WO2015181540A1

WO2015181540A1 - Security screen

Info

Publication number: WO2015181540A1
Application number: PCT/GB2015/051538
Authority: WO
Inventors: Brian Malcolm Wilkins
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-05-27
Filing date: 2015-05-27
Publication date: 2015-12-03
Anticipated expiration: 2016-11-27
Also published as: TR201617199T1; CN106460450A; CN106460450B; MX2016015452A; GB201409386D0

Abstract

A security screen comprises a plurality of parallel metal rods (4) mounted within a frame which can be secured within a window or door opening of the building, the rods (4) are rotatable about their longitudinal axes, and each rod mounts a blade (2) extending from opposed sides of the rod and configured such that, when rotated to a closed position, the blades overlap with adjacent blades to form a continuous protective surface across the frame. Each blade is hollow and has a central longitudinal tubular formation along one face thereof configured to receive the rod.

Description

SECURITY SCREEN

Field of the Invention

[0001] This invention relates to a security screen for a window or door opening. Background to the Invention

[0002] In my earlier patent specifications WO0206620A, WO2008059265A and WO201 1080516A I disclosed and claimed security blinds of the type comprising a plurality of spaced-apart blades rotatable in the manner of a Venetian or a vertical slatted blind. In each case, the blind consists of a plurality of ex- truded blades, of metal or plastics material, each enclosing a steel rod mounted for rotation in a frame. The rods may also be slidably mounted to permit them to be slid to one or both sides (or ends) for access to the window or door.

[0003] In order to keep the profile of the blades as narrow as possible, to ensure that the appearance is more like a blind and less like window bars, the rod divides the internal space within the hollow blades into two parts. Where it is desired to confer on the blades some resistance to penetration by projectiles, for example to protect the occupants of the room from external gunfire, it has been proposed to insert into the cavities in the blades a ballistics-resisting material such as Kevlar^®. Because it is necessary to provide two separate pieces of ballistics-resisting material, it is difficult to ensure uniform protection across the width of the blade; there is a risk of a bullet penetrating between the material and the steel rod. In addition, the installation of the two pieces is more time- consuming than just one piece.

Summary of the Invention

[0004] According to the invention, there is provided a security screen comprising a plurality of parallel metal rods mounted within a frame which can be secured within a window or door opening of the building, the rods being rotatable about their longitudinal axes, each rod mounting a blade extending from opposed sides of the rod and configured such that, when rotated to a closed posi- tion, the blades overlap with adjacent blades to form a continuous protective surface across the frame, each blade being hollow and having a central longitudinal tubular formation along one face thereof configured to receive the rod.

[0005] Other features of the invention are set out in the claims.

Brief Description of the Drawings

[0006] In the drawings, which illustrate exemplary embodiments of the invention:

Figure 1 is a perspective view of portions of two blades in a blind according to a first embodiment, shown in the closed position;

Figure 2 is a cross section of one blade on line A-A in Figure 1 ; and Figure 3 is a cross section of one blade according to an alternative embodiment.

Detailed Description of the Illustrated Embodiment

[0007] Referring first to Figures 1 and 2, a security blind suitable for protecting the occupants of a room from the effects of external blast and small-arms fire consists of a series of rotatable blades 2 mounted on rotatable rods 4, for example of steel, extending across and secured in a frame (not shown) which is in turn mounted in a window or door opening so as to be between a door or window and the interior of the building of which they form a part. The rods 4 are shown in the Figures extending vertically, but it will be appreciated that they could be mounted to extend horizontally in the manner of a Venetian blind, for example. In either configuration, the rods are linked so as to rotate together, in other words rotation of one rotates the others, and a drive mechanism is provided for their selective rotation, for example using a chain or cord pulled manually by the user, or a motor drive. The drive mechanism will be over-ridden by, for example, impact on the open blade tips of a flexible sheet between the window glass and the security screen being distorted or pushed inwardly by the shock wave caused by an external blast, in the manner described in WO2008059265A and WO201 1080516A, for example.

