GB2556336A

GB2556336A - Improvements to lock cylinders

Info

Publication number: GB2556336A
Application number: GB1615890.9A
Authority: GB
Inventors: Jennings David; Mcloughlin John
Original assignee: UAP Ltd
Current assignee: UAP Ltd
Priority date: 2016-09-19
Filing date: 2016-09-19
Publication date: 2018-05-30
Anticipated expiration: 2036-09-19
Also published as: GB2556336B; GB201615890D0

Abstract

A double cylinder lock comprising first and second cores 5, 6, rotatable in cylinder portions 2, 3 either side of a cam 11; selectively coupled to the cam by actuators 13, 14 biased preferably by spring 16. If the cylinder is attacked and the outer cylinder 3 is snapped off then biasing means 16 moves the cam axially which releases a biased anti-tamper locking pin 30 to lock the cam and prevent rotation. Preferably the cam has an aperture 28 into which locking pin engages when the cam is biased axially upon breaking of the cylinder; normally the aperture is misaligned and the pin is biased radially into contact with a surface of the cam. Preferably there is a third actuator 15 which can be moved by insertion of an internal key (9, fig.7), the actuator 15 having an inclined surface 34 which upon axially movement retracts the locking pin and unlocks the cam allowing the cylinder lock to be unlocked from the inside.

Description

(54) Title of the Invention: Improvements to lock cylinders Abstract Title: Anti-tamper double cylinder lock (57) A double cylinder lock comprising first and second cores 5, 6, rotatable in cylinder portions 2, 3 either side of a cam 11; selectively coupled to the cam by actuators 13, 14 biased preferably by spring 16. If the cylinder is attacked and the outer cylinder 3 is snapped off then biasing means 16 moves the cam axially which releases a biased antitamper locking pin 30 to lock the cam and prevent rotation. Preferably the cam has an aperture 28 into which locking pin engages when the cam is biased axially upon breaking of the cylinder; normally the aperture is misaligned and the pin is biased radially into contact with a surface of the cam. Preferably there is a third actuator 15 which can be moved by insertion of an internal key (9, fig.7), the actuator 15 having an inclined surface 34 which upon axially movement retracts the locking pin and unlocks the cam allowing the cylinder lock to be unlocked from the inside.

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Fig. 2

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Fig· 4

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Fig· 5

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Fig. 7

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Fig. 9

IMPROVEMENTS TO LOCK CYLINDERS

The present invention relates to lock cylinders, commonly called eurocylinders, that are used in conjunction with locking mechanisms such as mortise locking mechanism for doors and other similar closures.

The lock cylinder is designed to operate a rotatable cam with a projecting cam lever that bears against a spring-loaded latch or similar portion of the locking mechanism to open it when the cam is rotated. Rotation of the cam is usually accomplished either via a pin tumbler lock mechanism that requires a key to operate or via a thumb-turn mechanism. Lock cylinders may incorporate two pin tumbler lock mechanisms on opposite sides of the cam so that keys are required to open a door from both sides. Alternatively, lock cylinders may incorporate a tumbler lock mechanism on one side of the cam and a thumb-turn mechanism on the opposite side of the cam, the former typically being accessible from the exterior side of a door and the latter from the interior side. In both cases, the cam is usually selectively connected to one or other of these mechanisms by a biased clutch arrangement that is axially slidable between two positions wherein it is engaged by one of these arrangements to rotate the cam as the key or thumb-turn is rotated but is not engaged by the other of the arrangements in order that it can rotate freely relative thereto.

A problem with known locks of this type is that they can be broken into with relative ease to gain access to the locking mechanism. The application of force via a tool from the exterior side of the lock cylinder can break off part of it on one side of the cam allowing the cam to be rotated or removed to leave the locking mechanism exposed.

The object of the present invention is to provide an improved lock cylinder that obstructs access to the locking mechanism if the lock is broken into.

According to the present invention there is provided a lock cylinder for a closure comprising a casing defining a longitudinal axis;

a rotatably mounted cam that is adapted to actuate an adjacent locking mechanism;

a first core rotatably mounted within the casing on one side of the cam;

a second core rotatably mounted within the casing on the opposite side of the cam to the first core; and a clutch arrangement adapted to actuate rotation of the cam and comprising a biasing means and first and second actuators that are rotationally engaged with the first and second cores respectively and that are each selectively capable of movement along said longitudinal axis between a first position wherein the actuator also rotationally engages the cam and a second position wherein it is not rotationally engaged with the cam, movement of the first actuator into its first position moving the second actuator into its second position and vice versa, and wherein in use the biasing means also acts should the lock cylinder be attacked and the second core and the second actuator removed to move the cam axially away from the first core in order to release a biased locking pin that then locks the cam against rotation relative to the remaining casing.

