AU2020100735B4

AU2020100735B4 - Security screen frame

Info

Publication number: AU2020100735B4
Application number: AU2020100735A
Authority: AU
Inventors: Mile Krstanoski
Original assignee: Securemesh Pty Ltd
Current assignee: Securemesh Pty Ltd
Priority date: 2019-06-11
Filing date: 2020-05-08
Publication date: 2020-10-08
Anticipated expiration: 2028-05-08
Also published as: AU2019226147B1; AU2020100735A4; AU2019101066A4; AU2019101066B4

Abstract

A frame for a security screen, comprising at least one frame member that comprises an end wall and opposed first and second side walls that together form a channel for receiving an edge section of the security screen, the channel being adapted such that first and second channel inserts are insertable into the channel in turn one before and one after the edge section is inserted into the channel such that the edge section is sandwiched between the channel inserts. A hook inwardly protrudes into the channel from the second of the side walls, wherein the hook is adapted to engage with and secure an L-shaped end section of the first of the channel inserts within the channel. A plurality of teeth inwardly protrude into the channel from the first of the side walls, wherein each of the teeth comprises an uppermost surface and a lowermost surface, wherein the uppermost surface slopes downwardly towards the end wall and the lowermost surface is aligned substantially at an angle of ninety degrees or less relative to the first of the side walls.

Description

SECURITY SCREEN FRAME Field

[0001] The present invention relates to a frame for a security screen.

Background

[0002] Screen doors are ancillary doors that are mounted in a building's doorway external to the main door. Screen doors are occasionally referred to as security screens and typically comprise an outer metal frame assembly that borders and retains a rectangular screen therein. The screen may comprise a metal mesh screen or similar flat metal structure. In hot climates, screen doors enable the main door of a building to be left open and provide a barrier that stops flying insects and airborne debris from entering into the building while allowing for ventilation. In cold climates, screen doors are used to protect the main doors of buildings from bad weather.

[0003] Screen doors must be constructed so that they provide a strong and resilient barrier to keep the building secure from intruders when the main door is open. The screen is, therefore, often comprised of heavy gauge woven stainless steel mesh and the frame assembly is often made of tough extruded aluminium.

[0004] To attach the screen within the frame assembly, the edges of the screen may slot into an inwardly-facing channel that extends around the perimeter of the frame assembly. Each edge may be secured in the channel using one or more wedge member inserts that are pushed forcefully into the channel either side of the screen edge after the screen has been slotted into the channel. This attachment mechanism provides some degree of strength and resistance but is not impervious to intruders. For example, using the right tools the inserts can easily be prised out of the channel. Further, when a sufficiently large force is applied to the screen this can cause one or more of its edge sections to be pulled out of the channel.

[0005] In this context, there is a need for improved security screen frames.

Summary

[0006] According to the present invention, there is provided a frame for a security screen, comprising: at least one frame member comprising an end wall and opposed first and second side walls that together form a channel for receiving an edge section of the security screen, the channel being adapted such that first and second channel inserts are insertable into the channel in turn one before and one after the edge section is inserted into the channel such that the edge section is sandwiched between the channel inserts; a hook inwardly protruding into the channel from the second of the side walls, wherein the hook is adapted to engage with an L-shaped end section of the first of the channel inserts and retain the first of the channel inserts in the channel; and a plurality of teeth inwardly protruding into the channel from the first of the side walls, wherein each of the teeth comprises an uppermost surface and a lowermost surface, wherein the uppermost surface slopes downwardly towards the end wall and the lowermost surface is aligned substantially at an angle of ninety degrees or less relative to the first of the side walls.

[0007] The lowermost surface may be aligned substantially perpendicular to the first of the side walls.

[0008] The uppermost surface may be aligned at an obtuse angle relative to the first of the side walls.

[0009] The hook may comprise an uppermost surface that slopes downwardly towards the end wall and a lowermost surface that is substantially perpendicular to the second of the side walls.

[0010] The first of the side walls may comprise a flat wall section extending from an uppermost end of the first of the side walls down to an uppermost tooth of the teeth.

