AU2005201448B2 - A Privacy Adapter Containing a Clutch Mechanism - Google Patents

Abstract

Abstract A lock for a door has a privacy function, that enables the outside handle of the lock to be made inoperative. The particular privacy function as a clutch mechanism that can 5 be disengaged which means that the outside handle can still be turned but will not retract the latch tongue. The clutch mechanism can also be engaged to enable the outside handle to be active. The engagement and disengagement of the clutch mechanism is achieved by depressing a small button on the inside of the door. 10 11 27 26 12 1 28 14 2 3 1 29 3 1

Description

1 A Privacy Adapter Containing a Clutch Mechanism Field of the Invention 5 This invention is directed to a lock particularly for use on an internal door and which can function as a privacy adapter by which is meant that the door can be locked from the outside but can be operated from the inside. This type of lock finds particular suitability with bathroom doors, although it should be appreciated that no particular limitation is meant thereby. 10 Background Art A privacy adapter is a term used for a particular type of lock. The lock typically comprises an external handle and an internal handle. The external handle can be 15 "locked" by which is meant that the external handle cannot open the door. The mechanism of the lock is such that a person inside the bathroom can lock and unlock the external handle. In order to provide some level of "override" mechanism, it is known to provide 20 something that enables the external lock handle to be operated in an emergency (for instance if a person on the outside of the door needs to get in). Although there are many types of privacy adapters available in the marketplace, one disadvantage with many of these is that when the external handle is locked, it is 25 unable to rotate. A person on the outside can attempt to force the handle and this can cause damage to the internal components of the lock. In our earlier patent 737076 we described an electrically controlled lock that finds suitability in hotels etc and which contains a solenoid that can provide a privacy 30 function. However, this type of electrically controlled lock finds little suitability in residential uses such as homes. Therefore, there would be an advantage if a privacy adapter could be provided that 2a does not contain any electrical components and which can overcome at least the disadvantage of the outside handle being locked against rotation when the outside of the door is locked. 5 It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country. Object of the Invention 10 It is an object of the invention to provide a lock, and particularly a lock of the type which is known as a privacy adapter and which can overcome at least some of the above-mentioned disadvantages or provide a useful or commercial choice. 15 In one form, the invention resides in a lock with a clutch mechanism, the clutch mechanism having a drive plate and a driven plate, the drive plate being associated with an outside handle such that, in use, rotation of the outside handle causes rotation of the drive plate, the driven plate being associated with an inside handle such that, in 20 use, rotation of the inside handle causes rotation of the driven plate, the lock also comprising a latch spindle and a latch tongue, the latch spindle being associated with the driven plate such that rotation of the latch spindle is caused upon rotation of the driven plate and rotation of the latch spindle causes retraction of the latch tongue, 25 the clutch mechanism having an engaged condition in which the drive plate is in contact with the driven plate such that rotation of the drive plate causes rotation of the driven plate, and a disengaged condition in which the drive plate and driven plate are separated such that rotation of the drive plate does not cause rotation of the driven plate, 30 the lock further comprising a manually operable button which, in use, is on the inside of the lock, and an actuator which is operatively associated with the button such that operation of the button moves the actuator from a second position to a first position, the actuator comprising a cam which inserts between, and separates, 2b the drive plate and the driven plate when the actuator is in the first position, but which does not prevent contact between the plates when the actuator is in the second position, the actuator further including a portion which, in use, can be accessed 5 from the outside of the lock to move the actuator from the first position to the second position. Thus, the lock now allows the "outside" handle to be turned even when the lock is in the locked position. Consequently, a person on the outside of the door is not 10 presented with a "non rotating" handle that can be forced and damage the internal components of the lock. Instead, a person on the outside of the door can still rotate the handle, but because the clutch is disengaged, rotation of the outside handle does not operate the latch tongue and therefore does not open the door.

