GB2393479A - Lock with different keys - Google Patents

Abstract

There is disclosed a lock which may be placed into two or more different configurations and which may be used with two or more respective different keys. When the lock is in a first configuration then a first key, but not a second key, may be used to operate the lock. When the lock is in a second configuration then the second key may be used to operate the lock. The configuration of the lock is selected using a knob which is moved between two or more positions. In one embodiment the lock is of the lever type, in another embodiment the lock is of the cylinder type.

Description

23934 79

LOCK WITH DIFFERENT KEYS

This invention relates to a lock which may be used with different keys, and more particularly but not 5 exclusively, to lever locks and cylinder locks that may be used with different keys.

A typical problem faced by many householders is that of allowing access to their house, whilst they are away 10 during the day, to tradesmen, for example plumbers, buildings or decorators. Typically, a householder will give a key to the tradesman so that the tradesman can enter the house whilst the householder is away. However, there is the risk that an unscrupulous tradesman might 15 make and keep an illicit copy of the key, with the result that the tradesman (or his associates) will be able to enter the house on a subsequent occasion without permission from the householder. There is therefore a need to improve the security arrangements for allowing 20 tradesmen temporary access to a house. A similar situation arises in offices and factories where staff, for example cleaners, require access to the premises outside office/working hours.

25 According to the present invention, there is provided a lock operable by two or more different keys, the lock

. 2 comprising: a bolt means movable between a locked position and an unlocked position; blocking means, responsive to the profile of a key 5 in engagement with the lock, for blocking movement of the bolt means between the locked position and the unlocked position unless the key has a predetermined profile; and selection means, movable between a first position and a second position, so that when the selection-means 10 is in the first position, the blocking means is responsive to the profile of a first key, whereas when the selection means is in the second position, the blocking means is responsive to the profile of a second key having a different profile to from of the first key.

In one embodiment the blocking means is a lever or a set of levers alignable by the key profile to permit movement of the bolt means, and the selection means comprises one or more elements selectively insertable between the lever 20 or levers and the key.

Embodiments of the invention will now be described by way of example with reference to the following drawings, in which: Figure 1 is an isometric view of a lock according to a

first embodiment, showing the lock mounted in a door; Figure 2 shows a householder's key and a tradesman's key (to be temporarily given to a tradesman by the 5 householder) key, different from the householder's, that may be used to operate the lock of Figure 1; I. Figure 3 shows a side view of the lock of Figure 1 (a side cover has been removed to allow the internal parts 10 to be seen); Figure 4 is a view of the lock of Figure 1, with the side cover removed, showing the lock configured for use with a householder's key and showing the householder's key 15 being used to operate the lock; Figure 5 is a cross-sectional view in the plane XX' of Figure 4 (and including the side cover), showing the interaction of the lock of Figure 1 with the 20 householder's key; Figure 6 is a view of the lock of Figure 1, with the side cover removed, showing the lock configured for use with << a tradesman's key and showing the tradesman's key being 25 used to operate the lock;

!' Figure 7 is a cross-sectional view in the plane YY' of Figure 6 (and including the side cover), showing the interaction of the lock of Figure 1 with the tradesman's key; Figure 8 is a view of a lock (with a side cover removed) according to a second embodiment configured for use with a tradesman's key showing a mechanism for changing the configuration of the lock that is different from the 10 mechanism of the first embodiment; Figure 9 is a perspective view of a lock according to a third embodiment showing a lock assembly (including the lock) mounted in a door; Figure 10 shows the householder's key and a tradesman's key, different from the householder's key, that may be used to operate the lock of Figure 9; 20 Figure 11 is a front perspective view of the lock of Figure 9 removed from the door, showing the keyhole of the lock; Figure 12 is a rear perspective view of the lock of 25 Figure 9 removed from the door, showing a knob for adjusting the lock between a householder Is configuration

and a tradesmans configuration; Figure 13 is a cross-sectional view, in the plane PP' of Figures 9, 11 and 12, showing the lock in the 5 householder's configuration and showing a householder's key inserted into the lock; Figure 14 is a cross-sectional view, in the plane QQ' of Figures 9 and 11 to 13, of the lock showing the lock in 10 the householder's configuration with no key inserted; and Figure 15 is a cross-sectional view, in the plane QQ' of Figures 9 and 11 to 13, of the lock showing the lock in the tradesman's configuration with no key inserted.

FIRST EMBODIMENT

- Figure 1 shows a lock 100 according to a first embodiment of the invention, mounted within a door 101. The lock 100 is a lever lock. The lock 100 has a front plate 102 which 20 is secured to the door 101 by two screws 103 which pass through screw holes 103h in the front plate 102. The lock 100 has a body 105 (shown in phantom lines). A bolt 104 is shown projecting out from the front plate 102; when the bolt 104 projects from the front plate 102 then 25 the lock 100 is locked whereas when the bolt 104 is retracted into the body 105 of the lock 100 then the lock

100 is unlocked.

A keyhole 106 is provided in the door 101 and this keyhole communicates with a corresponding keyhole 107 5 provided in a side plate 108 of the lock 100.

