BACKGROUND The problem to be solved is"that shipping container doors are easily opened by thieves possessing boltcutters or other padlock-destroying tools used to cut through sealing means such as padlocks and seals. There is a need to make such doors more secure." Other destructive tools include hammers and cold chisels capable of shearing bolt heads. Containers are often stored in isolated places and thieves know that containers often hold valuable items.

Containers employ a very commonly used design of sealing means, involving a pair of doors each having a number of rotatable locking bars held within brackets; locking handles on the locking bars can be rotated in order to engage with fixed locking hasps about the open end of the container. These are padlocked together so as to prevent rotation in the direction of opening in order to seal shipping containers, storage containers, and freight compartments on lorries, in particular long-distance lorries (another area liable to thefts or substitutions of goods as for smuggling).

Previous patent documents on this art have tended to describe complex electronic alarm devices, commonly using radio signals (US 5755126 to Lanigan) or the cellular telephone network (US 5615247 Mills) to arouse a security guard that security is in the process of being breached. US4688244 Hannon et al logs any such openings during a trip-although most burglaries occur either before a loaded container is collected from a consignor's premises or after it is delivered at a consignee's premises. An actual ship journey is relatively safe. Further, many containers never travel; they are simply used as overflow storage at warehouses or on building sites, far from any security guard. One problem with a radio link is that a listening system has to be operational at any container storage site, and many containers shipped through the Far East may be far from sophisticated protection of this type.

In all cases there is a possibility that a given container may hold millions of dollars worth of consumer electronics devices readily disposed of by a thief.

Less heavily technology based solutions include US 5509700 Kennedy Jr with a partially concealed and frangible handle so that a thief can only break the handle off, US6065314 to Nicholson which provides another lockable handle largely concealing the associated padlock, and US 5261258 to Bunger who describes an armour-protected latch bar and a shroud specifically designed for a disk padlock so that only the area about the tumbler is exposed and any damage to that area does not result in the shackle of the padlock becoming open. Lee (US 5924973) describes a complex lock which becomes more secure if the combination lock included is attacked.

All the prior art reviewed involves making modifications to the container doors, and often includes reliance on high technology. Furthermore, the real owner may also be left with an unopenable container if the thief has damaged the lock during an unsuc- cessful attempt at burglary.

OBJECT It is an object of this invention to provide an accessory for rendering a container door more secure, or at least to provide the public with a useful choice.

STATEMENT OF INVENTION In a first broad aspect this invention provides a security accessory, using a padlock having a shackle, for rendering a pair of lockable container-type doors more secure (the doors being of the type where each door has at least one locking rod parallel to a locking rod on the other door), characterized in that the security accessory includes a first rigid, elongated arm, a second rigid, elongated arm, and a shroud, each made of a material resistant to unauthorised interference; the shroud being capable of surrounding the padlock yet having a padlock access aperture and having at least one arm aperture each with dimensions sufficiently large to admit an arm yet not large enough to permit the padlock to be passed through the arm aperture; at least one of the two arms being provided at a first end with interlocking means capable of becoming locked by passage of the shackle of the padlock, each of the two arms being provided at a second end with engaging means capable of engaging with a locking rod forming part of an adjacent lockable container door; so that that when the arms are locked together when each is in engagement with an adjacent locking rod of a closed corresponding door, the fixed length of the locked security accessory prevents opening of the container doors by an unauthorized opening process and the shroud further restricts unauthorized access to the padlock by a shearing tool (bolt cutters or the like), as used by burglars to destroy the shackle or other parts of the padlock.).

Preferably the resistant material is a hardened steel; optionally a spring steel, or optionally another material resistant to interference by a thief.

In a first related aspect the interlocking means provided on at least one of the two arms at a first end comprises at least one aperture capable of accepting passage of the shackle of the padlock.

More particularly the interlocking means comprises a series of apertures at the first end of at least one arm, through any one of which apertures the shackle of a padlock may be passed.

