HK1161340A1 - Combined ceiling fan and light fitting - Google Patents

Abstract

There is provided a combined ceiling fan and light fitting (10) having blades (1 - 4) that when the ceiling fan is not in use retract and are stowed above an enclosure (12) containing a light emitting device and that when the fan is in use are extended under centrifugal force. The blades are formed in such a way as to both stow compactly above the enclosure and provide reasonable aerodynamic performance. Each blade partially overlies a neighbouring blade when in its stowed position and the blades are so formed as to permit such stacking while limiting the overall height of the assemblage of stowed blades.

Description

Combined ceiling fan and light fitting

Technical Field

The invention described herein relates to a combined light fitting and ceiling fan (combined light fitting and ceiling fan) having blades that fold compactly when the fan is not in use and move outwardly when the fan is activated. More particularly, the present invention relates to an improved fan blade for such a device.

Background

Ceiling fans have been known for a long time and are used as an inexpensive way to provide air flow in a room of a building. When compared to such alternatives as cooling and evaporative air conditioning units, the ceiling fan is simple to use and install, safe, and inexpensive to purchase and operate. They generally provide the surprising effect of alternative air conditioning, since the air flow they produce can evaporate skin perspiration with a resulting cooling effect.

It is known to combine ceiling fans and lighting fixtures because firstly it is generally necessary to provide a ceiling mounted light source and secondly it is convenient to provide a single power supply to operate the combined fan and light fixture.

Less commonly, it is also known to provide combined light fixtures and ceiling fans with some kind of folded or retracted blade arrangement. Le Velle describes three forms. Us patent 1445402 discloses a light fitting and ceiling fan in which the blades move outwardly under centrifugal force when the fan is on and are retracted by a spring when the fan is off. Us patents 1458348 and 2079942 disclose a modified form in which (unlike the form of earlier patent 1445402) the inward and outward movement of the blades is synchronised. The synchronized blade movement is important to maintain a good balance of the rotating parts of the fan. More recently, a combined light fixture and ceiling fan has been disclosed by Villella (see International patent publication WO2007/006096), and the built-in and simple synchronous arrangement of blade movement lends itself to being a lead to modern designs.

A problem in the design of combined light fixtures and ceiling fans is to provide blades that provide beneficial air moving properties when in use without the need for additional electrical power and that can be folded into a fairly compact overall form when not in use. The present invention solves this problem.

The reference to certain patents above and elsewhere in this specification is not, and is not to be taken as, an admission that anything therein forms part of the common general knowledge in the art in any location.

Summary of The Invention

For convenience and brevity, the combined ceiling fan and light fixture will be referred to as a fan/lamp in this specification.

The present invention relates to a fan/light having a plurality of fan blades that move outwardly to an operating position during fan operation and inwardly to a stowed position when fan operation is stopped. The outward movement of the fan blades may be accomplished by the action of centrifugal force as the blades are rotated about the fan axis by the motor. Retraction of the fan blades to their stowed positions may be by the action of resilient means such as one or more springs.

The blades are adapted and arranged to move air downwardly as they rotate when in their operative position and to lie within a defined radius from the fan axis when in their stowed position, for example the radius of a translucent housing of circular form (when viewed in plan view) for a light emitting device such as an incandescent lamp. Each blade may overlap at least one other blade when stored.

The preferred form and relative positioning of the vanes is disclosed and is believed to be a beneficial balance between the need to provide reasonable air movement and the need for compact storage of the vanes when not in use. These forms are characterized in particular by a certain distribution of the pitch angle, the chord length of the blade (distance measured from the front edge to the rear edge) and the dihedral angle. They are preferably airfoil-shaped cross-sections with a curvature such that the lower blade surface is concave and the upper blade surface is convex.

More specifically, the present invention provides in a first aspect a combined ceiling fan and light fitting having a plurality of fan blades, wherein:

each vane is pivotally mounted to be pivotable about an upright pivot axis of the vane between a stowed position and a deployed position;

each blade, when in its stowed position, is located within a specified radius from the axis of rotation of the upright fan and above the light fixture portion, and has an air moving portion (air moving portion) extending beyond said specified radius in the deployed position of the blade; and is

Each vane is generally elongate and arcuate when viewed in plan and extends peripherally (perpheraly) within the specified radius between its pivot axis and the tip end (tip end) of the vane in its stowed position and partially overlaps adjacent ones of the vanes in their own stowed position;

a combined ceiling fan and light fitting characterized by:

(a) each vane initially increases in height above a reference height with increasing distance along the vane from its pivot axis end so that the vane overlaps the pivot axis end of an adjacent vane in its stored position when in its stored position, an

(b) As the distance increases from the pivot axis end of the air moving portion to the apex tip of the blade, the leading edge of the air moving portion first increases in height above the reference height and then becomes downward, thereby limiting the height of the apex tip above the reference height.

The term "adjacent blades" herein refers to the blades that are first discovered by moving forward (i.e., in the direction of fan rotation) from the periphery of one blade.

The term "downward" does not necessarily mean herein that the blade begins to actually descend as the distance increases from such a change downward toward the tip end. But means that the height is increased at a lower rate than before going downwards, which may still be positive, although this does not exclude a zero or negative rate of height increase.

Thus, the leading edge of the air-moving portion of each vane may have a peak height above the reference height at a location between the pivot axis end of the air-moving portion and the tip end of the vane.

Further, the height of the leading edge of the air moving portion above the reference height may decrease from the peak height as the distance increases along the leading edge toward the tip end of the blade.

The "specified radius" may be approximately the radius of the luminaire portion that is included within the combined ceiling fan and luminaire and that is located below the blades and that has a circular shape when viewed in plan.

The "reference height" may be, for example only, the height of the upper surface of a horizontal plate-like member to which each blade is pivotally mounted as in the case of the configuration described by Villella.

The air moving portion of each blade may have a trailing edge which approximates a circular arc when viewed in plan which substantially centers the blade on the fan rotational axis when in its said stowed position. This arrangement allows efficient use of the available space on the luminaire part, which is circular when seen in plan view.

