GB2521199A

GB2521199A - A lock

Info

Publication number: GB2521199A
Application number: GB1322059.5A
Authority: GB
Inventors: Philip Jenkins
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-12-13
Filing date: 2013-12-13
Publication date: 2015-06-17
Also published as: GB201322059D0

Abstract

A lock having a housing with a socket and a cylinder plug inside the sock, the housing having a first row of outer locking holes 152 for receiving driver pins and a second row of locking holes 230, preferably also a third row, located radially around from the initial set of holes 130. This second set comprising relocker pins 240. The second and third row of outer pins prevent the plug 30 being rotated relative to the housing 20 to such an extent that the lock unlatches when it is bumped as the relocker pins engage with inner locking holes located in the plug. Preferably the radial width of the holes in the second and third rows of outer locking holes is narrower than the holes in the first row of locking holes. The relocker pins may have an upper part and a lower part, preferably each having an angled or slopping surface which engage with each other (Fig 4/5), the pins may also be shaped to prevent returning of the relocker pin (347 Fig 5).

Description

A lock The ptrt invention relates generally to a lock and finds particular. although not exclusive, utility in the prevention of locks being picked or bumped.

The invention primarily concerns pin tumbler locks (also known as rim locks and cylinde.r locks) but it can be. adapted for use with other lock types such as Euro-cylinder locks. The well known Yale i'1At) locks are typically pin tumbler locks.

Such locks typically include a socket within which a cylindrical plug, including a keyway, is rotatable; the plug comprising a row of holes extending from the keyway to its outer circumference. the housing also includes a row of holes extending to the outer surface of the plug and located in a corresponding manner with the phig's row of holes such that a pair of each of the housing's holes and each of the plug's holes are coaxial.

The point at which the outer circumference of the piug meets the socket in the housing is referred to as the shear line. Tn the locked position with the keyway slot located typically vertically, the coaxial holes contain a lower key pin arid an upper driver pin. A spring is provided above the driver pin urging the whole arrangement downwards. the length of each of the driver pins and key pins typically varies from iiolc to iiolc along thc row in accordaricc with thc kcy topography.

With a key inserted into the keyway the peaks and troughs along the key blade push the driver and key pins upwards in each hole. tf it is the correct key then the heights at which each driver pin and key pin meet will all be the same, relative to the plug, and will all be at the outer circumference of the plug such that the plug can be rotated within the housing.

Such locks are openable without the correct key by "htiiping" using a so-called "hump key". This is a key which fits inside the keyway hut has a blade topography of relatively low cut peaks and troughs.

Tn use, the key is not quite fully inserted into the keyway. A turning pressure is then applied to the key in the direction which the key would normally turn if it was the correct key (e.g. clockwise. The key is then "bumped" or knocked fully into the keyway. This has the effect that as the peaks move forward axially inside the plug, die key pins are knocked or jarred upwards inside the holes. Their kinetic energy is at least partially transferred to the driver pins above them moving them upwards too. the driver pins typically move upwards more cuickly tlnui the key pins such that for a moment the driver pins are all completely located inside the holes in the housing.

Accordingly, as long as the key pins have not moved upwardly to such an extent that they straddle the shear line (i.e. that the tops of each of the key pins have not the risen past the circumference of the plug), the turning pressure applied to the key will allow the plug to be rotated.

if the knocking of the key into the keyway does not successfully allow the plug to be rotated inside the housing, it can be repeated. One method uses a means of vibrating the key slightly hack and fonvards within the keywav to accelerate the pricess.

Once the plug has been rotated past the point where the rtvo rows of holes are coaxial the river pins have no effect.

A lock that has been opened this way can be relocked, by rotation of the plug back to its starting position, and the key removed without providing any indication of what has occurred.

