AU698521B2 - Split branched duct fitting - Google Patents

Description

ida L 9~~gll r P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

TO BE COMPLETED BY APPLICANT Name of Applicant: Actual Inventor(s): Address for Service: Kmora%^ £na<erk plr- \<£ecWLo\ces PGLYAIRE FTY LTD ADRIAN VAN DIEMEN A.P.T. Patent and Trade Mark Attorneys GPO Box 772, Adelaide SA 5001 SPLIT BRANCHED DUCT FITTING ~sLrD sLcm Invention Title:

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I: r i r r e :i The following statement is a full description of this invention, including the best method of performing it known to us:f L P "IIIIIIL~C- d ~mp t~__l~hl i The present invention relates to a fitting for an air conditioning duct that can be produced as a split item for connecting at or before installation.

Air conditioning ducting is used in the distribution of conditioned air throughout buildings. Generally only one conditioning unit supplies conditioned air to a dwelling.

The conditioned air is directed through a primary duct and is then directed by the use of branch fittings into subsidiary ducts, one or more of which may yet undergo further branching into further subsidiary ducts.

The branch fittings may take on the configuration of a Y shaped branch shape dividing one stream of air into two streams, or the branch may be more complex such as a tree shaped branch. These branch fittings are presently generally blow moulded in plastics, and may have an inlet and outlets stepped in diameter to provide for connection with any one of a few ducts having a variety of diameters.

Such branch fittings are presently integrally moulded as a complete unit. This provides for well formed branch fittings, that are lightweight and robust enough for transport and handling. There is however a major problem for the transport of these fittings, in that the fittings are quite bulky, because the internal diameters are not small and might vary from between 100 mm and 600 mm outlet and inlet sizes. Thus the greatest amount of room is taken up by air during transport, storage and handling and only very few branched fittings can be packed into a carton. The bulkiness of such fittings leads to substantial increases in costs for, storage, transport aw. handling, and discourages the carrying of stocks by tradesmen involved in the fitting of such ducts leading to further S 25 inefficiencies.

A suggestion has been made in Australian Patent application N'j 67316/94 by Westaflex to provide a Y shaped branch fitting that is formed in halves to alleviate the above problem. There are, however, several difficulties associated with this suggestion.

In particular the position of the proposed break in halves of the branch fitting causes a problem forjoining. A single very large length of split is provided and this must be firmly joined along its complete length. Whilst use of adhesives or fasteners that pierce L oo the flanges have been discussed the suggested flanges are quite small so that actual fastening would be quite difficult. Whilst the manner in which the halves are stacked 35 leads to improvements over packaging complete fittings, there are still inefficiencies in the use of space. Furthermore the cutting of blow moulded items in half is one that i requires some precision because of the length of the split.

I .I i It is an object of this invention to provide a split and nestable branch fitting for air conditioning ducts that obviates or minimises at least one of the aforementioned problems in a simple yet effective way, or at least provides the public with a useful choice.

In a broad form and not necessarily the broadest or only form the invention could be said to reside in a branch fitting for an air conditioning duct the branch fitting comprising a central portion, and at least three air passageway apertures leading away from the central portion, including an inlet aperture and at least two outlet apertures, and thereby including at least three corresponding inter-apertural regions between adjacent sides of adjacent apertures, the branch fitting and each aperture is split longitudinally in the direction of airflow to form two parts which two parts can be nested within the other, and fastening means fastening together the two parts at each of the inter-apertural regions.

Preferably at least one pair of adjacent protrusions are formed at each of the apices S within the inter-apertural regions, a first of the pair being formed on a first of the parts, and a second being formed on a second of the parts, the fastening means at least 20 fastening together the at least one pair of protrusions for each of the inter-apertural regions to thereby join the two parts together.

It may be preferred that at least three tubular portions extend from the central portion, the three tubular shaped portions including a tubular shaped inlet and at least two 25 tubular shaped outlets, each tubular portion having at a free end a respective aperture leading away from the branch fitting. It will be appreciated that the inter-apertural regions will include parts of the tubular portion and the central portion.

The two parts are preferably formed as approximately equal halves of the branch fitting, and thus more than two equal half parts may be stacked together in a container.

The protrusions are preferably positioned so that when they are held together the two parts are held against each other directly.

