GB2391898A

GB2391898A - Locks resisting unauthorised use

Info

Publication number: GB2391898A
Application number: GB0218475A
Authority: GB
Inventors: Robert William Walker; Mervin John Caddick
Original assignee: Era Products Ltd; Laird Security Hardware Ltd; ERA PRODUCTS Ltd
Current assignee: ERA PRODUCTS Ltd
Priority date: 2002-08-08
Filing date: 2002-08-08
Publication date: 2004-02-18
Anticipated expiration: 2022-08-08
Also published as: GB0218475D0; GB2391898B

Abstract

A lock comprises a casing 10 with spaced first and second side plates 11,14 including respective registering keyholes. A key cam 31 is rotatably mounted on inwardly projecting portions 29,30 of the first and second side plates and so the ends of the key cam are not accessible from the outside of the casing. In addition, the locking mechanism within the casing includes a bolt 22 extendible from and retractable into the casing by operation of the lock mechanism. The surfaces of the bolt that extend from the casing are provided with hardened plates 58 to prevent the bolt being cut. When a eurocylinder lock is used the throw of the bolt is increased by the use of an intermediate drive transfer member arranged between a locking member and the bolt. The locking member is rotatable about an axis to one side of the linear path of the bolt and the drive transfer member is movable by the locking member along an arcuate path having a radius greater than the radius of rotation of the locking member. Thus, in this way, the limited rotational movement of the locking member is translated into greater linear movement of the bolt.

Description

LocKs 2391 898 The invention relates to locks.

5 One form of lock comprises a casing containing a lock mechanism. In one fonn of such a lock, keyholes are provided on either side of the casing and it is a problem that tools can be inserted through the keyhole to actuate the lock mechanism to permit unauthorized entry through a closure such as a door and window incorporating the lock. In order to try and prevent this, it is known to provide a key cam which is 10 rotatably mounted between keyholes of the casing with the ends of the key cam exposed on the outer surfaces of the casing. This has the disadvantage that access to the key cam can be gained from outside the casing.

According to a first aspect of the invention, there is provided a lock comprising a 15 casing including spaced first and second side plates and containing a lock mechanism, each side plate including a respective keyhole with the two keyholes being in register, a key cam being provided for receiving and rotating with a key inserted into one or other of the keyholes, the key cam being rotatably mounted on inwardly projecting portions of the first and second side plates.

Such locks commonly include a bolt which is extendible from and retractable into the casing. The bolts are often cast of a relatively soft metal and, when extended, the

metal can be sawn through to release the lock.

According to a second aspect of the invention, there is provided a lock comprising a casing containing a lock mechanism including a bolt, the bolt being extendible from 5 and retractable into the casing by operation of the lock mechanism, the bolt including spaced side surfaces, at least one of said side surfaces carrying a hardened plate, at least part of said hardened plate being outside the casing when the bolt is extended from the casing.

10 The distance the bolt extends from the casing is also a security feature since the furler the bolt can extend from the casing the more it can engage in a corresponding keep and this increases the resistance of the lock to forced opening. Where the bolt is key-operated, the length of throw of the bolt is limited by the limited radius about which the key rotates.

According to a third aspect of the invention, there is provided a lock comprising a casing containing a bolt extendible and retractable along a linear path out of an into the casing, a lock mechanism including a locking member rotatable about an axis to one side of said linear path and a drive transfer member arranged between the locking 20 member and the bolt and movable by the locking member in an arcuate path having a radius greater than the radius of rotation of the locking member, the drive transfer member converting rotation of the locking member into extending and retracting

movement of the bolt.

The following is a more detailed description of some embodiments of the invention,

by way of example, reference being made to the accompanying drawings in which: Figure 1 is a side elevation of a lock and a second side plate of a casing of the lock removed to reveal a locking mechanism, Figure 2 is a side elevation of the lock of Figure 1 with the second side plate replaced 10 and all of the locking mechanism except a key cam removed, Figure 3 is a section on the line XX of Figure 2 and showing the mounting of the key cam in the casing, 15 Figure 4 is a perspective view of the lock of Figure 1 with the second side plate replaced and with the casing partly sectioned to reveal the locking mechanism including the key cam, Figure 5 is a perspective view of the lock of Figure 1 with the second side plate 20 replaced but the remainder of the casing removed and certain parts of the locking mechanism removed to show the key cam engaging a deadbolt of the lock,

