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Patent Searching and Data


Title:
ANTI-THEFT DEVICE
Document Type and Number:
WIPO Patent Application WO/2017/103602
Kind Code:
A1
Abstract:
A vehicle drain plug anti-theft device, comprises a support portion for attaching to a head portion of a vehicle drain plug; a sleeve mountable to the support portion such that the sleeve is rotatable relative to the support portion and such that, in use, the sleeve covers the head portion of the vehicle drain plug to prevent access to said head portion of the vehicle drain plug; and a retaining portion configured to substantially prevent separation of the support portion and the sleeve.

Inventors:
ROSE MATTHEW (GB)
WHOLEY RYAN (GB)
FORSTER RICHARD (GB)
CROFT LAWRENCE (GB)
Application Number:
PCT/GB2016/053956
Publication Date:
June 22, 2017
Filing Date:
December 16, 2016
Export Citation:
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Assignee:
TISS LTD (GB)
International Classes:
B60K15/03; F01M11/04
Domestic Patent References:
WO2010025476A12010-03-04
Foreign References:
CN2047648U1989-11-15
CN2929302Y2007-08-01
Attorney, Agent or Firm:
MARKS & CLERK LLP (GB)
Download PDF:
Claims:
CLAIMS:

1. A vehicle drain plug anti-theft device, comprising:

a support portion for attaching to a head portion of a vehicle drain plug;

a sleeve mountable to the support portion such that the sleeve is rotatable relative to the support portion and such that, in use, the sleeve covers the head portion of the vehicle drain plug to prevent access to said head portion of the vehicle drain plug; and

a retaining portion configured to substantially prevent separation of the support portion and the sleeve.

2. An anti-theft device according to claim 1 , wherein the support portion comprises a fixing configured to secure the support portion to the drain plug. 3. An anti-theft device according to claim 1 or claim 2, wherein the sleeve is mountable to the support portion such that the sleeve covers the support portion.

4. An anti-theft device according to claim 2 or claim 3, wherein the sleeve is movable relative to the support portion between a closed configuration in which access to the fixing is prevented and an open position in which access to the fixing is permitted.

5. An anti-theft device according to any preceding claim, wherein the sleeve is formed of a generally hollow cylinder comprising a circumferential wall and a base.

6. An anti-theft device according to any preceding claim, wherein the sleeve is configured to circumferentially surround the support portion so as to substantially prevent access to the support portion and a head portion of the drain plug. 7. An anti-theft device according to claim 6, wherein a portion of the sleeve which circumferentially surrounds the support portion defines a generally tapered outer surface.

8. An anti-theft device according to claim 2 or any claim dependent on claim 2, wherein the sleeve comprises an aperture configured to permit access to the fixing.

9. An anti-theft device according to any of claims 2-7, wherein the sleeve comprises an initial pilot hole configured to provide a location for a subsequent aperture configured to permit access to the fixing. 10. An anti-theft device according to claim 2 or any claim dependent on claim 2, wherein the fixing is a threaded fixing and wherein the support portion comprises a correspondingly threaded hole configured to receive the threaded fixing.

1 1. An anti-theft device according to any preceding claim, wherein the support portion comprises an inner wall having a first surface which has a complementary cross-sectional profile to that of a second surface of an outer face of a head portion of a drain plug to which the support portion is configured to be attached.

12. An anti-theft device according to claim 1 1 , wherein the first surface of the inner wall of the support portion is configured to contact the second surface of the outer face of the head portion of the drain plug so as to substantially prevent relative rotation between the support portion and the drain plug.

13. An anti-theft device according to claim 10 or claim 1 1 wherein the cross- sectional profile of the first surface of the inner wall is that of a regular polygon.

14. An anti-theft device according to any preceding claim wherein the retaining portion comprises a first generally annular groove in the support portion. 15. An anti-theft device according to claim 14, wherein the first annular groove is located in an outer face of the support member.

16. An anti-theft device according to any preceding claim wherein the retaining portion comprises a second generally annular groove in the sleeve.

