AU770750B2

AU770750B2 - Trunking base section with pre-formed fixing holes, and method of manufacturing it

Info

Publication number: AU770750B2
Application number: AU58326/99A
Authority: AU
Inventors: Yvon Buard; Pascal Tabuteau
Original assignee: Legrand SA; Legrand SNC
Current assignee: Legrand SA; Legrand SNC
Priority date: 1998-11-06
Filing date: 1999-11-05
Publication date: 2004-03-04
Anticipated expiration: 2019-11-05
Also published as: AU5832699A; DE69934651T2; EP0999627A1; EP0999627B1; AR021076A1; HUP9904062A3; PL336444A1; PL193814B1; BR9907373A; TR199902745A2; DE69934651D1; FR2785731A1; TR199902745A3; HU9904062D0; HU223210B1; ATE350792T1; HUP9904062A2; FR2785731B1; RU2233520C2; ZA996730B

Description

r/UU/U I I 2i5/y1 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: 4

S

Invention Title: TRUNKING BASE SECTION WITH PRE-FORMED FIXING HOLES, AND METHOD OF MANUFACTURING IT The following statement is a full description of this invention, including the best method of performing it known to us

V.

1 Trunking base section with pre-formed fixing holes, and method of manufacturing it The present invention is generally concerned with trunking of the type used for example to support, house and protect various kinds of equipment and in particular various kinds of electrical equipment, and to support, house and protect conductors or other connections to such equipment.

The trunking has a base section designed to be 10 attached to a wall and having an open cross section and a o cover which is attached to the base section, for example clipped to it, to close the assembly.

The base section of such trunking, referred to for simplicity as trunking base sections hereinafter, essentially comprises a back which is placed against the wall and by which the trunking is fixed to the wall.

It can also have a lateral flange of greater or lesser height along one or both longitudinal edges.

The back of a trunking base section of the above kind is usually fixed directly to the wall.

example, the trunking base section is preformed with at least two fixing holes in the back which are naturally separated in the longitudinal direction to make them suitable for such fixing.

In practice a plurality of longitudinally spaced fixing holes are provided in this way to make it easier for the installer to deal with local fixing conditions on site.

This feature therefore has the advantage, from the installer's point of view, of great flexibility in use; it also has the advantage of enabling the trunking base section to be fixed quickly.

However, it has the drawback of compromising the insulation of the back at the location of unused fixing holes, which means that in some applications trunking base sections with preformed fixing holes in the back cannot be used, in particular when the trunking must house single-insulated electrical conductors.

These applications usually employ trunking base sections with a solid back and the installer has to make the necessary fixing holes himself, on site.

This inevitably complicates fixing a trunking base section of this kind with a solid back.

To avoid the use of fixing holes, fixing a trunking base section by means of various accessories has previously been proposed.

For example, in the trunking described in US patent 2,921,607, U-shaped accessories must first be fitted to the wall and the trunking base section to be fixed to the wall then interengaged with them.

However, for a trunking base section of this kind to be installed correctly, the accessories must be accurately aligned with each other, which is not always easy.

Also, being visible externally, they degrade the aesthetics of the system.

A general object of the present invention is an arrangement which mitigates the above drawbacks.

Any discussion of documents, devices, acts or knowledge in this specification is included to explain the context of the invention. It should not be taken as an admission that any of the material formed part of the prior art base or the common general knowledge in the relevant art in Australia on or before the priority date of the claims herein.

t Comprises/comprising and grammatical variations thereof when used in this specification are to be taken to specify the presence of stated features, 25 integers, steps or components or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

The present invention consists in a trunking base section including a back which can be applied to a wall of any kind and which has at least two longitudinally spaced fixing holes each of which is blanked off by a plug, each plug being severed from the surrounding hole and retained in place therein; it further consists in a method of manufacturing a trunking base section of the above kind.

Briefly, the trunking base section of the invention, which has performed fixing holes in its back, is advantageously shipped with the fixing holes blanked off.

All the installer has to do on site is to free the *oooo *go **ooo *oo *go• *o*oo fixing holes he wishes to use, by removing the plug from those fixing holes, which can in practice be done very easily using any ordinary tool, for example a screwdriver.

Unused fixing holes are then advantageously still blanked off by a plug.

From the insulation point of view, it is just as if the trunking base section had a solid back.

In a preferred method of manufacturing a trunking 1 0 base section of the above kind in which the back has fixing holes blanked off by a plug, the trunking base section is extruded in the usual way and, after said extrusion, the trunking base section undergoes a punching operation which comprises two successive phases for each 15 fixing hole required, namely a first phase during which a first punch impinges on the back in a first direction, depressing it to at least part of its thickness, and a second phase during which a second punch impinges in a second direction opposite to the first one on the previously depressed portion of the back, pushing it back into the fixing hole from which it came.

