GB2442237A - A lock comprising a securing element receivable in a protruding part of the cylinder - Google Patents

Abstract

A lock 1 comprises a cylinder 2 within which a plug 3 is rotatably mounted, the plug being arranged to receive a key 4 to enable manual rotation of the plug in direction 1R. The lock further comprises a case 5 which houses at least a part of a locking mechanism 6, the cylinder protruding from the case. The protruding part has a formation 10 to receive a securing element 11 to secure the lock in place from outside the case. The formation 10 may be a hole through the cylinder, the securing element passing through the hole. The hole may be threaded and the securing element may be a self-tapping screw. The lock may comprise a further securing element 13 arranged to be within the case. The securing element may be received in a portion of the cylinder which is not penetrated by the key. Also disclosed are a door a window having such a lock, and a drill jig (Fig. 5) for drilling a hole in such a door or window.

Description

Improvements in and relating to lock means for doors and windows The

present invention relates to lock means for doors and windows, and more particularly to key operated locks.

It is known to use key operated locks for doors and windows, where the lock comprises a rotatable plug and pm tumbler arrangement within a housing, the housing being retained to a deadlock mechanism or a sashlock mechanism and arranged so that mechanism may be operated between a locked state and an unlocked state by rotation or partial rotation of the rotatable plug only by a particular key. Examples of such locks are Euro Profile Cylinder locks and Oval Profile Cylinder locks. The term "cylinder" in this context and used hereinafter does not imply that the lock is geometrically cylindrical. Most locks of this kind have a part cylindrical shape extending radially from an axis of rotation of the rotatable plug when rotated within the cylinder by a said key. A benefit of such locks is that it is easy to change the lock when it is desired to require the use of a different key without removing or changing the mechanism. A problem with such known locks is that the cylinders may be broken and withdrawn from the door or window so as to permit the mechanism to be operated from the locked state to the unlocked state without the use of a key.

According to the present invention, there is provided a lock comprising a cylinder as hereinbefore defined and within which a plug which is rotatably mounted within the cylinder, the plug being arranged to receive a key, the key being arranged so as to enable manual rotation of to rotate the plug, and wherein the lock further comprises a case, the case housing at least a part of a locking mechanism, the cylinder protruding the case such that at least an axial portion of the cylinder protruding the case is not penetrated by the key when fully inserted, the lock having a means to receive a securing element at least partly through the axial portion of the cylinder, the cylinder being arranged to protrude the case, the protruding part having a means arranged to receive and inter-engage with a securing element, the securing element being arranged * : * to secure the lock in place from outside the case after the cylinder has been mounted to the case.

: A benefit of the invention is that a lock cylinder may be modified so as to enable it to be more securely retained, and hence an axial force applied to the cylinder is resisted so that an attempt to cause a part of the cylinder to be broken off sufficient to allow the lock mechanism to be operated without the key will be unsuccessful. p

Preferably the cylinder has a first axis through a centre of rotation of the plug, the key being arranged to be inserted into the plug in a direction parallel to the first axis, the cylinder being asymmetric about the first axis, the means having a second axis substantially along a centre line of the means, the second axis being substantially perpendicular to and offset from the first axis.

A benefit of the second axis being perpendicular to and offset from the first axis, is that it the means may be provided in a strong part of the cylinder and without affecting the operation of the locking mechanism.

Preferably the lock is arranged for fitting to a periphery of an opening leaf, and wherein the securing element is arranged to secure the cylinder within the periphery.

A benefit of the securing element securing the cylinder within the periphery is that it is hidden from view, and hence protected from interference by an intruder.

Preferably the lock further comprises a further means to secure the cylinder to the case, the further means having a third axis parallel to the second axis, the further means arranged to be within the case.

A benefit of the further means is that a positioning of the cylinder relative to the case may be maintained, and a benefit of the second and third axes being parallel to each other is that a location of the second axis may be determined from the location of the third axis.

Preferably the second and third axes are offset the same distance from the first axis.

A benefit of the second and third axes being offset the same distance from the first : * 25 axis is that when as in a typical installation the first axis is perpendicular to a face of * an opening leaf, such as an external face of a domestic door, the first axis will be *** 1* * horizontal, and hence an installer may accurately determine the location of the second axis, since it will be horizontally displaced from the third axis.

