GB2639211A - Anti-snap cylinder lock - Google Patents

Abstract

A cylinder lock with a front region 105a and a central region has a cylinder core rotatable within a cylinder housing, and an immobilising member at least partially within a central region. The immobilising member 120 such as a plug or pin is moveable between a first position rotation of the core within the housing and a second position upon separation of the front region of the housing in which the immobilising member inhibits rotation of the cylinder core within the cylinder housing. Preferably a retention rod 230 in the front region retains the immobiliser pin 120 in the disengaged position; the retention rod 230 removed with the front region to release the immobiliser pin preferably under spring bias 225 to the blocking position in which it engages in a recess 220b in core extension 210 preventing rotation of the core. In an alternative arrangement (fig.5) the immobiliser may be held within the rotational core 210 and upon tampering releases to extend into the cylinder housing preventing rotation of the core.

Description

ANTI-SNAP CYLINDER LOCK

BACKGROUND

The present disclosure relates to locks, and more particularly to cylinder locks such as Euro cylinder locks. Cylinder locks may have failure modes which can be exploited by malicious attackers to open or bypass the lock. Such vulnerabilities may for example involve manipulating the locking mechanism to open the lock, or destructively damaging the lock to cause a failure of the locking functionality.

There is a desire for locks with reduced vulnerabilities, and a corresponding increased resistance to attack.

SUMMARY

According to one aspect of the present disclosure, there is provided a cylinder lock having a front region and a central region. The cylinder lock comprises a cylinder housing at least partially within the front region, and a cylinder core rotatable within the cylinder housing. For example, the cylinder core may be rotatable when the correct key is inserted, whereby to open the lock. An immobilising member is located at least partially within the central region. The immobilising member is moveable between a first position in which the cylinder core is able to rotate within the cylinder housing, and a second position in which the immobilising member inhibits rotation of the cylinder core within the cylinder housing. The immobilising member is responsive to separation of the front region from the central region to move from the first position to the second position. Thus, in an attack in which the front region of the lock is removed from the central region (for example by an attacker attempting to compromise the lock by destructively removing a front portion of the cylinder core from the rest of the lock), the immobilising member will move to the second position. In this second position, the cylinder core (which may for example be a portion of the core within the central region, such as a core extension) is inhibited from rotating and thus the lock cannot be opened. The lock is thus resistant to the above-described attack.

In an example, the immobilising member is completely within the central region. The immobilising member may thus remain within the central region of the lock even if the entire front region is destructively removed.

In an example, in the second position, the immobilising member substantially prevents rotation of the cylinder core within the cylinder housing. Such prevention means that the lock cannot be opened when the immobilising member is in the second position.

In an example, in the second position, the immobilising member engages with at least one of the cylinder core and a component configured to rotate with the cylinder core, to inhibit rotation of the cylinder core. This provides an effective way of inhibiting or preventing rotation of the core. The component configured to rotate with the cylinder core may be a core extension, the core extension being at least partially within the central region and physically coupled to the cylinder core. Thus, even if the cylinder core itself is removed, the immobilising member can engage with the core extension to prevent its rotation, thereby immobilising the lock in a locked configuration.

In one such example, in the first position, the immobilising member is entirely within one of: said cylinder or component configured to rotate with the cylinder core, and a non-rotatable component that is not configured to rotate with the cylinder core (which may for example be a housing component of the cylinder lock). Thus, in the first position, these components are able to move with respect to each other and the lock can be opened. In the second position, the immobilising member is located partially within said cylinder core or component configured to rotate with the cylinder core, and partially within said non-rotatable component. Thus, the immobilising component engages with both of these components, preventing them from moving relative to each other and thus preventing the lock from opening.

Alternatively or additionally, the immobilising member may be configured to move from the first position to the second position within a channel having a first part within said cylinder core or component configured to rotate with the cylinder core, and a second part within said non-rotatable component. This provides an effective mechanism for the immobilising member to move between the first and second positions.

The immobilising member may for example be at least one of an immobilising plug and an immobilising pin.

In an example, the immobilising member is maintained in the first position by a release member. The release member is configured to release the immobilising member from the first position upon separation of the front portion from the central portion. For example, the release member may mechanically engage with the immobilising member in the first position, and mechanically disengage from the immobilising member upon separation of the front portion from the central portion. The immobilising member is thus maintained in the first position during normal operation of the lock but, upon separation of the front portion (for example in an attack), it is released to the second position in which the lock is immobilised in a locked configuration. A spring may be configured to bias the immobilising member towards the second position, such that the immobilising member is moved into the second position by the spring upon its release.

