Piston for a reservoir of a fluid product dispenser without air intake

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. Said sealing means 2 extend in a plane orthogonal to the axis X and define a single external closed-loop sealing line, distal to the axis X, suitable for contacting an internal wall 14 of the reservoir 10, and in that said guiding means 3 comprise a base 8 from which extend a plurality of lugs 4 having free ends 6 defining external guiding points, distal to the axis X, suitable for contacting the internal wall 14 of the reservoir 10.The sealing means 2 consist of a flexible disc 27 whose perimeter is curved in a direction opposite to the legs, said perimeter forming a sealing lip 25, said base 8 having a solid central part 26, mounted on said disc, the base 8 and the disc each having a central part with a concave appearance, the central part 27 of said disc following the profile of the central part 26 of the base 8.

Description

Field of invention

[0001] 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 dispenser of a fluid product without air intake comprising a reservoir capable of storing the fluid product and housing such a piston.

[0002] 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

[0003] Airless dispensers (no air in the tank) are equipped with so-called "follower" pistons. They are in contact with the product and rise with each dispensing under the effect of the depression in the tank induced by this dispensing.

[0004] These pistons generally comprise two sealing lips pressed against the side wall of the tank, axially spaced from each other in order to also provide a guiding function for the piston in its travel in the tank. Indeed, the latter must remain oriented in such a way 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 crown having a certain height, corresponding to the height of the lip, and clearly visible from outside the tank.

[0005] The volume between the two lips is made up of air and makes the lateral surface of the piston which extends between these two lips perfectly visible when the walls of the tank are transparent or translucent.

[0006] The tank is preferably made of plastic, for example PETG (polyethylene terephthalate glycol). The tank can also be made of glass. In this case, dimensional tolerances are more difficult to maintain. A drawn glass process is then preferred to ensure compliance with dimensional tolerances.

[0007] The piston is a visible and unsightly mechanical element, perceived as trivially functional, and does not correspond to the image of certain prestigious brands of cosmetic products. The objective of the present invention is to eliminate or at least mitigate this effect.

[0008] The problem to be solved is therefore to hide the piston, to make it invisible or even to make it a mobile aesthetic element, within the tank. Summary of the invention

[0009] The present invention aims to overcome the various drawbacks stated above, by means of a piston for a reservoir of a dispenser of a fluid product without air intake, having a central axis X and conventionally comprising: sealing means; guiding means.

[0010] This piston is mainly characterized in that said sealing means extend in a plane orthogonal to the X axis and define a single external sealing line in a closed loop, distal to the X axis, capable of coming into contact with an internal wall of the reservoir, and in that said guide means comprise a base from which extend a plurality of legs having free ends defining external guide points, distal to the X axis, capable of coming into contact with the internal wall of the reservoir.

[0011] The main idea of this invention is to provide a piston which has a minimum contact surface with the inner wall of the reservoir.

[0012] The lateral ends of the piston consist only of the outer sealing line and the outer guide points. Only these lateral ends will be in contact with the reservoir, and will therefore be visible from the outside by the dispenser user. In the end, there will only be a single contact line and contact points that will be visible to the user through the reservoir.

[0013] Indeed, the existence of the legs to guide the piston allows the fluid product to be inserted between the legs and all around the base, so as to best camouflage the piston. There is therefore no longer any volume of air between two lips as was the case in the prior art, where the body of the piston was then clearly visible.

[0014] The piston of the present invention no longer forms an unsightly sealing crown visible from the outside of a tank. In the claimed piston, the sealing means define a single external sealing line. This single line is thus very discreet compared to the two crowns of the prior art.

[0015] Likewise, the exterior guidance points are very discreet, and barely visible to the user through the tank.

