CN220832204U - Hair styling device - Google Patents

Abstract

The utility model relates to a hair styling device, comprising two arms, wherein each arm is provided with a heating plate, and the heating plate is provided with a heating element capable of heating the heating plate. The hair styling device further comprises at least one detection means for detecting the temperature of the heating element, and an electronic circuit comprising: a) Processing means adapted to receive and process the information received from the control means relating to the temperature of the heating element, and b) at least one basic electronic switch capable of activating/deactivating the respective heating element. The hair styling device according to the utility model is characterized in that the electronic circuit further comprises at least two electronic safety switches and at least one basic electronic switch connected in series with each other. Thus, the problem of overheating of the heating element is managed in an optimal way even without thermal limiters and associated protectors capable of guaranteeing its function and relative safety.

Description

Hair styling device

Technical Field

The present utility model relates to a hair styling device; in particular, the present utility model relates to a hair straightener for styling hair provided with a safety circuit.

Background

Hair straighteners for styling hair, particularly hair straighteners for straightening or waving hair, have been in use for some time.

Today, the market demands that these hair straighteners have both the dual feature of being able to heat quickly and at the same time having excellent styling performance.

In fact, these hair straighteners are equipped with at least two heating elements, one on each of the two heating plates, and generally have very high power (from above 100 watts, even up to 400 watts, depending on the size of the plate itself, which must be heated inside the hair straightener), which allows the hair straightener itself to reach an optimal operating temperature (about 210-230 ℃) in a very short time. In this way, the hair straightener is very effective, as the user tries to give their hair the desired shape (straight or wavy) by a single treatment of the hair straightener itself.

At the same time, considering that these high powers operate on very small surfaces, which are very overheated, these hair straighteners need to be equipped with a device, such as an electronic thermostat, which is able to control the temperature of the heating element so that it does not reach too high a value, which would damage both the hair straightener and the hair of the user.

Typically, the temperature of the heating element is regulated and managed by an electronic circuit that uses a microprocessor or equivalent electronic circuit to receive temperature signals from a probe or sensor, or by measuring the increase in impedance of the heating element itself, process these temperature signals and decide when to deactivate the resistor in order to reactivate it when the temperature falls below a certain threshold again. Thus, these sensors or probes enable the electronic circuitry to know at what temperature the system is operating.

Typically, the heating element is a resistive device, which may be made by metal deposition on an alumina or equivalent ceramic substrate.

Other types of heating elements are made of conductive materials with PTC (positive temperature coefficient) characteristics, wherein the resistance increases its value in a non-linear manner with increasing temperature, and generally for this application they have a thermal equilibrium around 300 ℃ and therefore heat up slower, providing poorer heating performance (and therefore the user has to wait a little longer before reaching a suitable use temperature).

In all cases, however, it is preferable to use a sensor that measures the temperature of the heating element.

An example of a sensor in combination with these heating elements is of the NTC type, which has the property of significantly reducing its resistance with increasing temperature. This may be used in combination with resistive heating elements and PTC heating elements.

Another example of a sensor known in the art is to measure linear and positive impedance changes that certain types of resistive heating elements have, wherein the impedance changes also indirectly act as temperature sensors.

Another example of a known prior art sensor is still resistive, but is separate from the heating circuit and has the characteristics of linear and positive impedance variation; the sensor may be integrated directly into the ceramic body of the resistive heating element.

All types of temperature sensors are used with electronic control circuitry; typically, they are managed by a microprocessor or equivalent component. If for some reason the electronic control circuit is no longer able to regulate the temperature of the heating elements, these elements will continue to operate at very high temperatures, thus far exceeding the normal operating temperature of 230 ℃, without the user noticing this immediately and with the risk of damaging his hair.

To prevent this, a thermal limiter, i.e. a device that prevents the hair straightener from overheating when the electronic circuit is out of control, is generally used.