17. An anti-theft device according to claim 16 when dependent on either claim 15 or claim 14, wherein the retaining portion comprises a retainer; and wherein the first and second generally annular grooves are configured to receive the retainer, such that, in use, the retainer is located within both the first generally annular groove and the second generally annular groove. An anti-theft device according to claim 17, wherein the retainer takes the form

19. An anti-theft device according to claim 2 or any claim dependent on claim 2, wherein the fixing is configured to urge against a head portion of the drain plug so as to axially fix the support portion relative to the drain plug.

20. An anti-theft device according to any preceding claim, wherein, in use, rotation of the sleeve relative to the support portion does not result in rotation of the drain plug.

21 . A method of securing a vehicle drain plug using an anti-theft device, the anti- theft device comprising a support portion, a sleeve, and a retaining portion; the method comprising:

attaching the support portion to a head portion of a vehicle drain plug;

mounting the sleeve to the support portion such that the sleeve is rotatable relative to the support portion and such that, in use, the sleeve covers the head portion of the vehicle drain plug to prevent access to said head portion of the vehicle drain plug; and the retaining portion substantially preventing separation of the support portion and the sleeve.

22. A vehicle drain plug anti-theft device substantially as hereinbefore described having reference to the figures.

Description:
Anti-theft Device

The present invention relates to a vehicle drain plug anti-theft device, and in particular to a fuel tank drain plug anti-theft device.

A vehicle generally includes many receptacles for various fluids used by the vehicle. Such fluids include, but are not limited to, oil, water, anti-freeze, brake fluid, transmission fluid, power steering fluid, additives, fluid for a Selective Catalytic Reduction system and fuel (e.g. petrol, diesel, ethanol etc.). Fuel is typically stored within a fuel tank of the vehicle. Such fuels are valuable and therefore it is desirable to prevent fuel theft from vehicles, particularly in the case of commercial road vehicles.

One known method of stealing fuel from vehicles is to siphon fuel from the fuel tank via a fuel tank inlet disposed in the side of the vehicle. It is conventional to fit vehicles with a lockable fuel tank filler cap to prevent unauthorised access to the fuel tank inlet. However, since the fuel filler cap is accessible it is vulnerable to tampering and can often be forced open by the determined thief. In addition, it is not always practical to fit a vehicle with a lockable fuel filler cap. Anti-siphon devices, such as that described in PCT/GB2007/001 126 filed by the present applicant, exist to prevent such siphoning. Such anti-siphon devices typically comprise some form of structure to prevent insertion of a siphon tube into the tank via the fuel tank inlet.

In addition to a fuel inlet, many vehicle fuel tanks further comprise a fuel drain configured to empty fuel from the fuel tank when required, such as during maintenance of the vehicle. Such fuel drains typically comprise a drain plug configured to block the fuel drain so that fuel is retained in the fuel tank during normal use. As such, another known method of stealing fuel from a vehicle is to simply remove the drain plug of the vehicle in order to cause any fuel contained in the fuel tank to empty. It will be appreciated that even by unscrewing the drain plug by a small amount (i.e. not fully removing the drain plug), it may be possible to release fuel from the fuel tank so that it can be stolen.

It is an object of the present invention to obviate or mitigate at the above described problems. It is a further object of the present invention to provide an improved or alternative vehicle drain plug anti-theft device. According to a first aspect of the present invention there is provided a vehicle drain plug anti-theft device, comprising a support portion for attaching to a head portion of a vehicle drain plug; a sleeve mountable to the support portion such that the sleeve is rotatable relative to the support portion and such that, in use, the sleeve covers the head portion of the vehicle drain plug to prevent access to said head portion of the vehicle drain plug; and a retaining portion configured to substantially prevent separation of the support portion and the sleeve.

