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FIELD OF THE INVENTION 
       [0001]    The present invention relates to modular housing and in particular, to housing formed from modules which can be repeatedly transported to a location, erected (or raised) at that location, lowered, and then transported to another location. 
       BACKGROUND ART 
       [0002]    Two published international patent applications namely WO2011/120057 and WO2013/044301 disclose such modules but have not, as of the priority date of the present application, been erected or constructed. The contents of both international applications are hereby incorporated into the present specification for all purposes. 
         [0003]    A repeatedly erectable module which has four columns is disclosed in the abovementioned patent specifications. Each column is located at a corresponding corner of the module. Each column is provided with a roof hinge, a central hinge, and a floor hinge. Thus each column has three hinges. The columns fold between an initial transport configuration and an erected configuration. In the transport configuration the two main portions of the column lie alongside each other. In the erected configuration all the portions of the column are substantially aligned. Each of the hinges preferably includes two parts which overlap when the portions of the column are aligned. 
         [0004]    In order to maintain the column portions in an aligned condition, a fastener has been intended to pass through the overlapping portions of the hinge. In a typical proposed arrangement the fastener would have a threaded shank which mates with a threaded orifice in one of the overlapping portions. 
         [0005]    Various disadvantages are associated with, this proposed method of maintaining the column portions aligned. Firstly, it takes some time to screw in each of the fasteners during the erection phase, and subsequently unscrew the fasteners if the module is to be moved. In addition, during the move the fasteners may well be lost. Thirdly, where the fasteners are provided with a conventional head such as a Phillips screw head or a slotted head, pranksters or malicious malcontents may undo the fasteners. 
         [0006]    Furthermore, during the erection procedure it is desirable that personnel not enter the structure until the columns have been reliably placed in their erected condition and the hinges prevented from bending or otherwise giving way. Still further, during the lowering procedure, the weight carried by the columns, corrosion, and various other factors may prevent the threaded fastener being undone. Finally, it is desirable that the hinges be latched or locked into their erected position without any give since a fraction of a millimetre movement at the hinge translates into many millimetres of movement or slack at the end of the column portions. 
       GENESIS OF THE INVENTION 
       [0007]    The genesis of the present invention is a desire to provide an improved releasable lock and thereby improve the arrangements for fastening such hinge columns. 
       SUMMARY OF THE INVENTION 
       [0008]    In accordance with a first aspect of the present invention there is disclosed an interior locking mechanism for a hollow column having at least two portions which are hinged together, said mechanism comprising:
       an interior lip on one of two hinge members able to be mounted on one of said column portions,   a latch member pivoted to the other of said hinge members, said other hinge member being able to be mounted on the other of said column portions,   a hinge means interconnecting said two hinge members,   said latch, member having a rounded head able to be displaced in a first direction from a rest position to permit said lip to move past said head,   biasing means to urge said latch member in a second direction opposite to said first direction, and   a positive drive means interconnecting said latch member and said other hinge member and operable to drive said latch in said second direction to force said latch member into abutting engagement with said lip to lock said hinge members together, and operable to drive said latch in said first direction to release said lock.       
 
         [0015]    In accordance with a second aspect of the present invention there is disclosed a method of ensuring re-opening of a hinge latch mechanism, said method comprising the steps of:
       providing a locking lip on a first hinge member.   pivoting a latch member on a second hinge member to be pivotable between two positions, a first position free of said locking lip and a second position engaged with said locking lip, and   interconnecting said first hinge member and said latch member with a positive drive means operable to drive said latch member in a first direction to release said latch member from said locking lip, and in a second direction to force said latch member into abutting engagement with said locking lip.       
