AU2005200210B2

AU2005200210B2 - Bi-fold door assembly

Info

Publication number: AU2005200210B2
Application number: AU2005200210A
Authority: AU
Inventors: Ross Lloyd
Original assignee: Aluminium Extrusion and Distribution Pty Ltd
Current assignee: Aluminium Extrusion and Distribution Pty Ltd
Priority date: 2004-02-02
Filing date: 2005-01-17
Publication date: 2011-05-19
Anticipated expiration: 2025-01-17
Also published as: NZ537940A; AU2005200210A1

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): CRANE ENFIELD METALS PTY LTD A.C.N. 008 408 151 Invention Title: BI-FOLD DOOR ASSEMBLY The following statement is a full description of this invention, including the best method of performing it known to me/us: - 2 BI-FOLD DOOR ASSEMBLY FIELD OF THE INVENTION 5 This invention relates to a bi-fold door assembly and relates particularly, but not exclusively to a bi-fold door assembly that may be used to close openings in buildings that are larger than a single door in width. 10 BACKGROUND ART Hitherto, bi-fold door assemblies have been used to close openings in buildings. The openings may be internal wall openings, or external wall openings where the door is 15 subject to exposure to weather. In recent times cafes, in particular, have utilised bi-fold door assemblies to close or open the front of the caf4 to the public. This allows a caf6 to have tables in the open air outside of the building of the caf4 and enables the patrons to feel that 20 they are still part of the caf4 . In homes, bi-fold doors have been used to close internal wall openings, or external wall openings where a person can open the bi-fold door assembly to give the feeling of open space to the building. As the opening usually extends over a 25 considerable length, it means that a plurality of bi-fold door panels need to be hinged together and suitably carried. The bi-fold door assemblies are suspended from an upper track and carried by one or more wheels at the top of the door panels which engage and suspend the door 30 panels from a head part of a door frame in which the track is located. Typically, the weight of the door panels is excessive and there needs to be structural lintels or other structural arrangements provided to accommodate for the weight of the door panels. In some instances, the 35 bottom of the door panels can be guided by a wheel which traverses along the floor but in all instances the bulk of H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 -3 the weight of the door panels is carried by the upper track. As there needs to be a lintel provided of sufficient 5 structural strength to accommodate the weight of the door panels it generally means that retro fitting of a bi-fold door assembly in a door opening is limited to purpose built openings. If a lintel is not provided, then a bi fold door arrangement cannot be accommodated. 10 Accordingly, for renovators wishing to modernise a caf4 or home and provide a bi-fold door arrangement there has generally been an obstacle to the installation of a bi fold door assembly. Further, even if a lintel is provided, the weight of the door panels is usually of such 15 magnitude that there is sagging of the lintel over a period of time and the bi-fold door assembly needs to receive constant adjustments of the suspension mechanism to maintain the bi-fold door assembly tracking correctly during opening and closing movement. 20 STATEMENT OF THE INVENTION Accordingly, there is a need for a different bi-fold door assembly. 25 According to one aspect of the invention there is provided a bi-fold door assembly having at least a sill and two door panels that are bi-foldable, said sill having a track extending in a direction along the length of the 30 sill and on which a weight bearing surface supporting at least one of the door panels is received so said weight bearing surface will track along the track during opening and closing of the door panels and carry the bulk of the weight of the at least one door panel on said track, 35 wherein when the at least two door panels are in an 2609752_1 (GHMaItr) P50283.AU 1 -3a assembly closed condition said track is substantially wholly under the door panels and the track is provided in a cavity in said sill below an upper surface of said sill, wherein the weight bearing surface is held captive within 5 the cavity, the upper surface of the sill having an elongate opening through which a connection means connecting said weight bearing surface to said at least one door panel can pass. 2600752_1 (GHMatter) P50283 ALII -4 Most preferably the door panels are hinged together and wherein one of the door panels is hinged to an upright door frame part of the assembly, or to an upright wall of 5 an opening in which the bi-fold door assembly is installed, and wherein the axis of swinging is about an upright axis, and wherein the other door panel is hinged to the one door panel to swing about a further upright axis. 10 Most preferably said track is provided in a cavity in said sill below an upper surface of said sill, and wherein said track is displaced to an inside side of said sill or to an outside side of sill relative to a longitudinal 15 extent of said sill. Most preferably said displacement is relative to an elongate opening in an upper surface of said sill that communicates with said cavity and through which a 20 connection means can pass, said connection means connecting said weight bearing surface to said at least one door panel. Most preferably there are two parallel tracks in 25 said cavity with one being on an inside side, and the other being