Figure 6 is a perspective view of the deadbolt of Figures 1 to 5 showing in exploded view hardened plates for attachment to the deadbolt, Figure 7 is a side elevation of an alternative form of lock with a second side plate of 5 the casing of the lock removed and with most of the lock mechanism removed except a drive transfer member, Figure 8 is a similar view to Figure 7 but showing also the inclusion of a deadbolt, 10 Figure 9 is a similar view to Figure 8 but with the addition of a detainer, Figure 10 is a view of the lock of Figures 7, 8 and 9 from the opposite side of the casing, and 15 Figure 11 is a perspective view of the lock of Figures 7-10 from the other side with the second side plate present and the remainder of the casing removed and showing the drive transfer member and a bolt.

Referring first to Figure 1, the lock comprises a casing indicated generally at 10 20 formed by a first side plate 11 with an upstanding wall 12 extending along side and rear edges ofthe plate 11. A front plate 13 is attached to a front edge of the first side plate 11 and lies in a plane normal to the plane of the first side plate 11. The casing

is closed by a second side plate 14 of similar shape to the first side plate 11 and best seen in Figures 2 and S. The casing 10 contains a locking mechanism. The mechanism includes a boss 15 5 rotatably mounted on the first side plate 11 and including a central square cross section hole 16 for receiving a handle-operated drive bar (not shown). The boss 15 includes a radially extending arm 17 that is connected to an inner end of a bolt 18.

The outer end of the bolt extends through a hole in the front plate 13 and carries a roller 19 rotatable about an axis parallel to the plane of the front plate 13. coil 10 spring 20 acts between the bolt 18 and a post 21 on the first side plate 11 with the arrangement being such that rotation of a handle turns the spindle which in turn rotates the boss in a clockwise direction as viewed in Figure 1 to retract the roller 19 against the action of the spring 20. Release of the handle rotates the boss 15 in a counter clockwise direction as viewed in Figure 1 under the action of the spring 20 to extend 15 the bolt 18. These parts are described only briefly for they do not form part of the invention. The locking mechanism also includes a second bolt in the form of a deadbolt 22. The deadbolt 22 is mounted for rectilinear sliding movement relative to the casing between 20 an extended position shown in Figure 1 and a retracted position (not shown) in which the deadbolt 22 lies within the casing. The deadbolt 22 has an outer end that projects from the casing 10 in the extended position and an inner end that always lies within

the casing 10. As seen in Figure 5, the inner end carries a peg 23 that engages in a slot 24 in the first side plate 11 (see Figure 1) to guide the deadbolt 22 in its movement between the extended and retracted positions.

5 Referring next to Figure 6, the deadbolt 22 is cast from a metal such as brass and the outer end is of generally rectangular cross-section with two side faces 53,54. Each side face 53,54 is formed with a respective generally rectangular depression, one of which is shown at 55 in Figure 6. Within each depression are a pair of spaced pins 56 (see also Figure 5). Each pair of pins 56 is located in the associated depression 55 10 towards the inner end ofthe deadbolt 22. Two hardened plates 57,58 are sized to fit in respective depressions 55 and are each provided with a respective pair of holes 59,60 that receive the associated pins 56 to mount the hardened plates 57,58 on the associated side face 53,54.

15 As seen in Figure 1, where the deadbolt 22 is extended from the casing 10, the hardened plates 57,58 are partially extended from the casing 10, although the pins 56 remain within the casing 10. In use, the hardened plates 57,58 will be in a gap between a closure such as a door, carrying the lock and a keeper on an associated frame. The hardened plates 57,58 provide additional resistance against the deadbolt 20 22 being sawn to release the lock. The pins 56 are not accessible because they are within the casing 10.

Of course, the pins 56 could be on the hardened plates 57,58 and the holes 59 could be in the deadbolt 22. Alternatively, the hardened plates 57,58 could be connected to the deadbolt 22 in any other convenient way.

5 The locking mechanism also includes a plurality of conventional levers 25 that can be raised or lowered against the action of respective springs 26 to allow extending and retracting movement of the deadbolt 22. Since these parts and their operation are conventional, they will not be described in detail.

