Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
A SEALING APPARATUS
Document Type and Number:
WIPO Patent Application WO/2005/058585
Kind Code:
A1
Abstract:
An apparatus for sealing an opening in a sheet material, the apparatus comprising a first element (3) and a second element (5), the first element (3) being configured to allow it to pass through the opening and to be positioned to encircle the opening, without undergoing deformation, wherein, in use, the first and second elements (3, 5) are co-operable to seal the opening.

Inventors:
SANTY JOHN JAMES (GB)
Application Number:
PCT/GB2004/005314
Publication Date:
June 30, 2005
Filing Date:
December 16, 2004
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
SANTY JOHN JAMES (GB)
International Classes:
B29C73/14; F16L55/16; F16L55/168; (IPC1-7): B29C73/14
Domestic Patent References:
WO1993025381A11993-12-23
Foreign References:
GB2329880A1999-04-07
GB2201130A1988-08-24
GB424129A1935-02-11
US5350481A1994-09-27
Attorney, Agent or Firm:
Merrifield, Sarah Elizabeth (Verulam Gardens 70 Gray's Inn Road, London WC1X 8BT, GB)
Download PDF:
Claims:
CLAIMS
1. An apparatus for at least substantially sealing an opening in a sheet material, the apparatus comprising a first element and a second element; the first element being configured to allow it to pass through the opening and to be positioned to encircle the opening, substantially without the first element undergoing deformation; wherein, in use, the first and second elements are cooperable at least substantially to seal the opening.
2. An apparatus for at least substantially sealing an opening in a sheet material, the apparatus comprising a first element and a second element; the first element being noncircular to allow it to pass through the opening and to be positioned to encircle the opening; wherein, in use, the first and second elements are cooperable at least substantially to seal the opening.
3. An apparatus as claimed in any one of claims 1 or 2, further comprising alignment means for aligning the first and second elements relative to each other.
4. An apparatus for at least substantially sealing an opening in a sheet material, the apparatus comprising a first element and a second element and alignment means for aligning the first element in a predetermined orientation relative to the second element; wherein in use, the first and second elements are cooperable at least substantially to seal the opening.
5. An apparatus as claimed in any one of claims 1 to 4, wherein the first element comprises a first surface and the second element comprises a second surface, said first and second surfaces being cooperable in use to create a seal around the opening.
6. An apparatus as claimed in any preceding claim, wherein at least one of the first surface and the second surface is provided with at least one ridge.
7. An apparatus as claimed in claim 6, wherein the at least one ridge has a parabolic or a'V'shaped cross sectional profile.
8. An apparatus as claimed in any one of claim 6 or claim 7, wherein the other or each of the said first and second surfaces is provided with a channel for receiving said at least one ridge.
9. An apparatus as claimed in any preceding claim further comprising, a fixing means for fixing the first element and the second element in position relative to each other and/or in position relative to the opening.
10. An apparatus as claimed in claim 9, wherein the fixing means comprises a fixed member and a movable member.
11. An apparatus as claimed in claim 10, wherein the movable member is a rotatable member, the fixed member and the rotatable member having complementary screw threads.
12. An apparatus as claimed in any one of claims 10 or 11, wherein the fixed member is provided on the first element.
13. An apparatus as claimed in any one of claims 10,11 or 12, wherein the fixed member is a stud having an external screw thread.
14. An apparatus as claimed in any one of claims 11,12 or 13, wherein the rotatable member is a wheel having an internal screw thread.
15. An apparatus as claimed in any one of claims 9 to 14, wherein in use the mechanism clamps the first element tothe second element.
16. An apparatus as claimed in any one of claims 10 to 15 when dependent directly or indirectly on claim 3 or 4, wherein the fixed member and at least one of the first element and the second element are provided with alignment means.
17. An apparatus as claimed in claim 16, wherein the transverse crosssectional profile of the fixed member and the shape of the aperture in the second member are complementary and noncircular to provide said alignment means.
18. An apparatus as claimed in claim 17, wherein the transverse crosssectional profile of the fixed member has at least one straight side.
19. An apparatus as claimed in any preceding claim, wherein the length of the first element is greater than the width of the first element.
20. An apparatus as claimed in any preceding claim, wherein the aspect ratio of the first element is greater than 1.25, 1.5, 1.75, 2,2. 25,2. 5,2. 75 or 3.
21. An apparatus as claimed in any preceding claim, further comprising a flexible element.
22. An apparatus as claimed in claim 21, wherein the flexible element is attached to the first element.
23. An apparatus as claimed in any one of claims 21 or 22, wherein the flexible element extends through the second element.
24. An apparatus as claimed in any one of claims 21,22 or 23, wherein the flexible element is provided with a toggle.
25. A flexible element as claimed in any one of claims 21 to 24, wherein the flexible element is a cord.
26. An apparatus as claimed in any preceding claim wherein, the first element and/or the second element are substantially rigid.
27. A method of at least substantially sealing an opening in a sheet material employing the apparatus as claimed in any one of the preceding claims comprising the steps of: (a) placing the first element adjacent to a first side of the material; (b) placing the second element adjacent to a second side of the material; and (c) fixing the first element and the second element in position relative to each other at least substantially to seal the opening.
28. A method as claimed in claim 25, further comprising the step of inserting the first element through the opening.
29. A method of attachment as claimed in claim 28, further comprising the step of positioning the first element to encircle the opening.
30. A method of attachment as claimed in any one of claims 27 to 29, further comprising the step of enlarging the opening to enable the first element to pass through.
31. A kit of parts for making the apparatus as claimed in any preceding claim.
32. An apparatus for at least substantially sealing an opening substantially as hereinbefore described and with reference to Figures 1 to 4; Figure 5; or Figures 6 and 7.
33. A method of at least substantially sealing an opening substantially as hereinbefore described and with reference to Figures 1 to 4; Figure 5; or Figures 6 and 7.
Description:
A SEALING APPARATUS The present invention relates to apparatus for sealing openings in sheet materials. More specifically, the present invention relates to a mechanical sealing apparatus for sealing holes, tears and. punctures in flexible sheet materials.

