GB2491585A

GB2491585A - Cylinder lock with clutch

Info

Publication number: GB2491585A
Application number: GB1109426.5A
Authority: GB
Inventors: Christopher Eric Belcher
Original assignee: UAP Ltd
Current assignee: UAP Ltd
Priority date: 2011-06-06
Filing date: 2011-06-06
Publication date: 2012-12-12
Anticipated expiration: 2031-06-06
Also published as: GB201109426D0; GB2491585B

Abstract

A cylinder lock comprising a casing with a rotable cam 7, axially sliding clutch 14 and a first rotor 9; the rotor has a hollow end with an inner annular groove (22, fig.10); the clutch moves between a first position in which it engages the cam and rotor, preferably by radial lugs (17, fig.10) of clutch engaging in slots (21, fig.10) of the rotor, and a second position where radial lug (17) of the clutch is located within the annular groove of the rotor such that the clutch is disengaged with the cylinder lock/rotor. Preferably it is a double cylinder lock with second rotor. In a first arrangement (fig.3) the clutch may be biased to a neutral position where neither rotor is disengaged; insertion of a key pushes the clutch such that clutch engages the keyed rotor and disengages with the other rotor. In a second arrangement (fig.8) the clutch may be biased into engagement with one rotor and disengagement with the other rotor; this is suitable where one cylinder may be operated by a thumbturn.

Description

IMPROVEMENTS TO CYLINDER LOCKS

The present invention relates to cylinder locks.

Cylinder locks are used in conjunction with a mortise lock case comprising a latching mechanism for locking doors, windows and other closures. The cylinder lock typically comprises a locking mechanism that operates a rotatable cam that when rotated bears against a spring-loaded portion of the latching mechanism to open it. Such locks may comprise single cylinder locks that allowing locking of a closures from one side only but usually the cylinder lock is a double cylinder that extends through the closure and is adapted so that it can be operated from both sides, at least one of the sides being key-operated with the other side being either key-operated or having a turn, for example a thumb turn knob. The cam is therefore positioned approximately mid-way along the cylinder of the lock and is selectively connected to locking mechanisms on both sides thereof that are either operated by keys or, in the case of turns, by turning a knob or lever.

The connection between the locking mechanism and the cam is effected by a clutch that is axially slidable along the cylinder between two positions wherein it is engaged by one of the lock mechanisms and turns the cam as the key or turn is rotated but is not engaged by the other of the lock mechanisms so that it can rotate freely relative thereto. In cylinder locks wherein both sides are key-operated, a key inserted fully into one side of the lock acts on the clutch to move it into the position wherein it engages the locking mechanism into which the key has been inserted. In cylinder locks with a turn, the clutch is usually biased into the position wherein it is normally engaged with the turn so that a user can open the closure by simply rotating the turn but can be slid into the other of the two positions by a key inserted into the other side of the lock.

A problem with known locks of this type is that they can be broken into and the latching mechanism actuated with relative ease. The application of force via a tool from the exterior side of the lock can break the cylinder and allow components of the locking mechanism to be removed to leave the latching mechanism exposed. In particular, the clutch typically comprises two wings that are held together by a central pin that passes through the cam. Such a clutch arrangement is weak and readily falls away to expose the latching mechanism if a core of the locking mechanism is pulled away.

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

According to the present invention there is provided a cylinder lock for a closure comprising a casing; a first core rotatably mounted within the casing and forming a locking mechanism therewith; a cam rotatably mounted adjacent one end of the first core; and a clutch adapted to actuate rotation of the cam and being axially slidable relative to the first core between a first position wherein rotation of the first core relative to the casing engages the clutch and rotates the cam and a second position wherein there is no engagement between the first core and the clutch on rotation of the clutch; characterised in that the end of the first core adjacent the cam is hollow and comprises an internal groove, and in that the clutch locates in the hollow end of the first core and comprises a projection such that in said first position the projection is engaged by the first core and the clutch is rotated when the first core is rotated and in said second position the projection aligns with the groove such that on rotation of the first core the first core rotates relative to the clutch.

