SCREENS

Abstract

A security screen employs frame rails 11, as an extrusion of constant cross-section and having a rectangular hollow space 18 and a screen entry opening 19 opposite the hollow section 18. The rail 11 leads from the screen entry opening 19 outboard as a form of channel 20. The channel 20 has three regions comprising a screen tensioning region 21, a glue receiving region 22 and a seal or cover strip receiving region 23. The first step in assembly is to caulk or otherwise deposit a suitable glue, for example a methacrylate, epoxy, urethane or equivalent to fill the glue region 22. The screen is inserted through the glue, the frame promoting movement of the glue into the screen so that the glue hardens to form a matrix around and through the screen.

Claims

1. A security screen assembly, comprising a frame, and a rigid screen, the assembly using a hardenable material, laid into the frame while wet and allowed to harden, and to thereby hold the screen in the frame.

2. A security screen assembly according to claim 1, the frame includes a screen tensioning region within the frame, directly engaging the screen in a non-return fashion.

3. A security screen assembly according to claim 1 wherein the frame includes a screen tensioning region within the frame, directly engaging the screen in a non-return fashion, and the hardenable material occupies a region separate of the screen tensioning region.

4. A security screen assembly according to claim 1 wherein the frame includes a screen tensioning region within the frame, directly engaging the screen in a non-return fashion and wherein the screen tensioning region is an insert fitted into the frame.

5. A security screen assembly according to claim 1 wherein the hardenable material is an adhesive which includes an MMA monomer as a component, and is blocked from removal from the frame by at least one frame formation.

6. A security screen assembly according to claim 1 employing a screen tensioning region inboard or outboard of the hardenable material.

7. A security screen assembly according to claim 1, the frame comprising an outer surrounding frame and the rigid screen being a panel extending across the frame, the screen panel having a marginal outer periphery, the frame having a screen opening, the marginal outer periphery of the screen passing through the screen opening and into the frame, the hardenable material laid inside the screen opening, the material being laid while soft and allowed to harden to thereby indirectly hold the screen in the frame.

8. A security screen assembly according to claim 1 wherein the frame has three chambers holding a marginal edge of the screen.

9. A security screen assembly according to claim 1, the frame comprising an outer surrounding frame and the rigid screen being a panel extending across the frame, the screen panel having a marginal outer periphery, the frame having a screen opening, the marginal outer periphery of the screen passing through the screen opening and into the frame, the hardenable material laid inside the screen opening, the material being laid while soft and allowed to harden to thereby indirectly hold the screen in the frame, and further wherein the frame has a relatively wide interior hardenable material receiving part and an adjacent relatively narrow part, the receiving part being adapted to receive the material laid inside the frame while soft and upon hardening this indirectly prevents removal of the screen from the frame.

10. A security screen assembly according to claim 1 made according to a method for assembly, wherein frame rails of the frame assembly are connected to the screen, the screen being a panel having an outer periphery, the method comprising the steps of: (a) placing into a said frame rail, a material of the type laid while soft for the purpose of being allowed to harden; and (b) before the material hardens insert the periphery of the screen through the material into the rail; and (c) allowing the material to harden.

11. A security screen assembly according to claim 1 made according to a method for assembly, wherein frame rails of the frame assembly are connected to the screen, the screen being a panel having an outer periphery, the method comprising the steps of: (a) placing into a said frame rail, a material of the type laid while soft for the purpose of being allowed to harden; and (b) before the material hardens insert the periphery of the screen through the material into the rail; and (c) allowing the material to harden, the method further includes providing the hardenable material inside the frame as a bulged quantity of hardenable material and passing the edge of the screen panel through the hardenable material to a position in the frame beyond the bulge.

12. A security screen assembly according to claim 1 made according to a method for assembly, wherein frame rails of the frame assembly are connected to the screen, the screen being a panel having an outer periphery, the method comprising the steps of: (a) placing into a said frame rail, a material of the type laid while soft for the purpose of being allowed to harden; and (b) before the material hardens insert the periphery of the screen through the material into the rail; and (c) allowing the material to harden. the method further includes providing the hardenable material inside the frame as a bulged quantity of hardenable material and passing the edge of the screen panel through the hardenable material to a position in the frame beyond the bulge, in an additional step, the frame includes a screen tensioning region within the frame outboard of the hardenable material and this engages an edge of the screen that has passed through the hardenable material in order to tension the screen before the material hardens.

