AU7878098A

AU7878098A - Security screen and extrusion therefor

Info

Publication number: AU7878098A
Application number: AU78780/98A
Authority: AU
Inventors: Brian Peter Bond
Original assignee: REZON Pty Ltd
Current assignee: Individual
Priority date: 1997-08-04
Filing date: 1998-08-04
Publication date: 1999-02-11
Anticipated expiration: 2018-08-04
Also published as: AU748382B2

Description

P100/011 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Name of Applicant: Actual Inventor REZON PTY LTD Brian Peter Bond Address for service is: WRAY ASSOCIATES 239 Adelaide Terrace Perth, WA 6000 Attorney code: WR Invention Title: Security Screen and Extrusion Therefor Details of Associated Provisional Application No: PO 8400 filed 4 August 1997 The following statement is a full description of this invention, including the best method of performing it known to me:- -2- This invention relates to the field of security!anti-intruder screens and fly-wire screens for windows and doors.

Hitherto, screens have comprised an aluminium frame, with a wire or fibreglass mesh secured therein usually by interference fit with a flexible plastic or rubber strip which is forced into a channel along with the mesh, so securing and tensioning mesh in the frame. Such arrangements are adequate for preventing access by insects, but offer no resistance to access by unauthorised persons.

A solution to prevent access by unauthorised persons has been to include a heavy gauge mesh, usually of aluminium, which is fitted into the frame in a S 10 recess designed to accommodate it. However, the aesthetic appearance of the heavy grade mesh is not pleasing, and the level of security offered is not as great as might be supposed by a casual observer. In fact, such heavy grade mesh in aluminium can be cut with side cutters, and access to the building may be gained through such a security screen, in a matter of minutes.

The inventor has been investigating an alternative using stainless steel mesh of a grade sufficiently heavy to be substantially rigid. The inventor has determined that such mesh, if powder coated in black, becomes from a distance substantially invisible to the eye, taking on an appearance not unlike window tinting. Furthermore if the grade of the stainless mesh is sufficiently thick, it can resist attack by a would be intruder at least for as long a time as the aforementioned heavy grade mesh of aluminium.

However, there lies a problem with securing such a stainless steel mesh in an aluminium frame, due to the rigidity of the mesh. While it could be proposed to secure the mesh with screws, such a method of attachment can detract from the appearance of the screen, where those screws are visible from within the room in which the screen is fitted (over a door or window opening).

-3- Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

In accordance with the invention there is provided a method of attaching a substantially rigid mesh to a frame prescribing a border and support therefor, comprising forming a folded back portion along the edge of said mesh, the folded back portion depending from the mesh at an acute angle; and providing a recess in said frame to receive said folded back portion, said recess having means to interfere with the exposed edge of said folded back portion to retain said folded back portion in said recess, the means to interfere being formed integrally with said frame.

~Also in accordance with the invention there is provided a screen construction for a door frame or window frame, comprising a substantially rigid mesh having a folded back portion formed along the edge thereof at an acute angle, a frame prescribing a border and support for the mesh, the frame having a recess formed therein into which the folded back portion is received, the recess having means to interfere with the exposed edge of said folded back portion to retain S" h en itre bi formed said folded back portion in said recess, the means to interfere being formed 20 integrally with said frame.

The means to interfere may comprise at least one axial rib extending along the Sinterior of said recess. Preferably, the rib is provided with an inclined surface facing the opening of the recess, over which the folded back portion may ride, before latching in place behind the rib.

In a preferred arrangement, a plurality of axial ribs are provided on one wall of the recess in parallel disposition to each other.

i:- -4- Preferably, the wall opposing said one wall is provided with a roughened surface, to promote gripping of the mesh adjacent to the folded back portion.

The roughened surface may conveniently comprise a plurality of grooves.

The mesh intended to be utilised in the invention is most preferably a stainless steel mesh having a strand thickness of 0.5 mm or more. Suitable stainless steel meshes comprise those having a strand thickness of 0.71 mm with a strand spacing in the mesh of 12 strands per inch. For a stronger screen, a strand thickness of 0.85 mm or 1.1 mm, with a strand spacing in each direction of per inch should prove suitable.