The branch fitting may take a number of forms and at the inter-apertural regions take on a considerable range of shapes, some include more acute or complex shapes and yet i O4 Ie 'N 4 ~e others have very simple and shallow curves. The protrusion and fastening means may be tailored to suit the particular inter-apertural region of the branch fitting.

It is preferable that the protrusion formed at the apices extends externally of the branch fitting. It may still be desired to have the protrusions extending internally of the branch fitting, and that would still be technically feasible because many of the fittings are of a relatively wide diameter.

The protrusions are preferably in the form of flanges.

Each of the flanges may extend along the fitting for a short distance and may, for example extend as a simple flat tab. The fastening means may be a sprung metal clip, with two legs oppositely sprung with respect to one another so that when clipped over a pair of abutting flanges the flanges are held together by the clip. For the clipping to act effectively the depth of the pair of flanges is preferably greater than the thickness of the two abutting flanges. It may be desired to provide a unevenness on the flange so as to minimise the risk of the clip slipping from the flange. The unevenness may take the form of a bead at the exposed edge each of the pair of abutting flanges.

Whilst the use of a clip of the sort described above is desirable, because it can be put into place during installation of the duct in, for example, a ceiling with minimum effort, Sother fasteners may also be provided for. For example the use of a fastener that penetrates through both of the pairs of flanges, for example a pop rivet is provided for.

I s 25 The strength of the fasteners need not be extreme because the fastener does not need to be the sole means for withstanding strains that might be placed on the fitting after installation. The configuration of splitting each of the tubular portions of the fitting provides that the strength of any fastening means is supplemented by the positioning of at least three ducts, which join over the end parts of the tubular elements of the fitting so that the fitting is further prevented from being broken apart by the ducts.

The provision of a clip fastener of the type discussed above has an advantage in that a quite short flanges may be conveniently used especially for branch fittings where the inter-apertural regions do not provide a smooth surface, for example where ridges or other complex outside shapes of the fitting are present at the inter-apertural region or where the it forms a relatively acute angle. However in other fittings longer flanges may also be provided. Such flanges also preferably extend from the outside of the

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fitting and extend between the tubular portions of the fitting and away from a portion of the tubular parts intended for connection with a duct.

The longer flanges may be connected by means of several clips, or alternatively a slide-on fastener may be provided. In the latter alternative the flange may include a rail at a free edge of the flange, the slide-on fastener sliding over the flange. The free edge may be provided as being either straight, or convex, however, preferably the free edge of the flange i- concave, so that the sliding fastener can be fitted more easily. The slide-on fastener may be made of somewhat flexible plastics material, however more preferably the slide-on fastener is of a more rigid plastics or other material such as metal, with a curved shape along its length that corresponds to the shape of the rail on the flange.

In an alternative form the protrusions are simply in the form of lugs, through which can pass a fastener. The fastener in this form of protrusion may take the form of a wire passing through the protrusion which wire is then twisted to hold the two halves together.

20 In one preferred form the two parts of the branch fitting include a circumferential S, 20 overlap at the longitudinal split whereby a fastener can be passed through the overlap to S. secure the two parts together. An edge of one of the parts adjacent the longitudinal split overlaps an edge of the second of the parts adjacent the longitudinal split.

Preferably a location means is provided on one or both of the parts, to limit the extent 'i 25 of overlap.

The overlap may be limited to the tubular portions of the branch fitting, with no P, circumferential overlap being provided at the apices of the branch fitting.

This arrangement permits simple fasteners to be used to fasten the two parts together.

Such fasteners might be a pop rivet, or a self tapping screw.

In a second broad form the invention couid be said to reside in a method of forming a branched fitting for an air conditioning duct the branch fitting comprising a central portion and at least three air passageway apertures leading away from the branch fitting, including an inlet aperture 1i ,j 6 and at least two outlets apertures, and thereby including at least three corresponding inter-apertural regions between adjacent sides of adjacent apertures, said method including the step of blow moulding or rotor moulding said branch fitting, depressions being formed in a mould used so as to form a protrusion in each of said inter-apertural regions, which protrusion ,an be split after the step of blow moulding to form two protrusions for adjacent location on assembly, said method further including the step of splitting the branch fitting and each of the apertures in the direction of airflow to form two parts which can be nested within the other the step of splitting including the splitting of the protrusion to form two adjacent protrusions.