Preferably, the hollow end of the first core defines a slot into which the projection locates when the clutch is in said first position whereby the clutch is rotated when the first core is rotated.

Preferably also, the clutch is spring-loaded.

Preferably also, a second core is rotatably mounted within the casing and the clutch comprises a bar which has at least one projection at each end thereof that locate respectively into slots defined by the first and second cores and which is axially slidable relative to the first and second cores such that when the clutch is in the first position relative to one of the cores it is also in the second position relative to the other core and vice versa.

Preferably also, the clutch is spring-loaded such that when there is no key inserted into either of the cores, it locates in a neutral position between the two cores wherein neither core is rotatable relative to the other.

Alternatively, the clutch is spring-loaded such that when there is no key inserted into the core, it locates in said first position relative to said first core and in said second position relative to said second core.

Preferably also, said first core is located in a portion of the casing intended to be located on an exterior side of the closure and the second core is located in a portion of the casing intended to be located on an interior side of the closure.

Preferably also, the clutch is adapted to be contacted by a tip of a blade of a key inserted into the first core and moved against the bias of the spring-loading on the opposite side of the core into its first position relative to the first core and into its second position relative to the second core.

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

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:-Figs. 1 and 2 are side and end views respectively of a first embodiment of cylinder lock in accordance with the present invention; Fig. 3 is a longitudinal sectional view along the line 111-111 in Fig. 2 showing components of the lock in a position adopted when a key (not shown) as been inserted therein on one side of the lock; Figs. 4 to 6 are transverse sectional views along the lines IV-IV, V-V and VI-VI in Fig. 1; Fig. 7 is a side view of a second embodiment of cylinder lock in accordance with the present invention; Fig. 8 is a longitudinal sectional view of the lock shown in Fig. 7 showing components of the lock in a position adopted when a key (not shown) as been inserted into an exterior side of the lock; Figs. 9 and 10 are respectively a side view and a longitudinal sectional view of a core forming part of either the first or the second embodiment of locks shown in Figs. 1 to 8; Figs. ii and 12 are respectively an end view and a longitudinal sectional view along the line XII-XII in Fig. ii of a cam forming part of a cam assembly of the first embodiment of lock shown in Figs. 1 to 6; Figs. 13 and 14 are respectively an end view and a longitudinal sectional view along the line XIV-XIV in Fig. 13 of a cam forming part of a cam assembly of the second embodiment of lock shown in Figs. 7 and 8; Figs. 15 and 16 are respectively a perspective view and a longitudinal sectional view of a clutch forming part of a cam assembly of the first embodiment of lock shown in Figs. ito 6; and Fig. 17 is a longitudinal sectional view similar to Fig. i6 but of a clutch forming part of a cam assembly of the second embodiment of lock shown in Figs. 7 and 8.

Cylinder locks in accordance with the invention may comprise either a single cylinder lock or a double cylinder lock but the two illustrated embodiments of lock, respectively labelled 1 and 2, are double cylinder locks and are key-operated on both sides. However, the second embodiment of lock 2, as shown in Figs 7 and 8, is asymmetrical, with an interior side and an exterior side (marked EXT in Fig. 7), and could be readily adapted for use with a turn such as a thumb turn knob on the interior side, as is described in more detail below. In contrast, the first embodiment of lock 1 shown in Figs. 1 to 6 is symmetrical and suitable for use either way round in a closure.

The illustrated embodiments will now be described in detail with identical components or components with identical functions in both embodiments given the same reference number.

