FR3130524A1 - STYLING DEVICE INCLUDING AN IMPROVED BLOWER MODULE WITH CONTRAROTIVE PROPELLERS - Google Patents

Abstract

Hairdressing appliance comprising an improved blower module with counter-rotating propellers.The invention relates to a portable hairdressing appliance (1) comprising an on-board blower module (6) designed to generate a flow of air intended to be projected in the direction of the hair of a user, in which the fan module comprises two axial propellers (8, 9) with blades which are mounted counter-rotating according to coincident axes of rotation, and at least one motor (12, 13) for actuating the propellers in rotation in opposite directions, the propellers each having a blade tip diameter of between 36 mm and 45 mm and a blade height of between 3 mm and 10 mm. 3

Description

STYLING DEVICE INCLUDING AN IMPROVED BLOWER MODULE WITH CONTRAROTIVE PROPELLERS

The present invention relates to the general technical field of hairdressing appliances, for example for domestic use, and more specifically to the field of portable hairdressing appliances designed to blow a flow of air in order to dry and / or facilitate shaping. hair.

The invention relates more specifically to a portable hairdressing device comprising an on-board blower module designed to generate a flow of air intended to be projected by the hairdressing device in the direction of a user's hair.

Hairdressing appliances are known, for example of the hair dryer or hand-held airbrush type, comprising a gripping handle and a blowing head, through which a forced air flow generated by an on-board blower module in the device can be directed at a user's hair.

These known hairdressing devices, if they give overall satisfaction, are nonetheless perfectible. In particular, there is a strong need to obtain hairdressing appliances of ever smaller size, but whose aeraulic performance and in terms of controlling noise pollution are nonetheless optimal. Indeed, reducing the size of hairdressing appliances generally tends to a very significant reduction in their performance.

The objects assigned to the invention therefore aim to provide a response to the above-mentioned needs and problems, and to propose in particular a new portable hairdressing device which has a small footprint while offering excellent performance in terms of aeraulics.

Another object of the invention aims to provide a new portable hairdressing appliance which offers excellent performance both in terms of ventilation and in terms of controlling the noise generated by the appliance in operation.

Another object of the invention aims to provide a new portable hairdressing appliance that is particularly robust and reliable.

Another object of the invention aims to provide a new portable hairdressing appliance of particularly simple construction, and the manufacture of which is relatively easy and with controlled costs.

The objects assigned to the invention are achieved with the aid of a portable hairdressing device comprising an on-board blower module designed to generate a flow of air intended to be projected by said hairdressing device in the direction of the hair of a user, said device being characterized in that said blower module comprises two axial propellers with blades, called upstream propeller and downstream propeller, which are mounted counter-rotating along coincident axes of rotation, and at least one motor for actuating said rotating propellers in opposite directions, said propellers each having a blade tip diameter of between 36 mm and 45 mm and a blade height of between 3 mm and 10 mm.

Other features and advantages of the invention will appear and emerge in more detail on reading the description given below, with reference to the appended drawings, given solely by way of illustrative and non-limiting examples, among which:

illustrates, according to a side view, an embodiment of a hairdressing appliance in accordance with the invention in which the appliance constitutes a “multi-purpose” appliance. To the , the device is illustrated in an operating configuration in “hair dryer” mode;

illustrates the apparatus of the according to a front view;

illustrated, according to a side view in sagittal section II (see ), the apparatus of Figures 1 and 2;

illustrates, according to another front view, the apparatus of FIGS. 1 to 3, illustrated in another operating configuration in “blowing hairbrush” mode;

illustrates, according to a side view in sagittal section II, the hairdressing apparatus of the ;

illustrates schematically, according to a top view in transverse section II-II (see ), part of the apparatus of Figures 1 to 5;

schematically illustrates, in a partial perspective view in sagittal section II, elements of the device of Figures 1 to 5;

schematically illustrates a design detail of the blower module of the apparatus of Figures 1 to 5;

schematically illustrates, in perspective view, the pair of propellers shown in Figures 7 and 8. The distance between the propellers, as shown in , is not respected;

schematically illustrates a downstream face of the upstream propeller shown in Figures 7 to 9, seen in a plane orthogonal to the axis of rotation of the upstream propeller;

schematically illustrates an upstream face of the downstream helix illustrated in FIGS. 7 to 9, seen in a plane orthogonal to the axis of rotation of the downstream helix;

schematically illustrates a detail of a design variant of the blower module of the hairdressing appliance of FIGS. 1 to 5;

schematically illustrates, in perspective view, the pair of propellers of the design variant of the . The distance between the propellers, as shown in , is not respected;

schematically illustrates a detail of another design variant of the blower module of the hairdressing appliance of FIGS. 1 to 5;

schematically illustrates, in perspective view, the pair of propellers of the design variant of the . The distance between the propellers, as shown in , is not respected;

illustrates, in a side view, another embodiment of a hairdressing device according to the invention in which the single-use device constitutes a hair dryer. The protective grille of the air inlet openings has been omitted;

illustrates, in a sagittal cross-sectional view, the apparatus of the ;

schematically illustrates, in a partial perspective view in sagittal section, certain elements of the hairdressing appliance of FIGS. 16 and 17. The upstream propeller has nine blades, while the downstream propeller has eight blades.

The hairdressing device 1 according to the invention is designed to be gripped and manipulated by hand. It is therefore a portable, manual hairdressing appliance 1, preferably intended for use in a domestic setting by a user (woman or man) without any particular professional skills in the field of hairdressing. Preferably, the hairdressing device 1 is designed so that the user uses the hairdressing device 1 on himself, that is to say on his own hair. However, it is perfectly possible for the hairdressing device 1 to be designed for use by the user on the hair of a third person (or other user).

According to a variant, implemented in the embodiment illustrated in particular in Figures 1 to 5, the hairdressing device 1 can constitute a "multi-purpose" device, designed and configured to operate according to at least two different blowing modes. and typically comprising a control mechanism for controlling the passage of the hairdressing appliance 1 from one of the blowing modes to another of the blowing modes. For example, such a “multi-purpose” device could thus be designed and configured to be used alternately by a user according to a “hair dryer” mode (FIGS. 1 to 3) and according to a “blowing hairbrush” mode (FIGS. 4 and 5). According to a variant, implemented in another embodiment illustrated in FIGS. 16 to 18, the hairdressing device 1 can constitute a hair dryer (or hair dryer), which allows a user to dry his (or ) wet or damp hair by blowing in the direction of the hair with a flow of forced, hot or cool air, and to facilitate shaping of the hair. According to another variant, the hairdressing device 1 can constitute a blowing hairbrush, comprising a means of mechanical engagement of the hair, such as bristles, barbs, teeth, etc. The invention is however not limited to these variants and specific embodiments, and it is entirely possible that the hairdressing appliance 1 forms any other portable hairdressing appliance endowed with a function involving the blowing of a flow of air in the direction of a user's hair. For the sake of simplicity, the elements which are identical or similar to the two particular embodiments illustrated in the figures are designated, in the latter, by identical references.

The hairdressing appliance 1 advantageously comprises a handle 2 (or handle) by which the appliance 1 is intended to be held manually in order to be used. The handle 2 thus forms a manual gripping member, intended to be grasped by the user to manipulate the hairdressing appliance 1. Advantageously, the handle 2 is elongated, that is to say that it extends mainly along a single direction in space, corresponding to a direction of longitudinal extension D ₁ -D _1' . In other words, the handle 2 has a slender, slender shape, so that it can be grasped with the whole hand by an adult user. The handle 2 thus extends longitudinally between a first end 2A (or distal end) and a second end 2B (or proximal end) in said mean direction of longitudinal extension D ₁ -D _1' . Preferably, the distance separating the first and second ends 2A, 2B, corresponding to the length of the handle 2, is sufficient to allow all the fingers of one hand of a user to grasp the handle 2. For example, the handle 2 is generally tubular in shape (with, for example, a circular or elliptical middle section, constant or not), and is shaped and dimensioned to ensure a good grip by the user, in particular a "full hand" grip c' is to say by the palm and the fingers of the hand closing around the handle 2.