Using the above method, the plug blanking off each fixing hole in the back originates from the back itself, being formed directly by the previously punched portion thereof.

Although it is put into practice after an extrusion process, the above manufacturing method is advantageously simple and economical to implement.

Also, when the plug blanking off a fixing hole is removed, the fixing hole advantageously has a particularly clean outline and in particular is free of burrs that could injure the installer or damage the electrical conductors.

The features and advantages of the invention will emerge from the following description given by way of example and with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a partial perspective view of a trunking base section in accordance with the invention, Figure 2 is a partial view of it to a larger scale and in longitudinal section taken along the line II-II in Figure 1, Figures 3A, 3B are partial views in longitudinal section derived from that of Figure 2 and showing two 10 successive phases of the punching operation which forms and blanks off a fixing hole in the back of the trunking base section, and .Figure 4 is a partial view in longitudinal section, also analogous to that of Figure 2, and showing the 15 subsequent removal of the plug blanking off a fixing S" hole.

As shown in the figures, and in a manner that is well known in the art, a trunking base section 10 in accordance with the invention has a back 11 which can be placed against a wall of any kind, not shown.

In the embodiment shown by way of example, the trunking base section 10 has, in addition to the back 11, and giving it a generally U-shaped cross section, two lateral flanges 12 substantially perpendicular to the back 11, of the same height, and having along their free edge rims 13 extending towards each other and forming at their end a groove 14 for clipping on a cover, not shown.

In the embodiment shown, the back 11 has two Tshaped cross section longitudinal ribs 16 projecting from its inside surface 15 for clipping on an accessory of any kind and/or equipment of any kind, also not shown, for example.

Being well known in the art, the corresponding features are not described in more detail here and are not to be regarded as limiting the invention in any way.

In a manner that is well known in the art, the back 11 of the trunking base section 10 of the invention has at least two longitudinally spaced fixing holes 17.

As is the case in the embodiment shown, the back 11 preferably has a plurality of longitudinally spaced fixing holes 17 aligned in one or more rows.

In the embodiment shown, there is only one row of fixing holes 17 and it is in the middle area of the back 11, between the ribs 16.

10 However, it goes without saying that other rows of fixing holes 17 can also be provided, for example on respective opposites sides of the ribs 16, between them and the lateral flanges 12.

0 The fixing holes 17 in the same row are preferably 15 at a regular pitch.

As shown, they preferably have a circular contour.

According to the invention, each of the fixing holes 17 in the back 11 of the trunking base section is blanked off by a plug 18 that can be removed.

In the embodiment shown, the plug 18 in each fixing hole 17 is flush with the inside surface 15 of the back 11, as seen more clearly in the case of one of them in Figure 2.

In this embodiment, the plug 18 is likewise flush with the outside surface 19 of the back 11.

The following method is preferably used to obtain a trunking base section whose back 11 has preformed fixing holes 17 blanked off by plugs 18 in this manner.

The trunking base section 10 is initially manufactured by extrusion in the usual way.

After such extrusion, for example immediately after it, the trunking base section 10 undergoes a punching operation which comprises two successive phases for each fixing hole 17 to be formed, namely a first phase (see Figure 3A) in which a first punch 20A impinges on the back 11 in a first direction, as symbolised by the arrow A in Figure 3A, depressing the back to at least part of its thickness E, and a second phase (see Figure 3B) in which a second punch 20B impinges in a second direction, opposite to the first one, on the previously depressed part 18' of the part 11, pushing it back into the fixing hole 17 from which it was formed, as symbolized by the arrow B in Figure 3B.

*The depressed portion 18' of the back 11 is 0 preferably braced by the second punch 20B as it is :-..:depressed during the first phase of the punching .'".operation.

As shown here, the first punch 20A preferably depresses the back 11 to only a fraction of its thickness 15 E, which fraction, as shown here, is greater than half the thickness E, for example.

As shown here, the back 11 is preferably braced during the first phase of the punching operation by a die 22 in which there is a hole 23 whose diameter D2 is less than the diameter D1 of the first punch As a result the portion 18' of the back 11 depressed by the first punch 20A has two successive sections in the direction away from the first punch namely a larger diameter section 24, whose diameter is equal to the diameter D1 of the first punch 20A, and a lesser diameter section 25, whose diameter is equal to the diameter D2 of the hole 23 in the die 22.

The larger diameter section 24 thus constitutes a kind of guard of height e through which the depressed portion 18' of the back 11 is advantageously initially contiguous therewith.

