GB2469474A

GB2469474A - A tamper-evident lock

Info

Publication number: GB2469474A
Application number: GB0906431A
Authority: GB
Inventors: David Alexander Mcgrouther
Original assignee: VIP System Ltd
Current assignee: VIP System Ltd
Priority date: 2009-04-15
Filing date: 2009-04-15
Publication date: 2010-10-20
Anticipated expiration: 2029-04-15
Also published as: GB2469474B; GB0906431D0

Abstract

A tamper-evident lock (10) for coupling two objects (46, 48) together where the objects (46, 48) are provided with apertures extending therethrough that can be arranged co-axially, comprises a body (12) having a first portion (14) and a second portion (16) that are mutually engageable at mating faces thereof by non-return engagement means (14e,16r) provided on the first and second portions (14,16). The lock (10) also comprises an attachment member (18) attaching the first and second portions (14,16) together. In use, the first and second portions (14,16) are insertable through the co-axial apertures in the two objects (46, 48) from opposite sides and are mutually engageable with each other. The attachment member (18) extends from the first portion (14), around the exterior of the objects, to the second portion (16).

Description

"Tamper-Evident Lock" The present invention relates to a tamper-evident lock for coupling first and second objects together so that they cannot be separated without making separation evident. One use of this technology is in coupling front and rear plate members of a licence plate assembly together. The present invention also relates to a lockable assembly and a method of coupling first and second objects together.

Licence plates for hire vehicles (e.g. private hire vehicles and taxis) display data relating to the respective vehicle. Such data typically includes the name of the issuing authority, the plate number, the maximum number of passengers, the category of licensed vehicle, a description of the licensed vehicle, the vehicle registration mark and the expiry date of the licence. Hire vehicles are typically licensed for a period of one year, after which the licence plate is removed and replaced by a new licence plate for the following year.

Conventional licence plates are typically made from a single piece of 3mm thick rnoulded polycarbonate, which has the licence data printed thereon.

After the plates have expired, to ensure complete destruction, the plates are fed into a heavy-duty industrial shredder to reduce them to granules of less than 10mm square. The financial and environmental cost of destruction of hundreds of thousands of such plates every year is significant.

An alternative design of licence plate has the form of an assembly including a front plate member and a rear plate member that together form a housing for a printed (e.g. paper) licence. This is much better for the environment, as the only disposable part after a year's use is the paper licence, rather than the entire licence plate assembly. The front and rear plate members can thereafter be reused. However, a problem arises as to how the paper licence can be adequately secured between the front and rear plate members, so that a genuine licence cannot be removed and According to a first aspect of the present invention there is provided a tamper-evident lock for coupling two objects together, the objects being provided with apertures extending therethrough that can be arranged co-axially; the lock comprising: a body comprising a first portion and a second portion that are mutually engageable at mating faces thereof by non-return engagement means provided on the first and second portions; and an attachment member attaching the first and second portions together, the attachment member being a different component from the engagement means; wherein, in use, the first and second portions are insertable through the co-axial apertures in the two objects from opposite sides and are mutually engageable with each other, with the attachment member extending from the first portion, around the exterior of the objects, to the second portion.

When the tamper-evident lock is engaged, the two objects cannot be separated without cutting/severing the attachment member. The first portion and the second portion are held together by the non-return engagement means, which does not allow subsequent separation.

If the attachment member is cut/severed/broken, the tamper-evident lock can then be removed from the objects, so that the two objects can be separated from each other. However, the damage to the attachment member is obvious upon inspection, indicating tampering.

Typically, the mating faces are locatable within the apertures of the objects.

This makes the mating faces inaccessible to someone wishing to tamper with the locked objects.

Typically, the body of the lock has an axial passage extending therethrough for receiving a fixing device.

The axial passage enables the lock (and the two locked objects) to be attached to a third object. For example, if the two locked objects are front and rear plate members of a licence plate assembly, the third object to which they are attached could be a licensed vehicle.

Typically, the non-return engagement means comprises an enlarged diameter portion on one of the first and second portions and a corresponding recess in the other of the first and second portions.

Optionally, the body of the lock is provided with a cap that is locatable over the axial passage to close the end of the passage.

The cap can increase the aesthetic appeal and it also prevents dirt from getting into the axial passage of the lock and around any fixing device received therein.

Typically, the first portion has a flange provided at an end thereof, the flange being larger than the apertures in the objects.