Preferably the protrusions includes separate upright plastics portions, that are separated during the splitting process, and these upright plastics portions may be joined at an outer extremity by a further web of plastics formed during the blow moulding step, which web is split during the step of splitting. Preferably the further web is substantially removed during the step of splitting.

Preferably the protrusions have a depth greater than their widths.

In a third broad form the invention could be said to reside in a mould for the method of the second broad form of the invention.

In a fourth broad form the invention could be said to reside in one of said parts of the 25 above branched fitting.

To assist with the understanding of the invention one embodiment is illustrated. It is to be understood from the foregoing that the illustrated embodiment of the invention is 3 merely illustrative and in no way restricts the scope of the invention.

In the illustrations: f. Figure. 1 is a side view showing a first embodiment of the invention w: two parts of the branch fitting joined togetber with three ducts, shown in part, joined to the ends of 35 the tubular portions of the fittinl,, 7 Figure 2 is a cross sectional view through II-II showing an abutting pair of flanges of the two parts of the fitting held together by a clip, Figure 3 is a part sectional perspective view of the first embodiment showing the position of a clip relative to the two hal. and the manner in which the duct assist in holding the split fitting together, Figure 4 is a plan view showing a second embodiment of the invention with two parts of the branch fitting joined together with three ducts, shown in part, joined to the ends of the tubular portions of the fitting, Figure 5 is a cross sectional view through V-V showing an abutting pair of flanges of the two parts of the fitting held together by a clip, and Figure 6 is a cross sectional view through a protrusion after blow moulding and during splitting, Figure 7 is a perspective view of the first ,mbodiment of the invention, showing the S* two parts of the branch fitting joined together, showing respective ducts distanced from respective ends of the branch fitting, C C t S Figure 8, is a plan view of a third embodiment showing a branch fitting with three €outlets,

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Figure 9 is a plan view of a fourth embodiment showing a branch fitting with four outlets, 5555 Figure 10 is a side view the assembled branch fitting of a fifth embodiment, tt showing the relative position of the tubular branches, and the central portion, Figure 11 is a perspective view of one side of the assembled branch fitting of the fifth embodiment showing a view of one of the apexes and showing two tubular portions extending away from the apex, Figure 12 is a cross sectional view through 12 12 of Figure 11 showing detail of the overlap and locating means to determine the degree of overlap, i 1 I 8 Figure 13 is a cross sectional view t trough 13 13 of Figure 11 showing detail of the overlap in the apex, Figure 14 is a cross sectional view from a similar aspect of a corresponding sixth embodiment of the invention, and Figure 15 is a cross sectional view taken through the whole of a tubular portion of ducting fitting as joined together.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

Dimensions of certain of the parts as shown in the drawings may have been modified and/or exaggerated for the purposes of clarity of illustration.

The branch fitting of the first and second embodiments comprise a central portion (1) and three tubular portions 3, which tubular portions comprise an inlet tubular portion (2a) and two outlet tubular portions (3 and 4) the free end of each tubular portion including an aperture leading away from the branch fitting for air passage S 20 therethrough. This configuration leads to three apices 6, 7) between adjacent sides of adjacent tubular portions. It can be seen that inter-apertural regions extend between adjacent sides of adjacent apertures and include parts of the tubular portion. Each of the tubular portions includes an end part 9, 10) for receiving a respective duct (11, a, 12, 13).

The branch fitting and each of the tubular portions are split longitudinally in the direction of air flow (shown by arrow 14) to form two parts (15, 16) of the fitting with a longitudinal split therebetween The two parts can be nested together, and the illustrated emt -Aiments show the two parts as being equal halves of the fitting.

t t A pair of adjacent protrusions (18) is formed, in all the illustrated embodiments, at each of the apices within the inter-apertural regions, each protrusion of the pair is abutting in the illustrated embodiments. Fastening means (20) hold the two adjacent protrusions ogether.

In the first illustrated embodiment the protrusions are in the form of short flanges or tabs extending externally from the central portion of the branch fitting. One of the 7- 9 protrusions extends from one of the parts, and another of the protrusions extends from the other of the parts.

