Valves and valve actuation – With means to increase head and seat contact pressure – Fluid pressure
Reexamination Certificate
1999-10-13
2002-03-12
Kwon, John (Department: 3754)
Valves and valve actuation
With means to increase head and seat contact pressure
Fluid pressure
C251S332000
Reexamination Certificate
active
06354565
ABSTRACT:
BACKGROUND OF THE INVENTION
The parent application deals with sealing members and valve closure members for taps commonly available in Australia. Such taps 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 up and down within the tap body. The prior art washer assembly comprises a resilient disc fixed to a metal alloy or rigid plastic backing plate with an integral pin extending upwardly from the centre of the backing plate. The pin of the washer assembly is received within a hole formed axially in the lower end of the spindle located within the tap body. By turning the spindle in a first direction the washer assembly can be pushed down onto the seat to close the tap. By turning the spindle in the opposite direction, the wash assembly is lifted largely by water pressure to open the tap. The quality of the seal in the tap is dependent on both the form of the washer assembly and the seat. In the typical Australian tap, the tap body is formed by casting and as such, the seat has the normal imperfections associated with casting, namely relatively rough, and sometimes unlevel, surface. In order to compensate for these imperfections in the seat, the parent application discloses a sealing member and valve closure member incorporating the sealing member with improved sealing capabilities. In general terms the sealing member is in the form of a resilient bladder that is inflated by the pressure of the water to assist in sealing against the seat.
However, faucets typically available in the USA and Asia are of different construction. Specifically, the washer assembly typically is in the form of a disc of resilient material as fastened by a screw to the end of the spindle. In this way, the washer turns with the spindle. In contrast, with the Australian style tap, the washer is simply retained by the spindle and does not necessarily rotate with the spindle. Reasonably good sealing is provided in the US style faucet by virtue of having a closely toleranced insert that separately machined and placed within the faucet body to form the washer seat. The insert is substantially cylindrical in form and has, at an upper end, a radially extending flange used to support the insert within the faucet body and radially inward thereof, an upwardly extending spigot. The spigot is formed with smoothly curved upper surface. The washer in the faucet pushes against the curved surface of the spigot when closing the tap.
A fundamental problem however remains with the US style faucet that because the washer turns with the spindle it is subject to excessive wear and tear. This is because substantially all of the downwards pressure applied by turning the spindle is transmitted by the resilient washer onto the insert. The harder one turns the spindle the greater the compression and fictional forces on the washer. If the washer suffers a catastrophic failure, e.g. 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 particularly suited to the US style faucet.
According to the present invention there is provided a washer assembly for a faucet the washer assembly comprising:
a resilient sealing member and a rigid housing that houses the resilient sealing member, the resilient sealing member having a cylindrical wall with opposite first and second axial ends and a first wall extending across the first axial end forming with said cylindrical wall a cavity into which fluid can enter from the second axial end;
the housing having a base and a skirt depending from the base with the inside of the housing having a shape complimentary to the outside shape of the resilient sealing member, the housing and the resilient sealing member relatively dimensioned so that the skirt extends axially beyond the second axial end of the cylindrical wall. Preferably the resilient sealing member is provided with a lip or membrane extending radially inward across the second axial end to an aperture through which the fluid can flow to enter the cavity, the lip or membrane creating, together with the cylindrical wall and the first wall, a rebate in the sealing member in which fluid pressure can act to tend to deform the lip and adjacent portions of the resilient sealing member outward from the cavity.
Preferably the base and the first wall are each formed with an axial hole, said holes being in mutual alignment and through which a fastener can pass for fixing the washer assembly to a spindle of the faucet.
Preferably the inside of the base is formed with a protruding ridge around the hole formed therethrough, and the first wall has a reduced thickness portion that covers the ridge, the fastener clamping the reduced thickness portion to the ridge when it fixes the washer assembly to the spindle.
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Keasel Eric
Kwon John
LandOfFree
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