AU775243B2 - Cable ladder assembly - Google Patents

Description

S&FRef: 501813

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant Unistrut Australia Pty Limited 89 Kurrajong Avenue Mount Druitt NSW 2770 Australia Actual Inventor(s): Address for Service: Roderick McDonald Spruson Ferguson St Martins Tower 31 Market Street Sydney NSW 2000 Cable Ladder Assembly Invention Title: ASSOCIATED PROVISIONAL APPLICATION DETAILS [33] Country [31] Applic. No(s) AU PP9415 [32] Application Date 24 Mar 1999 The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5815c 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 ~10 low load applications, cable trays are provided, whereas for high load applications, cable :ladders are provided. A cable ladder includes a trough having side rails and a number of rungs extending between the side rails. Generally, the rungs are welded to or otherwise secured to the side rails in the factory or on site. When connecting the rails and rungs by use of bolts or screws the electrical conductivity of the assembly is not optimized and the S- 15 sharp edges can cause potential damage to the adjacent cables. Once the rungs and the side rails have been secured they then need to be galvanized. 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 electricity.

A problem with known prefabricated cable ladders is that there stacking density for 20 transportation is low and as a result transportation costs are high. Further, possible corrosion may occur between the welded rung and side rail due to interface corrosion for example. Furthermore, the use of bolts and screws for securing components adds considerable time and expense to the construction of a cable ladder assembly.

It is an 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 firstly disclosed herein a cable ladder having: a pair of side rails which are generally parallel and transversely spaced; IR:\L1 BTTj02329.doc:mzh 2 a plurality of rungs extending between the rails at spaced locations along the rails, each rung having opposite end portions attaching the rung to the side rails; and connecting means securing each end portion to its associated rail, each connecting means including a flange integral with or attached to the rail so as to extend therefrom in a direction substantially parallel to the rungs and a section of each end portion and its associated flange being plastically deformed securing each associated end portion and flange together.

There is secondly disclosed herein a cable ladder having: a pair of side rails which are generally parallel and transversely spaced; i 10 a plurality of rungs extending between the rails at spaced locations along the rails, each rung having opposite end portions attaching the rung to the side rails; and connecting means securing each end portion to its associated rail, each connecting means including a flange integral with or attached to the rail so as to extend therefrom in a direction substantially parallel to the rungs; and wherein said associated end portion and flange are connected by a plastically deforming rivet.

Preferably, the rivet is a self piercing rivet.

eoo* :Preferably, the connection means are in the form of a bracket having a flange and two feet attachable to the side rails.

Alternatively, said connection means are in the form of a flange formed by punching a slot for the receipt of said rung in said side rails.

Preferably, each side rail includes discrete sets of brackets/slots.

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

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

I R:\LI B1"02329.doc: mzh Preferably, the set of brackets/slots further include a further pair of brackets/slots which each extend in the direction parallel to the longitudinal extent of the side rail with each further bracket/slot being situated longitudinally outside of the parallel transversely extending brackets/slots.

Preferably, said further brackets/slots are located near a longitudinal edge of the side rail.

Preferably, each side rail takes the form of a C channel with the opening of the C facing either inwardly or outwardly in the assembled cable ladder.

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

o 10 Preferably, each rung includes a pair of opposed side faces extending from opposed edges ofa 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 flange extends from each side face.

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

.i Alternatively, a flange can extend from the top face.

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

In an alternative assembled cable ladder, the side rail can taper slightly outwardly and upwardly in the in-use orientation of the cable ladder.

Preferably, the side rail is extruded PVC, aluminium or steel.

Preferably, the top face of the rung can be located above or below the flange.

Preferably, the rung can extend between or through the side rails.

Hlowever, it should be appreciated that other materials and fabrication techniques can be adopted for each component.

