Fan assembly

Abstract

A fan assembly includes a base and a body mounted on the base for movement relative thereto between an untilted position and a tilted position. The fan assembly also includes an air outlet and an interior passage for conveying air to the air outlet, and which extends about an opening through which air from outside the fan assembly is drawn by air emitted from the air outlet. A brake and a stationary rail are disposed on the upper surface of the base, and a rail is connected to the lower surface of the body and located between the brake and the stationary rail. The brake is urged by a spring or other resilient member towards the stationary rail to urge the rail of the body against the stationary rail to maintain the body in a tilted position by means of friction between the rails.

Claims

1. A fan assembly comprising a base; a body mounted on the base for movement relative thereto between an untilted position and a tilted position, the body comprising at least one air inlet, an impeller and a motor for driving the impeller to draw an air flow through said at least one air inlet; at least one air outlet; an interior passage for conveying air to said at least one air outlet, the interior passage extending about an opening through which air from outside the fan assembly is drawn by air emitted from said at least one air outlet; a brake connected to the base for movement relative thereto; a stop member connected to the base; a section of the body being disposed between the brake and the stop member; and a resilient member for urging the brake towards the stop member to urge the section of the body against the stop member to maintain the body in a tilted position relative to the base by friction between the section of the body and the stop member, wherein the stop member comprises a first rail and the section of the body comprises a second rail extending substantially parallel to the first rail, the second rail comprising a recess on a first side surface of the second rail that faces the brake such that when part of the brake is moved into the recess an indication is provided that the body has been moved toward the untilted position.

2. The fan assembly of claim 1, wherein the brake is mounted on the upper surface of the base.

3. The fan assembly of claim 2, wherein the base comprises a plurality of brake guide rails connected to the upper surface of the base, and wherein the brake is secured to the brake guide rails for sliding movement along the brake guide rails.

4. The fan assembly of claim 2, wherein the stop member is connected to the upper surface of the base.

5. The fan assembly of claim 1, wherein the second rail comprises a second side surface located opposite to the first side surface, and wherein the brake is configured to engage the first side surface and the stop member is configured to engage the second side surface.

6. The fan assembly of claim 1, wherein each rail is curved.

7. The fan assembly of claim 1, wherein each rail extends in a direction which is parallel to the direction of movement of the body relative to the base.

8. The fan assembly of claim 1, wherein the brake is moveable relative to the base in a direction which is substantially orthogonal to the direction of movement of the body relative to the base.

9. The fan assembly of claim 1, wherein the brake is moveable relative to the base in a direction which is substantially orthogonal to an axis of rotation of the impeller when the body is in the untilted position.

10. The fan assembly of claim 1, comprising a seat connected to the base, and wherein the resilient member is located between the seat and the brake.

11. The fan assembly of claim 1, wherein the section of the body forms part of a plate connected to a lower surface of the body.

12. The fan assembly of claim 1, wherein the upper surface of the base is concave in shape, and wherein the lower surface of the body is convex in shape.

13. The fan assembly of claim 1, comprising a plurality of pairs of interlocking members for retaining the body on the base, wherein each pair of interlocking members comprises a first interlocking member located on the base and a second interlocking member located on the body and which is retained by the first interlocking member.

14. The fan assembly of claim 1, wherein movement of the brake into the recess as the body is moved towards the untilted position provides a variation in the force required to move the body relative to the base.

15. The fan assembly of claim 14, wherein the variation in the force required to move the body is a reduction in the force required to move the body relative to the base.

16. A stand for a fan assembly, the stand comprising a base; a body mounted on the base for movement relative thereto between an untilted position and a tilted position, the body comprising at least one air inlet, an impeller, a motor for driving the impeller to draw an air flow through said at least one air inlet, and an air outlet; a brake connected to the base for movement relative thereto; a stop member connected to the base; a section of the body being disposed between the brake and the stop member; and a resilient member for urging the brake towards the stop member to urge the section of the body against the stop member to maintain the body in a tilted position relative to the base by friction between the section of the body and the stop member, wherein the stop member comprises a first rail and the section of the body comprises a second rail extending substantially parallel to the first rail, the second rail comprising a recess on a first side surface of the second rail that faces the brake such that when part of the brake is moved into the recess an indication is provided that the body has been moved toward the untilted position.

