GB2305485A

GB2305485A - Flange system for board edge, e.g. for ducting

Info

Publication number: GB2305485A
Application number: GB9618826A
Authority: GB
Inventors: Joseph Paul Vincenti
Original assignee: KOOLDUCT Ltd; Pal International Srl
Current assignee: KOOLDUCT Ltd; Pal International Srl
Priority date: 1995-09-20
Filing date: 1996-09-10
Publication date: 1997-04-09
Anticipated expiration: 2016-09-10
Also published as: GB9618826D0; GB2305485B; GB9519190D0

Abstract

The system comprises two elongate members of L-shaped cross-section one comprising two webs 1, 2 only, the other having at further, parallel shorter web 5 to one web 4 to provide an insertion channel 6. The insertion channel 6 receives a free edge of the web 2 in frictional engagement, e.g. as shown by ribs on the webs 2 and 5. Preferably the width of webs 2 and 4 is substantially equal to the thickness of the board, and either or both the webs 1, 3 are adapted for frictional engagement and/or deformation of the board, e.g. by at least one longitudinal rib 7, or tangs. The members may be of aluminium or plastics (for thermal insulation, e.g. when used to assemble an air conditioning conduit).

Description

Flange System The present invention relate to the provision of a flange or edging piece at an edge of a board or panel (the term board will be used hereafter). It has particular, but not exclusive application, to boards of rigid or semi-rigid material capable of undergoing at least a small amount of compressive deformation.

A board having these qualities has recently been produced for use in forming thermally insulating ducts such as are employed for heating, ventilation and air conditioning. It consists of a rigid foamed plastics material, for example a closed cell expanded phenolic foam, although other open or closed cell expanded foam materials such a polyurethanes could be used. As produced, the expanded plastics material is in the form of a planar board having a metallic foil, for example of aluminium, bonded to each major surface.

Ducting, typically of rectangular cross section. may be produced therefrom in known manner, for example by producing Vee cuts through one foil and the expanded plastics interior, and folding.

As opposed to conventional ducts formed of metal sheet, the product is light, with good thermal insulating properties, and often sufficiently rigid per se for the intended use (although further strengthening measures can be taken in this respect if necessary, for example when requiring long unsupported spans, large cross-sectional areas, or significant differential pressures between interior and exterior). However, a problem arises as to how firmly and efficiently to couple a length of duct so formed either to a further length thereof, or to ancillary equipment such as a fan.

The present invention provides a flange system for assembly at an edge of a board, comprising first and second elongate portions, said first portion comprising a first elongate web, and a sole elongate second web extending from one side of the first web to provide a member of L-shaped crosssect ion, and said second portion comprising third and fourth elongate webs providing an L-shaped cross-section, and a fifth web extending from the third web in spaced relation to, and generally parallel to, the fourth web to form with the fourth web an insert ion channel for reception of at least a free elongate edge portion of the second web, the insert ion channel and the said free portion being adapted for frictional engagement.

Preferably the fifth web is adapted for providing the frictional engagement with the free portion. The frictional engagement may be provided by raised portions on the interior surface of the channel and/or on the free portion, and preferably on the surfaces of both parts where one overlies the other when the two portions are assembled about the board edge. In a preferred embodiment the frictional engagement is provided by elongate ribbing on at least one surface of the free portion and the corresponding internal surface(s) of the insertion channel, and preferably this ribbing is formed on the fifth web.

Preferably (a) the second web has a width substantially equal to, or slightly less than, the thickness of the board for which the flange system is intended.

Preferably (b) the fourth web has a width which is at least substantially equal to the board thickness and/or the fifth web has a width substantially equal to, or slightly less than, the thickness of the board for which the flange system is intended. Most preferably the fourth web 4 has a width which is at least substantially equal to the board thickness and the fifth web 5 has a width which is substantially less than the board thickness (e.g. 30-60k thereof).

Advantageously both the preceding conditions (a) and (b) apply, so that both the second and the fourth/fifth web substantially co-extend across the bottom of the U-shaped channel formed by the assembled first and second flange portions.

