GB2308574A - Security sealing of containers - Google Patents

Description

Security Seal Field of the invention The present invention relates to a bolt seal for sealing a container and providing a visible indication of any attempt to open the container or gain access to its contents.

Background of the invention When sending a container, it is common to place a security seal on it to ensure that no one should tamper with its contents during its various stages in transit. The security seal is, for example, fitted to a hasp that prevents the container from being opened and as responsibility for the container is passed from one handler to the next, the integrity of the seal is checked to ensure that the container has not been opened by an unauthorised person.

There are known purely indicative seals that may be broken without the use of special tools, an example of a purely indicative seal being a strip seal made of a plastics material or sheet metal. There are also known seals that offer a physical deterrent to prevent the container from being opened, the invention being concerned with one such form of security seal, herein referred to as a bolt seal.

A bolt seal comprises a bolt and a bush. The bolt and the bush may be made of metal, a plastics material or a metal encased in a plastics material. Once the bolt is pushed home in the bush, the two are locked together permanently by a locking mechanism built into the bush. To open the container, the bolt has to be severed using a bolt cutter or an angle grinder and for this reason it acts not only as an indicative seal but also as a physical deterrent preventing the casual thief from gaining access to the interior of the container.

It is common practice when using bolt seals to seal containers, to fit a second indicative seal to the same container. The secondary seal may not necessarily be applied at the same time as the original bolt seal. It may, for example, be applied by customs authorities at an exit port to indicate that the original seal was checked at entry and also to provide a secondary deterrent. It is also possible that the second seal may be fitted due to lack of confidence in the security of the bolt seal. In this context, it should be noted that unlike metal strip seals, bolt seal generally make no provision for checking correct engagement of their locking mechanism other than the physical position of the bolt within the bushing.

When a secondary seal is applied to indicate that a previously applied seal has been checked, there is no indication as to which of the seals was the first to be applied and there is no direct interaction or relationship between the two seals. Indeed, the two seals can come from different manufacturers using varying coding sequences.

Summary of the invention According to one aspect of the present invention, there is provided a method of sealing a container which comprises fitting a bolt seal and an indicative seal to the container, wherein the indicative seal is secured to, or formed integrally with, the bolt seal such that the bolt seal may not be removed from the container while the indicative seal remains intact.

According to a second aspect of the invention, there is provided a bolt seal for use as a primary seal to inhibit access to the interior of a container and provide a visual indication in the event of the container being opened, the bolt seal having means for attaching thereto, or being formed integrally with, an indicative seal, the bolt and the bush of the bolt seal being inseparable from one another while the indicative seal remains intact.

In the present invention, the two seals are not independent of one another but interact. The indicative seal does not only act as an independent second check that the container has not been opened but increases the security of the bolt seal by interfering with its removal from the container.

Conveniently, the head of the bolt and the bush may be formed with an integral lug having a slot for receiving a strip seal made of sheet metal or plastics material.

In use, after the bolt seal has been inserted into the hasp and its two parts pushed firmly together, a metal, plastics, or lead and wire indicative seal can be applied through the two lugs. Fitting such a secondary seal effectively seals the two halves of the bolt seal in its original position.

Brief description of the drawings The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 shows the two parts of a bolt seal of the invention before they are mated, Fig. 2 is an end view of the bolt as seen in the direction of the arrows II-II in Fig. 1, Fig. 3 is an end view of the bush as seen in the direction of the arrows III-III in Fig. 1, Fig. 4 is a plan view of a metal indicative strip seal, Figure 5 shows the bolt seal of Fig. 1 after the bolt has been inserted in the bush the strip seal of Fig. 4 fitted to the slots in the lugs projecting from the head of the bolt and the bush, and Figures 6 to 9 show views similar to Figure 5 of four further embodiments of the invention.

Detailed description of the preferred embodiment Figure 1 shows a bolt seal comprising a bolt 10, having a tapered end 12, an annular recess 14 near its tapered end 12 and a head 30. In this described embodiment, the head 30 and part of the length of the shaft of the bolt are encased in a sleeve 32 of plastics material that is cast with the bolt in situ by a transfer moulding technique. A metal bush 16 is formed with a blind bore for receiving the tapered end of the bolt within which bore there is formed an annular recess 18 for receiving a spring clip (not shown). As with the bolt, the bush 16 of the illustrated preferred embodiment of the invention is encased in a plastics sleeve 20. The same identification number 0000843 is applied to the bush and the bolt for example by laser printing, hot foiling, or stamping.

