GB2484274A

GB2484274A - Fan oscillation mechanism

Info

Publication number: GB2484274A
Application number: GB1016638.7A
Authority: GB
Inventors: Owee Kowang Tan; Kok Ming Chai; Norhayati Isa; Sharir Saupi; Yeow Lee Tan; Meng Sum
Original assignee: Dyson Technology Ltd
Current assignee: Dyson Technology Ltd
Priority date: 2010-10-04
Filing date: 2010-10-04
Publication date: 2012-04-11
Anticipated expiration: 2030-10-04
Also published as: GB2484274B; GB201016638D0

Abstract

A fan assembly comprises first and second connected and relatively moveable body sections 20, 22, an air outlet being moveable with the first body section. The fan also comprises an air inlet, means for creating an air flow between the inlet and outlet, and an oscillation mechanism 116. The oscillation mechanism comprises a bi-directional motor 118 located within the second body section, a friction drive member 122 connected to the motor and arranged to drive, by means of friction there between, a driven member 124 which is connected to the first body section. An idler 128 for engaging the driven member may be located diametrically opposite to the drive member. A casing may be connected to the first body section, the casing comprising the air outlet. The casing may comprise an opening through which air from outside of the fan assembly may be drawn by air emitted from the air outlet.

Description

A FAN ASSEMBLY

FIELD OF THE INVENTION

The present invention relates to a fan assembly. In a preferred embodiment, the present invention relates to a fan assembly having an oscillation mechanism for oscillating an air outlet of the fan assembly.

BACKGROUND OF THE INVENTION

A conventional domestic fan typically includes a set of blades or vanes mounted for rotation about an axis, and drive apparatus for rotating the set of blades to generate an air flow. The movement and circulation of the air flow creates a wind chill' or breeze and, as a result, the user experiences a cooling effect as heat is dissipated through convection and evaporation.

Such fans are available in a variety of sizes and shapes. For example, a ceiling fan can be at least 1 m in diameter, and is usually mounted in a suspended manner from the ceiling to provide a downward flow of air to cool a room. On the other hand, desk fans are often around 30 cm in diameter, and are usually free standing and portable. Floor-standing tower fans generally comprise an elongate, vertically extending casing around 1 m high and housing one or more sets of rotary blades for generating an air flow, whereas floor-standing pedestal fans generally comprise a height adjustable pedestal supporting the drive apparatus.

An oscillation mechanism may be employed to rotate the outlet from the fan so that the air flow is swept over a wide area of a room. For example, DE 2020060 16988U describes a tower fan having a base with an air outlet, a body upon which the body is mounted, and an oscillation mechanism for oscillating the body relative to the base.

The oscillation mechanism comprises a bi-directional synchronous motor which rotates a drive gear. The drive gear has teeth which mesh with the teeth of a driven gear so that

I

the driven gear is rotated by the drive gear. The driven gear is connected to the body so that the body rotates with the driven gear. A similar oscillation mechanism is described in US 4,703,152 for oscillating a body housing a fan relative to a base.

A problem associated with the use of such oscillation mechanisms is that the intermeshing gears can generate undesirable noise and vibrations during use of the oscillation mechanism. Depending on the material from which the gears are formed, the teeth of the gears can wear down during use. Furthermore, abusive rotation of the body relative to the base can damage the gears, potentially leading to failure of the oscillation mechanism.

SUMMARY OF THE INVENTION

The present invention provides a fan assembly for creating an air current, the fan assembly comprising: a body comprising a first section, a second section connected to the first section, the first section being moveable relative to the second section, and an air inlet; an air outlet moveable with the first section of the body; means for creating an air flow between the air inlet and the air outlet; and an oscillation mechanism for oscillating the first section of the body relative to the second section of the body; wherein the oscillation mechanism comprises a bi-directional motor located within the second section of the body, a friction drive member connected to the motor and a driven member connected to the first section of the body and which is driven by the drive member by means of friction therebetween..

The use of an oscillation mechanism which employs frictional coupling between a drive member and a driven member to rotate a first section of the body relative to a second section of the body can significantly reduce the noise and vibration associated with the use of the oscillation mechanism in comparison to an oscillation mechanism employing intermeshing gears.