The release member may comprise an engagement portion configured to engage with a correspondingly shaped receiving portion of the immobilising member. For example, the engagement portion may have at least one of a fork configuration, a rod configuration, and a staple configuration. The receiving portion comprises a corresponding recess in the engagement portion. The engagement member can thus securely engage with the receiving portion to maintain the immobilising member in the first position.

In an example, the release member is configured to separate, with the front portion, from the central portion. The release member may comprise an element of, or be mechanically coupled to, a component located at least partially within the front portion. For example, the release member may protrude from the front portion into the central portion. This provides an effective way for the release member to maintain the immobilising member in the first position within the central portion during normal operation, but release the immobilising member to the second position during an attack.

In an example, the release member is coupled via at least one of a magnetic coupling and a spring coupling with a corresponding member within the front portion, and configured to release the immobilising member upon severance of said magnetic or spring coupling. This provides another effective way for the release member to maintain the immobilising member in the first position within the central portion during normal operation, but release the immobilising member to the second position during an attack In an example, the cylinder lock comprises a reduced-strength boundary between the central portion and the front portion. The reduced-strength boundary may comprise at least one of one or more grooves, one or more holes, one or more cuts, and one or more regions of reduced material thickness.

In a further aspect, a cylinder lock comprises a cylinder housing, and a cylinder core rotatable within the cylinder housing. The cylinder housing comprises one or more drainage openings. Each of said drainage openings extends at least between an outer surface of the cylinder core within the cylinder housing and an outer surface of the cylinder housing. Said drainage openings provide at least part of one or more liquid-traversable paths between an interior volume of the cylinder core and an exterior of the cylinder housing. The one or more drainage openings may thus be configured to expel, via the one or more liquid-traversable paths, liquid directed into the interior volume of the core.

The drainage openings provide resistance against an attack modality in which liquid is injected into the cylinder core, for example into a central cavity for receiving a key. Such liquid may stress the internal components of the cylinder lock, and may furthermore be frozen (for example by application of a freezing agent such as an expanding gas). This weakens the structural integrity of the cylinder lock, which may increase the vulnerability to attacks such as that described above in which the front portion of the cylinder lock is destructively removed. The drainage openings provide improved resistance against such an attack, by allowing immediate removal of liquid introduced into the lock (for example before it can be frozen). For example, if the liquid is introduced under pressure, this pressure causes the liquid to be expelled from the cylinder housing.

Such drainage openings, further examples of which are described below, may be implemented in combination with the immobilising member discussed above. The drainage openings and immobilising member provide resistance against the same attack modality discussed above, and so exhibit a synergistic effect of significantly improved attack resistance when implemented in combination. In particular, the above-described freezing attack can freeze an immobilising member in place, preventing it from moving to the second position. The drainage holes can mitigate this, allowing the immobilising member to function as intended and thereby improving attack resistance.

In an example, the one or more drainage openings are located at an end of the cylinder housing nearest to a central region of the cylinder lock. For example, they may be substantially nearer to the end nearest to the central region than to the end furthest from the central region (i.e. the front end of the cylinder housing). This may advantageously improve the effectiveness of the draining, as the liquid cannot proceed further into the lock and thus is directed out of the drainage openings.

In an example, at least one of the one or more drainage openings is located within an upper-facing surface of the cylinder housing. This provides additional locations for drainage holes to be implemented, allowing a greater fraction of the cylinder housing to be provided with drainage holes, and thus provide improved drainage over examples in which the drainage openings are located only in a lower-facing surface of the cylinder housing. It is noted that liquid introduced in the attack modality described above is typically introduced under pressure and so upper-facing drainage openings may provide drainage substantially as effectively as lower-facing drainage openings.

The aforementioned upper-facing surface of the cylinder housing may be a portion of a surface of the cylinder housing facing at least partially upwards in an installed orientation of the cylinder lock. For example, the portion may be an upper portion of a substantially cylindrical cylinder housing wall.

In an example, at least one of the one or more drainage openings has a location in a wall of a cavity of the cylinder housing, the cavity being immediately adjacent to the cylinder core. The cavity may be located immediately below the cylinder core, in an installed orientation of the cylinder lock. For example, the cylinder core may be located within an upper portion of the cylinder housing, with the cavity being located within a lower portion of the cylinder housing. Said at least one of the one or more drainage openings may have said location in a sidewall of the lower portion of the cylinder housing. This provides another potential location for drainage openings, thereby increasing drainage performance and correspondingly increasing attack resistance.