on an outside side relative to a longitudinal extent of said sill, and wherein said connection means carries two weight bearing surfaces, one weight bearing surface engaging one 30 of the tracks and the other weight bearing surface engaging the other of the tracks. Most preferably said connection means connects with a door panel at a position proximate to a side edge of a 35 door panel on the opposite side to said further upright axis. H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 5 Most preferably said track is upstanding from a bottom of said cavity and is at least partly shielded from debris that may pass through said elongate opening by an upper surface of said sill. 5 Most preferably said connection means connects with a side thrust bearing surface that, in turn, co-operates with a corresponding side thrust bearing surface carried by said sill, said side thrust bearing surface being for 10 inhibiting angular inclination of the door panels from an intended upright condition otherwise caused by the weight of the door panels cranking the door panels from an intended upright condition, said side thrust bearing surface being engageable 15 with a corresponding side thrust bearing surface carried by said sill. Most preferably said connection means is connected with a trolley. 20 Most preferably the weight bearing surface is two weight bearing surface means spaced so one is on an inside side and the other is on an outside side of said trolley relative to said sill. 25 In one embodiment the weight bearing surface is wheel means. In another embodiment the weight bearing surface may 30 be a slide surface for engaging with a corresponding slide surface of said track. It is particularly preferred that the track is a rib or flange that extends in a direction longitudinally of 35 the cavity. H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 -6 It is particularly preferred that the weight bearing surface be shaped to laterally locate with the track so there will be aligned tracking as the bi-fold door panels are opened and closed. 5 Most preferably the trolley carries an upright connection arm as the connection means to make connection with at least one of the door panels, and wherein the connection to the at least one of the panels is such that 10 substantially the whole width of each panel swings either to the inside side of the assembly, or the outside side of the assembly during opening of the door panels. Most preferably said trolley is elongate in a 15 direction along the track and where the weight bearing surface includes an inside side pair of wheels and an outside side pair of wheels relative to said sill and wherein the inside side pair of wheels locates on a common rib or flange of said track, and wherein the outside side 20 pair of wheels locates on a further common rib or flange of said track. Most preferably the wheels are grooved so that the respective common ribs or flanges are received within the 25 grooves to assist tracking of the carriage. Most preferably said side thrust bearing surface carried by said sill is a still further rib or flange extending from said sill. 30 Most preferably said side thrust bearing surface is wheel means. Most preferably said wheel means for side thrust 35 bearing is one of the pair of wheels and wherein the weight bearing surface is diametrically opposite the side thrust bearing surface across said pair of wheels. H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 -7 In one embodiment said side thrust bearing surface carried by the sill is two side thrust bearing surfaces, so that one surface inhibits anti-clockwise angular 5 inclination and the other surface inhibits clockwise angular inclination, caused by the weight of the door panels cranking the door panels from an intended upright condition. 10 Most preferably the door panels are guided relative to a head of the assembly by a head tracking means that extends between the top of the door panels and said head. Most preferably the head tracking means is a finger 15 connected to and extending in a direction upwardly from the top of at least one of the door panels and wherein said finger locates in an elongate cavity in said head and wherein said cavity defines a head track in which said finger can traverse in a direction that extends along the 20 longitudinal extent of the head. Most preferably said finger carries a wheel that can rotate about an upright axis and wherein the wheel locates in said cavity and acts to guide the top of at least one 25 of door panels as the door panels are opened and closed. Most preferably the sill is a two part sill with a first part defining a part of the outside side of said cavity, the second part defining a part of the inside side 30 of said cavity, and wherein the first part and the second part are connectable and collectively define the sill and the cavity, and wherein the trolley can be inserted or removed from the cavity by disconnecting or reconnecting the first part and the second part, and wherein when the 35 first part and second parts are reconnected the trolley is held captive within the cavity in the sill but able to traverse in said cavity in said direction. H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 8 Most preferably the first part and the second part are provided with co-operating snap lock fitting surfaces that permit snap lock engagement or disengagement of the first part and the second part for the connection and 5 disconnection of the first part and the second part. BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention can be more clearly 10 ascertained an example of preferred embodiment will now be described with reference to the accompanying drawings wherein: Figure 1 is a front isometric view of a typical 15 example of a preferred embodiment of a bi-fold door assembly, Figure 2 is a close up perspective, part sectional view from an inside side of the assembly shown in Figure 1 20 showing a sill trolley fitted in the sill, Figure 3 is a top perspective view of the sill trolley shown in the example, 25 Figure 4 is an exploded perspective view of the sill trolley and a hinge that connects with door panels, Figure 5 is a non-exploded view similar to that of Figure 4 and showing door panels in a partly open 30 condition, Figure 6 is a perspective view of a hinge for fitting at the top of a pair of door panels, showing the hinge in a closed condition, 35 Figure 7 is a view similar to that of Figure 6, but showing the hinges in a door open condition, 2609752_1 (GHMatters) P50283 AU I 9 THIS PAGE IS LEFT INTENTIONALLY BLANK 2609752_1 (GHMaW s) P50283.AU I - 10 Figure 8 is a view similar to that of Figures 6 and 7, but showing the hinge at the top of the door panels in partly opened condition and fitted to door panels, 5 Figure 9 is a plan view, in section, at a lower-most part of pair of door panels, showing the door panels in a closed condition, 10 Figure 10 is a view similar to that of Figure 9, but showing the door panels in an open condition, Figure 11 is a vertical cross-sectional view showing the relationship of the door panels to the sill and the 15 head, Figure 12 is a transverse cross sectional view of the sill and, 20 Figure 13 is a diagramatic vertical cross sectional view showing a different example of a sill. DETAILED DESCRIPTION OF EXAMPLES 25 Referring firstly to Figure 1, there is shown a bi fold door assembly 1 made from extruded aluminium sections. Whilst extruded aluminium sections are preferred, other materials such as wood, steel and the like may be used. The invention is not to be limited to 30 extruded aluminium sections. The assembly comprises an outer frame that fits in an opening in the building. The outer frame is formed by a head 3, a sill 5, and 2 upright door frame parts 7. The upright door frame parts 7 have been shown as this is preferred. In some installations, 35 the upright door frame parts 7 may not be utilised but instead, the inside upright walls of the opening may define the outer side edges of the opening and the H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 11 assembly. Figure 1 shows the assembly viewed from an outside side of an installation. Here it can be seen that the sill 5 has a downwardly sloping forward part which is provided for aesthetic reasons and also to inhibit against 5 the likelihood of a person tripping across the sill as they pass through the assembly when it is opened. In the assembly shown there are three door panels 9. The door panels 9 are made from extruded aluminium sections and interconnected by hinges. They may be made from other 10 materials such as wood or steel as described previously without departing from the ambit of the invention. The panels themselves in each of the door panels 9 may be glass or other planar structural material. One of the door panels 9 is hinged about an upright axis to one of 15 the upright door frame parts 7. Alternatively, it may be hinged to swing about an upright axis by being hinged directly to an upright part of the opening in a wall in the building. The other panels are hinged about a further upright axis at a side opposite. 20 In the arrangement shown, the door panels are hinged by suitable hinges (to be referred to later). Typically, three hinges are provided at each of the hinge axis. The exact number of hinges and the type of hinges can be 25 chosen according to the size and weight of each of the door panels 9 and/or hinging arrangement required by the individual requiring the bi-fold door assembly. Figure 2 shows a close-up perspective part cross 30 sectional view of the sill 5. A trolley 11 is provided to carry a weight bearing surface 13 (in this example wheel means) and the trolley, in turn, supports the bulk of the weight of at least one of the door panels. The trolley 11 can track along the sill along a track 15 provided on the 35 sill. The track 15 extends in a direction along the length of the sill. Accordingly, during opening and closing of the door panels 9, the trolley 11 will support H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 12 the bulk of the weight of at least one of the door panels 9 by the weight bearing surface 13 engaging on the track 15 and so the track 15 supports the weight of the door panels 9. The track is substantially wholly under the 5 door panels, when the door panels assume a closed condition in the assembly. This assists in inhibiting debris from entering the sill and fouling the track, thereby preventing good movement of the trolley 11 along the track 15. 10 The weight bearing surface 13 may be provided by a slide surface, such as of a suitable plastics material slide surface fitted to the trolley. 