[0016] According to the different embodiments of the invention, which may be taken together or separately: said sealing means are developed around said base. the piston has at least three legs: this prevents the piston from tilting in the tank. the guide means are mainly designed in a rigid material of the PP or PCTA or PET type, while the sealing means are designed in a flexible material of the SEBS, or very low density PE, or polyurethane type: the sealing means must be able to crush against the inner wall of the tank, in order to form a seal and so that the fluid contained in the tank cannot 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 legs 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 can be less drastic.The same applies to the radial dimensional tolerances of the pistons. The piston may consist of a single part obtained by injection of one or more materials: it may be a mono-injected, bi-injected, or tri-injected part for example. The piston may consist of a plurality of parts assembled for example by gluing or snap-fastening or by force fitting. The free end of the lugs has a rounded shape: this shape ensures only almost point contact with the inner wall of the tank, and promotes sliding. The free end of the lugs has a sliding zone: this sliding zone corresponds to a small surface, of the pad type, which ensures slightly greater point contact than in the previous version with the rounded shape, with the inner wall of the tank.This sliding zone improves the piston's sliding in the tank, but the point of contact between the piston and the tank is slightly larger. The piston loses in invisibility what it gains in guidance. The free ends of the tabs are distributed evenly, equidistant from each other: they allow uniform support around the entire perimeter of 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 at a distance from the sealing means: the tabs ensure perfectly horizontal positioning of the piston within the tank. They are sufficiently far from the sealing means, so that the points of contact with the tank are at a distance from the contact line, to ensure optimal guidance of the piston in the tank without the risk of the piston tipping over.the piston has microbiocidal properties: more precisely, the piston is made from at least one material having microbiocidal properties by diffusion of an antimicrobial agent, by contact with a microbiostatic agent and / or by irradiation with radiation of suitable wavelength. the sealing means consist of a flexible bead extending around the base of the piston. the sealing means consist of an O-ring, inserted into 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 sized so that only a small area comes into contact with the interior walls of the bottle, so as to form an external sealing line, and not an external sealing crown.the sealing means consist of a flexible disc whose periphery is curved in a direction opposite to the legs, said periphery forming a sealing lip. said base comprises a solid central part, mounted on said disc, the base and the disc each having a central part of concave appearance, the central part of said disc following the profile of the central part of the base. said base corresponding to a crown defining a central recess, the disc having a central part of convex appearance penetrating inside the central recess of the base. the central part of convex appearance of the disc is capable of reversing to take on a concave appearance. the piston has rectilinear lateral sides connected two by two by rounded edges: the piston may for example be of square, triangular, or other shape. the piston has a circular shape.

[0017] The invention further relates to a fluid dispenser without air intake comprising a reservoir capable of storing the fluid and housing a piston as described above, the reservoir having a bottom and a neck located opposite the bottom, said sealing means of the piston being in contact with an inner wall of the reservoir, forming a contact line, and the free ends of the legs being in contact with the inner wall of the reservoir, forming contact points.

[0018] According to the different embodiments of the invention, which may be taken together or separately: the piston moves in the reservoir between a lower position proximal to the bottom of the reservoir and an upper position proximal to the neck of the reservoir, the distributor 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 reservoir where there is still fluid product while the piston is at the end stop. The rate of restitution of the fluid product is thus improved. said complementary shape is produced in the neck of the reservoir itself: the reservoir itself has the female shape complementary to the means for guiding the piston. said complementary shape is produced 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 fits into the ring.said complementary shape has ramps for guiding and radially indexing the lugs: in particular when the reservoir has a cylindrical inner wall, it is possible that the piston is not initially positioned so that the lugs are opposite the female shapes where they are supposed to be housed within the complementary shape at the end of the piston's stroke, or it is possible that the piston rotates slightly when it rises along the reservoir causing a misalignment of the lugs relative to the female shapes. It is therefore necessary to guide each lug towards its respective female shape. V-shaped inclined walls are therefore provided between the adjacent female shapes, in order to guide each lug towards one of the female shapes, then to angularly index the lugs relative to the female shapes, and so that the piston is finally inserted correctly into the general complementary shape.Concretely, the tabs slide along the ramps, leading to a rotation of the piston during its axial end-of-stroke movement, inducing a self-alignment of the piston guide means with the complementary shape. The guide means are thus themselves guided. The tabs are retractable in contact with the neck of the tank or with a ring mounted on the neck of the tank: the tabs can be flexible and deform, 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 a sufficient axial extension of the tabs relative to the sealing means to ensure effective guidance.The advantage of retractable legs is that the piston stroke is greater than with non-deformable legs because there is no space lost by a complementary shape, and thus the surface of the reservoir available to the cosmetician for display (product name, etc.) is increased. The piston is made of a material with 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 perfume which is composed essentially of ketones and alcohols. The piston is thus "invisible" in the perfume. The piston is designed in a material containing fluorine.the piston is coated with a decoration, of the film type, affixed to at least part of its external surface, except on its sealing line: if the decoration is of a different color from that of the fluid product, then the piston is visible but becomes a movable 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 can be decorated on its entire external surface, except on its sealing line, by a decorative film. the piston is designed in an intrinsically colored material: when the fluid product is transparent and colored, the piston can be of a color adjusted to the color of the fluid product, 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 product. the legs of the piston are oriented towards the bottom of the tank: in this case, the legs will not come to a stop at the end of their travel against the upper part of the tank. Only the surface of the base oriented towards the neck of the tank will come to a stop at the end of their travel. In this case, the legs are located under the sealing means, and are not in contact with the fluid product, and are therefore clearly visible. Preferably, the piston will be decorated in this case. the sealing means consist of a flexible tube extending around the base of the piston, and matching the internal shape of the tank: the tube can be 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 said sealing lip is housed. Presentation of figures

[0019] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the detailed explanatory description which follows, of at least one embodiment of the invention given by way of purely illustrative and non-limiting example, with reference to the appended schematic drawings.