Two types of fasteners are provided in the illustrated embodiment. Staples (50) are used to staple together the end ,arts of the tubular portion, and the fastening means at the apices takes the form of a sprung clip (51) having two oppositely sprung legs (21, 22). The sprung legs each bears against a respective one of the two tabs to hold the two tabs together, and when all three clips are in place the two parts of the fitting are held firmly together. The tabs may have unevennesses formed on their outside surfaces, for example in the form of a longitudinal bead. The unevenness assist to retain the clips in place. The clips can simply be put into position over paired tabs by a suitable hand tool.

It is to be understood that it may be desired only to use staples, to fasten the two parts together, in which case, protrusions need not be formed. Alternatively it may be desired not to use staples at all but simply to use spring clips or other fasteners that fasten the two adjacent protrusions together. It may also be desired to use sprung clips over the longitudinal split on the end parts of the outlets.

S' In the second illustrated embodiment, the apices 6, and 7) and the inter-apertural S 20 regions are less acute than those of the first illustrated embodiment and take on a shallow concave shape. A rail as best seen in Figure 5, is formed at the edge of each of the protrusions F the fitting. The protrusions in this embodiment are elongate, extending some way along the respective apices. The rail is kept clear of the ends of the tubular portions, so that the rail and slide-on fastener do not interfere with positioning of the duct over the ends of the tubular portions of the fitting.

A slide-on fastener is provided in this embodiment, the slide-on fastener (52) is made of a semi rigid plastics extrusion and includes an upper flat portion (30) lying against the outer periphery of the pair of protrusions, two legs (31, 32) extending over the rails, I 30 and inwardly extending ledges (33) to fit beneath the rails. The slide on fasteners are simply slid over the rails formed by abutting adjacent protrusions, to hold them together. Staples (50) are used to join the end parts of the tubular portions together.

It is to be understood that a combination of different fasteners may be used for a single fitting, and that the invention has application for a number of different branch fittings, including branch fittings with multiple outlets such as shown in Figure 8 where three outlets are shown. Figure 8 shows the inter-apertural regions joined by two different I.

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fasteners, the acute apices being joined by clips (51) by joining adjacent tabs of the type shown in Figures 1 and 2, and the oblique apices being joined by slide on fasteners (52) of the type shown in Figures 4 and 5. Figure 9 shows a fitting with four outlets, the acute apices being joined by spring clip fasteners of the type shown in Figures 1 and 2, the remainder of the longitudinal splits are joined by staples In use, individual parts of the fitting are provided nested together in a container, such as a cardboard box. The individual parts of the fitting can be carried to the work location, and can be assembled on site. Two parts of the fitting are positioned together, and the fastening means are positioned onto the protrusions of each of the apices. The ducts are then placed over the ends of the tubular portions of the fitting, to further secure the two parts of the fitting together. The illustrated ducts J the type that include a helically wound reinforcement. The ends of the tubular portions of the fitting include barb shaped protrusions (35) that can engage the duct and maintain it in position.

Alternatively and perhaps more preferably the individual parts would be shipped from the manufacturing facility to regional distribution outlets, and joined to form the complete branch fitting at the distribution outlets for on sale to fitters or assembled by the fitters themselves on site.

The preferred method of making the fitting is to blow mould the fitting in a mould I g using a plastics material. A depression is formed in the mould at each of the apices so as to form a protrusion. The depression is formed to give a shape that con ,ponds to CC: the protrusion to be formed. In the illustrated embodiments the depression is deeper C than it is wide, and the blow moulding forms a slot in the protrusion so formed. The protrusion in this form accordingly includes two plastics walls (40, 41), that are ec. separated at an outer edge by a l,"cral joining web (43) of plastics. The width of the Coc slot and hence the lateral web is quite narrow, so that on, cutting the web is substantially removed, leaving a pair of protrusions. It is to be understood that two t slots may be formed, and the lateral web is positioned at the base of the walls, thereby V C C 30 forming two protrusions, the lateral web can equally well be removed on cutting.

The integrally formed fittinZ is then cut longitudinally in the direction of air flow to form the longitudinal slit, between opening of the tubular portions of the fitting, and through apices between adjacent sides of adjacent tubular portions.

