GB2355047A

GB2355047A - Slotted edge locator for an adjustable angle fan blade

Info

Publication number: GB2355047A
Application number: GB0101474A
Authority: GB
Inventors: Christopher Winston Lack; David Peter Fenner
Original assignee: Elta Fans Ltd
Current assignee: Elta Fans Ltd
Priority date: 1997-02-15
Filing date: 1997-02-15
Publication date: 2001-04-11
Anticipated expiration: 2017-02-15
Also published as: GB2355047B; GB0101474D0; GB2322166B; GB2322166A; GB9703163D0

Abstract

A fan with angularly adjustable blades has a slotted locator 26 for the edge of a fan blade 16 to enable the fan blade to be located in a plurality of predetermined angular positions. The locator has a flat flexible spine with a plurality of equally-spaced parallel ribs 30 extending perpendicularly from the plane of the spine to define slots 32. The ribs may have a curved aerodynamic shape. A push-fit connector for location in a co-rotating fan shroud 14 has a cylindrical boss 34 with a part spherical head 36. The locator 26 may be injection moulded from plastic such as polypropylene, so that it flexes to take up curvature of the shroud 14, or so unused ribs may be cut off. The slots may be labelled to identify for example blade angle, while the boss 34 may be offset by half a slot width (fig 6) to allow a greater range of angles, or boss at the end of the spine (fig 7).

Description

2355047 A Fan Blade Angle Locator The invention relates to a fan blade

angle locator.

In a fan having angularly adjustable blades, it can be a problem to align a blade at the desired angle and also to ensure that all of the blades are at precisely the same angle. This is particularly the case where the fan is intended to be assembled by semi-skilled labour.

According to the invention there is provided a fan blade agnle locator comprising an elongate spine, the elongate spine mounting a plurality of projections to an upperside thereof, the projections defining therebetween a series of equal width blade locating slots equally spaced along the axis of the spine, the spine including to the lower side thereof means for connection to a fan.

This simple device can be used by connecting it to a fan to reliably locate a fan blade in one of a plurality of positions corresponding to the slots defined by the locator.

As the locating slots positively locate the fan blade in one of a plurality of predetermined angular positions, it is easy to obtain the correct blade angle. The fact that the locating slots can act with the edge of a fan blade means that they can act at a significant distance from the axis of angular adjustment of the blade so that even relatively small angles of movement are well separated and readily and accurately achieved.

Preferably, the spine is flexible. In this way, the spine can be placed against hub or shroud surfaces of different curvature and can flex to accommodate them.

The projections may take any suitable form, but preferably the projections are 3) 0 ribs which may have their axes perpendicular to the longitudinal axis of spine. The spine and projections are preferably aerodynamically shaped. There will inevitably be some interference with the flow of fluid through the fan as a result of the presence of the locator, but by making the locator aerodynamically shaped this can be minimised.

For this reason, the ends of the ribs are preferably curved downwardly. The spine and pr jections are preferably greater in length and width than in height.

OJ The connection means make take any suitable form preferably being a mechanical connection which may be of the push-fit type. The connection means may thus comprise a head on a neck. The connection means may be central with respect to the spine or may be offset. In one embodiment the offset is half the width of a slot. In another embodiment the connection means is offset to at or adjacent one end of the spine.

The locator may conveniently be made of plastics material and may be a one-piece moulding.

Three embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

Figure I is a side elevation in cross-section of a fan including a locator according to the first embodiment of the invention, Figure 2 is a side elevation of the locator of the first embodiment'.

Figure 3 is an underneath plan view of the locator of figure 2:

Figure 4 is an end elevation of the locator of figure 2; Figure 5 is a detail perspective view of the fan of figure 1; Figure 6 is a side elevation of a locator of a second embodiment; and Figure 7/ is a side elevation of a locator of a third embodiment.

The fan 10 of figure I comprises a hub 12 and a shroud 14 with a plurality of angularly adjustable blades 16 extending between the hub 12 and shroud 14. Each blade 16 is connected to the hub 12 and shroud 14 by screw fastening means 18, the majority of which are not shown. The hub 12 is driven by a motor 20 on the axis of the fan. The hub 12 includes a hemispherical portion 22 from the drive shaft including the point of connection by the fastener 18 which leads into a flared part 24 which flares smoothly onwards. The shroud 14 is part spherical connection with the hub 22 and the blades 16 have part spherical tips and part spherical roots over the hemispherical part 22 of the hub 12 such that the blades 16 can be pivoted about an axis constituting a radius of the concentric spherical surfaces 14, 22 and the tip and root of the blade 16 will remain in contact with the part spherical surfaces. The blades 16 can include a twist along the axis of adjustment.

The angle of each blade 16 is fixed using a locator 26 as shown in detail in figures 2, 3 and 4. The locator 26 comprises a flat flexible spine 28 from which a plurality of parallel ribs 30 extend perpendicularly from the plane of the spine 38, the ribs 30 being parallel with their axes perpendicularly to the longitudinal axis of the spine 28. The ribs 30 are equally spaced and define equally spaced identical rectangular slots 32 between them. The width of each slot 32 is the same as the width of each rib 30. The end 38 of each rib 30 is smoothly curved downwards. A cylindrical boss 34 extends perpendicularly from and centrally of the spine 28 to the opposite side of the ribs 30 and terminates in a part spherical head 36 which is just wider than the boss _3)4.

The spine 28 is flexible and the locator 26 is preferably integrally made of plastics material and may be of an injection moulding of for example polypropylene.

