Container head for a cosmetic product packaging device, device and associated assembly method

Abstract

Container head for a cosmetic product packaging device, device and associated assembly method. The head comprises a neck (22) having a sleeve (30) defining an external surface (38) and a helical thread (34) projecting radially from the external surface (38). It includes a closure member (24) comprising at least one complementary helical thread (72). The neck (22) defines an engagement region (40) for the closure member (24), in which the complementary helical thread (72) engages with the helical thread (34), leaving a non-zero clearance with the external surface (38). The neck (22) defines an intermediate transition region (42) and an alignment and clamping region (44) with a transverse extent greater than the engagement region (40).In the configuration mounted on the collar (22), at least one complementary helical thread (72) is arranged in radial interference with the external surface (38) in the alignment and clamping region (44). Figure for the abbreviation: Figure 3.

Description

Title of the invention: Container head for a cosmetic product packaging device, device and associated assembly method

[0001] The present invention relates to a container head for a cosmetic product packaging device, comprising:

[0002] - a collar comprising a sleeve defining an axial passage with a central axis and a external surface, the sleeve comprising at least one helical thread projecting radially from the external surface;

[0003] - a closing element, configured to move from a disassembled configuration to the gap of the neck to a configuration mounted on the neck, the closing member comprising at least one complementary helical thread intended to cooperate with the neck, the neck defining an engagement region of the closing member, in which the at least one complementary helical thread engages on the at least one helical thread leaving a non-zero clearance with the external surface of the neck.

[0004] The cosmetic product is, for example, a hair product, a hygiene product, a face and / or body care product, a makeup product, or a sun protection product.

[0005] More generally, a cosmetic product is a product as defined in Regulation (EC) No 1223 / 2009 of the European Parliament and of the Council of 30 November 2009 on cosmetic products.

[0006] The development of environmentally friendly packaging devices, that is, devices whose design and development take environmental issues into account, is becoming a major concern in order to help meet global challenges. It is therefore essential to offer more sustainable packaging devices that can address these environmental challenges.

[0007] In this context, it is important to develop packaging devices that promote the use of renewable raw materials, with a better carbon footprint, and / or with a good naturalness index and / or of natural origin and more particularly of plant origin.

[0008] This is particularly the case when reducing the amount of plastic material used for the production of a cosmetic product packaging device, resulting in a reduction in the wall thicknesses of the packaging device, particularly at the neck of the container holding the cosmetic product.

[0009] Alternatively, to produce the packaging device, it is possible to replace the plastic material with a cellulosic material, examples of which are described for example in FR3139556. Such a packaging device has a reduced environmental impact.

[0010] However, reducing the amount of plastic material, or replacing plastic material with cellulosic material, does not give complete satisfaction in some cases.

[0011] In particular, screwing the closing member onto the neck of the container generates cooperation between the thread of the neck and the complementary thread of the closing member, especially at the end of the screwing stroke.

[0012] This cooperation occurs away from the external surface of the neck, generally referred to as the "root of the thread". The thread(s) of the neck are thus subjected to bending stress by the complementary thread(s) of the closing element.

[0013] In the case of a collar of reduced thickness and / or made of cellulosic material, the flexural strength of the collar thread(s) is sometimes insufficient to prevent substantial deformation of the collar thread(s) during tightening.

[0014] In particular, for containers made of cellulosic material, the manufacturing process of the container neck results in the cellulosic fibers being less densely agglomerated at the neck's ribs, which are located in a hollow part of the container's forming support. Conversely, the fibers are more densely agglomerated in the tubular portion of the neck, which is in direct contact with the surface that retains the cellulosic fibers on the forming support and which is subjected to a greater compressive force during the container's formation or drying.

[0015] When tightening the closure device onto the bottle neck, the threads of the neck are sometimes insufficiently strong, causing, in some cases, a misalignment of the closure device with respect to the neck. This risk exists from the first time the neck is sealed by the closure device after the container has been filled with cosmetic product, and also after multiple opening / closing operations of the neck by the closure device by a user.

[0016] This generally leads to the axis of the closing element becoming misaligned and forming an angle with the axis of the neck. A leak may then occur between the neck and the closing element.

[0017] In this case, the product may leak or be contaminated by external pollutants. Furthermore, the aesthetic appearance of the packaging device is altered, which may lead the user to not buy it or to discard it prematurely.

