GB2393508A

GB2393508A - Duct accessory featuring perforated attachment flanges

Info

Publication number: GB2393508A
Application number: GB0316850A
Authority: GB
Inventors: Owen Michael Ferry
Original assignee: DUCTFORM VENTILATION
Current assignee: DUCTFORM VENTILATION
Priority date: 2002-07-20
Filing date: 2003-07-18
Publication date: 2004-03-31
Anticipated expiration: 2023-07-18
Also published as: GB2393508B; GB0316850D0; GB0216887D0

Abstract

An accessory suitable for use with a duct, the accessory featuring a body portion with an opening, at least one side wall 2A-D and at least one connecting flange 10 adjacent the opening. The flange 10 being integrally formed with the side wall 2A-D and featuring a plurality of perforations 14 dividing the flange 10 into first 10A and second 10B flange portions. The perforations 14 allowing the first flange portion 10A to be pivoted or bent relative to the second flange portion 10B. The first 10A and second 10B flange portions may be bent or folded into a position in which the first 10A and second 10B flange portions are substantially parallel. There may be provided four connecting flanges 10 each integrally formed with a respective side wall 2A-D. The perforations 14 of each flange 10 may run parallel to the plane of its respective side wall 2A-D. The accessory may be provided with a removable access door (20, figure 3). The accessory may be formed from a single sheet of stainless steel shaped by a punching operation or laser or plasma cutting. The accessory may be held in a square form using a tab 17 and slot 19 arrangement.

Description

\ ) 1 DUCTWORK ACCESSORIES

1 The present invention is directed to accessories 2 which are fitted to ductwork, particularly for use 3 in forced-air ductwork installations.

5 With ducts for use in forced-air ducting 6 installations, it is often necessary to fit 7 accessories such as, for example, access doors or 8 branch ducts. At present, such accessories are 9 fixed into apertures in the ducts either by 10 mechanical fixings and/or welding prior to 11 installation of the duct system in a building. This 12 not only has disadvantages in terms of time and cost 13 of production, but also in terms of increased noise 14 levels in the manufacturing environment. It would 15 therefore be advantageous to provide accessories 16 which may be fixed to the ducts without the need for 17 mechanical fixings or welding.

19 One proposed solution has been to provide a number 20 of metal tabs on the accessory which can be received 21 in one or more apertures on the duct. The tabs can 22 then be bent over to hold the accessory in place.

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e ace 1 However, given the thickness of the sheet metal used 2 for such accessories, the tabs must be bent using 3 hammers or such like to provide the necessary 4 bending force, which again limits the time savings 5 and noise reduction during manufacture.

7 It is an aim of the present invention to obviate or 8 mitigate one or more of the aforementioned 9 disadvantages.

11 According to a first aspect of the present 12 invention, there is provided an accessory for a 13 duct, the accessory comprising: 14 a body portion having an opening at at least 15 one end thereof and at least one side wall which 16 defines a passage from the opening through the body 17 portion; 18 at least one connecting flange adjacent the 19 opening, the flange being integrally formed with the 20 side wall; 21 wherein the connecting flange is provided with 22 a plurality of perforations which divide the flange 23 into first and second flange portions, the 24 perforations allowing the first flange portion to be 25 pivoted relative to the second flange portion.

27 Preferably, the perforations allow the first flange 28 portion to be pivoted into a position in which the 29 first and second flange portions are substantially 30 parallel.

::: ee. Àe c:e À.e:e . J 3 1 Preferably, the accessory has first and second pairs 2 of side walls such that the accessory is 3 quadrilateral in cross section, the accessory having 4 four connecting flanges which are each integrally 5 formed with a respective one of said first and 6 second pairs of side walls.

8 Preferably, the perforations of each connecting 9 flange run substantially parallel to the plane of 10 its respective side wall.

12 In a preferred embodiment, the body portion has an 13 opening at either end thereof. Preferably, at least 14 one opening is provided with an access door.

15 Preferably, the access door is removably attached to 16 the body portion.

18 In an alternative embodiment, one of the second pair 19 of side walls is inclined relative to the other of 20 the second pair of side walls such that the passage 21 is tapered from one end of the body portion towards 22 the other end.

24 Preferably, the body portion, the at least one side 25 wall and the at least one connecting flange are 26 integrally formed from a single sheet of material.