 
         [0019]    Preferably the method includes the further steps of:
       providing a threaded shaft which passes freely through, and is rotatably mounted in, an aperture in said second hinge member,   providing a threaded orifice in said latch member,   threadably engaging said threaded shaft with said threaded orifice, and   rotating said threaded shaft in either one of two opposite directions to respectably urge said latch member into, or out of, engagement with said locking lip.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    Three embodiments of the present invention will now be described with reference to the accompanying drawings in which: 
           [0025]      FIG. 1  is a perspective view of a column provided with a hinge movable through 90° and illustrated in an aligned condition, the view being from the rear of the hinge; 
           [0026]      FIG. 2  is a perspective view of the column of  FIG. 1  but viewed from the front of the hinge; 
           [0027]      FIG. 3  is a perspective view of the column of  FIG. 2  showing the hinge fully open; 
           [0028]      FIG. 4  is a perspective view of the hinge prior to its insertion into the tubular members which form the column: 
           [0029]      FIG. 5  is a perspective view from below the of the rear of the upper portion of the hinge of  FIG. 4 ; 
           [0030]      FIG. 6  is a perspective view of the front of the upper portion of the hinge of  FIG. 4 ; 
           [0031]      FIG. 7  is a perspective view of the front of the lower portion of the hinge of  FIG. 4 ; 
           [0032]      FIG. 8  is a cross-sectional view taken vertically through the hinge of  FIG. 3  and showing the hinge open; 
           [0033]      FIG. 9  is a view similar to  FIG. 8  but showing an intermediate stage in the locking of the hinge; 
           [0034]      FIG. 10  is a view similar to  FIG. 9  but showing a further intermediate stage in the locking of the hinge, and with the latch member being illustrated in cross-section; 
           [0035]      FIG. 11  is a view similar to  FIGS. 8-9  but showing the hinge in its locked condition; 
           [0036]      FIG. 12  a front perspective view of the locking mechanism of the hinge; 
           [0037]      FIG. 13  is a rear perspective view of the locking mechanism of  FIG. 11 ; 
           [0038]      FIG. 14  is a front perspective view of the latch member of the locking mechanism: 
           [0039]      FIG. 15  is a perspective view of an actuator which actuates the locking mechanism; 
           [0040]      FIG. 16  is an exploded perspective view of the actuator of  FIG. 14  with the central body of the actuator shown in cross-section; 
           [0041]      FIG. 17  is a perspective view of two threaded fasteners included within the locking mechanism of  FIGS. 12 and 13 ; 
           [0042]      FIG. 18  is a cutaway perspective view showing the interior of the hinge; 
           [0043]      FIG. 19  is a perspective view of a hinge of a second embodiment which is capable of movement through 180°, the column within which the hinge is installed being only partially opened, being fitted with an electrical cable, and being provided with the same locking mechanism as the hinge of the first embodiment; 
           [0044]      FIG. 20  is a view of the hinge and column of  FIG. 19  with the hinge being fully opened to 180°; 
           [0045]      FIG. 21  is a cutaway perspective view showing the interior of the hinge of  FIGS. 19 and 20 ; 
           [0046]      FIG. 22  is a cutaway perspective view showing the hinge in its partially closed position; 
           [0047]      FIG. 23  is a cutaway perspective view showing the hinge in the fully closed position, 
           [0048]      FIG. 24  is a perspective view of the hinge of the third embodiment with the locking mechanism set in the start position, 
           [0049]      FIG. 25  is a perspective view of the hinge of  FIG. 24  with the locking mechanism said in the unlatched position, 
           [0050]      FIG. 26  is a perspective view of the hinge of  FIGS. 24 and 25  in the closed but unlatched position, 
           [0051]      FIG. 27  is a perspective view of the hinge of  FIGS. 24-26  in the latched and locked position, 
           [0052]      FIG. 28  is a perspective view similar to  FIG. 12  but illustrating, the locking mechanism of the third embodiment, 
           [0053]      FIG. 29  is a perspective view of the reverse side of the locking mechanism of  FIG. 28 , and 
           [0054]      FIG. 30  is an exploded perspective view of the hinge of the third embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0055]    As seen in  FIGS. 1 and 2  a column  1  has an upper portion  2  and a lower portion  3  which are interconnected by means of a hinge  4 , as illustrated in isolation in  FIG. 4 . The hinge  4  has an upper housing  6  and a lower housing  7  which are interconnected by means of a pin  8 . A locking mechanism  10  including an L-shaped latch member  11  is mounted within the upper housing  6  as illustrated in  FIG. 3 . As best seen in  FIG. 8 , the lower housing  7  has an interior locking lip  12  with which the latch member  11  can engage as seen in  FIGS. 10 and 11 . 
