1 FRAME ASSEMBLY AND METHOD FOR SECURING A SCREEN IN A FRAME TECHNICAL FIELD [0001] THIS INVENTION relates to improvements in or in relation to security screens and in particular but not limited to a method by which stainless steel mesh is secured in a surrounding frame. BACKGROUND [0002] There have been a multitude of arrangements for securing a screen in a frame. The art may be described as "crowded" or a "developed" art. Problems encountered by other patent owners include the overall requirement for security as reflected by satisfying the prevailing "Official Standards", thus to make sure the screen and frame can withstand the actions of an intruder and as well as this there is the desire for efficient and economic fitting. Some patents utilise fasteners at specific intervals while others are fastenerless utilising a toothed channel in the frame and a corresponding toothed insert holding the marginal edge of the mesh. The fastener arrangement is said to be more secure but it suffers from galvanic corrosion at the fastener due to galvanic current between the aluminium and the stainless steel. Examples of different types of screen assemblies include those shown in the following Australian patent specifications: 2006202858; 2007101213; 2007216631;2007272305;2008202835;2009266412;2010241512;2011101076;2011200501; 2011218770;2005252260. [0003] In order to alleviate the problem of corrosion there have been a host of frame profiles, insulating strips and tapes used to prevent galvanic current but this means there can be extra components and sometimes rather complex assembly processes with preformed mesh, wedges and special tools all adding the wide variety of solutions. [0004] In some cases the screens may be fabricated on-site in others they are made to measure in a factory. [0005] In recent times in Patent Application AU2011200501 there has been an effort to have the 2 benefits of a secure fastener with an insulator in the form of a toothed plastic strip fitted in a correspondingly toothed channel. The screen and frame are first fitted and assembled with the toothed insulating strip around the screen and this is push fitted into the channel in the frame. [0006] This type of arrangement was used previously without fasteners before but in this latest patent application it is strengthened using spaced discrete fasteners. It tries to have the best of both worlds. The frame, strip and screen are drilled at spaced intervals and then an insulating plug is inserted into each of the drill holes and then a screw fastener is inserted inside the plug. It seems that this has been needed since through various marketing and advertising campaigns homeowners in Australia have to a degree been convinced that security is only available through the use of discrete fasteners. Therefore with products like that described in AU2011200501 there seems to be a trend back to the simple spaced fasteners of the earliest screens. Once fasteners are employed it really makes the toothed strip superfluous other than to provide an insulating function. [0007] Even though the fastener version was developed before all the later fastenerless versions and the art has become crowded, the later offerings have not been widely accepted. Consequently, there is a requirement for a fresh look at the general problems and to look "outside the box" through new eyes in an effort to provide an alternative to the efforts made over the last twenty years. It would be desirable to have something that is simple and easy to assemble yet effective. [0008] All the above security screens work and are generally made to the prevailing standards so in this sense there is nothing wrong with them and they do not in any way lead to the conclusion that there is a specific obvious problem in need of solution. [0009] This means that the present invention does not arise through any deterministic relationship to the prior art but rather is the inventor's own inspiration in an individualistic way applying his mind to the general problem of fastening a screen in a frame, this being as an alternative to what is currently available, rather than an effort to deal with any specific recognised extant problem of the prior art. SUMMARY OF INVENTION 3 [0010] With the above in mind the present invention resides in one broad aspect in a method of assembly of a security screen assembly of the type employing an outer extruded frame and a screen, preferably of woven stainless steel, the method comprising the steps of (in no particular order): 1. providing an extruded frame with an inside having a screen receiving portion, preferably an inside facing channel; 2. inserting a marginal edge portion of the screen into the frame; 3. insulating at least part of the marginal edge portion of the screen; 4. subsequent to steps 1-3, applying external compression of a punch or press to deform at least part of the assembly including the frame and preferably including the screen, in the region of the marginal