The hairdressing device 1 advantageously comprises at least one air inlet 3, to draw ambient air from the external environment of the hairdressing device 1, and at least one air blower outlet 4, 23 , which is in aeraulic communication with the air inlet 3 and through which a flow of (forced) air is intended to be blown outwards from the hairdressing device 1 to be projected in the direction of the hair of the 'user. The hairdressing device 1 also advantageously comprises an internal duct placing said (at least one) air inlet 3 in air communication with said (at least one) air blower outlet 4, 23. Advantageously, the device hairdressing machine 1 comprises a blowing head 5, which is provided with said (at least one) air blowing outlet 4, 23, and which is thus designed to blow the air flow out of the hairdressing appliance 1 Advantageously, the blowing head 5 extends the handle 2 from the first end 2A of the latter. Advantageously forming a unitary sub-assembly, the blowing head 5 is preferably integral with the handle 2, that is to say permanently connected to the latter, so that the handle 2 and the blowing head 5 are thus advantageously inseparable by the user. However, it remains conceivable that the blowing head 5 can alternatively be assembled to the handle 2 in a removable, temporary manner, so for example that the blowing head 5 can constitute an interchangeable accessory of the hairdressing device 1, according to the will of the user.

According to a variant, the blowing head 5 can be designed to receive, in a removable manner (for example, by snap-fastening, screwing, press fitting, bayonet locking, etc.), an accessory or end piece (not illustrated), such as by example a nozzle or a diffuser, at the level of the air blower outlet 4, 23 (or one and/or the other of the air blower outlets 4, 23 in the event of a plurality of blower outlets of air), so as to modify the dimensions and/or shape of the useful outlet section of the air flow out of the blower head 5 initially defined by the air blower outlet 4, 23 (and therefore, for example, the speed and / or the size of the air flow blown by the hairdressing device 1). Depending on the configuration of the accessory thus temporarily fixed to the air blowing outlet 4, 23 of the hairdressing appliance 1, and extending the blowing head 5 beyond the air blowing outlet 4, 23 , it is thus possible to achieve a certain number of particular styling effects. According to another variant, the blower head 5 of the hairdressing appliance 1 may, on the contrary, not be designed to receive such accessories or removable tips. The absence of parts that can be detached, disassembled from the blower head 5 by the user facilitates the use of the hairdressing device 1 and prevents the user from misplacing accessories. According to yet another variant, which combines the respective advantages of the two preceding variants, the air blowing outlet 4, 23 of the blowing head 5 of the hairdressing device 1 can advantageously be provided with a means for adjusting the dimensions and/or shape of the useful air passage section at the level of the air blowing outlet 4, 23, such as for example a nozzle, a diffuser or even an adjustable diaphragm, which adjustment means is integral and therefore not separable from the blowing head 5.

The hairdressing appliance 1 in accordance with the invention also comprises a blower module 6 (or “motor-driven ventilation module” or “motor-driven fan unit”) on board, which is designed to generate the flow of air intended to be projected, blown, by the hairdressing device 1 in the direction of the user's hair. Arranged within the hairdressing device 1, the blower module 6 therefore has the function of sucking in ambient air external to the hairdressing device 1, via the air inlet 3 of the hairdressing appliance 1, to generate from this ambient air a flow of forced air intended to be blown out of the hairdressing appliance 1 via the said (at least one) air blowing outlet 4, 23 of the latter.

According to a variant, implemented in the embodiment illustrated in Figures 1 to 5 in particular, the blower module 6 extends the handle 2 from the second end 2B, so that the handle 2 is thus interposed between the module of blower 6 on the one hand and the blowing head 5 on the other hand, between which the handle 2 extends longitudinally. Said blower module 6 can itself be extended by an electrical power cord (shown truncated), provided at its free end with an electrical connection plug. The blower module 6 of the hairdressing device 1 is therefore preferably remote from the blowing head 5 and the handle 2. It is thus possible to size the blower module 6 so as to generate an air flow of one high flow rate, economically, and without impacting the general size of the blower head 5 and the handle 2. In addition, such an arrangement of the blower module 6 advantageously makes it possible to better balance the weight of the hairstyle 1, by a distribution of the masses on either side of the handle 2, which contributes to the comfort of use of the device 1 for the user. Indeed, the masses are thus distributed on either side of his hand, which in particular facilitates his movements when he wishes to carry out hairdressing operations (brushing, etc. ). According to another less advantageous variant (not illustrated), the blower module 6 could be arranged inside the handle 2. In these particular cases, the internal duct, which provides air communication between the air inlet 3 with said (at least one) air blower outlet 4 advantageously comprises an intermediate pipe portion 7 made or arranged inside the handle 2, to put the blower module 6 in air communication with the blower head 5 ( Figures 3 and 5) and thus guide the flow of air generated by the blower module 6 in the direction of the air blowing outlet(s) 4, 23. Advantageously, the internal duct then comprises at least one portion blowing pipe made or arranged inside the blowing head 5, and which is connected on the one hand to said intermediate pipe portion 7 and on the other hand to said air blowing outlet 4, or to the one and/or the other of said air blower outlets 4, 23. According to another variant, implemented in the embodiment illustrated in FIGS. 16 to 18, the blower module 6 can be arranged at the level of , or inside, the blow head 5.

Regardless of the position adopted, the blower module 6 of the hairdressing device 1 according to the invention comprises two axial propellers 8, 9 with blades 10, 11 which are rotatably mounted along axes of rotation A ₁ -A _{1 '} , A ₂ -A _2' combined. In other words, the blower module 6 constitutes an axial (or "propeller") motor-driven fan unit, which is therefore designed to suck in air and propel the flow of air generated from the latter according to a average direction substantially parallel to the axes of rotation A ₁ -A _{1 '} , A ₂ -A _2' of the propellers 8, 9, as illustrated schematically by arrows in the figures. The blower module 6 further comprises at least one motor 12, 13, and preferably two motors 12, 13, typically electric(s), to actuate said propellers 8, 9 in rotation around their axes of rotation A ₁ -A _1' , A ₂ -A _2' respectively. Typically, each of said propellers 8, 9 comprises a hub 14, 15 and a plurality of blades 10, 11 which extend radially from said hub 14, 15. Each of said blades 10, 11 thus extends radially from a root of blade 10A, 11A which forms a blade end at which each blade 10, 11 is secured to the hub 14, 15, up to a blade tip 10B, 11B which respectively forms an opposite free blade end. Furthermore, each of said blades 8, 9 extends axially from a leading edge 10C, 11C to an opposite trailing edge 10D, 11D.

More specifically, the axial propellers 8, 9 with blades 10, 11 of the blower module 6, referred to as the upstream propeller 8 and the downstream propeller 9 (in consideration of the direction of circulation of the air drawn in and the flow of air generated from the latter), are mounted counter-rotating along their respective axes of rotation A ₁ -A _{1 '} , A ₂ -A _2' combined, and said (at least one) motor 12, 13 is designed and configured to actuate said propellers 8, 9 rotating in opposite directions ( ie . in opposite directions of rotation). In what follows, the adjectives "upstream" and "downstream" may be omitted for the sake of brevity when reference is made to the propellers 8, 9 in general, without any direct link with their relative arrangement vis-à-vis the direction air circulation, so that the expression "upstream propeller 8 and downstream propeller 9" can therefore be replaced by the expression "propellers 8, 9". In operation, the upstream propeller 8 therefore draws in ambient air external to the hairdressing appliance 1 via the latter's air inlet 3 to generate an air flow (or "flow of 'primary air') in the direction of the downstream propeller 9, which sucks in said primary air flow to generate the air flow (or "secondary air flow") which will be blown out of the hairdressing appliance 1 via said (at least one) air blowing outlet 4, 23.

In accordance with the invention, the propellers 8, 9 of the blower module 6 each have a diameter Di ₁ , Di ₂ at the end of the blades 10B, 11B which is between 36 mm and 45 mm, and a height h ₁ , h ₂ of blades 10, 11 which is between 3 mm and 10 mm. While the diameter Di ₁ , Di ₂ at the end of blades 10B, 11B corresponds to an external diameter of said propellers 8, 9 in planes orthogonal to the axes of rotation A ₁ -A _1' , A ₂ -A _2' respectively of these latter, said height h ₁ , h ₂ of blades 10, 11 therefore corresponds to the maximum radial distance which separates the root of the blade 10A, 11A from the tip of the blade 10B, 11B of each of said blades 10, 11. Said height h1, h2 of blades 10, 11 therefore corresponds to a difference between a radius at the tip of the blade 10B, 11B and a radius at the root of the blade 10A, 11A of each of the blades 10, 11 (FIGS. 10 and 11).