In an example, at least a plurality of said one or more drainage openings are distributed radially around a longitudinal axis of the cylinder housing. Increased drainage may thereby be provided.

In an example, said one or more drainage openings comprise at least one of one or more substantially round holes, one or more substantially rectangular holes, and one or more elongate slots.

Each of said one or more drainage openings may have a diameter in the range of 1mm to 4mm. Alternatively or additionally, each of said one or more drainage openings has a depth in the range of 0.5mm to 5mm. This provides effective drainage whilst not compromising structural integrity of the cylinder housing.

As an example, said one or more drainage holes may together comprise at least half of a circumference around a longitudinal axis of the cylinder housing. Significant drainage is thus provided.

In an example, the cylinder core comprises one or more openings extending at least between the interior volume of the cylinder core and the outer surface of the cylinder core. Said openings of the cylinder core provide at least part of said one or more liquid-traversable paths between the interior volume of the cylinder core and an exterior of the cylinder housing. Effective drainage is thus provided from the interior volume of the cylinder core, which may for example be a key-receiving cavity of the cylinder core, to the exterior of the lock.

Further aspects, features and advantages of the present device will be apparent from the following description of examples, which is to be read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1A and 1B depict a lock according to an example.

Figures 2A to 2C depict longitudinal sectional views of the lock of Figures 1A-1B.

Figures 3A to 3C depict example releasing members in the lock of Figures 1A and 1B. Figure 4 depicts a lock according to an example.

Figures 5A to 5C depict longitudinal sectional views of the lock of Figure 4. Figures 6A to 6C depict example releasing members in the lock of Figure 4.

Figures 7 and 8 depict configurations of immobilising members according to examples.

Figures 9A and 9B depicts a lock having a cylinder according to an example. Figure 10 depicts drainage hole configurations in the lock of Figures 9A-9C.

DETAILED DESCRIPTION

Figure 1 depicts a cylinder lock (in this example a Euro cylinder lock) according to an example. The lock can be conceptually divided into three portions: a front portion 105a, a central portion 105b, and a rear portion 105c. The front portion 105a and rear portion 105b can receive a key to lock and unlock the cylinder lock. At least the front portion may be the target of an attack, for example because it is an exterior-facing portion of which at least the front surface is accessible to an attacker.

Figure 1B depicts a longitudinal section view of the cylinder lock of Figure 1. Visible components include a cylinder housing 110, a cylinder core 115 within the housing 110, and an immobilising member 120. The cylinder core is rotatable when the correct key is inserted. The immobilising member 120 is depicted in a position in which it does not inhibit the rotation of the core 115.

Figures 2A to 2C illustrate example functioning of the cylinder lock of Figure 1, in particular the function of the immobilising member 120, which in this example is an immobilising plug. In other examples, the immobilising member may have another configuration.

Figure 2A presents a side-elevation cross-section view of the cylinder lock in a normal operation configuration (i.e. exhibiting expected functionality prior to any malicious attack). Figure 2B provides a plan view of certain components of Figure 1.

The cylinder lock further comprises a central bridge 205 in the central portion 105b. A core extension 210 and coupling extension 215 provide an extension of the core 115 into the central portion 105b. The core extension 210 and/or coupling extension 215 may for example be mechanically coupled with, attached to, or part of at least part of the core 115. The core extension 210 and/or coupling extension 215 may thus rotate with the core, for example transferring the rotational motion of the core to the apparatus that is to be unlocked (such as a bolt of a door lock).

The immobilising plug 120 is located within a lower portion 220a of a channel (which may for example be termed a hole, or a cavity) within the central bridge 205. The channel continues to an upper portion 220b within the core extension 210. The terms "upper" and "lower" are labels of convenience expressed relative to the channel and do not imply any particular orientation or direction of the channel within the lock. In Figure 2A, representing normal operation in the absence of an attack, the immobilising plug 120 is located entirely within the portion of the channel 220a within the central bridge 205 and not the portion 220b within the core extension 210.

A spring 225 is positioned in the channel 220a beneath the immobilising plug 120. The spring (which may, in other examples, be another form of biasing member) biases the immobilising plug 120 towards the upper channel portion 220b. However, the immobilising plug 120 is held in place by a release rod 230. The release rod engages with a corresponding recess in the immobilising plug 120 to prevent it from being propelled by the spring 225 into the upper channel portion 220b. The release rod 230 is mounted within a bore of the cylinder housing 110 by way of a fixing pin 235. However, it will be appreciated that other ways of fixing the release rod 230 to the cylinder housing 110 may be implemented.

