AU8514898A - Air diverter blade and air diverter assembly - Google Patents

Description

P/0010 1 Regulation 3.2

AUSTRAHJA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

TO BE COMPLETED BY APPLICANT Name of Applicant: Actual Inventor: Address for Service: NORDIN ENGINEERED AIR TECHNOLOGIES PTY LTD VICTOR JOHN SMITH A.P.T. Patent and Trade Mark Attorneys GPO Box 772, Adtlaide, SA 5001 -Invention Title: AIR DIVERTER BLADE AND AN AIR DIVERTER ASSEMBLY 0 4, Details of Associated Provisional Application No.

P09551 dated 30th. September 199.7 The following sta tement is a full description of this invention, including the best method of perforining it known to usdiverter blade.

BACKGROUND OF THE INVENTION Air diverter assemblies are a common component of air conditioning distribution systems.

These are frequently positioned either at outlets of air conditioning ducting systems in ceilings, or alternatively through wall panels.

Air diverter assemblies usually comprise a frame, which accommodates one or more sets of spaced apart and parallel air diverter blades. The blades can be either fixed in position or may be rotated, depending on the arrangement, independently of each other but Sincreasingly now in concert with each other to divert air in the desired direction. The blades of diverters within ceilings generally have an arcuate cross section, so that 15 depending on their disposition air is thrown to a greater or lesser extent laterally of the duct leading to the diverter so that air is thrown a greater or lesser extent along the ceiling. On S" the other hand blades of diverter assemblies that direct air from wall or other vertical S. surfaces have blades of a shape that might be better described as having an airfoil shape.

The air foil shape is defined between two opposed generally arcuate surfaces with opposed radii, and the opposed surfaces however may be of compound curves. Such airfoil blades will have a tendency to have a greater cross sectional dimension as a result.

The component blades are manufactured in a number of ways, those for ceilings tend to be made by injection moulding of plastics, with the entire set of blades formed to be fixed 25 within a subframe, or whereby each blade is formed independently with appropriate shapes for connection with apertures within usually a subframe for rotatable connection *therewith.

Those air diverter blades for walls are presently generally made of metal, typically aluminium, and are formed either by extrusion, or by bending lengths of aluminium into shape. Typically end fittings are made separately and fitted to the ends of the aluminium S: lengths, which are then slotted into a frame, so that the blade can be rotated with the end fitting.

35 A problem especially with the latter is that the manufacture involves considerable manual S input, and stocks offixed length material must be at hand. Additionally the assembly is: 'somewhat complex requiring considerable manual handling. Plastics has not been a material of choice largely because plastics has a tendency to be deformed, either as a result 3 the blades. With diverter assemblies positioned on walls the appearance is f greater importance because these diverter assemblies are far more apparent to occupants than assemblies situated on ceilings.

The plastics diverter assemblies used in ceilings are typically made by plastics injection moulding methods, with relatively complex shapes being formed within one or more injection moulds. The cost of making injection moulding dies is very high whereas other forming methods such as extrusion moulding require far less expensive dies and the process can be undertaken in a far more economic fashion.

A difficulty with extrusion moulding is to have effective connection of the component parts. There have been a number of suggestions for the use of extruded parts for various fan or propeller blade components, such as in Platt et. al. in US patent specification S 15 2412908, Glucksman in US patent specification 3551070 and in Atarashi et. al. in US S: specification 4971521. None of these however relates to a diverter blade as such and the 'first two are rather rigid blades and the latter is a composite blade, and none are configured for rotation about a longitudinal axis of the blade.

i 20 US patent specification 4103601 to Dayus, addresses the problem of keeping a stock of a Srange of blade lengths of the type used in wall diverter assemblies. The blades are formed Sof aluminium sheet material of which stocks of indefinite length are kept, and the stocks are first cut to size and then formed into blades. Some.embodiments use a pin to fasten the blades to end frame members. The disadvantages of the disclosure are that the method uses aluminium which is a relatively expensive commodity, and the method also uses a relatively imprecise forming process which additionally results in a join that exacerbates -4 turbulence and often a longitudinal hump to accommodate the pin further exacerbates turbulence.

OBJECT OF THE INVENTION obviates or reduces any one or more of the above identified problems by the use of an extruded plastics blade.

