The principle of the key operated lock has been established for centuries and the various types available such as the mortice or"Chubb"lock and the cylinder or "Yale"lock are very well known. In most mortice locks the locking bolt is extended by one or more turns of the key in the lock, and some cylinder locks have a locking mechanism which also is operated by turning the key at least one turn. However, no matter how secure the lock is once engaged, existing arrangements have the shortcoming that it is not possible for the key-holder to determine the state in which he left the lock. There are therefore many instances where the key-holder having left the property or other article to which the lock is fitted, cannot recall whether he remembered to lock it on leaving. This invention therefore provides an improved key and lock combination where the key carries an indication as to the state in which the lock was left when last operated by that key.

Accordingly, in one aspect, this invention provides an improved key and lock combination, wherein the key includes indicator means responsive to the locking and unlocking

movements of the key to indicate the respective state of the lock.

. The respective state of the lock could be either the actual state of the lock or the immediately previous change of state of the lock applied by the key.

Preferably, the indicator means comprises a moveable indicator member which moves between"locked"and "unlocked"indicating positions. Thus the indicator member may conveniently shuttle between"locked"and"unlocked" indicating positions.

Alternatively, said indicator means may comprise a switchable display means such as a low current electronic device capable of switching between one state to indicate the"locked"position and another state to indicate the "unlocked"position. For example the indicator means could comprise a liquid crystal or other device which may be switched on or off to provide a distinctive display.

Preferably, the indicator member is moved between the "locked"and"unlocked"indicating positions by means of electro-magnetic force.

Preferably, at least one of the indicator member and the lock mechanism include permanent magnet means for generating said electro-magnetic force for moving said indicator member on rotation of said key.

The indicator means may include two spaced magnets (or magnetised regions) which co-operate with respective associated magnets (or magnetised regions) associated with

said lock mechanism. Alternatively, there may be just one magnet on the indicator means and associated with the lock mechanism and co-operating with either one or two magnets on the other component.

Preferably, said magnets (or magnetised regions) co- operate in use such that rotation of the key in the lock to move the lock from its"unlocked"position to its"locked" position causes the indicator member to be moved linearly to said"locked"indicating position, and rotation of the key in the lock to move it from the locked state to the unlocked state causes the indicating member to be moved linearly to the"unlocked"indicating position.

Preferably the magnets (or magnetised regions) associated with said lock are disposed on a hollow support which surrounds the portion of the key in which the magnets (or magnetised regions) of the indicator member are located.

In one embodiment, the key comprises a shaft of non- ferromagnetic material in which is located said indicating member, with said indicating member including an indicating portion viewable through a window or the like on the key.

Preferably said hollow support member is rotatably mounted adjacent to the key receiving aperture of the lock, and the arrangement is such that, on turning the key through 360°, movement of said key relative to said elongate hollow support is limited to a lesser amount and preferably substantially 180°.

In one embodiment, the mounting arrangement comprises a member designed to rotate with the key when the correct key is passed into the lock and having a drive face for engaging a drive pin or the like on said hollow support, and further having a relieved portion whereby alternate turning of the key in the clockwise and counter-clockwise direction to"lock"and"unlock"the lock mean that the hollow support is shifted for only about half a revolution.

The invention also extends to a key for use in the key and lock combination as described above. Thus the key may comprise a key bit, a shaft and a head, with an indicator member slidably mounted within the shaft and operating a display member viewable via an aperture in the key head.

The invention also extends to a lock for use in the key and lock combination as described above, said lock having magnetic means associated with one or both sides of the lock for causing in use the indicator member in a key of the type described to shuttle between the"locked"and "unlocked"positions.

Furthermore, the invention extends to kits for converting existing locks to operate in accordance with the combination set out above. Accordingly, a kit may comprise one or more of a key as described above, or a conversion device for fitting an hollow support of the type described above to the lock.

Whilst the invention has been described above, it extends to any inventive combination of the features set out above or in the following description.