In use, the bolt 10 is passed through a hasp to prevent a container door from being opened and it is then pushed into the bush 16. Bolt cutters or an angle grinder must be used to destroy the bolt before the door can be opened and as the same bolt cannot then be replaced it will provide a visual indication of the tampering with the container. The plastics sleeves will be deformed if pliers or any other tool is used in an attempt to pull the bolt out of its bush.

If the bolt or part of the bolt is replaced after it has been damaged while breaking into the container, it will not be possible for the new bolt to have the same identification code imprinted on it.

As so far described, the bolt seal is conventional. In this embodiment of the invention, the bolt and the bush have apertures for receiving an indicative seal, these apertures being constituted by slots 26 and 28 formed in lugs 22 and 24 projecting respectively from the head of the bolt and the bush. These lugs may be formed in only the plastics sleeves 32 and 20 but this could allow them to be cut away without leaving obvious marks on the seal. It is therefore preferred, in the case where the bolts are encased in plastics sleeves, that these lugs should be formed at least in part from the metal of the bolt and the bush both to make them difficult to remove and to leave bare metal as a sign of tampering with the seal.If the lugs are formed in the plastics sleeves only, then the design of the sleeve and the detail thereon should be configured so as to indicate the removal of any section of the sleeve.

Figure 4 shows a metal strip seal that can be used as an indicative seal in conjunction with the bolt seal of Fig. 1.

The seal 34 has a metal strip 36 stamped with a unique code 0000843 marking to allow the seal to be traced. A specially formed head 40 is secured to one end of the strip 36 by a rivet 48 and the other end of the strip is stamped to form a tongue 38. When the end of the strip 36 is inserted into the head 40, the tongue 38 is bent out of the plane of the strip and catches within the head 40 to prevent the end from being retracted from the head. In this sealed position, the end of the tongue 38 can be seen through holes 42 and this provides clear confirmation that the strip seal has been correctly fitted.

In Fig. 5, the seal 34 of Fig. 4 is shown fitted to the bolt seal of Fig. 1 and apart from achieving an improved level of security by adding an extra indicative seal, this also eliminates some of the known ways for tampering with bolt seals.

Typical methods applied to compromise a bolt seal include 1) spinning the bolt within the bush to cause the inner sealing ring to fail through erosion by friction.

2) cutting the bolt at the point of entry into the bush, drilling out the remaining portion of the bolt and refitting using a split pin inserted along the axis of the bolt.

3) using of a small hydraulic jack (common in the motor industry) to pull the bolt from the bush, and reassembling to provide the visual appearance of a complete seal.

In all three of the above cases, the secondary seal will be damaged by opening the primary seal. The bolt cannot be spun in the bush without totally destroying the secondary seal and if the secondary seal is only just long enough to pass around the two lugs, then the bolt and the bush cannot be pulled apart without damaging the secondary indicative seal. Thus, the integrity of the secondary seal not only indicates that it has not been removed but also that the primary seal to which it is fitted has not been removed.

Because, as mentioned above, many bolt seals provide no confirmation that their internal mechanisms have been fully engaged, they can if improperly fitted be removed without leaving any indication of tampering. However, by using a secondary seal to hold the bolt and the bush together, the value of the bolt seal as a physical deterrent is enhanced.

The application of the secondary indicative seal directly to the body of the primary seal provides one compact seal assembly rather than individual seals fitted to the container locking mechanisms. Apart from improving security, this makes the container easier to open by the legitimate recipient of the container.

The secondary indicative seal is shown as having numeric codes corresponding to those of the primary seal and though this is not essential, it does add to the security.

The position of the slots in the bolt shown in Figs. 1 to 3 can be varied and they need not necessarily be formed on projecting lugs. For example, transverse aligned slots could be formed in sections of the bush and the bolt that overlap when the bolt seal is in use to allow a strip seal to be inserted at right angle to the axis of the bolt. As a further alternative, the bolt and the bush could have axial bores for receiving a wire and lead seal. The illustrated embodiment is however preferred because very little of the strip seal 34 is hidden within the bolt seal and it is not possible to hide a join in the strip seal by positioning it carefully within the aperture in the bolt seal.