3 A person on the inside can push (or otherwise manipulate) the button to engage or disengage the clutch mechanism in the lock and therefore to enable the outside handle to open the door, or to rotate without opening the door. S It is preferred to have an emergency override mechanism such that a person on the outside of the door can override the lock mechanism to open the door should it be necessary to do so. In one form, the emergency override mechanism may comprise an opening in part of the lock componentry that is on the outside of the door and which can allow an instrument such as a knife, pen, ruler etc to be pushed through the hole to 10 unlock the lock, for instance by causing the clutch to engage. The lock can be used in any particular situation where a lock having this type of privacy mechanism will find suitability. It is not considered that the invention should be limited only to the use of the lock on bathroom doors and the lock may be 15 applicable in other circumstances. It is considered that the main use of this type of lock will be in relation to doors although there may be circumstances where the lock may be used on windows. The lock will typically be used on hinged doors although it is considered that the lock may also be used on sliding doors and the like. 20 The lock will typically ultimately contain an external handle and an internal handle. For ease of convenience, the external handle will be considered as the one on the outside of the door and the internal handle will be considered as the one on the inside of the door. Also, for case of convenience, the term "outside" of the lock may include the part of the lock that is accessible or is on the outside of the door and the term 25 "inside" of the lock may include the part of the lock that is accessible or is on the inside of the door. The handle may comprise any suitable type of handle and will typically comprise a lever handle or a knob. However, it is not considered that the invention should be 30 limited to any particular shape, size, manufacture and the like of the handle. The lock will typically comprise a spindle that can rotate about its longitudinal axis. The spindle will typically be attached to a latch tongue assembly which can be quite 4 conventional. Thus, rotation of the spindle will cause retraction of the latch tongue. Conversely, if the spindle is held against rotation, the latch tongue will not retract. The lock will typically comprise a first component that is screwed (or otherwise 5 attached) to the outside of the door, and a second component that is screwed (or otherwise attached) to the inside of the door. The door will typically contain a through bore to enable a spindle to connect to the first component and the second component, and a further opening will typically be cut into the edge of the door to accommodate the latch tongue, this also being quite conventional. 10 The first component and the second component will typically comprise a mounting plate that can be attached to the door (typically by screws), and a housing that can be attached to the mounting plate, the housing containing various components of the lock (for instance the clutch mechanism etc). 15 The clutch mechanism may be provided within the first component and therefore may be provided on the outside of the door. The clutch mechanism will typically comprise a first clutch plate and a second clutch plate which, for the sake of convenience, can be called a drive plate and a driven plate. 20 The clutch mechanism may comprise additional plates. In order to enable the clutch plates to firmly grip each other when the clutch is engaged, it is preferred that at least one clutch plate, and preferably both clutch plates 25 are profiled to enhance the grip. For instance, one clutch plate may be provided with at least one projection and the other clutch plate may be provided with at least one recess such that the projection can at least partially enter into the recess when the clutch is engaged to provide a firmer locking arrangement. Suitably, one clutch plate will be provided with a plurality of projections and the other clutch plate will be 30 provided with a plurality of corresponding recesses. The projections may comprise buttons, ribs, ridges, projections having other shapes and configurations and the like. Similarly, the recesses may have corresponding shapes. It is envisaged that each clutch plate may comprise projections and recesses.

It is preferred that the projections are sized and configured such that if the clutch plates are separated by a few millimetres, this will be sufficient to disengage the clutch mechanism. 5 Each clutch plate may be substantially planar if desired and may be substantially circular although it is envisaged that the clutch plates may be oval, rectangular, or have other shapes, or be non-planar, providing that the clutch plates can still engage and disengage. 10 It is envisaged that the clutch plates will directly contact each other when engaged although it may be considered desirable to have some form of intermediate member that enables one clutch plate to be operatively engaged or operatively disengaged with the other clutch plate. 15 Biasing means may be provided to bias at least one clutch plate to the other clutch plate such that the clutch mechanism naturally adopts the engaged position. The biasing means may comprise a spring. The spring may bias the drive plate to the driven plate. 20 Suitably, the clutch mechanism contains means to enable the mechanism to rotate the spindle. Typically, the driven plate will contain some form of attachment means or engagement means that can attach to one end of the spindle such that rotation of the driven plate will cause rotation of the spindle. However, no particular limitation 25 should be placed on the invention merely by illustrating this preferred method of engaging the clutch mechanism with the spindle. Suitably, the drive plate is operatively associated with an external handle such that rotation of the external handle rotates the drive plate. 30 6 Thus, rotation of the external handle can rotate the drive plate, but if the clutch is disengaged, rotation of the drive plate will not cause rotation of the driven plate and therefore will not cause rotation of the spindle and therefore will not cause retraction of the latch tongue. 5 The lock contains an actuator, The actuator can function to operate the clutch mechanism, for instance to cause the clutch mechanism to engage or disengage. The actuator is preferably within, or substantially within the confines of the lock, and 10 will typically be positioned within the first component which may be on the outside of the door. The actuator can move in any suitable manner to directly or indirectly cause the clutch mechanism to engage or disengage. In a preferred form, the actuator can slide between a clutch engaging position and a clutch disengaging position. 15 The actuator may comprise a separate member that is fitted to the lock. The separate member may comprise a cam. Movement of the actuator to a first position may cause the cam to force at least one of the drive plates out of engagement with the other drive plate. Typically, the cam will force the drive plate out of engagement with the driven plate. Movement of the actuator to a second (retracted) position can allow the drive 20 plate to engage each other. Suitably, the actuator also comprises part of an emergency override mechanism which enables at least part of the actuator to be directly or indirectly contacted by an item (for instance a knife, pen, ruler) to push or otherwise move the actuator back to the 25 second retracted position to enable the outside handle to open the door. This will be described in greater detail below. The lock will typically comprise a second component. The second component will typically be attached to the inside of the door. The second component will typically 30 be attached to an internal handle which is operatively associated with the common spindle such that rotation of the internal handle causes rotation of the spindle and therefore retraction of the latch tongue.