Preferably, for each vane, in its stowed position, the radial distance between the leading and trailing edges of the air-pushing portion progressively decreases from a maximum value towards the tip of the vane tip part way along the length of the air-pushing portion (partway) (i.e. the vanes progressively decrease as seen in plan view).

More preferably, when all the blades are in their stowed position, for each blade there is a first point on the leading edge of its air-pushing portion at which the blade overlaps its adjacent blade, the first point being located at a greater radius when viewed in a notional radial plane containing the axis of rotation of the fan than a second point in the same notional plane on the leading edge of the overlapping adjacent blade.

Still more preferably, the first point may be above a reference height without exceeding a height of the second point.

These arrangements may improve the compactness of storage of the blades.

Preferably, the air-moving portion of each blade has a maximum angle of inclination (angle of inclination) with the horizontal at a position midway along the air-moving portion in the deployed position of the blade, the angle of inclination decreasing with increasing distance from that position of maximum angle of inclination to the apex end of the blade.

It is also preferred that the air moving portion has a positive inclination to the horizontal at its pivot axis end.

The position partway along the air-moving portion of each blade may be radially inward of a position at which a chord length of the blade measured along an arc centered on the axis of rotation of the fan is at a maximum, wherein the angle of inclination of the air-moving portion of each blade with respect to a horizontal plane is at a maximum at the partway along the air-moving portion of each blade when the blades are in their deployed positions. It is believed (and not asserted) that this feature may smooth out the distribution of the downward thrust to the air along the blade, thereby reducing the drag induced on the blade.

The number of vanes is preferably four, with the pivot axes of the vanes being spaced apart from each other by 90 degrees on the periphery, although other numbers of vanes, such as three or five, may be suitable.

The portion of each blade between its pivot axis and its tip end subtends an angle of about 160 to 170 degrees with the fan axis of rotation when the blade is in its stowed position. Values in this range leave reasonable blade area in the storage space available above the light fixture portion, but do not require a stack of more than two blades at any point. This helps to achieve a compact blade storage.

Preferably, each blade pivots through an angle of about 180 degrees to move from its stowed position to its deployed position. This gives a good blade swept area for a given blade size.

Preferably, the air-moving region of each blade is bowed upwardly (i.e. downwardly concave) between its leading and trailing edges as viewed in a transverse plane centered on the fan axis of rotation and intersecting the air-moving region at a radius between the designated radius and the tip of the blade tip.

It is also preferred for effective air propulsion wherein the air-propelled region of each blade has a rounded front edge and a pointed rear edge along at least part of its length along the blade, as viewed in a transverse plane on a cylindrical surface centered on the fan axis of rotation and intersecting the air-propelled region at a radius between the specified radius and the tip of the blade tip.

The minimum height difference between each blade and its adjacent blade when the blades are in their stowed positions may advantageously occur approximately where the blades overlap their adjacent blades. If the overlapping leaves sag slightly, as might be the case if a leaf moulded from some plastics material were left unused for a period of time, this arrangement has been found to support the outer portion of the leaf very reasonably once contact between the leaf and its underlying adjacent leaf occurs.

The present invention provides in another aspect a combined ceiling fan and light fitting having a plurality of elongate and arcuate planform blades which are pivotally movable about an upright axis between a first stowed position above the light fitting housing and a second deployed position in which the blades extend outwardly beyond the light fitting, characterised in that: when in its deployed position, the leading edge of the blade first rises with increasing radius beyond the light housing and then cranks downward.

In this aspect, when the vanes are in their stowed position, each vane overlaps a portion of its adjacent vane that is received within a gap above the light housing and below the underside of the overlapping vane, the gap existing by virtue of the crank shape of the overlapping vane.

Each blade may be pivotally mounted to a rotating plate-like member with the gap above the plate-like member.

In a third aspect, the present invention provides a combined ceiling fan and light fitting having air moving blades that, in use, exhibit a gull-wing dihedral angle. Such dihedral forms are believed to be advantageous in themselves even in addition to their ability to achieve compact storage of the retracting blades. "gull-wing dihedral" is considered to mean a rising blade or wing rising between its root end and a point or region along its length toward its tip end and then either falling, remaining at the same height, or rising more slowly.

In another aspect, the present invention provides a combined ceiling fan and light fitting having a plurality of fan blades, wherein:

each vane is pivotally mounted so as to be pivotable about an upright pivot axis of the vane between a stowed position and a deployed position;

each blade, when in its stowed position, is located within a specified radius from the axis of rotation of the upright fan and above the light fixture portion, and has an air moving portion extending beyond said specified radius in the extended position of the blade; and is

Each vane is generally elongate and arcuate when viewed in plan, with a concave side and a convex side, and, in its stowed position, extends peripherally within said designated radius between the pivot axis of the vane and the tip end of the vane,

the method is characterized in that:

(a) each vane, when deployed, is positioned such that the concave side of the vane faces forward in the direction of rotation of the vane, and such that the radially outer portion of the length of the vane extends both outwardly and forwardly;

(b) a first position exists midway along the air-moving portion of the blade where the chord length of the blade measured in the peripheral direction has a maximum value, and a second position exists midway along the air-moving portion of the blade where the blade has a maximum positive pitch angle with the horizontal plane; and

(c) the radius of the first location is larger than the radius of the second location.

That is, the pitch and chord length distributions disclosed herein are believed to be advantageous in their own right, in addition to blade storage problems.

The invention also provides a blade suitable for use in a fan/light as disclosed.

It is expressly intended that the specific four blade embodiments described in detail below are considered as aspects of the invention which may be claimed both in terms of the proportions of the blades and their relative positions in their stored and operational positions.

The present invention may be preferably applied to a fan/lamp having certain constructional features as described in international patent publication WO2007/006096 (based on joewillella international patent application No. PCT/AU 2006/000981).

