WO2017163068A1

WO2017163068A1 - Attachment for a handheld appliance

Info

Publication number: WO2017163068A1
Application number: PCT/GB2017/050810
Authority: WO
Inventors: Robert Coulton; Alasdair MACLAINE; Stephen Courtney
Original assignee: Dyson Technology Limited
Priority date: 2016-03-24
Filing date: 2017-03-22
Publication date: 2017-09-28
Also published as: CN108778043A

Abstract

An attachment for a hair styling apparatus comprising a body having a fluid inlet and a fluid outlet, wherein the fluid outlet comprises at least one slot formed by an overlap of an inner wall and an outer wall of the attachment. A fluid entry at a first end of the overlap is greater than a fluid exit at a second end of the overlap, and a high pressure fluid flow enters the attachment at the fluid inlet and exits through the at least one slot.

Description

ATTACHMENT FOR A HANDHELD APPLIANCE

FIELD OF THE INVENTION The present invention relates to an attachment for a handheld appliance, in particular a hair care appliance such as a hot air styling device.

BACKGROUND OF THE INVENTION In a conventional hot air styling device, air is drawn into an inlet by a fan unit and directed towards the hair by an attachment or head. Depending on the style desired, the air may or may not be heated. The attachment often includes bristles onto which hair is wrapped and held for styling. The air is generally blown out of the attachment normal to the longitudinal surface of the attachment.

SUMMARY OF THE INVENTION

The present invention provides an attachment for a hair styling apparatus, the attachment comprising a body having an inner wall and an outer wall, a fluid inlet and a fluid outlet, wherein the fluid outlet comprises at least one slot formed by an overlap of the inner wall and the outer wall, and said at least one slot has a fluid entry at a first end of the overlap and a fluid exit at a second end of the overlap, wherein the fluid entry has a greater width than the fluid exit. Preferably, the inner wall is an arc and the outer wall is an arc.

In a preferred embodiment, at least one of the inner wall and the outer wall are movable.

Preferably, the inner wall and the outer wall are movable such that the fluid outlet is closed. In a preferred embodiment, the inner wall comprises an outer surface adjacent to the at least one slot, and the outer wall comprises an inner surface adjacent to the at least one slot, and the outer surface of the inner wall has a smooth, rounded profile at the first end of the overlap.

In a further preferred embodiment, the inner surface of the outer wall has a substantially right-angled profile at the second end of the overlap.

The fluid entry preferably has a width three times greater than the fluid exit.

Alternatively, the fluid entry preferably has a width two times greater than the fluid exit.

In a preferred embodiment, the inner wall has a bulbous form extending away from the slot at the first end of the overlap.

In an alternative embodiment, the inner wall has an elongate form and substantially regular thickness. Advantageously, turbulent airflow is minimized within the attachment and consequently the audible volume of the hot air styling device with attachment is reduced in use.

Preferably, a fluid flow pressure at the fluid inlet is within the range 3 kPa to 4 kPa. Advantageously, the greater the airflow through the slot the greater the duration of attachment of the airflow to the outer surface of the inner vane. BRIEF DESCRIPTION OF THE DRAWINGS

Preferred features 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 cross-sectional view of a fluid outlet;

Figure 2 is a perspective view of a first attachment; Figure 3 is a transverse cross-sectional view of the first attachment; Figure 4 is a perspective view of a second attachment; Figure 5 is a transverse cross-sectional view of the second attachment;

Figure 6 is a cross-sectional view of an alternative embodiment of a fluid outlet; Figure 7a is a perspective view of an alternative embodiment of the first attachment;

Figure 7b is a perspective view of a further alternative embodiment of the first attachment;

Figure 8 is a side view of an example of a hot air styling device to which the attachment may be connected.

DETAILED DESCRIPTION OF THE INVENTION

A cross-sectional view of a fluid outlet is shown in Figure 1. The fluid outlet 10 is an elongate slot formed between an inner vane 12 and an outer vane 14 which are overlapping. A slot entry 16 is defined as the initial point at which the inner vane 12 and the outer vane 14 overlap. A slot exit 18 is defined as the final point at which the inner vane 12 and the outer vane 14 overlap. The slot length is defined as the length of overlap of the inner vane 12 and outer vane 14. A concave inner profile of the outer vane 14 and a convex outer profile of the inner vane 12 are both smooth and gradually curving, in a similar orientation. The outer vane is angled towards the inner vane such that the width of the slot exit 18 is less than the slot entry 16.

The profile of the distal end 20 of the outer vane comprises an approximate right-angle adjacent the slot, with a smooth curving surface leading to the outer surface 22 of the outer vane. The profile of the leading edge 24 of the inner vane is a smooth curved surface leading to the inner surface 26 of the inner vane 12.