The invention may be performed in various ways, and an embodiment thereof, with various modifications, will now be described by way of example only, reference being made to the accompanying drawings in which:- Figure 1 is a schematic view of a key for a key/lock combination in accordance with a first embodiment of this invention; Figure 2 is a schematic view of an indicator member for use in the key of Figure 1; Figure 3 is a schematic view showing a door lock in accordance with this invention; Figure 4 is an end view on a barrel member forming part of the door lock mechanism of Figure 3, Figure 5 is a view on the other end of the barrel illustrated in Figure 4 ; Figure 6 is a side view of the barrel of Figures 4 and 5; Figure 7 is a side view of a sleeve in which the barrel of Figures 4 to 6 is rotatably received, in the arrangement of Figure 3 ; Figure 8 illustrates the co-operation, in the arrangement of Figure 3, between the barrel of Figures 4 to 6 and a drive disc connected to the locking mechanism ; Figure 9 is a perspective view of the drive disc ;

Figures 10 (a) to (e) are views similar to Figure 8, but showing the relative configurations of the barrel and the drive disc as the key is turned 360° counter-clockwise to unlock the lock; Figures 11 (a) to (e) are views similar to Figure 10 but showing the relative configurations of the barrel and the drive disc as the key is turned 360° clockwise to lock the lock; Figures 12 (a) and (b) show the relative configurations of the magnet associated with the lock mechanism and the magnets on the indicator member as the key is turned from a locked position to an unlocked position ; Figures 13 (a) and 13 (b) show the relative configuration of the magnet associated with the lock mechanism and the magnets on the indicator member as the key is turned from an unlocked position to a locked position; Figure 14 is a front view of a second embodiment of lock in accordance with this invention; Figure 15 shows the moving components of the embodiment of Figure 14 rotated clockwise through 90° ; Figure 16 is a section view through the barrel and the drive disc of the embodiment of Figure 15 ; Figure 17 shows the embodiment with the outer retaining sleeve ;

Figure 18 shows schematically a drive disc for association with a lock; Figure 19 is a schematic side view of a third embodiment of a lock in accordance with this invention; Figure 20 is a view on the underneath of the third embodiment illustrated in Figure 19, but on an enlarged scale; Figure 21 is an underneath view similar to Figure 20 but showing a key of this invention inserted into the rear keyhole of the lock; Figure 22 is a view similar to that of Figure 21 but showing the key rotated in the lock by about 90 degrees in the counter-clockwise sense; Figure 23 is a view similar to Figure 21 except showing the key rotated through about 90 degrees in the clockwise sense; Figure 24 is a plan view of a key for the lock of Figure 19, showing the indicator member in the unlocked position; Figure 25 is a view of the key similar to Figure 24 but showing the indicator member in the locked position; Figure 26 is a side view of the indicator member of the key; Figure 27 is a front view on the internal face of one of the discs on the bolt thrower of the third embodiment ; Figure 28 is a front view on the bolt thrower of the third embodiment, together with the (left hand) single

magnet moving mechanism, showing the magnet moving mechanism in its rest position and with the right hand dual magnetic moving mechanism omitted for clarity; Figure 29 is a front view of the bolt thrower of Figure 27 and the magnet moving mechanism, but showing the bolt thrower rotated counter clockwise and the magnet moving mechanism in its extended position with the single magnet near to the key shaft; Figure 30 is a top plan view on the bolt thrower of Figure 27; Figure 31 is an underneath plan view on the bolt thrower of Figure 27; Figure 32 is a left hand view on the bolt thrower and magnet moving mechanism assembly of Figure 28; Figure 33 is a right hand view on the bolt thrower and magnet moving mechanism assembly shown in Figure 28; Figure 34 is a top plan view of the bolt thrower and magnet moving mechanism assembly shown in Figure 28, showing all three magnets in their rest positions ; Figure 35 is a view similar to Figure 34 except showing the two right hand magnets in their extended position adjacent the keyhole; Figure 36 is a view similar to Figure 34 except showing the right hand magnet extended to adjacent the keyhole, and Figure 37 is a schematic view of a docking sheath arrangement for a mobile phone or other networked item of

equipment for detecting the state of a key and transmitting this to other keyholders, and for changing the state of a key in the sheath.