In yet another aspect of the present invention, there is also provided a fan/light comprising a plurality of retractable fan blades, wherein:

each said blade being pivotally mounted to a fan member rotatable about an upright fan rotational axis such that said blade is pivotable between a retracted position and an operative position about an upright blade pivot axis of said fan member;

each said vane has an elongate and generally arcuate air moving vane portion which, when the vane is in its retracted position, is located within a space defined by:

(a) an inner cylindrical surface coaxial with the fan rotation shaft and contacting an inner edge of the blade portion;

(b) an outer cylindrical surface coaxial with the fan rotational axis and contacting an outer edge of the blade portion;

(c) a first radial plane containing the fan rotational axis and the blade pivot axis; and

(d) a second radial plane containing the fan rotational axis and contacting an apex of the blade,

such that associated with each point on the blade portion is an angle θ, the angle θ being the angle between the first radial plane and a radial plane containing the fan axis of rotation and that point; and

the inner edge increases in height with increasing θ above a reference height in a continuous region of the blade portion between the first radial plane and the second radial plane, and a radial projection of the inner edge on a cylindrical surface coaxial with the fan rotational axis is concave downward.

Preferably, within said continuous region of said blade, said inner edge increases in height with increasing θ above said reference height until a maximum value of inner edge height is reached for the first time at a point where its value of θ is less than the value of θ at the blade tip.

Within the continuous region and for values of θ greater than a minimum value at which the inner edge has its maximum height above the reference height, the height of the inner edge may decrease with increasing θ. This particular embodiment corresponds to the preferred embodiment described in detail herein.

In such a fan/light, other preferred feature ratios and relative positioning of the blades as described herein may also be applied, including with respect to the blade trailing edge shape.

Further features, preferences and inventive concepts are disclosed in the following detailed description and the appended claims.

In the present specification, including the claims, the word "comprise" (and derivatives such as "comprises", "comprising", and "comprising") when used in reference to a set of integers, elements or steps, is not to be taken as excluding the possibility that other integers or steps are present or could be included.

In order that the invention may be better understood, there will now be described non-limiting preferred embodiments of the invention as illustrated in the accompanying drawings, in which:

FIG. 1 is a perspective view from above of a fan/light having retractable fan blades according to the present invention, showing the blades thereof deployed to their operating position;

FIG. 2 is a perspective view from below of the fan/light shown in FIG. 1 with its blades extended to their operating position;

FIG. 3 is a perspective view from above of the fan/light shown in FIG. 1, with the fan blades thereof shown in their folded, inoperative position;

FIG. 4 is a perspective view from below of the fan/light shown in FIG. 1 with its fan blades shown in their folded, non-operating position;

FIG. 5 is a plan view of the fan/light of FIG. 1 with its fan blades shown deployed to their operating positions;

FIG. 6 is a plan view of the fan/light of FIG. 1 with its fan blades shown in their folded, non-operating position;

FIG. 7 is a side view of the fan/light of FIG. 1 with its fan blades shown deployed to their operating positions;

FIG. 8 is a side view of the fan/light of FIG. 1 with its fan blades shown in their folded, non-operating position;

FIG. 9 is a perspective view from below of a fan/light subassembly (subasseby) having retractable fan blades as described in International patent publication No. WO2007/006096 to Villella;

FIG. 10 is a schematic plan view of the fan/light shown in FIG. 1, showing one blade in both the extended and retracted positions and the other blade in the retracted position and in only dotted lines;

FIG. 11 is a schematic plan view of the fan/lamp of FIG. 1 with all blades shown in a retracted position in dotted lines and one blade also shown in its deployed position, and showing the position of a set of cylindrical surfaces intersecting the extended blades and located at radially spaced locations along the extended blades;

FIG. 12 is a set of cross-sections (labeled a-1) of the retracting blades of the fan/light shown schematically in FIG. 10 on a radial plane as defined in FIG. 10;

FIG. 13 is a graph of the height above a reference height of the inner and outer edges of the blades of the fan/light shown in FIG. 1 as a function of circumferential position when the blades are in the retracted position;

FIG. 14 is a graph of the radial distance between the inner and outer edges of the blades of the fan/light shown in FIG. 1 as a function of circumferential position when the blades are in the retracted position;

FIG. 15 is a graph of the height above a reference height of the inner and outer edges of all of the blades of the fan/light shown in FIG. 1 as a function of circumferential position when the blades are in their retracted position;

FIG. 16 is a set of cross-sections taken at planes tangent to the arcs shown therein numbered 1 through 8 of the extended blade shown in FIG. 11;

FIG. 17 is a graph of the inclination angle from horizontal of the extended fan blade shown in FIG. 11 as a function of radial position on the blade;

FIG. 18 is a graph of chord length of the extended blade shown in FIG. 11 as a function of radial position on the blade.

Detailed description of the preferred embodiments

Fig. 1 to 8 show a fan/lamp 10 according to the invention. The fan/lamp 10 has a non-rotating bowl-shaped translucent housing 12 in which at least one electric lamp (not shown) is mounted, and the fan/lamp 10 is supported by a tubular support 13 in a known manner to the ceiling. The fan/light 10 also has fan blades 1, 2, 3 and 4 which are rotatable by an electric motor (not shown) about an upright shaft 15 coaxial with the tubular support 13. The electric motor and the lamp may operate independently or together with a source of electric power supplied through the tubular support 13. The motor is of a known type widely used in ceiling fans, having a rotating outer casing (not shown) with a central cavity in which a tubular support 13 is housed. The housing 12 is circular in plan view and is centered on the shaft 15.

Each vane 1-4 extends outwardly to the operative position shown in figures 1, 2, 5 and 7 when the motor is on and retracts (folds) to the position shown in figures 3, 4, 6 and 8 when the motor is off. The direction of rotation is shown by arrow 7. Each of the blades 1 to 4 is pivotably supported on a blade support plate 14, and the blade support plate 14 supports the blade 1 to 4 and rotates with the blade 1 to 4, has a disk shape, is coaxial with a rotation shaft 15 of the motor, and is fixed to a housing of the motor. When the blades 1-4 are in the folded position shown in figures 3, 4, 6 and 8, the decorative dust cover 18 is secured to the support 4 on the blades 1-4.

The pivoting of the blades 1-4 on the blade support plate 14 is about axes 21, 22, 23 and 24, respectively, parallel to the rotational axis 15 of the motor. When the motor is switched on, the blades 1-4 are pivoted outwards under the influence of centrifugal force, pivoting about their respective pivot axes 21-24, until the working position shown in fig. 1, 2, 5 and 7 is reached. When the motor is switched off, the vanes 1-4 retract to their stored positions shown in figures 3, 4, 6 and 8, again pivoting about their respective axes 21-24.