In use, the fluid flow 28 passing through the slot 10 is moving from a duct into an ambient environment. Fluid flow 28 passing through the slot 10 is directed by the inner vane 12 and outer vane 14 to form a high pressure and high velocity fluid jet 30. The fluid jet 30 emitted from the slot exit 18 is tangential to the outer surface 32 of the inner vane 12 and is attached to the convex outer surface 32 of the inner vane 12 as a consequence of the Coanda effect (which is the tendency of a fluid jet to remain attached to a convex surface). Ideally, this fluid flow attachment occurs for the maximum duration possible.

To maximize the fluid jet attachment duration, the width of the slot exit 18 is less than the slot entry 16. The profile of a distal end 20 of the outer vane 14 and the profile of a leading edge 24 of the inner vane 12 as illustrated in Figure 1 function to further maximize the fluid flow attachment duration. Where the inner vane entry profile has a bulbous form 34 extending to the inner surface 26 of the inner vane 12, the airflow 28 has a greater area for initial airflow attachment. However, where the inner vane entry profile has a narrow form extending to the inner surface 26 of the inner vane 12, the airflow 28 has a reduced area for initial airflow attachment but the airflow inlet from the hot air styling device has a minimized volume of airflow barriers within the cylinder prior to exiting the slot and therefore, airflow pressure is not mitigated by the volume of airflow barriers within the cylinder.

A first attachment 36, as illustrated in Figure 2, is essentially cylindrical and extends longitudinally from a fluid inlet end 38 to a distal end 40. Elongate vanes 42 extend from the fluid inlet end 38 to the distal end 40, and elongate slots 46 disposed between adjacent vanes 42 comprise the fluid outlet for this first attachment 36. The fluid inlet 38 is generally circular in shape, to enable an air-tight connection with a generally circular outlet end of a hot air styling device. The distal end 40 of the attachment comprises a cool tip 48. A transverse cross-sectional view through the first attachment is shown in Figure 3. Each of the six vanes has an arc form and is positioned to overlap with the adjacent vane 42. The features of each overlapping section 44 are comparable with those illustrated in Figure 1. It is shown in Figure 3 that the distal end of each inner vane 12 forms an outer vane 14 at the adjacent slot.

The angle of attachment, Θ, is defined as the angle between the outer surface 32 of the inner vane 12 and the tangential direction of fluid flow jet 30 emitted from the slot exit 18.

In use, the fluid inlet receives an airflow from an airflow outlet end of a hot air styling device or similar device. Fluid flow exits each slot 10 tangentially to the outer surface 32 of the inner vane 12. As described in relation to Figure 1, the fluid jet 30 is attracted to the outer surface 32 of the inner vane 12. As fluid jet 30 attached to the outer surface of the inner vane reaches the distal end of that vane, it is drawn into the fluid jet emitted from the adjacent slot by the Coanda effect. Consequently, a continuous fluid flow path is formed around the circumference of the first attachment 36. Therefore, lightweight objects, such as a tress of hair, introduced into the area around the attachment are influenced by the fluid flow path to wrap around the cylindrical surface of the first attachment 36.

The second attachment 46, as illustrated in Figure 4 and Figure 5, is a broad duct surrounded by a casing 48 extending longitudinally from a fluid inlet end 50 to a distal end 52. Two elongate, pivoted, moveable members 53, 54 form sections of the casing 48 and extend approximately from the fluid inlet end 50 to the distal end 52, and elongate slots formed between the casing 48 and the moveable members 53, 54 comprise the fluid outlets for this second attachment 46. The moveable members 53, 54 pivot relative to the casing 48 on a longitudinal axis such that when a first slot 56 along a first longitudinal side 58 of a first moveable member 53 is fully open, then a second slot 60 along a second longitudinal side 62 of said moveable member 53 is fully closed. The fluid inlet 50 is generally circular in shape, to enable an air-tight connection with a generally circular outlet end of a hot air styling device.

With reference to Figure 5, an outer surface of each of the moveable members has an arc form and an inner surface of the casing adjacent the slot has an arc form. When the first moveable member 53 is pivoted such that the first slot 56 is fully open, then an overlap is formed between the outer surface 64 of the first moveable member 53 and an inner surface 66 of the casing. The skilled person will appreciate that the features of each overlap are comparable with those illustrated in Figure 1.

In use, the fluid inlet 50 receives an airflow from an airflow outlet end of a hot air styling device or similar device. A fluid flow exits a first open slot 56 tangentially to the outer surface 64 of the first moveable member 53. As also described in relation to Figure 1, a fluid jet is attracted to the outer surface 64 of the first moveable member 53. As the fluid jet attached to the outer surface 64 of the first moveable member 53 reaches the second longitudinal side 62 of said moveable member 53, it is drawn into the airflow emitted from an adjacent slot 68. Consequently, a continuous fluid flow path is formed across the upper outer surfaces of the second attachment 46. Therefore, lightweight objects, such as a tress of hair, introduced into the area around the second attachment are influenced by the fluid flow path to wrap over the upper outer surface of the second attachment.

