AU763787B2 - Methods of and apparatus for forming ducting - Google Patents

Description

lJ,3 1 "METHODS OF AND APPARATUS FOR FORMING DUCTING" This invention relates to methods of and apparatus for forming ducting.

Ducting for air conditioning is typically formed in rectangular hollow sections from sheet metal. These duct sections are formed with peripheral end flanges through which they are joined together on-site in end abutting relationship for forming continuous ducting for conditioned air.

.:*Traditionally such ducts are formed off-site and transported to the site for installation. This often results in damage to the relatively flimsy ducts and especially the protruding end flanges. The difficulty of transporting such ducting has been exacerbated by recent developments which provide preformed end flanges on the ducts which are utilised to join the ducts together on site.

The development of ducting with preformed end flanges, and typically formed from a single sheet of material, has also resulted in the provision of part-formed corner seams along the longitudinal edges of the sheet which have to be manually joined together. Such seams are known in the industry as Pittsburg seams. The seam between these longitudinal edges is formed by mating the male and female formations and subsequently bending down a protruding portion of the female formation over the male formation engaged therewith so as to lock the sheet edges together. This a very noisy operation such that the formation of such seams on-site is often impractical.

The apparatus used to form such ducting is relatively large because of the multistage nature of the forming process. This necessitates that such apparatus be installed in a factory. The consequent transport costs and the associated difficulties are thus inevitable. Furthermore the existing forming apparatus operates on sheet blanks cut from a coil of sheet material.

2 In use, such forming apparatus has to notch the sheet blank at ends of fold lines prior to forming the end flanges and the complementary longitudinal edge formations for forming the corner seam or seams. As a result when the end flanges are formed each terminates short of the adjacent flange and corner brackets are utilised to bridge the corner gaps. Such an arrangement is illustrated in US patent No. 5,342,100.

The length of the formed duct is determined by the width of the feedstock while the transverse dimensions are determined by the length of the sheet blank which may be handled by the forming apparatus. This provides a duct size limitation lo which may be formed on most machines.

S: This invention aims to provide methods of and apparatus for forming ducting which will alleviate at least one of the above disadvantages.

For simplicity the invention will be described and illustrated hereinafter with particular reference to the formation of the end flanges and notches along one side of the duct. However it is to be understood that the apparatus or methods described hereinafter with reference to one side may be applied simultaneously to the opposite side as most ducting will be formed with joining end flanges about both ends.

In one aspect this invention resides in a method of forming a duct, including:forming a sheet blank with separated end flanges along duct panel edges which are utilised to join the formed duct with an adjacent duct; terminating the end flanges adjacent the free longitudinal edges of the blank in widely spaced relationship with the free longitudinal edges such that the arm of a seaming machine may pass therebetween to enable the free edges to form a corner seam; 3 folding the blank about longitudinal fold lines extending between separations in the end flanges; joining the free longitudinal edges of the blank or of adjacent blanks by feeding them through a seaming machine; extending the end flanges adjacent the formed longitudinal seam with a corner joiner having flange extenders and a longitudinal protrusion extending from at least one of the flange extenders, and securing the longitudinal protrusion of the corner joiner to the adjacent duct panel.

The flange extenders may be connected to the end flanges to be extended by S:any suitable method such as by sliding captively into one or both sides of returned end flanges or by screwing or riveting or the like. The longitudinal protrusion may be connected to the panel by screwing or riveting or it may include a snap-in protrusion engageable with a recess formed in the longitudinal panel.

e. 15 Suitably the corner joiner is also formed with a bolting aperture at the junction of the respective flange extenders through which the corner joiners of abutting end flanges may be bolted together. Suitably the bolting aperture is slotted. Alternatively the flanges and corner joiners could be clipped together.

Suitably the blank has four or more separated end flanges at each end and it is folded up into a wrap around form for joining the free longitudinal edges together.

A typical machine suitable for this purpose is a RASS machine. These machines are utilised to form seams between edges of plain or unflanged panels. Alternatively the blank could be formed in L sections to be joined together to form a duct.

Preferably notching to form the separation of the flanges is carried out after formation of a continuous flange. The notching may be carried out in a single operation or progressively as required for folding so that the distance between folds is not defined by a fixed or set length. This enables the formed flange to be notched just upstream of the folding arrangement at any desired spacing from the previous notching and fold line.