Preferably, a third actuator is provided that is movable against the force of the biasing means when the locking pin is locking the cam against rotation to push the locking pin out of engagement with the cam to permit rotation of the second core to rotate the cam. This enables the closure to be opened by rotation of the first core which is normally located on an interior side of the closure.

Preferably also, the locking pin is located in a bore formed in the casing.

Other preferred but non-essential features of the present invention are described in the dependent claims appended hereto.

The present invention will now be described by way of example with reference to the accompanying drawings, in which:Figs, l and 2 are perspective and plan views respectively of an embodiment of lock cylinder in accordance with the present invention;

Fig. 3 is a schematic perspective view of the interior of the lock cylinder shown in Figs, l and 2 but details of lock mechanisms forming part of the cylinder that are not relevant to the invention have been omitted for clarity;

Fig. 4 is a part longitudinal sectional view along the line IV-IV in Fig. 2 and again details of lock mechanisms forming part of the cylinder that are not relevant to the invention have been omitted for clarity;

Fig. 5 is an exploded view of Fig. 4;

Fig. 6 is a view similar to Fig. 4 but after part of a casing of the lock cylinder has been removed as would be the case following an attempted break-in;

Fig. 7 is a view similar to Fig. 6 but to an enlarged scale showing use of a key to open the remaining part of the lock cylinder;

Fig. 8 is an end view of a modified cam for use in a lock cylinder as shown in Figs. 1 to 7; and

Fig. 9 is a longitudinal sectional view along the line IX-IX in Fig. 8.

An embodiment of lock cylinder in accordance with the invention comprises a casing l with first and second cylindrical portions 2 and 3 between which is a gap in which a cam 4 is located centrally of the casing 1. The cylindrical portions 2 and 3 define a longitudinal axis along which are respectively located first and second lock cores 5, 6 on opposite sides of the cam 4 that comprise pin tumbler lock mechanisms. These mechanisms are conventional and comprise a keyway 7 and bores 8a housing key pins (not shown) movable when a key 9 is inserted into the keyway 7 to act on biased driver pins (not shown) located within corresponding bores 8b formed in a radially projecting part 10 of the casing 1 that spans its length. In other embodiments other lock mechanisms may be employed, for example wafer lock mechanisms.

Whilst the illustrated embodiment of lock cylinder shows first and second cores 5, 6 on opposite sides of the cam 4 that comprise pin tumbler lock mechanisms, other embodiments of lock cylinder in accordance with the invention may comprise a core 6 of a first pin tumbler lock mechanism on one side of the cam 4 and a core 5 of a thumb-turn mechanism on the other side of the cam 4. Such an arrangement will be familiar to those skilled in the art. In use, the core 6 of the lock cylinder is intended to be located on an exterior side of the door or closure and the core 5 will therefore be located on an interior side. It is therefore the core 6 on the exterior side of the cylinder that will be attacked should a break-in be attempted. It will be appreciated that the pin tumbler lock and thumb-turn mechanisms are conventional but the manner in which they interact with a clutch arrangement provided to be selectively connected to one or other of these mechanism with the cam 4 is the subject of the present invention and this will now be described.

As shown in Figs. 4 and 5, the cam 4 comprises a substantially hollow cylindrical body 11 with a radially projecting lever 12. The body 11 is rotatably mounted between the first and second cylindrical portions 2, 3 of the casing

1. Rotation of the body 11 moves the lever 12 so that in use it can bear against a spring-loaded portion of an adjacent locking mechanism with which the lock cylinder is operationally linked. Rotation of the body n is effected by means of a clutch arrangement that comprises four elements, namely first and second actuators 13, 14, a third actuator 15 and a biasing means 16 such as a compression spring as shown in the drawings. However, the third actuator 15 is only deployed in the event after the lock cylinder has been attacked, as described below.

