GB2143885A

GB2143885A - Fire-ladder with extendable ladder sections

Info

Publication number: GB2143885A
Application number: GB08418271A
Authority: GB
Inventors: Erwin Maass
Original assignee: Iveco Magirus AG
Current assignee: Iveco Magirus AG
Priority date: 1983-07-23
Filing date: 1984-07-18
Publication date: 1985-02-20
Also published as: GB8418271D0; JPS6040491A; DE3326644A1; FR2549523B1; GB2143885B; FR2549523A1; DE3326644C2; JPH0438878B2

Abstract

The ladder rails are fitted with lower 8 and upper 9 supports held together by angle braces 10. Upper supports 9 and consist of a rectangular tube 26 with a downwards-pointing flange, to which angle braces 10 are fastened. The lower ends of the angle braces are welded to the lower supports 8, to which the ladder rungs are also welded. Supports 8 are made from flat T-, L- and/or Z-section pieces. Corrugations 13 and 16, and the hollow sections of the supports, can accommodate remote- control cables 33. The individual profiled pieces and the rungs and angle braces can be fastened together by external robot welding. Sets of ladders having 3, 4, 5 or 6 sections of equal or differing length can, with the greatest ease, be placed in the same apparatus and welded. <IMAGE>

Description

SPECIFICATION Fire-ladder with extendable ladder sections The invention is concerned with a multi-section fire-ladder having extendable ladder sections, which can be extended against an outer ladder section, rigidly fixed to an erection frame, the ladder rails of which have a lower support and an upper support which are strongly joined together by means of angle braces.

Fire-ladders with extendable ladder sections, of a kind already known, whose ladder rails have a lower support and an upper support rigidly held together by angle braces are, where the lower support and upper support are concerned, profiled in such a way as to have a high degree of resistance to twisting and bending. In order to achieve this, rails with complicated cross-sections are employed, containing multiple corrugations and multiple bends. The rails are further reinforced by means of added sections such as cross braces and four-sided tubing, as is known, for example, from DE-PS 28 44 439. The various sets of ladders are consequently expensive to produce. Moreover, the individual sections of ladders have differing cross-sections, so that series production is difficult to arrange. The welds have to be made partly by welding internally (spot and roller spot welding).Robot welding for the purpose of reducing production costs is virtually impossible.

The purpose of the invention is to create a fire-ladder with extendable ladder sections, the ladder rails of which, whilst having an adequate resistance to twisting and bending, have a simplified cross-section, so as to ena ble series manufacture with robot welding to be undertaken.

The problem on which the invention is based is solved by means of the features specified in the distinctive part of claim 1, involving the use of a single T-section piece.

That is to say the lower support is to be formed by a T-section bent at 90 and having unequal legs, the base of which has at its free end a rolled-in corrugation facing upwards, the upper longer leg of which has a rolled-in corrugation facing inwards, and the shorter lower leg of which has a 90 outwards-facing bend, in which the portion of the proffile lying between the two rolled-in corrugations serves, partly at least, as a track or slideway for a lower support, with the same cross-section, of a section of ladder lying above it. Alternatively the solution may be by means of two profiled pieces (L-section and Z-section).That is to say the lower support is formed by an L-section turned through 90 , the legs of which have at their free ends rolled-in corrugations directed towards each other, and by the fact that a or L-profiled section is welded to the exterior angle edge, so that a lower outwards-pointing flange is formed, in which the portion of the profile lying between the two rolled-in corrugations serves partly at least as a track or slideway for a lower support, with the same cross-section, of a ladder lying above it. Both alternative ways of carrying out the invention can include an extra Z- or L-section as claimed in claim 6, in order to give the lower support a four-sided profile, in which the angle braces penetrate into the interior of the four-sided tube section. The last-mentioned way of carrying out the invention affords added resistance to twisting and bending.

The rungs of the fire-ladder are positioned on the lower side of the T-section base abutting the T-roots and welded there, (first variation in accordance with the invention), or positioned and welded on the lower side of the L-section abutting the root of the flange (second variation in accordance with the invention).

The arrangements covered by the invention have the advantage that for the lower support, a standard rail cross-section is achieved, which lends itself to the use of welding techniques (the same lower support cross-section on each individual ladder section). The individual parts which form any section of ladder (rungs, profiled parts of the lower support, angle braces and upper support) can be rigidly fastened together more easily by external welding. This enables robot welding equipment to be employed, making possible cost-saving series production. Through the invention, there is absolutely no need for additional reinforcing material to be welded in, so that 30 to 40% fewer welds are required.

