RU2785051C2 - Device for measurement of hair properties - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: invention relates to a device for measurement of hair properties, in particular for measurement of a friction force and hair deformation. The device has the first (I) and the second part (II), between which hair (H) pass. The first part (I) contains a measuring probe (MP), and the second part (II) is made with the possibility of deformation of hair (H) on the measuring probe (MP). Both the friction force of hair (H) passing along the measuring probe (MP), and a deformation force (DF) affect the measuring probe (MP). The second part (II) contains a pressing element (PB, S) for pressing hair (H) against the measuring probe (MP) with their compression and contains aligning elements (AE) on opposite sides of the measuring probe (MP) for bending hair (H) in a direction of the measuring probe (MP), and guiding elements (G) for reducing an impact of an angle, at which the device is applied to hair (H), on the friction force and/or the deformation force. At the same time, the measuring probe (MP) is installed on a module (LC-X, LC-Y) of a load sensor for measuring a load.

EFFECT: improvement of a device for measurement of hair properties, provision of a possibility of determination and quantitative assessment of hair characteristics by measuring a combination of surface friction and compressibility of a hair strand.

18 cl, 25 dwg

Description

FIELD OF TECHNOLOGY

[0001] The present invention relates to a device for measuring hair properties.

BACKGROUND OF THE INVENTION

[0002] US 2009/0071228 A1 discloses a method for measuring hair surface smoothness by using a hand-held friction sensor comprising a clamping element and a load cell. A key indicator of the overall condition of the hair is friction. Load cells are well known in the art for measuring friction and can easily be incorporated into a variety of devices. The hair bundle is placed between the gripper and the load cell, and the gripper is closed, which creates a substantially constant normal force in the direction of the hair sample and the load cell. The device is pulled through the hair bundle at a substantially constant speed from the root to the tip of the hair bundle, and the coefficient of friction of the material creates an electrical voltage in the load cell, which is related to the smoothness value of the hair based on the measured coefficient of friction.

[0003] DE 2719482 A1 discloses a specialized hairdresser's comb that contains a strain gauge that can be used to quantify the effectiveness of various types of hair treatments by measuring the hair's resistance to combing before and after treatment. The steel comb contains a strain gauge with a cable and a mounting connector, installed approximately between the teeth and the handle. When the hair is combed, an indication of the deflection of the comb and hence the resistance of the hair to combing is obtained from the strain sensor circuitry.

[0004] FR2442607 A1 discloses a flexible plastic comb that includes a metal plate riveted to it and supporting a sensor containing four strain gauges connected as a measuring bridge. The bridge is powered by a battery connected along one of its diagonals. The cable provides the possibility of placing the battery on the counting circuit, and also provides the possibility of using the output of the bridge to the voltage-frequency converter. The output is applied to a pulse counter with a digital output. The counter value is proportional to the force required to detangle the hair. This arrangement makes it possible to compare the relative characteristics of different shampoos.

[0005] US4167869 A discloses a device for measuring the progressively increasing combing force that a strand of hair is subjected to during combing and providing an instantaneous indication of that force. The device contains a comb or brush with strain gauges attached to it, which change resistance upon mechanical deformation. The change in resistance is electrically measured to provide an indication of gradually increasing combing force. A continuous monitor is connected to the resultant electrical signals to provide instantaneous indication of progressively increasing combing force.

[0006] US2010147323 A1 discloses a hair styling device comprising two arms. Each shoulder has a styling part that interacts with the styling part on the other shoulder for hair styling operation. At least one styling part is configured to heat the hair inserted into the hair styling gap located between the styling parts. A device for measuring pressure is built into one of the two arms. The pressure measuring device detects a pressure or a value representing the pressure applied to the hair between the styling parts when the styling gap is closed. In addition, the hair styling device includes a display device for displaying the pressure or pressure value thus determined.

[0007] EP1958531 A1 discloses an ultrasonic hair fixation device, comprising a main frame, an ultrasonic vibration generating means which is mounted on the main frame and generates ultrasonic vibrations, and a burn prevention means which prevents a human body part other than hair from touching the vibrating surface of the ultrasonic wave generating means. Further, in the embodiment, there is provided a pressing means having a pressing surface which presses the hair against the vibrating surface, a pressure detecting sensor which senses a pressure applied to the vibrating surface, and a control circuit which controls the ultrasonic vibration generating means to generate ultrasonic vibrations only when when the pressure detected by the pressure detection sensor becomes equal to or greater than the set pressure.

DISCLOSURE OF THE INVENTION

[0008] Among other things, it is an object of the present invention to provide an improved device for measuring hair properties. The present invention is defined in independent claims. Preferred embodiments are defined in the dependent claims.

