BACKGROUND TO THE INVENTION There are a myriad of known seals in existence of which an "O-Ring"seal is probably the most predominant. The"O- Ring"seal, as is apparent from its name, is tubular in cross-section and is generally circular in its profile shape. Inner and outer annulus surfaces of the"O-Ring" seal are designed to seat in corresponding recesses formed in inner and outer tubular members, respectively, between which a seal is effected. The seal is usually constructed of a rubber material, such as that available under the trademark VITON, and relies on its resilience together with air pressure within the"O-Ring"seal to promote the seal. The conventional"O-Ring"seal of this form has at least the following drawbacks: i) the"O-Ring"seal, by the very nature of its circular cross-section, tends to unseat from the recess within which it is located; and ii) the"O-Ring"seal is limited in its application depending on pressure requirements and physical characteristics of the components to be sealed.

US Patent No. 4,298,206 generally relates to packing adapted to close or seal a joint in a pipeline to prevent leakage of any fluid flowing therethrough. The flexible packing includes an outer cylindrical wall to an inner peripheral cylindrical wall via an annular portion. The outer cylindrical wall is designed to seat within a pipe joint and the inner peripheral cylindrical wall seals

against a coaxial pipe located within the pipe joint. The inner wall presses against the outer wall so as to form the seal. The packing gland relies upon this pressure of the inner wall against the outer wall to form an effective seal which may not be effective when the inner pipe is axially displaced relative to the outer pipe, such as under conditions of vibration. In an alternative embodiment of the flexible packing of US 4,298,206 an O- ring shaped outer peripheral portion of the packing gland is press-fit within an annular groove in a pipe joint.

Although this press-fitting of the packing gland is intended to minimise the likelihood of its dislodgment, the peripheral sealing portion by nature of its design tends to draw the 0-ring shaped portion from the annular groove.

SUMMARY OF THE INVENTION According to one aspect of the present invention there is provided an annular sealing element being adapted to retractably mount to one tubular component and operatively cooperate with another tubular component to provide a seal across an annular gap between said components, said sealing element comprising: a mounting portion being adapted to at least partly retractably seat within an annular recess in said one tubular component, said mounting portion in cross-section being shaped substantially complementary to the annular recess; and a sealing portion being connected to the mounting portion and at least partly formed of a resiliently flexible material whereby relative movement between said tubular components in an axial and/or radial direction effects deformation of the sealing portion which is biased into contact with the other tubular component to provide

the seal therebetween, said sealing portion being configured relative to the mounting portion so as to urge the mounting portion into seating engagement with the annular recess of said one tubular component.

Preferably the sealing portion includes a tongue member which is integral with and extends outwardly from the mounting portion, the tongue member having opposing surfaces one only of which is configured to engage the other tubular component to provide the seal.

Typically said one engaging surface of the tongue member includes adjacent convex and concave surfaces with the concave surface terminating in and defining a lip portion, said convex surface and the lip portion both being configured to engage the other component to form a dual seal. More typically the other of the opposing tongue surfaces is shaped complementary to said one surface wherein the tongue progressively tapers outwardly to form the lip portion.

Preferably at least part of the mounting portion is in cross-section shaped complementary to the annular recess formed in said one component, the mounting portion being designed to press-fit within the recess. More preferably the mounting portion is in cross-section shaped orthogonal.

Typically the mounting portion includes a recess in its rear surface opposite the sealing portion, the recess being adapted to engage a protrusion in said one component to assist in mounting of the sealing element to said component. More typically the recess and the protrusion

are in the form of a complementary shaped keyway and key which are configured to engage one another.

Preferably the sealing element is at least partly constructed of a resiliently flexible polymeric material such as a nylon-based material. Alternatively or additionally the mounting portion is at least partly fabricated from a metallic material such as steel.

Typically the mounting portion is of a relatively rigid construction whereby in use it provides adequate support for the sealing portion whilst retaining its mount to said one component. More typically the mounting support is appropriately sized to provide this rigidity.