S- 4 In a firstaspect the invention could be said to reside in an extruded plastics diverter blade stock, said stock including, an internal pin capturing channel defined within a pin channel wall formed in the blade stock, said pin channel wall being at least in part resiliently expandable so as to provide for an interference fit with a respective pin.

In a second aspect the invention could be said to reside.in an extruded plastics diverter blade stock, said stock including, two opposed and spaced apart external blade walls, an internal pin capturing channel defined within a pin channel wall formed throughout the length of the blade stock, at least one transverse web extending between the two external blade walls, at least part of said transverse web defiring a part of said pin channel wall said pin channel wall being at least in part resiliently expandable so as to provide for an interference fit with a respective pin.

The two external blade walls may be arcuate in cross section and joined longitudinally to form a leading portion and a lagging portion. The internal pin capturing channel may be formed throughout the length of the blade stock.

In one form the two external blade walls are thin relative to the width of the blade stock in cross section, the blade stock being substantially void internally apart from the transverse web or webs and the internal pin capturing channel, an external surface of the blade being defined by said blade walls. The thinness of the external walls is desirable to accommodate temperature differences so that the time lag between contact with heated air on the outside surface of the outer wall to the time to have even heat throughout the outer wall is minimal, to thereby avoid undue warping of the outer wall and hence the blade .vwhen so formed.

In one form the blade walls aie uniformly thin over the entire surface of the blade, including the leading and the lagging edges, although certain embodiments will have tapered leading andor lagging edges where the wall thickness taken from the external surface to an internal void is considerably greater than the wall thickness elsewhere. S1-

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In preference the external blade walls are between 0.7 and 1.5 mm in thickness and more preferably between 0.9 mm and 1.2 mm in thickness.

Preferably there is only a single pin capturing channel, a blade formed from the blade stock being supported by a single pin at either end of the blade when in place. It is understood however, it may be desirable to have a single pin for rotation which is forked and has a number of blade engaging tines, however in specific embodiments of this invention a single channel permits correction of certain distortions in the blade.

In preference also outer surfaces of the blade provide an aerodynamically smooth surface so as not to exacerbate turbulence of air passing thereover, which may be a simple arcuate cross sectional shape, apart from the leading and lagging portions of the blade.

In one form two transverse webs are provided, each spaced from one another. Preferably each of the two transverse webs are positioned in a respective plane and the pin capturing channel is defined by the internal surfaces of the external blade walls and the two transverse webs, which transverse webs may be positioned parallel one with respect to the other. This latter configuration gives a pin capturing channel substantially rectangular or 20 square in cross section, but is preferably square in cross section. When used together with a round pin, this gives four lines of contact between the pin and the wall defining the pin capturing channel. It is found that such non-continuous circumferential contact enhances the interference fit between the pin and the blade. It will be recognised however that the transverse webs may be positioned differently so as to provide an irregular internal surface for the pin capturing channel, which might take the form of a multifaceted cross sectional channel which may have three or more facets. The precise shapes of the pin and the pin capturing channel can take many forms if desired, but preferably there is a non-continuous contact between the pin and the pin channel wall.

Preferably the pin channel extends over substantially all of the cross section of the blade stock so that in use a respective pin contacts the internal surface of both external walls.

In a third aspect the invention could be said to reside in an air diverter including, a frame with two end frame members with a plurality of spaced apart apertures therethrough, a plurality of spaced apart plastics diverter blades, said diverter blades formed from diverter blade stock being any of those defined or described herein, Yt 1 ij-/

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t i 6 a respective pin for each end of the diverter blade said pin including a first end frame member engaging portion, and an elongate blade engaging portion, said blade engaging portion shaped for interference fit within said pin capturing channel.

Preferably there is a frictional fit between the two end frame members and each of the pins, sufficiently to permit rotation, but also to allow for maintenance of the position of each of the blades.

In one form the blade engaging portion is split longitudinally so as to facilitate fitting of the blade engaging portion into the pin capturing channel of the blade.

Preferably the pin includes a groove to locate the pin within a respective aperture in said end frame member, the pin is preferably press fitted into the aperture. Thus the aperture may be opened to an edge of the frame member, and the pins may be fitted firstly to the 15 frame member and then press fitted upwardly into the apertures. Such an aperture is "i disclosed in Australian patent specification 647157. Alternatively the groove is formed between an expanded end of the pin, and an internal expanded portion, said pin being split longitudinally and past the internal expanded portion so that the pin can radially compress to allow for passage through the aperture and subsequent snap expansion to maintain the 20 pin in position.