Referring initially to the first embodiment shown in Figures 1 to 13, this is designed for a key and lock combination where the key, instead of having a projecting "bit", instead has a cylindrical shaft at the end of which is milled a series of coded grooves which operate the lock.

Figure 1 shows a key 10 having a shaft 12 with the milled grooves 14, and having a head 16. The head and shaft are provided with a longitudinal bore which slidably receives the stem 18 of an indicator member 20 (see Figure 2). The indicator member has a head 22 with coloured status indicator panels 24. The indicator member 20 is slidably mounted within the key, and the head 22 thereof co-operates with a viewing port 26 through which the relevant status panel 24 may be viewed. The indicator member may shuttle back and forth between a"open" indicating position in which an"open"status panel is aligned with the port 26, and a"closed"position in which a"closed"status panel is aligned with the port 26. The interior of the key is provided with a suitably sized internal chamber to accommodate sliding movement of the head 22 with its indicator panels. The status panels may be identified by colour, symbols or wording such as"open"and "closed".

The key is also provided with air passages 28 to prevent build-up of pressure. The shaft of the key, at least, is made of non-ferromagnetic material.

At spaced locations on the stem 18 are provided two magnets 32,34 respectively, and the end of the key bore remote from the head 16 carries a ferro-magnetic retaining disc 17 which co-operates with the magnet 32 on the end of the stem 18 of the indicator member 22 when the two are close together, to prevent inadvertent movement. Likewise a retaining ring 30 of ferro-magnetic material is provided in the bore to co-operate with the magnet 34 on the stem 18 of the indicating member 20, when the two are in close proximity, to provide a magnetic retaining effect on the stem.

Referring now to Figures 3 to 9, the lock has associated therewith an eccentric barrel member 36 which is of generally cylindrical form but offset relative to the axis of rotation of the key, and is rotatably received within an outer cylindrical sleeve 38 secured to the outer part of the lock. As will be seen from Figures 4 to 6, the barrel has a longitudinal bore 40 designed to receive the shaft 12 of the key 10. At opposite ends of the barrel 36, and at diametrically opposed positions, are provided respective magnets 42, and 44. These are spaced axially by approximately the same axial spacing as that of the magnets 32,34 with which they co-operate, substantially in anti- phase.

As can be more clearly seen in Figures 8 and 9, the lock includes a drive disc 46 which rotates with the key as it is turned in the lock. The drive disc is relieved on one side to provide a drive ledge 48. When assembled, the barrel 36 is mounted with one end thereof facing the drive disc 46, and a drive pin 50 projects from the end of the barrel 36 to co-operate with the drive ledge 48.

This arrangement is designed so that, as shown in Figures 10 and 11, when a key is inserted into the lock and turned counter-clockwise through 360°, the drive disc rotates with the key but the drive ledge 48 only engages the drive pin 50 for the last 180° or so, so that the barrel 36 rotates through just 180°. Likewise, as shown in Figure 11, when the key is thereafter inserted into the lock and turned clockwise, the drive disc 46 rotates through 360° but again the drive ledge 48 only drives the barrel 36 once the key has been turned through about 180°.

This arrangement, combined with the diametric positioning of the magnets 42 and 44, and the eccentricity of the barrel 36 relative to the axis of rotation of the key 10, means that the magnets 42 and 44 move alternately relative to the axis of the key 10. In other words as, say, magnet 44 is brought closer to the rotational axis of the key 10, so magnet 42 is being moved away therefrom.

This toggle action of the magnets 42 and 44 relative to the axis of the key on rotation thereof is harnessed to effect movement of the indicator member. This toggle action

occurs during the phase of movement when the drive ledge 48 is rotating the barrel 36 (i. e. through substantially the last 180° of a complete revolution).

Therefore, as seen in Figures 12 (a) and 12 (b), 12 (a) shows the condition at the instant at which magnet 34 is brought into effective magnetic range with magnet 44 ; the polarity and relative spacing of the magnets is chosen such that, at this instant, the repulsion effect causes the indicator member to be shuttled to the right as shown in Figure 12, thereby to adopt the position shown in Figure 12 (b). When however the key is rotated in the opposite sense by 360°, during the latter 180° of the movement thereof, when the drive disc is rotating the barrel 36, magnet 34 will move out of the magnetic range of magnet 44 and magnet 42 will be brought into the magnetic range of magnet 32. Magnets 32 and 42 are arranged with opposite polarity so as to attract each other. As shown in Figure 13, this causes the indicator member 20 to be shuttled to the left.

Referring now to the second embodiment shown in Figures 14 to 18, this is intended for particular use for a conventional key 10 with a projecting key bit 62 of the type shown in Figure 18. In this embodiment, similar parts will be given similar reference numerals but prefixed by 1, and will not be described in detail again. In this embodiment the lock has a drive disc 146 associated therewith and shown in more detail in Figure 18. Here the

disc is shown as a double-sided member with drive ledges 148 to either side of the lock. The drive disc has short hollow cylindrical portion 160 with a slot through which the bit 162 of the key may protrude. Likewise the drive disc 148 has a suitably shaped keyhole aperture (not shown) to allow the key to be slid in and out thereof. In this arrangement the eccentric barrel 136 is of somewhat shorter axial length than that of the previous embodiment. but has an outer cylindrical surface which is offset eccentrically with respect to the axis of rotation of the key 110. The barrel 136 is retained in an outer sleeve 138 which fits over the barrel to locate it and also acts as a bearing.

The sleeve 138 is secured to the lock, adjacent the lock aperture. Two such barrels are fitted to the lock, one to either side of the door.

Instead of having a plain cylindrical bore, the barrel has a cylindrical bore with opposite channels 164 provided in it to receive the bit 162 of the key. The barrel needs to have two such channels provided in it because, as before, on rotation of the key through 360°, the barrel is caused to rotate through just 180° by the drive ledge 148.

Accordingly, the barrel 136 needs to have one channel which is presented when the lock is in the unlocked position and one which is presented when the lock is in the locked position. As previously, the key has a moveable indicator member (not shown) which shuttles back and forth between a "locked"indicating position and an"unlocked"indicating

position. The indicator member has two magnets as previously which co-operate with suitably oriented magnets 142 and 144 on the barrel 136, so as alternately to repel and attract the indicator member to shuttle it between its "locked"and"unlocked"positions. In this embodiment, each drive disc 146 has a ledge 148 which as in the previous embodiment co-operates with a pin 150 on the barrel to convert the usual 360° turn of the key in either the locking or unlocking direction into a 180° movement of the barrel 136.

Referring now to Figures 19 to 23, the lock 200 comprises a slideable bolt 201 shown in Figure 19 in an extended position. Also shown is a single lever 202 and a spring 203, both of which are of conventional construction.

The lock illustrated will be of generally conventional construction with regard to the interaction of the key bit, the levers (typically five) and the bolt. At the centre of the lock there is a keyhole 204 to receive a key of the type having a laterally extending bit (and to be described in more detail in relation to Figures 24 to 26). The lock mechanism is contained within a generally rectangular box 205. Within the box 205, and coaxially supported with respect to the keyhole 204 is a bolt thrower 206. The bolt thrower co-operates with a left hand magnet 207 and two right hand magnets 208, the right hand magnets being connected to move together. The bolt thrower 206 is designed to receive and rotate with a key when turned in

the lock and its function is to move the magnet 207 alternately with the pair of magnets 208 in accordance with the angular position of the key in the lock. This is done by virtue of the fore and aft discs 209 and 210 respectively which have similarly profiled internally facing surfaces to provide a camming action to move a dual magnet support 213 (to the right of the keyhole as viewed in Figure 19) and a single magnet support 211 (on the left hand side of the keyhole in Figure 19), respectively. The dual magnet support 212 comprises a vertical member 212 to the top of which is connected a cross bar 223 carrying at opposite ends thereof the dual magnets 208 which run in respective guide channels 225. The vertical member 212 is connected at its foot to a slider arm 214 which passes over the floor of the box 206, under the keyhole 204 to terminate in an upstanding foot portion 215. The foot 215 bears against a compression spring 216 which has the effect of pushing the dual magnets 208 away from the axis of the keyhole to rest against a stop 217. The single magnet support 211 likewise comprises a vertical member 218 on the top of which is mounted the magnet 207 a cross bar 227 in the centre of which is carried said magnet 208 and at the ends of which are bearing blocks 229 which locate in respective guide channels. The lower end of the vertical support 218 is coupled to a slider arm 220 which extends over the floor of the lock box 206, beneath the keyhole 204

and has an upstanding foot 221 which engages a compression spring 222.

The upstanding feet 215 and 221 each have a camming surface 231,232 respectively which co-operates with a camming surface on the internal profiled surface of the respective disc 209,210 respectively of the bolt thrower 206. In the views of Figures 20 and 21, the respective camming surfaces are both shown in contact with a ledge on the respective disc of the bolt thrower. When the key is turned in a counter-clockwise sense as shown in Figure 22, a camming surface on the front disc 209 of the bolt thrower 206 engages the camming surface 232 on component 221 to draw the single magnet 207 next to the keyshaft.

On the other hand, as viewed in Figure 23, when rotated in the opposite direction, a camming surface on the rear disc 210 of the bolt thrower 206 engages the camming surface 231 on component 215 thereby pulling the dual magnet 208 adjacent the keyhole. In each instance when the single magnet 207 or the dual magnets 208 are being moved on one side of the lock the other magnet or magnets remain stationary as the relevant camming surface rides over the back of the ramp rather than operatively engaging the ledge on the bolt thrower.

Referring now to Figures 24 to 26, the exterior of the key 235 is generally conventional comprising a head 240, a shaft 241, a bit 242 for engaging the levers in the lock and a flange 243 to register the bit actually within the

lock. However the key is bored out and slideably receives in the bore 244 a hollow indicator sleeve 245. The ends of the bore are closed at the distal and proximal ends by respective a keeper magnet 246. Referring to Figure 26, the indicator sleeve is somewhat shorter than the remaining area of the bore and carries at its opposite ends respective magnets 247. The sleeve also includes spaced annular bearing ribs 249 to allow it to slide within the bore 244. The magnets 247 at opposite ends of the indicator sleeve 245 co-operate with the keeper magnets 245 and 246 in the key to allow the indicator sleeve to be toggled between the"unlocked"position shown in Figure 24 in which the indicator sleeve is in its right-most position relative to the bore and the"locked"position shown in Figure 25 in which the indicator sleeve is at its left-most position with respect to the bore. The head of the key has an aperture 250 through which the right-most end of the indicator sleeve 245 may be viewed. The right-most end of the indicator sleeve is colour coded with bands 251 and 252 respectively which identify to the user whether the key is in the locked or unlocked condition.

Referring now to Figures 27 to 36, as previously described, the bolt thrower 206 is of bobbin form comprising a central sleeve 260 with a slot 265 for the bit 242 of the key to slide in and a front disc 209 and a rear disc 210 respectively. The discs are carefully profiled to provide a uni-directional camming surface. In other words

the camming surface on the disc only provides operative movement of the associated engaging surface of the magnet moving mechanism when the angular movement of the disc is in the correct sense. Each disc comprises a first approximate thin sector region 261 of uniform thickness (say 1mm thick). Adjacent this and defining at the interface between the two a camming ledge 262, is a thicker surface 263, say of 2mm thick. Finally there is a ramp sector 264 which gradually diminishes in thickness with angular direction to provide a ramp extending angularly between the thick interface between the thicker surface 263 and the ramp sector 264, and the interface between the ramp sector and the thin sector 261. The disc is arranged such that the profiled face thereof faces internally towards the other disc, with the externally facing surface being plain (see e. g. Figures 30 and 31). The internal face of the rear disc has the same profile, but rotated 180° about the vertical axis, as can be seen again in Figures 30 and 31.

Because of this arrangement they have an opposite effect on the parts that connect to them.

Figure 28 shows the left hand magnet moving mechanism in its rest position; the right hand (dual) magnet moving mechanism has been removed for clarity. The rear disc 210 drives this mechanism. The abutment ledge 262 is shown just in engagement with the cam face 232 on the foot 221 of the magnet moving mechanism. Counter clockwise movement of the disc 210 (to the position shown in Figure 29) means

that the camming surface 262 urges the foot 221 to the right, against the bias of the spring 222 and thereby moving the single magnet 207 forward to lie adjacent the sleeve 260. Continued counter clockwise movement of the disc 210 will maintain the magnet 207 adjacent the sleeve 260 until the foot 221 eventually loses contact with the camming surface 262 somewhere along the slope or ramp portion 264. At that point the spring 222 will urge the magnet 207 back to its rest position. It is important to note that, should the disc 210 be rotated clockwise, the magnet moving mechanism will not be operatively influenced by the profile of the disc because it will simply ride up over the ramp due to the bevelled surface on the other side of the cam face 232 and so the magnet moving mechanism will simply be shifted slightly out of the plane of the paper but will not impart axial movement to it.

It will be appreciated that the other disc of the bolt thrower co-operates with the dual magnet moving mechanism and essentially moves the dual magnets in a similar manner when a key is rotated clockwise in the lock as viewed.

In other words, referring to Figures 34 to 36, when a key is inserted into the lock, when it is at zero degrees, i. e. the bit is facing directly downwardly, both the single magnet 207 and the dual magnets 208 are at their rest positions as far away from the sleeve 260 as possible.

Turning the key through 360° clockwise to unlock the lock will, in the first 90° of movement, bring the dual magnets

208 close to the shaft and then release them at about 180°.

The single central magnet will remain unmoved.

Turning the key counterclockwise through 360° will, for the first 90°, urge the single magnet 207 to lie adjacent the shaft (Figure 36) and then after about 180° rotation it will release the magnet 207.

The device can be"handed"for either direction of rotation. For example, assuming that lock has been left unlocked, and a key is introduced into the lock from the side marked with arrow A in Figure 34, and that, to lock the lock, the key needs to be turned counterclockwise. As previously described, this will have no effect on the dual magnets 208 but will cause the single magnet 207 to be advanced to the shaft and then relaxed as shown in Figures 28 and 29. Assuming that the key is with the indicator in the unlocked position as shown in Figure 24, this will mean that the single magnet 207 (which is close to the end of the key) attracts the magnet 247 in the end of the indicator sleeve thus pulling the indicator sleeve to the distal end of the key, thus moving the indicator member from the unlocked position shown in Figure 24 to the locked position shown in Figure 25.

Assuming then that the locked key at some later stage is introduced into the lock (note that this could be either side) and then rotated in a sense to unlock the lock, the dual magnets 208 will be advanced towards the sleeve 260 and then released. Irrespective of which side the key has

entered, on rotation of the key in the unlocking sense it will in effect be approached by one of the dual magnets only, as the other magnet will be facing a point beyond the end of the range of movement of the magnet. Thus in effect a magnet will temporarily be brought adjacent a point further up the key shaft from the point where the single magnet is applied. This action will attract the magnet 247 in the end of the indicator member causing the indicator to move away from the keeper magnet 245 and causing the keeper magnet 247 on the other end of the indicator member to become lightly magnetically bound to the keeper at the handle end of the key, and causing the indicator to display the unlocked condition through aperture 250.

Referring now to Figure 36, there is shown a mobile phone 400 with a key holster 402 attached. In this embodiment, a key of the type according to any of the previous arrangements may be inserted into the holster 401.

On detecting the presence of a key, a control circuit 402 allocates a time to this event. At the upper end of the holster is a photo-electric cell or the like which detects the state of the indicator member via the aperture 250 in the key head 240. If the control circuit 402 detects that the state of the key has changed then the appropriate information (time, state of the lock, keyholder) are sent via a communications network to other keyholders. The holster is also equipped with a magnetic coil arrangement 403 which is under the control of the circuit 402 to force

a change in the state of a key according to information received via the communications network.

It is important in such an arrangement that the time must be checked frequently to ensure accuracy. This could be done for example by checking the time signal from Greenwich. In this way, as soon as the latest key to use the lock is placed in the user's holster, the state of the key is detected and transmitted to all other keyholders on the network having the appropriate equipment, and the states of the keys are all synchronised. The holster could be attached to a networked computer or to a network accessed by security personnel.