[0018] Furthermore, in the case of a container associated with a closure element adapted to secure a dispensing pump to the neck of the container, with such Misalignment between the axis of the closure mechanism and the axis of the container neck results in the force exerted by a user on the pump's actuation mechanism being angled relative to the bottle neck axis. This imposes a localized compressive force on a portion of the neck, rather than distributing it across the entire structure. This localized stress concentration can exceed the strength of the neck material and lead to degradation of both the pump and the container.

[0019] US4798303 describes a collar on which a cap can be mounted, the collar having a general truncated conical shape. Similarly, EP2010435 describes a bottle neck of constant outside diameter, provided with a conical thread whose diameter increases towards the bottom of the bottle, on which a stopper is mounted.

[0020] In these two packaging devices, the cap is held in place on the neck by direct cooperation between the threads of the neck and those of the cap, in particular by a bending stress between these threads. These packaging devices are therefore not suitable for a substantial reduction in neck thickness and / or for replacing the plastic material with a cellulosic material.

[0021] An object of the invention is to have a container head having a neck and a closure member screwed onto the neck, the head having a reduced environmental impact, for example due to the nature of the material which constitutes it, and / or thanks to a reduced mass of material used to form it, while ensuring proper positioning and tightening of the closure member on the neck, on first use and even after several uses.

[0022] For this purpose, the invention relates to a container head of the aforementioned type, characterized in that the neck defines an intermediate transition region, and an alignment and clamping region, with a transverse extent greater than the engagement region, and in that, in the configuration mounted on the neck, at least one complementary helical thread is arranged in radial interference with the external surface, in particular at the axial distance from at least one helical thread, in the alignment and clamping region.

[0023] The complementary thread on the closing member being in interference in the radial direction, perpendicular to the central axis, with the external surface in the alignment and clamping region, in particular at the gap in the axial direction of the or each helical thread present on the neck, a more robust mechanical contact occurs between the or each complementary helical thread present on the closing member and a robust region of the neck, constituted by a thread root.

[0024] Thus, in the alignment and clamping region of the neck, an interaction occurs by mechanical interference in the radial direction between the complementary helical thread(s) of the closing member and the thread root on the outer surface of the neck. This produces a robust and repeatable clamping between the neck of the container and the closing element in the assembled configuration.

[0025] Furthermore, the bending stress on the neck thread(s) caused by the complementary helical thread(s) of the closure member is reduced, thus limiting their deformation. Indeed, in the configuration where the closure member is mounted on the container neck, the neck thread(s) are essentially subjected to shear stress by the complementary helical thread(s) of the closure member. Since the shear strength of the neck thread(s) is greater than the bending strength of the neck thread(s), these threads are therefore less deformed by the complementary helical thread(s) of the closure member when it is moved from the disassembled position away from the neck to the mounted position on the neck. The alignment of the axis of the closure member with the axis of the neck is maintained during the initial tightening and even after several uses.Furthermore, the robust clamping resulting from the interaction enhances the seal.

[0026] This ensures good preservation of the product contained in the tank, no leakage, and a satisfactory aesthetic appearance.

[0027] According to variants:

[0028] - at least one complementary helical thread is in radial interference with the external surface in the alignment and clamping region over at least 180° around the central axis, preferably over at least 270° around the central axis, or even more advantageously over at least 360° around the central axis;

[0029] - at least one complementary helical thread extends over at least 720° around the central axis and / or in which at least one helical thread extends over at least 720° around the central axis.

[0030] The radial interference over at least 180°, preferably over at least 270° of the or each complementary thread of the closing member with the external surface of the neck in the alignment and clamping region, reinforces the robustness of the connection between the closing member and the neck in the mounted configuration of the closing member and further limits the risk of angular misalignment by the significant cooperation between the complementary thread and the thread base on which it rests.

[0031] This is particularly the case when the net on the neck extends over at least two turns, that is to say over at least 720°, around the central axis.

[0032] According to one variant, the at least one complementary helical thread comprises an internal end surface disposed in support in the radial direction on the external surface, in particular at the axial distance from the at least one helical thread, in the alignment and clamping region.

[0033] The presence on the or each complementary helical thread of an internal end surface ensures support over a significant area of ​​the helical thread complementary on the external surface of the neck, in the alignment and clamping region, which further strengthens the clamping cooperation in the radial direction of the or each complementary helical thread with the external surface.