Brief Description of Drawings

[0011] Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is an isometric view of an individual frame member of a security screen frame according to an example embodiment of the invention; Figure 2 is a side cross-sectional view of an uppermost section of the frame member of Figure 1, wherein the frame member is shown with a first channel insert disposed therein; Figure 3 is a further side cross-sectional view of the uppermost section of the frame member of Figure 1, wherein the frame member is also shown with a screen edge section and second channel insert disposed therein; Figures 4(a) and 4(b) are isometric views of, respectively, first and second channel inserts of the frame member of Figure 1; Figure 5 is an elevated plan view of an example screen installed in the frame assembly; Figure 6 is an isometric view of an individual frame member of a security screen frame according to a further example embodiment of the invention, wherein the frame member is shown with first and second channel inserts disposed therein; and Figure 7 is a side cross-sectional view of an uppermost section of the frame member of Figure 6 shown with first and second channel inserts.

Description of Embodiments

[0012] Referring to Figures 1 to 5, there is provided a frame 10 for a security screen 12. The frame 10 comprises at least one frame member 14 that comprises an end wall 16 and opposed first and second side walls 18,20 that together form a channel 22 for receiving an edge section 24 of the security screen 12, the channel 22 being adapted such that first and second channel inserts 26,28 are insertable into the channel 22 in turn one before and one after the edge section 24 is inserted into the channel 22 such that the edge section 24 is sandwiched between the channel inserts 26,28. A hook 30 inwardly protrudes into the channel 22 from the second of the side walls 20, wherein the hook 30 is adapted to engage with an L-shaped end section 32 of the first of the channel inserts 26 and retain the first of the channel inserts 26 in the channel 22. A plurality of teeth 34 inwardly protrude into the channel 22 from the first of the side walls 18, wherein each of the teeth 34 comprises an uppermost surface 36 and a lowermost surface 38, wherein the uppermost surface 36 slopes downwardly towards the end wall 16 and the lowermost surface 38 is aligned substantially at an angle of ninety degrees or less relative to the first of the side walls 18.

[0013] More particularly, in the example depicted the lowermost surface 38 of each of the teeth 34 is aligned substantially perpendicular to the first side wall 18. In other examples, the lowermost surface 38 may be aligned relative to the first side wall 18 at an acute angle less than ninety degrees. The uppermost surface 36 of each of the teeth 34 may be aligned at an obtuse angle relative to the first side wall 18.

[0014] Referring to Figure 2, the hook 30 may comprise an uppermost surface 40 that slopes downwardly towards the end wall 16 and a lowermost surface 42 that is substantially perpendicular to the second side wall 20. The first side wall 18 may comprise a flat wall section 44 extending from an uppermost end 46 of the first side wall 18 down to an uppermost tooth of the teeth 34. The corner of the first side wall 18 at its uppermost end 46 may be rounded.

[0015] Each of the teeth 34 may comprise a pointed apex and the first channel insert 26 may comprise a deformable side portion 48. It will be understood that when the second channel insert 28 is pushed forcefully into the channel 22 between the screen edge section 24 and the second channel side wall 20, the screen edge section 24 is urged towards the teeth 34. Consequently, the first channel insert 26 and deformable side portion 48 are also urged towards the teeth 34. The teeth 34 are dimensioned such that their pointed apexes press into the deformable side portion 48. This, in turn, causes each of the teeth 34 to deform and form an indentation in the deformable side portion 48. The frame member 14 may comprise a total of three of the teeth 34 that are arranged consecutively along an upper section of the first side wall 18 in abutting contact with each other. Having three teeth 34 advantageously provides that the teeth 34 apply substantial pressure onto the deformable portion 48 when the second insert 28 is pushed into the channel 22 and is economical in terms of weight and manufacturing cost.

[0016] The deformable side portion 48 may be elastically deformable. In such examples, when the teeth 34 are being pressed into the deformable side portion 48, the elastic qualities of the deformable side portion 48 provide that it offers resistance to the teeth 34. This resistance may cause the pointed apexes of the teeth 34 to pierce the surface of the deformable side portion 48 and penetrate into the deformable side portion 48 to a particular depth.