Preferably each of the series of apertures through which the shackle of a padlock may be passed is elongated into the form of a slot.

Preferably the shroud includes two arm apertures in line, so that the second arm may be passed into one side of the shroud and out the other side.

Preferably the shroud has a top, sides, and an open base, the top being closed and one pair of opposite sides including at least one set of arm apertures placed opposite to each other.

In a first subsidiary aspect neither arm is fixed to the shroud and the first arm is capable of becoming locked to the second arm by padlocking, inside the shroud, the interlocking mean of one arm to the interlocking means of the other arm.

In a second subsidiary aspect the first arm is fixed to a part of the shroud thereby forming an assembly capable of becoming locked to the second arm when the shackle of the padlock, while within the shroud, is passed through an aperture of the inter- locking means of the second arm previously passed through an arm aperture into the shroud.

In either subsidiary aspect, the padlock access aperture of the shroud is preferably restricted leaving just sufficient space for operation of the padlock so that there is no space for the application of a shearing tool or other destructive device to the shackle of the padlock.

In a related aspect the interior space within the shroud is restricted leaving just suffi- cient space for operation of the padlock so that there is no space for the application of a shearing tool or other destructive device to the shackle of the padlock.

Preferably the interior space within the shroud is small enough to restrict the use of burglar's tools within it and large enough to permit application or removal of a locking means.

In either subsidiary aspect, the engaging means on each arm preferably comprises a recurved or hooked end capable of wrapping around and thereby engaging with a locking rod of a corresponding container door.

Preferably, securement of the invention about the locking bars of the container door involves a procedure in which the at least one arm is provided with means to engage with a corresponding locking bar so that in use the engagement means are drawn together thereby preventing the locking bars from moving apart as would happen during opening of the container doors.

More particularly a version of the invention comprises (1) a pair of arms made of a resistant material, (2) each arm having at one end a hook capable of being hooked around a locking bar of the container, (3) the length of the locking bars being sufficient to allow the two arms to reach between the two farthest locking bars across the opening of the container, (4) one arm having at the end remote from the hook a shroud, (5) the other arm having at the end remote from the hook a series of apertures each capable of accepting a locking means.

PREFERRED EMBODIMENT The description of the invention to be provided herein is given purely by way of illus- trative example and is not to be taken in any way as limiting the scope or extent of the invention.

DRAWINGS Fig 1 : is an elevational view of the openable end of a typical container of the type used for shipping containerized freight showing the doors, and in addition having an embodiment of the invention applied between a distant pair of the locking bars.

Fig 2: is a closer view of the invention, in place (an elevational view).

Fig 3: is a plan view of the invention as shown in Fig 2.

Fig 4: is a cutaway view of the shroud and padlock area of the invention, as shown in Fig 2.

Fig 5: shows preferred apertures fashioned in an arm.

The solution to the problem expressed previously in this document particularly comprises restricting any access by a thief to the components of a padlock used to lock a container door (or the like) by means of a shroud substantially protecting the padlock; the padlock being used to secure together sets of locking bars using locked-together arms that reach across the openable end of a container. While this invention cannot

control burglaries involving the picking of locks it does make the breaking open of a container (such as with bolt cutters used for cutting through shackles of padlocks) much more difficult.

EXAMPLE 1 It should be made clear that this invention provides an accessory 103,104,200 for a lockable container door 100. No modification of at least most kinds of shipping or storage container or lorry doors is required. This accessory comprises an externally applied door securing means that is capable of being secured (with an ordinary padlock 302) about locking bars of the container doors so that the container doors cannot be opened until the accessory is removed. (Preferably the padlock is selected to be relatively difficult to pick because picking the lock is the only remaining weakness of this type of security accessory). The accessory has usually two arms made of a rigid, resistant material such as 50 x 10 mm or 32 x 7 mm rectangular steel bar, hardened and galvanised after shaping. There is a locking means so that relative movement (pulling apart, end from end) of the arms on a secured container can be prevented and generally this involves passing the shackle of a padlock 302, while it is within the shroud, through apposed holes 201 in one or both arms so that the arms, each of which terminates in a hook passing around the locking bars of the door, cannot be pulled apart to allow the doors to open. Of course, the padlock shackle could be passed through the holes in or or both arms outside the hole, but it is accessible to bolt cutters or the like if not inside the shroud.