         [0056]    Turning to  FIGS. 12 and 13 , the locking mechanism  10  has a central axle  14  on which a pair of shoulders  15  are pivoted. The shoulders  15  have a centrally located cylindrical yoke  16  which has two protruding pins  17  which function as pivot points. In addition, the shoulders  15  include two arms  18 ,  19  each of which carries a corresponding stub axle  28 ,  29 . The stub axles  28 ,  29  are retained in apertures  30  in the upper housing  6  as best seen in  FIG. 4  in relation to stub axle  28 . 
         [0057]    As best seen in  FIG. 13 , the central axle  14  has a spring  21  located thereon which is wound, tensioned and arranged to urge both the arms  18 , 19  anticlockwise as seen in  FIG. 8  and to also urge the free end of the latch member  11  towards the locking lip  12 . A fastener  20  passes through the yoke  16  and also through a frusto-conical opening  26  ( FIG. 6 ) in the upper housing  6  of the hinge  4 . 
         [0058]    In addition, the latch member  11  is provided with two fasteners  23 ,  24  each of which has a threaded shank which is engaged with a corresponding nut  33 ,  34  having a curved proximal surface  35  (as best seen in  FIGS. 13 and 17 ). In addition each nut  33 ,  34  is provided with an arcuate ridge  37 ,  38  ( FIG. 17 ) which mates with a corresponding one of a pair of arcuate grooves  39 ,  40  ( FIG. 13 ) on the latch member  11 . The shanks of the fasteners  23 ,  24  pass through corresponding openings  43 ,  44  in the latch member  11  (as best seen in  FIG. 14 ) and through frusto-conical openings  53 ,  54  in the upper housing  6  (as best seen in  FIG. 6 ). In addition, the latch member  11  is provided with a central opening  31  ( FIG. 14 ) in which is received an actuator  41  as illustrated in  FIGS. 15 and 16 . The distal end of the actuator  41  has a through hole  42  through which a cotter pin  46  passes, as seen in  FIG. 13 , in order to retain the actuator  41  in the central opening  31 . 
         [0059]    As best seen in  FIG. 14 , the central opening  31  is provided with two curved partially spiral surfaces  61 ,  62  and two corners  63 ,  64  as well as a circular opening  65 . The circular opening  65  forms a bearing for the distal end of the actuator  41  which includes the through hole  42  for the cotter pin  46 . Furthermore, as best seen In  FIGS. 5 and 6 , the central opening  31  is provided with a part circular rim  67  having two gaps  68  and  69 . In addition, opposite the central opening  31  on the lower housing  7  is a shaped bite  71  which has a trip lip  72  ( FIG. 7 ). 
         [0060]    As seen in  FIGS. 15 and 16 , the actuator  41  has a body  50  which is provided with two ramped spiral surfaces  48 ,  49 . These mate with the curved spiral surfaces  61 ,  62  of the central opening  31 . In addition, the actuator  41  is provided with two flat ends  55 ,  56 . Furthermore, the actuator body  50  includes a lug  51  and is press fitted into a cylindrical boss  52  having an O-ring  57 . 
