A DOUBLE CYLINDER LOCK

Abstract

 A cylinder lock comprises a cam for actuating the bolting means of a door; the cylinder lock further comprising two ends, a first end positioned on a first side of the cam and a second end position on a second side of the cam, substantially opposite said first end; wherein at least said first end comprises a keyhole which, when a key is inserted, actuates the cam to lock or unlock the bolting means of the door; wherein the lock further comprises a drive assembly for displacing said cam when a key is inserted, and a securing means which is displaceable, by said drive assembly, between a first position in which the securing means engages with the cam to prevent its movement, and a second position wherein the securing means disengages the cam to allow movement of the cam; whereby, in use, when a key is not present in the lock, the securing means is in the first position to prevent movement of the cam and thus the bolting means of the door.

Description

Field of the Invention

[0001] The invention relates generally to the field of locks and locking mechanisms and relates more specifically to cylinder locks and locking mechanisms.

Background to the Invention

[0002] The closest prior art known to the Applicant are cylinder locks and locking mechanisms for preventing unauthorised access through a doorway which comprise securing means for reducing the risk of unauthorised access through the doorway even when the cylinder lock is snapped.

[0003] Typically, a cylinder lock comprises two key entry points, one on the exterior side of a door and one on the interior side, and an associated bolt mechanism incorporating a number of bolts which extend, when the mechanism is locked, between the door and the frame surrounding the door. When a correct key is inserted into either the interior or exterior side of the cylinder lock, a cam within the lock can be actuated to move the or each bolt from a locked position to an unlocked position, and vice versa, thus allowing the door to be locked and unlocked.

[0004] Cylinder locks typically additionally comprise means for stopping unauthorised access through the door when a part of the cylinder lock, usually an exterior end, is snapped or otherwise detached from the remainder of the lock. Most current cylinder locks are provided with a sacrificial end portion provided at the exterior end of the lock which, when snapped, aims to prevent the cam inside from being actuated manually by a screwdriver or other lock-picking tool. However, burglars managed to circumvent these means and manually actuate the cam to unlock the door.

[0005] Some cylinder locks have been further developed by incorporating a securing means comprising a pin or the like which, under normal use, i.e. when the lock is not snapped, is suppressed and inactive. When the cylinder is snapped, the securing means, e.g. a locking pin, is fired to block movement of the cam into a position wherein the or each bolt of a bolt mechanism is unlocked. However, these mechanisms have also been shown, in practice, to be ineffective if a cylinder is snapped in a certain way, causing the securing means to remain inactive and thus allowing unauthorised access through a doorway.

[0006] Various examples and embodiments of these cylinder locks and securing means are known and each suffers from at least these known disadvantages. It is therefore an object of the current invention to provide an improved locking mechanism.

Summary of the Invention

[0007] In a first broad independent aspect the invention provides a cylinder lock comprising a cam for actuating the bolting means of a door; the cylinder lock further comprising two ends, a first end positioned on a first side of the cam and a second end position on a second side of the cam, substantially opposite said first end; wherein at least said first end comprises a keyhole which, when a key is inserted, actuates the cam to lock or unlock the bolting means of the door; wherein the lock further comprises a drive assembly for displacing said cam when a key is inserted, and a securing means which is displaceable, by said drive assembly, between a first position in which the securing means engages with the cam to prevent its movement, and a second position wherein the securing means disengages the cam to allow movement of the cam; whereby, in use, when a key is not present in the lock, the securing means is in the first position to prevent movement of the cam and thus the bolting means of the door

[0008] This configuration is particularly advantageous because it provides a cylinder lock which more effectively prevents movement of the cam and therefore unlocking of associated bolting means of a door when the cylinder is snapped. The securing means is implemented as soon as a key is removed from the keyhole so that however 'well' the cylinder may be snapped, i.e. regardless of how gently or accurately the cylinder is snapped, the securing means prevents movement of the cam without the correct key. The securing means is not reliant on a particular amount of force or direction of force to be implemented.

[0009] Preferably, said securing means comprises a spring and a pin which, in said first position, is urged by said spring to engage and prevent movement of the cam; and said drive assembly comprises a spool which engages said pin; wherein the spool is shaped and sized such that, when a key is inserted into or withdrawn from the lock, the spool is displaced to facilitate movement of the pin between said first and second positions. This configuration is particularly advantageous because the size and shape of the spool ensures that the pin is engaging and preventing movement of the cam when a key is absent from the keyhole. The provision of a spring, pin and spool also simplifies the configuration and minimises the risk that unauthorised access will be gained.