[0009] Embodiments of the present invention provide a device for measuring hair properties. The device has a first part and a second part between which the hair passes. The first part contains the measuring probe, and the second part is made with the possibility of deformation (for example, compression, bending) of the hair on the measuring probe. As the device moves along the hair, the measuring probe is affected by both the frictional force from the hair passing through the measuring probe and the deformation force resulting from the deformation of the hair by the second part on the measuring probe.

[0010] The second part may include a pressing element for pressing the hair against the measuring probe with their compression. Preferably, this compression is the result of pushing the pressing element towards the measuring probe when the hair passes between the pressing element and the measuring probe, while the hair is not compressed before the passage of the hair between the pressing element and the measuring probe. One of the pressing element and the measuring probe may contain a pin, while the other of the pressing element and the measuring probe has an opening for receiving the pin. A spacer may be provided between the first part and the second part to ensure a minimum gap between the measuring probe and the clamping element. The width of the minimum gap can be approximately 0.2 mm.

[0011] In alternative implementations, the second part includes alignment elements on opposite sides of the measurement probe for bending the hair on the measurement probe, and guide elements for reducing the effect of the angle at which the device is applied to the hair on the friction force and/or deformation force, while the measuring probe is mounted on the load cell module to measure the load in two dimensions with the measurement of the friction force and the deformation force, respectively.

[0012] The hair measurement may be built into a hair styler including a treatment plate. In this case, the measuring probe is preferably located along the processing plate, and preferably the length of the measuring probe essentially corresponds to the length of the processing plate.

[0013] In addition, preferably, the measuring device includes a device for compensating the weight of the measuring probe. Preferably, the fixture comprises an accelerometer for measuring the force of attraction in the measurement direction of the measuring probe.

[0014] These and other aspects of the invention will be apparent and explained with reference to the embodiments described below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1A shows an embodiment of a device for measuring hair properties embedded in a hair styling device.

[0016] FIG. 2 shows an embodiment of the first method of implementing the present invention.

[0017] FIG. 3 shows an embodiment of a stand-alone device for measuring hair properties.

[0018] FIG. 4A-4D depict principles of embodiments of the first method for implementing the present invention.

[0019] FIG. 5 shows a second embodiment of a hair property measurement device according to a first embodiment of the present invention.

[0020] FIG. 6 shows a third embodiment of the hair property measurement device according to the first embodiment of the present invention.

[0021] In FIG. 7 shows an embodiment of an embodiment of a second implementation method of the present invention.

[0022] FIG. 8 shows a load cell module for use in the embodiment shown in FIG. 7.

[0023] FIG. 9A-9B depict an embodiment of a stand-alone hair property measurement device according to a second embodiment of the invention.

[0024] FIG. 10A-10D show an embodiment of the measuring device as part of the upper side of the brush.

[0025] FIG. 11A-11C depict another embodiment of a measuring device in accordance with the present invention.

[0026] FIG. 12A-12E show embodiments of a brush having a measuring device on the side where the teeth are.

IMPLEMENTATION OF THE INVENTION

[0027] There is a need in the field of hair care to analyze and evaluate the condition of the hair and/or the health of the hair. Women often assess the condition of their hair by touching and combing their hair with their fingers. In one embodiment, a product is provided in which the "hair feel" principle, i. combinations of the surface roughness of the hair and the ease of deformation of the hair strand, measured in a separate analyzer outside of laboratory conditions, and converted into an indication of the healthy state of the hair.

[0028] The first group of embodiments of the present invention enables the determination and quantification of hair characteristics by measuring the combination of surface friction and compressibility (compression of the hair bundle) of the hair strand with a single sensor. The combination of friction and compressibility is closely related to the way a human finger evaluates hair. The sensor may include a measuring probe (for example, a load cell, for example having the shape of a cylinder) and a mating part that presses the hair strand against the measuring probe with a constant force. By pulling a strand of hair between the measuring probe and the pressure bar, the load cell measures the reaction force. By filtering and processing the measured values, the characteristics of the hair are obtained. The device quantifies "hair feel" by measuring a combination of surface friction and compressibility, while being small enough to fit into a hair styler or other hand-held device, requires no special manipulation to operate, and functions in-line with laying process. The best description of the "feel of the hair" is the combination of the roughness of the surface of the hair and the ease of deformation of the hair bundle (compressibility). For this purpose, the implementation of the measuring device provides the following key features:

• measurement of the combination of friction and deformation of the strand with only two contact elements,

• grasping a strand of hair only through the action of opening and closing,

• measurement of the combination of friction and strain with a single sensor, whereby the ratio of the contribution of friction and strain can be controlled by changing the geometrical aspects of the two contact elements. One of the contact elements is also used for force measurement (for example, by means of a measuring probe).