For heating elements made of electrically conductive material with PTC characteristics, the use of the above mentioned thermal limiter may not be necessary, as these types of heating elements have a thermal equilibrium at a temperature of 280-300 ℃. However, this fact, even though it alleviates the safety risk of fire or loss of safe electrical insulation, obviously does not prevent the user from not noticing the problem of lack of temperature control and therefore risks damaging the hair. Thus, in certain aspects, the solution of providing PTC elements without thermal limiters is the least convenient for the user.

A typical example of a thermal limiter is an electromechanical device that reacts to temperature, also known as a thermal fuse; this is very accurate, in practice with variable tolerances in a very narrow range, typically only about +/-2 ℃.

However, in order to ensure that the hair straightener provided to the user has excellent performance over time at a maximum temperature of about 210-230 ℃, it is desirable that the thermal fuse is able to continue to operate for a period of time without ageing and thus without losing its efficiency, otherwise there is a risk that the product will not be used due to its ageing and thus the thermal fuse will be triggered unnecessarily.

Another example of a thermal limiter is a bimetallic thermostat (which functions in a similar way to a thermostat) applied to a heating element, which uses bimetal but, once a certain temperature is reached, it preferably opens contacts, rendering the product unusable.

The bi-metallic thermostat applied to the heating element does not have the aging problems described above in connection with the use of thermal fuses, but does have the problem of high tolerances, approximately between +/-5 and +/-10 c, which is a relevant counterindication to be considered when designing hair straighteners.

European patent application No. EP 2929798A1 discloses a styling device for dual supply voltage operation comprising a body with at least one arm carrying a styling heater, wherein the styling heater comprises one or more heating electrodes for heating the styling heater. The first power input may be connected to a battery power source and the second power input may be connected to a main power source. The first and second power inputs are each coupled to at least one of the one or more heater electrodes.

The applicant of the present utility model has therefore found that the technical problem of hair straighteners currently known on the market is that, on the one hand, they require a rapid heating so that they can be used almost immediately by the user with a very short waiting time. On the other hand, in order to avoid excessive overheating, the hair straightener is required to be equipped with a thermal limiter to protect the hair straightener. However, it is also necessary to ensure that these technical restrictors are both low temperature tolerant and maintain their efficiency over time to avoid problems arising from the use of thermal restrictors that are not suitable for protecting hair straighteners.

In particular, the applicant of the present utility model has also found that the use of thermal limiters such as thermal fuses or bimetallic thermostats or of heating elements of the PTC type does not avoid the risk that the user may damage the hair when the electronic control is unable to adjust the temperature to an optimal value, since the temperature after intervention thereof reaches too high a value.

Disclosure of utility model

In a first aspect, the present utility model relates to a hair styling device.

The applicant of the present utility model has in fact surprisingly found that a hair styling device which effectively and reliably solves the above mentioned technical problems comprises a first arm, a second arm, and a hinge connecting said first arm to said second arm, such that the device can be in a closed position when said first arm and said second arm are brought into proximity with each other, and in an open position when said first arm and said second arm are moved away from each other.

The first arm has: a) At least one first heating plate adapted to heat hair when interposed between the first arm and the second arm; b) At least one first heating element adapted to heat the at least one first heating plate.

Also, the second arm is provided with: a) At least one second heating plate adapted to heat hair when interposed between the first arm and the second arm; b) At least one second heating element adapted to heat the at least one second heating plate.

At least one of the first and second arms has at least one detection device capable of detecting the temperature of the respective at least one first heating element and/or the respective at least one second heating element.

The hair styling device further comprises an electronic circuit comprising processing means adapted to receive and process information received from said detection means, and at least one basic electronic switch adapted to be activated/deactivated in dependence of said information processed by said processing means and to thereby activate/deactivate said at least one first heating element and/or said at least one second heating element.

The electronic circuit further comprises at least two electronic safety switches, namely a first electronic safety switch and a second electronic safety switch, which are connected in series with each other and in series to the at least one basic electronic switch.