Other options for forming the branch fitting include vacuum forming, or injection moulding, in which case the hal-ves can be formed separately, without a cutting step.

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i ie ti 11 These however at present have the disadvantage of a higher cost. An alternative method of forming is by rotor (or spin) moulding. Where spin moulding is used, preferably the branch fitting is formed complete and then cut as described above.

Turning now to the fifth and sixth embodiments of the invention it can be seen that the two parts (15, 16) of the branch fitting are moulded in one piece, except that in contrast to the earlier described embodiments, the originally moulded piece is made somewhat oversize in cross sectional diameter. The originally moulded piece is then cut to form the longitudinal split, such as by a suitable saw. Edges (60, 61) of the two parts (16, 15) bordering the longitudinal split, however, are not p' ced to meet in the middle but rather form a circumferential overlap. The nature of the overlap .'-.litates fastening.

The fastener (20) such as a self tapping screw can simply be appl. )m the ouide of the fittinr.

The circumferential overlap need not extend the entire length of the longitudinal split, q and thus there may not be a lateral overlap in the central portion of the branch fitting. Instead there may simply be aoutting flanges formed upwardly such as are shown in figure 14 and being similar tn that shown in Figure 2 A fastener (20) such as a pop rivet can be passed through the two adjacent flanges (18) to hold them together.

Preferably however the overlap is along the entire length of the longitudinal split (17), such as shown in the first embodiment. The apices each will be constructed as shown in Figures 2 and 4, whereby the overlap is the same degree along the entire length of the longitudinal split. The protrusion in the apices of the branch fitting each include an upright portion (62, 63) and an overlapping part (64, 65) extending away from a respective upright portion on each of a respective part of the branch fitting.

The extent of overlap is defined by the internal surface of the upright portion (62) i ,'because the overlapping portion (65) bears thereagainst, and additionally a stop (67) is 30 provided adjacenz the edge (61) of the longitudinal split on part (15) which limits the extent of overlap by edge (60) of the longitudinal split on part (16).

i The free end of the overlapping part (65) is supported against pressure exerted by fastener (20) as a result of the formation of internal ridge (66).

The manufacture, of the branch fitting is very similar as in the embodiments described earlier. The branch fitting is moulded as one piece, as indicated above with a slightly 7,V 12 oversized cross-sectional diameter. In the fifth embodiment the fitting is cut by a single cut to form each of the longitudinal splits. In the sixth embodiment a further cutting will be required to form the flanges.

Tlese halves may then be transported as required. In assembling the halves to form a branch fitting, the halves are held together, and initially the apices are joined together each by a single fastener. The tubular portions are then each individually positioned, with fasteners put into place through the overlap. The branch fitting is then ready for use.

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Claims (21)

1. branch fitting for an air conditioning duct, the branch fittin- comprising a central portion, and at least three air passageway apertures leading away from the central portion, said at least three apertures including an inlet aperture and at least two outlet apertures, and thereby including at least three corresponding inter-apertural regions between adjacent sides of adjacent apertures, the branch fitting and each aperture is split longitudinally in the direction of airflow to form two parts which two parts can be nested within the other, and fastening means fastening together the two parfs at each of the inter-apertural regions.

2. A branch fitting as in claim I wherein at least three tubular portions extend from the central portion, the three tubular portions including a tubular inlet and at least two tubular outlets, each tubular portion having at a free end a respective one of said at least three aperture, said inter-apertural regions including parts of said tubular portion and apices between adjacent tubular portions.

3. A branch fitting as in either claim 1 or claim 2 wherein at least one pair of adjacent protrusions are formed at each of the inter-apertural region, a first of the pair being formed on a first of the parts, and a second being formed on a second of the parts, the fastening means fastening together the at least one pair of protrusions for each of the inter-apertural regions to thereby join the two parts together.

4. A branch fitting as in claim 3 wherein the protrusions are positioned so that when they are held together the two parts are held against each other directly. S 30

5. A branch fitting as in either claim 3 or 4 wherein the protrusions are external of the branch fitting.

6. A branch fitting as in any one of claims 3 to 5 wherein the fastening means is a sprung metal clip, with two legs oppositely sprung with respect to one another so that when clipped over one of said at least one pair of adjacent protrusions the parts are held together by the clip. ,f *p rr 14

7. A branch fitting as in any one of claims 3, 4 or 5 wherein the protrusions are lugs, through which the fastening means can pass.