         [0061]    The distal end of the actuator  41  takes the form of an actuator pin  45  reciprocally mounted within the actuator body  50 . The distal end of the actuator pin  45  is provided with the through hole  42 . An internal spring  58  urges the actuator pin  45  to the left as seen in  FIGS. 15 and 16 . In  FIG. 15  the actuator pin  45  is illustrated extended from the actuator body  50  which corresponds with the position of the actuator  41  illustrated in  FIG. 12 . In  FIG. 16  the actuator pin  45  is illustrated in its rest position which corresponds to the position of the actuator  41  illustrated in  FIG. 11 . As best seen in  FIG. 12 , the boss  52  of the actuator  41  is provided with a hexagonal drive recess  47  and a marker groove  151  which is aligned with the lug  51 . 
         [0062]    During the erection procedure, the hinge  4  is initially in the position illustrated in  FIG. 8  where the fastener  20  has been rotated so as to move the shoulders  15  into the position illustrated in  FIG. 8 . Furthermore, the fasteners  23 ,  24  have been rotated relative to the nuts  33 ,  34  so that the free end of the latch member  11  is moved towards the interior of the column  1 . In addition, the actuator  41  is turned so that the marker groove  151  is approximately in a “9 o&#39;clock” position as seen, for example, in  FIG. 3 . These actions, in effect, prime the hinge for its initial operation. 
         [0063]    As the two portions of the column  1  are moved together as the hinge closes, the locking mechanism  10  is initially moved into the position illustrated in  FIG. 9 , and if necessary, the rounded head of the latch member  11  passes over the interior rim of the lower housing  7 . The trip lip  72  pushes the lug  51  in a clockwise direction as seen in  FIG. 12 , for example, so that the lug  51  is moved into approximately the “10 o&#39;clock” position. In this position the lug  51  becomes aligned with the gap  68  which enables the actuator  41  to be driven forwardly by the spring  21  as the latch member  11  moves to engage the locking lip  12 . This places the latch member  11  into the position illustrated in  FIG. 10  in which it will be seen that the boss  52  of the actuator  41  protrudes outwardly. 
         [0064]    Thereafter, the fasteners  20 ,  23  and  24  are all screwed inwardly. This draws the shoulders  15  and latch member  11  into the locked position illustrated in  FIG. 11 , if they have not already been driven there by the spring  21 . In either event, the latch member  11  is locked into the latched position. In particular, this positive locking eliminates any play between the two housings  6 ,  7  of the hinge and therefore eliminates any play between the two portions  2 ,  3  of the column  1 . 
         [0065]    It will be apparent from  FIGS. 5 and 6 , and  FIGS. 12-18  that the actuator  41  interacts with the L-shaped latch member  11  as follows. The internal spring  58  urges the actuator  41  to the left as seen in  FIG. 15 . As a consequence, if the lug  51  is aligned with gaps  68  in the rim  67 , then the boss  52  of the actuator  41  will protrude from the upper housing  6  if the latch member  11  is engaged with the locking lip  12 . The cotter pin  46  prevents the actuator  41  from coming out of the hinge  4  altogether. 
         [0066]    In this position, the boss  52  provides a visible indication that the latch member  11  is engaged with the locking lip  12  which is important because neither the latch member  11  nor the locking lip  12  are visible to persons erecting the structure since they are hidden within the interior of the column  1 . As a consequence, during the erection of the structure, as the roof is raised, the hinges  4  snap shut and each boss  52  can be seen protruding from the corresponding hinge  4  which thereby provides a visual (and to some extent aural) indication to personnel erecting the structure that it is safe to enter and that the erected columns have been latched as desired. Thereafter the fasteners  20 ,  23 ,  24  can be manipulated as described above to positively lock the latch member  11  against the locking lip  12  and eliminate any play between the two portions  2 ,  3  of the column  1 . Next, the actuator  21  can be turned slightly clockwise so as to align the marker groove  151  with the gap  69 . The lug  51  can then pass through the gap  69  so as to return the boss  52  to position substantially flush with the upper housing  6 . This is the situation illustrated in  FIG. 11 . 