15 In the embodiment shown, where there are three door panels 9, only one trolley 11 is required. In other installations, where there are multiples of the door panels 9, two or more trolleys 11 may be required. The trolley 11 has a connection means 17 that enables the 20 panels 9 to be connected with the trolley 11 at suitable positions such as, in this example, at a hinge of the panels. In the arrangement shown, and in Figure 1, the connection is at the hinge positions between the outermost free door panel 9 and the next adjacent door panel 9. i.e. 25 the end opposite to the end at which the door panels 9 are hinged to the upright door frame part 7 or to the wall of the building. The trolley 11 is received within a cavity 19 in the 30 sill 5. The cavity 19 is not clearly shown in Figure 2 but will be explained further in relation to Figures 11 and 12 in due course. Accordingly, the track 15 is at the bottom of the cavity 19. The connection means 17 passes through an opening 21 in an upper surface of the sill 5 35 and permits connection between the trolley 11 and the door panels 9. The opening 21 extends along the longitudinal extent of the sill 5. Figure 2 clearly shows that there H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 13 are two tracks 15 at the bottom of the cavity 19. As shown, there are a pair of wheels on an inside side of the trolley 11 and further pair of wheels on an outside side of the trolley 11. This is more clearly shown in Figure 5 3. Each of the wheels of the trolley has a weight bearing surface 13 and one pair of wheels tracks on one of the tracks 15 whilst the other pair of wheels tracks on the other track 15. It can be seen that the weight bearing surfaces 13 are grooved so that they are shaped to 10 laterally locate with the tracks so there will be aligned tracking as the bi-fold door panels are opened and closed. Each of the tracks 15 is an upstanding rib or flange from the bottom of the cavity 19. 15 The trolley 11 also carries a side thrust bearing surface 23. This side thrust bearing surface 23 co operates with a corresponding side thrust bearing surface 25 on the sill to inhibit angular inclination of the door panels from an intended upright condition otherwise caused 20 by the weight of the door panels cranking the door panels from an intended upright condition. This is not clearly shown in Figure 2, but will be explained in more detail hereinafter in relation to Figure 11. Preferably, the side thrust bearing surface 25 on the sill is a rib or 25 flange that extends downwardly from an upper surface of the sill. In a particularly preferred example of the embodiment, as shown in the figures herein, the side thrust bearing surface 23 of the trolley is on the opposite side of wheels relative to the weight bearing 30 surface 13, and is on one of the pair of wheels. Typically, the side thrust bearing surface 25 of the sill is provided within the cavity 19 on an under surface of an upper part of the sill that partly defines the cavity 19 but it may be on upright side walls or on a rib or 35 flange that extends therefrom. H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 14 Accordingly, it can be seen from Figures 2 and 3 that the trolley 11 is elongate in a direction along the longitudinal extent of the sill 5. The body of the trolley 11 may be made from any suitable material such as 5 industrial grade plastics or die cast metals. The trolley has a side 27 which is intended for fitting to an outside side of the assembly. It also has an inside side 29 for fitting to an inside side of the assembly. In Figure 2 the outside side is the side shown facing the viewer 10 whilst the inside side is the opposite side. The weight bearing surfaces 13 are provided by a pair of wheels on each of the outside side 27 and the inside side 29. The wheels are identified by numeral 31. Each wheel 31 contains bearings 33 that permit the wheels to rotate 15 about axles 35 that are fixed relative to the trolley 11. Typically the wheels 31 are made from an industrial grade plastics and are grooved as shown to assist in tracking along the upstanding ribs or flanges that define the tracks 15. Typically, the side thrust bearing surface 23 20 does not directly touch the side thrust bearing surface 25 of the sill until there is cranking of the trolley caused by the weight of the door panels. The tolerance between the side thrust bearing surface 23 of the trolley and the corresponding side thrust bearing surface 25 of the sill 25 can be a small dimension such as 1mm. Accordingly, if the trolley should be cranked because of the weight of the door panels when the door panels 9 are opened, then when the side thrust bearing surfaces 23 of the trolley engage with the side thrust bearing surfaces 25 of the sill, the 30 weight bearing surface 13 on the opposite side of the wheels disengages and lifts off the track 15 in the sill. Of course, the weight bearing surface 15 of the other pair of wheels 31 remains engaged on the track 15 for those pair of wheels. This will be explained further in due 35 course. 2609752_1 (GHMatters) P50283.AU I - 15 The connection means 17 carried by the trolley 11 has a height adjustment means 38 in the form of two nuts that are screw threaded relative to the connection means 17. Accordingly, by appropriately adjusting the nuts, and re 5 tightening them, there can be adjustment of the spacing between the bottom surface of the door panels and the upper surface of the sill. Whilst the side thrust bearing surface 23 of the 10 trolley is shown as being the wheels 31, it may be provided by either slide surface of surfaces such as of a suitable plastics material, or a further wheel or wheels. If a separate side thrust bearing surface 23 is provided independent of the wheels 31, then a closer tolerance 15 between the side thrust bearing surface 23 and the side thrust bearing surface 25 may be provided. Referring now to Figures 4 and 5, there is shown how the weight bearing surfaces 13 are connected via the 20 connection means 17 to the