Air heating device for a hairdryer, blowing device for a hairdryer, and hairdryer comprising said devices

An air heating device for a hairdryer includes an inner tubular body with an outer surface from which a plurality of angularly spaced, radial baffles extend to define a plurality of angular sectors, a corrugated resistive coil extending around the inner tubular body, a safety device in electrical connection with said corrugated resistive coil, a thermostat in electrical connection with the corrugated resistive coil, and an outer tubular body arranged coaxially with the inner tubular body around the corrugated resistive coil. The safety device and the thermostat are respectively housed in a first and a second angular sector, which are adjacent to each other and separated by a shared radial baffle. The corrugated resistive coil two rectilinear portions positioned at the first and the second angular sector, respectively, At least one anchoring wave is interposed between the rectilinear portions and overlies said shared radial baffle.

The present invention relates to an air heating device for a hairdryer, a blowing device for a hairdryer, and a hairdryer comprising said devices.

Therefore, the present invention finds its main application in the field of small household appliances and more precisely in the production and manufacture of the heating components to be inserted inside the blow duct of a hairdryer.

The hairdryer sector, which for several years has been poorly innovated with regard to the final product, has recently had a considerable innovative boost both from the point of view of technology and from the point of view of the design.

In particular, new conformations of blow ducts have been developed, which differ from the classic tapered tubular body and have different and more attractive geometries.

A conformation that is having particular success is the annular one, wherein the blow duct is not “trivially” delimited by a more or less cylindrical tubular duct, but extends annularly inside a chamber suitably delimited by a pair of concentric tubes.

This conformation, in addition to allowing a particular and efficient air ejection, gives the product an attractive and distinctive appearance due to the “through” light passing through the main body of the appliance.

However, a solution of this type brings along considerable problems of space, as the available volume for the housing of all the components useful for heating the air, first of all defined by the heating device, i.e. the electrical resistance, is in fact very limited.

Therefore, the object of the present invention is to provide an air heating device for a hairdryer, a blowing device and a hairdryer comprising said device, which are capable of overcoming the above-mentioned drawbacks of the prior art.

In particular, one object of the present invention is to provide an air heating device for a hairdryer, which is compact and efficient.

In addition, a further object of the present invention is to provide a hairdryer, which is particularly powerful in increasing the air flow rate.

Said objects are achieved by means of an air heating device for a hairdryer having the features of one or more of the successive claims1to10, as well as by means of a blowing device for a hairdryer according to claims11and12and a hairdryer according to claim13.

In particular, the objects of the present invention are achieved by means of an air heating device for a hairdryer comprising an inner tubular body extending along a central axis and provided with an outer surface from which a plurality of mutually angularly spaced, radial baffles extend so as to define a plurality of angular sectors.

Preferably, there is provided a corrugated resistive coil extending circumferentially around said inner tubular body, resting on said radial baffles, and defining a plurality of turns arranged in succession along the central axis.

Preferably, there is provided a safety device placed in electrical connection with said coil.

The device preferably comprises a thermostat placed in electrical connection with said coil.

Preferably, there is provided an outer tubular body made of insulating material and arranged coaxially with said inner tubular body around said corrugated resistive coil.

Preferably, the safety device and the thermostat are respectively housed in a first and a second angular sector, which are adjacent to each other and separated by a shared radial baffle.

Preferably, the corrugated resistive coil comprises a plurality of first turns provided with:two rectilinear portions positioned at the first and the second angular sector, respectively;at least one anchoring wave interposed between said rectilinear portions and overlying said shared radial baffle.

Advantageously, in this way, a space is obtained for housing the safety device and the thermostat without compromising the stability of the coil.

Preferably, moreover, the safety device and the thermostat have a respective axial overall size along said central axis (smaller than that of the inner tubular body).

The plurality of first turns preferably extends at least at said axial overall size.

Preferably, moreover, the corrugated resistive coil comprises one or more second turns located outside of said axial overall size and devoid of said rectilinear portions.

Advantageously, in this way, heat generation is maximized without compromising the volume of the heating device.

The device preferably comprises a thermistor arranged outside the inner tubular body at a third angular sector and oriented transversely to said central axis, to maximize the surface in contact with the air flow.

It should be noted that the inner tubular body extends along the central axis between a first section, in use an air flow inlet, and a second section, in use an air flow outlet.

The thermistor is preferably located in the vicinity of the second section in order to receive a flow of air heated by the corrugated resistive coil.

