end 14 it will effectively block the
flow of air and fluids into and out of reservoir 4. Since actuator
arm 12 preferably includes at least one float 13 it will be appreciated
that the upward rotational movement of the arm will be caused by
a rising water level within the reservoir. That is, as water passes
from bottle 2 through pin 6 and into reservoir 4 the rising water
level will cause actuator arm 12 to rotate upwardly and seal against
lower end 14 of ventilation passageway 11. At that point there can
be no movement of air or fluids through the ventilation passageway.
It will thus be appreciated that through the combination of the
sealing of ventilation passageway 11 and through sealing the upper
end of the reservoir with the use of lip seal 8 there will be no
way for make-up air to be drawn into the reservoir preventing any
further flow of water from bottle 2. The flow of water will effectively
be stopped, even in instances where the sidewalls of water bottle
2 develop small holes or fractures that allow air to be drawn into
the bottle. Under such circumstance, water cannot continue to flow
into the reservoir as there will be no place for it to accumulate
or escape. Valve assembly 10 will thereby effectively prevent a
damaged bottle from allowing its contents to overflow the reservoir.
In the particular embodiment of the invention shown in the attached
drawings, actuator arm 12 is comprised of a sealed and generally
hollow body 17 that floats upon the surface of the water stored
in the reservoir. For ease of manufacturing, and in an attempt to
maximize the buoyancy of actuator arm 12 the arm may be formed
in the shape of an enclosed polygon which, as indicated in FIGS.
4 5 and 6 may have the general shape of a circular floating ring.
It is also expected that most instances arm 12 would be moulded
from a plastic material.
Referring to FIGS. 4 5 and 6 in the embodiment of the invention
that is shown actuator arm 12 is of a generally circular configuration
having a first portion 18 that is hingedly secured within reservoir
4 and a second portion 19 that effectively serves to function as
float 13. First portion 18 comprises an outwardly extending and
generally rectangular support flange 20. Lying in a plane that is
generally perpendicular to the axis of arm 12 and passing through
support member 20 is a pin or axle 21 about which actuator arm
12 pivots. Axle 21 engages a pair of lugs 22 extending downwardly
from the lower surface of water bottle adapter 5 adjacent to ventilation
passageway 11 (see FIGS. 2 8 and 9). Axle 21 and lugs 22 thus effectively
secure actuator arm 12 to water bottle adapter 5 and present a hinged
connection about which the actuator arm may be caused to rotate
with fluctuations in the water level within the reservoir. While
in this embodiment actuator arm 12 is hingedly secured to water
bottle adapter 5 those skilled in the art will appreciate that
the actuator arm could equally be hingedly secured to the inner
wall of the reservoir.
By means of the described manner of securing actuator arm 12 to
water cooler 1 it will be understood that a rise in the water level
within the reservoir will cause the arm to pivot upwardly about
axle 21 until such time as the upper surface 23 of arm 12 comes
into contact with lower end 14 of ventilation passageway 11. At
the initial point of contact a preliminary seal will be formed between
arm 12 and ventilation passageway 11. In the event that the seal
does not fully and completely prevent the movement of air through
the passageway into reservoir 4 the water level within the reservoir
will continue to rise causing actuator arm 12 to rotate further
in a generally upward direction. This further upward movement of
actuator arm 12 will cause the application of a torsional force
upon axle 21 and a compressive force between surface 23 and lower
end 14 of ventilation passageway 11. The shape and configuration
of actuator arm 12 and the fact much of the arm is offset from
its point of contact with ventilation passageway 11 results in
hollow body 17 effectively becoming a moment arm. The amount of
force that can be applied between upper surface 23 and lower end
14 of ventilation passageway 11 will therefore be enhanced due to
the application of force (through the buoyancy of arm 12) at a distance
from passageway 11 and from axle 21 about which arm 12 pivots.
To help ensure a high integrity seal between surface 23 of actuator
arm 12 and lower end 14 of ventilation passageway 11 both the lower
end of the passageway and at least the portion of upper surface
23 that bears against lower end 14 may be formed or machined such
that they have a flat and relatively smooth surface. In this manner
when the two surfaces meet they will effectively block the flow
of air or fluids through the passageway. As a means to increase
the seal between ventilation passageway 11 and actuator arm 12
the lower end 14 of the ventilation passageway may also be tapered
to reduce its cross-sectional area. This will have the effect of
concentrating the force applied between the actuator arm and lower
end 14 over a smaller area and enhance the seal therebetween.
In an alternate embodiment the portion of upper surface 23 of actuator
arm 12 that contacts lower end 14 of ventilation passageway 11 may
have applied thereto a resilient compressible material 24 that acts
as a sealing element and that is driven into contact with lower
end 14 as arm 12 is rotated in a generally upward direction. The
compressibility of material 24 will effectively cause it to deform
about lower end 14 with a rise in the level of water within the
reservoir, and increase the integrity of the seal. In a further
alternate embodiment (see FIGS. 10 and 11) the lower end 14 of ventilation
passageway 11 may have applied thereto a resilient compressible
material 25 against which upper surface 23 of arm 12 is driven as
the arm pivots in an upward direction. Compressible material 25
will effectively function in a similar manner as described above
with respect to material 24. If desired valve assembly 10 may include
both a resilient compressible material adhered to upper surface
23 of actuator arm 12 and a resilient compressible material placed
about end 14 of ventilation passageway 11.
Through an understanding of the above described invention it will
be appreciated and understood that automatic valve assembly 10 presents
a number of very significant advantages over prior existing water
cooler structures. First and foremost, valve assembly 10 provides
a mechanism to positively control the flow of water from an inverted
water bottle into a water cooler reservoir, and in particular to
prevent the unintentional overflowing of the reservoir in instances
where the bottle has developed a crack or hole through its exterior
surface. Secondly, the structure of valve assembly 10 presents a
mechanism by which a positive seal of the air passageway into the
reservoir can be achieved, and a structure that increases the integrity
of that seal as the water level in the reservoir rises. Thirdly,
the hinged connection between the actuator arm of valve assembly
10 and the internal structural components of the water cooler ensures
an accurate and proper positioning and placement of the sealing
mechanism relative to the ventilation passageway. In this manner
positioning the water cooler on a non-horizontal surface such that
it is not perfectly upright will have no appreciable effect on the
operation of the valve assembly. In addition, the valve assembly
is not subject to becoming misaligned through normal movement of
the water cooler during shipping and handling. Finally, the described
structure of automatic valve assembly 10 presents an economical
means of sealing the passage of air and fluids through the ventilation
passageway when the reservoir is filled to a pre-determined level.
It is to be understood that what has been described are the preferred
embodiments of the invention and that it may be possible to make
variations to these embodiments while staying within the broad scope
of the invention. Some of these variations have been discussed while
others will be readily apparent to those skilled in the art. |