13. A security screen assembly according to claim 1 including a cover strip employed inboard of the hardenable material and clipped to the frame.

14. A security screen assembly according to claim 1 wherein an insulating strip extends along the screen.

15. A security screen assembly according to claim 1 wherein the hardenable material is held in a holding section in the frame, the holding section having a profile to promote passage of the hardenable material into spaces in the screen as the edge of the screen is moved through the hardenable material to its operative position in the frame.

16. A security screen assembly according to claim 1 wherein the hardenable material is held in a holding section in the frame, the holding section having a profile to promote passage of the hardenable material into spaces in the screen as the edge of the screen is moved through the hardenable material to its operative position in the frame, the promotion of the hardenable material being by a pumping action.

17. A security screen assembly according to claim 1 wherein the hardenable material is held in a holding section in the frame, the holding section having a profile to promote passage of the hardenable material into spaces in the screen as the edge of the screen is moved through the hardenable material to its operative position in the frame, the holding section is generally triangular in profile, having a wider inboard section to encourage backward and then inward flow of the hardenable material toward the screen as the screen displaces the hardenable material.

18. A security screen assembly according to claim 1 wherein the hardenable material is held in a holding section in the frame, the holding section having a profile to promote passage of the hardenable material into spaces in the screen as the edge of the screen is moved through the hardenable material to its operative position in the frame, the holding section having wider sections include projections, as well as curved surfaces to divert the hardenable material into and through the progressing screen as it is progresses into its operative position in the frame.

19. A security screen assembly according to claim 1, the frame having a screen retainer area that contains ribs, fins or teeth or the like with which the hardenable material forms around and also through the screen and together prevents the dried form of the hardenable from pulling out of the retainer area.

20. A security screen assembly according to claim 1, wherein the frame having a recessed screen retainer area having recessed elongated groove channels with which the hardenable material forms and prevents the dried/hardened resulting structure from pulling out of the recessed retainer area.

21. A security screen assembly according to claim 1 wherein the frame has an elongated screen retainer area having chambers and a narrow neck forming a screen opening.

22. A security screen assembly according to claim 1 including a screen retainer having a deformable inner retainer area that creates channels and pockets with which the hardenable material can form and mould into to interact with the screen providing one solid integral retainer once dried.

23. A security screen assembly according to claim 1, the hardenable material is formed as a unitary matrix about and through the screen, the frame having a profile including multiple chambers, at least one chamber having a screen tension region including projections engaged with the screen and another of the said chambers having surfaces adapted to direct hardenable material into the screen to aid formation of the matrix about and through the screen.

24. A security screen assembly according to claim 1 wherein the hardenable material comprises a modified MMA and hardener to the following specifications: (a) Minimum working time of compound 20 minutes (30-40 ideal) before hardening commences. (b) Relatively high viscosity so that compound doesn't “leak” back out of frame when laid flat. (c) Minimum tensile lap shear strength of 2,900 psi or 20 mpa (d) Tensile modulus of between 30,000-40,000 psi or 200-300 mpa (e) The MMA consists of an adhesive having a viscosity rating between 200,000-250,000 centipoise & the hardener which should have a viscosity rating between 120,000-180,000 centipoise.

