FR3131513A1 - STEAM HEATED STYLING APPLIANCE - Google Patents

Abstract

The invention relates to a hairdressing appliance (1) comprising at least one heating element (4) intended to come into contact with the hair as well as means for emitting steam configured to subject said hair to a flow of steam in contact with said heating element, said hairdressing appliance being characterized in that it is designed to be in an operational operating mode in which said heating element has a first surface temperature whose value is at least equal to 110°C, while said flow of steam has a mass flow rate of which the value is at least 0.5 g/min. Hairdressing appliances. Figure for the abstract: Fig. 1.

Description

STEAM HEATED HAIR STYLING APPLIANCE

The present invention relates to the general technical field of hairdressing devices, for example for domestic use, intended to ensure shaping, beautification and/or improvement of the health of hair, and more specifically to the field of hairdressing devices power tools such as hairdressing brushes, straightening brushes, detangling brushes or straighteners.

The invention relates more precisely to a portable hairdressing device comprising at least one heating element intended to come into contact with the hair as well as steam emission means configured to subject said hair in contact with said heating element to a flow of steam.

Hairdressing devices are known for subjecting the hair to a flow of water vapor, in association with mechanical and thermal treatment. This thermomechanical steam treatment is for example carried out by means of a brush comprising heating pins carried by a brushing head which is also provided with orifices diffusing steam. This emission of steam, associated with the mechanical action of brushing as well as the thermal action provided by the heating pins, facilitates the styling operation and makes it possible to improve its effectiveness, while preserving, at least to a certain extent. measurement, appearance of hair.

However, known devices do not make it possible to achieve optimal results, in particular concerning the preservation and improvement of the health of the hair as well as their beautification. In particular, known devices do not make it possible to obtain a significant improvement in the appearance of the hair, and in particular its shine and its surface condition.

The objects assigned to the invention therefore aim to propose a new hairdressing device which, while making it possible to obtain, easily and quickly, particularly satisfactory styling and hair shaping effects, significantly improves the appearance of the hair, and in particular its softness, suppleness, shine, and surface condition.

Another object of the invention aims to propose a new hairdressing device which makes it possible to significantly reduce the density of surface defects in the hair.

Another object of the invention aims to propose a new hairstyling device which makes it possible to significantly reduce the density of defects such as dark spots in the middle of scales, and/or such as raising scales at the ends of the scales.

Another object of the invention aims to propose a new hairdressing device which allows tangible beautification of the hair, with in particular a significant increase in the shine of the hair.

Another object of the invention aims to propose a new hairdressing device whose design makes it possible to subject the hair in a particularly effective manner to a flow of steam.

Another object of the invention aims to propose a new hairdressing device of particularly simple, reliable and compact construction.

Another object of the invention aims to propose a new hairdressing device whose use is particularly safe and comfortable, with a minimized risk of burns.

Another object of the invention aims to propose a new hairdressing device of light and economical design.

Another object of the invention aims to propose a new hairdressing device making it possible to simultaneously ensure, in a simple and rapid manner, disciplining of the hair, even detangling and/or shaping, and beautification of the hair. .

Another object of the invention aims to propose a new hairdressing device whose energy consumption is optimized.

The objects assigned to the invention are achieved using a hairdressing appliance comprising at least one heating element intended to come into contact with the hair as well as steam emission means configured to subject said steam to a flow of steam. hair in contact with said heating element, said hairdressing appliance being characterized in that it is designed to be in an operational operating mode in which said heating element has a first surface temperature whose value is at least equal to 110 ° C, while said steam flow has a mass flow rate whose value is at least equal to 0.5 g/min.

Other particularities 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:

is a schematic perspective view of a hairdressing device according to the invention, constituted in this case by a hairdressing brush;

is an exploded view of the hairdressing device of the ;

is a schematic perspective view of the head of the device of the preceding figures;

is a schematic top view of the head of a hairdressing device according to the invention, constituted in this case by a hairdressing brush, which differs from the device of Figures 1 to 3 essentially by a slightly different configuration ( one row on each side instead of two alternating rows) side detangling pins which frame the main brushing zone, which is identical to that of the brush in Figures 1 to 3;

illustrates in isolation, in a schematic perspective view, a single piece of plastic material which contributes to forming the head of the or that of the and of which tensor pins are part;

illustrates in isolation, in a schematic perspective view, a one-piece piece of aluminum or cast aluminum which contributes to forming the head of the or that of the , and which includes heating pins and steam pins;

is a graph schematically illustrating an example of evolution of the mass flow rate of the flow of water vapor emitted by the hairdressing device of the preceding figures over time, in a transient operating mode which follows the start of the device, then in an operational operating mode which follows the transient operating mode, the mass flow rate of the steam flow being substantially constant in the operational operating mode;

is a graph schematically illustrating another example of evolution of the mass flow rate of the flow of water vapor emitted by a hairdressing appliance according to an alternative embodiment of the invention, in a transient operating mode which follows the start of the apparatus, then in an operational operating mode which follows the transient operating mode, the mass flow rate of the steam flow varying periodically between two extreme values in the operational operating mode;

is a graph schematically illustrating density values of so-called “ class A ” surface defects (dark spots in the middle of scales) for seven series of four hairs each, said hair being healthy and washed (data represented by squares), then artificially damaged (data represented by triangles);

is a graph schematically illustrating variation values in the density of class A surface defects for a series of artificially damaged hair which has been subjected either to a thermo-mechanical treatment without steam (data represented by circles), or to a treatment thermo-mechanical with concomitant steam treatment (data represented by squares), for seven different temperature values of thermo-mechanical treatment;

is a microscopic image of a washed healthy hair;

is a microscopic image of a washed healthy hair which has been artificially degraded by 25 immersion-drying cycles with a drying time per cycle of 10 s;

is a microscopic photo of a washed healthy hair which has been artificially degraded in the same way as that of the photo in the previous figure, and which presents defects of different classes (class A: dark spot in the middle of scales, class B: semi-circular white area corresponding to detachment or lifting of scales; class C: appearance of the endocuticle following tearing of the upper parts of the scales; class D: type III cuts, parallel to the axis of the hair and due cracking of the cuticle) identified by a corresponding initial on the photo;

is a microscopic image of a hair embellished thanks to a combined supply of heat and steam according to temperature and mass flow rate of steam in accordance with the invention.