[0029] In an embodiment, the sensor is integrated into a styling device such as a hair straightener, however, alternatively, the sensor may be included in other open/close devices or a stand-alone device.

[0030] FIG. 1 shows an embodiment of a hair property measurement device incorporated in a hair styling device HS comprising an HP treatment plate. The HP treatment plate may be a conventional heating plate of a hair straightener or a transparent plate in the case where optical radiation is applied to the hair to style the hair. In addition to the processing plate HP, there is a measurement probe MP on the lower part I of the clamp of the hair styling device HS. The arrow in Fig. 1A shows the direction of hair movement.

[0031] In FIG. 2 shows an embodiment of the first method of implementing the present invention. In the embodiment shown in FIG. 2, inside the upper clip part II of the hair styler HS, there is a pressing member formed by the pressure bar PB, which is pushed down by the spring S. Inside the lower clip part I of the hair styler HS, below the measuring probe MP, there is a load sensor LC.

[0032] In the embodiment shown in FIG. 2, the following 4 main components are provided:

• Measuring probe MP: a cylindrical element (but not necessarily cylindrical) of a certain diameter (for example, 5 mm, but not limited to this size), a certain length (for example, 90 mm, but it can be any length that is at least 5 mm) and a certain roughness. The roughness is a very important parameter for the measurement result, however, it is preferably low due to the minimal impact of contamination. The roughness and diameter of the cylinder will affect the ratio of the contribution of surface friction and the deformation force. Preferably, if the measurement probe MP is built into the hair straightener HS, the length of the measurement probe MP is equal to the length of the treatment plate HP to prevent the hair from being squeezed out of the measurement system too easily. Due to the length of the measuring probe MP, a moment is generated on the load cell LC, which measures the force of friction and deformation (for example, compression), resulting in a sensor signal, which depends on the place where the hair strand H comes into contact with the measuring probe MP. This problem can easily be overcome by using a parallel hinge design, which is also seen in load cells used in weighing scales.

• Load cell LC: in an embodiment it can be a standard shear strain cell with a maximum load of 1 N. It is mounted on the measuring probe MP in such a way that the direction of measurement is perpendicular to the direction of attachment. The sensor is not limited to this type of sensor, but can be any type of system for measuring force. For example, a piezo load cell may be used.

• Pressure bar PB: this element causes the hair strand to rub against the probe, providing a measurement of the reaction forces. According to the example, the element has a flat surface, however, the geometry strongly influences the relationship between the contribution of skin friction and the deformation force.

• Pressure spring S: This element presses the pressure bar PB with a certain force against the measuring probe MP when the device is closed. Thus, when a strand of hair is between the pressure bar PB and the measuring probe MP, the hair is compressed with a certain force. According to the example, the spring preload is 0.75 N. A lower force will give a lower signal amplitude. A higher force will give an improved signal, but also more tension on the hair on the head. The force also influences the relationship between the force of friction and deformation.

[0033] FIG. 3 shows an embodiment of a stand-alone device for measuring hair properties. Although in FIG. 3 shows only the measuring probe MP, in the upper half II of the device there is a pressure bar PB pushed down by the spring S, and in the lower half I of the device attached to the measuring probe MP there is a load cell LC as shown in FIG. 2.

[0034] FIG. 4A-4D depict principles of embodiments of the present invention relating to the first group of embodiments. In FIG. 4A shows a strand H of hair from a human head. In FIG. 4B shows that, on one side, the measuring probe MP is placed against the hair strand H. When the hair styling device HS is closed, the pressure bar PB is pressed against the opposite side of the measuring probe MP, with the hair strand H caught between them. The pressure spring S guarantees a constant force. The strand H of hair is pulled through the system by placing the device in a downward direction. As shown in FIG. 4C, two phenomena occur with the counter force RF on the sensor (measurement direction according to the arrow in the image):

• Due to the longitudinal force NF of the pressure bar PB, the net surface friction F of the hair strand H will be measured on the opposite side of the measuring probe MP.

• Due to the compressive effect resulting in deformation force DF, the hair strand H will be pushed towards the bottom of the measuring probe MP, causing a counter force RF. The amplitude of this force depends to a large extent on the ease with which the hair strand H is compressed and hence on the properties of the hair.

[0035] FIG. 4D shows an example of a method for changing the relationship between skin friction and deformation force DF. The hair bending element HB on the clamp bar PB makes the hair strand H become more difficult to be compressed, causing the counter force of the bottom of the measuring probe MP to be increased. However, many different embodiments may be considered.