In international patent publication No. WO2007/006096 (international patent application No. PCT/AU2006/000981 to villlella), which is hereby incorporated by reference in its entirety, a fan/lamp is described which is substantially consistent with the principles and arrangements described above, albeit with three blades instead of the four blades 1-4 of the fan/lamp 10. The invention in its preferred embodiment is made according to the principles and arrangements set forth in the Villella disclosure, except for the use of four vanes 1-4 instead of three.

In particular, the synchronization of the pivoting movement of the blades 1-4 with their retraction allows a simple adaptation to four blades by means of the method disclosed by Villella, now briefly described. Fig. 9 (similar to fig. 7 of the Villella publication) shows a subassembly 30 of a Villella fan/lamp including a motor 34, a blade support plate 36 and three blades 31, 32 and 33. (Note: part numbers used herein to describe the subassembly 30 are different than the numbers referenced in Villella's publication). The blade support plate 36 is annular in shape and is fixed to the motor 34 (of the rotary casing type described hereinbefore) for rotation therewith in its own plane.

Secured to the underside of the blade support plate 36 is a sun gear 38. (the term "sun gear" is used herein because it is in the field of so-called planetary gear transmission systems, wherein "sun gear" refers to a gear that meshes with a number of "planet" gears arrayed around its periphery.) when the support plate 36 is mounted to the motor 34, the sun gear 38 is coaxial with the motor 34 and is capable of rotating about its axis relative to the support plate 36. Meshing with the sun gear 38 are planet gears 41, 42 and 43, each of which planet gears 41, 42 and 43 rotate as one of its associated blades 31-33 pivots between its storage and operating positions. Each of the gears 41-43 is fixed to a stub shaft (not visible) that passes downwardly from its associated one of the blades 31-33 and is rotatable within the support plate 36. The gears 41-43 are evenly distributed around the periphery of the sun gear 38 and themselves all have equal radii from each other from the rotational axis 35 of the motor 34. The effect of this arrangement is that if the blades 31-33 are identical and identically positioned in their stations relative to the support plate 36, the blades will always remain synchronized as they pivot between their working and retracted positions.

In order to retract the vanes 31-33 when the motor 34 is off, a coil spring 44 is provided. One end of each spring is fixed to a structure (formation)46 suspended from the support plate 36 and the other end is fixed to a structure 48 suspended from the sun gear 38. The coil spring 44 is arranged to be tensioned when the blades 31-33 are in their retracted position and to extend as centrifugal force pushes the blades 31-33 out when the motor 34 is started. When the motor 34 is stopped, the spring 44 urges the sun gear 38 to rotate relative to the support plate 34 to retract the blades 31-33.

For more detailed information about such an arrangement for blade synchronization and retraction and options concerning the arrangement, reference is made to the referenced Villella publication.

The manner in which this arrangement is adapted to the four vanes 1-4 of the embodiments of the invention described herein will be readily apparent to those skilled in the art. Instead of three, four planet gears (not shown, but corresponding to the gears 41-43) may be provided, evenly distributed around a sun gear (not shown, but corresponding to the sun gear 38) and each associated with one blade.

In the following description, it will be assumed that the blades 1-4 are pivotally mounted to the support plate 14, which is essentially similar to the support plate 36, and are synchronized and retracted in the same manner as the blades 31-33 of the subassembly 30. However, it should be emphasized that the aerodynamic design of the blades 1-4 and the way in which they "nest" together when retracted is in no way limited to this particular fan/light configuration. The configuration and arrangement of the blades 1-4 is applicable to other configurations of fans/lights and fans that require retractable blades without any lighting function.

The blades 1-4 and their arrangement in the fan/light 10 will now be described. The blades 1-4 are fans/lights 10 that are intended to provide an advantageous balance between good air moving performance, compactness when the blades are in their stowed (i.e., retracted or folded) position, along with a diameter of the translucent housing 12 that is large enough to provide a reasonably diffuse lighting effect. The blades 1-4 are intended to be positioned substantially on the translucent housing 12 when retracted. In the embodiment shown and described herein, the housing 12 has a diameter that is about 39% of the overall diameter of the fan/lamp 10 when its blades 1-4 are extended for operation. The diameter of the hub of a conventional ceiling fan or the hub of a fan/light without retractable blades is typically less than 39% of the total diameter across the blades. The larger the diameter of the housing 12 for a given overall diameter, the easier it is to meet the requirement of compact folding of the blades 1-4 on the housing 12, but the more difficult it is to provide good air moving performance at typical fan rotational speeds. For the above ratios, a range from about 36% to about 42% is considered feasible by direct adaptation of the blade shape as described herein, but numbers in the range of 38% to 40% are preferred.

The geometry of the blades 1-4 will be described below by reference to the quantities and cross-sections defined in fig. 10 and 11. In the schematic plan view of fig. 10, the housing 12 is represented simply by its circular periphery 26. The blades 1-4 are all shown in outline in their retracted position, the blade 1 being in solid line and the others being in dot-dash line, and the blade 1 also being shown in solid line in its deployed position. The blades 1-4 are substantially identical to each other and are generally half-moon shaped (scimitar-shaped), i.e., have an arcuate form so as to lie within the housing periphery 26 and surround the motor (not shown, but centered on the shaft 15) when retracted. The pivot axes 21-24 are adjacent to the root ends 51-54 (fig. 11) of the blades 1-4, respectively, and in their retracted positions the blades 1-4 extend clockwise to tips (free ends) 61-64, respectively. The part number with the suffix "a" is used for the vane 1 in its extended position and the part number with the suffix "b" is used for the vane 1 in its retracted position.

The blades 1-4 of the fan/light 10 are shown as rotating clockwise (by arrow 7) when viewed from above. It will be appreciated that anticlockwise rotation may equally be selected, in which case the term "anticlockwise" may apply where "clockwise" now appears in this description, including in the definitions of the terms "next blade" and "previous blade" given below. (Note that for counter-clockwise rotation, the vanes should be made to be reversed for vanes 1-4, since it is preferred that the leading edge of each vane be its concave edge.)