17. The stand of claim 16, wherein the brake is mounted on the upper surface of the base.

18. The stand of claim 17, wherein the base comprises a plurality of brake guide rails connected to the upper surface of the base, and wherein the brake is secured to the brake guide rails for sliding movement along the brake guide rails.

19. The stand of claim 16, wherein the stop member is connected to the upper surface of the base.

20. The stand of claim 16, wherein the second rail comprises a second side surface located opposite to the first side surface, and wherein the brake is configured to engage the first side surface and the stop member is configured to engage the second side surface.

Description

BRIEF DESCRIPTION OF THE INVENTION

(1) An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 is a front perspective view of a fan assembly;

(3) FIG. 2 is a front sectional view through the body and the nozzle of the fan assembly;

(4) FIG. 3 is a left side sectional view through the body and the nozzle of the fan assembly;

(5) FIG. 4(a) is a left perspective view of the base of the fan assembly, and FIG. 4(b) is a right perspective view of the base of the fan assembly;

(6) FIG. 5 is a bottom perspective view of the body of the fan assembly;

(7) FIG. 6(a) is a bottom perspective view of a tilt plate of the body, and FIG. 6(b) is a close-up of region A identified in FIG. 6(a);

(8) FIG. 7 is a top view of the base of the fan assembly, with the tilt plate attached to the base and in an untilted position relative to the base;

(9) FIG. 8(a) is a front sectional view of the base and the tilt plate taken along line Y-Y in FIG. 7, and FIG. 8(b) is a close-up of region B identified in FIG. 8(a);

(10) FIG. 9 is a top sectional view taken along line Z-Z in FIG. 8(a);

(11) FIG. 10 is a similar view to FIG. 9, but with the tilt plate in a tilted position relative to the base; and

(12) FIG. 11(a) is a side view of the fan assembly with the body in a first fully tilted position relative to the base, FIG. 11(b) is a side view of the fan assembly with the body in an untilted position relative to the base, and FIG. 11(c) is a side view of the fan assembly with the body in a second fully tilted position relative to the base.

DETAILED DESCRIPTION OF THE INVENTION

(13) FIG. 1 is an external view of a fan assembly 10. The fan assembly 10 comprises a body 12 having an air inlet 14 in the form of a plurality of apertures formed in the outer casing 16 of the body 12, and through which a primary air flow is drawn into the body 12 from the external environment. An annular nozzle 18 having an air outlet 20 for emitting the primary air flow from the fan assembly 10 is connected to the upper end of the body 12. The body 12 is mounted on a base 22 so as to allow the body 12 to tilt relative to the base 22. The base 22 comprises a user interface for allowing a user to control the operation of the fan assembly 10. In this embodiment, the user interface comprises a plurality of user-operable buttons 23, 24 and a user-operable dial 26.

(14) The nozzle 18 has an annular shape. With reference also to FIGS. 2 and 3, the nozzle 18 comprises an outer wall 28 extending about an annular inner wall 30. In this example, each of the walls 28, 30 is formed from a separate component. Each of the walls 28, 30 has a front end and a rear end. The rear end of the outer wall 28 curves inwardly towards the rear end of the inner wall 30 to define a rear end of the nozzle 18. The front end of the inner wall 30 is folded outwardly towards the front end of the outer wall 28 to define a front end of the nozzle 18. The front end of the outer wall 28 is inserted into a slot located at the front end of the inner wall 30, and is connected to the inner wall 30 using an adhesive introduced to the slot.

(15) The inner wall 30 extends about an axis, or longitudinal axis, X to define a bore, or opening, 32 of the nozzle 18. The bore 32 has a generally circular cross-section which varies in diameter along the axis X from the rear end of the nozzle 18 to the front end of the nozzle 18.

(16) The inner wall 30 is shaped so that the external surface of the inner wall 30, that is, the surface that defines the bore 32, has a number of sections. The external surface of the inner wall 30 has a convex rear section 34, an outwardly flared frusto-conical front section 36 and a cylindrical section 38 located between the rear section 34 and the front section 36.

