EP3569319A1 - Piston for tank of a fluid product dispenser with no air intake - Google Patents

Abstract

Piston 1 for reservoir 10 of a distributor of a fluid product without air intake, having a central axis X and comprising: - sealing means 2; - guiding means 3.This piston is characterized in that said sealing means 2 extend in a plane orthogonal to the axis X and define a single external sealing line in a closed loop, distal from the axis X, able to come into contact with an inner wall 14 of the reservoir 10, and in that said guide means 3 comprise a base 8 of which extend a plurality of tabs 4 having free ends 6 defining outer guide points, distal to the axis X, able to come into contact of the inner wall 14 of the tank 10.

Description

Field of the invention

The invention relates to a piston for a reservoir of a dispenser of a fluid product without air intake. The invention also relates to a fluid dispenser without air intake comprising a reservoir adapted to store the fluid and housing such a piston.

The fluid product is of the lotion, gel, perfume or cream type, for example, used for cosmetic purposes or for pharmaceutical treatments.

State of the art

Distributors without air intake, so-called "airless" (lack of air in the tank), are provided with pistons called "followers". They are in contact with the product and go back to each distribution under the effect of the depression in the reservoir induced by this distribution.

These pistons generally comprise two sealing lips pressed against the side wall of the reservoir spaced axially from each other to further ensure a function of guiding the piston in its race in the tank. Indeed, it must remain oriented so that the piston / wall sealing line remains in a plane substantially orthogonal to the direction of movement of the piston. The lips exert a flat support against the inner wall of the tank, each forming an unsightly sealing ring having a height, corresponding to the height of the lip, and clearly visible from the outside of the tank.

The volume between the two lips is made of air and makes perfectly visible the lateral surface of the piston which extends between these two lips when the walls of the tank are transparent or translucent.

The reservoir is preferably made of plastic, for example PETG (glycolized polyethylene terephthalate). The tank can also be made of glass. In this case, the dimensional tolerance is more difficult to respect. A stretched glass process is then preferred for questions of respect of dimensional tolerances.

The piston is a visible and unsightly mechanical element, perceived as trivially functional, and does not correspond to the image of some prestigious brands of cosmetics. The object of the present invention is to eliminate or at least mitigate this effect.

The problem to be solved is to hide the piston, to make it invisible or to make it a movable aesthetic element, within the tank.

Summary of the invention

• des moyens d'étanchéité ;
• des moyens de guidage.

The present invention aims to overcome the various disadvantages mentioned above, by means of a piston for a reservoir of a fluid dispenser without air intake, having a central axis X and conventionally comprising:

• sealing means;
• guiding means.

This piston is characterized in principal in that said sealing means extend in a plane orthogonal to the X axis and define a single outer sealing line in a closed loop, distal to the X axis, suitable for coming in contact with an inner wall of the tank, and in that said guiding means comprise a base from which extend a plurality of tabs having free ends defining outer guide points, distal to the X axis, adapted to come into contact with the inner wall of the tank.

The main idea of this invention is to provide a piston which has a minimum contact area with the inner wall of the tank.

The lateral ends of the piston are composed solely of the outer sealing line, and outer guide points. Only these lateral ends will be in contact with the tank, and will therefore be visible from the outside by the distributor's user. In the end, there will be only a single line of contact and points of contact that will be visible to the user through the tank.

Indeed, the existence of the legs for guiding the piston allows the fluid to be inserted between the legs and all around the base, so as to camouflage the piston. There is therefore no more air volume between two lips as was the case in the prior art, where the piston body was then clearly visible.

The piston of the present invention no longer forms an unsightly sealing ring visible from the outside of a tank. In the claimed piston, the sealing means define a single outer sealing line. This unique line is thus very discreet compared to the two crowns of the prior art.

In the same way, the outer guide points are very discreet, and hardly visible by the user through the tank.

• lesdits moyens d'étanchéité se développent autour de ladite base.
• le piston présente au moins trois pattes : cela permet d'éviter un basculement du piston dans le réservoir.
• les moyens de guidage sont principalement conçus dans un matériau rigide du type PP ou PCTA ou PET, tandis que les moyens d'étanchéité sont conçus dans un matériau souple du type SEBS, ou PE très basse densité, ou polyuréthane : les moyens d'étanchéité doivent pouvoir s'écraser contre la paroi intérieure du réservoir, afin de former une étanchéité et que le produit fluide contenu dans le réservoir ne puisse pas contourner le piston.
• les extrémités libres des moyens de guidage sont conçues dans un matériau souple du type PE ou PTFE : cela permet aux pattes d'absorber les dispersions dimensionnelles radiales de la paroi intérieure du réservoir contre laquelle elles sont en contact. Dans ce cas, les tolérances dimensionnelles radiales des réservoirs peuvent être moins drastiques. Il en est de même pour les tolérances dimensionnelles radiales des pistons.
• le piston peut consister en une seule pièce obtenue par injection d'une ou plusieurs matières : il peut s'agir d'une pièce mono-injectée, ou bi-injectée, ou tri-injectée par exemple.
• le piston peut consister en une pluralité de pièces assemblées par exemple par collage ou encliquetage ou par montage en force.
• l'extrémité libre des pattes présente une forme arrondie : cette forme permet d'assurer un contact seulement quasi-ponctuel avec la paroi intérieure du réservoir, et de favoriser le glissement.
• l'extrémité libre des pattes présente une zone de glisse : cette zone de glisse correspond à une petite surface, du type patin, qui permet d'assurer un contact ponctuel légèrement plus important que dans la version précédente avec la forme arrondie, avec la paroi intérieure du réservoir. Cette zone de glisse permet d'améliorer le glissement du piston dans le réservoir, mais le point de contact entre le piston et le réservoir est un peu plus grand. Le piston perd en invisibilité ce qu'il gagne en guidage.
• les extrémités libres des pattes sont réparties de façon homogène, à équidistance les unes des autres : elles permettent un appui homogène sur tout le pourtour de la paroi intérieure du réservoir.
• les extrémités libres des pattes sont toutes contenues dans un même plan P orthogonal à l'axe X et à distance des moyens d'étanchéité : les pattes permettent d'assurer un positionnement parfaitement horizontal du piston au sein du réservoir. Elles sont suffisamment éloignées des moyens d'étanchéité, de façon à ce que les points de contact avec le réservoir soient à distance de la ligne de contact, pour assurer un guidage optimal du piston dans le réservoir sans risque de basculement du piston.
• le piston comporte des propriétés microbiocides : plus précisément, le piston est réalisé à base d'au moins un matériau présentant des propriétés microbiocides par diffusion d'un agent antimicrobien, par contact avec un agent microbiostatique et/ou par irradiation avec un rayonnement de longueur d'onde adaptée.
• les moyens d'étanchéité consistent en un boudin souple s'étendant autour de la base du piston.
• les moyens d'étanchéité consistent en un joint torique, s'insérant dans une rainure prévue à cet effet dans la base du piston.
• les moyens d'étanchéité consistent en une lèvre souple : dans ce cas, la lèvre sera dimensionnée de manière à ce que seule une petite zone entre en contact avec les parois intérieures du flacon, de manière à former une ligne extérieure d'étanchéité, et non pas une couronne extérieure d'étanchéité.
• les moyens d'étanchéité consistent en un disque souple dont le pourtour est recourbé dans une direction opposée aux pattes, ledit pourtour formant une lèvre d'étanchéité.
• ladite base comporte une partie centrale pleine, montée sur ledit disque, la base et le disque présentant chacun une partie centrale d'allure concave, la partie centrale dudit disque suivant le profil de la partie centrale de la base.
• ladite base correspondant à une couronne définissant un évidement central, le disque présentant une partie centrale d'allure convexe pénétrant à l'intérieur de l'évidement central de la base.
• la partie centrale d'allure convexe du disque est apte à s'inverser pour prendre une allure concave.
• le piston présente des côtés latéraux rectilignes reliés deux à deux par des arrondis : le piston peut être par exemple de forme carronde, ou triangulaire, ou autre.
• le piston présente une forme circulaire.

