Abstract:
A folding closure ( 20 ), such as a bifold door or window, comprises at least three hinged panels ( 21, 21, 23, 24 ) suspended from the track. The panels can be folded about their hinged connections, from a closed configuration whereat they are aligned substantially in a plane, to an open configuration whereat they are juxtaposed in substantially parallel planes orthogonal to the plane. An end panel ( 21 ) is hinged to a jamb by an offset hinge ( 25 ). At least one pair of adjacent panels ( 21, 23  and/or  22, 24 ) are hinged together by at least one offset hinge ( 30, 31 ), to compensate for the offset of the end panel ( 21 ), and thereby permit all the panels to be of substantially equal width.

Description:
TECHNICAL FIELD  
       [0001]     This invention relates to a folding closure, such as a folding door or window, having a plurality of hinged panels, all of which are of substantially the same width. In particular, the invention is directed to a folding door or window comprising at least three hinged panels of equal width, of which at least two panels are joined by offset hinges.  
       BACKGROUND OF THE INVENTION  
       [0002]     Folding doors and windows are a popular building choice, due to their ability to provide clear unimpeded openings in a wall. A typical folding door or window comprises a plurality of hinged panels suspended from one or more carriages which travel along an overhead track. A carriage and a hinge may be combined to form a carrier hinge in which the hinge pin serves to suspend the hinge (and affixed panels) from the carriage, as shown in U.S. Pat. No. 6,618,900.  
         [0003]     The panels may open by folding, in concertina fashion, to one side of the opening. Alternatively, particularly for wide openings, the panels may be formed as two hinged sets which fold to opposite sides of the opening. In both cases, the panels fold open to an orientation in which they are juxtaposed parallel to each other, 90° to the plane of the opening, to minimise the width of the opening they occupy.  
         [0004]     A plan view of a conventional folding door or window  10  is shown schematically in  FIG. 1 . The illustrated closure comprises an end or jamb panel “A” which is adjacent the jamb  15  and hinged thereto by a single-leaf hinge  11 , a leading panel “B” which is furthest from the jamb, and a pair of intermediate panels “C”, “D” which are hinged to the jamb and leading panels, respectively, typically by upper and lower butt hinges  12  edge-fixed to those panels. The two intermediate panels C, D are also hinged together by upper and lower edge-fixed butt hinges (not shown), the upper hinge being suspended from a carriage  13 . The distal end of the leading panel B is suspended from the track by a single-leaf carrier hinge  14 .  
         [0005]     To ensure that the proximal end face of the jamb panel A closes sufficiently close to the jamb face  15  to provide adequate weatherproofing, the jamb panel A is hinged to the jamb  15  by upper and lower offset hinges  11  each having a single angled leaf, i.e. the mounting face of each hinge leaf is offset from its hinge axis. Similarly, to ensure that the distal end face of the leading panel B closes sufficiently close to the opposite jamb, or an opposing leading panel, to provide adequate weatherproofing, the leading panel B is hinged to the carriage  14  by at least an upper offset hinge having a single angled leaf.  
         [0006]     Consequently, as can be seen in  FIG. 1 , the jamb and leading panels A, B have a width “W” which is greater than the width of the intermediate panels C, D by an amount “w”, being the hinge offset. An inherent disadvantage of such folding doors and windows is that the panels must be manufactured in two different sizes. This adds significantly to manufacturing and inventory costs. Furthermore, errors may occur in installation due to the wrong sized panel being mounted in the wrong position.  
         [0007]     U.S. Pat. No. 4,295,514 discloses a bifold door assembly comprising two door panels of equal width. The panels are joined by hinges having knuckles offset from the panel edges, to permit the door panels to be opened to an obtuse position, i.e. greater than 90°. However, while this may be an advantage for a small two panel bifold cupboard door, it is not applicable to most large doors and windows having three or more panels as the jambs of such doors and windows do not normally permit the panels to open to an obtuse orientation, nor is it usually desired to fold the panels open to an obtuse orientation.  