(17) The outer wall 28 comprises a base 40 which is connected to an open upper end of the body 12, and which has an open lower end which provides an air inlet for receiving the primary air flow from the body 12. The majority of the outer wall 28 is generally cylindrical shape. The outer wall 28 extends about a central axis, or longitudinal axis, Y which is parallel to, but spaced from, the axis X. In other words, the outer wall 28 and the inner wall 30 are eccentric. In this example, the axis X is located above the axis Y, with each of the axes X, Y being located in a plane which extends vertically through the centre of the fan assembly 10.

(18) The rear end of the outer wall 28 is shaped to overlap the rear end of the inner wall 30 to define the air outlet 20 of the nozzle 18 between the inner surface of the outer wall 28 and the outer surface of the inner wall 30. The air outlet 20 is in the form of a generally circular slot centred on, and extending about, the axis X. The width of the slot is preferably substantially constant about the axis X, and is in the range from 0.5 to 5 mm. The overlapping portions of the outer wall 28 and the inner wall 30 are substantially parallel, and are arranged to direct air over the convex rear section 34 of the inner wall 30, which provides a Coanda surface of the nozzle 18. A series of angularly spaced spacers may be provided on one of the facing surfaces of the overlapping portions of the outer wall 28 and the inner wall 30 to engage the other facing surface to maintain a regular spacing between these facing surfaces.

(19) The outer wall 28 and the inner wall 30 define an interior passage 42 for conveying air to the air outlet 20. The interior passage 42 extends about the bore 32 of the nozzle 18. In view of the eccentricity of the walls 28, 30 of the nozzle 18, the cross-sectional area of the interior passage 42 varies about the bore 32. The interior passage 42 may be considered to comprise first and second curved sections 44, 46 which each extend in opposite angular directions about the bore 32. Each curved section 44, 46 of the interior passage 42 has a cross-sectional area which decreases in size about the bore 32.

(20) The body 12 and the base 22 are preferably formed from plastics material. The body 12 and the base 22 preferably have substantially the same external diameter so that the external surface of the body 12 is substantially flush with the external surface of the base 22 when the body 12 is in an untilted position relative to the base 22.

(21) The body 12 comprises the air inlet 14 through which the primary air flow enters the fan assembly 10. In this embodiment the air inlet 14 comprises an array of apertures formed in the section of the outer casing 16 of the body 12. Alternatively, the air inlet 14 may comprise one or more grilles or meshes mounted within windows formed in the outer casing 16. The body 12 is open at the upper end (as illustrated) for connection to the base 40 of the nozzle 18, and to allow the primary air flow to be conveyed from the body 12 to the nozzle 18.

(22) The body 12 comprises a duct 50 having a first end defining an air inlet 52 of the duct 50 and a second end located opposite to the first end and defining an air outlet 54 of the duct 50. The duct 50 is aligned within the body 12 so that the longitudinal axis of the duct 50 is collinear with the longitudinal axis of the body 12, and so that the air inlet 52 is located beneath the air outlet 54.

(23) The duct 50 extends about an impeller 56 for drawing the primary air flow into the body 12 of the fan assembly 10. The impeller 56 is a mixed flow impeller. The impeller 56 comprises a generally conical hub, a plurality of impeller blades connected to the hub, and a generally frusto-conical shroud connected to the blades so as to surround the hub and the blades. The blades are preferably integral with the hub, which is preferably formed from plastics material.

(24) The impeller 56 is connected to a rotary shaft 58 extending outwardly from a motor 60 for driving the impeller 56 to rotate about a rotational axis Z. The rotational axis Z is collinear with the longitudinal axis of the duct 50 and orthogonal to the axes X, Y. In this embodiment, the motor 60 is a DC brushless motor having a speed which is variable in response to user manipulation of the dial 26. The maximum speed of the motor 60 is preferably in the range from 5,000 to 10,000 rpm. The motor 60 is housed within a motor housing. The outer wall of the duct 50 surrounds the motor housing, which provides an inner wall of the duct 50. The walls of the duct 50 thus define an annular air flow path which extends through the duct 50. The motor housing comprises a lower section 62 which supports the motor 60, and an upper section 64 connected to the lower section 62. The shaft 58 protrudes through an aperture formed in the lower section 62 of the motor housing to allow the impeller 56 to be connected to the shaft 58. The motor 60 is inserted into the lower section 66 of the motor housing before the upper section 68 is connected to the lower section 66.

