Abstract:
An enclosure, suitable for use in a telecommunications or data communications network, is of generally cuboidal shape. The enclosure includes an upper frame assembly that extends across an upper region of the enclosure, a lower frame assembly that extends across a lower region of the enclosure, and first, second, third and fourth upright frame members connectible between the upper frame assembly and the lower frame assembly in a plurality of different positions in the regions of the sides of the enclosure to provide different configurations of the enclosure and upright mounting angles. In a first configuration the first and second upright frame members are disposed in a front region of the enclosure at opposite sides thereof and the third and fourth upright frame members are disposed in a rear region of the enclosure at opposite sides thereof.

Description:
TECHNICAL FIELD  
       [0001]    This invention relates generally to enclosures and, in particular, to enclosures suitable for use in a telecommunications or a data communications network and to methods of assembling enclosures. Such enclosures are commonly used to house a variety of electronic and cable connecting equipment. 
       BACKGROUND OF THE INVENTION 
       [0002]    Enclosures are commonly provided to house a variety of computer, telecommunications and other data equipment to which a multiplicity of cables are connected. Whilst it is desirable to enclose the equipment to protect it and also to protect persons from contact with it, it is also desirable to be able to gain as much access as possible to the equipment in the enclosure. 
         [0003]    In WO 99/48305 this problem is addressed and an enclosure is described which has a novel skeleton frame structure including a pair of upright frame members at the centres of the sides of the enclosure and top and bottom rectangular frame assemblies secured to opposite ends of the frame members. That arrangement contrasts with a more standard arrangement in which four upright frame members are provided in the regions of the corners of an enclosure and provides certain advantages over the more standard arrangement. Upright mounting angles are provided in addition to the frame members. 
         [0004]    Enclosures are used in a wide variety of applications and different forms of enclosure suit different applications. Thus an enclosure of the kind described in WO 99/48305 may be of benefit in one application because, for example, the placing of the upright frame members away from the front and back of the enclosure makes access to the front and back easier, whilst the more standard arrangement with upright frame members in the corner regions of the enclosure may be of benefit in another application because, for example, particular strength is required at the front or back of the frame. 
         [0005]    It is an object of the invention to provide an improved enclosure and an improved method of assembling an enclosure. 
       SUMMARY OF THE INVENTION 
       [0006]    According to the invention there is provided an enclosure suitable for use in a telecommunications or data communications network, the enclosure being of generally cuboidal shape, including an upper frame assembly that extends across an upper region of the enclosure, a lower frame assembly that extends across a lower region of the enclosure, first, second, third and fourth upright frame members connectible between the upper frame assembly and the lower frame assembly in a plurality of different positions in the regions of the sides of the enclosure to provide different configurations of the enclosure, and upright mounting angles suitable for mounting equipment for use in a telecommunications or data communications network, the enclosure being able to be assembled in a first configuration in which the first and second upright frame members are disposed in a front region of the enclosure at opposite sides thereof and the third and fourth upright frame members are disposed in a rear region of the enclosure at opposite sides thereof, and the enclosure also being able to be assembled in a second configuration in which the first, second, third and fourth upright frame members are disposed in regions spaced from the front and rear regions of the enclosure. 
         [0007]    By providing an enclosure that can be assembled with upright frame members in different positions, a user is able to select a particular frame configuration most suitable for a particular application. For example, the first configuration might be chosen for maximum strength of the frame, whilst the second configuration might be chosen to enhance access to the front and rear of the frame. The frame may be a skeleton frame. The upright frame members preferably provide at least the major structural connection between the upper and lower frame assemblies. 
         [0008]    It should be noted that according to the invention it is the upright frame members themselves that are able to be assembled in different positions. The upright mounting angles may also be able to be moved and, indeed, commonly are able to be moved. Preferably the upright mounting angles can be moved independently of the upright frame members. Preferably the upright mounting angles are able to be moved forwardly and rearwardly in the frame and more preferably are continuously adjustable to any position within their range of movement. 
         [0009]    Preferably all of the upright frame members are able to be assembled in different positions. This enables the frame to be provided with good versatility. 