In the case of the design variant using a rectangular tube cross-section for the lower support, the inner surfaces require no conservation, as all the parts can be welded so as to be air-tight. The upper and lower rolled-in corrugations as well as the rectangular tube profile of the lower support are recommended for use as closed channels for carrying (remote control) cables, for instance, when using a rescue cage or a lift on the fire-ladder. This means that state of the art cable conduits are not required.

A particular useful further development of the invention calls for the upper ends of adjacent angle braces to be arranged slanting towards one another, and to be welded to the upper support. It is recommended that the upper support should consist of an off-centre rectangular tube having a downwards-pointing flange. The upper ends of the angle braces are welded to the outside of the lower flange.

Production of this, too, can be simplified by robot welding. The rectangular tube of the upper support can also be used as a cable conduit. As with the lower support profile, the cross-section used for the upper support differs in size between the various ladder sections, but has the same configuration.

The lower ends of the angle braces are designed to be welded (by external welding) to those points on the lower support where the ends of the rungs are also welded. This creates junctions in the lower support, in which the transmission of force of the angle braces and the rungs is directly maintained.

The inner U-shaped sections as well as the outer surffaces of the lower support serve as a track or slideway for the lower support of a ladder section lying over it, to which are fastened at the appropriate points sliders for vertical and sideways movement.

An additional L-section, of substantially the same pattern as the lower support profile, can if necessary be provided at appropriate points in the plane of the rungs, for reinforcing purposes.

Finally, according to a further and specially beneficial characteristic of the invention, the angle braces of at least two neighbouring ladder sections are arranged so as to have the same angle of slant compared with the corresponding lower and upper supports. This has the important advantage that the individual ladder sections of various ladder sets can be placed in the same apparatus, and welded.

The invention is hereafter described in detail on the basis of embodiment examples and with reference to the drawing. The figures show: Figure 1 in diagrammatic front elevation, the right half of a fire-ladder with six ladder sections, Figure 2 a cross-section of the lower support of a ladder section in another embodiment, and Figures 3 to 6 details of a fire-ladder section showing, in perspective, the assembly sequence of a lower support, in accordance with Figure 2.

In Figure 1 are shown the ladder rails, with rungs 20, on one side only of a fire-ladder 1 and its six sections 2 to 7. The individual ladder sections 2 to 7 fit into one another telescopically in the region of lower support 8.

The lower supports 8 carry, on the outside, sliders 29 and 31, with fastening rods 28 and 32 respectively. Slider 29 serves for vertical movement and slider 31 for horizontal movement in the direction of the axis of the rungs.

The individual laddcr sections 2 to 7 carry rungs 20, the ends of which are welded to two lower supports 8. Each lower support is welded to the lower ends of vertically-positioned and slanting angle braces 10, the upper ends of which are fastened rigidly by external welding to the underside of the corresponding upper support 9.

Each upper support 9 of ladder sections 2 to 7 has essentially the same cross-section, consisting of an off-centre rectangular tube 26, having a downwards-pointing flange 27, the outside of which serves for fastening the angle braces 10. Both the upper and lower side of rectangular tube 26 are used as a roll or slideway for a lift 30.

Like the upper supports 9, the individual lower supports 8 of the sections of ladder are of differing dimensions, but their cross-sections are identical. Lower support 8 as shown in Figure 1 is made up of a T-section with unequal legs 11, with an additional Z- or L- section 1 9 welded to it, and accordingly consists of two parts.

The T-section has a base 12, which is provided at its free end with a rolled-in corrugation 13, formed upwards. The upper longer leg 1 4 of the T-section carries a rolled-in corrugation 1 6 facing inwards, while the shorter leg 1 5 of T-section 11 has a 90 bend 1 7 pointing outwards. Between the upper inwards-facing rolled-in corrugation 1 6 and the lower 90 bend 17, the Z- or L-section is welded on the outside, forming a closed rectangular hollow section for the lower support, which lends added rigidity.

The rungs 20 of any section of ladder are positioned on the underside of base 12, abutting the root of the 90 bend 17, and are welded there. The lower ends of angle braces 10 extend through corresponding openings in the tops of the Z- or L-sections 1 9 into the interior of the rectangular hollow section of the lower support, to meet the upper side of the 90 bend 1 7, and are similarly welded there.

All the welds can be produced by external welding, so that robot welding with series production of ladder sections is possible.

The interior of rolled-in corrugations 1 3 and 16, as well as the four-sided hollow section of the lower support or the upper support can be used to accommodate remote control cables 33. A remote control cable 34 is also placed in the interior angle of the lower support of the (top) ladder section 7.

In Figure 2, a cross-section of another lower support 8 is depicted, and consists, in particular, of three separate profiled pieces, being an L-section 1 8 with mutually facing rolled-in corrugations 21 and 22 at its ends, a lower Zsection 24 to form an outwards-pointing lower flange 23 plus another additional Z- or Lsection 19, patterned after the embodiment of Figure 1, so as to constitute a rectangular cross-section. All the aforementioned individual profiles are easily prefabricated from flat sheets by bending and rolling-in, and welded to rungs 20 and angle braces 10, in the manner shown in Figures 3, 4 and 5.