Corresponding keyholes (not shown) are provided on the other side of the door 101 and lock 100.

A knob 109 is used to place the lock 100 into-either a 10 "householder's" configuration, in which only a "householder's" key may be used to operate the lock 100, or into a "tradesman's" configuration, in which only a "tradesman's" key may be used to operate the lock 100.

The knob 109 is shown at one end of a slot 110 and in 15 this position the lock 100 is in the "householder's" configuration; when the knob 109 is at the other end of the slot 110 then the lock 100 is in the "tradesman's" configuration. The slot 110 is provided in the door 101 and the slot 110 communicates with a corresponding slot 20 111 provided in the side cover 108 of the lock 100. The knob 109 and slot 110 are on the "inside" of the door, i.e the side of the door inaccessible when the door is locked. 25 Figure 2 shows the "householder's" key 200a and the "tradesman's" key 20Ob.

In day-to-day use of the lock 100, the householder places the lock 100 in the householder's configuration by moving knob 109 away from front plate 102, and uses the householders key to lock/unlock the lock 100. When a 5 tradesman is to be allowed temporary access, the householder places the lock 100 in the tradesman's configuration by moving knob 109 toward front plate 102, and locks the lock 100 using the tradesman's key. The householder then temporarily gives a tradesman's key to 10 the tradesman (the householder retains a separate copy of the tradesmans key for himself) to allow the tradesman to unlock the door, carry out work, and lock the door on exit while the householder is away from the house. When the householder returns, he uses the 15 tradesman's key to enter the house and then places the lock 100 back in the householder's configuration by moving the knob 109 away from the front plate 102. The tradesman's key can then no longer be used to operate the lock 100.

The keys 200 are similar and each comprises a cylindrical shaft 201, a flange 202 provided on the shaft 201 to act as a depth-stop when either key 200 is inserted into the lock 100, and a key bit 203 extending radially outwardly 25 from the shaft 201. A centre line CL is shown along the axis of each of the shafts 201. Each of the key bits 203

is symmetrical (so that the door 101 can be locked or unlocked from either the Inside or the "outside" of the door) and each key bit 203 has a pair of bolt portions 204 (for extending and retracting the bolt 104 when the 5 lock 100 is being operated). Each of the key bits 203 also has a respective lever portion 205 for engaging with a lever (not shown) inside the lock 100. The householder's key 200a has a lever portion 205a which is spaced from the centre line CL by a radius rl whereas the 10 tradesman's key 200b has a lever portion 205b spaced from the centre line CL by a smaller distance, r2.

Figure 3 shows the lock 100 with the side cover 108 removed. Opposite the side cover 108 (not shown) is a 15 baseplate 301 to which the majority of the internal parts of the lock 100 are mounted. The baseplate 301 has a keyhole 307 which corresponds to the keyhole 107 provided in the side plate 108.

20 The bolt 104 is constrained to move between an extended position (shown) and a retracted position (not shown) by a bolt slot pin 302 which is mounted to the baseplate 301. A bolt slot 303 provided in the bolt 104 allows the bolt 104 to move relative to the bolt slot pin 302.

A lever 304 is mounted in front (in the view of Figure

3) of the bolt 104, and is pivotally mounted to the baseplate 301 by a lever pivot pin 305. The lever 304 has an.tH" shaped lever slot 306 which is engaged with a bolt lever pin 308. The bolt lever pin 308 is mounted to, and 5 projects out from, the bolt 104 and therefore the bolt 104 can only move between its extended position and its retracted position when the lever 304 is rotated to align a central portion 306c of the lever slot 306 with the bolt lever pin 308.

The lever 304 has a spring 309, formed in this embodiment from a strip of spring metal, projecting from it and this spring 309 bears against a spring pin 315 mounted to the baseplate 301. Thus the lever 304 is rotationally biassed 15 anticlockwise so that the central portion 306c of the lever slot 306 is not normally aligned with the bolt lever pin 308. However, by using the appropriate key 200, the lever 304 can be rotated clockwise by a small angle about the lever pivot pin 305 so that the central portion 20 306c is aligned with the bolt lever pin 308. When they are aligned, the bolt lever pin 308 may be moved from one end of the lever slot 306 to the other end, thereby allowing the bolt 104 to be extended or retracted.

25 The bolt 104 has a pair of bolt shoulders 320 which, when the central portion 306c of the lever slot 306 is aligned

with the bolt lever pin 308, allow the bolt portions 204 of the first and second keys 200 to slide the bolt 104 between the extended and retracted positions as the key is rotated. A notch 321 is provided at the intersection 5 of the two bolt shoulders 320. The notch 321 receives the tip of the bolt portions 204 of the keys 200 when a key 200 has been inserted into the lock 100 and turned by about 180 .

10 The bottom of the lever 304 has a radiussed portion 304r, of radius rl, for engaging with the lever portion 205a of the first key 200a. When the lever 304 is rotated clockwise by the small angle so that the central portion 306c of the lever slot 306 is aligned with the bolt lever 15 pin 308, then the radiussed portion 304r is concentric with a circular portion 307c of the keyhole 307.