[0034] According to variants:

[0035] - at least one complementary helical thread is engaged under at least one thread helical in the engagement region;

[0036] - at least one complementary helical thread has an end surface internally arranged radially away from the external surface in the engagement region;

[0037] - the engagement of at least one complementary helical thread with at least one helical thread in the engagement region is carried out over at least 180° around the central axis, preferably over at least 270° around the central axis.

[0038] The presence of a complementary helical thread engaged under the helical thread in the engagement region on the neck ensures a simple and non-interfering engagement of the closing member on the neck and a progressive guidance of the closing member in rotation towards the alignment and clamping region.

[0039] Thus, the user's perception of the engagement of the closure element on the neck is initially identical to that which occurs on a conventional container head. This allows the user to adjust the tightening force of the closure element to prevent it from being excessive.

[0040] Such an effect is obtained particularly when the internal end surface of the complementary helical thread is arranged radially away from the external surface in the region of engagement on the body, and when the engagement of the or each complementary helical thread with the or each helical thread on the neck is preferably obtained over a cumulative angular extent of at least 270°.

[0041] According to variants:

[0042] - the intermediate region comprises an external frustoconical surface;

[0043] - the half-angle at the apex of a cone in which the intermediate region is inscribed is between 15° and 60°, preferably between 20° and 30°, and for example close to 27°.

[0044] The presence of an intermediate region having a frustoconical external surface ensures a progressive transition during the tightening of the closing member between the engagement of the closing member on the neck and its effective tightening by cooperation of the or each complementary thread with the external surface of the neck between the threads.

[0045] This transition is particularly gradual when the angle at the apex of the cone of the intermediate frustoconical region is within the aforementioned range.

[0046] According to one variant, the neck and / or the closing element is made from cellulosic material and / or is made by extrusion blow molding or by injection blow molding of plastic material.

[0047] Thanks to the effective tightening provided by the complementary helical thread in radial contact with the external surface, particularly away from the helical thread, it is possible to make the neck and / or the closing element from cellulosic material or by plastic blow molding processes by greatly reducing the wall thickness, particularly at the neck.

[0048] Thus, the head is made lighter in plastic material or is made from a material not containing plastic, while being reliably and securely usable several times by a user.

[0049] In one variant, the closing member is a capsule comprising a mechanism for dispensing product out of the container, or is a stopper for sealing the container.

[0050] Securing the closure element to the neck by screwing with radial interference between the complementary helical thread(s) and the thread root on the neck is particularly applicable to a cap incorporating a product dispensing system, since the cap is held robustly on the neck, allowing reliable and efficient operation of the product dispensing system. This fastening method is also applicable to a stopper, ensuring a tight seal even after repeated screwing and unscrewing.

[0051] In one embodiment, the sleeve has a transversely extending upper free edge, the head comprising an annular sealing gasket interposed between the free edge of the sleeve and the closing member.

[0052] The effective cooperation between the neck and the closing member makes it possible to interpose a flat seal on the upper free edge of the sleeve constituting the neck, in order to further increase the sealing at the neck.

[0053] In one variant, the external surface of the neck defines a thread root between successive turns of at least one helical thread, the at least one complementary helical thread being arranged in radial interference on the thread root in the alignment and clamping region, in the configuration mounted on the neck, the at least one complementary helical thread being arranged radially away from the thread root in the engagement region, in the configuration mounted on the neck.

[0054] The radial interference of the complementary helical thread with the thread base is particularly advantageous, since the thread base is a mechanically robust area which ensures solid support for the complementary helical thread, particularly in the case where the helical thread is made of cellulosic material or blown plastic material.

[0055] The invention also relates to a cosmetic product packaging device comprising a container delimiting an internal volume containing cosmetic product, and a head as defined above, protruding from the container.

[0056] The invention also relates to a method for mounting a container head comprising the following steps:

[0057] - supplying a head as defined above, the closing member being in its configuration unscrewed;

[0058] - engagement of the closing member on the engagement region of the member closure, the at least one complementary helical thread engaging on the at least one helical thread leaving a non-zero clearance with the external surface of the neck;

[0059] - engagement of at least one complementary helical net around the region alignment and tightening, at least one complementary helical thread being placed in radial interference with the external surface, in particular at an axial distance from at least one helical thread.