25. A security screen assembly according to claim 1, the hardenable material being a liquid substance that has structural capability to interact with the frame and screen to form one solid matrix blocked from separation by the frame material, that cannot pull out past these grooves, channels, teeth, ribs or the like once dried, characteristics of the matrix material being as follows: (a) High tension strength; (b) Excellent impact and peel strength; (c) Varying cure times; (d) High toughness and flexibility; (e) Minimal bond shrinkage; (f) Very high resistance to fatigue; (g) Resistant to solvents and weathering; (h) Tolerant of oily surface and other types of surface contamination.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order that the present invention may be more readily understood and put into practical effect reference will now be made to the accompanying drawings which illustrate preferred embodiments of the invention and wherein:

[0044] FIG. 1 is a perspective view of a screen assembly according to a preferred embodiment of the invention;

[0045] FIG. 2 is a frame rail profile;

[0046] FIG. 3 is the profile of FIG. 2 with a hardenable material added;

[0047] FIG. 4 shows the next step in the method with a screen edge inserted into the frame rail of FIG. 3 or the frame rail pushed over the edge;

[0048] FIG. 5 shows the finished screen rail corresponding to the section A-A of FIG. 1;

[0049] FIGS. 6 and 7 are perspective and profile views of a second embodiment employing a PVC insert as substitution for an extruded metal portion;

[0050] FIG. 8 is a perspective view showing the first step in the method;

[0051] FIG. 9 shows the second step in the method;

[0052] FIG. 10 shows final step in the method;

[0053] FIG. 11 shows a part cutaway of a corner of a frame assembly according to the invention; and

[0054] FIGS. 12 to 15 illustrate an embodiment based on the same method but locating operative parts in different positions compared to the previous two embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Method of Performance

[0055] Referring to the drawings and initially to FIG. 1 there is illustrated a frame assembly 10 comprising four frame rails 11, 12, 13 and 14 and a rigid screen 15 extending across and connected to the rails. The screen 15 in this case is woven stainless steel and has a peripheral cut edge which fits inside the frame rails and this peripheral edge is depicted in FIG. 1 in phantom at 16. The rails 11, 12, 13 and 14 are mitred at their respective ends in the usual way of forming a frame assembly, L shaped corner joiners are fitted into hollows located outboard of the peripheral edge of the screen. Cover strips 17 fit into the frame rails on opposite sides of the screen to finish off the screen assembly. The connection of the screen to the frame rails and the addition of the cover strip 17 will be described in greater detail below.

[0056] Referring now to FIGS. 2 to 5 the structure of the frame rails and the method of assembly of the screen will be described noting that FIG. 5 corresponds generally to the section through A-A of FIG. 1.

[0057] A typical profile of a frame rail corresponding to the rails 11, 12, 13 and 14 is illustrated in FIG. 2. The frame rails, for example 11, is an extrusion of constant cross-section and having a rectangular hollow space 18 and a screen entry opening 19 opposite the hollow section 18. The rail 11 leads from the screen entry opening 19 outboard as a form of channel 20.

[0058] In one preferred configuration the channel 20 has three regions comprising a screen tensioning region 21, a glue receiving region 22 and a seal or cover strip receiving region 23.

[0059] As shown in FIG. 3 once the frame rails are cut to size and the screen 15 is cut to size so it fits to the position illustrated in FIGS. 4 and 5 the first step in assembly is to caulk or otherwise deposit a suitable glue, for example a methacrylate, epoxy, urethane or equivalent to fill the glue region 22 as shown at 24 in FIG. 3. A suitable viscosity and hardening time may be selected to permit the further steps in the method. At present and at the moment of writing the Applicant has had prepared a modified MMA and hardener to the following specifications: [0060] 1. Minimum working time of compound 20 minutes (30-40 ideal) before hardening commences. [0061] 2. Relatively high viscosity so that compound doesn't “leak” back out of frame when laid flat. [0062] 3. Minimum tensile lap shear strength of 2,900 psi or 20 mpa [0063] 4. Tensile modulus of between 30,000-40,000 psi or 200-300 mpa [0064] 5. The MMA consists of an adhesive having a viscosity rating between 200,000-250,000 centipoise & the hardener which should have a viscosity rating between 120,000-180,000 centipoise.

[0065] Now as can be seen the glue region includes a bulged section which is tapered at 25 and 26 and includes protrusions 27, 28, 29 and 30 with just inboard from them sets of curved walls 31 and 32 with each of these having outboard returns 33.

[0066] Now this disposition of the curved walls and the returns results in a return flow back along the bulged sides shown and then in toward the screen 15 as the screen 15 passes through the opening 19 and effectively compresses the glue in the outboard direction of the arrows shown in FIG. 4.

[0067] As the mesh screen progresses further into the frame the glue will be caused to come back following the trajectory of the sets of curved surfaces and their returns and be effectively forced between and into the interstices in the screen as depicted generally at 34 in FIG. 4.

[0068] Now it be further appreciated that the tensioning region 21 has backward directed non-return teeth 35 and 36 on opposite side walls thereof and these will grip on to the suitably sized mesh as the frame rail is pushed on to the mesh.

[0069] Once the mesh is in the position illustration in FIG. 4 then the sealing strip 17 may be clipped into position. In this example, the sealing strips 17 have on their outside, teeth 37 corresponding to teeth 38, 39 on opposite sides of the opening 19. The strips 17 also have on their screen side softened tangs, ribs or projections which serve to seal against the mesh 15.

[0070] Now it will be appreciated that the mesh 15 along its edge 40 may have an insulating tape applied or inserted or it may be such as to draw into itself sufficient of the glue to fill the bottom section 41 with glue to insulate the screen from the aluminium extrusion corresponding to the rails 11, 12, 13 and 14.

[0071] As another alternative, as illustrated in FIGS. 6 and 7, the tensioning region in this case at 42 comprises a PVC insert 43 which may be axially slid into the frame rail element 44. The frame rail profile is in all respects is the same as the previous rail except that it now has a simple squared section at 45 used to lock the insert 43 to be reclaimed in position. Now the insert 43 is the same performance and function as the tension region but is in rigid plastics. The insert 43 may be made in different inside dimensions at 45 so that it may work with different thickness mesh screens or different screen materials. The internal structure of the insert 43 may be varied accordingly. In each case the screen is still set on edge along a central plane of the frame profile.

[0072] As may be seen in the drawings the hardenable material is desirably used to both chemically bond and also fill gaps so the range of bonding is across gaps between parts.

[0073] Referring now to FIGS. 12 to 15 there is illustrated a frame rail 46 which may be joined or connected in the usual way together with other similar rails and configured into a screen assembly similar to FIG. 1. Where appropriate like numerals illustrate like features. In this embodiment the cover strip 17 and the tension region insert 43 are made up together as a pair of inserts strips 47 and 48. These are typically rigid. These locate in T-shaped slots 49 and 50. The inserts 47 and 48 have inward facing teeth 51 or other effective ridges, projections or the like for a non-return effect to enable the screen 15 to be tensioned as it is pushed through to the position held in FIG. 15 in the glue.

[0074] The inserts have integrally formed cover sections 52 and 53 and corresponding T-shaped in profile, locating projections, that firmly fit into the T-shaped slots 49 and 50 in the frame 46.

[0075] There is a glue receiving region 54 bounded on its side walls by non-return teeth, prongs or tabs 55 to 58. These may be similar to those in previous embodiments noting that the main difference in this embodiment is the relative position of the glue receiving region 54 positioning glue at 59 outboard of the tensioning region provided by the teeth 51 inboard of the glue receiving and holding region in terms of the direction of screen travel. In the other specific embodiments the glue holding region is upstream of the screen tension region. It should also be appreciated that the screen tension section in FIGS. 12 to 15 could be extruded and integrally formed with the frame. In this case there would then be small cover strips fitted into the frame similar to the strips 17 with corresponding regions of the frame extruded to hold those strips.

[0076] It should also be noted that in the preferred method, the glue precedes the screen into the frame but that need not be the case, the screen could be inserted and then glue forced into the holding section as all that is required is that the glue infiltrate the screen and then harden and the hardened glue and screen combination be blocked against removal. The glue may be intermittent or continuous in the frame. The arrangement may be generally symmetrical about the screen in profile but need not be.

[0077] Whilst the above has been given by way of illustrative example many variations and modifications will be apparent to those skilled in the art without departing from the broad ambit and scope of the invention as herein set forth. It will further be appreciated that the drawings are not shop drawings or working drawings and that the skilled person will select and adopt suitable tolerances using standard workshop practice to optimise the connection between the screen and the frame using the hardenable material.