Preferably in an alternative embodiment of the invention, the second and third axes * are offset by different distances from the first axis.

A benefit of the second and third axes being offset by different distances from the first axis is that while the offset of the third axis may be determined by a need to conform to an industry norm or a standard, the offset of the second axis may be determined to suit a particular configuration of the cylinder and case. Such a particular configuration of the cylinder and case may be arranged for mounting to a particular configuration of a door or window, or may provide other benefits to the manufacturer p such as a particular overall dimension which is more easily obtained where the distance of the second axis from the first axis is different to the distance of the third axis from the second axis.

Preferably the means is a hole through the cylinder, and wherein the securing means is arranged to enter the means from one side and to protrude through the cylinder so as to extend beyond the cylinder on a far side.

A benefit of the means being a hole is that a through hole is easy to produce repeatably, and may be reliably made at a installation location using simple drilling equipment. A further benefit of the through hole is that the securing means may protrude through the hole and hence may engage with a supporting means, such as a portion of a door or window frame on both sides of the hole through the cylinder.

Preferably the means is a threaded hole through the cylinder and wherein the securing element is arranged to be retained to the cylinder by screwing into the means.

A benefit of the hole being threaded and the securing element having a mating thread form is that the securing element may reliably be retained to the cylinder such that it cannot easily be disengaged without the use of a tool, such as a screwdriver, when the door is in an open position.

Preferably the securing element is arranged so that it may be inserted into the means using a tool such as a screwdriver, but that the same tool cannot be used for its removal.

A benefit of the securing element being provided with a security head, is that it is more difficult for an unauthorised person to tamper with it. S...

Preferably the securing element is a self tapping screw . : A benefit of a self tapping screw is that where the hole has been drilled on site, it is * not necessary to thread the hole before inserting the screw. A further benefit is that the high degree of friction between the screw and the means is that the screw will not . : become loose during normal use of the door or window to which it is mounted.

Preferably the cylinder comprises a shape extending in the direction of the first axis away from at least one side of the case, the shape having a constant external cross-section profile, the profile having at least a radiused end.

More preferably the profile further comprises a first radiused end and a second radiused end, the first radiused end having a radius larger than the second, and the first radiused end having a centre substantially coincident with the first axis. Still more preferably there is a parallel sided portion joining the two radiused ends.

A benefit of the parallel sided portion is that the means may enter the cylinder at least partly through the parallel sided portion, and hence preferably a centre of the means lies on the parallel sided portion making it easier to start drilling a hole in the desired place without the drill wandering off centre.

Preferably there is also provided a door or window having the lock of this invention.

Preferably the lock is arranged to be mounted with the case extending from a peripheral surface into the frame of the door or window, the frame being provided with a hole in the peripheral surface, the hole having a fourth axis, the fourth axis being substantially co-incident with the second axis when the lock is mounted within the frame.

A benefit of the frame having a hole having a fourth axis which is co-incident with the second axis is that the securing element may be inserted through the means from outside the frame.

Preferably the door has an external face, the external face facing a direction of entry, the case having an external side facing the direction of entry, the means being adjacent the external side of the case.

A benefit of the means being on an external side of the case is that an attack on the cylinder is most likely to come from the external side, and hence the means may thus best provide protection from attack. S... * * S...

* Preferably there is also provided a drill jig for drilling the hole in a door or window * A benefit of the drill jig is that the reliability with which a said hole in the frame of the * 30 door or window may be greatly improved. Further, since the second axis is preferably perpendicular to the peripheral surface, a correct positioning of the hole may be obtained by using the drill jig.

Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:-Figure 1 is a perspective view of a lock having a means according to the invention shown mounted to an inwardly opening door drawn in broken lines; Figure 2 is a plan view from above of a section of a frame part of the door and the lock shown in Figure 1; Figure 3 is a view of the lock and door shown in Figure 1 in a direction along axis 1 Z of Figure 1, with the door shown in dotted lines; Figure 4 is a view of a lock having a means according to the invention mounted to a Figure 5 is a side view and Figure 5A is a plan view of a drill jig arranged for drilling the door of any of the above figures; Figure 6 is a partly sectioned side view of a cylinder for a lock according to a second embodiment of the invention; and Figure 6A is an end view of a cylinder for a lock according to third embodiment of the invention similar to that shown in Figure 6. * S * *.. ****

s From Figure 1 a perspective view of a lock 1 according to the invention shown *, * mounted to an inwardly opening leaf 100 of a door or a window drawn in broken lines. Leaf 100 swings open in the direction of arrow 1A and closed in the direction *:s.. 30 of arrow lB. The leaf 100 has an external face 101 facing to an outside space 112, and internal face 111 facing to an inside space 113, and a peripheral face 102, and an . : abutting face 103 having a recess 104 for receiving a draught seal.

The lock 1 comprises a cylinder 2 within which a plug 3 is rotatably mounted, the rotatable plug 3 being arranged to receive a key 4 having a length 1L, the key being arranged so as to enable manual rotation of the plug in the direction of arrow 1R. The lock further comprises a case 5 which houses at least a part of a locking mechanism 6, the cylinder 2 protruding the case 5 in a direction of arrow 1P and 1Q such that at least an axial portion 7 of the cylinder protrudes the case by a distance iS and is not penetrated by the key 4 when it is fully inserted by distance IL' into the plug such that stop 8 abuts an external face 9 of the plug 3. The lock is provided with a means 10 to receive a securing element 11 at least partly through the axial portion 7 of the cylinder.

The cylinder has a first axis 1X through a centre of rotation of the plug 3, the key 4 being arranged to be inserted into the plug in a direction 1K parallel to the first axis, the cylinder being asymmetric about the first axis, the means having a second axis 1 Y substantially along a centre line of the means 10. The second axis 1 Y is substantially perpendicular to and offset by distance iF from the first axis 1X.

Hence the second axis being perpendicular to and offset from the first axis, is that it the means may be provided in a strong part of the cylinder away from a bore housing the plug and without affecting the operation of the locking mechanism, which in this embodiment is a pin tumbler arrangement and is contained within the distance IL' so that the pins may be operated on by the key.

In another embodiment not shown here the tumblers could be discs or levers or any other suitable arrangement.

The lock 1 further comprises a further means 13 to secure the cylinder 2 to the case 5.

The further means 13 has a third axis 1 Z parallel to the second axis 1 Y, and the further means arranged so that when it is fully inserted into the cylinder a head 14 of the further means is substantially flush with a peripheral face 15 of the case 5. Hence the further means is substantially contained within the case 5.

The further means 13 provides a positive location of the cylinder 2 relative to the : ... case 5 such that axial movement of the cylinder in the directions of arrows 1P or 1Q is *::: :* resisted. Hence an operating cam 16 arranged to operate the lock mechanism within the case is maintained in the desired position relative to the case. Operation of the mechanism causes a bolt 17 to extend from the retracted position shown in Figure 1 so * as to securely retain the leaf 100 in a locked engagement with a fixed frame (not *:w: shown). The lock I shown in Figure 1 also has a handle 18 (for clarity only shown on the external face of the leaf) or handles which are pivotably mounted to a plate 19 which also provides an escutcheon to support and protect the cylinder 2. Operation of the handle causes latch bolt 20 to retract to allow an unlocked leaf to be opened.

In Figure 1, the securing means 11 and the further securing means 13 are shown partly inserted for clarity.

From Figure 2, a plan view from above of a section of a frame member 106 of the inwardly opening leaf 100 of a door or window and the lock 1 shown in Figure 1 it can be seen that the lock 1 is arranged for fitting to the peripheral face 102 of the opening leaf 100, such that the case 5 is mounted in a recess 105 within a frame member 106. Hence the securing element 11 when fully inserted into the means 10 is arranged such that a head 12 of the securing element is substantially flush with the peripheral face 102. The securing element securing the cylinder within the periphery is that it is hidden from view when the door or window is shut, and hence protected from interference by an intruder.

In Figure 2, the bolt 17 is shown extended. The frame member 106 comprises a reinforcing member 121 which in this example is a rolled galvamsed steel section, but could equally well be another material, such as extruded aluminium or a fibre resin composite. An intermediate wall 122 defines a rear surface of the recess 105 and channel sides 107 and 108 of the frame member 106 together with a hole 123 in a front wall 124 of the reinforcing member 121 define side surfaces of the recess 105.