[0020] 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 comprising a complementary shape capable of receiving a piston according to the first, second and third embodiments of the invention; figure 4drepresents the piston in its initial position at the bottom of the tank as illustrated in Figures 4a to 4c ; there Figure 4e represents the piston in its final position at the top of the reservoir 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; Figures 6a and 6b represent the piston and its complementary shape according to a fifth embodiment of the invention; 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 Figure 9 represents the piston according to an eighth embodiment of the invention Figures 10a to 10b represent the piston according to a ninth embodiment of the invention; the Figures 11a to 11e represent the piston according to a tenth embodiment of the invention; the Figures 12a to 12brepresent 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

[0021] In the remainder of the description, elements having an identical structure or similar functions are designated by the same references.

[0022] Dispensers without air intake, called "airless" (absence of air in the tank 10), are equipped with so-called "follower" pistons. They are in contact with the product and rise with each dispensing under the effect of the depression in the tank induced by this dispensing. Several embodiments of such pistons according to the invention will be described below.

[0023] With reference to all the figures, the piston 1 is composed in particular of sealing means 2 and guide means 3. These sealing means 2 and these guide means 3 have ends which define an external envelope of the piston 1, capable of coinciding with the internal volume of a reservoir 10 into which the piston 1 is introduced.

[0024] In particular, if the inner wall 14 of the reservoir 10 is cylindrical in shape, then the outer casing of the piston 1 will also be cylindrical in shape.

[0025] In the same way, if the inner wall 14 of the reservoir 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 lateral inner walls 14 of the reservoir 10.

[0026] The sealing means 2 of the piston 1 make it possible to divide the reservoir 10 into two sealed zones relative to each other. In particular, when the reservoir 10 contains fluid product, the sealing means 2 allow the fluid product 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.

[0027] The guide means 3 of the piston 1 make it possible to maintain the piston 1 in a stable position transversely inside the reservoir 10, and allow the piston 1 to move axially inside the reservoir 10 while remaining in stable positions inside the reservoir 10 over its entire travel.

[0028] THE Figures 1a to 1d illustrate a first embodiment of the piston 1 according to the invention.

[0029] In this first mode, piston 1 has a square shape, that is to say square with the four rounded corners.

[0030] This piston 1 has a base 8 from which twelve guide tabs 4 extend, each ending in a free end 6 of rounded shape. The base 8 has four faces, three tabs 4 extending from each face. On each face: a leg 4 extends in the center of the face; a leg 4 extends on the periphery of the face and in the direction of an adjacent rounded corner, for example this leg 4 extends on the left of the face and in the direction of the left corner; a leg 4 extends on the periphery of the face in the direction of another adjacent rounded corner, for example this leg 4 extends on the right of the face and in the direction of the right corner.

[0031] 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.

[0032] Each face therefore has the same number of legs 4, with the same orientations, and with the same shapes.

[0033] The more legs 4 there are, the less risk there is of the piston 1 tipping over within the reservoir 10.

[0034] The base 8 and the legs 4 form what are called the guide means 3 of the piston 1.

[0035] Around the base 8 extends an annular flange which forms what is called the sealing means 2 of the piston 1.

[0036] Piston 1 has a central axis X as defined in the Figure 1d . Legs 4 develop around this X axis and are located in the same plane P transverse to this X axis.

[0037] When the piston 1 is inserted inside a reservoir 10, as for example illustrated in the figure 4d, it is clearly visible that the sausage is in contact with the inner side walls 14 of the tank 10, and the rounded shapes 6 of the legs 4 are also in contact with the inner side walls 14 of the tank 10.

[0038] The sausage has a curved edge so as to form only one external line of contact with the reservoir 10. This line is very discreet when observing the piston 1 through the transparent or translucent reservoir 10.

[0039] The rounded shapes 6 of the legs 4 each form a point contact with the interior walls 14 of the tank 10. These point contacts consist of points of varying size depending on the shape of the rounded part, and which are therefore also very discreet visually from the outside of the tank 10.

[0040] The larger the diameter of the rounded part, the larger the contact point will be. Conversely, the smaller the diameter of the rounded part, the smaller the contact point will be. It is also possible to consider small pad-type surfaces at the ends of the legs 4. The contact point will be a little larger, but the piston 1 will be better guided.

[0041] Ultimately, when the piston 1 is inserted into the reservoir 10, the user will only see an outer line and a plurality of points, in this case 3 per face, through the wall of the reservoir 10.

[0042] The legs 4 extend sufficiently far from the sealing means 2 to ensure better stability in the movement of the piston 1 within the reservoir 10 and to avoid any risk of the piston 1 tipping over.

[0043] More specifically, here are the dimensional parameters, as illustrated in Figure 1c And 1d : H = axial distance between a guide contact point and a sealing contact point located just below. Φ = largest dimension of the sealing means 2. L = transverse length of a leg 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.

