GB2424032A

GB2424032A - Padlock with security fastener engaging shackle

Info

Publication number: GB2424032A
Application number: GB0504953A
Authority: GB
Inventors: Stuart Norcott
Original assignee: Assa Abloy Ltd
Current assignee: Assa Abloy Ltd
Priority date: 2005-03-10
Filing date: 2005-03-10
Publication date: 2006-09-13
Also published as: IE20060174A1; GB0504953D0

Abstract

A one-shot padlock comprises a body 1 and a shackle 2 whose opposite ends are able to be located within the body 1. An end of the shackle 1 is able to be retained in the body by a security fastener 3 which is able to be secured in the body 1 of the padlock and to engage the shackle. The security fastener 3 may comprise a shackle retaining pin 13 with an internally screw-threaded post 16. A security bolt 15 may have an externally screw-threaded shaft 15A to be screwed into the pin 13. The drive head 19 may be sheared off the bolt 15 upon tightening leaving the fastener 3 permanently screwed to the padlock in a tamper-resistant manner.

Description

PADLOCK

This invention relates to a padlock and more particularly to what is referred to herein as a one-shot padlock. A one-shot padlock is also sometimes referred to as a disposable padlock and is used when a padlock is required for one use only. Such padlocks may, for example, be used to provide a secure fastener for goods in transit, the padlock being removed on arrival. In a typical case, such a one-shot padlock does not have a lock mechanism and the padlock is detached by cutting through the shackle of the padlock with bolt cutters.

There have been many proposals for designs of one-shot padlocks. GB2027788 shows one example.

The level of security provided by such a padlock and the cost of the padlock vary considerably. For example, there are some one-shot padlocks that consist of bodies of plastics materials and bent wire shackles; such padlocks are relatively cheap but also relatively insecure. Other oneshot padlocks have metal bodies and shackles of predetermined shape, usually formed from a U shaped metal bar, with some kind of spring ratchet or other clamp mechanism within the body; padlocks of this latter kind tend to be more secure but also expensive to manufacture.

It is an object of the invention to provide a one-shot padlock which is both relatively secure and relatively inexpensive.

According to the invention, there is provided a one- shot padlock comprising a body and a shackle whose opposite ends are able to be located within the body, an end of the shackle being able to be retained in the body by a security fastener which is able to be secured in the body of the padlock and to engage the shackle.

Security fasteners are manufactured in large volumes and economically. By using an appropriate security fastener it is possible to provide a oneshot padlock which is both relatively secure and relatively inexpensive to manufacture. The term "security fastener" as used herein refers to a fastener which once secured is very difficult or impossible to release and is therefore resistant to tampering, or to a fastener which, if tampered with, can be seen to have been tampered with.

The security fastener is preferably a screw-threaded fastener. It may pass through the body of the padlock and have a part (which may or may not be screw-threaded) which engages the end of the shackle to retain it in the body of the padlock, or it may be screwed into the end of the shackle. Embodiments of the invention described below illustrate arrangements of both these kinds.

In the case where the security fastener passes through the body of the padlock, it preferably extends from one side of the body to the other and, partway through its passage through the body, engages the end of the shackle.

The fastener may comprise separate parts inserted from opposite sides of the padlock and screwed together.

In the case where the security fastener is screwed into the shackle, it is preferably screwed into the end of the shackle from the exterior of the body of the padlock, preferably from the bottom of the body of the padlock (the shackle entering the body of the padlock through its top) Whilst any of a wide variety of security fasteners may be employed, it is preferred that the security fastener is non-detachably secured in the body of the padlock.

Preferably the security fastener is of a kind which is fastened to the body of the padlock and, at the end of the fastening process, a part of the security fastener is broken off, for example, sheared off, the fastener, leaving it very difficult or impossible to remove the fastener from the padlock body. Fasteners of this kind are known per Se.

Other tamper-resistant or tamper-evident fasteners may be employed.

Preferably the body of the padlock is made of metal, preferably steel. Generally a metal body is more robust than a body of plastics material.