Preferably, the angle of the folded back portion relative to the mesh is at least 100. A preferred angle is in the range of 200 to 600, with a range of 250 to 450 being most preferred.

An embodiment of the invention will now be described in the following description, made with reference to the drawings in which: Figure 1 is a perspective view of a screen door made according to the Sembodiment; Figure 2 is an exploded view of the components comprising the screen door of Figure 1; Figure 3 is a perspective view from above of a frame extrusion utilised in the embodiment; Figure 4 is a perspective view from above of the frame extrusion shown in Figure 3 showing fitting of mesh screen therein; Figure 5 is a perspective view from below of the frame extrusion utilised in the embodiment; Figure 6 is a perspective view from below of the frame extrusion shown in Figure 5 showing fitting of mesh screen therein; Figure 7 is a cross-section view of the frame extrusion utilised in the embodiment; and Figure 8 is a cross-section view of the frame extrusion shown in Figure 7 showing fitting of mesh screen therein.

As can be seen in Figure 1, the screen door 11 comprises a stainless steel mesh screen 13 supported in a frame 15 comprising four frame portions 17 .joined at mitred joints 18. One of the vertical frame portions 17a is provided with two hinges 19 for fixing the screen door in a door frame, while the other vertical frame portion 17b is provided with a lock 21 and latch members 23 to allow the door to be closed and locked in the normal manner.

Referring to Figure 3, 5, and 7, the aluminium extrusion comprising the frame portions 17 in this embodiment is shown. The aluminium extrusion has a box section portion 25 which forms the main structural part of the frame 15. It will be understood that the box section portion 25 may vary in shape, depending upon the purpose of the frame, however the aluminium extrusion illustrated is S.:i intended to be employed in a frame for a door. In the case of a frame for a window, it will be understood that the box section portion 25 would be smaller.

Extending from the box section portion 25, toward what would be the centre of the screen door are two upstanding arms 27 and 29, which define therebetween, a recess 31 which is intended to receive the stainless steel mesh 33 comprising the screen 13. Located on one wall of the one of the arms 29 are three parallel ribs 35, each of which has an inclined surface 37 facing the opening of the recess 31, and an abrupt vertical wall 39 opposing the inclined surface 37.

Located on the wall opposing arm 29, on arm 27, is a roughened surface in the form of parallel grooves 41.

Referring to Figure 8, the edge of the mesh 33 is formed with a folded back portion 43 along its edge 45. The folded back portion 43 is disposed at an acute angle relative to the remainder of the mesh, in the order of 300. The folded back portion extends along the entire edge of the screen 13, with the exception of the corners, as shown in Figure 2. The distance between the exposed edge of the folded back portion 43 of the mesh, and the main surface of the mesh, slightly exceed the gap between the arms 27 and 29, so that when the mesh is inserted in the recess 31, it is under compression. The folded back portion 43 of the mesh is pressed into the recess 31, so that the exposed edge thereof 47 rides up the inclined surface 37. Once over the top of the rib, the folded back portion 43 of the mesh will "click" against the abrupt vertical wall 39 of the rib 35, and be held thereagainst preventing withdrawal of the mesh from the recess 31. The Smain face of the mesh screen will abut against the parallel grooves 41, providing additional grip to minimise movement of the mesh relative to the frame. It will be 15 understood that the distance between the folded back portions 43 located around the edge of the screen 13 is calculated, depending upon the spacing t'between the ribs 35, which is in turn dependent upon the size of screen door required.

4 The mesh employed In the embodiment is a stainless steel mesh having a strand thickness of 0.71 mm with a strand spacing in the mesh of 12 strands per inch, which is powder-coated with appropriately ultra-violet resistant powder coating suitable for outdoor use. The strand spacing should prove suitable for preventing access by mosquitos.

The box section portion 25 will accommodate parts of the lock and latch in the normal manner of screen doors, and in addition comer guides 45 as also utilised in the frames of hitherto known screen doors. Once the lock and latch parts 21 and 23 are fitted, the frame can be pressed together, with the mesh screen 13 in place. The folded back portions 43 can be pressed into place, tensioning the screen 13 in its frame 15. The provision of several parallel ribs 35 provides some leeway for adjustment of the screen 13. Finally, a filler strip 47 (as shown i a- -arrrm- Ln-~ ITa in Figure 8) cans be inserted into recess 31, to provide an improved appearance.

