AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant: Aluminium Extrusion and Distribution Pty Limited Invention Title: INTERCONNECTION OF A MULLION WITH A WINDOW FRAME OR DOOR FRAME OR LIKE FRAME The following statement is a full description of this invention, including the best method for performing it known to me/us: 2 INTERCONNECTION OF A MULLION WITH A WINDOW FRAME OR DOOR FRAME OR LIKE FRAME FIELD OF THE INVENTION 5 This invention relates to interconnection of a mullion to a window frame or a door frame or like frame. BACKGROUND ART Hitherto, mullions have been interconnected to a 10 window or door frame or like frame of extruded or roll formed metal by connecting either with the head and sill, or with the head and a transom, or with the sill, and the transom. The mullion is of extruded or roll formed metal and it is a requirement for aesthetic reasons that the 15 mullion has a finished joint appearance at the interconnection with the head, sill or transom. In other words, from the outermost weatherside exposed face of the window or door frame a finished joint with the mullion should appear neat. 20 Hitherto, it has been common to pop rivet or screw fix the mullion to transversely extending flanges of the respective head, sill or transom. Such fixing involves a time consuming manual operation. Once fixed, 25 the pop rivets or the heads of screws are clearly visible from the outermost weatherside exposed face of the frame and this tends to provide for an unsightly aesthetic appearance. OBJECT AND STATEMENTS OF THE INVENTION 30 The present invention has been devised to attempt to provide alternative fixing which in some cases may result in less labour content and which will provide for an improved aesthetic appearance. 35 According to a first broad aspect of the present invention there is provided a method of interconnecting one end of a mullion to a window or door frame or like 3 frame (hereinafter referred to as "window frame"), said mullion and said window frame being of extruded or roll formed frame material, said method comprising shaping the top or bottom end of the mullion to fit relative to a 5 head, sill or a transom of said window frame so an outermost weatherside exposed face of the mullion will appear as butt jointed therewith and so there is one or more free flanges that extend transversely inwardly of the outermost weatherside face at the one end of the mullion, 10 said one or more free flanges being positioned to align with at least an outer laterally extending flange of the respective head, sill or transom, providing at least one key socket aperture in at least one of the one or more free flanges at a position 15 proximate to a laterally extending flange of the respective head, sill or transom that will be aligned therewith when the mullion is interconnected with the head, sill or transom, providing a corresponding one or more 20 passageways in the outer laterally extending flange of the respective head, sill, or transom, said one or more passageways each also defining a laterally extending key part, inserting the one or more free flanges of the 25 mullion in the corresponding one or more passageways in the outer laterally extending flange of the respective one of the head, sill, or transom to position the mullion so the key socket aperture is in alignment with the key part, laterally displacing the mullion relative to the 30 head, sill, or transom so the key part passes into said key socket, and then, glazing the window frame so the glazing holds the mullion in the laterally displaced condition. 35 Preferably the one or more passageways each provides two keys that face each other so the mullion can be laterally displaced to the left or the right to 4 appropriately position the mullion laterally relative to the head, sill or transom. A window frame having a mullion interconnected 5 therewith by the above method is also included. BRIEF DESCRIPTION OF DRAWINGS In order that the invention can be more clearly ascertained reference will now be made to examples of 10 preferred embodiments with reference to the accompanying drawings wherein: Figure la is a perspective view from an outermost weatherside face of the window frame or door frame 15 (hereinafter called "window frame") and showing a close-up view of interconnection of the mullion with the head, sill, and transom, Figure lb is a view similar to that shown in 20 Figures la but from the innermost non-weatherside face of the frame, Figure 2 is a side elevation view showing fitting of an upper and lower mullion to a transom, 25 Figure 3 is an exploded perspective view showing interconnection of an upper mullion and a lower mullion to a transom taken from the outside