WO1994029547A1

WO1994029547A1 - An arrangement in connection with a maintenance bridge or the like

Info

Publication number: WO1994029547A1
Application number: PCT/FI1994/000242
Authority: WO
Inventors: Harri Ovaska; Markku PYLVÄNÄINEN; Mikko Helander
Original assignee: Kasten-Høvik Oy
Priority date: 1993-06-09
Filing date: 1994-06-07
Publication date: 1994-12-22
Also published as: FI932643A; AU6846994A; FI932643A0

Abstract

The invention relates to an arrangement in connection with a maintenance bridge or the like, comprising a bearing structure formed of cantilever beams (4) and cross-beams (5) disposed thereon, and grating elements (6) or the like fitted on said bearing structure, adapted to form a planar walking or working surface. To provide a simple and rigid construction, the cantilever beams (4) and cross-beams (5) are formed in a manner known per se from sheet material by roller shaping and welding of parts into a closed casing structure, and the cantilever beams (4) and cross-beams (5) are adapted to be secured to one another by means of connection pieces (7) matching with the shape of the outer surface of the sides of the beams (4, 5).

Description

An arrangement in connection with a maintenance bridge or the like

The present invention relates to an arrange- ment in connection with a maintenance bridge or the like, comprising a bearing structure formed of canti¬ lever beams and cross-beams disposed thereon, and grating elements or the like fitted on said bearing structure, adapted to form a planar walking or working surface.

Various maintenance bridges or catwalks are very common in different fields of industry. An example of the technical fields in which maintenance bridges and catwalks are much in use is the process industry. Maintenance bridges and catwalks are used to a great extent in connection with large-sized machinery, such as papermaking machines and steam boilers, the neces¬ sary maintenance, repair and control operations being performed from upon said maintenance bridges or cat- walks. The same structures are also employed in connection with such machinery as running boards bet¬ ween maintenance points and similar of the different parts of the machinery.

In most cases, maintenance bridges and cat- walks are constructed individually on the site, i.e. such bridges are constructed to directly fit in the existing structures on the site. The drawback with such solutions is their complexity, the difficulty of manu¬ facture, since all structures must be designed and manufactured separately in accordance with the condi¬ tions in each case. A ^• ..rther drawback is the high consumption of material and the consequent heavy weight which again increases the costs.

To eliminate the above drawbacks, solutions have been proposed that employ prefabricated sections. Examples of such solutions include those disclosed in DE Offenlegungsschrift 2 916 826, GB patent specifi¬ cations 1 352 696 and 1 588 723 and U.S. Patent 4 984 654. The drawback of these solutions, however, is their complexity and, as a result, an expensive struc¬ ture that is difficult to manufacture.

It is an object of the present invention to provide an arrangement wherewith the drawbacks of the prior art can be eliminated. This has been achieved with the arrangement of the invention, which is charac¬ terized in that the cantilever beams and cross-beams are formed in a manner known per se from sheet material by roller shaping and welding of parts into a closed casing structure, and that the cantilever beams and cross-beams are adapted to be secured to one another by means of connection pieces matching with the shape of the outer surface of the sides of the beams.

The advantage of the invention is above all the fact that it enables a rigid and load-withstanding structure to be achieved. The casing structure of the cantilever beams and cross-beams has a very good bend¬ ing strength in the direction of the main load, and the casing structure is also of advantage in view of twist¬ ing and torsional instability when compared with open profiles. The cantilever beams and cross-beams of the arrangement of the invention are very advantageous to manufacture. For example, the manufacturing can be very advantageously automated. The parts of the structure are also fairly light, which is expedient in view of installation. Furthermore, the arrangement of the invention is very flexible and can thus be adapted advantageously according to need in various situations. A further benefit is that the arrangement can be very advantageously formed from module-size parts, which keeps the manufacturing costs of the structure low. Still another advantage of the invention is that it is suitable for use in connection with both new plants and arrangements made in connection with the repair and renovation of old, existing plants. For instance, by means of the invention, that part or those parts of the old maintenance bridges of existing equipment in which modifications due to changes in the structure of the equipment are to be made can be advantageously replaced, and so on. In the following the invention will be set forth in greater detail by means of a preferred embodi¬ ment presented in the accompanying drawing, wherein

Figure 1 shows an arrangement of the invention in a schematic general view, and Figures 2-5 show details of the arrangement of

Figure 1 viewed from different directions.

Figure 1 shows a general view of an arrange¬ ment of the invention. The arrangement comprises an actual platform 1 and accessory parts secured to the platform, for example steps 2, railings 3, etc. The arrangement of Figure 1 can be fixed at any suitable location, such as the wall of a paper aking machine, and thus maintenance, running, repair and other similar work required in the papermaking machine can be per- formed upon standing on the actual platform.

