WO2025172593A1

WO2025172593A1 - Device for heating a container and device for collecting hair fibers

Info

Publication number: WO2025172593A1
Application number: PCT/EP2025/054126
Authority: WO
Inventors: Thibaut Quelquejay; Assya ASSAOUI; Philippe ANGEVIN; Yann Waye Keuong; Lucien BILDSTEIN; Nicolas Daubresse; Joanna GOMES
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2024-02-16
Filing date: 2025-02-14
Publication date: 2025-08-21
Anticipated expiration: 2026-08-16

Abstract

An assembly made up of a container and a device for heating the container, the heating device comprising: - a housing; - a heating element contained in the housing and defining a cavity for receiving the container, intended to heat the container by dry conduction.

Description

Title: Device for heating a container and device for collecting hair fibers

Technical field

The present invention relates to a device, and more generally an assembly, for allowing the controlled heating of a container. The present invention particularly relates to a device for heating a test sample, for example a biological material placed in solution.

According to another aspect thereof, the present invention also relates to a device for collecting hair fibers, and a method for collecting such fibers.

Prior art

Numerous heating devices are known that are intended to heat a container and are able to operate by conduction or convection. These include, inter alia, bottle warmers, wax heaters, thermostatic baths, electric flask heaters, and heating plates. These different devices are used in an extremely wide range of contexts and conditions of use. In particular, laboratory equipment, such as thermostatic baths, electric flask heaters, or laboratory heating plates, must be handled with care. Such equipment also has a considerable cost. Common items of equipment such as wax heaters and bottle warmers are very limited in their use, and the temperatures reached are relatively imprecise.

If a user wishes to perform tests involving chemical reactions, imprecision with respect to the temperature may lead to variability of the results that is detrimental to the interpretation thereof and to the reliability of the test.

In addition, devices operating on the principle of a water bath lead to a greater risk of scalding in the event that they are knocked over by accident, due to the splashing of the liquid forming the bath.

Furthermore, hairdressers commonly collect hair fibers from a client’s hair in order to test that the effect of a product that they wish to apply to the client’s hair matches the desired effect.

Various devices for collecting hair fibers exist that comprise collars with a collecting groove, collars with a spiked surface or an adherent material, and suction devices. Moreover, in some cases, the hair fibers collected are sent to a third party, typically in an envelope, loose or tied together, for example using adhesive tape or a clip.

Collecting methods have also been developed in order to avoid direct contact between the fingers of the operator performing the collection and the hair fibers collected, when the collection is being performed as part of a forensic investigation. These methods typically use adherent materials, combs, optionally comprising a stem that makes it possible to select and isolate a row of fibers. The fibers thus collected are generally tied together before being placed in a container such as an envelope.

Disclosure of the invention

Heating device

There is a need for a heating device that makes it possible to heat a container in a controlled manner, that is compact, light and accessible to the general public, and that is safe to use.

There is also a need for an improved heating device making it possible to reach a given temperature quickly.

There is a further need for a device that makes it possible to maintain a given temperature without exceeding it.

According to a first aspect thereof, the invention aims to meet all or some of these needs.

Collecting device

In addition, there is a need to have a tool that is easy to produce and use, making it possible not only to select a desired quantity of hair fibers and collect the hair fibers selected, but also to introduce them into a relatively small container, such as a vial or pill bottle, making it possible to transport and/or apply a treatment to said hair fibers, preferably while avoiding direct contact between the operator performing the collection and the hair fibers collected. Moreover, there is a need to make it possible to collect a predetermined quantity of fibers simultaneously, and to introduce these fibers into a device or a vial, in a short handling period and without the use of a step of tying the fibers together.

There is also a benefit in having a device and a method that make it possible to minimize the number of hair fibers to be collected.

According to a second aspect thereof, the invention aims to meet all or some of these needs.

Summary of the invention

Heating device

According to a first aspect, the invention relates to an assembly formed by a container and a device for heating the container, the heating device comprising:

- a housing;

- a heating element contained in the housing and defining a cavity for receiving the container, intended to heat the container by dry conduction.

The assembly according to the invention advantageously makes it possible to limit the risk of scalds, due to the absence of liquid at the interface between the container and the heating element. In the event that the device is accidentally knocked over, if the container is closed, there is thus no risk of splashing, unless the container breaks.

The device according to the invention may make it possible to control the temperature to which the container is heated quickly and precisely, using a lower control limit.

Such a device may also make it possible to reach a given temperature in a shorter time.

Generally, unlike bottle warmers, wax heaters, or water baths, conduction by dry contact, in other words without a heating fluid, and with low inertia, makes the temperature increase much faster. The invention further provides an assembly for heating a container that is compact, light and safe for the user.

The cavity may have a shape that complements the outer shape of said container. This makes it possible to maximize the heat exchange surface between the container and the heating element. Preferably, more than 80% of the container is inserted into the cavity, and, better still, more than 90% of the container is inserted into the cavity. This makes it easier to hold the container in the device, and to cover the container with a lid that makes it possible to reduce the risk of breakage of the container in the event that the device is accidentally knocked over. It also makes it possible to have a large heat exchange surface and a more uniform temperature of the wall of the container.

Such an assembly particularly makes it possible to obtain a compact assembly while maximizing the heat exchanges and thus improving thermal performance.

The container may in particular be a tubular container having an outer diameter greater than or equal to 2 cm and less than or equal to 3 cm.

The assembly is particularly suitable for performing tests on samples, quickly and easily, without using laboratory equipment.

The heating element may comprise a heating sleeve made up of a ceramic-coated heating resistor.

Generally, the resistor is preferably coated with a material having low mass and low thermal inertia.