This particular combination of design characteristics of the blower module 6 advantageously makes it possible to obtain a high-performance blower module 6 with high efficiency, with a bulk which nevertheless remains particularly limited. Indeed, unlike a blower module which would comprise only one and only one axial propeller, such a blower module 6 with counter-rotating axial propellers advantageously has a higher efficiency, the downstream propeller 9 advantageously behaving as an active rectifier making it possible to straighten the air flow (“primary air flow”) generated by the upstream propeller 8, while further increasing the air pressure within the blower module 6. At identical diameter and rotation speed , the implementation of a pair of counter-rotating axial propellers 8, 9 instead of a single and unique axial propeller thus advantageously makes it possible to increase the aeraulic performance by 40% to 50%. The particular dimensional choice described above in terms of diameters Di ₁ , Di ₂ at the end of blades 10B, 11B and heights h ₁ , h ₂ of blades 10, 11 allows the generation of an air flow with a high flow rate for a restricted bulk of the blower module 6. The implementation of such a blower module 6 thus makes it possible, in general, to define a portable hairdressing appliance 1 which has a restricted bulk while offering excellent performance on the aeraulic plan.

It also turns out that, thanks to such a combination of features in the design of the blower module 6, it is possible to obtain, in a particularly advantageous manner, an optimal generated air flow rate that the outlet of air blower 4, 23 of the blower head 5 whether or not equipped with an accessory, nozzle or other means for adjusting the useful section of the air blower outlet 4, 23 of the hairdressing appliance 1 , as previously considered. In the event that, as will be described later in connection with the embodiment illustrated in FIGS. 1 to 5 in particular, the hairdressing device 1 comprises a plurality of air blowing outlets 4, 23 of different configurations, a such a combination of characteristics in terms of the design of the blower module 6 makes it possible to obtain, in a particularly advantageous manner, aeraulic performance, in particular in terms of flow rate, which remains optimal whatever the air blowing outlet 4, 23 selected by the user.

In order to further improve the aeraulic performance and the compactness of the wind tunnel module 6, it is particularly advantageous for the diameter Di ₁ , Di ₂ at the end of the blades 10B, 11B of the propellers 8, 9 to preferably be between 38 mm and 45 mm , and is preferably still equal to 40 mm±0.5 mm, the height h ₁ , h ₂ of the blades 10, 11 being for its part preferably between 4 mm and 8 mm.

Still with a view to further improving the aeraulic performance of the wind tunnel module 6, the blades 10, 11 of the propellers 8, 9 can advantageously be curved, as illustrated in the figures. In this case, the blades 10, 11 of the propellers 8, 9 each preferably have a maximum camber of between 0.1 mm and 0.6 mm, and preferably equal to 0.2 mm±0.05 mm. The maximum camber corresponds to the maximum curvature of the upper surface of the blades 10, 11, that is to say the maximum distance between the chord of the blades 10, 11 (imaginary line joining the leading edge to the trailing edge of the blades) and the surface of the extrados. The length of the cord being advantageously between 10 mm and 22 mm, the maximum camber advantageously corresponds to a relative maximum camber of approximately 2% (that is to say of a value equal to approximately 2% of the length of the the rope). It is moreover also advantageous in terms of aeraulic performance and compactness that the diameter Di ₁ at the tip of the blades 10B of the upstream propeller 8 is preferentially identical to the diameter Di ₂ at the tip of the blades 11B of the downstream propeller 9, as in the embodiments illustrated in the figures.

The maximum thickness of the blades 10, 11 of the propellers 8, 9 can vary along the height h ₁ , h ₂ of the blades 10, 11. Advantageously, the maximum thickness of the blades 10, 11 can be decreasing from the foot of blade 10A, 11A towards the blade tip 10B, 11B of said blades 10, 11 along the height h ₁ , h ₂ of the blades 10, 11. For example, the maximum thickness of the blades 10, 11 can be 2 mm on average along the height h ₁ , h ₂ of the blades 10, 11, varying from 2.1 mm at the blade root 10A, 11A to 1.7 mm at the blade tip 10B, 11B. Such a choice in terms of the thickness of the blades 10, 11 advantageously makes it possible to obtain a good compromise between the weight of the propellers 8, 9 and the mechanical robustness of the blades 10, 11 of the latter. In addition, this advantageously makes it possible to keep a center of the masses closest to the center of the propellers 8, 9 and thus to facilitate the balancing of the latter, in particular in the case where the propellers 8, 9 are made by molding or injection -cast.

Advantageously, as in the embodiment illustrated in FIGS. 1 to 5 in particular, the axes of rotation A ₁ -A _1' , A ₂ -A _2' of the propellers 8, 9 of the blower module 6 are arranged coincident with, or at at least parallel, to the direction of longitudinal extension D ₁ -D _1' of the handle 2. arranged at the level of the second end 2B of the handle 2, or even inside the latter.

Preferably, the propellers 8, 9 are made of rigid plastic material, to reduce the weight and the cost of manufacture. Alternatively, the propellers 8, 9 could be made of metal for example.

Advantageously, the hairdressing device 1 is configured to ensure rotation of each of said propellers 8, 9 at a rotational speed of between 20,000 revolutions per minute (rpm) and 30,000 revolutions per minute, preferably between 25,000 revolutions per minute and 30,000 revolutions per minute, and even more advantageously of the order of 28,000 revolutions per minute. As such, the hairdressing appliance 1 can comprise a control member for controlling the operation of the motor or motors 12, 13 of the blower module 6 rotating according to a rotational speed, constant or not, included in the speed ranges of rotation mentioned above, and this typically by modifying the average electrical supply voltage of the motor or motors 12, 13. It turns out that such a speed of rotation, in combination with the above-mentioned characteristics in terms of diameters Di ₁ , Di ₂ at the end of the blades 10B, 11B and of height h ₁ , h ₂ of the blades 10, 11 of the counter-rotating propellers 8, 9, allows obtaining optimal aeraulic performance, in particular in terms of air flow rate generated by the blower module 6. It is thus advantageously possible to obtain an air flow rate of between 40 m ³ / h and 65 m ³ / h. Such a speed of rotation also makes it possible to obtain a good compromise between the aeraulic performance, the level of noise generated and the service life of the motor or motors 12, 13 of the blower module 6. Preferably, the hairdressing appliance 1 is configured to ensure rotation of said propellers 8, 9 at substantially identical speeds of rotation. For example, an optimum operating point of the motor 12, 13, or of each of the motors 12, 13, of the blower module 6 could be defined by a speed of rotation of approximately 28,000 revolutions per minute, a motor power of 13 W at 28,000 revolutions per minute, under an electric current of 1 A, for an efficiency of 60%. While being included in the ranges of values mentioned above, the speed of rotation of each of the propellers 8, 9 can however possibly vary over time during use of the hairdressing appliance 1. For example, the speed of rotation of each of the propellers 8, 9 can thus optionally fluctuate slightly around a target value of 28,000 revolutions per minute.

In particular for the above-mentioned ranges and values of rotation speed of the propellers 8, 9, it proves advantageous in terms of aeraulic performance that the blades 10, 11 of the propellers 8, 9 are designed and configured so that:
- the blades 10 of the upstream propeller 8 have a pitch angle at the blade root 10A of 45° ± 5°, a pitch angle in the middle of the blade of 41° ± 5° and a pitch angle at the tip of the blade 10B of 37° ± 5°,
- the blades 11 of the downstream propeller 9 having a pitch angle at the blade root 11A of 36° ± 5°, a pitch angle in the middle of the blade of 32° ± 5° and a pitch angle at the tip of the blade 11B by 28° ± 5°.

It therefore follows that the upstream 8 and downstream 9 helices are advantageously twisted. The above pitch angles advantageously refer to the angles formed between a plane orthogonal to the axis of rotation A ₁ -A _1' , A ₂ -A _2' of the helix 8, 9 and a straight line passing through the leading edge and the respective trailing edge of the blades 10, 11 respectively at the root of the blade 10A, 11B, in the middle of the blade and at the tip of the blade 10B, 11B. The pitch angle values may possibly be adapted as a function of the pressure drops generated by elements located upstream and/or downstream of the propellers 8, 9. Thus, in the case where the hairdressing appliance 1 constitutes a brush hairbrush, or at the very least is configured to operate in a "blowing hairbrush" mode, the values indicated above are particularly well suited. In the case where the hairdressing appliance 1 constitutes a hair dryer, or at the very least is configured to operate in a "hair dryer" mode, the induced pressure losses are generally lower, so that the more particular configuration following will be preferred:
- the blades 10 of the upstream propeller 8 have a pitch angle at the blade root 10A of 43° ± 5°, a pitch angle in the middle of the blade of 39° ± 5° and a pitch angle at the tip of the blade 10B of 35° ± 5°,
- the blades 11 of the downstream propeller 9 having a pitch angle at the blade root 11A of 36° ± 5°, a pitch angle in the middle of the blade of 32° ± 5° and a pitch angle at the tip of the blade 11B by 28° ± 5°.

