Note: Descriptions are shown in the official language in which they were submitted.
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WASHER ASSEMBLY
s Field of the Invention
The present invention relates to a washer assembly particularly, though not
exclusively,
for a domestic tap or faucet.
Background of the Invention
i o Taps or faucets of the type typically available in the USA and Asia
consist of a tap head
threadingly connected to a tap body, the tap body including a water passageway
having a
fluid inlet, a fluid outlet, and a washer seat therebetween. A spindle is
threadingly retained
within the head so that rotation of the spindle in opposite directions moves
it in an axial
direction up and down within the tap body. A washer assembly typically
including a disc
is of resilient material is fastened by a screw to an end of the spindle.
Accordingly, the
washer assembly turns with the spindle. The washer seat is provided as a
separately
machined insert held with a web extending across the inside of the body. The
insert is
substantially cylindrical in form and has, at an upper end, a radially
extending flange
which is used to support the insert within the faucet body. Radially inward of
the flange is
2 o an upwardly extending spigot. The spigot is formed with a smoothly curved
upper surface
against which the washer assembly pushes when closing the faucet.
A fundamental problem with this type of tap is that because the washer
assembly turns
with the spindle it is subject to excessive wear and tear. Consequently
substantially all of
2 5 the torque applied when turning the tap off is transmitted through the
resilient disc onto
the insert. The harder one turns the spindle the greater the compression and
fictional
forces on the washer assembly and disc. If the washer assembly sufl'ers a
catastrophic
failure, eg tears aware from the spindle, the faucet is likely to leak with a
relatively high
flowrate.
Summary of the Invention
It is an object of the present invention to provide an alternate form of
washer assembly.
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According to the present invention there is provided a washer assembly for a
faucet
including at least:
s a resilient sealing member having a cylindrical wall with opposite first and
second axial
ends and a first wall extending in a radially inward direction from said first
axial end,
wherein said first wall and said cylindrical wall form a cavity into which
fluid can enter
from said second axial end during operation of said washer assembly with said
faucet;
and,
i o a housing having a base and a skirt extending axially from said base to
define a seat in
which said resilient sealing member is retained, said skirt extending axially
beyond said
second axial end of said cylindrical wall and terminating in an annular
surface having an
inner diameter dimensioned to be substantially radially coterminous with an
outer
diameter of said second axial end when said resilient sealing member is
retained in said
is seat.
Preferably said seat has an interior surface of a shape complimentary to an
outside surface
of said resilient sealing member with an outer circumferential surface of said
cylindrical
wall abutting said interior surface of said seat.
Preferably said resilient sealing member is provided with a lip extending
radially inward
from said second axial end to an aperture through which fluid can enter said
cavity, said
lip creating, together with said cylindrical wall and said first wall, a
rebate in said sealing
member to accommodate axial compression of said cylindrical wall as well as
fluid
2 s pressure acting to urge outward deformation of said lip.
Preferably said base and said first wall are each provided with an axial hole
through which
a fastener can pass for fixing said washer assembly to a spindle of said
faucet.
s o Preferably inside of said base is formed with an axially protruding ridge
around the hole
formed therethrough, and said first wall has a reduced thickness portion that
covers said
ridge.
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According to the present invention there is also provided a faucet including
at least:
a washer assembly including a resilient sealing member and a housing;
wherein said resilient sealing member includes a cylindrical wall with
opposite first and
second axial ends, a first wall extending in a radially inward direction from
said first axial
end and said first wall and said cylindrical wall form a cavity into which
fluid can enter
from said second axial end during operation of said washer assembly with said
faucet, and
said housing includes a base and a skirt extending axially from said base to
define a first
Z o seat in which said resilient sealing member is retained, said skirt
extending axially beyond
said second axial end of said cylindrical wall and terminating in an annular
surface having
an inner diameter dimensioned to be substantially radially coterminous with an
outer
diameter of said second axial end when said resilient sealing member is
retained in said
first seat;
i5 a spindle to which said washer assembly is coupled; and,
an insert forming a second seat for washer assembly, said insert provided with
an
annular flange and a spigot extending axially from said flange, said spigot
having an outer
diameter smaller than said inner diameter of said annular surface, wherein
said faucet is in
a fully closed position when said washer assembly is advanced by said spindle
linearly
2 o towards said insert to a position where said spigot abuts said second
axial end of said
cylindrical wall and said annular surface of said skirt abuts said flange.