27 Preferably the material is a metal. Most 28 preferably, the material is stainless steel.

29 Preferably, the body portion, the at least one side 30 wall and the at least one connecting flange are 31 formed from the sheet of material by a punching 32 operation. Alternatively, the body portion, the at

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À: e..e. À. ce.: :.. À 1 least one side wall and the at least one connecting 2 flange are formed from the sheet of material by a 3 laser or plasma cutting operation.

5 According to a second aspect of the present 6 invention, there is provided a method of fixing an 7 accessory according to the first aspect of the 8 present invention to a wall of a duct, the method 9 comprising the steps of: 10 positioning the accessory over a corresponding 11 aperture in the wall of the duct such that the 12 plurality of perforations in the at least one 13 connecting flange are substantially aligned with a 14 respective edge of the aperture; 15 pivoting the first flange portion relative to 16 the second flange portion about the perforations 17 such that the first flange portion pivots into the 18 aperture of the duct; and 19 continuing to pivot the first flange portion 20 until it abuts an internal surface of the duct wall 21 and the first and second flange portions are 22 substantially parallel.

24 Preferred embodiments of the present invention will 25 now be described, by way of example only, with 26 reference to the accompanying drawings, in which: 28 Figure 1 shows a plan view of a blank for 29 forming a duct access door frame; 31 Figure 2 shows a projection view of the frame 32 once formed from the blank of Figure 1;

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À À : e:À:: À :c::À À .. j 5 2 Figure 3 shows a partial cut away view of a 3 duct access door; 5 Figure 4 shows a cross sectional view of the 6 duct access door of Figure 3 when installed on a 7 duct; 9 Figure 5 shows a projection view of a branch 10 duct; and 12 Figure 6 shows a schematic view of the branch 13 duct of Figure 5 when installed on a duct.

15 Figure 1 shows the blank from which a duct access 16 door body, or frame, 1 is formed. The blank is 17 punched from a sheet of stainless steel in a 18 punching machine and comprises four elongate panels 19 2A2D which are integrally formed with one another 20 longitudinally. The extent of each panel 2 is 21 defined by three fold lines 4 which run laterally 22 across the panels 2A-2D. Each of the four panels 23 2A-2D has upper and lower longitudinal edges 8,6 24 upon which are integrally formed upper and lower 25 flanges 12,10, respectively. The lower flange 10 of 26 each panel 2A-2D is provided with a line of 27 longitudinal perforations 14 which run substantially 28 parallel to the lower longitudinal edge 6 of the 29 panel 2A-2D. The perforations 14 effectively divide 30 the lower flanges 10 into first and second lower 31 flange portions lOA, lOB. The lateral edge 16 of the 32 first panel 2A is provided with an integral tab 17

. . À ::: tI. À.:. e.'À:e eve 8 1 which is received in a corresponding slot 19 2 adjacent the lateral edge 18 of the last panel 2D.

4 Figure 2 shows the door frame 1 when formed from the 5 blank of Figure 1. As can be seen, the frame 1 is 6 manually formed into a substantially square shape 7 which is open at either end. Each panel 2A-2D forms 8 a side wall of the frame 1. The upper flanges 12 of 9 each panel, or side wall, 2A-2D are folded inwardly 10 towards the centre of the frame such that they 11 double over to lie flush with the panels 2A-2D 12 themselves. The lower flanges 10 of each panel 2A 13 2D are also folded inwardly towards the centre of 14 the frame 1 until they lie in a plane substantially 15 perpendicular to the planes of the panels 2A-2D.

16 With the upper flanges 12 folded in this way, extra 17 rigidity is afforded to the frame 1. In order to 18 secure the frame 1 in this form, the tab 17 of the 19 first panel 2A is fed through the slot 19 in the 20 last panel 2D. Although not seen in Figure 2, the 21 tab in folded back upon itself once through the slot 22 so as to be securely held.

24 Figure 3 shows the access door in its entirety, with 25 a detachable door 20 fixed to the frame 1 by a chain 26 22 that is fixed at each end to the frame 1 and door 27 20 by screws or rivets 24. The door 20 is 28 substantially square in shape such that it will 29 closely fit within the frame 1. The door 20 is also 30 provided with a pair of conventional rotating 31 catches 26 which engage with corresponding hooks 28

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À 1 fixed to opposite sides of the frame 1 such that the 2 door 20 may be held in the frame 1.