Advantageously, said (at least one) motor 12, 13 of the blower module 6 is a brushed DC electric motor. This type of motor has the advantage of being less expensive and easier to implement than a brushless DC electric motor (or "self-driven synchronous machine with permanent magnets", or " brushless " in English). In addition, this type of motor is particularly well suited for rotating the propellers 8, 9 at a speed of rotation as mentioned above.

Preferably, as in the embodiments illustrated in the figures and as already mentioned above, the blower module 6 of the hairdressing device 1 comprises two motors 12, 13, called upstream motor 12 and downstream motor 13 (in consideration of the direction circulation of the sucked air and of the air flow generated by the blower module 6), to respectively actuate said upstream propeller 8 and said downstream propeller 9 in rotation. In what follows, the adjectives "upstream" and "downstream" may be omitted for the sake of brevity when reference is made to the motors 12, 13 in general, without a direct link with their relative arrangement vis-à-vis the meaning air circulation, so that the expression "upstream motor 12 and downstream motor 13" can therefore be replaced by the expression "motors 12, 13". Advantageously, as illustrated by example in the figures, the upstream 8 and downstream 9 propellers are respectively secured directly to respective motor shafts (or upstream rotor and downstream rotor) of the upstream 12 and downstream 13 motors, the axes of rotation of said motor shafts being coincident with the respective axes of rotation A ₁ -A _{1 '} , A ₂ -A _2' of said propellers 8, 9. Preferably, said motors 12, 13 are of identical designs and dimensions, which makes it possible in particular to simplify the design of the blower module 6 and reduce the cost of manufacture. In particular, the upstream motor 12 and the downstream motor 13 are preferably both brushed direct current electric motors and are advantageously of identical dimensions.

Said motors 12, 13 are preferably arranged axially aligned, that is to say so that the downstream motor 12 is arranged facing the upstream motor 13, the axis of rotation of the motor shaft (or downstream rotor) of the downstream motor 13 being aligned, coincident, with the motor shaft (or upstream rotor) of the upstream motor 12. The upstream motor 12 and the upstream propeller 8 can thus be advantageously arranged aligned axially with the downstream motor 13 and the downstream propeller 9. This makes it possible in particular to improve the compactness of the blower module 6. According to an advantageous variant (not illustrated), said motors 12, 13 can be arranged axially aligned, one with respect to the other, said motors 12, 13 being positioned between said propellers 8, 9, that is to say according to a relative arrangement "in opposition" of the motors 12, 13. According to another advantageous variant, implemented in the embodiments illustrated in the figures, said motors 12, 13 can be arranged aligned axially, one with respect to the other, said propellers 8, 9 being positioned between said motors 12, 13, that is to say according to a relative "head-to-tail" arrangement motors 12, 13. These two arrangement variants prove to be particularly advantageous in the case where, as envisaged above, said motors 12, 13 are brushed DC electric motors. Indeed, motors of this type generally have a preferential direction of rotation. When the motors 12, 13 are chosen with the same preferential direction of rotation, such relative arrangements "in opposition" or "head to tail" allow counter-rotating rotation of the propellers 8, 9, each of the motors 12, 13 rotating according to its preferred direction of rotation. The efficiency of the motors 12, 13 is thus optimized. The so-called "head to tail" variant, in which the motors 12, 13 are arranged axially aligned, the propellers 8, 9 being positioned between the motors 12, 13, is even more advantageous insofar as such an arrangement also allows in particular to easily ensure an optimal relative arrangement of the propellers 8, 9 in terms of distance d , such as the latter will be discussed later. Such an arrangement also allows an arrangement of the air inlet 3 of the hairdressing device 1 at least partly laterally around the upstream motor 12, which makes it possible to improve the compactness of the hairdressing device 1, as well as to improve the cooling of the upstream motor 12, as will also be discussed later.

Alternatively, the wind tunnel module 6 could comprise only a single motor and a bevel gear mechanism, for example, to allow simultaneous and counter-rotating rotation of the propellers 8, 9 using this single motor. Such a design would nevertheless be more complex and more expensive to implement, and furthermore less advantageous in terms of mechanical reliability and acoustically.

Advantageously, at least one of the hubs 14, 15 that each of the propellers 8, 9 respectively comprises is (at least partially) hollow, that is to say hollowed out, and at least one of the motors 12, 13 is at least partially housed within the hollow hub 14, 15 of the corresponding propeller 8, 9. More advantageously still, said propellers 8, 9 each comprise a hub 14, 15 which is hollow, said motors 12, 13 being at least partially housed within said hubs 14, 15. In other words, as illustrated in the figures, a at least part of the upstream motor 12 is housed within a recess of the hollow hub 14 of the upstream propeller 8, while at least part of the downstream motor 13 is respectively housed within a recess of the hollow hub 15 of the downstream propeller 9. The size of the blower module 6 along the axes of rotation A ₁ -A _1' , A ₂ -A _2' of the propellers 8, 9 is thus advantageously reduced. As such, one and/or the other (and therefore preferably both) of the propellers 8, 9, typically have a diameter at the root of the blade 10A, 11A which is (slightly) greater a respective outer diameter of the motor 12, 13 corresponding. For example, depending on the external diameter of the motor 12, 13 concerned, the corresponding propeller 8, 9 may have a diameter at the root of the blade 10A, 11A advantageously between 25 mm and 32 mm.

The number of blades 10, 11 that each of the propellers 8, 9 respectively comprise has an impact on the performance of the wind tunnel module 6. Indeed, the greater the number of blades 10, 11, the greater the quantity of mechanical energy of the engine 12, 13 transmitted to the air is important. Nevertheless, too many blades 10, 11 leads, by construction, to the implementation of blades 10, 11 of too small dimensions, which tends to degrade the efficiency of the propellers 8, 9. Conversely, too many low blades 10, 11 would limit the performance of the propeller 8, 9 and would require a propeller 8, 9 of large dimensions. At the same time, it also proves interesting, in terms of acoustic performance, that the propellers 8, 9 advantageously comprise a different number of blades 10, 11, and even more advantageous than the numbers of blades 10, 11 of the propellers 8, 9 are chosen to be prime among themselves (that is to say that the number of blades 10, 11 are different, and that they do not admit any common divisor, if not unity). This prevents the blades 11 of the downstream propeller 9 from crossing the blades 10 of the upstream propeller 8 at the same time. The number of blades 10 of the upstream propeller 8 is moreover preferably greater than the number of blades 11 of the downstream propeller 9. The mean pitch angle of the upstream propeller 8 being advantageously greater than that of the downstream propeller 9, it is thus possible to design the propellers 8, 9 with similar axial dimensions and therefore to have a relatively symmetrical construction.

Given the foregoing, the upstream propeller 8 thus advantageously has a number of blades 10 comprised between 5 and 11, and preferably equal to 9, while the downstream propeller 9 advantageously exhibits a number of blades 11 comprised between 3 and 10, and preferably equal to 8, said numbers of blades 10, 11 being preferably chosen to be relatively prime. By way of examples, FIGS. 6 to 11 schematically illustrate a particularly advantageous variant in which the upstream propeller 8 comprises nine blades 10 and the downstream propeller 9 comprises eight blades 11. This variant is also implemented in the mode of embodiment of the device 1 illustrated in Figures 16 to 18. Figures 12 and 13 schematically illustrate a variant in which the upstream propeller 8 comprises seven blades 10 and the downstream propeller 9 comprises six blades 11. Figures 14 and 15 illustrate schematically yet another variant, in which the upstream propeller 8 comprises five blades 10 and the downstream propeller 9 comprises four blades 11. Yet another variant (not shown) in which the upstream propeller 8 would comprise five blades 10 and the downstream propeller 9 would comprise three blades 11 could be envisaged, although less preferential than the variants above.