The friction drive member preferably comprises a drive roller connected to one end of a drive shaft which is connected to, and rotated by, the motor. The driven member is preferably in the form of an annular, preferably generally circular, track or other running surface which is connected to the first section of the body so that the inner surface of the driven member engages the outer surface of the drive member. For example, in a preferred embodiment the first section of the body comprises a cylindrical wall which extends into the second section of the body so as to surround the drive member, with the driven member being connected to the inner surface of this wall so as to engage the drive member.

The rotational axis of the drive member is preferably spaced from the rotational axis of the driven member. In this case, the oscillation mechanism preferably comprises an idler for engaging the driven member to prevent the driven member from becoming misaligned with the drive member. Where the drive member comprises a roller, the idler preferably also comprises a roller which rotates about an axis spaced from, and preferably diametrically opposite to, the rotational axis of the drive member.

The first section of the body preferably comprises a shaft extending into the second section of the body, with the second section of the body comprising a sleeve for receiving the shaft. The shaft is preferably co-axial with the driven member. The shaft is preferably rotatably supported within the sleeve by at least one bearing.

The first section of the body preferably comprises said means for creating an air flow between the air inlet and the air outlet. The means for creating an air flow between the air inlet and the air outlet preferably comprises a motor-driven impeller. The impeller is preferably co-axial with the driven member of the oscillation mechanism.

The fan assembly preferably comprises a casing connected to the first section of the body, the casing comprising the air outlet of the fan assembly. Preferably, the casing comprises an interior passage for receiving the air flow from the body and for conveying the air flow to the air outlet. Preferably, the casing defines an opening through which the air from outside the fan assembly is drawn by the air flow emitted from the air outlet. The casing preferably comprises an inner casing section and an outer casing section which define the interior passage and the air outlet. Each section is preferably formed from a respective annular member, but each section may be provided by a plurality of members connected together or otherwise assembled to form that section. The outer casing section is preferably shaped so as to partially overlap the inner casing section. This can enable the air outlet to be defined between overlapping portions of the external surface of the inner casing section and the internal surface of the outer casing section of the nozzle. The air outlet preferably comprises at least one slot, preferably having a width in the range from 0.5 to 5 mm, more preferably in the range from 0.5 to 1.5 mm. The casing may comprise a plurality of spacers for urging apart the overlapping portions of the inner casing section and the outer casing section. This can assist in maintaining a substantially uniform outlet width about the opening. The spacers are preferably evenly spaced along the outlet.

The fan assembly is preferably in the form of a portable desk fan, a portable tower fan, or a portable pedestal fan.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a front perspective view of a fan assembly, in which a telescopic duct of the fan assembly is in a fully extended configuration; Figure 2 is another front perspective view of the fan assembly, in which the telescopic duct of the fan assembly is in a retracted position; Figure 3 is a side sectional view of the main body section of the body of the fan assembly; Figure 4 is a front view of an air outlet of the fan assembly; Figure 5 is a sectional view of the air outlet, taken along line P-P in Figure 4; and Figure 6 is an enlarged view of area R indicated in Figure 5; Figure 7 is a front view of the body of the fan assembly, from which the control circuit and user interface have been removed; Figure 8 is a top sectional view of the lower body section of the body, taken along line F-F in Figure 7; and Figure 9 is a side sectional view of the lower body section of the body, taken along line G-G in Figure 8.

DETAILED DESCRIPTION OF THE INVENTION

Figures 1 and 2 illustrate external views of a fan assembly 12. In this embodiment, the fan assembly 12 is in the form of a domestic pedestal fan comprising an annular casing 14 having an air outlet for emitting an air flow from the fan assembly 12, and which is connected to a body 16 having an air inlet through which the air flow enters the fan assembly 12. In this embodiment, a telescopic duct 18 is located between the casing 14 and the body 16 for conveying the air flow from the body 16 to the casing 14.

Depending on the nature of the fan assembly, the telescopic duct 18 may be omitted.

For example, where the fan assembly 12 is a floor standing tower fan or a desk fan, the casing 14 may be mounted directly on to the body 16.