Preferably the shackle is of a predetermined shape, rather than being flexible. More preferably, the shackle is made of metal. A metal shackle of predetermined shape can be made very secure.

The shackle is preferably a U' shape, preferably with both limbs of the U approximately the same length. The body of the padlock preferably has two bores, which may be blind bores, for receiving respective ends of the shackle.

The bores are preferably parallel. Whilst it is within the scope of the invention to provide a security fastener for each end of the shackle, it will usually be sufficient to provide only one security fastener securing only one end of the shackle.

As will be understood from the description above,

there is usually no purpose in providing a padlock of the invention with a lock mechanism, such as a key-operated lock or a combination lock, and, to reduce cost, it is preferred that there is no lock.

By way of example, certain embodiments of the invention will now be described with reference to the accompanying drawings, of which: Fig. 1 is a perspective view of a first form of one- shot padlock in a fully fastened condition; Fig. 2 is an exploded perspective view of the padlock shown in Fig. 1; Fig. 3 is a sectional view of the padlock of Fig. 1; Fig. 4 is a side view of a security bolt employed in the padlock of Fig. 1; Fig. 5 is a perspective view of a second form of one- shot padlock in a fully fastened condition; Fig. 6 is an exploded perspective view of the padlock shown in Fig. 5; and Fig. 7 is a sectional view of the padlock of Fig. 5.

Referring first to Figs. 1 to 3, there is shown a one- shot padlock generally comprising a body 1, a U shaped shackle 2 and a security fastener 3. All the parts are made of metal.

The body 1 of the padlock is of generally cuboidal shape having a top face 4, a front face 5, end faces 6, a bottom face 7 and a rear face (not visible in Figs. 1 to 3). A pair of parallel blind bores 8A, 8B of circular cross-section extend downwardly into the body of the padlock from the top face, the bottoms of the bore 8A, 8B being connected to the bottom face of the body 1 by relatively narrow passageways 9A, 9B. The body of the padlock also has a further passage 10 of circular cross- section that extends through the body and intersects the blind bore 8A. The ends of the passage 10 are of enlarged diameter. The enlarged end on the front face 5 is referenced bA in Figs. 1 and 2, the enlarged end on the rear face not being visible.

The U shaped shackle 2 is rigid and has a pair of limbs hA, 11B of equal length and of a circular cross- section that match the cross-section of the bores 8A, 8B and are at the same spacing so that the limbs hA, 11B are a snug fit in the bores 8A, 8B. The limb hA of the shackle 2 is formed with a curved recess 12 on its inner side (the side facing the limb 11B).

The security fastener 3, once in the fully fastened condition shown in the drawings, generally comprises a shackle-retaining pin 13, a washer 14 and a security bolt 15. The shackle-retaining pin 13 has an internally screw-threaded tubular part 16 and an enlarged head 17.

The external diameter of the tubular part 16 matches the diameter of the passage 10 and the curvature of the exterior of that part matches the curvature of the curved recess 12 in the shackle 2. The security bolt 15 has an externally screw-threaded shaft iSA and can be screwed into the tubular part 16 of the retaining pin 13. In the fully fastened condition shown in the drawings, the bolt 15 has a rounded head 18 received in the enlarged end 10A of the passage 10. The screw-threading of the parts 15A and 16 is not shown in Figs. 1 to 3.

Fig. 4 shows the bolt 15 prior to being fully fastened and it will be seen that a hexagonal drive head 19 is integrally formed on the bolt 15 and connected to the head 18 by a tapered neck 20. In use, before the security fastener 3 is inserted, the shackle 2 is inserted into the body 1 of the padlock, with the limbs hA, 11B of the shackle received in the blind bores 8A, 8B. In that position the curved recess 12 in the limb 11A of the shackle 2 lines up with the passage 10 through the body 1 of the padlock and it is therefore possible for the tubular part 16 of the retaining pin 13 to be inserted into the body of the padlock from its rear face. The bolt 15, as shown in Fig. 4, and the washer 14, are then inserted into the body of the padlock from its front face 5 and the bolt 15 screwed into the tubular part 16 of the retaining pin using an appropriate tool to engage the hexagonal drive-head 19. As the fastener reaches full tightness in engagement with the opposite faces of the body 1 of the padlock, the torque required to screw the bolt 15 further into the tubular part 16 increases and finally the drive-head 19 is sheared off the rounded head 18 of the bolt 15 leaving the fastener 3 permanently screwed to the padlock in a tamper-resistant manner. The tubular part 16 of the retaining pin 13 engages in the recess 12 of the shackle and thereby prevents the shackle being removed from the body of the padlock. The bolt 15 may be of a design known per Se, for example, it may be a monodrive (RTM) 11 bolt.