According to the different embodiments of the invention, which can be taken together or separately:

• said sealing means develop around said base.
• the piston has at least three legs: this avoids tilting of the piston in the tank.
• the guiding means are mainly designed in a rigid material of the PP or PCTA or PET type, while the sealing means are made of a flexible material of the SEBS type, or very low density PE, or polyurethane: the sealing means must be able to crash against the inner wall of the tank, to form a seal and that the fluid contained in the tank can not bypass the piston.
• the free ends of the guide means are designed in a flexible material of the PE or PTFE type: this allows the tabs to absorb the radial dimensional dispersions of the inner wall of the tank against which they are in contact. In this case, the radial dimensional tolerances of the tanks may be less drastic. It is the same for the radial dimensional tolerances of the pistons.
• the piston may consist of a single piece obtained by injection of one or more materials: it may be a mono-injected part, or bi-injected, or tri-injected for example.
• the piston may consist of a plurality of parts assembled for example by gluing or latching or by force fitting.
• the free end of the legs has a rounded shape: this form ensures a contact only quasi-punctual with the inner wall of the tank, and promote sliding.
• the free end of the legs has a gliding zone: this gliding zone corresponds to a small surface, of the skid type, which makes it possible to ensure a slightly greater point contact than in the previous version with the shape rounded, with the inner wall of the tank. This sliding zone improves the sliding of the piston in the tank, but the point of contact between the piston and the tank is a little larger. The piston loses in invisibility what it gains in guiding.
• the free ends of the legs are distributed homogeneously, equidistant from each other: they allow a homogeneous support all around the inner wall of the tank.
• the free ends of the tabs are all contained in the same plane P orthogonal to the X axis and remote sealing means: the tabs ensure a perfectly horizontal positioning of the piston within the reservoir. They are sufficiently far from the sealing means, so that the contact points with the tank are away from the contact line, to ensure optimal guidance of the piston in the tank without risk of tilting of the piston.
• the piston comprises microbiocidal properties: more specifically, the piston is made of at least one material having microbiocidal properties by diffusion of an antimicrobial agent, by contact with a microbiostatic agent and / or by irradiation with a radiation of length adapted waveform.
• the sealing means consist of a flexible bead extending around the base of the piston.
• the sealing means consist of an O-ring, inserted in a groove provided for this purpose in the base of the piston.
• the sealing means consist of a flexible lip: in this case, the lip will be dimensioned so that only a small area comes into contact with the inner walls of the bottle, so as to form an outer sealing line, and not an outer sealing ring.
• the sealing means consist of a flexible disc whose periphery is curved in a direction opposite to the tabs, said periphery forming a sealing lip.
• said base comprises a solid central portion mounted on said disk, the base and the disk each having a concave central portion, the central portion of said disk following the profile of the central portion of the base.
• said base corresponding to a crown defining a central recess, the disc having a convex central portion penetrating inside the central recess of the base.
• the convex central portion of the disc is able to reverse to take a concave pace.
• the piston has rectilinear lateral sides connected in pairs by roundings: the piston may be for example of square shape, or triangular, or other.
• the piston has a circular shape.

The invention also relates to a fluid dispenser without air intake comprising a reservoir adapted to store the fluid and housing a piston as described above, the reservoir having a bottom and a collar located opposite the bottom, said piston sealing means being in contact with an inner wall of the tank forming a nip, and the free ends of the tabs being in contact with the inner wall of the tank forming contact points.

• le piston se déplace dans le réservoir entre une position inférieure proximale du fond du réservoir et une position supérieure proximale du col du réservoir, le distributeur présentant une forme complémentaire au piston au voisinage du col du réservoir : cette forme complémentaire loge la partie supérieure du piston et limite ainsi le volume mort entre la partie supérieure du piston et le haut du réservoir où se trouve encore du produit fluide alors que le piston est en butée de fin de course. Le taux de restitution du produit fluide est ainsi amélioré.
• ladite forme complémentaire est réalisée dans le col même du réservoir : le réservoir en lui-même présente la forme femelle complémentaire des moyens de guidage du piston.
• ladite forme complémentaire est réalisée dans une bague montée sur ou dans le col du réservoir : par exemple, la bague pénètre dans le col du réservoir, et le piston vient alors s'emboîter dans la bague.
• ladite forme complémentaire présente des rampes de guidage et d'indexage radial des pattes : notamment lorsque le réservoir présente une paroi intérieure cylindrique, il est possible que le piston ne soit initialement pas positionné de manière à ce que les pattes soient en vis-à-vis des formes femelles où elles sont censées se loger au sein de la forme complémentaire en fin de course du piston, ou il est possible que le piston tourne légèrement lorsqu'il remonte le long du réservoir entraînant un désalignement des pattes par rapport aux formes femelles. Il faut donc guider chaque patte vers sa forme femelle respective. Des parois inclinées en forme de V sont donc prévues entre les formes femelles adjacentes, afin de guider chaque patte vers l'une des formes femelles, puis d'indexer angulairement les pattes par rapport aux formes femelles, et que le piston s'insère finalement correctement dans la forme complémentaire générale. Concrètement, les pattes glissent le long des rampes, conduisant à une rotation du piston lors de son déplacement axial de fin de course, induisant un auto-alignement des moyens de guidage du piston avec la forme complémentaire. Les moyens de guidage sont ainsi eux-mêmes guidés.
• les pattes sont escamotables au contact avec le col du réservoir ou avec une bague montée sur le col du réservoir : les pattes peuvent être souples et se déformer, ou être repliables par exemple. Dans ce cas, il n'est pas nécessaire de prévoir une forme complémentaire en partie supérieure du réservoir, que ce soit dans le col ou dans la bague. Avec cette technique, il est possible de conserver une extension axiale suffisante des pattes par rapport aux moyens d'étanchéité pour assurer un guidage efficace. L'avantage des pattes escamotables est que la course du piston est plus importante qu'avec des pattes indéformables car il n'y a pas d'espace perdu par une forme complémentaire, et ainsi la surface du réservoir disponible au cosméticien pour affichage (nom de produit, etc...) est augmentée.
• le piston est composé d'un matériau présentant un indice de réfraction allant de 1,36 à 1,44: il s'agit d'un matériau transparent, utilisé notamment lorsque le produit fluide est transparent, tel que le parfum qui est composé essentiellement de cétones et d'alcools. Le piston est ainsi « invisible » dans le parfum.
• le piston est conçu dans un matériau contenant du fluor.
• le piston est revêtu d'une décoration, du type film, apposée sur au moins une partie de sa surface extérieure, excepté sur sa ligne d'étanchéité : si la décoration est d'une couleur différente de celle du produit fluide, alors le piston est visible mais devient un élément de décoration mobile dans le réservoir et n'est plus associé à un élément mécanique. Si la décoration est d'une couleur ajustée à celle du produit fluide, lorsque ce dernier est transparent et de couleur, alors le piston est toujours « invisible ». Par exemple, le piston peut être décoré sur l'ensemble de sa surface extérieure, excepté sur sa ligne d'étanchéité, par un film décoratif.
• le piston est conçu dans un matériau coloré intrinsèquement : lorsque le produit fluide est transparent et de couleur, le piston peut être d'une couleur ajustée à la couleur du produit fluide, par l'utilisation d'un matériau permettant cette coloration.
• les pattes du piston sont orientées vers le col du réservoir : dans ce cas, les pattes sont immergées dans le produit fluide.
• les pattes du piston sont orientées vers le fond du réservoir : dans ce cas, les pattes ne viendront pas en butée de fin de course contre la partie supérieure du réservoir. Seule la surface de la base orientée vers le col du réservoir viendra en butée de fin de course. Dans ce cas, les pattes se situent sous les moyens d'étanchéité, et ne sont pas en contact avec le produit fluide, et sont donc bien visibles. De préférence, le piston sera dans ce cas décoré.
• les moyens d'étanchéité consistent en un boudin souple s'étendant autour de la base du piston, et épousant la forme intérieure du réservoir : le boudin peut être de formée carrée, ronde, carronde, triangulaire, etc.
• les moyens d'étanchéité du piston comprennent une lèvre d'étanchéité, le fond du réservoir présentant une gorge périphérique dans laquelle se loge ladite lèvre d'étanchéité.

