GB2224533A

GB2224533A - Window security screen

Info

Publication number: GB2224533A
Application number: GB8825148A
Authority: GB
Inventors: David Wilfred Johnson; Carl John Cantello
Original assignee: JOHNSON BROS
Current assignee: JOHNSON BROS
Priority date: 1988-10-27
Filing date: 1988-10-27
Publication date: 1990-05-09
Anticipated expiration: 2008-10-27
Also published as: GB8825148D0; GB2224533B

Abstract

A security screen for a window is formed from inner and outer rigid frames (2, 3) between which a polycarbonate panel (1) is retained. The inner frame (2) is adapted to be secured around a window and the outer frame (3) is secured to the inner frame (2) by way of releasable fixing bolts (10) which extend through aligned holes in each frame (2, 3) to co-operate with threaded inserts (8) mounted in the inner frame (2). At least the inner frame (2), and preferably both frames (2, 3), are hollow and have a wooden insert, which in the case of the inner frame (2), provides a secure mounting for the threaded inserts (8). <IMAGE>

Description

SECURITY SCREEN FOR A WINDOW This invention relates to a security screen for a window.

It is known to fix a polycarbonate panel across the inside of a window, to improve security of commercial premises, by screwing through the sheet directly into the window frame, possibly using a wooden bead on the outer surface of the panel. In this way even if the window pane is broken entry to the premises or insertion of a weapon through the window can be restricted.

However, with this known arrangement the problem arises that because the polycarbonate panel is securely attached to the window frame it may not be convenient to remove the panel on a regular basis to enable routine tasks such as cleaning of the window to be carried out in a quick and easy manner.

It is an object of the present invention to provide a security screen which is convenient to remove yet with which secure attachment and good security can be ensured even after frequent removal and replacement thereof.

According to the invention therefore there is provided a security screen for a window comprising a protective panel arranged to be fixed across the window with a mounting structure, wherein said mounting structure comprises an inner rigid frame adapted to be securely attached around the window, and an outer rigid frame which is arranged to be securely but removably attached to said inner frame with the protective panel retained therebetween, the attachment of the outer frame to the inner frame being arranged to be effected by means of fixing elements passed through the outer frame and releasably engaged with co-operable fixing devices mounted in the frist frame.

The protective panel may be transparent and may be formed from a tough plastics material such as polycarbonate. The panel may have a plurality of holes provided around its periphery for said fixing elements. These holes may be equi-spaced around the periphery or may be at irregular intervals and may be circular or elongate.

Preferably elongate holes extending transversely to the panel edges are used since these permit slight lateral movement due to expansion or impact etc. The panel may be fixed to the outer frame by, for example, double sided tape or bonding or otherwise. In this way conveniently the panel can be removed and replaced together with the outer frame.

The inner and outer frames may be solid or hollow and may be constructed as a one-piece body or may be built up from sections securely joined together at respective joints.

In a particularly preferred embodiment at least the inner frame, and preferably each frame, is constructed from hollow sections containing wooden inserts, such inserts giving added strength and in the case of the inner frame providing a structure in which the fixing devices can be readily securely mounted.

The fixing devices may comprise threaded inserts, and the fixing elements may comprise corresponding threaded bolts.

In one embodiment the threaded bolts may have recessed heads for engagement with a key or the like.

The inner frame may be attached to the window frame or brickwork by screws around its periphery.

The invention will now be described further by way of example only and with reference to the accompanying drawings in which: Figure 1 is a sectional side view of one form of security screen according to the invention in position fixed across a window; and Figure 2 is an elevation of a frame of the screen.

The screen comprises a transparent polycarbonate panel 1 and a mounting structure consisting of an inner frame 2 and an outer frame 3, the inner frame 2 being adapted to be secured around a window 16 and the outer frame 3 being adapted to engage with the inner frame 2.

The polycarbonate panel 1 is cut to the desired shape and dimensions from a sheet of, say, 6mm thick LEXAN (RTM) polycarbonate sheeting. The panel 1 has spaced elongate holes 4 drilled around its periphery at positions slightly spaced from the panel edges, each hole being elongated in a direction perpendicular to the respective such edge.