         [0010]    In one form of the second configuration of the enclosure, the first and third frame members may be adjacent to one another; similarly, the second and fourth frame members may be adjacent to one another; in this case the frame members may be alongside one another and in contact with one another or virtually in contact with one another. Another possible form of the second configuration is one in which there is an elongate vertical gap between the first and third frame members and another elongate vertical gap between the second and fourth frame members. Preferably each gap, if there is one, is a narrow gap, the width of each gap extending along a respective side of the enclosure. The enclosure may be able to be assembled in either or both forms of the second configuration. 
         [0011]    Preferably, in the second configuration of the enclosure, the first, second, third and fourth frame members are disposed approximately midway between the front and rear of the enclosure. More preferably the first and third members are symmetrically disposed on opposite sides of a vertical plane midway between the front and rear of the enclosure. 
         [0012]    The enclosure is preferably able to be assembled in a third configuration in which the first and second upright frame members are disposed in a front region of the enclosure and the third and fourth upright frame members are disposed in a region spaced from the front and rear regions of the enclosure. In the third configuration of the enclosure, the third and fourth upright frame members are preferably disposed approximately midway between the front and rear of the enclosure. In the third configuration of the enclosure access to the rear of the enclosure can be facilitated. Similarly, the enclosure is preferably able to be assembled in a fourth configuration in which the third and fourth upright frame members are disposed in a rear region of the enclosure and the first and second upright frame members are disposed in a region spaced from the front and rear regions of the enclosure. In the fourth configuration of the enclosure, the first and second upright frame members are preferably disposed approximately midway between the front and rear of the enclosure. In the fourth configuration of the enclosure access to the front of the enclosure can be facilitated. It should be understood that in the third and fourth configurations, the positions of the first and second upright members on the one hand, and the positions of the third and fourth upright members on the other hand, can be interchanged. 
         [0013]    The enclosure is preferably able to be assembled in a fifth configuration in which the first and second upright frame members are disposed at opposite sides of the enclosure and the third and fourth upright frame members are disposed at opposite sides of the enclosure, with the first and third frame members on one side of the enclosure and the second and fourth frame members on the opposite side of the enclosure, and with the spacing of the first and third frame members different from the spacing of the second and fourth frame members. In the fifth configuration, the first frame member is preferably disposed in a front region of the enclosure, the third frame member is preferably disposed in a rear region of the enclosure, and the second and fourth frame members are preferably disposed in regions spaced from the front and rear regions of the enclosure. In the fifth configuration of the enclosure, the second and fourth upright frame members are preferably disposed approximately midway between the front and rear of the enclosure. A configuration of this kind may for example be employed together with another enclosure placed alongside in a configuration that is a mirror image of the first. In that case the two enclosures together may define a double width enclosure with upright frame members at each of its four corners but with no vertically extending obstruction in the middle of the front and back of the enclosure; if desired one or more further enclosures may be fitted between said two enclosures, with those one or more enclosures being in the second configuration. 
         [0014]    Some or all of the upright frame members may be of the same construction, allowing them to be interchanged. 
         [0015]    The enclosure may further include fifth and sixth upright frame members, and the enclosure may be able to be assembled in the first configuration with the fifth and sixth upright frame members disposed in regions spaced from the front and rear regions of the enclosure. In this configuration of the enclosure, the fifth and sixth upright frame members are preferably disposed approximately midway between the front and rear of the enclosure. 
         [0016]    It should be understood that where reference is made, for example, to the fourth or fifth configurations that should not be taken as implying that all the other configurations of lower number are necessarily possible; for example, it is within the scope of the invention for the enclosure to be able to be assembled in the fourth configuration but not the third, or to be able to be assembled in the fifth and sixth configurations but not the third and fourth. 