Hence the case 5 extends from the peripheral surface 102 into the frame member 106 of the door or window leaf 100.

The frame member 106 has a hole 125 in the peripheral surface 102 extending into the frame member and through the front wall 124 at hole 126 and through the intermediate member 122 at hole 127, the hole having a fourth axis 2W, the fourth axis being substantially co-incident with the second axis 1 Y when the cylinder 2 of the lock 1 is mounted within the frame. Hence the securing element 11 may be inserted through the means 10 from an outside region 129 of the frame 106. In the embodiment shown in Figure 2, the securing element is arranged such that a pointed : ,*. end 128 passes through the hole 127 so as to improve the retention of the cylinder 2 to the frame 106.

In an alternative embodiment not shown herein, but similar to that described above with reference to Figures 1 and 2, the securing means 11' is of such a length that it enters the means 10, but does not pass through. Hence in this embodiment it can be ****** * seen that if extreme tensile force is applied to cylinder 2 along the direction of arrow * ** 2F, the securing element may possibly be deflected such that it abuts internal face 130 :.: * 35 of the frame member 106. Hence in this embodiment, the cylinder may be displaced in the direction of arrow 2F, but at least a substantial part of the axial portion 7 will be retained within the frame. Hence an intruder will be prevented from obtaining easy access to the lock mechanism within the case 5.

It will be noted in this alternative embodiment, in this instance of extreme tensile force, the cylinder may fracture at a weak point lying on centre line 3D within the case where the further means 13 penetrates the cylinder. However, this will not prevent all or a substantial part of the axial portion 7 being retained within the frame.

In a further alternative embodiment not shown herein, but similar to that described above with reference to Figures 1 and 2, the securing means 11"is of such a length that it passes through the cylinder, but does not extend sufficiently to pass through the intermediate wall 122. Hence when extreme tensile force is applied to the cylinder in the direction of arrow 2F, the securing means 11" will abut both internal face 130 and internal face 131. Securing means 11" will provide at least the same benefits as securing means 11', and in practice will provide the benefits of securing means 11 of preventing easy access to the lock mechanism, although an initial deflection will occur at a lower tensile force than that required to initially deflect securing means 11.

From Figures 1 and 2 it can be seen that the second axis 1 Y and third axis 1 Z are parallel to each other, and hence an person fitting the securing means may determine the location of the second axis by knowing the distance IH from the third axis.

Figure 3 is a view of the cylinder 2 and an indication of the relative position of the door frame member 106 as shown in Figures 1 and 2, viewed in a direction along axis 1Z of Figure 1. The second and third axes are offset the same distance iF from the first axis 1X, such that in a typical installation the first axis is perpendicular to a face of an opening leaf, such as the external face 101, the first axis will be horizontal, and hence an installer may more easily determine the location of the second axis 1 Y, since it is horizontally displaced distance 1H from the third axis IZ.

From Figures 1 and 3 it can be seen that the cylinder 2 comprises a shape extending in the direction of the first axis lx, the shape having a constant external cross-section profile 3S, the profile having a first radiused end 3L and a second radiused end 3J, the first radiused end having a radius larger than the second, and the first radiused end : having a centre substantially coincident with the first axis. There is a parallel sided * portion 3K joining the two radiused ends 3S and 3J. The second radius is smaller than distance 3M. Hence, the means 10 enters the cylinder at least partly through the parallel sided portion 3K, and hence a centre of the means 10 which is on axis 1Y lies on the parallel sided portion 3K making it easier to start drilling a hole in the desired place without the drill wandering off centre.

The cylinder 2 has a reduced cross section extending over portion 3E, and the further means 13 is retained in threaded hole 31 substantially at the centre of portion 3E on centre line 3D of the hole 31. Hence the reduced cross section is further reduced, creating a weak point along centre line 3D.

