Abstract:
A joint arrangement joining adjacent edges of two structural elements ( 10, 11 ). The joint arrangement includes a joiner element ( 12 ) which has projections ( 17, 18 ), each of which is slidingly engageable in a groove ( 19, 20 ) of the respective structural elements ( 10, 11 ). The joiner element ( 12 ) has a spine means ( 22 ) which in the assembled joint engages between profiled edge portions of the structural elements ( 10, 11 ). The distal end ( 24 ) of the spine ( 22 ) has two oppositely disposed lateral projections ( 25, 26 ) each of which engage in a groove ( 27, 28 ) formed in the profile edge of the adjacent structural element ( 10, 11 ).

Description:
BACKGROUND TO THE INVENTION  
         [0001]    This invention relates to improvements in demountable structures such as cabinets which can be used for display purposes and to a joint arrangement for use in demountable structures.  
           [0002]    In our international patent specification WO 99/08575 there is disclosed a cabinet which is demountable. The cabinet has walls which are joined edge to edge by joiner elements. At the apex of each intersection of the walls there is a retainer. The retainers prevent the joiner elements from being removed. One of the retainers which is the last to be installed when the cabinet is assembled is lockable. This lockable retainer needs to be unlocked and removed before any of the other joiner elements and retainer elements can be removed so as to disassemble or demount the cabinet.  
           [0003]    The cabinet according to WO 99/08575 has been extremely successful especially in the museum environment. One of the attributes of the cabinet is that it can be assembled around the object or objects to be displayed. This is particularly useful where the object is large and would otherwise be difficult to engage an assembled cabinet over the object(s). Thus the object can be placed on one side of the cabinet and then the remainder of the cabinet assembled around the object by progressively positioning the sides and top panels edge to edge, insertion of the joiner elements and the retainers.  
           [0004]    The cabinet of WO 99/08575 also exhibits good strength characteristics when assembled. This is despite the fact that the walls are joined edge to edge by a joiner element of overall small cross sectional dimensions.  
           [0005]    According to the invention of WO 99/08575 the edges of the walls are profiled and the joiner element has a cross sectional profile which is slid on to the adjacent profiled wall edges (the panels being located at right angles to one another). As a result the joiner element couples the profiled edges together to provide a sound and secure manner. This has worked successfully, however, we have now developed further the joiner element and the profiles of the edges such that assembly of the joint between panels is further facilitated by making it easier to slide the joiner element on to the profiled edges of the adjacent wall panels. Also a stronger join is achieved.  
         SUMMARY OF THE INVENTION  
         [0006]    Broadly in one aspect of the invention there is provided a joint arrangement between adjacent edges of two structural elements the joint arrangement including a joiner element which has projections, each engageable in a recess, groove or the like in a respective of each of the structural elements, the joiner element further having a spine means which in an assembled join between the structural elements engages between edge portions of the structural elements.  
           [0007]    According to a second broad aspect of the invention provides a joint arrangement between adjacent profiled edges of two structural elements, the joint arrangement including an elongate joiner element slidingly engaged with each of said profiled edges, the joiner element having a pair of longitudinally extending projections, each engaged in a longitudinal groove which extends inwardly from a face surface of a respective of the structural elements, the joiner element further including a spine which locates between opposing parts of the profiled edges of the structural elements, said spine having a distal end with a pair of lateral projections each engaged in a groove in a respective of the profiled edges. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is a cross sectional view of a pair of panel elements joined together by a joiner element,  
         [0009]    [0009]FIG. 2 is a similar view but of an alternative embodiment where a more angular joiner element is used,  
         [0010]    [0010]FIG. 3 is a perspective view of a retainer suitable for use with the arrangement shown in FIG. 2,  
         [0011]    FIGS.  4 - 7  are further views of the retainer as shown in FIG. 3,  
         [0012]    [0012]FIG. 8 is a view similar to FIGS. 1 and 2 but showing yet a further form of the invention, and  
         [0013]    [0013]FIG. 9 is a view similar to FIG. 2 but showing how panels or elements of different cross-sectional thickness can be joined together by a joiner element. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]    The following describes and illustrates particular embodiments to the present invention. It will be appreciated by those skilled in the art that other variations and combinations in shape and configuration may be possible without departing from the scope of the invention.  
         [0015]    The content of WO 99/08575 is hereby incorporated by way of specific reference.  
         [0016]    In its simplest form a demountable structure to which the joint arrangement of the present invention applies will be described as a cabinet. The cabinet can comprise a plurality of side walls, a bottom or base wall and a top wall as is disclosed in WO 99/08575. The panel members are joined edge to edge at their peripheral edges by elongate joiner elements, there being one joiner element for each pair of adjacent edges as is described in WO 99/08575. The present invention thus relates specifically to the form and construction of the edges of the panel members and the joiner element. For this reason the drawings accompanying the present specification relate to these aspects of construction.  
         [0017]    [0017]FIG. 1 shows in cross section a part length of each of panels  10  and  11 . The panels are in the illustrated arrangement located in planes which are right angles to one another. The panels  10  and  11  in the preferred form are manufactured from acrylic sheet with the side edges profiled to have an edge profile of the form illustrated.  
