Hair dryer

Abstract

A hair dryer (10) has a hand-held housing comprising an air inlet (12), an air outlet (14), a motor (1) between said air inlet (12) and said air outlet (14) to draw air in from said air inlet (12) and drive air out from said air outlet (14). A heating element (17) is located in said air flow between said air inlet (12) and said air outlet (14). The hair dryer (10) further comprises a filter on said air inlet (12). The filter comprises a metal filter plate (20) bearing a plurality of holes, wherein at least some of said holes have a maximum lateral dimension of less than 1.5 mm and wherein vertical walls of said holes through a thickness of said filter plate are substantially straight or at least partially concave.

Claims

1. A hair dryer having a hand-held housing comprising: an air inlet, an air outlet, a motor and impeller between the air inlet and the air outlet to draw air in from the air inlet and drive air out from the air outlet, a finger guard in the air inlet to prevent a user inserting a finger into the hair dryer; a heating element located between the air inlet and the air outlet, a filter on the air inlet, wherein the filter is a metal filter plate having an inner surface facing towards the motor and an outer surface facing away from the motor, the inner surface and the outer surface being parallel with each other and being separated by a thickness of the metal filter plate, wherein the metal filter plate comprises: a plurality of circular holes extending through the thickness of the metal filter plate between the outer surface and the inner surface of the metal filter plate, the plurality of circular holes aligned so as to form a plurality of spiral arms extending from a laterally central region of the filter, wherein at least some of the plurality of circular holes have a maximum lateral dimension of less than 1.5 mm, wherein a wall of each of the plurality of circular holes through the thickness of the metal filter plate is at least partially concave in the thickness direction, wherein the plurality of circular holes have radii that reduce with increasing radial distance from the laterally central region of the filter plate, the metal filter plate has an increasing proportion of hole to plate approaching the center of the metal filter plate to allow a higher velocity profile of air drawn into the hair dryer towards the laterally central region of the filter plate, and a plurality of close-packed hexagonal holes, wherein the hexagonal holes are dispersed in and around the plurality of spiral arms.

2. A hair dryer, as claimed in claim 1, wherein the metal filter plate is flat.

3. A hairdryer as claimed in claim 1, wherein the lateral dimension reduces by factor of at least 2.5.

4. A hair dryer as claimed in claim 1, wherein at least some of the plurality of circular holes have a maximum lateral dimension of less than 1 mm and wherein the thickness of the filter plate is less than 0.5 mm.

5. The hair dryer of claim 1, wherein the wall of each of the plurality of circular holes has a concave profile.

6. The hair dryer of claim 1, wherein the wall of each of the plurality of circular holes has a double concave profile that is symmetric about a midpoint of the hole wall.

7. A hair dryer as claimed in claim 1, wherein the wall of each of the plurality of circular holes comprises a pair of sections, a first concave section and a second substantially straight section.

8. A hair dryer as claimed in claim 1, wherein the plurality of circular holes are formed by acid spray etching.

9. A hair dryer as claimed in claim 1, further comprising a filter mount for mounting the metal filter plate, wherein the filter mount is user-detachable from the hair dryer, and wherein the metal filter plate is user-detachable from the filter mount.

10. The hair dryer of claim 1, wherein the metal filter plate further comprises a lug located along a perimeter of the metal filter plate, the lug sized to be received within a filter mount configured to attach to the housing proximate the air inlet.

11. A hair dryer as claimed in claim 1, wherein the heating element is located between the impeller and the air outlet, and wherein the impeller is located between the air inlet and the heating element and is configured to draw in air axially from the air inlet and to expel the air radially from the impeller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects of the invention will now be further described, by way of example only, with reference to the accompanying figures in which:

(2) FIG. 1 shows a side view a hair dryer according to an embodiment of the invention;

(3) FIG. 2 shows a cross sectional view of the hair dryer of FIG. 1;

(4) FIG. 3a shows an embodiment of a metal filter plate attached to the hair dryer of FIG. 1;

(5) FIG. 3b shows a cross sectional side view the metal filter plate of FIG. 3a;

(6) FIG. 3c shows a zoomed in view of a portion of the metal filter plate of FIG. 3a;

(7) FIG. 3d shows a zoomed in cross sectional side view of the portion of the metal filter plate of FIG. 3c;

(8) FIGS. 4a-4d show variations in the walls of holes of the filter plate of FIG. 2a;

(9) FIG. 5 shows a 3D view of the rear of the hair dryer of FIG. 1 showing the filter of FIG. 3a and a filter mount; and

(10) FIG. 6 shows the filter plate of FIG. 3a detaches from a filter mount.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(11) FIG. 1 shows a side view of a hair dryer 10 and FIG. 2 shows a cross sectional view of hair dryer 10 according to an embodiment of the invention. The hair dyer has an air inlet 12, an air outlet 14, a motor 16 located between the inlet 12 and outlet 14. The motor 16 powers an impeller 18 which draws in air axially from the inlet 12 and expels air radially from the impeller towards outlet 14. A heating element 17 is located between the motor and outlet to heat the air before it is expelled through the outlet. Attached to the handle 11 are controls 15 for turning the hair dryer on and off, controlling the rotational speed of the motor (and thereby controlling the flow rate of expelled air) and temperature of the expelled air.