(25) The lower section 62 of the motor housing is generally frusto-conical in shape, and tapers inwardly in a direction extending towards the air inlet 52 of the duct 50. The hub of the impeller 56 has a conical inner surface which has a similar shape to that of a contiguous part of the outer surface of the lower section 62 of the motor housing.

(26) The upper section 64 of the motor housing is generally frusto-conical in shape, and tapers inwardly towards the air outlet 54 of the duct 50. An annular diffuser 66 is located between the outer wall of the duct 50 and the upper section 64 of the motor housing. The diffuser 66 comprises a plurality of blades 68 for guiding the air flow towards the air outlet 54 of the duct 50. The shape of the blades 68 is such that the air flow is also straightened as it passes through the diffuser 66. A cable for conveying electrical power to the motor 60 passes through the outer wall of the duct 50, the diffuser 66 and the upper section 64 of the motor housing. The upper section 64 of the motor housing is perforated, and the inner surface of the upper section 64 of the motor housing is lined with noise absorbing material 70, preferably an acoustic foam material, to suppress broadband noise generated during operation of the fan assembly 10.

(27) The impeller housing 68 is mounted on an annular seat 72 located within the body 12. The seat 72 extends radially inwardly from the inner surface of the outer casing 16 so that an upper surface of the seat 72 is substantially orthogonal to the rotational axis Z of the impeller 56. An annular seal 74 is located between the impeller housing 68 and the seat 72. The annular seal 74 is preferably a foam annular seal, and is preferably formed from a closed cell foam material. The annular seal 74 has a lower surface which is in sealing engagement with the upper surface of the seat 72, and an upper surface which is in sealing engagement with the impeller housing 68. A plurality of resilient supports are also provided between the impeller housing 68 and the seat 72 for bearing part of the weight of the duct 50, the impeller 56, the motor 60, and the motor housing. The resilient supports are equally spaced from, and equally spaced about, the longitudinal axis of the body 12. The seat 72 comprises an aperture to enable the cable (not shown) to pass to the motor 60. The annular seal 74 is shaped to define a recess to accommodate part of the cable. One or more grommets or other sealing members may be provided about the cable to inhibit the leakage of air through the aperture, and between the recess and the internal surface of the outer casing 16.

(28) A guide member 76 is provided about the inlet section 66 and the lower end of the impeller housing 68 for guiding the air flow entering the body 12 towards the air inlet 52 of the duct 50. The guide member 76 is generally frusto-conical in shape, and tapers inwardly towards the base 56 of the body 12. The guide member 76 defines in part a tortuous air flow path between the air inlet 14 of the body 12 and the air inlet 52 of the duct 50, and so serves to block any direct path for noise passing from the air inlet 52 of the duct 50 towards the air inlet 14 of the body 12. The guide member 76 depends from an annular rib extending about the impeller housing 68. The outer periphery of the rib may be connected to the inner surface of the body 12, for example using an adhesive. The outer surface of the guide member 76 which is exposed to the air flow passing through the body 12 is lined with sound-absorbing material 78.

(29) The body 12 comprises a noise suppression cavity 80 located beneath the air inlet 52 of the duct 50. The cavity 80 is also tuned to the wavelength of the rotational tone of the impeller 56. The cavity 80 has an inlet 82 which is located beneath the air inlet 52 of the duct 50, and which is preferably concentric with the air inlet 52 of the duct 50. A lower wall of the cavity 80 is defined by a curved base 84 of the outer casing 16 of the body 12. The inlet 82 and an upper wall of the cavity 80 are defined by an annular plate 86 which is connected to the upper peripheral portion of the base 84.