Excessive force applied axially in direction 2F or torsionally in direction of arrow IR when the cylinder is retained to frame member 106 only by the further means 13 engaging with the case 5 will cause the cylinder to fracture substantially along centre line 3D. When the cylinder fractures along centre line 3D, the cam 16 is no longer securely located between side portions 32 and 33 of the cylinder 2. Hence, an intruder may be able to manipulate the mechanism within the case 5 so as to unlock the door or window.

In the embodiment shown in Figures 1, 2 and 3 the means 10 is a threaded hole through the cylinder 2 and the securing element 11 is arranged to be retained to the cylinder by screwing into the means 10.

In an alternative embodiment not shown, the securing element is a self tapping screw and hence the screw is retained to the cylinder by the high degree of friction between he screw and the means. In a further variation of this embodiment, the screw is provided with a self drilling point, so that where the screw is of a length as shown in Figure 2, the screw may be inserted through the intermediate wall 122 without pre-drilling a hole.

From Figure 4 an outward opening wooden door 500 is shown with the opening leaf 400 fitted with a lock 401 according to the invention. The leaf 400 (which for clarity in this figure is shown without cross-hatching) is hingedly mounted on hinges 565 to a frame 560 which is fitted within an opening 570 in an external wall of a building. An external face 501 is facing a direction or space 512 from which an attempt may be made to make a forced entry, a lock case 405 has an external side 451 facing the direction of entry with a lock cylinder 402 protruding the lock case on at least the external side. A means 410 is provided through the cylinder such that a securing element 411 may be passed through the means adjacent to the external side of the : case. A key (not shown) is of such a length that a maximum penetration 40L of the key into a rotatable plug 403 which is arranged to rotate about axis 4X is such that a portion 407 of the cylinder is not penetrated by the key. The means 410 is arranged to be positioned within the portion 407 such that it does not interfere with a pin tumbler arrangement of the lock. The securing element 411 has a countersunk head 412 with a suitable means to enable the securing element to be inserted though the timber door and through the means 410. The head 412 is arranged to be flush with peripheral surface 502. The securing element 411 is preferably provided with a self drilling point 453 so that it can be inserted directly into the leaf and though the means. To -10 -assist with the insertion, a location jig may be provided similar to the drill jig shown in Figure 5.

Since the means is adjacent the external side 451 of the case 405 an attack on the cylinder or rotor applying an excessive tensile force in the direction of arrow 4F or torsional force in the direction of arrow 4T from the external side 512 is resisted by the means 411 which passes through the timber of the leaf 400. Hence the means ensures that at least an inside portion 470 between the means and the external side of the case 405 is retained between an attacker and a lock mechanism within the case, and hence an attempt to open the door without a key may be prevented.

A rosette 550 is retained by screws 552 and 553 passing though an internal escutcheon 551, the door leaf 400 and lock case 405. A purpose of the rosette is to protect a protruding portion 480 of the cylinder from a torsional attack.

The lock 401 has a latch 420 which is operated by insertion of a key into the rotor 403 so as to operate the mechanism within the case 405.

A further securing element 413 is arranged to secure the cylinder in a desired relationship with the case 405. Securing element 413 has a countersunk head 414 which passes through lock mounting plate 452.

Figures 5 and 5A show a drill jig 200 for drilling a hole in a door or window to provide the means 10 or 410. The drill jig is provided with holes 201 and 203 which are spaced a distance of 5H and 5J respectively either side of a spigot 202. The spigot 202 has a diameter of 5D such that it is a close fit in a hole in the case 5 that is arranged to receive further means 13. An extension 204 is provided for an installer to :. hold so as to keep the drill jig in a particular desired orientation when the spigot 202 is * engaged in a said hole arranged to receive further means 13. The distances 5H and 5J are such that the installer by using a suitably sized drill passing through the holes 201 or 203 will produce in a frame member such as member 106 shown in Figure 2, the holes 125, 126 and 127. The holes will be produced at the spacing 5H or 5J from the spigot, which is arranged such that the spacing 1H is obtained.

