GB2059893A - Overhead suspensions for platforms - Google Patents

Abstract

A system for suspending a working platform 5 from an overhead structure comprises beams or rails 9, 10 coupled to the platform and suspended from the overhead structure by elongate supports 11 and bogies 15. Each bogie 15 being connected to a pair of supports 11 suspended in pairs from ribs, arches or other frame members, located between adjacent bogies 15. The bogies are spaced by struts 12, and the supports and struts include length adjusters 21, 22. The platform may be advanced by a winch, supports being are dismantled at one end and assembled at the other. Alternatively the platform may be advanced by shortening struts 11 and supports 11 at the rear end with the rear bogies 15 clamped to the rails 9, 10. <IMAGE>

Description

SPECIFICATION Refurbishing overhead structures The invention relates to refurbishing large span overhead structures.

We have made and applied to patent a previous proposal in which runway beams or rails are secured in mutually spaced, generally parallel relation to ribs, arches or other members of an overhead structure, usually to span a small number thereof. Conviently those runway beams or rails are displaceable relative to the structure and in the direction of their lengths. From these runway beams or rails, a working platform is suspended, advantageously by flexible elongate means, such as cables, adjustably attached to the platform and secured to sliders or trolleys able themselves to move along the runway beams or rails.This system has proved to be highly satisfactory in practice as the runway beams need span only a few of the ribs, arches or other frame members so long as that allows extension of those runway beams or rails relative to the platforms and structure sufficiently to attach their ends via suitable couplers to the next arch, ribs or other frame member.

Rigid, strong runway beams or rails permit this to be done from a lightweight cradle run out along each extended runway beam or rail.

The main working platform can then again be moved along the runway beams or rails for work to progress, often from sub-platforms thereof at different heights and usually heightadjustable.

However, some overhead structures have such large spacings between ribs, arches or other frames members suitable for rail suspension, at least in the direction of desired platform travel, that intolerable flexing of the runway beams or rails occurs under the weight of their affixing cradles and occupants, or the runway beams or rails have to be made unduly oversize and overweight for their main purpose of supporting the working platform.

It is one object of the invention to provide a reduction of the impact of this problem.

To this end, we now propose that runway beams or rails be close coupled to the working platform and be themselves suspended at a convenient height below the overhead structure corresponding to convenient platform working height preferably by way of elongate couplers, or hangers that interconnect each of pairs of spaced positions along the rails with different ones of spaced positions on the ribs, arches or other frame members, each such latter position being vertically above the spacing between the associated positions along the runway beams or rails.

This type of arrangement greatly reduces, usually halves, the extent to which a runway beam or rail has to be cantilevered in its extension beyond an end-most one of the normal runway beam or rail support positions in repositioning the working platform. Additional advantages are obtained where, as is specifically envisaged herein the runway or rails are incorporated in the working platform as the structural integrity of the whole is then high, perhaps especially so where the runway beams or rails are fixed in the working platform structure rather than being relatively moveable.

The end-most part of a working platform having fixed rails can be extended beyond its last existing suspension position to be below the next desired support position while a ladder is extended therefrom to secure elongate couplers or hangers to that next support position in complete safety.

We have found that this is advantageous where elongate couplers or hangers are also inclined out of vertical planes through the platform so as to connect with most convenient ones of the frame members of the overhead structure. Then, the hangers or other elongate couplers of different runway beams or rails can share the same upper frame member in order to maintain the desired position of the working platform transversely of its desired direction of travel. With our prior system, the runway beams or rails constrained the overhead structure connection positions to be aligned.

Preferably, suspension means from each runway beam or rail to an elevated support position on the overhead structure comprises two said hangers that diverge from a shackle at that elevated position to spaced sliding or rolling couplings, shoes or trolleys on the runway beams or rails, and a strut extending between them. Then, each of the hangers and the struts may be length adjustable, meaning they can be utilised in traverse of the platform especially where runway beams or rail couplers can be locked.

Practical implementation of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic side elevation of a suspended working platform; Figure 2 is a diagrammatic end view or section of a working platform and suspension similar to that of Fig. 1; and Figure 3 is a similar view to Fig. 2 of a variant working platform and suspension.

In Figs. 1 and 2 of the drawings, a working platform 10 comprises a deck 5 on a rigid support frame comprising two orthogonal sets 6 and 7 of superposed parallel I-beams as bearers secured together by bolting or welding or in any other convenient way. In Fig. 2 lower edges of ends of the lower set of bearers 7 are shown relieved at 8 in order to locate neatly on lower flanges of I-section rails 9, 10. In Fig. 1, the rail 10 is shown broken away below its upper flange. It will, however, be appreciated that the rails 9, 10 may be of lesser height than the thickness of the working platform, with the lower bearers 7 then underlying the bottom flanges of the rails 9, 10.

As illustrated in Figs. 1 and 2, the rails 9 and 10 will be rigidly secured to the lower platform bearers 7 and the entire platform will have a rigidity suitable for heavy duty operations, including the mounting thereon of various machinery and/or the provision of jackable platforms to give alternative heights of working levels.

Normally, and as indicated in Fig. 3 the working platform will, in fact, have a substantial width and be provided with intermediate rails, such as that shown at 11. The break lines in Figs. 2 and 3 indicate that and working platforms hereof generally have a maximum width consistent only with convenience and avoiding of any obstacle below an overhead structure to be refurbished. In that way entire spanning frame members of a roof may be dealt with successively by the working platform as it is traversed along a structure in the direction of the rails 9, 1 0, 11 and transversely of those spanning frame members.