         [0067]    In the event that it is necessary to lower the structure of which the column  1  is a part, the fasteners  20 ,  23  and  24  are turned so as to drive the free end of the latch member  11  in a clockwise direction as seen in  FIG. 11  with the intention of placing the latch member  11  into the position illustrated in  FIG. 9 . However, because of the mechanical load on the column  11  this intended rotation of the latch member  11  may not take place. Thus, instead of the heads of the fasteners  23 ,  24  remaining flush with the housing  6 ,  7 , and the latch member  11  being pushed out of engagement with the locking lip  12 , these fastener heads may protrude from the hinge  4 , in which case the latch member  11  remains in its fully latched position. In this connection, it should be noted that the head of the fastener  20  is captive between the upper housing  6  and the upper portion to the column  1 . This is simply arranged by ensuring that the opening in the upper portion  2  which allows access to the head of the fastener  20 , is slightly smaller in diameter than the outer diameter of the head of the fastener  20 . 
         [0068]    In order to counteract this “sticking” situation, the actuator  41  is rotated so that the ramp spiral surfaces  48 ,  49  on the actuator  41  ride over the curved spiral surfaces  61 ,  62  on the latch member  11 . As a consequence, the flat ends  55 ,  56  move out of the central opening  31  and bear on the front surface  70  (as illustrated in  FIG. 14 ) of the latch member  11 . In this position of the actuator  41 , the lug  51  moves to the inside of the rim  67 . Continued rotation of the actuator  41  means that the engaged spiral surfaces  48 ,  49 ,  61  and  62  moves the actuator  41  towards the latch member  11 . This urges the latch member  11  out of engagement with the locking lip  12  and into the position illustrated in  FIG. 9 . In this position the heads of the fasteners  23 ,  24  are flush with the outer surface of the hinge. 
         [0069]    In the unlikely event that the latch member  11  is stuck against the locking lip because of corrosion, the presence of nests of insects, and other such unlikely occurrences, then the rotation of the fastest  23 ,  24  will drive the heads of the fasteners  23 ,  24  out of the flush position illustrated in  FIG. 11  the proud heads of the fastest  23 ,  24  can then be struck with a hammer so as to forcibly drive the latch member  11  out of engagement with the locking lip  12  and into the unlatched position illustrated in  FIG. 9 . 
         [0070]    Once the latch member  11  is so positioned, the hinge  4  can then be rotated through 90° so as to place it in the condition illustrated in  FIG. 8 . After the hinge has been opened, the actuator  41  is preferably turned by the operator so as to place the marker groove  151  in the “4 o&#39;clock” position illustrated in  FIG. 12 . This ensures that the latch mechanism always stays open even during transport. Before the next roof erection or raising, the actuator  41  is turned so that the marker groove  151  is in the “9 o&#39;clock” marker groove position. This action primes the latch and places it in its initial condition prior to operation. 
         [0071]    Turning now to  FIGS. 19-23 , a hinge  104  of the second embodiment is illustrated for a column  101  having two portions  102  and  103 . The hinge  104  is capable of being bent through 180°, not merely 90° as in the case of the hinge  4  of the first embodiment. In order to provide for the extra opening range, the pin  8  of the first embodiment is replaced by two pairs of U-shaped arms  108  which have five pins  111 - 115 . The asymmetrical nature of the U-shaped arms  108  provides a convenient opening through which an electric cable  120  can be passed. The hinge  104  is also provided with the locking mechanism  10  as described in detail in relation to the first embodiment. 
         [0072]    In addition, the hinges  4 ,  104  can be used in either orientation, up or down, since the locking action is not dependent upon gravity. Which orientation is used will often be dependent upon which orientation results in the fastener  20  being either accessible, or more accessible. 