For any given one of the vanes 1-4, the term "next vane" refers to a vane whose pivot axis is 90 degrees from the pivot axis of the given vane in the direction of rotation (clockwise herein), and the term "previous vane" refers to a vane whose pivot axis is 90 degrees from the pivot axis of the given vane in the opposite direction (counterclockwise herein) from the direction of rotation. Thus, for blade 1, the next blade is blade 2 and the previous blade is blade 4. For convenience, the blade shape will be described primarily by reference to blade 1, noting that blades 1-4 are substantially identical.

In order to show how the blades 1-4 are arranged in a nested fashion relative to each other when retracted, it is convenient to use a cross-sectional view in a radial plane, i.e. a plane including the fan shaft 15. Such a plane 42 is shown in fig. 10 and is shown at an angle theta (theta) to a similar plane 44 that includes both the shaft 15 and the shaft 21 of the blade 1.

In order to discuss the blade shape in the deployed position from an aerodynamic point of view, it would be beneficial to consider the blade cross-section taken on a surface that is cylindrical and coaxial with the fan shaft 15 and located at a radially spaced position along the blade. The arcs numbered 1 to 8 in fig. 11 show such positions on the blade 1. The radii of position 1 and position 8 are 39% and 97% of the total fan radius, respectively (i.e. substantially at the edge of the casing 12) and positions 2-7 are radially evenly distributed between positions 1 and 8.

Each of the blades 1-4 is pivoted through 180 degrees between its retracted and operative positions. From the shaft 21 to the tip 61, a representative blade 1 extends from 0 degrees to approximately 168 degrees when retracted. The angle 168 is selected to be close to but below 180 degrees so that the tip 61 providing it is well clear of the blade 1 at the housing periphery 26 when the blade 1 is deployed, but only two of the blades 1-4 overlap each other at any point when the blades are retracted. This is important to keep the total height of the set of blades 1-4 when retracted to a compact small value. Note that if tip 61 is at θ 180 degrees, all three of blades 1, 2 and 3 will overlap at θ 180 degrees.

As shown in fig. 1, 5 and 7, the representative blade 1 has two distinct portions, a root end portion 80 and a blade portion 82, the blade portion 82 extending outwardly from the periphery 26 of the shell 12 in the operating position and being aerodynamically shaped to promote air propulsion. The blade portion 82 is supported in a cantilever fashion to the blade portion 80 which is pivotally secured to the blade support plate 14. In a preferred embodiment, portions 80 and 82 are formed as a single piece, such as from a suitable plastic material by injection molding.

The root end portion 80 includes a plate 84 located above and generally parallel to the support plate upper surface 46. An aperture 86 in the plate 84 allows a stub shaft (not shown) to pass through the aperture and pass to the underside of the support plate 14 to be secured there to a planetary gear (not shown) of the blade synchronisation mechanism as hereinbefore described. Root end portion 80 also includes a blade end plate structure 88, the function of blade end plate structure 88 being to provide a suitably secure connection between portions 80 and 82, and blade portion 82 being inclined at an angle to plate 84 (see below).

Fig. 12 shows a set of 12 radial sections (i.e. on plane 42) of a representative blade 1 and its next blade 2 and previous blade 4 in their retracted positions, each section being marked with its correct value of θ for blade 1. The radius from the fan axis 15 increases to the right in sections (a) to (1). In each section, the blade support plate 14 is shown with its outer edge 90 at the same horizontal position on each page to facilitate comparison between sections. The outer edge 90 is located just radially within the housing periphery 26 but proximate the housing periphery 26 (not shown in fig. 12).

Sections (a) to (c) of fig. 12 show how the section 80 of the blade 1 transitions to a cantilevered air pushing section 82.

As best shown in fig. 10, the outer edge 94 of the portion 82 of the representative blade 1 is very close to the arc of a circle centered on the fan shaft 15 and having a radius very close to the radius of the housing periphery 26 when the blade 1 is retracted, except for the portion adjacent the rounded tip 61. Therefore, the outer edge 94 of the portion 82 of the vane 1 is located at a radius almost completely equal to the outer edges of the next vane 2 and the previous vane 4 except for the portion adjacent to the tip 61, as shown in sections (d) to (1) of fig. 12.

Sections (a) to (f) of fig. 10 and 12 show the last blade 4 overlying a representative blade 1 between 0 degrees and slightly less than 90 degrees, but without contact between blades 1 and 4. Between 90 degrees and 165 degrees (sections (g) to (1)), the blade 1 itself overlies the next blade 2 without contact between the blades 1 and 2.

Fig. 13 is a graph showing the height of the inner edge 92 and the outer edge 94 of a representative blade 1 above the surface 46 of the support plate 14 as a function of the angle theta. For a given value of θ, the inner edge 92 is higher than the outer edge 94, in line with the inclination of the blade 1 to the horizontal, in order to push the air downwards when deployed (see below). Absolute height numbers are used in fig. 13 for the fan/light 10 with an overall swept diameter (over swept diameter) of 1200mm when the blades 1-4 are deployed.

Fig. 14 is a graph showing the radial distance between the inner edge 92 and the outer edge 94 of a representative blade 1 in its retracted position as a function of the angle theta. In fig. 13 the absolute radial distance is used for the fan/light 10 with a total swept diameter of 1200mm when the blades 1-4 are deployed. The curve between the data points does not extend to the data point where θ is 165 degrees because that point is affected by the rounding of the apex 61.

FIG. 15 is a graph showing the same data as FIG. 13, but now for all of the blades 1-4, at their respective peripheral angle (θ) positions. The initials "LE" and "TE" are used in fig. 15 for the inner edge 92 and the outer edge 94, respectively, since the inner edge of the blade is its leading edge and the outer edge is its trailing edge when in the deployed position. Note that the respective θ angles of the vane pivot axes 21, 22, 23, and 24 are 0 degrees, 90 degrees, 180 degrees, and 270 degrees.

Fig. 12-15 together illustrate how the blades 1-4 in their retracted positions "telescope" together compactly without any two blades touching each other. It has been found that the arrangement shown also gives good air pushing performance.

