AU757492B2

AU757492B2 - Cable ladder assembly

Info

Publication number: AU757492B2
Application number: AU89548/98A
Authority: AU
Inventors: Andrew Crick
Original assignee: Unistrut Australia Pty Ltd
Current assignee: Unistrut Australia Pty Ltd
Priority date: 1997-10-26
Filing date: 1998-10-27
Publication date: 2003-02-20
Anticipated expiration: 2018-10-27
Also published as: AU8954898A

Description

S F Ref: 427161

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: ASSOCIATED PROVISIONAL [311 Application No(s) PP0043 Unistrut Australia Pty Limited 89 Kurrajong Avenue Mount Druitt New South Wales 2770

AUSTRALIA

Andrew Crick Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Cable Ladder Assembly oe e APPLICATION DETAILS [331 Country

AU

[321 Application Date 28 October 1997 The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5815 1 4 CABLE LADDER ASSEMBLY Field of the Invention The following invention relates to cable ladder assemblies. More particularly, though not exclusively, the invention relates to a cable ladder assembly including a number of components to be interconnected on site, which components are capable of being stacked for transportation with a density that is higher than that which is applicable for known prefabricated cable ladders.

It is known to provide cable trays and cable ladders for the purpose of suspending cables which extend substantially horizontally beneath a roof or ceiling for example. For o10 low load applications, cable trays are provided, whereas for high load applications, cable ladders are provided. A cable ladder includes a trough having side walls and a number of •go rungs extending between the side walls. The rungs are welded to or otherwise secured to the side wall in the factory or on site. The purpose of the rungs is to support the cables and provide open spaces for the passage of air which cools the cables as they conduct S0 15 electricity.

A problem with known prefabricated cable ladders is that there stacking density for 0 transportation is low and as a result transportation costs are high.

The invention also relates to an intersection of cable ladder assemblies.

o Where known cable ladders intersect, for example where they cross or form a T or 20 L connection, the side walls must be removed from the ladders in the vicinity of the intersection to allow cables supported by each ladder to enter the intersection region and pass either across the intersection or around a corner. This is a labour intensive and time o consuming practice. Also, in the vicinity of the intersection, good air flow is restricted by an intersection base plate for example.

Object of the Invention It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages and/or more generally to provide an improved cable ladder assembly.

Disclosure of the Invention There is disclosed herein a cable ladder assembly including: a pair of side wall beam members, each having a plurality of longitudinally spaced slots therein, and a plurality of rungs adapted to span between the side wall beam members, each rung including opposed ends, each of which includes at least one tab adapted to be received by a respective one of said slots.

Preferably, each tab includes an extension and a recess by which the tab is engaged with the respective slot in the side wall beam member.

[N:\LIBLL]01136:KEH 2 Alternatively, each tab is adapted to extend into a respective slot and then be welded to the respective side wall beam member.

Preferably, the slots in each side wall beam member include discrete sets of slots.

Preferably, each set of slots includes two spaced apart, parallel, co-extensive slots extending in a direction transverse to the longitudinal extent of the side wall beam member.

Preferably, each set of slots also includes a further slot extending in a direction parallel with the longitudinal extent of the beam member and situated between said parallel slots.

l0 Preferably, the sets of slots further includes a further pair of slots which each S"extend in the direction parallel to the longitudinal extent of the side wall beam members with each further slot being situated longitudinally outside of the parallel transversely extending slots.

Preferably, said further slots are located near a longitudinal edge of the side wall beam member.

Preferably, each side wall beam member takes the form of a C channel with the opening of the C facing outwardly in the assembled cable ladder.

Preferably, each rung includes a U channel which is adapted to be inverted, in use.

0 20 Preferably, each rung includes a pair of opposed side faces extending from Sopposed edges of a top face.

Preferably, each rung includes a pair of opposed lips, each lip extending outwardly from respective side faces.

Preferably, the top face includes a plurality of apertures through which air can pass.

Preferably, a tab extends from each side face.

Preferably, two of said tabs, with their extensions and recesses are provided at each end of each rung, each tab extending from an end of one of said side faces.

Alternatively, a tab can extend from the top face.

In this alternative, a pair of further tabs can be provided, each further tab extending from an end of one of said lips.