7 The second component may contain the button that can be operated manually by a person on the inside of the door to "lock" or "unlock" the external handle. It should be appreciated that the term "button" should be given a broad meaning and 5 may comprise any type of projection or part that can be pressed or otherwise contacted by a person. The button can be pushed, twisted, rotated, pulled and the like to lock or unlock the external handle. If desired, a number of such buttons may be provided. The button may comprise a projection, a snib, a ring, or any other type of suitable structure that enables the button to be operated. It is preferred however that the button 10 comprises a member that can be pushed downwardly, or into, the lock. The button is typically operatively associated ultimately with the clutch mechanism such that operation of the button will disengage the clutch mechanism. In a preferred embodiment, depression of the button will cause the clutch mechanism to be 15 disengaged which results in the external handle being "locked" by which is meant that the external handle can be rotated but the rotation will not cause retraction of the latch tongue. As it is preferred that the clutch mechanism and the actuator is in the first component, 20 and that the button is in the second component, some form of link member or members may be required to enable the button to be operatively associated with the actuator that engages or disengages the clutch mechanism. In one form, the link member comprises a small spindle that is operated upon 25 operation of the button. The spindle may operate by being rotated at least partially about the longitudinal axis. However, the spindle may also slide if desired. The spindle may be operatively associated either directly or indirectly with the actuator. It is preferred that the spindle engages with a secondary actuator and that the 30 secondary actuator operates the actuator that engages with the clutch mechanism. Of course, no particular limitation should be placed on the invention merely by the particularisation of these preferred features.