BRIEF DESCRIPTION OF THE DRAWINGS In order to facilitate a better understanding of the nature of the present invention preferred embodiments of a sealing element will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is an exploded perspective view of a sealing element together with adjacent components between which a seal is to be formed; Figure 2 is a perspective view of the sealing element of Figure 1 fitted to one of the components; Figures 3 and 4 are enlarged cross-sectional views of the sealing element of Figure 2 in fitting operation; Figure 5 is a perspective view of the sealing element of Figure 1 fitted to one component and designed to sealingly engage a variant of the other component; Figure 6 is an exploded perspective view of another sealing element together with components between which it is to form a seal;

Figure 7 is an exploded perspective view of a further sealing element together with components between which it is to form a seal; Figure 8 is a perspective view of a pair of the sealing elements of Figure 7 fitted to one component; and Figure 9 is a schematic illustration of interactive forces of the sealing element in fitting operation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in Figures 1 and 2 there is a sealing element 10 being adapted to mount to one component 12 and operatively cooperate with another component 14 to provide a seal therebetween. In this example said components 12 and 14 consist of an outer and an inner tubular member axially aligned with one another. The outer tubular member 12 has an inside diameter which is slightly greater than the outside diameter of the inner tubular member 14 wherein an annulus gap is formed between the tubular members 12 and 14 when they are axially brought together. The sealing element 10 is designed to provide a seal across the annulus gap.

The sealing element 10 is designed to locate within a ring-shaped channel or seat 16 formed in an inner surface of the outer tubular member 12. In this embodiment the inner tubular member 14 is axially slid within the outer tubular member 12 across the sealing element 10.

The sealing element 10 of this particular construction comprises a mounting portion 18 which is connected to a sealing portion shown generally as 20. The mounting and sealing portions 18 and 20 are formed integral with one another. The mounting portion 18 is in cross-section shaped complementary to the seat 16 of the outer tubular

member 12. Thus, the sealing element 10 is designed to press-fit via the mounting portion 18 into the seat 16 of the outer tubular member 12. The sealing portion 20 is in this example formed as an inwardly protruding tapered tongue which is connected and oriented generally perpendicular to the mounting portion 18. The sealing portion or tongue 20 is formed integral with the mounting portion 18 approximately midway between its upper and lower edges.

As best shown in Figures 3 and 4 the tapered tongue 20 is defined or formed by opposing upper and lower surfaces 22 and 24 which are shaped complementary to one another. The upper and lower tongue surfaces 22 and 24 terminate in and define a lip portion 26. Importantly, the upper surface 22 includes adjacent convex and concave surfaces 28 and 30, respectively, with the concave surface 30 terminating in the lip portion 26. In sealing operation the convex surface 28 together with the lip portion 26 engage an outer wall of the inner tubular member 14 to form a dual seal.

A rear surface of the seating portion 18 includes a recess or keyway 32 which is engaged by a protrusion or key 34 formed in the seat 16 of the outer tubular member 12. The keyway 32 and key 34 extends circumferentially about the sealing element 10 and the seat 16, respectively. The sealing element 10 of this embodiment is formed of an appropriate polymeric material which is injection moulded.

The preferred polymeric material is a nylon-based material although this may vary depending on the application and desired life of the seal 10. In any event at least the sealing portion 20 of the seal is to be fabricated from a resiliently flexible material which can be deformed to

form a seal as depicted in Figures 3 and 4. The sealing element 10 may be of a composite material construction where for example the mounting portion 18 is at least partly formed from a steel ring.

Importantly the sealing portion 20 and the mounting portion 18 are together configured so that seating of the sealing element 10 is promoted by the bias force exerted on the tapered tongue 20 when it is deformed by the inner tubular member 14. Thus interaction between the seating portion 20 and the mounting portion 18 avoids movement of the sealing element 10 relative to the outer tubular member 12. This is a particular problem with conventional "O-Ring"seals where the seal"rolls out"from the recess in which it is seated. On the other hand, the sealing element 10 of this embodiment of the invention provides a "non-slip"mounting of the seal 10.