The hairdressing device 1 according to the invention is preferably portable, that is to say that at least part, and preferably the whole, of the device 1 is designed to be grasped and manipulated by hand. hand. The hairdressing device 1 is preferably a portable electrical device, intended to be connected to the electricity distribution network to be electrically powered. It is however alternatively possible, without departing from the scope of the invention, for the device 1 to carry electrical power batteries, possibly rechargeable. The hairdressing appliance 1 is preferably designed for use in a domestic setting, and is intended to ensure shaping of the hair, and/or beautification of the hair and/or improvement of the health of the hair. 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 conceivable that the hairdressing appliance 1 is designed for use by the user on the hair of a third person (or other user). Preferably, the hairdressing appliance 1 is intended for use in a domestic setting by a user (woman or man) lacking particular professional hairdressing skills. In the embodiment illustrated in the figures, the hairdressing device 1 constitutes a hairdressing brush. The invention is however not limited to a hairdressing device 1 forming a hairdressing brush, and the hairdressing device 1 can for example constitute a straightening brush, a detangling brush or a straightener, without however being outside the scope of the invention.

As illustrated in the figures, the hairdressing appliance 1 advantageously comprises a handle 2 for manual gripping, which is intended to be grasped by hand, and for example grasped, by the user, to manipulate the hairdressing appliance 1. The handle 2 extends for example longitudinally, along a central longitudinal axis X-X', between a first end from which emerges for example an electrical power cable, and a second opposite end.

The hairdressing device 1 advantageously comprises a head 3 for engaging the hair, that is to say for preferably coming into contact with the hair in order to subject it to mechanical, thermal and/or fluidic action. The head 3 is advantageously carried by said handle 2, and extends for example longitudinally, along said central axis X-X', between a rear end secured to the second end of the handle 2, and a free front end. Preferably, as illustrated in the figures, the handle 2 has a substantially elongated shape which is extended by the head 3, which is advantageously wider than the handle 2 and has for example a generally substantially oblong shape. Preferably and as illustrated, the handle 2 and the head 3 are formed, at least in part, by a single-piece main body, of the box type, for example made of plastic material. The head 3 advantageously presents, as illustrated in the figures, a front face 3A preferably provided with brushing pins 7 between and against which the hair is intended to be and to move, when using the hairdressing appliance 1 .

The hairdressing appliance 1 comprises at least one heating element 4 intended to come into contact with the hair, to transmit heat to it, as well as means for emitting steam, advantageously water vapor, configured to subject it to a flow of steam (advantageously water vapor) said hair in contact with said heating element 4.

In other words, the hairdressing appliance 1 is designed so that hair is simultaneously:
– in contact, at least locally, with said heating element 4,
– and subjected, at least locally, to a flow of steam (preferably water vapor),
during the styling operation, during which the head 3 engages said hair, for example to brush them, preferably by means of the aforementioned brushing pins 7.

The term “ steam ” must here be taken in an extensive sense and thus designates indifferently:
– a substance (preferably water) in the gaseous state, or
– said substance (preferably water) in the liquid state in the form of a mist of droplets and/or microdroplets, or
– a mixture of said substance (preferably water) in the gaseous state and of said substance (preferably water) in the liquid state in the form of a mist of droplets and/or microdroplets .

In other words, the expression " water vapor " should not be limited to its strictly scientific definition and here covers water in the gaseous state, particles of liquid water suspended in the air , or a mixture of water in the gaseous state and liquid water particles (droplets/microdroplets) suspended in the air. The term " water " can designate any liquid containing mainly water (that is to say at least 50% by weight of water, and preferably at least 80% by weight of water, even more preferably at least 95% by weight of water) and capable of transforming into steam, and thus includes distilled water, running tap water, but also different aqueous solutions containing elements cosmetics, olfactory products, etc.

Said means of emitting steam (preferably water vapor) include for example, as illustrated:
– a liquid vaporization device 5 (preferably water) for generating from liquid, preferably from liquid water, said flow of vapor (preferably water vapor) intended to be directed towards and on the hair;
– a supply device 6 for supplying liquid, preferably liquid water, to the vaporization device 5.

The vaporization device 5 comprises for example a vaporization chamber 50 provided with a liquid supply inlet 501 and at least one vapor outlet 502. Preferably and as illustrated, the vaporization device 5 also comprises a first heating device 51 designed to heat the vaporization chamber 50 and thus transform, within the vaporization chamber 50, the liquid water into water vapor. The first heating device 51 is formed for example by resistive elements capable of heating by the Joule effect (for example one or more heating elements, or thermistor(s), with a “Positive Temperature Coefficient” (PTC)), said resistive elements being advantageously in contact with said vaporization chamber 50. Said steam outlet 502 is for its part advantageously in fluid communication with the surrounding outside air, preferably permanently, preferably via at least one orifice 710 steam ejection device arranged on the side of the front face 3A, as will be described in more detail in the following. For example, said steam ejection orifice(s) 710 is(are) in fluid communication with the interior of the vaporization chamber 50 via a channeling device 52 connected on one side to the steam outlet 502 and the other audits at least one steam ejection orifice 710.

In the preferred embodiment illustrated in the figures, the vaporization chamber 50 is permanently maintained at atmospheric pressure, which avoids the need for an outlet valve, due to the absence of a rise in steam pressure within the chamber. the steam chamber 50 and the hairdressing appliance 1. Among the advantages of such a design, we can note the absence of risk of overpressure (and therefore the absence of the need to have means to prevent or manage such overpressures), as well as a reduced risk of ejection of a stream of steam at too high a temperature likely to damage and/or burn the hair. Indeed, due to the absence of pressurization of the chamber 50, the temperature of the water vapor flow advantageously does not exceed 100°C. In addition, the speed of the steam flow and the distance traveled by the latter outside the device 1 are limited due to the absence of overpressure, which contributes to limiting the risk of burning the scalp, and therefore to a greater safety for the user.

Said supply device 6 comprises for example a reservoir 60 for storing a quantity of liquid (preferably liquid water) and a pump 61 connected to said reservoir 60 and said vaporization device 5. The reservoir 60 is by removable example, that is to say it is detachable from the main body of the device 1, which makes it possible to do without an earth connection for the electrical supply of the device 1. To this end , the reservoir 60 is preferably substantially at atmospheric pressure. The use of a pump 61 associated with a tank 60 at atmospheric pressure, rather than a pressurized tank associated with a valve, also allows optimal safety of use and increased reliability in terms of flow control. Preferably, said pump 61 is a peristaltic pump, which allows very fine control of low flow rates and guarantees relatively constant flow rates.

