EP3439791B1 - Assembly for dispensing a fluid product - Google Patents

Description

The present invention relates to a fluid dispenser assembly comprising a fluid reservoir, a dispensing member and a dispensing orifice, the reservoir comprising a piston displaceable in leaktight sliding in a sliding barrel over a maximum stroke defined between a position starting point corresponding to a substantially full state of the tank and an arriving position corresponding to a substantially empty state of the tank. Thus, the assembly makes it possible to apply a fluid product to target such as the skin. The preferred field of application of the present invention is of course that of cosmetics, but may also be that of pharmacy.

In the prior art, there are already many distributors of this type, comprising a reservoir provided with a piston, of the follower or pusher type. When the tank is empty, the user is simply informed by the non-delivery of fluid after one or more actuations. It is possibly possible to make the tank from transparent material, so that the user sees what remains in the tank.

We also know the document WO2015 / 170048 which describes a distribution assembly implementing a reservoir provided with a follower piston.

We also know the documents US2012 / 267390 , JP2007 / 153415 and US2012 / 267391 which describe the systems which make it possible to give a visual indication of the positioning of a follower piston in a sliding barrel. However, these systems are all passive, so that the user must consult the visual indication, but does not receive information.

The present invention aims to improve these fluid dispensing assemblies of the prior art by giving the user clear, reliable and perceptible information on the filling / emptying state of the piston tank.

To do this, the present invention provides a fluid dispenser assembly comprising a fluid reservoir, a dispenser member and a dispensing orifice, the reservoir comprising a piston displaceable in sealed sliding in a sliding barrel over a maximum stroke. defined between a starting position corresponding to a substantially full state of the reservoir and an arrival position corresponding to a substantially empty state of the reservoir, characterized in that it further comprises physical property detection means having a detection field restricted with respect to the maximum stroke of the piston, the physical property detection means being arranged outside the fluid reservoir to detect remotely, through the sliding barrel, a determined physical property which falls within the scope of restricted detection covering a warning position of the piston which is more pr oche from the arrival position than from the departure position, the piston carrying said determined detectable physical property, the detection means delivering, in response to a detection of the physical property, at least one alert signal perceptible by a user . Thus, remote sensing technology is used to give clear, reliable and perceptible information to the user, who therefore does not need to constantly check the filling / emptying state of the tank.

Advantageously, the sliding barrel is disposed between the piston and the detection means, the sliding barrel not preventing the detection of the physical property determined by the detection means. In other words, the material constituting the barrel is transparent to the detection means and / or the physical property.

The alert position is reached when the piston has completed more than 75%, or more than 90%, or even 100%, of its maximum stroke from the starting position. However, it is also possible to envisage other additional alert positions, for example at half the maximum stroke of the piston, or even at a quarter of its stroke. The piston can for example reach several successive alert positions as it moves towards the arrival position, these alert positions being successively detected by the detection means, which advantageously deliver several distinct respective warning signals.

According to an advantageous embodiment, the detection means are mounted on an integrated circuit plate. According to a practical embodiment, the fluid reservoir, the dispensing member and the dispensing orifice are formed by a dispenser which is removably insertable in a box forming an application surface and integrating the detection means advantageously mounted on an integrated circuit plate, which extends substantially parallel to a plane passing through the fluid reservoir, the dispensing member and the dispensing orifice. The distribution assembly then has a configuration close to or identical to that of the document WO2015 / 170048 .

According to an advantageous aspect, the detection means are positioned in contact with, or in close proximity to, the sliding barrel, so as to reduce the distance between them and the piston.

According to one embodiment, the detection means can comprise a magnetic field sensor and the piston is provided with a magnet generating a magnetic field as a determined detectable physical property. The magnet may have a volume of less than 40 mm3, advantageously less than 30 mm3, and more advantageously still less than 20 mm3. The magnet can be annular with an outside diameter slightly smaller than the maximum outside diameter of the piston, so that the magnet is close to the sliding barrel.

Alternatively, the piston is produced by injecting plastic material loaded with magnetic particles.

According to another embodiment, the detection means comprise a determined wavelength sensor and the piston emits waves having said determined wavelength. The wavelength determined can for example be red and the piston is at least partially red.