The heating sleeve may be a split collar.

The heating element may comprise a collar for clamping the heating sleeve, the clamping collar adjusting the inner diameter of the heating sleeve so that the container fits into the cavity of the heating element with sufficiently little clearance to allow the heating of the container by dry conduction. The heat losses thereof are advantageously limited. The collar may be adjusted by tightening a screw, a temperature sensor such as a thermistor being positioned in direct contact with said screw. Such an arrangement makes it possible to have a good image of the temperature of the collar by means of the temperature sensor.

In some particular embodiments, the assembly comprises a temperature controller configured to heat the container to a predefined temperature, and optionally maintain this predefined temperature for a predetermined time period, the temperature being in the range [70°C ; 110°C], better still in the range [90°C ; 100°C], and, preferably, this temperature is maintained for a time period greater than or equal to 3 minutes and/or less than or equal to 10 minutes. This temperature control may make it possible to limit the risks of burns and scalds by not exceeding certain temperatures. This control may also make it possible not to exceed temperatures that could damage the contents of the container by heating to an excessively high temperature.

The temperature controller may be a PID (proportional - integral - derivative) controller. In particular, the PID controller may have a proportional gain Kp of between 0.2 and 0.4 and a proportional gain Ki of between 0.05 and 0.15.

The housing may comprise a base having an opening through which the container is intended to be introduced into the base, and a lid hinged on the base between an open position and a closed position.

In particular, the lid may be pivotably mounted about an axis of rotation substantially parallel to an axis of insertion of the container into the base and into the cavity of the heating element.

In the closed position, the lid retains the container in the housing, and limits or even prevents access to hot surfaces of the device or of the container.

In addition, the heating device may comprise a contact switch arranged so that the closed position of the switch is triggered by rotating the lid, when the lid pivots into the closed position, the switch being configured so as to prevent heating when the switch is open.

The heating of the container may thus be dependent on the closing of the lid, improving user safety. This also makes it possible to limit energy consumption, by stopping heating as soon as the lid is opened. This may also limit the number of operations, if appropriate, by avoiding having to actuate a button to stop heating.

In some embodiments of the invention, the lid is fastened to a rod positioned inside the housing and comprising a stop element intended to come into contact with the switch when the lid is in the closed position, the switch being in the closed position when it is in contact with the stop element.

The assembly may further comprise a thermally insulating stopper of the container. The heat losses thereof are advantageously limited, and the handling of the container is facilitated.

The lid may comprise a lateral opening, so that it may be engaged on a container that is not fully inserted into the cavity. This makes it simple to retain access to the stopper of the container in order to remove it from the device, once the lid is in the open position. The heating element may be arranged in a support that thermally insulates the heating element from the housing, the support being fastened to an upper portion of the housing, and in particular, when the housing comprises a base and a lid, the support being fastened to an upper portion of the base.

In order to ensure the electrical safety of the heating device, a fuse and a ground wire may be positioned in a lower portion of the support. In particular, the fuse may be a thermal cutoff or a resettable safety thermostat, also known as a resettable Klixon.

The bottom of the support may comprise a slot having the general shape of an angular sector (that is, a segment), the vertex of the angular sector being situated substantially in the center of the bottom of the support. Preferably, the slot comprises a widening at the vertex of the angular sector, the opening angle of the angular sector being greater than or equal to 15° and less than or equal to 45°.

Collecting device

According to a second aspect, the invention relates to a hair fiber collecting wand, comprising a stem that extends along a longitudinal axis and comprises in a distal portion a slot extending substantially longitudinally so as to form at least one first prong and at least one second prong, the length of the first prong being less than the length of the second prong.

The first and second prongs, separated by the slot, make it possible in particular to select and hold the hair fibers with a view to collecting them. More specifically, the longer second prong makes it possible to select the hair fibers to be collected. Once the hair fibers have been selected in the desired quantity, the operator may slide these hair fibers into the slot so as to trap them between the first and second prongs of the wand. They may then wind the hair fibers around the first and second prongs before finally cutting off the hair fibers.

The wand may have a length greater than 10 cm, and/or less than 20 cm, and preferably the length of the wand is between 13 cm and 17 cm, in particular substantially equal to 15 cm.

“Wand” is given to mean an elongate, slender tool. In particular, the largest transverse dimension of the wand does not exceed l/5th of its length. In particular, the wand does not comprise a large loop at its proximal end, unlike a twist-key can opener.

The length of the wand corresponds to the maximum length thereof along the longitudinal axis X. Such a length offers good maneuverability. In particular, it allows the operator to handle the wand accurately with just one hand.

The length of the first prong may be less than or equal to 3/4 of the length of the second prong, better still less than or equal to half of the length of the second prong, even more preferably less than or equal to one quarter of the length of the second prong.

The difference in length between the first prong and the second prong may be less than or equal to 2.5 cm, better still less than or equal to 2 cm, even better still less than or equal to 1.5 cm.

The length of the first prong may be less than or equal to 2 cm, preferably less than or equal to 1 cm, and/or greater than or equal to 5 mm.

The length of the second prong may be greater than or equal to 8 mm, preferably greater than or equal to 1 cm, and/or less than or equal to 8 cm, preferably less than or equal to 4 cm.

These dimensions are particularly well suited to collecting hair fibers.

The stem may have a substantially cylindrical shape, excluding the slot. The envelope surface containing the two prongs may have an overall shape that is substantially cylindrical, or conical, optionally truncated.

The stem may have a rounded transverse cross section, for example a circular or elliptical transverse cross section.

The stem may have a constant transverse cross section, in particular along more than half of its length. Alternatively, the stem has a transverse cross section of variable dimensions.