8 Brief Description of the Drawings An embodiment of the invention will be described with reference to the following drawings in which: 5 Figure 1. Illustrates part of the lock that is positioned on the outside of the door and can comprise the first component. Figure 2. Illustrates part of the lock that is positioned on the inside of the door 10 and can comprise the second component. Figure 3. Illustrates an end view and a section view of the first component. Figure 4. Illustrates an end view and a section view of the second component. 15 Best Mode Referring initially to figure 1, this illustrates the first component of the lock which is the part of the lock that can be fixed to the outside of the door. The main components 20 illustrated in figure 1 are as follows -- a spring 10 which is fitted inside an external handle (not illustrated), a mounting plate 11, a drive plate 12 which forms part of the clutch mechanism, a housing 13 that holds the clutch components together, a driven plate 14 which forms part of the clutch mechanism, a spindle 15, an actuator 16 that functions to engage or disengage the clutch plate and which will be described in 25 greater detail below, a secondary actuator 17 that forms part of a link mechanism to link the button which is on the inside of the door ultimately with the actuator 16 and which will be described in greater detail below, and a housing 18 into which the various components can be fitted. 30 Figure 3 illustrates an end view and a section view of these components. Referring now to figure 2, this illustrates the second component of the lock which is the part of the lock that can be fixed to the inside of the door. The main components 9 are a mounting plate 20, a button 21, a link member in the form of a small spindle 22, and a housing 23 to house these components. The spindle 15 illustrated in figure 1 and in figure 3 extends through the door and 5 interconnects the first component of the lock on the outside of the door (figure 1) with the second component of the lock on the inside of the door (figure 2). Referring in greater detail to the components in figure 1, mounting plate 11 comprises a circular metal member that can be screwed to the door. A door rose (not illustrated) 10 can then be mounted to the front of the mounting plate 11, and the door rose can support an external handle (also not illustrated). The door rose can be conventional in design. The external handle (not illustrated) will conventionally contain an inner end that 15 passes through the central opening in mounting plate II and which is fixed to a square boss 26 extending from drive plate 12. Typically, the inner end of the handle will contain a recess which is configured to fit over the boss 26. This is quite conventional. The recess in the handle can also accommodate spring 10. Boss 26 contains a small central recess 27 to accommodate one end of spring 10. Thus, spring 20 10 is trapped between boss 26 and the external handle and functions to bias the drive plate 12 into engagement with the driven plate 14. Drive plate 12 comprises a circular disk that engages with driven plate 14 when the two plates are together. To assist with the attachment of the two plates together, the 25 driven plate 14 contains some recesses 28, and the facing side of the drive plate (not illustrated in figure 1 that only illustrates the rear side of the drive plate) contains similar type projections that pass into recesses 28. Thus, if drive plate 12 engages against driven plate 14, the two plates will rotate together. 30 As drive plate 12 is attached to the external handle (external handle not illustrated), rotation of the external handle will always cause rotation of drive plate 12. That is, in the particular embodiment, drive plate 12 will always rotate upon rotation of the external handle.

10 The housing 13 extends substantially about drive plate 12 and driven plate 14, and the housing together with the drive plates comprises the clutch mechanism. 5 The driven plate 14 is attached to spindle 15. Spindle 15 is a typical "square bar" type spindle. In the middle of the spindle is a small recess 29 that engages to the latch tongue mechanism which is also not illustrated but which is quite conventional in design. The latch tongue mechanism is a separate component that contains a rear square hole and the spindle slides into the square hole. The square configuration 10 ensures that rotation of the spindle causes retraction of the latch tongue. The latch tongue mechanism typically contains a spring which means that if the handle is released, the spring will automatically push the latch tongue back into the extended locking position. This is quite conventional. 15 The end of spindle 15 passes into an opening in driven plate 14 as illustrated in figure 1, and a small circlip 30 is used to attach the spindle 15 to the driven plate 14. The attachment is such that if the driven plate 14 is rotated, spindle 15 will also be rotated. Thus, if the clutch mechanism is in the engaged position where drive plate 12 engages 20 against driven plate 14, it can be seen that operation of the external handle will cause rotation of spindle 15 and therefore retraction of the latch tongue. Therefore, the external handle is now in the "operable" condition and can lock and unlock the door. The clutch mechanism can be disengaged by forcing back the drive plate 12 against 25 engagement to driven plate 14. In the preferred embodiment, this is achieved by actuator 16. Actuator 16 has a large central opening through which the spindle can pass such that the spindle can rotate without striking any part of the actuator. The actuator contains two end portions 31, 32. End portion 32 contains a cam 33. 30 The actuator 16 is positioned within the housing 18 of the first component for sliding movement along an axis which is at right angles to the longitudinal axis of the spindle. Put differently, actuator 16 can reciprocate or slide transversely to the 11 rotation axis of the spindle 15. The degree of sliding movement will typically be between 2-5 mm and in the particular embodiment will be about 2.5 mm which is not large but is sufficient to enable the actuator to disengage the clutch mechanism. 5 In use, actuator 16 is positioned behind driven plate 14. Cam 33 on actuator 16 projects somewhat forwardly which means that when the actuator is positioned behind driven plate 14, the cam is positioned between the driven plate 14 and the drive plate 12. At this stage, it should be appreciated that drive plate 12 is biased by spring 10 and can be pushed backwardly, but driven plate 14 is attached to the frontal spindle 15 10 and is unable to be pushed backwardly. The actuator 16 can be pushed transversely which means that cam 33 now pushes between the plates of the clutch mechanism and forces drive plate 12 back against the bias of spring 10. Once this occurs, drive plate 12 no longer engages with driven plate 15 14. Consequently, the external handle, when rotated, will cause rotation of drive plate 12 but will no longer cause rotation of driven plate 14. The external handle is now "dead" or "locked" which does not mean that the external handle cannot rotate but means that rotation of the external handle does not cause rotation of spindle 15 and therefore does not cause retraction of the latch tongue. 20 The actuator 16 can be manipulated between the clutch disengaging position and the clutch engaging position ultimately by the button 21 on the second component and this will be described in greater detail below. However, actuator 16 also forms part of an emergency override mechanism that enables the external handle to be operated to 25 open the door. In the particular embodiment, this is achieved using the end portion 31 of the actuator. The end portion 31 sits just within the periphery of an opening 34 in housing 18 (see figure 1). Thus, when the first component is fitted to the door, there will be an opening 34 but the end portion 31 will sit discreetly just within the confines of the first component. In an emergency, a knife, pen, ruler etc can be pushed into 30 opening 34, and this will push actuator 16 into the "retracted" position where cam 33 is no longer pushing back drive plate 12 and therefore where drive plate 12 is now biased by spring 10 into engagement with driven plate 14.