[0017] The relative dimensions of the channel 22, the teeth 34 and the first channel insert 26 preferably provide that the teeth 34 pierce the deformable side portion 48 to a depth that allows the teeth 34 to engage the first channel insert 26 effectively without adversely affecting its structural strength. That is to say, the pointed apexes of the teeth 34 obtain a strong hold on the channel insert 26 without damaging its structural integrity. If the apexes were to pierce the deformable side portion 48 to an excessive depth, the structural integrity of the channel insert 26 could be compromised thereby enabling it to be easily picked or pulled out of the channel 22 by an intruder. In one example, the teeth 34 may pierce the surface of the deformable side portion 48 and protrude therein to a depth of substantially between 0.5 and 1.4 millimeters. More particularly, in preferred embodiments a depth of about 1.4 millimeters provides that the teeth 34 advantageously engage the deformable side portion 48 and first channel insert 26 effectively without compromising its structural strength.

[0018] In other examples, the frame member 14 may be dimensioned such that the teeth 34 deform the deformable side portion 48 without piercing its surface. The teeth 34 may simply occupy the indented spaces that they form in the deformable side portion 48. The deformable side portion 48 may be elastically or plastically deformable in such examples.

[0019] The first and second channel inserts 26,28 may each be made of flexible polyvinyl chloride (PVC) and/or natural or synthetic rubber-based materials. It will be understood that the channel inserts 26,28 may be made of one or more other materials having the requisite firmness that enable them to secure the screen edge section 24 effectively in the channel 22 yet are also suitably deformable, at least in part, such that the teeth 34 are able to press into the deformable side portion 48.

[0020] The first channel insert 26 may comprise a second side portion 50 that is aligned parallel to the deformable side portion 48 and is made of a material that is harder than the deformable side portion 48. More particularly, the second side portion 50 may be made of a material that is between 2 and 2.5 times harder than the deformable side portion 48. For example, the deformable side portion 48 may be made of a material having a hardness of between 30 to 50 on the Shore 00 hardness scale and the second side portion 50 may be made of a material having a hardness of between 80 to 100 on the Shore 00 hardness scale.

[0021] The deformable side portion 48 may be formed integrally with the second side portion 50, such as via a co-extrusion process, to produce the first channel insert 26. For example, a pair of extruders may be used to melt and deliver a steady volumetric throughput of the respective materials used for the deformable side portion 48 and second side portion 50. The two materials may then be forced through a single extrusion head (die) to extrude the two materials together and form the finished channel insert 26. In other examples, the deformable side portion 48 and second side portion 50 may be manufactured separately and then affixed together using an appropriate attachment means, such as glue.

[0022] The deformable side portion 48 may also comprise a rough or textured surface 52 that faces the teeth 34. For example, the surface may comprise a series of striations formed therein which have been exaggerated in size in the Figures for the purpose of illustration. The textured surface 52 provides a visual indication of the location of the deformable side portion 48 which may assist the installer.

[0023] The second channel insert 28 and the second side wall 20 may comprise co-operating locking means for locking the second channel insert 28 in the channel 22 once inserted therein. For example, the second channel insert 28 and second side wall may comprise a plurality of interconnecting projections and recesses 54 that, together, provide the co-operating locking means. The interconnecting projections and recesses 54 may be oriented diagonally relative to longitudinal axes of the second channel insert 28 and second side wall 20. In this configuration, the projections and recesses 54 inhibit removal of the second channel insert 28 from the channel 22 when the insert 28 has been forced therein.

[0024] The L-shaped end section 32 of the first channel insert 26 may extend transversely from a lowermost end of the first channel insert 26. The L-shaped section 32 is adapted to fit underneath a lowermost end of the screen edge section 24 to provide a barrier that spaces the edge section 24 apart from the end wall 16. It will be understood that when the screen 12 and frame member 14 are made of two different types of metal (for example, steel and aluminum respectively) galvanic or dissimilar metal corrosion may take place at or near to the boundary between the two metals if they are in abutting contact. The barrier provided by the L-shaped section 32, therefore, advantageously, avoids such corrosion.