[0036] An important aspect of hair characteristics is the level of entanglement of the hair strand. This entanglement is difficult to determine based on skin friction and strain separately. In view of this, in the embodiment shown in FIG. 5, a pin EP is installed on the measuring probe MP, and a hole HL is made in the clamping bar PB. By a kind of combing action, it is possible to determine if the strands of hair are tangled. One embodiment is as shown, another embodiment is one in which the pin can be easily installed and removed.

[0037] Although the results provided by the above system are satisfactory, the signal may be clogged by pulling in a few hairs. As long as sufficient hair is present between the measuring probe MP and the pressure bar PB, the contact pressure is relatively low. When there are only a few hairs in the system, and this happens often at the extreme end of the strand, the pressure increases significantly, which leads to deformation of the hair (Hertzian contact pressure), resulting in pinching. An unrealistic value not only clogs the sensor output, but also results in a painful sensation on the user's head. For this purpose, in the embodiment shown in FIG. 6, a spacer is installed between the first part I and the second part II to ensure a guaranteed gap between the measuring probe MP and the pressure bar PB. It is sufficient to ensure a guaranteed gap between the measuring probe MP and the clamping bar PB of approx. 0.2 mm. This size is based on the maximum thickness of the hair. To minimize the risk of hair entrapment, the gap element should be narrow. A possible way to meet both of these requirements is to use a wire with a diameter of 0.2 mm around the pressure bar PB or the measuring probe MP. In another embodiment, narrow elements with a height of approximately 0.2 mm can be attached to the measuring probe MP or the pressure bar PB. In the embodiment shown in FIG. 6, a 0.2 mm thick wire W is provided on the measurement probe MP to provide a gap G of 0.2 mm. In yet another embodiment, the narrow elements can be pressed into the measuring probe MP or the pressure bar PB. The width of the gasket is limited by the fact that the high pressure of the gasket on the opposite element must not exceed the maximum allowable contact pressure.

[0038] The above embodiments of the present invention provide the ability to determine and quantify the characteristics of the hair by measuring the combination of surface friction and compressibility of the hair strand using a single sensor. It is assumed that the sensor is used in an uncontrolled user environment and should be able to measure subtle differences in the forces acting on the hair. The preferred implementation of the present invention is based on the recognition that changing the orientation of the device due to user control of the device can cause a significant error due to the weight of the measuring probe. By measuring the weight contribution in the measurement direction, the influence of the weight of the measuring probe can be compensated. In a preferred embodiment, weight compensation is provided by using a 1-directional accelerometer.

[0039] The hair styling device can be used in all possible orientations. The force of friction and deformation is measured using a measuring probe having a certain weight. In an embodiment, this weight is added to the friction signal depending on the orientation of the styler and based on the direction of the attractive force vector. Since the weight of the measuring probe can be significant in the signal, the weight contribution is preferably removed from the force sensor readings. The main point of this embodiment is to know the instantaneous contribution of the weight of the measuring probe to the strain force sensor signal. For this purpose, the implementation uses:

• A 1-directional absolute accelerometer located in the direction along the direction of measurement (or another 1-directional sensor that determines the contribution of the attractive force to the direction of measurement of the strain force sensor), and

• Known weight of the measuring probe.

[0040] The resulting output is not affected by the weight:

Friction and deformation force [N]

= Sensor output [N] - (Accelerometer output [m/s ² ] * Weight [g])

[0041] In an embodiment, compensation includes:

• Measurement of the attraction force sensor in the same direction as the direction of the deformation force sensor. In the example, this is done using a standard accelerometer, such as accelerometers that are used in smartphones. Another embodiment may be a second force sensor with a certain mass, located in the same direction as the deformation force sensor with a measuring probe. The second force sensor is configured to measure the contribution of the attractive force to the measurement signal. In practice, in order to meet the measurement requirement in the same direction of both systems, the strain force sensor and the accelerometer are mounted on the same structure in the measuring device.

• Information about the weight of the measuring probe.

• Most likely (but not necessarily) a microcontroller that subtracts accelerometer compensation data from the strain force sensor signal to produce a "real" force signal. Another embodiment could be an analog subtraction circuit, where an analog sensor is used to obtain the attractive force contribution. It is even possible to completely omit the circuit when the same sensor is used for force detection and attraction force detection with a mass attached to the attraction force sensor equal to the mass of the measuring probe. In this case, the signals can be directly subtracted from each other, giving a compensated strength signal.