4 Figure 4 shows a schematic cross-section of the 5 access door when attached to a duct 29. Initially, 6 the access door is positioned such that it lies over 7 the corresponding aperture 30 in the duct 29 and the 8 perforations 14 of the lower flanges 14 are 9 substantially aligned with the edges of the aperture 10 30. Once the perforations 14 are aligned with the 11 edges of the aperture 30 in the duct 29, the first 12 lower flange portions 10A are manually folded 13 downwards into the duct aperture 30 about fold lines 14 defined by the perforations 14. The first lower 15 flange portions lOA are pivoted relative to the 16 second lower flange portions lOB until they abut the 17 internal surface 32 of the duct 29, in a plane 18 substantially parallel to that of the second lower 19 flange portions lOB. In this way, the access door 20 is manually fixed to the duct without the need for 21 any additional fixing steps involving mechanical 22 fixings or welding.

24 Figure 5 shows a projected view of a branch duct 50 25 that is to be fixed to ductwork in the same manner 26 as the access door described above. The branch duct 27 50 is provided with body having a first pair of side 28 walls 52 and a second pair of side walls 54A, 54B.

29 The body has an opening at either end thereof. As 30 best seen in Figure 6, one side wall 54B of the 31 second pair is inclined to the vertical such that 32 the passage through the branch duct tapers from the

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1 first end towards the second end. This allows 2 better air flow through the branch duct 50. The 3 inclination of the side wall 54B is facilitated by 4 tapering the edge 56 of each of the first pair of 5 side walls 52 which is adjacent the side wall 54B.

6 The side walls 52, 54A, 54B are arranged such that the 7 branch duct 50 has a substantially quadrilateral 8 cross-section when viewed in horizontal section.

9 Each of the side walls 52, 54A, 54B has an upper edge 10 57 which has an integral upper flange 58. The upper 11 flanges 58 are provided such that further components 12 may be attached to the branch duct 50.

14 The branch duct is formed from a stainless steel 15 sheet which is punched in a punching machine, as 16 with the access door. However, as the branch duct 17 50 is conventional in form aside from certain 18 features which will be referred to below, the l9 assembly of the branch duct 50 itself from the blank 20 prior to fitting to the main duct will not be 21 described in detail here.

23 As with the access door, the lower edges 59 of each 24 side wall 52, 54A, 54B are provided with integral 25 lower flanges 60 which project inwardly in a plane 26 substantially perpendicular to the planes of the 27 side walls 52, 54A, 54B. Each lower flange 60 is 28 provided with a line of perforations 62 running 29 substantially parallel to the plane of its 30 respective side wall 52, 54A, 54B along the length of 31 each lower flange 60. As with the access door, the

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À....DTD: J 1 perforations 62 divide the lower flanges 60 into 2 first and second lower flange portions 60A,60B.

4 Figure 6 shows in schematic form how the branch duct 5 50 is fixed to the main duct 29. As with the access 6 door, the branch duct 50 is positioned over the 7 aperture in the main duct 29 such that the edges of 8 the aperture align substantially with the 9 perforations 62 in the lower flanges 60 of the 10 branch 50. In this way, once the branch 50 is put 11 into position, the first flange portions 60A of the 12 lower flanges are manually folded downwards along 13 the perforations 62 into the aperture of the main 14 duct 29. The second flange portions 60A are folded 15 until they abut an internal surface 32 of the duct 16 29, in a plane substantially parallel to that of the 17 second flange portions GOB. In this way, the branch 18 duct 50 is manually fixed to the main duct 29 19 without the need for any additional fixing steps 20 involving mechanical fixings or welding.

22 The thickness of the metal used to fabricate the 23 accessories is preferably in the range 0.5mm-lmm, 24 with 0.8mm being the ideal thickness. If the metal 25 is any thicker than lmm the steel cannot be bent by 26 hand, as required by the invention.

28 The present invention allows duct accessories such 29 as the examples described above to be fixed to a 30 duct in a cheaper and quicker manner than 31 conventional methods allow. As no mechanical fixing 32 or welding steps are required, the noise generated

::: ee. cee. c: te t'::e . 1 during installation of the present invention on a 2 duct is also significantly reduced.