Preferably, the transverse cross section of the stem has a larger dimension of between 3 mm and 10 mm, preferably between 4 mm and 8 mm, for example substantially equal to 5 mm.

In one embodiment, the slot extends to a distance greater than or equal to 1 mm and/or less than or equal to 5 mm, or even less than or equal to 2.5 mm, from the outer surface of the stem.

The slot may extend over a depth of between 5 mm and 2 cm. The depth is measured parallel to the longitudinal axis of the wand when the slot is parallel thereto.

The slot may have a width greater than or equal to 1 mm, preferably greater than or equal to 1.5 mm. The slot may have a width less than or equal to 2 mm, preferably less than or equal to 1.5 mm.

The distal portion of the stem may be beveled and/or truncated.

Preferably, the beveled distal portion is of conical envelope.

The beveled distal portion may be truncated.

The beveled distal portion may extend over at least 5% of the length of the wand, better still at least 10% of the length of the wand, even better still at least 15% of the length of the wand.

Such a wand with a tapered end in particular allows finer, easier selection of the hair fibers from the hair.

The wand may further comprise a gauge extending transversely to the longitudinal axis X.

The gauge advantageously makes it possible to more precisely estimate the quantity of hair fibers that will be collected, and thus allows calibrated, fast, precise collecting of the fibers. In particular, the collecting of hair fibers from the hair by a hairdresser is often perceived as unpleasant by clients. This is why it is essential to only take a limited and necessary number of hair fibers.

The gauge may be a hole, an annular groove, or a recess intended to receive hair fibers. In particular, the gauge may form a V flush with the surface of the stem.

The gauge preferably has a maximum depth of between 0.7 mm and 1 mm, and in particular the maximum depth may be approximately 0.9 mm.

The maximum width of the gauge may be between 0.8 mm and 1.2 mm, and in particular the maximum width may be approximately 1 mm.

These dimensions are particularly suitable for obtaining a sufficient quantity of hair fibers to perform a test on a sample of hair fibers, in particular with the aim of checking the reaction of a dye or bleach on the hair fibers.

The gauge may be formed in a proximal or median portion of the stem.

The gauge may be formed near the bottom of the slot, in other words near the join between the first prong and the second prong, particularly at a distance from the bottom of the slot less than or equal to 10 mm, 8 mm, or 5 mm.

Having selected hair fibers to collect and before winding the hair fibers around the first and second prongs, the operator may thus measure the quantity of hair fibers selected by engaging it in the gauge and checking whether or not this quantity corresponds to the desired quantity to be collected.

The operator may for example check visually whether the selected quantity of hair fibers overflows from the gauge or whether it does not completely fill the gauge. The operator may then adjust the quantity of hair fibers before proceeding to perform the actual collection.

The presence of a gauge is particularly advantageous as it makes it possible to efficiently collect the optimum quantity of hair fibers.

The wand may comprise a retaining element intended to retain the hair fibers to be collected on the stem.

Such a retaining element advantageously makes it possible to transport the hair fibers collected to a container without loss, while avoiding, if appropriate, any direct contact between the operator and the hair fibers collected.

The retaining element may be positioned on the stem so as to retain the hair fibers after the operator has wound the fibers around the first and second prongs and before the operator cuts off said hair fibers.

The retaining element may take the form of a ring, sliding along the stem, with slight friction if appropriate.

In particular, the retaining element may have an insertion cone diverging toward the distal end of the wand and arranged to cover the wound hair fibers during the collection of hair fibers.

The retaining element may be elastically deformable.

The stem may comprise at least one protrusion providing, due to the friction that it generates, an immobilized position of the retaining element around the stem.

The stem may comprise at least two end stops of the retaining element, the retaining element sliding between these two stops.

Alternatively, the retaining element may be removable.

The retaining element may comprise, on the surface thereof facing the stem, a flat area in order to limit its rotational movements around the stem, the stem in this case having a non-circular outer profile adapted to the shape of the retaining element. It may also be advantageous to be able to push the hair fibers collected down into a container intended to receive them, and/or to be able to extract them from this container.

To this end, the wand according to the invention may comprise a widened proximal portion, for example having a larger diameter than a median portion of the stem.

The widened portion may be formed by molding or cutting, or be an attached endpiece.

The widened portion may have a larger transverse dimension, in particular a diameter, of between 8 mm and 12 mm, preferably approximately 10 mm, and/or a length of between 5 mm and 20 mm, preferably between 7 mm and 10 mm, for example approximately 8 mm.

The widened portion may be arranged so as to make it possible to push the hair fibers collected down into a particular container, and preferably has a circular end profile, being for example substantially in the shape of a right circular cylinder.

The wand may comprise a hook at the proximal end of the wand.

This hook may be formed in the aforementioned widened portion, if appropriate.

The hook may have a width of between 2 mm and 9 mm, better still between 4 mm and 6 mm.

The wand may be at least partially covered with a coating, so as to provide a smooth surface and/or a slightly rough surface and/or an adherent surface.

Such a coating facilitates the adhesion of the hair fibers to the stem, particularly to the prongs.

The first prong and/or the second prong may be at least partially provided with spikes on their surface, the spikes extending radially, the spikes preferably being flexible.

At least one portion of the wand, preferably the first and/or second prong, may be a pale color, in particular a beige, pastel or white tone.

Alternatively or additionally, at least one portion of the wand, preferably the first and/or second prong, may be a dark color, in particular a gray or black tone.

Such colors make it possible to optimize the contrasts with the color of the hair and more clearly distinguish the hair fibers to be collected.

The wand may in particular be at least partially made from injected plastic or wood, for example bamboo. The stem may have a smooth or rough surface on the collecting surface.