To allow supply of power to the thermistor and the corrugated wire, there are provided a plurality of electrical connections arranged at said first section of the inner tubular body and at least a pair of conductive tracks anchored to the inner tubular body and extending from said electrical connections up to said thermistor.

According to a further aspect of the invention, complementary but independent with respect to what has been described up to now, the objects of the present invention are achieved by means of a hairdryer comprising a handle and a main body extending transversely to said handle and defining therein a containment compartment.

Preferably, said main body extends along its main axis between a suction mouth and an air outlet defining an annular blowing nozzle.

In particular, the main body extends between a first and a second end portion.

Preferably, the first end portion has the suction mouth, and the second end portion has the air outlet defining an annular blowing nozzle.

Preferably, there is provided a blowing device housed in the containment compartment.

The blowing device preferably comprises an air heating device for a hairdryer, an electric motor and a fan.

Preferably, the air heating device comprises an inner tubular body extending along a central axis and around which a corrugated resistive coil is wound, the latter defining a plurality of turns arranged in succession along the central axis.

Preferably, the electric motor is provided with a stator body housed inside the inner tubular body of the heating device and equipped with a drive shaft rotatable coaxially with said central axis.

Preferably, the fan is fixed to a free end of the drive shaft and provided with a plurality of blades shaped so as to generate a flow of air directed toward the heating device.

Preferably, the blowing device is oriented so that said fan is interposed between said suction mouth and said inner tubular body of the heating device.

Advantageously, in this way, it is possible to obtain a hairdryer with a high coefficient of increase in the air flow rate even in the presence of a casing (or body) of the traditional type, making the device simple and inexpensive to manufacture.

According to a further aspect of the invention, the blowing device comprises a control circuit controlling said electric motor and said heating device, which is housed inside said inner tubular body of the heating device and abutted against the stator body of the electric motor.

With reference to the accompanying figures, the numeral1indicates an air heating device for a hairdryer100,200according to the present invention.

The heating device1is of the type commonly defined as “resistance” in that it comprises, in addition to a support (better described below), a resistive coil which, when an electric current passes through it, overheats so as to raise the temperature of an air flow hitting it.

In general, therefore, the air heating device1comprises a support around which at least one resistive wire is wound, which in use is hit by an air flow generated by ventilation/blowing means, operatively placed upstream, in order to raise its temperature.

With reference to the present invention, the support is defined by an inner tubular body2extending along a central axis “A” and provided with an inner surface2aand an outer surface2b, both substantially cylindrical.

The inner tubular body2extends longitudinally along the central axis “A” between a first section3aand a second section3b.

In use, that is with the device1mounted in the hairdryer100,200, the first section3ais an air flow inlet section, whereas the second section3bis an air flow outlet section.

A plurality of mutually angularly spaced, radial baffles4extend from the outer surface2bof the inner tubular body2, so as to define a plurality of angular sectors “S”.

The radial baffles4extend parallel to the main axis and, starting from the outer surface2bof the inner tubular body2, away from it along a radial direction (diverging from the central axis “A”), between a radially inner edge, engaged within the inner tubular body2, and a radially outer edge4a.

The inner tubular body2is preferably provided with a plurality of retaining portions5coupled to the radial baffles4.

More precisely, the inner tubular body2comprises, at the outer surface2b, a plurality of coupled/couplable housings, each with a respective radial baffle4so as to hold it and keep it in an upright position.

It should be noted that, in the preferred embodiment, the inner tubular body2is a single body, and the retaining portions5are formed directly thereon.

Preferably, the inner tubular body2is made of a thermal insulating plastic material, and more preferably the retaining portions5are obtained by moulding.

Instead, the radial baffles4are preferably made of an electrical insulating and thermal resistant material, for example mica or other antistatic material.

The device1further comprises a corrugated resistive coil6extending circumferentially around the inner tubular body2which, as previously mentioned, has the purpose of heating the air flow hitting it.

The coil6extends resting on the radial baffles4and defines a plurality of turns7arranged in succession along the central axis “A”.

It should be noted that, to maximize heat transfer, the resistive wire forming the coil6is shaped according to at least one predetermined waveform, which can comprise sinusoidal and/or zig-zag and/or square and/or spiral undulations, and more generally undulations of any form.

In the illustrated embodiment, each turn7of the coil extends circumferentially around the inner tubular body2according to a wavy pattern defining a succession of peaks and grooves.

Preferably, the radially outer edge4aof each radial baffle4has a toothed shape in order to define a succession of housing seats for the turns7of the resistive coil6.