According to the different embodiments of the invention, which can be taken together or separately:

• the piston moves in the reservoir between a lower proximal position of the bottom of the reservoir and a proximal upper position of the neck of the reservoir, the dispenser having a shape complementary to the piston in the vicinity of the neck of the reservoir: this complementary shape houses the upper part of the piston and thus limits the dead volume between the upper part of the piston and the top of the tank where there is still fluid while the piston is in limit stop. The rate of return of the fluid product is thus improved.
• said complementary shape is formed in the same neck of the tank: the tank itself has the complementary female shape of the piston guiding means.
• said complementary shape is formed in a ring mounted on or in the neck of the reservoir: for example, the ring penetrates into the neck of the reservoir, and the piston then engages in the ring.
• said complementary shape has ramps for guiding and indexing radial tabs: especially when the reservoir has a cylindrical inner wall, it is possible that the piston is initially not positioned so that the legs are vis-à- screw female shapes where they are expected to be housed within the complementary shape at the end of the stroke of the piston, or it is possible that the piston rotates slightly as it rises along the tank resulting in misalignment of the legs relative to the female forms . It is therefore necessary to guide each leg to its respective female form. V-shaped inclined walls are therefore provided between the adjacent females, in order to guide each tab to one of the female shapes, and then to angularly index the tabs with respect to the female shapes, and that the piston is finally inserted. correctly in the general complementary form. Specifically, the tabs slide along the ramps, leading to a rotation of the piston during its axial displacement end of stroke, inducing a self-alignment of the piston guide means with the complementary shape. The guide means are themselves guided.
• the legs are retractable in contact with the neck of the tank or with a ring mounted on the neck of the tank: the legs can be flexible and deformed, or be foldable for example. In this case, it is not necessary to provide a complementary shape in the upper part of the tank, whether in the neck or in the ring. With this technique, it is possible to maintain sufficient axial extension of the tabs relative to the sealing means to ensure effective guidance. The advantage of the retractable legs is that the stroke of the piston is greater than with non-deformable legs because there is no space lost by a complementary shape, and thus the tank surface available to the cosmetologist for display (name of product, etc ...) is increased.
• the piston is composed of a material having a refractive index ranging from 1.36 to 1.44: it is a transparent material, used in particular when the fluid product is transparent, such as the perfume which is composed essentially ketones and alcohols. The piston is thus "invisible" in the perfume.
• the piston is made of a material containing fluorine.
• the piston is coated with a decoration, of the film type, affixed to at least a part of its outer surface, except on its sealing line: if the decoration is of a color different from that of the fluid product, then the piston is visible but becomes a mobile decorative element in the tank and is no longer associated with a mechanical element. If the decoration is of a color adjusted to that of the fluid product, when the latter is transparent and colored, then the piston is always "invisible". For example, the piston may be decorated on its entire outer surface, except on its sealing line, with a decorative film.
• the piston is designed in an inherently colored material: when the fluid product is transparent and colored, the piston may be of a color adjusted to the color of the fluid, by the use of a material allowing this coloring.
• the legs of the piston are oriented towards the neck of the tank: in this case, the legs are immersed in the fluid.
• the legs of the piston are oriented towards the bottom of the tank: in this case, the tabs will not come into limit stop against the upper part of the tank. Only the surface of the base facing the neck of the tank will come to the end stop. In this case, the tabs are located under the sealing means, and are not in contact with the fluid, and are therefore clearly visible. Preferably, the piston will be decorated in this case.
• the sealing means consist of a flexible bead extending around the base of the piston, and matching the inner shape of the tank: the bead can be of square, round, square, triangular, etc.
• the sealing means of the piston comprise a sealing lip, the bottom of the tank having a peripheral groove in which is housed said sealing lip.

Presentation of figures

The invention will be better understood, and other objects, details, features and advantages thereof will become more clearly apparent in the following detailed explanatory description of at least one embodiment of the invention given to As a purely illustrative and non-limiting example, with reference to the accompanying schematic drawings.

• les figures 1a à 1d représentent un piston selon un premier mode de réalisation de l'invention ;
• les figures 2a et 2b représentent un piston selon un second mode de réalisation de l'invention ;
• les figures 3a et 3b représentent un piston selon un troisième mode de réalisation de l'invention ;
• les figures 4a à 4c représentent un réservoir comportant une forme complémentaire apte à recevoir un piston selon le premier, le second et le troisième mode de réalisation de l'invention ;
• la figure 4d représente le piston dans sa position initiale au fond du réservoir tel qu'illustré aux figures 4a à 4c ;
• la figure 4e représente le piston dans sa position finale en haut du réservoir tel qu'illustré aux figures 4a à 4c ;
• les figures 5a et 5d représentent un piston et sa forme complémentaire selon un quatrième mode de réalisation de l'invention ;
• les figures 6a et 6b représentent le piston et sa forme complémentaire selon un cinquième mode de réalisation de l'invention ;
• la figure 7 représente le piston selon un sixième mode de réalisation de l'invention ;
• la figure 8 représente le piston selon un septième mode de réalisation de l'invention ;
• la figure 9 représente le piston selon un huitième mode de réalisation de l'invention ;
• les figures 10a à 10b représentent le piston selon un neuvième mode de réalisation de l'invention ;
• les figures 11 a à 11 e représentent le piston selon un dixième mode de réalisation de l'invention ;
• les figures 12a à 12b représentent le piston selon un onzième mode de réalisation de l'invention ;
• les figures 13a à 13c représentent le piston et son intégration au sein d'un réservoir selon un douzième mode de réalisation de l'invention ;
• les figures 14a à 14c représentent le piston et son intégration au sein d'un réservoir selon un treizième mode de réalisation de l'invention.