A cross-sectional view of an alternative fluid outlet 70 is shown in Figure 6. The fluid outlet comprises two slots. A first slot is formed between an inner vane 72 and an outer vane 74, which are overlapping. A second slot is formed through the inner vane 72. An inner surface 78 of the outer vane 74 and an outer surface 84 of the inner vane 72 have a smooth, convex profile. The distal end 86 of the outer vane 74 is angled towards the inner vane 72 such that the width of the slot exit 88 is less than the slot entry 90. In use, fluid flow exiting the first slot is directed by the inner vane 72 and middle vane emitted from the first slot exit 88 is tangential to the outer surface 84 of the inner vane 72 and is attached to the convex outer surface 84 of the inner vane 72. As the first fluid jet 96 passes over the outer surface 84 of the inner vane 72 it gradually loses energy and therefore, also velocity. Consequently, the first fluid jet 96 has reduced attachment to the inner vane. A second fluid jet 98 emitted from the second slot combines with the first fluid jet 96 and therefore, the energy of the first fluid jet is increased. Consequently, the velocity of the combined fluid jet increases and the attachment of the combined fluid jet to the outer surface 84 of the inner vane 72 is enhanced. Figure 7a and figure 7b illustrate alternative embodiments of the cylindrical attachment of Figure 2 which similarly function to direct the exiting airflow over the surface of the attachment.

Figure 7a shows a cylinder arrangement 102 formed of a single tube having angled rectangular apertures 104 which extend from an internal surface of the tube through to the external surface. Figure 8b shows a cylinder arrangement 106 formed of a single tube having oval or circular angled apertures 108 which extend from an internal surface of the tube through to the external surface. The skilled person will appreciate that the internal form of the angled apertures 104, 108 is comparable to the angled slot arrangements described with respect to Figure 3.

Figure 8 shows an example of a hot air styling device 110 to which any one of the attachments may be connected. The hot air styling device 110 comprises a generally tubular handle 112 having an air inlet 114 and an air outlet 116 at opposing ends. At the air inlet end 114 of the handle, an array of apertures extending around and partially along the handle 112, provides an air inlet. A fan unit within the handle comprises a fan and a motor. In use, the motor drives the fan and air is drawn in through the air inlet, along an air flow path which extends through the length of the handle. The airflow is optionally heated by a heater before exiting the hot air styling device at the air outlet. Airflow emitted from the hot air styling device and entering the attachment is a relatively high pressure airflow of approximately 3.5kPa. Airflow in the range of 2kPa to 6kPa would provide a beneficial result. Such controlled high pressure flow is important for the effective styling of the hair of the user. The attachments described may be used with a fluid flow rate of approximately 5 litres/second to 35 litres/second. It is observed that a high flow rate alone, is not beneficial for styling the hair of the user.

It is observed that where air pressure in a duct is too great, then the flow exiting the slot is neither perpendicular to the slot nor evenly distributed along the slot. For example, for a duct having a diameter of 50mm and a length of 150mm, then an airflow pressure of 300Pa would a perpendicular, even flow.

Claims

1. An attachment for a hair styling apparatus comprising a body having;

an inner wall and an outer wall,

a fluid inlet and a fluid outlet, wherein the fluid outlet comprises at least one slot formed by an overlap of the inner wall and the outer wall, and

said at least one slot has a fluid entry at a first end of the overlap and a fluid exit at a second end of the overlap, wherein

the fluid entry has a greater width than the fluid exit.

2. An attachment according to claim 1, wherein the inner wall is an arc and the outer wall is an arc.

3. An attachment according to claim 1 or claim 2, wherein at least one of the inner wall and the outer wall are movable.

4. An attachment according to claim 3, wherein the inner wall and the outer wall are movable such that the fluid outlet is closed.

5. An attachment according to claim 1, wherein the inner wall comprises an outer surface adjacent to the at least one slot, and the outer wall comprises an inner surface adjacent to the at least one slot, and the outer surface of the inner wall has a smooth, rounded profile at the first end of the overlap.

6. An attachment according to claim 5, wherein the inner surface of the outer wall has a substantially right-angled profile at the second end of the overlap.

7. An attachment according to claim 1, wherein the fluid entry has a width three times greater than the fluid exit.

8. An attachment according to claim 1, wherein the fluid entry has a width two times greater than the fluid exit.

9. An attachment according to claim 5, wherein the inner wall has a bulbous form extending away from the slot at the first end of the overlap.

10. An attachment according to claim 5, wherein the inner wall has an elongate form and substantially regular thickness.

11. An attachment according to claim 1, wherein a fluid flow pressure at the fluid inlet is within the range 3 kPa to 4 kPa.