[0042] If, due to device manipulation performed by the user, the orientation of the strain force sensor has an angle ϕ to the z-axis of the world coordinate system, where the z-axis is in the negative direction of the earth's gravity force, the output of the force sensor during operation will be:

Force sensor output

= Friction force + Weight * gcos(ϕ)

[0043] Since the orientation of the accelerometer is mechanically coupled to the orientation of the strain force sensor, the output of the accelerometer will simultaneously be:

Accelerometer output = gcos(ϕ)

[0044] Together with the known weight of the measurement probe, the microcontroller can calculate compensation by multiplying the output of the accelerometer by its known weight:

Calculated Compensation

= Weight * Accelerometer output

= Weight * gcos(ϕ)

[0045] If, when measuring the strain force, compensation is added to the signal, the measuring system determines only the required friction force:

System output

= strain force sensor output - Computed compensation

= Friction Force + Weight * gcos(ϕ) - (Weight * gcos(ϕ))

= Force of friction

[0046] In order to ensure that the contribution of acceleration due to movements is low compared to the force of attraction, the weight of the measuring probe is preferably as small as possible.

[0047] In a second embodiment of the present invention, there is provided a hair health analyzer capable of detecting and quantifying hair characteristics by determining the relative coefficient of friction using two sensors, which can also be implemented as load sensors. The basic principle for the second embodiment of the present invention is to use the bending stiffness of the hair to apply a deformation force generated by a normal force to the surface to measure the dynamic friction coefficient of the hair strand and along the length of the hair strand. One sensor (load sensor LC-Y in the Y direction) measures the surface friction force between the hair and the measuring probe, and the other sensor (load sensor LC-X in the X direction) measures the dynamic bending stiffness of the hair strand (which is the th force applied to the surface of the measuring probe). The combination of sensors is integrated into the hair analysis device or the hair styling device, for example as shown in FIG. 1. Using a hair health analyzer, a strand of hair is clamped between two pins and a measuring probe, and the hair health analyzer is pulled from the tip to the root. The relative coefficient of friction can be calculated by the hair health algorithm using the output from the two sensors.

[0048] In an embodiment of the device, the "hair feel" is quantified by determining the coefficient of friction using the output from a combination of two sensors. Simultaneously, the sensors measure two forces, the force associated with the movement of the two surfaces relative to each other, and the force perpendicular to the pull axis, hence friction and normal force, respectively. The normal force is generated by forcibly bending the hair through the measuring probe. Small enough to fit into a standalone analyzer, the output from both sensors is used to determine the coefficient of friction over time, limiting the need for special manipulations for operation and can also be easily used by the user outside of a controlled laboratory environment.

[0049] In an embodiment, a measurement device is provided, wherein the friction force and the deformation force (here: bending force) of the hair are determined using the following key features:

• Use a 3-point bending stiffness test scheme to:

Измерения деформации пряди путем измерения силы деформации (здесь: силы сгибания), перпендикулярной направлению протягивания пряди. Прикладывание нормальной силы к поверхности датчика для определения трения с использованием силы сгибания волос.

Strand deformation measurement by measuring the strain force (here: bending force) perpendicular to the direction of the strand pull. Applying a normal force to the sensor surface to determine friction using hair bending force.

• Capturing the strand only through the action of opening and closing.

• Simultaneous measurement of dynamic bending force (X direction) and friction force (Y direction) along the length of the hair strand using two sensors, while the relationship between friction and bending force can be optimized by changing the geometric aspects of the three elements of the test system, namely the two supports and one measuring probe (see Fig. 7 for the configuration of the measuring device). Using both sensors, the coefficient of dynamic friction along the hair strand can be determined.

[0050] The embodiment shown in FIG. 7 contains four key components:

1. Measuring probe MP: Cylindrical element (but not necessarily cylindrical) of a certain diameter (here 6 mm, but not limited to this size), a certain length (here 12 mm, but it can be any length) and with a certain roughness (here Ra ~ 0.3, however it can have any surface roughness). The friction between two surfaces depends on the surface roughness and the contact surface area. Roughness and contact surface area are expected to influence the coefficient of friction ratio due to an increase or decrease in skin friction.

2. Load Cell Module (See Fig. 8 for more details): In this case, standard shear strain gauges with a maximum load of 1 N (Y direction) and 7.8 N (X direction). They are installed in such a configuration that both sensors measure in the desired direction without affecting each other. The sensors are not limited to this type of sensor, but can be any type of system for measuring force. The load cell module comprises a first load cell LC-Y in the Y direction connected to the measurement probe MP, a connecting piece CP and a second load cell LC-X in the X direction. The second load cell LC-X has a surface RW that interacts with the environment.