Ruptures in the flexible material of, for example, inflatable boats, swimming pools and car soft roofs are common. Often an instantaneous seal is required. This negates the use of known adhesive seals which must be left for a period of time to cure and furthermore can generally only be applied to surfaces which have been properly prepared if a leak-proof bond is to be achieved. In these circumstances, a mechanical sealing apparatus may be used.

There are a number of mechanical sealing apparatus known in the prior art, such as those disclosed in international patent applications PCT/GB93/01263 and PCT/GB92/02362. However, such apparatus may lack functionality and additionally may be complex and hence expensive to produce. There is therefore a requirement for a design of mechanical sealing apparatus that is simple, and hence cheap to manufacture and that overcomes the disadvantages of the prior art.

According to a first aspect, the present invention provides an apparatus for at least substantially sealing an opening in a sheet material, the apparatus comprising a first element and a second element, the first element being configured to allow it to pass through the opening and to be positioned to encircle the opening, substantially without the first element undergoing deformation; wherein, in use,

the first and second elements are co-operable at least substantially to seal the opening.

Thus, the present invention provides a simple apparatus that may be utilised to seal an opening in a material when only one side of the material is accessible.

According to a further aspect, the present invention provides an apparatus for at least substantially sealing an opening in a sheet material, the apparatus comprising a first element and a second element, the first element being non-circular to allow it to pass through the opening and to be positioned to encircle the opening; wherein, in use, the first and second elements are co-operable at least substantially to seal the opening.

The first element may be any non-circular shape, provided that its length is greater than its width.

Preferably, the apparatus further comprises alignment means for aligning the first and second elements relative to each other. When adjacent to the internal surface of the material the first element may be largely obscured by the material and hence means may be required to ascertain the alignment of the first plate relative to the opening.

According to a still further aspect, the present invention provides an apparatus for at least substantially sealing an opening in a sheet material, the apparatus comprising a first element and a second element and alignment means for aligning the first element in a predetermined orientation relative to the second element; wherein, in use, the first and second elements are co- operable at least substantially to seal the opening.

Preferably, the first element comprises a first surface and the second element comprises a second surface, said first and second surfaces being co-operable in use to create

a seal around the opening. In use, the material is preferably provided between the first and second elements.

In a preferred embodiment, the first and second surfaces are in the form of planar surfaces. Alternatively, the first and second surfaces may be in the form of complementary curved (i. e. non-planar) surfaces. The first and second surfaces may be curved in two dimensions (e. g. to define a portion of the surface of a cylinder) or may be curved in three dimensions (e. g. to define a portion of the surface of a sphere). The complementary curved surfaces may assist in alignment of the first and second elements relative to each other. The curved profile may be determined by the form of the flexible material to be repaired.