In a common application form, the piston is a follower piston which moves when the fluid in the tank is under vacuum.

The spirit of the invention resides in the fact of remotely detecting the passage of the piston which moves in the barrel of the tank to provide visual and / or audible information to the user on the state of filling / emptying of the tank. . Remote detection can use any technology, such as induction (magnetic field detection or magnetic field disturbance detection), optics (color, reflection, refraction, diffraction), l capacitive effect, ultrasound, hall effect, Faraday effect, resistance variation, etc.

The invention will now be described in more detail with reference to the accompanying drawings, giving by way of nonlimiting example, an embodiment of the invention.

• La figure 1 est une vue en section transversale verticale à travers un ensemble de distribution et d'application de produit fluide de l'invention, sensiblement à l'échelle 1,
• La figure 2 est une vue fortement agrandie de la partie supérieure de la figure 1,
• La figure 3 est une vue en section transversale horizontale le long de la ligne de section A-A de la figure 2,
• La figure 4 est une vue en perspective explosée de l'ensemble de distribution et d'application des figures précédentes,
• La figure 5 est une vue similaire à celle de la figure 1, en l'absence de distributeur de produit fluide,
• La figure 6 est une vue en section transversale verticale à travers un distributeur de produit fluide selon l'invention,
• La figure 7 est une vue de dessus du distributeur de la figure 6,
• La figure 8 est une vue en perspective explosée du distributeur des figures 6 et 7,
• La figure 9 est une vue en coupe schématique à travers un ensemble de distribution et d'application de produit fluide selon un deuxième mode de réalisation de l'invention,
• La figure 10 est une vue agrandie du piston de la figure 9, et
• Les figures 11 et 12 sont des vues similaires à la figure 10 pour deux autres variantes de réalisation pour un piston selon l'invention.

In the figures:

• The figure 1 is a vertical cross-section view through a dispensing and application assembly of the fluid product of the invention, substantially on scale 1,
• The figure 2 is a greatly enlarged view of the upper part of the figure 1 ,
• The figure 3 is a horizontal cross-sectional view along the section line AA of the figure 2 ,
• The figure 4 is an exploded perspective view of the distribution and application assembly of the preceding figures,
• The figure 5 is a view similar to that of the figure 1 , in the absence of a fluid dispenser,
• The figure 6 is a vertical cross-section view through a fluid dispenser according to the invention,
• The figure 7 is a top view of the dispenser of the figure 6 ,
• The figure 8 is an exploded perspective view of the dispenser Figures 6 and 7 ,
• The figure 9 is a schematic sectional view through a fluid dispensing and application assembly according to a second embodiment of the invention,
• The figure 10 is an enlarged view of the piston of the figure 9 , and
• The Figures 11 and 12 are views similar to the figure 10 for two other alternative embodiments for a piston according to the invention.

We will begin by illustrating the present invention with reference to Figures 1 to 8 which represent a set of distribution and application similar to that of the document WO2015 / 170048 , with additional remote detection. This dispensing and application set has an elongated or slender shape which can be similar to that of a pen or a felt. It can also be noted that its cross section is not constant, since it varies from bottom to top significantly. In this case, near its lower end, the dispensing and application assembly has a rather round or circular cross section, while at the level of the cutting line AA, which is rather located near the he upper end, the dispensing and application assembly has an ovoid cross section ( Figure 3 ). The upper face of the assembly forms an application surface S which has an inclination or slope towards one side.

Referring to the figure 4 , we can see the different components of the distribution and application assembly of the invention. It can first of all be noted that it comprises three separate main entities, namely a distribution entity D, a receiving entity B and an application entity A. The distribution entity D, which is a product distributor fluid, is received, advantageously removably, inside the receiving entity B, which comprises a one-piece receiving body 1 whose interior is hollow. The application entity A is mounted on and in the body 1, advantageously removably. Thus preferably, the two entities D and A are received removably on and in the body 1 from these two opposite ends 17 and 12, respectively. This is the overall architecture of the distribution and application assembly according to the invention.