In one form of the invention the blade stock is made such that the two external blade walls are thin relative to the width of the blade stock in cross section, the blade being substantially void internally with an external surface of the blade being defined by said blade walls, and there being two transverse webs, each spaced apart from one another, the e. pin capturing channel being defined by internal surfaces of the external blade walls and the two transverse web, the pin capturing channel more preferably shaped to contact both of the internal surfaces of the external blade walls and surfaces of the transverse webs so that the pins can be made of a length to assist correction of some forms of warp that might be extant in the extruded blades.

The length of the pins is such that they give sufficient grip to allow correction for a I warping effect, the thinness of the walls also permitting such correction. It is found that where the pins are about 1 cm or longer there is sufficient grip that warping can be corrected.

Sin a fourth aspect the invention could be said to reside in a method of assembling an air Sdiverter, including the step of cutting an extruded plastics diverter blade stock to length to form a plurality of plastics diverter blades, aligning the plurality of blades with apertures of two end frame members each at a respective end of the plurality of blades, inserting a pin through each respectively aligned aperture to retain the plurality of blades on said two end frame members, said plastics diverter blade stock including two opposed external blade surfaces, an internal pin capturing channel defined within a pin channel wall formed throughout the length of the blade stock.

It will be understood that blade stock used in this fourth embodiment of the invention also includes blade stocks that are described or defined in this specification.

The method might also include the step of straightening the warp that any of the blades j] might have following the step of inserting the pins.

DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION.

*For a better understanding, the invention will now be described with reference to one embodiment with reference to drawings in which S~ Figure 1 is shows a cross sectional view through two end frame members and a .20 longitudinal view of a blade positioned within the frame members, Figure 2 is a cross sectional view orthogonal to that of figure 1 showing a cross section view through blades, and side frame members, 25 Figure 3 is a close up cross sectional view of the manner in which the blade is i. connected to the end frame members, and Figure 4 is an end view of a blade.

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 i and/or exaggerated for the purposes of clarity of illustration.

The illustrated embodiment is an air diverter assembly comprising of a plurality of air "-Vif 'diverter blades and a square frame comprising end frame members 3) and side i 1i :frame members the diverter blades are held in place by respective pins -i The blades are made from a plastics such as a polyethylene by extrusion through a suitable die. The blades are formed by two opposed and spaced apart external blade walls 8) which define respectively, on their outside, two external blade surfaces 10). The two external blade walls are arcuate in cross section and are joined longitudinally to form a leading portion, (11) and a lagging portion As can be seen the external surface of the blade assumes what can be called an airfoil shape with the arcuately shaped external blade walls being opposed to one another. It can also be seen that all external surfaces are smooth with no particular interruptions to reduce the aerodynamic efficiency of the blade, and consequently that any interference with the flow of air is minimised, and additionally that the tendency of the blades to create noise is also minimised.

The blade also has two transverse webs (13, 14) which extend between the two opposed external blade walls 8) generally centrally of the blade, where the external blade walls are at a greatest distance apart. These transverse webs have two functions in the present invention. One function is to maintain the structural integrity of the blade by maintaining the two opposed external blade walls in a very stable position. A second function is to S""define, in part, a pin capturing channel j 20 It can be seen that the blade is formed so that internally the blade is substantially void, apart from the transverse webs. Additionally it can be seen that the opposed blade walls, the leading and lagging portions and the transverse webs are formed so as to be thin. In the present embodiment all of the above are about 1 mm in thickness, which includes the leading and lagging portions. It is found that distortions due to differential heating of the blades are kept to a minimum, whereas where thicker plastics were to be used there would be a substantial time.delay in heating the thickness of the walls, that is simply not a difficulty with thin walls. Additionally the thin walls have advantages in terms of assembling the diverter assembly and correction of certain defects that might arise in nrming of these walls, which will be discussed in greater detail below.