Preferably, the propellers 8, 9 of the blower module 6 have respective strengths of less than 1, while being preferentially greater than 0.9, and more preferentially still equal to 0.95±0.01. Solidity (or "solidity coefficient") compares the area of a propeller disc which is occupied by solid components (i.e. by the blades) and with the remaining area of the disc which is open to air circulation (i.e. not occupied by the blades). Increasing the strength of a propeller results in a better transfer of mechanical energy from the engine to the air sucked in by the propeller. In addition, a strength of less than 1 advantageously allows axial demolding of the helices when the latter are manufactured by molding or by plastic injection (or injection moulding), which simplifies the manufacture of the helices 8, 9 and reduces the costs thereof. Conversely, a solidity greater than 1 would require the use of molds with drawer(s), which are more complex and expensive to implement, to manufacture said propellers 8, 9 by molding or by plastic injection. The preferential choice of a strength of the propellers 8, 9 which is equal to 0.95 ± 0.01 advantageously makes it possible to ensure sufficient transfer of the mechanical energy from the motor or motors 12, 13 to the air sucked in by the propellers 8, 9, while remaining within the limits of the torque deliverable by the motor(s) 12, 13.

Advantageously, said at least one motor 12, 13 and the propellers 8, 9 of the blower module 6 are arranged within the internal duct which ensures, as mentioned previously, the aeraulic communication of the air inlet 3 of the hairdressing device 1 with said (at least one) air blowing outlet 4 of the latter. When the blower module 6 advantageously comprises two motors 12, 13, as in the embodiments illustrated in the figures, said motors 12, 13 and propellers 8, 9 are advantageously arranged within said internal duct. Alternatively, but less advantageously in terms of size and simplicity of design, the propellers 8, 9 could be arranged in the internal duct, the motor or motors 12, 13 being arranged outside the latter.

The blower module 6 thus preferably comprises at least one motor support for holding said (at least one) motor and said propellers 8, 9 in position inside said internal duct. In the preferential case where, as in the embodiments illustrated in the figures, the blower module 6 comprises two motors 12, 13, namely said upstream motor 12 and said downstream motor 13, the blower module 6 advantageously comprises a motor support upstream 16 and a downstream motor support 17, respectively designed and configured to ensure the maintenance in position of the upstream motor 12 and the upstream propeller 8, and of the downstream motor 13 and the downstream propeller 9, inside the duct internal of the hairdressing device 1. The upstream motor support 16 and the downstream motor support 17 can then form one and the same part, monolithic, or form separate parts, as in the embodiments illustrated in the figures. In what follows, the adjectives "upstream" and "downstream" may be omitted for the sake of brevity when reference is made to the engine mounts 16, 17 in general, with no direct link to their relative arrangement vis-à-vis the direction of air circulation, so that the expression “upstream motor support 16 and downstream motor support 17” could therefore be replaced by the expression “motor supports 16, 17”. Advantageously, as illustrated by example in FIGS. 3, 5 to 7, 17 and 18 in particular, the motor support(s) 16, 17 comprise a peripheral tubular wall 16A, 17A of circular section which defines a portion air duct, and one or more support arms 16B, 17B which extend inwardly of said air duct portion, between a first end from which the support arm(s) 16B, 17B are connected to the peripheral tubular wall 16A, 17A and a second opposite end connected to the motor(s) 12, 13 arranged inside said air duct portion. As such, the peripheral tubular wall 16A, 17A of the motor support(s) 16, 17 can advantageously contribute to forming the internal duct of the hairdressing appliance 1, so that the duct portion of air defined by the peripheral tubular wall 16A, 17A advantageously forms a portion of said internal duct. Advantageously, the engine support(s) 16, 17 may comprise a nacelle 16C, 17C, secured to the second end of the support arm(s) 16B, 17B and designed and configured to receive and hold within it the single motor or one of said upstream 12 and downstream 13 motors. and downstream 9, advantageously respectively mounted on the motor shafts of the upstream 12 and downstream 13 motors, can thus advantageously be shrouded radially respectively by an internal face of the peripheral tubular walls 16A, 17A of the upstream motor support 16 and of the downstream motor support 17.

Alternatively, according to a variant not shown, the motor support(s) 16, 17 could not include peripheral tubular wall(s) 16A, 17A of circular section as envisaged above. above, and the blower module 6 could advantageously comprise in this case a tubular nozzle of circular section, inside which the motor(s) 12, 13 and the propellers 8, 9 would be held arranged in position by one or engine support(s) comprising support arms fixed to an internal face of the tubular nozzle. The tubular nozzle would then advantageously form in this case a radial fairing for each of said upstream 8 and downstream 9 propellers.

In any case, it proves to be advantageous in terms of aeraulic performance that the upstream 8 and downstream 9 propellers of the blower module 6 are preferentially streamlined, that is to say that the blower module 6 comprises a radial fairing (or upstream fairing and downstream fairing) to radially fair the upstream 8 and downstream 9 propellers. 10, 11 of the propellers 8, 9. More specifically, it is preferable, as in the embodiments illustrated in the figures where the blower module 6 therefore comprises upstream and downstream fairings respectively formed by the peripheral tubular walls 16A, 17A of the supports upstream 16 and downstream 17 motors, that the blower module 6 has a radial clearance of between 0.2 mm and 0.8 mm between the tip of the blade 10B, 11B of the blades 10, 11 of the propellers 8, 9 and the internal faces respective said upstream and downstream fairings. For example, a good compromise between the control of the risk of formation of vortices at the tip of the blade 10B, 11B and the ease of design and manufacture of the wind tunnel module 6 can be obtained when said radial clearance is approximately 0.5 mm.

In the case (not shown) where the blower module 6 comprises a single and unique motor to drive the propellers 8, 9 in counter-rotating rotation, it is advantageous to provide that said single motor is then arranged in the internal duct of the device hairdresser 1 upstream of said propellers 8, 9 (in consideration of the direction of air circulation inside the hairdresser 1), and that the air inlet 3 of the hairdresser 1 is arranged at least partly laterally around said single motor. In the more preferred case, illustrated in the figures, where the blower module 6 comprises two motors 12, 13, namely said upstream motor 12 and said downstream motor 13, which are arranged axially aligned (that is to say arranged according to an axial alignment), the propellers 8, 9 being positioned between the motors 12, 13 (“head-to-tail” arrangement), said motors 12, 13 and said propellers 8, 9 being arranged within said internal duct, it is mutually advantageous to provide that the air inlet 3 of the hairdressing appliance 1 is arranged at least partly laterally around said upstream motor 12 (FIGS. 3, 5 and 17). Here, the term "at least partly laterally around said engine" and "at least partly laterally around said upstream engine 12" advantageously means the fact that the air inlet 3 is arranged at least partly facing the engine single motor or of the upstream motor 12 and in line with the axis of rotation of the motor shaft (or rotor) of the latter, and this following at least part of the axial periphery of said single motor or of said upstream motor 12. The air exterior can thus be sucked into the hairdressing appliance 1 via said air inlet 3 along an average suction direction which is substantially orthogonal to the axis of rotation of the motor shaft (or rotor) of said single motor or of said upstream motor 12. Such an arrangement of the air inlet 3 of the hairdressing device 1 makes it possible to further reduce the overall size of the latter, and also makes it possible to cool said motor. Preferably again, said air inlet 3 is arranged laterally along substantially the entire axial periphery of said single motor or of said upstream motor 12, so as in particular to ensure optimum suction of the external air inside the hairstyle 1 and optimal operation of the blower module 6.

As such, as illustrated by example in Figures 3, 5, 7, 17 and 18, the peripheral tubular wall 16A of the upstream motor support 16 can advantageously be pierced with at least one air intake vent 16D which is arranged at least partly laterally around the upstream motor 12, the air inlet 3 of the hairdressing appliance 1 being positioned opposite said air intake vent 16D. Even more advantageously, the peripheral tubular wall 16A of the upstream motor support 16 can advantageously be pierced with a plurality of air intake vents 16D, which are arranged in an evenly distributed manner along the perimeter of the peripheral tubular wall 16 , said air inlet 3 is arranged opposite said air intake vents 16D. Advantageously, as in the embodiment illustrated in FIGS. 1 to 5 in particular, the blower module 6 can comprise a casing 18, inside which are arranged the motor or motors 12, 13 and the propellers 8, 9, as well as if necessary, the said motor support(s) 16, 17, and which is secured to the second end 2B of the handle 2. Advantageously, an external face of the casing 18 of the blower module 6 thus defines a portion of the external envelope of the device hairdresser 1, which extends another outer casing portion of the hairdressing device 1 respectively defined by an outer face of the handle 2. Alternatively, as in the embodiment illustrated in Figures 16 and 17 in particular, said housing 18 can define a rear portion of the blower head 5, opposite a front portion of the blower head 5 which carries the air blower outlet 4 (FIGS. 16 and 17). The air inlet 3 of the hairdressing appliance 1 can then comprise at least one, and preferably several, opening(s) 19 made through the casing 18 of the blower module 6 and connected if necessary in aeraulic communication with the air intake vent(s) 16D of the upstream motor support 16. A protective grille 20 (omitted in FIGS. user safety. In the event that the blower module 6 would be arranged inside the handle 2 or inside the blowing head 5, and not at the level of the second end 2B of the handle 2, the input of air 3 of the hairdressing device 1 could alternatively comprise one or more openings made through an outer face of the handle 2, or respectively through an outer face of the blower head 5.