Vehicle drain plugs, such as the drain plug for a vehicle fuel tank, are typically attached (for example to a fuel tank) via a threaded portion of the drain plug. As such the drain plug may be removed from the fuel tank by rotating the drain plug. In particular, it is common to rotate the drain plug using a head portion of the drain plug. The head portion may include an engagement feature (e.g. a hexagonal wall, a plain slot, a Phillips drive feature, a Pozidriv drive feature, etc.) which is configured to interact with a tool in order to provide rotation of the drain plug. The anti-theft device provides the advantage that access to this feature is substantially prevented, thus hindering any attempt to rotate the drain plug. The anti-theft device further provides the advantage that because the sleeve is rotationally moveable relative to the support portion; rotation of the sleeve does not produce rotation of the support portion or the drain plug, thus preventing removal of the drain plug by rotating the sleeve.

The sleeve may rotatable relative to the support portion such that the axis of rotation of the sleeve is substantially the same as an axis of rotation of the drain plug, said rotation enabling removal of the drain plug.

It will be appreciated that by "for attaching to" it is meant that the support portion is a separate entity to the vehicle drain plug. That is to say, the support portion and the vehicle drain plug are formed as separate pieces which are configurable from an unattached state to an attached state relative to one another. So as to permit assembly of the support portion and the head portion of the vehicle drain plug, the support portion may define an engagement feature configured to engage the head portion of the vehicle drain plug. In particular, the engagement portion may be a socket region configured to receive the head portion of the vehicle drain plug. That is to say, the support portion may comprise a socket region configured to receive the head portion of the vehicle drain plug. The support portion may comprise a fixing configured to secure the support portion to the drain plug. Alternatively, the support portion may be attached to the head portion of a vehicle drain plug in any appropriate manner - e.g. welding, adhesive or the like. The fixing may be a threaded fixing. The support portion may comprise a correspondingly threaded hole configured to receive a threaded fixing.

The sleeve may be mountable to the support portion such that the sleeve covers the support portion. Because the sleeve covers the support portion, the sleeve may prevent access to the support portion in order to prevent rotation of the support portion by a user or a tool, thus preventing rotation/removal of the vehicle drain plug.

The sleeve may be movable relative to the support portion between a closed configuration in which access to the fixing is prevented and an open position in which access to the fixing is permitted. By allowing access to the fixing the drain plug can be installed or removed. The existence of a closed position provides further security and/or may prevent the fixing from being exposed to dirt etc. By preventing the fixing from being exposed to dirt it may prevent the fixing from being clogged with dirt, thereby impeding removal of the fixing by a user who is authorised to do so. The sleeve may be formed of a generally hollow cylinder comprising a circumferential wall and a base. In other embodiments the sleeve may have any appropriate shape and take any appropriate form.

The sleeve may be configured to circumferentially surround the support portion so as to substantially prevent access to the support portion and a head portion of the drain plug. As previously discussed, this ensures rotation of the support portion is prevented by the presence of the sleeve.

A portion of the sleeve which circumferentially surrounds the support portion may define a generally tapered outer surface. The generally tapered outer surface may be generally frusto-conical or domed. The tapered outer surface may taper such that the portion of the sleeve tapers radially inwards towards the base of the sleeve.

The sleeve may comprise an aperture configured to permit access to the fixing.

The sleeve may comprise a pilot hole configured to provide a location for an aperture configured to permit access to the fixing. The sleeve may comprise an initial pilot hole configured to provide a basis for a subsequent aperture configured to permit access to the fixing. The pilot hole may be a blind hole. The pilot hole may be of lesser diameter than the aperture such that the aperture may provide access to the fixing for a tool for operating the fixing, whereas the pilot hole may not provide access to the fixing for said tool for operating the fixing. Operating the fixing may include releasing the fixing, for example, by unscrewing the fixing.

The conduit may be located in a circumferential wall and/or in a base of the sleeve. The conduit may extend radially (with respect to the axis of rotation of the sleeve/drain plug). The conduit may be configured to receive a tool, such as a screwdriver. The tool may be used to operate the fixing.

The support portion may comprise an inner wall having a first surface which has a complementary cross-sectional profile to that of a second surface of an outer face of a head portion of a drain plug to which the support portion is configured to be attached. The cross-sectional profile may be the profile of a cross-section in a plane substantially perpendicular to an axis of rotation of the drain plug and/or sleeve. For example, the head portion of the drain plug may have an outer wall surface that has a generally hexagonal cross-sectional profile and the inner wall surface of the support portion may have a cross-sectional profile which is a similarly sized and shaped hexagon, albeit, slightly oversized such that the head portion of the drain plug can be received by the support portion.