Tt is desirable to provide a lick which cannot be opened by "bumping", and if someone does try to bump the lock, to trap the "bump key" used in the keyway.

in a first aspect, the invention provides a lock comprising a housing including a socket and a plug inside the socket, the plug comprising a keyway for accepting a key, the lock configured such that only with a correct key inserted into the kcyway is the plug rotatable within the housing, the housing further including a first row of at least one outer locking holes extending radially away from the perimeter of the socket, at least one of the first row of outer locking holes including a first driver pin located therein, the first driver pin being moveable axially within the at least one outer locking hole in the first row, and a first biasing means for axially urging the first driver pin towards the plug, the plug further comprising a row of at least one inner locking holes extending radially to the circumference of the plug being arranged coaxially with the first row of outer locking holes with the plug in a first rotational position relative to the housing, wherein at least one inner locking hole includes a key pin configured to be axially moveable therein with a key inserted into the keyway, the housing further comprising a second row of at least one outer locking holes extending radially away from the perimeter of the socket, at least one of the second row of outer locking holes including a relocker pin located therein, the relocker pin being moveable axially within the at least one outer locking hole in the second row, and a second biasing means for axially urging the relocker pin towards the plug. wherein the longitudinal axes of the first and second rows of outer holes:ire located distant from one another around, and in a common pme, the plate including the direction of rotation of the plug within the socket.

Accordingly, if a bump key is used so as to overcome the first row of outer locking holes and the driver and key pins therein, as the key and plug is rotated, so as to rotate the cam and thus withdraw the bolt of the overall locking device, the relocker pin(s) in the. second row of outer locking holes enters the row of inner locking holes and straddles the shear line such that further rotation of the plug is prevented, if the second row of outer locking holes is positioned radially between the first row of outer locking holes and the radial position at which the cam withdraws the bolt, and thus unlocks the overall locking device, then the overall locking device cannot be unlocked.

The invention also prevents against the lock being picked.

The plug may he substantially cylindrical. In this regard, the term cylindrical' includes other cross-sectional shapes such as octagonal and the hke. The socket may he substantially cylindrical.

The inner and outer locking holes may he substantially cylindrical, although other cross-sectional shapes are contemplated. The driver, key and relocker pins may tit closely within the holes. the inner and outer locking holes may have substantially the same cross-sectional shape as (inc ar)otllcr.

The first and second biasing means may he coil springs although other means are contemplated.

The housing may further comprise a third row of at least one outer locking holes extending radially to the circumference of the socket, at least one of the third row of outer locking holes including a relocker pin located therein, the relocker pin being moveahle axially within the at least one outer locking hole in the third row, and a third biasing means for axially urging the relocker pin towards the plug, wherein the axes of the first, second and third rows of outer holes are located distant from one another around, and in the same plane as, the circumference of the plug.

The third row of outer locking holes may be positioned radially on the other side from the first row of outer locking holes as the second row of outer locking holes.

In this way, if the key is turned in the opposite rotational direction to that in which the inner locking holes will correspond to the second row of outer locking holes, the inner locking holes \vlll correspond with the third row of outer locking holes.

\Vith the plug in a second or third rotational position relative to the housing the row of inner lockmg holes may be coaxial with the second or third row of outer locking holes such that the re]ocker pin is urged at least partially into the at least one inner locking hole when an incorrect key is present in the keyway, thus preventing the plug from further rotation relative to the housing.

Any of the first, second and third rows of outer locking holes may comprise more than one locking hole, and the ends of these outer locking holes adjacent the plug may be arranged substantially rectilinearly in rows parallel to the rotational axis of the plug.

The outer locking holes may extend to the exterior surface of the housing for ease of installation and replacement.

The row of inner locking holes may comprise more than one locking hole, and the ends of these inner locking holes adjacent the outer surface of the plug may he arranged substantially rectilinearly in a row parallel to the rotational axis of the plug.

At least one of the second or third rows of outer locking holes may he configured to Prevent the key pin from entering it as an incorrect key is pulled axially away, along the keyway. from the plug.

Ihc kcy p may bc moved upwards by thc peaks of the kcy as it is withdrawn from the keyway. This may push the relocker pin upwards at least partially back into the row of outer locking holes, however, by preventing the key pin from entering the outer hole the likelihood is that it will not be possible to completely withdraw the key from the keyway as at least one of the key pins will not be able to move completely above a particular peak on the key. In this way. the person trying to bump the lock will have to leave the key in the lock. This may he useful as it may provide evidence as to who had tried to hump the lock. For instance, fingerprints may he present on the key blade.