In a preferred embodiment, at least one of the first surface and the second surface are provided with at least one ridge. The apparatus may be provided with a ridge on each of the first and second surfaces. The first surface and/or the second surface may each be provided with two or more ridges. Preferably, the ridge (s) are formed as closed loop (s) which encircle the opening. It is envisaged that the ridges may be configured differently. For example, the ridges may be open-ended features arranged to form a labyrinth type seal.

Alternatively, at least one of the first element and the second element may be provided with a rubber"O-ring" for sealing the apparatus against a rigid material, for example a glass reinforced plastic hull.

Preferably, the at least one ridge has a parabolic or a 'V'shaped cross-sectional profile. However, any suitable cross-sectional profile may be utilised.

It is envisaged that, in addition, the other or each of the said first and second surfaces may be provided with a channel for receiving said at least one ridge.

In a preferred embodiment, the apparatus may further comprise fixing means for fixing the first element and the second element in position relative to each other and/or in position relative to the opening.

Preferably, the fixing means comprises a fixed member and a movable member. Preferably, the movable member is a rotatable member, the fixed member and the rotatable member having complementary screw threads. However, the first and second elements may be fixed together by alternate means.

For example, the mechanism may be a"snap"fastening arrangement or a"cam-lock"arrangement. Indeed, in certain applications, it may be desirable to attach the first and second elements together using adhesive.

Preferably, the fixed member is provided on the first element. Most preferably, the fixed member is formed integrally with the first element. Alternatively, the fixed member may be provided as a separate component. Preferably, the fixed member is a stud having an external screw thread and the rotatable member is a wheel having an internal screw thread.

To enable a shorter stud to be provided, whilst still maintaining an engagement zone of the internal and external threads that is sufficient to securely fix the first element to the second element, the second element may be provided with a recess into which the rotatable member is at least partially received.

Preferably, in use, the fixing means clamps the first element to the second element.

In a preferred embodiment, the fixed member and at least one of the first element and the second element may be provided with alignment means. Preferably, the alignment means are provided by the fixed member and the second element and alignment is achieved by co-operation between the fixed member and the second element. For example, the transverse cross-sectional profile of the fixed member and the shape of the aperture in the second member may be complementary and non-circular to provide said alignment means. The complementary non-circular profiles may help to prevent relative rotation between the first and second elements which may otherwise occur when the elements are being fixed in position.

More preferably, the transverse cross-sectional profile of the fixed member has at least one straight side. However, the profile of the fixed member may be of any non-circular form.

So that the apparatus can create a seal around the opening, it is preferable that the length of the first element is greater than the width of the first element. The first element can then be passed through an opening that need only be as wide as the width of the first element. The opening does not need to be stretched to enable the first element to pass through. The first element can then be positioned so that its greater length dimension covers the opening.

In a preferred embodiment, in plan form the first element is an oval or an ellipse. However, the first element may be of any suitable shape. Preferably, the aspect ratio (i. e. the ratio of the length to the width) of the first element is greater than 1.25, 1.5, 1.75, 2,2. 25,2. 5,2. 75 or 3. Preferably the aspect ratio is not greater than 3 or

3.5. The second element preferably has the same shape in plan form as the first element.

To assist in handling and use, the apparatus may further comprise a flexible element. Preferably, the flexible element is attached to the first element. In addition, the flexible element may extend through the second element. The flexible element enables the first element to be inserted through the opening and then to be pulled into position adjacent to the inside surface of the material. In addition, the flexible element may be provided with a toggle. The toggle may be of any suitable form that enables it to act as a gripping member to enable the first element to be pulled into position and to enable tension to be retained in the flexible element so that the first element may be retained, at least temporarily, in that position. The toggle may also act to retain all of the components of the apparatus together on the flexible element.

Preferably, the flexible element is a cord. However, the flexible element may be of any suitable alternative form, for example it may be a strap.

In a preferred embodiment, the first element and/or the second element are substantially rigid. The elements can be rigid as they do not need to be deformed to pass through the opening. A rigid construction provides for simpler and cheaper manufacture. Rigid first and second elements may be provided with rigid ridges that can seal against a flexible material without the need to be provided with separate sealing surfaces. Of course, the first element and/or the second element may be made of a flexible material.