A device according to the invention is particularly well suited to collecting hair fibers from hair.

The mass of the wand is in particular less than or equal to 15 g, preferably less than or equal to 10 g, more preferably less than or equal to 5 g.

Such a mass allows precise handling of the wand and thus facilitates collection.

The invention also relates to a method for collecting hair fibers, in particular using a wand according to the invention, comprising the following successive steps:

(1) selecting the desired quantity of hair fibers to be collected, with the distal end of a stem, in particular a prong of a wand according to the invention;

(2) optionally, evaluating the quantity collected, preferably by using the aforementioned gauge, and possibly adjusting the quantity of fibers to be collected;

(3) winding around the stem the hair fibers selected in step (1), and optionally adjusted, over a length of fiber greater than or equal to 1 cm;

(4) cutting off the hair fibers in order to keep the fibers wound on the stem;

(5) preferably, inserting the hair fibers held by the stem into a container, optionally inserting both the hair fibers and the stem on which the hair fibers are wound into the container, the stem optionally being able to act as a stopper for the container after insertion.

The method is preferably implemented using a wand according to the invention, as defined above, but, as a variant, a twist-key can opener and a comb, or a crochet hook and a comb, may be used.

Preferably, before step (1), the method according to the invention comprises a prior step consisting in isolating a set of hair fibers using a comb, and, in step (1), the collected fibers are selected from this set.

The number of hair fibers selected in step (1) may be greater than or equal to 5 and less than or equal to 15, particularly between 10 and 15 inclusive.

Preferably, step (2) is implemented.

The evaluation of the quantity of hair fibers to be collected may comprise positioning the hair fibers, for example by hand or by sliding them along the stem, in the aforementioned gauge. If the hair fibers fill the gauge, the quantity of hair fibers selected corresponds to the quantity necessary for the test, if the hair fibers overflow from the gauge, the quantity of hair fibers selected is greater than the quantity of hair fibers necessary, and if the gauge is not completely full, the quantity of hair fibers selected is less than the recommended quantity of hair fibers.

If necessary, the quantity of hair fibers selected is adjusted before they are collected.

During the use of a wand according to the invention, the hair fibers may be slid into the slot after step (1), preferably after step (2), and before step (3). The operator may easily wind the grouped hair fibers around the stem.

In step (3), the hair fibers selected are preferably wound over a length of fibers greater than or equal to 5 cm.

Preferably, the hair fibers selected are wound over their length until a non-wound length of fibers greater than or equal to 1 cm, preferably substantially equal to 1 cm, is left.

In particular, when the method is implemented in order to collect hair fibers from the head of an individual, the hair fibers may be wound up to 1 cm from the root. In addition, the hair fibers are preferably collected under the occipital bone of the head, the individual being in a seated or standing position and keeping their head straight. Preferably, after step (3) and before step (4), the wound hair fibers are trapped on the stem, for example using a retaining element as defined above.

This retaining element may be positioned on the fibers by sliding it from the distal end of the stem toward the proximal end thereof. The retaining element may be arranged so that it reaches an immobilized position on a larger section of the distal portion, or on a protrusion present on the stem.

Alternatively, the retaining element may be permanently present on the stem, for example being retained thereon by two end stops. In this case, the hair fibers are at least partially wound between these stops in step (3), and then the operator slides the retaining element onto the wound fibers so as to immobilize them.

The method preferably comprises a step (5) of inserting hair fibers into a container, for example a test tube or a flask.

The hair fibers may be inserted into the container while being kept immobilized on the stem. Alternatively, the hair fibers are released from the stem at the moment of insertion into the container. According to another aspect thereof, the invention further relates to a collecting kit comprising a wand according to the invention packaged with a reactant. Alternatively, the collecting kit comprises another tool making it possible to collect the hair fibers, for example a crochet hook or a twist-key can opener.

The kit may comprise at least one flask comprising or intended to contain the reactant.

The flask may be prefilled or for topping up.

Brief description of the drawings

The various aspects of the invention will be better understood on reading the following detailed description of non-limiting exemplary embodiments thereof, and from examining the appended drawing, in which

[Fig 1] is a longitudinal cross section of an example of a heating device according to the invention,

[Fig 2] shows a heating element,

[Fig 3] shows the heating device in an open position (figure 3b) and in a closed position (figure 3b),

[Fig 4] is an exploded view of the heating device,

[Fig 5] shows a transverse cross section of the heating device,

[Fig 6] shows a top view and a bottom view of the support of the heating element,

[Fig 7] is a graph illustrating an example of a rate of heating,

[Fig 8] shows an example of a wand according to the invention,

[Fig 9] shows an enlargement of the distal portion of the wand in figure 8,

[Fig 10] is a transverse cross-sectional view along the line X-X of a wand as shown in figures 8 and 9,

[Fig 11] shows another example of a wand according to the invention, comprising a gauge,

[Fig 12] shows another example of a wand according to the invention, comprising a retaining element,

[Fig 13] is another example of a wand according to the invention,

[Fig 14] is another example of a wand according to the invention,

[Fig 15] illustrates steps of the collecting method according to the invention, [Fig 16] illustrates the evaluation of the quantity of hair fibers using the gauge, [Fig 17] schematically shows the insertion of a retaining element on the stem, [Fig 18] shows a collecting kit according to the invention,

[Fig 19] illustrates examples of twist-key can openers, and

[Fig 20] illustrates an example of a crochet hook.

In the remainder of the description, elements that are identical or have similar functions bear the same reference signs. Their description is not repeated for each of the figures, and only the main differences between the embodiments are mentioned.

Detailed description

Figures 1 to 6 illustrate an assembly 1 according to the invention, comprising a container 2 and a device 3 for heating the container.