ST

[kA\LmLL] lO859specie.doc:kcb Brief Description of the Drawings Preferred forms of the present invention will now be described, by way of example only with reference to the accompanying drawings, wherein: Fig. 1 is a schematic parts-exploded perspective view of a cable ladder assembly; Fig. 2 is a schematic perspective view of an intersection of four cable ladder assemblies; Fig. 3 is a schematic partial end elevational view of a cable ladder assembly; Fig. 4 is a schematic partial end elevational view of another cable ladder assembly; Fig. 5 is a schematic partial end elevational view of a number of further cable ••ladder assemblies stacked one upon another in a transportation configuration.

":Fig. 6 is a schematic partial end elevational view of another cable ladder •assembly in an in-use configuration; and "Fig. 7 is a schematic partial end elevational view of a plurality of stacked cable ladder assemblies, with each cable ladder assembly being shown in an out-folded, transportation configuration.

Detailed Description of the Preferred Embodiments .i In Fig. 1 of the accompanying drawings there is schematically depicted some of the parts of a cable ladder assembly. In Fig. 1 two alternative rungs 11 and 11' are shown 20 for ease of illustration.

Each assembly includes a pair of opposed, longitudinally extending, parallel, cooooo extensive side wall beam members 10. These members can be galvanised steel, extruded aluminium or other strong material.

[R:\LIBLL 1859spevie.doc:keh Each wall beam member takes the form of a C facing outwardly from one another when assembled.

Each side wall beam member 10 includes a set of slots 16. Each set of slots 16 includes a pair of parallel spaced apart slots 12 which extend in a direction transverse to the longitudinal extent of the side wall beam member. Positioned between each slot 12 is a longitudinally extending slot 19. Positioned along side a lower edge 18 of each side wall beam member 10 is a further pair of slots 17. These slots 17 are shorter than slots 12 and 19.

Rung 11 is typically fabricated from roll formed steel, extruded aluminium or other strong material. Each rung 11 includes a pair of side faces 20 at the bottom edges of which there extends one of a pair of lips 21. Each side face 20 at both respective ends •o*.includes a tab 13 having a downward extension 14 defining a recess 15. Tabs 13 are adapted to pass through slots 12 and then slide downwardly such that a portion of the side *owall beam member 10 is received within the recess The rung 11 also includes a top face 12 having an array of apertures 23 therethrough.

An alternative rung 11' is shown in Fig. 1. This alternative rung includes a central tab 24 extending from each end of its top face 22. The rung also includes a pair of *smaller tabs 25, each extending from opposed ends of each lip 21. These tabs 25 are adapted to be received by the smaller slots 17 whereas the central tab 24 is adapted to be received by central slot 19.

In order to secure rung 11' to the side wall beam member 10, appropriate welding 27 (Fig. 4) can be applied to the tab 24. Once assembled, the rungs 11 (or 11') and a pair of side wall beam members 10 form an assembly 26.

As shown in Fig. 2, four cable ladder assemblies 26 are shown extending from an intersection 30. Intersection 30 includes four intermediate side wall members 31, opposed ends of each of which are attached to the respective ends of the side wall beam members by means of a connecting plate 32. Each plate 32 includes 1350 bend.

A mesh tray 34 is suspended in the intersection 30 by interconnection with each of said intermediate side wall members 31. The mesh tray 34 typically includes crossing steel strands which are welded together and preferably galvanised. A number of connecting plates 33 are provided to secure the mesh tray to the intermediate members.

Each connecting plate 33 includes a loop surrounding a strand of the mesh in tray 34 and a tab screwed, riveted or otherwise affixed to the inside surface of the respective intermediate side wall member 31.

Optionally, a curved corner piece 35 can be provided with opposed ends being received by the side wall beam members 10 of the respective intersecting cable ladder assemblies 26.

[N:\LIBLL]01136:KEH In use, electrical cables are supported by the rungs 11, 11' between the respective side wall beam members 10. The curved corner piece 35 serves to protect the cable as it passes around the corner within the inner section The intersection 30 might alternatively be in the form of a T or an L. As yet a further alternative, the respective cable ladder assemblies 26 need not extend at right angles from one another. As can be appreciated, air is allowed to pass around the supported cables both throughout the extent of each ladder assembly and at the intersection An alternative cable ladder assembly is shown in Fig. 5. In this assembly, side walls 50 taper upwardly and outwardly from rungs 11". The rungs 11" can be welded at 27 to the inside bottom edge of the side wall 50. As is depicted, a number of assembled ••cable ladders can be transported with one stacked upon another in a high density configuration.