Figure 2C presents a longitudinal section view of the cylinder lock of Figure 2A and 2B, following a malicious attack in which the front portion 105a has been destructively removed. For example, the front portion may have been physically pulled from the central portion 105b by way of a clamp, wrench or other tool. Alternatively, it may have been cut from the central portion 105b. The lock may comprise a reduced-strength boundary between the front portion 105a and central portion 105b, for example one or more perforations, cuts, or areas of reduced material thickness, to encourage the front portion to separate in the depicted manner during an attack.

It can be seen in Figure 2C that the release rod 230, being retained with the front portion 105a by way of the fixing pin 235, has been removed from the immobilising plug 120 during the attack. The spring 225 has accordingly displaced the immobilising plug 120 from its initial position within the lower channel portion 220a into a position in which it is partially within the lower channel portion 220a and partially within the upper channel portion 220b.

As explained above, the lower channel portion 220a is within the central bridge 205 and the upper portion 220b is within the core extension 210. The central bridge 205 is a non-rotational part of the lock, within which the core extension 210 rotates to open the lock in normal operation. However, the presence of the immobilising plug 120 across both channel portions 220a, 220b physically prevents the core extension 210 from rotating within the central bridge. The lock is thus prevented from opening, even following a malicious attack in which the front portion 105a (including the core 115) is removed. The lock is thus resistant to such an attack. Conversely, in comparative examples which do not implement an immobilising member 120, the lock may be openable following removal of the front portion 105a because the core (including elements such as pins which prevent rotation absent insertion of the correct key) is no longer present.

The example of Figures 2A to 2C depicts the immobilising rod 120 only for preventing attacks against the front portion 105a. However, in other examples, a similar immobilising rod may be implemented alternatively or additionally to prevent attacks against the rear portion 105c.

Figures 2A to 2C depict an immobilising rod 230. However, other immobilising members may be implemented. Some examples are shown in Figures 3A to 3C. Specifically, Figure 3A depicts an immobilising staple 305a. Figure 3B depicts an immobilising rod 105b. Figure 3C depicts an immobilising fork 305c. In each example, the immobilising member 120 has a corresponding hole, groove or recess to engage with the release member 230.

An alternative example implementation of an immobilising member will now be described. Figure 5 depicts a longitudinal section view of a cylinder lock according to this example. The lock may externally appear similar to the previously-described lock as depicted in Figure 1A. The present lock comprises a housing 110 and core 115 which are substantially similar to those of the previous example. The lock also comprises an immobilising member 120, which is this example is an immobilising plug. However, the configuration of the plug is different from the previous example.

The response of the lock of Figure 5 to an attack will now be described with reference to Figures 5A to 5C.

Figure 5A presents a side-elevation cross-section view of the cylinder lock in a normal operation configuration (i.e. exhibiting expected functionality prior to any malicious attack). Figure 5B provides a plan view of certain components of Figure 1. Components functioning in substantially the same manner as the corresponding components depicted in Figures 2A to 2C are not described again here.

Analogously to the example of Figures 2A to 2C, a channel has a lower portion 220a within the central bridge 205 and an upper portion 220b within the core extension 210.

However, in this example, in normal operation (i.e. in the absence of an attack) the immobilising plug 120 is located within the upper channel portion 220b located within the core extension 210. The immobilising plug is not located within the lower channel portion 220a located within the central bridge 205. The spring 225 is located within the upper channel portion 220b and biases the immobilising plug 225 towards the lower channel portion 220a. The immobilising plug 120 is maintained in this position by the release fork 230, which performs an analogous function to the release rod 230 of Figures 2A to 2C. In a similar manner to that depicted in Figures 2A and 2B, the release fork 230 is mounted in a bore of the core 115 by way of fixing pin 235.

Figure 5C presents a longitudinal section view of the cylinder lock of Figures 5A and 5B, following a malicious attack such as that described above in which the front portion 105a has been destructively removed. In the same manner as the lock of Figures 2A to 2C, the lock may comprise a reduced-strength boundary between the front portion 105a and central portion 105b.

It can be seen in Figure 5C that, in the same manner as Figure 2C, the release rod 230 has been removed from the immobilising plug 120 during the attack. The spring 225 has accordingly displaced the immobilising plug 120 from its initial position within the upper channel portion 220b into a position in which it is partially within the lower channel portion 220a and partially within the upper channel portion 220b.

As for the example of Figure 2C, the lower channel portion 220a is within the (non-rotational) central bridge 205 and the upper portion 220b is within the (rotational) core extension 210. In a similar manner, the presence of the immobilising plug 120 across both channel portions 220a, 220b physically prevents the core extension 210 from rotating within the central bridge. The lock is thus prevented from opening, even following the attack. The lock is thus resistant to such an attack.

As for the previous example, the example of Figures 5A to 5C depicts the immobilising rod 120 only for preventing attacks against the front portion 105a. However, in other examples, a similar immobilising rod may be implemented alternatively or additionally to prevent attacks against the rear portion 105c.

Figures 5A to 5C depict an immobilising fork 230. However, other immobilising members may be implemented. Some examples are shown in Figures 6A to 6C. Specifically, Figure 6A depicts an immobilising fork 305a. Figure 6B depicts an immobilising stick 105b. Figure 6C depicts an immobilising staple 305c. In each example, the immobilising member 120 has a corresponding hole, groove or recess to engage with the release member 230.

As can be seen from the description above, the locks of Figures 2A to 2C, and 5A to 5C, function analogously with the difference being the initial position of the immobilising member 120 (and correspondingly, the respective positions of the spring 225, release member 230, and associated components. It will be appreciated that further configurations may be implemented for maintaining an immobilising member, to be released in an attack in which the front portion of the lock is removed. Two further examples will now be described with reference to Figures 7 and 8. For brevity, these depict only the configuration following an attack.

In Figure 7, the immobilising plug 120 was initially held within the core extension 210 by a sprung plunger 705 having a conical end that engaged with a corresponding recess in the immobilising plug 120. Following separation of the front portion 105a, the sprung plunger was able to move axially, being pushed in that direction by way of laterally transferred force from spring 225 as the immobilising plug 120 moves into the depicted position. In the depicted position, the immobilising plug 120 prevents rotation of the core extension in the same manner discussed above.

Figure 8 depicts a configuration analogous to Figure 7 in that the immobilising plug 120 was initially held within the core extension 210 by a plunger 805 having a conical end that engages with a corresponding recess in the immobilising plug. However, instead of being held in place by a spring during normal operation, the plunger 805 was held in place by a magnetic connection to a second magnet 810 in the front portion 105a. Following separation of the front portion 105a, the magnetic connection is severed and the plunger 805 can move axially. The plunger 805 is thus pushed in that direction by way of laterally transferred force from spring 225 as the immobilising plug 120 moves into the depicted position. In the depicted position, the immobilising plug 120 prevents rotation of the core extension in the same manner discussed above.

The attack described above may be augmented by the addition of liquid (in particular water) to the keyway, which is then frozen. This can reduce the structural integrity of the lock, as well as compromising the immobilising member described above by freezing it in place so that it is not free to move to the immobilising position when the front portion of the lock is removed. An approach for mitigating this will now be described, with reference to Figures 9 to 10. This approach may be implemented in combination with, or as an alternative to, the immobilising members described above.

Figure 9A depicts a cylinder lock 905, which may for example include an immobilising member as described above. The lock 905 includes a number of drainage holes in the cylinder housing, which are identified by arrows in Figure 9B. These drainage holes serve to immediately expel water that is injected into the keyway, before it can be frozen. This effectively mitigates the freezing attack modality described above.

Figure 9B depicts drainage holes around the circumference of the cylinder housing 110.

These include drainage holes 910 on an upper surface of the housing 110. These upwards-facing drainage holes are effective because the drainage does not rely on gravity: the water is injected into the keyway under pressure, and that pressure causes the water to be immediately expelled through the drainage holes 910.

Figure 9B also depicts a cavity 915 at a lower part of the cylinder housing 110, which leads to sideways-facing drainage holes 920 in sidewalls of the cylinder housing. This provides a further effective drainage hole location, which can provide drainage without compromising the structural integrity of the cylinder housing.

Figure 10 depicts multiple alternative configurations of drainage openings, including round and rectangular holes and slots. One skilled in the art will appreciate that these, and in particular the relative fraction of the housing circumference dedicated to drainage holes in combination with their locations, can be implemented to provide a trade-off between effective drainage and the structural integrity of the cylinder housing.

Examples have thus been described to illustrate the present concepts, in which attack resistance of a cylinder lock can be significantly improved. It will be appreciated that these specific examples are intended to illustrate some of the ways in which the present disclosure can be implemented, the scope of this being defined by the appended claims.

Claims (24)

1. CLAIMS: 1. A cylinder lock having a front region and a central region, the cylinder lock comprising: a cylinder housing at least partially within the front region; a cylinder core rotatable within the cylinder housing; an immobilising member at least partially within the central region, the immobilising member being moveable between: a first position in which the cylinder core is able to rotate within the cylinder housing; and a second position in which the immobilising member inhibits rotation of the cylinder core within the cylinder housing, wherein: the immobilising member is responsive to separation of the front region from the central region to move from the first position to the second position.
2. 2. The cylinder lock of claim 1, wherein the immobilising member is completely within the central region.
3. 3. The cylinder lock of claim 1 or claim 2 wherein, in the second position, the immobilising member substantially prevents rotation of the cylinder core within the cylinder housing.
4. 4. The cylinder lock of any preceding claim wherein, in the second position, the immobilising member engages with at least one of the cylinder core and a component configured to rotate with the cylinder core, to inhibit rotation of the cylinder core.
5. 5. The cylinder lock of claim 4, wherein the component configured to rotate with the cylinder core is a core extension, the core extension being at least partially within the central region and physically coupled to the cylinder core.
6. 6. The cylinder lock of claim 4 or claim 5, wherein: in the first position, the immobilising member is entirely within one of: said cylinder or component configured to rotate with the cylinder core; and a non-rotatable component that is not configured to rotate with the cylinder core, and in the second position, the immobilising member is located partially within said cylinder core or component configured to rotate with the cylinder core, and partially within said non-rotatable component.
7. 7. The cylinder lock of claim 6, wherein said non-rotatable component is a housing component of the cylinder lock.
8. 8. The cylinder lock of any of claims 4 to 7, wherein the immobilising member is configured to move from the first position to the second position within a channel having a first part within said cylinder core or component configured to rotate with the cylinder core, and a second part within said non-rotatable component.
9. 9. The cylinder lock of any preceding claim, wherein the immobilising member is at least one of an immobilising plug and an immobilising pin.
10. 10. The cylinder lock of any preceding claim, wherein: the immobilising member is configured to be maintained in the first position by a release member; and the release member is configured to release the immobilising member from the first position upon separation of the front portion from the central portion.
11. 11. The cylinder lock of claim 10, comprising a spring configured to bias the immobilising member towards the second position.
12. 12. The cylinder lock of claim 10 or claim 11, wherein the release member is configured to: mechanically engage with the immobilising member in the first position; and mechanically disengage from the immobilising member upon separation of the front portion from the central portion.
13. 13. The cylinder lock of claim 12, wherein the release member comprises an engagement portion configured to engage with a correspondingly shaped receiving portion of the immobilising member.
14. 14. The cylinder lock of claim 13, wherein the engagement portion has at least one of a fork configuration, a rod configuration, and a staple configuration, and wherein the receiving portion comprises a corresponding recess in the engagement portion.
15. 15. The cylinder lock of any of claims 10 to 14, wherein the release member is configured to separate, with the front portion, from the central portion.
16. 16. The cylinder lock of claim 15, wherein the release member comprises an element of, or is mechanically coupled to, a component located at least partially within the front portion.
17. 17. The cylinder lock of claim 15 or claim 16, wherein the release member protrudes from the front portion into the central portion.
18. 18. The cylinder lock of any of claims 10 to 14, wherein the release member is coupled via at least one of a magnetic coupling and a spring coupling with a corresponding member within the front portion, and configured to release the immobilising member upon severance of said magnetic or spring coupling.
19. 19. The cylinder lock of any preceding claim, comprising a reduced-strength boundary between the central portion and the front portion.
20. 20. The cylinder lock of claim 19, wherein the reduced-strength boundary comprises at least one of: one or more grooves; one or more holes; one or more cuts; and one or more regions of reduced material thickness.
21. 21. The cylinder lock of any preceding claim, wherein the cylinder housing comprises one or more drainage openings, each of said drainage openings extending at least between an outer surface of the cylinder core and an outer surface of the cylinder housing.
22. 22. The cylinder lock of claim 21, wherein said one or more drainage openings have a location at an end of the cylinder housing nearest to the central region.
23. 23. The cylinder lock of claim 21 or 22, wherein said one or more drainage openings are distributed radially around a longitudinal axis of the cylinder housing.
24. 24. The cylinder lock of any of claims 21 to 24, wherein said one or more drainage openings comprise at least one of: one or more holes; and one or more slots.