The lever 304 has a pair of flat portions 304f on either side of the radiussed portion 304r. When one of the keys 20 200 is inserted into the keyhole 307 and rotated, the lever portion 205 of the key will be brought to bear against one of the flat portions 304f and will cause the lever 304 to rotate clockwise about the lever pivot pin 305 while the lever portion 205 moves along the flat 25 portion 304f. Further rotation of the key 200 will bring the lever portion 205 into contact with the radiussed

l. t'):L aim; portion 304r. If the correct key (in this case the householders key 200a) is being used then the lever 304 will be positioned with the central part 306c of the lever slot in alignment with the bolt lever pin 308. As 5 the lever portion 205a of the key contacts the radiussed portion 304r, the bolt portion 204 of the key contacts the shoulder 320. Continued clockwise rotation of the key causes the bolt portion 204 to move the bolt to the right (as seen in the Figure) while the lever portion 10 205a engaging the radiussed portion 304r of the lever 304 holds the lever in the correct orientation for bolt lever pin 308 to pass through the central part 306c of the lever slot 306. When the lever portion of the key reaches the right-hand end (as seen in Figure 3) of the 15 radiussed portion 304r, continued rotation of the key causes the lever to rotate anti-clockwise, trapping the bolt lever pin 308 in the right-hand part of the lever slot 306. The key is then rotated to the removal position (with the key bit 203 downward) and removed.

A configuration changer 310 is slidably movable by the knob 109 so that the lock 100 can be changed from the householder's configuration (shown in Figure 3) to the tradesman's configuration (shown in Figure 6). The 25 configuration changer 310 is held by two slide guides 313 which are mounted to the baseplate 301. The left-hand

end of the configuration changer 310 is curved so that an upper part forms a first radiussed portion 311, of radius rl, whilst a lower part forms a second radiussed portion 312, of radius r2. The second radiussed portion 5 312 is co-operable with the lever portion 205b of the second key 200b. The configuration changer 310 can be slid leftwards in order to place the lock 100 in the tradesman's configuration, in which case the first radiussed portion 311 engages with the radiussed portion 10 304r of the lever 306. The configuration changer 310 is made from spring metal, allowing it to bend as it is slid leftwards into engagement with the lever 304.

The configuration changer 310 has a pair of flats 310f 15 on either side of the second radiussed portion 312. When the first radiussed portion 311 is engaged with the radiussed portion 304r of the lever 304 then the flats 310f of the configuration changer 310 perform the same function as the flats 304f of the lever 304.

Figure 4 shows the lock 100 in the householder's configuration with the householder's key 200a inserted and with the bolt 104 halfway between its fully retracted and fully extended positions. To retract the bolt 104 25 from the extended position shown in Figure 3, the householder's key 200a is inserted into the lock 100

through the keyhole 307 and rotated 180 clockwise (as shown in the Figure) so that the key bit 203 points vertically upwards, as shown. As the key approaches this position, the lever portion 205a of the householder's key 5 200a co-operates first with one of the flat positions 304f and then with the radiussed portion 304r of the lever 304 and causes the lever 304 to rotate clockwise to align the central portion 306c of the lever slot 306 with the bolt lever pin 308. Further rotation of the 10 householder's key 200a to the position shown in Figure 3 causes one of the bolt portions 204 of the householder's key 200a to bear against the right-hand bolt shoulder 320 so that the bolt 104 is pushed to the halfway position shown. As shown in phantom lines, the 15 tip of the bolt portion 204 of the householder's key 200a is received by the notch 321 of the bolt 104.

Figure 5 shows a cross-section XX' through Figure 4 so that the relationship between the householder's key 200a, 20 the bolt 104 and the lever 304 may more readily be appreciated. The householder's key 200a has been inserted into the keyhole 307 until the flange 202 bears against the 25 exterior face of the base plate 301, and has been rotated by 180 so that the bolt 104 lies halfway between its

extended position and its retracted position. The circular portions 107c, 307c of the keyholes 107, 307 act as bearing surfaces and journal the shaft 201 of the key 200a so that the key 200a is accurately engaged with the 5 bolt 104 and the lever 304. As shown, one of the bolt portions 204 of the key bit 203 is engaged with the notch 321 of the bolt 104, whilst the lever portion 205a is engaged with the radiussed portion 304r of the lever 304.

10 Figure 6 shows the lock 100 in the tradesman's configuration with the tradesman's key 200b inserted and with the bolt 104 halfway between its fully retracted and fully extended positions. AS shown, the knob 109 has been used to slide the configuration changer 310 fully 15 leftwards so that the first radiussed portion 311 is engaged with the radiussed portion 304r of the lever 304.

The configuration changer 310 is formed, in this embodiment, from spring steel and can therefore bend as 20 it is moved leftwards against the lever 304. The flexibility of the configuration changer 310 also allows it to bend upwards when the lever 304 is rotated clockwise by the small amount. The configuration changer 310 is formed of metal of substantially the same 25 thickness, in this embodiment, as the thickness of the lever 304.