As shown here, during the second phase of the punching operation the second punch 20B preferably operates through the hole 23 in the die 22 used in the first phase.

In other words, the nominal diameter of the second punch 20B is equal to that of the hole 23 in the die 22.

Be this as it may, during this second phase of the punching operation, the depressed.portion 18' of the back 11 is detached from it and the second punch integrates it to its full thickness in the back 11, so that it forms the required plug 18.

Experience shows that the plug 18 blanking off a fixing hole 17 in this way is retained sufficiently 10 strongly in the fixing hole 17 to remain in place therein *during subsequent transportation and/or manipulation of 0 the trunking base section 10, despite impacts which the trunking base section 10 inevitably experiences.

Experience also shows that if the material from which the trunking base section 10 is made is a thermoplastics material, the inherent elasticity of the material causes the smaller diameter section 25 that the plug 18 normally has because of the process by which it is formed to fill the small space between it and the corresponding part of the wall of the fixing hole 17, which retains the plug 18 more strongly in the fixing hole 17.

This is why the corresponding theoretical void is shown only diagrammatically in dashed outline in Figure 3B.

Likewise, it is shown more or less filled in, in thicker outline, in Figure 2.

In the embodiment shown, during the first phase of the punching operation the first punch 20A operates from the inside towards the outside relative to the back 11 and during the second phase the second punch 20B operates from the outside towards the inside.

However, it goes without saying that the opposite arrangement could equally well be used.

Be this as it may, to fix the trunking base section in accordance with the invention all the installer has to do is to remove the plug 18 previously blanking off each of the fixing holes 17 he intends to use to fix the trunking, as symbolized for one of them by the arrow C in Figure 4.

Its removal can be facilitated, if required, by using any ordinary tool, for example a screwdriver, not shown.

Be this as it may,' it is very easy to remove.

10 Of course, the present invention is not limited to the embodiment and use described and shown, but encompasses any variant execution thereof.

O.

Claims

1. A trunking base section including a back which can be applied to any kind of wall and which has at least two longitudinally spaced fixing holes, each of which is blanked off by a plug, each plug being severed from the surrounding hole and retained in place therein.

2. A trunking base section according to claim 1, wherein the plug for each fixing hole is flush with the inside surface of the back.

3. A trunking base section according to claim 1 or claim 2, wherein the plug for each fixing hole is flush with the outside surface of the back.

4. A trunking base section according to any one of claims 1 to 3, wherein its back has a plurality of longitudinally spaced fixing holes arranged in one or more rows. A trunking base section according to any one of claims 1 to 4, wherein the plug has a first section having a diameter larger than that of the rest of the plug.

6. A trunking base section according to claim 5 wherein the larger diameter section is shorter than the rest of the plug. S 7. A trunking base section according to any one of claims 5 or 6, wherein the trunking base section and the plug are made of a plastics material whereby the inherent elasticity of the material causes the smaller diameter section of the plug 20 to be retained more strongly in the corresponding hole.

8. A method of manufacturing a trunking base section according to any one of claims 1 to 7, wherein the trunking base section is extruded and, after said extrusion, the trunking base section undergoes a punching operation which includes two successive phases for each fixing hole required, namely a first phase during which a first punch impinges on the back in a first direction, depressing it to at least part of its thickness, and a second phase during which a second punch impinges in a second direction opposite to the first direction on the previously depressed portion of the back, pushing it back into the fixing hole from which it came.

9. A method according to claim 8, wherein the depressed portion of the back is braced by the second punch as it is depressed during the first phase of the punching operation. A method according to claim 8 or claim 9, wherein the first punch depresses the back to only a fraction of its thickness.

11. A method according to any one of claims 8 to 10, wherein the back is braced during the first phase of the punching operation by a die in which there is a hole whose diameter is less than the diameter of the first punch.

12. A method according to claim 11, wherein the second punch operates during the second phase of the punching operation through the hole in the die 20 used in the first phase. 0: 00*

13. A method according to any one of claims 8 to 12, wherein the first punch operates from the inside towards the outside in the first phase of the punching operation and the second punch operates from the outside towards the inside in the second phase. S.oe* o oo% 25 14. A method according to any one of claims 8 to 13, wherein the plug is severed from the portion of the trunking base section defining a hole during the 0 0 second phase. 11 A trunking base section substantially as hereinbefore described with reference to the accompanying drawing.

16. A method of manufacturing a trunking base section substantially as hereinbefore described with reference to the accompanying drawings. DATED this 15th day of December 2003 LEGRAND AND LEGRAND SNC WATERMARK PATENT TRADE MARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA RLT/MAS/AXO 0 o 0