AU609866B2 - Cable ladder - Google Patents

Description

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6 9 ~SQf: '340 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION This document contains the amendments made under Section 49 and is correct for printing.

(ORIGINAL)

00 00 0o 0 0 0 0 o0 O0 ooo Application Number: FOR OFFICE USE: Class Int. Class PI4375 0 0 00 0 0 00 0 0 00 0 00 0 0 0 o0 0 0 00 0 0 Lodged: 16 September 1987 Accepted: Published: Priority: Related Art: oooo Name and Address of Applicant: o 00 0 0 0 000 0 Actual Inventor: Address for Service: Siemens Limited 544 Church Street Richmond Victoria 3121

AUSTRALIA

Zvonko Nadinic Spruson Ferguson, Patent Attorneys, Level 33 St Martins Tower, 31 Market Street, Sydney, New South Wales, 2000, Australia Complete Specification for the invention entitled: Cable Ladder The following statement is a full description of this invention, including the best method of performing it known to me/us 5815/2 i ALLOWED 5805/2 4i I. III I1111 I

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ABSTRACT

The present invention discloses a cable ladder to which electric cables are secured. The ladder is transportable in a knock down configuration and can be assembled on site by unskilled labour. The ladder is formed from parallel rungs interconnecting two longitudinal members by means of a two part securing arrangement.

-4- I 1 I* Tu: 'inB luvij1VusbbiUN Ui J Av''TaI'lA S&F REF: 28340 -2- The present invention relates to the laying of electric cables, and more particularly but not exclusively, to a ladder-like structure along which such cables run and to which they are secured.

In many cases large currents run through the cables creating strong magnetic forces. Accordingly, it has been necessary to provide the ladder-like assemblies, for securing to a structural member such as a wall or frame in order to maintain safety. In the past, such cable ladders have been of a general configuration consisting of two longitudinal beams and cross rungs as in a normal step ladder. These ladders have been fully welded and thenhot dip galvanised. The fully assembled unit is then transported to the site for installation. Due to the size of these cable ladders, the galvanising operation has been quite awkward, and both this operation and the transportation of the ladder has been costly. A more versatile cable ladder has been constructed which allowed for the rungs to °1 o° pivot so that the ladder collapsed flat. However, although this reduced the volume of the object to be transported, the erection of the pivotable I 0o ladder required skilled labour.

o It is an object of the present invention to overcome or substantially ameliorate the abovementioned disadvantages of the prior art by the provision of a cable ladder transportable in a knocked down configuration.

Obviously, the components of the cable ladder can be individually hot dip 0oO::o galvanised to further reduce costs.

o According to the present invention there is disclosed a cable ladder for supporting electric cables, said cable ladder comprising a pair of longitudinal members and a plurality of rungs, said rungs being of substantially equal length and connectable between said longitudinal 60.0. members in parallel arrangement at spaced apart locations along said BI longitudinal members each said rung being individually connectable to each one of said longitudinal members by a three part securing arrangement comprising a first part located at each said spaced apart location, a second part located at each end of each said rung, said first and second parts being fabricated from the material of either said longitudinal members or said rungs, and being mutually interengaged on assembly of said ladder; and a third part able to interlock said first and second parts to maintain engagement therebetween.

e4 i i 1 I i -3- The present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a perspective view of an assembled cable ladder according on the rungs; Fig. 2 shows the cable ladder of Fig. 1 in the preassembled state; Fig. 3 shows an exploded view of the arrangement for securing the rungs to the longitudinal member of the cable ladder of Fig. 1; Fig. 4 shows the assembled arrangement of Fig. 3; Fig. 5 is a view similar to that of Fig. 3 but illustrating an alternative arrangement; and Fig. 6 shows the assembled arrangement of Fig. 0 In Fig. 1 there is depicted a cable ladder 10 with cables 11 supported by the rungs 12 of the ladder 10. The rungs 12 stretch between 0 longitudinal members 13, at predeterm.ned intervals. The cable ladder 0 0: is attached to a wall or structure (not shown) and the cables 11 are secured to the rungs 12 in known fashion.