The device 1 is therefore designed to subject the hair engaged by the head 3 to a thermo-mechanical steam treatment, according to which the hair is simultaneously subjected to:
– a mechanical action, due to the brushing carried out by the movement of the front face 3A (from which brushing pins 7 preferentially protrude) on and against the hair;
– a thermal action, by contact and/or proximity with the heating element 4, which is advantageously carried by the head 3;
– and a fluidic action, which in this case is a steam treatment, consisting of subjecting to steam (preferably water vapor) the hair engaged by the head 3 and in contact with and/or to proximity to the heating element 4, advantageously via the steam ejection orifice(s) 710/steam pins 71 which will be described in the following.

The simultaneous implementation, and advantageously combined, of these three treatments (mechanical, thermal and steam) advantageously makes it possible to beautify, and/or care for, and/or repair the hair, and advantageously also allows for shaping. hair, in particular by disciplining it, in particular under the specific conditions described in the following.

The hairdressing appliance 1 is advantageously designed to be in an operational operating mode E _N , that is to say a normal, nominal operating mode, in which the operating parameters of the hairdressing appliance 1, and possibly all the operating parameters of the hairdressing appliance 1, are, in the absence of positive intervention from the user, substantially constant, or do not vary over a large amplitude, or even vary automatically according to a periodic pattern (sinusoidal or slotted for example) which can correspond for example to a pulsed steam flow. In other words, the operational mode of operation E _N corresponds to a stationary, cruising regime of the hairdressing device 1. Before being in the operational mode of operation E _N in question, the device 1 is for example designed to be in a transient operating mode E _T during which one, or more, or all, the operating parameters of the hairdressing appliance 1 evolve, preferably continuously and gradually, until reaching their nominal values corresponding to the aforementioned operational mode of operation E _N.

Thus, when starting up the device 1, which corresponds for example to a power supply of the latter (preferably controlled by a switch), the device 1 is first of all in the transient operating mode E _T , during which the heating element 4 gradually rises in temperature, as do the dedicated organs of the water vapor emission means (first heating device 51). The transient operating mode E _T is then followed by the operational operating mode E _N , in which the device 1 remains until it is for example turned off (end of the power supply) by the user . The transition from transient operating mode E _T to operational operating mode E _N is preferably carried out automatically, without positive intervention from the user, who can however be warned of reaching operational operating mode E _N by any means suitable signaling (light/or sound signal, steam jet, etc.). This ensures optimal operation of the hairdressing device 1 without having to request any intervention from the user. For example, the device 1 is in the operational operating mode E _N after a predetermined time has elapsed from the start-up (power supply) of the device 1. The predetermined time in question , which may possibly depend on certain technical characteristics of the device 1 (electrical power for example) is advantageously between 10 s and 60 s, without this range being of course limiting. Alternatively, said predetermined duration could be replaced or supplemented by a measurement of the temperature of the vaporization chamber 50 in order to ensure that the latter is at a temperature guaranteeing vaporization of the liquid.

According to the invention, when the device 1 is in the operational operating mode E _N , the heating element 4 has a first surface temperature (that is to say a surface temperature) whose value is at less equal to 110 ° C, while said flow of water vapor has a mass flow rate whose value is at least equal to 0.5 grams per minute (g/min).

This means that in the operational mode of operation in question, the surface of the heating element 4, which is intended to come into contact with the hair when the latter are engaged by the head 3, has a surface temperature, corresponding at said first surface temperature, the value of which is greater than or equal to 110°C. Simultaneously, the flow of water vapor emitted by the hairdressing appliance 1, preferably at the level of the head 3, has a mass flow rate whose value is greater than or equal to 0.5 g/min.

Depending on the variant of the , in the operational operating mode E _N , the value of the mass flow corresponds to a substantially constant, unique non-zero value. In other words, the device 1 is advantageously provided with a control system configured to maintain said substantially constant, fixed mass flow rate, throughout the duration during which said device 1 is placed in operational operating state E _N by said control system. In other words, during operational operation E _N, that is to say during the stationary regime or cruising regime of the device 1, the user benefits from a constant and continuous steam flow, as long as the device is supplied with electrical energy and as long as the tank 60 still contains liquid to be vaporized.

According to an alternative variant, illustrated in , and which corresponds for example to a pulsed steam flow, the value of said mass flow rate is on the contrary variable in the operational operating mode E _N , and can for example alternately affect a minimum value (which can be zero) or a maximum value _, and preferably in a cyclical, periodic manner, according to sequences of predefined durations. In this scenario, the value of said mass flow rate corresponds to an average value, which is less than the maximum value Vmax but greater than the minimum value Vmin.

The aforementioned mass flow rate is advantageously determined by calculating the difference in mass of the tank 60 for a predetermined duration in operational operating mode E _N. In other words, weighing and time measurement are advantageously used to determine the mass flow rate. The mass and the mass difference of the tank 60 can be determined easily and precisely with common weighing instruments, by carrying out several measurements, the results of which are for example averaged. In practice, the tank 60 filled with liquid (preferably water) is weighed. The balance is then tared before removing the reservoir 60 from the balance plate. Then, after the test (device 1 operating in operational operating mode E _N for a predetermined duration, for example equal to two minutes), the tank 60 - which now contains less water - is weighed again on the already tared balance . This therefore makes it possible to measure the difference in weight/mass before and after the test as a negative value. Of course, in this case we will use a balance adapted to differential weighing, allowing a negative differential value to be measured, which is the case with most laboratory balances available. The use of differential weighing as described above, if it proves to be particularly simple and practical, is of course not the only possibility for determining the mass flow and we can use methods implementing other types sensor. Finally, it should be noted that for a liquid such as water, whose density is known and constant, a measurement of the mass reflects a measurement of the volume. Therefore, a measurement of the mass of liquid water moved by a pump in a given time (mass per unit time) is also equivalent to a measurement of the flow rate (volume per unit time) of the pump. In the case where, in operational operating mode E _N , the steam flow is pulsed, so that said mass flow varies in a cyclical, periodic manner, for example in a slotted pattern, it is possible to measure an average value if necessary. and/or for example exclude from the measurements periods of time corresponding substantially to an absence of flow.