The cylinder locks 1, 2 of both illustrated embodiments comprise an outer casing 3 adapted to extend through a closure such as a door. In the second embodiment of lock 2 the casing 3 has specific exterior and interior portions 4 and 5 respectively. These portions are connected by an integral central joining portion 6 and by a cam assembly 7. In the first embodiment of lock 1 the casing 3 also has two portions 4 and 5, an integral joining portion 6 and a cam assembly 7 but either of the two portions may comprise the exterior portion 4 or the interior portion 5 so that it does not matter which way round the lock 1 is fitted through the closure. However, for the purposes of this description it will be assumed that the portion labelled with reference 4 is located on the exterior side of the closure and the portion labelled with reference is located on the interior side of the closure. In both embodiments of lock 1, 2 the cam assembly 7 is adapted to operate an adjacent latching mechanism for the closure.

The central portion 6 of the casing in the second embodiment of lock 2 is provided with a groove 8 located adjacent the exterior portion 4. In the first embodiment of lock 1 the central portion 6 of the casing is provided with two grooves 8 that are respectively located adjacent each portion 4 and 5.

The groove or grooves 8 deliberately weaken the casing 3 so that if the lock is interfered with from the exterior side, typically by an attempt to deform the casing 3 to enable parts of the lock 1, 2 to be removed so that the latching mechanism can be exposed, the casing will break at the location of the groove 8 leaving the cam assembly 7 and interior portion 5 of the lock intact.

This makes it harder to interfere with the lock 1, 2 to gain access to a latching mechanism (not shown) of the closure.

The exterior and interior portions 4, of the casing 3 each comprise an independent key-operated locking mechanism with a cylindrical core 9 that is rotatably mounted within a cylindrical bore defined by the respective portion 4, of the casing 3. The two cores 9 of each lock 1, 2 each define a keyway 10 with a keyhole 11 at their outer ends. Their inner ends are connected to the cam assembly 7 that is located centrally of the casing 3. In the illustrated embodiments, all of the locking mechanisms are conventional pin tumbler mechanisms but other forms of locking mechanisms could be used.

The cam assembly 7 comprises a rotatably mounted cam 12 with a projecting lever 13 that is adapted to bear against a spring-loaded lever or similar (not shown) of the latching mechanism to open it. In order to enable the closure to be opened from both sides, the cam 12 is selectively connectable to the exterior and interior locking mechanisms on both sides of the casing 3 by a clutch 14 that is axially slidable through a U-shaped opening 15 in the cam 12 between the cylindrical cores 9.

In the present invention the clutch 14 comprises a bar with radially projecting flanges i6 at each end that each also has a pair of radial projections in the form of wings 17. The central portion of the bar has a generally cylindrical profile but with a flat i8 that extends between two of the wings 17 at opposite ends of the clutch 14, as shown in Fig. 15. The central portion of the clutch 14 fits within the U-shaped opening 15 of the cam 12 and the flat i8 ensures that when the clutch 14 rotates in either direction, the cam 12 is engaged and also rotates along with the clutch 14. Axial sliding of the clutch 14 through the opening 15 between the cylindrical cores 9, however, does not move the cam 12 and the flanges 16 form stops that prevent 14 the clutch from sliding out of the opening i completely at the ends of its travel. In addition, the clutch 14 is retained within the opening 15 by at least one circlip 19. In the first embodiment of lock 1, a pair of circlips 19 are present that locate in recesses 20 in the cam 12 on either side of the opening 15 as shown in Fig. 12. In the second embodiment of lock 2, a single circlip 19 is provided that locates in a recess 20 on the interior side of the cam 12 only as shown in Fig. 14.

The ends of the cores 9 adjacent the cam assembly 7 are hollow and define opposing open-ended, axially-extending slots 21. In addition, each comprises an internal annular groove 22 located at the base of the slots 21 and an external annular groove 23 adjacent the open ends of the slots 21 in which is located a clip 24 (see Figs. 3 and 8). The clutch 14 locates in the hollow ends of the cores 9, the wings 17 at each end of the clutch 14 locating within the slots 21 (see Fig. ). The hollow ends of the cores 9 themselves locate within the cam 12 on either side of the U-shaped opening 15 respectively and each is retained in position by the clip 24 that snaps into place in an adjacent annular recess 25 within the cam 12 so that when the cam 12 is rotated by the clutch 14, it can turn relative to either of the cores 9.