The hair styling device according to the utility model is characterized in that the at least one basic switch, the first electronic safety switch and the second electronic safety switch are selected from the group comprising Triac-type (abbreviation for english definition of alternating current transistor) or SCR-type (abbreviation for english definition of silicon controlled rectifier) switches.

Thus, the hair styling device of the present utility model represents an advantageous alternative to hair styling devices known in the art, in which it is desirable to have a thermal limiter, i.e., a device that prevents the hair straightener from excessively overheating when the electronic circuit detects that the first basic electronic switch is out of control and remains in the permanently ON position. Since there is no need for such a thermal limiter, the hair styling device of the present utility model does not even need any type of thermal limiter protector, either in the case of electromechanical types, with the associated problems of excessive tolerance, or in the case of thermal fuse types, with the associated problems of having to control the ageing and efficiency loss of the thermal fuse.

In fact, the simultaneous presence of a first electronic safety switch, which is connected in series to at least one basic electronic switch, and of at least a second electronic safety switch, which is connected in series to the first electronic safety switch, makes it possible to manage overheating heating elements with high safety problems. As the intervention time of at least one of the two electronic safety switches managed by the electronic circuit will be much shorter than the time required to cause the intervention of the thermal limiter described above.

In fact, if the failure of at least one basic electronic switch and the failure of the first electronic safety switch occur simultaneously, resulting in an inability to interrupt any overheating of at least one heating element connected and managed from said basic electronic switch, the presence of the second electronic safety switch makes it possible to reestablish control of at least one heating element which will be deactivated when it exceeds a given excessive temperature. Thus, even if at least one of the basic electronic switch and the first electronic safety switch get jammed, the problem of overheating the heating element can be avoided.

In addition, the advantages of simplifying the assembly of the electronic circuit and reducing the number of components and electrical connection cables (without the need for thermal limiters and their relative protectors) are also obtained, thus also reducing the relative costs.

According to a preferred embodiment, the hair styling device is a hair styling iron.

According to a preferred embodiment, the at least one first heating plate and/or the at least one second heating plate is made of aluminium or other alloy or ceramic material.

According to a preferred embodiment, the at least one first heating element and/or the at least one second heating element is of the resistive or PTC type.

According to a preferred embodiment, said at least one detection means adapted to detect the temperature of said at least one first heating element and said at least one second heating element is a temperature probe or sensor.

According to a preferred embodiment, the temperature sensor is of the NTC type suitable for any type of heating element.

According to an alternative embodiment, the temperature sensor is a resistive sensor, which also constitutes the resistive heating element.

According to a further alternative embodiment, the temperature sensor is a resistive sensor, separate from the heating element itself, but integrated in the heating body of the resistive heating element.

According to a preferred embodiment, said processing means adapted to receive and process information related to the temperature of the heating element, information received from said detecting means (e.g. from said sensor), is a microprocessor or equivalent system having components capable of processing data and sending commands to the switch using analog or analog digital techniques.

According to a first aspect of the utility model, the at least one first heating element of the first arm is connected in parallel with the at least one second heating element of the second arm. According to a first aspect of the utility model, the first means is able to detect the temperature of said at least one first heating element of the first arm and the second means is able to detect the temperature of said at least one second heating element of the second arm.

According to a preferred embodiment of this first aspect, the electronic circuit comprises a first basic electronic switch adapted to activate/deactivate the at least one first heating element of the first arm, and a second basic electronic switch adapted to activate/deactivate the at least one second heating element of the second arm.

Thus, since at least one first heating element and at least one second heating element are connected in parallel, in a first aspect of the utility model there are two basic electronic switches, each connected to a respective heating element.

According to a preferred embodiment of this first aspect, the at least two electronic safety switches are connected in series to the first basic electronic switch and the second basic electronic switch.

Thus, since the at least one first heating element and the at least one second heating element are connected in parallel and the at least two electronic safety switches are connected to both heating elements, in the first aspect of the utility model the at least two electronic safety switches may manage the activation/deactivation of the two basic electronic switches, thereby activating/deactivating the heating of the at least one first heating element and the at least one second heating element, respectively.