The first actuator 13 takes the form of a drive bar 13 that is located within the hollow body 11 of the cam 4 and comprises two wings 17 that project radially outwards on opposite of the drive bar 13 and locate in keyways 18a formed in a projecting end 19 of the core 5 located in the first cylindrical portion 2 of the casing 1. This projecting end 19 is also located within the hollow cam 4. The third actuator 15 comprises a disc 20 with a radially extending leg 21 and is also located within the projecting end 19 of the plug 6. The leg 21 locates in the lower keyway 18a adjacent the projecting part 10 of the casing 1 and the disc 20 lies adjacent the end of the keyway 7 through the core 5 where it can be contacted on one side by the end of the blade of a key inserted therein. Bearing against the other side of the disc 20 is one end of the spring 16, the other end of which bears against an end of the drive bar 13 and may be accommodated in a hollow portion 22 thereof. An opposite face 23 of the drive bar 13 is formed into a projecting nose that locates through an aperture defined by an inwardly projecting flange or shoulder 24 on the cam 4. The drive bar 13 is preferably a close fit within the aperture defined by the shoulder 24 to thwart insertion of a tool between

5 them if the lock cylinder is attacked as described below.

The drive bar 13 is axially movable within the cam 4 but retained therein on the side of the core 6 by abutment of the upper wing 17 with the inner face of the shoulder 24. Located adjacent the face 23 of the drive bar 13 is the second actuator 14. This actuator 14 is located within a projecting inner end of the core 6 and will rotate within the cylindrical portion 2 of the casing 1 when the core 6 is rotated. The actuator 14 comprises cylindrical body with a projecting nose 25 that is capable of penetrating the aperture defined by the shoulder 24 of the cam 4. The actuator 14 also comprises a radially projecting leg 26 that locates in a keyway 18b formed in the projecting end of the core 6.

The shoulder 24 of the cam 4 is provided with a keyway 27 into which either the leg 26 of the second actuator 14 or the lower of the two wings 17 of the drive bar 13 can be selectively engaged against the force of the biasing means 16 by movement along said longitudinal axis. Engagement of the wing 17 or the leg 26 into the keyway 27 of the cam 4 places the drive bar 13 or the second actuator 14 into a first position wherein it is rotationally engaged with the cam 4 so that the cam 4 can be turned by the turning of the appropriate core 5 or 6.

Similarly, the leg 21 of the third actuator 15 is also capable of sliding into a cut-away portion of the cam 4 that forms a keyway 28 to accommodate the leg 21. This takes place when the drive bar 13 is moved into its first position to engage the cam 4. The keyway 28 is enlarged at its inner end to form a slot or circular aperture 29 into which a locking pin 30 can penetrate if the lock cylinder is attacked and lock core 6 broken away from the main body of the cylinder. This operation is described in more detail below. However, first the locking pin arrangement itself will be described.

The locking pin 30 is located in a radially extending bore 31 with respect to the cylindrical portion 3 in the radially projecting part 10 of the casing 1. The pin 30 is biased towards the cam 4 by a compression spring 32 that is retained by a plug (not shown) at the end of the bore 31. The bore 31 is located in the portion of the part 10 adjacent the cam 4. As shown in Figs. 3 and 4, under normal operation of the lock cylinder the pin 31 is retained within the bore 31 as it bears on the outer surface of the body 11 of the cam 4 and when the cores 5, 6 are in a locked condition the nose 33 of the pin lies just to one side of the aperture 29 in the cam 4. After the pin 31 has penetrated the aperture 29, as is described below and as shown in Fig. 6, it locks the cam 4 in position so that it cannot be turned to operate a latch of an adjacent lock mechanism. In addition, the locking pin 31 prevents significant axial movement of the cam 4 towards or away from the core 5. However, the pin 31 can be pushed out of engagement with the cam4 and back into the bore 31 to enable the core 5 to be unlocked by inward axial movement of the leg 21 of the third actuator 15. This occurs when a key 9 is inserted into the keyway 7 of the core 5, as shown in Fig. 7. The third actuator 15 is adapted to push the locking pin 31 out of engagement with the cam 4 by the provision of a chamfered surface 34 on the adjacent part of the projecting leg 21 that acts against a complimentarily shaped surface of the nose 33 of the pin 30. Once the pin 30 is no longer within the aperture 29 then the cam 4 is free to be rotated by rotation of the core 5 to act on the latch of an adjacent lock mechanism.

Operation of the lock cylinder under normal circumstances and after it has been attacked will now be described.