[0010] Preferably, the drive assembly at the first end of the lock comprises a top hat bush fixed to said cam and a drive dog assembly; said drive dog assembly comprising two or more digits which engage two or more corresponding recesses of said top hat bush, when a key is inserted into the lock, to actuate said top hat bush; and wherein the top hat bush further comprises a channel and said drive dog assembly comprises an elongate member which is located within and extends through said channel to engage and displace said spool when a key is inserted. The two or more digits and corresponding recesses ensure that the top hat bush and thus the cam are rotated in an improved manner to unlock and lock the bolting means of a door. The elongate member of the drive dog assembly and the channel of the top hat bush are particularly advantageous because the spool can be effectively displaced when a key is inserted at the first end.

[0011] Preferably, said drive assembly further comprises a shutter for shutting the aperture of the top hat bush when the elongate member of the drive dog assembly is removed from said aperture, such that, in use, if the elongate member is extracted from the aperture, the shutter shuts said aperture to prevent access to said cam. The shutter prevents access to the cam from the first end should the first end be detached from the remainder of the lock. If the first end of the lock is snapped from the rest of the lock, the elongate member of the drive dog assembly falls out of the aperture of the top hat bush and the shutter subsequently shuts the aperture.

[0012] Preferably, the rotator body comprises a recess which is arranged to receive the shutter when the elongate member of the drive dog assembly is removed from the channel of the top hat bush. This configuration is particularly advantageous because the shutter is bounded and guided by the recess when actuated. Security of the lock is also improved because it is made harder for the shutter to be moved once actuated.

[0013] Preferably the top hat bush and rotator body are formed of a single piece; and the shutter is contained within said single piece. This configuration further improves the structural integrity and security of the cylinder lock.

[0014] Preferably, wherein a first portion of the spool engages said pin when a key is not present in the lock and a second portion of the spool engages the pin when a key is inserted into the lock; wherein the first portion of the spool is greater in diameter than the second portion such that, when a key is inserted into the lock, the pin is disengaged from the cam under the force of said spring. The first portion of the spool having a greater diameter than the second portion ensures that the pin is pushed, against the force of the spring, into engagement with the cam when a key is absent from the keyhole. When a key is inserted, the spool is displaced so that the portion of lesser diameter engages the pin to allow the pin to disengage the cam. The configuration is thus simplified and the performance and efficacy of the lock is improved.

[0015] Preferably, a region of the spool which comprises said first and second portions has a parallelogram shape and the first portion of the spool comprises a corner of the parallelogram and the second portion of the spool comprises a side of the parallelogram adjacent the corner of the first portion. A parallelogram shape allows the lock to be used effectively from either the first, exterior end or the second, interior end with an equal effect on the pin. If a corner of the parallelogram region comprises the first portion, and sides adjacent the corner comprise the second portion (from either the first or second ends), the pin can effectively engage and disengage the cam when a key is inserted at the first end or when a key or actuator is used at the second end.

[0016] Preferably, the drive assembly at the second end of the lock comprises an internal plunger actuator which is accessible from the second end of the lock and which, in use, can be displaced to engage and displace said spool. An internal plunger actuator simplifies the configuration from the second end. Simplification at this end is possible because it is far less likely that the second end will be detached from the remainder of the lock, and unauthorised access to the cam via the second end is much less likely.

[0017] Preferably, said drive assembly further comprises one or more springs connected to said internal plunger actuator; wherein, in use, said internal plunger actuator is displaced against the or each spring such that, when pressure is released from the actuator, the actuator disengages said spool so that the spool may return to the first position in which the securing means engages and prevents movement of the cam. This configuration is particularly advantageous because the spool efficiently returns to its resting state when pressure is released from the actuator such that the securing means, i.e. the pin, engages and prevents movement of the cam when pressure is released from the actuator.

[0018] Preferably, the lock is configured such that, in the event that the first end of the cylinder is detached from the remainder of the lock, the lock is still actuable by a key. This configuration is particularly advantageous because, even if the first end of the cylinder is detached from the remainder of the lock, the lock can still be actuated by a person with a correct key.

Brief Description of the Drawings

[0019] In the drawings:

Figure 1A shows exterior views from the front and side of a preferred embodiment of the invention.

Figure 1B shows a cross-sectional view from the side along A-A of a preferred embodiment in the secured position.

Figure 1C shows a cross-sectional view from above along B-B of a preferred embodiment.

Figure 2 shows a perspective cross-sectional view of a preferred embodiment in the secured position.

Figure 3A shows a perspective cross-sectional view of a preferred embodiment in the secured position.

Figure 3B shows a perspective cross-sectional view of a preferred embodiment in the unsecured position.