As illustrated by the edge height in fig. 13 and 15, the representative vane 1 rises smoothly from its pivot axis 21 (at 0 degrees) to a point (at about 90 degrees) at which the vane 1 must overlap and disengage the next vane 2. However, rather than continuing further up towards its tip 61 at the same rate, the blade 1 stops any higher rise, as shown towards stability, and then reduces the height of the inner edge 92 with increasing θ. This arrangement limits the overall height 96 (fig. 12) above the support plates 14 of the group of blades 1-4 when retracted. For the representative blade 1, the maximum value of the height 96 occurs at about θ of 105 degrees.

It will be noted in fig. 13 and 15 that after remaining approximately constant between about 90 degrees and 120 degrees, the outer edge height 94 again increases beyond about 120 degrees. As seen from sections (j) to (l) in fig. 12, and as seen by the slight projection of the blade 1 shown in fig. 4, this optional feature means that some slight sacrifice in compactness in the blade nesting arrangement is incurred (although without any increase in overall height 96), which is considered aerodynamically advantageous, as subsequently stated herein, and is therefore preferred.

Fig. 13 can be interpreted as a partial picture of the blade 1, since such a picture would appear if projected on an imaginary cylindrical surface coaxial with the fan axis, and this surface is subsequently laid flat. It is evident that the blade 1 in this figure resembles a gull wing, or a special form of wing with varying dihedral, first rising with increasing distance from its root end and no longer rising from a point or rising at a lower rate towards its tip end.

Fig. 15 shows that for values of θ greater than about 150 degrees, the inner edge height 92 of a representative blade 1 becomes lower than the leading edge height of its next blade 2. This can be seen in sections (k) and (l) of fig. 12. This does not mean that there is contact between the blades 1 and 2, since the reduction in the radial width of the blade 1 means that the inner edge 92 of the blade 1 is radially outward of the corresponding edge of the blade 2.

In addition to folding neatly, the blades 1-4 must also move air downwardly reasonably efficiently when unfolded and rotated about the fan axis 15, so the shape of the blades 1-4 as they influence the air flow will now be discussed. Arcs numbered 1-8 in fig. 11 represent a set of spaced cylindrical surfaces that are coaxial with and radially spaced from the shaft 15. Although the downward air flow past the fan/light 10 will generally not be precisely axial (i.e., parallel to the axis 15) and therefore occurs on such surfaces, one suitable way to discuss the blade shape is by reference to the intersection with the cylindrical surfaces 1-8 of the representative blade 1 in its deployed position.

It is also useful in the following for discussing the representative blade 1 when it is deployed to mention the values of the theta angle used above to describe its geometry when retracted. Theta is actually a measure of the position of the blade 1 along the half-moon. In fig. 11, a non-solid point 101 is shown, which point 101 would fall on the shaft 15 if the blade 1 were retracted, and the point 101 is replaced by 180 degrees from the shaft 15 about the blade pivot axis 21 when the blade 1 is deployed. The value of the angle theta corresponding to a particular feature on the unfolded blade 1 can be found using the schematic plan view of fig. 11 by first constructing a line connecting point 101 to the feature in question, and secondly constructing a line 102 connecting point 101 and passing through the axes 21, 15 and 23.θ is the angle between the two lines.

Fig. 16 shows a cross-sectional view of the blade 1 taken on a chord 100 (see fig. 10), which chord 100 is tangent to the cylindrical surface at positions 1 to 8. These lie very close to the shape of the cylindrical surfaces that intersect between positions 1 to 8 and the blade 1, as these surfaces would appear if laid flat. In the cross-section of fig. 16, the blade 1 is moved from right to left so that the leading edge 92 and the trailing edge 94 are positioned as shown. Although the rear edge 94 is certainly not straight in reality, the view in fig. 16 is positioned so that the rear edge 94 in all cross-sections is vertically aligned to facilitate contrast therebetween.

FIG. 17 is a graph showing the angle of inclination of a representative blade 1 from horizontal at positions 2 to 8, alpha (α), the meaning of which is illustrated in the cross-section at position 7 of FIG. 16. The alpha values plotted in fig. 17 are not taken from the approximate cross section of fig. 16, but may be estimated for the values in the manner shown if the cross section of fig. 16 is a flattened result (leveling) of the real surface intersecting between the cylindrical surfaces numbered 2 to 8 and the blade 1.

Fig. 18 is a graph showing the values of the true chord length (i.e. the distance measured directly from the leading edge 92 to the trailing edge 94) at the intersection of the blade 1 with the cylindrical surfaces numbered 1 to 8. The chord length values are not taken from the approximate cross-section of fig. 16, but rather an estimate of the values that would be obtained if the true surfaces of the intersection between blade 1 and the cylindrical surfaces numbered 1 to 8 were obtained and laid flat.

It has been found that the fan/lamp 10 with blades 1-4 having the geometry shown does push air reasonably well, despite the relatively large ratio between the diameter of the housing 12 and the overall diameter swept by the deployed blades 1-4 and the half-moon shape of the blades (in plan view).

Typically, the blades 1-4 propel air downward (and themselves experience a corresponding reactive lift) as they rotate. The effectiveness of a blade (for a given rotational speed) is here considered to depend at least on its airfoil cross-sectional shape, its inclination to the horizontal plane, its size (e.g. its chord length measured from the leading edge to the trailing edge), these distributions along the length (span) of the blade and its shape as seen in plan view.

As seen in the cross-section of the representative blade 1 in fig. 16, the blades 1-4 have an airfoil cross-sectional shape, being cambered so that their lower faces are concave and their upper faces are convex. Their leading edges (such as the leading edge 92 of the representative blade 1) are rounded and their trailing edges (such as the edge 94 of the representative blade 1) are pointed. In general, the blades 1-4 preferably have an arcuate airfoil cross-section.

The representative blade 1 has a positive pitch angle from the horizontal (and is an arched airfoil cross section) near its pivot end where the representative blade 1 passes through the casing periphery 26 when deployed, and this is believed to be a factor in its air propulsion performance. This positive inclination (alpha greater than zero) is evident in the section numbered 1 in fig. 16.