The shroud 14 is made with two apertures, 40, 42. One aperture 42 receives a bolt to fasten the blade 16 to the shroud 14. The other aperture 40 receives the boss 34 of the connector which is push-fit into the shroud 14 to be retained by the head 36. The flat flexible spine 28 of the locator 26 will flex to take up the curvature of the shroud 14. The blade 16 is rotated to the desired position by locating it above the desired slot 32. Each of the slots 32 thus defines a predetermined angular position, the position of the aperture 40 being precisely predetermined with respect to the aperture 42. The bolt through the aperture 42 is then tightened to draw the edge of the blade 16 into the described slot 32. The blade edge includes a small cut-out 44 to receive the spine 28 of the locator 26 so that the blade 16 can lie in contact with the inner surface of the shroud 14. The blade is then bolted to the hub 12.

,Id=xo.ioj ssQ"oiql poonpoi jo uij L, Xq p3uojuam q pw 9Z ouids oLli puo slqi O-L 'tc, ssoq gqi jo z)p!s ioqjo z)Lll ol 9Z iol-ez)ol all jo 11-c pAN iojo2oj jjo ino iq X-ew oc qli jpuij zqj posn;)q ol si opjs ouo uo Zcjols ol-ewillnuod 3ql jj 'juowipoqLuz) lsjij oqj ui snLIJ -jjo =T41 'OuTlinz) Xq 'oldLu-exo ioj 'P;)AOUJQJ z)q knu 9- iol-cool oqj jo siird ssooxo 'uz)soqo uz);)q stq ol'our OZ op-elq QLjj oouo 'upj;)Lli q2noxql moU jiu UO jO0JJQ U73 OA-eq JJIM IOIL'Z)01 0j SV -ot7 ainliodu ui tc- ssoq oqi inoq-e 9Ziolrool qj jo uoijujoi q pjupowwooop oq uro sol',Duu;)pLlq jo o2u-ci igjuoj2 p Xe.m siql ul -tc ssoq all ol Iriluo'ou- cl si SZ ouids oqi jo o0p;) oqj i-all Ljons gZ ouids;)qljo puo all ol jznjjirg T4onuj iz)sjjo si tc ssoq all lo,,,)moq osuo siql ul -Isjlj;Dql ol mIlLuis uiOr si luoLuipoqLuo pjiqi oqj jo 9Z jolrool;qj -3q pjnos 9Z imool oLli punoi KpmT4z)iiqm TqjpAioqjo2oi poijpods )q Is= 9Z ioluool oqijo c iols z)qi;)j2ur up ougop ol -pirpomwooo-e;Dq uro 2upuds iosolo i-c solOuu;Dpplqjo o2uej j.)jp;)j' r snLI 01 0 _L -oc sq!l jq poidnooo XjsnolAoid suoilisod ap ui p;)pAoid oxe Zc- slols ot oinindu;)qj ui tE ssoq Dql jo uoijujo.1 Kq Xum siql uj -Zc jols; )uojo iliplm oqijjeLj Xq 8Z ouids;)Llljo pu) ouo spumol losjjo si tc ssoq oql jpqj idooxz) lsjij OLIJ 01 JUJIUJIS IX)A Sl JUOULITPoqtuD puoos oqi jo 9Z jolrool 3qj -Pojinboi ii oz)uoiQjo.I u.10 o1suv c opulq ipqj Llli.AA '31dLupxQ ioj pjjoqj oq au Zc slols z)ql -ojur ouius Qqj Kjospoid ve oq IIIA,\ 9 1 sopulq z)T41 jo Ilu kem siql ul -poqjiosop su ji ui o2po op-ep OT41 uollisod pur Zc- iols r io;Dl;)s IdLuis u-eo josn e pzmds put p3zis pstowd Qxe 9- joltool oqi ui Zc siols oLli pur puopisod XIospoid si 9Z iolvool z)ql jo ot oinliodu oql sV t,

Claims

Claims

I A fan blade angle locator comprising an elongate spine, the elongate spine mounting a plurality of projections to an upper side thereof, the projections defining therebetween a series of equal width blade locating slots equally spaced along the axis of the spine, the spine including to the lower side thereof means for connection to a fan.
2. A locator as claimed in claim 1, wherein the spine is flexible.
3. A locator as claimed in claim I or claim 2, wherein the projections are ribs.
4. A locator as claimed in claim 3, wherein the ribs have their axes perpendicular to the longitudinal axis of the spine.
5. A locator as claimed in any preceding claim, wherein the projections are aerodynamically shaped.
6. A locator as claimed in claim 5 when dependant on claim 3 or claim 4, wherein the ends of the projections are curved downwardly. 20
7. A locator as claimed in any preceding claim, wherein the combined element consisting of the spine and projections is greater in length and width than in height.
8. A locator as claimed in any preceding claim, wherein the connection means is 25 a mechanical connection.
9. A locator as claimed in claim 8, wherein the connection is of the pushfit type.
10. A locator as claimed in claim 9, wherein the connection means comprises a 3'0 head on a neck.

6
11. A locator as claimed in any preceding claim, wherein the connection means is central with respect to the spine.
12. A locator as claimed in any preceding claim, wherein the connection means is offset.
11.

A locator as claimed in claim 12, wherein the connection means is offset by half the width of a slot.
14. A locator as claimed in claim 122, wherein the connection means is offset to at or adjacent one end of the spine.
15. A locator as claimed in any preceding claim, wherein the locator is made of plastics material. 15
16. A locator as claimed in claim 15, wherein the locator is a one-piece moulding.
17. A locator substantially as described herein with reference to figures 1-5, 6 or 7 of the accompanying drawings. 20
18. A fan including a locator according to any preceding claim.