(12) Coupled to the rear of the hair dryer, about the air inlet 12, a metal filter plate 20 is mounted in a filter mount 30. The metal filter plate 20 attaches to the filter mount 30, the filter mount then attaches to the rear of the hair dryer so that the air inlet 12 is covered by the filter plate 20. A finger guard 13 located at the air inlet ensures that a user is prevented from inserting a finger into the body of the hair dryer with the filter mount and plate removed.

(13) FIG. 3a shows the metal filter plate 20 that can be mounted on the air inlet of hair dryer 10. The filter plate 20 has smooth flat surfaces with an arrangement of holes through the filter to permit air to be drawn into the hair dryer whilst minimising dust, debris and hair being pulled into the hair dryer. The smooth surface also means that the filter plate is easy to clean. A portion 26 of the metal filter plate 20 is shown in more detail in FIG. 3c.

(14) FIG. 3b shows a cross sectional side view of the metal filter plate of FIG. 3a. In the embodiment of FIG. 3a-3d the filter plate is made from 0.3 mm stainless steel. It will be appreciated however that other variants are possible and the composition and thickness of the metal plate may vary.

(15) Locating lugs 22, 24 control the positioning of the filter plate when engaged to the filter mount 30 on the hair dryer. Corresponding receptors on the filter mount 30 ensure that the filter plate is arranged to sit in a prescribed position within the mount. This prevents the filter plate rotating unintentionally thereby ensuring the arrangement of holes on the filter plate is optimised. The filter plate 20 is removable from the mount for cleaning and optionally changing with another filter plate.

(16) The lateral dimension of some of the holes in the filter plate decreases with increasing radial distance from the centre of the filter plate as shown by holes 21a, 21b and 21c respectively. This provides a higher proportion of holes approaching the centre of the filter where the velocity profile of the drawn in air can be higher. In FIG. 3a for example, the holes are arranged into a spiral formation, with holes decreasing in size towards the outer edge of the filter plate. In the embodiment show, the laterally central region of the filter (which in the embodiment show aligns with the axis of the motor 16 and impeller 18 in FIG. 2) has minimal holes.

(17) Referring now to FIG. 3c, this shows a five times zoomed in view of a portion 26 of filter plate 20. FIG. 3c shows how some of the holes are formed as hexagonal holes 25 in the filter plate to permit a high density arrangement of holes. In the embodiment shown, the lateral dimension of these hexagonal holes 25 are approximately 1 mm (some less) and the holes are separated by a distance of approximately 0.25 mm. FIG. 3d shows a cross sectional side view of the metal filter plate portion of FIG. 3c.

(18) FIGS. 4a-4d shows cross sectional view of the sections of the metal filter plate 20 of FIG. 3a. FIGS. 4a-4d show variations on the walls of the holes 23a, 23b, 23c, 23d formed by spray acid etching a stainless steel sheet to form the filter plate. Holes 23a-23d for example show hole walls with concave sections. The spray acid etching may also leave a portion of walls of some holes substantially flat; others may have a section that is flat and a section concave. Spray acid etching from both sides of the sheet, for example, may result in a double concave surface topography such as shown by hole 23b. Very small holes are achievable with such a process with the embodiment herein shown having holes with lateral dimensions down to approximately 1 mm to ensure an adequate air flow (although smaller holes may be present if so desired, preferably in the vicinity or larger holes to maintain an adequate air flow).

(19) FIG. 5 shows a 3D view of the rear of the hair dryer 10 with the filter mount 30 and filter plate 20 attached. Also shown in more detail is the finger guard 13. The filter mount 30 couples to the rear of the hair dryer via a thread (or any other conventional locking system).

(20) FIG. 6 shows an exploded view of the filter plate 20 and filter mount 30. The filter plate fits into the filter mount 30, guided by lugs 22, 24 being received into corresponding locating holes on the filter plate. These prevent the filter plate rotating within the mount.

(21) No doubt many other effective alternatives will occur to the skilled person. It will be understood that the invention is not limited to the described embodiments and encompasses modifications apparent to those skilled in the art lying within the spirit and scope of the claims appended hereto.