0•In Figs. 6 and 7 there is depicted an alternative cable ladder assembly. Each assembly includes a deck member 40 at each opposed end of which there is provided a protrusion 48, beneath which there depends a hinge member 41. A side wall 42 is provided at its bottom edge with a corresponding hinge member 43 which surrounds the hinge member 41. Extending inwardly from the side wall member 42 is a lug 44 having a catch 47 in its bottom surface. The lug 44 further includes an internally threaded recess 49 within which a screw 45 can be threadingly received.

The transportation configuration of the assembly is shown in Fig. 7 with several outfolded assemblies stacked one upon another. In order to erect the side walls, they are simply folded upwardly such that the catch 47 snap engages over the protrusion 48. The bottom portion of the side wall 42 abuts against a face 46 which extends between the protrusion 48 and hinge member 41. To prevent the side wall 42 from folding down, the screw 45 is threadingly inserted into the recess 49 to prevent resilient deformation of the lug 44.

It should be appreciated that modifications and alterations obvious to those skilled in the art are not to be considered as beyond the scope of the present invention. For example, the particular arrangement of slots within set 26 can be altered without departing from the scope of the invention.

[N:\LIBLL]01136:KEH

Claims

1. A cable ladder assembly including: a pair of side wall beam members, each having a plurality of longitudinally spaced slots therein, and a plurality of rungs adapted to span between the side wall beam members, each rung including opposed ends, each of which includes at least one tab adapted to be received by a respective one of said slots.

2. The assembly of claim 1, wherein each tab includes an extension and a recess by which the tab is engaged with the respective slot in the side wall beam member.

3. The assembly of claim 1, wherein each tab is adapted to extend into a respective slot and then be welded to the respective side wall beam member.

4. The assembly of any one of the preceding claims, wherein the slots in each side wall beam member include discrete sets of slots.

5. The assembly of claim 4, wherein each set of slots includes two spaced apart, parallel, co-extensive slots extending in a direction transverse to the longitudinal extent of the side wall beam member.

6. The assembly of claim 4, wherein each set of slots also includes a further slot extending in a direction parallel with the longitudinal extent of the beam member and situated between said parallel slots. 20

7. The assembly of claim 6, including a further pair of slots which each extend in the direction parallel to the longitudinal extent of the side wall beam members with each further slot being situated longitudinally outside of the parallel transversely extending slots.

8. The assembly of claim 7, wherein said further slots are located near a longitudinal edge of the side wall beam member.

9. The assembly of any one of the preceding claims, wherein each side wall beam member takes the form of a C channel with the opening of the C facing outwardly in the assembled cable ladder.

The assembly of any one of the preceding claims, wherein each rung includes a U channel which is adapted to be inverted, in use.

11. The assembly of any one of the preceding claims, wherein each rung includes a pair of opposed side faces extending from opposed edges of a top face.

12. The assembly of claim 11, wherein each rung includes a pair of opposed lips, each lip extending outwardly from respective side faces.

13. The assembly of claim 11, wherein the top face includes a plurality of apertures through which air can pass.

14. The assembly of claim 12, wherein a tab extends from each side face.

The assembly of claim 14, wherein two of said tabs, with their extensions and recesses are provided at each end of each rung, each tab extending from an end of one of said side faces. [N:\LIBLL]01136:KEH

16. The assembly of claim 14, wherein a tab extends from the top face.

17. The assembly of claim 16, wherein a pair of further tabs is provided, each further tab extending from an end of one of said lips.

18. The assembly of claim 1, wherein the side wall beam members can taper slightly outwardly and upwardly in an in-use orientation of the cable ladder.

19. A cable ladder assembly, substantially as hereinbefore described with reference to the accompanying drawings. Dated 16 December, 2002 Unistrut Australia Pty Limited Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON .e *e [R:\LIBLL]10859specie.doc:keh