At least one of the second or third rows of outer locking holes may he configured to prevent the key pin from entering it as an incorrect key is pulled axially away, along the keyway, from the plug, by having a radial width smaller than the radial width of the axially located corresponding hole in the first row of outer locking holes.

In this way, if the key pins fit closely within the inner locking holes and the outer locking holes in the second or third rows have a smaller width then the key pins will not be able to enter them.

Although the term radial width' has been used it will he understood that the holes may not he cylindrical and other cross-sectional shapes arc possible such that the key pins will not enter the second or third row of outer locking holes.

The relocker pin may comprise non-return means for preventing the relocker pin from moving axially away from plug. Tn this way, the re]ocker pin may move towards the. plug but not away from it. this may aid retention of the key in the keyway.

the non-return means may comprise a ratchet.

The relocker pin may compnse an upper part and a separate lower part. Tn other words the relocker pin may be split into vo.

The upper part may have an axial end, adjacent the lower part, which slopes relative to the longitudinal axis of the outer locking hole within which it is located. Tn a similar manner the lower part may have an axial end, adjacent the upper part, which slopes relative to the longitudinal axis of the outer locking hole within which it is located.

The two axial sloping ends may have substantially corresponding angles of inclination such that they closely ht together within the outer locking hole.

Such a relocker pin may be formed by cutting a single pin into rtvo at an oblique ariglc to the longitudinal lcnigtTi of the pin. Other sliapcs arc cotiteniplated.

The upper part may be contigured to substantially jam in the outer and/or inner locking hole by at least partially toppling over.

This may occur because as the relocker pin is urged into the inner locking hole the lower part may rotate axially such that the corresponding slopes do not match as before. Alternatively or additionally, the pressure of the biasing means onto the upper part may thus push over the upper part such that its longitudinal axis is no longer parallel with the longitudinal axis of the inner and/or outer locking holes. This toppling may occur even if the lower part does not rotate.

The upper part may have a body and a rim projecting radially from the body.

This shape may he a "mushroom pin". The rim may assist in jamming the upper part within the outer and/or inner holes.

This jamming effect further may prevent the key pins from being moved upwards by the peaks of the key blade as the key is withdrawn from the keyway, thus preventing complete withdrawal of the key.

This feature also prevents the key from being "bumped" again so as to overcome the relocker pins in the second or third row of outer locking holes.

The biasing means within the second and third rows of outer locking holes may provide a greater force than the biasing means in the first row of outer locking holes.

The above and other characteristics, features and advantages of the present invenflon will become. apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the pnncip]es of the invention. This description is given for the sake of example only, without limiting the scope of the invention. Ihe reference figures quoted below refer to the attached drawings.

Figure 1 is a perspective view of a prior art rim or cylinder lock; Figure 2 is a cross-sectional side view of the lock of Figure 1; Figure 3 is a cross-sectional side view of a first lock according to the invention, through the second set of re-locking holes; Figure 4 is a cross-sectional side view through the relocking holes of a second lock according to the invention with the relocker pins in a first position; Figure 3 is the same view as Figure 4 with the relocker pins in a second position; arid Figure 6 is a cross-sectional front view of a third lock according to the invention.

The present invention will be described with respect to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Each drawing may not include all of the features of the invention and therefore should not necessarily he considered to he an embodiment of the invention. In the drawings, the size of some of the elements may he exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar den ents and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the tenns so used are interchangeable under appropriate circumstances and that operation is capable in other sequences than described or illustrated herein.

Moreover, the terms top, hottoni, over, under and the like in the description and the claims are used for descriptive nposes and not necessarily for describing relative positions. it is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other orientations than described or illustrated herein.

it is to be notice.d that the term "comprising", used in the claims, should not be.

inte.rpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to he interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or componen, or groups thereof. thus, the scope of the expression "a device comprising means A and 13" should not he limited to devices consisting only of components A and 13. It means that with respect to the present invention, the only relevant components of the device are A and B. 1 5 Reference throughout this spec cation to "an embodiment" or "an aspect" means that a particular feature, structure or characteristic described in connection with the embodiment or aspect is included in at least one embodiment or aspect of the present invention. Ihus, appearances of the phrases in one eniibodinncnit'', in an embodiment", or "in an aspect" in various places throughout this specification are not necessarily all referring to the same embodiment or aspect, but may refer to different embodiments or aspects. Furthermore, the particular features. structures or characteristics of any embodiment or aspect of the invention may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this

disclosure, in one or more embodiments or aspects.