(30) To reduce the level of broadband noise emitted from the fan assembly 10, an annular sound absorbing member 88 is preferably located between the duct 50 and the cavity 80. The annular sound absorbing member 88 is concentric with the inlet 82 of the cavity 80, and has an outer periphery which is in contact with the inner surface of the outer casing 16. The inner surface of the outer casing 16 is partially lined with sound absorbing material. For example, a sheet of sound-absorbing material 90 may be located immediately downstream of the air inlet 14 to reduce the level of broadband noise emitted through the air inlet 14 of the body 12.

(31) As mentioned above, the body 12 is mounted on a base 22. With reference to FIGS. 4(a) and 4(b), the base 22 comprises an upper base member 100 mounted on a lower base member 102. The upper base member 100 comprises the aforementioned user interface and a control circuit for controlling various functions of the fan assembly 10 in response to operation of the user interface. The upper base member 100 also houses a mechanism for oscillating the upper base member 100 relative to the lower base member 102. The oscillation mechanism is identified generally at 104 in FIG. 8(a). The operation of the oscillation mechanism 104 is controlled by the control circuit in response to the user's depression of the button 24 of the user interface. The range of each oscillation cycle of the upper base member 100 relative to the lower base member 102 is preferably between 60° and 120°, and the oscillation mechanism is arranged to perform around 3 to 5 oscillation cycles per minute. A mains power cable (not shown) for supplying electrical power to the fan assembly 10 extends through an aperture formed in the lower base member 102.

(32) The body 12 is mounted on the base 22 so as to be moveable relative to the base 22 between a first fully tilted position, as illustrated in FIG. 11(a) and a second fully tilted position, as illustrated in FIG. 11(c). The axes X, Y are preferably inclined by an angle of around 10° as the main body is moved from an untilted position, as illustrated in FIG. 11(b) to one of the two fully tilted positions. The outer surfaces of the body 12 and the upper base member 100 are shaped so that adjoining portions of these outer surfaces are substantially flush when the body 12 is in the untilted position.

(33) The body 12 is mounted on the base 22 so that the body 12 is slidable relative to the base 22 as it moves to or from a tilted position. Referring again to FIGS. 4(a) and 4(b), the upper base member 100 comprises a curved upper surface 106. The curved upper surface 106 is concave in shape, and may be described as generally saddle-shaped. An aperture 108 is formed in the upper surface 106 for receiving an electrical cable extending between the motor 60 and the control circuit.

(34) The upper base member 100 comprises a plurality of first interlocking members which each co-operate with a respective second interlocking member located on the body 12 to retain the body 12 on the upper base member 100. The first interlocking members also serve to guide the movement of the body 12 relative to the upper base member 100 so that there is substantially no twisting or rotation of the body 12 relative to the upper base member 100 as it is moved from or to a tilted position. Each of the first interlocking members extends in the direction of movement of the body 12 relative to the base 22. In this embodiment, the upper base member 100 comprises two, relatively short, outer interlocking members 110, and a single, relatively long inner interlocking member 112 located between the outer interlocking members 110. Each of the outer interlocking members 110 has a cross-section in the form of an inverted L-shape. Each of the outer interlocking members 110 comprises a wall 114 which is connected to, and upstanding from, the upper surface 106 of the upper base member 100, and a curved flange 116 which connected to, and orthogonal to, the upper end of the wall 114. The inner interlocking member 112 also has a cross-section in the form of an inverted L-shape. The inner interlocking member 112 comprises a wall 118 which is connected to, and upstanding from, the upper surface 106 of the upper base member 100, and a curved flange 120 which connected to, and orthogonal to, the upper end of the wall 118.

(35) The body 12 comprises a substantially cylindrical outer casing 16 having an annular lower end 122 and a curved base 84 which is spaced from the lower end 122 of the outer casing 16 to define a recess. The lower surface of the base 84 is convex in shape, and may be described generally as having an inverted saddle-shape. An aperture 124 is formed in the base 84 for allowing the cable to extend into the body 12.