Figure 4A shows a further perspective cross-sectional view of a preferred embodiment in the secured position.

Figure 4B shows a further perspective cross-sectional view of a preferred embodiment in the unsecured position.

Figures 5A to 5E show perspective, cross-sectional and side on views of a top hat bush in accordance with a preferred embodiment.

Figures 6A to 6C show side and cross-sectional views of a drive dog assembly in accordance with a preferred embodiment.

Figures 7A to 7D show side and front on views of a top hat drive pin in accordance with a preferred embodiment.

Figures 8A to 8F show perspective, cross-sectional, side and front on views of a rotator body in accordance with a preferred embodiment.

Figures 9A to 9C show views of a securing pin in accordance with a preferred embodiment.

Figures 10A to 10C show front, side on and enlarged sectional views of a spool in accordance with a preferred embodiment.

Figures 11A to 11E show perspective and cross-sectional views of a rotator drive dog in accordance with a preferred embodiment.

Figures 12A to 12C show side, front and cross-sectional views of an internal plunger actuator in accordance with a preferred embodiment.

Figures 13A and 13B show views of a pin hole shutter in accordance with a preferred embodiment.

Figures 14A to 14G show perspective, cross-sectional, side and front views of a rotator body in accordance with an alternative embodiment.

Figures 15A to 15F show side, perspective, cross-sectional and front views of a top hat bush and rotator body unit in accordance with an embodiment.

Figures 16A and 16B show front and cross-sectional views of a cylinder lock in accordance with an alternative embodiment.

Figures 17A and 17B show cross-sectional views from above and the side of a cylinder lock in accordance with an alternative embodiment.

Figures 18A and 18B show side and cross-sectional views of an alternative embodiment in an unsnapped configuration.

Figures 19A and 19B show side and cross-sectional views of the embodiment of Figure 8 in a snapped configuration.

Detailed Description of the Embodiments

[0020] A preferred embodiment of a cylinder lock is shown in Figure 1 and is referenced generally as 100. The lock 100 is improved in that a securing means is actuated whenever a key is removed from the lock to prevent movement of a lock cam inside the lock and therefore prevent unlocking of associated bolting means of a door (not shown) which extend between a door and a frame surrounding the door (also not shown).

[0021] The lock 100 comprises a cam 2 which is located between a first end 101 and a second end 102 of the lock 100. The first end 101 comprises a keyhole 103. When a (correct) key is inserted into the keyhole the cam can be actuated, via drive assembly 104, to unlock and lock the cylinder lock 100. The lock 100 also comprises securing means 6, preferably in the form of a pin, which is displaceable by the drive assembly 104 between a first position in which the securing means 6 engages the cam 2 to prevent its movement, and a second position in which the securing means 6 disengages the cam 2 to allow its movement.

[0022] In a preferred embodiment the securing means comprises a spring 13 and a pin 6 and the drive assembly 104 comprises a spool 7 which engages the pin 6 and which is displaced when a key is inserted to allow movement of the pin 6, from the first to the second position, and therefore movement of the cam 2.

[0023] In a preferred embodiment, the spool 7 comprises a region which is of a parallelogram shape and a corner of the region engages the pin in the first position, and the sides of the parallelogram adjacent the corner engage the pin in the second position. The side of the parallelogram which engages the pin in the second position depends on which end the spool is displaced, i.e. pushed from.

[0024] In a further preferred embodiment, the drive assembly at the first end 101 of the lock 100, i.e. the external lock barrel, comprises a drive dog assembly 14 and a top hat bush 1. The drive dog assembly 14 comprises two or more digits, or shorter pins, for engaging corresponding recesses of the top hat bush 1. The drive dog assembly further comprises a central elongate member, or central pin which passes through an aperture of the top hat bush 1 to engage the spool 7 when a key is inserted at the first end 101.

[0025] In a preferred embodiment, the lock 100 further comprises a shutter 10 which shuts the aperture of the top hat bush 1 in the event that the elongate member of the drive dog assembly is removed from the aperture of the top hat bush 1, e.g. if the first end 101 is detached from the remainder of the lock 100.

[0026] The second end 102 of the lock 100, i.e. the internal lock barrel, comprises an internal plunger actuator 9 for displacing the spool 7 and disengaging the securing means 6 from the cam from the inside of a doorway. In a preferred embodiment, the second end 102 also comprises a keyhole.

[0027] One or more springs are provided for displacing the spool such that the securing means 6 is in the first position when a key is absent from the keyhole of the first end 101 or if pressure is released from the internal plunger actuator 9 of the second end 102.