First, under normal circumstances the lock cylinder is arranged as shown in Figs. 3 and 4 with the core 6 on an exterior side of a door or closure and the core 5 on an interior side. The third actuator 15 is retained by the projecting end 19 of the core 5 in a first position wherein its leg 21 sits within the keyway 28 in the cam 4. However, by virtue of the biasing means 16 acting on the drive bar 13, which in turn acts on the second actuator 14, the second actuator 14 is retained in a second position such that its leg 26 is retained outside the keyway 27 at the other side of the cam 4. If a key 9 is inserted into the keyway 7 in the core 5, the tip of the blade of the key pushes the third actuator 15 towards the drive bar 13 and the biasing means will urge the drive bar 13 along the longitudinal axis to insert its lower wing 17 into the keyway 26 until its upper wing 17 impacts the shoulder 24 of the cam

4. The drive bar 13 is now in its first position wherein it is rotationally engaged with the cam 4 so that if the lock mechanism of the core 5 is unlocked so that core 5 can rotate, then the projecting end 19 of the core 5 will act to turn the drive bar 13 that will in turn act to turn the cam 4. It will be appreciated that movement of the drive bar 13 into this first position

- 8 moves the second actuator 14 away from the cam 4 so that when the cam 4 is rotated by the drive bar the second actuator 14 will remain unmoved. In the alternative, when a key is inserted into the keyway 7 in the core 6, the tip of the blade of the key will act to push the second actuator 14 inwards axially into a first position so that its leg 26 will enter the keyway 27 in the cam 4. At the same time, the second actuator 14 pushes the drive bar 13 towards the third actuator 15 against the force of the biasing means 16 into a second position wherein its lower wing 17 is no longer within the keyway 27. In addition, the third actuator 15 is also moved axially into a second position wherein its leg 21 is no longer within the keyway 28. Hence, when the lock mechanism within the core 6 is unlocked, the rotation of the core 6 will rotate the second actuator 14 that will in turn act to turn the cam 4. However, the drive bar 13 and the third actuator 15 will not rotate. It will be appreciated, therefore, that the clutch arrangement acts selectively to connect one or other of the cores 5, 6 with the cam 4 so that rotation of that core 5, 6 also rotates the cam 4.

In the unfortunate event that a break-in is attempted, it is usual for the perpetrator to attempt to break the lock cylinder with a view to being able to access the latch of an adjacent lock mechanism contained within the door. As a result of this it usual for the casing 1 to be provided with one or more weakened areas or sacrificial cuts lA in order that it breaks at predetermined positions that enables a security mechanism within the lock cylinder to be fired into action, In the present case, the weakened area lA of the casing 1 is provided so that most or the whole of the second cylindrical portion 3 can be broken away, as shown in Fig. 7. This means that the second core 6 and the second actuator 14 also fall away from the remaining components of the lock cylinder. As soon as this occurs, there is nothing to restrain the cam 4 and the drive bar 13 from the force of the biasing means 16, which acts to push the drive bar 13 and therefore the cam 14 axially away from the third actuator 15. When the cam 4 moves axially, the aperture 29 at the end of the keyway 28 moves into line with the end of the bore 31 enabling the locking pin 30 to be fired into the aperture 29 by the spring 32. The cam is now restrained. It cannot be significantly rotated or pushed back towards the core 5. The nose 23 of the drive bar 13 now projects further out of the aperture defined by the shoulder 24 of the cam 4 under the force of the biasing means 16 but is not restrained axially as it can be pushed back into the cam 4. This makes it hard to grasp using pliers, pincers and the like with the aim of breaking into the cam 4 as it tends to retract back into the cam 4. The nose 23 is also preferably conically shaped to make it harder to grasp using a gripping tool. Alternatively or in addition the nose 23 may also be provided with a hardened tip to thwart drilling. The hardened tip may comprise a hardened steel ball bearing that is embedded in the drive bar 13 at the end of the nose 23. Also, the width of the aperture defined by the shoulder 24 in the cam 4 is preferably sufficiently great that the drive bar 13 cannot be pushed into the cam 4 to expose the inner edge of the aperture as this would enable a tool to be inserted into the cam 4 with the aim of pulling it forwards away from the core 5. Also, the locking pin 30 is preferably made of hardened steel so that it will not snap readily if the cam 4 is attacked.

Modifications may also be made to the cam 4 with a view to thwarting an attack. As shown in Figs. 8 and 9, the edge of the aperture may be weakened by the removal of material to leave the aperture defined by thin sections 35 of material. These will tend to break off if a tool is inserted with a view to rotating the cam 4 or levering the cam 4 away from the remaining casing 1. Also, the corners of the thin sections 35 are preferably made sharp for the same reason. The edges 36 of the keyway 27 where it merges with the inner profile of the cam 4 may also be rounded to make them more difficult to be forcibly rotated by a tool.