[0025] The hook 30 may inwardly extend into the channel 22 from a lower end of the second side wall 14. Together with the end wall 16 of the channel 22, the hook 30 may define a rectangular-shaped cavity 56 that is adapted to receive an endmost part of the L-shaped section 32 when the first channel insert 26 is inserted into the channel 22. The hook 30 impedes removal of the first channel insert 26 from the channel 22 when the endmost part of the L-shaped section 32 is disposed in the cavity 56. The lowermost surface 42 of the hook 30 may be at least 1.5 millimeters in length and protrude inwardly into the channel 22 from the first side wall 20 by such distance. The relative dimensions of the cavity 56 and the L-shaped section 32 may provide that the endmost part of the L-shaped section 32 may be spaced apart from the cavity 56 when inserted therein.

[0026] The first channel insert 26 may comprise a lip member 58 that extends transversely from an uppermost end of the first channel insert 26. The lip member 58 is configured to abut, at least partially, the uppermost end 46 of the first side wall 18 when the two inserts 26, 28 have been pushed fully into the channel 22.

[0027] The first and second channel inserts 26,28 may also comprise a plurality of toothed members 60,62 that project inwardly into the channel 22 for engaging the edge section 24 of the screen 12. Each of the toothed members 60,62 may comprise a tapered uppermost surface and a flat lowermost surface that projects perpendicularly into the channel 22.

[0028] In use, to install the screen 12 in the frame assembly 10 each edge section 24 of the screen 12 is secured into the channel 22 of an individual frame member 14 of the frame assembly 10. For example, Figure 3 shows an individual frame member 14 in cross section with a single frame edge section 24 secured therein.

[0029] Before the frame edge section 24 is inserted, the first channel insert 26 is slotted into the channel 22, as shown in Figure 2. The channel insert 26 is inserted such that the endmost part of its L-shaped section 32 enters the cavity 56. The sloped uppermost surfaces 36 of the teeth 34 advantageously enable the first insert 26 to be pushed into the channel 22 with ease. The relative sizes and dimensions of the L-shaped section 32 and the cavity 56 provide that the endmost part of the L-shaped section 32 is spaced apart from the cavity 56 and does not form a tight fit therein. This advantageously allows the person who is performing the installation to place the insert 26 into the channel 22 and then manipulate the insert 26 until it is in the required position and orientation with ease.

[0030] The hook 30 provides an obstruction that conveniently inhibits removal of the insert 26 from the channel 22 during the installation procedure. In particular, the lowermost surface 42 of the hook 30, which is perpendicular to the second side wall 20, bears against the endmost part of the L-shaped section 32 when the insert 26 is pulled away from the cavity 22. For example, it will be understood that if the frame member 14 is located at the top of the frame 10 in a doorway and the channel 22 is facing downwardly, gravity will act downwardly on the insert 26 once it has been inserted into the channel 22. The hook 30, therefore, stops the insert 26 from falling out of the channel 22. The hook 30 similarly assists the installer when the frame member 14 is oriented vertically at one of the sides of the frame 10 in the doorway during the installation procedure.

[0031] After the first channel insert 26 has been placed correctly into the channel 22, the screen edge 24 may then be slotted into the channel 22 in the gap formed between the first insert 26 and the second side wall 20. The second channel insert 28 may then be inserted forcefully into the gap between the screen edge 24 and the second side wall 20. When the second insert 28 is forced in, the first and second inserts 26, 28 each apply an inward compressive force on the screen edge 24 causing the toothed members 60,62 to bite into the screen edge 24. In examples where the screen 12 is comprised of metal mesh, the toothed members 60,62 may enter directly into the perforations in the mesh. The pressure that is exerted by the second channel insert 28 on the second side wall 20 causes the projections and recesses 54 to mate together thereby locking the second insert 28 in place.

[0032] Further, when the second channel insert 28 is pushed into the channel 22, the pressure exerted by the teeth 34 on the first channel insert 26 causes each of the teeth 34 to press into the deformable side portion 48. This causes the teeth 34 to deform the deformable side portion 48 and thereby form a plurality of indentations therein, as shown in Figure 3. The pointed apexes of the teeth 34 may also pierce a surface of the deformable side portion 48. The flat wall section 44 advantageously allows the topmost section of the insert 26 to lie flat against the first side wall 18 when the second channel insert 28 has been forced fully into the channel 22.