[0060] The invention will be better understood upon reading the following description, given solely by way of example, and made with reference to the attached drawings, on which: - [Fig.1] the [Fig.1] is a cross-sectional view along a median vertical plane of a first cosmetic product conditioning and distribution device having a container head according to the invention; - [Fig.2] [Fig.2] is an enlarged cross-sectional view along the vertical plane median of the neck of the container head of the [Fig.l], the neck defining from top to bottom a region of engagement of a closing member, an intermediate region and a region of alignment and tightening of the closing member; - [Fig.3] [Fig.3] is a view identical to [Fig.2], the closing mechanism having climbed onto the pass; - [Fig.4] [Fig.4] is a view analogous to [Fig.3] of a variant of conditioning and distribution device according to the invention.

[0061] In all that follows, the terms "upstream" and "downstream" are generally understood in relation to the normal direction of flow of a cosmetic product during its distribution.

[0062] A first device 10 for conditioning and distributing cosmetic product according to the invention is illustrated by [Fig.1].

[0063] The first device 10 is intended for the packaging and advantageously the dispensing of a liquid cosmetic product. The cosmetic product is, for example, a hair product, a hygiene product, a facial and / or body care product, a makeup product, or a sunscreen product. The cosmetic product is, in particular, a liquid, a gel, or a cream.

[0064] The device 10 comprises a cosmetic product container 12 and a closing and dispensing head 14 disposed here at an upper end of the container 12 along an elevation axis, or central axis, AA' of the container 12.

[0065] The container 12 comprises a base 16 and a side wall 18 which delimits an internal volume 20 intended to contain cosmetic product. The internal volume 20 is configured to contain, for example, between 5 ml and 500 ml, in particular between 15 ml and 100 ml of cosmetic product.

[0066] The head 14 includes a neck 22 fixedly mounted at a downstream end of the container 12 or coming from the material with the container 12. It includes a closing member 24 which is here screwed onto the neck 22 to be movable between a disassembled configuration of the neck 22 (not shown) and a configuration mounted on the neck 22, engaged with the neck.

[0067] In this example, the head 14 further includes a seal 26 which is interposed between the closing member 24 and the neck 22 to achieve a seal between these elements.

[0068] Advantageously, at least a part of the container 12, the neck 22 and / or the closure member 24 is made of cellulosic material, in particular at least a contact region between the neck 22 and the closure member 24.

[0069] The object made of cellulosic material, here at least a part of the container 12, the neck 22 and / or the closure element 24, is mainly composed of cellulosic fibers arranged in a three-dimensional structure. These cellulosic fibers may come from paper pulp produced from wood or plant fibers.

[0070] The cellulosic material thus includes, for example, paper fiber, cardboard fiber, wood fiber, or plant fiber, or paper pulp, or cardboard pulp, or a mixture of these materials.

[0071] The use of these materials has the advantage of being derived from renewable resources, thus reducing the use of raw materials from the petrochemical industry. These materials can be recycled through dedicated paper and cardboard recycling channels. In certain advantageous cases, they can also benefit from the biodegradability of cellulosic fibers. Therefore, the use of these materials improves the recyclability and / or degradability of the device, and these materials can also be advantageously sourced from recycling channels.

[0072] Cellulosic fibers can come, for example, from trees (for example, from softwood fibers, such as pine, fir or spruce, or from hardwood fibers, such as birch, beech, poplar, aspen, acacia or eucalyptus), from plants, such as bamboo, flax, hemp, or from agricultural by-products, such as bagasse, the fibrous residue of sugar cane, wheat straw, rice straw, corn stalks or a mixture of these materials.

[0073] The object made of cellulosic material is, for example, provided with a coating of another nature applied to its inner surface and / or its outer surface. This The coating's function is to protect the fibers and improve the surface properties of the object made from those fibers.

[0074] The materials used for the coating are generally layers, varnishes, resins which can be organic (Polyethylene - PE, Polypropylene - PP, Polyethylene terephthalate - PET, acrylics or acrylic derivatives, latex, Polyhydroxyalkanoate - PHA, Polylactic acid - PLA, waxes, paraffins derived from algae or starch) or inorganic (aluminum oxide, silicon oxide for example) and deposited in thicknesses ranging from a few nanometers to several hundred microns.