Hence, the lock cylinder of the invention is designed to withstand attack. However, notwithstanding the foregoing, the lock cylinder is still capable of operating to allow opening of the door or closure from its interior side. This is usually now a requirement of such lock cylinders for reasons of safety. When in a condition as shown in Fig. 6, it will be appreciated that a key 9 can still be inserted into the keyway of the core 5, as shown in Fig. 7.

The tip of the blade of the key will then act to push the third actuator forwards against the bias of the biasing means 16 because the drive bar 13 is restrained from movement away from the core 5 by the abutment of one of its wings 17 against the shoulder 24 defined by the cam 4. When the third actuator 15 is moved, its leg 21 will be moved along the keyway 29 and the chamfered surface 34 will act against the nose 33 of the pin 30 to push the pin 30 back into the aperture 29. Once the body of the pin 30 is no longer within the aperture 29 then the core 5 can be rotated, which will also rotate the cam 4 to unlock the adjacent lock mechanism.

Claims

1. A lock cylinder for a closure comprising a casing defining a longitudinal axis;

a first core rotatably mounted within the casing on one side of the cam;

a second core rotatably mounted within the casing on the opposite side of the cam to the first core; and a clutch arrangement adapted to actuate rotation of the cam and comprising a biasing means and first and second actuators that are rotationally engaged with the first and second cores respectively and that are each selectively capable of movement along said longitudinal axis between a first position wherein the actuator also rotationally engages the cam and a second position wherein it is not rotationally engaged with the cam, movement of the first actuator into its first position moving the second actuator into its second position and vice versa, and wherein in use the biasing means also acts should the lock cylinder be attacked and the second core and second actuator removed to move the cam axially away from the first core in order to release a biased locking pin that then locks the cam against rotation relative to the remaining casing.

2. A lock cylinder as claimed in Claim l, wherein a third actuator is provided that is movable against the force of the biasing means when the locking pin is locking the cam against rotation to push the locking pin out of engagement with the cam to permit rotation of the first core to rotate the cam.

3. A lock cylinder as claimed in Claim 2, wherein the third actuator is adapted to push the locking pin out of engagement with the cam by the provision of a projecting leg that acts against a tip of the locking pin.

4. A lock cylinder as claimed in Claim 3, wherein the projecting leg of the

5 third actuator defines a chamfered surface that acts against a complimentarily shaped surface defined by the tip of the locking pin.

5. A lock cylinder as claimed in Claim 3 or Claim 4, wherein when the first actuator is in its first position the third actuator is also

10 rotationally engaged with the cam by engagement of its projecting leg in a first keyway defined by the cam.

6. A lock cylinder as claimed in Claim 5, wherein the first keyway has an enlarged portion that defines an aperture into which the locking pin

15 penetrates to lock the cam against rotation.

7. A lock cylinder as claimed in any of Claims 1 to 6, wherein the locking pin is located in a bore formed in the casing.

20

8. A lock cylinder as claimed in any of Claims 1 to 7, wherein the first actuator comprises a drive bar that is located on the longitudinal axis within the cam between the first and third actuators and that transmits the force of the biasing means between the first and third actuators.

9. A lock cylinder as claimed in Claim 8, wherein the drive bar comprises a first radially projecting wing that locates in a first keyway formed in a projecting end of the second core and that bears against an internal shoulder defined by the cam and a second radially projecting wing

3 0 that locates in a second keyway defined by the cam when the drive bar is in its first position.

10. A lock cylinder as claimed in Claim 9, wherein a nose of the drive bar projects into an aperture defined by the internal shoulder of the cam and is urged into contact with the second actuator by the biasing means.

11. A lock cylinder as claimed in Claim 10, wherein the second actuator comprises a radially projecting leg and when the second actuator is in its in its first position it is rotationally engaged with the cam by engagement of its projecting leg in the second keyway defined by the

10 cam.

12. A lock cylinder as claimed in Claim 10 or Claim 11, wherein in use when the second actuator is removed the biasing means acts on the drive bar that in turn acts on the internal shoulder of the cam to move

15 the cam axially away from the first core.

13. A lock cylinder as claimed in Claim 12, wherein in use after the cam has moved axially away from the first core the drive bar is capable of being moved relative to the cam against the force of the biasing

2 0 means.

14. A lock cylinder as claimed in any of Claims 10 to 13, wherein the wall of the aperture in the cam is defined by defined by strips of material.

25

15. A lock cylinder as claimed in any of Claims 10 to 14, wherein the nose of the drive bar has a conical shape and/or a hardened tip.

Intellectual

Property

Office

Application No: GB1615890.9 Examiner: Ben Munns