(36) As illustrated in FIG. 5, a convex tilt plate 126 is connected to the base 84 of the outer casing 16. The tilt plate 126 is located within the recess so that the casing 16 surrounds the outer periphery of the tilt plate 126. The tilt plate 126 has a curvature which is substantially the same as that of the base 84. The tilt plate 126 has a convex lower surface 128. The tilt plate 126 is illustrated in isolation from the outer casing 16 in FIGS. 6(a) and 6(b). The tilt plate 126 comprises a plurality of second interlocking members which are each retained by a respective first interlocking member of the upper base member 100 to connect the body 12 to the base 22. The tilt plate 126 comprises a plurality of parallel grooves which define a plurality of curved rails of the tilt plate 126. The grooves define a pair of outer rails 128 and a first inner rail 130, and these rails 128, 130 provide the second interlocking members of the body 12. Each of the outer rails 128 comprises a flange 132 which extends into a respective groove of the tilt plate 126, and which has a curvature which is substantially the same as the curvature of the flanges 116 of the upper base member 100. The first inner rail 130 also comprises a flange 134 which extends into a respective groove of the tilt plate 126, and which has a curvature which is substantially the same as the curvature of the flange 120 of the upper base member 100. An aperture (not shown) is formed in the first inner rail 130 for allowing the cable to pass through the tilt plate 126. The lower surface 128 of the tilt plate 126 comprises a plurality of parallel ridges 136 which extend in the direction of tilting movement of the body 12 relative to the base 22, and which engage the upper surface 106 of the upper base member 100 when the tilt plate 126 is slid on to the base 22. This reduces the area of contact between the lower surface 128 of the tilt plate 126 and the upper surface 106 of the upper base member 100, and so reduces frictional forces between the lower surface 128 of the tilt plate 126 and the upper surface 106 of the upper base member 100 as the body 12 is tilted relative to the base 22.

(37) To connect the body 12 to the upper base member 100, the tilt plate 126 is inverted from the orientation illustrated in FIG. 6(a). The cable extending through the aperture 124 of the outer casing 16 of the body 12 is fed through the apertures in the tilt plate 126 and the upper base member 100 respectively for subsequent connection to the control circuit within the base 22. The tilt plate 126 is then slid over the upper base member 100 so that the flange 132 of each outer rail 128 is located beneath a respective flange 116 of the upper base member 100, and so that the flange 134 of the first inner rail 130 is located beneath the flange 120 of the upper base member 100. FIG. 7 is an external view of the base 22 when the tilt plate 126 has been slid fully on to the base 22.

(38) With the tilt plate 126 positioned centrally on the upper base member 100, the body 12 is lowered on to the tilt plate 126 so that tilt plate 126 is housed within the recess of the outer casing of the body 12. The upper base member 100 and the body 12 are then inverted, and the body 12 is tilted relative to the base 22 to reveal a first plurality of apertures 140 located on the tilt plate 126. Each of these apertures 140 is aligned with a respective tubular protrusion 141 (one of which is shown in FIG. 3) on the base 84 of the outer casing 16 of the body 12. A self-tapping screw is screwed into each of the apertures 140 to enter the underlying protrusion 141, thereby partially connecting the tilt plate 126 to the body 12. The body 12 is then tilted in the reverse direction to reveal a second plurality of apertures 142 located on the tilt plate 126. Each of these apertures 142 is also aligned with a tubular protrusion 143 (one of which is shown in FIG. 3) on the base 84 of the outer casing 16 of the body 12. A self-tapping screw is screwed into each of the apertures 142 to enter the underlying protrusion 143 to complete the connection of the tilt plate 126 to the body 12. As the body 12 is tilted relative to the base 22, engagement between each of the flanges 116, 120 of the base 22 with a respective portion of the inner wall of the outer wall 16 which defines the recess in which the tilt plate 126 is located prevents the tilt plate 126 from sliding free from the base 22.

(39) The fan assembly 10 includes a mechanism for retaining the body 12 in a desired tilted position relative to the base 22. This mechanism will now be described with reference to FIGS. 4(a), 4(b), and 6(a) to 10.