[0075] Alternatively, the material forming the container 12, the neck 22 and / or the head 24 is at least partially made of plastic, but with a reduced wall thickness, in particular at the neck 22, for example less than 0.5 mm.

[0076] In predefined regions, the container 12, the neck 22 and / or the head 24 are, for example, produced by injection blow molding or extrusion blow molding. This leads to a natural reduction in wall thickness in these certain regions, which can be approximately 30% in some cases.

[0077] With reference to [Fig.2], the neck 22 includes a sleeve 30 defining an internal passage 32 with axis AA' opening into the internal volume 20. The neck 22 includes, in radial projection of the sleeve 30, at least one helical thread 34 intended for screwing the closing member 24 onto the neck 22.

[0078] The passage 32 is defined by an internal surface 36 of the sleeve 30. The sleeve 30 also defines an external surface 38, from which the helical thread 34 protrudes.

[0079] According to the invention, the sleeve 30 comprises, from the outside in, from top to bottom on the [Fig.2], a downstream engagement region 40 of the closing member 24, substantially cylindrical, an intermediate frustoconical region 42, and an upstream alignment and clamping region 44 of the closing member 24, also substantially cylindrical.

[0080] The external surface 38 extends in this example to a first maximum radial distance DI from the central axis AA' in the engagement region 40, away from the helical thread 34.

[0081] The intermediate region 42 is generally frustoconical in shape; the half-angle at the apex of the cone in which the external surface 38 is inscribed in the intermediate region 42 is, for example, less than 60°, in particular between 15° and 60°, better between 25° and 30°, and for example close to 27°. It is recalled here that the half-angle at the apex of a cone corresponds to the angle formed between the generatrix of this cone and the central axis of the cone, constituted in this case by the central axis A-A'.

[0082] The height of the intermediate region 42, taken along the axis A-A', is generally less than or equal to the height of the engagement region 40, taken along the axis A-A'.

[0083] The alignment and clamping region 44 is cylindrical in shape. The external surface 38 extends in this example to a second maximum radial distance D2 from the central axis AA' in the alignment and clamping region 44, away from the helical thread 34, the distance D2 being greater than the distance DI.

[0084] In this example, the neck 22 comprises a continuous helical thread 34. Alternatively (not shown), the neck 22 has a plurality of disjoint helical threads 34, extending helix-wise around the axis A-A'.

[0085] The helical thread 34 extends over at least 720° around the axis A-A'. Preferably, it extends over at least 270°, preferably over at least 360° in the engagement region 40, and over at least 270°, preferably over at least 360° in the alignment and clamping region 44.

[0086] In this example, the helical net 34 has, in cross-section along a median axial plane passing through the axis A-A', from downstream to upstream, a downstream frustoconical engagement surface 50, moving away from the axis AA' while moving upstream, an external circumferential end surface 52, and an upstream frustoconical retention surface 54, moving closer to the axis AA' while moving upstream.

[0087] The apex angle of a cone in which the downstream frustoconical surface 50 is inscribed is less than the apex angle of a cone in which the upstream frustoconical surface 54 is inscribed.

[0088] For example, the half-angle at the apex of the cone in which the downstream frustoconical surface 50 is inscribed is between 30° and 60° and the half-angle at the apex of the cone in which the upstream frustoconical surface 54 is inscribed is between 88° and 60°.

[0089] Alternatively, the helical thread 34 has, in cross-section along a median axial plane passing through the axis A-A', a rounded profile, such as in an arc of a circle.

[0090] In the example of [Fig.2], the circumferential end surface 52 is further away from the axis AA' in the intermediate region 42 and in the alignment and clamping region 44 than in the engagement region 40.

[0091] In this example, the internal surface 36 of the sleeve 30 delimits a shape substantially complementary to the helical thread 34 opposite the helical thread 34.

[0092] Thus, in the case of a neck 22 made of fibrous materials, the density of cellulosic fibers in the helical mesh 34, opposite the hollow 56, is less than the density of cellulosic fibers in the bottom of the mesh 58, defined on the external surface 38 away from the helical mesh 34.

[0093] With reference to [Fig. 3], the closing member 24 comprises a cylindrical skirt 70, intended to be inserted around the sleeve 30 of the neck 22 along the axis A-A', and at least a complementary helical thread 72, intended to engage with the helical thread 34, the complementary helical thread 72 projecting into the skirt 70 towards the axis A-A'.