The use of the specific temperature / flow rate set out in the above leads to remarkable results, particularly in terms of beautifying the hair, and more particularly in terms of reducing defects and improving shine, as will emerge in more detail. of what follows.

Preferably, in the operational operating mode E _N , said value of said first surface temperature of the heating element 4 is at least equal to 120°C, and is advantageously between 120°C and 200°C. Even more preferably, in the operational operating mode E _N , the value of said first surface temperature is between 130°C and 170°C, preferably between 140°C and 160°C, for example substantially equal to 150°C. °C.

In the operational operating mode E _N , the value of said mass flow rate is advantageously between 0.5 g/min and 3 g/min, and even more preferably between 0.5 g/min and 1.1 g/min, and is for example substantially equal to 0.8 g/min. Beyond the advantages conferred by such a mass flow rate of steam on the appearance of the hair, as will be detailed subsequently, such a flow rate range guarantees a very interesting autonomy for the hairdressing device 1 without having to equip it with a 60 tank that is too large. Thus, such a flow rate does not consume too much liquid from the reservoir so as to provide sufficient autonomy to allow a user to carry out at least one, or even several hairstyling cycles without having to refill the reservoir 60.

Particularly preferably, very convincing results have been obtained when, in the operational mode E _N , the value of said first surface temperature is equal to 150 °C ± 20 °C, preferably 150 °C ± 10 °C. C, in association with a mass flow rate of water vapor whose value is equal to 0.8 g/min ± 0.3 g/min.

In order to guarantee a substantially constant and systematic result, the hairdressing appliance 1 is designed so that, in the operational operating mode E _N , the values of said first surface temperature of the heating element 4 and mass flow rate of the steam flow ( preferably water vapor) are advantageously fixed, that is to say they are preferably not modifiable, in particular by the user. In other words, the hairdressing appliance 1 is advantageously devoid of adjustment means making it possible to set or adjust one and/or the other of said values of said first surface temperature and mass flow rate of the steam flow of water. This makes it possible to offer the user a hairdressing device 1 perfectly optimized to offer him the best care, the best appearance, for his hair, and in particular their softness, their flexibility, their shine, as well as their surface condition. In addition, the hairdressing device 1 can thus be used optimally by a user without any particular knowledge in the matter of hair care or beautification.

Advantageously, during the transient operating mode E_T, the mass flow rate of the water vapor flow varies, with for example, after the start of the device 1 (which occurs at time t₀in the examples of the graphs of Figures 7 and 8), a significant flow rate during a predetermined period (spurting (“spurting”)burst» in English) of initial steam with a mass flow value of approximately 1.2 g/min between times t₁and t₁+ 15 s in the example of the graph of the and between moments t₁and t₃in the example of the ), followed by an abrupt decrease to a mass flow value substantially zero (between times t₁ + 15 s and t₁+ 20 s in the example of the graph of the ), then a sudden rise to a value which is preferably substantially constant, stable, corresponding to the operational mode of operation E_NOT(0.8 g/min from time t₁+ 20 s in the example of the graph of the , or between 0.5 g/min and 1 g/min from time t₃in the example of the ). The duration which separates, in the examples of Figures 7 and 8, the start-up at time t₀of device 1 (power on) and the gushing (“burst") of steam at time t₁may depend on certain technical characteristics of the device 1 (electrical power of the first heating device 51 for example) and is advantageously between 10 and 60 seconds, without this range being of course limiting.

Like the value of the mass flow rate of the steam flow, the value of said first surface temperature of the heating element 4 preferably also varies during the transient operating mode E _T , and preferably increases gradually, for example until reaching said value at least equal to 110°C corresponding to the operational operating mode E _N.

The invention has thus made it possible to demonstrate that the simultaneous supply of heat and steam (preferably water vapor), with the specific values of temperature and mass flow retained and exposed in the above, makes it possible to reduce significantly the number of surface defects of the hair, on the scales of the latter. The hair, due to this reduction in the number of defects, thus presents a smoother surface, which reflects the light more homogeneously, in the manner of a specular reflection, which makes the hair appear shinier. Due to this reduction in defects, the hair also has fewer points of attachment, that is to say, it is less likely to cling to each other and appears sensorially softer.

The invention is in particular reflected by experimental work which can be summarized as follows.

Experimental work No. 1

In order to quantify the simultaneous action of heat and steam (preferably water vapor), under the aforementioned conditions, on the surface condition of hair, a sample of healthy, washed hair has all the first been artificially degraded to present defects. To this end, the healthy, washed hair in question was artificially damaged through immersion-drying cycles in accordance with the artificial degradation protocol described in the work of Gamez-Garcia ( M. Gamez -Garcia. The cracking of h uman h air cuticles by cy clical thermal stresses . Journal of the Society of Cosmetic Chemist s , 153 ( June ) : 141-153, 1998. ISSN 00379832 ) with a number of immersion-drying cycles which amounts to 25 , and a drying time per cycle of 10 s.

There is a microscopic photograph of said healthy, washed hair, before degradation according to the aforementioned protocol. Figures 12 and 13 are microscopic photographs of the same hair after degradation according to the aforementioned protocol. The images in Figures 11 to 13 were obtained using a digital microscope referenced VHX-2000 from the company Keyence France, 1 place Costes et Bellonte, 92270 Bois-Colombes (France).

We see, on healthy and washed hair ( 1) on the one hand, then degraded (figures 12 and 13) on the other hand, different defects which can be classified according to the following four categories:
– class A: dark spots in the middle of the scales;
– class B: semi-circular white areas, generally located mainly at the ends of the scales, and corresponding to detachment or lifting of scales;
– class C: appearance of the endocuticle following removal of the upper parts of the scales;
– class D: type III cuts, parallel to the axis of the hair and due to cracking of the cuticle.

Class A and B defects are the most common and most visible.

Class A defects were quantified for 7 series of 4 healthy, washed hairs which had undergone artificial damage according to the protocol mentioned above. The graph of the represents the density of defects χA (in %) for the 7 series of 4 hairs in question, each series being referenced Si, with i = 1 to 7. The data relating to healthy and washed hair (before damage) are represented by squares , while data for damaged hair is represented by triangles.

The defect density χA is determined as follows:
– a photo of the hair concerned is captured by a high-resolution digital microscope equipped with an optical zoom lens with a maximum magnification of 5000, for example the digital microscope referenced VHX-2000 from the aforementioned Keyence France company;
– the defect density χA is estimated by processing the image thus obtained, using a computer program for detecting and quantifying defects.