Preferably either or (advantageously) both the first and third web are adapted for frictional engagement and/or deformation of the board, such as by being provided with raised portions. In a preferred embodiment, these raised portions are in the form of at least one longitudinal rib internally of the L-shaped cross-section, but other means, for example the provisions of inwardly projecting tangs which deform or pierce the metal foil, are possible.

One or both said portions may be formed of metal, e.g.

aluminium or an aluminium alloy. Particularly where there is a need to prevent thermal conduction between the interior and exterior of the duct (such as to avoid condensation on the exterior of cooled ducting in warm climates), at least one flange portion, preferably the second flange portion, may be made of material which is relatively thermally insulating, such as a plastics material.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figures 1 and 6 illustrate a second flange portion in cross-section; Figure 2 illustrates in cross-section four different first flange portions to which the second flange portion may be assembled, and the resulting assemblies; Figure 3 illustrates the manner of cutting necessary on the first flange portion for use on ducting; Figure 4 illustrates another flange system in crosssection, as applied to a board edge; and Figure 5 is an enlargement of part of Figure 2(a).

As shown in Figure 1, a second flange portion comprises a third elongate web 3 from which extend fourth and fifth parallel spaced webs 4, 5 which define an insertion channel 6, the web 4 being at or adjacent an edge of web 3. The internal surface of channel 6 defined by web 5 is provided with longitudinal ribs, for example on an thickened edge portion of web 5. Web 4 has a width generally equal to the thickness of board with which it is intended to be used, and while web 5 can have a substantially lesser width (e.g.

40-60%, around 50% as shown), this need not be the case.

This second flange portion can be used with a variety of first flange portions, four of which are shown in Figure 2, and each of which comprises a first elongate web 1 from which one side of which extends a sole second web 2 so as to provide an L-shape cross-section. The free edge of web 2 is enlarged, and comprises longitudinal ribs on the side which cooperates with the web 5, thus providing frictional engagement. As shown in Figure 5 (corresponding to Figure 2(a)) and Figure 6, the cooperating ribs may be of complementary saw-tooth form, thus providing a ratchet effect upon assembly.

Each of webs 1 and 3 is provided with internally facing ribs. As shown, there is a rib 7 on the face of the web, and another rib 8 is formed at the edge of the web.

In use, the first and second flange portions are placed either side of a board edge and squeezed together in a direction transverse to the board thickness so that the web 2 enters channel 6 and is held there by friction and/or engagement of the associated ribs. At the same time, the ribs 7, 8 frictionally engage and/or deform the major surfaces of the board to secure the assembly thereon.

When applying the flange system to the end of a duct, the second flange portion will form the interior member. For a rectangular cross-section duct, four lengths will be cut to line the internal edge area, allowing for metal thicknesses. In a preferred method of use, the first flange portion will be in one piece, Vee cuts being made as illustrated in Figure 3 to permit it to be bent about the outside of the duct. The second flange portions are then assembled to the first portion. Nevertheless other methods of use are possible - for example, the outer member may also be of four cut lengths, with additional corner pieces being applied to complete the assembly.

The first flange portion may be plain, as illustrated in Figure 2(b), for example for completing a duct end.

However, it may be provided with other portions, enabling assembly to other ducts or apparatus. Figure 2(a) illustrates a further channel piece 9 extending from the web 1; when two ducts so provided are abutted, channels may be slid over adjacent channel pieces to couple the ducts together (this is known as a bayonet fitting).

Figure 2 (c) shows a web 10 which is generally coplanar with web 1 but extends on the other side of the web 2. Figure 2(d) shows a web 11 which is coplanar with the sole web 2 but extending on the other side of web 1. Clearly either of these webs can be adapted to engage with other apparatus using suitable fastening means such as rivets or bolts.