3. Alignment elements AE formed by supports (for example, support pins) are located adjacent (at distances SS between supports, for example, 6.35 mm in an embodiment in which the radius of the measuring probe is 2.7 mm) with the measuring probe MP with constant overlap, length, diameter and materials, in this case with overlap or deviation D of 4 mm, length of 20 mm, diameter of 4 mm and stainless steel as material, however they can be of any size , length, diameter and material. The overlap D determines the contribution of the force in the X direction (normal force) to the coefficient of friction, which depends on the volume of the hair strand and the individual stiffness of the hair when bent. Leveling elements AE may be fixed, however, they may be dynamic through the use of rollers to reduce drag or include a speed sensor. Alignment members AE are used to bend the hair H and use the bending stiffness of the hair to apply a normal force to the measurement probe MP. The radius of curvature can be adjusted by moving the alignment elements (support pins) AE in the direction of the measuring probe MP (deflection) or moving it in the X direction (distance SS between the supports). Differences in the X and Y direction will increase or decrease the normal force on the system.

4. Guide elements G formed by elements to help remove pulling forces in the system caused by a retained angle. These elements have a specific diameter and material (here 4 mm and stainless steel), but they can be of any diameter and material. The guides G may be fixed, however, they may be dynamic by using rollers to reduce drag or include a speed sensor.

[0051] In the embodiment shown in FIG. 7, the left guide members G, the measuring probe MP, and the load cell module belong to the same device part I, while the right guide members G and the alignment members AE belong to the other device part II, between which the hair H passes. The alignment members AE and the guide members G absorb the pull forces needed to remove additional forces from the transducer system, providing a clean measurement of friction in the Y direction that is independent of speed. The tip (far) parts of the hair can move freely in all directions, and the upper (near) part of the hair is attached to the scalp.

[0052] Alignment elements AE and guide elements G provide another advantage. With a device held in the hand, it is difficult to use the same angle, speed and volume of a strand of hair during measurements or in one measurement. One factor is the angle of the incoming hair strand relative to the device, which will change as the device is used by the end user. The arrangement of the guide pins G and the support pins AE ensures an equal configuration between the hair strand H and the measuring probe MP for every measurement. By default, the selected design provides a constant angle in the hair friction area. In particular, the guiding elements G will cause the hair to enter the area of interest at the same angle, regardless of the angle at which the user applies the device to the hair H. By this configuration, the curvature of the hair is standardized regardless of the angle used by the user.

[0053] FIG. 9A-9B show an embodiment of a stand-alone device for measuring hair properties according to the second embodiment of the invention, in which the measuring probe MP and half of the guide members G are in the body part I, in which the load sensor module is also located, and the alignment members AE and the other half of the guide elements G are located in the covering part II of the measuring device. Preferably, the guide elements G are oriented so that the hair will fall flat and straight in the direction of the measurement unit (supports and measurement probe MP) and for this purpose they may have hinged surfaces.

[0054] In an embodiment, the measurement is performed as follows:

1. The system is initially opened or closed before the hair strand H is introduced into the system, and it may be opened or closed, for example by pressing a button or other suitable method.

2. A strand H of hair is introduced into the system between the measuring probe MP and the leveling elements (eg support bars) AE.

3. The system is closed to clamp the hair strand H between the leveling elements (support strips) AE and the measuring probe MP. The guide elements G have a small gap between them, for example 2 mm (however, the gap can be any size), determining the pull force of the analyzer applied by the user and the amount of hair in the system.

4. The analyzer is pulled down to the tip of the hair strand H. During the downward movement, the friction between the surface of the measuring probe MP and the hair strand H will be determined, and the normal force over time or along the length of the hair strand will be calculated at the same time. This depends on the bending stiffness of the hair strand H between the alignment elements AE and the measuring probe MP.

5. Receive data from both sensors and then determine the coefficient of friction over time using the following equation:

[0055] Here, the various terms have the following meanings:

Symbol Definition Coefficient of friction of the whole strand of hair Measured friction force Measured normal force (deformation force) n Number of recorded data samples

The coefficient of friction is used as a parameter to determine the "feel of the hair" of the user.

[0056] Preferably, the coefficient of friction thus calculated, based on both the friction force and the strain measured by the respective load sensors LC-X and LC-Y, is not affected by volume changes that may result from, for example, damaged hair, or H hair that has been cut to different lengths so that the volume of the hair strand is not constant along the length of the hair strand. If only the normal or frictional force was measured, the result would be that the system is strongly influenced by the amount of hair the user has placed in the system.

In FIG. 10A-10D show a brush with a sensor module located in the back. The hair is inserted manually into the slot in which the measuring probe is located. Thus, the measuring device may be part of the upper side of the brush B, the teeth Bt of which are mounted on the lower side. In FIG. 10A shows the top of brush B, FIG. 10B is a cross section along a horizontal line in the middle of FIG. 10A, in FIG. 10C is a cross section along the vertical line in FIG. 10A through reference symbol II, and in FIG. 10D shows some sketches of the MP measuring probe and the guide and holding part of the GHP for use in this brush B.