door panels. In the preferred example, the connection is directly at the hinges 37 that hinge the door panels together. Figure 4 clearly shows the wings 39 of the hinges 37. The wings are preferably made from a suitable material such as brass, aluminium or 25 the like. The wings 39 have a fixing flange part 41 with a number of openings therein through which screws can be passed to fix the door panels 9 thereto. Connected with the fixing flange part 41 is an offset flange part 43, and connected with the offset flange part 43 is a further 30 offset part 45 that has cylindrical hinge pin collars 47 attached to a free side thereof. Each of the offset flange parts 43 is stepped inwardly from the top and bottom edges of the fixing flange part 41 as shown. The spacing between the collars 47 is such that when the wings 35 39 are brought together, all the collars 47 will between one another and align centrally so that a hinge pin 49 can be passed therethrough to hinge the wings 39 together. H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 16 Spacing washers or bushes may be provided between the adjacent collars 47 if required. Figures 4 and 5 also show a yoke 51 that forms a connection between the connecting means 17 and the door panels. The yoke 51 is 5 made from a suitable material such as brass and has a first body 53 of elongate cylindrical construction. Connected to the first body 53 are two arms 55, and at the free end of arms 55 collars 57. The collars 57 have the same shape and size as the collars 47. The spacing apart 10 of the arms 55 and the collars 57 from each other is such that the arms 55 straddle the top and bottom of the hinge collars 47. Accordingly, the hinge pin 49 can hold the hinges 37 via the yoke 51 to the connection means 17. The central bore of the first body 53 is of a size to closely 15 fit over the circular cross-section connection means 17. To minimise any relative rotation of the yoke 51 about the connection means 17, the connection means 17 has a laterally fitted pin 59 that passes into an opening 61, and the pin 59 is arranged to locate in a keyway slot 63 20 in the bore of the first body 53. Accordingly, the arms 55 of the yoke 51 are held in a direction perpendicular to the longitudinal extent of the sill as the pin 59 inhibits rotation of the yoke 51 relative to the connection means 17. Plugs 65 can be used to close any spaces at the top 25 and bottom of the hinges. The yoke 51 can be held captive to the connecting means 17 by means of a screw and washer arrangement as shown. Accordingly, it can be seen that the connection means 17 connects with a door panel 9 at a position proximate to a side edge of a door panel 9 on the 30 opposite side to the further upright axis (i.e. generally at the hinge axis). Figure 5 shows that the frames of the door panels 9 are suitably checked with cut-outs 69. This maintains the 35 collars 47 and 57 closely fitting relative to the faces of the door panels 9. The spacing of the arms 55 is such that the first body 53 of the yoke 51 is displaced to the H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 17 opposite side of the door panels 9 and allows for closing of the door panels so that the yoke of the first body 53 is concealed within cavities 71 of the frames of the door panels 9 when the door panels 9 are in a closed condition 5 (the hinges are closed). The offset flange parts 43 also have a sufficient dimension to enable the first body 53 of the yoke 51 to be held between the wings of the hinges 37 when the door panels 9 are in a closed condition. 10 Figure 8 clearly shows how the first body 53 of the yoke 51 locates in the cavities 71 of the frames of the door panels 9. The hinges at an intermediate height of the door 15 panels 9 comprise hinges 37 without yokes 51. The hinges at the top of the door panel are hinges of a similar construction to that shown and explained for the bottom of the door panel and also include the same yoke 51. This arrangement is shown in Figures 6, 7 and 8. For these 20 upper hinges, the first body part 53 carries an upstanding pin 73. The pin is not clearly visible in the figures and has not been numbered. The pin has a collar part 75 that is fitted adjacent the upper surface of the first body 53. Affixed above the collar 75 is a wheel 77 of slightly 25 larger diameter than the diameter of the collar 75. The spacing between the collar 75 and the wheel 77 is sufficient to accommodate the thickness of flange parts that define side edges of a longitudinally extending head track cavity 79 in the head 3. Accordingly, the wheel 77 30 locates within the track cavity 79 and an outer surface of the wheel engages with the inside side or the outside side of walls 81 of the cavity. Accordingly, this acts to provide a guide for the upper part of the door panels. This guide is therefore for also inhibiting against 35 angular cranking of the door panels from an intended upright position during opening and closing movement. Whether the wheel 77 engages with the walls 81 is not H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 18 entirely critical to the operation of the guiding for holding the upper part of the door panels 9 in an intended upright position as the side thrust bearing surface 23 is intended to provide the primary means to inhibit against 5 cranking. Accordingly, the track cavity 79 and the pin 73, collar 75, wheel 77 and walls 81 define a head tracking means in the form of a finger that extends upwardly from the top of at least one of the door panels. The cavity 79 defines a head track in which the finger can 10 traverse in a direction that extends along the longitudinal extent of the head. The wheel 77 can rotate about an upright axis and the wheel 77 locates in the cavity and acts to guide the top of at least one of the door panels as the door panels are opened and closed. 