         [0008]     Moreover, the hinge arrangement of the &#39;514 patent is unsuitable for conventional folding closures of three or more hinged panels for several reasons. First, as can be seen from  FIG. 5  of the &#39;514 patent, the panels cannot be arranged parallel to each other and at 90° to the plane of the opening. If the end panel is folded against a jamb at 90° to the plane of the opening, the adjacent panel will be angled obliquely, which not only occupies more of the opening space, but also detracts from the aesthetic appearance of the folded panels.  
         [0009]     Secondly, if a third panel were to be added to the embodiment shown in  FIG. 5  of the &#39;514, say for a wider opening, the axis of the hinge connection of that third panel to its adjacent panel would not follow the guide track, and hence a carrier hinge could not be used.  
         [0010]     Thirdly, the hinge arrangement of the &#39;514 patent is designed for bifold doors having pivots and guides within the perimeter or plan section of the door, unlike many suspended folding doors in which the hinge axis (or axes) of each panel is (or are) located outside the plan section of the panel.  
         [0011]     It is an aim of this invention to provide an improved folding closure with panels of equal width, which overcomes or ameliorates one or more of the disadvantages or problems described above.  
       SUMMARY OF THE INVENTION  
       [0012]     In one broad form, this invention provides a folding closure comprising an overhead track, and at least three hinged upright panels of substantially equal width suspended from the track. The panels are adapted to be folded about their hinged connections from (a) a closed configuration whereat they are aligned substantially in a plane to (b) an open configuration whereat they are juxtaposed in substantially parallel planes orthogonal to the plane. At least one pair of adjacent panels of the closure are hinged together by at least one offset hinge.  
         [0013]     Where the context permits, the term “offset hinge” as used herein is intended to mean a hinge having one or more leaves each adapted to be fixed to a respective panel, the plane of the fixing face of each leaf being offset from the hinge axis.  
         [0014]     The closure is typically a door or window, but could be a screen, shutter, partition or the like. The term “panel” as used herein is intended to include any generally planar component of a folding door, window, screen, partition or the like, whether glazed or unglazed. The invention has particular application to an external folding door or window of a building, but is not limited thereto, as it can also be applied to internal partitions.  
         [0015]     Normally, a first or end panel of the closure is hinged to a jamb member by at least another (single leaf) offset hinge. The use of the offset hinge between at least a pair of adjacent panels compensates for the offset introduced by the end panel, and enables panels of equal width to be used in the folding closure.  
         [0016]     Preferably, each offset hinge which is connected between a pair of adjacent panels is a double-leaf non-mortise offset hinge in which one leaf fits within the other. Each such offset hinge is suitably edge-fixed to the pair of adjacent panels, i.e. fixed to opposed end faces of the panels by screws or other fasteners. However, the offset hinge may alternatively be face-fixed to the pair of adjacent panels, i.e. fixed to a side of each panel.  
         [0017]     Typically, the pair of adjacent panels are hinged together by two offset hinges located respectively near the top and bottom of the panels. A third offset hinge may be connected to the pair of adjacent panels between the two offset hinges. The third offset hinge may be provided with a handle.  
         [0018]     Normally, each of the panels is mounted for pivoting about an axis or axes outside the respective panel.  
         [0019]     Preferably, the folding closure includes at least one carriage adapted to travel along the track. A pair of adjacent panels of the folding closure can be joined by a hinge which is connected to the carriage and suspended therefrom. (This may be the pair of adjacent panels connected by the offset hinge(s), or another pair).  
         [0020]     In another form, the invention provides a method of forming a folding closure, comprising the steps of: suspending at least three hinged panels of substantially equal width from a track, such that the hinged panels can be folded from (a) a closed configuration whereat they are aligned substantially in a plane to (b) an open configuration whereat they are juxtaposed in substantially parallel planes orthogonal to the plane; and joining at least one pair of adjacent panels of the closure by at least one offset hinge.  
