GB2326620A - A tamper proof seal with window - Google Patents

Description

DESCRIPTION SEAL DEVICE The present invention relates to a seal device suitable for use in locking the doors of freight vehicles and containers, the seal device not being indestructible, but serving to guarantee to the receiving official that the container has not been opened during transport.

Due to the increasing number of thefts from containers and vehicles, it has become common practice to use seals. Organised gangs of thieves possess sophisticated equipment, the use of which helps to reduce the signs of a break-in sufficiently for it to go undetected. This is important in preventing detection of seals having been broken, especially when the crime is repeated, because the geographic site where the theft occurred cannot be defined.

The seal device should have sufficient mechanical strength and resilience to deter thieves from attempting to break the seal using small easily concealed equipment so that the thief is obliged to use more cumbersome means such as bolt cutters. However, the seal should be designed such that any damage to it should be obviously apparent to the observer.

Many types of seal are already known. Most of these seals comprise a sleeve formed in a housing, a stem which engages in the sleeve and a locking mechanism to lock the stem in the sleeve.

In one type of seal, the distal end of the stem is attached to the sleeve housing such that mating of the stem and the sleeve forms a loop or staple. The stem is usually a twisted metal cord or an inverted U-shaped rod.

Where a rod is used, one end is usually both journalled and spring mounted in the housing such that when the seal is in its unlocked configuration, the free end of the rod is biased clear of the sleeve and is rotatable about the mounting. The seal is locked by urging the rod's free end, against the spring bias, into the sleeve until it engages a locking mechanism contained therein.

Containers are often provided with a staple and pivoted hasp. The hasp is placed over the staple and the free end of the stem is fed through the staple aperture.

The stem is then locked in the sleeve to seal the container doors). Alternatively the container may be provided with a pair of alignable apertured handles or lugs through which the stem is fed before it is locked in the sleeve, sealing the container.

Seals of either type can employ similar known locking means provided on the stem and/or the sleeve.

The locking mechanism provided on the seal may be of various types. In one design, the stem is provided with a locking groove adjacent its free end. The sleeve is provided with a resilient elastic or sprung locking member. When the stem is pushed into the sleeve, the locking member is urged towards the sleeve wall until the stem groove reaches the locking member at which point the locking member locates in, or 'snaps into' the groove, locking the stem in the sleeve.

In some types of seal, the locking member is latched and can be pulled free of the groove by means of a key operated lever mechanism, so releasing the stem. Other locking means employed include providing a threaded aperture, linking the outside of the housing and the sleeve, in which is located a threaded grub. The grub is attached to a crank, external of the housing, by a weakened joint. After the stem has been located in the sleeve, the grub is, by means of the crank, tightened against the cord. The crank is then sheared from the grub to prevent untightening of the grub.

Other locking means include providing the sleeve with one or more circumferentially disposed sprung ball bearings which rotate only in the direction of insertion of the stem. Insertion forces the ball bearings apart so that they bear upon the stem and prevent its withdrawal.

However, whichever type of seal is employed and whatever the resilience of the materials used, it is possible using professional cutting equipment to cut through the stem of the lock, drill out a portion of the stem locked into the sleeve and then to glue the cut free end of the stem into the sleeve. Such tampering with seals of the prior art is not readily detectable.

The object of the invention is therefore to provide a seal device which is designed so that any internal damage is difficult to conceal.

In accordance with the present invention there is provided a seal device wherein an elongate member extends from a housing to form a loop and at least one end of the elongate member can be drawn through an aperture in the housing in order to shorten the loop, a locking mechanism within the housing serving to hold the loop in its shortened state, and wherein at least part of the elongate member passing through the housing is arranged to be visible externally of the housing.

Preferably the elongate member is visible through solid material comprising at least part of the housing walls.

Preferably, one end of the elongate member is rigidly fixed to the housing.

In one embodiment, the housing includes a windowed chamber through which the elongate member passes and which enables that part of the elongate member to be visible.

In another embodiment, the housing includes a block of transparent material through which the elongate member passes and which enables that part of the elongate member to be visible.

Advantageously, the block of transparent material provides a magnifying function to increase the visibility of the elongate member passing therethrough.

The transparent material may be disposed so as to also render at least part of the locking mechanism visible externally of the housing.

At least one of the apertures from which the elongate member extends from the housing may be countersunk such that re-gluing of the cord adjacent an aperture, but external of the housing, is clearly visible.

It is therefore be extremely difficult to employ the above mentioned cutting, drilling and gluing technique without such tampering being obviously apparent to an observer.

