FRAME MEMBER FOR A SWITCHING CABINET RACK
Field of the Invention
The present invention relates generally to frame members and, in particular, to frame members for racks. Although the present invention will hereafter generally be described with particular reference to switching cabinet racks, it should be appreciated that the frame member of the present invention is not necessarily limited to being used only with switching cabinet racks and that it may also be used with other types of racks.
Background of the Invention
Electrical/electronic power meters, switches, circuit breakers and other electrical/electronic equipment for commercial and industrial installations, houses and other buildings are usually housed inside a switching cabinet located either inside or outside a building. A typical switching cabinet can include side, rear, bottom and/or top walls, together with a door which covers an opening of the cabinet and which is hinged to the cabinet. Opening a door enables the equipment housed in the cabinet to be accessed.
Such switching cabinets are available in many sizes ranging from relatively small cabinets to large wardrobe-sized cabinets which are used in factories, shopping centres, office blocks and other buildings. The large wardrobe-sized cabinets usually include a metal frame (referred to in the art as a "rack"), which maintains the structural integrity of the cabinet. The rack usually includes a plurality of vertical frame members, together with a plurality of horizontal frame members.
The vertical frame members are usually located at the upright corners of the cabinet, and the horizontal frame members usually extend between those vertical frame members at the top and bottom of the cabinet, forming the basis
for the cabinet's four sides. The top, the bottom and three of the sides of the cabinet are usually covered by metal panels to form walls, with the remaining side (normally the front) being covered by a door which is usually hinged to a vertical frame member to provide access to the interior of the cabinet. However, it may also be possible to fix doors to any of the other sides of a cabinet in place of the metal panels. In some situations, multiple of these cabinets are secured together as modules (referred to in the art as "baying") to form a bayed enclosure.
It is often necessary to secure internal components, such as rails, to the vertical and/or horizontal frame members of switching cabinets. These rails, and the fasteners (usually screws or bolts) which are normally used to secure them to the frame members, sometimes protrude beyond the frame members and thus can obstruct the openings between the frame members. In order to overcome this problem, frame members have been developed which include recessed regions for securing the rails, so that the rails and their fasteners do not protrude and do not obstruct the openings between frame members. For example, Australian patent 728174 discloses a prior art switching cabinet having frame members with recessed regions for securing rails thereto, such that the rails and their fasteners do not obstruct the openings of the cabinet.
However, the configuration of the frame member of Australian patent 728174 requires the presence of four rows of fixing apertures, one row in each of the four inward facing (when assembled) walls of the frame member, in order to function effectively in a rack. The need for four such rows of fixing apertures makes the frame member of Australian patent 728174 reasonably complex to form and thus comparatively expensive.
It is an aim of the present invention to provide a comparatively simple and inexpensive frame member that can be used for a switching cabinet rack, to which rails can be secured in a manner that minimises the rails and/or their fasteners obstructing the openings between frame members.
Before turning to a description of the present invention, it is to be appreciated that the above discussion of the background to the present invention is included to explain the context of the present invention. This is not to be taken as an admission that any of the material referred to was published, known, or part of the common general knowledge in Australia (or elsewhere) as at the priority date of any of the claims in this application.
Also before turning to a description of the present invention, it is useful to provide an explanation of some of the terms that will be used to define the spatial relationship of various parts thereof. In this respect, spatial references throughout this specification will generally be based upon an assembled switching cabinet standing generally upright. With this environment as the basis, some parts may then be defined with reference to the "horizontal" and the "vertical", allowing further references to "upper" or "upwardly" and "lower" or "downwardly". Further, it will be understood that a switching cabinet always has an interior, and thus some parts may be defined with directional reference to "inner" or "inwardly" and "outer" or "outwardly" with respect to the interior of the switching cabinet.
Summary of the Invention
The present invention provides a frame member for a switching cabinet rack, the frame member having an outer profile and an inner profile, the inner profile including: (a) a pair of outer walls, the outer walls facing generally inwardly and being perpendicular with respect to each other; and
(b) a pair of adjacent inner walls between the outer walls, the inner walls also facing generally inwardly and being perpendicular to each other, each inner wall including a series of spaced fastening apertures therealong; wherein each inner wall is recessed with respect to the outer wall generally adjacent to it.
