GB2202892A

GB2202892A - Double cylinder lock assembly

Info

Publication number: GB2202892A
Application number: GB08707631A
Authority: GB
Inventors: David Brian Legge
Original assignee: J Legge and Co Ltd
Current assignee: J Legge and Co Ltd
Priority date: 1987-03-31
Filing date: 1987-03-31
Publication date: 1988-10-05
Also published as: GB8707631D0

Abstract

The assembly has a bolt drive means 40 comprising first and second latch members 51, 52 driven by respective first and second cylinders 21, 22, first and second resilient biasing means 59, 61 to bias respective latch members 51, 52 towards driving engagement with a bolt drive member 40, the relative strength of the biasing means 59, 61 being such that when a key 39 is received in a key receiving slot 37 of second cylinder 22 the resilient bias of second biasing means 61 is stronger than the bias provided by first biasing means 59 but when the key 39 is not received in slot 37 the bias of biasing means 61 is weaker than that of biasing means 59. As shown, biasing means 59 comprises two coil compression springs and biasing means 61 comprises a single coil compression spring and when key 39 is inserted in slot 37 its tip engages the end of spring 61 to move it to press latch member 52 against bolt drive member 41 and a tongue 54 on latch member 52 will engage a tongue 53 on latch member 51 and displace it out of aperture 44 in drive member 41. It is envisaged that with cylinder 22 on the inside and cylinder 21 on the outside of the door - if key 38 is left in cylinder 21 it will always be possible to open the door by using key 39 on the outside to override the effect of key 38. <IMAGE>

Description

Title: Cylinder Assembly.

Description of Invention This invention relates to a cylinder assembly in or for a key operated lock capable of operation from either end of the kind, hereinafter referred to as the kind specified, comprising a body, a pair of rotatable cylinders mounted therein in end to end relationship, each cylinder having a plurality of locking tumblers movable in and relative to, the cylinder between locking positions in which they engage partly in the cylinder and partly in the body to hold the cylinder against rotation relative to the body and releasing positions in which they are disposed wholly in the cylinder, biasing meons for urging the locking tumblers into their locking positions, a key receiving slot in the cylinder in which a key can be inserted to displace the locking tumblers to their releasing position preparatory to rotation of the cylinder, the key receiving slots being disposed so as to receive a key inserted from either end of the cylinder assembly, and a bolt drive means movable with a cylinder on rotation thereof to drive, in use, a bolt between locking and releasing positions.

Hitherto, if a first key has been inserted in one end of a lock embodying a cylinder assembly of the kind specified it has been impossible to operate the lock with a second key inserted into the other end, unless the cylinder containing the first key happens to be disposed in the key receiving position and so that the second key con displace the first key in direction axially outwardly of the key receiving slot. Consequently, if, for example, a user closes a door to which the lock is fitted and accidentally leaves a key in the lock on the inside of the door the lock cannot be operated from the outside and hence the door cannot be opened.

An object of the invention is to provide a cylinder assembly of the kind specified whereby this problem is overcome.

According to the present invention we provide a cylinder assembly of the kind specified wherein the bolt drive means comprises a first latch -member rotatable by a first of said cylinders, first resilient biasing means resiliently to bias the first latch member towards driving engagement with a bolt drive member, a second latch member rotatable by the second of said cylinders, second resilient biasing means resiliently to bias the second latch member towards driving engagement with the bolt drive member, the first resilient biasing means being operative to move the first latch member into driving engagement with the bolt drive member and to displace the second latch member out of driving engagement with the bolt drive member when a key is not inserted in the key receiving slot of the second cylinder and the second resilient biasing means being operative to move the second latch member into driving engagement with the bolt drive member and displace the first latch member out of driving engagement with the bolt drive member only when a key is inserted in the key receiving slot of the second cylinder.

The relative strengths of the first and second resilient biasing means is such that when no key is received in the key receiving slot of the second cylinder the first resilient biasing means is sufficiently strong to overcome the bias of the second resilient biasing means so that the first latch member can be moved into driving engagement, and the second latch member out of driving engagement, with the bolt drive member. However, when a key is engaged in the key receiving slot of the second cylinder the key acts on the second resilient biasing means to increase its strength so thot it is stronger than the second resilient biasing means so that the second latch member is moved into driving engagement, and the first latch member out of driving engagement, with the bolt drive member.The strength of the first resilient biasing means is not affected by the presence or absence of a key in the key receiving slot of the first cylinder.

The first resilient biasing means may comprise a coil compression spring means acting between the first cylinder and the first latch member and positioned so as not to be engaged by a key received in the key receiving slot of the first cylinder.

The second resilient biasing means may comprise compression spring means acting between the second cylinder and the second latch member and positioned so that one end of the compression spring means is engaged by a key received in the key receiving slot of the second cylinder so as to further compress the spring against the second latch member.

The first and second latch member may be provided with.a tongue for engagement with an abutment means of, which may comprise a co-operating opening formed in, the bolt drive member.

The opening in the bolt drive member may be disposed eccentrically of the axis of rotation of the bolt drive member so that the tongue on the latch members are moved into driving engagement with the bolt drive member in only one angular position.

The latch members may be of generally plate like configuration having oppositely disposed planar surfaces and being received in corresponding shaped slots formed in the end of their respective cylinders.

The first latch member moy be provided with a pair of spaced recesses in the edge thereof which faces outwardly of the cylinder assembly within which the one ends of a pair of coil compression springs may be received, the other ends of the springs being received in recesses formed in the first cylinder at positions spaced away from the path of movement of a key as it is engaged in the key receiving slot of the first clinder.

The second latch member may be provided with a recess in the edge thereof facing outwardly of the cylinder assembly within which one end of a compression spring is received, the other end of the compression spring being received within the second cylinder in the path of movement of the end of a key as it is engaged in said key receiving slot of the second cylinder.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings wherein, FIGURE I is a cross-sectional view through a lock incorporating a cylinder assembly embodying the present invention, FIGURE 2 is a cross-sectional view, to an enlarged scale, on the line 2-2 of Figure I, and FIGURE 3 is a exploded view on the arrow A of Figure 2.

Referring to the drawings a mortise lock 10 has a bolt 11 which is movable in conventional manner by a cylinder assembly 12 in co-operation with a tumbler 13. The mortise lock 10 is also provided with a handle operated latch 14 of conventional form. The present invention is particularly concerned with the cylinder assembly 12 which is best shown in Figures 2 and 3 to which reference is now directed.

The cylinder assembly 12 comprises a body 20 within which are rotatably mounted first and second cylinders 21, 22 respectively. The cylinders 21, 22 are received in end to end relationship in a generally cylindrical bore 23 provided in the body 20.

Each cylinder 21, 22 has five locking tumblers 24, 25 which are movable in and relative to radial bores 26, 27 of the cylinders between locking and releasing positions. In the locking positions they engage partly in the cylinder bores 26, 27 and partly in radial bores 28, 29 formed in the body. In this position the tumblers 26, 27 hold the cylinders 21, 22 against rotation relative to the body 20. Coil compression springs 31 act between bungs 32, 33 and top pins 34, 35 normally resiliently to bias the locking tumblers 26, 27 into their locking positions. Each cylinder 21, 22 is provided with a key receiving slot 36, 37 into which a key 38, 39 can be inserted to displace the locking tumblers to their releasing positions, in which they are disposed wholly within the cylinder, preparatory to rotation of the respective cylinder 21, 22 by the respective key 38, 39.

A bolt drive means 40 is movable with the cylinders 21, 22 on rotation of a cylinder to drive the bolt 11 between locking and releasing positions.

The bolt drive means 40 comprises a bolt drive member 41 mounted for rotation within the body 20 and having a nose 42 for driving engagement with a cut out 43 of the bolt 11 and tumbler releasing engagement with the tumbler 13 in conventionol manner.

The bolt drive member 41 is provided with an eccentric rectangular aperture 44 extending therethrough for driving engagement with a first latch member 51 or a second latch member 52 associated with the first or second cylinders 21, 22 respectively. In this embodiment the first and second latch members are identical and comprise generally rectangular metal plates having a projecting tongue part 53, 54 on the edge thereof which faces inwardly of the cylinder assembly and a central recess 55, 56 and a pair of spaced recesses 57, 58 on the opposite edge which faces outwardly of the cylinder assembly.

The latch members 51, 52 are received within correspondingly shaped slots 63, 64 formed in their associated cylinders 21, 22 for axial sliding movement relative thereto but so as to be rotated with their associated cylinder when the cylinder is rotated by its associated key 38, 39.

The first latch member 51 has the one end of a pair of coil compression springs 59 received in the recesses 57 whilst the other ends of the springs 59 are received in recesses 60 formed in the first cylinder 21. The springs 59 comprise first resilient biasing means which are resiliently to bias the first latch member 51 towards the bolt drive member 41 so that the tongue 53 is caused to drivingly engage with the aperture 44, when the cylinder is rotated to align the tongue 53 and opening 44.

The second latch member 52 has one end of a single coil compression spring 61 received within the recess 56 whilst the other end of the spring 61 is received within the slot 64, formed in the second cylinder 22, in the path of movement of the end of the key 39 receivable in the key receiving slot 37 of the cylinder 22. The spring 61 is of such strength that its resilient bias when the key is received within the slot 37 is stronger than the resilient bias provided by the pair of compression springs 59 engaged with the first latch member 51 but weaker than the resilient bias of the springs 59 when the key 39 is not received in the slot 37.

When the key 38 is inserted in the key receiving slot 36 in the first cylinder 21 has no effect upon the coil compression springs 59. If no key is inserted in the key receiving slot 37 of the second cylinder 22 then when the key 38 rotates the cylinder 21 the springs 59 will urge the latch member 51 towards the bolt drive member 41 until the tongue 53 is aligned with the aperture 44 where upon the tongue 53 will engage the tongue 54 of the latch member 52 and displace the latch member 52 to the left in Figure 3 out of driving engagement with the bolt drive member 41 whilst the tongue 53 and aperture 44 will move into driving engagement so that continued rotation of the cylinder 21 will rotate the bolt drive member 41 to drive the bolt.

Conversely, irrespective of the presence or absence of the key 38 in the key receiving slot 36 of the cylinder 21, when the key 39 is inserted in the key receiving slot 37 of the cylinder 22 then its leading tip will engage the end of the coil compression spring 61 and move its abutment position to the right in Figure 3. Thus the spring 61 will press the latch member 52 against the bolt drive member 41 until the tongue 54 becomes aligned with the aperture 44 whereupon the tongue 54 will enter the aperture 44 and, because the spring 51 (when compressed because of the presence of the key 39) has a bias greater than the bias provided by the spring 59, the tongue 54 will engage the tongue 53 of the latch member 51 and displace it out of the aperture 44 so that the tongue 54 is moved into driving engagement with the aperture 44.Continued rotation of the second cylinder 22 by the key 39 will thus rotate the bolt drive member 41.

If a key 38 is left in the key receiving slot 36 of the cylinder 21 then this will have no effect upon the above described action of the key 39 since the key 38 will not affect the bias provided by the springs 59. Thus, whether or not a key 38 is engaged in the key receiving slot 36 of the cylinder 31 insertion of a key 39 into the key receiving slot 37 of the cylinder 22 will permit the cylinder assembly and hence the lock 10, to be operated. When the key 39 is not engaged in the key receiving slot 37 then the position of abutment of the spring 61 at the cylinder end is displaced to the left in Figure 3 and hence the strength of the resilient biasing means provided by the spring 61 is less than that provided by the springs 59 so that the springs 59 can bias the latch member 51 sufficiently strongly to displace the latch member 52 out of the aperture 44.

In the present example the cylinder assembly 12 is provided within the lock 10 so that the second cylinder 22 is positioned on the outside of the door and the first cylinder 21 on the inside. In this case, if a key 38 is inadvertently left in the'lock assembly on the inside of the door it will always be possible to open the door by using the key 39 on the outside to override the effect of the key 38. Of course, if desired, the cylinder assembly can be positioned in the opposite orientation so that it is the key on the inside which is provided by the key 39 and this will always permit the door to be opened even if the key has been inadvertently left on the outside.

The features disclosed in the foregoing description, or the accompanying drawing, expressed in their specific forms or in terms of a means for performing the disclosed function, or a metal or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS.

I. A cylinder assembly of the kind specified wherein the bolt drive means comprises a first latch member rotatable by a first of said cylinders, first resilient biasing means resiliently to bias the first latch member towards driving engagement with a bolt drive member, a second latch member rotatable by the second of said cylinders, second resilient biasing means resiliently to bias the second latch member towards driving engagement with the bolt drive member, the first resilient biasing means being operative to move the first latch member into driving engagement with the bolt drive member and to displace the second latch member out of driving engagement with the bolt drive member when a key is not inserted in the key receiving slot of the second cylinder and the second resilient biasing means being operative to move the second latch member into driving engagement with the bolt drive member and displace the first latch member out of driving engagement with the bolt drive member only when a key is inserted in the key receiving slot of the second cylinder.
2. A cylinder assembly according to claim I wherein the relative strengths of the first and second resilient biasing means is such that when no key is received in the key receiving slot of the second cylinder the first resilient biasing means is sufficiently strong to overcome the bias of the second resilient biasing means so that the first latch member can be moved into driving engagement, and the second latch member out of driving engagement, with the bolt drive member.
3. A cylinder assembly according to claim 2 wherein the assembly is adapted so that when, in use, a key is engaged in the key receiving slot of the second cylinder the key acts on the second resilient biasing means to increase its strength so that it is stronger than the second resilient biasing means so that the second latch member is moved into driving engagement, and the first latch member out of driving engagement, with the bolt drive member.
4. A cylinder assembly according to claim 3 wherein the strength of the first resilient biasing means is not affected by the presence or absence of a key in the key receiving slot of the first cylinder.
5. A cylinder assembly according to any one of the preceding claims wherein the first resilient biasing means comprises a compression spring means acting between the first cylinder and the first latch member and positioned so as not to be engaged by a key received in the key receiving slot of the first cylinder.
6. A cylinder assembly according to any one of the preceding claims the second resilient biasing means comprises a compression spring means acting between the second cylinder and the second latch member and positioned so that one end of the compression spring means is engageable by a key received in the key receiving slot of the second cylinder so as to further compress the spring against the second latch member.
7. A cylinder assembly according to any one of the preceding claims wherein the first and second latch member is provided with a tongue for engagement with an abutment of the bolt drive member.
8. A cylinder assembly according to claim 7 wherein the abutment means comprises a co-operating opening formed in the bolt drive member.
9. A cylinder assembly according to claim 7 or claim 8 wherein the abutment means of the bolt drive member is disposed eccentrically of the axis of rotation of the bolt drive member so that the tongue on the latch members is moved into driving engagement with the bolt drive member in only one angular position.
10. A cylinder assembly according to any one of the preceding claims wherein the latch members are of generally plate like configuration having oppositely disposed planar surfaces and are received in correspondingly shaped slots formed in the end of their respective cylinders.
II. A cylinder assembly according to any one of the preceding claims wherein the first latch member is provided with a pair of spaced recesses in the edge thereof which faces outwardly of the cylinder assembly within which the one ends of a pair of coil compression springs are received, the other ends of the springs being received in recesses formed in the first cylinder at positions spaced away from the path of movement of a key as it is engaged in the key receiving slot of the first clinder.
12. A cylinder assembly according to any one of the preceding claims wherein the second latch member is provided with a recess in the edge thereof facing outwardly of the cylinder assembly within which one end of a compression spring is received, the other end of the compression spring being received within the second cylinder in the path of movement of the end of a key as it is engaged in said key receiving slot of the second cylinder.
13. A cylinder assembly substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
14. Any novel feature or novel combination of features described herein or shown in the accompanying drawings.