The heating device 3 comprises a housing 30 having a base 35 and a lid 36, and a heating element 32 contained in the housing, defining a cavity 34 for receiving the container. The cavity 34 is arranged so as to make it possible to heat the container by dry conduction, that is, without liquid at the interface between the heating element and the container, unlike a water bath. The base comprises an upper portion 351 and a lower portion 35₂.

The container 2 may be, as illustrated, a tubular container, preferably exhibiting symmetry of revolution. Preferably, the container has a maximum outer diameter D greater than or equal to 2 cm and less than or equal to 3 cm.

The container may particularly be a test tube or a sample tube, in particular standard.

The container may be made from mineral glass or a thermoplastic material able to withstand the operating temperature, in particular polypropylene or polyethylene.

Preferably, the container is made from a material that is able to withstand the operating temperature and is chemically neutral.

Chemically neutral is given to mean a material that does not produce any chemical reaction when it is in contact with a composition intended to be introduced into the container. Preferably, the container is made from a transparent or semi-transparent material.

In certain embodiments, the container may be made from a metal alloy, which may be opaque. The nature of the material of the container may make it possible to improve the conduction of heat within the container.

The container may particularly be intended to contain a solution for performing a chemical test, requiring the heating of the solution to a given temperature and/or for a given duration.

The biological material to be analyzed may be inserted into the container, being constituted of hair fibers for example.

In particular, the assembly according to the invention may be arranged so as to allow the chemical analysis of hair.

The container may be closed by a thermally insulating stopper 22, as illustrated in figure 1. In particular, the stopper may be at least partially formed by a thermally insulating foam 22i. The stopper may comprise a central portion 222, for example made from an elastomer or a flexible, non-cellular plastic material, which is fastened to the neck of the container to close it, and a concentric outer portion 22i, formed by said insulating foam, which extends over more than the height of the central portion.

The height of the container and the height of the cavity are such that preferably more than 70%, better still more than 80%, even better still more than 90% of the container is contained in the cavity 34.

The outer surface of the portion of the container received in the cavity may come into direct contact with the heating element 32, allowing for the insertion clearance.

As illustrated in figure 2, the heating element 32 may comprise a heating sleeve 38 made up of a ceramic-coated resistor.

The heating element 32 may be connected to an electricity supply, via a connector 62.

The heating sleeve 38 may be a split collar as illustrated.

A clamping collar 40 may encircle the heating sleeve 38, the clamping collar adjusting the inner diameter d of the heating sleeve on production so that the container fits into the cavity of the heating element with sufficiently little clearance to allow the heating of the container by dry conduction and the insertion or removal of the container without force.

The clamping collar 40 may in particular be adjusted by tightening a screw 42. In addition, a thermistor 44 or any other temperature sensor may be positioned in direct contact with said screw 42. A ground wire 74 may be connected to the screw 42, to ensure electrical safety.

The heating element 32 may be arranged in a support 48 that thermally insulates the heating element from the housing, as illustrated. In particular, the support 48 may comprise a thermal insulator 46 at least partially encasing the heating element.

A thermal fuse 66 is preferably positioned in the lower portion of the support.

The bottom of the support may comprise a slot 68 having the general shape of an angular sector. The vertex of this sector is preferably situated substantially in the center of the bottom of the support. In addition, the slot 68 may comprise a widening 70 at the vertex of the sector. The opening angle 0 of the angular sector may be greater than or equal to 15° and less than or equal to 45°. Such a support 48 provides deformability and the possibility of adjusting its inner diameter by tightening a screw 72 engaging on two opposite posts of the support 48. The support may thus be tightened on the heating element.

The support 48 may be fastened, as illustrated in figure 6, to an upper portion of the housing 30, in particular the upper portion 351 of the base.

The support 48 is for example screwed to the upper portion of the base 35 by means of screws 50, as illustrated in figure 4.

The lid 36 is movable, as shown in figure 3, between an open position shown in figure 3a and a closed position shown in figure 3b.

The lid 36 may comprise a lateral opening 52.

The lid 36 may be pivotably mounted about an axis of rotation X substantially parallel to an axis of insertion Y of the container into the cavity of the heating element. The lid pivots in a horizontal plane.

A contact switch 54 may be positioned in the heating device, as shown in figure 5, this switch being fastened for example to the lower portion 352 of the base, the switch 54 being arranged so that the closed state of the switch is triggered by rotating the lid, when said lid pivots into the closed position, the control circuit of the heating element being configured so as to prevent heating when the switch is open.

The lid 36 may be fastened to a rod 56 positioned inside the housing and comprising a cam 58 intended to come into contact with the switch 54 when the lid is in the closed position, the switch being placed in the closed position by the cam 58.

Preferably, the device comprises a temperature controller 60 configured to control the heating element so as to heat the container to a predefined temperature, and maintain this predefined temperature for a predetermined time period, the temperature being in the range [70°C ; 110°C], better still in the range [90°C ; 100°C], for a time period greater than or equal to 3 minutes and/or less than or equal to 10 minutes.

The temperature controller 60 may comprise a microcontroller, which controls, for example by means of an optocoupler, a power component, making it possible to control the electricity supply to the heating element as a function of the measurements detected by the thermistor and of the control law. The power component may be an optotriac.

The heating device may comprise a visual or audible indicator 64 informing the user about the operating state of the device. For example, the visual or audible indicators may indicate that the device is heating up, that the predefined temperature has been reached, that the predetermined time period has elapsed, or that the device is open. In particular, the visual or audible indicators may originate from a screen, an LED, or a buzzer.