Similarly, it should he appreciated that in the description various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Moreover, the description of any individual drawing or aspect should not necessarily be considered to be an embodiment of the invention. Rather, as the folloxving claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while sonic embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as xviii be understood by those. skilled in the art. For example, in the. following claims, any of the claimed embodimenta can be used in any combination.

Tn the description provided herein, numerous specific details are set forth.

However, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of

this description.

In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, 1 5 coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intennediate value of said parameter, lying bertveen the more preferred and the less preferred of said alternatives, is itsclf preferred to said less preferred valuc and also to cacl value lying between said less preferred value arid said intermediate value.

The use of the term "at least one" may mean only one in certain circumstances.

The principles of the invention will now be described by a detailed description of at least one drawing relating to exemplary features of the invention. It is clear that other arrangements can be configured according to the knoxvledge of persons skilled in the art without departing from the underlying concept or technical teaching of the invention, the invention being limited only by the terms of the appended claims.

Tn Figure 1 a known cylinder lock 10 is shown comprising a cylinder housing 21 and a cylindrical plug 30 inserted into a socket provided in the housing 20. The plug 30 includes a keyway 40 for accepting a key to lock and unlock the latch (not shown). Tn use and with the correct key inserted into the keyway 40, the plug 30 may rotate within the socket of the housing 20 thus tuniing the connecting bar 50. This, in tuni, acts on the latch of the lock @iot shown) such as a bolt used in a typical door lock to retract and extend the bolt into a staple.

S

The cylinder housing 20 includes holes 60 for the locking pins will he described in more detail below. These holes 60 may he visible on the outer surface of the housing 20 because this is typically where they arc inserted.

A retaining means (not shown) may be used to retain the locking pins in the holes 60.

The view in Figure 1 shows the keywav having been rotated from the vertical.

in Figure 2, a key 70 with a key blade 80 has been inserted into a keyway of a pg 30. The peaks 90 and troughs 100 of the key 70 are visible.

After inserting the key 70 the key pins 110 in the inner row of locking holes 110 will rest in the troughs 100. the driver pins 140 in the outer row of locking holes 130 are urged downwardly by the springs 150. thus the driver pins 140 will be located across the shear line 44, which is the zone at which the outer surface of the plug 30 meets the inner surface of the socket of the housing 20.

in this situation (not shown), the plug 30 cannot he rotated in the housing because at least one of the driver pins 140 will be straddling the shear zone 44.

however, the figure shows what occurs when a bump key 70 is used. The key has been banged into the keyway such that the peaks 90 have urged the key pins 120 upwardly. Ihis urges upwardly thc driver pnis 140. For a rjioruent the key pins 120 and driver pins 140 will he as shown in Figure 2 such that the plug 30 can he rotated within the housing 20.

it will be noted that the peaks 90 on the key 70 are relatively low. It will also be noted that the key pins 120 have different lengths to suit the correct key for the lock, it may be that the driver pins 140 are also of differing lengths (not shown) to suit the correct key for the lock.

Using the hump key 70 the plug 30 and keyway 40 may he rotated from the initial 12 o'clock position shown in Figure 6 either clockwise or anticlockwise. In this way, without a reloeker feature, the lock could he unlatched and the key withdrawn hack at the 12 o'clock position.

I however, if the key is rotated to either of the reloeker positions (approximately 2 o'clock and 10 o'clock in Figure 6, the following situation occurs.

The springs 130 are shown extending to almost the outer perimeter of the cylinder housing 20. However, they may not extend as far as shown. Also, means of preventing the springs from extending, or falling out, from the holes 130 may he provided. For instance, plugs may be used.

With reference to Figure 3, the inner locking holes 110 will become coaxial with the second or third row of outer locking holes 230. \Vhen this happens the springs 250 provided in these outer locking holes 230 will urge relecker pins 240, located towards the base of the outer locking holes, into the inner locking holes 110 in the plug 30. If the correct key 70 had been inserted, the key pins 120 located in the inner locking holes would not allow the relocker pins 240 to enter the inner locking holes. This means that the plug 30 can continue to be rotated in the housing 20. However, if a bump key has been used the springs 250 will push the relocker pins 240 into at least one inner locking hole 110 such that the relocker pin will straddle the shear zone 44. This will prevent further rotation of the plug 30 in the housing 20.