The image processing program in question makes it possible to calculate the density χ _A by determining the total number of pixels N of the image corresponding to class A defects (dark spots), compared to the total number of pixels N _Z of the image in question, according to the following formula:
χ _A = N / N _z
where N is the total number of pixels belonging to class A defects and N _z is the total number of pixels in the image.

As shown in the graph of , the density of class A defects increased significantly after the hair was artificially damaged as described above.

The degraded hair corresponding to the image in Figures 12 and 13 and the graph in (data represented by triangles) are then divided into two groups, namely group no. 1 which is subject to a first beautification protocol (protocol no. 1), and group no. 2 which is subject to a second protocol embellishment (protocol no. 2). These beautification protocols are as follows.

Protocol not ° 1 : treatment thermo- mechanical without steam

A thermo-mechanical treatment is applied to the hair of group no. 1 using a steam straightener type device, the steam emission function of which has been deactivated. The treatment applied consists of three passes of the straightener on straight hair (for example using a 400 g mass attached to one end of the hair while the other end is attached to a fixed frame), at a speed of 20 mm/s, over substantially the entire length of the samples.

This three-pass treatment is repeated for different treatment temperatures, varying from 100°C to 200°C.

Protocol no. 2 : treatment thermo -mechanical with flow of steam

Treatment No. 2 consists of subjecting the hair of group No. 2 to a thermo-mechanical treatment with steam carried out using a steam straightener whose mass flow rate of steam is set at approximately 2 g/min.

The treatment applied consists of three passes of the straightener on straight hair (for example using a 400 g mass attached to one end of the hair while the other end is attached to a fixed frame), at a speed of 20 mm/s, over substantially the entire length of the samples.

This three-pass treatment is repeated for different treatment temperatures, varying from 100°C to 200°C.

Results of experimental work No. 1

The evolution τ _A of the class A defect density is calculated according to the following formula:
τ _A = (χ _Av - χ _Ap ) / χ _Av
where χ _Av is the density of class A defects of the samples before the aforementioned thermo-mechanical treatment, calculated according to the method explained above, while χ _Ap is the density of class A defects of these same samples after they have undergone the aforementioned thermo-mechanical treatment.

The results obtained for each of the protocols n°1 and n°2 mentioned above are summarized by the graph of the , from which it appears that the addition of steam allows, as long as the temperature is at least substantially equal to 110°C, a very significant and surprising reduction in class A defects, reflecting the existence of a synergistic effect heat and steam.

Experimental work No. 2

Other tests were also carried out, this time not on hair taken in isolation as in the tests of experimental work No. 1 mentioned above, but on strands of hair whose mass is approximately 4 g.

As part of these tests on strands of hair, the strands concerned underwent, as in the case of the tests previously described in experimental work no. 1, a process of artificial degradation by immersion-drying cycles in accordance with the work of Gamez -Garcia described in the aforementioned publication ( M. Gamez -Garcia. The cracking of human hair cuticles by cyclical thermal stresses. Journal of the Society of Cosmestic Chemists , 153 ( June ) : 141-153, 1998. ISSN 00379832 ). The number of immersion-drying cycles implemented this time amounts to 30, while the drying time per cycle this time amounts to 2 min.

The strands degraded according to the artificial degradation protocol described above were then subjected to a thermo-mechanical treatment with steam using a device 1 in accordance with the invention, which in this case forms a brush such as that illustrated in the figures. The treatment applied consisted of 15 or 30 passes of the brush at a speed of 20 mm/s over the entire length of the wick samples, which are tensioned (for example by means of a 400 g mass attached to one end of the wick). the wick while the other end is attached to a fixed frame). The value of said first surface temperature of the heating element 4 amounts to 160°C, while the mass flow rate of steam is established at 0.8 g/min.

For each strand of hair, a gloss measurement was carried out using a GL200 reference gloss meter from the company Courage+Khazaka electronic GmbH, Mathias-Brüggen-Str. 91 – 50829 Köln (Germany). The operating principle of such a gloss meter is based on light reflection:
– a beam of white parallel light is created by LEDs in a probe head and sent via a mirror onto the surface of the wick with an incidence of 60°;
– a first sensor evaluates the reflectance of the directly reflected light at 60°, while a second sensor evaluates the diffuse reflectance of the light at 90° (i.e. perpendicular to the surface of the wick).

Gloss measurements were thus carried out on:
– strands washed before artificial degradation;
– the degraded locks before thermo-mechanical steam treatment using device 1;
– the degraded locks after they have undergone the thermo-mechanical steam treatment with 15 brush passes;
– the degraded locks after they have undergone the thermo-mechanical steam treatment with 30 brush passes;

Each gloss measurement was repeated 3 times, and consisted of recording 10 measured values, the average of which was calculated.

Results of experimental work No. 2

The results are presented in Table 1 below (expressed in “ glossymeter units ” correlated to the standard gloss units (“ Gloss Units ” GU) of the ISO2813/ASTM D523 standards).

It appears from table 1 above that the thermo-mechanical steam treatment implemented with a combination of 160 °C / 0.8 g/min makes it possible to obtain an average shine value higher not only than that of damaged hair, but also greater than that of hair washed before degradation, demonstrating a surprising, synergistic and marked effect of beautification of the hair, thanks to the combined effect of heat and steam in the value ranges retained by the invention. It also appears from Table 1 that the average gloss value is substantially identical between the wick treated 15 times and the wick treated 30 times, which shows another advantage of the synergistic effect between heat and steam: it is not necessary to multiply the number of passes to improve the shine of the hair.

Advantageously, the brushing pins 7 which project from the front face 3A of the head 3 include at least:
– heating pins 70, represented separately by the , which contribute to forming said heating element 4, that is to say that said heating element 4 advantageously includes said heating pins 70, and is preferably formed by said heating pins 70, and
– steam pins 71 each integrating a steam ejection orifice 710 connected to a source of steam (preferably water vapor), which is formed for example by the vaporization device 5 and the supply device 6 associated described in the above.