On these drawings:

• the Figures 1a to 1d represent a piston according to a first embodiment of the invention;
• the Figures 2a and 2b represent a piston according to a second embodiment of the invention;
• the Figures 3a and 3b represent a piston according to a third embodiment of the invention;
• the Figures 4a to 4c represent a reservoir having a complementary shape adapted to receive a piston according to the first, the second and the third embodiment of the invention;
• the figure 4d represents the piston in its initial position at the bottom of the tank as illustrated in Figures 4a to 4c ;
• the figure 4e represents the piston in its final position at the top of the tank as illustrated in Figures 4a to 4c ;
• the Figures 5a and 5d represent a piston and its complementary shape according to a fourth embodiment of the invention;
• the Figures 6a and 6b represent the piston and its complementary shape according to a fifth embodiment of the invention;
• the figure 7 represents the piston according to a sixth embodiment of the invention;
• the figure 8 represents the piston according to a seventh embodiment of the invention;
• the figure 9 represents the piston according to an eighth embodiment of the invention;
• the Figures 10a to 10b represent the piston according to a ninth embodiment of the invention;
• the figures 11 a to 11 e represent the piston according to a tenth embodiment of the invention;
• the Figures 12a to 12b represent the piston according to an eleventh embodiment of the invention;
• the Figures 13a to 13c represent the piston and its integration within a reservoir according to a twelfth embodiment of the invention;
• the Figures 14a to 14c represent the piston and its integration within a reservoir according to a thirteenth embodiment of the invention.

detailed description

In the remainder of the description, elements having an identical structure or similar functions are designated by the same references.

Distributors without air intake, called "airless" (lack of air in the tank 10), are provided with pistons called "followers". They are in contact with the product and go back to each distribution under the effect of the depression in the reservoir induced by this distribution. Several embodiments of such pistons according to the invention will be described below.

With reference to all the figures, the piston 1 is composed in particular of sealing means 2 and guiding means 3. These sealing means 2 and these guiding means 3 have ends which define an outer casing of the piston 1, adapted to coincide with the internal volume of a tank 10 in which the piston 1 is introduced.

In particular, if the inner wall 14 of the tank 10 is of cylindrical shape, then the outer casing of the piston 1 will also be cylindrical.

Similarly, if the inner wall 14 of the tank 10 defines a square or rectangular or triangular cross section, then the sealing means 2 of the piston 1 will define a square or rectangular or triangular cross section and the guide means 3 also, so that the piston 1 fits perfectly within the reservoir 10 and comes into contact with the inner side walls 14 of the reservoir 10.

The sealing means 2 of the piston 1 make it possible to divide the reservoir 10 into two sealed zones with respect to one another. In particular, when the reservoir 10 contains fluid, the sealing means 2 allow the fluid contained in a first zone, for example above the piston 1, not to bypass the piston 1 and not to reach the second zone located in this case below the piston 1.

The guide means 3 of the piston 1 make it possible to keep the piston 1 in a stable position transversely inside the tank 10, and allow the piston 1 to move axially inside the tank 10 while remaining in stable positions at the interior of the tank 10 over its entire travel path.

The Figures 1a to 1d illustrate a first embodiment of the piston 1 according to the invention.

In this first mode, the piston 1 has a square shape, that is to say square with the four rounded corners.

• une patte 4 s'étend au centre de la face ;
• une patte 4 s'étend en périphérie de la face et en direction d'un coin arrondi adjacent, par exemple cette patte 4 s'étend sur la gauche de la face et en direction du coin gauche ;
• une patte 4 s'étend en périphérie de la face en direction d'un autre coin arrondi adjacent, par exemple cette patte 4 s'étend sur la droite de la face et en direction du coin droit.

This piston 1 comprises a base 8 of which extend twelve guide lugs 4 each terminated by a free end 6 of rounded shape. The base 8 has four faces, three legs 4 extending from each face. On each side:

• a leg 4 extends to the center of the face;
• a tab 4 extends on the periphery of the face and towards an adjacent rounded corner, for example this tab 4 extends to the left of the face and towards the left corner;
• a tab 4 extends on the periphery of the face towards another adjacent rounded corner, for example this tab 4 extends to the right of the face and towards the right corner.

The rounded shapes of all the legs 4 are located at the same plane, that is to say at the same height relative to the base 8.

Each face therefore has the same number of legs 4, with the same orientations, and with the same shapes.

The more legs 4, the less the risk of tilting of the piston 1 in the tank 10 exists.

The base 8 and the lugs 4 form what are called the guide means 3 of the piston 1.

Around the base 8 extends an annular flange which forms what are called the sealing means 2 of the piston 1.

The piston 1 comprises a central axis X as defined on the figure 1d . The tabs 4 develop around this axis X and lie in the same plane P transverse to this axis X.

When the piston 1 is inserted inside a reservoir 10, as is for example illustrated on the figure 4d , it is clearly visible that the bead is in contact with the inner side walls of the tank 10, and the rounded shapes 6 of the lugs 4 are also in contact with the inner side walls of the tank 10.

The flange has a curved periphery so as to form only one outer line of contact with the reservoir 10. This line is very discrete when the piston 1 is observed through the transparent or translucent reservoir 10.

The rounded shapes 6 of the tabs 4 in turn each form a point contact with the inner walls 14 of the tank 10. These point contacts consist of points larger or smaller depending on the shape of the rounded part, and which are therefore also very discreet visually from the outside of the tank 10.

The larger the diameter of the rounded part, the bigger the point of contact will be. Conversely, the smaller the diameter of the rounded portion, the smaller the point of contact will be. It is also possible to envisage small surfaces of the pad type at the ends of the legs 4. The contact point will be a little larger, but the piston 1 will be better guided.

Finally, when the piston 1 is inserted within the tank 10, the user will see only one outer line and a plurality of points, in this case 3 per face, through the wall of the tank 10.

The tabs 4 extend sufficiently far from the sealing means 2 in order to ensure better stability in the movement of the piston 1 within the reservoir 10 and to avoid any risk of tilting of the piston 1.

• H = distance axiale entre un point de contact de guidage et un point de contact d'étanchéité situé juste en-dessous.
• Φ = plus grande dimension des moyens d'étanchéité 2.
• L = longueur transversale d'une patte 4 entre son extrémité rattachée à la base 8 et son extrémité libre 6.
• D = distance entre les extrémités libres 6 de deux pattes 4 adjacentes.

More precisely, here are the dimensional parameters, as illustrated in Figure 1c and 1d :

• H = axial distance between a guiding contact point and a sealing contact point located just below.
• Φ = greater dimension of the sealing means 2.
• L = transverse length of a tab 4 between its end attached to the base 8 and its free end 6.
• D = distance between the free ends 6 of two adjacent legs 4.

Preferably, H / Φ> 1/4: this makes it possible to obtain good guidance.