In more detail, the body 1 of the receiving entity B is open at its two upper 12 and lower 17 ends to be able to accommodate the entities A and D. The lower end 17 is advantageously internally threaded for receive by screwing a removable bottom 7. The latter has the shape of a small bucket with a bottom wall 73 and a cylindrical side wall 71 whose upper part forms a thread 72 whose pitch corresponds to that of the lower end 17 of the body 1. It may be noted that the removable bottom 7 is provided above its lower wall 73 with a piece of elastic material 74, which may be a foam or an elastomer. The removable bottom 7 internally forms a space 70 which communicates upwards with the interior of the body 1 which itself defines a reception space 1a. Beyond this reception space 1a, the interior of the body 1 is divided into two compartments 1b and 1c by a partition 13. The compartment 1b extends axially in the extension of the space 1a, while the compartment 1c extends laterally, at the level where the body 1 defines its ovoid shape. The lower end of the partition 13 forms a latching edge 14 as will be seen below. The body 1, at the level of the compartment 1b is provided with a lateral pusher 15 which is movable transversely to the longitudinal axis of the receiving body 1. The displacement of the pusher 15 can be done by pure translation or by elastic deformation. One can for example provide for overmolding the pusher 15 on the receiving body 1 with an elastomeric material. As a variant, it is also possible to provide a pusher 15 which moves completely independently of the body 1. It is also possible to provide a simple opening in place of the pusher 15. It may also be noted that the partition 13 extends as far as possible from the upper end 12. The receiving body 1 can very simply be produced by injection molding of plastic material, or even of metal.

The application entity A here results from the association of an application head 2 and a wave generation module 3. The application head 2, as can be seen in the Figures 1 and 2 , comprises an axial housing 22 formed by a cylindrical tube whose cross section has a complex geometric shape, for example that of a crescent. This housing 22 is connected upwards to an application surface area 21 which is here formed with two openings, namely a first opening corresponding to the mouth of the housing 22 and a second opening for the module 3. More specifically, the module 3 comprises an application surface section 31 which closes the corresponding opening in the head 2 so as to continuously complement and smooths the application surface area 21 of the head 2. In other words, the module 3 fits into the opening of the application head so that the application surface section 31 of the module 3 completes the range of application surface of the head 2 without creating discontinuity, protrusion or depressions. Consequently, the assembly of the module 3 and of the head 2 makes it possible to create an application surface S, the only opening of which, at this stage, is formed by the mouth of the housing 22. We can notice on the Figures 1 and 2 that the application surface section 31 extends at the level of the most inclined part of the application surface S. The application head 2 also includes a peripheral skirt 23 which fits in the upper end 12 of the hollow body 1. On the other hand, the wave generation module 3 extends inside the reception space 1c, and advantageously has a latching profile 34 capable of cooperating with the lower edge 14 of the partition 13. In this way, the application entity A can be mounted in a perfectly stable manner on and in the hollow body 1.

The wave generation module 3 makes it possible to generate any type of wave or electromagnetic, vibratory radiation, etc., such as, for example, visible light, infrared, ultraviolet, or even microwave, etc. or even ultrasound or mechanical vibrations. Module 3 can also generate heat or cold (thermal waves) to impart a hot or cold effect on contact with the skin.

The fluid dispenser or distributor D comprises a fluid reservoir 4, a pump 5 and a dispensing nozzle 6, as can be seen more clearly on the figures 6 to 8 .

The reservoir 4 may for example be in the form of a sliding barrel 41 in which is received a follower piston 42 which is adapted to slide in the barrel 41 as fluid is extracted from the tank. The top of the barrel 41 forms a neck 45. Instead of this particular reservoir, one can also imagine a simpler reservoir without variation in useful volume, or even a reservoir with a flexible pocket.