[0094] The closing member 24 further comprises a transverse end wall 74 which, in this example, is annular.

[0095] In this example also, the closing member 24 carries a product distribution mechanism 76 comprising a pump 78 fixedly mounted between the seal 26 and the end wall 74, a push button 80 for actuating the pump 78 and distributing the product and optionally a dip tube 82, visible in [Fig.1].

[0096] The cylindrical skirt 70 defines an external surface 90 and an internal cylindrical surface 92 from which the complementary helical thread 72 protrudes.

[0097] The complementary helical thread 72 has a helical shape complementary to that of the or each helical thread 34. It has, in cross-section along a median axial plane passing through the axis A-A', an internal end surface 94, disposed between an upstream surface 96 and a downstream surface 98, the internal end surface 94 being intended to face the external surface 38 of the sleeve.

[0098] In this example, the radial clearance defined between the internal end surface 94 of the complementary helical thread 72 in the engagement region 40 with the external surface 38 is non-zero and positive, when the closing member 24 is screwed onto the neck 22.

[0099] In the engagement region 40, a gap 97 therefore exists in the radial direction between the external surface 38 away from the helical thread 34 and the internal end surface 94 of the complementary helical thread 72. Thus, during the initial engagement of the complementary helical thread 72 on the helical thread 34, the clamping force is reduced and corresponds to that to be applied for a conventional closing member.

[0100] In the engagement region 40, the downstream surface 98 engages under the upstream frustoconical surface 54 to provide guidance for the helical rotation of the closing member 24 on the neck 22 when screwing the closing member 24 onto the neck 22.

[0101] The helical thread 34 is subjected to bending by the contact between the upstream frustoconical surface 54 of the helical thread 34 and the downstream surface 98 of the complementary helical thread 72.

[0102] On the contrary, in the alignment and clamping region 44, the internal end surface 94 of the complementary helical thread 72 has zero or preferably negative radial clearance with the external surface 38 of the sleeve 30 in the thread root 58, away from the helical thread 34.

[0103] The complementary helical thread 72 is then in radial interference with the thread root 58 defined between the successive turns of the helical thread 34. An interaction in the radial direction therefore occurs between the complementary helical thread 72 and the external surface 38 in the thread root 58, in particular at the axially offset from the upstream frustoconical surface 54.

[0104] Advantageously, there is also contact between the base of the upstream frustoconical surface 54 of the helical net 34 with the downstream surface 98 of the or of each complementary helical net 72.

[0105] Thus, the most significant interference between the complementary helical thread 72 and the sleeve 30 occurs in the thread base 58. This is particularly beneficial in the case where the neck 22 is made of cellulosic material, the density of cellulosic fibers being maximum in the thread base 58, given its cylindrical geometry without hollows.

[0106] This results in a robust alignment and tightening of the closing member 24 on the neck 22, on the first screwing and even after several screwing / unscrewings of the closing member 24.

[0107] In this example, the product distribution mechanism 76 is engaged under the end wall 74, with the pump 78 protruding inside the passage 32.

[0108] The push button 80 protrudes axially outside the end wall 74 and is configured to be moved along the axis A-A' to cause the activation of the pump 78, and the aspiration of product through the dip tube 82, the pump 78 and at least one product distribution conduit 99 defined within the push button 80.

[0109] In this example, the sealing joint 26 comprises a flange 100, arranged to rest flat on the free edge 102 of the sleeve 30 and a cannula 104 protruding from an inner edge of the flange 100 to insert into the passage 32, in contact with the internal surface 36.

[0110] The flange 100 is thus arranged flat by being axially clamped on one side, by the free edge 102 of the neck 22 and on the other side, by the end wall 74 of the closing member 24, with possibly the interposition of the product distribution mechanism 76.

[0111] The assembly of the conditioning and distribution device 10 according to the invention will now be described.

[0112] Initially, the container 12 with its neck 22 is supplied. The container 12 and the neck have been previously manufactured, for example, from cellulosic material as defined above, or from plastic material, advantageously by an extrusion blow molding or injection blow molding process, with in particular a reduced wall thickness at the neck.

[0113] When a seal 26 is present, the seal 26 is first mounted on the neck 22, by applying the flange 100 to the free edge 102 of the sleeve 30.