It should be appreciated that the scope of the invention is not limited to the scope of the embodiment described herein. For example, while the screen door described is of a hinged type, runners and an appropriate frame may be employed to make a sliding door. In addition, the frame may be made so that it can be fixed in place over a window opening.

Claims

1. A method of attaching a substantially rigid mesh to a frame prescribing a border and support therefor, comprising forming a folded back portion along the edge of said mesh, the folded back portion depending from the mesh at an acute angle; and providing a recess in said frame to receive said folded back portion, said recess having means to interfere with the exposed edge of said folded back portion to retain said folded back portion in said recess, the means to interfere being formed integrally with said frame.

2. A method of attaching a substantially rigid mesh to a frame as claimed in 10 claim 1 wherein the means to interfere comprises at least one axial rib extending along the interior of said recess.

3. A method of attaching a substantially rigid mesh to a frame as claimed in claim 2 wherein said rib is provided with an inclined surface facing the opening of the recess, over which the folded back portion rides, before latching in place behind the rib.

4. A method of attaching a substantially rigid mesih to a frame as claimed in claim 2 or 3 wherein a plurality of axial ribs are provided on one wall of the recess in parallel disposition to each other.

A method of attaching a substantially rigid mesh to a frame as claimed in claim 4 wherein the wall opposing said one wall is provided with a roughened surface, to promote gripping of the mesh adjacent to the folded back portion.

6. A method of attaching a substantially rigid mesh to a frame as claimed in claim 5 wherein the roughened surface comprises a plurality of grooves. s~L I _r -9-

7. A method of attaching a substantially rigid mesh to a frame as claimed in any one of the preceding claims wherein the mesh intended to be utilised in the invention is a stainless steel mesh having a strand thickness of at least mm.

8. A method of attaching a substantially rigid mesh to a frame as claimed in any one of the preceding claims wherein the angle of the folded back portion relative to the mesh is at least 100.

9. A screen construction for a door frame or window frame, comprising a substantially rigid mesh having a folded back portion formed along the edge thereof at an acute angle, a frame prescribing a border and support for the mesh, the frame having a recess formed therein into which the folded back portion is received, the recess having means to interfere with the exposed edge of said folded back portion to retain said folded back portion in said recess, the means to interfere being formed integrally with said frame-

10. A screen construction as claimed in claim 9 wherein said means to interfere may comprise at least one axial rib extending along the interior of said ,,,recess.

11. A screen construction as claimed in claim 10 wherein said rib is provided with an inclined surface facing the opening of the recess, over which the folded back portion may ride, before latching in place behind the rib.

12. A screen construction as claimed in claim 10 or 11 wherein a plurality of axial ribs are provided on one wall of the recess in parallel disposition to each other.

13. A screen construction as claimed in claim 12 wherein said wall opposing said one wall is provided with a roughened surface, to promote gripping of the mesh adjacent to the folded back portion.

14. A screen construction as claimed in claim 13 wherein said roughened surface comprises a plurality of grooves.

A screen construction as claimed in any one of claims 9 to 14 wherein said mesh is a stainless steel mesh having a strand thickness of at least 0.5 mm.

16. A screen construction as claimed in claim 15 wherein said stainless steel mesh has a strand thickness of 0.71 mm with a strand spacing in the mesh of 12 strands per inch.

17. A screen construction as claimed in claim 15 wherein said stainless steel mesh has a strand thickness of 0.85 mm or 1.1 mm, with a strand spacing in each direction of 10 per inch.

18. A screen construction as claimed in any one of claims 9 to 17 wherein the angle of the folded back portion relative to the mesh is at least

19. A screen const-uction as claimed in claim 18 wherein the angle of the folded back portion relative to the mesh is in the range of 200 to

20. A screen construction as claimed in claim 18 wherein the angle of the folded back portion relative to the mesh is in the range of 250 to

21. A screen construction substantially as herein described with reference to the description of the embodiment. Dated this fourth day of August 1998. REZON PTY LTD Applicant Wray Associates Perth, Western Australia Patent Attorneys for the Applicant I