The temperature controller may in particular be a PID (proportional - integral - derivative) controller, the proportional gain Kp of which is in particular between 0.2 and 0.4, and the proportional gain Ki of which is in particular between 0.05 and 0.15.

The PID controller makes it possible to have a rate of heating in the form of a ramp R. The graph in figure 7 shows, with a measurement interval of 500 ms, curves Cl, C2, C3 that show the change in the temperatures obtained in the contents of the container over time during the operation of the heating device illustrated in figures 1 to 6. Curves Cl to C3 were obtained during three successive tests aimed at heating the container to a temperature setpoint of 100°C and then maintaining this temperature for a duration of at least 5 minutes. Curve C4 corresponds to the difference between curves Cl and C3. These curves show that the predefined temperature of 100°C may be reached relatively quickly and maintained, with a degree of accuracy of approximately 10°C.

Figures 8 to 10 illustrate a wand 100 for collecting hair fibers according to the invention, comprising a stem 110 that extends along a longitudinal axis XX and comprises, at a distal end, a slot 118 extending substantially longitudinally so as to form a first prong 112 and a second prong 114, the length Ln of the first prong measured along the axis XX between its free end and the bottom of the slot 118 being less than the length Lu of the second prong.

The wand advantageously has a length LI of between 10 cm and 20 cm, preferably between 13 cm and 17 cm, preferably substantially equal to 15 cm.

The wand 100 may be used to collect hair fibers from the head of an individual, for example in order to test the hair before dyeing by a hairdresser.

The stem has a main portion 110c that preferably has a constant transverse cross section, for example circular.

This main portion may extend over a length Lio_c greater than half of the total length Li of the wand, better still greater than two thirds of its length Li, even better still greater than three quarters of the length Li.

The slot 118 may have a substantially constant width, as illustrated in figure 2. This width di8 may be greater than or equal to 1 mm and/or less than or equal to 2 mm.

The slot 118 may be less wide than the maximum thickness en of the prong 112 and also less wide than the maximum thickness eu of the second prong 114, as shown in figure 10.

In one variant, the thickness en of the first prong is equal to the thickness eu of the second prong at least at one point on the axis XX.

The length Ln of the first prong is less than the length Lu of the second prong.

The length Ln of the first prong may be between 5 mm and 2 cm, preferably between 5 mm and 1 cm inclusive.

The length Lu of the second prong may be between 8 mm and 8 cm, preferably between 1 cm and 4 cm inclusive.

The length Ln of the first prong may be less than or equal to half of the length Lu of the second prong, better still less than or equal to one third of the length Lu of the second prong, even better still less than or equal to one quarter of the length Lu of the second prong.

Preferably, as illustrated in figure 9, the prongs 112 and 114 each have a tapered shape. The thickness of the first prong and/or the thickness of the second prong may thus be non-constant. In particular, the thickness of the first prong and/or the thickness of the second prong may decrease toward the distal end Idist of the wand.

Preferably, the distal end of the first prong 112 and/or the distal end of the second prong 114 is truncated.

The thickness of the first prong may be between 0.5 mm and 5 mm, preferably between 1 mm and 2.5 mm inclusive.

The thickness of the second prong may be greater than or equal to 2.5 mm, preferably greater than or equal to 5 mm.

Preferably, the thickness of the first prong is less than the thickness of the second prong, for a given transverse cross section.

The wand 100 may comprise a generally tapered distal portion 20, for example having a generally truncated conical envelope surface, the prongs 112 and 114 forming part of this distal portion 120.

The distal portion may extend over a length L20 greater than the length L12 of the first prong and/or the length L14 of the second prong.

Preferably, the distal portion 120 extends over a length L20 greater than or equal to 5% of the length of the wand Li, better still greater than or equal to 10% of the length Li, even better still greater than or equal to 15% of the length Li.

The maximum diameter of the distal portion may be greater than or equal to 5 mm and/or less than or equal to 10 mm, preferably less than or equal to 8 mm.

The distal portion may have a minimum outer diameter greater than or equal to 3 mm and/or less than or equal to 5 mm.

Steps of a collecting method using such a wand are shown in detail in figure 15.

A comb may be used to initially isolate a set of hair fibers. In a first step (1) of the method, the second prong then allows the operator to precisely select the hair fibers to be collected from this set, by spearing the root of the hair with the free end of the prong, then performing a circular motion with the stem around the fibers while keeping the free end of the prong substantially immobile. The operator may then slide the selected hair into the slot 118 between the two prongs 112, 114.

Once the fibers are engaged in the slot, the operator slides the stem along the hair fibers thus selected while keeping them in the slot and moving the wand away from the scalp, then winds the fibers around the stem or around the prongs, thus forming a coil 152, which corresponds to step (3).

Preferably, the fibers are wound over a length of between 1 cm and 10 cm inclusive. The fibers may in particular be wound over a length corresponding to their total length minus a cutting value of between 0.5 cm and 2 cm, in particular a cutting value substantially equal to 1 cm.

In step (4), the fibers are then cut off, preferably at point situated between the root and the stem.

Preferably, the hair fibers are cut off at a distance d_r greater than or equal to 0.5 cm from their root, and preferably less than or equal to 2 cm, better still less than or equal to 1 cm.

The hair fibers may then be placed in a container 60, in step (5), if they are intended to be placed in contact with a reactant or sent to a remote site for analysis.

The container may be a test tube or a flask, optionally a postal envelope.

The container may contain a reactant.

Once collected and placed in the container, the operator may push the hair fibers down, so as to position them correctly inside said container, for example to minimize the quantity of reactant used.

To this end, the wand may advantageously comprise a proximal portion 124 having a widened diameter and the end l_prox of which defines a substantially flat surface S.

