GB2357543A

GB2357543A - Structural members with provision for attachment to a safety device

Info

Publication number: GB2357543A
Application number: GB9930628A
Authority: GB
Inventors: Christopher Patrick Noe Cronin
Original assignee: Total Fabrications Ltd
Current assignee: Total Fabrications Ltd
Priority date: 1999-12-24
Filing date: 1999-12-24
Publication date: 2001-06-27
Anticipated expiration: 2019-12-24
Also published as: GB9930628D0; GB2357543B

Abstract

A structure includes a number of longitudinally extending elongate elements (10, 11, 12, 13) having transverse elements (14, 15, 16, 17, 18, 19, 20, 21) extending between, where the longitudinal elements include, along their length, a formation for engagement by an attachment member (Figures 3 and 4), such as a safety device. Preferably the formation is a T shaped slot (32, Figure 2) and at least one of the transverse elements, located at a corner of the structure, also includes such a formation.

Description

2357543 Title: Structural Members Despbpfion of Invention This invention

relates to structural members.

More particularly the invention relates to: structural members which are intended for the construction of permanent or temporary structures for use in what may broadly be regarded as the entertainment industry. By way of example but not limitation, such structures may be used in association with a stage for the presentation of a musical/theatrical event, for the support of a roof over a stage, for carrying lighting, sound, scenery or other production equipment, or indeed anything that may be required. In many cases such structures are temporary if an event is taking place for a short period of time, but such a structure may well be permanently installed at a location. A further exwnple of a structure which may incorporate structural members in accordance with the invention is an exhibition stand, but in its broadest aspect structural members in accordance with the invention may be used wherever a requirement arises therefor.

The basic element from which structures may be assembled is a "truss", and more particularly a structural member in accordance with the invention may be such a truss. A truss characteristically comprises a number of elongate elements secured in spaced generally parallel relationship to one another by a number of transversely extending elements therebetween. The transversely extending elements are arranged to ensure that the truss is adequately strong and rigid for the loads it is intended 'to bear: typically some transversely extending elements extend perpendicularly to the elongate elements while others extend diagonally therebetween. In transverse cross-section, a truss may be square or rectangular or possibly of other polygonal shapes such as 2 triangular, with principal elongate elements at the corners thereof For special purposes, some trusses are able to be folded flat to occupy a minimal space for storage or transportation and erected to their polygonal cross-sectional shape when required to be used. There are many known configurations of truss, and the invention is applicable generally throughout the range of such configurations.

A structure may be created by joining a plurality of trusses together in the required configuration using suitable releasable fastenings. A structure may incorporate parts at a substantial height above a floor or ground level, and riggers assembling the structure have to work at such heights. After the structure has been completed, further work will be necessary to mount other items such as lighting equipment on the structure. Whilst theoretically a rigger should use separate access equipment for safe working at a height in practice the structure itself may be climbed upon and this brings obvious dangers in case a rigger should fall from the structure. With this in view, a rigger may attach himself to a safety line which is clipped to a truss in the region in which he is working, but this inhibits freedom of movement and if a fall occurs may impose loads on the structure which could damage the structure, possibly even causing collapse thereof. Add-on fall-arrest systems have been proposed, but these may interfere with the structure imposing undue loads thereon, and generally are inconvenient.

It is broadly the object of the present invention to address the abovedescribed problem of assisting safety of persons working at a height on a structure as above described.

According to one aspect of the above invention, therefore, we provide a structural member comprising a number of elongate elements disposed in spaced generally parallel relationship to one another with transversely extending elements therebetween, an element extending longitudinally of the 3 member being provided with a lengthwise extending formation for holding, for movement therealong, a member adapted for connection to a safety element.

Preferably the structural member is of polygonal shape in cross-section with said elongate elements at the corners thereof. If the structural member is a truss of the Idnd above referred to which is able to be folded flat, such polygonal shape applies when it is erected from the folded condition. Preferably it is at least one of said elongate elements which has a or a respective said lengthwise extending formation. Further preferably all of said elongate elements are of the same cross-sectional shape as one another, and thus each has a said formation.

Said formation may comprise an undercut slot extending lengthwise of said element, said slot preferably being T-shaped so as to receive, for sliding movement lengthwise of the formation, a member having a correspondingly T-shaped portion. Such an element may be placed in the slot lengthwise at the end of the element and then held captive therein by application thereto of a suitable fastener, or when the structural member is secured to another structural member.

Conveniently each of said elongate elements is an extrusion of an appropriate aluminium alloy. However, other materials may be suitable and it is contemplated that possibly a plastics material, possibly fibrereinforced, may be usable. Apart from a portion thereof having said formation, the or each elongate element may be generally box-shaped., According to a further aspect of the invention, we provide a structure comprising at least one structural member in accordance with the first aspect of the invention as above set forth--- The invention yet further provides such a structure having one or more members engaged with said formation(s) thereof, and a safety device such as a safety line connected to at least one of said members.