Both frames of the mounting structure are constructed from hollow steel or aluminium sections 5 (say one inch (2.54cm) square) joined at adjacent ends by corner pieces 6 having spigots inserted into the hollow sections. The sections of the frames 2, 3 contain tightly inserted wooden batons 7 to improve rigidity and to provide a secure mounting for threaded barbed inserts 8. The sections of the frames 2, 3 and the wooden batons have spaced circular holes 9 drilled through them, the holes in the inner frame being aligned with, but of larger diameter than, those in the outer frame.

The threaded inserts 8 are metal tubes or bosses which are threaded on their internal surfaces and have projecting barbs on their external surfaces. Each insert 8 is tightly fixed within a respective hole in the inner frame 2, the insert being held securely in position by engagement of the external barbs with the wooden baton. The inner threaded surface of each insert is adapted to co-operate with a bolt 10 which is a solid metal bolt being adapted at one end 11 to engage with the threaded insert and at the other end having an enlarged head 12 with a hexagonal recess 13 for engagement with an Allen key.

The inner and outer frames 2, 3 are constructed with desired dimensions to suit the window to be protected. A particular advantage of the arrangement described is that the frame can be 'made to measure' quickly and conveniently. If the window is relatively large there may be one or more intermediate bars extending between opposite sides of the frame and linked thereto by means of T-joint spigot pieces.

The inner frame 2 is securely attached to the window frame 16 by spaced screws 14 around its periphery passed through pre-drilled holes. The threaded inserts 8 are fixed into the inner frame 2 through the holes 4 provided.

The' outer frame 3 has the polycarbonate panel 1 attached to it by double sided tape 15, with the elongate holes 4 in the polycarbonate panel 1 aligned with the circular holes 9 in the outer frame 3. The outer frame 3 is placed in position over the inner frame 2 with the holes 9 aligned with the respective threaded insert 8.

The two frames 2, 3 can then be securely fixed together by passing the bolts 10 through the holes 9 in the outer frame 3 to engage with the respective threaded insert 8 in the inner frame 2.

The bolts 10 are tightened to a desired degree using an Allen key so as to clamp the polycarbonate panel tightly therebetween. When desired the polycarbonate panel 1 can be removed easily with the outer frame 3 by releasing the bolts 10.

With this arrangement it is possible to provide a strong security screen for windows, whilst allowing easy and convenient removal of the screen if desired. Furthermore the engagement between the insert 8 and the bolt 10 remains secure, even if the outer frame 3 is removed frequently. Although the frame is relatively massive and rigid, it can be of relatively attractive appearance since the hollow sections can be of neat appearance and may be plastics coated or anodised as desired.

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only.

Claims

1. A security screen for a window comprising a protective panel arranged to be fixed across the window with a mounting structure, wherein said mounting structure comprises an inner rigid frame adapted to be securely attached around the window, and an outer rigid frame which is arranged to be securely but removably attached to said inner frame with the protective panel retained therebetween, the attachment of the outer frame to the inner frame being arranged to be effected by means of fixing elements passed through the outer frame and releasably engaged with co-operable fixing devices mounted in the first frame.

2. A security screen according to claim 1, wherein said protective panel is formed from a transparent plastics material.

3. A security screen according to claim 2, wherein said protective panel is formed from polycarbonate.

4. A security screen according to any one of claims 1 to 3, wherein said panel has a plurality of holes provided around its periphery for said fixing elements.

5. A security screen according to claim 4, wherein said plurality of holes comprise elongate holes extending transversely to the panel edges whereby lateral movement is permitted due to expansion or impact.

6. A security screen according to any one of claims 1 to 5, wherein said protective panel is fixed to said outer frame whereby the panel and outer frame are removable and replaceable as one structure.

7. A security screen according to any one of claims 1 to 6, wherein said inner and outer frames are of hollow section.

8. A security screen according to claim 7, wherein at least said inner frame contains wooden inserts, in which the fixing devices can be securely mounted.

9. A security screen according to any one of claims 1 to 8, wherein said inner and outer frames are built up from sections joined together at respective joints.

10. A security screen according to any one of claims 1 to 9, wherein said fixing devices comprise threaded inserts and said fixing elements comprise correspondingly threaded bolts.

11. A security screen according to claim 10, wherein said threaded bolts have recessed heads for engagement with a key.

12. A security screen according to any one of claims 1 to 11, wherein said inner frame is adapted for attachment to a window frame or brickwork by screws around its periphery.

13. A security screen substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.