According to a second aspect of the utility model, the at least one first heating element of the first arm is connected in series with the at least one second heating element of the second arm.

According to a second aspect of the utility model, there is a single detection device capable of detecting the temperature of the at least one first heating element of the first arm and the at least one second heating element of the second arm.

According to a preferred embodiment of this second aspect, there is only one basic electronic switch capable of activating/deactivating said first heating element of a first arm and said second heating element of a second arm connected in series with each other.

Thus, since the first heating element and the second heating element are connected in series, they must be turned on and off simultaneously; thus, in the second aspect of the utility model, it is sufficient that only one basic electronic switch is required, which will manage the first heating element and the second heating element connected in series (whereas in the case of the first heating element and the second heating element seen above being connected in parallel, two basic electronic switches are required, one for each heating element connected in parallel).

According to a preferred embodiment of this second aspect, the at least two electronic safety switches are connected in series to the single basic electronic switch.

Thus, since there is only one basic electronic switch, at least two electronic safety switches are connected in series to the single basic electronic switch.

The second electronic safety switch is connected in series with the first electronic safety switch regardless of whether the first heating element and the second heating element are connected in parallel or in series.

Drawings

Further characteristics and advantages of the utility model will be better highlighted by examining the following detailed description of preferred but not exclusive embodiments, illustrated by way of example and not limitation, with the aid of the accompanying drawings:

Fig. 1 is a schematic view of an embodiment of a straightener for styling hair in accordance with the present utility model;

Fig. 2 shows a first embodiment of a circuit providing a hair straightener for styling the hair shown in fig. 1;

Fig. 3 shows a second embodiment of the circuit, in which a hair straightener for styling the hair shown in fig. 1 is provided.

Detailed Description

The following detailed description refers to specific embodiments of the hair styling device of the present utility model and is not intended to limit the scope of the utility model.

In fig. 1, a hair straightener 1 is shown.

The hair straightener 1 comprises a first arm 2a, a second arm 2b and a hinge 3 connecting the first arm 2a to the second arm 2b, such that the hair straightener 1 is in a closed position when the two arms 2a, 2b are close to each other and in an open position when the two arms 2a, 2b are far from each other.

The first arm 2a is provided with a first heating plate 4a adapted to heat hair when interposed between the first arm 2a and the second arm 2b, with a first heating element 5a adapted to heat the first heating plate 4a, and with a first sensor 6a adapted to detect the temperature of the first heating element 5 a.

Likewise, the second arm 2b is provided with a second heating plate 4b adapted to heat hair when interposed between the first arm 2a and the second arm 2b, with a second heating element 5b adapted to heat the second heating plate 4b, and with a second sensor 6b adapted to detect the temperature of the second heating element 5 b.

The first heating plate 4a and the second heating plate 4b are made of aluminum or other alloy or ceramic material; the first and second heating elements 5a and 5b are of a resistive or PTC type, and the first and second temperature sensors 6a and 6b are of an NTC type, suitable for any type of heating element.

The hair straightener 1 also has an electronic circuit 11, which electronic circuit 11 comprises a microprocessor 7 adapted to receive and process information received from the sensors 6a, 6b about the temperature of the heating elements 5a, 5b. In the embodiment shown in fig. 2, the first heating element 5a and the second heating element 5b are connected in parallel. In this configuration, the electronic circuit 11 further comprises a first basic electronic switch 8a adapted to activate/deactivate the first heating element 5a, and a second basic electronic switch 8b adapted to activate/deactivate the second heating element 5b. The basic electronic switches 8a, 8b are activated/deactivated in accordance with information processed by the microprocessor 7.

The electronic circuit 11 shown in fig. 2 furthermore comprises a first electronic safety switch 9, which is connected in series with the basic electronic switches 8a, 8b, and a second electronic safety switch 10, which is connected in series with the first electronic safety switch 9. All switches 8a, 8b, 9, 10 are of the Triac type. In other embodiments, some or all of these switches 8a, 8b, 9, 10 may be of the SCR type.

Operationally, each of the first heating element 5a and the second heating element 5b is independently controlled by a first basic electronic switch 8a of the Triac type and a second basic electronic switch 8b of the Triac type, respectively, which in turn are independently operated by the microprocessor 7 upon receiving and processing the signals provided by the sensors 6a and 6b in relation to the temperature of the first heating element 5a and the second heating element 5 b. If the basic electronic switch 8a (or the basic electronic switch 8 b) fails, while the first electronic safety switch 9 fails at the same time, resulting in an inability to interrupt the possible overheating of the first heating element 5a or the second heating element 5b, the presence of the second electronic safety switch 10 allows to reestablish the temperature control of the heating elements 5a and 5 b. Therefore, even if the basic electronic switches 8a and 8b and the first electronic safety switch 9 interrupt their normal operation for any reason, the problem of overheating of the heating elements 5a and 5b can be avoided.

The embodiment shown in fig. 3 differs from the embodiment described above with reference to fig. 2 in that here the first heating element 5a and the second heating element 5b are connected in series instead of in parallel as in fig. 2. In this configuration of fig. 3, the electronic circuit 11 comprises a single temperature sensor (6 a), a basic electronic switch 8a capable of activating/deactivating the first heating element 5a and the second heating element 5 b. Furthermore, the first electronic safety switch 9 is connected to a single basic electronic switch 8a, and the second electronic safety switch 10 is connected in series to the first electronic safety switch 9. Also in this embodiment, the switches 8a, 9, 10 may be of the TRIAC type or of the SCR type.

Or instead of having a single temperature sensor 6a, it is possible to have two temperature sensors 6a,6b, the two temperature sensors 6a,6b being connected to each other, thus acting in concert as a single temperature sensor.

In operation, the first and second electronic safety switches 9 and 10 operate in the same manner as described above with reference to the circuit shown in fig. 2. Thus, if a single electronic safety switch base 8a fails, while the first electronic safety switch 9 fails at the same time, resulting in an uninterrupted subsequent overheating of the first heating element 5a and the second heating element 5b (if the electronic switch 8a is no longer able to control the temperature if it is connected in series, both heating elements 5a and 5b overheat), the presence of the second electronic safety switch 10 allows to reestablish control of the temperature of the heating elements 5a and 5 b. Also in this case, even if the single basic electronic switch 8a and the first electronic safety switch 9 interrupt their normal operation for any reason, the problem of overheating of the heating elements 5a and 5b can be avoided.

Thus, the hair straightener 1 of the present utility model represents an advantageous alternative to hair styling devices known in the art, in which it is desirable to have a thermal limiter, i.e. a device that prevents the straightener from overheating excessively when the basic electronic switch is kept in a permanently ON position. Since there is no need for such a thermal limiter, the hair styling iron of the present utility model does not even need any type of thermal limiter protector, either in the case of problems associated with excessive tolerances of the electromechanical type, or in the case of problems associated with ageing and loss of efficiency of the thermal fuse type, which must be controlled.

In fact, due to the double safety redundancy, the first and second electronic safety switches are present at the same time, which can guarantee the problem of overheating of the heating element in a safe manner.

In addition, advantages are obtained in terms of simplified electronic circuit assembly and reduced component count (without the need for thermal limiters and their connecting cables), thereby also reducing relative costs.

Of course, many modifications and variations to the disclosed preferred embodiments will be apparent to those skilled in the art, while remaining within the scope of the utility model.

For example, in other embodiments of the utility model, the detection means 6a, 6b adapted to detect the temperature of the heating elements 5a, 5b may be temperature probes instead of temperature sensors as described in the detailed description with reference to fig. 1-3.

Furthermore, in other embodiments of the utility model, the processing means are adapted to receive and process the temperature related information of the respective heating element 5a, 5b received from the detection means 6a,6 b; the processing means may be a system equivalent to the microprocessor 7 (indicated in the detailed description above with reference to fig. 2-3) and provided with components capable of processing data and sending commands to the exchange using analog or analog-digital techniques.