In another aspect this invention resides in a corner joiner for a duct and including:a corner portion; a pair of flanges integral with and extending from the corner portion for forming end flanges about the corner of adjoining panel ends of a duct; a longitudinal protrusion extending from at least one of the flange extenders, and securing means for securing the longitudinal protrusion to an adjacent panel of the duct.

The securing means may be apertures for screws or rivets or simply a land for receiving a self drilling screw. Alternatively the securing means may be a return or rib extending parallel to the flanges and adapted for snap-in engagement with a recess formed in the adjoining panel. Suitably the corner portion is also formed with a bolting aperture through which the corner joiner may be bolted to another member.

In yet another aspect this invention resides broadly in forming apparatus for forming duct blanks, including:a forming station at which end flanges are formed along opposing edges of a feedstock or sheet blank; notching means for notching the formed end flanges whereby they are separated into a series of flanges along the feedstock, and feed means for selectively feeding the feedstock or blank through and beyond the forming station whereafter the formed continuous end flanges are separated by the notching means into separate flanges each associated with a respective side panel of the duct to be formed.

Suitably the forming station is a rollform station at which the end flanges are formed as the blank is fed therethrough. Preferably the notching station includes an :,:":external die which may be positioned in close proximal or abutting relationship about the outer face of the formed end flange and a conforming punch which feeds upwardly and outwardly through the die to effect the notch. For a flange having a returned outer edge it is also preferred that the die include a inner abutment which extends across the inner face of the return to support it for punching operations.

The notching means may form a simple narrow rectangular notch such as when a Pittsburg seam is used to manually join the duct edges together.

o,•°o Alternatively the notching means may form a simple narrow rectangular notch for separating the flanges at fold lines as well as a broad notch for terminating the flange adjacent the longitudinal edge to be joined in a relatively wide spaced relationship therewith to enable entry of a seaming machine between flanges adjacent the free edges of the formed duct blank.

The blank may be a precut length but preferably the blank is a continuation of a feedstock sheet and is severed therefrom by severing means after the notching process has been effected. Suitably the severing means passes between formed broad notches shaped to form leading and trailing ends of adjacent duct blanks.

The forming apparatus may be utilised to form and fold a blank of the type defined above adapted for closing by the use of a machine seamer or it may be used to form a blank with complementary seam formations along the longitudinal edges so that these edges can be manually joined together in conventional manner.

Preferably the forming apparatus includes a combined folding head and guillotine including a relatively narrow anvil portion providing a folding edge at one side and a cutting edge at its opposite side, a clamping bar selectively moveable toward the anvil portion to clamp the blank to be folded therebetween against the anvil portion, a folding bar pivotable about a centre substantially co-incident with the folding edge and a guillotine blade co-operable with cutting edge to sever the blank from the feedstock.

o.oo Suitably the folding bar is carried with the clamping bar to its operative folding position at which it pivots substantially co-incident with the folding edge.

It is also preferred that the anvil portion has a width in the feed direction of o less than 150mm so that wrap around sections may be formed on the folding •ooo° apparatus with a minimum section size of about 150mm and a maximum section limited by clearance space for rotating the partly folded duct about the folding edge.

If desired, the forming apparatus may include severing means and notching means upstream of the forming station for forming notches prior to forming the flanges as well as a Pittsburg seamer so that the apparatus can be used to form ducts in conventional manner.

In yet a further aspect this invention resides broadly in forming apparatus for forming duct blanks, including:notching apparatus for notching the opposed edges in the sheet blank whereby the edges are separated into a series of flanges along the sheet blank and for forming notches in end flanges formed along the sheet blank or sheet feedstock, said notching means being capable of forming a broad notch through formed end flanges; forming apparatus for forming end flanges along opposing edges of sheet feedstock or a sheet blank; seaming apparatus for preparing free longitudinal edges of the duct blank with complementary seam sections; :.:":severing apparatus for severing the sheet feedstock through corresponding gk notches formed in opposing edges of the sheet feedstock; folding means for folding the sheet blank of feedstock into the desired duct l0 shape; feed means for selectively feeding the sheet feedstock or sheet blank for forming notching seaming and folding, and S. *selection means for selectively actuating the apparatus for forming a duct blank with complementary seam sections to be joined or for forming a duct blank by severing through a broad notch to form opposed flanges which may be joined together in a Rass type seamer.

