Piston-stopper dispenser

Abstract

A dispenser for a liquid cosmetic product, includes a reservoir, an internal piston, and an applicator end piece provided with and end valve. The dispenser is characterised in that the reservoir is defined inside the end piece, at a first end, by the valve, and, at the other end, by the piston, the piston forming a stopper screwed onto a threaded axial rod fixed to a base which is rotatably connected to the end piece.

Description

FIELD OF THE INVENTION

This invention relates to a dispenser of liquid cosmetic products as well as to a method for packaging these products.

More specifically, the invention is applicable to products such as, particularly, creams, gels and semi-liquid viscous products, which are currently increasingly replacing traditional products in solid stick or paste form.

BACKGROUND OF THE INVENTION

There are known dispensers of the type that comprise particularly a reservoir, an internal piston and an applicator nozzle provided with an end valve.

For what relates, more specifically, to semi-liquid products, their density and high viscosity render these dispensers useless and make it necessary to modify their structure in order to meet stricter conditions of dosing, watertightness and protection of the product.

For marketing reasons, it is equally important to preserve at least part of the overall appearance of the traditional packaging in order to avoid an abrupt break with the make-up habits of the users.

In particular, it seems essential to perpetuate the use of a rotary movement for delivering and dosing the product.

And yet, due to the fluidity of certain products, resorting to such a movement poses watertightness and dosing problems.

It is necessary particularly to guarantee hermetic blocking of the dispenser using an end valve that does not have any kind of retention area in which a residual volume of the product would be at a risk of remaining and drying up, resulting in blocking the valve.

Furthermore, the packaging of liquid cosmetics poses specific problems relating particularly to the air contained in the reservoir, which must necessarily be evacuated during the filling phase of the dispenser.

This hydraulic constraint generally implies implementing complex means at the product manufacturer's plant, which result in parasitic technical difficulties and pointless additional costs.

SUMMARY OF THE INVENTION

The aim of this invention is to solve these problems in a satisfactory manner, by providing a dispenser with an original structure using the piston-plug concept.

This aim is achieved, according to the invention, by means of a dispenser characterised in that the said reservoir is delimited inside the nozzle, at a first end by the said valve and, at the other end, by the said piston forming a plug, which is screwed onto a threaded axial rod formed integral with a base connected rotatingly to the said nozzle.

According to an advantageous characteristic, the said piston comprises, on the one hand, a cylindrical compression element covering the said threaded rod and having a peripheral lip in watertight contact with the inside wall of the reservoir and, on the other hand, on the outside of the said reservoir, a connection collar attached to the said rod and rotatingly blocked on the said base.

According to an alternative embodiment of the invention, the said reservoir is provided with a jacket fixed in the nozzle extended, if required, by a sleeve housed in the base.

Preferably, the said sleeve is provided with means for blocking the rotation of the said piston and means for locking it in the base.

Another aim of the invention is a method for packaging a liquid cosmetic product in a dispenser of the type comprising, particularly, an applicator nozzle enclosing an internal piston and a reservoir blocked at a first end by a valve, characterised in that the reservoir is filled by its other end in the inverted position of the dispenser, and then the said piston is inserted as a plug, expelling the air in the reservoir to close off this other end in a watertight manner, and the piston is locked in this closed position.

According to an advantageous characteristic of the method, it provides for a threaded axial rod, formed integral with a base, to be inserted and fixed in the said piston, prior to closing the reservoir.

Furthermore, the fixing of the rod in the piston and transmission of the movement are provided by elastic distortion of the material from which the piston is made.

In addition, the piston is locked in the closed position of the reservoir by axially and rotatingly connecting the base to the nozzle.

In parallel, the rotation of the said piston is blocked by cooperation with limit stops formed integral with the nozzle.

Preferably, the watertightness of the reservoir is only ensured when locking the said piston.

Finally, the reservoir is filled leaving a small amount of air forming a buffer such as to prevent the product from leaking through the valve when inserting the piston.

Thus, the rotation movement of the base is transformed into an axial translation of the piston in the reservoir, which places the product under pressure and enables it to be delivered.

The dispenser of the invention has a general appearance and ergonomics that are very similar to those of traditional sticks while having very different functional elements that are adapted to the nature of new semi-liquid products, to their physical properties and to the small doses that need to be dispensed.

This dispenser can therefore have applications in the field of liquid cosmetics, packaged for sale or as samples.

In addition, the watertightness of the dispenser and the way in which the product is dispensed are perfectly compatible with the constraints that relate to liquid cosmetic products.

The dispenser of the invention also has a very simple structure and therefore a particularly inexpensive cost price.

Moreover, the packaging method of the invention is particularly easy to implement and its piston-plug principle provides watertight and reliable sealing of the dispenser, which overcomes the problems of air being included.

In fact, the air is released gradually during the blocking phase as the piston enters the reservoir.

In addition, there is no need to provide watertightness means at the bottom of the dispenser insofar as the piston-plug already provides this watertightness inside it, at the top.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood from reading the following description made in reference to the appended diagrams, in which:

FIG. 1 shows an axial section view of an embodiment of the dispenser of the invention.

FIGS. 2A to 2C show schematic views of various steps in the packaging method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The dispenser shown in FIG. 1 is designed for delivering and applying liquid cosmetic products.

For this purpose, it comprises an applicator nozzle 1 provided with an end valve 2, a product reservoir 10 and an internal piston 3.

The valve 2 is made up, for example, of an evacuation orifice 20 arranged on an elastically distortable portion of the wall of the nozzle 1, with its edges resting against a pin or needle valve 50 supported here, via a spacer 55, by a jacket 5 fixed in the said nozzle.

According to an alternative not shown in the figures, it is possible to add a lid to cover the nozzle 1, which can support the pin instead of the jacket, if required.

The reservoir 10 is delimited inside the nozzle 1, at a first end (top in this case) by the valve 2 and, at the other end (bottom in this case) by the piston 3 forming a plug, which is screwed onto a threaded axial rod 41 formed integral with a base 4 rotatingly connected to the nozzle 1.

The piston 3 comprises a cylindrical compression element 31 that covers the threaded rod 41 and has a peripheral lip 35 that is able to slide in watertight contact with the inside wall of the reservoir 10, in this case covered with the jacket 5.

This compression element 31 is connected, outside the reservoir, via a socket 33, to a connection collar 32 attached to the rod 41 and rotatingly blocked in the base 4 by means of limit stops formed integral with the nozzle 1, such as a series of axial ribs 42.

Preferably, as shown in the figures, the jacket 5 is extended by a sleeve 54 that is housed and axially locked in the base 4, for example using locking means 44 that allow the relative rotation of the latter.

The jacket 5 matches the inside profile of the nozzle 1 and has a widened section 53 for connection with the sleeve 54.

Rotating the base 4 in relation to the nozzle 1 results, by transmission of the movement via the thread and the limit stops 42, in ascending axial translation of the piston 3 inside the reservoir 10 and the necessary compression of the product, forcing the valve 2 to open and deliver the product.

The assembly of the various parts of the dispenser as well as the packaging of the product are carried out as follows, placing the nozzle in an inverted position as shown in FIGS. 2A to 2C.

First of all, the reservoir 10 is filled by the open end of the sleeve 54, the valve 2 remaining closed and providing the watertightness at the bottom as shown in FIG. 2A.

The filling of the reservoir stops when the level of the product P reaches, at maximum, the widened section 53 of the sleeve 5.

It is preferable, however, to leave a small amount of air above the level of the product in order to compensate for possible faults in the filling and/or in the positioning of the piston 3 and to avoid the risk of the product leaking out of the valve 2 when inserting the piston. This layout makes it possible to create a compressible area forming a buffer that is able to absorb the pushing effort of the piston and to minimise its effects on the uncompressible liquid product.

The base 4 is assembled on the piston 3, previously or on the packaging site, by forced insertion of the rod 41 in the collar 32 as shown in FIG. 2B.