The flange limits the extent to which the first portion can be pushed into the apertures in the objects, thus facilitating the engagement of the non-return means.

Typically, the second portion has a smaller cross-sectional area than the apertures in the objects.

This enables the locked first and second portions to be withdrawn from the co-axial apertures after the attachment member has been cut. The first and second portions can be withdrawn by pulling on the flanged end of the body of the lock.

Typically, the first and second portions are substantially cylindrical.

Optionally, the body has a longitudinal axis and the attachment member is attached to the first and second portions at the two axial ends of the body.

Hence, the attachment member is readily locatable around the exterior of the two objects. "Attached" is used to mean either formed integrally with, or formed separately and then attached.

Typically, the tamper-evident lock comprises a plastics material.

According to a second aspect of the present invention there is provided a lockable assembly comprising: a first object and a second object, each of which have a respective aperture extending therethrough that can be arranged co-axially; and a tamper-evident lock according to the first aspect of the present invention.

Typically, the lockable assembly includes more than one set of co-axial apertures and more than one respective tamper-evident lock.

Preferably, the first and second objects each have coaxial apertures provided at a plurality of locations around the periphery thereof and wherein a respective tamper-evident lock is provided for each pair of co-axial apertures.

Typically, the first and second objects are provided with male and female engagement means provided in a continuous path. The continuous path may optionally be adjacent (fairly close to) to the periphery of the objects.

Preferably, the first and second objects are sufficiently rigid and have short enough dimensions between neighbouring tamper-evident locks, to prevent the opening, by leverage, of a gap greater than the length of the male engagement means into the female engagement means.

Preferably, the mating faces of the tamper-evident lock are located within the apertures of the objects, such that the mating faces are inaccessible once the non-return engagement means is engaged.

Typically, the attachment member is a tight fit around the exterior of the objects, e.g. the attachment member is dimensioned so that it wraps around the first and second objects in a close fit. This helps to hold the mating faces within the apertures.

Optionally, the first and second objects comprise front and rear plate members, for example, of a licence plate assembly.

According to a third aspect of the present invention there is provided a method of coupling first and second objects together, wherein the first and second objects are provided with apertures extending therethrough that can be arranged co-axially; the method including the steps of: taking a tamper-evident lock comprising: a first portion and a second portion that are mutually engageable at mating faces thereof by non-return engagement means provided on the first and second portions, the first and second portions forming a body of the lock; and an attachment member attaching the first and second portions together; arranging the first and second objects so that their apertures are co-axial; inserting the first portion of the lock into the apertures from one side thereof; locating the attachment member around the exterior of the objects and inserting the second portion of the lock into the apertures from the other side thereof; and pressing the first and second portions together to engage the non-return engagement means, thereby locking the first and second objects together.

Optionally, the body of the lock has an axial passage therethrough, and the method includes the subsequent step of inserting a fixing device into the passage and attaching the first and second coupled objects to a third object by the fixing device.

Optionally, the second portion of the tamper-evident lock has a smaller cross-sectional area than the apertures in the first and second objects, and the method includes the step of decoupling the first and second objects from each other by severing the attachment member and withdrawing the engaged first and second portions together out of the apertures.

An embodiment of the invention will now be described, by way of example only, and with reference to the following drawings, in which:-Fig 1 shows a schematic, perspective view of a tamper-evident lock of the present invention; Fig 2 shows a side view with interior detail of the tamper-evident lock of Fig 1 being used to secure a licence plate assembly to a vehicle; Fig 3 shows a cross-sectional view with additional detail of the tamper-evident lock of Fig 1; Fig 4 shows the tamper-evident lock of Fig 1 being used with a different embodiment of a licence plate assembly (only part of the licence plate assembly shown); Fig 5 shows a plan view of the Fig 4 embodiment, showing the whole licence plate assembly; and Fig 6 shows a schematic sectional side view of the licence plate assembly of Fig 4.

Referring to Fig 1, a tamper-evident lock 10 includes a substantially cylindrical body 12 which in turn comprises a first portion 14 and a second portion 16. Fig 1 shows the lock 10 in a disengaged position. The lock 10 can be brought into an engaged position by pushing the first and second portions 14, 16 together.

The first portion 14 includes a main body 14m and a flange 14f of increased diameter extending from the upper end of the main body 1 4m.