[0044] Preferably, H / Φ > 1 / 4: this allows for good guidance.

[0045] The parameter L conditions the thickness e of fluid product masking the piston 1: for a very opaque product, we can consider a low thickness (e = or < 1 mm) for a more translucent product we will choose a thickness 1 < e < 3 mm

[0046] A greater thickness would result in a volume of product that would be impossible to return at the end of use of the dispenser, as illustrated in Figure 4e and explained below.

[0047] The legs 4 must ensure the upper guidance of the piston 1 by point supports, replacing a classic continuous lip.

[0048] The length of the legs 4 from the contact point 6 to the base determines their flexibility intended to absorb dimensional variations due to: to manufacturing tolerances; to the variation in diameter between the bottom of the tank and the top of the tank due to the tank taper.

[0049] The length L of the legs 4 must be: sufficiently large to provide the elasticity necessary to absorb dimensional variations; sufficiently short to ensure a minimum of rigidity and ensure the guiding function and prevent the piston 1 from tilting.

[0050] This is a compromise.

[0051] 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.

[0052] 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 2 ml.

[0053] In the case of the figure 4d , the piston 1 is located in the bottom 12 of the reservoir 10, in the initial position. When fluid product is poured inside the reservoir 10, this product comes to rest above the piston 1 and is inserted between the legs 4, so as to camouflage them.

[0054] As product is dispensed from this reservoir 10, by means of dispensing means comprising for example a pump and a push button mounted on the reservoir, the whole forming a dispenser, the piston 1 rises along the reservoir 10 until it reaches the upper stop towards the upper end of the reservoir 10, corresponding to a neck 13, which is opposite the bottom 12 of the reservoir 10, as illustrated in Figure 4e .

[0055] To avoid 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 product and which can no longer be dispensed since the piston 1 is already at the end of its travel, it is planned to equip the piston 1 with a shape 5 which fills this dead volume and whose upper surface is located in the plane P in which all the rounded parts 6 of the legs 4 are located.

[0056] In the first embodiment of the invention, this shape 5 consists of a cube 5 extending axially between the legs 4. The upper surface of the cube 5 has the same axial position as the end of the legs 4. The cube 5 comes into contact with the upper end 13 of the reservoir 10. This cube 5 therefore aims to improve the rate of restitution of the fluid product by reducing the dead volume, that is to say by preventing the product stored between the legs 4 from being impossible to dispense when the piston 1 is in the high position, that is to say at the end of its stroke.

[0057] However, there will always be a ring of thickness L (as explained previously) located under the legs 4 which cannot be restored despite the complementary shape 11 of the upper end 13.

[0058] Piston 1 is made by dual injection.

[0059] In this case, piston 1 includes: a rigid part composed of legs 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 discreet piston use when the cosmetic formula inside the reservoir is opaque. On the other hand, for translucent formulas, PCTA (acid modified polycyclohexylene dimethylene terephthalate) is preferred, which is an ultra transparent polymer, with the appearance of a crystal. As an alternative, the use of PET (polyethylene terephthalate) or PETG (glycolyzed polyethylene terephthalate), also transparent, can also be considered for the rigid part. In addition, the advantage of PCTA over other transparent polymers, such as PMMA, is better chemical compatibility with the cosmetic formulas contained inside the reservoir.a flexible part composed of the sealing bead which is made of SEBS (polystyrene-b-poly(ethylene-butylene)-b-polystyrene) or very low density polyethylene, or even polyurethane. It is also possible to make the flexible part of TPE (thermoplastic elastomer). The flexible part is overmolded onto the rigid part.

[0060] Alternatively, the piston 1 may be produced using tri-injection, with the rounded parts 6 of the legs 4 made of a third material which may be more flexible than the rest of the guide means 3 in order to absorb the radial dimensional dispersions of the inner walls 14 of the reservoir 10 inside which it moves. Thus, the radial dimensional tolerances may be less drastic in this case.

[0061] Alternatively, this third material may aim to improve the friction of the guide means 3 on the walls of the reservoir 10. Thus, with a reservoir 10 made of PETG (polyethylene terephthalate glycol), it is possible to have contact parts of the guide means 3 made of PE (polyethylene) or PTFE (polytetrafluoroethylene of non-commercial Teflon). The piston 1 may therefore be made by tri-injection (SEBS / PP / PTFE).

[0062] Finally, for transparent or translucent cosmetic products, a material that is itself transparent, such as PETG (polyethylene terephthalate glycol), will be preferred for the guiding means 3.

[0063] In the second embodiment of the piston 1 according to the invention, shown in Figures 2a And 2b, the piston 1 consists of three assembled parts. We thus find the sealing means 2 and the guide means 3 as in the first embodiment, to this is added a connecting piece 7 mounted by force in the guide means 3. More precisely, this connecting piece 7 is of square shape, and has external dimensions slightly larger than the internal dimensions of the base 8. It should be noted that the base 8 is a hollow part. The base 8 thus accommodates within it, by forcing, the connecting piece 7. The sealing means 2 are clamped between the connecting piece 7 and the base 8.