Bolt cutters make very short work of conventional padlocks, so this padlock is concealed within a shroud also made of a hardened steel-preferably from a short length (typically 220 mm long, 100 mm square box-section steel at least 3 mm thick. We prefer to provide the shroud with a welded lid (of 5 mm steel) so that access to the shackle is reduced. (In some countries the tendency of venomous creatures to inhabit such cavities may lead to the provision of holes through which insecticide can be squirted).

This shroud effectively prevents the jaws of a bolt cutter, each of which tends to have

considerable depth, from reaching the body or shackle of the padlock. Yet the shroud is not so small that it prevents placement or removal of the padlock through one or more holes, nor its being locked in place with a key.

EXAMPLE 2 In this preferred embodiment (as drawn), one arm is rigidly attached by welding to the exterior of the shroud) and the shackle of the padlock simply passes through one of a set of holes in the other arm. The padlock is pulled against the interior wall of the shroud if tension is applied to the arms, pulling them apart by an illegal opening activity. That is how the two arms are effectively locked together in this Example.

Preferably the arm which is welded to the exterior of the shroud has a dogleg bend included so that a pulling apart of the arms acts in a straight line.

In the second Example, where one arm is permanently welded to the shroud (and preferably a hard welding material is used); the shroud is provided with a slot-shaped aperture (303,304) at each of two opposite sides so that the moveable arm may pass right through, and may be locked in place within the shroud (as in Fig 3) by means of a shackle of a padlock passing through a selected hole. Hence the accessory is locked onto the locking bars and secures the container door. The padlock is protected.

In either Example, securement of the invention about the locking bars of the container door involves a procedure in which the at least one arm is provided with means to engage with a corresponding locking bar and the engagement means are drawn together before being locked in place thereby preventing the locking bars from moving apart as would happen during opening of the container doors. There is likely to be some slack because of differences in spacing of locking bars on containers, as compared to the inter-hole pitch along the arm or arms, so the hooks 105,106 should be long enough to retain the arms in place even if the arms are not drawn tightly together.

A series of apertures through which the shackle of a padlock (an example locking means) may pass is provided in at least one arm. In original designs these are 8 mm diameter holes 201 placed along the centre of the bar. (In the first Example, the holes in one arm may be spaced apart at a different pitch as compared to the other arm, so that an optimum spacing can be achieved). I have found that vertically oriented slits with about an 8 mm width are more convenient to use, and to have a larger hole at one end, like a keyhole shape (see Fig 5; showing a row of keyhole holes 501 in an arm 195 104 having a recurved hook 106), is even more convenient because in some cases it can be a fiddle to insert a padlock while working in a confined space inside the shroud. (It is always possible to use the ordinary locking points on the locking handles, as usual, for temporary closure, and to rely on this security accessory when the container is to be left overnight or is shipped away. Keyhole shaped holes can be cut more easily before 200 the steel is hardened.

Furthermore, a series of small holes 502 are conveniently provided along the moving arm 104 for the external-to-shroud insertion of a seal such as Customs inspection seal that can prove that the doors have not been opened.

Of course a determined thief can still destroy the door totally by removing the locking 205 bars, but in general the force required to do this will exceed a reasonable level and mak make excessive noise. It might even pull the entire container along the ground. (Some people trying to break into containers fitted with this security accessory clearly have pulled the container around using a vehicle but still have not gained entry).