         [0017]    In an enclosure for use in a telecommunications or data communications network it is conventional to provide vertically extending mounting angles for mounting electrical equipment such as cable connecting equipment and computer equipment such as modems and servers. The mounting angles may be designed according to any required standard; for example, they may be IEC 297-1 mounting angles or ETSI 300-119 Part 3 mounting angles or mounting angles according to another telecommunications standard. The mounting angles are preferably secured to the upper and lower frame assemblies. It is also possible for the mounting angles to be supported partly or wholly by the upright frame members. Whilst the mounting angles may contribute to a modest extent to the structural strength of the frame, it is preferable that the strength is provided principally by the upright frame members. The mounting angles are preferably able to be removed without destroying the structural integrity of the frame. 
         [0018]    The positions of the mounting angles are preferably adjustable and more preferably the mounting angles are preferably secured to the frame in a manner that enables their position to be adjusted continuously between extreme forward and rearward positions. 
         [0019]    The upper and lower frame assemblies preferably include frame parts extending substantially horizontally along the sides of the frame. Each frame assembly may be of generally rectangular shape. Preferably each frame assembly is of generally rectangular shape. The assemblies may comprise frame parts around the peripheries of the assemblies only. In embodiments of the invention described below, each frame assembly comprises a pair of horizontal frame members along the sides of the assembly and a pair of horizontal frame members along the front and back of the assembly. The horizontal frame members may be connected together at their corners, for example by bolts. 
         [0020]    Preferably the upright frame members are connectible, for example by bolts, to the frame parts at a multiplicity of discrete positions along the frame parts. Another possibility is for the upright frame members to be connectible at any point along the frame parts to allow continuous adjustment of their positions. 
         [0021]    In an embodiment of the invention described below, the frame parts have channels extending along their lengths for receiving ends of the upright frame members. 
         [0022]    Whilst the product of the invention is described as an enclosure, it should be understood that it is not essential for the interior to be enclosed on all sides. One or more sides may be partly or fully open. It is preferred, however, that the enclosure further includes one or more panels providing a cover for at least a part of a face of the enclosure. The panels are preferably mounted on the upper and lower frame assemblies. That facilitates the provision of an enclosure that can be assembled readily in the first or second, or other, configurations. The panels preferably include one or more side panels covering over at least a part of the side of the enclosure. Panels may be provided over all six faces of the enclosure. The panels may include door panels. 
         [0023]    According to the invention there is provided a method of assembling an enclosure for use in a telecommunications or data communications network, the method including the steps of connecting first, second, third and fourth upright frame members in upright positions extending between upper and lower frame assemblies extending across upper and lower regions of the enclosure respectively, wherein the positions at which the upright frame members are connected to the upper and lower frame assemblies is chosen to provide a selected one of a plurality of desired configurations of enclosure, the desired configurations including a first configuration in which the first and second upright frame members are disposed in a front region of the enclosure at opposite sides thereof and the third and fourth upright frame members are disposed in a rear region of the enclosure at opposite sides thereof, and a second configuration in which the first, second, third and fourth upright frame members are disposed in regions spaced from the front and rear regions of the enclosure. 
         [0024]    The enclosure may initially be assembled in a chosen configuration and may always be used in that configuration, but it is also possible to change the configuration of the enclosure during its life. Thus, the method may further include the steps of assembling the enclosure in a chosen one of the plurality of configurations, subsequently dissembling the enclosure and reassembling the enclosure in another chosen one of the plurality of configurations. 
         [0025]    The enclosure assembled by the method of the invention may take any of the forms defined above. 
