GB2413592A

GB2413592A - Cylinder lock with protection means

Info

Publication number: GB2413592A
Application number: GB0508387A
Authority: GB
Inventors: Robert Wilkinson
Original assignee: SECURE CAST Ltd
Current assignee: SECURE CAST Ltd
Priority date: 2004-04-29
Filing date: 2005-04-26
Publication date: 2005-11-02
Anticipated expiration: 2025-04-26
Also published as: GB2413592B; GB0508387D0

Abstract

A cylinder lock guard 1 suitable for a closure has a bore 4 in which a cylinder lock mechanism 12 is to be located. The cylinder lock guard is provided with at least one lateral attachment 14 means to attach to the cylinder lock mechanism and at least one lateral attachment 15, 16 to a closure. At least one edge of the front face of the guard is bevelled 3, preferably the entire edge. The bore maybe keyhole shaped. The attachment means may be screws. The cylinder guard may be provided with anti drill means. Further claimed is the above assembly in combination with a back plate 11.

Description

The invention relates to cylinder locks, for example those known as

Eurolocks.

Generally, a lock mechanism of a Eurolock has a substantially uniform keyhole shaped cross-section, although other cross-sections such as oval, elliptical or circular are possible. The lock mechanism is held in the bore of a cylinder guard along its longitudinal axis i.e. perpendicular to the main plane of the closure. Such locks are often surface-fitted or internally fitted in closures such as doors and windows, with or without a backing plate. Unfortunately such locks are vulnerable to attack by burglars, by hammering the cylinder guard and/or twisting it to snap it in half, thus exposing the lock mechanism which can be opened with a screwdriver.

An object of this invention is to provide an improved cylinder guard which is more resistant to attack.

According to one aspect of the present invention there is provided a cylinder guard suitable for a closure in which the cylinder guard has an internal bore within which a cylinder lock mechanism is to be located wherein the cylinder guard is provided with at least one means for lateral attachment to a cylinder lock mechanism and at least one means for lateral attachment to a closure, and wherein at least one edge of the front face of the cylinder guard is bevelled.

Lateral' is with relation to the longitudinal axis of the cylinder guard. 'Front face' refers to the position of the guard relative to the closure, i.e. the outer face which would be exposed to potential attack. Where reference is made to 'top' or 'bottom' or lateral', these relate to the positions when the cylinder guard is fitted on a closure.

Preferably the means for lateral attachment in each case is a screw thread and complementary screw; alternatively, the attachment means may be a bore and complementary rivet. Particularly for the means for lateral attachment of the cylinder guard to a closure, it is preferable if the entry edge to each screw thread is bevelled to aid location of the screw into the screw thread.

Preferably the or each means for lateral attachment of the cylinder guard to a cylinder lock mechanism is substantially perpendicular to the longitudinal axis of the cylinder guard i.e. substantially in the main plane of the closure (e.g. a door).

Preferably there is a single means for lateral attachment of the cylinder guard to a cylinder lock mechanism and this is preferably located so that it passes through the cylinder guard at a position where there is a significant bulk of material. Where the cylinder guard has a keyhole shaped bore, then this position will often be nearer the bottom of the cylinder guard than the top.

Similarly, preferably the or each means for lateral attachment of the cylinder guard to a closure is substantially perpendicular to the longitudinal axis of the cylinder guard i.e. substantially in the main plane of the closure (e.g. a door). Preferably there are two such attachment means, one near the top of the cylinder guard and the other near the bottom of the cylinder guard.

The cylinder lock mechanism is usually of complementary configuration to the bore and the bore is preferably keyhole shaped.

According to another aspect of the present invention a cylinder lock assembly suitable for a closure comprises in combination a back plate and a cylinder guard, the cylinder guard having an internal bore within which a cylinder lock mechanism is to be located wherein the cylinder guard is provided with at least one means for lateral attachment to a cylinder lock mechanism and at least one means for lateral attachment to a closure, and wherein at least one edge of the front face of the cylinder guard is bevelled.

The back plate and cylinder guard may be integral or as two separate components, attached e.g. by means of screws or rivets. The cylinder guard of the present invention may be used in combination with an existing back plate on a closure. Preferably the back plate and/or cylinder guard is provided with at least one anti-drill means e.g. it could be formed entirely from a material hardened so that it is greater in hardness than a standard drill bit such as a hardness of around 55 - 65 HRC. An example of such a material would be cast steel, heat treated to give a hard skin so that the component does not become brittle. Alternatively, anti-drill means may be cast in, moulded or attached to the back plate/or cylinder guard e.g. in the form of hardened needle rollers and/or ball bearings pressed into castings of alloy. The assembled castings may then be inserted into the back plate/or cylinder guard tooling before the alloy is injected to form the finished component. The anti-drill means are preferably positioned at least at the positions where the cylinder guard is laterally attached to the closure and where the back plate is attached to the closure. In an embodiment where the cylinder guard is attached to the back plate or closure perpendicularly to the closure, e.g. by means of screws or rivets, anti-drill means would preferably be provided in the cylinder guard in those areas of attachment.