Viewed from a yet still further aspect, the present invention provides a method of at least substantially sealing an opening in a sheet material employing the

apparatus as described herein, the method comprising the steps of, placing the first element adjacent to a first side of the material, placing the second element adjacent to a second side of the material and fixing the first element and the second element in position relative to each other at least substantially to seal the opening.

The method may further comprise the step of inserting the first element through the opening.

So that the apparatus can seal the opening, it is preferable that the length of the first element is greater than the width of the first element. The first element can then initially be passed through an opening that need only be as wide as the width of the first element. The first element can then subsequently be positioned so that its greater length dimension covers the opening. Preferably, the first element is rotated through 90° relative to the opening.

The apparatus may be used to seal openings on inflatable structures, for example, inflatable boats. In the case of inflatable boats and other pressurised articles the pressure may maintain the first element in position and the method may include the step of removing the second element.

The method may further comprise the step of enlarging the opening to enable the first element to pass through.

Viewed from a still further aspect, the present invention provides an apparatus for at least substantially sealing an opening in a sheet material, the apparatus comprising a first element and a second element; the first element being configured to allow it to pass through the opening and to be positioned to enclose or cover the opening, substantially without the first element undergoing

deformation; wherein, in use, the first and second elements are co-operable at least substantially to seal the opening.

Viewed from a yet still further aspect, the present invention provides an apparatus for at least substantially sealing an opening in a sheet material, the apparatus comprising a first element and a second element; the first element being non-circular to allow it to pass through the opening and to be positioned to enclose or cover the opening; wherein, in use, the first and second elements are co-operable at least substantially to seal the opening.

The present invention also provides for a kit of parts for making the apparatus as described herein.

Two embodiments of a mechanical sealing apparatus constructed in accordance with the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a mechanical sealing apparatus according to the first embodiment of the present invention; Figure 2 is an exploded perspective view of a mechanical sealing apparatus according to the first embodiment of the present invention ; Figure 3 is an exploded elevation view of a mechanical sealing apparatus according to the first embodiment of the present invention.

Figure 4 is an elevation view of an assembled mechanical sealing apparatus according to the first embodiment of the present invention; Figure 5 is a perspective view of a mechanical sealing apparatus according to the first embodiment of the present invention sealing a hole in the tube of a rigid inflatable boat;

Figure 6 is an exploded perspective view of a mechanical sealing apparatus according to the second embodiment of the present invention ; and Figure 7 is a perspective view of a mechanical sealing apparatus according to the second embodiment of the present invention.

The first embodiment of the mechanical sealing apparatus 1, shown in Figure 1, comprises a first element 3, a second element 5, a stud 7 and a wheel 9. The first and second elements are defined herein with reference to a longitudinal axis Y-Y and a transverse axis X-X.

The first element 3 is provided with a generally planar first co-operating surface 11 as shown in Figure 2. The first surface 11 comprises an outer ridge 13 and an inner ridge 15. The ridges 13,15 run circumferentially inside and adjacent to the rim of the first element 3. The cross- sectional form of the ridges 13, 15, in a plane perpendicular to the plane of the first co-operating surface 11, is parabolic.

The second element 5 is provided with an aperture 17 which, in use, locates around the stud 7. The aperture 17 is in the form of a truncated circle, having two opposed flat sides 19. The sides 19 are aligned perpendicular to the transverse axis X-X, as shown in Figure 2. The second element 5 is provided with a generally planar second co- operating surface 21. The second surface 21 is in the form of a band running circumferentially inside and adjacent to the rim of the second element 5.

The stud 7 is attached to the first element 3 and is provided with an external thread 23. The stud 7 is provided with two opposed flats 25, which run parallel to, and either side of, the longitudinal axis of the stud 7. The flats 25

are aligned perpendicular to the transverse axis X-X, and are complementary to the flat sides 19 provided on the aperture 17.

The wheel 9 is generally circular and has a substantially semi-circular profile in radial cross-section.

The wheel 9 is provided with a plurality of semi-circular finger grips 29 around its circumference and has a central hole 31 provided with a female thread 33, complementary to the external thread 23 of the stud 7.

To increase their rigidity, the elements 3,5 have domed cross-sectional profiles as shown in Figures 3 and 4. To decrease their material mass, elements 3,5 are hollow and are provided with reinforcing webs 35, as shown in Figure 2.