Advantageously, the blower module 6 of the hairdressing appliance 1 can comprise a downstream static rectifier to further straighten the air flow downstream of the downstream propeller 9 and thus improve the performance of the blower module 6. For example, as in the embodiments illustrated in the figures and in particular in the , such a downstream static rectifier can be carried by the downstream motor support 17, and be advantageously formed, at least in part, by support arms 17B of the downstream motor 13, the latter advantageously having a concave face portion oriented opposite the direction of rotation of the downstream propeller 9. Alternatively, the downstream static rectifier could be independent, separate, from the motor support(s) 16, 17 and include, for example, fins arranged immobile within the internal duct of aeraulic communication between the air inlet 3 and the air blower outlet(s) 4, 23 of the hairdressing device 1.

If it has, as explained above, advantages in terms of aeraulic performance, the implementation of a pair of 8, 9 axial propellers mounted counter-rotating may however prove to generate a higher noise level than the implementation of a single axial propeller. Indeed, in the case of counter-rotating propellers 8, 9, turbulence generated by the upstream propeller 8 can come into contact with the downstream propeller 9, which can be a source of amplification of the noise emitted. In addition, the use of two motors 12, 13 to each actuate one of the propellers 8, 9 in rotation, as envisaged above, also tends to increase the noise generated during the operation of the blower module 6. To improve the performance of the blower module 6 in terms of sound emissions, while nevertheless maintaining a completely satisfactory air flow rate generated by the blower module 6, certain additional technical measures, which will be detailed below , can be advantageously implemented, each taken independently or preferably in combination. These technical measures prove particularly advantageous in the preferred ranges of rotational speed of the upstream 8 and downstream 9 propellers mentioned above.

Preferably, the blades 10, 11 of at least one of the propellers 8, 9 of the wind tunnel module 6 are distributed in a non-equidistant manner radially, that is to say in a non-equidistant manner around the axis rotation A ₁ -A _{1 '} , A ₂ -A _2' of said propeller 8, 9, so that the radial spacing of the blades 10, 11 of said propeller 8, 9 is therefore not constant. Even more preferably, the blades 10, 11 of each of the propellers 8, 9 are distributed in a non-equidistant manner radially, that is to say in a non-equidistant manner around the axes of rotation A ₁ -A _1′ , A ₂ -A _{2 '} respective of said propellers 8, 9. The use of non-equidistant blades on the circumference of the hub 14, 15 of at least one of the propellers 8, 9, and preferably of each of the propellers 8, 9 , advantageously makes it possible to reduce the amplitude of the lines at the frequency of passage of the blades (FPP) and its harmonics. The acoustic disturbance can thus be advantageously reduced insofar as the line of high amplitude at the frequency of passage of the blades is thus replaced by several lines of lesser amplitude. Furthermore, in the case where the blower module 6 comprises support arms 17B for the downstream motor 13 and/or a downstream static rectifier, arranged downstream of the downstream propeller 9, the implementation of blades 11 not equidistant radially for the downstream propeller 9 advantageously makes it possible to reduce the acoustic disturbance caused by any whistling linked to the frequency of passage of the blades 11 of the downstream propeller 9 opposite the support arms 17B of the downstream motor 13 and/or of the downstream static rectifier. It is nevertheless desirable to maintain a positioning of the center of gravity of the propeller 8, 9 concerned, or of each of the propellers 8, 9 if necessary, on the axis of rotation A ₁ -A _{1 '} , A ₂ -A _2' of the propeller 8, 9, in order to guarantee good balancing of the propeller 8, 9 in rotation, which is favorable in terms of mechanical reliability and control of the vibrations and noise generated by the blower module 6 This is why, in the preferred variant described above where the upstream propeller 8 and the downstream propeller 9 respectively comprise nine and eight blades 10, 11 (FIGS. 7 to 11, 17 and 18 in particular), the upstream propeller 9 has three equal angular sectors each comprising three blades 10 of different profile chord lengths (or widths) (namely advantageously a blade 10 of a reference chord length, a blade 10 of an equal chord length to said reference chord length increased by 10%, and a blade 10 with a chord length equal to said reference chord length decreased by 10%). The downstream propeller 9 has for its part four equal angular sectors each comprising two blades 11 of different chord length (namely advantageously a blade 11 of a chord length equal to a reference chord length increased by 10%, and a blade 11 with a chord length equal to said reference chord length reduced by 10%). The profile chord of a blade is an imaginary straight line that connects the leading edge to the trailing edge of a blade. Such a design can also apply mutadis mutandis in particular to propellers comprising four or six blades 10, 11.

In order to prevent turbulence generated at the trailing edge 10D of the blades 10 of the upstream propeller 8 attacking the downstream propeller 9 at the same time at the foot of the blades 11A and at the tips of the blades 11B, each of the blades 10 of the upstream propeller 8 preferably has a generatrix curvature which is in the opposite direction to a respective generatrix curvature of each of the blades 11 of the downstream propeller 9 (as visible in example in FIGS. 8 and 9). This advantageously makes it possible to reduce the frequency peak linked to an interaction between turbulence created at the trailing edges 10D of the blades 10 of the upstream propeller 8 and the leading edges 11A of the blades 11 of the downstream propeller 9. The noise generated is thus reduced.

It has been observed that the axial distance between the two propellers 8, 9 can have an impact on the airflow noise generated, but also on the airflow performance. As such, and to obtain a good compromise between noise reduction and obtaining good aeraulic performance, the propellers 8, 9 of the wind tunnel module 6 are preferably arranged so that a mean leakage plane P _mf of the upstream propeller 8, in which are inscribed the trailing edges 10D of the blades 10 of the upstream propeller 8, is arranged at a distance d of between 5 mm and 10 mm, preferably between 6 mm and 10 mm, and more preferably still equal to 8 mm, from an average plane of attack P _ma of the downstream propeller 9, in which are respectively inscribed the leading edges 11C of the blades 11 of the upstream propeller 9 (FIGS. 8, 12 and 14 ). Beyond these ranges of values, the acoustic impact is certainly reduced, but the aeraulic performances are likely to be degraded.

In order to homogenize the air flow (or "primary air flow") generated by the upstream propeller 8 and to reduce the impact of the turbulence generated by said upstream propeller 8, the blower module 6 can advantageously comprise a porous media 27, which is arranged between the propellers 8, 9, so that said porous media 27 is thus interposed axially in the air flow generated by the upstream propeller 8, upstream of the downstream propeller 9. Due to of its porosity, said porous medium 27 is therefore permeable to air so that the air flow generated by the upstream propeller 8, and preferably all of said air flow, encounters and passes through the porous medium 27 to reach the downstream helix 9. Advantageously, as illustrated in the figures, the porous media 27 occupies the entire useful section of the internal duct of the hairdressing appliance 1 between said helices 8, 9. Advantageously, the porous media 27 is positioned at equal axial distance from the upstream 8 and downstream 9 propellers. The porous medium 27 is thus advantageously positioned interposed in the flow of air circulating from the upstream propeller 8 to the downstream propeller 9, as far as possible on the one hand from the edges leakage 10D of the blades 10 of the upstream propeller 8, and on the other hand of the leading edges 11C of the blades 11 of the downstream propeller 9. This contributes to improving the performance of the device 1 in terms of sound. Advantageously, the porous medium 27 thus typically being along a mean extension plane which is oriented perpendicular to the axes of rotation A ₁ -A _1' , A ₂ -A _2' of the helices 8, 9, and which is positioned at axial equidistance of the mean plane of flight P _mf of the upstream propeller 8, and of the mean plane of attack P _ma of the downstream propeller 9 (FIGS. 8, 14 and 18).