         [0073]    A third embodiment of the hinge of the present invention is illustrated in  FIGS. 24-30 . A particular advantage of the hinge of the third embodiment is that it enables the hinge mechanism to be easily removed from the columns. The hinge of the third embodiment differs from that of the previous embodiments in that a cover plate  220  and cylindrical spacing, bush  221  are provided to ensure that the head of the fastener  20  cannot extend beyond the outer surface of the hinge. In addition, as best seen in  FIG. 30 , each of the fasteners  20 ,  23 , and  24  is provided with a small hole adjacent the free end of the shank of the fastener. A roll pin  222  is inserted into each free end in order to retain the fastener within the locking mechanism. The roll pins  222  are preferably inserted (and if necessary removed) using the roll pin manipulator described in Australian Patent Application No 2014 901 521. The fasteners  20 ,  23  and  24  may need to be replaced in the event that their thread becomes worn. 
         [0074]    As best seen in  FIGS. 28-30 , the latch is retained within the column by two pins  225 ,  226  each of which has a corresponding push on cap  227  which is essentially cosmetic and is intended merely to hide the head of the pins  225 ,  226  in the finished assembly. The pins  225 ,  226  are retained in the arms  18  and  19  by means of a friction fit. The pins  225 ,  226  are each provided with an internally threaded blind aperture which permits an extraction tool to be screwed into the pins and the pins pulled from the latch, thereby freeing the latch mechanism and allowing it to be removed 
         [0075]    In addition, as best seen in  FIG. 27  the outer surface of the hinge is provided with  4  symbols at the 4 o&#39;clock, 9 o&#39;clock, 10 o&#39;clock and 12 o&#39;clock positions into which the marker groove  151  of the actuator  41  can be moved. These positions respectively correspond to the transport position, the latch open position, the latch closed but unlocked position, and the latch locked position. 
         [0076]    Once the structure has been erected, in order to lower the structure, the following sequence is followed. Firstly, the fastener  20  and the fasteners  23 ,  24  are backed off as far as possible and the actuator  41  is turned so that the marker groove  151  is in the 4 o&#39;clock position. This guarantees that the latch is both open and cannot be moved. Once all the hinges are in this position, the crane can take the weight of the roof, which then enables the hinges to pivot and the columns to be moved out of the vertical condition. With the marker groove  151  in the 4 o&#39;clock position, the structure can be transported from place to place and the latch is left in the open position until the structure is re-erected. 
         [0077]    Prior to that re-erection taking place, the actuator  41  is rotated so that the marker groove  151  is in the 9 o&#39;clock position meaning that the, latch is open and is able to be tripped by the raising of the columns into the vertical position. Once the roof is raised and the columns become vertical, the hinges latch with an audible click and the latch mechanism moves the actuator  41  so that the marker groove  151  is in the 10 o&#39;clock position. In this position the cylindrical boss  52  protrudes from the hinge as shown in  FIG. 26 . Thereafter the fasteners  20 ,  23  and  24  are driven home and the actuator  41  rotated so that the marker groove  51  is then in the 12 o&#39;clock position indicating that the hinges are both latched and locked. 
         [0078]    The foregoing describes three embodiments of the present invention and modifications, obvious to those skilled in the building arts, can be made thereto without departing from the scope of the present invention. 
         [0079]    The term “comprising” (and its grammatical variations) as used herein is used in the inclusive sense of “including” air “having” and not in the exclusive sense of “consisting only of”.

Summary:
A locking mechanism ( 10 ) for a hinge ( 4 ) is disclosed. A latch member ( 11 ) engages with a lip ( 12 ). A positive drive means ( 20, 23, 24, 41 ) enables the latch member to be driven into and out of engagement with the lip. The driven engagement when the hinge is used in relation to columns ( 1, 101 ) prevents small movements at the hinge being magnified into large movements at the end of the column members. The driven dis-engagement enables the hinge to be opened notwithstanding mechanical loads, corrosion, insect nests and similar obstacles. The drive means preferably takes two forms, namely threaded fasteners ( 20, 23, 24 ) and a spring loaded rotatable actuator ( 41 ) with ramped surfaces ( 48, 49 ) which male with ramped surfaces ( 61, 62 ) on the latch member ( 11 ).