         [0021]     In yet another form, the invention provides a folding closure for an opening in a building, comprising at least three hinged panels of equal width, the panels being adapted to be folded about their hinged connections from (a) a closed configuration whereat they are aligned substantially in a plane to (b) an open configuration whereat they are juxtaposed in substantially parallel planes orthogonal to the plane, and wherein at least one pair of adjacent panels are hinged together by at least one offset hinge.  
         [0022]     In order that the invention may be more readily understood and put into practice, preferred embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]     Preferred embodiments of the invention are described below with reference to the following accompanying drawings.  
         [0024]      FIG. 1  is a plan view of a prior art folding closure.  
         [0025]      FIG. 2  is a plan view of a folding closure according to one embodiment of the invention.  
         [0026]      FIG. 3  is a plan view of the folding closure of  FIG. 2  with top mount and carriages removed to show the hinges.  
         [0027]      FIG. 4  is a perspective view of the folding closure of  FIG. 2  (when open).  
         [0028]      FIG. 5  is a perspective view of an offset hinge in one configuration.  
         [0029]      FIG. 6  is a perspective view of the offset hinge of  FIG. 5  in another configuration.  
         [0030]      FIG. 7  is a perspective view of an offset hinge with handle attached.  
         [0031]      FIG. 8  is a plan view of a folding closure (when open) according to a second embodiment of the invention.  
         [0032]      FIG. 9  is a plan view of the folding closure  FIG. 8 , with carriage omitted.  
         [0033]      FIG. 10  is a plan view of the folding closure of  FIG. 8 , when closed.  
         [0034]      FIG. 11  is a plan view of the folding closure of  FIG. 10  with carriage omitted.  
         [0035]      FIG. 12  is a plan view of a folding closure according to a third embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0036]     This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8).  
         [0037]     As shown in FIGS.  2  to  4 , a folding closure  20 , which may be a folding door or window, comprises four hinged panels  21 - 24 . A jamb panel  21  is hinged to a jamb (not shown) by top and bottom single-leaf offset hinges  25 , as is known in the art. A leading panel  22  is suspended from a carriage  27  by a single-leaf offset hinge  26 , again as is known in the art. Two intermediate panels  23 ,  24  are hinged together at one end thereof by top and bottom edge-fixed butt hinges  28 , the upper hinge being suspended from a carriage  29 , as is known in the art. It is to be noted that the hinge axes of hinges  25 ,  26 ,  28  are aligned with the centreline  19  of the track (not shown) on which the carriages  26 ,  29  travel. Thus the carriages  26 ,  29  can form part of respective carrier hinges.  
         [0038]     At its other end, intermediate panel  23  is hinged to the jamb panel  21  by top and bottom double-leaf offset hinges  30 . Similarly, at its other end, intermediate panel  24  is hinged to the leading panel  22  by top and bottom double-leaf offset hinges  31 .  
         [0039]     The construction of the offset hinges  30 ,  31  is shown in more detail in  FIGS. 5 and 6 .  FIG. 5  shows the hinge with its hinge leaves at 180° (which is the configuration of the hinge when the panels are folded to an open position as shown in  FIGS. 2-4 ).  FIG. 6  illustrates the hinge with its hinge leaves at 0° (which is the configuration of the hinge when the panels have been extended to a closed position). At this configuration, the leaves interfold into the thickness of a single leaf, i.e. the hinge is a non-mortise hinge.  
         [0040]     As shown in  FIGS. 5 and 6 , each hinge  30 ,  31  has a pair of interfolding or interfitting leaves  32 ,  33  adapted to be screwed to an edge face of a respective one of a pair of adjacent panels. Each leaf  32 ,  33  has a knuckle portion  32 A,  33 A, respectively with a bore through it. A hinge pin (not shown) is located within the aligned bores, and defines a hinge axis A about which the hinge leaves  32 ,  33  can pivot.  