         [0026]    It will be appreciated that the enclosure of the invention and the assembly method of the invention as described herein are closely related and that therefore essential or preferred features of one may, unless indicated otherwise or clearly inappropriate, be incorporated into the other. Thus, features described above in respect of the enclosure of the invention may be incorporated into the assembly method of the invention and vice versa. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    By way of example embodiments of the invention will now be described with reference to the accompanying schematic drawings, of which: 
           [0028]      FIG. 1A  is an isometric view of an enclosure frame with frame members in a first configuration and mounting angles in one configuration; 
           [0029]      FIG. 1B  is an isometric view of the enclosure frame of  FIG. 1A  with frame members in the first configuration and mounting angles in another configuration; 
           [0030]      FIG. 2A  is an isometric view of the enclosure frame of  FIG. 1A  with frame members in a second configuration and mounting angles in one configuration; 
           [0031]      FIG. 2B  is an isometric view of the enclosure frame of  FIG. 2A  with frame members in the second configuration and mounting angles in another configuration; 
           [0032]      FIG. 3A  is an isometric view of the enclosure frame of  FIG. 1A  with frame members in a third configuration and mounting angles in one configuration; 
           [0033]      FIG. 3B  is an isometric view of the enclosure frame of  FIG. 3A  with frame members in the third configuration and mounting angles in another configuration; 
           [0034]      FIG. 4A  is an isometric view of the enclosure frame of  FIG. 1A  with the frame members in a fourth configuration and mounting angles in one configuration; 
           [0035]      FIG. 4B  is an isometric view of the enclosure frame of  FIG. 4A  with frame members in the fourth configuration and mounting angles in another configuration; 
           [0036]      FIG. 5A  is an isometric view of the enclosure frame of  FIG. 1A  with the frame members and mounting angles in the same configuration as in  FIG. 1A , but with two additional upright frame members; 
           [0037]      FIG. 5B  is an isometric view of the enclosure frame of  FIG. 5A  with the members in the same configuration as in  FIG. 5A , but with the mounting angles in the same configuration as in  FIG. 1B ; 
           [0038]      FIG. 6A  is an isometric view of the enclosure frame as shown in  FIG. 1B , showing in an exploded view side panels for fitting to the frame; 
           [0039]      FIG. 6B  is an isometric view of the enclosure frame as shown in  FIG. 2A , showing in an exploded view side panels for fitting to the frame; 
           [0040]      FIG. 6C  is an isometric view of the enclosure frame as shown in  FIG. 3A , showing in an exploded view side panels for fitting to the frame; 
           [0041]      FIG. 7A  is an isometric view showing a first form of fastening system for fastening mounting angles to the frame; and 
           [0042]      FIG. 7B  is an isometric view similar to  FIG. 7A  but showing a second form of fastening system for fastening mounting angles to the frame. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0043]    Referring first to  FIG. 1A , there is shown an enclosure frame generally comprising an upper frame assembly  1 , a lower frame assembly  2 , and four upright frame members  3 ,  4 ,  5  and  6  each connected between the upper and lower frame assemblies  1 ,  2 . The upper frame assembly  1  is rectangular and comprises a pair of horizontal side frame members  7  and  8 , a front horizontal frame member  9  and a rear horizontal frame member  10 . Similarly, the lower frame assembly  2  is rectangular and comprises a pair of horizontal side frame members  11  and  12 , a front horizontal frame member  13  and a rear horizontal frame member  14 . Each of the side frame members  7 ,  8  is formed with a channel  15  in its bottom face, extending along the whole length of the member. Similarly, each of the side frame members  11 ,  12  is formed with a channel  15  in its top face, extending along the whole length of the member. In  FIG. 1A  the channels in the side frame members  11 ,  12  are visible, but not the channels in the frame members  7 ,  8 . 
         [0044]    In a first configuration of the frame, shown in  FIG. 1A , the first upright frame member  3  and the second upright frame member  4  are at the front of the frame, with their top ends received in the front ends of the channels  15  in the horizontal side frame members  7  and  8  and their bottom ends received in the front ends of the channels  15  in the horizontal side frame members  11  and  12 . Similarly the third upright frame member  5  and the fourth upright frame member  6  are at the rear of the frame, with their top ends received in the rear ends of the channels  15  in the horizontal side frame members  7  and  8  and their bottom ends received in the rear ends of the channels  15  in the horizontal side frame members  11  and  12 . 
