GB2336622A

GB2336622A - Cable security seal

Info

Publication number: GB2336622A
Application number: GB9808658A
Authority: GB
Inventors: Clive Albert Brown
Original assignee: BLOXWICH TRANSPORT PROD Ltd
Current assignee: BLOXWICH TRANSPORT PROD Ltd
Priority date: 1998-04-24
Filing date: 1998-04-24
Publication date: 1999-10-27
Also published as: GB9808658D0

Abstract

In a cable security seal a body (1) is provided with a threaded bore (3) which intersects a through passage (2), and a threaded locking member (5) is adapted to be screwed into the bore to clamp superimposed end portions of a cable (14) against an opposed wall of the passage.

Description

11 2336622 1 CABLE SECURITY SEAL This invention relates to a new or

improved cable security seal of the kind in which a body has a passage therethrough, and a flexible inextensible member is attached at opposite ends to the body, one of the ends being passed through the passage for attachment to the body.

In known security seals of the kind set forth one end of the cable is permanently attached to the body at one location, and the other end is passed through the passage for attachment to the body, for example by the provision of a wedge member in the body, or by deforming the material of the body onto the cable.

According to our invention, in cable security seal of the kind set forth the body is provided with a threaded bore which intersects the passage, and a threaded locking member is adapted to be screwed into the bore to clamp superimposed end portions of the cable against an opposed wall of the passage.

The opposed wall may be provided with a recess into which the end portions are deformed in order to enhance the clamping effect. In such a construction the inner end of the locking member may comprise a clamp face of a configuration complementary to that of the recess.

The bore may be normal to the axis of the passage.

Preferably the threaded locking member is incorporated into a key and comprises a clamp portion carried from a handle through a n.eck or weakened connecting portion of reduced diameter. The neck is arranged 30 to transmit sufficient torque from the handle to the clamp portion in order 2 to achieve an effective clamping of the superimposed portions of the cable, any additional or greater torque causing the handle to separate from the clamp portion by a fracture occurring at the neck.

This ensures that the seal cannot be released, other than by severing the cable.

Conveniently the relative lengths of the clamp portion and the bore are so chosen that the fracture occurs at an intermediate position within the length of the bore. This increases security since the outer end of the clamp portion is not readily accessible. The clamp portion cannot normally be removed from the bore without "drilling ouC. To increase security further, this can be prevented by har dening the clamp portion by heat treatment to resist drilling or by adding a "drill resistanC inset into the exposed bore portion.

One embodiment of our inventioq is illustrated in the accompanying drawings in which:- Figure 1 is an exploded view of a cable security seal, including a sectionthrough a body; Figure 2 is a perspective view of the seal; Figure 3 is a longitudinal section through the body; Figure 4 is a transverse section through the body; Figure 5 is a view similar to Figure 4 but 'howingthe seal in its final operative stage; and p:. -:.. - 1 3 Figure 6 is a plan of the body illustrated in Figure 5 but showing a modification.

The cable security seal illustrated in the drawings comprises a body 1 of generally oblong rectangular outline, suitably in the form of a hollow aluminium extrusion. The body is provided with an open-ended longitudinally extending through passage 2 and a transverse boe 3 positioned at substantially the mid point in the length of the body traverses the passage 2. The passage 2 is of elongate cross section with the longer dimension directed towards the main axis of the bore 3. The bore 3 is screw threaded internally and has a base 4 which is of conical outline and which is disposed in a position spaced from the opposite side of the passage 2.

The body 1 is adapted to receive a locking member incorporated into a key 5. The key 5 comprises a, clamp portion 6 connected to a shank 7 through a neck or connecting portion 8 of reduced diameter. The shank 7 is integral with a handle 9 comprising a first portion 10 integral with the shank 7, and an inclined manually rotatable arm 11. The clamp portion 6 terminates in a clamp face 12 of conical outline complementary to that of the recess 4. A screw threaded portion 13 is adapted to be received in the threaded bore 3, and the shank 7 is of plain cylindrical outline having a diameter slightly less than the internal root diameter of the threads of the threaded bore 3.