This is the situation as shown in Figure 3.

Ilowever, as previously discussed, there is the possibility that the key is "bumped" again to overcome this relocking. Also, the key may be removed even if not bumped again.

In Figure 4avariation of the second or third row or outer locking holes 330 is shown. In this vcrsion, these outcr liules llavc a srnallcr width, smaller tlian thu key pins' width. This prevents the key pins 120 from passing above the shear zone 44. This is effected because as the key is withdrawn from the keyway the peaks 90 and troughs will move the key pins 120 up and down. there is likely to be at least one key pin which is longer than the distance betueen the top of a peak 90 and the shear zone 44. Ordinarily the key pin 120 would enter the outer locking hole 130, 230 briefly allowing the key to he withdrawn. However, by making the outer locking hole 330 have a smaller width the key pin 120 cannot enter. This will prevent the peak 90 from passing underneath the key pin 120 thus preventing the key's complete withdrawal.

Another possibility, which may be mutually exclusive from the feature of the reduced \vidth described above, is that the relocker pin comprises two parts 340A, 340B. A lower part 340A is shown comprising a pin having a cylindrical base and an upper cone 341. The upper part 340B is shown comprising a tnushroom pin having its axial base 343 partially cut off at a sloping angle to approximately match the angle of the sloping surface of the cone on the lower part 340A.

The mushroom pin is a sinailar shape to a traditional cotton reel in that it has a cyhndrica] body and an upper and lower nm which projects radially away from the body.

Tn Figure 4, the plug 30 is in such a position that the inner locking holes 110 are not adjacent the outer locking holes 330.

Tn Figure 5, the inner locking holes 110 have been moved so that they are now adjacent and coaxial with the second or third outer locking holes 330. the spring 350 has urged the upper part 34013 and thus the lower part 34013 of the relocker pin towards the inner locking hole 110.

This movement has had the effect that the upper part 340B has moved laterally TO and downwardly within the outer locking hole 330. this naovement is aided by the sloping surface of the upper part 34013 and the cone on the lower part 340A interacting.

The lower partial rim 347 of the upper part 34013 has descended into the inner hole 110 and has caught under the edge 348 of the upper hole.

Tf the key pin 120 is now urged upwards, by the key being removed, the upper part 34013 will become jammed in the outer hole 330 if it has not already become jammed. For instance an upward movement of the key pin 120 will push the lower part 340A upwards which will rotate the upper part clockwise, as shown. the upper art naay become jarlirTled in thc outer hole. With the upper part 3406 jarnied in tiic outer hole 330, the key pin 120 cannot move upwardly and thus the key cannot he completely withdrawn from the keyway. Also, the lower part 340A is straddling the shear zone 44 which prevents the plug from further rotation within the housing 20.

The sloping surfaces may not be corresponding in that the upper and lower parts may have axial ends which slope at different angles from one another. this naay further aid the movement of the upper part.

The lower part 340A may also include a lower axial sloping surface to promote the possibility of it moving laterally within the hole, thus further jamming the relocker parts 340A, 34(13 in the inner and/or outer locking holes.

The lower part 340A may have a different shape to that shown. For instance it may have an "L shape".

Other means of jamming the relocker pin in the outer hole, or at least preventing it from moving axially away from the plug, are contemplated such as the use of any one or more of a ratchet, barbs, and pivotable arms located on the axial side(s) of the relocker pin/parts. For instance, the second and third rows of outer holes may he Ii tapped to include screw threads. The relocker parts/pins may include appropriately ang'ed serrations on their sides which allow them to move towards the inner row of heAes under pressure from the biasing means, but prevent them from moving upwards away from the inner row of heAes.

Figure 6 shows the initia' outer ocking hedes 130 with the driver pins 140 being urged by the springs 150 and thus urging the key pins 120 towards the plug 30. No key is present and thus it can be seen how the driver pins 140 straddle the shear zone 44 between the p ug 30 and housing 20.