In order that the above inventions may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a typical forming apparatus according to one aspect of this invention, and wherein:- FIG. 1 is a side elevational view of the roll forming apparatus and showing 14 designated stations; FIG. 2 is a plan view of the roll forming apparatus illustrated in Fig. 1; FIG. 3 and FIG. 4 illustrate the configuration of the folding assembly at station 14; 8 FIG. 5 is a perspective view of the cutting and folding head comprising stations 12 to 14; FIG. 6 is a further perspective view of the cutting and folding head of Fig. and showing the means of actuating the folding bar at station 14; FIG. 7 is an end view showing illustrating the notching operation; FIG. 8 is a view similar to Fig. 7 but illustrating the notch operation partially ~:completed; FIG. 9 is a side view showing the notching operation for forming a relatively wide notch; FIG. 10 is a diagrammatic perspective view illustrating the notch component •forming the notch of Fig. 9; FIG. 11 illustrates a flange formed with a slot type notch and a broad type notch; FIG. 12 illustrates a duct formed by the apparatus illustrated in Figs. 1 2 FIG. 13 illustrates the duct after the longitudinal edges have been joined by a Rass seamer; FIG. 14 is a plan view of a corner joiner for joining the flanges about the seamed edge of the duct of Fig. 13; FIG. 15 is a side view of the corner joiner; FIG. 16 is an end view showing the duct with the corners of the flange joined by the joiner illustrated in Figs. 14 and 15 at the seamed corner and conventional corner joiners about the remaining corners, and FIG. 17 is a rear perspective view of a joined corner.

Referring to the drawings it will be seen that the forming apparatus 20 is adapted to form flange ducts having lengths equivalent to the width of the coil sizes 9 which in this embodiment range from 900mm to 1530mm wide. These coils 21 are supported at one end of the apparatus 20 at Station 1. The sheet is fed through the various stations to the Folding Station 14 at which folding is effected by a folding bar 22 having gaps 23 therethrough to accommodate the formed end end flanges 24, the various gaps corresponding to different width sheets.

The feedstock from the coil 21 at Station 1 passes through a guide at Station 2, through pinch rollers 39 at Station 3 for passage through straightening rolls 37 at Station 4 whereafter the straightened sheet is fed through a series of operating stations which may be optionally used if required.

Typically the next optional station, Beading Station 5 includes beading rollers 38 which form stiffening beads along the length of the feedstock which become transverse stiffening beads in the formed duct. The further optional stations are utilised for forming ducting in conventional manner and include a Slitter Station 6 which may be used to cut the feedstock into fixed lengths.

A Seamer Station 7 forms the male and female longitudinal flange formations across the sheet blank.

A Notching Station 8 is provided so that the longitudinal edges of the sheet blank can be notched prior to passing to the Roll Forming Station 9 at which the longitudinal edges are roll formed into the conventional shape to form the end flanges of the formed duct which are able to receive slide-in or snap-in corner connectors of conventional form.

Preferably however, the optional Stations 6, 7 and 8 are not utilised. Instead, continuous feedstock is fed to the Roll Forming Station 9 so that the end flanges 24 are formed from the longitudinal edges of the feedstock, including the continuous returned shape 61 of the end flanges 24, as shown in Fig. 7.

it Notching Stations 10 and 11 provided downstream of the Roll Forming Station 9 utilise notching apparatus 53 which may be selectively controlled to cut notches through the formed flanges 24 at desired positions therealong. As shown in Fig. 11, the notches which may be cut include a relatively broad notch 25 and a narrow notch or slot 26.

The slot 26 is provided to separate the formed continuous flange 24 into flange portions at either side of each formed corner whereas the broad notch 25 is formed at the position at which the blank is to be severed from the feedstock leaving protruding portions 51 and 52 which protrude beyond a trailing end flange 27 and a leading end flange 28 formed at opposite sides of the broad notch ~The notching apparatus 53 may be arranged to travel along the bed 34 0. extending from the Roll Forming Station 9 for forming notches at desired positions or it may be fixed such that the sheet feed selectively positions the feedstock for ooooi notching operations.