In other words, a groove is formed between two successive teeth which accommodates therein the section of the turn7resting on the radial baffle4, preventing it from sliding axially.

Preferably, the turns7are sized so that an anchoring wave8, defined by at least one peak of the corrugated wire overlying the radially outer edge4a, is arranged at each radial baffle4.

Advantageously, this structure gives stability to the coil, maximizing its efficiency and, above all, guaranteeing its robustness to impacts.

In order to ensure the safety of the coil6, both from a thermal and an electrical point of view, the device1comprises a safety device9and a thermostat10placed in electrical connection with said corrugated resistive coil6.

More precisely, the safety device9and the thermostat10are arranged electrically upstream of the corrugated resistive coil6, in order to allow an interruption in the current flow before it passes through the resistive wire.

The safety device9is preferably a thermal fuse, more preferably calibrated (with temperatures from 70° C. to 260° C.) to prevent excessive temperatures in abnormal operating conditions.

The thermostat10, on the other hand, is preferably calibrated (with temperatures from 60° C. to 170° C.) to open the contact, in a reversible manner, when a temperature limit value is exceeded.

According to one of the aspects of the present invention, the safety device9and the thermostat10are respectively housed in a first “S1” and a second angular sector “S2”, which are adjacent to each other and separated by a shared radial baffle11.

More precisely, the safety device9and the thermostat10each extend along a preferential direction oriented parallel to the central axis “A”. In the preferred embodiment, the inner tubular body2has, at said first S1and/or second angular sector S2, respective slots2cfor receiving the safety device9and/or the thermostat10.

This slot allows at least part of the thickness of the safety device9or of the thermostat10to be embedded in the inner tubular body2, thus reducing its radial overall size within the respective angular sector.

It should be noted that the first “S1” and the second angular sector “S2” preferably have a greater size than the other angular sectors “S”.

In the preferred embodiment, the first “S1” and the second angular sector “S2” have the same angular size, more preferably about 45°.

The other angular sectors “5”, instead, have an angular size of about 30°.

In other words, the radial baffles4defining the angular sectors “5” are angularly equally spaced from one another, with the exception of the radial baffles4defining the first “S1” and the second angular sector “S2”, which have a different angular arrangement in order to increase the housing volume for the safety device9and the thermostat10.

According to a further aspect of the invention, in addition, the corrugated resistive coil6comprises a plurality of first turns7aprovided with:two rectilinear portions12positioned at the first “S1” and the second angular sector “S2”, respectively;at least one anchoring wave8interposed between said rectilinear portions12and overlying said shared radial baffle11.

Advantageously, in this way, it is possible to create a space sufficient to accommodate the safety device9and the thermostat10within the first “S1” and the second angular sector “S2”, without compromising either the efficiency of the device1or its robustness.

Preferably, the anchoring wave8comprises two grooves between which a peak straddling the shared radial baffle11is interposed, preferably housed between two successive teeth of the radially outer edge of the baffle.

Therefore, the rectilinear portions12define, in fact, two prismatic housings (i.e. parallelepipeds) extending along the central axis “A” outside the inner tubular body2.

It should be noted that the safety device9and the thermostat10have a respective axial overall size along the central axis “A”, preferably smaller than the axial extent of the inner tubular body2, and the plurality of first turns7aof the corrugated resistive coil6extends at said axial overall size. According to a preferred embodiment, the corrugated resistive coil6comprises one or more second turns7blocated outside of said axial overall size and devoid of said rectilinear portions12.

Advantageously, in this way, the distribution of the coil is optimized and the generation of heat is maximized.

Preferably, moreover, the device further comprises a thermistor13arranged outside the inner tubular body2at a third angular sector S3and oriented transversely to said central axis “A”.

Preferably, for the measurement to be accurate and consistent with the user's perception, the thermistor13is located near the second section3bof the inner tubular body2.

In this way, in fact, the thermistor is positioned so as to receive the air flow already heated by the corrugated resistive coil6, reducing as much as possible the delay between the user's perception and a possible control.

In this regard, it should be noted that the device1comprises a plurality of electrical connections14arranged at the first section3aof the inner tubular body2. To allow transmission of the current to the thermistor13, there is provided at least one pair of conductive tracks15anchored to the inner tubular body2and extending from said electrical connections14up to said thermistor13.

Preferably, the pair of tracks15is anchored to the inner surface2aof the inner tubular body2.

Preferably, moreover, the device1further comprises an outer tubular body16made of insulating material and arranged coaxially with said inner tubular body2around said corrugated resistive coil6, in order to protect it.