The sealing element 10 of Figure 5 is substantially identical to that described in the preceding paragraphs.

However, in this example, the other component 36 with which the sealing element 10 is designed to engage is formed different to the inner tubular member 14 of Figures 1 to 4. In this example the other component 36 is a tubular member of similar dimensions to the outer tubular member 12 but with its end tapered inwardly to define a circumferential flange 38 which locates within the outer tubular member 12. This alternative tubular member 36 is slid axially within the outer tubular member 12 until corresponding end surfaces 40 and 42 abut. In this position the sealing element 10 forms a dual seal between the outer and inner components 12 and 38 as illustrated in Figure 4.

Figures 6 and 7 show two (2) alternative embodiments of the sealing element according to the present invention.

In order to avoid repetition and for ease of reference those components of these alternative embodiments which are similar to the sealing element of Figures 1 to 5 will be designated with an additional"0". For example, the sealing element itself is designated as 100 and the outer and inner tubular elements 120 and 140, respectively.

The sealing elements 100 of Figures 6 and 7 vary slightly only in relation to the cross-sectional shape of the mounting portion 180. The mounting portion of Figure 6 is generally rectangular in cross-section whereas it is in the form of a parallelogram in Figure 7. In both embodiments the mounting portion 180 has an increased wall thickness compared to that of the preceding embodiments.

The mounting portion 180 is thus of a greater rigidity and provides firmer mounting or fitting of the sealing element 100 to the outer tubular member 120. This may allow moulding of the sealing element 100 and in particular its sealing portion or tongue 200 in a more resiliently flexible material. Otherwise, the tongue 200 of the sealing element 100 operates and is of an identical construction to that of the preceding example.

Figure 8 depicts two of the alternative sealing elements such as 100 mounted adjacent one another within the outer tubular member 120. These sealing elements include a keyway 320 formed in a rear surface of their mounting portion 180 similar to that shown in Figures 3 and 4. The axially spaced sealing elements 100 provide additional sealing where required. In this instance, each of the tongue members 200 provides a dual seal as shown in Figure 4. It should be appreciated that any number of the

sealing elements 10 or 100 may be used depending on the application.

Figure 9 schematically illustrates forces exerted within the sealing element such as 10 when it is located between said one and the other components 12 and 14. The solid "arrowed"lines represent the vector forces present in the sealing element 10 in this position. Importantly, the tension stresses at the lip portion 26 assist in sealing of the sealing portion 20 about the inner tubular member 14. This is also promoted by the convex surface 28 which is pressed against the inner member 14 and urges the lip portion 26 against said member 14. The forces exerted on the sealing portion 20 are transferred to the seating portion 18 so as to promote its engagement or fitting in the seat 16.

Now that several preferred embodiments of the present invention have been described in some detail it will be apparent to those skilled in the relevant art that the sealing elements have at least the following advantages over the admitted prior art: (i) the sealing elements firmly seat or locate within one of a pair of components between which a seal is to be formed; (ii) the sealing element and in particular its sealing portion can be configured to provide one or more effective seals such as that described by the tapered tongue ; and (iii) the sealing element can be designed in configuration or material selection to suit a vast range of applications.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described.

For example, the sealing element itself may be manufactured from a range of appropriate materials provided the sealing portion is constructed of a resiliently flexible material which functions as broadly defined. For example the sealing element may be fabricated from a flexible or semi-flexible metal such as a thermal metal. The sealing element depending on the material selection and geometry required may be injection moulded, rotationally moulded, or extruded and bonded where necessary. The sealing element may be used in a range of applications where one or both of the tubular components are generally stationary or move relative to one another. This movement may be by way of axial sliding or rotation. For example, the sealing element is appropriate as a crank shaft seal. The sealing element is particularly suited to applications where there is radial displacement of one of the tubular components relative to the other, for example under conditions of vibration. The ability of the sealing element to permit radial movement between the coaxial tubular components reduces the need for the never ending increase of precision and accuracy in machining/fabrication of these components and accommodates less stringent tolerances and variations which occur as a result of wear and fatigue between these components.

All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.