Said steam pins 71 thus contribute to forming said steam emission means (preferably water vapor). To this end and as explained previously, each steam ejection orifice 710 is advantageously in fluid communication with the interior of the vaporization chamber 50 via the channeling device 52. The steam pins 71 thus assume, in in addition to their mechanical brushing function, a steam sprayer function, that is to say that each steam pin 71, with its steam ejection orifice 710, advantageously forms a steam projection nozzle (preferably of water vapor). Thus, thanks in particular to the steam pins 71, the fluid treatment of the hair (supply of steam via the steam ejection orifice 710 of the steam pins 71) is advantageously combined with a mechanical treatment of the hair, under the effect a resistive force generated by the hair against the steam pins 71. The term “ combined ” is understood here in the sense of simultaneous performance of said fluidic and mechanical treatments on the same area of hair. Thus the same portion of strand of hair will undergo simultaneously, that is to say concomitantly, both a fluid treatment and a mechanical treatment. This allows you to obtain a “double” action combined and concentrated on the same area of hair. This makes it possible to increase the effectiveness of the treatment, and to obtain excellent results in terms of hair styling, beautification and hair care, while minimizing the number of necessary passes of the hair styling device 1 against the hair.

In other words, in this preferred embodiment, the surface temperature of the heating pins 70 corresponds to the first aforementioned surface temperature, the value of which in operational operating mode E _N is at least equal to 110 ° C, while the steam flow (preferably water vapor) whose mass flow value is at least equal to 0.5 g/min escapes through the steam ejection orifices 710 of the steam pins 71. This mode of realization is particularly advantageous because it allows a thermo-mechanical steam treatment to be applied to the hair in an optimal and particularly effective manner. The use of pins 70, 71 to heat and diffuse the steam, in addition to the brushing function that they naturally provide, makes it possible to best diffuse the steam within the strands of hair while ensuring optimal heat exchange. .

Preferably, the steam pins 71 also play the role of heating pins, in addition to their steam diffusion function. In other words, the steam pins 71 contribute in this advantageous embodiment to forming both the heating element 4 and the steam emission means. Thus, thanks to said steam pins 71, the fluid treatment of the hair (supply of steam via the steam ejection orifice 710 of the steam pins 71 contributing to forming the steam emission means) is, more advantageously still combined not only with a mechanical treatment of the hair, under the effect of a resistive force generated by the hair against the steam pins 71 as mentioned previously, but also with a thermal treatment of the hair (supply of heat by the steam pins 71 contributing to forming the heating element 4). Thus the same portion of a strand of hair will undergo simultaneously, that is to say concomitantly, both a fluid treatment, a mechanical treatment, and a heat treatment. This allows you to obtain a “triple” action combined and concentrated on the same area of hair. This makes it possible to further increase the efficiency of hair treatment by the hairdressing apparatus 1, and thus to obtain even better results in hair styling, beautification and hair care, while further minimizing the number of necessary passages of the hairdressing appliance 1 against the hair.

Preferably, the steam pins 71 come from one piece with the heating pins 70, that is to say that in this case the steam pins 71 and the heating pins 70 are advantageously formed by a single piece of a alone. For example, the steam pins 70 and heating pins 71 are formed by a first one-piece part 700 (shown in isolation on the ) which is made of metal, for example aluminum or cast aluminum, and which is advantageously obtained by molding and/or machining a primary block of metal (preferably aluminum or cast aluminum). Advantageously, the heating pins 70, as well as the steam pins 71, are anodized, to allow them to maintain a smooth surface even when their temperature is high. Preferably, said first one-piece piece 700 made of aluminum or cast aluminum which forms the heating pins 70, as well as advantageously the steam pins 71, is placed in contact with a second heating device 40, formed for example by resistive elements capable of heating by the Joule effect, said resistive elements being in contact with said first one-piece part 700 (from which the heating pins 70 and preferably the steam pins 71 come) to heat the latter at least by thermal conduction. The second heating device 40 can be formed, for example, by one or more resistive elements capable of heating by the Joule effect (for example one or more heating elements, or thermistor(s), with a “Positive Temperature Coefficient” (PTC) ). Preferably, as in the embodiment illustrated in the figures, the second heating device 40 of the heating element 4 is distinct from said first heating device 51 of the vaporization chamber 50.

Advantageously, each of said heating pins 70 and/or said steam pins 71 has, in cross section, a substantially oblong shape, as illustrated in the figures. Thanks to this oblong shape, which gives the heating pins 70 a substantially flattened, leg-shaped shape, the heat exchange with the hair is optimized since the wider than long shape of the heating pins 70 gives a maximum exchange surface during of the passage of hair against the pins. As explained previously, the steam pins 71 also preferably play the role of heating pins, so that in this case it is preferable that they also have a substantially oblong shape in cross section, preferably substantially similar to that of the pins heating 70.

In any case, each steam pin 71 preferably has, as illustrated in the figures, a substantially flattened shape with two opposite faces, separated by the thickness of the steam pin 71, said steam ejection orifice 710 opening out on at least one of said two opposite faces, and preferably on said two faces, in which case the steam is projected on each side of the steam pin 71, which makes it possible to improve the diffusion of the steam within the wicks of hair. Thanks to this specific arrangement of the steam ejection orifice 710, which opens onto at least one of the faces of the steam pin 71, that is to say substantially perpendicular to the axis of longitudinal extension of the steam pin 71 in question, the steam comes out of the steam pin 71 with an incidence which is substantially parallel to the average plane of the front face 3A, which not only makes it possible to reduce the risk of burning the scalp during use , but also ensures a particularly effective projection of water vapor since it allows the strands of hair to be treated at their height. In order again to improve the diffusion of steam within the hair, in particular with a view to subjecting strands of hair to the flow of steam over their entire height, each steam ejection orifice 710 is preferably provided on at least half , and preferably over at least two thirds of the height of the steam pin 71 which integrates it.

Preferably and as illustrated in the figures, the head 3 of the hairdressing appliance 1, and in particular the front face 3A of said head 3, has a plane of symmetry, which is advantageously parallel to or coincides with the axis central longitudinal X-X'. Such an advantageously symmetrical construction makes it possible to obtain a hairdressing device 1 which can be used in any direction on the hair, thus forming an advantageously ambidextrous device 1, usable both by a user with the right hand or the left hand. , but also on the left side or on the right side of the user's head while advantageously maintaining an identical relative movement / treatment gesture: typically from the root to the tip of the hair. Such a symmetrical arrangement also contributes to simplifying the industrial manufacturing of the hairdressing appliance 1. Advantageously, the brushing pins 7, of which the heating pins 70 and preferably the steam pins 71 are part, can be distributed on the front face 3A according to a distribution pattern which has a central plane P of symmetry passing through said steam pins 71. According to this characteristic, the steam pins 71 are arranged substantially in the center of the front face 3A, which presents various additional advantages. A first advantage lies in the safety of use: an emission of steam localized in the center of the front face 3A makes it possible to limit the risk of burns. Another advantage lies in the fact that the water vapor can act more effectively on the hair because it can escape less easily than if it were emitted from the periphery of the head 3.