The first surface of the inner wall of the support portion may be configured to contact the second surface of the outer face of the head portion of the drain plug so as to substantially prevent relative rotation between the support portion and the drain plug.

The cross-sectional profile of the first surface of the inner wall may be that of a regular polygon. E.g., hexagon, pentagon, octagon etc. In other embodiments the cross- sectional profile may be a rotationally symmetric shape of order 2 or above.

The retaining portion may comprise a first generally annular groove in the support portion. The first annular groove may be located in an outer face of the support member.

The retaining portion may comprise a second generally annular groove in the sleeve. The retaining portion may comprise a retainer. The first and second generally annular grooves may be configured to receive the retainer, such that, in use, the retainer is located within both the first generally annular groove and the second generally annular groove. In this way separation of the sleeve and the support portion in an axial direction is substantially prevented, however, in other embodiments, any other method of preventing separation of the support member and sleeve may be used.

The retainer may take the form of a ring such as piston ring or a snap ring.

The fixing may be configured to urge against a head portion of the drain plug so as to fix the support portion relative to the drain plug. The fixing may be configured to urge against a head portion of the drain plug so as to axially fix the support portion relative to the drain plug. The fixing may be configured to urge against a head portion of the drain plug so as to rotationally fix the support portion relative to the drain plug.

In use, rotation of the sleeve relative to the support portion may not result in rotation of the drain plug. According to a second aspect of the invention there is provided a method of securing a vehicle drain plug using an anti-theft device, the anti-theft device comprising a support portion, a sleeve, and a retaining portion; the method comprising: attaching the support portion to a head portion of a vehicle drain plug; mounting the sleeve to the support portion such that the sleeve is rotatable relative to the support portion and such that, in use, the sleeve covers the head portion of the vehicle drain plug to prevent access to said head portion of the vehicle drain plug; and the retaining portion substantially preventing separation of the support portion and the sleeve.

It will be appreciated that by "attaching" it is meant that the support portion and the vehicle drain plug are separate pieces configurable from an unattached state to an attached state relative to one another.

It will be appreciated that any of the optional features set out above in relation to the first aspect of the present invention may equally be applied to the method of the second aspect of the invention. Specific embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a cross-sectional view of a support portion of an anti-theft device according to the present invention;

Figure 2 is an isometric view of a support portion of an anti-theft device according to the present invention; Figure 3 is a cross-sectional view of a sleeve of an anti-theft device according to the present invention;

Figure 4 is an enlarged schematic cross-sectional view of a portion of an anti-theft device according to the present invention;

Figure 5 is a schematic cross-sectional view of an anti-theft device according to the present invention; and

Figure 6 is a cross-sectional view of a sleeve of an anti-theft device according to another embodiment the present invention.

Drain plugs are typically secured to a fuel tank via a screw portion of the drain plug which is received by a correspondingly threaded orifice of the fuel tank. As such, in order to remove the drain plug, a potential thief is required to rotate the drain plug. The present invention therefore seeks to prevent or hinder rotation of the drain plug by a thief, thus preventing removal of the drain plug from the fuel tank and hence the theft of the fuel. Because the nature of theft is often opportunistic, hindering rotation of the drain plug (as opposed to complete prevention of said rotation) may be sufficient to prevent fuel theft.

Figures 1 and 2 show cross-sectional and isometric views respectively of a support portion 100 of an anti-theft device according to the present invention. The support portion 100 comprises a body portion 101 formed as a generally hollow cylinder composed of a generally rigid material such as for example a plastic or a metal. The support portion 100 comprises a plurality of inner walls 102 arranged to define a socket region configured to receive a head portion of a drain plug of a vehicle fuel tank. Fillets 103 are disposed between the inner walls 102 of the socket region so as to reduce corner stresses between the walls 102. The inner walls 102 of the present embodiment are arranged such that the socket region defines a generally hexagonal cross-section for use with a correspondingly hexagonal head portion of the drain plug. During use, when the head portion of the drain plug is received by the socket region, each of the inner walls 102 may contact an outer face of the drain plug head portion such that rotational movement of the support portion relative to the drain plug is substantially prevented. That is to say, during use, the socket region rotationally couples (such that there is substantially no relative rotation therebetween) the drain plug to the support portion. Although the socket region described above is generally hexagonal, it will be appreciated that the inner walls 102 may define a socket region having a different cross section. For example, the inner walls 102 may be arranged to form another regular polygon or a spline configured to receive a corresponding regular polygon or spline portion of a drain plug. Alternatively, the support portion 100 may comprise a single inner wall 102 arranged to form a generally cylindrical socket region configured to receive a head portion of a drain plug. In some cases the head portion may be correspondingly cylindrical to the generally cylindrical socket region.

The support portion 100 further comprises a plurality of (in this particular case, three) generally-cylindrical holes 104 extending radially outwards from the inner walls 102 of the socket region to a generally cylindrical outer face 105 of the support portion 100. Each of the three holes 104 is centrally located on alternate inner walls 102 of the socket portion. It will be appreciated that alternative embodiments of the invention may comprise a different number of and/or a different location of the holes 104. For example, if the support portion includes this type of fixing (discussed in more detail below) the support portion 100 may comprise one, two or more than three holes 104.

Each of the holes is configured to receive a fixing (not shown), typically in the form of a threaded fixing, for example, a screw, such as a grub screw. The holes 104 are threaded to receive the screws. During use, when the head portion of the drain plug is received by the socket region of the support portion 100, each fixing is urged against the head portion drain plug to secure the support portion 100 to the drain plug. As such, relative movement between the support portion 100 and the drain plug is substantially prevented. That is to say, the fixings prevent axial separation of the support portion 100 and the drain plug. The outer face 105 defines an outer diameter and comprises a first annular groove 106. A generally C-shaped retainer 107, which may be a ring such as a piston ring or a snap ring, surrounds the support portion 100 within the annular groove 106. With further reference to Figure 4, the retainer 107 defines a width W1 which is narrower than a width W2 of the first annular groove 106. The retainer 107 defines a depth D1 between an outer diameter and an inner diameter of the retainer 107. The retainer 107 is sized such that the outer diameter of the retainer 107 is larger than the diameter of the outer face 105 and the inner diameter of the retainer 107 is smaller than the diameter of the outer face 105. As such, the retainer 107 is partially located within the first annular groove 106 and partially located outside of it.

The first annular groove 106 defines a depth D2 and an inner diameter that is smaller than the inner diameter of the retainer 107. The retainer 107 is therefore constrained by the first annular groove 106 such that rotational movement of the retainer 107 within the first annular groove 106 is permitted. However axial movement of the retainer 107 is substantially limited by the groove 106 and therefore axial separation of the retainer 107 and the support portion 100 is prevented.

With reference to Figures 3 and 4, the support portion 100 is received by a sleeve 200 comprising a generally annular surround (or generally circumferential portion) 201 configured to circumferentially receive the support portion 100. The surround 201 is capped by a base 205 so as to substantially prevent access to the support portion and an end of the drain plug from outside of the anti-theft device. The sleeve 200 is composed of a generally rigid material, such as a plastic or a metal. The surround 201 defines an inner diameter which is larger than the diameter of the outer face 105 of the support portion 100, such that the support portion 100 is moveable within a region bounded by the surround 201 . The surround 201 defines a second annular groove 202 configured to receive the retainer 107. The first annular groove 106 defines a depth D3 that is smaller than the depth D1 of the retainer 107. As such, when the retainer 107 is received by the second annular groove 202, the retainer 107 is partially located within the second annular groove 202 and partially located within the first annular groove 106. When a user attempts to separate the support portion 100 and the sleeve 200 by pulling on the sleeve 200 in an axial direction, the retainer 107 acts to prevent separation of the support portion 100 and the sleeve 200 because the retainer 107 is simultaneously constrained by both the first annular groove 106 and the second annular groove 202. The retainer 107 is composed of a resiliently deformable material configured to urge against the second annular groove 202 in a radially outward direction. When support portion 100 and the sleeve 200 are assembled, the retainer 107 circumferentially contacts the second annular groove 202 to hold the retainer 107 against the sleeve 200. Because the retainer 107 is rotationally moveable relative to the support portion 100, the sleeve 200 is therefore also rotationally moveable relative to the support portion 100. During use, when a drain plug is received within the socket region of the support portion 100, rotation of the sleeve 200 will not produce rotational movement of the support portion 100. As such, the anti-theft device not only prevents and/or hinders access to the drain plug, but also prevents a potential thief from trying to remove the drain plug by rotating the sleeve portion of the anti-theft device.

In the present embodiment, it may be said that the first annular groove 106, the second annular groove 202 and the retainer 107 constitute a retaining portion of the anti-theft device. It will be understood that the primary purpose of the retaining portion is to allow rotational movement between the support portion 100 and the sleeve 200 whilst at the same time substantially limiting axial movement between the support portion 100 and the sleeve 200 and/or substantially preventing separation of the support portion 100 and the sleeve 200. Although the anti-theft device of the present invention described above comprises a retainer 107 which is separate to the support portion 100, it will be appreciated that in alternative embodiments of the anti-theft device the retaining portion may take any appropriate form. For example, the retainer may be integrally formed as part of the support portion. For example, the retainer may be formed as a radially extending lip of the support portion. The radially extending lip may be received by a groove of the sleeve configured to permit rotational movement between the support portion and the sleeve and further configured to substantially prevent axial separation of the support portion and the sleeve. Alternatively, the retainer may be formed as a radially extending lip of the sleeve. The radially extending lip may be received by a groove of the support portion configured to permit rotational movement between the support portion and the sleeve and further configured to substantially prevent axial separation of the support portion and the sleeve. It will be appreciated that it may be possible to manufacture such arrangements using additive manufacturing techniques.

With reference to Figure 5, during use, the annular portion 201 substantially covers the support portion 100 so as to prevent access to the support portion 100. In particular, the support portion 100 defines an axial width W3 which is smaller than an axial depth W4 of the sleeve 200 which is the depth of the region bounded by the annular surround 201 within which the support portion 100 is received. The first and second annular grooves 106, 202 are respectively positioned such that during use, when the retaining member 107 is simultaneously received within both annular grooves 106, 202, an end face 108 of the support portion 100 is generally aligned with an end face 203 of the sleeve 200. It will be appreciated that some misalignment may exist between the end faces 108, 203 due to axial movement of the retaining member 107 within the first and second annular grooves 106, 202. However the amount or size of this misalignment will be small in relation to a tool which may be used to attempt to rotate the support portion 100 and so will not be sufficient to permit rotation of the support portion 100. Alternatively, the first and second annular grooves 106, 202 may be located, and the sleeve may be sized, such that the support portion 201 extends past the end face 108 of the support portion 100. As such, rotation of the support portion 100 by a thief or user is substantially prevented by the presence of the sleeve 200. The width W3 of the support portion 100 is sized such that the head portion of the drain plug is substantially covered by the support portion 100 when it is received within the socket region. That is to say, the anti-theft device is sized such that access to the features of the drain plug which facilitate a user rotating the drain plug (e.g. the sides of a hexagonal bolt head, etc.) is substantially prevented by the presence of the support portion 100. For example, where the drain plug comprises a generally hexagonal head portion, all six faces of the head portion are substantially received within the socket region of the support portion 100. That is to say, it is not possible for a tool configured to rotate the drain plug (e.g. a spanner) to access to the corresponding features of the drain plug configured to interact with that tool.