As best seen in Figs. 2 to 6, the cable ladder 10 is made in a I preassembled form, and there are several methods of ssembling the ladder The components of the ladder 10, i.e. the rungs 12, the longitudi:al members 13, and securing pins 14 are treated, for example hot dip galvanised, in the form that they are presented in Fig. 2, and are thus easily handled during manufacture. In addition the individual components o2 are easily boxed and transported. Obviously, this reduces the cost and expertise required in manufacturing and transporting of the ladder U' I I p k

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In Fig.3 there is depicted a first embodiment of the arrangement for securing the rungs 12 to the longitudinal members 13. In this embodiment, a flange 15 extends at right angles to the main portion 22 of the longitudinal member 13 and a hollowed projection 16 is formed on the flange The end of a rung 12 has a mating aperture 23 therein to fit over the projection 16. A longitudinally slotted pin 14 fits through a slot 18 provided in the main portion 22 of the longitudinal member 13 and through the hollow of the projection 16 to secure the rung 12 to the flange 15 of 0o0 0 the longitudinal member 13.

The assembled configuration is shown in Fig.4. It can be seen that the particular pin 14 used in this embodiment has a tapered arrow-shaped 0 Oo head 26 with a longitudinal slot 24 therein. The tapered head 26 allows the two halves 20 and 21 to be forced together as they enter the projection 0000 16 and expand when the head 26 exits, so that the barbs on the head 26 lock 000 the rung 12 In place.

00O A further embodiment is shown in Figs.5 and 6 wherein the projection me. 0 and aperture arrangement are reversed on the rung 12 and longitudinal member 13 respectively.

It should be appreciated that the provision of an unassembled ladder gives rise to cost savings since the bulk or volume to be transported is reduced. There is also a cost saving on site since the cable ladder 10 can be assembled without the need for skilled labour, such as welders.

I The foregoing describes only two embodiments of the present invention, and modifications obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention.

For example, some rungs 12 can be provided with the arrangement of Figs 3 and 4 and the remaining rungs can be provided with the arrangement of Figs 5 and 6. Also any equivalent means for securing the rungs 12 to KSP/264o -4- I i. .the longitudinal members 13 could be substituted. Also the longitudinal members 22 are preferably longitudinally corrugated as at 25 for extra strength for any given gauge of metal.

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Claims (12)

1. A cable ladder for supporting electric cables, said cable ladder comprising a pair of longitudinal members and a plurality of rungs, said rungs being of substantially equal length and connectable between said longitudinal members in parallel arrangement at spaced apart locations along said longitudinal members each said rung being individually connectable to each one of said longitudinal members by a three part securing arrangement comprising a first part located at each said spaced apart location, a second part located at each end of each said rung, said first and second parts being fabricated from the material of either said longitudinal members or said rungs, and being mutually interengageable on °o °o assembly of said ladder; and a third part able to interlock said first and second parts to maintain engagement therebetween. 4

2. A cable ladder as claimed in claim 1 wherein the parts located at the rung ends are substantially identical, and the parts located at said spaced apart locations are substantially identical.

3. A cable ladder as claimed in claim 1 or 2 wherein one of said first and second parts is an aperture, and the other of said first and second parts is a protrusion shaped to mate with said aperture, said protrusion having an opening therein, and said third part comprises a locking pin insertable through said opening after mating of said protrusion and aperture to retain said protrusion so inserted.

4. A cable ladder as claimed in claim 3 wherein said pin is 1 longitudinally slotted at its leading end.

A cable ladder as claimed in claim 4 wherein said leading end of said pin is shaped like an arrow head having barbs which retain said pin inserted in said protrusion opening.

6. A cable ladder as claimed in claim 5 wherein the other end of said pin is provided with a barbed head.

7. A cable ladder as claimed in any one of claims 3 to 6 wherein said first part comprises said protrusion and said second part comprises said aperture.

8. A cable ladder as claimed in any one of claims 3 to 6 wherein said first part comprises said aperture and said second part comprises said protrusion.

9. A cable ladder as claimed in any one of the preceding claims wherein each said longitudinal member is substantially L-shaped in 7 transverse cross section being formed from a stem and a flange, said first parts of said securing arrangements being located on said flange.

A cable ladder as claimed in claim 9 wherein said stem is longitudinally corrugated.

11. A cable ladder as claimed in any one of the preceding claims wherein said rungs are of C or U-shaped cross-section.

12. A cable ladder for supporting electric cables, said cable ladder being substantially as described with reference to Figs. 1 to 4 or Fig. 1 and Figs. 5 and 6 of the accompanying drawings. DATED this THIRTEENTH day of NOVEMBER 1990 Siemens Limited 00 On 0 0 0 0 0 0 00 00 0 00oo0 Patent Attorneys for the Applicant o oo SPRUSON FERGUSON 0o a 0 0 o 0 0 0 00 0 0 0000 0 0 00 0 oooo 0 0 00 0 0 0 0 0 00 00 a a C 0 0000 i