Advantageously, said brushing pins 7 also include tensor pins 72, shown in isolation on the , and which allow, in cooperation with the other brushing pins (including the heating pins 70 and the steam pins 71), to tighten the hair engaged by the head 3 in order to press them laterally on and against the heating pins 70 and / or the steam pins 71, thus allowing better heat exchange as well as a better supply of steam to the strands of hair concerned. Advantageously, each of said tensor pins 72 has substantially a shape of revolution, with for example a substantially frustoconical main body which rises between a base and a top, the latter possibly being advantageously provided with an enlarged and rounded head, substantially spheroidal. Such geometry helps protect the scalp and obtain an optimal detangling effect. Preferably, said tensor pins 72 are formed by the same second single piece 701, illustrated in isolation by the , for example in plastic, and even more preferably in hard plastic, of the polyurethane or PPS (polyphenylene sulfide) type, advantageously polished, which has a particularly smooth surface while being resistant to high temperatures. The choice of a plastic material also makes it possible to benefit from lower thermal conduction properties than that of a metal such as aluminum or cast aluminum, which advantageously forms the first one-piece part 700 from which the heating pins 70 come. This allows the tensor pins 72 to also play the role of thermal insulator, in which case said tensor pins 72 advantageously assume the function of insulating pins. To this end, said tensioning pins 72 are preferably higher than said steam pins 71 and/or are higher than said heating pins 70, so that they make it possible to keep the heating pins 70 and the steam pins 71 at a distance. of the scalp, when using the hair styling device 1, thus limiting the risk of burns. Indeed, due in particular to the thermally insulating nature of the material of the tensor pins 72, the latter present, in the operational mode E _N , a second surface temperature (that is to say a surface temperature) whose value is advantageously lower than that of said first surface temperature. Advantageously, the value of said second surface temperature is compatible with contact with the scalp, that is to say it is low enough not to cause burns and/or any discomfort.

Preferably, the second one-piece piece 701 from which the tensor pins 72 come and the first one-piece piece 700 from which the heating pins 70 come (as well as preferably the steam pins 71) are superposed, with the second one-piece piece 701 forming the tensor pins 72 placed on and against the first one-piece piece 700 forming the heating pins 70, the latter projecting through openings 701A provided through the second one-piece piece 701.

In order to promote the mechanical tensioning of the hair, the tensor pins 72 are advantageously distributed in a specific manner relative to the heating pins 70, of which the steam pins 71 preferably form part, in accordance with the embodiment illustrated in the figures. Thus, as illustrated in the figures, a first plurality 70A of said heating pins 70 is distributed on the front face 3A along at least a first primary row R1, which extends for example longitudinally along a first axis X1-X1' substantially parallel to the 'central longitudinal axis 'substantially parallel to the central axis X-X'. As illustrated, said first primary rows R1 and secondary R2 are preferably substantially parallel and offset longitudinally so that the heating pins 70 and tensor pins 72 of said first primary rows R1 and secondary R2 are not aligned in a transverse direction Y-Y' substantially perpendicular to the central axis X-X'. In other words, the heating pins 70 and tensor pins 72 are offset transversely. Said first primary rows R1 and secondary R2 are preferably adjacent, that is to say they extend next to each other. Thanks to this longitudinal offset, the hair is stretched by the alternation of the tensor pins 72 and the heating pins 70, which allows the hair to be pressed onto the heating pins 70, thus increasing the exchange surface. This makes it possible to properly carry out the heat treatment described above and partly contributes to the beautification and care of the hair. Preferably, in order to further increase this tensioning effect, the first primary rows R1 and secondary R2 are offset longitudinally so that the pins 70, 72 of said first primary rows R1 and secondary R2 are arranged in a staggered manner. Advantageously, and in accordance with the embodiment illustrated in the figures, said first plurality 70A of said heating pins 70 is distributed on the front face 3A according to a plurality of primary rows R1, R1', R1'', R1''' (including said first primary row R1), while said first plurality 72A of said tensor pins 72 is distributed on the front face 3A according to a plurality of secondary rows R2, R2', R2'', R2''' (including said first secondary row R2), said primary rows R1, R1', R1'', R1''' and secondary rows R2, R2', R2'', R2''' being arranged alternately. This means that two primary rows of heating pins 70 are advantageously separated by a secondary row of tensor pins 72, and conversely that two secondary rows of tensor pins 72 are advantageously separated by a primary row of heating pins 70. This alternating arrangement of the pins heating pins 70 and tensor pins 72, and preferably with a longitudinal offset as discussed previously, makes it possible to tension the hair engaged by the head 3 in an optimal manner, thus improving the thermal transfer and the diffusion of steam within the hair, which helps to further improve the desired embellishment effect.

Advantageously, a second plurality 72B of said tensor pins 72 as well as a first plurality 71A of said steam pins 71 are aligned to form a mixed row R3 within which said tensor pins 72 and said steam pins 71 are arranged alternately, c 'that is to say that in the longitudinal direction materialized by the central axis X-X', each tensor pin 72 of the mixed row R3 is adjacent to at least one steam pin 71 of the mixed row R3, while vice versa each steam pin 71 of the mixed row R3 is adjacent to at least one tensor pin 72 of the mixed row R3. This configuration makes it possible to confine the jets of steam coming from each steam pin 71, on each side of the latter, and thus to promote optimal diffusion of steam through the strands of hair engaged by the head 3. Preferably, as illustrated in the figures, the mixed row R3 is central, that is to say it is aligned with the central longitudinal axis X-X'. Thus, the plane P of central symmetry preferentially crosses the mixed row R3 which is included at least partly in the plane P. As explained previously, this makes it possible to apply the steam treatment to the center of the head 3 of the brush but also to properly confine the steam to the center of the brush, thus limiting its losses, and therefore guarantees optimal application of the steam treatment plus heat treatment couple according to the ranges of the invention, as described previously.