As is described above, vehicle drain plugs are typically secured to a fuel tank via a screw portion of the drain plug which is received by a threaded orifice of the fuel tank. As such, in order to remove the drain plug, a potential thief is required to rotate the drain plug. By using the anti-theft device of the present invention, the thief is unable to access the features of the drain plug which ordinarily permit its rotation. As such, the thief may attempt to rotate the drain plug by rotating the sleeve 200. However, as discussed above, because the sleeve 200 is rotationally moveable relative to the support portion 100 and the drain plug, any attempt by the thief to rotate the drain plug by rotating the sleeve 200 will be ineffective. Furthermore, the thief is unable to remove the anti-theft device by pulling on the sleeve 200, as the anti-theft device is secured to the drain plug via the fixings. With reference to Figures 1 -3, the sleeve 200 further comprises an aperture 204 configured to permit access to the holes 104 and fixings of the support portion 100. The aperture 204 is formed as a generally cylindrical hole within the annular surround 201 . In other embodiments the aperture may take any appropriate form. The aperture 204 extends in a generally radial direction and defines a diameter which is equal to or greater than a diameter of the holes 104. The aperture 204 is positioned such that during use the sleeve 200 is moveable (in this case, by rotation relative to the support portion) to a configuration in which the aperture 204 is substantially concentric to (or aligned with) one of the holes 104. The holes 104 of the support portion 100 are generally aligned with one another such that a longitudinal axis of each hole lies generally within the same plane as the longitudinal axes of the other holes. As such, the sleeve 200 is moveable to a plurality of positions in which the aperture 204 and one of the holes 104 are concentrically aligned. It will be appreciated that when the sleeve 200 is moved to a position in which the conduit 204 is not aligned with any of the holes 104, the surround 201 substantially prevents access to the holes 104 and fixings. This not only makes accessing the fixings more difficult, thereby improving the security of the device, but also may prevent dirt etc. from reaching the fixings and clogging them. Clogging of the fixings may make it more difficult to un-do the fixings at a time when an authorised user wants to remove the anti-theft device.

The fixings of the support portion are typically screws, such as grub screws, received within one of the holes 104 of the support portion 100. As such, when the conduit 204 is concentrically aligned with one of the holes 104, a user is able to insert a tool, such as a screwdriver (or alien key etc.), through the aperture 204 and into the hole 104 so as to tighten or loosen the fixing. It will be appreciated that once one of the fixings has been tightened or loosened, the tool may be removed from the hole 104 and the sleeve 200 (and hence the aperture 204) may rotated such that the aperture 204 is aligned with another of the holes 104 of the support portion 100. In this manner, the user may tighten or loosen each of the fixings individually. As such, the anti-theft device may be installed upon or removed from the drain plug by tightening or loosening each of the plurality of fixings. Furthermore, it will be appreciated that in this way the anti-theft device may be removed or installed in-situ, i.e. without removing the drain plug from the fuel tank of the vehicle. An alternative embodiment of the sleeve 200 is shown in Figure 6. The sleeve 200 of Figure 6 differs from the embodiment shown in Figure 3 in that the surround 201 comprises a tapered outer surface 207 that is inclined at a non-zero angle relative to a longitudinal axis of the sleeve 200. It will be understood that the longitudinal axis of the sleeve 200 is an axis parallel to an axis of rotation of the sleeve 200. As such, the outer surface 207 is generally frusto-conical in shape. It will be appreciated that due to the relative incline between the longitudinal axis of the sleeve 200 and the outer surface 207, the outer surface 207 is difficult to grip using traditional tools such as pliers. Such tools are commonly configured to grip cylindrical surfaces, and therefore are not suited to gripping the inclined surface 207.

In the embodiment shown in Figure 6 the outer surface 207 extends between a narrow diameter portion aligned with the base 205, and a wider diameter portion aligned with the end face 203. In other words, the tapered outer surface tapers such that the sleeve tapers radially inwards towards the base 205 of the sleeve. Alternatively, the direction of the chamfer may be reversed. That is, in alternative embodiments of the invention the outer surface 207 may comprise a wider diameter at the base 205 than at the end face 203 - i.e. such that the sleeve tapers radially outwards towards the base 205 of the sleeve. It will further be appreciated that the sleeve 200 may comprise a support 201 that is partially tapered. That is, whilst in the present embodiment the entire outer surface is tapered, in other embodiments only a portion of the outer surface may be tapered. For example, the support 201 may comprise a tapered surface and a cylindrical surface. The cylindrical surface and the tapered surface may meet midway between the end face 203 and the base 205. The cylindrical surface may have substantially the same diameter as the tapered surface at the point where the cylindrical surface and the tapered surface meet. Although the tapered surface in the present embodiment is frusto-conical, in other embodiments the tapered surface may have any appropriate tapered shape, for example, the tapered surface may be generally domed.