(40) Referring first to FIGS. 4(a) and 4(b), the upper base member 100 comprises a brake 150 which is moveable relative to the upper base member 100. The brake 150 comprises a pair of side arms 152 which each extends over and partially about a respective guide rail 154 formed on the upper base member 100. The guide rails 154 are parallel, and extend in a direction which is orthogonal both to the walls 114, 118, and to the direction in which the body 12 moves relative to the base 22. The brake 150 is secured to the guide rails 154 in a snap-fit connection which allows the brake 150 to move along the guide rails 154 in a direction which is parallel to the guide rails 154. The brake 150 comprises a plurality of brake pads 156. The pads 156 may be secured to the brake 150, or they may be integral with the brake 150. The pads 156 are located on a surface of the brake 150 which faces a side surface 158 of a stop member 160. In this embodiment, the stop member 160 is in the form of a rail which is connected to, and is preferably integral with, the upper surface 106 of the upper base member 100. The stop member extends in a direction which is parallel to the walls 114, 118 of the upper base member 100. The brake 150 is urged towards the stop member 160 by a spring 162 or other resilient element. The spring 162 is located between the brake 150 and a seat 164 connected to, and preferably integral with, the upper surface 106 of the upper base member 100.

(41) With reference to FIGS. 8(a), 8(b) and FIGS. 9 and 10, as the tilt plate 126 is slid on to the upper base member 100 a section of the tilt plate 126 slides between the brake 150 and the stop member 160. In this embodiment, a second inner rail 166 of the tilt plate 126 slides between the brake 150 and the stop member 160. The second inner rail 166 also extends in the direction of the tilting movement of the body 12 relative to the base 22, and has a first side surface 168 and a second side surface 170 which is parallel to the first side surface 168. The pads 156 of the brake 150 engage the first side surface 168 of the second inner rail 166, which causes the second side surface 170 to be pushed against the side surface 158 of the stop member 160. FIG. 10 illustrates the relative positions of the base 22 and the tilt plate 126 when the body 12 is in a tilted position relative to the base 22. The spring constant of the spring 162 is selected such that the friction forces generated between the side surface 158 of the stop member 160 and the second side surface 170 of the second inner rail 166 as the brake 150 urges, under the force of the spring 162, these surfaces together is sufficient to hold the body 12 in a tilted position relative to the base 22 against the action of the weight of the body 12 and the nozzle 18 connected to the body 12.

(42) Returning to FIGS. 6(a) and 6(b), a recess 172 is provided on the first side surface 168 of the second inner rail 166. The recess 172 is shaped to accommodate at least the part of the brake pads 156 of the brake 150. In the tilted position of the tilt plate 126, and therefore the body 12, relative to the base 22 which is illustrated in FIG. 10, the brake pads 156 are spaced from the recess 172. As the tilt plate 126, and therefore the body 12, moves towards the untilted position illustrated in FIG. 9, the brake pads 156 slide along the first side surface 168 of the second inner rail 166. The decrease in the force required to move the body 12 relative to the base 22 as the brake pads 156 enter the recess 172 can allow the user to identify that the body 12 has been moved to its untilted position.

(43) To operate the fan assembly 10 the user presses button 23 of the user interface, in response to which the control circuit in the base 22 activates the motor 60 to rotate the impeller 56. The rotation of the impeller 56 causes a primary air flow to be drawn into the body 12 through the air inlet 14. The user may control the speed of the motor 60, and therefore the rate at which air is drawn into the body 12 through the air inlet 14, by manipulating the dial 26. The rotation of the impeller 56 causes a primary air flow to enter the body 12 through the air inlet 14, and to pass to the air inlet 52 of the duct 50. The air flow passes through the duct 50 and is guided by the shaped peripheral surface of the air outlet 54 of the duct 50 into the interior passage 42 of the nozzle 18. Within the interior passage 42, the primary air flow is divided into two air streams which pass in opposite angular directions around the bore 32 of the nozzle 18, each within a respective section 44, 46 of the interior passage 42. As the air streams pass through the interior passage 42, air is emitted through the air outlet 20. The emission of the primary air flow from the air outlet 20 causes a secondary air flow to be generated by the entrainment of air from the external environment, specifically from the region around the nozzle 18. This secondary air flow combines with the primary air flow to produce a combined, or total, air flow, or air current, projected forward from the nozzle 18.