After notching the flanged sheet is advanced for severing at Stations 12 and folding at Station 13. The broad notch 25 is advanced to a position in alignment with the severing means 54 which severs the sheet partway through the notch 25 so as to leave the appropriate flange cutout and leading and trailing flanges 27, 28.

After the leading broad notch 25 has been formed, the feedstock sheet with the flanges 24 formed, or being formed continuously along the opposed side edges thereof, is notched at Station 11 at a suitable position to define the first corner about which the first corner fold 31 is effected. Thereafter a further notching operation is carried out to enable the continuous blank to be folded at corner position 32. This operation is repeated to enable a further corner fold to be carried out at 33, whereafter a broad notch 25 is again formed through the flanges 24 to permit the 11 partly formed sheet blank 29 to be severed and the folded duct to be removed from the apparatus 20 for closing of the adjacent free longitudinal edges5, 52.

Referring specifically to Fig. 3 and 4, it will be seen that the Cutting and Folding Stations 12, 13 includes a common fixed anvil member 40 having a cutting edge 41 at one side and a folding edge 42 formed at its opposite side. A clamping bar 43 carried by arms 46 pivoted at 44 may be urged upwardly by a hydraulic ram toward the anvil member 40 to clamp the feedstock against the underside of the folding edge 42.

The arms 46 also carry the folding bar 47 on links 48 pivoted to the arms 46 about further pivots 49 which are brought to a position substantially coincident with the folding edge 42 when the arms 46 are urged upwardly into their operative clamping position by the cylinders 45. The folding bar 47 may be pivoted by S*0 actuating rams 50 to effect upward folding of the partly formed feedstock about the edge 42.

The pivot 44 is mounted on an eccentric so that the axis of the pivot 49 relative to the folding edge 42 may be adjusted to effect either a sharp bend or a more gentle bend or to provide adjustment for different thickness feedstock material.

A further hydraulic ram 55 is connected to the lower movable guillotine blade 56 which may be urged upwardly in a shearing action against the fixed cutting edge 41. This arrangement is illustrated in a cutaway perspective view in Fig. 5 and in Fig.

6 which also illustrates the arrangement of the arms 46 and the links 48.

Figs. 7 to 10 illustrate the notching mechanism for performing the broad notches 25. Referring initially to Fig. 7 which illustrates only one edge of the sheet of the feedstock, it will be seen that the roll formed flange 60, which forms the end flanges 24, is of a shape or re-entrant configuration provided with a returned free 12 edge at 61. Typically this flange captively accommodates the flange extensions 76, 77 of a corner joiner 75 as illustrated in Figs 14 to 16. For this purpose it will be seen that the flange extensions 76, 77 are mirror images on one another about a plane passing through the axis of the joining aperture 79.

For notching purposes, a die 66 having a cutout 68 in the shape of the broad notch 24 of the required shape is brought, suitably by pivoting, into engagement of the outside face of the section flange 60, while stops 65 are engaged with the internal face of the section so as to clamp the return flange 61 therebetween at each side of the cutout o be formed.

The punch 69 is mounted for reciprocation along an inclined axis, arranged at 450 to the horizontal in this embodiment, and adapted to pass upwardly from an inside position through the folded flange for notching it to the required shaped.

During this process, the unsupported portion of the return flange 61 in the part of the l le flange removed, will be folded upward, as illustrated in Fig. 8 and moved upwardly prior to the die 66 passing through the outer wall portion 67 of the section flange Thus in order to ensure that a clean cut is performed, the die 66 has a substantially rectangular base portion 70 extending upwardly beyond the folded extent of the returned flange 61 to permit its upward passage through the cutout, as well as an upper trapezoidal section 71 which tapers upwardly and inwardly. In this embodiment the return flange 61 is approximately 10Omm deep and thus the depth of the rectangular base portion 70 is in the order of 17mm deep to provide the necessary clearance..

In use, the forming apparatus 20 may be used with the optional Stations 6, 7, 8 to form ducting in conventional manner. This results in the formation of a blank 13 having notches through the flanges which are fed in turn to a position aligned with the folding edge 42 and folded up by upward pivoting of the folded bar 47.