It is believed desirable that the lift distribution (and consequently the distribution of the air-pushing effect that occurs) along the length of the blade should generally vary smoothly and in particular have no strong concentration of effect near the outer (tip) end. This concentration is believed to create a tendency for the high pressure air below the tip region to "leak" up beyond the tip end (61 in the representative blade 1) to the region above the tip region, only partially agitating the air (and wasting power) rather than moving it down as a whole. Thus, the distribution of pitch angles alpha shown in FIG. 17 shows that the peak blade pitch angle of about 20 degrees is at a radius of about position 3 (see FIG. 11) and smoothly decreases to about 10 degrees at position 8 as the radius increases. (position 3 corresponds very closely to θ 60 degrees.)

The pitch angle distribution shown in fig. 17 is due in part to the optional upward bow of the blade trailing edge beyond about θ -120 degrees discussed above. Although a slight more compact nesting of the blades 1-4 can be achieved if this upward bow is not included, it appears beneficial for the performance of the blades due to the effect on the pitch angle distribution that it achieves.

Another way of influencing the lift distribution along the blade is through control of the blade width (chord length) distribution. If one imagines a half-moon shaped blade of constant width along the length of the blade (e.g. for all values of theta) deployed in the manner shown for blades 1-4 in fig. 11, the effect of the half-moon shape will be that the chord length of the blade as measured in the circumferential direction when the blade is deployed will be greatest at the tip and root ends of the blade and smaller between them. To counteract this effect and thereby limit the tendency to concentrate the lift effect at the tip and root ends, the blades 1-4 do not have a constant width. Referring to fig. 14, the blade width (as viewed in plan) is greatest at about θ -90 degrees and gradually decreases toward the tip end (61 of representative blade 1). As seen in fig. 11, θ corresponds approximately to position 5 at 90 degrees. This reduction serves the dual purpose of compact nesting of the blades when retracted (as discussed above) and obtaining the desired lift distribution of the blades.

Fig. 18 shows that the blade chord length increases from a minimum in the region of positions 2 and 3 before decreasing at position 8 due to tip rounding. However, the rate at which the chord length increases with radius is less than would be exhibited if the blade width did not vary with angle θ in the manner described herein. Referring also to fig. 16, the alignment of the sections numbered 1 to 8 on the page allows the distribution of chord length with radius to be seen.

As mentioned above, the blade may conveniently be made from a suitable plastics material by injection moulding. Since unobtrusiveness (unobtrusiveness) is a desirable feature of the fan/lamp according to the invention, one way to enhance the unobtrusiveness is to provide the blades to be formed of a translucent or at least translucent material. This feature is considered to be inventive in itself.

Although the blade storage arrangement and method described herein provides for storing blades without contact between the blades, the blade storage position described allows for a slight sag of one blade so that contact with the other is unlikely to result in a deployment failure. It will be noted in fig. 12 that the sectional view showing the minimum gap between the vane 1 and its next vane 2 is a section (g), corresponding to θ being 90 degrees. This is considered to be a suitable location for the minimum clearance and thus where the first contact between the blades 1 and 2 occurs, if after storage for a period of time without the use of the fan, the blade 1 should sag slightly. It is considered that after such contact between the blades 1 and 2, the tendency to continue to sag should be limited and the moment arm for any frictional forces caused by blade contact with the shaft 21 is less than the contact between the tip 61 of the blade 1 and the underlying blade 2, thus limiting the possibility of a deployment failure of the blade 1 at fan start-up.

The possibility of relatively thin blades (so that they may sag over time if not used) also means that the blades may bend upwards towards their top tips when in use. This can be considered to be advantageous to direct air slightly more outwardly and downwardly than if the blades were rigid.

The particular shape of the translucent lower portion 9 of the housing 2 is not considered to be the only one possible. Even shapes that do not have a circular shape in plan, as shown in fig. 1-7, may be used as an alternative aesthetic option.

Yet another invention will now be disclosed. In fans/lights such as those described by Villella in his aforementioned PCT application, the "sun gear" may comprise a single member to which a toothed portion is fixed for engagement with a "planet gear" instead of a complete gear. This possibility has been found and can reduce the rise in manufacturing costs because an appropriate ratio of sun and planet gears can be selected which does not require the sun gear to rotate far enough for any one of its teeth to hit more than one planet gear during deployment and retraction.

It will be apparent to those skilled in the art that many other variations and alternatives can be made to the fan/lamp described above without departing from the scope of the invention as described.

Claims (26)

1. A combined ceiling fan and light fitting having a plurality of fan blades, wherein:

each vane is pivotally mounted so as to be pivotable about an upright pivot axis of the vane between a stowed position and a deployed position;

each blade, when in its stowed position, is located within a specified radius from the axis of rotation of the upright fan and above the light fixture portion, and each blade has an air moving portion that extends beyond the specified radius in the extended position of the blade; and is

Each vane is elongate and arcuate when viewed in plan, and in its stowed position each vane lies within the specified radius between its pivot axis and its apex and partially overlaps an adjacent one of the vanes in its own stowed position;

the method is characterized in that:

(a) the specified radius is approximately the radius of a luminaire portion that is included within the combined ceiling fan and luminaire and that is located below the blades, and that has a circular shape when viewed in plan; and

(b) the air moving portion of each blade has a rear edge that is approximately a circular arc when viewed in plan that generally centers on the fan rotational axis when the blade is in its stowed position.

2. A combined ceiling fan and light fitting according to claim 1 wherein the leading edge of the air moving portion of each blade has a peak height above a reference height at a location between the pivot axis end of the air moving portion and the tip end of the blade.

3. A combined ceiling fan and light fitting according to claim 2 wherein the height of the front edge of the air moving portion above the reference height decreases from the peak height with increasing distance along the front edge to the tip of the blade.

4. A combined ceiling fan and light fitting according to claim 1 wherein for each blade, the radial distance between the front edge and the rear edge of the air moving portion progressively decreases from a maximum to the blade tip end part way along the length of the air moving portion when the blade is in its stowed position.

5. A combined ceiling fan and light fitting according to claim 4 wherein when all blades are in their stowed positions, for each blade there is a first point on the leading edge of the air-moving portion of the blade at which the blade overlaps its adjacent blade, the first point being located at a greater radius when viewed in a notional radial plane including the fan axis of rotation than a second point in the same notional plane on the leading edge of the overlapping adjacent blade.