Alternatively, both arms may pass through a larger slot aperture within the shroud 210 (which is now free to slide along the arms until it hits the padlock) and be capable of sliding relative to each other until a pair of holes match, and then of being locked together within the shroud by means of a padlock shackle passing through the apposed holes in order to secure the container door.

Referring in particular to Figures 1 to 4, a version of the invention comprises (1) a pair 215 of arms 103 and 104 made of a resistant material, (2) each arm having at one end a hook 105 and 106 capable of being hooked around a locking bar 102... of the container 100, (3) the length of the locking bars being sufficient to allow the two arms to span the distance between the two farthest locking bars across the opening of the container, (4) one arm 103 being at one end 305 welded 301 to a shroud 200, (5) the other arm 104 220 having at the end remote from the hook a series of apertures 201 (or 501,502) each capable of accepting a shackle of a padlock-the locking means. Note that the lengths of the hooks 105 and 106 is preferably sufficient to allow some play, in case the hole (s)

used for the padlock were not precisely correct for the spacing of the particular container doors in use. The shroud 200 includes a pair of slots 303 and 304 capable of admitting the arm 104 so that it can slide through the shroud.

Fig 4 shows a shroud 400, and in cutaway view (401) the position of a padlock 302 with its shackle passing through a hole 201 in arm 104 inside the shroud. 403 indicates the direction in which access to the padlock is obtained. It will be appreciated that actions other than use of a standard key with the padlock are substantially restricted.

Fig 5 shows some alternative types of perforations through an isolated moving arm 104.

Perforations 501 are keyhole-shaped perforations to use with a shackle of a padlock, and perforations 502 are for use with seals.

VARIATIONS One variation would have the shroud fixed to a very short arm so that it overlies one hook. In this case, adjustment may be more difficult. The arm 103 is provided with a bend that allows the other arm to project from the shroud through aperture 303.

Another variation (already mentioned) has the shroud serving only as a padlock protector. The padlock shackle passes through holes in both arms; both of which pass through a wider slot in the shroud and are held parallel. In this instance the shroud is possibly liable to be lost be careless employees, but it may be even easier and cheaper to make this variation of the invention. Judicious hole spacing may allow a fairly tight grip of the locking bars of the container by the arms of the invention.

Possibly the shroud may be dispensed with (for the latter variation) if one has enough confidence in the resistance of the padlock itself or if the invention is used to replace (in case of damage or the like) the usual locking means provided for on a container door.

COMMERCIAL BENEFITS or ADVANTAGES

In its first period of exposure, this invention has successfully prevented container theft even though the thieves used a vehicle to cause considerable damage to the exterior of the container. In another type of use, the security accessory provided peace of mind for the owners of a shipment of professional movie cameras and lenses being shipped by sea between sets in two 48-foot containers.

This security accessory for a storage or shipping container, or lorry doors has the advantage that it requires no modification to the container. Furthermore there is no "monitoring system". A consignor or consignee simply has to hand a security accessory according to this description to its trucking firm so that any container can be fully secured at the wharf-or even before shipping begins. Legitimate access as may be required by Customs officials is permitted through the supply of a key.

The presence of the protective device and its operation is clear to a thief who, though he may suspect that the container holds valuables, will appreciate that entry will be a good deal more difficult than formerly.

The invention is cheap enough that"dummy containers"can also be protected as well as the ones holding valuables.

Existing padlocks can be used, and no complex technology is required, so that builders (for example) can rely on the invention for storing their goods at remote sites.

Although several preferred examples as described above have been disclosed for illus- trative purposes, those skilled in the art will appreciate that various modifications, additions, and substitutions are possible without departing from the scope and spirit of the invention as set forth.

Finally, it will be understood that the scope of this invention as described and/or illus- trated within this provisional specification is not limited to the preferred embodiments described herein for illustrative purposes, Those skilled in the art will appreciate that various modifications, additions, and substitutions are possible without departing from the scope and spirit of the invention as set forth in the following claims.