edge portion of the screen in order to secure the screen to the frame. In one embodiment the frame is compressed to clamp the screen and an insert located around a marginal edge of the screen. [0011] In another embodiment the screen is deformed. In another embodiment the screen and frame are deformed. A punch, press or combined punch and press may be employed. Preferably, in the compression step, the deformation is applied on one side of the frame against a back section of the frame supporting the screen so that the deformation is simultaneously in two adjacent locations. In one step the two locations give rise to two hole punched side by side. [0012] Preferably, the deformation of the screen is at fixed spaced intervals around the frame. Typically, this is by use of punch. While the screen only need be deformed there may be deformed sections of screen, insulator or frame sections that are simultaneously deformed. In a preferred form the frame includes a space, cavity or chamber downstream of the punch travel to serve as a region for the deformed sections of screen, insulator or frame section to occupy. [0013] In one embodiment a hole is punched through a wall of the channel and also through the screen so that the screen is deformed into a collar projecting transversely into a cavity in the frame. In another embodiment a hole is not punched but rather the frame and/or screen are deformed to provide a shoulder to prevent sideways movement of the mesh in the frame. [0014] Preferably, the frame has one of more weakened zones or regions at and/or in the vicinity of 4 the area of application of the applied pressure from a punch or press or combined punch or press, these weakened zones being for the purpose of stress relief upon application of the compression arising for the method. This means that the applied force is essentially isolated from the rest of the frame in order to minimise any frame distortion that might otherwise arise from the method. The weakened zones may comprise grooves, back to back grooves, crumple zones or other sacrificial means used to distribute localised stresses in the frame arising from the method. [0015] Preferably, the edge is insulated using an insulating strip so sized and arranged so that it deforms or is punched with the screen but does not break the insulative effectiveness of the insulator. [0016] As the above method gives rise to a new screen assembly, in another aspect there is provided a screen assembly, preferably a security screen assembly comprising a frame, a screen fitted to the frame, the screen being deformed at spaced intervals about the frame and said deformations serving to retain the screen in the frame. Typically and insulating strip is used between the screen and frame. The screen may be deformed by being laterally displaced out of the plane of the frame or by having a hole punched through the screen or a combination of both. [0017] In another aspect, there comprises a screen assembly, preferably a security screen assembly, comprising a frame holding a screen, the frame includes compression points or regions around the frame applied to the frame subsequent to the screen being inserted into the frame to hold the screen in the frame. Typically, a marginal edge portion of the screen is held in the frame and an insulating strip is used between the screen and frame. As compression is applied to the frame at selected locations, this gives rise to a still further aspect where localised stress in the frame is preferably distributed by zones that break or deform along predetermined stress relieving areas for the purpose of preventing stress being carried into the frame proper and to thereby prevent distortion of the frame. [0018] In a further preferred form there is provided in a security screen assembly an extrusion having a hollow body portion, a front face, a rear face, an outside wall and an inner panel or screen receiver section, the receiver section having a first channel and second and third channels extending along an inside wall of the first channel, the first and second channels being separated by an upstand located generally in the line of travel of a punch, the punch being adapted to punch a pair 5 of holes through the first channel drive and into the second and third channels straddling the upstand. In a further aspect of this embodiment there is provided a security screen assembly having a screen held in place by pairs of holes punched at spaced intervals, the holes being punched simultaneously through a channel of a surrounding frame, a screen spacer and the screen, each pair of holes having an upstand opposite the holes on the other side of the screen and being positioned to resist the punch force. BRIEF DESCRIPTION OF THE DRAWINGS [0019] In order that the present improvements 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: Figure 1 is a part perspective view of a security screen assembly illustrating application of the method of the present