         [0018]    In the drawings panels  10  and  11  are shown as physically contacting each other at interface  13 . This interface is for the purposes of illustration, thus it is shown somewhat exaggerated in its length. The interface may be extremely small or may not even exist i.e. the opposing surfaces which form the interface  13  may actually be spaced apart so that no physical contact occurs.  
         [0019]    In the arrangement shown in FIG. 1 the outer surface  14  of the joiner element  12  is curved so as to provide a curved transition from the outer surface of panel  10  to the outer surface of panel  11 . However, with the arrangement shown in FIG. 2 the joiner element  12  is of a more angular cross section at its outer surface where a first surface  15  extends parallel to the outer surface of panel  10  and a second surface  16  extends parallel to the outer surface of panel  11 . The actual physical external appearance of the joiner element  12  could take on other appearances such as a plurality of facets or a more complex curved shape.  
         [0020]    Projecting inwardly (relative to outer surfaces  14  or  15  and  16  as the case may be) are a pair of ribs  17  and  18  which engage in corresponding recesses, grooves, channels or the like  19  and  20  formed in the profiled edge  21  of each panel. In contrast to the grooves used in the edge profiling of WO 99/08575 these grooves are shallow and therefore do not provide a profiling where damage, breakage etc. to the profile edge is a possibility.  
         [0021]    Projecting inwardly from the inside surface of the joiner element  12  is a major spine  22  and a minor spine  23 . This arrangement of two separate spines has been adopted so that a tube die for extrusion of the joiner element  12  is not required. However, as shown in dotted detail in FIG. 1 the major and secondary spines  22 / 23  can be connected if the joiner element is extruded by using a tube die. With such an arrangement there will effectively be a single spine.  
         [0022]    The major spine  22  extends to an enlarged distal end  24  which provides a pair of outwardly disposed ribs  25  and  26 . These ribs  25  and  26  engage in correspondingly shaped grooves  27  and  28  formed in the respective profiled edges of panels  10  and  11 .  
         [0023]    The major spine  22  is also provided with an indent  29  into which engages a projection  30  formed in the profiled edge of panel  10 . A like projection  31  of panel  11  fits into a shaped portion of the major spine  22  but would if the major and minor spines  22  and  23  were coupled, similarly fit into a recess.  
         [0024]    As can be seen in FIG. 1 the major spine  22  has a flat surface  31  which engages against a flat surface  32  of the edge of the panel  10 . Similarly minor spine  23  engages against flat surface  33  of the edge of panel  10 .  
         [0025]    The joiner element  12  therefore keys onto the profiled edges of panels  10  and  11  as shown in FIG. 1. Thus according to the present invention there is no requirement for face to face contact of the respective edges of panels  10  and  11  in order to obtain a secure a robust joint. Because there is no requirement for deep grooves to accept projections from the joiner element the profiled edges of the acrylic panels are not prone to damage or failure. Furthermore, the high degree of accuracy required to ensure the interface between the edges of the panels as required in WO 99/08575 is no longer a requirement.  
         [0026]    Because the panels  10  and  11  of the present invention do not need to fit face to face as an interface (e.g. such as interface  13 ) the panels  10  and  11  can, with suitable adjustment of the profiling and the configuration of the joiner element be located at angles other than 900 as illustrated. Also as shown in FIG. 9 panels of unequal thickness can also be joined. This illustrates how the front to back dimension of the panel is not critical to achieving a successful joint.  
         [0027]    It is also possible with the present invention to key the joiner element  12  onto one panel and then slide the other panel onto the joiner element. This results in the possibility of being able to slide one of the panels relative to the remainder of the cabinet after a pair of the retainers are removed from opposed adjacent corners to provide a means of opening the cabinet. Generally one of the retainers would be the lockable retainer. Such an arrangement is shown in FIG. 8 where the spines  22  and  32  are “fatter”. As a result the edges of panels do not overlap thereby permitting the sliding action referred to above to occur.  
         [0028]    In FIGS.  3 - 7  there is shown a retainer for use with the more angular joiner element shown in FIG. 2. As with the joiner elements disclosed in WO 99/08575 this retainer element has a main body  35  which is configured to fit at the corner of the cabinet and provide a smooth transition to the abutting end of a joiner element. A shaft  36  is shaped to fit into openings formed at each corner and a tongue  37  to engage into the space  38  of joiner element  12  in the same manner as disclosed in WO 99/08575. The shaft  36  includes a chamfered surface  39  to facilitate the insertion of the shaft into the opening as a consequence of the outwardly projecting radial projection  40  which as disclosed in WO 99/08575.  
         [0029]    The joining arrangement according to the present invention thus provides a strong joint and obviates the need for edge profiling of the panels in a manner which can either lead to weakness of the joint or be prone to damage. Also a greater degree of accuracy is achieved as face to face engagement of adjacent panels is not required. Furthermore the manner of keying the joiner element onto the profile edges of the panels does facilitate easier fitment of the joiner element to the panels. Also panels of unequal thickness can be joined together.