Both the first and second elements 3,5 have an elliptical plan form.

In order to obtain the required tolerances and to enable relatively high volume, low cost, manufacture, it is preferred that the components of the apparatus 1 are manufactured from a plastics material using injection moulding techniques.

To carry out a repair, the elements 3,5 are located such that the first and second surfaces face each other and the stud extends through the hole to be repaired. The second surface 21 and the first surface 11 are located such that they encircle the hole on respective sides of the material.

When the elements 3,5 are fixed to the material the surfaces 21,11 co-operate to create a seal around the hole.

The sealing apparatus 1 of the present invention utilises a single point contact sealing arrangement. The material to be sealed is fixed between the second surface 21 and the ridges 13,15 provided on the first surface 11. The advantage of this arrangement is that, as the contact area

between the elements 3,5 is low, a force applied to the elements 3,5 creates a relatively high pressure at the co- operating surfaces 21,11.

An advantageous feature of the present invention is that the co-operating surfaces 21,11 can be manufactured integrally with the first and second element 3,5, without the need to provide an additional material to act as a sealing element. The single point contact sealing arrangement utilises the properties of the material to provide the seal. For example, a typical material used in an inflatable boat consists of a Neoprene# core surrounded by a layer of Hypalon#. The properties of the material are such that the ridges 13,15 on the first surface 11 co-operate with the second surface 21 to form a seal with the material.

There is therefore no requirement to provide an additional sealing member on the ridges 13,15.

When the sealing apparatus 1 is used to seal internally pressurised objects, for example the tube of an inflatable boat, the internal pressure alone may be sufficient to maintain a seal between the ridges 13,15 and the material.

The force supplied by the fixing mechanism becomes redundant and the second element 5 may be removed. However, it is advantageous to retain the second element 5 in position to prevent the first element 3 from being inadvertently pushed away from the material and the seal being broken.

The preferred embodiment of the present invention is provided with two ridges 13,15 to provide a particularly efficient sealing arrangement. The provision of two ridges 13,15 helps to prevent a break in the seal resulting from misalignment between the elements 3,5.

It is envisaged that the sealing apparatus 1 will be used in two situations. The first and most straightforward

application of the mechanical sealing apparatus 1 is to seal a hole in a sheet material where both sides of the material are accessible. Typically, this might be a seal applied to the skin of a swimming pool. The second application of the sealing apparatus 1 is to seal a hole in a material when only one side of the sheet material is accessible. Typically this might be a seal applied to an inflatable boat.

In the first application, the first element 3 is placed adjacent to one side of the material and the second element 5 is placed adjacent to the other side of the material, opposite to first element 3. The stud 7, attached to the first element 3, is passed through the hole in the material and the first element 3 is moved towards the material until the ridges 13,15 are in contact with the material. If necessary, the hole in the material can be enlarged to admit the stud 7. The second element 5 is then located over the stud 7. The flat surfaces 19 provided on the aperture 17 of the second element 5 are complementary to those of the stud 7, so that when the second element 5 is located over the stud 7, the elements 3,5 are aligned. Once the second element 5 has been pushed up against the material, prior to the wheel 9 being engaged, the sealing apparatus 1 is aligned correctly in relation to the hole using the flats 25, provided on the stud 7, as a guide. Once the wheel 9 is engaged with the stud 7 it can be rotated so that it comes into contact with the top surface of the second element 5.

Prior to any further rotation of the wheel 9, to fix the first and second elements to the material, any creases in the material are removed at this stage. During the fixing procedure, the material is trapped between the second surface 21 and the ridges 13,15 provided on the first surface 11. It is sufficient to tighten the wheel 9 by hand

to obtain the necessary force to provide a seal between the sealing apparatus 1 and the material.

When the internal surface of a material to be sealed is not accessible the first element 3 needs to be passed through the hole so that it can be located adjacent to the inside surface of the material.

To create a seal around the hole the area enclosed within the first surface 11 should be at least as large as that of the hole. For this reason, the first element 3 is provided with a shape that has a greater length along the longitudinal axis Y-Y than along a transverse axis X-X. It therefore has an aspect ratio of greater than 1, i. e. it has a length greater than its width. In the preferred embodiment, the first element 3 is elliptical and has an aspect ratio of approximately 2. The hole should preferably be in the form of a slit.