In use an inextensible member, suitably a helically stranded cable 14, is passed through openings in objects to be sealed together and free ends are then brought together in superimposed relationship to form a loop 15. The ends are then fed through the passage 2 until they emerged 4 from the opposite end of the body 1 as illustrated in Figure 2. Either before, or at that stage, the threaded portion 13 of the key 5 is screwed into the bore 13 by rotation of the arm 11 about the bore 3 as an axis and, as the clamp member 3 is screwed home, the superimposed portions 16, 17 of the inextensible member 14 are imprisoned or clamped together between the clamp face 12 and the conical recess 4. Further rotation of the handle 9 in the same direction causes the superimposed portions to be permanently crimped between the two faces and displaced transversely as illustrated in Figure 3 of the drawings, thereby ensuring a substantially permanent connection between the body 1 and ' the inextensible member 14. Upon increasing the torque to the key 5 in the same direction, the shank 7 fractures at the neck 8 leaving the threaded portion permanently located in the body 1 as illustrated in Figure 5. The handle 9 is then discarded.

During rotation of the key 5 before fracture, the shank 7 is at least partially supported by the root diameter of the threaded bore 3 to reduce i the chance of any side force causing the shank 7 to fracture prematurely.

The threaded portion 13 is shorter in length than the length of the bore 3. This ensures that after fracture of the neck 8 the outer end of the threaded portion 13 lies well below the outer end of the bore.

Since the outer end of the threaded portion 13 lies below the outer end of the bore 3 in the final stage illustrated in Figure 5, that end is generally inaccessible and the threaded portion 13 can be removed only by "drilling ouC.

To prevent "drilling ouC the threaded portion 13 may be hardened by heat treatment.

For increased security the free, open, end of the bore 4 could be plugged, preferably a drill resistant insert.

In a modification, opposite sides of the body 10 may be crimped towards each other by the use of a suitable tool such that displaced portions 19, 20 obstruct the outer end of the bore 3 and cover a substantial area of the exposed neck 8.

As illustrated in Figures 4 and 5 of the accompanying drawings, after the threaded portion 13 has been screwed home, the inner portion 17 of the inextensible member 14 is spread substantially to cover the area of the recess bore 4, by a clamping effect from the other, outer, portion 16 which, in turn, is spread by the face 12 but to a lesser extent.

is The smaller, transverse, dimension of the passage 2 is chosen to suit the diameter of a particular inextensible flexible member with which the body is to be used, in such a way, that when the two end portions 16, 17 of the member are inserted through the passageway they are constrained to be superimposed upon each other as illustrated, and are not provided with sufficient space for them to lie side, by, side in the passage. This ensures that the material of the end portions 16, 17 is crimped between the two faces 12 and 14 as described above, and the cable 14 and the body 1 cannot be separated from each other.

6

Claims

1. A cable security seal of the kind in which a body has a passage therethrough, and a flexible inextensible member is attached at opposite ends to the body, one of the ends being passed through the passage for attachment to the body, in which the body is provided with a threaded bore which intersects the passage, and a threaded locking member is adapted to be screwed into the bore to clamp superimposed end portions of the cable against an opposed wall of the passage.

2. A seal according to Claim 1, in which the opposed wall is provided with a recess into which the end portions are deformed in order to enhance the clamping effect.

3. A seal according to Claim 2, in which the inner end of the locking member comprises a clamp face of a configuration complementary to that of the recess.

4. A seal according to any preceding claim, in which the bore is 20 normal to the axis of the passage.

5. A seal according to any preceding claim, in which the threaded locking member is incorporated into a key and comprises a clamp portion carried from a handle through a neck or weakened connecting portion of reduced diameter.

6. A seal according to Claim 5, in which the neck is arranged to transmit sufficient torque from the handle to the clamp portion in order to achieve an effective clamping of the superimposed portions of the cable, 7 any additional or greater torque causing the handle to separate from the clamp portion by a fracture occurring at the neck.

7. A seal according to Claim 5 or Claim 6, in which the connecting portion is carried from a shank, and the shank is of plain cylindrical outline of a diameter slightly less than the internal root diameter of the threaded bore.

8. A seal according to Claim 6 or Claim 7, in which the relative 10 lengths of the clamp portion and the bore are so chosen that the fracture occurs at an intermediate position within the length of the bore.

9. A seal according to Claim 8, in which the clamp portion is hardened to prevent "drilling out".

is

10. A seal according to Claim 8, in which the free, open, end of, the bore is plugged by a plug.

11. A seal according to Claim 10, in which the plug comprises a drill 20 resistant insert.

12. A seal according to Claim 8, in which opposite sides of the body are crimped towards each other to obstruct the outer end of the bore and cover a substantial area of the exposed neck.

13. A cable security seal substantially as described herein with reference to and as illustrated in the accompany drawings.