15 Referring now to Figures 9 and 10 there are shown transverse cross-sectional views immediately above the trolley 11 and taken horizontally through the door panels 9. Figures 9 and 10 also clearly show how the collars 47, 20 57 fit closely and snugly against one face of the door panels 9. The figures also show how the arms 55 of the yoke pass between the adjacent outer side edges of the door panels 9 when the door panels 9 are closed. The figures also show how the first body 53 of the yoke 51 25 fits within the cavity 71 in the door panels 9 and between the wings of the hinges. Referring now to Figure 11 there is shown a vertical cross-sectional view of the door assembly 1, in a door 30 closed condition. Figure 11 also clearly shows the outside side 27 of the assembly and the inside side 29 of the assembly. It also shows the weight bearing surfaces 23 engaging with the two tracks 15 and carrying the bulk of the weight of at least one of the doors panels 9. 35 Figure 11 also shows that the upper part of the door panels 9 are guided relative to the head 3 by a head tracking means by a finger connected to and extending in a H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 19 direction upwardly from the top of at least one of the door panels 9 and wherein the finger locates in an elongate cavity in the head 3. The figure also shows that the cavity 3 defines a head track in which the finger can 5 traverse in a direction that extends along the longitudinal extent of the head. The finger is therefore comprised of the pin 73, collar 75 and wheel 77. In the arrangement shown, when the doors open, the door panels 9 swing to the outside side 27 of the assembly. Thus, the 10 weight of the doors is offset from the weight bearing surface 13, and tends to crank the doors from an intended upright condition in a generally anti clockwise direction (when viewing Figure 11). This tends to lift the right hand side weight bearing surface 13 off the track 15 and 15 causes the side thrust bearing surface 23 to engage with the side thrust bearing surface 25 of the sill. The side thrust bearing surface 23 of the trolley has not been identified in Figure 11 in order to aid clarity. 20 Figure 11 also shows that the pair of tracks 15 are at the bottom of the cavity 19 and elevated from the bottom. It also shows that each of the tracks 15 is partly shielded from debris that may pass through the elongate opening 21 (numerically identified only in Figure 25 2 in order to aid clarity), and therefore the tracks 15 remain substantially free of debris. From time to time, the cavity 19 may need to be opened. This may be undertaken to replace a trolley and 30 its respective wheels 31 or alternatively to remove debris from the cavity 19. Figure 12 shows how the sill 5 is at least a two part sill with a first part 83 defining a part of an inside 35 side of the elongate sill cavity 19 and a second part 85 that defines a part of the outside side of the cavity 19. Figure 12 shows that the first part 83 and second part 85 H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 20 are connectable together and collectively define the sill and the cavity 19 in which the trolley 11 can be received to carry the bulk of the weight of at least one of the door panels 9 of the assembly. Accordingly, by 5 disconnecting the second part 85 from the first part 83, the cavity 19 may be opened to enable insertion and/or withdrawal of a trolley with associated wheels 31. The grooves in the wheels 31 have sufficient height and clearance to enable the wheels 31 to appropriately locate 10 on the relevant tracks 15 and the side thrust bearing surface 25. Debris may also be removed from the cavity 19 when the first part 85 is disconnected from the first part 83. The example shows that the first part 83 is provided with snap lock engaging ribs 87, and that the second part 15 85 is provided with complementary snap lock engaging ribs 89. Accordingly, by appropriately manipulating the second part 85 relative to the first part 83, there can be connection and/or disconnection of the first and second parts, and opening and/or closing of the cavity 19. 20 While snap lock engaging and disengaging has been shown, other forms of connection such as screw fastening may be provided. Figure 12 shows a slightly different sill to that shown in Figure 11. In Figure 12, there is 25 no foot tread 91 of wood or the like that forms a structural or finishing part of the opening in the building as shown in Figure 11. Instead, the sill 5 has a snap lock engageable base part 93 that can be fitted to the first part 83. This arrangement may be provided for 30 installations where there is no tread 91. Returning now to Figure 1, it can be seen that some of the door panels 9 have been shown with handles 95. The handles 95 are connected internally of the door frames. 