TEXT OF THE DESCRIPTION

Technical field

A hairdryer including:

- a casing,

- a flow duct provided in said casing and having an inlet port and an outlet port,

- a motor unit including an electric motor,

- at least one rotor operable in rotation by means of said electric motor and configured for sucking in an air flow through said inlet port and send it into said flow duct towards said outlet port,

- at least one electrical resistance inserted into said flow duct and configured for heating the air flow taken in by said rotor.

Prior art

Currently known hairdryers are afflicted by a fundamental problem of safety, due to the presence of live parts that are completely exposed to the external environment, and in so far as they are likely to come accidentally into contact with water, thus causing an electric shock that is potentially lethal for the user.

In addition to the well-known accident due to accidental fall of a hairdryer in a bath or a washbasin, there is a further and more dangerous form of accident due to accidental entry of water into the hairdryer when it is not being used. In these circumstances, in the case where the user, unaware of infiltration of water, were to reactivate the motor of the hairdryer, a shortcircuit would be triggered in the resistance that heats the air, in the motor, or worse still in the pushbuttons of the hairdryer, causing a potentially lethal electric shock.

Object of the invention The object of the present invention is to solve the technical problems described previously. In particular, the object of the present invention is to provide a hairdryer that will be intrinsically safe for the user even following upon conditions that might cause an accident of an electrical nature due to accidental contact with water.

Summary of the invention

The object of the present invention is achieved by a hairdryer having all the features listed at the outset of the present description, and moreover characterized in that:

- said at least one electrical resistance is coated with electrically insulating material; and

- said motor unit includes a watertight casing housing said electric motor.

Brief description of the drawings

The invention will now be described with reference to the annexed drawings, which are provided purely by way of non-limiting example and in which:

- Figure 1 is a perspective partial see-through view of a hairdryer according to various preferred embodiments of the invention;

- Figure 2 is a longitudinal cross-sectional view according to the trace II-II of Figure 1;

- Figure 3 is a perspective view of internal components of the hairdryer of Figures 1 and 2;

- Figure 4 is a perspective view of a casing of a motor unit of the hairdryer according to the invention; and

- Figures 5 and 6 are perspective views according to the arrows V and VI of Figure 4, respectively.

Detailed description

The reference number 1 in Figure 1 designates as a whole a hairdryer according to various embodiments of the invention.

The hairdryer 1 includes a casing 2, which develops along a longitudinal axis XI and provided within which is a flow duct 4.

The flow duct 4 is in fluid communication with the external environment by means of an intake port 4IN and a delivery port 40UT. Within the flow duct 4 there are arranged, all coaxial to the axis XI, a rotor 6 and a motor unit 8 including an electric motor M configured for driving the rotor 6 in rotation about the axis XI.

The rotor 6 can be driven in rotation for sucking in an air flow through the port 4IN and sending it through the flow duct 4 towards the port 40UT.

Moreover provided within the flow duct 4 is at least one electrical resistance, which is configured for heating the air flow drawn in by the rotor 6. In the embodiment represented in the figures, the hairdryer 1 includes a first electrical resistance 10 and a second electrical resistance 12, both obtained by means of a nickel-chromium steel wire wound in a cylindrical and/or conical helical path.

Each of the resistances 10, 12 is coated with an electrically insulating material resistant to high temperatures, for example Teflon. The resistances 10, 12 are coated throughout their development.

Each of the resistances 10, 12 is supported radially by means of a plurality of ribs 14 of thermoinsulating material, for example mica. Each of the ribs 14 includes a substantially T-shaped coupling profile T14. With reference to Figure 2, the ribs 14 are fixed to the motor unit 8 by means of the profiles 14T.

The motor unit 8 includes a watertight casing 16, with the electric motor M enclosed within the watertight casing 16 itself. The casing 16 includes a first shell 18 having a substantially hollow ogival shape, a seal 19 (for example, an annular seal of an CD- ring type), and a second shell 20. The seal 19 is set between the shells 19 and 20 to guarantee water tightness at the interface between them. The motor M is fixed by means of screws to the shell 18.

Each of the shells 18, 20 is provided with a plurality of radial eyelets spaced at equal angular spaces apart, which are designated, respectively, by the reference numbers 18A, 20A. These radial eyelets are used for fixing of the ribs 14, and in particular for coupling with the profiles T14, which are configured for engaging in the eyelets 18A, 20A and for being withheld radially by them thanks to the undercut offered by the T-shape.

In particular, the coupling between the shells 18, 20 is obtained axially along the axis XI with interposition of the seal 19 and with the motor M already inside the casing 16, then the shells 18, 20 are fastened together by means of screws S that engage, in corresponding sequences, two axial holes (one smooth and one threaded), one for each of the shells 18, 20.

Preferably, the shell 20 is provided with an array of radial vanes 21, which are configured for co- operating with the rotor 6 for regularizing the air flow within the flow duct 4. Moreover, the radial vanes are configured for acting as cooling fins for dissipating the heat generated by the electric motor M.

The shell 20 is substantially cup-shaped and includes a first radial extension 22 configured for fixing it to the casing 2, and a second radial extension 24 having within it a channel 26 configured for routing one or more electrical wiring systems that carry the supply to the motor M.