The profile of the ends of the cores 9 is preferably tapered, as shown in Figs. 9 and 10 to ease placement into the cam 12.

The clutch 14 is axially slidable within each of the cores 9 between a first position wherein the wings 17 are not aligned with the internal groove 22 of the core 9 and a second position wherein the wings 17 align with the internal groove 22 of the core 9. It will be appreciated that that when the clutch 14 is in the first position relative to one of the cores 9 it is also in the second position relative to the other core and vice versa. This is shown in Figs. 3 and 8 wherein the clutch 14 is shown in the first position relative to the cores 9 in the exterior portions 4 of the casings 3 and in the second position relative to the cores 9 in the interior portions 5 of the casings 3. The clutch 14 is moved into the second position relative to any core 9 by the insertion of a key into the keyway 10 of the other core g of the lock. When the key is fully inserted, the tip of its blade extends into the hollow end of the core 9 and makes contact with the end of the clutch 14 moving it axially along the casing 3 towards the opposite core 9 until the wings 17 at the opposite end of the clutch 14 align with the internal groove 22 of the other core 9. Similarly, a key fully inserted in the keyway 10 of the other core 9 moves the clutch 14 in the opposite direction. The clutch 14 is preferably spring-loaded so that when no key is inserted in either keyway 10, the clutch 14 locates in a predetermined position.

In the first embodiment of lock 1 shown in Figs. 1 to 6, the clutch 14 is spring-loaded such that when there is no key inserted in either keyway 10 it locates in a neutral position between the two cores 9 in neither the first nor the second position relative to either core 9. In the second embodiment of lock 2 shown in Figs. 7 and 8, the clutch 14 is spring loaded such that it locates in a position wherein it is in the first position relative to the core 9 in the exterior portion 4 of the casing 3 and in the second position relative to the core 9 in the interior portion of the casing 3. This means it remains unmoved when a key is inserted into the keyway 10 of the core 9 in the interior portion of the casing 3.

The clutch 14 in the first embodiment of lock 1 is spring-loaded on both sides. The bar of this clutch defines two recesses 26 at opposite sides thereof in each of which is located a compression spring 27 that acts between the bottom of its recess 26 and a ball-bearing 28 that bears against a surface 29 at the base of the hollow end of the adjacent core 9 (see Fig. io). The ball-bearings 28 could be replaced by bars or pins 30, as in the second embodiment of lock 2 (see Fig. 8), which only has a single recess 26 on the interior side of the clutch 14 as shown in Fig 17. It will be appreciated that, the compression springs 27 being of equal strength, when the lock 1 is locked the spring-loadings ensure that the clutch 14 adopts a neutral position that is equally spaced from the cores 9 and with the wings 17 at both ends of the clutch 14 unaligned with the grooves 22 in both cores 9.

In use, if a key is inserted into the keyway 10 of the core 9 in the exterior portion 4 of the casing 3 of the lock 1, then the clutch 14 is moved towards the core 9 in the internal portion 5 of the casing as shown in Figs. 3 and 8. This means that the wings 17 of the clutch 14 adjacent the internal portion 5 of the casing 3 align with the internal groove 22 of the core 9 within the internal portion 5 of the casing 3 but the wings 17 of the clutch 14 adjacent the external portion 4 of the casing 3 are located within the slots 21 of the core g of the external portion 4 unaligned with its groove 22, as shown in Fig. 5. Assuming the key is capable of opening the lock, then when the key is turned the core 9 is also turned relative to the casing 3 and the wings 17 are engaged by the core 9 so that the clutch 14 is also rotated. Rotation of the clutch 14 also forces the cam 12 to rotate and its lever 13 is brought to bear against the appropriate part of the latch mechanism to open it. However, on the interior side of the lock 1, 2 the wings 17 at the interior side of the clutch 14 are aligned with the internal groove 22 of the core 9 in the interior portion j of the casing 3. This means that when the clutch 14 rotates, the core 9 in the interior portion of the casing 3 does not rotate because the wings 17 on the interior side of the clutch 14 rotate relative to it within the groove 22.