35 with cranking arms that extend rods 97 either inwardly or outwardly relative to the upper and lower surfaces of the frames of the door panels 9. The rods 97 are arranged to H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 21 locate between the opening 21 in the sill 5, and the corresponding opening in the cavity 71 in the head 3. In this way, when the door panels 9 lie in line and parallel to one another, the door panels can be locked closed by 5 appropriately rotating the handles 95. Modifications may be made to the invention as would be apparent to persons skilled in the art of making doors and in particular bi-fold doors. For example, instead of 10 the connecting means 17 being circular in transverse cross-section it may be rectangular or of other suitable cross-section and arranged to fit into a corresponding rectangular opening in the first body 53 of the yoke 51. In this way, the keyway slot 63 and corresponding pin 59 15 may be dispensed with because if the connecting means 17 is rectangular or if other suitable cross section and fits in a corresponding opening in the body 53, the yoke will be held generally perpendicular to the tracks 15 without relative rotation. Other cross sectional profiles may be 20 adopted to provide the same effect. Whilst the weight bearing surfaces 13 have been shown as wheels 31, they may be slide surfaces formed from a suitable synthetic plastics material. Similarly, the side thrust bearing surfaces 23 may be replaced by corresponding slide 25 surfaces. Figure 11 shows that when the door panels 9 are closed, they close against door stops formed on the head 3, sill 5 and the upright jamb part 7. This provides an 30 effective weather seal particularly if suitable seal means 99 are provided. The provision of door stops is not an essential feature. Further, whilst the panels 9 have been shown hinged 35 to one another and to an upright door part 7 such as the wall or a jamb, the door panels may be hinged only to one another, but not to the upright door part 7. In other H:\Priyanka\Feep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 22 words, the door panels will be relatively free and constrained within the assembly by the tracks 15 in the sills and track cavity 79 in the head 3. When the door panels are fully closed and parallel to one another and 5 inline, the panels 9 will then close the opening. Operation of the handles 95 can then cause the rods 97 to extend outwardly and to lock into the respective openings will and that will hold the assembly locked closed. 10 Further, whilst the assembly has been shown with the door panels hinged to one another, the door panels may each be independent of each other without being hinged to one another, and wherein the connection means 17 connects at a position midway between the left and right hand sides 15 of each of the panels 9. In this arrangement, there would need to be relative rotation between the connecting means 17 and door panels 9 to allow for the angular rotation during opening and closing. Nevertheless, the arrangement of the side thrust bearing surfaces 23 and 25 would still 20 be provided to inhibit against cranking that may be caused during movement of the door panels. Accordingly, in this arrangement, when the door panels are fully closed, so that they lie parallel to one another and in line, the door panels may be arranged to interlock with each other 25 by appropriate tongue and grooves in the outer side edges. Accordingly, when the handles 95 are cranked, the rods 97 will then also hold the door panels 9 in a locked condition. 30 In a variation of the above the door panels 9 may be hinged to one another, and the connection means connect with one or more of the panels at a position midway between the left and right hand sides of the one or more panels. 35 Whilst a trolley 11 has been shown, the trolley itself may not be a physical trolley but merely an H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 23 extension of the connection means 17. In such instance the relevant part of the connection means 17 will be a trolley. 5 In the example shown in Figure 13 a further alternative arrangement is depicted. Here, the sill is similar to that shown in the previous figures except that there is an additional side thrust bearing surface 25. Accordingly, above one of the tracks 15 is a side thrust 10 bearing surface 25 and above the other of the tracks 15 there is a side thrust bearing surface 25. Under normal conditions when the trolley 11 carries the weight of the door panels without any clockwise or anti-clockwise cranking caused by the weight of the door panels, the 15 weight of the door panels is carried by the tracks 15. In this case, the upper surface of the wheels 31 is not touching the side thrust bearing surfaces 25. However, should there be clockwise or anti-clockwise cranking, the respective wheel 31 will lift off the respective track 15 20 and engage the side thrust bearing surface 25. Accordingly, the arrangement shown in Figure 13 will inhibit against clockwise or anti-clockwise cranking caused by the weight of the door panels. Whilst the side thrust bearing surfaces carried by the trolley 11 (the 25 upper surface of the wheels 31) are normally displaced a small distance such as 1mm from the side thrust bearing surfaces 25 they may be brought into respective engagement depending on the direction of cranking caused by the weight of the door panels. 30 Further, instead of utilising the wheels 31 to provide for the side thrust bearing surfaces 23 on the trolley, additional wheels may be provided to provide the side thrust bearing surfaces or alternatively there may be 35 corresponding slide surfaces provided to replace the wheels. H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05 - 24 These and other modifications may be made without departing from the ambit of the invention the nature of which is to be determined from the foregoing description. H:\Priyanka\Keep\speci\BI FOLD DOOR ASSEMBLY - CAP AU.doc 17/01/05