The second portion 16 has an axial bore 17 running therethrough, which accommodates the first portion 14 when the lock 10 is in the engaged position.

The first portion 14 also has an axial bore running therethrough, which defines an axial passage 1 2b of the body 12. The axial passage 1 2b extends through the flange 1 4f and the main body 1 4m.

The first portion 14 and the second portion 16 are mutually engageable at mating faces thereof by non-return engagement means (described below with reference to Figs 3 and 4) provided on the first and second portions 14, 16. The non-return engagement means typically comprises non-return clips. The non-return engagement means are typically provided on the radially outer surface of the first portion 14 and on the radially inner surface of the bore 17 of the second portion 16. When pushed together, the non-return engagement means engage to hold the first and second portions 14, 16 permanently in the engaged position.

The lock 10 also includes an attachment member in the form of a strap 18.

The strap 18 is connected to the first and second portions 14, 16 at the axial ends of the body 12. Hence, one end of the strap 18 is connected to the flange 1 4f at the upper axial end of the body 12, and the other end is connected to the base of the second portion 16. The strap 18 attaches the first and second portions 14, 16 together, whether or not the non-return engagement means is engaged. The strap 18 prevents the separation of the first and second portions 14, 16 beyond the length of the strap 18.

The length of the strap 18 is exaggerated in Fig 2.

The body 12 of the lock 10 is provided with a cap 20 that is locatable over the axial passage 1 2b to close the end of the passage 1 2b. The cap 20 is attached at a hinge 20h to the circumference of the flange 14f.

The lock 10 (first portion 14, second portion 16, strap 18 and the cap 20) is integrally formed and comprises a plastics material.

Referring now to Fig 2, the tamper-evident lock of Fig 1 is being used to secure a licence plate assembly 22 to part of the body 24 of a vehicle.

The licence plate assembly 22 includes a front plate member 26, a rear plate member 28 and a paper licence (not shown) located between the front and rear plate members 26, 28. It should be noted that only one corner of the licence plate assembly 22 is shown in Fig 2. The licence plate assembly 22 also has three other similar corners, which are lockable in the same way.

In Fig 2, the lock 10 is inserted through co-axial apertures in the front and rear plate members 26, 28. The lock 10 is in the engaged position, with the first portion 14 seated within the bore 17 of the second portion 16. The non-return engagement means is engaged.

The axial passage 1 2b in the body 12 is adapted to receive a fixing device (see Fig 2). In this embodiment, the fixing device is a bolt 30, but it could alternatively be a screw. At four locations on the vehicle body 24 (corresponding to the four corners of the licence plate assembly), the vehicle body 24 has a respective axial passage 24b, through which a respective bolt 30 passes. The bolt 30 is adapted to engage a nut 32 on the underneath side of the vehicle body 24, to clamp the licence plate assembly 22 to the vehicle body 24.

Fig 3 shows the tamper-evident lock 10 in more detail, in particular, the non-return engagement means.

The main body 14m of the first portion 14 terminates in an enlarged diameter portion 14e at its lower end. The second portion 16 has a base 16b from which the strap 18 extends, and a cylindrical wall 16w. The cylindrical wall 16w has a recessed portion 16r provided at its lower end, just above the base 16b. The recessed portion 16r is dimensioned and located to co-operate with the enlarged diameter portion 1 4e of the first portion 14. The rest of the cylindrical wall 16w is dimensioned and located to co-operate with the rest of the main body 14m of the first portion.

The non-return engagement means comprises the enlarged diameter portion 1 4e of the first portion and the recessed portion 1 6r of the second portion 16.

When the non-return engagement means is engaged, the enlarged diameter portion 14e is located in the recess 16r in a snug fit. The first portion 14 cannot be pulled out of the second portion 16 because the outer diameter of the enlarged diameter portion 1 4e is larger than the inner diameter of the cylindrical wall 16w above the recess 1 6r.

Figs 4 and 5 show the tamper-evident lock 10 engaged with a slightly modified embodiment of a licence plate assembly 42. The bolt 30 and its connection to a vehicle body (not shown) are the same as shown in Fig 2.

