ATTACHMENT SYSTEM

The present invention relates to attachment devices, such as screws which include a security device to inhibit or prevent removal of the attachment device when it is in place performing an attachment function.

There are many instances when attachments are performed and the security of the attachment is important to resist, deter or prevent vandalism or theft. One such situation is to prevent the theft of vehicle number plates. This invention therefore relates to a screw fixing, which is particularly suitable for use in preventing vandalism and theft and in particular the theft of vehicle registration plates. Other uses are also envisaged, particularly those where secure and 'tamper proof screw fixing is required.

The number of vehicles on the road is continually rising. Governments are trying to counter this rise by introducing penalties. Schemes such as high fuel pricing, parking restrictions, speed cameras and congestion charges are all designed to penalize users. All of these methods rely on the recognition of the vehicle by their registration plates, and hence there has been a rise in the theft of vehicle registration plates.

Other applications where protection against vandalism or theft is required are in advertising hoardings in public places for example road side, bus shelters, rail stations, airports, shops including shopping centers, garages and the like. External fittings such as cameras (CCTV), alarm systems and decorative materials to buildings, homes, offices, mobile homes, caravans, vehicles also have attachments which must be secure. Meters such as gas, electricity and water meters and cash tills, franking machines and automatic transaction machines also have attachments where it is important to prevent tampering and theft.

Similarly street furniture, public notices, street lighting, road signs, medical devices all have a need to prevent damage through tampering, vandalism and theft.

In addition to the need for protection against vandalism and theft there are situations in which attachments must be protected from removal in the interests of safety. For example the safety of electrical fixtures and devices, gas fixtures, provision for the

security of toxic or corrosive substances in both domestic and industrial environments all rely on attachments and there remains a need to increase the security and reliability of the attachment. Additionally there is a need for increased safety for childrens toys such as axle fixings for cleats for go carts.

Attachment devices have been proposed which contain security devices to render them difficult to undo. For example pop-rivets can be provided which are demountable only by drilling. These however are difficult to apply. European Patent Application 0463751 A relates to another form of security device by providing locking bolt assemblies which comprise a locking bolt assembly which prevents the release of loose parts in the event of bolt failure by use of a bolt having a head and a threaded main body with a central bore through the head and the main body portion in which the central bore has a necked down portion adjacent the end of the main body remote from the head. A plurality of slots are provided along the end of the main body portion in communication with the central bore which form bolt fingers around the necked down portion. A plunger is slidably received in the central bore and exerts radial pressure at the necked down portion to expand the bolt fingers outwardly and lock the bolt in its installed position without changing the preload of the installed bolt.

EP 0463751 A also makes the following references to other locking bolt assemblies

"Patent Specification US-A-3 042 094 which discloses an expander received inside a bolt to cause locking of the threads with the nut.

Patent Specification US-A-2 438 533 which discloses the use of a pin to spread two arms of a stud apart to lock the stud in place.

Patent Specification US-A-1 409 817 which discloses the use of a locking key that causes a slotted end of the bolt to expand and lock with a nut. Separated portions of the key are bendable to prevent separation of the key and bolt while the key head is received in a recess in the bolt head.

Patent Specifications US-A-2 871 749; US-A-2 463 859; US-A-322 657 and

FR-A-867 253 which all disclose locking members that are threaded into the bore through the centre of the bolt.

These systems all involve a pin device that is inserted after the screw attachment has been made to secure the attachment, however they suffer from the disadvantage that the pin is accessible and can be forcibly removed.

The present invention therefore provides an attachment device which provides an additional degree of security against dismantling of the attachment.

Accordingly the present invention therefore provides an attachment system comprising

i) a hollow screw threaded member having a head and an end opposite the head and provided with a bore extending therethrough wherein the walls of said bore adjacent said end are flexible and the cross section of the bore at the head is greater than the cross section at the end, and ii) a locking pin having an end that is insertable into the bore at the head and has a cross section greater than the cross section of the bore at the end of the bore in its unflexed state and the flexibility of the walls of the bore at the end of the screw threaded member is such that it allows the end of the locking pin to be forced through the end of the bore.