• pour un produit très opaque, on peut envisager une faible épaisseur (e = ou < à 1 mm)
• pour un produit plus translucide on choisira une épaisseur 1 < e < 3 mm

The parameter L conditions the thickness e of fluid product hiding the piston 1:

• for a very opaque product, we can consider a small thickness (e = or <1 mm)
• for a more translucent product choose a thickness 1 <e <3 mm

A greater thickness would result in a volume of product impossible to restore at the end of use of the dispenser, as illustrated in FIG. figure 4e and explained below.

The lugs 4 must ensure the upper guidance of the piston 1 by point supports, replacing a conventional continuous lip.

• aux tolérances de fabrication ;
• à la variation de diamètre entre le bas du réservoir et le haut du réservoir due à la dépouille du réservoir.

The length of the tabs 4 from the point of contact 6 to the base conditions their flexibility to absorb the dimensional variations due:

• manufacturing tolerances;
• the variation in diameter between the bottom of the tank and the top of the tank due to the draft of the tank.

• suffisamment importante pour donner l'élasticité nécessaire à l'absorption des variations dimensionnelles ;
• suffisamment courte pour assurer un minima de rigidité et assurer la fonction de guidage et éviter le basculement du piston 1.

The length L of the legs 4 must be:

• large enough to give the elasticity necessary for the absorption of dimensional variations;
• short enough to provide a minimum of rigidity and ensure the guiding function and prevent the tilting of the piston 1.

This is a compromise.

• Φ est compris entre 20 et 30mm. Dans ce mode, Φ=23.8mm.
• H est compris entre 6mm et 9mm. Dans ce mode H= 7.25mm.
• D est compris entre 5mm et 10mm. Dans ce mode, D= 7mm.
• L est compris entre 2.5mm et 4mm. Dans ce mode, L= 3.15mm.

For example :

• Φ is between 20 and 30mm. In this mode, Φ = 23.8mm.
• H is between 6mm and 9mm. In this mode H = 7.25mm.
• D is between 5mm and 10mm. In this mode, D = 7mm.
• L is between 2.5mm and 4mm. In this mode, L = 3.15mm.

In this mode, the volume of non-returnable product located between the base 8 and the inner wall 14 of the reservoir 10 is preferably less than 3 ml, more preferably less than 2 ml. In this mode, this volume is 2ml.

In the case of figure 4d , the piston 1 is located in the bottom 12 of the tank 10, in the initial position. When fluid product and poured inside the tank 10, this product is placed above the piston 1 and is inserted between the legs 4, so as to camouflage.

As the product is dispensed from this tank 10, by means of dispensing means comprising for example a pump and a push button mounted on the tank, all forming a distributor, the piston 1 goes up along the tank 10 until reaching the upper stop towards the upper end of the tank 10, corresponding to a neck 13, which is opposite to the bottom 12 of the tank 10, as illustrated in FIG. figure 4e .

To prevent there being a large dead volume between the guide means 3 of the piston 1 and the upper end 13 of the reservoir 10, that is to say a large dead volume in which there is still fluid and which can no longer be dispensed since the piston 1 is already in limit stop, it is expected to equip the piston 1 with a shape 5 to fill the dead volume and whose upper surface is in the plane P in which is all the rounded parts 6 of the legs 4.

In the first embodiment of the invention, this form 5 consists of a cube 5 extending axially between the legs 4. The upper surface of the cube 5 at the same axial position as the ends of the legs 4. The cube 5 comes to the contact with the upper end 13 of the reservoir 10. This cube 5 is therefore intended to improve the rate of return of the fluid product by decreasing the dead volume, that is to say by preventing the product stored between the legs 4 is impossible to distribute when the piston 1 is in the upper position that is to say at the end of the race.

However, there will always be a ring of thickness L (as explained above) located under the tabs 4 which can not be restored despite the complementary shape 11 of the upper end 13.

The piston 1 is made by bi-injection.

• une partie rigide composée des pattes 4, du cube 5 et de la base 8, qui est réalisé dans un matériau rigide du type PP (polypropylène), qui est un matériau allant du blanc au translucide et convient bien pour cet usage de piston discret lorsque la formule cosmétique à l'intérieur du réservoir est opaque. Par contre, pour des formules translucides, on préférera le PCTA (Polycyclohéxylène diméthylène téréphtalate modifié acide), qui est un polymère ultra transparent, présentant l'aspect d'un cristal. À titre d'alternative, on peut également considérer pour la partie rigide l'utilisation d'un PET (polyéthylène téréphtalate) ou un PETG (polyéthylène téréphtalate glycolysé), également transparent. De plus, l'avantage du PCTA sur les autres polymères transparents, telles que le PMMA, est une meilleure compatibilité chimique avec les formules cosmétiques contenues à l'intérieur du réservoir..
• une partie souple composée du boudin d'étanchéité qui est réalisée en SEBS (polystyrène-b-poly(éthylène-butylène)-b-polystyrène) ou bien en polyéthylène très basse densité, ou encore en polyuréthane. Il est également possible de réaliser la partie souple en TPE (élastomère thermoplastique). La partie souple est surmoulée sur la partie rigide.

In this case, the piston 1 comprises:

• a rigid part composed of tabs 4, cube 5 and base 8, which is made of a rigid material of the PP (polypropylene) type, which is a material ranging from white to translucent and is well suited for this discrete piston use when the cosmetic formula inside the tank is opaque. On the other hand, for translucent formulations, PCTA (polycyclohexylene dimethylene terephthalate modified with acid), which is an ultra transparent polymer having the appearance of a crystal, is preferred. As an alternative, it is also possible to consider for the rigid part the use of a PET (polyethylene terephthalate) or a PETG (polyethylene terephthalate glycolysed), also transparent. In addition, the advantage of PCTA over other transparent polymers, such as PMMA, is a better chemical compatibility with the cosmetic formulas contained inside the tank.
• a flexible part composed of the sealing flange which is made of SEBS (polystyrene-b-poly (ethylene-butylene) -b-polystyrene) or very low density polyethylene or polyurethane. It is also possible to make the flexible part of TPE (thermoplastic elastomer). The flexible part is overmolded on the rigid part.

Alternatively, the piston 1 can be made by tri-injection, with the rounded portions 6 of the lugs 4 constituted by a third material that can be more flexible than the rest of the guide means 3 in order to absorb the radial dimensional dispersions internal walls 14 of the tank 10 inside which it moves. Thus, the radial dimensional tolerances can be less drastic in this case.

As an alternative, this third material may aim at improving the friction of the guiding means 3 on the walls of the tank 10. Thus, with a reservoir 10 made of PETG (glycolized polyethylene terephthalate), it is possible to have contact portions of the means guide 3 made of PE (polyethylene) or PTFE (polytetrafluoroethylene non-commercial Teflon). The piston 1 can therefore be made by tri-injection (SEBS / PP / PTFE).

Finally, for transparent or translucent cosmetic products, it is preferable for the guiding means 3 a material itself transparent such as PETG (polyethylene terephthalate glycolized).