[0114] The cannula 104, when present, is inserted into the passage 32, in contact with the internal surface 36 of the neck.

[0115] Alternatively, the seal 26 and the cannula 104 are advantageously carried by the closing member 24 and placed on the neck 22 of the container 12 when the closing member 24 is moved from the disassembled configuration to the assembled configuration.

[0116] Then, when the closing member 24 carries a product distribution mechanism 76, the dip tube 82 and the pump 78 are inserted through the passage 32. The cylindrical skirt 70 engages around the engagement region 40 of the neck 22.

[0117] During this movement, the complementary helical thread 72 of the cylindrical skirt 70 first comes into contact with the helical thread 34 of the neck 22 in the engagement region 40.

[0118] A non-zero radial clearance exists between the thread root 58 defined on the external surface 38 in the engagement region 40 and the internal end surface 94 of the complementary thread 72. As a result, the user can easily initiate the screwing of the cylindrical skirt 70 on the engagement region 40, with a force comparable to that of a conventional screwing over an angular path advantageously of at least 270°.

[0119] Then, the complementary helical thread 72 passes into the intermediate region 42 and reaches the alignment and clamping region 44.

[0120] The radial play between the internal end surface 94 of the complementary net 72 and the net base 58 gradually decreases and becomes zero or preferably negative.

[0121] The internal end surface 94 then applies itself against the bottom of the thread 58, under the upstream frustoconical surface 54 of the or of each helical thread 34.

[0122] Thus, the or each complementary helical thread 72 is in radial interference with the thread root 58 defined on the external surface 38 of the sleeve 30 away from the or each helical thread 34.

[0123] The complementary helical thread 72 therefore interacts directly with the external surface 38 of the neck 22, which reinforces the strength and robustness of the fastening of the closing member 24.

[0124] The helical thread 34 of the neck 22 is stressed essentially in shear by the complementary thread 72 of the closing member 24 in the alignment and clamping region 44 and thus opposes a resistance greater than that which it would oppose if it were stressed essentially in bending.

[0125] Indeed, the thread base 58 is more mechanically robust than the helical thread 34, for example because the wall thickness is greater in relation to the thread base 58 compared to the wall thickness in relation to the helical thread 34 in the case of a neck 22 made by blowing or because the density of cellulosic fibers at the level of the thread base 58 is greater than the density of cellulosic fibers at the level of the helical thread 34.

[0126] A precise and reproducible alignment of the axis of the closing member 24 with the axis of the neck 22 is thus obtained after screwing. In addition, the contact of the surface internal end 94 making on the thread base 58, the fixing is robust, even if the screwing is not a first screwing, and even after at least one unscrewing / screwing cycle.

[0127] The radial interference cooperation between the thread base 58 and the complementary helical thread 72 avoids the appearance of strong bending stresses between the helical thread or each helical thread 34 of the neck 22 and the complementary helical thread 72 of the closing member 24, which would be likely to substantially deform the helical thread or each helical thread 34 of the neck 22 in the alignment and clamping region 44.

[0128] Thus, the tightening is carried out efficiently, ensuring a strong seal between the closure member 24 and the neck 22. Since the shear strength of the helical thread 34 of the neck 22 is greater than its flexural strength, the risk of critical deformation of the helical thread 34 during tightening, and therefore of misalignment between the closure member and the neck of the container and / or of a leak, is significantly reduced. Material thinning is also reduced if the material is prone to creep.

[0129] In one variant, shown in [Fig.4], the outer end surface 52 of the helical thread or of each helical thread 34 in the alignment and clamping region 44 is disposed at a radial distance from the axis AA' substantially equal to the radial distance from the axis A-A' of the outer end surface 52 in the intermediate region 42 and / or substantially equal to the radial distance from the axis A-A' of the outer end surface 52 in the engagement region 40.

[0130] The external end surface 52 in the alignment and clamping region 44 is then a cylindrical surface over the entire periphery of the or each helical thread 34, advantageously over a height greater than the wall thickness.

[0131] In a variant of the heads 14 illustrated in figures 3 and 4, the closing member 24 is devoid of a product distribution mechanism 76. The end wall 74 is solid and the closing member 24 is a neck sealing plug 22.