6. A combined ceiling fan and light fitting according to claim 5 wherein the first point is above a reference height without exceeding the height of the second point.

7. A combined ceiling fan and light fitting according to claim 1 wherein the air moving portion of each blade has a maximum angle of inclination with the horizontal at a position partway along the air moving portion in the deployed position of the blade, the angle of inclination decreasing with increasing distance from the position of maximum angle of inclination to the tip end of the blade.

8. A combined ceiling fan and light fitting according to claim 7 wherein the air moving portion has a positive angle of inclination to the horizontal at its pivotal axial end.

9. A combined ceiling fan and light fitting according to claim 7 or 8 wherein the midway location along the air-moving portion of each blade is radially inward of a location at which the chord length of the blade measured along an arc centred on the axis of rotation of the fan is at a maximum, wherein the angle of inclination of the air-moving portion of each blade to the horizontal is at a maximum at the midway location along the air-moving portion of each blade when the blades are in their deployed positions.

10. A combined ceiling fan and light fitting according to claim 1 wherein the number of blades is four and the pivot axes of the blades are peripherally spaced from each other by 90 degrees.

11. A combined ceiling fan and light fitting according to claim 10 wherein the angle of the portion of each blade between its pivot axis and its tip end against the fan axis of rotation when the blades are in their stowed position is from 160 to 170 degrees.

12. A combined ceiling fan and light fitting according to claim 10 or 11 wherein each blade pivots through an angle of about 180 ° to move from its stowed position to its deployed position.

13. A combined ceiling fan and light fitting according to claim 1 wherein the air moving portion of each blade is upwardly arched, i.e. downwardly concave, between its leading and trailing edges when viewed in cross-section on a cylindrical surface centred on the fan axis of rotation and intersecting the air moving portion at a radius between the prescribed radius and the blade apex.

14. A combined ceiling fan and light fitting according to claim 1 wherein the air moving portion of each blade has a rounded front edge and a pointed rear edge along at least part of its length when viewed in cross section on a cylindrical surface centred on the fan axis of rotation and intersecting the air moving portion at a radius between the prescribed radius and the blade tip end.

15. A combined ceiling fan and light fitting according to claim 1 wherein the minimum height difference between each blade and its adjacent blade occurs approximately where the blade overlaps its adjacent blade when the blades are all in their stowed positions.

16. A combined ceiling fan and light fitting according to claim 1 wherein each blade overlaps a portion of its adjacent blade which is housed within a gap above the light fitting housing and below the underside of the overlapping blade, the gap existing by virtue of the crank shape of the overlapping blade.

17. A combined ceiling fan and light fitting according to claim 16 wherein each blade is pivotally mounted to a rotating plate like member and the gap is located above the plate like member.

18. A combined ceiling fan and light fitting according to claim 1 wherein the air-pushing portion of each blade has a height difference at the leading edge of the blade relative to the root end portion of each blade.

19. A combined ceiling fan and light fitting according to claim 18 including an electric motor coupled to a blade support means which in use is rotated by the motor about the fan axis of rotation, each said blade being supported by the blade support means and mounted for rotation relative to the blade support means about its blade pivot axis, and wherein the blade support means has a peripheral edge which is rounded, and wherein the rear edge of the blade is adjacent the peripheral edge when the blade is in its stowed position.

20. A combined ceiling fan and light fitting according to claim 18 or 19 wherein the leading edges of the blades are rounded.

21. A combined ceiling fan and light fitting according to claim 18 wherein the root end portion of each blade includes a plate portion adjacent its air-moving portion.

22. A combined ceiling fan and light fitting according to claim 18 wherein:

(i) the leading edge of each blade reaches a maximum height and then decreases in height towards its tip; and/or

(ii) each said blade is integrally moulded from plastics material.

23. A combined ceiling fan and light fitting having a plurality of fan blades, wherein:

each vane is pivotally mounted so as to be pivotable about an upright pivot axis of the vane between a stowed position and a deployed position;

each blade, when in its stowed position, is located within a specified radius from the axis of rotation of the upright fan and above the light fixture portion, and each blade has an air moving portion that extends beyond the specified radius in the extended position of the blade; and is

Each vane is elongate and arcuate when viewed in plan, and in its stowed position each vane extends within the specified radius between its pivot axis and its apex and partially overlaps an adjacent one of the vanes in its own stowed position;

the method is characterized in that:

(a) four of the blades are equally spaced about the fan axis of rotation;

(b) the air-pushing portion of each blade has a concave leading edge and a convex trailing edge when operated to direct air downwardly and when viewed in plan;

(c) the leading edge of each blade is higher than its trailing edge;

(d) each air moving portion having a cross-sectional shape including an upper edge and a lower edge, wherein the upper edge includes a convex portion and the lower edge includes a concave portion, the cross-section taken in a radial plane that includes the fan rotational axis and when the blades are in their stowed positions; and is

(e) The angle of each blade between its pivot axis and its tip end against the fan axis of rotation is 160 to 170,

wherein the blades are compactly nested in their stowed position and have good air moving properties when operated in their deployed position.

24. A combined ceiling fan and light fitting according to claim 23 wherein each blade in its stowed position is located within a space defined by:

(a) an inner cylindrical surface coaxial with the fan rotation shaft and contacting the inner edges of the blades;

(b) an outer cylindrical surface coaxial with the fan rotation shaft and contacting an outer edge of the blade;

(c) a first radial plane containing the fan rotational axis and the blade pivot axis; and

(d) a second radial plane containing the fan rotational axis and contacting an apex of the blade,

such that associated with each point on the blade is an angle θ, said angle θ being the angle between the first radial plane and a radial plane containing the fan axis of rotation and that point; and is

The inner edge increases in height with increasing θ above a reference height within a continuum of the blade between the first radial plane and the second radial plane.

25. A combined ceiling fan and light fitting according to claim 23 wherein the concave portion of each blade is adjacent in cross section to the convex portion of its adjacent blade in a radial plane including the fan axis of rotation when the blades are in their stowed positions.

26. A combined ceiling fan and light fitting according to claim 23 wherein the upper and lower edges are convex and concave respectively from the front edge to the rear edge of each blade.