invention ; Figure 2 is a section through a typical frame showing a punch being extracted after punching a hole through the frame and screen; Figures 3-5 illustrate a further embodiment where two frangible sections of the frame break while the screen and insulator are deformed without breaking; Figures 6 and 7 are sections illustrating another embodiment where the frame is not deformed but the screen is formed into the frame; Figure 8 is a section where the frame and screen are deformed; Figures 9-11 illustrate an embodiment where there is minimal compression applied; and Figures 12 and 13 illustrate the use of a combined punch and press. [0020] Referring to the drawings and initially to Figure 1 there is illustrated a corner 10 of a frame assembly for a door or window where frame members 11 and 12 are mitred in the usual way with a stainless steel screen 13 having its peripheral marginal edge 14 inserted into the frame members. An insulating strip 15 is wrapped around the marginal edge 14. The whole door or window frame may be assembled or each side in turn. Afterwards various punch options shown at 16 and 17 are used to punch holes 18 and 19 or deform the frame and screen so that the deformed screen acts as an effective fastener. A cover strip is used to cover up the deformed sections.
6 [0021] This punching takes place at spaced intervals with typically a 20 tonne punch being used. [0022] The other drawing figures illustrate various frame and punch options that are exemplary and non-limiting examples of the present invention. [0023] Referring to Figure 2 there is illustrated a door frame extrusion 20 having an inside screen receiving channel 21 where a conical punch 22 has been used to punch a hole 23 through walls 24 and 25 of the channel 21. The marginal edge 14 of the screen 13 has an insulating strip 15 and the hole 23 passes through the strip 15 and the screen and this is depicted schematically in Figure 2 so that the circular hole 23 formed by the punching of the pre-assembled elements locks the screen into the frame channel section 26. In the illustrated embodiment the section 26 includes a chamber or cavity 27 serving as a space so that the deformed section of the screen and frame have a space to occupy. [0024] Referring now to Figures 3-5 there is illustrated another embodiment of the method where in Figure 3, the frame is set up prior to punching with an extruded frame member 28 having an inside channel 29 defined by walls 30 and 31 holding an insulating strip 15 and a marginal edge 14 of a screen 13. The walls 30 and 31 have four parallel lines of weakness 32, 33, 34, 35, 36, 37, 38 and 39. The frame section 28 has cavities 40 and 41 to receive wall sections 42 and 43 when they a deformed. [0025] A punch 44 as shown in Figure 4 is aligned with the lines of weakness so that the walls 30 and 31 breakaway in the region of the applied punch and this drives the lower wall sections 42 and 43 down into the cavities 40 and 41 while deforming the screen and insulating strip as shown in Figure 4. This locks the screen in the frame this is repeated progressively around the frame. [0026] The punch 44 has an annular wall 45 and an annular cutting edge 46. [0027] The punch 44 is applied at spaced intervals around a frame and afterward a cover strip 46 is clipped into place as shown in Figure 5. [0028] It will be appreciated that the channel 21 need only serve to locate, and the present invention can be used without deformation of the channel walls, it only requires the deformation of the screen 7 with part of the frame operating as a die and the provision of an effective shoulder to lock the screen in place. An example of this is given in Figures 6 and 7 where there is an extruded frame member 47 where a punch 48 is shown being retracted after deforming the marginal edge at 49 as shown in Figure 6. The frame member 47 has a shallow channel 50, cavities 51 and 52 and gaps 53 and 54 between sections 55, 56 and 57. Prior to deformation, the insulating strip 15 and screen section 14 are located with end 58 in the channel 50. The punch has a ring section 59 so it punches a ring into the cavities 51 and 52 through the gaps 53 and 54. A cover strip 60 is used to finish the assembly. [0029] Figure 8 illustrates another embodiment whereby a frame 61 has a channel 62 shown in its deformed configuration in Figure 8. The frame section 61 includes a cavity 63 that takes the bulge 64. [0030] The previous embodiments show quite a large deformation of the screen but it will be appreciated that depending upon the application of the present invention and the number of times and spacing of the applied punch the amount of deformation may be quite minimal using a slight compression and minor fracture. [0031] This is shown in Figures 9-11 where a frame 65 similar to Figure 3 embodiment has a channel 66 having internal beading 67 so that a matching insulating strip 68 may slide axially into the channel. In the previous embodiments