Advantageously in terms in particular of simplicity and low cost of design, the porous medium 27 forms (or at the very least comprises) a grid, as in the embodiments illustrated in the figures. The porous medium 27 therefore advantageously forms a generally two-dimensional element having two opposite faces, each oriented respectively opposite one of the helices 8, 9, and provided with a plurality of through holes constituting meshes distributed in a homogeneous manner and whose openings are of identical shapes and dimensions. For example, as in the embodiments illustrated in the figures, said grid can be formed from an assembly of intersecting wires or bars. In this case, the grid can therefore optionally be a piece of canvas or fabric, that is to say in general any woven element having an alternation of threads, bars, bars, etc. and empty spaces that allow the flow of air to pass.

Alternatively, the porous medium 27 can also be formed by, or comprise, a non-woven porous element, but always having an alternation of material and empty spaces, such as for example a foam. The porous media 27 can then have cells or pores which allow the flow of air to pass.

As mentioned previously, the porous medium 27 advantageously forms a generally two-dimensional element. Thus, the porous media 27 can take the form of a square, a rectangle, a disc, or any other geometric shape corresponding substantially to the internal section of the internal conduit in which it is arranged. In other words, the thickness of the porous medium 27 is negligible compared to its two other dimensions: length or width, or even compared to its diameter in the case where, as illustrated in the figures, the porous medium 27 forms a disc . It is important to select a porous medium 27 with a minimum thickness, in order to be able to bring the upstream 8 and downstream 9 propellers as close as possible, in order to optimize their aeraulic performance but also to improve the compactness of the hairstyle 1.

It has been observed that, the lower the porous media 27 has (or void ratio), the greater the reduction in acoustic power, but the more the aeraulic performance of the wind tunnel module 6 is degraded. In order to obtain a good compromise between the increase in the pressure drops induced by the porous media 27, implying a drop in performance, and the limitation of airflow noise, said porous media 27 preferably has a porosity of between 30% and 90 %, more preferably between 50% and 85%, and more preferably equal to 66%. Such a preferential value advantageously makes it possible to reduce the noise by more than 2 dB(A). Alternatively, the blower module 6 could comprise, instead of the porous medium 27, a static straightener (such as for example fixed fins) to straighten the air flow generated by the upstream propeller 8 in order to limit the turbulence at the inlet of the downstream propeller 9. This variant nevertheless proves to be less advantageous in terms of acoustic/aeraulic performance compromise than the use of a porous medium 27 as envisaged above.

Advantageously, the blower module 6 can comprise means for damping the vibrations of the motor or motors 12, 13, such as in particular means for absorbing the vibrations. For example, as in the embodiments illustrated in the figures, the upstream engine support 16 and the downstream engine support 17 can be, one and/or the other provided with one or more shims 16E, 17E in an elastically deformable material (for example in elastomer, also called " silent block ") arranged between the motor 12, 13 and the corresponding motor support 16, 17, for example within the respective nacelles 16C, 17C of the motor supports 16, 17 ( figures 7 and 18 in particular).

Preferably, the hairdressing appliance 1 further comprises an electric heating element 21 to heat the flow of air generated by the blower module 6 and blown outwards by said (at least one) air blowing outlet 4. The electrical heating element 21 can be formed by any suitable electrical heating means, based on any technology making it possible to transform electrical energy into thermal energy. Preferably, the electric heating element 21 uses Joule effect heating, it being understood that the invention is not limited to a particular heating technology, provided that the electric heating element 21 is integrated into the hairdressing device 1 and powered electrically. For example, the electrical heating element 21 comprises at least one electric heating resistor formed by a winding of metallic conductor wires (not shown in the figures, for example in nichrome) around a core insulating (eg mica), which has for example a cruciform section. As illustrated in FIGS. 3 and 5, the electrical heating element 21 can be embedded permanently inside the handle 2 of the hairdressing appliance 1, advantageously inside the intermediate pipe portion 7 of the internal pipe of the hairdressing appliance 1, so as to be thus interposed in the air flow, downstream of the blower module 6 with respect to the direction of air circulation (FIGS. 3 and 5). Alternatively, the electric heating element 21 could be arranged inside the blower head 5, as illustrated in the example at .

As mentioned above, and as in the embodiment illustrated in Figures 1 to 5 in particular, the hairdressing device 1 can advantageously constitute a "multi-purpose" device, designed and configured to operate according to at least two different blowing modes and typically comprising a control mechanism 22 for controlling the passage of the hairdressing appliance 1 from one of said blowing modes to another of said blowing modes.

The hairdressing appliance 1 can then comprise a plurality of air blowing outlets 4, 23, namely at least a first air blowing outlet 4 and a second air blowing outlet 23 which are distinct one from the other, and an air direction member 24 which is movably mounted at least between:
- a first air direction configuration in which the air direction member 24 directs the air flow generated by the blower module 6 towards the first air blowing outlet 4 according to a first of said blowing modes (Figures 1 to 3), and
- a second air direction configuration in which the air direction member 24 directs the air flow generated by the blower module 6 towards the second air blowing outlet 23 according to a second of said blowing modes (figures 4 to 5),
the control mechanism 22 being connected to the air directing member 24 to control each passage of the air directing member 24 from one to the other of said first and second air directing configurations.

For example, as in the embodiment illustrated in the figures, said control mechanism 22 may be a push-push button mechanism 22A, the button 22A of the control mechanism 22 then being preferably mechanically connected to the steering member of the air 24 to mechanically transform each movement of the button 22A under the effect of a push exerted on the button 22A, typically by a finger of the user, into a movement of the air direction member 24 of one to the other of said first and second air direction patterns.

Still as in the embodiment illustrated in particular in FIGS. 1 to 5, such a “multi-purpose” device can be more specifically designed and configured to be able to be used alternately by a user according to a “hair dryer” mode (first mode blowing / first air blowing outlet 4, Figures 1 to 3) and in a "blowing hairbrush" mode (second blowing mode / second air blowing outlet 23, Figures 4 and 5).

As such, as illustrated in Figures 1 to 5, the blower head 5 of the hairdressing device 1 can advantageously comprise a housing 25 which carries the first air blower outlet 4. As illustrated in in particular, the first air blowing outlet 4 may have an opening of generally oblong, elongated shape, to blow the flow of air out of the hairdressing device 1 in the form of an air knife. Alternatively, the first air blow outlet 4 could have, for example, an opening of generally circular shape to blow the air flow in a substantially cylindrical or frustoconical shape. The blower head 5 of the hairdressing appliance 1 can also advantageously comprise a working element 26 (or “plateau” or even working “pad”) which carries the second air blowing outlet 23 and which comprises a mechanical engagement element 26A of the hair, able to interact mechanically with the user's hair in such a way as to brush it, to style it and/or even to comb it. Typically, the mechanical hair engagement member 26A may comprise a plurality of bristle rows or strips and/or brush bristles (FIGS. 1 and 3-5).

Advantageously, the second air blower outlet 23 may comprise a first air blower outlet portion 23A and a second air blower outlet portion 23B, distinct from each other and positioned on either side. other side of the hair mechanical engagement member 26A ( ), the first and second air blowing outlet portions 23A, 23B being preferably shaped and configured to blow the flow of air in the direction of the mechanical engagement element 26A of the hair. Advantageously, the working element 26 can be mounted for rotation relative to the handle 2, while the housing 25 of the blowing head 5 which is mounted fixed, immobile, relative to the handle 2. More precisely, as in the mode embodiment illustrated in the figures, the working element 26 can be mounted for rotation, pivoting, relative to the handle 2 in a predetermined angular range along an axis of rotation (not shown) between at least a first angular position in which the flow of air is intended to be blown out of the hairdressing device 1 via the first air blowing outlet portion 23A, and at least one second angular position, distinct from the first angular position, in which the air flow is intended to be blown out of the hairdressing appliance 1 via the second air blowing outlet portion 23B. Preferably, the axis of rotation of the working element 26 with respect to the handle 2 is parallel to, or coincides with, the direction of longitudinal extension D ₁ -D _{1 '} of the handle 2, as in the embodiment illustrated in the figures (FIGS. 1 to 5 in particular). The working element 26 is therefore capable of occupying a plurality of different angular orientations (or positions) relative to the handle 2, by pivoting around the axis of rotation of the working element 26, in a predetermined angular range. and advantageously bounded. The working element 26 has a certain latitude of rotation around its axis of rotation, and is therefore capable of being able to pivot, oscillate, relative to the handle 2 in said predetermined angular range, while blowing the flow of air out of the hairdressing appliance 1 by one and/or the other of the first and second air blowing outlet portions 23A, 23B carried by the working element 26. Thus, the interaction between the hair of the user and the mechanical engagement element 26A of the hair of the working element 26 may cause the working element 26 to pivot relative to the handle 2 under the effect of a tensile force exerted by the hair of the user on the mechanical engagement element 26A of the hair. When the second blowing mode of the hairdressing appliance 1 is selected, this then has the effect of blowing the air flow selectively through one and/or the other of said air blowing outlet portions 23A, 23B according to the direction of brushing or styling the hair, and therefore according to the direction of pivoting of the working element 26 in the direction of one or the other of the first and second angular positions. In this way, the flow of air is advantageously always blown as close as possible to the hair of the user, from the root to the tip of the hair, without requiring any particular action or reflection on the part of the latter other than that to brush his hair using the hairdressing device 1. The hairdressing device 1 thus makes it possible to easily obtain particularly satisfactory hair styling and shaping effects. Moreover, given the fact that only the working element 26 is mounted for rotation with respect to the handle 2 in this case, and not the whole of the blowing head 5, the hairdressing appliance 1 is particularly ergonomic. and easy to use, even by a user without special professional skills in hairdressing.