[0064] In the third embodiment of the piston 1 according to the invention, shown in Figures 3a And 3b , the piston 1 consists of a single-injected part to which a toric or quadrilobe seal 2 is added. This seal 2 constitutes the sealing means 2.

[0065] In this case, the piston 1 consists of a single rigid part, preferably made of PP (polypropylene) produced by single injection, and comprising a groove 9 in which the O-ring 2 is inserted, sealing the piston 1 against the internal wall of the reservoir 10. Such an O-ring or quadrilobe 2, for example made of silicone, has the advantage of providing a good elastic response whatever the local curvature of the reservoir 10 (i.e. round or square or round, triangular or other, and with rounded corners or not), both on a straight part and on a rounded part.

[0066] In these three embodiments reviewed, the piston 1 has the same general external appearance, and has an improved restitution rate thanks to the cube 5 projecting from the base 8. This restitution rate 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.

[0067] 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 to a stop at the end of its travel. This surface has a complementary shape 11 to that of the piston 1.

[0068] Such a complementary form 11 is visible at Figures 4a to 4c. The upper end 13 of the reservoir 10 is provided with this complementary female shape. It comprises hollows and recesses in which the legs 4, their rounded ends 6, as well as the cube 5 projecting from the piston 1 are housed. Thanks to this complementarity, there is almost no more fluid trapped between the piston 1 and the upper part 13 of the reservoir 10 when the piston 1 reaches the end of its travel as can be seen in the figure. Figure 4e .

[0069] 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 towards the upper part 13 of the reservoir 10, until it is housed in the female shape 11 provided for this purpose.

[0070] In these three embodiments, a flat pump with a deformable membrane, fixed flat on top of the tank 10, and which therefore does not penetrate into the tank 10, is used.

[0071] In the fourth embodiment of the piston 1 according to the invention, shown in Figures 5a and 5b , piston 1 has a round profile and no longer square.

[0072] In this case, its base 8 is truncated in shape and it has four legs 4 extending obliquely from the base 8, and distributed equidistant from each other all around the base 8.

[0073] This base 8 has a cylindrical central orifice extending into a central orifice of truncated cone shape 18 widening towards the upper end of the base 8, that is to say in the direction of the top 13 of the reservoir 10.

[0074] 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.

[0075] However, just like the first embodiment, this piston could be formed by bi-injection instead of gluing.

[0076] This piston 1 is capable of being housed in a complementary female form 11 provided for this purpose, not in the upper part 13 of the reservoir 10 but in a ring 15 mounted in the upper part 13 of the reservoir 10 and in which it is possible to fix a fluid product distribution pump. This ring 15 enters the reservoir 10.

[0077] This female complementary shape 11 comprises a central truncated cone-shaped part which fits into the central truncated cone-shaped orifice 18 of the base 8, and comprises four hollow wings 16 inside which the legs 4 of the piston 1 can fit. The central cylindrical orifice is provided to fit the pump body which is immersed in the reservoir 10.

[0078] In Figure 5c, the piston is mounted in the reservoir 10. There is no fluid product, so the piston is entirely visible from the outside, and we can see in particular the sealing line formed by the sealing means 2, as well as the guide points formed by the free ends 6 of the legs 4.

[0079] 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. The guide points are also invisible.

[0080] In this fourth embodiment, the main drawback is having to angularly index the piston 1 relative to the ring 15 when it is mounted in the reservoir 10, so that at the end of the stroke of the piston 1, the male and female shapes are opposite each other, that is to say the legs 4 of the piston 1 are opposite the wings 16 of the ring 15.

[0081] Hence the idea of the fifth embodimentof the piston 1 according to the invention, shown in Figures 6a and 6b , where the complementary female shape 11 in which the piston 1 is housed is provided with V-shaped ramps 19 connecting two adjacent wings 16 in order to be able to guide the legs 4 in the wings 16 by indexing them correctly. More precisely, the ring 15 is provided with inclined walls 19 on which the guide legs 4 of the piston 1 rest, which leads to a rotation of the piston 1 during its axial movement in the reservoir 10, inducing a self-alignment of the structures of the guide means 3 with the female structure of the ring 15. Thus, the guide means 3 are themselves guided.

[0082] In this fifth embodiment, piston 1 is for example produced by single injection, and comprises a groove 9 in which is inserted an O-ring 2 sealing the piston 1 on the wall of the reservoir 10.

[0083] The piston 1 has a round profile. Unlike the fourth embodiment, the piston 1 does not have a central orifice, but on the contrary has a projecting shape 5 serving to limit the dead volume, as was the case for the first three embodiments.