The sleeve 200 of Figure 6 also differs from the embodiment shown in Figure 3 in that the sleeve 200 comprises a pilot hole 208 formed as a generally hemispherical indentation of the outer surface 207. As such, in this case, the pilot hole is a blind hole that does not extend all the way through the sleeve. In other embodiments any appropriate blind hole may be used. The pilot hole 204 is configured to provide a location for an aperture 204 to be drilled through the support 201 . As such, the pilot hole 208 is positioned such that it is substantially aligned (axially) with the holes 104 of the support portion 100 when the sleeve 200 and the support portion 100 are assembled. In use, when the ant-theft device is installed upon a drain plug of a vehicle and a user wishes to remove the anti-theft device from the drain plug, the pilot hole 208 is drilled to form the aperture 204. Once drilled, the aperture 204 provides access to any fixings received within the holes 104.

Although the pilot hole 204 above is described as a generally hemispherical indentation of the outer surface 207, it will be appreciated that the pilot hole may instead be a through-hole of the surround 201 that passes through the surround 201 . Furthermore, in order to prevent access to the fixings by a tool configured to tighten or loosen the fixings, the pilot hole 204 may have a narrower diameter than a diameter of the tool. The larger diameter of the aperture (as compared to the pilot hole) may provide access to the fixing for a tool for operating the fixing, whereas the smaller diameter pilot hole (as compared to the aperture) may not provide access to the fixing for said tool for operating the fixing. Operating the fixing may include releasing the fixing, for example, by unscrewing the fixing, such that the tool may be a screwdriver, alien key or the like. It will be appreciated that during assembly of the anti-theft device, the support portion 100 may first be assembled upon a drain plug of a vehicle (without the sleeve 200). The fixings may be tightened using a tool, and then the sleeve 200 assembled upon the support portion 100 to substantially cover the support portion 100 and the drain plug. The sleeve 200 may be assembled upon the support portion 100 by press fitting or any other appropriate method. Once the sleeve 200 has been pressed upon the support portion 100, the retainer 107 substantially prevents separation of the support portion 100 and the sleeve 200. In an alternative assembly method the sleeve 200 may first be assembled upon the support portion 100 by press fitting or any other appropriate method. Once the sleeve 200 has been pressed upon the support portion 100, the retainer 107 substantially prevents separation of the support portion 100 and the sleeve 200. The support portion 100 and attached sleeve may then be assembled upon a drain plug of a vehicle. The fixings may then be tightened using a tool via the I aperture 204 in the sleeve.

It will be appreciated that an alternative embodiment of the invention may include a sleeve 200 having any appropriately shaped outer surface, for example the generally cylindrical outer surface such as that shown in Figure 3, and comprising any appropriate pilot hole, such as, for example, that shown in Figure 6. A further alternative embodiment of the invention may include a sleeve 200 having any appropriately shaped outer surface, such as an appropriate tapered surface portion, for example portion 207 shown in Figure 6, and any appropriate aperture, such as the aperture 204 shown in Figure 3. While embodiments of the invention have been described above, it will be appreciated that modifications can be made to those embodiments without departing scope of the present invention. In particular, although the anti-theft device has been described in relation to a fuel tank drain plug, it will be appreciated that the invention may be applied to any drain plug of a vehicle.

In the described embodiment a fixing in the form of three grub screws secures the support portion to the drain plug. In other embodiments any method of attaching the support portion to the vehicle drain plug may be used. For example, the support member may be welded or attached with adhesive to the drain plug.