The open box section duct blank 29 is then fed onto a Pittsburgh seamer wherein the folded blank 29 as illustrated in Fig. 12 is formed into the seamed and flanged duct 36 as illustrated in Fig. 13.

However, it is preferred that continuous feedstock be fed through Station 9 so that the shaped edge formations are formed continuously thereon, through the notching Station 10 so that the required notches are formed. The broad notch 25 is carried to a selectively aligned position with the severing Station 12 at which the l0 feedstock is severed through the base of the notch to provide respective notches along the opposite flanged edges of the feedstock.

After the broad notch 25 has been formed, the narrow notches or slots 26 are formed through the flanges 24 at positions which will enable respective end flanges 24 to extend between corners of the duct panels 35 of any selected width. These slots 26 are formed in a similar manner as described above. However the rectangular shape is carried the full depth of the flanges 24 The notches 26 then pass into alignment with the folding apparatus enabling the duct panel 35 to be progressively folded upwardly to form a wrap around rectangular hollow duct with free longitudinal edge portions As illustrated in Fig. 12 the widely spaced end flanges 27 and 28 at each end of the duct blank 29 are associated with protruding edge portions 51, 52 which remain co-planar with the adjacent duct panels 35. The provision of the widely spaced flanges 27 and 28 formed by the broad notches 25 effected at Station 10 are provided to enable the passage of the free edge portions 51, 52 through a seaming 14 machine such as a Rass type seamer to close the seam at 58 and form the closed duct 36 as illustrated in Fig. 13.

However, these widely spaced flanges 27 and 28, as illustrated in Fig. 13, provide a weakened corner which cannot be secured effectively to adjacent duct flanges using conventional corner joiners. In order that an effective joint may be made at the weakened corner, a corner joiner 75 as illustrated in Fig. 14 and, 15 is utilised. This joiner 75 includes relatively long flange extensions 76 and 77, each of which is provided with an inner protrusion 78 which is apertured and adapted to lie S .i alongside the adjacent panel 35 of the formed duct. The joiner 75 is provided with a 0 central aperture at 79 to enable it to be bolted to adjacent corner joiners.

As illustrated in Fig. 16 and 17 the flange extensions 76 and 77 are received within the section flanges 24 each of which forms a re-entrant recess 57 which is able to capture a respective one of the flange extenders of a corner joiner either by sliding and/or clipping therein joiners into captive engagement within the re-entrant o..o 15 recesses 57. In the embodiment illustrated in Fig. 17, the re-entrant recess is formed by a slight return of the free edge portion 62 to provide a clip-in engagement of the corner joiner 75. After the flange extensions are formed the protrusions 78 may be screwed, bolted or riveted to the adjacent duct panel 74, as shown at 80 for example, to provide stability and strength to the corner joiner The apparatus 20 is suitably computer controlled so that a the required duct forms may be inputted, and including equal and unequal sides and in wrap around form with integral end joining flanges, for automatic production of the folded duct blanks for closing along a single seam by mechanical seaming apparatus. The computer control may successively control the advance of the sheet feed stock to the folding station to suit input panel widths and the notching apparatus for forming the desired notches at the junction between duct panels.

It will be seen that the forming apparatus is very compact. Thus it may be carried on a truck or trailer onto a construction site for substantially noiseless forming of the ducts required. This will reduce transport damage and will minimise delays in producing special sections which may not have been incorporated in the initial production.

It will of course be realised that whilst the above has been given by way of illustrative embodiment of the invention, all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as ids defined in the appended claims.

o o**o* *o*o*

Claims (17)

1. A method of forming a duct, including:- forming a sheet blank with separated end flanges along duct panel edges terminating the end flanges adjacent the free longitudinal edges of the blank in widely spaced relationship with the free longitudinal edges; folding the blank about longitudinal fold lines extending between separations in the end flanges; 10 joining the free longitudinal edges of the blank or of adjacent blanks by feeding them through a seaming machine; S°*extending the end flanges adjacent the formed longitudinal seam with a corner joiner having flange extenders and a longitudinal protrusion extending from at least •one of the flange extenders, and 15 securing the longitudinal protrusion of the corner joiner to the adjacent duct S• panel.