In the second embodiment of the piston 1 according to the invention, shown in FIGS. Figures 2a and 2b , the piston 1 consists of three parts assembled. The sealing means 2 and the guiding means 3 are thus found as in the first embodiment, to which is added a connecting piece 7 mounted in force in the guiding means 3. More precisely, this connecting piece 7 is of square shape, and has outer dimensions slightly larger than the inner dimensions of the base 8. It should be noted that the base 8 is a hollow part. The base 8 thus accommodates within it, forcing, the connecting piece 7. The sealing means 2 are sandwiched between the connecting piece 7 and the base 8.

In the third embodiment of the piston 1 according to the invention, shown in FIGS. Figures 3a and 3b the piston 1 consists of a mono-injected piece to which is added a 2 ring or quadrilobe. This seal 2 constitutes the sealing means 2.

In this case, the piston 1 consists of a single rigid piece, preferably PP (polypropylene) made by mono-injection, and comprising a groove 9 in which is inserted the O-ring 2 sealing the piston 1 on the wall internal tank 10. Such a ring 2 or quadrilobe, for example silicone, has the advantage of providing a good elastic response regardless of the local curvature of the tank 10 (that is to say round or square or square, triangular or other, and with rounded corners or not), as well on a right part as on a rounded part.

In these three embodiments reviewed, the piston 1 has the same general external appearance, and has an improved reproduction rate thanks to the cube 5 projecting from the base 8. This rate of restitution is further improved thanks to the presence of a complementary female shape 11 to the guide means 3 of the piston 1 present at the upper end 13 of the reservoir 10, that is to say opposite the bottom 12 of the reservoir 10.

This complementary shape 11 can be provided directly in the neck 13 of the reservoir 10, or in a ring 15 cooperating with the neck 13 of the reservoir 10. In all cases, it is a surface against which the piston 1 comes into contact. limit stop. This surface has a shape complementary to that of the piston 1.

Such a complementary shape 11 is visible to Figures 4a to 4c . The upper end 13 of the reservoir 10 is provided with this complementary female form. It comprises recesses and recesses in which are housed the legs 4, their rounded ends 6, and the cube 5 projecting piston 1. Due to this complementarity, there is almost no fluid trapped between the piston 1 and the upper part 13 of the reservoir 10 when the piston 1 reaches the limit stop as is visible on the figure 4e .

In the Figures 4a to 4e , the guide means 3 of the piston 1 are oriented towards the upper part of the reservoir 10 and the piston 1 translates from the bottom 12 of the reservoir 10 to the upper part 13 of the reservoir 10, until it is housed in the female form 11 provided for this purpose.

In these three embodiments, a flat pump deformable membrane, fixed flat on the top of the tank 10, and therefore does not enter the tank 10, is used.

In the fourth embodiment of the piston 1 according to the invention, shown in FIGS. Figures 5a and 5b , the piston 1 has a round profile and no longer square.

In this case, its base 8 is frustoconical and has four legs 4 extending obliquely from the base 8, and distributed equidistant from each other all around the base 8.

This base 8 has a central cylindrical orifice extending through a central frustoconical opening 18 flaring towards the upper end of the base 8, that is to say towards the top 13 of the reservoir 10.

The sealing means 2 consist of a flat sealing disc in which the base 8 is positioned, the latter being fixed by gluing to the disc.

However, like the first embodiment, this piston could be formed by bi injection instead of bonding.

This piston 1 is adapted to be housed in a complementary form 11 female provided for this purpose, not in the upper part 13 of the tank 10 but in a ring 15 mounted in the upper part 13 of the tank 10 and in which it is possible to fix a dispensing pump of the fluid product. This ring 15 enters the reservoir 10.

This complementary form 11 female comprises a central frustoconical portion being housed in the frustoconical central orifice 18 of the base 8, and comprises four hollow wings 16 inside which can be housed the lugs 4 of the piston 1. The central orifice cylindrical meanwhile is provided for housing the pump body which is immersed in the tank 10.

In figure 5c the piston is mounted in the reservoir 10. There is no fluid, so the piston is entirely visible from the outside, and in particular the sealing line formed by the sealing means 2, as well as that the guide points formed by the free ends 6 of the legs 4.

When an opaque lotion 23 is poured into the reservoir 10, it envelops the piston 1, and the latter becomes invisible. Only the sealing line remains visible. Guiding points are also invisible.

In this fourth embodiment, the main disadvantage is to have to angularly index the piston 1 relative to the ring 15 during its assembly in the tank 10, so that at the end of the stroke of the piston 1, the male and female shapes are vis-à-vis, that is to say that the lugs 4 of the piston 1 are vis-à-vis the flanges 16 of the ring 15.

Hence the idea of the fifth embodiment of the piston 1 according to the invention, shown in FIGS. Figures 6a and 6b , where the complementary form 11 female in which is housed the piston 1 is provided with V-shaped ramps 19 connecting two wings 16 adjacent to guide the legs 4 in the wings 16 by indexing them correctly. More specifically, the ring 15 is provided with inclined walls 19 on which the lugs 4 for guiding the piston 1 rest, which leads to a rotation of the piston 1 during its axial displacement in the tank 10, inducing a self-alignment structures of the guide means 3 with the female structure of the ring 15. Thus, the guide means 3 are themselves guided.

In this fifth embodiment, piston 1 is for example made in mono-injection, and comprises a groove 9 in which is inserted a ring 2 sealing the piston 1 on the wall of the tank 10.

The piston 1 has a round profile. Unlike the fourth embodiment, the piston 1 has no central orifice, but instead has a protruding shape 5 for limiting the dead volume, as was the case for the first three embodiments.

This shape 5 corresponds to an ovoidal section, from which the four guide tabs 4 extend directly.

The complementary shape 11 thus contains an ovoid-shaped hollow for housing the shape 5, as well as four wings 16 for housing the legs 4.

Thanks to the ramps 19 provided between the flanges 16, it is possible to initially position the piston 1 within the tank 10 without any angular indexing, the ramps 19 fulfilling this angular indexing function at the end of the stroke of the piston 1.

In the sixth embodiment of the piston 1 according to the invention, represented in figure 7 , the piston 1 has a circular section and therefore is mounted in a tank 10 of round section. This piston 1 comprises a cylindrical base 8 of which four tabs 4 are distributed equidistant around the base 8. A cylindrical shape 5 protrudes from the base 8 along the legs 4 to improve the rate of return of the fluid. The sealing means 2 extend all around the base 8, and consist more precisely of a disc 2 on which the base 8 rests.

In a variant, the tabs 4 could protrude from the disk 2 directly, the disk 2 itself constituting the base 8. In this case, the sealing means 2 and the base 8 are merged. This may be the case in other embodiments mentioned in the present description.

As in the case of the first embodiment, the piston 1 consists of a single piece that can be bi-injected or tri-injected.

In the seventh embodiment of the piston 1 according to the invention, represented in figure 8 , the piston 1 has an external shape equivalent to that of the sixth embodiment.

The piston 1 is this time made in three pieces, as was the case in the second embodiment, with a connecting piece 20 which this time is not mounted in force but which is snapped into the base 8 of the guiding means 3. The sealing means 2 are clamped between the connecting piece 20 and the base 8.

In the eighth embodiment of the piston 1 according to the invention, represented in figure 9 the piston 1 also has a circular section.