When the key is withdrawn from the keyway 10, the spring-loading returns the clutch 14 back to its initial neutral position. It will be appreciated that if a key is inserted into the lock 1 from the internal side of the closure, then the lock 1 will operate in a similar way except that the core 9 within the internal side of the lock 1 will rotate leaving the core 9 within the external side of the lock 1 unmoved.

-10 -In contrast, in the second embodiment of lock 2, the spring-loading always ensures that the wings 17 on the external side of the clutch 14 align with the groove 22 in the core 9 in the external portion 4 of the lock 2 when there is no key located in either core 9. This means that the locking mechanism of the core 9 in the internal portion 5 of the casing 3 could be dispensed with and this core 9 adapted to form part of a simple thumb turn knob arrangement or similar. Only when a key is inserted into the keyway 10 in the core 9 in the external portion 4 of the casing 3 is the clutch 14 moved against the spring-loading into the position shown in Fig. 8 to enable the lock 2 to be opened from the exterior of the closure.

If either of the locks 1, 2 is unlawfully tampered with in an attempt to break the lock, it will be from the external side of the closure. Typically, criminals will attempt to break the casing 3 so that the core 9 in the external portion 4 of the lock 1, 2 can be gripped by a wrench and pulled out of the lock 1, 2 to expose the cam mechanism 7. In the present invention, if the core 9 in the external portion 4 of the lock 1, 2 is removed, the clutch 14 remains in place because the flanges 16 prevent it from passing through the U-shaped opening i in the cam 12. Similarly the circlip or circlips 19, particular that on the interior side of the cam 12 which cannot be accessed from the exterior side of the lock prevent the clutch 14 from being knocked sideways out of the opening 15. In addition, in the first embodiment of lock 1 if the core 9 in the exterior portion 4 of the lock 1 is removed the ball-bearing 28 and compression spring 27 on the exterior side of the lock 1 fall away leaving the clutch 14 in place. This enables the spring-loading on the interior side of the lock 1 to force the clutch 14 into its first position relative to the core 9 in the interior portion of the lock 1, namely with the wings 17 unaligned with the groove 22 of the core 9. This means that the clutch 14 cannot be rotated to rotate the cam 12 to open the latching mechanism. In the second embodiment, the clutch 14 is always in its first position relative to the core 9 in the interior portion of the lock 2 in any event. Hence, the solid bar of the clutch 14 prevents the tampering party from being able to access the latching mechanism or from moving the cam 12. In actuality, what -11 -happens as the core 9 on the exterior side of the lock 1, 2 is removed is that the spring-loading on the interior side of the clutch 14 moves the clutch 14 into its first position and then beyond it relative to the remaining core 9 as there is nothing now to stop it doing so until the flange 16 on the interior side of the clutch 14 contacts the circlip 19 on the interior side of the cam assembly 7. In this position the clutch 14 has moved sufficiently for the ball-bearing 28 or pin 30 to be forced out of its recess 26 so that it now sits between the clutch 14 and the adjacent interior core 9. If the tampering party now attempts to push the clutch 14 back towards the core 9 in the interior portion 5 of the lock 1, 2 the ball-bearing 28 or pin 30 acts as an obstruction preventing this from happening. The cam mechanism 7 is therefore fixed in position within the lock 1, 2 50 that the latching mechanism cannot be accessed or tripped into opening. Hence, the lock 1, 2 provides an improvement over existing cylinder locks as it obstructs access to the latching mechanism if the lock is broken into.