2. 'A method as claimed in claim 1 and including forming each end flange with a re-entrant recess able to capture a respective one of the flange extenders of a corner joiner, and sliding or clipping the flange extenders of the corner joiners into captive engagement within said re-entrant recesses.

3. A method as claimed in claim 1 or claim 2 and including forming the corner joiners with a joining aperture in the corner portion and the flanges as mirror images of one another about a plane passing through the axis of the joining aperture 17 whereby abutting end flanges of end connected ducts may be bolted together through aligned joining apertures in the corner joiners.

4. A method as claimed in any one of the preceding claims, wherein notching to separate end flanges is carried out after formation of a continuous flange along the longitudinal edge of a sheet blank.

A method as claimed in claim 4 including notching the formed flange upstream of the folding station and at spacings to from the desired duct panel widths.

6. A method as claimed in any one of the above claims, including providing computer control means to successively control the advance of the sheet feed stock to the folding station to suit input panel widths and to control the notching operation for forming notches at the junction between duct panels. .*t

7. Forming apparatus for forming duct blanks, including:- a forming station at which end flanges are formed along opposing edges of sheet feedstock or a sheet blank; notching means for notching the formed end flanges whereby they are .20 separated into a series of flanges along the sheet feedstock or sheet blank, and feed means for selectively feeding the sheet feedstock or sheet blank through the forming station to the notching means.

8. Forming apparatus as claimed in claim 7, wherein the forming station is a roll forming station at which the end flanges are formed as re-entrant flanges and the 18 notching station includes an external die which may be positioned in close proximal or abutting relationship about the outer face of a formed end flange and a conforming punch which feeds upwardly and outwardly through the die.

9. Forming apparatus as claimed in claim 7 or claim 8, wherein the notching station may selectively form a narrow notch or a broad notch and including a Pittsburg type seamer which may be selectively utilised to form complementary seam formations along the free longitudinal panel edges of a partly formed duct.

10. Forming apparatus as claimed in any one of claims 7 to 9 and including a folding head and guillotine.

11. Forming apparatus as claimed in claim 10, wherein the folding head and guillotine share a relatively narrow anvil portion providing a folding edge at one side and a cutting edge at its opposite side and a clamping bar which is selectively moveable toward the anvil portion to clamp the sheet blank against the anvil portion.

12. Forming apparatus as claimed in claim 11 and including a folding bar pivotable about an axis which may be selectively positioned with respect to the folding edge.

13. Forming apparatus as claimed in claim 12, wherein the folding bar is carried .:.with the clamping bar to its operative folding position. with the clamping bar to its operative folding position. 19

14. Forming apparatus as claimed in any one of claims 7 to 13, and including severing means and notching means upstream of the forming station for forming notches prior to forming the flanges.

15. Forming apparatus for forming duct blanks, including:- notching apparatus for notching the opposed edges in the sheet blank whereby the edges are separated into a series of flanges along the sheet blank and for forming notches in end flanges formed along the sheet blank or sheet feedstock, said notching means being capable of forming a broad notch through formed end flanges; forming apparatus for forming end flanges along opposing edges of sheet feedstock or a sheet blank; seaming apparatus for preparing free longitudinal edges of the duct blank with complementary seam sections; severing apparatus for severing the sheet feedstock through corresponding notches formed in opposing edges of the sheet feedstock; folding means for folding the sheet blank of feedstock into the desired duct shape; feed means for selectively feeding the sheet feedstock or sheet blank for 20 forming notching seaming and folding; and selection means for selectively actuating the apparatus for forming a duct blank with complementary seam sections to be joined or for forming a duct blank by severing through a broad notch to form opposed flanges which may be joined together in a Rass type seamer.

16. A method of forming a duct substantially as hereinbefore described and/or illustrated in any one or more of the accompanying drawings.

17. Forming apparatus for forming duct blanks substantially as hereinbefore described and/or illustrated in any one or more of the accompanying drawings. DATED THIS Sixteenth DAY OF May 2003. KAVANAGH INDUSTRIES PTY LTD By PIZZEYS PATENT TRADE MARK ATTORNEYS *o o