Accordingly in creating an attachment employing the attachment system of the present invention the initial attachment will first be formed by means of the screw threaded member attaching an article to another article, for example a vehicle registration plate to a vehicle, a protective plate to a meter, a security plate to an electrical device and the like, perhaps by mating with a nut. The attachment will then be secured by driving the locking pin through the bore of the screw threaded member so that the driving force expands the flexible end of the bore and the end of the locking device is forced beyond the end of the bore. Once the end of the locking device is through the end of the bore of the screw threaded member the flexibility of the walls of the bore at the end of the screw threaded member will bring the member into close proximity and preferably a gripping arrangement with the barrel of the locking member. In this way it will not be possible to withdraw the locking pin out of the bore of the screw threaded member because the end

of the locking pin that protrudes beyond the bore of the screw threaded member is of greater cross section that the end of the bore of the screw threaded member in its unflexed state.

The system of the present invention has the benefit that the locking pin is not fixed to the hollow screw threaded member and in the event of an attempt to remove the locking member by drilling the member will rotate with the drill thus inhibiting removal which can increase the time to effect vandalism or theft and increase the likelihood of detection and prevention.

The flexibility in the end of the screw threaded member can be provided in any suitable manner, we prefer however that it be provided by the provision of slots around the perimeter of the end of the bore of the screw threaded member.

In a further preferred embodiment the locking pin is provided with an element of increased cross section at the end that passes through the bore of the screw threaded member. The element of increased cross section is preferably shaped so that after it has passed through the flexible end of the screw threaded bore it provides a protrusion which bears against the extremity of the screw threaded bore preventing the protrusion from re-entering the bore in a backwards direction. A bulbous protrusion provided at the end of the pin may be provided with a flat rim at the surface of the protrusion adjacent to the end of the screw threaded bore after the protrusion has passed therethrough is particularly suitable.

In a preferred embodiment of the present invention the locking pin is designed so that the means whereby the screw threaded member is operated to provide the initial attachment is hidden by the insertion of the locking pin. This provides an additional security element in that it inhibits access to enable removal of the screw threaded member. For example the head of the screw threaded member maybe provided with a recess designed for the receipt of a key such as an Allen key to enable rotation of the screw threaded member to perform the attachment. The locking pin can then be provided with a head that conforms to the shape and/or size of the recess and lies within the recess when in the locking position thus preventing access to the attachment mechanism of the screw threaded member. The locking action due to the interaction of

the remote end of the screw threaded member and the locking pin will prevent access to the attachment mechanism of the screw threaded member thus preventing removal of the locking pin which provides additional security.

As indicated the attachment system of the present invention has wide ranging applications. It may be used in domestic and industrial situations and can be used to provide additional security and/or safety in a range of situations from light to heavy industry, service industries, transport, advertising any many others. The size and shape of the screw threaded member and the locking pin and the materials from which they are made will depend upon the use to which the system is to be put. The applications can range from small screws to secure registration vehicle number plates to vehicles to locking bolts in heavy industry. Accordingly the degree of flexibility required in the screw threaded member and the manner in which it is provided will vary from application to application. The head of the locking pin may be coloured in order to indicate that the security systems are in place which may be particularly useful in applications where inspection is required such as with franking machines, meter protection and other industrial environments.

In one embodiment the present invention relates to a theft resistant screw assembly suitable for use in securing registration plates to motor vehicles to prevent the easy removal and theft of vehicle registration plates. In this instance the fixing screw is preferably made from plastic, and the locking pin is preferably made from metal, but this could be reversed.

In this embodiment the invention suitably consists of two elements, the fixing screw (part 1) and the locking pin (part 2). The fixing screw is suitably used to secure the plate to the vehicle, and the locking pin is then inserted into it to prevent its removal so that the theft resistant screw assembly consists of a screwed method of attaching the registration plate to the vehicle, and a locking pin, which prevents access to the tightening/loosening arrangement of the screw.