The configuration changer 310 changes the effective shape of the lever 304 so that the tradesman's key 200b can be used to operate the lock. Note that when the lock 100 is in the tradesman's configuration, the householder's 5 key 200a can no longer be used to operate the lock as the householders key 200a would cause the lever 304 to be rotated by more than the required amount due to the interposition between the key 200a and the lever 304 of the configuration changer 310; thus the bolt lever pin 10 308 would not be aligned with the central portion 306c of the lever slot 306.

Figure 7 shows a cross-section YY' through Figure 6 so that the relationship between the tradesman's key 20Ob, 15 the bolt 104 and the lever 304 may more readily be appreciated. As can be seen, the lever portion 205b of the tradesman's key 200b is radially shorter than the lever portion 205a of the householder's key 200a by an amount rl-r2. However, the configuration changer 310 20 makes up for the difference in radius between the lever portions 205a and 205b. Thus, when the configuration changer is in place between the lever 304 and the key 200b, the tradesman's key 200b can be used to rotate the lever clockwise by the correct angle so that the central 25 portion 306c of the lever slot 306 is aligned with the bolt lever pin 308.

SECOND EMBODIMENT

Figure 8 shows a second embodiment 800 of a lock. The lock 800 is similar to the lock 100 with which it shares common parts which have the same reference signs as for 5 the first embodiment 100. The bolt 104 is shown in the retracted position.

Whereas in the lock 100 the configuration changer 310 was slid leftwards (in order to change the effective radius 10 of the radiussed portion 304r of the lever 304 from a first radius, rl, to a second radius, r2), the lock 800 has a configuration changer 810 which is rotated about the lever pivot pin 305 in order to change the configuration. The lock 800 is shown in the tradesman's 15 configuration, the configuration changer 810 having been rotated clockwise until it bears against the lever 304.

The configuration changer 810 is similar to the configuration changer 310 and has a radiussed portion 20 810r and a pair of flat portions 810f. A knob 809 allows the configuration changer 810 to be rotated into or out of engagement with the lever 304. As shown, the knob 809 is mounted to the lever pivot pin 305 on top of the lever 304. The radiussed portion 810r and the flat portions 25 810f are in the same plane as the lever 304 and therefore a step 811 connects these to the knob 809 which is in a

different plane.

The configuration changer 810 may be rotated anti clockwise to a position (shown in phantom lines) remote 5 from the lever 304, in order to place the lock 800 in the householder's configuration. The configuration changer 810 does not need to be flexible and so need not be formed from, say, spring steel.

10 THIRD EMBODIMENT

Figure 9 shows a third embodiment of a lock. The lock 900 is mounted within a door 901 and comprises a body 905 (shown in phantom lines), a knob 910 (shown in phantom lines) and a cylinder 906. The cylinder 906 is rotatable 15 relative to the body 905 when either a householder's key or a tradesman's key is inserted into a keyhole 907 in the cylinder 906.

Figure 10 shows the householder's key 1000a and the 20 tradesmans key 1000b. The tradesman's key 1000b differs from the householder's key 1000a as its notch 1001c is deeper than the corresponding notch 1001c in the householder's key 1000a, as discussed later in more detail. Returning to Figure 9, the knob 910 projects out from the

door 901 (on the other side of the door to the keyhole 907) and can be rotated relative to the cylinder 906 in order to place the lock 900 in either a householder's configuration, in which the householder's key lOOOa can 5 be used to operate the lock 900, or in the tradesman's configuration, in which the tradesman's key lOOOb can be used to operate the lock.

Some ancillary components which are used in conjunction 10 with the lock 900 are partially or wholly mounted within the door 901 and are therefore are partially or wholly shown in phantom lines. A bolt crank 916 is attached to the cylinder 906 (at the end of the cylinder 906 opposite the keyhole 907) and rotates with the cylinder 906. The 15 bolt crank 916 is connected via a connecting rod 917 to a bolt 904 so that rotation of the cylinder 906 causes the bolt 904 to be either extended out of the door 901 or retracted into the door 901. The bolt 904 is shown in its retracted position. A bolt plate 902, secured by 20 screws 903 to the door 901, holds the bolt 904 in position. Figure 11 shows a view towards the front of the lock 900 and shows a keyhole slot 1107 (shown in phantom lines) 25 extending backwards from the keyhole 907. Five identical bores lOOla llOle (shown in phantom lines) are provided

in the body 905 and five identical bores 1102a - 1102e (shown in phantom lines) are provided in the cylinder 906. The bores 1102 intersect the keyhole slot 1107.

The bores 1102 are shown aligned with the bores 1101 but 5 if the cylinder 906 is rotated relative to the body 905 then the bores 1101 and bores 1102 will no longer be aligned. Figure 12 shows a view towards the rear of the lock 900 10 and shows the knob 910 projecting out from the rear of the cylinder 906. Also shown is a slot 1216 in the rear of the cylinder 906. The slot 1216 provides an attachment point for the bolt crank 916 and transmits torque from the cylinder 906 to the bolt crank 916.