[0084] This shape 5 corresponds to an ovoid section, from which the four guide legs 4 extend directly.

[0085] The complementary shape 11 therefore contains an ovoid-shaped hollow to house the shape 5, as well as four wings 16 to house the legs 4.

[0086] Thanks to the ramps 19 provided between the wings 16, it is possible to initially position the piston 1 within the reservoir 10 without any angular indexing, the ramps 19 fulfilling this angular indexing function at the end of the stroke of the piston 1.

[0087] In the sixth embodiment of the piston 1 according to the invention, represented in Figure 7, the piston 1 has a circular section and is therefore mounted in a reservoir 10 of round section. This piston 1 comprises a cylindrical base 8 from which extend four legs 4 distributed equidistantly around the base 8. A cylindrical shape 5 projects from the base 8 along the legs 4 to improve the rate of restitution of the fluid product. The sealing means 2 extend all around the base 8, and consist more precisely of a disc 2 on which the base 8 rests.

[0088] In a variant, the legs 4 could protrude from the disc 2 directly, the disc 2 itself then 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 cited in the present description.

[0089] As in the case of the first embodiment, the piston 1 consists of a single part which can be bi-injected or tri-injected.

[0090] 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.

[0091] 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 force-fitted but which is snapped into the base 8 of the guide means 3. The sealing means 2 are clamped between the connecting piece 20 and the base 8.

[0092] In the eighth embodiment of the piston 1 according to the invention, represented in Figure 9 , piston 1 also has a circular section.

[0093] The piston 1 comprises a cylindrical base 8 having an upper circumference 21 from which the guide tabs 4 extend. In this case, there are seven guide tabs 4. These tabs 4 are oriented tangentially to the base 8, all in the same direction of rotation.

[0094] This piston 1 has a hollow upper face 22 in the shape of a truncated cone, to accommodate a purge ring (not shown) mounted on the end of a pump (not shown).

[0095] This piston 1 consists of a single part, obtained by bi-injection, or tri-injection.

[0096] THE ninth embodiment of the piston 1 according to the invention, shown in Figures 10a to 10b , is close to the eighth embodiment of the Figure 9 .

[0097] Piston 1 also has a circular section.

[0098] The piston 1 comprises a cylindrical base 8 having an upper circumference 21 from which the guide tabs 4 extend. In this case, there are seven guide tabs 4. These tabs 4 are oriented tangentially to the base 8, all in the same direction of rotation.

[0099] This piston 1 has a hollow upper face 22 in the shape of a truncated cone, to accommodate a purge ring (not shown) mounted on the end of a pump (not shown).

[0100] This ninth mode differs from the eighth mode in that the sealing means 2 consist of a flexible skirt 30 mounted tightly in the tank. The end of this skirt 30 forms a sealing lip capable of being pressed against the inner wall of the tank.

[0101] The sealing means 2 thus have a geometry which gives them increased flexibility compared to the sealing means 2 of the eighth embodiment. It is thus possible to produce these sealing means 2, as well as the rest of the piston 1, from polyethylene (PE). Thus, this piston 1 is made of a single material and produced by mono-injection. This geometry including the flexible skirt 30 thus makes it possible to simplify the injection process compared to the other embodiments while maintaining good performance in terms of sealing and guidance.

[0102] In the tenth embodiment of the piston 1 according to the invention, shown in Figures 11a to 11e , piston 1 is made in a modular manner.

[0103] First, a mold produces a strip of guide tabs 4, which extend from a base 24, for example of square, rectangular, or circular section, as can be seen in Figure 11a. Preferably, these legs 4 are connected to each other by a breakable link.

[0104] Furthermore, a piston 1 having the shape of a circular disc (or a square or other shape) acting as a base 8, is provided with housings 17 capable of receiving the bases 24 of the guide tabs 4, as shown in Figure 11b .

[0105] The bases 24 of the legs 4 are force-fitted or snapped into the housings 17.

[0106] This modular embodiment makes it possible 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 lugs 4.

[0107] 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 an average perimeter and is equipped with seven legs 4. Finally, on the Figure 11e, the piston 1 has a large perimeter and is equipped with nine legs 4.

[0108] In the eleventh embodiment of the piston 1 according to the invention, shown in Figures 12a And 12b , the piston 1 comprises retractable, foldable or flexible guide means 3.

[0109] In order to improve the product restitution rate, on the one hand by saving on the production of a complementary female shape of the guide means 3 on the pump mounting ring 15 or on the product reservoir 10, and on the other hand by maintaining a sufficient axial extension of the guide means 3 for effective guidance, it is possible to provide flexible or hinged tabs 4, capable of folding when they come into contact with the top 13 of the reservoir 10. Another advantage is that, since the stroke of the piston 1 is greater than with non-deformable rods, the surface area of the reservoir 10 available to cosmeticians for display is increased.