It will be appreciated that the recessing of each inner wall with respect to its generally adjacent outer wall permits a rail to be secured to one of the fastening apertures of one of the inner walls of the frame member, without the rail (or its fasteners) projecting beyond the generally adjacent outer wall and into the opening between frame members (when assembled). The depth of the recessing of the inner walls is thus not able to defined without reference to the size and configuration of the rails and fasteners to be used with the frame member of the present invention. In this respect, the depth of the recessing simply needs to be enough to receive a rail and its fasteners such that this result can be achieved.
It will also be appreciated that the above reference to "generally inwardly" is intended to clarify that the inner and 'outer walls of the inner profile need not face, in use, precisely towards the geometric centre of the interior of the assembled switching cabinet rack. Indeed, these walls are likely to face more directly towards an opposing frame member on the other side of the switching cabinet rack, which is nonetheless more towards the interior of the switching cabinet rack rather than the exterior. In this respect, it will actually normally be the outer profile of the frame member that faces, in use, the exterior of the switching cabinet rack.
The inner profile of the frame member of the present invention preferably also includes a pair of intermediate walls, with one intermediate wall between each of the generally adjacent inner and outer walls. In one form, each intermediate wall is generally perpendicular to its adjacent inner and outer wall. In another form, each intermediate wall is inclined obliquely with respect to its adjacent inner and outer wall.
Thus, in the most preferred form, the inner profile of the frame member of the present invention consists of:
(a) a pair of outer walls, the outer walls facing generally inwardly and being perpendicular with respect to each other;
(b) a pair of adjacent inner walls between the outer walls, the inner walls also facing generally inwardly and being perpendicular to each other, each inner wall including a series of spaced fastening apertures therealong; and (c) a pair of intermediate walls, the intermediate walls facing generally inwardly, with one intermediate wall between each generally adjacent inner and outer wall; wherein each inner wall is recessed with respect the outer wall generally adjacent to it.
In this most preferred form, the inner profile of the frame member can thus be said to be generally V-shaped. In this form, the bottom apex of this notional V will, in use, point generally towards the geometric centre of a (square-shaped) switching cabinet rack. Preferably, the frame member will thus be symmetric about a notional diagonal centre line passing through the geometric centre of a (square-shaped) switching cabinet rack.
Given the relationship between frame members that would be expected when assembled to form a rack for a switching cabinet, it will be appreciated that the frame member is likely to be elongate and various walls of the inner profile of the frame member will ordinarily be planar along their entire length. Also, each pairing of adjacent inner and outer walls will ordinarily be substantially parallel (within normal manufacturing tolerances), and will thus be substantially perpendicular (again, within normal manufacturing tolerances) with the other pairing of adjacent inner and outer walls.
Also, it will be appreciated that the frame member will preferably be an integral one-piece member, and thus may be fabricated using any suitable fabrication process and from any suitable material. It is envisaged that the frame member will ordinarily be roll-formed in metal.
The outer profile of the frame member of the present invention may be any suitable configuration. However, it is envisaged that its configuration will be somewhat sympathetic to the configuration of the inner profile, and may indeed at least partially mirror the inner profile. This would ideally result in the frame member being formed as a hollow member. In a preferred form, the outer profile includes a channel which includes a main wall and respective side walls, the main wall and side walls together forming a generally U-shaped channel having a wide mouth. In this form, the main wall of the outer profile is preferably parallel to the intermediate walls of the inner profile, which then links the spatial relationship of the configurations of the outer and inner profiles.
Finally, it will be appreciated that the present invention not only provides a frame member for a switching cabinet rack, but also provides a switching cabinet rack assembled using at least two of the frame members described above. The present invention also provides a kit of parts for a switching cabinet rack, the kit of parts including at least two of the frame members described above.