The piston 1 comprises a cylindrical base 8 having an upper periphery 21 which extend the guide lugs 4. In this case, there are seven guide lugs 4. These tabs 4 are oriented tangentially to the base 8, all in the same direction of rotation.

This piston 1 has a hollow upper surface 22 in the form of a truncated cone, to accommodate a purge ring (not shown) mounted on the end of a pump (not shown).

This piston 1 consists of a single piece, obtained by bi-injection, or tri-injection.

The ninth embodiment of the piston 1 according to the invention, represented in Figures 10a to 10b , is close to the eighth embodiment of the figure 9 .

The piston 1 also has a circular section.

The piston 1 comprises a cylindrical base 8 having an upper periphery 21 which extend the guide lugs 4. In this case, there are seven guide lugs 4. These tabs 4 are oriented tangentially to the base 8, all in the same direction of rotation.

This piston 1 has a hollow upper surface 22 in the form of a truncated cone, to accommodate a purge ring (not shown) mounted on the end of a pump (not shown).

This ninth mode differs from the eighth mode in that the sealing means 2 consist of a flexible skirt 30 mounted tightly in the reservoir. The end of this skirt 30 forms a sealing lip adapted to be pressed against the inner wall of the tank.

The sealing means 2 thus have a geometry that gives them greater flexibility with respect to the sealing means 2 of the eighth embodiment. It is thus possible to produce these sealing means 2, and the rest of the piston 1, polyethylene (PE). Thus, this piston 1 is made of a single material and made in mono-injection. This geometry including the flexible skirt 30 thus simplifies the injection process compared to other embodiments while maintaining good performance in terms of sealing and guiding.

In the tenth embodiment of the piston 1 according to the invention, shown in FIGS. Figures 11a to 11e the piston 1 is made in a modular manner.

Firstly, a mold produces a ribbon of guide lugs 4 which extend from a base 24, for example of square or rectangular or circular section, as can be seen in FIG. figure 11a . Preferably, these tabs 4 are interconnected by a breakable link.

Furthermore, a piston 1 having the shape of a circular disc (or a square or other form) serving as base 8, is provided with housings 17 adapted to receive the bases 24 of the guide lugs 4, as shown in FIG. figure 11b .

The bases 24 of the legs 4 are mounted in force or snapped into the housings 17.

This modular embodiment allows to equip, with the same guide lugs 4, pistons 1 of different diameters and different sections. A piston 1 of larger perimeter will thus be equipped with a greater number of legs 4.

So, on the figure 11c , the piston 1 has a small perimeter and is equipped with five legs 4. On the figure 11d , the piston 1 has a mean perimeter is equipped with seven legs 4. Finally, on the figure 11e , the piston 1 has a large perimeter is equipped with nine legs 4.

In the eleventh embodiment of the piston 1 according to the invention, shown in FIGS. Figures 12a and 12b , the piston 1 comprises guide means 3 retractable, collapsible or flexible.

In order to improve the rate of return to product, on the one hand by economizing on the complementary female shape embodiment of the guiding means 3 on the pump mounting ring 15 or on the reservoir 10 of the product, and on the other hand, while maintaining a sufficient axial extension of the guiding means 3 for effective guiding, it is possible to provide flexible or hinged tabs 4 that are adapted to fold when they come into abutment on the top 13 of the hinge. Another advantage is that, since the stroke of the piston 1 is greater than with non-deformable rods, the surface of the tank 10 available to cosmeticians for display is increased.

In the embodiments 1 to 11, it would also be possible to turn the piston 1 in the tank 10, that is to say, to ensure that the guide means 3 are oriented towards the bottom 12 of the tank 10. In this case, the guide means 3 are not in contact with the fluid contained in the reservoir 10. Only the base 8 and the sealing flange 2 are in contact with the fluid product.

In this case, the base 8 is closed with a surface oriented in the same plane as the bead, so as to obtain a uniform platform on which is deposited the fluid. Instead of providing a relatively complicated complementary female form, it will be just necessary to close the top 13 of the tank 10 by a flat surface against which the platform of the piston 1 will come into contact, in order to obtain plane contact between the two. surfaces is to ensure that all of the fluid is distributed through the outlet of the reservoir 10.

The twelfth embodiment of the piston 1 according to the invention, shown in FIGS. Figures 13a to 13c , is close to the ninth embodiment of Figures 10a and 10b .

The piston 1 has a circular section.

The piston comprises a cylindrical base 8, corresponding to a ring. The guide lugs 4 extend from the outer surface of the ring. These tabs 4 are oriented tangentially to the base 8, all in the same direction of rotation.

The central portion 26 of the crown is solid, and cup-shaped, that is to say of concave shape, so as to define a housing to accommodate another part of the dispenser with a complementary shape. This other part generally consists of a purge ring 11, which fits snugly with the piston 1 at the end of distribution (that is to say in the upper position of the piston), so as to offer a maximum rate of refund of the product. Indeed, when the shapes are complementary, there is no trapped product in the upper position of the piston, as shown in FIG. figure 13c . In this case, the piston 1 comes into contact with the purge ring 11.

The sealing means 2 consist of a flexible disc 2 whose periphery is curved in a direction opposite to the tabs, said periphery forming a sealing lip 25.

The base 8 is mounted on said disk 2. The base 8 and the disk 2 each have a concave central portion, the central portion 27 of said disk 2 according to the profile of the central portion 26 of the base 8.

In this twelfth embodiment of the piston, the central portion 26 of the base 8 is located under the sealing line formed by the sealing lip 25. This central portion 26 is clearly visible through the reservoir 10. this central portion 26 increases the total height of the bottle by the same amount. As the piston 1 is larger, it takes up space normally dedicated to cosmetics. It is therefore necessary to increase the size of the tank 10 to accommodate the amount of cosmetic product initially provided.

The thirteenth embodiment of the piston 1 according to the invention, shown in FIGS. Figures 14a to 14c is close to the twelfth embodiment, and overcomes the disadvantage of the large piston.

The piston 1 has a circular section.

The piston 1 comprises a cylindrical base 8, corresponding to a ring. The guide tabs 4 extend from the outer surface of the crown. These tabs 4 are oriented tangentially to the base 8, all in the same direction of rotation.

The central part of the crown is empty. More precisely, the crown defines a central recess.

The sealing means 2 consist of a flexible disc 2 whose periphery is curved in a direction opposite to the tabs, said periphery forming a sealing lip 25. The base 8 is mounted on said disc 2.

This disc 2 has a central portion 27 of convex shape, penetrating inside the central recess of the base 8. This central portion 27 corresponds to a dome 27. This flexible dome 27 is thus located in the center of the base 8 rigid. The dome 27 is thus hidden inside the base 8, and is not visible from the outside of the tank 10. The piston 1 is thus significantly less bulky than in the previous embodiment. This is particularly represented in Figures 14a and 14b .

This central portion 27 of the disc 2 is flexible enough to be reversed under the effect of a force applied to the top of the dome. In this case, the central portion 27 takes a concave shape, like that of the twelfth embodiment. In general, the force will be applied by a purge ring 11 located in the upper part of the reservoir 10, and having a shape complementary to that of the piston 1, as explained in the twelfth embodiment. In this case, the purge ring 11 will have a shape complementary to that of the inverted dome of the disk 2. Thus, near the high position of the piston 1, the dome 27 comes into contact with the purge ring 11 and gradually returns to adopt at the end of displacement of the piston inverted curvature, which allows to obtain a complementarity of the shapes of the piston 1 and the purge ring 11, to maximize the rate of return of the product. The inverted dome is represented on the figure 14c .