4 The invention will now be described by way of example with reference to the accompanying drawings, of which:- Figure 1 is a perspective view of part of a structural member in accordance with the invention; Figure 2 is a transverse cross-section through one of the elongate elements utilised in the structural member; Figures 3 and 4 are respectively an end elevation and side elevation of a member which may be engaged with the elongate element.

Referring firstly to Figure 1 of the drawings, the structural member or truss, part of which is illustrated comprises four elongate elements 10, 11, 12, 13 disposed in spaced generally parallel relationship to one another. In transverse cross-section of the structural member, the elements are at the corners of a square but it will be appreciated that alternative structural members may have the elongate elements at the corners of another polygon, e.g. a rectangle or triangle. Other longitudinally extending elements may be provided if required.

The elements 10 to 13 are maintained in their relative position by a number of transversely extending elements therebetween. Four elements 14, 15, 16, 17 extend perpendicularly to the elements 10 to 13 along the sides of the square, adjacent the free ends of the elements 10 to 13. A further four such transverse elements 18, 19, 20, 21 extend between the elements 10 to 13 at a spacing therealong from the end thereof, and further such transverse elements are provided at intervals as required along the length of the structural member. There are further intermediate perpendicular transverse elements 22, 23 between the elements 10, 11, 12 and 13 respectively, mid-way between the transverse elements in square configuration. Additionally there are diagonal bracing elements 24, 25, 26, 27 extending between the elements 10 to 13.

All the above described elements may be extrusions of an aluminium alloy, secured to one another by welding. However, the invention does not exclude the use of other materials, e.g. steel or possibly even plastics materials.

The cross-sectional shape of the elements 10 to 23 is shown enlarged in Figure 2. Its envelope is square, comprising a box-section portion 30 and a portion 31 in which is provided an undercut T-shaped slot 32. On its outside, the element has longitudinally extending ribs 33 which render it easier to grip and thus facilitate handling of the structural member and erection of a structure using such members.

The slot 32 is adapted to receive a member as shown in Figures 3 and 4, the member being generally T-shaped in end elevation with a head 35 to be received in the slot 32 for sliding movement therealong and a body 36 which protrudes from the slot. The body 36 is provided with apertures 37 for the connection of a safety device, e.g. a safety line.

To make the member of Figures 3 and 4 more easily slidable along the slot 32 in the elongate element, there are guide ribs 38 within the slot 32 and friction-reducing coatings may, if required, be utilised on appropriate parts of the elongate element and member engaged therewith.

A member as shown in Figures 3 and 4 may be engaged with an element as shown in Figure 2 by sliding the member into the open end of the element, and thereafter it may be retained therein by the use of appropriate fastening means or be held captive when the structural member is secured to another structural member in use. A structural member may be supplied with a respective slidable member in each of the elongate elements forming the structural member, or in only one or some thereof. Whilst it is convenient for the structural member to be made of elongate elements which are of the same cross-sectional shape as one another such that each may be engaged by a slider member, this need not be the case: only one or some of the elongate elements may be thus shaped. In the broadest aspect of the invention, it would be 6 possible for an additional elongate element to be provided in the structural member, having a cross-sectional shape specifically for engagement by a slider member for connection to a safety element.

In the present specification "comprise" means 'Includes or consists of' and "comprisinj means "including or consisting of'.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed flinction, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof

Claims

7 CLAIMS

1. A structural member comprising a number of elongate elements disposed in spaced generally parallel relationship to one another with transversely extending elements therebetween, an element extending longitudinally of the member being provided with a lengthwise extending formation for holding, for movement therealong, a member adapted for connection to a safety element.

2. A structural member according to Claim 1 which is of polygonal shape in cross-section with said elongate elements at the corners thereof.

3. A structural member according to Claim 2 wherein it is at least one of said corner elongate elements which has a or a respective said lengthwise extending formation.

4. A structural member according to any one of the preceding claims wherein all said elongate elements are of the same cross-sectional shape as one another.

5. A structural member according to any one of the preceding claims wherein said forrnation comprises an undercut slot in said longitudinally extending element.

6. A structural member according to Claim 5 wherein said undercut slot is T-shaped in cross-section.

8 7. A structural member according to Claim 6 wherein said member comprises a T-shaped part received in said slot for sliding movement therealong.

8. A structural member according to any one of the preceding claims wherein each said elongate element comprises an extrusion of an aluminium alloy.

9. A structural member according to Claim 8 wherein apart from said fonnation each elongate element is of box section.

10. A structure comprising at least one structural member according to any one of Claims 1 to 9.

11. A structure according to Claim 10 comprising one or more members engaged with said formation(s) thereof, and a safety device connected to at least one of said members.

12. A structural member, or structure incorporating same, substantially as hereinbefore described with reference to the accompanying drawings.

13. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.