In the preferred embodiment illustrated in the figures, said plurality of secondary rows R2, R2', R2'', R2''' comprises, in addition to said first secondary row R2 which extends longitudinally along the second axis X2-X2', a second secondary row R2', which extends for example along a third axis X3-X3', said first and second secondary rows R2, R2' being arranged on either side of said mixed row R3. Preferably, said mixed rows R3, first secondary row R2 and second secondary row R2' are offset longitudinally so that their pins are not aligned in the transverse direction Y-Y', and are preferably arranged staggered as illustrated, which allows you to press the hair against the steam pins 71 and thus optimize the transfer of heat and steam. In the particular embodiment illustrated in the figures, said plurality of primary rows comprises, in addition to said first primary row R1, a second primary row R1' which is arranged symmetrically to said first primary row R1 with respect to said central plane P of symmetry and which extends longitudinally along a fourth axis X4-X4'. Said plurality of primary rows also preferably comprises a third primary row R1'' which extends longitudinally along a fifth axis X5-X5' substantially parallel to said central longitudinal axis X-X'. As illustrated, said fifth axis X5-X5' is further away from said central longitudinal axis X-X' than is the first axis X1-X1'. Said plurality of primary rows further comprises a fourth primary row R1''' which is arranged symmetrically to said third primary row R1'' with respect to said central plane P of symmetry, and which extends longitudinally along a sixth axis X6 -X6'. Furthermore, as illustrated in the figures, said plurality of secondary rows also comprises a third secondary row R2'', which extends for example along a seventh axis X7-X7' advantageously interposed between said first axis X1-X1' and fifth axis X5-X5'. Symmetrically, said plurality of secondary rows also comprises a fourth secondary row R2''', which extends for example along an eighth axis X8-X8' advantageously interposed between said fourth axis X4-X4' and sixth axis X6-X6'. Advantageously, the primary and secondary rows are alternated, and are also preferably offset longitudinally in pairs, which allows excellent heat exchange and efficient penetration of the steam flow within the strands of hair engaged by the head 3.

Ultimately, the invention allows, by combining specifically selected parameter values (surface temperature of the heating element 4 and mass flow rate of the water vapor flow), as well as preferably a specific distribution of pins assuming different functions, to obtain truly remarkable results in hair beautification.

Claims (16)

Hairdressing apparatus (1) comprising at least one heating element (4) intended to come into contact with the hair as well as steam emission means configured to subject said hair in contact with said heating element (4) to a flow of steam. , said hairdressing appliance (1) being characterized in that it is designed to be in an operational operating mode (E _N ) in which said heating element (4) has a first surface temperature whose value is at least equal at 110°C, while said steam flow has a mass flow rate whose value is at least equal to 0.5 g/min. Hairdressing apparatus (1) according to the preceding claim characterized in that in the operational operating mode (E _N ), said value of said first surface temperature is at least equal to 120 °C. Hairdressing apparatus (1) according to the preceding claim characterized in that in the operational operating mode (E _N ), said value of said first surface temperature is between 120 °C and 200 °C. Hairdressing apparatus (1) according to the preceding claim characterized in that in the operational operating mode (E _N ), said value of said first surface temperature is between 130 °C and 170 °C, preferably between 140 °C and 160°C, for example substantially equal to 150°C. Hairdressing apparatus (1) according to any one of the preceding claims characterized in that in the operational operating mode (E _N ), said value of said mass flow rate is between 0.5 g/min and 3 g/min. Hairdressing apparatus (1) according to the preceding claim characterized in that in the operational operating mode (E _N ), said value of said mass flow rate is between 0.5 g/min and 1.1 g/min, for example substantially equal to 0.8 g/min. Hairdressing appliance (1) according to any one of the preceding claims characterized in that before being in said operational operating mode (E _N ), said appliance (1) is designed to be in a transient operating mode (E _T ) during which the value of said first surface temperature of said heating element (4) gradually increases. Hairdressing apparatus (1) according to any one of the preceding claims characterized in that in the operational operating mode (E _N ), the values of said first surface temperature of the heating element (4) and mass flow rate of the steam flow are fixed. Hairdressing apparatus (1) according to any one of the preceding claims characterized in that it comprises a handle (2) for manual gripping as well as a head (3) for engaging the hair which is carried by said handle (2) , said head (3) having a front face (3A) provided with brushing pins (7) between and against which the hair is intended to be, said brushing pins (7) including at least:

• heating pins (70) which contribute to forming said heating element (4), and
• steam pins (71) each integrating a steam ejection orifice (710) connected to a steam source (5, 6), said steam pins (71) contributing to forming said steam emission means.

Hairdressing apparatus (1) according to the preceding claim characterized in that said steam pins (71) come from material with said heating pins (70), said steam pins (71) and heating pins (70) being for example formed by a first one-piece piece (700), for example made of aluminum or cast aluminum. Hairdressing apparatus (1) according to claim 9 or 10 characterized in that each of said heating pins (70) and/or said steam pins (71) has a substantially oblong shape in cross section. Hairdressing appliance (1) according to any one of claims 9 to 11 characterized in that each steam ejection orifice (710) is provided on at least half, and preferably on at least two thirds, of the height of the steam pin (71) which integrates it. Hairdressing apparatus (1) according to any one of claims 9 to 12 characterized in that each steam pin (71) has a substantially flattened shape with two opposite faces, said steam ejection orifice (710) opening onto said two sides. Hairdressing apparatus (1) according to any one of claims 9 to 13 characterized in that said brushing pins (7) also include tensor pins (72) presenting, in said operational mode of operation (E _N ), a second surface temperature whose value is lower than that of said first surface temperature. Hairdressing apparatus (1) according to the preceding claim characterized in that a first plurality (70A) of said heating pins (70) is distributed on the front face (3A) according to at least a first primary row (R1) while a first plurality (72A) of said tensor pins (72) is distributed on the front face (3A) according to at least a first secondary row (R2), said first primary (R1) and secondary (R2) rows being substantially parallel and offset longitudinally for that the pins (70, 72) of said first primary (R1) and secondary (R2) rows are not aligned. Hairdressing apparatus (1) according to claim 14 or 15 characterized in that a second plurality (72B) of said tensor pins (72) as well as a first plurality (71A) of said steam pins (71) are aligned to form a mixed row (R3) within which said tensioning pins (72) and said steam pins (71) are arranged alternately.