IR:ALIBTT0j2329.doc:mzh 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. I is a schematic parts-exploded perspective view of a cable ladder assembly; Fig. 2 is a magnified perspective view of the cable ladder assembly connection; Fig. 3 is a schematic parts-exploded perspective view of a second embodiment of a cable ladder assembly; Fig. 4 is a magnified perspective view of the cable ladder assembly connection of Fig. 3; 10 Fig. 5 is a magnified perspective view ofa cabble ladder assembly connection according to the invention; Fig. 6 is a magnified perspective view of another embodiment of a cable ladder assembly connection; Fig. 7 is a schematic cut away section of the cable ladder assembly connection as 15 shown in Fig. 4; and o• Fig. 8 is a schematic cut away section of the cabble ladder assembly connection as shown in Fig. Detailed Description of the Preferred Embodiments In Fig. 1 of the accompanying drawings there is schematically depicted some of the parts of a cable ladder assembly 1. In Fig. 1 two rungs 2, 3 are shown, one attached to the connection means 4 and one separated.

The assembly 1 includes a pair (only one shown) of opposed, longitudinally extending, parallel, co-extensive side rails 5. These rails 5 can be galvanized steel, extruded aluminium or other strong material.

Each rail 5 takes the form ofa C facing either inwardly or outwardly from one another when assembled.

[R:\LI BTTj02329.doc:mzh Each side rail 5 includes a set of brackets 6. Each set of brackets 6 includes a flange 7 which extends in a direction transverse to the longitudinal extent of the side rail Rungs 2, 3 are also typically fabricated from roll formed steel, extruded aluminium or other strong material. Each rung 2, 3 includes a pair of side faces 8. These side faces 8 may include a pair of lips (not shown).

The rungs 2, 3 also include a top face 9 having an array of apertures 10 therethrough.

In order to secure connection means 4 to the side rail 5 riveting or plastically deformation can be applied to the bracket 6. Figures 1 and 2 illustrate a first preferred method of connecting rungs 2, 3 to connection means 4 and in turn to side rail 5. The connection means 4 in the form of bracket 6 includes first and second feet 12, 13 for riveting I 1 the bracket 6 to the side rail 5. The bracket 6 also includes a flange 7 which facilitates :the correct positioning of rung 2, 3 and securing of the top face 9 of rungs 2, 3 to the bracket 6 by riveting 11.

In Figures 3, 4 and 5, the connection means 4 is in the form of flange 14 formed by punching a slot 15 in the side rail 5. During assembly, each rung 2, 3 is inserted through said slot 15 and the flange 14 provides a locating and securing surface to rivet 11 (Figure 4) or plastically deform 16 (Figure 5) the top face 9 of the rungs 2, 3 to the flange 14. Once assembled, the rungs 2, 3 and a pair of side rails 5 (only one shown) form an assembly 1.

Figure 6 illustrates another method of connecting rungs 20 to connection means S 20 and in turn to side rail 50. Connection means 40 in the form of a bracket 60 may or may not include a flange (such as in Figure 2) which can assist the correct positioning of rung 20 and securing of the top face 90 of rung 20 to the bracket 60. Bracket 60 includes first and second feet 120, 130 which include at least one rivet 110 for securing the bracket 60 to the side rail 50. In this particular embodiment four rivets 110 are shown, these rivets 110 being plastically deformed as shown in Figure 7. To assist speedy construction, the rung 20 is prefabricated with the bracket 60 already welded 80 to the rung 20, in effect replacing flange 7. As mentioned above, the combination of rung 20 and bracket 60 is then riveted to s e 1"1 Figure 7 illustrates in more detail the plastically deforming self piercing rivet 11 securing, for example, flange 7,14 to rung 3 of Figures. 1 to 4. Alternatively, Figure 8 IR:ALI BT702329.doc: mzh illustrates in more detail the securing, for example, of flange 14 to rung 3 by plastic deformation 16 as shown in Figure Optionally, a curved corner piece (not shown) can be provided with opposed ends being received by the side rails 5 of the respective intersecting cable ladder assemblies 1.