The radial extension 24 moreover passes through the casing 2 and is connected thereto through a seal 28, which eliminates the possibility of penetration of water into the interface between the casing 2 and the extension 24. In a position corresponding to the radial extension 24 there is preferably provided a handle (not visible) by means of which the user can grip the hairdryer during use and inside which the electrical wiring coming out of the channel 26 is routed. Once again preferably, on the handle a set of pushbuttons may be provided by co-injection of silicone in order to maintain water tightness.

The shell 20 moreover includes a through hole coaxial to the axis XI, which is traversed by an output shaft 30 of the motor M, fitted on which is the rotor 6. As may be seen in Figures 4 and 6, the shell 20 is closed at the end by a watertight cap 31 that fits on the shaft 30 so as to guarantee water tightness also at the (sliding) interface with the shaft 30. In particular, the cap 31 incorporates a watertight bearing (preferably, a ball bearing) configured for receiving the output shaft 30 and for ensuring water tightness between the latter and the second shell 20.

At the opposite end, the shell 16 also includes a through hole coaxial to the axis XI fitted in which is a plug-like seal 32, which couples in a watertight way with the hole in the casing 16. The plug-like seal 32 includes one or more pairs of through orifices configured for being traversed by the wires that constitute the electrical resistances 10, 12 in such a way that the latter can penetrate within the casing 16 and be incorporated with the wiring that is routed in the channel 26 without jeopardizing water tightness of the casing 16 itself.

In the embodiment illustrated, the resistances 10, 12 are obtained by means of a single wire wound twice, a first time to form the resistance 10 and a second time to form the resistance 12, so that only two portions of wire traverse the seal 32. In other embodiments, the resistances 10, 12 may be provided by means of separate wires - for example, to envisage a differentiated supply thereof in order to vary the heat power, and consequently the temperature of the air - so that there will be two pairs of portions of wire that traverse the seal 32.

It should be noted that, in alternative embodiments, it may be possible to exclude from the coating just the portion of wire that constitutes the electrical resistances intended to penetrate into the casing 16, since this portion of wire would in any case be located in an environment that is in itself watertight .

In the preferred embodiment illustrated herein, moreover set inside the flow duct 4 of the hairdryer is a sleeve 34 having a shape that preferably reproduces, albeit on a smaller scale, the shape of the walls of the casing 2.

The sleeve 34 is located in particular in a position comprised between the electrical resistances 10, 12 and the wall of the casing 2, with respect to which it is supported by means of a plurality of radial ribs 36, preferably obtained in an integral way with the casing 36.

In this way, the flow duct 4 is split (albeit not necessarily throughout the length of the casing 2: this depends upon the axial extension of the sleeve 34 with respect to the casing 2) into a main duct defined substantially inside the sleeve 34, within which find the electrical resistances 10, 12 and at least part of the watertight casing 16 of the motor unit 8 are located, and a secondary flow duct, which has an annular cross section and is set around the sleeve 34, in particular between the latter and the casing 2.

During operation, driving in rotation of the rotor 6 via the electric motor M of the motor unit 8 causes intake of an air flow through the intake port 4IN. This air flow is split into two fractions on account of splitting of the path of the flow duct 4. In particular, a first amount of flow - the larger amount - traverses the main duct and impinges upon the electrical resistances 10, 12, which are supplied electrically, like the motor M, through the bundle of wiring that traverses the channel 26, penetrating into the casing 16, so that the air flow that comes out of the delivery port 40UT will have a higher temperature than the air flow drawn in through the port 4IN.

A second amount of air flow - the smaller amount - passes into the secondary duct, eliminating the moisture that might be present within the casing 2 and cooling the casing 2 as a whole, thus enabling installation of electrical resistances of higher power in the case where the application were so to require. This moreover enables thermal insulation of the area occupied by the resistances through a curtain of cool air generated by the intake within the secondary duct. This solution keeps the whole casing 2 cooled and at the same time improves the air flow, in a way at least roughly resembling the effect exerted by the so-called Vortex winglets typical of a wing profile.

The set of measures of electrical protection adopted on the hairdryer 1, which render the live parts thereof completely insulated from contact with water, prevents any risk of electric shock for the user also in the case of circumstances that might potentially cause an electric shock, such as in the case where the hairdryer were accidentally to fall into water or if water happens to infiltrate into the hairdryer when it is not being used.

In particular, all the electrically supplied parts, namely the motor M and the electrical resistances 10, 12, are in effect electrically insulated from the external environment thanks to:

- coating the surface of the resistances 10, 12 with electrically insulating material; and

- producing the casing 16 of the motor unit 8 as a watertight casing by providing the gaskets 19, 32, 28 and the cap 31.

In this way, in the case where a jet of water were to hit the hairdryer 1, it would at the most manage to impinge on the shell 16 without possibly penetrating therein, and would likewise be able only to impinge on the electrically insulating coating of the resistances 10, 12, without coming into contact with the electrically conductive material. Hypothetically, thanks to these measures, the hairdryer 1 could even function completely immersed in water without suffering any damage and without inflicting any harm on the user.

Of course, in alternative embodiments, it is possible to eliminate the sleeve element 34, thus obtaining a single-walled flow duct. In this way, the entire air flow drawn in by the rotor 6 would come to impinge on the resistances 10, 12, without exerting a cooling action proper on the walls of the casing 2.

Of course, the details of construction and the embodiments may vary widely with respect to what has been described and illustrated herein, without thereby departing from the scope of the present invention, as defined by the annexed claims.