weatherside face of the frame, 30 Figure 4 is an exploded side elevation view of the arrangement shown in Figure 2, Figure 5 is a close-up isometric view showing an 35 upper mullion interconnected with a transom, Figure 6 is a close-up isometric view taken from 5 the non-weatherside face of the frame showing the mullion in position with the transom, and displaced laterally opposite to that shown in Figure 5, 5 Figure 7 is a plan view of the mullion interconnected with the transom, Figure 8 is a close-up isometric view from the right hand side, but otherwise of the same arrangement as 10 shown in Figure 6, and Figure 9 is an isometric view taken from the weatherside face of the frame, and showing glazing provided in glazing channels. 15 DETAILED DESCRIPTION OF PREFERRED EMOBODIMENT Referring to the example in Figures 1 - 9, there is shown detail of connection of a mullion to a head, a sill and a transom of a window frame or door frame 20 (hereinafter referred to as window frame). The jamb sections have not been shown as these are standard. The window frame includes a head 1, a sill 3, and a transom 5, all extrusion formed from metal such as aluminium. The particular cross sectional profile of the head 1, sill 3 25 and transom 5 may be formed in alternative ways such as by roll forming. In the case of roll forming, the transverse cross sectional profile will be slightly different owing to the roll forming process, but the concepts of the invention apply equally as well and are to be included 30 within the scope of the invention. Each of the head 1 and the sill 3 are provided with respective glazing channels 7 and 9 defined by laterally extending flanges 11 and 13. The transom 5 is provided with two glazing channels 15 and 17 formed by laterally extending flanges 19 and 21. Each 35 of the glazing channels 7, 9, 15 and 17 are vertically aligned with one another and have identical transverse cross sectional widths. The channels 7, 9 and 15 have 6 similar depths whereas channel 17 has a similar depth but the uppermost part of the channel 17 is angularly inclined downwardly. 5 Figure la shows a view from the outermost weatherside exposed face of the frame, whereas Figure lb shows a view from the innermost non-weatherside exposed face of the frame. Accordingly, when viewing Figure la, it can be seen that a mullion 23, in the form of an upper 10 mullion 23 and a lower mullion 23 extends between the head 1 and the transom 5, and the transom 5 and the sill 3. The cross sectional profiles of the upper transom 23 and the lower transom 23 are identical, except that the upper transom has a flange extension 24 to locate with a sliding 15 sash window frame that can slide laterally from side to side within the window frame, in a known manner. The sliding sash traverses in a sash channel 26. The top and bottom ends of each of the upper and lower mullions 23 are shaped to fit relative to the respective head 1, sill 3 20 and transom 5 so an outermost weatherside exposed face will appear as a finished joint therewith. Figure la clearly shows the finished butt joint arrangement. It is noted that the head 1 has a lower shallow step 25, the sill 3 has an upper shallow step 27, and the transom 5 has 25 a upper shallow step 29 and a lower shallow step 31. An outermost weatherside face 33 of the mullions 23 is arranged to align coplanar with a corresponding outermost weather face 35, of the head 1, sill 3, and transom 5. Figure la shows that for the transom 5 there are two 30 outermost weather faces 35, one being at the lower part of the transom, and being an extension of the downwardly inclined top of the glazing channel 17 adjacent the lower glazing channel 17. The other is adjacent the upper glazing channel 15. The outermost weather face 35 of the 35 sill 3 is a bead edge opposite glazing channel 9. The outermost weather face of the head 1, is opposite glazing channel 7. In each case, the outermost weather face 33 of 7 the mullion 23 fits flush with the corresponding outermost weather face 35 on the head 1, sill 3 and transom 5. Each end of the mullion 23 is therefore 5 appropriately shaped/profiled to enable this finished joint appearance to occur, and to provide one or more free flanges 41 that extend transversely inwardly of the outermost weatherside face of the mullion 23. Only one free flange 41 is shown in the example, although multiple 10 free flanges 41 could be provided. The free flange 41 is not clearly shown in Figure la or Figure lb but is shown in other figures such as in Figures 3 - 6. All free flanges 41 are arranged to align with an outer laterally extending flange 11, 13, 19 or 21, of the glazing channels 15 7, 9, 15 or 17. Figure 4 shows that the