         [0045]    Also shown in  FIG. 1A  are a first pair of mounting angles  23 ,  24  towards the front of the enclosure and a second pair of mounting angles  25 ,  26  towards the rear of the enclosure. The mounting angles  23  to  26  are secured to the inner sides of the horizontal side frame members  7 ,  8 ,  11  and  12 . Such mounting angles are for mounting equipment for use in a telecommunications or data communications network. In an enclosure for use in a telecommunications or data communications network it is conventional to provide such vertically extending mounting angles for mounting electrical equipment (not shown) such as cable connecting equipment and computer equipment such as modems and servers. The mounting angles may be arranged according to any required standard; for example, they may be IEC 297-1 mounting angles or ETSI 300-119 Part 3 mounting angles or mounting angles according to another telecommunications standard. Whilst the mounting angles  23  to  26  will contribute to a modest extent to the structural strength of the frame when they are secured in place, the strength of the frame is provided principally by the upright frame members. The mounting angles can be removed without destroying the structural integrity of the frame. 
         [0046]    The fasteners used to fasten the upright frame members  3 ,  4 ,  7 ,  8  to the side frame members  7 ,  8 ,  11  and  12  may be of any suitable kind. Similarly, the fasteners used to fasten the mounting angles  23  to  26  to the side frame members may be of any suitable kind. For example, the fasteners may simply comprise bolts, passing through holes in the frame members and mounting angles and nuts fastened tightly on the bolts. Alternatively, more sophisticated fastenings may be employed. 
         [0047]      FIG. 1B  shows the frame of  FIG. 1A  with the upright frame members  3 ,  4 ,  5  and  6  in the same position as in  FIG. 1A , but with the mounting angles  23  to  26  in different positions. In  FIG. 1B  the first pair of mounting angles  23 ,  24  are at the front of the frame just behind the frame members  3  and  4 , whilst the second pair of mounting angles  25 ,  26  are at the rear of the frame just in front of the frame members  5  and  6 . 
         [0048]      FIG. 2A  shows a second configuration of the frame in which the upright frame members  3 ,  4 ,  5  and  6  are moved from the corners of the enclosure to the middle of the sides of the enclosure. In  FIG. 2A , the upright frame member  3  and the upright frame member  5  are immediately adjacent to one another with no gap between them and, similarly, the upright frame member  4  and the upright frame member  6  are immediately adjacent to one another with no gap between them. The interface of the frame members  3  and  5  and the interface of the frame members  4  and  6  lie in a vertical plane equispaced from the front and rear of the enclosure frame. 
         [0049]    In  FIG. 2A , the first pair of mounting angles  23 ,  24  is provided at the front of the enclosure, and the second pair of mounting angles  25 ,  26  is provided at the rear of the enclosure. 
         [0050]      FIG. 2B  shows the frame of  FIG. 2A  with the upright frame members  3 ,  4 ,  5  and  6  in the same position as in  FIG. 1A , but with the mounting angles  23  to  26  in different positions. In  FIG. 2B , the first pair of mounting angles  23 ,  24  are moved rearwardly from their positions in  FIG. 2A  and are just in front of the frame members  3  and  4 , whilst the second pair of mounting angles  25 ,  26  are moved forwardly from their positions in  FIG. 2A  and are just behind the frame members  5  and  6 . 
         [0051]    As will be understood, another possible arrangement of frame members, very similar to that of  FIG. 2B , would be to provide a narrow gap between the upright frame members  3  and  5  and, similarly, a narrow gap between the upright frame members  4  and  6 . The slight spacing apart of the frame members may increase the structural strength of the enclosure and also provides a central opening through which cables can be passed if desired. 
         [0052]      FIG. 3A  shows an arrangement in which one pair of frame members are connected between the mid-points of the sides of the upper and lower frame assemblies  1  and  2 , whilst the other pair of frame members are connected at the front or rear of the enclosure. In this third configuration of the enclosure shown in  FIG. 3A , the upright frame members  3  and  4  are at the front of the enclosure and the upright frame members  5  and  6  are midway between the front and rear of the enclosure. Of course another, very similar, configuration is one in which the upright frame members  3  and  4  are midway between the front and rear of the enclosure and the upright frame members  5  and  6  are at the rear of the enclosure. That is referred to herein as a fourth configuration. 
         [0053]    In  FIG. 3A  the first pair of mounting angles  23 ,  24  is provided at the front of the enclosure immediately behind the front frame members  3  and  4  and the second pair of mounting angles  25 ,  26  is provided at the rear of the enclosure. 