[0033] The series of indentations formed by the teeth 34 in the deformable side portion 48 advantageously provide that the first channel insert 26 is held clamped in the channel 22 in a strong and resilient manner. The resultant connection achieved withstands any forces acting to pull the first channel insert 26 out of the channel 22. This includes, for example, when an intruder is attempting to pick or urge the first channel insert 26 out of the channel 22 or when large forces are exerted on the screen 12. Because the lowermost surfaces 38 of the teeth 34 are perpendicular to the first side wall 18, the lowermost surfaces 38 advantageously provide firm resistance to such pulling forces. This is similarly the case in examples where the teeth 34 are shaped such that their lowermost surfaces 38 are aligned relative to the first side wall 18 at angles less than ninety degrees.

[0034] Referring to Figures 6 and 7, there is provided an individual frame member 70 of a frame assembly according to a further example embodiment of the invention. The frame member 70 is materially the same as the frame member 14 depicted in Figures 1 to 3 except that the lip member 72 of its first channel insert 74 is dimensioned such that it extends fully across the uppermost end 76 of the first side wall 78 of the frame member 70 flush with its outermost surface 80.

[0035] Further, the second channel insert 82 is comprised of two portions, being an outer portion 84 that engages with the second side wall of the channel and an inner portion 86 that comprises the toothed members that engage with the edge section of the screen. The outer portion 84 may be made of a hard, rigid material, such as a hard PVC-based material, and the inner portion 86 may be made using a softer material, such as a softer PVC-based material. The two portions 86,88 may be formed using a co-extrusion process, or formed separately and then fixed together.

[0036] For the purpose of this specification, the word "comprising" means "including but not limited to", and the word "comprises" has a corresponding meaning.

[0037] The above embodiments have been described by way of example only and modifications are possible within the scope of the claims that follow.

Claims

1. A frame for a security screen, comprising: at least one frame member comprising an end wall and opposed first and second side walls that together form a channel for receiving an edge section of the security screen, the channel being adapted such that first and second channel inserts are insertable into the channel in turn one before and one after the edge section is inserted into the channel such that the edge section is sandwiched between the channel inserts, wherein the first of the side walls comprises a flat wall surface extending upwardly from the end wall; a hook provided on the second of the side walls, the hook comprising an uppermost hook surface and a lowermost hook surface, wherein the uppermost hook surface slopes downwardly towards the end wall, and wherein the lowermost hook surface inwardly extends into the channel from a lower end of the second of the side walls to a peripheral end of the uppermost hook surface, the lowermost hook surface thereby defining a cavity at a lowermost end of the second of the side walls, the cavity being adapted to receive an endmost part of a lowermost L-shaped end section of the first of the channel inserts to retain the first of the channel inserts in the channel; and a plurality of teeth provided on the first of the side walls, each of the teeth comprising an uppermost surface and a lowermost surface, wherein the uppermost surface slopes downwardly towards the end wall and the lowermost surface is aligned substantially at an angle of ninety degrees or less relative to the first of the side walls and meets with the uppermost surface at a pointed apex, the teeth being arranged immediately above the flat wall surface such that the pointed apex of each of the teeth inwardly projects into the channel beyond the flat wall surface to thereby cause the teeth to press into the first of the channel inserts when the first of the channel inserts is pressed against the flat wall surface.

2. The frame according to claim 1, wherein the lowermost surface is aligned substantially perpendicular to the first of the side walls.

3. The frame according to claim 1 or 2, wherein the uppermost surface is aligned at an obtuse angle relative to the first of the side walls.

4. The frame according to any one of the preceding claims, wherein the lowermost hook surface is substantially perpendicular to the second of the side walls.

5. The frame according to any one of the preceding claims, wherein the first of the side walls comprises a flat wall section extending from an uppermost end of the first of the side walls down to an uppermost tooth of the teeth.