12 Referring now to the features of the "inside" part of the lock, that is the second component illustrated in figure 2, this illustrates a mounting plate 20 and a housing 23. With this component, the housing 23 sits between the mounting plate 20 and the inside of the door. That is, housing 23 is sandwiched between the mounting plate 20 5 and the door. An internal handle is attached to the common spindle 15 which passes through the central opening in housing 23 and mounting plate 20 . A rose (not illustrated) will typically be attached over the top of housing 23 to hide the internal components, this being quite conventional. 10 The arrangement is such that rotation of the internal handle always causes rotation of spindle 15 and always causes rotation of driven plate 14. Thus, rotation of the internal lever handle always causes retraction of the latch tongue and therefore opening of the door. 15 A person on the inside of the door can "lock" the external handle on the outside of the door by depressing button 21. Button 21 is a small sliding member that sits within a cavity 36 on the inside of housing 23. The button 21 can move between a projecting position (illustrated in figure 4) and a depressed position (not illustrated). 20 The button 22 contains an opening 37 of a particular shape. The opening 37 captures the head portion 38 of a small spindle 22. The arrangement is such that when the button is depressed, it will cause part rotation of the small spindle 22 about the longitudinal axis of the spindle. Conversely, when the button is returned to the extended position, the small spindle 22 will be rotated in an opposite direction. The 25 small spindle 22 passes through an opening in housing 23 and engages with the small secondary adapter 17 which forms part of the first component of the lock and which is illustrated in figure 1. The attachment of these parts is such that rotation of the small spindle 22 will also cause rotation of the secondary adapter 17. 30 Referring now to figure 1, the secondary adapter 17 contains a cam 40 that engages into the rear of actuator 16. Thus, rotation of the secondary adapter will cause rotation of cam 40 which will push actuator 16 into engagement with drive plate 12 to disengage the clutch.

13 As the secondary adapter 17 is connected to the small spindle 22 which is connected to button 21, the arrangement is such that depression of button 21 will cause rotation of small spindle 22, and therefore rotation of the secondary adapter 17 and therefore 5 operation of actuator 16. Thus, a person on the inside of the door can depress button 21 to cause the outside handle of the door to be disengaged and inoperative. This ensures a privacy mode. To "release" button 21, all that is necessary is to turn the inside handle. When the 10 inside handle is turned, button 21 will automatically return to the extended position which, ultimately, will cause the clutch to return to the engaged position to enable the outside handle to be operated. How this operates is as follows: rotation of the inside handle causes rotation of spindle 15 and rotation of driven plate 14. Referring now to figure 1, driven plate 14 is not entirely circular and has a cam profile about its 15 perimeter. Thus, as the driven plate 14 rotate, it will "kick" the cam 33 of actuator 16 into the release position to reengage drive plate 12 to driven plate 14. As the actuator 16 moves to the "release" position, this movement will cause counter rotation of the secondary adapter 17 as the cam 40 of the secondary adapter 17 is trapped within actuator 16. Then, counter rotation of adapter 17 will cause counter rotation of the 20 small spindle 22 which will force button 21 back into the "up" position. Thus, the lock according to the present invention provides a privacy function in a relatively simple manner. The privacy function manifests itself by making the external handle "dead" while still enabling the external handle to be turned (but not 25 operating the latch tongue). The privacy function can be operated very conveniently by depressing the small button on the inside of the lock. Turning of the inside handle (to leave the bathroom etc) causes the button to be returned to the "up" position without needing to manipulate the button directly. 30 Throughout the specification and the claims (if present), unless the context requires otherwise, the term "comprise", or variations such as "comprises" or "comprising", will be understood to apply the inclusion of the stated integer or group of integers but not the exclusion of any other integer or group of integers.