         [0054]      FIG. 3B  shows the frame of  FIG. 3A  with the upright frame members  3 ,  4 ,  5  and  6  in the same position as in  FIG. 1A , but with the mounting angles  23  to  26  in different positions. In  FIG. 3B , the first pair of mounting angles  23 ,  24  are moved rearwardly from their positions in  FIG. 3A  and are midway between the first pair of frame members  3  and  4  and the second pair of frame members  5  and  6 , whilst the second pair of mounting angles  25 ,  26  are moved forwardly from the rear of the frame to positions just behind the second pair of frame members  5  and  6 . 
         [0055]    The configurations described with reference to  FIGS. 1A to 3B  are all symmetrical about a central vertical plane equispaced from the two opposite sides of the enclosure.  FIG. 4A  shows a fourth configuration where there is no such symmetry. Whilst the upright frame member  4  is at the front of the enclosure and the upright frame member  6  at the rear of the enclosure on the same side as the upright frame member  4 , the upright frame member  3  and the upright frame member  5  are arranged as in  FIG. 2A  on the opposite side of the enclosure midway between the front and rear of the enclosure. 
         [0056]    In  FIG. 4A , the first pair of mounting angles  23 ,  24  is provided at the front of the enclosure with the mounting angle  24  just behind the frame member  4 , and the second pair of mounting angles  25 ,  26  is provided at the rear of the enclosure with the mounting angle  26  just in front of the frame member  6 . 
         [0057]      FIG. 4B  shows the frame of  FIG. 4A  with the upright frame members  3 ,  4 ,  5  and  6  in the same position as is in  FIG. 4A , but with the mounting angles  23  to  26  in different positions. In  FIG. 4B  the first pair of mounting angles  23 ,  24  are moved rearwardly from their positions in  FIG. 4A  such that the mounting angle  23  is just in front of the frame member  3  with the mounting angle  24  opposite the mounting angle  23 , whilst the second pair of mounting angles  25 ,  26  are moved forwardly from their positions in  FIG. 4A  such that the mounting angle  25  is just behind the frame member  5  with the mounting angle  26  opposite the mounting angle  25 . 
         [0058]      FIG. 5A  shows the upright frame members  3 ,  4 ,  5  and  6  connected in the same position as in  FIG. 1A , and the mounting angles  23  to  26  connected in the same positions as in  FIG. 1A , but with two additional upright frame members  20  and  21  provided. The additional frame members  20  and  21  are positioned on opposite sides of the enclosure midway between the front and rear of the enclosure in  FIG. 5A . 
         [0059]      FIG. 5B  shows the frame of  FIG. 5A  with the upright frame members  3 ,  4 ,  5 ,  6 ,  20  and  21  in the same position as in  FIG. 5A , but with the mounting angles  23  to  26  in different positions. In  FIG. 5B  the mounting angles are in the position shown in  FIG. 1B . Thus the first pair of mounting angles  23 ,  24  are at the front of the frame just behind the frame members  3  and  4 , whilst the second pair of mounting angles  25 ,  26  are at the rear of the frame just in front of the frame members  5  and  6 . 
         [0060]    It will be understood that in the embodiments described the upright frame members  3 ,  4 ,  5 ,  6 ,  20  and  21  are all interchangeable. It should also be understood that whilst various configurations of frame members and mounting angles have been shown and described, many other configurations can also be adopted. 
         [0061]    In the drawings only the skeleton frame of each configuration of enclosure is shown. It should be understood that panels, which may include hinged door panels, may be connected to the upper and lower frame assemblies  1 ,  2 . WO 99/48305 describes such arrangements and also other features that may be incorporated in the enclosure of the present invention and the contents of that specification are incorporated herein by reference. 
         [0062]      FIG. 6A  shows how side panels may be fitted to the frame when the upright frame members  3  to  6  are in the positions shown in  FIGS. 1A and 1B . In  FIG. 6A  the mounting angles  23  to  26  are shown in the positions shown in  FIG. 1B , but of course it is also possible for them to be in other positions, including but not limited to the positions shown in  FIG. 1A . 