First of all, as shown in Figure 3, the individual rungs 20 are welded at intervals to lower Z-section 24, and likewise the angle braces 10 to the outside of U-section 1 8.

Then, the welded parts in Figures 3 and 4 are assembled as shown in Figure 2, and the rungs 20 welded to the underside of L-section I 8. ollowing that, the Z-section 1 9 with its top openings 25 for the angle braces 10 (see Figure 5) is joined to the outside and welded top and bottom to the other two parts 1 8 and 24. The lower ends of the angle braces 10 are thus situated at the points where the rungs 20 are fastened, creating a junction able to ensure a good transfer of force between diagonals and rungs. It is thereffore clear that a lower support 8 can be produced easily from original flat sheets, which are suitably bent and/or rolled to produce corrugated stiffening, this being done exclusively by joining together, by external welding, the profiled parts, the rungs 20 and the angle braces 10, a process requiring the making of only a few welds, yet producing a highly stable support, resistant to twisting and bending, and light in weight.

In Figure 6, which illustrates in a partially drawn section, similar to Figure 2, a further alternative, an L-section 24' is used in place of the Z-section 24 (Figure 2). By this means, the recess provided on the L-section 1 8 (Fig- ure 2) at the junction with the Z-section 24 (Figure 2) is no longer needed, especially as, instead of the latter, a simple L-section 24 only is provided.

Claims

1. Fire-ladder with ladder sections, which can be extended against an outer ladder section, rigidly fixed to an erection frame, the ladder rails of which have a lower support and an upper support which are strongly joined together by means of angle braces, in which the lower support is to be formed by a Tsection bent at 90 and having unequal legs, the base of which has at its free end a rolledin corrugation facing upwards, the upper longer leg of which has a rolled-in corrugation facing inwards, and the shorter lower leg of which has a 90 outwards-facing bend, in which the portion of the profile lying between the two rolled-in corrugations serves, partly at least, as a track or slideway for a lower support, with the same cross-section, of a section of ladder lying above it.

2. Fire-ladder as claimed in claim 1, in which the rungs are positioned on the lower side of the T-sectioned base, abutting the Troot, and welded there.

3. Fire-ladder with ladder sections which can be extended against an outer ladder section, rigidly fastened to an erection frame, the ladder rails of which have a lower support and an upper support, which are solidly joined together by means of angle braces, in which the lower support is formed by an L-section turned through 90 , the legs of which have at their free ends rolled-in corrugations directed towards each other, and by the fact that a Zor L-profiled section is welded to the exterior angle edge, so that a lower outwards-pointing flange is formed, in which the portion of the profile lying between the two rolled-in corrugations serves partly at least as a track or slideway for a lower support, with the same cross-section, of a section of ladder lying above it.

4. Fire-ladder as claimed in claim 3, in which the rungs are positioned on the underside of the L-section abutting the root of the flange, and welded there.

5. Fire-ladder as claimed in claims 1 to 4, in which the angle braces fixed to the upper support are positioned on the outside of the leg containing the upper rolled-in corrugations and abutting the upper side of the lower outwards-facing bend or flange, next to a rung, and there welded by external welding.

6. Fire-ladder as claimed in claims 1 to 5, in which the lower support has an additional Z- or L-section, welded on the outside, between the upper rolled-in corrugations and the lower outer 90 bend or flange, so as to form a rectangular cross-section, with the angle braces reaching into the inside of the rectangular tube profile.

7. Fire-ladder as claimed in claim 6, in which L-sections are provided, running parallel to the lower support, in the plane of the rungs, these being substantially of the same pattern as the lower support cross-section.

8. Fire-ladder as claimed in claims 1 to 7, in which the upper ends of neighbouring angle braces are arranged so as to be slanting towards each other and are welded to the upper support, which consists of an off-centre four-sided tube having a downwards-pointing flange, the outside of which serves as a base for welding the angle brace.

9. Fire-ladder as claimed in claims 1 to 8, in which the rolled-in corrugations and/or the interior of the rectangular tube of the upper support serve to house cables.

1 0. Fire-ladder as claimed in claims 1 to 9, in which the top and the bottom of the rectangular tube of the upper support serve as a track or slideway for a lift.

11. Fire-ladder as claimed in claims 1 to 10, in which the angle braces of at least two neighbouring ladder sections are positioned with the same angle of slant compared with the associated lower supports or upper supports.

1 2. Fire-ladder substantially as described herein with reference to the accompanying drawings.