The relocker positions are shown as the second and third rows of outer locking holes 230. In this instance, the second and third outer holes 230 are shown having the same width as the inner holes 110.

Each of the second and third outer holes 230 includes a relocker pin 240 and a biasing means 250 urging the relocker pin 240 towards the plug 30.

Claims

(:LAIMS 1. A lock compnsing a housing including a secket and a plug inside the socket, the plug including a keyway for accepting a key, the lock contigured such that only with a correct key inserted into the kevway is the plug rotatable within the housing, the. housing further including a first row of at least one outer locking holes extending radially away from the circumference of the socket, at least one of the first row of outer locking holes including a first driver pin located therein, the first driver pin being moveable axially within the at least one outer locking hole in the first row, and a first biasing means for axially urging the first driver pin towards the plug, the plug comprising a row of at least one inner locking holes extending radially to the circumference of the plug being arranged coaxially with the first row of outer locking holes with the plug in a first rotational position relative to the housing, wherein at least one inner locking hole includes a key pin configured to he axially moveable therein with a key inserted into the keyway, the housing further comprising a second row of at least one outer locking holes extending radially to the circumference of the socket, at least one of the second row of outcr locking holes including a relocker pin located therein, the relocker pin being rnoveable axially within the at least one outer locking hole in the second row, and a second biasing means for axially urging the relocker pin towards the plug, wherein the axes of the first and second rows of outer holes are located distant from one another around, and in the same plane as, the circumference of the plug.
2. The lock of claim 1, wherein the housing further comprises a third row of at least one outer locking holes extending radially to the circumference of the socket, at least one of the third row of outer locking holes including a relocker pin located therein, the relocker pin being moveable axially within the at least one outer locking hole in the third row, and a third biasing means for axially urging the relocker pin towards the plug, wherein the axes of the first, second and third rows of outer holes are located distant from one another around, and in the same plane as, the circumference of the plug.
3. The lock of either one of claims 1 and 2. wherein with the plug in a second or third rotational pos1flot relative to the housing the row of inner locking holes is coaxial with the second or third row of outer locking holes such that the relocker pin is urged at least partially into the at least one inner locking hole when an incorrect key is present in the keyway, thus preventing the plug from further rotation relative to the housing.
4. The lock of any preceding claim, wherein any of the first, second and third rows of outer locking holes comprises more than one socking hole, and the ends of these outer locking holes adjacent the plug are arranged substantially rectilinearly in rows parallel to the rotational axis of the plug.
5. the lock of claim 4, wherein the row of inner locking holes comprises more thim one locking hole, and the ends of these inner locking holes adjacent the plug are arranged substantially rectilinearly in a row parallel to the rotational axis of the plug.
6. the lock of any preceding claim, wherein at least one of the second or third rows of outcr locking holes is configured to prevent the kcy pin frorri eritenrig it as an incorrect key is pulled axially away, along the keyway, from the plug.
7. The lock of claim 6, wherein the at least one of the second or third rows of outer locking holes being configured to prevent the key pin from entering it as an incorrect key is pulled axially away, along the keyway, from the plug, has a radial width smaller than the radial width of the axially located corresponding hole in the first row of outer locking holes.
8. The lock of any preceding claim, wherein the relocker pin comprises non-return means for preventing the relocker pin From moving axially away from plug.
9. The lock of any preceding claim, wherein the relocker pin comprises an upper part and a separate lower part.
10. The lock of claim 9, wherein the upper part has an axial end, adjacent the lower part, which slopes rdative to the longitudinal axis of the outer locking hole within which it is located.
11. The lock of either one of claims 9 and 10, wherein the lower part has an axial end, adjacent the upper part, which slopes relative to the longitudinal axis of the outer locking hole within which it is located.
12. The lock of claim 11 wherein the two axial sloping ends have substantially It) corresponding angles of inclination such that they closely ht together within the outer locking hole.
13. The lock of any one of claims 9 to 12, wherein the upper part is configured to substantially jam in the outer locking hole and/or the inner locking hole by at least partially topphng over.
14. Ihe lock of claim 13, wherein the upper part has'a body and a rim projecting radially from the body.13. "lock substantially as hereinhefore described with reference to the Figures 3 to 6 of the accompanying drawings.