Description of Preferred Embodiments of the Invention
The present invention will now be described with reference to various preferred embodiments. However, it is to be understood that the following description is being provided simply to illustrate examples of how the inventive concepts generally described above might be implemented. The following discussion of the preferred embodiments is thus not to limit the generality of the above discussion of the invention:
Figure 1 is a perspective of an end portion of a frame member according to a first preferred embodiment of the present invention;
Figure 2 is a plan of the frame member depicted in Figure 1 with a rail secured thereto;
Figure 3 is a perspective of a switching cabinet rack which includes a plurality of frame members of the type depicted in Figures 1 and 2; and
Figure 4 is a perspective of a portion of a frame member according to a second preferred embodiment of the present invention.
Figure 1 and Figure 2 depict an end portion of a frame member 20 according to a first preferred embodiment of the present invention. The frame member 20 has an inner profile 21a and an outer profile 21 b, both of which are referenced only in Figure 2.
The inner profile 21a includes a pair of identical and perpendicular, inwardly facing, planar outer walls 22a, 22b which are spaced apart from each other. In this respect, such a reference to "identical" and "perpendicular" should be understood to be only a general requirement given normal manufacturing tolerances.
A pair of inwardly facing planar inner walls 23a, 23b are located between the outer walls 22a, 22b, with one outer wall 22a generally adjacent to one inner wall 23a and the other outer wall 22b generally adjacent the other inner wall 23b. In this respect, this reference to "generally adjacent" is herein used to permit the presence therebetween of the intermediate walls 27a, 27b described below, whilst still notionally aligning pairings of inner/outer walls (as per the "a" and "b" designations).
The inner walls 23a, 23b are perpendicular to each other, are located adjacent to each other (as opposed to only being generally adjacent to each other), and are thus joined to each other along a common edge 24. The inner walls 23a, 23b are parallel to the outer walls 22a, 22b, but are recessed from the outer walls 22a, 22b by a distance XY as depicted between the dotted lines X and Y. The distance XY will be further described below with reference to the rail 33 and its fastener 34.
Each of the inner walls 23a, 23b includes a series of fastening apertures in the form of keyhole-shaped openings 25 and rectangular-shaped openings 26, which are arranged therealong in an alternating manner. The keyhole-shaped openings 25 are adapted to engage with a screw, while the rectangular-shaped openings 26 are adapted to receive a cage nut such as an M8 cage nut.
Respective planar intermediate walls 27a, 27b join an outer wall 22a, 22b to an inner wall 23a, 23b such that both of the intermediate walls 27a, 27b extend obliquely between an outer wall 22a, 22b and an inner wall 23a, 23b. The intermediate walls 27a, 27b are identical to each other and are coplanar.
Respective planar end walls 28a, 28b are adjacent to one of the outer walls 22a, 22b such that each end wall 28a, 28b is perpendicular to the outer wall 22a, 22b that it is adjacent to. The end walls 28a, 28b are identical to each other and converge towards each other from the outer walls 22a, 22b such that the end walls 28a, 28b are perpendicular to each other.
The outer profile 21 b of the frame member 20 includes a generally U-shaped channel 29 which is located between the end walls 28a, 28b. The channel 29 includes a planar main wall 30, and respective planar side walls 31a, 31b adjacent thereto, which together define the general U-shape of the channel 29 (having a relatively wide-open mouth). The side walls 31a, 31 b are also identical to each other and converge towards each other from the end walls 28a, 28b. Each side wall 31a, 31b is thus parallel with a respective outer wall 22a, 22b, and also with a respective inner wall 23a, 23b. As can be seen, in this form, the main wall 30 is also arranged to be parallel to each of the intermediate walls 27a of the inner profile 21a.
The frame member 20, and thus its inner profile 21a and its outer profile 21b, are symmetric about a notional diagonal centre line passing through the geometric centre of a square-shaped switching cabinet rack, that notional
diagonal centre line being represented in Figure 2 as a line of symmetry 32 which bisects the main wall 30 and intersects the common edge 24.
The frame member 20 is fabricated from a metal blank using a roll-forming fabrication process.