[0110] In embodiments 1 to 11, it would also be possible to return the piston 1 within the reservoir 10, that is to say to ensure that the guide means 3 are oriented towards the bottom 12 of the reservoir 10. In this case, the guide means 3 are not in contact with the fluid product contained in the reservoir 10. Only the base 8 and the sealing bead 2 are in contact with the fluid product.

[0111] In this case, the base 8 is closed with a surface oriented in the same plane as the flange, so as to obtain a uniform platform on which the fluid product is deposited. Instead of providing a relatively complicated complementary female shape, it will just be necessary to close the top 13 of the reservoir 10 with a flat surface against which the platform of the piston 1 will come into contact, in order to obtain a flat contact between the two surfaces and to ensure that all of the fluid is distributed through the outlet orifice of the reservoir 10.

[0112] THE twelfth embodiment of the piston 1 according to the invention, shown in Figures 13a to 13c , is close to the ninth embodiment of the Figures 10a And 10b .

[0113] Piston 1 has a circular section.

[0114] The piston has a cylindrical base 8, corresponding to a crown. 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.

[0115] The central part 26 of the crown is solid, and bowl-shaped, that is to say concave in appearance, 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 perfectly with the piston 1 at the end of dispensing (that is to say in the high position of the piston), so as to offer a maximum restitution rate of the product. Indeed, when the shapes are complementary, there is no product trapped in the high position of the piston, as shown in Figure 13c In this case, the piston 1 comes into contact with the purge ring 11.

[0116] The sealing means 2 consist of a flexible disc 2 whose periphery is curved in a direction opposite to the legs, said periphery forming a sealing lip 25.

[0117] The base 8 is mounted on said disc 2. The base 8 and the disc 2 each have a central part of concave appearance, the central part 27 of said disc 2 following the profile of the central part 26 of the base 8.

[0118] In this twelfth embodiment of the piston, the central part 26 of the base 8 is located below the sealing line formed by the sealing lip 25. This central part 26 is therefore clearly visible through the reservoir 10. In addition, this central part 26 increases the total height of the bottle accordingly. As the piston 1 is larger, it takes up space normally dedicated to cosmetic products. It is therefore necessary to increase the size of the reservoir 10 to accommodate the quantity of cosmetic product initially planned.

[0119] THE thirteenth embodiment of the piston 1 according to the invention, shown in Figures 14a to 14c , is close to the twelfth embodiment, and makes it possible to overcome the disadvantage of the bulky piston.

[0120] Piston 1 has a circular section.

[0121] The piston 1 has a cylindrical base 8, corresponding to a crown. The guide lugs 4 extend from the outer surface of the crown. These lugs 4 are oriented tangentially to the base 8, all in the same direction of rotation.

[0122] The central part of the crown is empty. More precisely, the crown defines a central recess.

[0123] The sealing means 2 consist of a flexible disc 2 whose periphery is curved in a direction opposite to the legs, said periphery forming a sealing lip 25. The base 8 is mounted on said disc 2.

[0124] This disc 2 has a central part 27 of convex appearance, penetrating inside the central recess of the base 8. This central part 27 corresponds to a dome 27. This flexible dome 27 is thus located in the center of the rigid base 8. The dome 27 is thus hidden inside the base 8, and is not visible from the outside of the reservoir 10. The piston 1 is thus significantly less voluminous than in the previous embodiment. This is notably shown in Figures 14a And 14b .

[0125] This central part 27 of the disc 2 is sufficiently flexible to be able to be inverted under the effect of a force applied to the top of the dome. In this case, the central part 27 takes on a concave shape, like that of the twelfth embodiment. Generally, 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 disc 2. Thus, when approaching the high position of the piston 1, the dome 27 comes into contact with the purge ring 11 and gradually turns over to adopt an inverted curvature at the end of the piston's movement, which makes it possible to obtain a complementarity of the shapes of the piston 1 and the purge ring 11, to maximize the product restitution rate. The inverted dome is shown in the Figure 14c .

[0126] 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 tank 10. This lip is curved, which gives it greater flexibility and allows it to absorb the difference between the lower and upper diameters of the tank 10. Indeed, the tank 10 is a molded part and has an internal draft necessary for demolding the part. There may therefore be dimensional differences within the tank 10.

[0127] In addition, the curved shape of the sealing portion is less visible than a shape with sharp edges, in that it diffracts less light. Therefore, the sealing lip is very discreet through the tank 10.

[0128] Preferably, in 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 Figures 13b And 14b This bottom could also be overmolded with the tank body or simply be integral with the tank body.

[0129] This bottom 12 has a shape complementary to the piston 1 in order to support the underside of the sealing lip, so as to withstand a vacuum leak test or the leakage of a product which tends 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 enclosure, intended to simulate for example the pressure conditions in the baggage holds of aircraft which are generally at low pressure, and a possible leakage of product is detected during the test. The vacuum is transmitted to the piston through an orifice at the bottom of the bottle.