A seal formed of a metal encased in plastics material is preferred because it combines internal strength with an easily marked outer surface to warn of any attempt to force the seal apart. It is however alternatively possible to use a less expensive seal made only of metal or one made entirely of plastics material.

Figures 6 to 8 show embodiments of the invention that are designed for use with a dedicated strip seal and have male and female connecting members for non-releasably engaging connecting members on the ends of the strip seal. Whereas in Figure 5 the strip of the bolt seal is doubled over and is twice length of the bolt seal, in these embodiments there is only one length of strip that extends between the head of the bolt and the bush of the bolt seal.

The connecting members are in themselves conventional and designed in the same way as the male and female connecting members on the opposite ends of known plastics strip seals.

In each case, once a male connecting member is inserted into its female, a resilient barb within the female engages in the recess defined by the male connecting member to prevent the connecting members from being separated without the strip 72 being damaged. The distinctive feature in these embodiments lies in the fact that the connecting members are moulded integrally into the ends of the bolt seal.

In the case of the embodiment of Figure 6, male mushroomlike connecting members 60 and 62 are formed on the bolt head 64 and the bush 66, respectively of the bolt seal and female connecting members 68 and 70 are formed on the ends of the strip 71 of the strip seal.

In Figure 7, the head 74 of the bolt has a male connecting member 72 engaging with a female connecting member 76 on one end of the strip 78, whereas the other end of the strip 78 has a male connecting member 80 that engages in a female connecting member 72 moulded into the bush 84 of the bolt seal.

In Figure 8, both ends of the strip 90 have spade-like male connecting members 92 that engage in female connecting members 94 formed on the ends of the bolt seal. In this case, the male members 92 are designed for insertion radially rather than axially into the female members 94 moulded as part of the bolt head and the bush of the bolt seal.

The embodiment of Figure 9 is generally similar to that of Figure 8 and differs from it in that the strip 96 of the strip seal is formed as an extension of the head of the bolt of the bolt seal. Both parts of the strip seal are therefore moulded as an integral part of the bolt seal.

Claims (8)

1. A method of sealing a container which comprises fitting a bolt seal and an indicative seal to the container, wherein the indicative seal is secured to, or formed integrally with, the bolt seal such that the bolt seal may not be removed from the container while the indicative seal remains intact.

2. A bolt seal for use as a primary seal to inhibit access to the interior of a container and provide a visual indication in the event of the container being opened, the bolt seal having means for attaching thereto, or being formed integrally with, an indicative seal, the bolt and the bush of the bolt seal being inseparable from one another while the indicative seal remains intact.

3. A bolt seal as claimed in claim 2, wherein the attachment means are constituted by apertures in the bolt and the bush of the bolt seal for receiving the indicative seal.

4. A bolt seal as claimed in claim 3, wherein the head of the bolt and the bush are formed with integral lugs each having a slot for receiving a strip seal serving as the indicative.

5. A bolt seal as claimed in claim 3 or 4, wherein the bolt and the bush are formed of metal encased in a plastics material.

6. A bolt seal as claimed in claims 4 and 5, wherein the lugs are formed at least in part integrally with the metal parts of the bolt and the bush.

7. A bolt seal as claimed in claim 2, wherein the indicative seal comprises a single strip that extends between the head of the bolt and the bush of the bolt seal, the attachment means comprising connection pieces on the head of the bolt and on the bush for non-releasably engaging with mating connection pieces on the respective ends of the strip of the indicative seal.

8. A security seal constructed arranged and adapted to operate substantially as herein described with reference to and as illustrated in Figures 1 to 3 and 5 or any one of Figures 6 to 8 of the accompanying drawings.

8. A bolt seal as claimed in claim 7, wherein the connection piece on the head of the bolt or on the bush of the bolt seal comprises a male coupling member having a recess and the end of the strip seal has a female coupling member including a resiliently biased catch engageable in the recess of the male coupling member.

9. A bolt seal as claimed in claim 7, wherein the connection piece on the end of the strip seal comprises a male coupling member having a recess and the head of the bolt or on the bush of the bolt seal is formed with a female coupling member including a resiliently biased catch engageable in the recess of the male coupling member.