The deck 5 stops short of the end rails 9 and 10 and also of all intermediate rails 11 so that generally C section roiler coupler 1 5 can have their rollers 1 6 engaged under the top flanges of the rails and be moveable along the rails. If desired, such movement may be limited, but normally is not, the rails effectively being in slots in the upper deckings.

The rail couplers 1 5 are each secured to ends of two hangers 11 that diverge from the couplers to spaced overhead securement positions on arches, ribs or other frame members 20 of the overhead structure 10 to be refurbished. These hangers 11 may be rigid rods, bars or tubes, but are usually flexible cables, chains or the like, and have length adjustment devices 21 along their length so that attachment to the overhead structure can be at different height as will usually be required in order to service an arched, hipped or pitched overhead structure. Fig. 3 actually shows by dashed lines and reference numerals, an alternative height of such securement. Normally that securement will be by way of readily released and attached couplers, for example of a medially jointed claw type.

Fig. 2 shows the hangers 11 in vertical planes through assocated rails, where as Fig.

3 shows the hangers suspended from frame members intermediate the spacing between rails 9, 10 and 11.

The rail couplers 1 5 are also interconnected by struts 1 2 are parallel to the rails and also advantageously include length adjustment devices 1 2. These can contribute to suspension height adjustment though to a lesser extent than larger length adjuster 21, commensurate with still permitting the desired platform traversing shortly to be described.

First, however, it is noted that Fig. 3 shows the hangers of adjacent rails secured to common frame members of the overhead structure so that, in effect, four hangers will connect to and diverge from substantially the same overhead structure position.

The fact that ends of the working platform extend beyond verticals through the overhead suspension position 20 materially assists traversing the platform in the direction of the rails 9, 10, 11. Thus, for an advance in the direction of arrow 25, the suspension arrangement shown dashed and referenced 18 in Fig.

1 will be dismantled by personnel using ladders or powered iifts, and the entire platform will be moved in the direction of the arrow 25 and relative to the couplers 1 5, say using a winch 26 acting between the platform and one or more of the couplers 1 5 on two or more of the rails. At least as soon as the end of the platform is below the next overhead frame member 20 to be used, it will be safe for personnel to attach hangers 11 to that frame member, one of each pair of such hangers then being, or already being, attached to the end most coupler of each rail.

The other larger of each pair can also be attached to its rail coupler if then free on the rail or at minimum length of its associated strut 12 with movement of the platform continued until the desired length of the strut 1 2 is achieved. Normally, of course, the struts will have a nominal length equal to the spacing between frame members 20, but, clearly, can accomodate differences therein as well as permit of some height adjustment.

For an advance in the direction opposite to arrow 25 the suspension arrangement 19 is the one that is dismantled.

It is to be noted that the entire platform progression could be achieved simply by successively shortening the end most ones of the hangers 11 of the suspension arrangements to be dismantled so long as their associated rail couplers can be locked on the rails and/or platform, followed by contraction of the strut 1 2 thereof.

The rigidity of the working platform as a whole will normally be sufficient to obviate any substantial bending on its enxtension during traverse, but that would in fact be tolerable by the present arrangement at least in view of the length adjustable capability of the hangers 11, at least where the maximum unsupported extension is effectively one half of the spacing between the frame members 20. However, at least where the rails 9, 10, 11 are of less depth than the platform, they could be slidable relative to the platform and extended alone for securement to the next frame member 20 prior to drawing the platform itself over them to the desired position.

We also envisage that cradles may be slung from below the platform for particular work operations. Also subplatforms and associated rails may be extendable and retractable relative to the main platform at any position, usually sideways and from below into side galleries or low roofed parts of the overhead structures.

Once erected, working platforms of this invention are wholly independent of any assistance from the ground in their gradual traverse of an entire roof or bridge structure to be serviced.

Claims (11)

1. A system for suspending a working platform from a large span overhead structure, comprising runway beams or rails close coupled to the working platform, the beams or rails themselves being suspended at a convenient height below the overhead structure corresponding to convenient platform working height.

2. A system as claimed in claim 1 wherein the beams or rails are suspended by way of elongate couplers or hangers which interconnect each of pairs of spaced positions along the rails with different ones of spaced positions on the ribs, arches or other frame members of the overhead structure, each such latter portion being vertically above the spacing between the associated position along the runway beams or rails.

3. A system as claimed in claim 1 or 2 wherein the beams or rails are incorporated in the working platform.

4. A system as claimed in claim 3 wherein the beams or rails are fixed in the working platform.

5. A system as claimed in claim 4 wherein the end-most part of the working platform is extendable beyond its last-existing suspension position to below the next desired support positions.

6. A system as claimed in any one of claims 2 to 5, wherein the elongate couplers or hangers are inclined out of vertical planes through the platform so as to connect with most convenient ones of the frame members of the overhead structure.

7. A system as claimed in claim 6 wherein the hangers or couplers of different beams or rails share the same upper frame member in order to maintain the desired position of the working platform transversely of its desired direction of travel.

8. A system as claimed in any one of claims 2 to 7 wherein suspension means from each runway beam or rail to an elevated support position on the overhead structure comprises two said hangers which diverge from a shackle at the elevated position to spaced sliding or rolling couplings, shoes or trolleys on the runway beams or rails, and a strut extending between them.

9. A system as claimed in claim 8 wherein the hangers and the structure length adjustable.

10. A system as claimed in claim 9 wherein the runway beam or rail couplers can be locked.

11. A system for suspending a working platform from a large span overhead structure substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.