According to the invention there is also provided a washer assembly for a
faucet including
at least:
a resilient sealing member have a cylindrical wall with opposite first and
second axial ends
and a first wall extending in a radially inward direction from said first
axial end, wherein
said first wall and said cylindrical wall form a cavity into which fluid can
enter from said
second axial end during operation of said washer assembly with faucet; and,
a housing having a base and a skirt extending axially from said base to define
a seat in
which said resilient seating member is retained, said skirt extending axially
beyond said
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second axial end of said cylindrical wall and terminating in an annular
surface having an
inner diameter of substantially the same dimension as an outer diameter of
said second
axial end such that an outer circumferential surface of said second axial end
remains
adjacent said annular surface when said resilient sealing member is retained
in said seat.
Brief Description of the Drawings
An embodiment of the present invention will now be described by way of example
only
with reference to the accompanying drawings in which:
1 o Figure 1 is a schematic representation of the stem of a faucet
incorporating a prior art
washer
Figure 2 is a section drawing of a first embodiment of the present invention
at the time of
initial contact with an insert of a faucet;
Figure 3 is a cross sectional view depicting the washer assembly at full
sealing contact
with the insert; and,
Figure 4 is an isometric view of a sealing member incorporated in the washer
assembly.
Detailed Description of Preferred Embodiments
As shown in Figure 1, the stem 10 of a faucet (not shown) comprises an outer
body 12 and
an axially extending spindle 14. A lower end 16 of the outer body 12 is formed
with an
outer thread for screwing the into the faucet body (not shown). First end 18
of the spindle
2 s 14 nearest the lower end 16 is formed with an increased diameter head 20.
Second
opposite end 22 of the spindle 14 is formed with a plurality of
circumferentially spaced
longitudinally extending ribs 24. A disc type washer 26 is attached to the
head 20 by way
of a screw 28. A handle (not shown) engages the ribs 24 at the second end 22
to facilitate
manual rotation of the spindle 14 in clockwise or anticlockwise directions to
allow
3 0 opening and closing of the faucet.
Figure 2 illustrates an embodiment of the washer assembly 30 in accordance
with the
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present invention together with a typical faucet insert 32. The insert 32 is
in the form of a
short cylindrical tube 34 with a radially outward extending flange 36 formed
about the
outer circumference near an upper end of the tube 34. Extending axially upward
from the
flange 36 is a spigot 38 having a smoothly curved or radiused upper surface
40. A
s shoulder 42 is formed about the outer circumference of the tube 34 between
the flange 36
and spigot 38.
To turn OFF a faucet using the prior art washer 26 SHOWN IN Figure 1, the
spindle 14 is
turned in a clockwise direction to press the washer 26 onto the upper surface
40 of spigot
zo 38. When there is full contact between the surface of the washer 26 and the
upper surface
40, a seal is formed preventing water from passing through a central passage
in the insert
32 thus turning the faucet OFF. If one to continues to turn the spindle 14
further in a
clockwise direction, the washer 26 is pushed harder against the spigot 38
further
compressing the washer 26, and in particular an annulus of the washer 26,
between the
is spigot 38 and the head 20. Assuming that the washer 26 does not tear or
otherwise fail,
the limiting factor on the closing force of the faucet is the compressibility
of the washer
26. That is, the clockwise rotation of the spindle 14 for closing the faucet
is stopped when
the person turning the spindle 14 cannot compress the washer 26 any further.
This of
course may vary from person to person depending on their physical strength.
A washer assembly 30 in accordance with an embodiment of this invention
comprises a
resilient sealing member 44 and a rigid housing 46 that houses the resilient
sealing
member 44. The resilient sealing member 44 has a cylindrical wall 48 with
first axial end
49 and opposite second axial end S1, and a first wall 50 extending radially
inward from the
2 s first axial end 49 forming, with the cylindrical wall 48, a cavity 52 into
which fluid can
enter from the second axial end S 1. The housing 46 has a base 54 and a skirt
extending
axially from the base to define a seat 56. The inside shape of the housing 46
(i.e. the shape
of the seat) is complimentary to the outside shape of the resilient sealing
member 44. The
skirt 56 extends axially beyond the second axial end 51 of cylindrical wall
48, and
3 o terminates in an annular surface 53 having an inner diameter which is
substantially
radially co-terminus with an outer diameter of the second axial end 51 of the
member 44.
As shown in Figure 3, the skirt 56 abuts the flange 36 and seats in the
shoulder 42 when
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the washer assembly 30 is forced or pushed to its maximum extent onto the
insert 32,
corresponding to the fully OFF or closed condition of the faucet.
The resilient sealing member 44 includes a lip or membrane 58 that extends
radially
s inward across the second axial end 51 to an aperture 60 through which fluid
can enter the
cavity 52. The lip or membrane 58 together with first wall 50 and cylindrical
wall 48 in
effect create a circumferential rebate 62 on the inside of the sealing member
44. The
rebate 62 has two effects. Firstly, its provides a region in which fluid
pressure can act to
tend to deform the lip (or membrane) 58 and adjacent portions of the resilient
sealing
i o member 54 outward from the cavity 52. In this way, the pressure of the
fluid itself assists
in the formation of a seal during the closing process by forcing the lip 58
and adjacent
portions of the resilient sealing member against the spigot 38. A further
effect of the
rebate 62 is that it allows a degree of deflection of the lip 58 and
cylindrical wall 48
diagonally inward tending to reduce the size of the rebate 62 as the washer
assembly is
is pushed harder against the insert 32. This has the benefit of providing some
give to the
resilient sealing member 44 in addition to that provided by its natural
resilient.
Both the first wall SO and the base 54 are formed with respective axial holes
64 and 66
arranged in mutual alignment. When the washer assembly 30 is used with the
stem 10,
a o screw 28 passes through the holes 64,66 to fasten the washer assembly 30
to the head 20
of spindle 14.
The inside of the base 54 is formed with a protruding ridge 68 around the hole
66.
Further, the first wall 50 has a portion 70 of reduced thickness that covers
the ridge 68.
2 5 When the screw 28 fastens the washer assembly 30 to the spindle 14, the
head of the screw
28 clamps the portion 70 to the ridge 68. This assists in holding the
resilient sealing
member 44 in the housing 46. However the resilient sealing member 44 is
primarily held
within the housing 46 by relative dimensioning of those components to form an
interference fit.
The operation of the washer assembly 30 will now be described. The washer
assembly 30
is retrofitted to the stem 10 by unscrewing the screw 28, removing the
conventional prior
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art disc washer 26, passing the shank of the screw 28 through the holes 64 and
66 and then
screwing the screw 28 back into the head 20 of spindle 14. Assume that the
faucet is ON
so that water is flowing upwardly through the insert 32. To turn OFF the
faucet, the
spindle 14 is rotated in the clockwise direction. This causes the spindle 14
to move axially
s in a downward direction advancing the washer assembly 30 toward the insert
32. As this
advancement continues, the second axial end 51 of the resilient sealing member
initially
contacts the upper surface 40 of the spigot 38. This constitutes an initial
OFF point for the
faucet. Depending on the fluid pressure however, some fluid may still flow
through the
faucet. To fully turn OFF the faucet, the spindle 14 is further turned in the
clockwise
io direction. Consequently, the resilient sealing member 44 is compressed by
the spigot 38.
Additionally, the lip 58 and adjacent portions of the resilient sealing member
may deflect
diagonally inward in a manner so as to squash the rebate 62. Simultaneously,
fluid
pressure within the cavity 52 and acting within the rebate 62 will have a
counter effect
tending to push the lip 58 against the spigot 38. Thus, the sealing effect is
aided by the
i5 water pressure acting within the resilient sealing member 44. Eventually as
one continues
to rotate the spindle 14 in the clockwise direction, the skirt 56, and more
particularly the
annular surface 53 thereof, contacts the flange 36 seating in the shoulder 42.
This
constitutes the axial limit to the downward motion of the pressure assembly
30. If one
attempts to further turn the spindle 14 in the clockwise direction additional
force is applied
2 o to the housing 46 protecting the resilient sealing member 44 from
excessive
shearing/tearing forces.
It is envisaged that the housing would be made from a plastics material such
as ACETAL.
However alternately, the housing 46 may be made from a metal or alloy
including, but not
2 s limited to, brass. The resilient sealing member 44 is advantageously made
from a rubber
material and preferably a rubber material having a hardness on the Shore scale
in the order
of 60 to 100. One particularly well suited material is SANTOPRENE.
All modifications and variations of the above disclosed embodiment as would be
apparent
3 o to those of relevant skill in the relevant arts are considered to be
within the scope of the
present invention that nature of which is to be determined from the above
description and
the following claims.