The pump 5 comprises a fixing ring 54 allowing it to be mounted on the neck 45 of the reservoir 4. The pump 5 comprises a pump chamber 50 provided at its lower end with an inlet valve 51, for example in the form of a slit shutter. At its upper end, the pump chamber 50 comprises an outlet valve 52, which can for example also be produced in the form of a slotted shutter. In addition, the pump chamber 50 comprises a lateral actuator 53 which makes it possible to reduce the useful volume of the pump chamber 50 and thus to discharge fluid product through the outlet valve 52. The lateral actuator 53 is movable perpendicular to the longitudinal axis X of the distributor D. The displacement can be done translatively or by elastic deformation. In the embodiment used to illustrate the present invention, the actuator 53 is in the form of a flexible wall of the pump chamber 50 which has been produced for example by a bi-injection or overmolding process. The pump 5 can thus be qualified as a flexible membrane pump, in the sense that one acts directly on a movable wall of the chamber to put the fluid product under pressure. At its upper end, the pump 5 forms a mounting well 56 for the dispensing nozzle 6. This mounting well 56 is advantageously provided with coding means 55, for example in the form of a projecting profile or of a recess, making it possible to impose the angular orientation of the nozzle 6 in the well 56.

The dispensing nozzle 6 thus comprises a mounting heel 65 which is engaged, and advantageously snapped into, inside the mounting well 56. The mounting heel 65 comprises a keying profile which adapts perfectly in the means of coding 55 of the well 56, in order to impose the angular orientation of the dispensing nozzle 6 on the pump 5. In this way, the nozzle is always oriented in the same way relative to the lateral actuator 53, which extends only on one side of the pump 5. Above of this mounting heel 65, the dispensing tip 6 forms an insertion appendage 63 whose cross section has a shape corresponding to that of the housing 22 formed by the application head 2. This shape is more clearly visible on the figure 7 : it is similar to a shape of a crescent. The side wall of the insertion appendage 63 may be cylindrical, although not circular over its entire height. As a variant, one or more protruding sealing bead (s) can be provided for making a seal inside the housing 22. At its upper end, the appendage 63 forms a substantially planar outlet surface 61 which is pierced with a dispensing orifice 62, forming the outlet of an outlet duct 60 which passes through the appendix 63 and the mounting heel 65, as can be clearly seen on the figures 2 and 6 .

Once the dispensing nozzle 6 is mounted on the pump 5, as visible on the figure 6 , it can be seen that the outlet valve 51 communicates directly with the outlet duct 60. Thus, by pushing in the lateral actuator 53, the useful volume of the pump chamber 50 is reduced, and the fluid under pressure is discharged to through the outlet valve 52, from where it can flow through the outlet conduit 60 to the dispensing orifice 62 located at the outlet surface 61. As soon as the pressure is released on the lateral actuator 53, the outlet valve 52 closes and the inlet valve 51 opens under the effect of the vacuum created in the pump chamber 50, thus making it possible to suck fluid product coming from the reservoir 4, the follower piston 42 of which then moves towards the pump 5.

As can be understood from the figure 4 , the distributor entity of the distributor D is inserted inside the hollow body 1 through its lower end 17, after removal of the removable bottom 7. The distributor D is thus inserted axially through the space 1a, then through the space 1b until the dispensing nozzle 6 penetrates inside the housing 22 of the application head 2. As previously explained, it is necessary to angularly orient the dispenser D so that its appendage d insertion 63 engages inside the housing 22. The angular orientation is preferably unique. It is then possible to fully engage the appendix 63 inside the housing 22 until the outlet surface 61 reaches the level of the application surface S so as to complete it. This is visible on the figure 2 . It can be seen that the outlet surface 61 comes perfectly flush with the surface of the application surface 21 of the head 2 so as to complete it. In the end, only the dispensing orifice 62 breaks the continuity of the application surface S. To guarantee the full engagement of the appendix 63 in the housing 22, use is made of the removable bottom 7, the flexible material of which 64 comes into contact with the bottom of the reservoir 4 to push it upwards, and seal the housing 22. It should also be noted in this regard that the lower end of the reservoir 4 projects from the hollow body 1 when the bottom removable 7 is removed, so that the dispenser can easily be grasped by its reservoir 4 to extract it from the hollow body 1. As a result, the dispenser D is removably received inside the hollow body 1 and the head 2. It can also be noted that the imposed angular orientation of the appendix 63 inside the housing 22 allows the lateral actuator 53 to be placed opposite the pusher 15 of the hollow body 1.

On the figure 3 , we can see the arrangement of the various constituent elements of the distribution and application assembly of the invention at the level where it has its ovoid shape. It can for example be seen that the generation module 3 is received inside the compartment 1c which is delimited by the partition 13 which partially surrounds the pump 5, the lateral actuator 53 of which is covered by the lateral pusher 15. On can thus say that the pump 5 is arranged between the module 3 and the pusher 15 inside the hollow body 1.