The proximal portion 124 may have a right circular cylindrical envelope surface of axis X.

The proximal portion 124 may be integrally formed with the stem, or be attached thereto.

It may be beneficial to extract the hair fibers from the container once the analysis has been performed, for example so as to allow the recycling of the container.

It is then preferable to avoid any contact between the reactant present in the container and the operator. The wand may advantageously comprise a hook 126 making it possible to extract the hair fibers from the container.

This hook 126 may be formed, as shown in figure 8, in the proximal portion 124 of the stem. The hook 126 may be formed between substantially parallel opposite surfaces S241 and S242 that are inclined by angles a and P respectively, these angles each being for example substantially 45° relative to the longitudinal axis XX.

The hook 126 may alternatively be formed by a stud 126’ extending axially toward the distal end as shown in figure 14.

Figure 12 shows that the hook and the slot may each have a symmetrical shape relative to a median plane containing the axis XX, parallel to the plane of figure 12.

The variant in figure 13 illustrates the option of producing the proximal portion without a hook.

Preferably, after step (1) and before step (4), the operator performs a step of checking the quantity of hair fibers being collected. Preferably, this checking step is performed during the implementation of a step (2).

To this end, the wand may comprise a gauge 122 as illustrated in figure 11.

This gauge 122 may be a recess formed in the stem, and preferably extends along an axis YY perpendicular to the axis XX.

The gauge 122 may be a notch having a V-shaped cross section as illustrated, or as a variant it may have any other concave shape having a predefined cross section, defining a space for receiving the fibers.

The gauge 122 may be formed at a distance d from the bottom of the slot 118, this distance d preferably being greater than or equal to 5 mm and/or less than or equal to 2 cm.

The maximum width L22 of the gauge is for example between 0.5 mm and 1.5 mm, preferably being substantially equal to 1 mm.

The length I122 of the gauge depends on its depth and is for example less than half of the circumference of the stem.

The maximum depth of the gauge 122 (measured half way along its length) is for example between 0.7 mm and 1 mm, this depth being measured radially.

As illustrated in figure 16, the operator may position the hair fibers 150 in the gauge 122, for example bringing their ends into the gauge. In some particular embodiments, the operator may slide the hair fibers 150 into the gauge during the implementation of step 3, when the operator starts to wind the hair fibers around the stem, step (2) then being performed simultaneously with step (3). This advantageously makes it possible to avoid all contact with the hair fibers.

The operator may optionally check by touch whether the gauge is full by passing their finger over the surface thereof Preferably, the operator checks visually whether the hair fibers 150 are filling the gauge 122.

In order to prevent any loss of hair fibers during the transfer of the fibers from the collection location to the container, the wand may comprise a retaining element 130, as illustrated in figure 12.

The retaining element 130 may slide along the stem, and has an annular shape for example.

This retaining element 130 is configured so as to make it possible to retain the fibers on the wand during collection, the hair fibers being held gripped between the retaining element 130 and the stem 110.

As illustrated in figure 17, after winding the hair fibers on the stem, the operator may position the retaining element on the fibers wound on the wand by sliding it from the distal end toward the proximal end of the wand.

Generally, the wand 100 may be at least partially made from injected plastic and/or wood and/or a plastic and/or metal material.

The wand may be machined and/or molded.

In particular, the wand may be made from an inert plastic material.

The wand may be manufactured by molding, in particular injection molding. It may optionally be manufactured by 3D printing.

The surface state of the wand may optionally be adjusted by a treatment such as sanding, so as to obtain the desired adherence to the hair.

The stem 110 may be at least partially covered with a coating, so as to provide a smooth surface and/or a slightly rough surface and/or an adherent surface; in particular, the first and/or second prong may be at least partially covered with such a coating.

The first prong and/or the second prong may be at least partially provided with spikes on their surface, the spikes extending radially, preferably being flexible. At least one portion of the wand, preferably the first and/or second prong, may be a pale color, in particular a beige, pastel or white tone.

The invention also relates to a collecting kit 200 comprising a container 160, a wand 100 according to the invention, and optionally a package 162.

This container is preferably a flask.

The kit may comprise a reactant. In particular, the reactant may be intended to test fibers before the application of a treatment product to the hair, for example a hair dye.

The reactant may be contained in one or more flasks.

The reactant may be ready-to-use or require preparation by mixing the contents of several flasks and/or topping up with an aqueous solution.

The invention is not however limited to a kit comprising a wand according to the invention, or to the implementation of the collecting method using a wand according to the invention.

In particular, the kit may comprise a twist-key can opener 64 or a crochet hook instead of the wand according to the invention.

The collecting method may thus be implemented using a twist-key can opener or a crochet hook.

A twist-key can opener conventionally comprises a stem 110’, the latter comprising at a distal end two prongs 112’; 114’, separated by a slot 118’, and at a proximal end a portion forming a loop 124’ with a flat head 128’, as shown schematically in figure 18.

A twist-key can opener is not a wand according to the invention, due to the presence of the large loop at the end. In addition, the largest dimension in transverse cross section is situated on the loop 124’ and is greater than 1/5 of the length of the twist-key can opener.

As a variant, a crochet hook 166 may be used to implement the method according to the invention.

A crochet hook conventionally comprises a stem 110”, the latter comprising at its distal end a hook 140”, as schematically shown in figure 17.

Claims

1. An assembly (1) made up of a container (2) and a device (3) for heating the container, the heating device comprising:

- a housing (30);

- a heating element (32) contained in the housing and defining a cavity (34) for receiving the container, intended to heat the container by dry conduction; and

- a lid (36) intended to cover the container present in the cavity (34).