the strip can be inserted sideways. After the strip is inserted the marginal edge 14 of the screen is inserted and then punch 69 is applied to compress the channel 68. The compression of the walls 70 and 71 is facilitated by providing various parallel lines of weakness 72, 73, 74, 75, 76, 77, 78 and 79. The assembly is then completed using a cover strip 80. [0032] It will be appreciated in the preceding figures that a full punch through approach may be taken or simply by applying a press without punching a hole of any kind. In another embodiment a combined press and punch may be used and this is given by way of example in Figures 12 and 13 where a combined punch and press 81 engages a frame 82 having a channel 83 , a cavity 84 and lines of weakness, in this case, back-to-back pairs of grooves 85, 86 and 87. prior to application of the punch press 81 the channel 83 is fitted with a PVC insulator 88 around the marginal edge portion 89 of screen 90 as shown in Figure 12. The press punch 81 has a punch section aligned with the grooves 86 and the edge 92 of the press is aligned with the grooves 85. upon application of 8 the press a section of the wall 93 is displaced laterally out of the plane of the wall 93 and the screen and insulator is punched as shown at 94 in Figure 13. The frame 82 has a ribbed channel 95 and this receives a push fit cover strip 96 as finishing shown in Figure 13. [0033] Referring to Figures 14 and 15 there is illustrated in two sizes (like numerals illustrate like features) extrusions 97 and 98. Extrusion 97 is suited to a window whereas extrusion 98 might be used for a door. The extrusions include a hollow body portion 99 having a front face 100, a rear face 101, an outside wall 102 and an inner panel or screen receiver section 103. The receiver section 103 have a first channel 104 and second and third channels 105 and 106 extending along the inside wall of the first channel. The channels 105 and 106 are separated by an upstand or rib 107. The rib 107 has a trapezoidal section. The rib 107 has a narrow top edge or surface 108 and a relatively wide base 109. The top edge 108 is positioned about halfway between walls 110 and 111 and directly below the medial raised section 112 of upper wall 113. The medial raised section 112 has grooves or shoulders 114 and 115 which are generally centred on the middle of channels 105 and 106 respectively. Grooves 114 and 115 are set for alignment with a punch adapted to punch a pair of holes through the wall 113 and drive the punch down into channels 106 and 107. In this embodiment the arrangement is to minimise the distortion of wall 113 and cut clean holes and also maintain the cross-section of the balance of the extrusion. There are other variables which come into play which aida clean cut and depending upon the fill material in the channel 104 and the reactive force upward in response to the punch, the level of deformation around the holes may be minimised so that it is not noticeable in the finished frame. [0034] Referring now to Figures 16, 17 and 18 (some section lines have been omitted for clarity), these drawings illustrate the process for punching out the holes in a similar extrusion 116. In this case the channels 117 and 118 are wider than in Figure 14 and the dimensions are clearly slightly different. The punch 119 is U-shaped having a first hole punch 120 and a second hole punch 121 which together punch a pair of holes 122 and 123 as shown in Figure 20 on either side of rib 108. The hole punches have their entry edges 124 and 125 aligned with grooves 126 and 127 and the rib 128 is centred between the hole punch sections 120 and 121. The rib is shown in phantom in Figures 19 and 20. [0035] In Figures 16-18 a U-shaped PVC insert 130 is positioned about the marginal edge 131 region of a screen 132. In Figure 18 the deformed sections of the wall 133, the insert 130 and 9 screen 132 is shown generally at 134. As shown in Figure 20 a rounded region of deformation is generally formed as a marginal pressed area 134 around the two holes but confined a small area of the wall section 133. [0036] As illustrated in Figures 14 and 16 there is some variability in the dimensions of the various parts when compared to Figures 19-19. Another variable is the type of PVC insert 130 and if it is made harder or softer, the channels 117 or 118 made wider, or the rib 128 varied, the formation of the holes 122 and 123 can be optimised and deformation minimised by appropriate selection of these. [0037] Whilst the above has been given by way of illustrative example of the invention 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. In addition where expressions including, comprises, comprising and the like are used herein these should be taken as non-exhaustive and non-limiting meaning that extra features may be added to the combination referred to by these terms and still fall within the broad ambit and scope of the invention as set out in the appended claims.