GB2231117A

GB2231117A - Framework structure

Info

Publication number: GB2231117A
Application number: GB8907906A
Authority: GB
Inventors: John Keith Batchford
Original assignee: Marconi Co Ltd
Current assignee: BAE Systems Electronics Ltd
Priority date: 1989-04-07
Filing date: 1989-04-07
Publication date: 1990-11-07
Anticipated expiration: 2009-04-07
Also published as: GB8907906D0; GB2231117B

Abstract

A framework structure, comprises tubular posts (7) connected together by a frame (4) having cut-out portions each shaped to accommodate a post (7) and presenting at least one flange (6) engageable and generally conformable with the post. Each post has a slot formed through its wall thereof where it is connected to the frame (1). A fixing block (9) within the post has a slot (10) corresponding to the slot in the post wall. A clamping plate (12) engages flanges (6) and has a portion (14) which extends through the slots in the post wall and in the fixing block (9). A screw (16) urges the portion (14) into engagement with the block (9). <IMAGE>

Description

FRAMEWORK STRUCTURE This invention relates to a framework structure which is particularly useful as a framework for a cabinet for electronic components, for example telecommunications equipment.

Cabinets for electronic equipment have been formed by welding together the framework. Such a construction is both costly, since welding requires preparation of surfaces and subsequent cleaning of the welds, and relatively inflexible in catering for different sizes of cabinet. Another form of construction uses die cast end frames between which uprights are secured. This is again relatively costly and ridigity of the frame is not necessarily guaranteed.

According to one aspect of the invention, a framework structure comprises a plurality of tubular posts connected together by a connecting frame, each post being secured to said frame by fixing means comprising a clamping plate engageable on a portion of the frame, a clamping member located within the post, and means extending through the wall of the post for urging the clamping plate and clamping member together thereby to clamp the said portion of the frame and the wall of the post therebetween.

Preferably the clamping plate has a portion insertable through an aperture in the wall of the post and engageable in a recess in the clamping member. The posts are most suitably of a generally square section, and the aperture may be a slot cut across one corner of the square section. The clamping member may be a block which is a loose sliding fit within the post. The means for urging the plate and the member together is appropriately a threaded screw which can pass through an aperture in the clamping plate and which engages in a correspondingly screw-threaded hole in the clamping member.

The connecting frame may suitably be fabricated from sheet metal, for example aluminium alloy or steel.

The framework structure of the present invention is strong and very rigid and can provide good electrical continuity between the frame and the posts, for earthing purposes.

Typically, the sides and top of the framework are filled with metal panels to form the cabinet. These are usually fastened using screws engaging captured nuts held in perforated mounting strips secured to the posts.

It is often necessary to provide spacers between the metal plates and the mounting strips to ensure correct positioning of the panels, and problems have been experienced in maintaining the spacers in their correct position until the screws are engaged with their captured nuts.

Accordingly, another aspect of the invention provides a fixing arrangement, comprising a supporting strip having a plurality of fixing apertures therein, an internally threaded member located within a holding member having resilient arms extending therefrom engageable with the sides of any of the apertures to hold the threaded member in a predetermined position relative to the aperture, a tubular spacer having an internal circumferential grove adjacent to one end thereof, the ends of the arms of the holding member engaging in the grove to hold the spacer in a predetermined position relative to the threaded member, whereby a bolt or screw may be engaged with the threaded member through the spacer.

Reference is made to the drawings, in which: Figure 1 is a perspective view illustrating the connection between the upper connecting frame and one of the tubular posts; Figure 2 shows the fixing member used in the arrangement of Figure 1; Figure 3 is a sectional plan view on line AA of Figure 1, but with the parts partially assembled; Figure 4 illustrates the components of a fixing arrangement according to a second aspect of the invention; and Figure 5 is a sectional view showing the fixing arrangement of Figure 4 in use.

Referring first to Figure 1, the connecting frame 1 is formed of an upper and a lower flange plates 2 and 3 connected by four channel members 4 using a plurality of spot welds. Each flange plate 2 and 3 is formed with four rectangular corner cut-outs 5 the corners being drawn down to present outward facing flanges 6. The channel members 4 project into the rectangular cut-outs 5 by a very small distance so that the posts bear against the ends of the channel members when secured.

Each post 7, which has a cross section corresponding to the cut-out 5, consists of a square section metal tube having adjacent each end a slot 8 cut diagonally through the wall of the tube across one corner of the square section. A square section clamping block 9 is a loose fit within the tubular post 7 and has a slot 10 cut across one corner of the square section in a position corresponding to the slot 8 in the post 7, as may be seen more clearly from Figure 2. A threaded bore 11 extends from this cut-out 10 diagonally through the clamping block 9.

A clamping plate 12 (Figure 1) is located at each corner internally of the frame 1. Each clamping plate 12 has a generally L-section plan, with a slot 13 extending from one face across the corner to the other face.

The slot 13 has a height very slightly smaller than the height of the slot 8 cut in the tubular post 7. The outer ends of the slot are joined together by a web 14 which extends diagonally across the corner, and is provided with a hole 15 therethrough for receiving a threaded bolt 16. These features may be seen more clearly from Figure 3.