The body 16 comprises a substantially cylindrical main body section 20 mounted on a substantially cylindrical lower body section 22. The main body section 20 and the lower body section 22 preferably have substantially the same external diameter so that the external surface of the upper body section 20 is substantially flush with the extemal surface of the lower body section 22. In this embodiment the body 16 has a height in the range from 100 to 300 mm, and a diameter in the range from 100 to 200 mm.

The lower body section 22 is mounted optionally on a floor-standing, disc-shaped base plate 24. The base plate 24 preferably has a diameter in the range from 200 to 300 mm.

The lower body section 22 comprises a user interface including a plurality of user-operable buttons 26 and a user-operable dial 28 for controlling the operation of the fan assembly 12. The main body section 20 comprises the air inlet 30 through which the air flow enters the fan assembly 12. In this embodiment the air inlet 30 comprises an array of apertures formed in the main body section 20. Alternatively, the air inlet 30 may comprise one or more grilles or meshes mounted within windows formed in the main body section 20. The main body section 20 is open at the upper end (as illustrated) thereof to provide an air outlet through which the primary air flow is exhausted from the body 16.

The telescopic duct 18 of the pedestal 12 is moveable between a fully extended configuration, as illustrated in Figure 1, and a retracted configuration, as illustrated in Figure 2. The duct 18 comprises a substantially cylindrical base 32 mounted on the open upper end of the main body section 20, an outer tubular member 34 which is connected to, and extends upwardly from, the base 32, and an inner tubular member 36 which is located partially within the outer tubular member 34. A tubular connector 37 connects the casing 14 to the open upper end of the inner tubular member 36 of the duct 18. The inner tubular member 36 is slidable relative to, and within, the outer tubular member 34. When the inner tubular member 36 is in the fully extended position, the fan assembly 12 preferably has a height in the range from 1200 to 1600 mm, whereas when the inner tubular member 36 is in the retracted position, the fan assembly 12 preferably has a height in the range from 900 to 1300 mm. To adjust the height of the fan assembly 12, the user may grasp an exposed portion of the inner tubular member 36 and slide the inner tubular member 36 in either an upward or a downward direction as desired so that casing 14 is at the desired vertical position. When the inner tubular member 36 is in its retracted position, the user may grasp the connector 37 to pull the inner tubular member 36 upwards.

The casing 14 has an annular shape, extending about a central axis X to define an opening 38. The casing 14 comprises an air outlet 40 located towards the rear of the casing 14 for emitting the air flow from the fan assembly 12 and through the opening 38. The air outlet 40 extends about the opening 38, and is preferably also annular. The inner periphery of the casing 14 comprises a Coanda surface 42 located adjacent the air outlet 40 and over which the air outlet 40 directs the air emitted from the fan assembly 12, a diffuser surface 44 located downstream of the Coanda surface 42 and a guide surface 46 located downstream of the diffuser surface 44. The diffuser surface 44 is arranged to taper away from the central axis X of the opening 38 in such a way so as to assist the flow of air emitted from the fan assembly 12. The angle subtended between the diffuser surface 44 and the central axis X of the opening 38 is in the range from 5 to 25°, and in this example is around 7°. The guide surface 46 is arranged at an angle to the diffuser surface 44 to further assist the efficient delivery of a cooling air flow from the fan assembly 12. The guide surface 46 is preferably arranged substantially parallel to the central axis X of the opening 38 to present a substantially flat and substantially smooth face to the air flow emitted from the air outlet 40. A visually appealing tapered surface 48 is located downstream from the guide surface 46, terminating at a tip surface lying substantially perpendicular to the central axis X of the opening 38. The angle subtended between the tapered surface 48 and the central axis X of the opening 38 is preferably around 45°.

With reference now to Figure 3, the main body section 20 houses an impeller 52 for drawing the primary air flow through the air inlet 14 and into the body 16. Preferably, the impeller 52 is in the form of a mixed flow impeller. The impeller 52 is connected to a rotary shaft 54 extending outwardly from a motor 56, and which is substantially co-axial with the longitudinal axis A1 of the body 16 (illustrated in Figure 9). In this embodiment, the motor 56 is a DC brushless motor having a speed which is variable by a main control circuit of the fan assembly 12 in response to user manipulation of the dial 28. The main control circuit is preferably housed in the lower body section 22, and is connected to the motor 56 by a cable 58. A mains power cable (not shown) for supplying electrical power to the fan assembly 12 extends through an aperture formed in the lower body section 22 to the control circuit.