The licence plate assembly 42 is rectangular, has four corners 42c and includes a front plate member 46 and a rear plate member 48. Coaxial apertures are provided through the front and rear plate members 46, 48 in the region of each of the four corners 42c. The cylindrical body 12 of a respective tamper-evident lock 10 is located in the coaxial apertures at each corner 42c, the non-return means of the first and second portions 14, 16 being engaged and the strap 18 spanning around the edge of the licence plate assembly 42. A channel/groove is provided in the rear surface of the rear plate member 48, so that the strap 18 can be received within this channel. This ensures that the strap 18 lies co-planar with the rear surface of the licence plate assembly 42 and does not project therefrom. As shown, the strap 18 is sized to closely fit the outer contours of the licence plate assembly 42. This prevents the cylindrical body 12 from being able to be manipulated out of the co-axial apertures, thereby preventing access to the non-return means.

The front plate member 46 has a male engagement means that comprises a protrusion 50 on its rear surface. The rear plate member 48 has a female engagement means that comprises a recess 52 in its front surface.

A seal in the form of a compression sealing ring 60 is located in the recess 52. The sealing ring 60 is compressed between the protrusion 50 and the recess 52.

As shown in Fig 5, the protrusion 50 and recess 52 form a closed path which surrounds an inner chamber of the licence plate assembly 42. The inner chamber houses a licence 54, which is optionally formed from paper.

The sealing ring 60 helps to keep the inner region water-tight.

The protrusion 50 and recess 52 are located (and suitably dimensioned) so that the protrusion 50 is aligned with and engageable in the recess 52 when the co-axial apertures of the front and rear plate members 46, 48 are aligned. Fig 4 shows the protrusion 50 received within the recess 52. The protrusion 50 and the recess 52 both have a relatively narrower neck portion so that they form a "snap-fit" arrangement, locking the front and rear plate members 46, 48 together.

The rear plate member 48 has a thickened portion 48t to the exterior of the recess 52, at least at the four corner regions, and optionally also along the whole peripheral region outwards of the recess 52. This helps to make the licence plate assembly 46 thick enough so that the whole of the cylindrical body 12 is received in the co-axial apertures. This in turn ensures that the non-return means (enlarged diameter portion 14e and recessed portion 16r) is inaccessible.

Fig 6 shows a schematic side view of the front and rear plate members 46, 48, with the protrusion 50 engaged in the recess 52.

A method of coupling first and second objects to a third object together will now be described. In this example, the first and second objects are the front plate member 26 and the rear plate member 28 and the third object is the vehicle body 24; however, equally, this method applies to coupling many different types of objects.

In use, the licence plate assembly 22 is assembled by inserting a paper licence between the front and rear plate members 26, 28 and by bringing the plate members 26, 28 together with their respective apertures aligned (co-axial) at each of the four corners. Optionally, the plate members 26, 28 may be designed so that they push-fit together in the correct alignment.

The tamper-evident lock 10 is then applied to the pair of apertures at one of the four corners of the plate members 26, 28, by: inserting the first portion 14 of the lock 10 into the apertures from the side of the front plate member 26; guiding the path of the strap 18 around the exterior of the plate members 26, 28; inserting the second portion 16 of the lock 10 into the apertures from the side of the rear plate member 28; and pressing the first and second portions 14, 16 together to engage the non-return engagement means.

The flange 1 4f is larger than the apertures in the front and rear plate members 26, 28, which prevents the first portion 14 from being pressed all of the way into the apertures and aids the engagement of the non-return engagement means.

The second portion 16 has a smaller cross-sectional area than the apertures in the front and rear plate members 26, 28.

Three additional tamper-evident locks 10 are now applied to the apertures at the other three respective corners of the licence plate assembly 22, in the same way.

Thus, the plate members 26, 28 are now locked together at all four corners.

To secure the locked licence plate assembly 22 to the vehicle, at one corner, the axial passage 12b is aligned with the passage 24b in the vehicle body 24, and the bolt 30 is inserted through the passages 12b, 24b and secured by the nut 32 on the underneath of the vehicle body 24.

Finally, the cap 20 is closed over the bolt 30. This is repeated at the other three corners.

The licence plate assembly 42 would be assembled and secured to a vehicle (or stationary structure) in the same way, with the additional step of pressing the front and rear plate members 46, 48 together to engage the protrusion 50 in the recess 52.

If a person wished to gain access to the inner chamber of the licence plate assembly 42, e.g. to replace a genuine licence with a forged licence, he would find that the front plate member 46 could not be removed from the rear plate member 48 because this is prevented by the four tamper-evident locks 10.