Claims

Demands

1. A container head (14) for a cosmetic product packaging device (10), comprising: - a neck (22) including a sleeve (30) defining an axial passage (32) with central axis (A-A') and an external surface (38), the sleeve (30) including at least one helical thread (34) projecting radially from the external surface (38), - a closure member (24), configured to transition from a disassembled configuration away from the neck (22) to a configuration mounted on the neck (22), the closure member (24) including at least one complementary helical thread (72) intended to cooperate with the neck (22), the neck (22) defining an engagement region (40) of the closure member (24), in which the at least one complementary helical thread (72) engages with the at least one helical thread (34) leaving a clearance. null with the external surface (38) of the neck (22);characterized in that the collar (22) defines an intermediate transition region (42), and an alignment and clamping region (44), with a transverse extent greater than the engagement region (40), and in that, in the configuration mounted on the collar (22), at least one complementary helical thread (72) is arranged in radial interference with the external surface (38), in particular at an axial distance from at least one helical thread (34), in the alignment and clamping region (44).

2. Head (14) according to claim 1, wherein at least one complementary helical thread (72) is radially interfered with the external surface (38) in the alignment and clamping region (44) over at least 180° around the central axis (A-A'), preferably over at least 270° around the central axis (A-A'), or even more advantageously over at least 360° around the central axis (AA n

3. / X ). Head (14) according to claim 2, wherein at least one complementary helical thread (72) extends over at least 720° around the central axis (A-A') and / or wherein at least one helical thread (34) extends over at least 720° around the central axis (A-A').

4. Head (14) according to any one of claims 1 to 3, wherein at least one additional helical thread (72) includes an internal end surface (94) disposed to bear in the radial direction on the external surface (38), in particular at the axial distance of at least one helical thread (34), in the alignment and clamping region (44).

5. Head (14) according to any one of the preceding claims, wherein at least one complementary helical thread (72) is engaged under at least one helical thread (34) in the engagement region (40).

6. Head (14) according to claim 5, wherein at least one complementary helical thread (72) has an internal end surface (94) arranged radially away from the external surface (38) in the engagement region (40).

7. Head (14) according to any one of the preceding claims, wherein the engagement of at least one complementary helical thread (72) with at least one helical thread (34) in the engagement region (40) takes place over at least 180° around the central axis (A-A'), preferably over at least 270° around the central axis (A-A').

8. Head (14) according to any one of the preceding claims, wherein the intermediate region (42) comprises a frustoconical external surface (38).

9. Head (14) according to claim 8, wherein the half-angle at the apex of a cone in which the intermediate frustoconical region (42) is inscribed is between 15° and 60°, preferably between 20° and 30°, and for example close to 27°.

10. Head (14) according to any one of the preceding claims, wherein the neck (22) and / or the closing member (24) is made from cellulosic material and / or is made by extrusion blow molding or by injection blow molding of plastic material.

11. Head (14) according to any one of the preceding claims, wherein the closing member (24) is a capsule comprising a product dispensing mechanism (76) out of the container (12), or is a sealing cap for the container (12).

12. Head (14) according to any one of the preceding claims, wherein the sleeve (30) has a transversely extending upper free edge (102), the head (14) comprising an annular sealing gasket (26) interposed between the free edge (102) of the sleeve (30) and the closing member (24).

13. Head (14) according to any one of the preceding claims, wherein the external surface (38) of the neck (22) defines a thread root (58) between successive turns of at least one helical thread (34), the at least one complementary helical thread (72) being arranged in radial interference on the thread root (58) in the alignment and clamping region (44), in the configuration mounted on the neck (22), the at least one complementary helical thread (72) being arranged radially away from the thread root (58) in the engagement region (40), in the configuration mounted on the neck (22).

14. Cosmetic product packaging device (10) comprising a container (12) delimiting an internal volume (20) containing cosmetic product, and a head (14) according to any one of the preceding claims, projecting from the container (12).

15. Method of mounting a head (14) of a container (12), comprising the following steps: - supplying a head (14) according to any one of claims 1 to 13, the closing member (24) being in its unscrewed configuration; - engaging the closing member (24) on the engagement region (40) of the closing member (24), the at least one complementary helical thread (72) engaging on the at least one helical thread (34) leaving a non-zero clearance with the external surface (38) of the neck (22); - engaging the at least one complementary helical thread (72) around the alignment and clamping region (44), the at least one complementary helical thread (72) being placed in radial interference with the external surface (38), in particular at the axial distance from the at least one helical thread (34).

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