10 The first side plate 11 and the second side plate 14 include respective keyholes 27,28 (see Figures 1 and 2). The keyholes 27,28 are in register. Each keyhole comprises a part-circular portion 27a,28a leading to an elongate portion 27b,28b. The inner periphery (i.e. the periphery within the casing 10) of each part-circular portion 28a,28b is surrounded by a part-circular, inwardly directed flange 29,30. The two 15 flanges mount between them a key cam 31 best seen in Figures 1,3, 4 and 5. The key cam 31 comprises a central tubular portion 32 surrounded at one end by a disc-shaped portion 33. The diameter of the tubular portion 32 is similar to the diameter of the part-circular portions 27a, 28a of the keyholes 27,28 and the disc-shaped portion 33 includes an elongate slot 34 with similar shape to the elongate slots 27b,28b in the 20 keyholes 27,28. Each end of the tubular portion is provided with a respective annular rebate 35,36 and each rebate receives a respective flange 29,30. The key cam 31 is thus mounted for rotation about an axis co-axial with the axis of the part-circular holes

27a,28a of Me keyhole 27,28. In addition, as seen in Figures 1 and 4, there is a rest position of the key cam 31 where a key cam slot 34 and the tubular portion 32 are in register with the keyholes 27,28.

5 As best seen in Figure S. a lug 37 projects from the disc 33 inwardly of the casing 10 at the end of the slot 34 remote from the tubular portion 32. The purpose of this will be described below. As also seen in these drawings, the disc 33 is closely adjacent the first side plate 11. As best seen in Figure 1, the disc-shaped part 33 has an outer periphery that is not circular. Rather, it is provided with two straight portions 38,39.

10 One arm of a U-shaped leaf spring 40 bears against one of the straight portions 38 when the key cam 31 is in the rest position so tending to maintain the key cam 31 in the rest position.

In use, a key (not shown) of conventional kind is inserted into one or other of the 15 keyholes 27,28 and is then rotated in a clockwise direction as viewed in Figure 1. The key engages the tubular portion 32 of the key cam 31 to rotate the key cam 31 with the key against the action of the leaf spring 40. The key raises the levers in conventional fashion and the lug 37 engages in a recess 41 (see Figure 5) in the inner end of the deadbolt 22 so that the deadbolt 22 is retracted by continued rotation of the key until 20 the deadbolt 22 lies within the casing 10. The lug 37 then disengages from the recess 41 and the key and the key cam 31 continue to rotate together until the key cam 31 reaches the rest position when the key can be withdrawn.

Insertion of the key into one or other of the keyholes 27,28 and rotation in an anti-

clockwise direction as viewed in Figure I reverses the operation, lifting the levers and extending the deadbolt by engagement of the lug 37 in the recess 42.

5 The presence of the key cam 31 provides a safety feature which prevents the lock being picked by the insertion of tools through the keyholes 27, 28. The presence of the tubular portion 32 prevents such access. In addition, the mounting of the key cam 31 by engagement of the flanges 29, 30 with the tubular portion 32 provides an additional safety feature because no portion of the key cam 31 is exposed at the 10 interior of the casing and this reduces the possibilities of interference with the key cam 31. In addition, it results in the key being supported by the first side plate 11 and the second side plate 14 so making the location of the key more accurate. Of course, if an attempt is made through either keyhole 27,28 to rotate the key cam 31, the disc shaped part 32 simply covers the keyhole 27,28.

In addition, although the flanges 29,30 are shown in the drawings as being formed by the material of the first side plate 11 and the second side plate 14, by, for example, a punching operation, this need not be the case. The flanges 29,30 could be fanned separately and welded to the first and second side plates 11, 14. In addition, the 20 flanges 29,30 need not be continuous; they could be interrupted. Further, the connection between the key cam 31 and the first and second side plates need not be by the use of the flanges 29,30 and the rebates 35,36. The key cam could be mounted

on any inwardly projecting portions provided on the first and second side plates 11,12.

For example, the first and second side plates 11,14 could be provided with respective tubular portions into which respective ends of the tubular portion 32 fit.