With such a design, the application entity A is removably received on and in the reception entity R. On the other hand, the distributor distribution entity D is also removably received inside of the receiving entity R and inside the housing 22 of the application entity A. In this way, the distributor D and the application entity A can be replaced at will as required. One can for example imagine that a particular distributor distributing a particular fluid product is associated with a particular application entity. It then suffices to mount the two entities A and D in the receiving entity R to constitute the distribution and application assembly of the invention. If it is necessary to replace entities A and D, this is easily possible by removing them each from the receiving entity R.

It should also be noted that the fluid dispensed by the dispenser D only leaves the dispenser at the level of the application surface S, so that there can be no fluid remaining inside the receiving entity R, once the dispenser has been removed. In addition, because the application surface S is perfectly continuous and smooth, it can be easily cleaned by rubbing or wiping. Thus, when a user wants to change the dispenser, it suffices beforehand to clean the application surface S, then to remove the dispenser and replace it with another. No contamination or deposition of fluid can be observed.

In the embodiment used to illustrate the present invention, the wave generation module 3 forms an application surface sector 31. This is only a particular non-limiting embodiment, since it is quite conceivable to produce the wave generation module 3 without it forming part of the application surface S. The module 3 can for example be associated with the application head 2 just below the application surface S, which will then serve as diffusion means for the waves.

The complete independence between the distributor D and the application entity A, apart from the assembly in the housing 22, makes it possible to completely dissociate these two entities, so that they can be produced by companies quite different, namely a company specializing in the design of distributors and a company specializing in the design of electronic wave generator modules.

According to the invention, this distribution assembly is further provided with means for giving an indication or visual and / or audible information to the user of the assembly as to the filling / emptying state of the reservoir 4. This information can be given on the distribution set or can even be communicated remotely to a Smartphone or a computer equipped with a dedicated application or software. In this particular assembly, the follower piston 42 is provided with a magnet M, preferably a permanent magnet, which is secured to the piston by engagement, snap-on, force insertion, overmolding, etc. On the figures 1, 2 and 6 , we can see that the magnet M is arranged in a housing 43 formed by the piston 42. The magnet M is in the form of a grain or a small stud, for example of cylindrical shape, having a diameter of the order of 2 to 5 mm and a height / thickness of the order of 2 to 4 mm. A volume of 10 mm3 to 50 mm3 is possible, with a preference, in order, for 40 mm3, 30 mm3 and 20 mm3. It would be advantageous if the attraction force of the magnet M is low enough that the follower pistons 42 do not adhere to each other, in order to facilitate their handling in the assembly lines.

The follower piston 42 is caused to move over a maximum stroke whose low initial position is shown on the figures 1 and 6 and a high end position which is represented on the figure 2 . It can also be said that the piston 42 slides between a starting position corresponding to a substantially full state of the tank and an arriving position corresponding to a substantially empty state of the tank.

Still according to the invention, the module 3 is provided with detection means comprising a magnetic field sensor 35 capable of detecting remotely, in a restricted detection field, the magnetic field generated by the magnet M when it enters this restricted detection field. The sensitivity of the sensor can for example be of the order of 7 Gauss. The magnetic field sensor 35 is disposed in the direct or immediate proximity, or even in contact, of the external wall of the sliding barrel 41 of the reservoir, so as to reduce the distance between the sensor 35 and the magnet M. The sensor magnetic field 35 is positioned axially of the upper end position of the follower piston 42, so that the magnet M enters the restricted detection field when the follower piston 42 reaches an alert position which is close to the final position high. This alert position is preferably closer to the position final high only from the initial low position. It is also possible to provide several alert positions, for example when the piston 42 is at mid-stroke, ¾ of its stroke, 90% of its stroke and / or 100% of its stroke. An alert position at ¼ of its course is also possible.

The detection means also comprise alert means, coupled to the magnetic field sensor 35, for delivering an alert signal visually or audibly perceptible. In the case of the distribution set of Figures 1 to 8 , these alert means are in the form of a light source 36, for example of the LED type, visible through a window 16 of the body 1. An audible warning can also be envisaged, in replacement or in addition to the light source 36.