         [0041]     However, unlike the known regular butt hinges  12  used between adjacent panels on conventional folding closures as shown in  FIG. 1 , the hinge leaves  32 ,  33  are substantially offset from the hinge axis A. That is, the hinge axis A is offset or spaced from the plane defined by the face of each hinge leaf  32 ,  33  which is fixed to the panel.  
         [0042]     The total offset distance, i.e. the transverse spacing between the fixing faces of the hinge leaves when they are at 180°, is selected to counter the offset of the single-leaf offset hinges used on the jamb and leading panels. In this manner, all panels  21 - 24  can be made of the same width and still have their carriages aligned on the track, as can be seen clearly in  FIG. 3 . Consequently, manufacturing can be standardised and inventory can be reduced, thereby reducing overall costs of manufacture.  
         [0043]     For tall panels, such as door panels, intermediate offset dual-leaf hinges  34  may be fixed to adjacent panels between the top and bottom hinges, as shown in  FIG. 4 . The construction of each intermediate offset hinge  34  is shown in more detail in  FIG. 7 . The intermediate hinge  34  is of similar construction to the top and bottom offset hinges  30 ,  31 , but is provided with a handle  35  to facilitate folding of the panels from their flat (closed) configuration.  
         [0044]     The advantages of the invention can also be obtained by using different positioning of the offset hinges.  FIGS. 8-11  illustrate another embodiment of the invention. In this three-panel embodiment, a folding closure  40  comprises a jamb panel  41 , a leading panel  42  and an intermediate panel  43 . The jamb panel  41  is connected to the jamb  44  by a single leaf offset hinge  45 . The jamb panel  41  is also hinged to the intermediate panel  43  by top and bottom regular (flat leaf) butt hinges  46 , each having a leaf edge-mounted to the respective panel. For tall panels, such as in a folding door, an intermediate hinge with a handle  47  may also be provided.  
         [0045]     The intermediate panel  43  is also hinged to the leading panel  42 , but by top and bottom dual-leaf offset hinges  48 , the top hinge  48  being suspended from a carriage  49 . In this embodiment, the leaf of hinge  48  which is fixed to the intermediate panel  43  should have the same amount of offset as that of hinge  45 . This enables all of the panels  41 - 43  of the embodiment of  FIGS. 8-11  to be of the same width, yet the axis of hinge  48  still aligns with the track line  50 , enabling the hinge  48 , and carriage  49  to be combined as a carrier hinge.  
         [0046]     The principal advantage of the invention, i.e. a folding closure with panels of equal width, can also be achieved by replacing each hinge  48  with a regular butt hinge, and each hinge  46  with an offset hinge having the appropriate amount of offset. That is, the jamb panel  41  and the intermediate panel  43  can be hinged together using top and bottom offset hinges, while the intermediate panel  43  and the leading panel  42  can be hinged together using top and bottom flat leaf butt hinges.  
         [0047]     In another variation, hinges  46  and  48  of the embodiment of  FIGS. 8-11  can be replaced by two offset hinges, each of appropriate offset, so that the axis of hinge  48  remains aligned with track line  50 .  
         [0048]     In yet another embodiment, a folding closure with panels of equal width can be obtained by replacing each hinge  30  of the embodiment of  FIGS. 2-4  with a regular butt hinge, and fixing offset hinges between panels  23  and  24 , and between  24  and  22 , as shown applied to a five panel closure in  FIG. 12 . In this case however, the offset hinges will have twice the amount of offset of the offset hinges of  FIGS. 2-4 .  
         [0049]     The foregoing embodiments are illustrative only of the principles of the invention, and various modifications and changes will readily occur to those skilled in the art. For example, although the illustrated embodiments use edge-fixed hinges, the invention can also utilise face-fixed offset hinges.  
         [0050]     In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.