In some circumstances it may be necessary to enlarge the hole to a width corresponding to the maximum width of the first element 3.

To aid with handling of the first element 3 the sealing apparatus 1 may be provided with a cord 37, as shown in Figure 5. When locating the first element 3 adjacent to the inside surface of the material the cord 37 enables the first element 3 to be inserted through the hole, whilst still enabling the user to control it. The user can hold the first element 3 in place using the cord 37, while the other hand can be used to align the first element 3 relative to the hole. After the first element 3 has been passed through the hole in the material, withdrawal of the cord 37 away from the material draws the first element 3 against the inside of the sheet material. Manipulation of the cord can also assist in aligning the first element 3 relative to the hole.

The first element 3 is passed through the hole in a direction perpendicular to its width, i. e. in a direction along axis Y-Y, as shown in Figure 2. Once through the hole the first element 3 is suspended on the cord 37 held by the user. To locate the first element 3 adjacent to the inside surface of the material the cord 37 is withdrawn until the first surface 11 provided on the first element 3 contacts the inside surface of the material. At this stage the first element 3 may be in any position relative to the hole. To ensure that a seal can be made between the first element 3 and the material the first element 3 must be rotated so that the ridges 13,15 encircle the hole. It is preferable for the first element 3 to be aligned such that its longitudinal axis, shown as Y-Y in Figure 2, is generally parallel to the maximum length dimension of the hole. In this way, it can be ensured that the ridges encircle the hole. Whilst maintaining tension in the cord the user can rotate the first element 3 into position using his other hand. As the first element 3 is largely obscured by the material, the flats 25 provided on the stud 7 are used as alignment means.

The flats 25 are aligned parallel to the maximum length dimension of the hole.

Once the first element 3 has been aligned the apparatus 1 can be fixed to the material as described above in reference to attachment of the apparatus 1 to a material that has both sides accessible. To help to ensure that the apparatus 1 does not become misaligned during the fixing procedure the user should maintain tension in the cord 37.

The non-circular form of the elements and the interaction of the co-operating faces further aid in preventing rotation of the elements 3,5.

In the first embodiment, the cord 37 is threaded through a hole 39 provided in the stud 7. The cord 37 may be secured to the first element 3 in any suitable manner.

Typically a knot, of larger diameter than the hole 39, is tied in the end of the cord 37 adjacent to the outside surface of the first element 3. At the other end the cord 37, may be provided with a toggle 41. The toggle 41 also has a central hole and may also be secured to the cord 37 with a knot. In addition to providing a grip for a user, the toggle 41 serves to retain together all of the components of the sealing apparatus 1 as the diameter of the toggle 41 is chosen such that it will not pass through the various holes in the components.

In the embodiment shown in Figure 5, it is intended that the cord 37 and toggle 41 remain attached to the sealing apparatus 1 when it is in place sealing a hole, so that the cord 15 and toggle 41 can be used to assist with removal of the sealing apparatus 1 if necessary. It is envisaged that alternatively the cord 37 may be constructed in such a manner that it can be broken away or detached from the sealing apparatus 1 if required.

The second embodiment of the mechanical sealing apparatus 100, shown in Figure 6, is generally similar to the apparatus 1, having a first element 103, a second element 105, a means to fix the first element to the second element (not shown), and first and second co-operating surfaces 111,121.

The first and second elements 103,105 have domed cross- sectional profiles and are hollow to provide a space within the apparatus to contain any excess material that may otherwise inhibit the formation of a seal around the perimeter of the apparatus 100. The elements are each

provided with an internal reinforcing rib 135 and an external reinforcing rib 143 to increase their rigidity.

The second element is provided with an aperture 117 in the form of a truncated circle, having two opposed flat sides 119. As shown in Figure 7, the second element 105 is provided with a recess 145. This enables the stud (not shown) attached to the first element 103 to be shortened in length whilst maintaining the necessary thread length to ensure that the first and second elements 103,105 may be securely fixed together. A shorter stud facilitates more readily insertion of the first element 103 through the hole to be sealed.

The skilled reader will realise that a number of modifications or variations to the precise details described herein may be made without departing from the scope of the claims. For example, the apparatus may be provided with a fixing means that is offset from the medial position of the apparatus. Alternatively, the apparatus may be provided with two or more separate fixing means. It will also be appreciated that the apparatus described herein is also suitable for sealing pre-formed holes or openings.