With particular reference to Figure 2, a rail 33 extends laterally from the inner profile 21a of the frame member 20 and is secured to one of the inner walls 23b with a fastener such as a screw 34, in a manner such that the rail 33 and the screw 34 do not protrude past the outer wall 22b as depicted by the dotted line Y. Therefore, if the outer wall 22b defines a border of an opening, when the frame member 20 is assembled to form a switching cabinet rack (such as the switching cabinet rack in Figure 3), the rail 33 and the screw 34 will not protrude into and obstruct the opening by virtue of the inner wall 23b being recessed a suitable distance with respect to the outer wall 22b. In relation to the distance XY, it will thus be appreciated that this distance will be dependent upon the likely size of the rails 33 and the screws 34, and thus will likely be different in different design situations.
Of course, it will also be apparent that a rail 33 may be secured to the other inner wall 23a such that the rail 33 and the screw 34 do not protrude past the other outer wall 22a.
Referring now to Figure 3, a switching cabinet rack 40 includes a rectangular lower frame 41 and a rectangular upper frame 42, the upper frame 42 being located above the lower frame 41 and being identical thereto. Both the lower frame 41 and the upper frame 42 include four identical horizontal frame members 43 which are joined to each other by corner connectors 44. Apart from differences in length, the horizontal frame members 43 are the same configuration as the frame member 20 shown in Figures 1 and 2.
Four parallel and identical vertical frame members 45 extend between the lower frame 41 and the upper frame 42, and are joined to the corner connectors 44 such that the lower frame 41 and the upper frame 42 are thereby connected to each other. Again apart from differences in length, the vertical frame members 45 are also the same configuration as the frame member 20 shown in Figures 1 and 2. Therefore, for convenience, features of the horizontal and vertical frame members 43, 45 are referenced using the same reference numbers which were used to reference the same features of the frame member 20.
The outer profiles (and thus, amongst other things, the channels 29) of the horizontal and vertical frame members 43, 45 face generally outwardly with respect to the interior of the switching cabinet rack 40. The inner profiles (and thus, amongst other things, the outer and inner walls 22a, 22b and 23a, 23b) of the horizontal and vertical frame members 43, 45 face generally inwardly with respect to the interior of the switching cabinet rack 40.
In terms of the alignment of the various frame members with each other in the assembled switching cabinet rack 40, the following will be apparent from Figure 3: ■ one of the inner walls 23b (not all of which are marked in Figure 3) of each horizontal frame member 43 of the lower frame 41 is coplanar with one of the inner walls 23b of each of the other horizontal frame members 43 of the lower frame 41 , and one of the inner walls 23b (again, not all of which are marked in Figure 3) of each horizontal frame member 43 of the upper frame 42 is coplanar with one of the inner walls 23b of each of the other horizontal frame members 43 of the upper frame 42; ■ the other inner wall 23a of each horizontal frame member 43 of the lower frame 41 is coplanar with the other inner wall 23a of a respective horizontal frame member 43 of the upper frame 42; and ■ each of the inner walls 23a of each vertical frame member 45 is coplanar with one of the inner walls 23b of a respective one of the other vertical frame members 45.
Rails 46 can thus be secured to the inner walls 23a, 23b of the vertical frame members 45 with screws or bolts such that the rails 46 and the screws or bolts do not protrude into the openings defined between the various outer walls of the vertical frame members 45, as outlined above. The openings may, for example, be door openings. In this respect, wall panels and/or one or more doors may be secured to the various sides of the rack 40 so as to thereby form an enclosed switching cabinet.
Illustrated in Figure 4 is a second embodiment of a frame member according to the present invention. As can be seen however, the only difference between this second embodiment and the first embodiment described and illustrated above, is in the configuration of the fastening apertures along the length of a frame member. In this respect, the apertures 25 and 26 shown in Figures 1 and
2 have been replaced with circular fastening apertures 25' and rectangular fastening apertures 26'.
It will be appreciated by those skilled in the art that variations and modifications to the invention described herein will be apparent without departing from the spirit and scope thereof. The variations and modifications as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth.