GB2458681A

GB2458681A - Locking mechanism comprising cam member and lever mechanism

Info

Publication number: GB2458681A
Application number: GB0805591A
Authority: GB
Inventors: Steven Frank Wilkes
Original assignee: ERA PRODUCTS Ltd
Current assignee: ERA PRODUCTS Ltd
Priority date: 2008-03-27
Filing date: 2008-03-27
Publication date: 2009-09-30
Anticipated expiration: 2028-03-27
Also published as: GB0805591D0; GB2458681B

Abstract

A locking mechanism comprises a cam 11 rotatable about an axis 50 to operate a lock, a key 12 rotatable to rotate the cam, and a lever mechanism which receives the key and controls rotation of the key. A further mechanism operable to rotate the cam may be provided. Each mechanism may be provided in a housing 10a, 10b on either side of the cam. A clutch 22 may be associated with the cam and the lever mechanism, insertion of the key into the lever mechanism engaging the clutch to transmit rotation of the key to the cam. A further clutch may be associated with the cam and the further mechanism. The further mechanism may be a thumb turn (60, Fig. 8) or another lever mechanism. Levers 28-32 of the or each lever mechanism may each comprise a formation 36-38 which co-operates with a talon 39 to control movement of the levers. The locking mechanism may be used in place of a "Euro Cylinder" lock. Also disclosed is a lock system comprising one or more securing members moveable by rotation of a cam, the cam being rotated by a locking mechanism as previously described.

Description

* 2458681

LOCKING MECHANISMS

The invention relates to locking mechanisms.

Locking mechanisms are used to operate a lock. In a mortise lever lock, for example, rotation of a key lifts a plurality of levers allowing the key to engage and throw a bolt.

An alternative mechanism used in a mortise lock, for example, includes a pin-cylinder lock such as a so-called Eurocylinder in which a key-operated cylinder lock mechanism is used to rotate a cam that in turn throws a bolt. Locks operated by a pin-cylinder mechanism are popular because the cylinder is easily fitted to the lock (or changed) and thumb-turn knobs can be used in place of the internal key. However, they are vulnerable to attack because the cylinder can be broken or picked in a number of ways.

According to a first aspect of the invention there is provided a locking mechanism comprising a cam member rotatable about an axis to operate a lock, a key rotatable to rotate the cam member and a lever mechanism receiving the key and controlling rotation of the key.

Such a locking mechanism can be used as a replacement for a pin-cylinder lock providing the additional security of a lever mechanism.

According to a second aspect of the invention, there is provided a lock or multi-point lock system comprising one or more bolts or other securing members movable between a retracted inoperative position and secured in said extended operative position on rotation of the said cam member, the cam member being rotated by a locking mechanism according to the first aspect of the invention.

According to a third aspect of the invention, there is provided a lock or multi-point lock system comprising one or more bolts or other securing members movable between a retracted inoperative position and an extended operative position, at least one of said movements being controlled by movement of a cam member, the cam * 2 member being rotated by a locking mechanism according to the first aspect of the invention.

The following is a more detailed description of an embodiment of the invention, by way of example, reference being made to the accompanying drawings in which: Figure 1 is a side elevation of a lever operated locking mechanism including two lock units for rotating a cam, Figure 2 is a partially exploded view of one lock unit of the lever locking mechanism of Figure 1.

Figures 3a, 3b and 3c are different sections through the lock unit of Figure 2 showing the positions of respective levers of the unit when the key is in a rest position, Figures 4a and 4b are respective partial cross-sectional views of part of the locking mechanism of Figures 1, 2 and 3a to 3c showing a clutch of the locking mechanism, in Figure 4a with a key inserted from one side of the locking mechanism and in Figure 4b with a key inserted from the other side of the locking mechanism, Figures 5a, Sb and Sc are similar views to Figures 3a, 3b and 3c but showing the positions of the levers with the key in an initial rotation, Figures 6a, 6b and 6c are similar views to Figures 3a, 3b and 3c but showing the positions of the levers with the key in an intermediate rotation, Figures 7a, 7b and 7c are similar views to Figures 3a, 3b and 3c but showing the positions the levers with the key rotated through 1800, and Figures 8a and 8b are respective cross-sections of part of a modified form of the locking mechanism of figure 1 in which one lock until is replaced by a thumb-turn * 3 and showing, in Figure 8a, the position of a clutch of the mechanism before insertion of a key and, in Figure 8b, the position of the clutch after insertion of a key.

Referring first to Figure 1, the lever operated locking mechanism comprises two lock units lOa, lOb with a locking cam II between them that is rotatable about an axis 50 on operation of either mechanism IOa, lOb by a key 12 of conventional type including bits on the blade.

One lock unit IOa is shown in Figure 2 and comprises a housing 13 formed by a front plate 14 and a rear plate 15 interconnected by a side wall 16. The front plate 14 includes a lower portion 17 formed with a keyhole 18 and an upper generally rectangular portion 19. A mounting block 20 is formed at the lower end of the housing 13.

The lower part of the housing 13 contains a generally cylindrical key cam 21 mounted for rotation in the housing 13. The key cam 21 is connected to the locking cam 11 by a clutch 22, discussed in more detail below. The key cam 21 includes a slot 23 opening onto the exterior of the key cam 21 for receiving the key 12. The exterior surface of the key cam 21 includes a radially projecting lug 24 at the end of the slot 23 and a notch 25 spaced from the lug by 180°.

The upper part of the housing 13 contains a lever mechanism formed by seven side-by-side levers 27, 28, 28, 30, 31, 32, 33. Each lever 27-33 is generally rectangular, lies in a respective plane normal to the cam axis 50 and is a sliding fit in the upper part of the housing 13 for movement towards and away from the key cam 21. Each lever 27-3 3 is urged towards the key cam 21 by respective S-shaped springs 34 acting between the associated lever 27-33 and the housing 13.

The first and seventh levers 27, 33 are identical and include respective angled slots 35. In addition, these levers 27, 33 are each formed at their lower ends with a V-shaped projection 44. The second to sixth levers 28-32 are of differing lengths and each have a central vertical slot 36 and first and second horizontal notches 37, 38 on respective opposite sides of the central slot 36 and at differing spacings along the * 4 central slot 36. Each of these levers 2 8-32 has a concavely curved lower end 45 for engagement with the key bits. The way in which these levers 28-32 and the slots 36, 37, 38 are arranged will be discussed in more details below.

A talon 39 extends between a front guide plate 40 carried by the front plate 14 and the rear wall plate 15 of the housing. The front guide plate 40 and the rear plate 15 include respective horizontal slots 42, 43, with each end of the talon 39 being received in a respective slot 42, 43, so constraining the talon 39 for horizontal sliding movement in the slots 42, 43. The talon 39 extends through the angled slots 35 of the first and seventh levers 27, 33 and through the slots 36 in the second to sixth levers 28-32.

Referring next to Figures 3a, 3b and 3c, in the rest position of the lock mechanism, the key cam 21 is located with the slot 23 and the lug 24 facing downwardly and with the V-shaped projections 44 on the first and seventh levers 27, 33 engaging in the notches in the key cam 21. The lower ends 45 of the second to sixth levers 28-32 are urged by their respective springs 34 into engagement with a central tube 46 of the key cam 21. In this position, the first horizontal notches 37 of the second to sixth levers 28-32 are in register and the angled slots 35 urge the talon 39 along the horizontal slots 42, 43 into the first horizontal notches 37, so preventing vertical sliding movement of the second to sixth levers 28-32. This prevents the key cam 21 rotating in the absence of a key 12.

The clutch is shown in more detail in Figures 4a and 4b. As seen in those Figures, each key cam 21 includes an end face 50 carrying an annular wall 51 formed with tow axial slots 52 angularly spaced by 1800. The two axial slots 52 of the one wall 51 are aligned with the corresponding slots 52 of the other wall 51. A clutch member is formed by two generally cylindrical clutch sections 53a, 53b that are arranged end-to-end between the end faces 50, are loosely held together by a connecting rivet 59 and are a sliding fit in a central bore in the locking cam ii. Each clutch section 53a, 53b includes a respective pair of clutch dogs 54a, 54b and 55a, 55b. Each dog, 54a, 54b, 55a, 55b is formed on the outer cylindrical surface of the associated section 53a, 53b in the form of a radially projecting axially extending rib. Each pair of dogs 54a, 54b S 5 extends from one end of the associated clutch section 53a or 53b, is spaced by I 80E: and terminates outwardly of the centre of the clutch part 53 or 53b.

The dogs 54a, 54b, 55a and 55b engage in respective axial slots 52 in respective walls 51 of the associated key cams 21. When a key 12 is inserted into either of the key cams 21, the end of the key 12 engages the associated clutch section 53a or 53b and pushes the member 53 or 53b axially into the locking cam 11, with the dogs 54a, 54b, 55a, 55b being guided by their engagement with respective slots 52 until the dogs 54a, 54b or 55a, 55b engage with behind dogs 57 of the locking cam 11. At the same time, the other cam section 53a or 53b is pushed out engagement with the locking cam Ii * with the dogs 54a, 54b, 55a, 55b being guided in the slots of the associated key cam 21.

When an appropriate key 12 is inserted into the key slot 23, and rotated initially from the position shown in Figures 3a, 3b and 3c, the key cam 21 rotates and, as seen in Figures 5a, Sb and Sc, the V-shaped projections 44 on the first and seventh levers 27, 33 are urged out of the notches 25 in the key cam 21. This lifts the first and seventh levers 27, 33 so causing the angled slots 35 in these levers 27, 33 to move the talon 39 along the horizontal slots 42, 43 until the talon 39 is located in the central slots 36 of the second to sixth levers 28-32. The rotation of the key 12 also rotates the associated clutch section 53a or 53b and so rotates the locking cam 11.

Continued rotation of the key 12 engages the bits of the key 12 with respective second to sixth levers 28-32 to lift the levers 28-32 against the action of the springs 34 as seen in Figures 6a, 6b and 6c. With the correct key 12 in use, after about 140° of key rotation, all the lower ends 45 of the second to sixth levers 28-32 are correctly engaged with the associated key bits and these levers 28-32 are at the correct lift to enable the key cam 21 to rotate the locking cam 11 via the clutch 22.

Further rotation of the key 12 to 1800 from the rest position, as seen in Figures 7a, 7b and 7c engages the lug 24 on the key cam 2 I with the lower edges of the first and seventh levers 27, 33 so lifting these levers 27, 33 and moving the angled slots 35.

This, in turn, moves the talon 39 laterally in the horizontal slots 42, 43 until the talon * 6 engages in the second horizontal notches 38 of the second to sixth levers 28-32, which are in register in this position when the correct key 12 is used. Of course, if an incorrect key 12 is used, the second horizontal notches 38 will not be in alignment and the key 12 will not be able to be rotated.

Rotation of the key 12 beyond 1800 allows the levers 27-33 to drop under the action of the springs 34. The dropping of the first and seventh levers 28, 33 moves the talon 39 out of the second horizontal notches 38 into the central slots 36. As the key bits disengage the concave lower ends 45 of the second to sixth levers 28-33, these levers will drop and, when the first horizontal notches 37 are again in register, the angled * slots 35 will move the talon 39 back into engagement with these notches 37 and so regain the rest position.

The rotation of the locking cam 11 is used to operate any suitable kind of lock such as a mortice lock with a single bolt thrown or retracted by operation of the locking cam II or such as a multi-point lock system with a multiplicity of securing members operated and secured or merely secured by the locking cam 11. For example, the locking cam II may be used in a multi-point lock in which bolts or other lock points (such as hooks) are engaged or disengaged by operation of a handle with the locking cam 11 acting to secure the bolts or lock points in the "engaged" position.

Alternatively, the locking cam I l may be used to both move the bolts or other lock points and secure the bolts and other lock points. Another possibility is to use the action of the locking cam 11 to retract a latch bolt.

The other lock unit I Ob works in the same way so allowing the locking mechanism to be operated from either side of a door. The lock units I Oa, I Ob are connected using a high tensile steel screw 51 (Figure 1) extending between the mounting blocks 20 so making a very strong unit Of course, further rotations or part rotations of the key 12 can be utilised should secondary locking or unlocking actions be required by the associated lock.

As indicated above, an incorrect key 12 must be turned by about 1400 from the rest position before rotation is halted by the levers 27-33. In order to prevent such motion starting to move the locking cam 11 in an unlocking movement, lost motion may be provided between the key cam 21 and the locking cam 11 through, for example, the clutch 22.

There need not be two lock units IOa and lOb. One of the lock units IOa or lOb could be replaced by a thumb turn for use on the interior side of a door that allows manual rotation of the locking cam 11. The connection between a thumb turn and the locking cam 11 should ideally be permanent Such an arrangement is shown in Figures 8a and 8b. Parts common to these figures and the preceding Figures are given the same reference numerals and are not described in detail. In this arrangement, the second lock unit lOa is omitted together with the second clutch section 53b. The thumb turn indicated generally at 60 has a rotatable thumb-turn or wheel 61 connected to a central shaft 62 whose end is in fixed engagement with the locking cam Ii so that rotation of the thumb-turn or wheel 61 rotates the locking cam 11.

The first clutch section 53a is provided with a central passage 63 that extends into a projecting end 64 of the clutch section 53a, which, in turn, is received in a bore 64 at the end of the shaft 62. A first spring 66 acts between the end of the shaft passage 63 the end 64 of the clutch section 53a tending to urge the clutch section 53a out of engagement with the locking cam 11. A second spring 67 extends between the end of the central passage 63 of the clutch section 53a and an aligned key-receiving passage in the associated key cam 21.

Accordingly, when a key 12 is inserted into the key cam 21, the end of the key 12 engages the second spring 67 compressing the spring, which, in turn, pushes the dogs 54a, 54b of the cam section 53a into engagement with the locking cam 11 to transmit rotation of the key cam 21 to the locking cam 11. If the dogs 54a, 54b are not in register with the locking cam dogs 57, the second spring 67 will remain compressed until the key 12 rotates the cam section 53a and so rotates the dogs 54a, 54b until they * 8 register with the locking cam dogs 57 when engagement can take place. Removal of the key 12 allows the first spring 66 to urge the cam section 53a out of engagement with the locking cam 11.

As seen in Figures 8a and 8b, the clutch section passage 63 includes a steel ball 68 as an anti-drilling measure.

With most lever locks as fitted to external doors, such as mortise locks, the key bit may be inserted from either inside or outside the door. Since such locks have a common lock mechanism, the key bit needs to be symmetrical. This effectively * reduces the number of differs available with the number of levers used. The locking mechanism described above with reference to the Figures I to 7 of the drawings has, however, two locking units lOa, lob and each only accept a single key insertion direction and so asymmetric bits may be used to give more differs for the same number of fevers.

There could, of course, be more or less than seven levers. The movement of the talon 39 need not be as described above -any form of talon arrangement could be used.

For example, the talon 39, instead of floating, could be attached to a rocking arm to enter the horizontal slots 37, 38 in the second to sixth levers 28-32. These slots 37, 38 may be arcuate. The arm would engage with a cam form on the key cam so obviating the need for the horizontal slots 42, 43 and the angled slot 35. The location of the locking cam 11 and the clutch 22 at the centre of the mechanism reduces the likelihood of air and water reaching these parts. Anti-pick features may be applied to the second to sixth levers 28-32 as is common practice with lever locks. This may be done by slotting down the length of the talon 39 in contact with the second to sixth levers 28-32 and indenting these levers 28-32 along the edges of the vertical slots 36 near to the first and second horizontal slots 37, 38. This creates decoy "shallow" engagements of the talon 39 into the second to sixth levers 28-32, which makes picking more difficult.

Of course, the lock units lOa, lOb could be assembled in the reverse direction so that the front plate 14 and the front guide plate 40 are at the tear of the housing 13 and the * 9 rear wall plate 15 is at the front. This latter plate is not then removable and so gives additional security.

Additional security in the form of a hardened steel plate may be provided around the keyholel8 * 10

Claims

CLAIMS1. A locking mechanism comprising a cam member rotatable about an axis to operate a lock, a key rotatable to rotate the cam member arid a lever mechanism receiving the key and controlling rotation of the key.
2. A mechanism according to claim I wherein said lever mechanism is located on the axis of rotation of the cam member to one side of the cam member, a further mechanism being located on an opposite side of the cam member, the further mechanism being operable to rotate the cam member.
3. A mechanism according to claim I or claim 2 wherein a clutch mechanism is associated with the cam member and the lever mechanism, insertion of the key into the lever mechanism engaging the clutch mechanism to transmit rotation of the key to the cam member and removal of the key disengaging the clutch mechanism.
4. A mechanism according to claim 3 when dependant on claim 2 wherein the clutch mechanism is associated with the cam member and the further mechanism, operation of the further mechanism engaging the clutch mechanism to allow operation of the cam member.
5. A mechanism according to any one of claims I to 4 wherein the further mechanism comprises a thumb turn.
6. A mechanism according to any one of claims 1 to 5 wherein the further mechanism comprises a second lever mechanism for receiving a key, rotation of the key rotating the cam member.
7. A mechanism according to claim 6 when dependant on claim 3 or claim 4 wherein insertion of the key into the second lever mechanism engaging the * 11 clutch mechanism to transmit rotation of the key to the cam member and removal of the key disengaging the clutch mechanism.
8. A mechanism according to any one of claims Ito 7 wherein the or each lever mechanism comprises a key cam for receiving a key and a plurality of levers, rotation of the key rotating the key cam and moving the levers in accordance with bits on the key, the use of a correct key for the levers allowing rotation of the key sufficient to rotate the cam member.
9. A mechanism according to claim 8 wherein the or each lever mechanism * includes a talon, each lever including a formation co-operating with the talon, the talon allowing the levers to be moved by respective bits on rotation of a correct kcy to rotate the cam but preventing movement of at least one lever, and thus rotation of the key, when an incorrect key is used.
10. A mechanism according to claim 9 wherein, in an initial position of the key, the talon engages the levers to prevent the levers being moved form a rest position, initial rotation of the key moving the talon out of engagement with the levers and allowing the levers to move from the rest position on rotation of the key, continued rotation of the key re-engaging the talon with the levers to allow said continued rotation and rotation of the cam member, final rotation of the key disengaging the talon from the levers, allowing the levers to return to the rest position where the talon re-engages with the levers.
11. A mechanism according to claim 10 wherein the levers lie side-by-side in respective planes normal to the axis of rotation of the cam member and are constrained for movement by a key in respective radial directions relative to said axis.
12. A mechanism according to claim II wherein the talon extends through respective shaped apertures in the levers in a direction parallel to the axis of rotation of the cam member and is constrained to move in a direction transverse to the direction of movement of the levers. * 12
13. A mechanism according to claim 12 wherein the lever mechanism includes first and second opposed guide plates having respective elongate slots, the talon having first and second ends each engaging in a respective slot and being guided by said slots in movement in said transverse direction.
14. A mechanism according to claim 13 wherein the levers include at least one drive lever engaging the talon, the at least one drive lever being moved by the key cam on initial rotation of the key to move the talon along said slot out of engagement with the remaining levers and being moved by the key cam on * said continued movement of the key to move the talon along said slot to re-engage the talon with the remaining levers.
15. A mechanism according to claim 14 wherein the key cam includes a cam surface that engages the at least one drive lever on said initial rotation of the key cam by the key to move said at least one drive lever.
16. A mechanism according to claim 14 or claim 15 wherein the at least one drive lever includes a slot angled relative to the slots in the guide plates so that movement of the at least one drive lever relative to the guide plates moves the talon.
17. A mechanism according to any one of claims 12 to 16 wherein the shaped apertures include a first slot for receiving the talon in the rest position, an elongate slot for accommodating the talon as the associated levers are moved by the key and a second slot for receiving the talon on said re-engagement with the levers.
18. A mechanism according to any one of claims 10 to 17 wherein the levers are spring biased into said rest position, said spring bias moving the levers to disengage the talon from the levers, return the levers to the rest position and re-engage the talon with the levers on said final movement of the key. S 13
19. A locking mechanism substantially as hereinbefore described with reference to the accompanying drawings.
20. A lock or multi-point lock system comprising one or more bolts or other securing members movable between a retracted inoperative position and an extended operative position and secured in said extended operative position on rotation of a cam member, the cam member being rotated by a locking mechanism according to any one of claims I to 19.
21. A lock or multi-point lock system comprising one or more bolts or other * securing members movable between a retracted inoperative position and an extended operative position, at least one of said movements being controlled by movement of a cam member, the cam member being rotated by a locking mechanism according to any one of claims I to 19.