Figure 6 shows a partly sectioned side view of a cylinder 602 for a lock 600 according to a second embodiment of the invention. The lock 600 has a lock case 605 having side walls 653 and 654 with external faces 651 and 652 respectively, for clarity cross-hatching to indicate the sections has been omitted in this figure apart from the side walls 653 and 654. The cylinder 602 has a lateral portion 606 extending in a direction 6Y perpendicular to a first axis 6X along a length of the cylinder. A rotatable plug -11 - 603 is mounted within a bore 642 in the cylinder. The plug is arranged to receive a key 604 and 604' which is arranged to operate on a tumbler array 634 which comprises a plurality of pin tumblers 632 and 633 (only two labelled for clarity). In the arrangement of this embodiment, each tumbler array comprises five pairs of pins 632 and 633, each pair contained slidably within a bore 630, 630', 640, 640' (only four labelled for clarity) and urged in a direction towards the key by springs 631. The pins are of different lengths arranged so that when a key with a particular profile is inserted, each pair of pins 632 and 633 are positioned such that the two pins abut each other on a level with the bore 642 so that the rotatable plug may be rotated by means of the key. The tumbler arrays 634 with the pin tumblers and springs are contained within the lateral portion 606 within a tumbler portion 622 and 625 of the cylinder, the tumbler portion having an axial length 6L measured from an end 636 of the plug arranged to receive the key. The length 6L is in this embodiment shorter than a length 6P of the protrusion of the cylinder from the case 605.

The lateral portion 606 has a solid portion 623, 624 adjacent to and outside the sides 653/651 and 654/652 respectively of the case through which the cylinder protrudes.

The solid portions are also shown by cross hatching 620 and 621 to extend from and between the outside sides 651 and 652 respectively of the case 605 and a boundary 629 (only one instance labelled) of the tumbler portion 622 and 625 and a boundary 626 adjacent the bore 642 arranged to receive the rotatable plug.

A threaded through hole 610 and an unthreaded through hole 611 are shown within the solid portions 620 and 621. The holes 610 and 611 are means to receive and inter-engage with a securing element such as a threaded screw or a self tapping screw, similar to that shown and described as securing element 11 in Figure 1.

:..::: In an actual example of this embodiment, a further boundary 628 exists adjacent to a lower edge 607 of the cylinder.

: 30 In practice each boundary 626, 629, 628 is spaced slightly within the respective bounds of:-the plug bore 642; the inner-most pin bore 640, 640'; the lower edge 607.

The reason for this is to avoid a risk of the means 610 or 611 which are shown in this Figure as being adjacent to a boundary from affecting or damaging the feature alongside the boundary.

In practice, it has been found preferable that these boundaries are spaced within the bounds by a minimum distance of 1mm.

-12 -To obtain a reasonable tolerance on the positioning of the means and to facilitate the drilling of the means a preferred position for the means is as shown by means 611 which is spaced away from lower edge 607 the same distance as a further means 612 which is provided to enable thecylinder to be retained to the case 605.

From Figure 6A a cylinder 700 for a lock according to a third embodiment of the invention is shown. This is similar to the embodiment 600 shown in Figure 6, and has a rotatable plug 703 and a lateral portion 706 which contains a pin tumbler array 734.

The lateral portion 706 has substantially parallel sides 761 and 762. The cylinder has a cross section shape comprising a substantially constant profile with a first radiused end 766 and a second smaller radiused end 767.

A commercially available cylinder having such a shape is known as a Euro-Profile Cylinder.

In this embodiment 700 the means is a blind hole 710. The blind hole is shown in one side of the cylinder within the portion having the tumblers, the hole has a depth such that it does not penetrate a hole (corresponding to holes 630 of Figure 6) containing a tumbler. Since the blind hole is of such a depth 7D that it does not interfere with the tumbler array 734, and it may be positioned anywhere along the length of the portion of the cylinder protruding from the side of the case.

Hence in the embodiment of Figure 6A the blind hole 710 may be positioned anywhere along the portions corresponding to portions defined by 622, 623, 624, 625, 626 of Figure 6.

Hence the embodiment shown in Figure 6A may be particularly useful where it is not :. possible to position a through hole means in a solid portion of the cylinder.

:..::: The embodiment of Figure 6A provides a benefit of enabling modification of an existing lock cylinder to provide a means to receive and inter-engage with a securing *, * 30 means external to the lock case.