The non-return engagement means is engaged so the first portion 14 cannot be pulled out of engagement with the second portion 16.

Furthermore, the non-return engagement means cannot be accessed (e.g. for tampering/breaking) because it, together with the whole cylindrical body 12, is within the co-axial apertures. The cylindrical body 12 cannot be rotated out of the co-axial apertures because the cylindrical body 12 is rigid and because the strap 18 is a close fit around the exterior of the licence plate assembly 42. Furthermore, the close-fitting strap 18 prevents direct upwards removal of the cylindrical body 12 from the co-axial apertures.

So, the person needs to first remove the tamper-evident locks 10. This cannot be done without cutting the strap 18, which reveals the tampering.

Alternatively, the forger might attempt to force the front and rear plate members 46, 48 apart by applying leverage at a midpoint along one of the edges of the licence plate assembly. However, the front and rear plate members 46, 48 are formed of rigid polycarbonate plastic. The front and rear plate members 46, 48 are sufficiently rigid and have short enough length and width dimensions between the tamper-evident locks at two neighbouring corners 42c, such that, even if the forger were to try to lever the two plates apart in the middle, the gap created would be less than the distance that the protrusion 50 extends into the recess 52. Hence, the paper licence 54 is still inaccessible.

Hence, a licence plate forger cannot now remove the licence from the licence plate assembly without cutting at least one of the four straps 18; a cut strap 18 provides evidence of tampering. The non-return engagement means prevents disengagement of the first portion 14 from the second portion 16. Moreover, the non-return means is inaccessible, since it is located within the apertures of the licence plate assembly, making tampering even more difficult.

When the licence plate assembly is to be recycled (an outdated paper licence replaced with a new paper licence), the front and rear plate members 26, 28 can be decoupled from each other by severing the straps 18 and withdrawing the engaged first and second portions 14, 16 from the front of the licence plate assembly (the side of the flange 14f). The second portion 16 being of a smaller cross-sectional area than the apertures allows the second portion 16 to follow the first portion 14 out of the apertures. Hence, although locked against forgers, the lock 10 is easily removable at the recycling stage. After replacing the paper licence, four new tamper-evident locks 10 are applied to the licence plate assembly, as described above.

Modifications and improvements may be incorporated without departing from the scope of the invention. For example, it is not necessary to use the tamper evident lock in connection with a licence plate assembly. The tamper evident lock could alternatively be used for coupling any two objects together. The invention is not necessarily limited to vehicles, and could be used with stationary structures.

The present invention is not limited to locking first and second objects that have pre-existing apertures. If the first and second objects do not already have apertures, the method could be adapted to include a preliminary step of forming apertures that can be arranged coaxially in the objects to be locked.

The attachment member is not necessarily connected to the first and second portions at the axial ends of the body. The attachment member could alternatively pass through the axial passage of the body and physically connect on the inside of the passage, spaced from the ends.

Alternatively, the attachment member could extend down the outside of the body 12 and physically connect on the exterior of the body, spaced from the ends.

In an alternative embodiment, neither of the first and second portions has a flanged end, such that the lock can be pulled through the apertures in both directions.

In Fig 2, both ends of the body 12 of the lock 10 protrude from the apertures in the objects. However, in an alternative embodiment, the body 12 may not extend completely through the apertures. For example, the second portion 16 may be relatively shorter with respect to the apertures, such that the axial (lower) end of the second portion 16 is located within the apertures in the objects. The end of the strap 18 that is attached to the second portion 16 could therefore also be located within the apertures.

The cap 20 is not an essential element of the invention.

The first and second portions 14, 16, could be reversed in position with respect to the front and rear plate members 26, 28, such that the first portion 14 is inserted from the side of the rear plate member 28, etc. The bolts 30 (or other fixing members) do not necessarily attach directly to the vehicle. Alternatively, a base unit could be provided, and the bolts 30 could fasten to the base unit instead of to the vehicle. The base unit could be attached to the vehicle by any suitable means, e.g. by magnets. A suitably strong type of magnet is a neodymium magnet. This is useful, for example, for attaching a licence plate to a vehicle that does not have pre-drilled apertures in the vehicle body for receiving the bolts 30.

The non-return engagement means could equally be described as an enlarged diameter portion on the second portion 16 and a recess in the first portion 14. The non-return engagement means can take any suitable shape.