-li It can be seen that the transverse webs are spaced apart so that the pin capturing channel a i is approximately square in cross section. The pin capturing channel is defined within Sa pin channel wall which are formed by the transverse walls (13, 14) and central portions (21, 22) of the opposed external blade walls, each of which, by reason of its thinness is resiliently expandable. The cross sectional dimension of the pin capturing channel is such that a distance between opposed parts of the pin channel wall are undersized in relation to a cross sectional dimension of a blade engaging portion (23) of the pin The pin has a circular cross sectional dimension so that there is a non-continuous contact between the pin i and the pin channel wall. The oversized nature of the fit results in some expansion of four portions of the pin channel wall where the blade engaging portion of the pin contacts the r ipin channel wall. These four portions extend longitudinally and may be considered as four Slines. This ca n best be seen in Figure 3 where expansion of the transverse webs can be seen in a somewhat exaggerated fashion. The result of this expansion is that the pin is retained within the pin capturing channel with an enhanced interference fit. The interference fit is such that under operating conditions, there is no relative rotation of the pin with respect to the blade.

The blades are formed by extrusion moulding, so that a blade stock is formed in lengths.

The blade stock is then guillotined into lengths appropriate for the particular sized diverter assembly that is to be made. The thinness of the external blade walls, and the g reinforcement afforded by the transverse webs facilitates the accurate cutting process without undue deformation of the blade. It will be appreciated that any set length can readily be formed, with no particular post cutting modification required to the blade itself.

i Each end frame member is formed of a thicker plastics web, and has a plurality of apertures formed therethrough to accommodate a respective pin for rotation whilst still maintaining some resistance to movement. As a result the position of each blade can be maintained during operation without a change in direction occasioned by the force of conditioned air passing through the diverter assembly.

Each pin comprises at a first end a frame engaging portion comprising a first expanded end and a groove (31) with a tapered portion and the pin is split longitudinally so *25 that it can be compressed radially. The blade engaging portion of the pin is passed ,M through the aperture in the end frame member, the tapered portion of the pin is radially compressed to pass through the aperture, and immediately it has passed through the aperture it is expanded again to snap fit through the aperture. In an alternative the end frame member is formed in the manner as disclosed in Australian patent specification 647157, whereby the pin can be snap fitted into the frame member radially. The latter is in -J some ways preferred because the interference fit into the pin capturing channel is easier to accurately achieve.

Oi Once the blades are fitted, there are at times some irregularities such as warps in the formation of the blades. The blade can be rotated manually with respect to its two pins so as to Straighten out warps in the blades. It is found that this is possible where the pin extends somewhat into the blade. Thus in the illustrated embodiment where the pin enters ii w!t .L^X n!, I cm into the pin capturing channel it is found that some degree of straightening can be achieved.

"Various features of the invention have been particularly shown and described in connection with the exemplified embodiment of the invention, however, it must be understood that these particular arrangements merely illustrate and that the invention is not limited thereto and can include various modifications falling within the spirit and scope of the invention.

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Claims (22)

1. An extruded plastics diverter blade stock, said stock including, an internal pin capturing channel defined within a pin channel wall formed in the blade stock, said pin channel wall being at least in part resiliently expandable so as to provide for an interference fit with a respective pin.

2. An extruded plastics diverter blade stock according to claim 1 wherein the internal pin capturing channel is formed throughout the length of the blade stock.

3. An extruded plastics diverter blade stock according to claim 2 wherein the stock Sincludes two opposed and spaced apart external blade walls and at least one transverse web h 15 extending between the two external blade walls. I Is

4. An extruded plastics diverter blade stock according to claim 3 wherein the two external blade walls are arcuate in cross section and are joined longitudinally to form a leading portion and a lagging portion. 20 An extruded plastics diverter blade stock according to claim 4 wherein the external surface of the external blade walls provides a smooth surface so as not to exacerbate Sturbulence of air passing thereover.

6. An extruded plastics diverter blade stock according to claim 5 wherein the blade stock is substantially void apart from the transverse web and the internal pin capturing channel. .j .7 An extruded plastics diverter blade stock according to one of the preceding claims S 30 wherein the external blade walls are between 0.7 and 1.5 mm in thickness. S- i An extruded plastics diverter blade stock according to laim7 wherein the external blade walls are mm in thickness. :s 35 9. An extruded plastics divereblade stock according to claim-8 wherein two S transversewebs are provided each s frori one another, each of the two transverse webs being tiod in a respective pane and the pin captu channel being defined b WringI -rii i~ 1- transverse webs, which ic other. the internal surfaces of the external blade walls and the two transverse webs are positioned parallel one with respect to th An extruded plastics diverter blade stock according to claim 9 wherein there is a non-continuous contact between the pin and the internal surfaces of the external blade walls and the two transverse webs when the pin is inserted into the pin capturing channel.

