IES86202B2 - A tubular duct member - Google Patents

Abstract

A tubular duct member comprises a plurality of circumferential sheet metal panels (12) joined along adjacent longitudinal edges by connectors (14) which engage in respective folded sheet metal slots (16) formed along said longitudinal edges. <Figure 1>

Description

S 8 6 2 Ο 2 S 1 30 0 1 Ο A Tubular Duct Member Field of the Invention This invention relates to a tubular duct member, i.e. a length of duct of which a number can be joined end to end to form tubular ducting for, e.g., heating, ventilation and air conditioning (Η-Vac) systems.

Background to the Invention Typically, ducting is fabricated and assembled in a workshop. It is then shipped to site, where it is combined with fittings such as reducers, T-pieces, bends, elbows, etc., to form air and gas distribution systems.

The disadvantages of the existing products are: - In the workshop fabrication process, a number of machines such as guillotines, press brakes and seamers are used, together with processes such as cutting and welding, making handling and forming expensive.

- Once made, storage, handling, road haulage and shipping costs can be high, because of the significant volumes taken up by large duct cross sections.

- Offloading, storage and on-site handling to the point of installation is also costly.

Prior Art The following documents disclose lengths of duct manufactured by joining individual panels with male and female members that are push-fitted together: S86203L 1. JP 2003214692 A (FUKAGAWA) see figures 1-3 and 8 in particular, and also the English language abstracts. 2. JP 5172281A (EE Ο Y SYST KENKYUSHO) see figures 1-3 in particular, and also the English language abstract. 3. JP 58006351 A (KAJIWARA) see figure 5 in particular, and also the English language abstract. 4. US 2005/0109415 Al (SNYDER) see whole document.

. US 2847034 (SWETT) see whole document 6. DE 1957274 Al (BRINKMANN) see whole document, especially figures 1-3. 7. EP 0071586 Al (GRIMALDI) see whole document.

Documents 1 to 4 disclose the use of small projections for retaining male members in female members to fix edges together.

Documents 1 to 3 in particular relate to ducting having a rectangular cross-section.

In document 5, the metal panels are resilient to a degree, so that the panels are sealed with respect to each other when assembled. The panels are joined by pushing a male member into a female member.

Document 6 (paragraph bridging pages 5 and 6) indicates that an adhesive may or may not be used in the joint between the male and female members.

Document 7 discloses ducting formed from more than one panel, which are joined by being joined by hooking one member within the other (and vice-versa). This document shows stacking to transport the individual parts to the site for assembly.

Tubular duct members and methods of making them are described in our copending patent applications W02010094385 and WO2012022594. The present invention relates to improvements and/or alternatives to the techniques described therein.

Summary of the Invention The invention provides a tubular duct member comprising a plurality of circumferential sheet material panels joined along adjacent longitudinal edges by connectors which engage in respective folded sheet metal slots formed along said longitudinal edges.

Preferably, each slot has a relatively narrow throat which communicates with an enlarged base, and each connector has a main body portion with opposite enlarged heads, each enlarged head being compressible laterally inwardly to pass through the throat of a respective slot and after passing through the slot to resiliently expand laterally outwardly such that respective detent surfaces in the slot and on the connector head engage behind one another to retain the edges of the panels together.

Brief Description of the Drawings An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view (not to scale) of a tubular duct member according to the embodiment of the invention.

Figure 2 is a cross-section through one of the folded sheet steel panels used in the duct member of Figure 1 (all four panels being the same).

Figure 3 is a cross section of a connector used to join adjacent edges of the sheet steel panels in the assembled duct member. ί Figure 4 is an enlarged cross section through the corner of the duct member circled in Figure 1 (all four corners being the same).

Description of Embodiment of the Invention Referring to Figures 1 to 4, a tubular duct member 10 of substantially rectangular cross-section is assembled from opposite pairs of substantially flat sheet steel panels 12 defining the outer circumference of the duct member. While the embodiment employs steel panels, it will be seen that the invention is applicable to any suitable metal or non-metal material. The panels 12 are joined edge to edge along adjacent longitudinal edges by connectors 14 which engage in respective slots 16 formed along said longitudinal edges. As shown in Figure 2, each panel 12 in formed as a shallow tray with opposite sidewalls 18 which are inclined inwardly at 45 degrees. Each slot 16 is formed in a respective sidewall 18. It will be appreciated that in Figures 2 to 4 the components there shown are highly elongated in the direction normal to the figure.

In the embodiment, each panel 12 is formed generally in the manner described in WO2012022594 by feeding sheet metal continuously from a roll and progressively folding the opposite edges of the sheet as it advances to form the sidewalls 18 having the slots 16. Where a non-metal, in particular, is employed, this might be extruded rather than progressively folded. A thermal insulator in flowable form is dispensed into the continuous shallow tray thus formed as the sheet advances so that the thermal insulator spreads out to fill substantially the full width of the tray between the sidewalls 18, the liquid thereafter solidifying to form a solid thermally insulating layer 20 (not shown in Figure 2). The continuously formed sheet is cut transversely into individual panels 12.

Each slot 16 has a relatively narrow throat 22 which communicates with an enlarged trapezoidal base 24, and each connector has a generally L-shaped or right-angled main body portion 26 with enlarged arrow-like heads 28 at opposite ends. Each head 28 has a pair of rearwardly and outwardly extending arms 30 which are compressible laterally inwardly to allow the head 28 pass through the throat 22 of a respective slot 16 and after passing through the slot to resiliently expand laterally outwardly in the base 24 such that respective detent surfaces 32, 34 in the slot and on the connector head engage behind one another to retain the edges of the panels together. The connector 14 may be hollow or an integral moulding of solid plastics material, or (as shown) it may have a core of a different material, such as a thermal insulator or a metal.

Prior to inserting the connector 14 into each slot 16, a body 36 of resilient material is inserted in the base 24 of each slot 16 and this is compressed against the connector head 28 to maintain the detent surfaces 32, 34 bearing against one another.

Finally, each sidewall 18 includes a body 38 of resilient material compressed between the edges of the panels to seal the join between the two.

The invention is not limited to the embodiments described herein which may be modified or varied without departing from the scope of the invention.

Claims (5)

Claims

1. A tubular duct member comprising a plurality of circumferential sheet material panels joined along adjacent longitudinal edges by connectors which engage in 5 respective folded sheet metal slots formed along said longitudinal edges.

2. A tubular duct member as claimed in claim 1, each slot having a relatively narrow throat which communicates with an enlarged base, and each connector having a main body portion with opposite enlarged heads, each enlarged head being 10 compressible laterally inwardly to pass through the throat of a respective slot and after passing through the slot to resilient ly expand laterally outwardly such that respective detent surfaces in the slot and on the connector head engage behind one another to retain the edges of the panels together. 15

3. A tubular duct member as claimed in claim 2, in which the base of each slot includes a body of resilient material compressed against the connector head to maintain the detent surfaces bearing against one another.

4. A duct member as claimed in claim 1, 2 or 3, further including a layer of 20 thermally insulating material lining the inside surfaces of the panels.

5. A duct member as claimed in any preceding claim, further including at least one body of resilient material compressed between the edges of the panels to seal the join between the two.