5 Referring now to Figures 7 to l l, the second form of lock has a casing 10 generally identical to the casing l O of the lock of Figures 1 to 6 The casing contains a locking mechanism including a boss and bolt similar to the boss 15 and the bolt 18 shown in Figures l to 6 but absent from Figures 7 to 11 for clarity. The lock of Figures 7 to 11 is, however, designed for use with a standard eurocylinder lock (not shown). Such a 10 eurocylinder lock comprises a body with an elongate cylindrical portion and a depending elongate portion of rectangular cross-section which together form a housing of generally keyhole-shaped cross-section. The housing contains a key operated locking mechanism with rotation of the key rotating a lug projecting from the cylindrical portion around an arcuate groove intermediate the ends of the cylindrical 15 portion. In order to accommodate such a eurocylinder lock, the first side plate 11 and the second side plate 14 of the lock of Figures 7 to 11 are formed with registering correspondingly shaped keyholes 42,43 as seen in Figures 7 to 11.

As seen in Figure 11, the face of the inner end of the deadbolt 22 adjacent the first 20 side plate I 1 is provided with a recessed portion 44 from which projects a peg 45 that is received in the slot 24 in the first side plate 11 to guide Me deadbolt 22 in rectilinear sliding movement between the extended and retracted positions. In addition, as best

seen in Figure 7, this peg also engages a drive transfer member 46.

The drive transfer member 46 is a generally A-shaped member with a central hole 47 and two legs 48. As seen in Figure 11, the peg 45 extends through the central hole 47 5 and the central hole is larger than the peg 45 to allow the drive transfer member 46 both to rotate relative to the peg 45 and to move relative to the peg in directions normal to the direction of extending and retracting movement of the deadbolt 22. The purpose of this will be described below.

10 On the side of the drive transfer member 46 facing the first side plate 1 1, each leg 48 is provided with a respective lug 49. The lugs 49 are received in an arcuate slot 50 provided in the first side plate and best seen in Figures 7 to 9. As seen in those Figures, the arcuate slot 50 lies between the straight slot 24 and the keyhole 42. The centre of the arcuate slot 50 lies on a line normal to the length of the slot 24 and 15 passing through the centre of the circular portion of the keyhole 42. The radius of the arcuate slot 50 is greater than the radius of the circular portion of the keyhole 42. The drive transfer member 46 is thus constrained to travel to and fro along the arcuate slot 50. 20 With a eurocylinder lock extending through the keyholes 42,43, the lock operates as follows, assuming the deadbolt 22 is in the extended position shown in Figures 7 to 11. A key is inserted into the eurocylinder lock, from either end, and rotated

clockwise as viewed in Figures 7 to 10. This rotates the eurocylinder lock lug clockwise until it enters a recess 51 formed between the legs 48 of the drive transfer member. Continued rotation of the eurocylinder lug then causes the drive transfer member 46 to move in an arcuate path along the arcuate slot 50 under the control of 5 the lugs 49 on the legs 48. This movement is transmitted to the deadbolt 22 through the hole 48 and the peg 45 so moving the deadbolt 22 from the extended position to a retracted position in which the deadbolt 22 lies within the casing 10. As the drive transfer member 46 reaches the inner end of the arcuate slot 50, the eurocylinder lug leaves the recess 51.

It will be appreciated that during the arcuate movement, the drive transfer member both rotates relative to the peg 45 and moves in a direction normal to the length of the slot 24. This is accommodated by movement of the peg 45 in the hole 47. The deadbolt is moved from the retracted to the extended position by anti-clockwise 15 rotation of the key, as viewed in Figures 7 to 9. Anti-clockwise rotation of the eurocylinder lug engages the lug with the recess 51 in the drive transfer member 46 and moves the drive transfer member 46 back along the arcuate slot 50 with this movement being transmitted to the peg 45 to move the deadbolt 22 out of the casing.

This continues until the drive transfer member 46 reaches the end of the arcuate slot 20 when the deadbolt 22 is fully extended.

The benefit of the drive transfer member 46 is that it allows the deadbolt 22 to have a longer movement than would otherwise be the case. The lug of the eurocylinder lock rotates generally about the axis of the circular portion of the keyholes 42,43.

This limits the maximum rectilinear movement that can be achieved by a direct 5 connection between the eurocylinder lug and the deadbolt 22. By providing the drive transfer member 46 which moves in an arc having a larger radius than the radius of movement of the eurocylinder lug, the throw can be increased significantly.

Increasing the length of throw increases the extent to which the deadbolt 22 can engage in a corresponding keep and so provides additional security.