When in due course it is desired to release the padlock, a bolt-cutter of appropriate strength is used to cut through the middle portion of the shackle. If the shackle is cut at the top of the limb hA, then the limb 11B and the curved portion of the shackle can be pivoted within the body of the padlock and removed.

Figs. 5 to 7 show a second form of one-shot padlock that is generally similar to the first form. In Figs. 5 to 7 parts corresponding to parts described with reference to Figs. 1 to 4 are referenced by the same reference numerals. The description below therefore focuses on the differences between the two forms of padlock.

The main difference between the two forms of padlock is that in the embodiment of Figs. 5 to 7, the bolt 15 is screwed into the extreme end of the limb hA of the shackle 2 being inserted from the bottom face 7 of the body 1 of the padlock. Thus, there is no need to provide the retaining pin 13, washer 14 or passage 10 in the body of the padlock. The narrow passageway 9A of the first form of padlock is therefore replaced by a wider passageway 19A to accommodate the bolt 15 and an additional narrow passageway 9C is provided extending transversely from the bottom of the blind bore 8A to the neighbouring end-face 6 of the body of the padlock. The limb hA has a screw- threaded blind bore 20 in its end to receive the externally screw- threaded bolt 15.

As will be understood, in use of the second form of padlock, the shackle is inserted into the bores 8A, 8B, and the bolt 15 then screwed into the end of the limb hA of the shackle until the drive-head 19 is sheared off. When it is desired to release the padlock, a bolt-cutter is again used to cut through the shackle 2.

Claims

- 10 - Claims 1. A one-shot padlock comprising a body and a shackle whose

opposite ends are able to be located within the body, an end of the shackle being able to be retained in the body by a security fastener which is able to be secured in the body of the padlock and to engage the shackle.
2. A padlock according to claim 1, in which the security fastener is a screw-threaded fastener.
3. A padlock according to claim 2, in which the security fastener passes through the body of the padlock and has a part which engages the end of the shackle to retain it in the body of the padlock.
4. A padlock according to claim 3, in which the security fastener extends from one side of the body to the other and, partway through its passage through the body, engages the end of the shackle.
5. A padlock according to claim 2, in which the security fastener is screwed into the end of the shackle.

- 11 -
6. A padlock according to claim 5, in which the security fastener is screwed into the end of the shackle from the exterior of the body of the padlock.
7. A padlock according to claim 6, in which the security fastener is screwed into the end of the shackle from the bottom of the body of the padlock.
8. A padlock according to any preceding claim, in which the security fastener is of a kind which is fastened to the body of the padlock and, at the end of the fastening process, a part of the security fastener is broken off, leaving it very difficult or impossible to remove the fastener from the padlock body.
9. A padlock according to claim 8, in which the part of the security fastener that is broken off is sheared off.
10. A padlock according to any preceding claim in which the body of the padlock is made of metal.
11. A padlock according to any preceding claim, in which the shackle is of a predetermined shape.

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12 - 12. A padlock according to any preceding claim in which the shackle is made of metal.
13. A padlock according to any preceding claim in which the shackle is a U' shape.
14. A padlock according to claim 13, in which both limbs of the U are of approximately the same length.
15. A padlock according to any preceding claim, in which the body of the padlock has two bores for receiving respective ends of the shackle.
16. A padlock according to claim 15, in which the bores are blind bores.
17. A padlock according to claim 15 or 16, in which the bores are parallel.
18. A padlock substantially as herein described with reference to Figs. 1 to 3, or Figs. 5 to 7, of the accompanying drawings.