Figures 2-5 show various details of the arran¬ gement of Figure 1. It is clearly seen from Figures 2-5 that the arrangement of the invention comprises a bear¬ ing structure formed of cantilever beams 4 and cross- beams 5 disposed thereon substantially at a right angle, for instance. Furthermore, grating elements 6 or the like are fitted on the bearing structure provided by the beams 4, 5, said grating elements being adapted to form a planar walking or working surface. In accordance with the essential concept of the invention, the cantilever beams 4 and cross-beams 5 are formed from sheet material by roller shaping and welding of parts into a casing structure. On account of the structure of the beams 4, 5, their manufacture can be very advantageously automated. The cantilever beams 4 and cross-beams 5 are adapted to be secured to one another by means of connection pieces 7 matching with the shape of the sides of the beams 4, 5. The connection pieces 7 can also be adapted to serve as means employed for fixing the railings 3 or the like. The connection pieces 7 can be formed from sheet mater¬ ial by bending, for instance. However, the connection pieces 7 can naturally also be manufactured by using other techniques. Examples of other possible methods for manufacturing the connection pieces are casting, welding from parts and even employing roller shaping and cutting techniques.

On account of the closed casing structure of the beams 4, 5, they have very good strength and cor- rosion-resistance properties while being light, and this is of advantage in the installation step. The installation can be performed part by part, but the manner of joining the parts also allows pre-assembly into larger installation blocks. The cantilever beams 4 can be fixed for example to the wall of a papermaking machine by means of a flange 8 and bolts. Such a detail is shown in Figure 2. The bearing structure is built up from canti¬ lever beams 4 and cross-beams 5, as set forth previ- ously. The bearing structure formed by the cantilever beams 4 and cross-beams 5 is clearly seen in Figure 5. Figure 5 also clearly shows the grating elements 6 or the like, which are fitted on the bearing structure made up by the beams 4, 5 and is adapted to form a planar walking and working surface. The cantilever beams 4 and cross-beams 5 are secured to one another by means of connection pieces 7. This is clearly seen in Figures 3 and 5. The connection piece 7 can, for example, be welded onto the end of beam 4 or 5, allowing the next beam to be secured to the connection piece by means of a bolted joint, for instance, as shown in Figure 3. The shape of the con¬ nection piece 7 corresponds to the shape of the beam 4, 5, so that the connection piece 7 abuts the side of the beam 4, 5.

In accordance with the essential concept of the invention, the connection pieces 7 can also be used as fixing means for railings 3 or the like. This is clearly shown in Figures 2, 3, 4 and 5. Since the shape of the connection pieces 7 corresponds to the shape of the beams 4, 5, for example the fixing points for rail¬ ings 3 can be advantageously provided at any point in the beam 4, 5, with no modifications being needed in the actual connection piece 7. Naturally, any accessory structures, such as steps 2, edge railings and so on can be attached to the arrangement. The accessory structures can be fixed by any known means, but it is obvious that if necessary, also connection pieces 7 can be employed for fixing the steps 2, for example.

The cantilever beams 4 and cross-beams 5 may also preferably be formed as module-sized parts, which is of advantage in view of manufacture and storage. In such an implementation, the concept is that the entire maintenance bridge can be constructed of module-sized beams 4, 5. The modular dimension can adv. .tageously be selected in accordance with the target jf use, for example specific dimensions of a papermaking machine, and thus it is possible to advantageously dimension the entire maintenance bridge to correspond to the dimen- sions of the papermaking machine. Such a solution is technically very advantageous and essentially dimin¬ ishes the manufacturing costs of the maintenance bridge in comparison with the prior art. With a few correctly selected basic modular dimensions for the beams, most of the practical implementations can be covered, which will make the final result advantageous.

The embodiment set forth above is in no way intended to restrict the invention, but the invention may be varied with full freedom within the purview of the claims. Thus it is obvious that the arrangement of the invention or its details need not necessarily be exactly as shown in the figures, but other solutions are possible as well. It is obvious, for example, that the beams and connection pieces need not necessarily have exactly the shape shown in the figures, but other shapes are also possible. Even though the invention has been described in the foregoing in the context of a papermaking machine, it is obvious that the invention is in no way limited to a papermaking machine but can be implemented in connection with any equipment or structure. The grating elements can also be manufac¬ tured by any methods known per se. Nor is the arran¬ gement of the invention restricted to any specific material, but the manufacturing material can be freely selected according to the circumstances in each case.

Claims

Claims:

1. An arrangement in connection with a main¬ tenance bridge or the like, comprising a bearing struc- ture formed of cantilever beams (4) and cross-beams (5) disposed thereon, and grating elements (6) or the like fitted on said bearing structure, adapted to form a planar walking or working surface, c h a r a c t e r ¬ i z e d in that the cantilever beams (4) and cross- beams (5) are formed in a manner known per se from sheet material by roller shaping and welding of parts into a closed casing structure, and that the cantilever beams (4) and cross-beams (5) are adapted to be secured to one another by means of connection pieces (7) matching with the shape of the outer surface of the sides of the beams (4, 5).

2. An arrangement as claimed in claim 1, c h a r a c t e r i z e d in that the connection pieces (7) are also adapted to serve as means employed for fixing the railings (3) or the like.

3. An arrangement as claimed in claim 1 or claim 2, c h a r a c t e r i z e d in that the cantilever beams (4) and cross-beams (5) are formed as module-sized parts.