Figure 13 shows a cross-sectional view, in the plane PP' of Figures 9, 11 and 12, through the lock 900. The householder's key lOOOa is shown fully inserted into the keyhole slot 1107. Note that the knob 910 does not lie 20 in the plane PP' and is therefore not shown.

Each bore 1101 holds a respective pin spring 1301 and a respective body pin 1302. The pin springs 1301 push the body pins 1302 towards the householder's key lOOOa. Each 25 of the bores 1102 holds a respective profile pin 1303 and a respective key pin 1304. The key pins 1304 are in

contact with the householder's key lOOOa while the profile pins 1303 lie between, and in contact with, their respective body pins 1302 and key pins 1304. Thus the pin springs 1301 urge the body pins 1302, the profile 5 pins 1303 and the key pins 1304 into contact with each other and towards the householder's key lOOOa.

Whereas the body pins 1302 have the same length as each other and the key pins 1304 have the same length as each 10 other, the profile pins 1303 have different lengths from each other. It is the lengths of the profile pins 1303 that determine the profile of the householder's key lOOOa. 15 In Figure 13, the householder's key lOOOa can be used to rotate the cylinder 906 relative to the body 905. This is because each of the body pins 1302 extends just as far as, and no further than, its respective bore 1101 and because each of the profile pins 1303 extends just as far 20 as, and no further than its respective bore 1302. Thus all five of the body pins 1302 and their respective profile pins 1303 meet at a "shear plane" 1300. "Shear plane' is a term used in the art to denote the position where the body pins 1302 and the profile pins 1303 must 25 meet in order to allow the cylinder 906 to rotate.

Strictly speaking, the shear plane 1300 is actually the

cylindrical surface at the boundary between the cylinder 906 and the body 905 but, in the vicinity of the bores 1101 and bores 1102, the shear plane may be regarded as an elongate planar region.

Note that if an incorrect key, having one or more flats 1001 that are too "low", were to be inserted into the lock 900 (or if no key were inserted at all), then some (or all) of the body pins 1302 would be pushed by the pin 10 springs 1301 towards the cylinder 906 and partially into the bores 1102. Those body pins 1302 would straddle the shear plane 1300, thus locking the bores 1101 to the bores 1102 and thus locking the cylinder 906 to the body 905. Conversely, if an incorrect key, having one or more 15 flats 1001 that are too 'thigh" (or if a key that took up the full height of the keyhole slot 1107) were to be inserted into the lock 900, then some (or all) of the profile pins 1303 would be pushed by the key towards the body 905 and partially into the bores 1101. Those 20 profile pins would straddle the shear plane 1300 thus locking the cylinder 906 to the body 905.

Figure 14 shows a cross-sectional view through the bores llOlc and 1102c in the plane QQ' of Figures 9 and 11 to 25 13. The lock 900 is in the householder's configuration.

Note that in Figure 14 the householder's key lOOOa has

been removed from the cylinder 906 and consequently the body pin 1302c, the profile pin 1303c and the key pin 1304c are pushed downwards by the pin spring 1301c until a frusto-conical face 1400 of the key pin 1304c is seated 5 on a pair of arcuate shoulders 1401 within the keyhole slot 1307. The body pin 1302c is straddling the shear plane 1300 and therefore rotation of the cylinder 906 relative to the body 905 is blocked.

10 In order to change the configuration of the lock 900 from the householder's configuration to the tradesman's configuration, a change pin 1402 is inserted between the profile pin 1303c and the key pin 1304c, as shown at Figure 15.

Figure 15 is similar to Figure 14 except that the lock 900 is in the tradesman's configuration and the change pin 1402 has been inserted. Consequently, the body pin 1302c and the profile pin 1303c have been displaced 20 upwards by a small distance corresponding to the thickness (i.e. length) of the change pin 1402. In this embodiment the change pin 1402 is discoidal as its diameter is greater than its length. The change pin 1402 is bevelled on one side to facilitate its insertion.

25 Similarly, the profile pin 1303c has a frusto-conical face to facilitate the insertion of the change pin 1402.

Figure 10 shows that the keys 1000 each have five flats lOOla - lOOle at the bottom of respective notches. The flats 1001 each cooperate with a respective key pin 1304 5 when one of the keys 1000 is inserted into the keyhole slot 1107. The notch for the flat lOOlc of the tradesman's key lOOOb is deeper than the notch for the flat lOOlc of the householder's key by a distance equal to the length of the change pin 1402.

Returning to Figures 14 and 15, the insertion of the change pin 1402 between the profile pin 1303c and the key :\ pin 1304c is achieved by a change slider 1403 which pushes the change pin 1402 along a rectangular slider 15 bore 1404. The rectangular slider bore 1404 intersects perpendicularly with the bore 1102c. In this embodiment the change pin 1402 and the change slider 1403 are each magnetised so that they are attracted to each other.

Thus the change slider 1403 bears against the change pin 20 1402 in order to push the change pin 1402 into the bore 1102c whereas the change pin 1402 is withdrawn from the bore 1102c by being magnetically pulled out of the bore 1102c. 25 The change slider 1403 is caused to move along the slider bore 1404 by an arm 1405 which extends radially outwards from a shaft 1406 and which is free to move within a sector chamber 1407.

The shaft 1407 runs parallel to the longitudinal axis of the cylinder 906. The shaft 1406 is connected to the knob 910 so that rotation of the knob 5 910 relative to the cylinder 906 causes the change pin 1402 to be either inserted into, or retracted from, the bore 1102c. If the shaft 1406 is rotated anti-clockwise with reference to Figure 14 (i.e. the knob 910 is rotated clockwise with reference to Figure 12) then the change 10 pin 1402 will be withdrawn from the bore 1102c and the lock 900 will be in the householder's configuration.

Conversely, if the shaft 1406 is rotated clockwise with reference to Figure 15 (i.e. the knob 910 is rotated anti-clockwise with reference to Figure 12) then the 15 change pin 1402 will be inserted into the bore 1102c and the lock 900 will be in the tradesman's configuration.

FURTHER EMBODIMENTS

The locks 100, 800 of Figures 1 to 8 each have a single 20 lever 304. As those skilled in the art will appreciate, lever locks often have a greater number of levers, for example 3 or 5, in order to make them more resistant to lock-picking. A lock having several levers 304 may be provided with one or more configuration changers 310, 25 810. Where several configuration changers are used then these may change the effective radius of their respective

levers 304 by different amounts or by a common amount.

However, where several configuration changers 310, 810 are used it is preferred that they change the radii of their respective levers 304 by different amounts as this 5 would make it harder for the profile of the householder's key 200a to be deduced from the tradesman's key 200b.

Where several configuration changers 310, 810 are used then these are preferably operated by a common knob 109, 809. Configuration changers 310, 810 may be provided for 10 one, some, or all the levers of a multi-lever lock.

The configuration changer 810 is mounted on the lever pivot pin 305. In an alternative embodiment, the configuration changer 810 may rotate about a different 15 axis, in which case the configuration changer 810 may need to be flexible to accommodate movement between it and the lever 304 as they move rotate about different axes. 20 The locks 100, 800 each have two configurations: a householder's configuration and a tradesman configuration. In alternative embodiments, a lock may be provided with three or more configurations. One way in which this could be done is by providing a modified 25 configuration changer having third and fourth radiussed portions as well as the first and second radiussed

portions 311, 312. Such a modified configuration changer could be selected to: i) not augment the lever 304, ii) to augment the lever 304 using the first and second radiussed portions 307, 312 or iii) to augment the 5 lever 304 using the third and fourth radiussed portions.

Alternatively, two or more independent configuration changers could be provided. The independent configuration changers may either change the effective shape of the same lever or of separate levers. Where a 10 lock has a plurality of levers and a plurality of respective configuration changers then three or more configurations for the lock may be provided by using two or more knobs where each knob actuates a subset of the configuration changers.

The locks 100, 800 had bolt shoulders 320 so that the - bolt 104 could be extended or retracted by one of the keys 200. In an alternative embodiment the bolt is provided with a handle to enable it to be extended or 20 retracted; in this embodiment the key 200 enables the bolt to be moved but does not actually move the bolt.

The lock 900 of Figures 9 et seq. has a single change pin 1402 which is inserted between the profile pin 1303c and 25 key pin 1304c. In alternative embodiments the change pin 1402 may be insertable between one of the other five

pairs of profile pins 1303 and key pins 1304.

!: Furthermore, whereas the lock 900 utilised a single change pin 1402, in alternative embodiments two or more change pins could be provided for two or more of the 5 bores 1102.

The configuration of the lock 900 is changeable using the knob 910 only when no key was present within the keyhole slot 1107. This was because it was necessary for the key 10 pin 1304c to be adjacent the shoulders 1401 in order to provide the correct alignment between the change pin 1402 and the profile pin 1303c. In an alternative embodiment the lock may be arranged so that the configuration of the lock can be changed only when the householder's key lOOOa 15 is inserted into the keyhole slot 1107. In this alternative embodiment, the pins nearest the key (formerly key pins 1304) have different lengths corresponding to the profile of the householder's key lOOOa whereas the other pins in the bores 1102 (formerly 20 profile pins 1303) have identical lengths.

The lock 900 has a generally rectangular keyhole 907 and a generally rectangular keyhole slot 1107. As those if. skilled in the art will appreciate, in alternative 25 embodiments the key and the keyhole slot may have a more complex cross-sectional shape which can obviate the

provision of the shoulders 1401 as such a more complex shape can be arranged to act as a stop to prevent the key pins 1304 from being pushed too far by the pin springs 1301 when no key is present in the keyhole slot 1107.

The lock 900 uses a magnetised change pin 1402 in conjunction with a magnetised change slider 1403. In alternative embodiments, a different arrangement of parts may be used to allow a change pin to be inserted into, 10 and extracted from, a cylinder bore 1102 and to allow the change pin to travel along the cylinder bore in response to a key inserted into the keyhole slot 1107. Such alternative embodiments may use lost motion arrangements that do not include magnetised parts.

The lock 900 has a single shaft 1407 with which a householder can set the lock 900 to either a householder's configuration or to a tradesman's configuration. In an alternative embodiment having two 20 or more change pins, two shafts are provided so that each shaft controls at least one change pin. A lock having two shafts would be configurable to one of four configurations: a householder's configuration, a first À tradesman's configuration with one shaft and its change 25 pins operating a second tradesman's configuration with the other shaft and its change pins operating and a third

tradesman's configuration with both shafts and all the change pins operating. Further shafts and change pins would allow still further configurations.

5 The lock 900 is operable by using a key 1000 inserted within a rotatable cylinder 906. In alternative embodiments, the functions of the bores 1101 and bores 1102 may be reversed so that a key 1000 is inserted into the body of the lock and a separate handle is used to 10 rotate the cylinder relative to the body. In such an embodiment the pin springs 1301 and the body pins 1302 are provided within the cylinder whereas the profile pins, 1303 the key pins 1304, the change pins 1402 and the change pin operating mechanism are provided (with the 15 keyhole slot 1107) in the body of the lock.

The lock 900 has a change pin 1402 which could either be inserted into, or extracted from, a bore 1102c. In an alternative embodiment, instead of using a change pin 20 1402 to change the effective combined length of the profile pin 1303c and key pin 1304c, a generally rectangular "double" pin may be used. In effect, the double pin comprises two pins of different length arranged side by side and joined together. One side of 25 the double pin has a first length while the other side of the double pin has a second length. The double pin

is slid transversely to the keyhole slot 1107 in order to select one or the other sides of the double pin.

Thus, when the double pin is in one position relative to the keyhole slot 1107, then it has a first effective 5 length whilst when it is in the other position then it has a second effective length. The double pin may be provided with a sloping "transition" region between the two sides to facilitate compression of the pin spring when the double pin is moved from the short effective 10 length position to the long effective length position.

The lock 900 has a shaft 1407 which is rotatable relative to the cylinder 906 in order to change the configuration of the lock 900. In an alternative embodiment, a slider 15 having an oblique slot may be slid longitudinally relative to the cylinder 906 in order to change the configuration of the lock. A change slider is arranged to cooperate with the oblique slot so that longitudinal motion of the slider causes the change slider to move 20 along within the slider bore 1404.

The lock 900 has profile pins 1303 and key pins 1304 within the cylinder 906. In an alternative embodiment, :, the key pins 1304 are dispensed with and the (suitably 25 lengthened) profile pins 1303 interact directly with the keys 1000. In such an embodiment, the position of the

slider bore 1404 relative to the bore 1102c is such that the change pin 1402 may be inserted underneath its associated profile pin 1303 so that the change pin 1402 acts as an intermediary between the profile pin 1303c and 5 a key inserted into the keyhole slot 1107.

The lock 900 uses a bolt crank 916 and a connecting rod 917 to allow rotation of the cylinder 906 to extend/retract the bolt 904. In alternative embodiments, 10 other mechanisms may be used, for example a cam and a cam plate. The lock 900 has a cylinder 906 which is rotatable relative to the body 905. In an alternative embodiment, 15 a cylinder slides longitudinally relative to the body and the longitudinal motion is used to extend/retract the bolt 904.

The locks 100, 800 and 900 were complete and did not 20 require further parts. As an alternative, a kit of parts may be provided for retrofitting to existing locks. For example, a configuration changer 310, 810 and a replacement side plate 108 may be provided in order to modify a conventional lever lock so that it operates in 25 a similar fashion to the locks 100,800. Replacement cylinder assemblies may be made available for modifying

conventional cylinder locks so that they operate in a similar fashion to the lock 900. The cylinder of the lock to be modified would be removed (this usually requires the insertion of the correct key) and replaced 5 by a cylinder similar to the cylinder 906.

The locks 100, 800 and 900 operated bolts 104, 904. In alternative embodiments the locks may be used to operate devices similar to a bolt, for example security-fasteners 10 such as espagnollettes provided at the top and bottom of a door. The locks may also be used to operate an electrical switch instead of physically restraining a door. The locks 100, 800 and 900 are suitable for incorporation into ready assembled doors thus removing 15 the need for a building contractor to assemble doors and locks on-site. Other applications for the locks are in desk drawers, automobiles and safes.

Claims (31)

1. A lock selectively operable by a first key having a first profile and by a second key having a second, 5 different, profile, comprising: selection means moveable between a first setting and a second setting; bolt means moveable when the first key or the second key is inserted into the lock; and 10 blocking means, cooperable with a key inserted into the lock and with the selection means, for blocking and unblocking movement of the bolt means so that when the selection means is at the first setting then insertion of the first key, but not the second key, can cause the 15 bolt means to be unblocked whereas when the selection means is at the second setting then insertion of the second key can cause the bolt means to be unblocked.