By way of example only, and with reference to the accompanying drawing, which is a perspective view from the front and above, an embodiment of the present invention will now be described.

The drawing illustrates a seal 10 according to the present invention in a sealed configuration. The seal 10 comprises a housing 20, a metal cord 30 fixedly anchored at its distal end in the housing 20, a T-shaped window 40 provided in the side of the housing 20, and a T-shaped chamber sealed by the window 40. The T-shaped chamber comprises a transversely disposed primary chamber 50 in which two sections of cord 30 are visible through the window 40, and an axially disposed side cavity 60 in which the bottom half of a numbered tag 70 fits snugly so as to support the tag 70 against the window 40. The window in front of the main cavity is shaped (bowed) so as to magnify the main chamber.

The distal end 80 of the metal cord 30 is attached to a cylindrical lug 90 which is embedded in the housing 20 adjacent one corner. The cord 30 passes through the chamber 50 and out through an aperture 100 in the top surface 110 of the housing 20. To seal a container, the proximal end 115 of the cord 30 is passed through aligned lugs or a staple (not shown) as discussed previously and the seal closed. In the closed configuration (as shown), the cord 30 passes back into the housing 20 through a second aperture 110 in the top surface 120 of the housing 20, such that the portion of the cord 30 extending between the apertures 100 and 110 forms a loop. The cord 30 passes back through the chamber 50 and passed a pivoted locking cam 130 mounted beyond but adjacent the chamber 50. The cam 130 is spring biased and positioned in frictional contact with the cord 30 so as to allow movement of the cord 30 such as to reduce the size of the loop, but to restrain movement in the opposite direction by pressing into it. The proximal end of the cord passes out through an aperture 140 in the base 150 of the housing. The loop may be tightened by pulling on the proximal end of the cord 30 extending from the aperture 140.

With cord locks, it is a security requirement that the cord is pulled tight on sealing. If the cord is cut, the metal wires forming the windings of the cord will tend to unwind and splay outwards. These features conventionally make it difficult, but not impossible, to cut the cord and to conceal the damage caused. It is possible to rewind the chord and to solder the end to prevent unwinding. Furthermore, if the cut is made just above one of the apertures in the housing it is often possible, despite the pre-tightening of the cord to reinsert the cord into the housing below the aperture and glue it in position. In the locks of the prior art, such tampering would not be evident. However, with a lock of the present invention, for example as illustrated, such tampering would be evident.

The present invention is just as applicable to seals in which a rigid U-shaped rod replaces the cord. With seals of this kind, it is usual for the thief to cut the rod at positions adjacent each aperture in the top surface of the housing, and then to drill out a piece of rod from each aperture and glue the severed rod back into position. Such tampering will be readily apparent if the seal housing is provided with a window arrangement as illustrated in the above embodiment.

The present invention is not restricted to a lock employing a cam type locking mechanism. Any prior art method of locking a cord or rod may be employed.

The components of the seal, especially the housing and the stem are preferably made of strong resilient materials, such as steel and reinforced plastic. However strength is not of primary importance, rather, the ability to detect tampering using the seal.

The invention is not restricted to the details of the foregoing embodiment. All features of the specific embodiment are interchangeable with any other features mentioned in this specification.

Claims (9)

1. A seal device wherein an elongate member extends from a housing to form a loop and at least one end of the elongate member can be drawn through an aperture in the housing in order to shorten the loop, a locking mechanism within the housing serving to hold the loop in its shortened state, and wherein at least part of the elongate member passing through the housing is arranged to be visible externally of the housing.

2. A seal device as claimed in claim 1 in which the elongate member is visible through solid material comprising at least part of the housing walls.

3. A seal device as claimed in claim 1 or claim 2 in which one end of the elongate member is rigidly fixed to the housing.

4. A seal device as claimed in any one of claims 1 to 3 in which the housing includes a windowed chamber through which the elongate member passes and which enables that part of the elongate member to be visible.

5. A seal device as claimed in any one of claims 1 to 4, in which the housing includes a block of transparent material through which the elongate member passes and which enables that part of the elongate member to be visible.

6. A seal device as claimed in claim 5 in which the block of transparent material provides a magnifying function to increase the visibility of the elongate member passing therethrough.

7. A seal device as claimed in any one of claims 1 to 6 in which the transparent material may be disposed so as to also render at least part of the locking mechanism visible externally of the housing.

8. A seal device as claimed in any one of claims 1 to 7, in which at least one of the apertures from which the elongate member extends from the housing may be countersunk such that re-gluing of the cord adjacent an aperture, but external of the housing, is clearly visible.

9. A seal device substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.