14 Throughout the specification and claims (if present), unless the context requires otherwise, the term "substantially" or "about" will be understood to not be limited to the value for the range qualified by the terms. 5 It should be appreciated that various other changes and modifications can be made to any embodiment described without departing from the spirit and scope of the invention.

Claims (16)

1. A lock with a clutch mechanism, the clutch mechanism having a drive plate and a driven plate, 5 the drive plate being associated with an outside handle such that, in use, rotation of the outside handle causes rotation of the drive plate, the driven plate being associated with an inside handle such that, in use, rotation of the inside handle causes rotation of the driven plate, the lock also comprising a latch spindle and a latch tongue, the latch 10 spindle being associated with the driven plate such that rotation of the latch spindle is caused upon rotation of the driven plate and rotation of the latch spindle causes retraction of the latch tongue, the clutch mechanism having an engaged condition in which the drive plate is in contact with the driven plate such that rotation of the drive plate causes 15 rotation of the driven plate, and a disengaged condition in which the drive plate and driven plate are separated such that rotation of the drive plate does not cause rotation of the driven plate, the lock further comprising a manually operable button which, in use, is on the inside of the lock, and an actuator which is operatively associated with the 20 button such that operation of the button moves the actuator from a second position to a first position, the actuator comprising a cam which inserts between, and separates, the drive plate and the driven plate when the actuator is in the first position, but which does not prevent contact between the plates when the actuator is in the second position, 25 the actuator further including a portion which, in use, can be accessed from the outside of the lock to move the actuator from the first position to the second position.

2. The lock as claimed in claim 1, wherein the configuration of the lock 30 comprises a first component adapted for attachment to the outside of the door, and a second component adapted for attachment to the inside of the door.

3. The lock as claimed in claim 2, wherein the first component contains 16 the clutch mechanism and the actuator, and the second component contains the button.

4. The lock as claimed in claim 2 or claim 3, wherein the latch spindle interconnects the first component and the second component. 5

5. The lock as claimed in any one of the preceding claims, wherein rotation of the outside handle always causes rotation of the drive plate.

6. The lock as claimed in any one of the preceding claims, wherein 10 rotation of the inside handle always causes rotation of the driven plate.

7. The lock as claimed in any one of the preceding claims, wherein the drive plate is biased against the driven plate. 15

8. The lock as claimed in claim 7, wherein the drive plate is biased against the driven plate by a spring that, in use, is adapted to extend at least partially into the outside handle.

9. The lock as claimed in any one of the preceding claims, wherein the 20 latch spindle is connected to the driven plate and, in use, is attachable to the inside handle such that rotation of the inside handle causes rotation of the latch spindle and the driven plate.

10. The lock as claimed in any one of the preceding claims, wherein the 25 actuator is slidable between the first position and the second.

11. The lock as claimed in claim 2, or the lock as claimed in any one of claims 3 to 10 when dependent on claim 2, further comprising a button spindle which is at least partially positioned within the second component, the button spindle being 30 rotatable about its longitudinal axis upon operation of the button, the button spindle being operatively associated with the actuator such that operation of the button causes rotation of the button spindle and movement of the actuator from the second position to the first position. 17

12. The lock as claimed in claim 11, wherein the button spindle engages with a secondary adapter, which is positioned at least partially within the first component, the secondary adapter engaging with the actuator to move the actuator 5 from the second position to the first position.

13. The lock as claimed in any one of the preceding claims, comprising means to return the button to its initial position upon rotation of the inside handle. 10

14. The lock as claimed in claim 13, wherein the means comprises a cam surface on the driven plate such that, when the actuator is in the first position, rotation of the driven plate causes the cam surface on the driven plate to contact the cam of the actuator and return the actuator to the second position.

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

16. The lock as claimed in any one of the preceding claims, wherein the portion of the actuator which, in use, can be accessed from the outside of the lock is 20 accessible only by using a thin object, and the thin object can contact the said portion and move the actuator from the first position to the second position.