Each clamping block 9 is conveniently provided with a threaded bore 17 extending downwardly from the upper face thereof, into which an eyebolt (not shown) may be screwed to permit the completed frame or cabinet to be lifted.

In use, the post 7 is fitted into the cut-out 5, the clamping plate is positioned inside the fixing frame 1 so as to bear against the internal surfaces of the flanges 6 and so that the web 14 extends through the slot 8 and the slot 10 in the clamping block 9 to bear against the block. The bolt 16 is inserted and tightened to draw the fixing plate and the tubular post together with the flanges 6 and the wall of the post 7 sandwiched therebetween. This holds the posts and frames together with great rigidity.

To permit the attachment of electronic equipment within the framework structure and to permit attachment of side panels to close the structure, punched metal attachment strips (not shown) may be secured to the tubular posts 7 by pop riveting or screwing, for example, as is known with conventional cabinet construction.

Referring now to Figures 4 and 5, a known arrangement of captive nut 40 has a conventional square nut 41 held within a spring metal cage 42 which has two inwardly resiliently deflectable arms 43 the ends of which are bent outwardly to present a retaining lip 44.

In Figure 4 a metal fixing strip 45 having square fixing holes 47 is shown, but the captured nut may be used with any shape of aperture of appropriate dimensions. To secure the nut in the fixing strip 45, the arms are pressed together against the resilience of the metal cage, and against the force of spring strips 46 within the cage which bear against the nut 41, sufficiently to permit the lip portions 44 to pass through the hole 47 in the strip 45. On release, the lip portions 44 retain the captured nut in place.

A spacing sleeve 48 is used to space, for example a panel 49, from the fixing strip 45. To permit the sleeve to be held in place while the panel is positioned and a fixing screw 50 is engaged with the nut 41, the spacer 48 is secured to the captured nut 40 as follows. Internally of the spacing sleeve 48 adjacent to one end, a circumferential groove 51 is formed in the wall of the tube. The captured nut is selected so that the cage is dimensioned to accommodate thicker metal than that of the fixing strip 45, whereby the arms 43 extend through and beyond the hole 47, by a distance corresponding to the spacing of the groove 51 from the end of the spacing sleeve 48. The spacing sleeve can then be secured to the captured nut 40 by again compressing the arms 43 inwardly towards each other, inserting them into the end of the sleeve 48, and pushing the sleeve and the captured nut towards each other until the lip portions 44 enter the groove 51. The resilience of the arms 43, and the action of the spring portions 46, urge the lip portions 44 outwardly in to the groove 51 to ensure that the sleeve 48 is held in place. The panel 49 may then be readily secured in position using the screw 50.

The sleeve 48 may be formed of metal such as aluminium alloy or steel, or of a plastics material, for example, according to the location.

Claims

1. A framework structure, comprising a plurality of tubular posts connected together by a connecting frame, each post being secured to said frame by fixing means comprising a clamping plate engageable on a portion of the frame, a clamping member located within the post and means extending through the wall of the post for urging the clamping plate and clamping member together thereby to clamp the said portion of the frame and the wall of the post therebetween.

2. A framework structure according to Claim 1, wherein the clamping plate has a portion insertable through an aperture in the wall of the post and engageable in a recess in the clamping member.

3. A framework structure according to Claim 2, wherein the posts are of generally square section, and the aperture is a slot cut across one corner of the square section.

4. A framework structure according to Claim 1, 2 or 3, wherein the clamping member is a block which is a sliding fit within the post.

5. A framework structure according to Claim 4, wherein the block has a cut-out portion receiving a portion of the clamping plate through the wall of the post.

6. A framework structure, comprising a plurality of tubular posts connected together by a connecting frame having in the periphery thereof a plurality of cut-out portions each shaped to accommodate a respective post therein and presenting at least one flange engageable and generally conformable with the outer surface of the post, each post having a slot formed through the wall thereof at a position at which the frame is connected to the post, a fixing block within each post, each block being a sliding fit within the post and having a slot therein corresponding to the slot in the post wall, a plurality of clamping plates, each positionable so as to compress the flange or flanges of one of the cut-out portions against the respective post and shaped with a portion which extends through the slot in the post wall and into the slot in the fixing block, and means for urging said portion into engagement with the fixing block.

7. A framework structure, substantially as described with reference to Figures 1, 2 and 3 of the drawings.

8. A fixing arrangement, comprising a supporting strip having a plurality of apertures therein, an internally threaded member located within a holding member having resilient arms extending therefrom engageable with the sides of any of the apertures to hold the threaded member in a predetermined position relative to the aperture, a tubular spacer having an internal circumferential groove adjacent to one end thereof, the ends of the arms of the holding member engaging in the groove to hold the spacer in a predetermined position relative to the threaded member, whereby a bolt or screw may be engaged with the threaded member through the spacer.

9. A fixing arrangement, substantially as described with reference to Figures 4 and 5 of the drawings.