An embodiment of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a perspective front view of a cylinder guard; Figure 2 is a schematic front view, partially cut away to show the cylinder guard of Figure I fitted in a closure; Figure 3 is a perspective front view of the cylinder guard of Figure 1, but only partially constructed; Figure 4 is a perspective front view of an anti-drill means in the form of needle rollers held in a casting, for insertion into a back plate; Figure 5 is a perspective front view of an anti-drill means in the form of ball bearings held in a casting, for insertion into a back plate; Referring to Figure 1, a 'stand alone' cylinder guard 1 e.g. of hardened cast steel has a front face 2 with a bevelled edge 3 extending completely around it. The guard 1 defines a key-hole shaped bore 4, two cylindrical bores 5,6 for fixing back plate 11 to the cylinder guard 1, the bores 5,6 being above and below bore 4, a threaded cylindrical bore 7 laterally of the guard 1, and two threaded cylindrical bores 8,9 adjacent top and bottom of the guard 1 and laterally thereto.

Referring to Figure 3, this shows guard 1 in partial construction with an anti-drill plate incorporating ball bearings 11. Other numbered components correspond to those in Figure 1.

Referring to Figure 2, this shows guard l attached behind a back plate 11 which is cut away to show the guard 1. The guard 1 contains a lock mechanism 12 attached within guard 1 by means of a screw l 4 through bore 7 (See Figure I) in a lateral direction i.e. in the plane of the closure 13. The guard 1 is laterally attached to the closure 13 (partially shown) e.g. a door, by means of screws l 5,16 through threaded bores 8,9 respectively (see Figure 1). Screws 17 and 18 (not shown) would go through bores 5 and 6 to attach the guard l to the back plate 1 1. A hole 19 is provided for insertion of a handle (not shown). In the region where the back plate 11 is attached to the closure 13, an anti-drill means are provided shown as 20. This is of the type shown in Figure 4 i.e. in the form of needle rollers held in a casting. Alternatively, the anti-drill means of Figure 5 in the form of ball bearings held in a casting could be substituted for component 20.

In use, the cylinder guard 1 lies behind the back plate 1 1 and is thus protected from attack from the front. Also, the bevelled edge 3 deflects any hammer blows, should the back plate l l be removed. Because when the door is closed within a door frame(not shown), the screw fastenings 14, 15 and 16 are hidden and thus protected, this makes the assembly more resistant to attack. Furthermore, the lateral attachments 14,15 and 16 make the guard [resistant to attack by pulling, twisting and hammering.

Anti-drill means 20 protects the back plate 11 from drill or screwdriver attack; anti drill plate 10 incorporating ball bearings l l similarly protects the cylinder guard 1.

Usually an anti-drill means acts by jamming or snapping the drill bit being used to attack it.

It will be appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable combination.

Claims

Claims: 1. A cylinder guard suitable for a closure, the cylinder guard

having an internal bore within which a cylinder lock mechanism is to be located wherein the cylinder guard is provided with at least one means for lateral attachment to a cylinder lock mechanism and at least one means for lateral attachment to a closure, and wherein at least one edge of the front face of the cylinder guard is bevelled.
2. A cylinder guard according to claim 1 wherein the internal bore has a substantially uniform keyhole shaped cross-section.
3. A cylinder guard according to claim 1 or 2 wherein substantially the entire edge of the front face of the cylinder guard is bevelled.
4. A cylinder guard according to any preceding claim wherein the means for lateral attachment to a cylinder lock mechanism comprises a screw thread and complementary screw.
5. A cylinder guard according to any preceding claim wherein the means for lateral attachment to a closure comprises a screw thread and complementary screw.
6. A cylinder guard according to claim 4 or 5 wherein a bevelled surface is provided adjacent the screw thread to assist location of the screw into the thread.
7. A cylinder guard according to any preceding claim wherein the means for lateral attachment to a cylinder lock mechanism is substantially perpendicular to the longitudinal axis of the cylinder guard.
8. A cylinder guard according to any preceding claim wherein the means for lateral attachment to a closure is substantially perpendicular to the longitudinal axis of the cylinder guard.
9. A cylinder guard according to any preceding claim wherein the cylinder guard is provided with anti-drill means.
10. A cylinder guard according to claim I and substantially as herein described with reference to any one Figures 1 to 5.
11. A cylinder lock assembly suitable for a closure comprises in combination a back-plate and a cylinder guard, the cylinder guard having an internal bore within which a cylinder lock mechanism is to be located wherein the cylinder guard is provided with at least one means for lateral attachment to a cylinder lock mechanism and at least one means for lateral attachment to a closure, and wherein at least one edge of the front face of the cylinder guard is bevelled.
12. A cylinder lock assembly according to claim 11 and having the feature of any one of claims 1 to 10.
13. A cylinder lock assembly according to claim I I or 12 wherein the back-plate and cylinder guard comprise separate components.
14. A cylinder lock assembly according to claim 11, 12 or 13 wherein the back- plate includes at least one anti-drill means.
15. A cylinder lock assembly according to claim I I and substantially as herein described with reference to any one of Figures I to 5.