The maximum speed of the motor 56 is preferably in the range from 5,000 to 10,000 rpm. The motor 56 is housed within a motor bucket comprising an upper portion 60 connected to a lower portion 62. The upper portion 60 of the motor bucket comprises a diffuser 64 in the form of a stationary disc having spiral blades. The motor bucket is located within, and mounted on, a generally frusto-conical impeller housing 66. The impeller housing 66 is, in tum, mounted on a plurality of angularly spaced supports 68, in this example three supports, located within and connected to the main body section 20. The impeller 52 and the impeller housing 66 are shaped so that the impeller 52 is in close proximity to, but does not contact, the inner surface of the impeller housing 66. A substantially annular inlet member 70 is connected to the bottom of the impeller housing 66 for guiding the air flow into the impeller housing 66.

A flexible sealing member 72 is mounted on the impeller housing 66. The flexible sealing member prevents air from passing around the outer surface of the impeller housing to the inlet member 70. The sealing member 72 preferably comprises an annular lip seal, preferably formed from rubber. The sealing member 72 further comprises a guide portion in the form of a grommet for guiding the cable 58 to the motor 56. The cable 58 passes from the main control circuit to the motor 56 through apertures formed in the main body section 20 and the lower body section 22 of the body 16, and in the impeller housing 66 and the motor bucket.

Preferably, the body 16 includes silencing foam for reducing noise emissions from the body 16. In this embodiment, the main body section 20 of the body 16 an annular foam member 74 located beneath the air inlet 30.

Figure 3 also shows a domed air guiding member 76 which is inserted into the main body section 20 through the open upper end thereof for guiding the air flow emitted from the diffuser 64 into the duct 18. The air guiding member 76 has an open lower end 78 for receiving the air flow from the body 16, and an open upper end 80 for conveying the primary air flow into the duct 18. The air guiding member 76 is connected to the base 32 of the duct 18 by means of co-operating snap-fit connectors 82 located on the base 32 and the air guiding member 76. The air guiding member 76 is connected to the open upper end of the main body section 20, for example by means of co-operating snap-fit connectors 84 or screw-threaded connectors located on the air guiding member 76 and the motor body section 20. Thus, the air guiding member 76 serves to connect the duct 18 to the body 16.

A plurality of air guiding vanes 86 are located on the inner surface of the air guiding member 76 for guiding the spiraling air flow emitted from the diffuser 64 into the duct 18. In this example, the air guiding member 76 comprises seven air guiding vanes 86 which are evenly spaced about the inner surface of the air guiding member 76. The air guiding vanes 86 meet at the centre of the open upper end 80 of the air guiding member 76, and thus define a plurality of air channels 88 within the air guiding member 76 each for guiding a respective portion of the primary air flow into the duct 18.

The casing 14 of the fan assembly 12 will now be described with reference to Figures 4 to 6. The casing 14 comprises an annular outer casing section 90 connected to and extending about an annular inner casing section 92. Each of these sections may be formed from a plurality of connected parts, but in this embodiment each of the outer casing section 90 and the inner casing section 92 is formed from a respective, single moulded part. The inner casing section 92 defines the central opening 38 of the casing 14, and has an external surface 94 which is shaped to define the Coanda surface 42, diffuser surface 44, guide surface 46 and tapered surface 48.

The outer casing section 90 and the inner casing section 92 together define an annular interior passage 96 of the casing 14. Thus, the interior passage 96 extends about the opening 38. The interior passage 96 is bounded by the internal peripheral surface 98 of the outer casing section 90 and the internal peripheral surface 100 of the inner casing section 92. The connector 37 connects the outer casing section 90 of the casing 14 to the open upper end of the inner tubular member 36 of the duct 18. The bottom of the outer casing section 90 comprises an aperture (not shown) for receiving the air flow from the connector 37.

The air outlet 40 is located towards the rear of the casing 14. The air outlet 40 is defined by overlapping, or facing, portions 102, 104 of the internal peripheral surface 98 of the outer casing section 90 and the external peripheral surface 94 of the inner casing section 92, respectively. In this example, the air outlet 40 is substantially annular, and, as illustrated in Figure 15, is arranged to direct the air flow over the Coanda surface 42.