[0008] Each blade 2 consists of an elongate extruded shell, of plastics mate- rial or metal, such as aluminium or an aluminium alloy, having moulded therein a lengthwise tubular formation 6, into which the rod 4 is inserted, from one end of the blade. The tubular formation 6 is discontinuous, i.e. the surrounding wall is provided with a lengthwise gap therein, to permit extrusion using a single mandrel. This simplifies manufacture while maximising strength. A continuous space 10 within the blade receives a ballistics-resisting insert 12, for example a carbon fibre reinforced laminate material or a Kevlar armour material, extending across the full interior space. When the blades overlap in the closed position as illustrated in Figure 1 , the full width of the window or door opening is protected by the ballistics-resisting material, so that any projectile striking the window will encounter the ballistics-resisting material and its kinetic energy will be sufficient- ly dissipated to ensure that it cannot enter the room and harm the occupants thereof. It will be appreciated that the ballistics-resisting material could alternatively be formed of metal, such as steel, or a ceramic material, and that multiple layers of material could be employed. It will also be appreciated that, while the rod conveniently has a circular cross-section, other profiles could be used, the tubular formation 6 in the extruded shell being shaped accordingly.

[0009] In the embodiment of Figure 3, the tubular formation 6 is external to the body of the shell, instead of internal, as in Figures 1 and 2. This permits the blade to adopt a more uniform internal profile. A steel insert 20 is formed with a curved portion 22 along each edge thereof, the curves extending in opposite directions, i.e. from opposite sides of the insert. The insert is fed into the shell from one end thereof, and may be flexed slightly to assist in holding it in place in the blade. The shape of the steel insert assists in providing additional protection at the overlap portions between the blades, where an obliquely-directed projectile could potentially force its way between the blades. The curved portion serves to engage such unusually-angled projectiles and dissipate their energy before they can enter the room.

[0010] Additionally, a second insert 24 can also be located within the blade to enhance the ballistics resistance. This may be formed of a different material, for example a ceramic or a composite fibre material such as that formed from ultra-high-molecular-weight polyethylene (Dyneema) fibres or from Kevlar. Various combinations of different material inserts can be used according to the perceived threat. Materials can be used to fill the blade that change their structure in response to the shock of ballistic impact, thereby increasing their resistance to penetration. Such materials are sold under the Registered Trade Mark "Ar- mourgel", for example.

[0011] The ballistics protection afforded by the security screen of the inven- tion is, as will be appreciated, only effective when the blades are in their closed positions - it will be expected that the users of the screen will have been alerted to the possibility of an external threat and will close the blind, preferably locking it closed by means of a locking bar extending across the internal face of the screen to prevent rotation of the blades. Protection will be further enhanced by the use of a ballistics-resisting material as the flexible sheet between the window or door and the screen. Thus, for example, the sheet might conveniently be formed of thicker polycarbonate sheet. It has been found that a thickness of 12mm is suitable to permit the triggering action discussed in my earlier patent specifications, while also absorbing significant energy from a projectile striking the sheet and so enhancing the effect of the screen.

Claims

1 . A security screen comprising a plurality of parallel metal rods mounted within a frame which can be secured within a window or door opening of the building, the rods being rotatable about their longitudinal axes, each rod mounting a blade extending from opposed sides of the rod and configured such that, when rotated to a closed position, the blades overlap with adjacent blades to form a continuous protective surface across the frame, each blade being hollow and having a central longitudinal tubular formation along one face thereof configured to receive the rod.

2. A security screen according to Claim 1 , wherein each blade is hollow, the hollow space containing a ballistics-resisting member.

3. A security screen according to Claim 2, wherein the blades, when in the closed position thereof, overlap sufficiently that the ballistics-resisting material within one blade overlaps the ballistics-resisting material in the next.

4. A security screen according to Claim 2 or 3, wherein the ballistics- resisting material is a laminated woven fibre material.

5. A security screen according to any preceding claim, wherein the tubular formation is internal to the blade.

6. A security screen according to any of Claims 1 to 4, wherein the tubular formation is substantially external to the blade.

7. A security screen according to any preceding claim, wherein the rod has a non-circular cross-section and the tubular formation corresponds internally thereto.