2. A lock according to claim 1, wherein the bolt means 20 comprises a bolt.

3. A lock according to claim 1 or 2, wherein the bolt means comprises an electrical switch.

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4. A lock according to any one of claims 1 to 3, wherein the blocking means comprises a lever engageable

by an inserted key and wherein the selection means comprises a configuration changer so that when the selection means is at the first setting then the configuration changer is spaced from the lever but when 5 the selection means is at the second setting then the configuration changer is positioned between the inserted key and the lever.

5. A lock according to claim 4, wherein the 10 configuration changer is slidably moveable.

6. A lock according to claim 4, wherein the lever is rotatably mounted to a pivot and the configuration changer is rotatably mounted to a pivot.

7. A lock according to claim 6, wherein the lever and the configuration changer are mounted to different pivots. 20

8. A lock according to any one of claims 4 to 7, wherein the bolt means comprises bolt shoulders, cooperable with an inserted key, for moving the bolt means. 25

9. A lock according to any one of claims 4 to 8, comprising two or more levers.

10. A lock according to any one of claims 4 to 9, comprising two or more configuration changers.

11. A lock according to claim 10, wherein at least two 5 configuration changers are each operable to change the effective shape of a lever, so that the selection means is moveable between three or more settings, and wherein the lock is operable by three or more respective keys.

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12. A lock according to any one of claims 1 to 3, wherein the bolt means comprises a body, and wherein the blocking means comprises a set of two pins, a key pin and a non-key pin, the lock comprising: a housing, wherein the body is mounted in the 15 housing and is moveable between a first position and a second position; a set of two alignable bores, one provided in the housing and the other provided in the body so that the bores are aligned when the body is in the first position, 20 wherein each pin is received in a respective one of the bores, the key pin is contactable by a key inserted into the lock, the pins are moveable along the bores in response to a key when the body is in the first position, and wherein the body is moveable from the first position 25 when the key pin is co-terminous with its respective bore,

wherein the selection means comprises a configuration changer for changing the effective length of the key pin so that when the selection means is at a first setting then the key pin has a first effective 5 length in the axial direction of the respective bore whereas when the selection means is at a second setting then the key pin has a second, different, effective length. 10

13. A lock according to claim 12, wherein the body comprises a keyhole for inserting a key.

14. A lock according to claim 12, wherein the body comprises a cylinder rotatably mounted in the housing.

15. A lock according to claim 14, wherein a slot for attaching a bolt crank to the cylinder is formed in the cylinder. 20

16. A lock according to claim 14 or 15, wherein the bolt means comprises a bolt crank, a connecting rod and a bolt.

17. A lock according to any one of claims 12 to 16, 25 wherein the configuration changer comprises a change pin which is removably insertable at one end of the key pin

into one of the bores.

18. A lock according to any one of claims 12 to 16, further comprising a profile pin provided between the key 5 pin and the non-key pin in one of the bores, wherein the configuration changer comprises a change pin which is removably insertable between the key pin and the profile pin. 10

19. A lock according to claim 17 or claim 18, comprising a change slider for removably inserting the change pin and for allowing the change pin to move relative to the change slider when the change pin has been inserted.

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20. A lock according to claim 19, wherein the change slider and the change pin have a magnetic attraction towards each other.

21. A lock according to any one of claims 12 to 20, 20 wherein the lock comprises two or more sets of pins and two or more respective sets of bores.

22. A lock according to any one of claims 17 to 21, comprising two or more change pins.

23. A lock according to claim 22, wherein two or more

change pins are insertable into a single bore.

24. A lock according to any one of claims 12 or 23, wherein the selection means is moveable between three or 5 more settings, and wherein the lock is operable by three or more respective keys.

25. A lock according to any one of claims 1 to 24, in combination with a first key and a second key.

26. A door fitted with a lock according to any one of claims 1 to 25.

27. A kit of parts for modifying a lever lock, the kit 15 of parts comprising: a configuration changer selectively engageable with a lever of the lock; and a selection means movable between a first setting and a second setting, so that when the selection means 20 is at the first setting then the configuration changer is spaced from the lever whereas when the selection means is at the second setting then the configuration changer is positioned between a key inserted into the lock and the lever.

28. A kit of parts for modifying a cylinder lock, the

kit of parts comprising: a first key and a second, different, key; a cylinder having bores and a key slot; key pins receivable by respective ones of the bores 5 and contactable by a key; a change pin removably insertable into one of the bores at one end of the respective key pin to change the effective length of the respective key pin; selection means moveable between a first setting and 10 a second setting, wherein when the selection means is at the first setting then the change pin is not inserted, and upon insertion of the first key into the key slot, the ends of the pins remote from the key are co-terminous with the 15 ends of their respective bores remote from the key, whereas when the selection means is at the second setting then the change pin is inserted, and upon insertion of the second key into the key slot, the ends of the pins remote from the key are co-terminous with the 20 ends of their respective bores remote from the key.

29. A lock as hereinbefore described and/or with reference to Figures 1, 2, 3, 4, 5, 6 or 7.

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30. A lock as hereinbefore described and/or with reference to Figures 1, 2 or 8.

31. A lock as hereinbefore described and/or with reference to Figures 9, 10, 11, 12, 13, 14 or 15.