[0028] The lock 100 comprises the following in use:

In the resting state, as shown best in Figure 2, the pin 6 is held down against the spring 13 by the spool 7 so that it is engaged in a hole in the internal lock barrel.

[0029] As shown best in Figure 4B, when a key is inserted into the external lock barrel the end of the key will push the external drive dog assembly 14 forward so that the drive pins, i.e. digits of the drive dog assembly 14, engage in the pockets/recesses on the top hat bush 1. This action also advances the long pin, or elongate member, in the centre which will push the spool 7 against the spring 12 and allow the locking pin 6 to rise clear of the hole in the internal lock barrel due to the action of the spring 13. This action is all complete by the time the key is fully inserted and therefore ready to rotate. As the external lock barrel rotates the drive is transferred to the external drive dog assembly 14 due to the engagement of the ears in the slots in the lock barrel, the drive is transferred to the top hat bush 1 by the short pins which are engaged in the pockets on the bush. The top hat bush 1 is permanently engaged with the rotator body 5 via the pins 3 and so as the top hat bush rotates the rotator body and the cam 2 also rotate. In a preferred embodiment, which is shown in Figure 14, the rotator body 5 further comprises a recess 200 for receiving the shutter 10 which, in the cylinder lock 100, is located between the rotator body 5 and the top hat bush 1. Even more preferably, the recess 200 is substantially rectangular in shape, having a width slightly larger than the width of the shutter 10 so that the recess 200 guides the movement of the shutter 10 in the event the cylinder lock 100 is broken or tampered with, i.e. when the elongate member of the drive dog assembly vacates the aperture of the top hat bush 1. The recess 200 also makes it more difficult for the shutter 10 to be dislodged from the recess 200 after it has been actuated, improving the security of the cylinder lock 100 even when it has been broken and the front end of the lock 100 has been removed. Even more preferably, when the shutter 10 has a rounded end (see Figure 13B) the recess 200 has a rounded end to cooperate with the rounded end of the shutter 10 when the shutter 10 is actuated.

[0030] When the key is withdrawn all the components return to the resting state.

[0031] As shown best in Figure 3B, when a key is inserted into the internal lock barrel the end of the key will push the internal plunger 9 forward against the springs 4 until it contacts the inside face of the rotator drive dog 8 and then the two move forward together, against the spring 12. This action causes the drive dogs on the front face of the rotator drive dog 8 to engage in the slot on the back of the rotator body 5 and also the pin in the centre of the internal plunger 9 pushes the spool 7 forwards against the spring 11 and allows the locking pin 6 to rise clear of the hole in the internal lock barrel due to the action of the spring 13. This action is complete by the time the key is fully inserted and therefore ready to rotate. As the internal lock barrel rotates the drive is transferred via the ears on the side of the internal drive dog 8, which are in the slots in the lock barrel, to the rotator body 5 by the drive dogs on the face of the internal drive dog 8 and so to the cam.

[0032] When the key is withdrawn all the components return to the resting state.

[0033] In the event that the lock is broken then the external drive dog assembly will have fallen away with the external lock barrel, helped by the action of the spring 11, this will remove the long central pin, i.e. the elongate member, from the hole through the top hat bush 1 this allows the pin hole shutter 10 to drop behind the hole in the top hat bush 1 thus blocking the hole against the threat of a small tool or the recovered drive dog assembly 14 being inserted and moving the spool 7 to release the locking pin 6. This ensures that the rotator 5 remains locked in position relative to the internal lock barrel. Insertion of a key into the internal lock barrel will still be able to operate the lock as described above to effect an exit through the door.

[0034] In an alternative embodiment, the top hat bush 1 and rotator body 5 are integrally formed as a single unit 201, as shown in Figure 15. Actuation of the spool by the drive dog assembly 14 happens in the same way as described above, i.e. the elongate member of the drive dog assembly 14 located in the aperture of the top hat bush/rotator body 201 to displace the spool 7 and rotate the cam. However, in this embodiment, the security of the lock 100 is further improved because the rotator body 5 and top hat bush 1 are formed as a single piece. In this embodiment, the shutter 10 is located within the the single piece top hat bush/rotator body 201 and acts in the same way as described above in the event that the elongate member of the drive dog assembly 14 vacates the aperture of the single unit 201. In a preferred embodiment, the shutter 10 is located above the aperture of the unit 201 so that the shutter 10 is actuated, at least in part, via gravitational force if the elongate member is removed from the aperture. The unit 201 may further comprise one or more springs such that the shutter 10 is spring loaded. If spring loaded, it is not essential that the shutter 10 is located above the aperture of the unit 201. Locating the shutter 10 within the single unit 201 of the top hat bush 1 and rotator body 5 further improves the structural integrity and security of the cylinder lock 100. Preferably, the single unit top hat bush/rotator body 201 is comprised of stainless steel.