mullion 23 has a profile at an end that includes at least one key socket 45 in the at least one or more free flanges 41. The key socket 45 20 is, in this case, a rectangular shaped aperture and the key socket is cut to be substantially flush with the inside face of the flange 47 that forms the rear face of the outermost weatherside exposed face 33. The key socket 45 is set back from the extreme end of the mullion 23 at a 25 distance which will align with the inside face of the laterally extending flange 19 of the transom 5. Figure 3 in particular, shows one or more passageways 49 in the outer laterally extending flange 19. The number of passageways 49 corresponds with the number of laterally 30 extending flanges 41 on the mullion. In this case, the mullion has only one of these flanges 41 and therefore only one passageway 49 is provided. It can therefore be appreciated that the at least one key socket 45 is provided in the one or more free flanges 41 at a position 35 proximate to the aligned laterally extending flange 19 of the respective head 1, sill 3, or transom 5. It should be appreciated that the detail of connection at the head 1, 8 or sill 3 has not been shown. The connections to the head 1 and sill 3 are by an identical arrangement. In other words, the end of the mullion 23 to connect with the head 1 is correspondingly shaped to the end of the mullion 23 5 that connects with the transom 5. Similarly, the end of the mullion 23 that connects with the sill is similarly shaped. Figure 4 clearly shows a cut-out 51 at the extreme innermost edge of flange 41. The cut-out 51 is aligned with the aperture 45 laterally from the end of the 10 mullion 23 and is arranged to accommodate ribs 53 that are provided on the inside face of the channel 15 on laterally extending flange 21. This is best shown in Figure 5. The cut-out 51 provides a locating surface 55 (see Figure 4) that locates under the rib 53 which is lowermost in the 15 glazing channel 17. This is best shown in Figure 2. Thus, when the mullion 23 is fitted to the transom 5, it is moved so that the free flange 41 passes through the passageway 49 and so the locating surface 55 locates under the lowermost rib 53. This positions the mullion 23 and 20 provides the key socket 45 inwardly of the exposed weatherside face 33 of the transom 5. Figure 3 best shows that the passageway 49 has a lower part 59 that is somewhat enlarged relative to the 25 width of the passageway 49. Here, the part 59 is of rectangular configuration and the passageway 49, being slot shaped in this example, is situated midway along the length of the rectangular shaped opening of that part 59. This provides a laterally extending key part 61 on each 30 side of the passageway 49. In this example, the arrangement enables the upper mullion 23 to be inverted so that the flange extension 24 can be facing the opposite direction in order to receive an oppositely sliding sash window and to appropriately lock therewith. Thus, when 35 the mullion 23 is inserted through the passageway 49 it can be laterally displaced to one of the two ends and engaged with an opposite end of the part 59. If the sash 9 is an opposite hand sliding sash, then the mullion 23 can be inverted and slid to the opposite end of the part 59. One of the key parts 61 can then slide into the key socket 45, and hold the mullion against vertical up and down 5 displacement relative to the transom 5. Once both ends of the mullion 23 have been fixed to the respective head and transom, and transom and sill, or head and sill then in order to hold the mullion 23 in 10 the correct lateral position, glazing is provided in the glazing channels, as shown in Figure 9. This prevents the mullion 23 from being displaced laterally. Modification may be made to the invention as 15 would be apparent to persons skilled in the art of producing window frames and/or door frames or like frames. For example, the sections need not be extruded or roll formed aluminium but may be extruded plastics material or other appropriately shaped materials. The concepts 20 outlined above apply to all of the types of frame members. In addition instead of glazing the window frame to hold the mullion in the laterally displaced position the window frame may be filled with a filling such as a 25 sheet of plasterboard or other sheet like material. It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part 30 of the common general knowledge in the art, in Australia or any other country. In the claims which follow and in the preceding description of the invention, except where the context 35 requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, 10 i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.