In use, electrical cables are supported by the rungs 2, 3 between the respective side rails 5. The curved corner piece (not shown) serves to protect the cable as it passes around the corner within an inner section.

An intersection might alternatively be in the form ofa T or an L. As yet a further alternative, the respective cable ladder assemblies 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 an intersection.

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.

ooo° I R:\LI BTT102329.doc:mzh

Claims (24)

1. A cable ladder having: a pair of side rails which are generally parallel and transversely spaced; a plurality of rungs extending between the rails at spaced locations along the rails, each rung having opposite end portions attaching the rung to the side rails; and connecting means securing each end portion to its associated rail, each connecting means including a flange integral with or attached to the rail so as to extend therefrom in a direction substantially parallel to the rungs and a section of each end portion and its associated flange being plastically deformed securing each associated end !0 portion and flange together.

2. The ladder according to claim 1, wherein said associated end portion and flange are connected by a plastically deforming rivet.

3. The ladder according to claim 2, wherein the rivet is a self piercing rivet.

4. The ladder according to any one of claims 1 to 3, wherein the connecting means is in the form of a bracket having a flange and two feet attachable to the side rails.

The ladder according to any one of claims 1 to 3, wherein said connecting means is in the form of a flange formed by punching a slot for the receipt of said rung in said side rails.

6. The ladder according to claim 4 or claim 5, wherein each side rail includes discrete sets of brackets/slots. i

7. The ladder according to claim 6, wherein each set of brackets/slots includes two spaced apart, parallel, co-extensive brackets/slots extending in a diiectioi transverse to the longitudinal extent of the side rail. oool [R:\LIBTT]02329.doc:mzh:KEH 8

8. The ladder according to claim 6 or claim 7, wherein each set of brackets/slots also includes a further bracket/slot extending in a direction parallel with the longitudinal extent of the rail and situated between said brackets/slots.

9. The ladder according to claim 8, wherein the set of brackets/slots further include a further pair of brackets/slots which each extend in the direction parallel to the longitudinal extent of the side rail with each further bracket/slot being situated longitudinally outside of the parallel transversely extending brackets/slots.

The ladder according to any one of claims 5 to 9, wherein said brackets/slots are located near a longitudinal edge of the side rails.

11. The ladder according to any one of the preceding claims, wherein each side rail takes the form of a C channel with the opening of the C facing either inwardly or outwardly in the assembled cable ladder.

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

13. The ladder according to any one of the preceding claims, wherein each rung includes a pair of opposed side faces extending from opposed edges of a top face.

14. The ladder according to claim 13, wherein each rung includes a pair of opposed lips, each lip extending outwardly from respective side faces.

The ladder according to claim 13 or claim 14, wherein the top face includes a plurality of apertures through which air can pass.

16. The ladder according to claim 14, wherein a flange extends from each end portion of said rung.

17. The ladder according to claim 16, wherein each flange extends from an end of one of said side faces.

18. The ladder according to claim 16, wherein each flange can extend from the top face. [R:\LIBTT02329.doc:mzh:KEH

19. The ladder according to claim 18, wherein a pair of further flanges can be provided, each further flange extending from an end of one of said lips.

The ladder according to claim 12, wherein the side rails can taper slightly outwardly and upwardly in the in-use orientation of the cable ladder.

21. The ladder according to any one of the preceding claims, wherein the side rail is extruded PVC, aluminium or steel.

22. The ladder according to claim 13, wherein the top face of the rung can be located above or below the flange.

23. The ladder according to any one of the preceding claims, wherein the rung can extend between or through the side rails.

24. A cable ladder substantially as herein described with reference to any one of the embodiments of the invention shown in the accompanying drawings. Dated 28 May, 2004 Unistrut Australia Pty. Limited Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [R:\LIBTTj02329.doc:mzh:KEH