Although the hole 710 as shown is not threaded, it is preferred to provide a thread within the hole or to use a thread-forming securing means to enhance the inter- : engagement of the means and the securing means. *5* 5

Claims (20)

-13 - CLAIMS

1. A lock comprising a cylinder as hereinbefore defined and a plug which is rotatably mounted within the cylinder, the plug being arranged to receive a key to rotate the plug, and wherein the lock further comprises a case, the case housing at least a part of a locking mechanism, the cylinder being arranged to protrude the case, the protruding part having a means arranged to receive and inter-engage with a securing element, the securing element being arranged to secure the lock in place from outside the case after the cylinder has been mounted to the case.

2. A lock as claimed in claim 1, wherein the cylinder has a first axis through a centre of rotation of the plug, the key being arranged to be inserted into the plug in a direction parallel to the first axis, the cylinder being asymmetric about the first axis, the means having a second axis substantially along a centre line of the means, the second axis being substantially perpendicular to and offset from the first axis.

3. A lock as claimed in either one of claims 1 or 2, wherein the lock is arranged for fitting to a periphery of an opening leaf, and wherein the securing element is arranged to secure the cylinder within the periphery.

4. A lock as claimed in any of the preceding claims, wherein the lock further comprises a further means arranged to secure the cylinder to the case, the further means having a third axis parallel to the second axis, the further means arranged to be within the case.

5. A lock as claimed in claim 4, wherein the second and third axes are offset the same distance from the first axis.

6. A lock as claimed in any of the preceding claims, wherein the means is a hole * 30 through the cylinder, and wherein the securing means is arranged to enter the means * from one side and to protrude through the cylinder so as to extend beyond the cylinder S.....

* . onafarside. * **

7. A lock as claimed in any of the preceding claims, wherein the means is a threaded hole through the cylinder and wherein the securing element is arranged to be retained to the cylinder by screwing into the means.

-14 -

8. A lock as claimed in any of the preceding claims, wherein the securing element is a self tapping screw.

9. A lock as claimed in any of the preceding claims when dependent on claim 2, wherein the cylinder comprises a shape extending in the direction of the first axis away from at least one side of the case, the shape having a constant external cross-section profile, the profile having at least a radiused end.

10. A lock as claimed in any of the preceding claims when dependent on claim 9, wherein the profile further comprises a first radiused end and a second radiused end, the first radiused end having a radius larger than the second, and the first radiused end having a centre substantially coincident with the first axis.

11. A lock as claimed in any of the preceding claims when dependent on claim 2, wherein the cylinder further comprises a lateral portion extending in a direction perpendicular to the first axis along a length of the cylinder, and a plurality of pin tumblers arranged so that the rotatable plug is only rotatable by means of the key, and wherein the pin tumblers are contained within the lateral portion within a tumbler portion of the cylinder, the tumbler portion having an axial length measured from an end of the plug arranged to receive the key shorter than a length of the protrusion of the cylinder from the case, the lateral portion having substantially parallel sides.

12. A lock as claimed in claim 11, wherein the lateral portion further comprises a solid portion adjacent to and outside a side of the case through which the cylinder protrudes, the solid portion extending from and between the said outside side of the case and a boundary of the tumbler portion and a bore arranged to receive the

rotatable plug. ****

13. A lock as claimed in claim 12 when dependent on claims 6 or 7, wherein the hole is within the solid portion.

14. A lock as claimed in claim 12, wherein the means is a blind hole.

15. A lock as claimed in claim 14, wherein the blind hole is in one side of the cylinder within the tumbler portion, the hole having a depth such that it does not penetrate a hole containing a tumbler.

16. A door or window having the lock of any of the preceding claims.

-15 -

17. A door or window as claimed in claim 16 when dependent on claim 2, wherein the lock is arranged to be mounted with the case extending from a peripheral surface into the frame, the frame being provided with a hole in the peripheral surface, the hole having a fourth axis, the fourth axis being substantially co-incident with the second axis when the lock is mounted within the frame.

18. A door or window as claimed in claim 16, wherein the door has an external face, the external face facing a direction of entry, the case having an external side facing the direction of entry, the means being adjacent the external side of the case.

19. A drill jig for drilling the hole in a door or window as claimed in claim 17.

20. A lock substantially as hereinbefore described and with reference to the accompanying drawings.

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