2. The assembly as claimed in the preceding claim, wherein the container (2) is a tubular container having an outer diameter (D) greater than or equal to 2 cm and less than or equal to 3 cm.

3. The assembly as claimed in one of claims 1 and 2, wherein the housing (30) comprises a base (35) having an opening through which the container is intended to be introduced into the base, the lid (36) being hinged on the base between an open position and a closed position.

4. The assembly as claimed in claim 3, wherein the lid (36) is pivotably mounted about an axis of rotation (X) substantially parallel to an axis of insertion (Y) of the container into the base and into the cavity of the heating element.

5. The assembly as claimed in one of claims 3 and 4, wherein the heating device comprises a contact switch (54) arranged so that the closed position of the switch is triggered by rotating the lid, when the lid pivots into the closed position, the switch being configured so as to prevent heating when the switch is open.

6. The assembly as claimed in the preceding claim, wherein the lid is fastened to a rod (56) positioned inside the housing and comprises a stop element (58) intended to come into contact with the switch when the lid is in the closed position, the switch being in the closed position when it is in contact with the stop element.

7. The assembly as claimed in any one of claims 3 to 6, wherein the lid (36) comprises a lateral opening (52).

8. The assembly as claimed in any one of the preceding claims, wherein the heating element (32) comprises a heating sleeve made up of a ceramic-coated heating resistor.

9. The assembly as claimed in the preceding claim, the heating sleeve being a split collar.

10. The assembly as claimed in one of claims 8 and 9, wherein the heating element comprises a collar (40) for clamping the heating sleeve, the clamping collar adjusting the inner diameter of the heating sleeve so that the container fits into the cavity of the heating element with sufficiently little clearance to allow the heating of the container by dry conduction.

11. The assembly as claimed in the preceding claim, wherein the collar is adjusted by tightening a screw, a temperature sensor (44) such as a thermistor being positioned in direct contact with said screw.

12. The assembly as claimed in any one of the preceding claims, comprising a temperature controller (60) configured to heat the container to a predefined temperature, and optionally maintain this predefined temperature for a predetermined time period, the temperature being in the range [70°C ; 110°C], better still in the range [90°C ; 100°C], this temperature preferably being maintained for a time period greater than or equal to 3 minutes and/or less than or equal to 10 minutes.

13. The assembly as claimed in claim 12, wherein the temperature controller (60) is a PID (proportional - integral - derivative) controller, the proportional gain Kp of which is in particular between 0.2 and 0.4, and the proportional gain Ki of which is in particular between 0.05 and 0.15.

14. The assembly as claimed in any one of the preceding claims, comprising a thermally insulating stopper (22) of the container.

15. The assembly as claimed in any one of the preceding claims, wherein the heating element is arranged in a support (48) that thermally insulates the heating element from the housing, the support being fastened to an upper portion (351) of the housing, and in particular, when the housing comprises a base and a lid, the support being fastened to an upper portion of the base.

16. The assembly as claimed in the preceding claim, wherein a fuse (66) and a ground wire are positioned in a lower portion of the support.

17. The assembly as claimed in one of claims 15 and 16, wherein the base of the support comprises a slot (68) having the general shape of an angular sector, the vertex (70) of the angular sector being situated substantially in the center of the bottom of the support, and wherein the slot preferably comprises a widening at the vertex of the angular sector.

18. The assembly as claimed in the preceding claim, wherein the opening angle (0) of the angular sector is greater than or equal to 15° and less than or equal to 45°.

19. A hair fiber collecting wand (100), comprising a stem (110) that extends along a longitudinal axis (XX) and comprises in a distal portion a slot (118) extending substantially longitudinally so as to form at least one first prong (112) and at least one second prong (114), the length of the first prong being less than the length of the second prong, comprising a gauge (122) extending transversely to the longitudinal axis XX.

20. The collecting wand as claimed in the preceding claim, wherein the distal portion (20) of the stem is beveled and/or truncated.

21. The wand as claimed in one of claims 19 and 20, comprising a retaining element (130) for retaining the hair fibers on the stem.

22. The wand as claimed in any one of claims 19 to 21, wherein the stem has a substantially cylindrical overall shape.

23. The wand as claimed in any one of claims 19 to 22, comprising a proximal portion (124) having a widened cross section relative to the cross section of a median portion of the stem.

24. The wand as claimed in any one of claims 19 to 23, wherein at least one portion of the wand, preferably the first and/or second prong, is a pale color, in particular a beige, pastel or white tone.

25. The wand as claimed in any one of claims 19 to 24, wherein said wand is at least partially made from injected plastic and/or wood.

26. A collecting kit (200) comprising a wand (100) as claimed in any one of claims 19 to 25 and at least one container (160), in particular a container holding a reactant making it possible to test the effect of a dye on the hair.

27. A method for collecting hair fibers, in particular using a wand as claimed in any one of claims 19 to 25 or a kit as claimed in claim 26, comprising the following successive steps:

(1) selecting a desired quantity of hair fibers to be collected, with the distal end of a stem, in particular a prong of a wand as claimed in any one of claims 19 to 25; (2) optionally, evaluating the quantity collected, preferably by using the aforementioned gauge, and possibly adjusting the quantity of fibers to be collected;

(3) winding around the stem the hair fibers selected in step (1), and optionally adjusted, over a length of hair fiber greater than or equal to 1 cm; (4) cutting off the hair fibers in order to keep the fibers wound on the stem;

28. The method as claimed in the preceding claim, implemented using a wand as claimed in one of claims 19 to 25, a twist-key can opener and a comb, or a crochet hook and a comb.

29. The method as claimed in one of claims 27 and 28, wherein the number of hair fibers selected is greater than or equal to 5 and less than or equal to 15, and preferably between 10 and 15.