Figure 4 illustrates the form and application of an earlier type of two-part flange system. This differs from that shown in Figures 1 and 2 in that (a) the second flange portion comprises a further web extending parallel to web 2; and in that (b) neither of webs 2 and 4 is substantially coextensive with the edge of the board. It was found that, in practice, the further web of the second flange portion has no mechanical function. Furthermore, its provision makes it difficult to increase the width of the web 4 of the first portion. In addition, and perhaps more importantly, when there is only a single web in which it is necessary to form Vee cuts (as when applied to a duct end), these cuts can be made by stamping. This is a relatively cheap and rapid process which is applicable to the embodiments of Figures 1 and 2, but cannot be applied when more than one web needs to be cut at the same time, as in Figure 4.

The increased overlap with the board edge provided by widening the flange 2 or 4, and the increased overlap with each other when both are widened, increases the strength of the assembled duct and flange, and, by providing greater resistance to opening of the sides of the U of the assembled flange portions, reduces the chance of disengagement of the assembled flange with the board.

Claims

CLAIMS:

1. A flange system for assembly at an edge of a board (or panel), comprising first and second elongate portions, said first portion comprising a first elongate web, and a sole elongate second web extending from one side of the first web to provide a member of L-shaped cross-section, and said second portion comprising third and fourth elongate webs providing an L-shaped cross-section, and a fifth web extending from the third web in spaced relation to, and generally parallel to, the fourth web to form with the fourth web an insertion channel for reception of at least a free elongate edge portion of the second web, the insertion channel and the said free portion being adapted for frictional engagement.

2. A flange system according to claim 1 wherein the fifth web is adapted for providing the frictional engagement with the free portion.

3. A flange system according to claim 1 or claim 2 wherein the frictional engagement is provided by raised portions on the interior surface of the channel and/or on the free portion.

4. A flange system according to claim 3 wherein the raised portions are provided on the surfaces of both parts where one overlies the other when the two portions are assembled about the board edge.

5. A flange system according to any preceding claim wherein the frictional engagement is provided by elongate ribbing on at least one surface of the free portion and the corresponding internal surface(s) of the insertion channel.

6. A flange system according to claim 5 wherein the ribbing is formed on the fifth web.

7. A flange system according to any preceding claim wherein the second web has a width substantially equal to, or slightly less than, the thickness of the board for which the flange system is intended.

8. A flange system according to any preceding claim wherein the fourth web has a width which is at least substantially equal to the board thickness.

9. A flange system according to any preceding claim wherein the fifth web has a width substantially equal to, or slightly less than, the thickness of the board for which the flange system is intended.

10. A flange system according to any preceding claim wherein either or both the first and third web are adapted for frictional engagement and/or deformation of the board.

11. A flange system according to any preceding claim wherein the first and or third webs are provided with raised portions for frictional engagement and/or deformation of the board.

12. A flange system according to claim 11 wherein said raised portions are in the form of at least one longitudinal rib internally of the L-shaped cross-section.

13. A flange system according to claim 11 wherein said raised portions are inwardly projecting tangs.

14. A flange system according to any preceding claim wherein at least one said portion is formed of metal.

15. A flange system according to claim 14 wherein said metal is aluminium or an aluminium alloy.

16. A flange system according to any preceding claim wherein one said portion is of a plastics material.

17. A flange system according to claim 16 wherein said one portion of plastics material is said second portion.

18. A flange system substantially as hereinbefore described with reference to Figures 1 to 3, 5 and 6 of the accompanying drawings.

19. A duct of polygonal cross-section, formed of rigid foamed plastics material, and having assembled thereto at its end a flange system as claimed in any preceding claim.

20. A duct according to claim 19 wherein said first web is located on the duct exterior surface and said third web is located on the duct interior surface.

21. A duct according to claim 20 wherein one said first portion has bends in said first web so as to be assembled to a plurality of sides of said polygonal-cross section.

22. A duct according to claim 21 wherein said second web has Vee cuts at said bends.

23. A duct according to any one of claims 19 to 22 wherein respective said second portions are located on sides of said polygonal-cross section.