Suitably, the theft resistant screw assembly contains interference features, which prevent the removal of the screw with the locking pin in position.

Suitably, the theft resistant screw assembly contains interference features, which prevent the removal of the locking pin after insertion into the screw.

Suitably, the theft resistant screw assembly consists of two or more elements.

In a preferred embodiment, the screw assembly of the present invention comprises

a) a screw body defining an external thread, said screw body having a central through hole provided thereto, wherein the screw body defines a screw thread provided with screw tightening means at a first end thereof and one or more slots at a second end thereof; and b) a locking pin arranged for receipt by said central through hole, wherein said pin defines a pin head at a head end thereof and a bulbous portion distal from said head end,

wherein said slots enable initial flexing of the second end of the screw body in response to receipt of the bulbous portion and subsequent deflexing thereof as the bulbous portion passes beyond the second end of the screw body to a pin lock position, and wherein in said pin lock position the pin head obscures the screw tightening means such as to prevent access thereto.

Suitably in the screw assembly, the screw tightening means is provided at a recessed position within said screw body.

Suitably, said recessed position defines part of said central through hole.

In an additional embodiment of the present invention where the attachment is performed by the screw threaded member engaging with a nut the cross section and flexibility of the end of the screw threaded member are such that the extremity of the end passes through the nut while a section close to the end will engage with the nut. The locking pin is designed so that it will pass through the bore of the screw threaded member and by virtue of the flexibility of the end of the screw threaded member will increase the external diameter of the end of the screw threaded member beyond the nut so that it cannot be removed by passing back through the nut.

The present invention is illustrated in relation to securing a vehicle registration plate by reference to the accompanying drawings in which:

Figure 1 shows the external form of the fixing screw. Figure 2 shows the method of tightening the fixing screw. Figure 3 shows a section of the fixing screw. Figure 4 shows the external form of the locking pin. Figure 5 shows a section of the fixing screw and locking pin assembled.

The fixing screw has an external thread to achieve an attachment such as connecting a registration plate to the vehicle via a nut or similar (1a).

The fixing screw has an internal method of tightening e.g. slot, hexagon or other form of screw tightening means perhaps by use of an Allen key, which is suitably recessed (1b).

The fixing screw has a central tapered through hole (1c) and one or more slots (1d) which allow the screw to flex. The central tapered through hole and the external form of the locking pin (2a) have a similar profile.

The locking features (1e) on the fixing screw are of sufficient size to allow it to be inserted into the nut (or similar) when the screw flexes inwardly to pass through the nut, but are also of sufficient size to prevent the nut being removed when the locking pin is inserted, which prevents flexing.

The area (1f) is of sufficient diameter and length that the nut (or similar) is free to rotate on it.

The locking pin has a feature (2b), which is of sufficient size to allow the pin to be inserted into the fixing screw, but which is also of sufficient size to prevent removal of the pin after insertion.

The head of the locking pin (2c) is of sufficient size to allow insertion into the locking screw, but prevent access to the tightening arrangement.

In one use aspect, the item to be attached is first attached to the vehicle using the fixing screw (1) and tightened. When secure, the locking pin (2) is inserted into the through hole in the fixing screw, which locks into position preventing access to the method of removing said screw. If the fixing screw is loosened without removing the locking pin, the locking features (1e) prevent the nut (or similar) being removed from the locking screw.

As previously described the attachment systems of the present invention have an extremely wide range of uses from lightweight screw attachment systems to heavy duty industrial attachment systems. The invention has use in all the outlets previously described although the outlets envisaged are not limiting on the potential uses of the present invention.

The invention is also concerned with the manner in which the attachment systems are provided. For example the screw threaded member and the locking pin may be provided as a kit, they may be provided as a multi kit package of several attachment systems, alternatively they may be provided as part of a multi component package including the article which is to be attached. For example the appropriate number of attachment systems of the present invention may be supplied together with the article to be attached such as a vehicle registration plate. The invention therefore includes any such kits and any such means of supplying the attachment system of this invention.