Preferably again, the hairdressing device 1 can be designed and configured in such a way that the working element 26 is capable of occupying a third angular position (FIGS. 4 and 5), which is angularly intermediate to the first and second angular positions, and in which the flow of air is intended to be blown out of the hairdressing device 1 simultaneously via the first and second air blowing outlet portions 23A, 23B carried by the working element 26. Advantageously, the third angular position is a position angularly median to the first and second angular positions within the predetermined angular range. More advantageously still, the third angular position is a rest position, the working element 26 comprising a return member, preferably elastic, provided to automatically return the working element 26 to the third angular position when the work 26 occupies one or the other of the first and second angular positions. Thus, in the absence of force exerted on the working element 26 by interaction between the hair of the user and the mechanical engagement element 26A of the hair, the working element 26 advantageously returns by itself automatically in the third intermediate angular position. The force and amount of rotation of the working element 26 by interaction between the user's hair and the mechanical engagement element 26A of the hair of the working element 26 which will subsequently be necessary to reach one or the other of the first and second angular positions are thus advantageously reduced, which further improves the ease and comfort of use of the hairdressing appliance 1. For example, the return member may comprise a leaf spring (or leaf-spring) working in bending or a rod-spring working in bending.

As mentioned above, the design of the blower module 6 in accordance with the invention proves to be particularly advantageous in the case where the hairdressing appliance 1 constitutes a "multi-purpose" appliance and in particular a hairdressing appliance 1 designed and configured to be able to be used alternately in a “hair dryer” mode and in a “blower brush” mode. Indeed, such a design makes it possible to obtain aeraulic performances, in particular in terms of flow, which remain optimal whatever the air blowing outlet 4, 23 used according to the blowing / operating mode selected by the user, while maintaining a particularly limited size of the blower module 6, and therefore of the hairdressing appliance 1.

Claims (17)

Portable hairdressing device (1) comprising an on-board blower module (6) designed to generate a flow of air intended to be projected by said hairdressing device (1) in the direction of a user's hair, said hairdressing device ( 1) being characterized in that said blower module (6) comprises two axial propellers (8, 9) with blades (10, 11), called upstream propeller (8) and downstream propeller (9), which are mounted counter-rotating according to axes of rotation (A ₁ -A _1' , A ₂ -A _2' ) coincident, and at least one motor (12, 13) for actuating said propellers (8, 9) in rotation in opposite directions, said propellers (8, 9) each having a diameter (Di ₁ , Di ₂ ) at the end of the blades (10B, 11B) of between 36 mm and 45 mm and a height (h ₁ , h ₂ ) of the blades (10, 11) of between 3 mm and 10mm. Hairdressing device (1) according to the preceding claim, characterized in that the said diameter (Di ₁ , Di ₂ ) at the end of the blades (10B, 11B) of the propellers (8, 9) is between 38 mm and 45 mm, and is preferably equal to 40 mm ± 0.5 mm, said height (h ₁ , h ₂ ) of blades (10, 11) preferably being between 4 mm and 8 mm. Hairdressing appliance (1) according to any one of the preceding claims, characterized in that it is configured to ensure rotation of each of the said propellers (8, 9) at a speed of between 20,000 revolutions per minute and 30 000 revolutions per minute, and preferably between 25,000 revolutions per minute and 30,000 revolutions per minute. Hairdressing appliance (1) according to any one of the preceding claims, characterized in that

• the blades (10) of the upstream propeller (8) have a pitch angle at the root of the blade (10A) of 45° ± 5°, a pitch angle in the middle of the blade of 41° ± 5° and an angle of blade tip pitch (10B) of 37° ± 5°,
• the blades (11) of the downstream propeller (9) having a pitch angle at the root of the blade (11A) of 36° ± 5°, a pitch angle in the middle of the blade of 32° ± 5° and an angle of blade tip pitch (11B) of 28° ± 5°.

Hairdressing appliance (1) according to any one of the preceding claims, characterized in that the said at least one motor (12, 13) is a brushed DC electric motor. Hairdressing appliance (1) according to any one of the preceding claims, characterized in that the blower module (6) comprises two motors (12, 13), called the upstream motor (12) and the downstream motor (13), for actuating respectively said upstream propeller (8) and said downstream propeller (9) in rotation. Hairdressing appliance (1) according to the preceding claim, characterized in that said propellers (8, 9) each comprise a hub (14, 15) which is hollow, said motors (12, 13) being at least partially housed within said hubs (14, 15). Hairdressing appliance (1) according to any one of claims 6 and 7, characterized in that said motors (12, 13) are arranged axially aligned, said propellers (8, 9) being positioned between said motors (12, 13) . Hairdressing device (1) according to the preceding claim, characterized in that it comprises an air inlet (3) and at least one air blowing outlet (4, 23), and an internal duct putting in aeraulic communication said air inlet (3) with said air blow outlet (4, 23), said motors (12, 13) and said propellers (8, 9) being arranged within said internal duct, said air inlet (3) being arranged at least partly laterally around the upstream motor (12). Hairdressing appliance (1) according to any one of the preceding claims, characterized in that the upstream propeller (8) has a number of blades (10) of between 5 and 11, and preferably equal to 9, while the The downstream propeller (9) has a number of blades (11) comprised between 3 and 10, and preferably equal to 8, said numbers of blades (10, 11) being preferentially chosen to be prime among themselves. Hairdressing appliance (1) according to any one of the preceding claims, characterized in that the blades (10, 11) of at least one of the propellers (8, 9), and preferably of each of the propellers (8 , 9), are distributed radially non-equidistantly. Hairdressing appliance (1) according to any one of the preceding claims, characterized in that the said helices (8, 9) have respective solidities of less than 1, while being preferentially greater than 0.9, and more preferentially still equal to 0.95±0.01. Hairdressing appliance (1) according to any one of the preceding claims, characterized in that the blades (10, 11) of the propellers (8, 9) are curved, and each preferably has a maximum camber of between 0.1 mm and 0.6 mm, and preferably equal to 0.2 mm ± 0.05 mm. Hairdressing appliance (1) according to the preceding claim, characterized in that each of the blades (10) of the upstream propeller (8) has a generatrix curvature which is in the opposite direction to a respective generatrix curvature of each of the blades ( 11) of the downstream propeller (9). Hairdressing appliance (1) according to any one of the preceding claims, characterized in that the helices (8, 9) are arranged so that a mean vanishing plane (P _mf ) of the upstream helix (8) is arranged at a distance (d) of between 5 mm and 10 mm, preferably between 6 mm and 10 mm, and more preferably still equal to 8 mm, from a mean plane of attack (P _ma ) of the downstream propeller (9). Hairdressing appliance (1) according to any one of the preceding claims, characterized in that it comprises a porous medium (27) arranged between the said helices (8, 9), the said porous medium (27) preferably having a porosity comprised between 30% and 90%, and more preferably between 50% and 85%. Hairdressing appliance (1) according to any one of the preceding claims, characterized in that the diameter (Di ₁ ) at the tip of the blades (10B) of the upstream propeller (8) is identical to the diameter (Di ₂ ) at the tip of blades (11B) of the downstream propeller (9).