Claims

-12 -CLAIMS1. A cylinder lock for a closure comprising a casing; a first core rotatably mounted within the casing and forming a locking mechanism therewith; a cam rotatably mounted adjacent one end of the first core; and a clutch adapted to actuate rotation of the cam and being axially slidable relative to the first core between a first position wherein rotation of the first core relative to the casing engages the clutch and rotates the cam and a second position wherein there is no engagement between the first core and the clutch on rotation of the clutch; characterised in that the end of the first core adjacent the cam is hollow and comprises an internal groove, and in that the clutch locates in the hollow end of the first core and comprises a projection such that in said first position the projection is engaged by the first core and the clutch is rotated when the first core is rotated and in said second position the projection aligns with the groove such that on rotation of the first core the first core rotates relative to the clutch.
2. A lock as claimed in Claim 1, characterised in that the hollow end of the first core defines a slot into which the projection locates when the clutch is in said first position whereby the clutch is rotated when the first core is rotated.
3. A lock as claimed in Claim 1 or Claim 2, characterised in that the clutch is spring-loaded.
4. A lock as claimed in any of Claims 1 to 3, characterised in that a second core is rotatably mounted within the casing and the clutch comprises a bar which has at least one projection at each end thereof -13 -that locate respectively into slots defined by the first and second cores and which is axially slidable relative to the first and second cores such that when the clutch is in the first position relative to one of the cores it is also in the second position relative to the other core and vice versa.
5. A lock as claimed in Claim 4 when dependent on Claim 3, characterised in that the clutch is spring-loaded such that when there is no key inserted in either of the cores, it locates in a neutral position between the first and second cores such that neither core is rotatable relative to the other.
6. A lock as claimed in Claim 5, characterised in that when the clutch is in the neutral position the projections at each end of the clutch locate within their respective slot defined by the first or the second core but out of alignment with the internal groove of the core.
7. A lock as claimed in Claim 4 when dependent on Claim 3, characterised in that the clutch is spring-loaded such that when there is no key inserted into the first core, it locates in said first position relative to said first core and in said second position relative to said second core.
8. A lock as claimed in Claim 7, characterised in that said first core is located in a portion of the casing intended to be located on an exterior side of the closure and the second core is located in a portion of the casing intended to be located on an interior side of the closure.
9. A lock as claimed in Claims 8, characterised in that the second core is adapted to form part of a turn arrangement or similar.
10. A lock as claimed in any of Claims 4 to 9 when dependent on Claim 3, characterised in that the clutch is adapted to be contacted by a tip of a -14 -blade of a key inserted into the first core and moved against the bias of the spring-loading on the opposite side of the core into its first position relative to the first core and into its second position relative to the second core.
ii. A lock as claimed in Claim 3 or any of Claims 4 to 10 when dependent on Claim 3, characterised in that the or each spring loading comprises a spring-loaded ball-bearing or pin that is located in a recess defined in the clutch and that bears against a surface of the first or second core adjacent thereto.
12. A lock as claimed in any of Claims 1 to 11, characterised in that the clutch comprises a bar with a pair of radial projections in the form of wings at each end thereof.
13. A lock as claimed in Claim 12, characterised in that the wings project radially from a radially projecting flanges formed at the ends of the bar.
14. A lock as claimed in Claim 13, characterised in that the bar is axially slidable through a slot defined by the cam and is retained in the slot by the radially projecting flanges at its ends and by at least one circlip that locates in a recess defined by the cam.
15. A lock as claimed in any of Claims 1 to 14, characterised in that the hollow end of at least the first core locates within the cam and is retained in position by a clip that permits the cam to rotate relative to the core or cores.
i6. A cylinder lock for a closure substantially as described herein with reference to Figs. 1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 15 and 16 or Figs. 7, 8, 9, 10, 13, 14 and 17 of the accompanying drawings.