The air outlet 40 is in the form of an annular slot, preferably having a relatively constant width in the range from 0.5 to 5 mm. In this example the air outlet 40 has a width in the range from 0.5 to 1.5 mm. Spacers may be provided for urging apart the overlapping portions 102, 104 to maintain the width of the air outlet 40 at the desired level. These spacers may be integral with either the internal peripheral surface 98 of the outer casing section 90 or the external peripheral surface 94 of the inner casing section 92.

An oscillation mechanism for oscillating the main body section 20 relative to the lower body section 22, and thereby oscillating the air outlet 40 of the fan assembly 12 relative to the lower body section 22, will now be described with reference to Figures 7 to 9.

The main body section 20 is connected to the lower body section 22 in such manner as to allow the main body section 20 to be rotated relative to the lower body section 22. In this example, the main body section 20 comprises a shaft 106 which depends downwardly from the lower surface 108 of the main body section 20. The shaft 106 is substantially co-axial with the longitudinal axis Al of the body 16. The shaft 106 is located within a sleeve 110 extending upwardly from the centre of the lower surface 112 of the lower body section 22. The shaft 106 is supported for rotation relative to the sleeve 110, and also retained in the sleeve 110, by a bearing 114. An annular bearing 115 may also be provided around the lower surface 108 of the main body section 20 for supporting the main body section 20 for rotation relative to the lower body section 22.

The oscillation mechanism 116 comprises a bi-directional, synchronous motor 118 which is connected to the control circuit (not shown) of the fan assembly 12. The control circuit controls the speed and the direction of the motor 118. The motor 118 is located within the lower body section 22. A drive shaft 120 extends upwardly from the motor 118. The drive shaft 120 has a rotational axis A2 which is parallel to, but spaced from, the longitudinal axis A1 of the body 16. A friction drive roller 122 is connected to the upper end of the drive shaft 120 for rotation with the drive shaft 120.

The drive roller 122 engages frictionally a driven member 124 of the oscillation mechanism 116. The driven member 124 is in the form of a circular track which is connected to the inner surface of a cylindrical wall 126 which depends downwardly from the lower surface 108 of the main body section 20, and which is centered on the longitudinal axis A1 of the body 16. The driven member 124 has an inner surface which is longer than the outer surface of the drive roller 122 so that the rotational speed of the driven member 124 is lower than that of the drive roller 122. In this example, the drive roller 122 has a rotational speed of around 30 to 40 rpm, whereas the driven member 124 has a rotational speed of around 3 to S rpm.

In this example, the drive roller 122 and the driven roller 124 each comprise an outer sleeve formed from silicon rubber. However, other materials may be selected for the outer surfaces of the drive roller 122 and the driven roller 124. The outer surfaces of the drive roller 122 and the driven roller 124 may be formed from different materials. For example, the outer surface of the drive roller 122 may be formed from material that has a high coefficient of friction than the material from which the outer surface of the driven member 124 is formed.

The driven member 124 is also engaged by an idler roller 128 of the oscillation mechanism 116. The idler roller 128 is rotatably supported by a bearing arrangement on the upper end of a shaft 132 so that the idler roller 128 can rotate freely relative to the shaft 132. The lower end of the shaft 132 is retained by a cylindrical support 134 extending upwardly from the lower surface 112 of the lower base section 22. The shaft 132 has a longitudinal axis A3 which is parallel to, and generally diametrically opposite to, the rotational axis A2 of the drive shaft 120 for rotating the drive roller 122. The engagement of the drive roller 122 and the idler roller 128 with the driven member 124 maintains the alignment of the driven member 124 with the longitudinal axis A1 of the body 16.