In the preferred embodiment, the outer tubular body16is also made of mica or the like, however of the same material as the radial baffles4.

Preferably, during positioning, the outer tubular body16is fitted onto the inner tubular body2.

In this regard, in order to facilitate the achievement of an assembled position, the radially outer edge of at least one part of the radial baffles4comprises an axial radial abutment shoulder 17 sized to abut against a peripheral edge of the outer tubular body16.

The heating device1, thanks to its compact and annular conformation, in use, is inserted inside a hairdryer100comprising a handle101and a main body102extending transversely to the handle (at least in use) and defining therein an annular chamber103bounded between an inner tubular wall103aand an outer tubular wall103b.

The annular chamber103has at least one outlet annular mouth104located at one of its axial ends and comprises therein a heating device1, as schematically illustrated inFIG.5.

In a further embodiment, illustrated inFIGS.6a-6b, the heating device1is used in the assembly of a ventilation (or blowing) device50for a hairdryer100,200.

This blowing device50, in fact, provides that an electric motor51shall be housed inside the inner tubular body2of the heating device1.

In particular, the electric motor51is provided with a stator body52and a rotatable rotor connected to a drive shaft53.

The stator body52is housed in the inner tubular body2. The drive shaft53is rotatable coaxially with the central axis “A” and extends axially up to a free end53aprotruding from the first section3aof the inner tubular body2.

In other words, the free end53aprotrudes from the axial overall size of the heating device1.

In this regard, in fact, the blowing device50comprises a fan54fixed to said free end53aof the shaft and provided with a plurality of blades54ashaped so as to generate a flow of air directed toward the heating device1.

In particular, the fan54faces the first section3aof the inner tubular body2and has a radial extent such that the blades at least partly face the corrugated resistive coil6.

Advantageously, in this way, it is possible to obtain an extremely compact and functional structure, in which the heating and ventilation/blowing operations are carried out in a limited space.

Preferably, moreover, the blowing device50also comprises a control circuit55for the electric motor51and/or the heating device1.

This control circuit55, in turn, is preferably housed inside the inner tubular body2of the heating device1and abutted against the stator body52of the electric motor51, which allows the overall size of the device50to be further reduced.

It should be noted that, with regard to the blowing device50as described herein and object of the present invention, the resistive coil can be of any type or shape and, although it is preferable, it is not strictly necessary for it to include the presence of the rectilinear portions for housing the safety device9and the thermostat10, which, for example, could also be positioned outside the angular sectors.

In fact, independently of the conformation of the resistive coil and the positioning of the safety device9and the thermostat10, the blowing device50can be used inside the hairdryer200schematically shown by way of example inFIGS.7a-7c.

Such a hairdryer200comprises a handle201and a main body202extending transversely to said handle201.

The main body202defines therein a containment compartment203extending along its main axis between a first203aand a second end portion203b.

The first end portion203ahas a suction mouth204. In other words, an opening is provided at the first end portion203a, which is preferably occluded by a grid205or filter mesh.

On the other hand, the second end portion203bhas an air outlet206defining an annular blowing nozzle207.

The blowing device50is housed in the containment compartment203and oriented so that the fan54faces said suction mouth204, and said second section of the inner tubular body2of the heating device1faces said outlet206.

Preferably, in order to define the annular shape of the blowing nozzle207, a section reducer208is provided, which is coaxially inserted in said outlet206of the main body202so as to delimit an annular gap.

More precisely, the section reducer208comprises at least one tubular wall208ainserted in the outlet206and partly protruding externally thereto, and at least one back wall208bvisible from the outside of the hairdryer200.

The invention achieves the intended objects and attains important advantages.

In fact, the arrangement of a coil having a plurality of turns equipped with two adjacent rectilinear portions interspersed with an anchoring wave allows the efficiency of the device to be maximized, without compromising its (mechanical) robustness.

In fact, the positioning of the fuse and the thermostat in two adjacent angular sectors makes it possible to reduce the electrical connections along the inner tubular body.

By providing an anchoring wave between the two rectilinear portions, the same are prevented from increasing the fragility of the coil, which, as is known, must guarantee remarkable resistance to impacts.

Moreover, regardless of the presence of the rectilinear portions, the arrangement of a “coaxial” heating device makes it possible to combine the motor/resistance structure, making it very easy to create a compact blowing device.

Furthermore, the use of this blowing device, which is capable of generating an annular hot air flow, can be exploited in an innovative way for the production of a hairdryer designed to generate an annular blade of air even in the presence of a containment body of the traditional type.