Therefore, the present utility model is not limited to the described preferred embodiments, which are illustrated by way of non-limiting examples only, but is defined by the following claims.

Claims (10)

1. Hair styling device (1), characterized by comprising a first arm (2 a), a second arm (2 b) and a hinge (3) connecting the first arm (2 a) with the second arm (2 b) such that the hair styling device (1) is in a closed position when the first arm (2 a) and the second arm (2 b) are close to each other and in an open position when the first arm (2 a) and the second arm (2 b) are distant from each other;

Wherein the first arm (2 a) is provided with: a) At least one first heating plate (4 a) capable of heating hair when interposed between said first arm (2 a) and said second arm (2 b); b) -at least one first heating element (5 a) adapted to heat said at least one first heating plate (4 a);

Wherein the second arm (2 b) is provided with: a) At least one second heating plate (4 b) capable of heating hair when interposed between said first arm (2 a) and said second arm (2 b); b) -at least one second heating element (5 b) adapted to heat said at least one second heating plate (4 b);

Wherein at least one of the first arm (2 a) and/or the second arm (2 b) is equipped with at least one detection device (6) capable of sensing the temperature of the respective at least one first heating element (5 a) and/or the respective at least one second heating element (5 b);

Wherein the device (1) further comprises an electronic circuit (11) comprising:

-processing means (7) adapted to receive and process information received from said at least one detection means (6) relating to the temperature of said respective at least one first heating element (5 a) and said respective at least one second heating element (5 b), and

-At least one basic electronic switch (8 a, 8 b) adapted to activate/deactivate according to said information processed by said processing means (7) and to activate/deactivate said at least one first heating element (5 a) and/or said at least one second heating element (5 b) accordingly;

Wherein the electronic circuit (11) further comprises at least two electronic safety switches (9, 10) connected in series with each other and connected in series to the at least one basic electronic switch (8 a, 8 b);

And wherein said at least one basic switch (8 a, 8 b) and said at least two electronic safety switches (9, 10) are selected from the group comprising a Triac or SCR type switch.

2. Hair styling device (1) according to claim 1, characterized in that it is a hair styling iron.

3. Hair styling device (1) according to claim 2, characterized in that the at least one first heating element (5 a) and/or the at least one second heating element (5 b) are of the resistive or PTC type.

4. Hair styling device (1) according to claim 1, characterized in that the at least one detection means (6) capable of detecting the temperature of the at least one first heating element (5 a) and the at least one second heating element (5 b) is a temperature probe or sensor.

5. Hair styling device (1) according to any of claims 1 to 4, characterized in that the at least one first heating element (5 a) and the at least one second heating element (5 b) are connected in parallel, wherein the first detection means (6 a) are adapted to detect the temperature of the at least one first heating element (5 a) and the second detection means (6 b) are adapted to detect the temperature of the at least one second heating element (5 b).

6. Hair styling device (1) according to claim 5, characterized in that the electronic circuit (11) comprises a first basic electronic switch (8 a) capable of activating/deactivating the at least one first heating element (5 a), and a second basic electronic switch (8 b) suitable for activating/deactivating the at least one second heating element (5 b).

7. Hair styling device (1) according to claim 6, characterized in that the at least two electronic safety switches (9, 10) are connected in series to the first basic electronic switch (8 a) and the second basic electronic switch (8 b).

8. Hair styling device (1) according to claim 1, characterized in that the at least one first heating element (5 a) and the at least one second heating element (5 b) are connected in series, wherein a single detection means (6) is able to detect the temperature of the at least one first heating element (5 a) and the at least one second heating element (5 b).

9. Hair styling device (1) according to claim 8, characterized in that there is a single basic electronic switch (8 a) capable of activating/deactivating the at least one first heating element (5 a) and the at least one second heating element (5 b) connected in series with each other.

10. Hair styling device (1) according to claim 9, characterized in that the at least two electronic safety switches (9) are connected in series with the single basic electronic switch (8 a).