It will be appreciated that the interconnection between the drive transfer member 46 and the deadbolt 22 need not be by the peg 45 and the hole 47. Any suitable form of interconnection could be used; for example, the hole could be provided on the deadbolt 22 and the peg on the drive transfer member 46. Other forms of 15 interconnection are possible.

In addition, the drive transfer member 46 need not be moved by a cam on a eurocylinder lock. It could be moved by any key-operated means.

Claims

1. A lock comprising a casing including spaced first and second side plates and containing a lock mechanism, each side plate including a respective keyhole with 5 the two keyholes being in register, a key cam being provided for receiving and rotating with a key inserted into one or other of the keyholes, the key cam being rotatably mounted on inwardly projecting portions of the first and second side plates.

2. A lock according to claim I wherein the key cam includes a tubular portion 10 extending between the side plates, and having first and second ends, the first end including a recess receiving a projection on the first side plate and the second end including a recess receive a projection on the second side plate.

3. A lock according to claim 2 wherein each keyhole includes a partcircular 15 portion, each part-circular portion being surrounded by an inwardly-projecting part circular flange forming the projection received by the associated end of the tubular portion of the key cam.

4. A lock according to claim 3 wherein the first and second side plates are 20 formed from sheet metal, the flanges being formed from said sheets by a pressing operation.

5. A lock according to any one of claims 2 to 5 wherein the key cam includes a generally disc-shaped portion surrounding and connected to the tubular portion, the disc-shaped portion including a cut-out normally aligned with the keyholes, the disc shaped portion rotating with a key inserted into either keyhole to close at least one of 5 said keyholes during said rotation.

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

10 7. A lock comprising a casing containing a lock mechanism including a bolt, the bolt being extendible from and retractable into the casing by operation of the lock mechanism, the bolt including spaced side surfaces, at least one of said side surfaces carrying a hardened plate, at least part of said hardened plate being outside the casing when the bolt is extended from the casing.

8. A lock according to claim 7 wherein the hardened plate is mounted on the bolt by mounting means, the mounting means being within the casing when the bolt is in the extended position.

20 9. A lock according to claim 8 wherein the mounting means comprise a set of pins and a set of holes, one set being provided on the bolt and the other set being provided on the hardened plate, the pins being received in the holes.

10. A lock according to claim 9 wherein the set of pins are on the bolt and the set of holes are on the hardened plate.

A lock according to claim 10 wherein the bolt is formed by a casting 5 process, the pins being formed during the casting process.

12. A lock according to any one of claims 7 to 11 wherein the hardened plate is received in a recess provided on the associated side surface of the bolt.

10 13. A lock including a hardened plate substantially as hereinbefore described I with reference to the accompanying drawings.

14. A lock comprising a casing containing a bolt extendible and retractable along a linear path out of an into the casing, a lock mechanism including a locking 15 member rotatable about an axis to one side of said linear path and a drive transfer member arranged between the locking member and the bolt and movable by the locking member in an arcuate path having a radius greater than the radius of rotation of the locking member, the drive transfer member converting rotation of the locking member into extending and retracting movement of the bolt.

15. A lock according to claim IS wherein the bolt includes a pin projecting from a surface lying in a plane normal to the axis of rotation of the drive transfer

1, member and the drive transfer member including an aperture receiving said pin, the aperture engaging the pin to move the bolt and allowing movement of the pin within the aperture to accommodate relative movement between the bolt and the drive transfer member.

17. A lock according to claim 16 wherein the pin is guided in a rectilinear slot in the casing to constrain the bolt to movement in said linear path.

18. A lock according to any one of claims 14 to 17 wherein the drive transfer 10 member is guided by the casing in said arcuate path.

19. A lock according to claim 18 wherein the drive transfer member is guided along an arcuate slot provided in the casing.

15 20. A lock according to claim 19 wherein the drive transfer member includes at least one lug received in said arcuate slot to guide the drive transfer member.

21. A lock according to claim 20 wherein two such lugs are provided.

20 22. A lock according to-any one of claims 14 to 21 wherein the locking member includes a projection and the drive transfer member includes a recess receiving said projection as the projection rotates to move the drive transfer member in said arcuate

path, the projection then leaving the recess.

23. A lock according to claim 22 wherein said projection is part of a key operated cylinder lock.

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