According to a practical aspect, the magnetic field sensor 35 and the light source 36 can be mounted on a printed circuit board 37 of the module 3. It can be noted that the integrated circuit plate extends substantially parallel to a plane passing through the fluid reservoir, the dispensing member and the dispensing orifice.

We will now refer to Figures 9 and 10 to describe a second embodiment of the invention. The set of distribution and application of the figure 9 is only shown very schematically, but we can identify a fluid reservoir R forming a sliding barrel 41 inside which is mounted a piston P biased by a spring K. Thus, the fluid stored at the interior of the reservoir R is subjected to a pressure exerted by the piston P urged by the spring K. At its opposite end, the reservoir R is connected to a distribution valve V which can be actuated by means of a pusher 15 '. Thus, the user can press this plunger 15 ′ to open the distribution valve V, so that the fluid stored under pressure in the tank R is discharged through the open valve and then through an outlet conduit 60 ′, to reach the level of an application surface 21 '. In this distribution assembly, the reservoir R can also be in the form of a cartridge which can be inserted into the distribution assembly so as to be connected to the valve. distribution V. Alternatively, the distribution valve V can be an integral part of the cartridge.

According to the invention, this distribution assembly is also equipped with a printed circuit board 37 'on which is mounted a wavelength sensor 35', which can for example detect the wavelength corresponding to red. Furthermore, according to the invention, the piston P can be made in part or in whole with a red plastic material or coated with a red coating. Thus, when the piston P reaches the restricted detection field of the sensor 35 ', advantageously located near its final position, the sensor 35' sends an alert signal to an audible warning 36 ', possibly mounted on the card. printed circuit 37 '.

Compared to the first distribution set of Figures 1 to 8 , this second distribution assembly differs in that the piston P is not a follower piston, but a pushing piston urged by a force, such as a spring, the sensor is a wavelength sensor, and not not a magnetic field sensor, and the warning setpoint is audible, rather than visual.

The piston P is also shown on the figure 10 enlarged. One can for example imagine that the outer periphery of the piston P is coated with a layer of color, for example red, detectable by the sensor 35 '.

The sensor 35 'is arranged at the end of the piston stroke, but it could also be positioned in another location. One can also imagine implementing several sensors 35 ′ at different alert positions of the piston P, in order to provide several respective and distinct alert signals. One can for example provide a short tone when the piston reaches halfway, two short tones when it reaches three quarters of the stroke and a single long tone when it reaches the end of the stroke.

Referring to the figure 11 , we see an alternative embodiment for a piston P ', which can be a follower piston or a pusher piston. Its peculiarity lies in the fact that this piston P ′ is produced with a plastic material loaded with magnetic particles. Such a piston P 'can very well be implemented in the first embodiment of Figures 1 to 8 , replacing the piston 42.

With reference to the figure 12 , we see yet another embodiment for a piston P ", which comprises a magnet M 'which is in the form of a ring or a ring. The annular magnet M' can simply be embedded in force to The inside of the piston. The advantage of an annular magnet M 'lies in the fact that the magnet is closer to the barrel 41 of the reservoir and therefore closer to the magnetic field sensor 35. As a result, a magnet lower power can be used.

It goes without saying that a wavelength sensor 35 ′ can also be implemented in the first embodiment of the Figures 1 to 8 , with the piston P. Conversely, a magnetic field sensor can be implemented in place of the sensor 35 ′ in the embodiment of the figure 9 . A piston, such as piston 42, piston P 'or piston P "can then be used in this second embodiment.

The embodiments which have just been described implement remote detection technologies using the magnetic field or the color. However, other remote detection technologies can be used, such as induction (magnetic field detection or magnetic field disturbance detection), optics (color, reflection, refraction, diffraction) , capacitive effect, ultrasound, hall effect, Faraday effect, resistance variation, etc. One can for example provide detection means in the form of a magnetic field disturbance sensor emitting a magnetic field and a piston comprising an element capable of disturbing the magnetic field generated by the magnetic field disturbance sensor. One can also envisage an optical sensor sensitive to the reflection of light produced by reflective particles or a coating carried by the piston.