8. A branch fitting as in any of the preceding claims wherein the two parts of the branch fitting include a circumferential overlap at the longitudinal split whereby a fastener can be passed radially through the overlap to secure the two parts together.

9. A branch fitting as in claim 8 including a location means on one or both of the parts, to limit the extent of overlap of the two parts.

A branch fitting as in either claim 8 or 9 when read through claim 2, wherein the overlap is limited to the tubular portions of the branch fitting, with no circumferential overlap being provided at the apices of the branch fitting.

11. A branch fitting as in any one of the preceding claims wherein the two parts are formed as approximately equal halves of the branch fitting so that more than two parts may be nested together.

12. A branch fitting as in any one of claims 2 or claims 3 to I when read S 20 through claim 2 wherein the fastening means fastens only at the apices.

13. A part of a branch fitting being one of said parts of any one of the preceding claims. t I 25

14. A method of forming a branched fitting for an air conditioning duct, the branch fitting comprising a central portion and at least three air passageway apertures each aperture leading away from the branch fitting, said at least including at least three corresponding inter-apertural regions-between adjacent sides of adjacent apertures, said method including the step of blow moulding or rotor moulding said branch fitting, depressions being formed in a mould used ro as to form a protrusion in each of said inter-apertural regions, which protrusion can be split after the step of blow moulding to form two protrusions for adjacent location on assembly, i i said method further including the step of splitting the branch fitting and each of the apertures in the direction of airflow to form two parts which can be nested within the other the step of splitting including the splitting of the protrusion to form two adjacent protrusions.

The method as in claim 14 wherein the protrusions includes separate upright plastics portions, that are separated during the splitting process, and these upright plastics portions may be joined at an outer extremity by a further web of plastics formed during the blow moulding step, which web is split during the step of splitting.

16. The method of claim 15 wherein the further web is substantially removed during the step of splitting.

17. A method as in any one of claims 14 to 16 wherein the protrusions have a depth greater than their widths.

18. A method as in any of claims 14 to 17 wherein the two parts of the branch fitting include a circumferential overlap at the longitudinal split whercby a fastener can 20 be passed through the overlap to secure the two parts together.

19. A method as in claim 18 wherein there is provided a location means on one or both of the parts, to limit the extent of overlap of the two parts.

20. A method as in either claim 18 or 19 wherein the overlap is limited to the tubular portions of the branch fitting, with no circumferential overlap being provided at i the apices of the branch fitting. 44

,21. A method as in any one of claims 14 to 20 wherein at least three tubular S 30 portions extend from thp entral portion, the three tubular shaped portions including a tubular shaped inlet and at least two tubular shaped outlets, each tubular portion having IT the use of space. Furthermore the cutting of blow moulded iterns in half is onc that requires some precision because of the length of the split. IT 16 at a free end a respective one of said at least three aperture leading away from the branch fitting. A mould for the method defined in any one of claims 14 to 21. Dated this 5th day of June 1996 RGILYALRE PTY LTDF By their Patent Attorneys, A. P. T. Patent and Trade Mark Attorneys C lees.. C C* C .9 90 C CO C SC. I OC*p C C CC 6' 0* C 00CC C 'CCC 0* C C CC. C CC.. C CCC. t IT 7- The branch fitting may take a number of forms and at the inter-apertural regions take on a considerable range of shapes, some include more acute or complex shapes and yet ,r 17 ABSTRACT A branch fitting for an air conditioning duct which consists of a central portion, and having at least three tubular portions extending from the central portion. The tubular portions including an inlet and at least two outlets. At least three apices are accordingly defined between adjacent sides of adjacent tubular portions. The branch fitting is split and the split so formed extends longitudinally in the direction of airflow to split also each of the tubular portions. The two parts of the fitting on either side of the split can be nested one within the other. A least one pair of adjacent protrusions is preferably formed at each of the apices a first of the pair of protrusions being formed on a first of the parts, and a second being formed on a second of the parts. A fastener is used to fasten together the at least one pair of protrusions for each of the apices to thereby joining the two parts together. Sr. I I iS I CS'S rcS' 4t J~ 1i i a k