[0057] As shown in FIG. 10A and 10B, a notch S is provided on the upper side of the brush B, in which hair can pass through. The second part II of the measuring device shown in FIG. 10A-10D is stationary, while in the embodiment shown in FIG. 9A-9B she was articulated. The upper part of the second part II of the measuring device is at the same level as the upper part of the brush B, while the first part I of the measuring device is in the cavity in the upper part of the brush B. FIG. 10C is a cross-sectional view with the same elements as previously described: measuring probe MP and alignment elements AE. In order to allow the hair to easily enter the measuring device, it is possible that the measuring probe MP moves down when the hair tuft enters, after which it moves up to ensure that the second part II deforms the hair H on the measuring probe MP as the hair H passes between the first part I and the second part II. In the embodiment shown as a sketch in FIG. 10D, the guide and holding part GHP, located in front of the measurement probe MP in the direction of hair entry, is in the down position when hair enters (shown in the upper half of FIG. 10D), and in the up position, preventing hair from escaping from the side (i.e. direction perpendicular to the hair H) as the hair passes between the first part I and the second part II, as shown in the lower half of FIG. 10D.

[0058] FIG. 11A-11C depict another embodiment of a measuring device in accordance with the present invention. In FIG. 11A is a front view, and FIG. 11B is a cross-section along line A-A in FIG. 11A. In FIG. 11C shows three possible variants of the measuring probe MP and alignment elements AE as alternatives to the circled part in FIG. 11B. The measuring device shown in Fig. 11A-11C has a base Bs, on the top of which there are three teeth, which form two alignment members AE and a measuring probe MP, respectively. The MP probe contains a probe module SM, on top of which is a probe prong ST. The sensor module SM may be located inside the base Bs. The teeth AE, ST can be fully rigid or flexible above the fold line BL to prevent excessive hair pull when the hair is tangled. As in the embodiment shown in FIG. 10A-10D, in the embodiment shown in FIG. 11A-11C, movable parts I and II are not provided.

[0059] As shown in FIG. 11C, the alignment elements AE and/or the sensor prong ST preferably have angled tips above the fold line BL to facilitate entry of the hair into the measuring device. To ensure that as the device is moved through the hair, it does not leave the device at the top (i.e. in the direction perpendicular to the hair H), the aligning elements AE and/or the prong ST of the sensor can be equipped with a hair blocking element (not shown) located approximately on the fold line BL, while the hair blocking element is controlled manually or automatically. In addition, this hair blocking element can serve to block further entry of hair once a certain amount of hair has entered the detection area. This hair blocking element can be activated, for example, as soon as the force sensor is above a certain threshold, and deactivated if the sensor output appears to be stable.

[0060] FIG. 12A-12E show embodiments of a brush B having a measuring device on the side where the teeth Bt are. The device contains the same elements as described in the previous implementations: measuring probe MP, leveling elements AE and guiding elements G. As in FIG. 10A-10D and 11A-11C, the first part I and the second part II are fixed relative to each other; different elements may be assigned to the first part I and the second part II, as in the embodiment shown in FIG. 7.

[0061] The embodiment shown in FIG. 12A is based on the measurement device shown in FIG. 7. In such a case, the basic version is that when combing the hair, the hair H is guided along the alignment elements AE and the measuring probe MP. By dragging the brush through the hair, a friction force is generated in load cell Y (LC-Y) and a bending force is generated in load cell X (LC-X).

[0062] The embodiments depicted in FIG. 12B-12E aim to increase the amount of hair that is captured in the system in order to obtain an enhanced measurement signal.

[0063] The embodiment shown in FIG. 12B is an improved version of the embodiment shown in FIG. 12A. The upper parts of the leveling element AE and the measurement probe MP are bent in such a way that when combing the hair, most of the hair is caught in the opening of the measuring system, giving an amplified measurement signal. An additional G guide pin has been added to reduce dependency on the device's held angle.

[0064] In the embodiment shown in FIG. 12C, the entire measuring probe MP is at a low angle. Due to the small angle, the hair is caught and held in the system, since only small forces are required for this. As a consequence, the bending force is no longer constant along the length of the measuring system. Since the parameter used is the coefficient of friction, tests have shown that asymmetry does not affect the system.

[0065] In the embodiment shown in FIG. 12D, not only the measuring probe MP but also the alignment members AE are angled. Thus, even more hair is retained in the system, giving an enhanced measurement signal.

[0066] The embodiment shown in FIG. 12E aims to solve the problem that when the brush is not perpendicular to the direction of the hair on the head, but at some angle, the hair is guided to the wrong side of the measurement probe MP, giving a false measurement signal. In order to prevent hair from being on the wrong side of the measuring probe MP, both alignment members AE and both guide members G are interconnected. In this case, the hair will only face the required side of the MP measuring probe.