Thanks to the invention, there is a distribution assembly comprising a reservoir in which a piston (follower or pusher) moves, and the filling / emptying state of which can be communicated to the user by means of remote detection.

Claims (14)

1. A fluid dispenser assembly comprising a fluid reservoir (R), a dispenser member (5; V), and a dispenser orifice (62), the fluid reservoir (R) including a piston (42; P; P'; P") that is movable in leaktight sliding contact in a slide cylinder (41) over a maximum stroke defined between a start position that corresponds to a substantially full state of the reservoir, and an end position that corresponds to a substantially empty state of the reservoir, the dispenser assembly being characterized in that it further comprises detector means (35; 35') for detecting a physical property, the detector means having a detection field that is small relative to the maximum stroke of the piston, the physical-property detector means (35; 35') being arranged outside the fluid reservoir (R) so as to act remotely, through the slide cylinder (41), to detect a determined physical property that enters into the small detection field that covers an alert position of the piston that is closer to the end position than to the start position, the piston (42; P; P'; P") carrying said detectable determined physical property, the detection means (35; 35') delivering, in response to a detection of the physical property, at least one alert signal that is perceptible to a user.
2. A dispenser assembly according to claim 1, wherein the slide cylinder (41) is arranged between the piston (42; P; P'; P") and the detector means (35; 35'), the slide cylinder (41) not preventing the detector means (35; 35') from detecting the determined physical property.
3. A dispenser assembly according to claim 1 or claim 2, wherein the alert position is reached when the piston (42; P; P'; P") has moved through more than 75%, or more than 90%, or even 100%, of its maximum stroke from the start position.
4. A dispenser assembly according to any preceding claim, wherein the piston (42; P; P'; P") reaches a plurality of successive alert positions as it moves towards the end position, the alert positions being successively detected by the detector means (35; 35'), that advantageously deliver a plurality of distinct respective alert signals.
5. A dispenser assembly according to any preceding claim, wherein the detector means (35; 35') are mounted on an integrated circuit board (37; 37').
6. A dispenser assembly according to any preceding claim, wherein the fluid reservoir (R), the dispenser member (5; V) and the dispenser orifice (62) are formed by a dispenser (D) that is removably insertable into a casing (B) forming an applicator surface (S) and integrating the detector means (35), which detector means are advantageously mounted on an integrated circuit board (37), that extends substantially parallel to a plane that contains the fluid reservoir (R), the dispenser member (5; V) and the dispenser orifice (62).
7. A dispenser assembly according to any preceding claim, wherein the detector means (35; 35') are positioned in contact with the slide cylinder (41), or in its immediate proximity, so as to reduce the distance between them and the piston (42; P; P'; P").
8. A dispenser assembly according to any preceding claim, wherein the detector means (35; 35') comprise a magnetic-field sensor (35) and the piston (42; P'; P") is provided with a magnet (M; M') that generates a magnetic field as the detectable determined physical property.
9. A dispenser assembly according to claim 8, wherein the magnet (M) presents a volume that is less than 40 mm³, advantageously less than 30 mm³, and still more advantageously less than 20 mm³.
10. A dispenser assembly according to claim 8 or claim 9, wherein the magnet (M') is annular with an outside diameter that is a little smaller than the maximum outside diameter of the piston (42; P'; P"), such that the magnet (M') is close to the slide cylinder.
11. A dispenser assembly according to any one of claims 1 to 7, wherein the detector means comprise a magnetic-field sensor (35), and the piston (P') is made by injection-molding plastics material filled with magnetized particles.
12. A dispenser assembly according to any one of claims 1 to 7, wherein the detector means comprise a determined-wavelength sensor (35'), and the piston (P) absorbs waves having said determined wavelength, the determined wavelength is advantageously in the red and the piston (P) is red at least in part.
13. A dispenser assembly, wherein according to any one of claims 1 to 7, the detector means comprise a magnetic-field-disruption sensor that emits a magnetic field, and the piston includes an element that is capable of disrupting the magnetic field generated by the magnetic-field-disruption sensor.
14. A dispenser assembly according to any preceding claim, wherein the piston (42; P; P'; P") is a follower piston that moves when the fluid in the reservoir (R) is under suction.

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