In the ninth embodiment, the twelfth embodiment, and the thirteenth embodiment, the sealing means 2 are formed by a sealing lip (reference 25 and end of the skirt 30) which comes into contact with the inner wall of the reservoir 10. This lip is bent, which provides greater flexibility and allows it to absorb the gap between the lower and upper diameters of the reservoir 10. In fact, the reservoir 10 is a molded piece and present a body interior needed to demold the room. There can therefore be dimensional deviations within the tank 10.

In addition, the curved shape of the sealing portion is less visible than a shape having sharp edges, in that it diffracts less light. Therefore, the sealing lip is very discrete through the tank 10.

Preferably, in the embodiments comprising a sealing lip, the bottom 12 of the reservoir 10 is an insert snapped into the body of the reservoir, as illustrated in FIGS. figures 13b and 14b . This bottom could also be overmoulded with the tank body or simply be integral with the tank body.

This bottom 12 has a complementary shape of the piston 1 in order to support the underside of the sealing lip, so as to withstand a vacuum leak test or leakage of a product tending to expand. In this case, during a vacuum test, the airless bottle filled with product with the piston in the low position is placed in a vacuum chamber, for example to simulate the pressure conditions in aircraft baggage compartments. usually at low pressure, and a possible product leak is detected during the test. Depression is transmitted to the piston through a hole in the bottom of the bottle.

In the prior art, the follower pistons of the airless systems generally consist of two superimposed lips and at a distance from one another. As the product in the tank is at atmospheric pressure, the lower lip opens and loses contact with the inner wall of the tank under the effect of vacuum. The emptiness is communicated to the space between the two lips. The upper lip, unlike the lower lip, is strongly against the wall, preventing product leakage.

The piston 1 according to the invention comprises only one lip, similar to the lower lip of the prior art, which moreover has a curvature favoring during the test its opening, and which therefore does not benefit from the beneficial effect of the upper lip in terms of resistance to leakage under vacuum conditions.

To remedy this, the bottom 12 of the bottle comprises a peripheral groove 28 in which is housed the piston lip and prevents it from deforming and losing contact with the tank wall in case of depression.

Preferably, in all embodiments, the piston 1 is made of a material with microbiocidal properties.

The microbiocidal properties of the material can be obtained by diffusion in the product of an antimicrobial agent, for example on an organic basis such as Trichlosan (trade name of Melcoplast) or on a silver base, or mineral. In particular, the material may comprise at least one polyolefin, for example polyethylene, polypropylene and / or polystyrene, which is loaded with at least one antimicrobial agent.

The microbiocidal properties of the material can also be obtained by contacting the product with a microbiostatic agent, for example by using a metallic material such as a copper or zinc alloy or a material comprising at least one polyolefin charged with such metal particles or having has undergone a surface treatment by fluorination, zinc plating or copper plating.

The microbiocidal properties of the material can also be obtained by irradiating the piston with radiation of suitable wavelength, in particular by means of a material which exhibits photoluminescence properties after exposure to external light. In particular, the material may be based on at least one polyolefin charged with at least one additive capable of emitting photoluminescent radiation which has a wavelength of between 250 and 260 nanometers, and in particular of 254 nanometers, which corresponds to to the order of magnitude of sterilizing ultraviolet radiation.

With respect to the above description, the optimal dimensional relationships for the parts of the invention, including variations in size, materials, shapes, function and modes of operation, assembly and use are considered apparent and obvious to those skilled in the art, and all relationships equivalent to what is illustrated in the drawings and what is described in the specification are intended to be included in the present invention.

Claims (17)

Piston 1 for reservoir 10 of a distributor of a fluid product without air intake, having a central axis X and comprising: - Sealing means 2; guiding means 3; characterized in that said sealing means 2 extend in a plane orthogonal to the axis X and define a single external sealing line in a closed loop, distal from the axis X, capable of coming into contact with a inner wall 14 of the reservoir 10, and in that said guide means 3 comprise a base 8 from which extend a plurality of lugs 4 having free ends 6 defining outer guide points, distal to the X axis, capable of to come into contact with the inner wall 14 of the tank 10. Piston 1 according to the preceding claim, characterized in that said sealing means 2 develop around said base 8. Piston 1 according to one of the preceding claims, characterized in that it has at least three lugs 4. Piston 1 according to one of the preceding claims, characterized in that the guide means 3 are mainly designed in a rigid material of the PP or PET or PCTA type, while the sealing means 2 are designed in a flexible material of the type SEBS, or very low density PE, or polyurethane. Piston 1 according to one of the preceding claims, characterized in that it consists of a single piece obtained by injection of one or more materials. Piston 1 according to one of the preceding claims, characterized in that the free end 6 of the lugs 4 has a rounded shape. Piston 1 according to one of the preceding claims, characterized in that it is designed in an intrinsically colored material. Piston 1 according to one of the preceding claims, characterized in that it has rectilinear lateral sides connected in pairs by roundings. Piston 1 according to one of the preceding claims, characterized in that the sealing means 2 consist of a flexible disk whose periphery is curved in a direction opposite to the tabs, said periphery forming a sealing lip 25. Piston 1 according to the preceding claim, characterized in that said base 8 comprises a solid central portion 26 mounted on said disk, the base 8 and the disc each having a concave central portion, the central portion 27 of said disk following the profile of the central portion 26 of the base 8. Piston 1 according to claim 9, characterized in that said base 8 corresponds to a crown defining a central recess, the disc having a central portion 27 of convex shape penetrating inside the central recess of the base 8. Piston 1 according to the preceding claim, characterized in that the central portion 27 of convex shape of the disk is adapted to reverse to take a concave pace. Fluid dispenser without air intake comprising a reservoir 10 adapted to store the fluid and housing a piston 1 as described in the preceding claims, the reservoir 10 having a bottom 12 and a neck 13 located opposite the bottom 12, said sealing means 2 of the piston 1 being in contact with an inner wall 14 of the reservoir 10 forming a nip, and the free ends 6 of the lugs 4 being in contact with the inner wall 14 of the reservoir 10 forming contact points. Dispenser according to the preceding claim, characterized in that the piston 1 moves in the reservoir 10 between a lower proximal position of the bottom 12 of the reservoir 10 and a proximal upper position of the neck 13 of the reservoir 10, the dispenser having a complementary shape 11 to the piston 1 in the vicinity of the neck 13 of the tank 10. Dispenser according to the preceding claim, characterized in that said complementary shape 11 is formed in the neck 13 itself of the reservoir 10. Dispenser according to claim 14, characterized in that said complementary shape 11 is formed in a ring 15 mounted on or in the neck 13 of the reservoir 10. Dispenser according to one of claims 13 to 16, characterized in that the sealing means 2 of the piston comprise a sealing lip 25, the bottom 12 of the tank 10 having a peripheral groove 28 in which is housed said lip of sealing 25.

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