[0067] It should be noted that the above embodiments illustrate and do not limit the present invention, and a person skilled in the art will be able to implement a wide range of alternative implementations without departing from the scope of the appended claims. In the embodiment shown in FIG. 7, the dimensions of the measuring probe, the radius, the deflection D, and the distance SS between the supports can be sized according to the surface area of the measuring probe that is in contact with the hair H. devices. The guiding of the hair can be done in one piece containing two guides, but it can also be done with two separate guides. In addition, the gasket can be located in another area of the structure in case of its execution with a hinge. In the claims, no parenthesized reference is to be considered as a limitation of the claim. The word "comprising" does not exclude the presence of elements or steps other than those specified in a claim. The grammatical indicator of the singular before an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by hardware comprising several different elements and/or by a suitably programmed processor for analyzing the signal from the measurement probe MP. In a device claim that lists multiple features, multiple of those features may be implemented by the same piece of hardware. The mere fact that certain measures are listed in mutually distinct dependent clauses does not in itself indicate that a combination of these measures cannot be used successfully.

Claims (18)

1. A device for measuring the force of friction and deformation of the hair (H), containing: the first part (I) containing the measuring probe (MP), and characterized in that the device contains the second part (II) for bending the hair (H) on the measuring probe (MP) when the hair (H) passes between the first part (I) and the second part (II) along the measuring probe (MP), the device contains leveling elements (AE) and guiding elements (G), wherein the leveling elements (AE) are connected to each other with each other, and the guide elements (G) are connected to each other. 2. The device of claim 1, wherein the measurement probe is subjected to both a frictional force from hair passing over the measurement probe and a deformation force resulting from the bending of the hair by the second part on the measurement probe as the device is moved through the hair. 3. The device according to claim 2, configured to subject the measuring probe (MP) to both the frictional force from the hair (H) passing through the measuring probe (MP) and the deformation force (DF) resulting from the bending of the hair (H) the second part (II) on the measuring probe (MP). 4. The device according to any one of paragraphs. 1-3, in which the second part (II) contains a pressing element (PB, S) for pressing the hair (H) against the measuring probe (MP), while the device is configured to press the hair (H) by pushing the pressing element (PB, S) in the direction of the measuring probe (MP) when the hair (H) passes between the pressure element (PB, S) and the measurement probe (MP), the device being designed in such a way that the hair (H) is not compressed before it passes between the pressure element ( PB, S) and measuring probe (MP). 5. The device according to claim. 4, in which one of the pressure element (PB, S) and the measurement probe (MP) contains a pin (EP), while in the other of the pressure element (PB, S) and the measurement probe (MP) is made hole (HL) to receive the pin (EP). 6. Device according to any one of the preceding claims, wherein a spacer (W) is installed between the first part (I) and the second part (II) to ensure a minimum gap between the measuring probe (MP) and the pressure element (PB, S). 7. Apparatus according to claim 6, wherein the width of the minimum gap (G) is approximately 0.2 mm. 8. The device according to claim 3, in which the alignment elements (AE) are installed on opposite sides of the measuring probe (MP) in a plane parallel to the boundary between the first part (I) and the second part (II), for bending the hair (H) on the measuring probe (MP). 9. The device according to paragraphs. 1, 2, 3 or 8, in which the measuring probe (MP) is installed on the module (LC-X, LC-Y) of the load cell to measure the load in two dimensions with the measurement of friction force and deformation force, respectively. 10. Apparatus according to any one of the preceding claims, further comprising a device for compensating the weight of the measuring probe (MP). 11. An apparatus according to any one of the preceding claims, further comprising an accelerometer for measuring an attractive force in the measurement direction of the measuring probe (MP). 12. An apparatus according to any one of the preceding claims, wherein the measuring probe (MP) is at least partially flexible or inclined. 13. Device according to any of the preceding claims, wherein the element of the second part (II) is at least partially flexible or inclined. 14. Device according to any of the preceding claims, built into a brush (B) having a plurality of teeth (Bt). 15. A device according to any one of the preceding claims, wherein the measuring probe (MP) is movable to allow hair (H) to enter the device. 16. A device according to any one of the preceding claims, further comprising a part (GHP) for preventing the hair (H) from exiting the device in a direction perpendicular to the hair (H). 17. The device according to any one of paragraphs. 1-13 built into a hair styling device (HS) comprising a treatment plate (HP) with a measuring probe (MP) located along the treatment plate (HP). 18. The apparatus of claim. 17, wherein the length of the measuring probe (MP) essentially corresponds to the length of the processing plate (HP).

Images