[0035] Figures 16 and 17 show views of an alternative embodiment, wherein the spool 7 and internal plunger 9 have an alternative shape and configuration to that of the first embodiment. In particular, the part of the spool 7 which engages the securing means 6 is not a parallelogram shape, but still comprises regions of greater and less diameter to actuate and suppress the securing means 6 in use. The internal plunger 9 has a recess for receiving an end of the spool 7 when the lock is used via the second end.

[0036] In an alternative embodiment, either where the rotator body 5 and top hat bush 1 are separate units or where the rotator body 5 and top hat bush 1 are formed as a single unit, the shutter 10 comprises a ball bearing 202. In a preferred version of this alternative embodiment, the bearing is spring-loaded such that, when the cylinder lock is broken or tampered with, the bearing 202 is urged into a position in which the bearing blocks the aperture of the top hat bush 1. In use, in the event that the cylinder is snapped, the ball-bearing 202 is fired to move from the position shown in Figure 18B to the position shown in Figure 19B.

Claims

1. A cylinder lock comprising a cam for actuating the bolting means of a door; the cylinder lock further comprising two ends, a first end positioned on a first side of the cam and a second end position on a second side of the cam, substantially opposite said first end; wherein at least said first end comprises a keyhole which, when a key is inserted, actuates the cam to lock or unlock the bolting means of the door; wherein the lock further comprises a drive assembly for displacing said cam when a key is inserted, and a securing means which is displaceable, by said drive assembly, between a first position in which the securing means engages with the cam to prevent its movement, and a second position wherein the securing means disengages the cam to allow movement of the cam; whereby, in use, when a key is not present in the lock, the securing means is in the first position to prevent movement of the cam and thus the bolting means of the door.

2. A lock according to claim 1, wherein said securing means comprises a spring and a pin which, in said first position, is urged by said spring to engage and prevent movement of the cam; and said drive assembly comprises a spool which engages said pin; wherein the spool is shaped and sized such that, when a key is inserted into or withdrawn from the lock, the spool is displaced to facilitate movement of the pin between said first and second positions.

3. A lock according to claim 2, wherein the drive assembly at the first end of the lock comprises a top hat bush and rotator body fixed to said cam and a drive dog assembly; said drive dog assembly comprising two or more digits which engage two or more corresponding recesses of said top hat bush, when a key is inserted into the lock, to actuate said top hat bush; and wherein the top hat bush further comprises a channel and said drive dog assembly comprises an elongate member which is located within and extends through said channel to engage and displace said spool when a key is inserted.

4. A lock according to claim 3, wherein said drive assembly further comprises a shutter for shutting the aperture of the top hat bush when the elongate member of the drive dog assembly is removed from said aperture, such that, in use, if the elongate member is extracted from the aperture, the shutter shuts said aperture to prevent access to said cam.

5. A lock according to claim 4, wherein the rotator body comprises a recess which is arranged to receive the shutter when the elongate member of the drive dog assembly is removed from the channel of the top hat bush.

6. A lock according to claim 4 or claim 5, wherein the top hat bush and rotator body are formed of a single piece; and the shutter is contained within said single piece.

7. A lock according to any of claims 2 to 6, wherein a first portion of the spool engages said pin when a key is not present in the lock and a second portion of the spool engages the pin when a key is inserted into the lock; wherein the first portion of the spool is greater in diameter than the second portion such that, when a key is inserted into the lock, the pin is disengaged from the cam under the force of said spring.

8. A lock according to claim 7, wherein a region of the spool which comprises said first and second portions has a parallelogram shape and the first portion of the spool comprises a corner of the parallelogram and the second portion of the spool comprises a side of the parallelogram adjacent the corner of the first portion.

9. A lock according to any of claims 2 to 8, wherein the drive assembly at the second end of the lock comprises an internal plunger actuator which is accessible from the second end of the lock and which, in use, can be displaced to engage and displace said spool.

10. A lock according to claim 9, wherein said drive assembly further comprises one or more springs connected to said internal plunger actuator; wherein, in use, said internal plunger actuator is displaced against the or each spring such that, when pressure is released from the actuator, the actuator disengages said spool so that the spool may return to the first position in which the securing means engages and prevents movement of the cam.

11. A lock according to any of the preceding claims, wherein the lock is configured such that, in the event that the first end of the cylinder is detached from the remainder of the lock, the lock is still actuable by a key.

Drawing