If the collar is not provided with a thread, it must be made from a flexible, elastic material that allows it to distort in order to fix and anchor on the threads of the rod 41, which in turn is made from a rigid plastic material.

Then, the piston 3 is inserted in the jacket 5 as if it were a plug, pushing by the base 4 and expelling, via the lip 35 and around the socket 33, the air contained in the reservoir.

In the final phase of the assembly operations, the fraction of air that remains inside the reservoir, is expelled to the outside, under the increasing pressure created by the piston, passing through the gorge 34 made in the wall of the collar 32, getting round the edge of the sleeve 54 and then through the evacuation channel 40 made in the wall of the base 4 or, according to an alternative, through a groove (not shown) made in the outside wall of the sleeve 54 or in the inside wall of the base.

Therefore, only the lip 35 reaches the end, in watertight contact with the wall of the sleeve 5 at the height of the section 53.

Thus, the reservoir 10 is only sealed in a watertight manner during the final step, when the piston-plug 3 is locked in its blocking position by axially connecting the base 4 to the socket 54 of the nozzle.

The rotation of the piston 3 is also blocked at this point by cooperation of the collar 32 with the limit stops 42 formed integral with the socket 54 and thus with the nozzle 1.

In this position, the compression element 31 is almost in contact with the free surface of the liquid product P and, once returned to the position shown in FIG. 1, the dispenser is ready to be used.

The axial movement of the piston 3 in the reservoir, in the direction of the valve, causes compression inside the reservoir 10 and a depression in the compartment delimited between the base 4, the sleeve 54, the socket 33 and the collar 32. This depression is compensated by air being taken in through the channel 40 and the gorge 34.

Thus, the watertightness of the dispenser is only necessary at the level of the piston-plug, which thus forms, during operation, the bottom of the reservoir 10.

A tamper-proof strip placed between the nozzle and the base can advantageously complete the assembly while a lid (not shown) can, if required, round off the packaging and the aesthetic appearance of the whole dispenser.

Claims

1. A dispenser for liquid cosmetic products comprising a reservoir, an internal piston and an applicator nozzle provided with an end valve, characterised in that said reservoir is delimited inside the nozzle, at a first end, by said valve and, at the other end, by said piston forming a plug, which is screwed onto a threaded axial rod formed integral with a base rotatingly connected to said nozzle.

2. A dispenser according to claim 1, characterised in that said piston comprises, on the one hand, a cylindrical compression element covering said threaded rod and which has a peripheral lip in watertight contact with the inside wall of the reservoir and, on the other hand, on the outside of said reservoir, a connecting collar attached to said rod and rotatingly blocked in said base.

3. A dispenser according to claim 1, characterised in that said reservoir is provided with a jacket fixed in the nozzle which is extended, as required, by a sleeve housed in the base.

4. A dispenser according to claim 3, characterised in that said sleeve is provided with means for blocking the rotation of said piston and means for axial locking in the base.

5. A method for packaging a liquid cosmetic product in a dispenser of the type that comprises an applicator nozzle, enclosing an internal piston and a reservoir blocked at a first end by a valve, characterised in that the reservoir is filled by its other end, with the dispenser in its inverted position, and then the piston is inserted in the form of a plug, expelling the air contained in the reservoir in order to close off this other end in a watertight manner, and said piston is locked in this closed position.

6. A method according to claim 5, characterised in that, prior to closing the reservoir, an axial rod formed integral with a base is inserted and fixed in said piston.

7. A method according to claim 6, characterised in that the fixing of the rod in the piston and the transmission of the movement are provided by elastic distortion of the material from which the piston is made.

8. A method according to claim 5, characterised in that the piston is locked in the closed position of the reservoir by axially and rotatingly connecting the base to the nozzle.

9. A method according to claim 5, characterised in that said piston is rotatingly blocked by cooperation with limit stops formed integral with the nozzle.

10. A method according to claim 5, characterised in that the watertightness of the reservoir is only ensured during the step in which said piston is locked.

11. A method according to claim 5, characterised in that the reservoir is filled leaving a small amount of air inside it forming a buffer in order to avoid any leaks from the valve when inserting the piston.