         [0063]    In  FIG. 6A  the side panels shown comprise two side panels  31  and  32  at one side of the frame and door panels  33  and  34  at the opposite ends of the frame. It should be understood that two further side panels would normally be provided on the opposite side of the frame to the panels  31  and  32 , but those are not shown in  FIG. 6A . Top and/or bottom panels may also be provided. 
         [0064]    The panels  31  and  32  have widths such that when placed side-by-side they can just be fitted between the frame members  4  and  6 . 
         [0065]      FIG. 6B  shows the same parts as  FIG. 6A , but in this case the frame members  3  to  6  are arranged in the configuration shown in  FIGS. 2A and 2B  with the mounting angles  23  to  26  shown in the positions shown in  FIG. 2A . In this configuration, the side panels  31  and  32  are disposed on opposite sides of and immediately adjacent to the upright frame members  4  and  6  which are immediately adjacent to one another. 
         [0066]      FIG. 6C  shows the same parts as  FIGS. 6A and 6B , but in this case the frame members  3  to  6  are arranged in the configuration shown in  FIGS. 3A and 3B  with the mounting angles  23  to  26  shown in the positions shown in  FIG. 3A , but with the enclosure frame viewed from the opposite side to  FIG. 3A . In this configuration, the side panel  31  is disposed between the upright frame members  3  and  5  and the side panel  32  is disposed immediately to the rear of the frame member  5 . 
         [0067]    It will be understood that the arrangements of panels shown in  FIGS. 6A to 6C  are merely examples of arrangements that can be adopted. In the case of all the examples of  FIGS. 6A to 6C  it would often be desirable to supply two further side panels opposite the panels  31  and  32 , and top and bottom panels might also be provided. In the case of an offset arrangement of the kind shown in  FIGS. 4A and 4B , however, the arrangement of side panels on the opposite sides of the frame would differ in accordance with the different arrangements of the upright frame members. 
         [0068]    A situation where panels might be provided on only one side of an enclosure frame is when two or more frames are connected together side-by-side. It may then be advantageous to omit some or all of the side panels at the interface of adjacent frames. When frames are to be connected together side-by-side, the offset arrangement of frame members shown in  FIGS. 4A and 4B  can be of particular advantage in allowing for one frame arrangement at an exterior side of the interconnected frames and a different frame arrangement at the one or more interior interfaces of the frames. 
         [0069]    Referring now to  FIG. 7A , there is illustrated one particular way of fixing the top of a mounting rail  40  to a side frame member  41 . The mounting rail  40  in  FIG. 7A  might for example be the mounting rail  23  of  FIGS. 1A to 5B  and the side frame member  41  in  FIG. 7A  might for example be the horizontal side frame member  7  in  FIGS. 1A to 5B . As can be seen in  FIG. 7A , the side frame member  41  defines a longitudinal channel  42  in which a square or rectangular bolt head (not visible) of a fastener system can be mounted. The fastener system  43  comprises a bolt having the square or rectangular bolt head referred to immediately above and a shaft which extends inwardly from the bolt head through a hole in the top of the mounting rail  40  and has a screw threaded end portion which is engaged by an internally threaded handle  44 . As will be understood, turning the handle  44  in one direction clamps the mounting rail  40  to the side frame member  41 , whilst turning the handle  44  in the opposite direction releases the clamp and allows the position of the mounting rail  40  relative to the side frame member  41  to be altered by sliding the square or rectangular bolt of the fastener system  43  along the channel  42 . 
         [0070]      FIG. 7B  shows a modified version of the arrangement shown in  FIG. 7A  and corresponding parts are shown by the same reference numerals. In the version of  FIG. 7B , the handle  44  is replaced by a threaded fastener  45  which can be turned by a hex key engaging a hexagonal socket in the fastener. 
         [0071]    Also visible in  FIGS. 7A and 7B  is the channel  15  in which the upright frame members  3  and  5  are received. 
         [0072]    Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims.