GB2375795A

GB2375795A - A double cylinder lock assembly

Info

Publication number: GB2375795A
Application number: GB0211873A
Authority: GB
Inventors: Donald Malcolm Fullard
Original assignee: FULLEX Ltd
Current assignee: FULLEX Ltd
Priority date: 2001-05-25
Filing date: 2002-05-23
Publication date: 2002-11-27
Anticipated expiration: 2022-05-23
Also published as: GB0211873D0; GB0112750D0; GB2375795B

Abstract

A double cylinder lock assembly 1 comprises two separate and spaced apart lock bodies 5,6 that are connected to one another by a link member 9 which is pivotally connected to the lock bodies 5,6 to provide for relative movement between the link member 9 and the lock bodies 5,6, but which relative movement is normally restricted by frangible interconnections 17,18 between the link member 9 and the lock bodies 5,6. The frangible interconnections are preferably provided by integral keys 17 formed on the link 9 and keyways 18 formed on the lock bodies 5,6. The frangible interconnections will break if an attempt is made to force the lock bodies apart. In addition to the frangible interconnections 17,18 the lock bodies 5,6 may each be provided with a lip 23 which normally restrains relative tilting of the lock bodies 5,6, but which shears away under a predetermined force.

Description

CYLINDER LOCKS This invention relates to cylinder locks and is concerned particularly with improving the resistance afforded by such locks against unauthorised entry through the doors or windows to which they are fitted for use.

More especially the invention is concerned with a cylinder lock of the kind, commonly known as a Euro profile cylinder, which is operable from opposite sides of a door or window and comprises two, separately actuable, aligned cylinders housed in a unitary body and each connected through a cam, located in a gap in the body between the cylinders, to a bolt for locking and releasing the bolt upon actuation of one or other of the cylinders by a key. Such a cylinder lock is hereinafter referred to as "of the kind described".

Hitherto the body has been a unitary component.

The gap in the body between the cylinders in which the cam is located weakens the body. Further weakening results from the usual provision of a fixing hole in the body adjacent the gap for a screw for fixing the cylinder lock in a door or window. The weakening of the body is such that unauthorised entry may possibly be gained through the door or window by the forcing of relative movement between the two parts of the body between which the gap is formed such as to cause the body to break in two at the gap. The forced movement may be produced, for example, by hammering an exposed end of the body in directions transverse to the longitudinal axis of the body, or by gripping an exposed end of the body by means of a suitable gripping tool, such as mole grips, and twisting the end about the longitudinal axis of the body. The reduced section of the body adjacent the gap fractures, usually through the fixing hole, under the forced movement. Once the body has been broken in two, the one part of

the body which has been subjected to the forced movement can be drawn out of its location in the door or window and access can be gained through the location to manipulate the bolt and release it for the door or window to be opened.

It is the aim of the present invention to provide a cylinder lock of the kind described which is able to offer greater resistance to unauthorised entry in the aforesaid manner through the door or window to which the cylinder is fitted for use.

According to the present invention there is provided a cylinder lock of the kind described the body of which comprises two separate body parts each housing a respective one of the cylinders and being connected in a spaced, aligned relationship, to define the gap therebetween for the cam, by means of a link which is pivotally attached to the body parts for relative movement between the link and body parts about parallel pivotal axes at opposite sides of the gap disposed transversely of the axis of alignment of the body parts, but which relative pivotal movement is normally restrained by frangible interconnections between the link and body parts.

Thus the two body parts are normally held in alignment by the link so that when the cylinder lock is fitted for use in a door or window it can be operated from either side of the door or window by actuation of the respective cylinder by a key. However, if force is applied to either body part, as for example in the manner described, in an attempt to break the body in two at the gap, the frangible interconnections between the link and body parts, or at least one of the body parts, will break and allow the relative pivotal movement between the link and at least one of the body parts. The relative pivotal movement prevents, or substantially reduces the likelihood of, the body parts being separated from the link under the applied force for removal from the door or window.

The frangible interconnections may be provided by interengagement of male and female or male and male formations at the link and body parts.

For example, interengaging keys and keyways may be provided, mating ribs or ribs, lips or comparable projections engaging with abutments or abutment surfaces.

In a preferred embodiment, a key and keyway interengagement provides a frangible interconnection between each end of the link and the respective body part extending parallel to the pivotal axes of the pivoted attachments of the link to the body parts. In this embodiment the keys are provided on the link and the keyways are in the body parts but the opposite arrangement may be provided.

In addition, or possibly alternatively, a lip, or like projection, and an abutment or abutment surface, extending transversely with respect to the pivotal axes may provide a frangible interconnection between each end of the link and the respective body part.

The keys and/or lips or the projections are designed to shear under force such as described applied to either body part.

The body parts and link may be made as castings, for example of brass.

The link may be made of a different material from the body parts.

The link may be pivoted to the body parts by means of screws, for example located in plain bore holes in the link and tightened into screw-threaded holes in the body parts. Other suitable pivot means may be used.

A fixing hole may be provided in the link to be engaged by a screw for fixing the cylinder lock in a door or window for use.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side view of a cylinder lock in accordance with the present invention, and Figure 2 is an exploded perspective view of the cylinder lock.

As shown in the drawings, the cylinder lock comprises a body 1, which houses two, separately key-actuable, aligned cylinders 2,3 connected in known manner by key barrels, not shown, to a cam 4.

The body 1 comprises two separate body parts 5,6 which are similar, each being elongated and of a generally key-hole shape in cross-section having a cylindrical portion 7 and a stem portion 8. The cylinders 2,3 are respectively housed in the cylindrical portions 7 of the two body parts 5,6. A link 9 connects the two body parts 5,6 in spaced axial alignment of the cylindrical and stem portions 7,8. The spaced body parts 5,6 leave a gap 10 between them in which the cam 4 is located on the key barrels.

The body parts 5,6 and the link 9 are made as castings in brass.

Opposite ends 11 of the link are received into square-cut recesses 12 formed in adjacent ends of the stem portions 8 of the body parts, such that the link is contained within the depth of the stem portions. Each of the opposite ends 11 is semi-cylindrically rounded coaxially with a counter-sunk plain bore hole 13 extending through the end. The holes 13

in the two ends 11 are parallel and a screw 15 freely engaged in each hole 13 screws into a screw-threaded hole 16 in the stem portion 8 of the respective body part, the head of the screw being received into the countersinking of the hole. The screws 15 provide pivotal connections between the ends of the link and the body parts. However, relative pivotal movement between the link and body parts is normally restrained by frangible interconnections between those components.

The frangible interconnections are provided at the opposite ends 11 of the link 9 and the recesses 12 of the stem portions 8 of the body parts. Each of the opposite ends 11 is formed centrally with an integral key 17, extending parallel to the axes of the plain bore holes 13, which engages in a complementary keyway 18 formed centrally in the adjacent face 19 of the recess 12. The recess face 19 is tangential to the semi-cylindrical shape of the end 11.

In addition, each of the opposite ends 11 has an inset surface 20 adjacent and directed towards the cylindrical portion 7 of the respective body part 5,6. The provision of the inset surface 20 presents a step on the link directed towards the adjacent plain bore hole 13, normal to a central longitudinal plane through the link 9 containing the axes of the two plain bore holes 13. Each step 21 is positioned to be inset a short distance from the outer edge of the adjacent overhanging face 22 of the recess 12.

At the said outer edge of the overhanging face 22 a lip 23 is defined across the end of the stem portion 8 by the formation of a groove 24 in the end of the stem portion parallel to the outer edge. The lip 23 normally overlaps the link at the step 21, thereby spacing the adjacent inset surface 20 of the link from the overhanging face 22 of the recess 12 in the respective body part.

By virtue of the engagement of the keys 17 of the link in the keyways 18 of the body parts 5,6, relative pivotal movement of the link and body parts about the screws 15 is restrained. Furthermore, the overlapping of the link by the lips 23 restrains relative tilting movement between the body parts and the link.

This is the condition in which the cylinder lock is fitted for use in a door or window. A central transverse fixing hole 25 is formed in the link for a screw for fixing the cylinder lock in place in the door or window.

The cylinder lock provides substantial resistance to unauthorised opening of the door or window to which it is fitted for use, under application of force on either body part such as would cause relative movement between the two parts of the body of a conventional cylinder lock of the kind described intended to break the cylinder lock at the gap. Thus force aimed at producing relative lateral movement between the body parts 5,6, to break the body in two would cause at least one of the keysl7 of the link 9 to shear away well before sufficient force could be applied to break the link itself. Relative pivotal movement could then occur between the body parts and link, while the components remain connected, rendering such force ineffective. If force were to be applied aimed at producing relative tilting movement between the body parts to break the body in two in that way, the lip 23 of at least one of the body parts would shear away, allowing relative tilting movement between the body parts and link which would thereby render that force ineffective as well.

Although attempts may have been made to break the lock when it is in use and resultant breaking away of the keys 17 and lips 23 may have occurred, the lock may still be released subsequently by key actuation of one or other of the cylinders 2,3. It would then need to be replaced.

Claims

Claims 1. A cylinder lock of the kind described the body of which comprises two separate body parts each housing a respective one of the cylinders and being connected in a spaced, aligned relationship, to define the gap therebetween for the cam, by means of a link which is pivotally attached to the body parts for relative movement between the link and body parts about parallel pivotal axes at apposite sides of the gap disposed transversely of the axis of alignment of the body parts, but which relative pivotal movement is normally restrained by frangible interconnections between the link and body parts.
2. A cylinder lock according to claim 1 wherein the frangible interconnections are provided by interengagement of male and female formations at the link and body parts.
3. A cylinder lock according to claim 2 wherein the male and female formations comprise interengaging keys and keyways.
4. A cylinder lock according to claim 3 wherein the interengaging keys and keyways provide frangible interconnections between each end of the link and the respective body part extending parallel to the pivotal axes of the pivoted attachments of the link to the body parts.
5. A cylinder lock according to claim 4 wherein the keys are provided on the link and the keyways are in the body parts.
6. A cylinder lock according to claim 1 wherein the frangible interconnections are provided by interengagement of male formations at the link and body parts.

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7. A cylinder lock according to claim 6 wherein the male formations arc mating ribs at the link and body parts.
8. A cylinder lock according to claim 1 wherein the frangible interconnections are provided by projections engaging with abutments or abutment surfaces.
9. A cylinder lock according to claim 8 wherein the projections and the abutments or abutment surfaces extend transversely with respect to the pivotal axes to provide the frangible interconnection between each end of the link and the respective body part.
10. A cylinder lock according to any proceeding claim wherein the body parts and link are made as castings.
11. A cylinder lock according to any proceeding claim wherein the link is pivoted to the body parts by means of screws located in plain bore holes in the link and tightened into screw-threaded holes in the body parts.
12. A cylinder lock according to any proceeding claim wherein a fixing hole is provided in the link to be engaged by a screw for fixing the lock in a door or window for use.
13. A cylinder lock according to any proceeding claim wherein the two body parts are of similar shape each being elongated and of a generally key-hole shape in cross-section having a cylindrical portion and a stem portion, the cylindered portion housing the respective cylinder and the stem portion being pivotally connected to a respective end of the link.

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14. A cylinder lock according to claim 13 wherein the opposite ends of the link are received into recesses in adjacent ends of the stem portions and contained within the depth of the stem portions from the cylindrical portions.
15. A cylinder lock according to claim 5 and claim 14 wherein each of the opposite ends of the link is semi-cylindrically rounded coaxially with the respective pivotal axis of the end to the body part and has one said key centrally positioned on the semi-cylindrical rounding of the end and extending parallel to said pivotal axis, and the recess in the adjacent end of the stem portion of the body part in which the end of the link is received has one said keyway centrally positioned which is complementary to and engaged by said key.
16. A cylinder lock according to claim 15 wherein each of the opposite ends of the link has an inset face adjacent and directed towards the cylindrical portion of the respective part whereby a step is presented on the link directed to the respective pivotal axis and normal to a central longitudinal plane through the link containing the pivotal axes at the ends of the link to the body parts, and the recess in the stem portion of the respective body part has at an outer edge of a face of the recess overhanging said end of the link a lip is defined across the stem portion which normally overlaps the link at said step, spaces the inset face of the link from said overhanging face of the recess and restrains tilting movement between the body part and link.
17. A cylinder lock substantially as described herein with reference to the accompanying drawings.