11. An extruded plastics diverter blade stock according to claim 10 wherein the pin capturing channel is squarein cross section and the pin is round and when the pin is inserted into the pin capturing channel it fits such that there are four lines of contact between the pin and the internal surfaces of the external blade walls and the two transverse webs.

12. An extruded plastics diverter blade stock according to claim 11 wherein the transverse webs are 1 mm in thickness.

13. An extruded plastics diverter blade stock according to one of the preceding claims wherein the blade stock is made from a polyethylene by extrusion. 20 14. An extruded plastics diverter blade stock according to claim 13 wherein the blade stock is formed in lengths.

15. An air diverter including, "a frame with two end frame members with a plurality of spaced apart apertures 25 therethrough, S a plurality of extruded plastics diverter blades formed from the blade stock Saccording to any one of the preceding claims, a respective pin for each end of the diverter blade said pin including a first end S:-frame member engaging portion, and an elongate blade engaging portion, said blade 30 engaging portion shaped for interference fit within said pin capturing channel.

16. An air diverter according to claim 15 wherein theblade engaging portion is split longitudinally so as to facilitate fitting of the blade engaging portion into the pin capturing channel of the blade.

17. Anair diverter according to caim 16 wherein ach of the end frame members is formed ofa plastics weband has a plurality of apertures formed therethrough to accommodateth frame member enaging portion of the pin .1 .1" j -l 13

18. An air diverter according to claim 17 wherein there is a frictional fit between the two end frame members and each of the pins, said frictional fit sufficient to permit rotation of the pins and also to allow for maintenance of the position of each of the blades.

19. An air diverter according to claim 18 wherein the frame member engaging portion includes a groove to locate the pin within a respective aperture in said end frame member and the pin is preferably press fitted into the aperture.

20. An air diverter according to claim 19 wherein the groove is formed between an expanded end of the pin and an internal expanded portion, said pin being split longitudinally past the internal expanded portion so that the pin can be compressed radially to allow for passage through the aperture and subsequent snap expansion to maintain the I pin in position. 1 1 5 21. An air diverter according to clqim 20 wherein the internal expanded portion is tapered radially inward toward the blade engaging portion.

22. An air diverter according to claim 19 wherein the aperture is opened to an edge of the end frame member and the pin may be press fitted radially into the aperture.

23. An air diverter according to one of claims 21 or 22 where! I the length of the pins is such that they give sufficient grip of the blade to allow correction for warping of the blade. 9 25 24. An air diverter according to claim 23 wherein the blade engaging portion extends at least 1 cm into the pin capturing channel.:

25. An air diverter according to one of claims 15 to 24 wherein the blades are made from a polyethylene by extrusion through a suitable die. 4:

26. A method of assembling an air diverter, including the steps of, S:cutting an extruded plastics diverter blade stock to length to form a plurality of plastics diverter blades, aligning the plurality of blades with apertures of two end frame members each at a 35 respective end of the plurality of blades, S inserting a pin through each respectively aligned aperture to retain the plurality of blades on said two end frame members, 14 said plastics diverter blade stock including two opposed external blade surfaces, an internal pin capturing channel defined within a pin channel wall formed throughout the length of the blade stock.

27. A method of assembling an air diverter according to claim 26 wherein the blade stock includes blade stocks according to one of claims 1 to 14.

28. A method of assembling an air diverter according to claim 27 wherein the method includes the step of straightening the warp that any of the blades might have following the step of inserting the pins.

29. An extruded plastics diverter blade stock as hereinbefore described with reference to the accompanying drawings.

30. An air diverter as hereinbefore described with reference to the accompanying I drawings. S 31. A method of assembling the air diverter as hereinbefore described with reference to the accompanying drawings. Dated this 15th day of September 1998 S 25 NORDIN ENGINEERED AIR TECHNOLOGIES PTY LTD By their Patent Attorneys, A. P. T. Patent and Trade Mark Attorneys 'K