To operate the fan assembly 12 the user presses one of the buttons 26 of the user interface. In response to this, the control circuit activates the motor 56 to rotate the impeller 52. The rotation of the impeller 52 causes a primary air flow to be drawn into the body 16 through the air inlet 30. The user may control the speed of the motor 52, and therefore the rate at which air is drawn into the body 16 through the air inlet 30, by manipulating the dial 28. Depending on the speed of the motor 56, the primary air flow generated by the impeller 52 may be between 20 and 30 litres per second. The primary air flow passes sequentially through the impeller housing 66 and the diffuser 64. The spiral form of the blades of the diffuser 64 causes the primary air flow to be exhausted from the diffuser 64 in the form of spiraling air flow. The primary air flow enters the air guiding member 76, wherein the curved air guiding vanes 86 guide the primary air flow into the base 32 of the telescopic duct 18. The primary air flow passes upwards through the outer tubular member 34 and the inner tubular member 36 of the duct 18, and through the connector 37 to enter the interior passage 96 of the casing 14.

Within the casing 14, the primary air flow is divided into two air streams which pass in opposite directions around the central opening 38 of the casing 14. As the air streams pass through the interior passage 96, air is emitted through the air outlet 40. The primary air flow emitted from the air outlet 40 is directed over the Coanda surface 42 of the casing 14, causing a secondary air flow to be generated by the entrainment of air from the external environment, specifically from the region around the air outlet 40 and from around the rear of the casing 14. This secondary air flow passes through the central opening 38 of the casing 14, where it combines with the primary air flow to produce a total air flow, or air current, projected forward from the casing 14.

To oscillate the casing 14 relative to the lower body section 22 of the body 16, and thereby sweep the air current over an arc, the user presses a second button 26 of the user interface. In response to this, the control circuit activates the motor 118 to rotate the drive roller 122. Due to the frictional engagement between the drive roller 122 and the driven member 124, the rotation of the drive roller 122 about the axis A2 causes the driven member 124 to rotate about the longitudinal axis A1 of the body 16. This in turn causes the main body section 20, and the casing 14 connected to the main body section 20, to rotate relative to the lower body section 22. As mentioned above, the control circuit controls the speed of the motor 118 so that the main body section 20 rotates at a speed of around 3 to 5 rpm. The control circuit is also arranged to reverse the direction of the motor 118, and so the rotational direction of the drive roller 122, after a preset period of time so as to reverse the rotational direction of the main body section 20 relative to the lower body section 22. In this example, the direction of the motor 118 is reversed every 3 to 5 seconds so that the main body section 20 oscillates relative to the lower body section 22 about an angle in the range from 60 to 120°. The user may deactivate, and subsequently re-activate, the oscillation mechanism 116 at will by repressing the second button 26 of the user interface.

Claims

CLAIMS1. A fan assembly for creating an air current, the fan assembly comprising: a body comprising a first section, a second section connected to the first section, the first section being moveable relative to the second section, and an air inlet; an air outlet moveable with the first section of the body; means for creating an air flow between the air inlet and the air outlet; and an oscillation mechanism for oscillating the first section of the body relative to the second section of the body; wherein the oscillation mechanism comprises a bi-directional motor located within the second section of the body, a friction drive member connected to the motor and a driven member connected to the first section of the body and which is driven by the drive member by means of friction therebetween..
2. A fan assembly as claimed in claim 1, wherein the oscillation mechanism comprises an idler for engaging the driven member.
3. A fan assembly as claimed in claim 2, wherein the idler is located diametrically opposite to the drive member.
4. A fan assembly as claimed in any of the preceding claims, wherein the driven member extends about the axis of oscillation of the first section of the body.
5. A fan assembly as claimed in any of the preceding claims, wherein the driven member is annular.
6. A fan assembly as claimed in any of the preceding claims, wherein the first section of the body comprises a shaft extending into the second section of the body, the second section of the body comprising a sleeve for receiving the shaft.
7. A fan assembly as claimed in claim 6, wherein the shaft is rotatably supported within the sleeve by at least one bearing.
8. A fan assembly as claimed in any of the preceding claims, wherein the first section of the body comprises said means for creating an air flow between the air inlet and the air outlet.
9. A fan assembly as claimed in any of the preceding claims, comprising a casing connected to the first section of the body, the casing comprising said air outlet.
10. A fan assembly as claimed in claim 9, wherein the casing comprises an opening through which air from outside the fan assembly is drawn by the air flow emitted from the air outlet.
11. A fan assembly substantially as herein described with reference to the accompanying drawings.