Claims

1. A bi-fold door assembly having at least a sill and 5 two door panels that are bi-foldable, said sill having a track extending in a direction along the length of the sill and on which a weight bearing surface supporting at least one of the door panels is received so said weight bearing surface will track along 10 the track during opening and closing of the door panels and carry the bulk of the weight of the at least one door panel on said track, wherein when the at least two door panels are in an assembly closed condition said track is substantially wholly under the door panels and the track 15 is provided in a cavity in said sill below an upper surface of said sill, wherein the weight bearing surface is held captive within the cavity, the upper surface of the sill having an elongate opening through which a connection means connecting said weight bearing surface to 20 said at least one door panel, can pass.

2. An assembly as claimed in claim 1, wherein said connection means connects with a side thrust bearing surface that, in turn, co-operates with a corresponding 25 side thrust bearing surface carried by said sill, said side thrust bearing surface being for inhibiting angular inclination of the door panels from an intended upright condition otherwise caused by the weight of the door panels cranking the door panels from an intended upright 30 condition.

3. An assembly as claimed in claim 1 or claim 2, wherein said track is displaced to an inside side of said sill or to an outside side of said sill relative to the elongate 35 opening. 2609752_ (GHMattcrs) P50283.AlU. I 21/03/11 26

4. An assembly as claimed in any one of the preceding claims, wherein there are two parallel tracks in said cavity with one being on an inside side, and the other 5 being on an outside side relative to the elongate opening of said sill, and wherein said connection means carries two weight bearing surfaces, one weight bearing surface engaging one of the tracks and the other weight bearing surface 10 engaging the other of the tracks.

5. An assembly as claimed in any one of the claims 3 to 5 when appended to claim 2, wherein said connection means connects with a door panel at a position proximate to a 15 side edge of a door panel on the opposite side to an upright axis about which two door panels are hinged and swing relative thereto.

6. An assembly as claimed in claim 5 or claim 6 when 20 appended to claim 4, wherein said track is upstanding from a bottom of said cavity and is at least partly shielded from debris that may pass through said elongate opening by an upper surface of said sill. 25

7. An assembly as claimed in any one of the preceding claims, wherein the weight bearing surface is two wheels mounted on a trolley to which the connection means is connected, the wheels being spaced so one is on an inside side and the other is on an outside side of said trolley 30 relative to said sill.

8. An assembly as claimed in any one of the preceding claims, wherein the track has a rib or flange that extends in a direction longitudinally of the cavity. 35

9. An assembly as claimed in any one of the preceding claims, wherein the weight bearing surface is shaped to 2609752_1 (GHMatters) P'50283.AU.1 21/03111 27 laterally locate with the track so there will be aligned tracking as the bi-fold door panels are opened and closed.

10. An assembly as claimed in claim 7, wherein said 5 trolley is elongate in a direction along the track and where the weight bearing surface includes an inside side pair of wheels and an outside side pair of wheels relative to said sill and wherein the inside side pair of wheels locates on a common rib or flange of said track, and 10 wherein the outside side pair of wheels locates on a further common rib or flange of said track.

11. An assembly as claimed in claim 10, wherein the wheels are grooved so that the respective common ribs or 15 flanges are received within the grooves to assist tracking of the carriage.

12. An assembly as claimed in claim 2, wherein said side thrust bearing surface carried by said sill is a rib or 20 flange extending from said sill.

13. An assembly as claimed in claim 19, wherein the side thrust bearing surface is a wheel means, said wheel means for side thrust bearing is one of the pair of wheels and 25 wherein the weight bearing surface is diametrically opposite the side thrust bearing surface across said pair of wheels.

14. An assembly as claimed in claim 13, wherein said side 30 thrust bearing surface carried by the sill is two side thrust bearing surfaces, so that one surface inhibits anti-clockwise angular inclination and the other surface inhibits clockwise angular inclination, caused by the weight of the door panels cranking the door panels from an 35 intended upright condition. 2609752_1( (GHMatters) P50283.AU. I 21/03/11 28

15. An assembly as claimed in any one of the preceding claims, wherein a head tracking means that guides the door panels is a finger connected to and extending in a direction upwardly from the top of at least one of the 5 door panels and wherein said finger locates in an elongate head cavity in said head and wherein said head cavity defines a head track in which said finger can traverse in a direction that extends along a longitudinal extent of the head. 10

16. An assembly as claimed in claim 15, wherein said finger carries a wheel that can rotate about an upright axis and wherein the wheel locates in said cavity and acts to guide the top of at least one of door panels as the 15 door panels are opened and closed.

17. An assembly as claimed in any one of the preceding claims, wherein the sill is a two part sill with a first part defining a part of the outside side of said cavity, 20 the second part defining a part of the inside side of said cavity, and wherein the first part and the second part are connectable and collectively define the sill and the cavity, and wherein the weight bearing surface can be inserted or removed from the cavity by disconnecting or 25 reconnecting the first part and the second part.

18. An assembly as claimed in claim 17, wherein the first part and the second part are provided with co-operating snap lock fitting surfaces that permit snap lock engagement or disengagement of the first part and the 30 second part for the connection and disconnection of the first part and the second part.

19. An assembly substantially as herein described with reference to the accompanying drawings. 35 2609752_1 (GHMatters) P50283.AU.I 21/03/11