[0130] In the prior art, the follower pistons of airless systems generally consist of two lips placed one above the other and at a distance from each other. Since 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 the vacuum. The vacuum is communicated to the space between the two lips. The upper lip, unlike the lower lip, presses firmly against the wall, thus preventing product leakage.

[0131] The piston 1 according to the invention has only one lip, similar to the lower lip of the prior art, which moreover has a curvature which promotes its opening during the test, and which therefore does not benefit from the beneficial effect of the upper lip in terms of resistance to leakage under vacuum conditions.

[0132] To remedy this, the bottom 12 of the bottle includes a peripheral groove 28 in which the piston lip is housed and prevents it from deforming and losing contact with the wall of the reservoir in the event of depression.

[0133] Preferably, in all embodiments, the piston 1 is made of a material having microbiocidal properties.

[0134] The microbiocidal properties of the material can be obtained by diffusion into the product of an antimicrobial agent, for example on an organic basis such as Trichlosan (trade name of Melcoplast) or on a silver basis, or even a mineral basis. In particular, the material can comprise at least one polyolefin, for example polyethylene, polypropylene and / or polystyrene, which is loaded with at least one antimicrobial agent.

[0135] 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 loaded with such metallic particles or having undergone a surface treatment by fluorination, zinc plating or copper plating.

[0136] The microbiocidal properties of the material can also be obtained by irradiating the piston with radiation of a suitable wavelength, in particular by means of a material which exhibits photoluminescence properties after exposure to external light. In particular, the material can be based on at least one polyolefin loaded with at least one additive capable of emitting photoluminescent radiation which has a wavelength of between 250 and 260 nanometers, and in particular 254 nanometers, which corresponds to the order of magnitude of sterilizing ultraviolet radiation.

[0137] With respect to the above description, the optimum dimensional relationships for the parts of the invention, including variations in size, materials, shapes, function and modes of operation, assembly and use, are believed to be apparent and obvious to those skilled in the art, and all relationships equivalent to those illustrated in the drawings and described in the specification are intended to be included in the present invention.

Claims

1. Piston (1) for a reservoir (10) of a dispenser of a fluid product without air intake, having a central axis X and comprising: - sealing means (2); - guide means (3); said sealing means (2) extending in a plane orthogonal to the axis X and defining a single external sealing line in a closed loop, distal to the axis X, capable of coming into contact with an inner wall (14) of the reservoir (10), said guide means (3) comprising a base (8) from which extend a plurality of tabs (4) having free ends (6) defining external guide points, distal to the axis X, capable of coming into contact with the inner wall (14) of the reservoir (10), said piston being characterized in that the sealing means (2) consist of a flexible disc (27) whose periphery is curved in a direction opposite to the tabs, said periphery forming a sealing lip (25) and in thatsaid base (8) comprises a solid central part (26), mounted on said disc, the base (8) and the disc each having a central part of concave appearance, the central part (27) of said disc following the profile of the central part (26) of the base (8).

2. Piston (1) according to the preceding claim, characterized in that said sealing means (2) develop around said base (8).

3. Piston (1) according to one of the preceding claims, characterized in that it has at least three legs (4).

4. Piston (1) according to the preceding claim, characterized in that said legs (4) are oriented tangentially to the base (8), all in the same direction of rotation.

5. Piston (1) according to one of the preceding claims, characterized in thatthe 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 SEBS, or very low density PE, or polyurethane type.

6. Piston (1) according to one of the preceding claims, characterized in that it consists of a single part obtained by injection of one or more materials.

7. Piston (1) according to one of the preceding claims, characterized in that the free end (6) of the legs (4) has a rounded shape.

8. Piston (1) according to one of the preceding claims, characterized in that It is designed in an intrinsically colored material.

9. Piston (1) according to one of the preceding claims, characterized in that It is made of a material with microbiocidal properties.

10. Fluid product dispenser without air intake comprising a reservoir (10) capable of storing the fluid product and housing a piston (1) as described according to 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 contact line, and the free ends (6) of the legs (4) being in contact with the inner wall (14) of the reservoir (10) forming contact points.

11. Distributor according to the preceding claim, characterized in that the piston (1) moves in the reservoir (10) between a lower position proximal to the bottom (12) of the reservoir (10) and an upper position proximal to the neck (13) of the reservoir (10), the distributor having a complementary shape (11) to the piston (1) in the vicinity of the neck (13) of the reservoir (10).

12. Dispenser according to claim 11, characterized in that it comprises a purge ring (11) with said complementary shape (11).

13. Dispenser according to claim 12, characterized in that said purge ring (11) fits with the piston (1) at the end of distribution.

14. Dispenser according to one of claims 10 to 13, characterized in that the bottom (12) of the tank (10) has a peripheral groove (28) in which said sealing lip (25) is housed.

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