4 Although the specific examples above refer to access 5 doors and branch ducts, the present invention is not 6 limited to those accessories, but instead may be 7 applied to any accessories currently fixed to ducts 8 by mechanical fixings or welding. Such accessories 9 may have body portions where only one opening is 10 present, such as housings for heating or cooling 11 equipment, for example. Although the accessories 12 described above are formed from punched blanks, it 13 will be understood by those skilled in the art that 14 the blanks may also be produced using other methods 15 such as cutting in a laser or plasma cutting 16 machine.

18 Furthermore, although the preferred embodiments show 19 lower flanges formed integrally with each panel, the 20 accessory need only have one lower flange to be 21 fixed securely to the duct. For a stronger fixing, 22 further flanges may be provided, as shown in the 23 preferred embodiments. Additionally, although each 24 embodiment shown here has a four panels and a 25 quadrilateral cross section, the accessory is not 26 limited to this arrangement and need only have one 27 or more side walls as desired, with the cross 28 section of the accessory being determined by the 29 number of panels. Finally, although the preferred 30 embodiments described herein were manufactured from 31 stainless steel, any other suitable metal may be 32 used, so long as it is of an appropriate thickness.

-. c 2 These and other modifications and improvements may 3 be incorporated without departing from the scope of 4 the invention.

Claims

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ce A:::: c: Claims

1 1. An accessory for a duct, the accessory 2 comprising: 3 a body portion having an opening at at least 4 one end thereof and at least one side wall which 5 defines a passage from the opening through the body 6 portion; 7 at least one connecting flange adjacent the 8 opening, the flange being integrally formed with the 9 side wall; 10 wherein the connecting flange is provided with 11 a plurality of perforations which divide the flange 12 into first and second flange portions, the 13 perforations allowing the first flange portion to be 14 pivoted relative to the second flange portion.

16
2. The accessory of Claim 1, wherein the 17 perforations allow the first flange portion to be 18 pivoted into a position in which the first and 19 second flange portions are substantially parallel.

21
3. The accessory of either Claim 1 or Claim 2, 22 wherein the accessory has first and second pairs of 23 side walls such that the accessory is quadrilateral 24 in horizontal cross section, the accessory having 25 four connecting flanges which are each integrally 26 formed with a respective one of said first and 27 second pairs of side walls.

29
4. The accessory of Claim 3, wherein the 30 perforations of each connecting flange run

e.: ce À À:: te' eve :.e c:e.: 1 substantially parallel to the plane of its 2 respective side wall.

4
5. The accessory of any preceding claim, wherein 5 the body portion has an opening at either end 6 thereof. 8
6. The accessory of Claim 5, wherein at least one 9 opening is provided with an access door.

11
7. The accessory of Claim 6, wherein the access 12 door is removably attached to the body portion.

14
8. The accessory of any of Claims 1 to 5, wherein 15 one of the second pair of side walls is inclined 16 relative to the other of the second pair of side 17 walls, such that the passage is tapered from one end 18 of the body portion towards the other end.

20
9. The accessory of any preceding claim, wherein 21 the body portion, the at least one side wall and the 22 at least one connecting flange are integrally formed 23 from a single sheet of material.

25
10. The accessory of Claim 9, wherein the material 26 is stainless steel.

28
11. The accessory of either Claim 9 or Claim 10, 29 wherein the body portion, the at least one side wall 30 and the at least one connecting flange are formed 31 from the sheet of material by a punching operation.

eeÀe esettee 1
12. The accessory of either Claim 9 or Claim 10, 2 wherein the body portion, the at least one side wall 3 and the at least one connecting flange are formed 4 from the sheet of material by a laser or plasma 5 cutting operation.

7
13. A method of fixing an accessory according to 8 any of Claims 1 to 12 to a duct, the method 9 comprising the steps of: 10 positioning the accessory over a corresponding 11 aperture in a wall of the duct such that the 12 plurality of perforations in the at least one 13 connecting flange are substantially aligned with a 14 respective edge of the aperture; 15 pivoting the first flange portion relative to 16 the second flange portion about the perforations 17 such that the first flange portion pivots into the 18 aperture of the duct; and 19 continuing to pivot the first flange portion 20 until it abuts an internal surface of the duct wall 21 and the first and second flange portions are 22 substantially parallel.

24
14. An accessory for a duct as herein described 25 with reference to the accompanying drawings.

27
15. A method of fixing an accessory according to 28 any of Claims 1 to 11 to a duct as herein described 29 with reference to the accompanying drawings.