In some embodiments, the second portion 16 is locatable within the first portion 14, instead of exterior thereto.

Claims

Claims 1. A tamper-evident lock for coupling two objects together, the objects being provided with apertures extending therethrough that can be arranged co-axially; the lock comprising: a body comprising a first portion and a second portion that are mutually engageable at mating faces thereof by non-return engagement means provided on the first and second portions; and an attachment member attaching the first and second portions together, the attachment member being a different component from the engagement means; wherein, in use, the first and second portions are insertable through the co-axial apertures in the two objects from opposite sides and are mutually engageable with each other, with the attachment member extending from the first portion, around the exterior of the objects, to the second portion.
2. A tamper-evident lock as claimed in claim 1, wherein the mating faces are locatable within the apertures of the objects.
3. A tamper-evident lock as claimed in claim 1 or claim 2, wherein the body of the lock has an axial passage extending thereth rough for receiving a fixing device.
4. A tamper-evident lock as claimed in any preceding claim, wherein the non-return engagement means comprises an enlarged diameter portion on one of the first and second portions and a corresponding recess in the other of the first and second portions.
5. A tamper-evident lock as claimed in any preceding claim, wherein the first portion has a flange provided at an end thereof, the flange being larger than the apertures in the objects.
6. A tamper-evident lock as claimed in any preceding claim, wherein the second portion has a smaller cross-sectional area than the apertures in the objects.
7. A tamper-evident lock as claimed in any preceding claim, wherein the body has a longitudinal axis and wherein the attachment member is attached to the first and second portions at the two axial ends of the body.
8. A lockable assembly comprising: a first object and a second object, each of which have a respective aperture extending therethrough that can be arranged co-axially; and a tamper-evident lock as claimed in any preceding claim.
9. A lockable assembly as claimed in claim 8, including more than one set of co-axial apertures and more than one respective tamper-evident lock.
10. A lockable assembly as claimed in claim 9, wherein the first and second objects each have coaxial apertures provided at a plurality of locations around the periphery thereof and wherein a respective tamper-evident lock is provided for each pair of co-axial apertures.
11. A lockable assembly as claimed in any of claims 8 to 10, wherein the first and second objects are provided with male and female engagement means provided in a continuous path.
12. A lockable assembly as claimed in claim 11 when dependent on claim 10, wherein the first and second objects are sufficiently rigid and have short enough dimensions between neighbouring tamper-evident locks, to prevent the opening, by leverage, of a gap greater than the length of the male engagement means into the female engagement means.
13. A lockable assembly as claimed in any of claims 8 to 12, wherein the mating faces of the tamper-evident lock are located within the apertures of the objects, such that the mating faces are inaccessible once the non-return engagement means is engaged.
14. A lockable assembly as claimed in any of claims 8 to 13, wherein the attachment member is a tight fit around the exterior of the objects.
15. A lockable assembly as claimed in any of claims 8 to 14, wherein the first and second objects comprise front and rear plate members.
16. A method of coupling first and second objects together, wherein the first and second objects are provided with apertures extending therethrough that can be arranged co-axially; the method including the steps of: taking a tamper-evident lock comprising: a first portion and a second portion that are mutually engageable at mating faces thereof by non-return engagement means provided on the first and second portions, the first and second portions forming a body of the lock; and an attachment member attaching the first and second portions together; arranging the first and second objects so that their apertures are co-axial; inserting the first portion of the lock into the apertures from one side thereof; locating the attachment member around the exterior of the objects and inserting the second portion of the lock into the apertures from the other side thereof; and pressing the first and second portions together to engage the non-return engagement means, thereby locking the first and second objects together.
17. A method as claimed in claim 16, wherein the body of the lock has an axial passage therethrough, and wherein the method includes the subsequent step of inserting a fixing device into the passage and attaching the first and second coupled objects to a third object by the fixing device.
18. A method as claimed in claim 16 or claim 17, wherein the second portion of the tamper-evident lock has a smaller cross-sectional area than the apertures in the first and second objects, and wherein the method includes the step of decoupling the first and second objects from each other by severing the attachment member and withdrawing the engaged first and second portions together out of the apertures.
19. A tamper-evident lock as hereinbefore described with reference to the drawings.
20. A lockable assembly as hereinbefore described with reference to the drawings.
21. A method of coupling first and second objects together as hereinbefore described with reference to the drawings.