Fluent material handling – with receiver or receiver coacting mea – Filling or refilling of dispensers – Aerosols
Reexamination Certificate
2000-03-23
2001-05-15
Douglas, Steven O. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Filling or refilling of dispensers
Aerosols
C141S003000, C222S321700, C222S386000
Reexamination Certificate
active
06230762
ABSTRACT:
The present invention relates to an assembly for packaging a product, particularly a cosmetic product, and dispensing it under pressure, of the type using a piston. The products which the present invention dispenses may be of liquid-to-pasty consistency. They may, for example, be a spray or a lacquer, particularly for hair styling, or a milk, or a gel, or a cream or a paste.
Pistons may be used in aerosol devices in which the product is pressurized by means of a propellant, for example a compressed or liquefied gas kept isolated from the product by the piston. Pistons may also be used in pump mechanisms which operate without an air intake, in which case the function of the piston is to follow the level of product inside the container so that, regardless of how much the device has been used, the product always occupies all the available volume.
In the field of aerosols, it is known to produce devices in the form of a container containing the product and having a free edge which delimits an opening in which a valve is mounted, a piston being mounted so as to move axially inside the container. The piston separates in leakproof fashion a first volume, adjacent to the dispensing member and containing the product, from a second volume adjacent to a bottom of the container and containing the propellant. The bottom of the container is closed and includes means, for example in the form of a valve or some other equivalent member, to allow the propellent gas to be introduced into the second volume. The container may for example be made of metal.
Dispensers fitted with an “airless pump” are commonly used in fields such as cosmetics. As used herein, the term “airless pump” refers to a pump that provides pumping of a substance from a container in essentially a single direction without permitting reverse (intake) flow of air via the pump. That is, as product is pumped from the container, the pumped product is not replaced with a corresponding volume of air through the pump. In addition to preventing reverse intake flow of “air” via the pump, an “airless pump” typically does not allow intake of any other substances to replace the volume of product pumped out of the container. For example, an “airless pump” could include a one-way valve, such as a check valve.
There are several problems associated with producing and using such devices. First of all, the leakproof seal achieved between the piston and the interior surface of the container, particularly in the case of metal containers, is often insufficient. This problem is all the more critical when the can, made of metal, has a longitudinal weld line which produces a thickening that is detrimental to forming a leakproof seal. Furthermore, the piston is molded in an auxiliary mold which has a serious adverse effect on the cost of manufacture of such a device. Finally, in the case of a container which narrows near its opening, it is necessary to introduce the piston into the container before the narrowing is formed, and this greatly complicates the manufacturing process.
In the case of an airless pump device, using a follower piston, there is the same problem of cost associated with the use of an auxiliary mold for producing the piston. There is also the problem associated with making the contact between the peripheral surface of the piston and the interior surface of the container leakproof.
Therefore, one of the objects of the present invention is to provide a dispenser for storing a product under pressure, for example a cosmetic product, and for dispensing it using a piston, which also completely or partially solves the problems discussed hereinabove with reference to the conventional devices.
A particular object of the invention is to provide a dispenser of the piston type which offers a better leakproof seal in comparison to conventional devices.
Another object of the invention is to provide a dispenser of the piston type which is less expensive to manufacture in comparison to conventional devices.
It should be understood that the invention could still be practiced without performing one or more of the preferred objects and/or advantages set forth above. Still other objects will become apparent after reading the following description of the invention.
To achieve these and other advantages, and in accordance with the purposes of the invention, as embodied and broadly described herein, the invention includes a dispenser. The dispenser comprises a container containing the product and having a free edge which delimits an opening in which is mounted a dispensing member. The dispensing member may preferably be a manually actuated pump or a valve. A piston is mounted so as to move axially inside the container and to separate in leakproof fashion a first volume, adjacent to the dispensing member and containing the product, from a second volume adjacent to the first, the piston being formed by molding directly inside the container.
As the piston is molded directly inside the container, it is possible to obtain a piston whose peripheral surface perfectly matches the profile formed by the interior surface of the container, and is thus leakproof, regardless of the manufacturing tolerances of the container. This improvement is most particularly marked in the case of aerosol cans formed of a metal sheet formed into the shape of a cylinder and welded along a longitudinal weld zone. In such a case it was particularly difficult, with conventional pistons, to obtain good leakproof contact particularly in the region of the weld zone. Furthermore, the use of an auxiliary mold for producing the piston is dispensed with, which plays a part in appreciably reducing the cost of producing such a packaging assembly. Finally, in the case of an aerosol which has a narrowing near its opening, it is possible to position the piston inside the container even after the narrowed opening has been formed.
In addition to the numerous advantages stated hereinabove, there is also the possibility, for example in the case of airless pump devices, of producing containers which may have any cross section, for example oval, square, triangular or any other polygon-shaped cross section.
In a first embodiment of the present invention, the dispensing member is preferably a valve, the bottom of the container is closed, the second volume contains a propellant, for example a compressed or liquefied gas, capable of pressurizing the product via the piston, and the closed bottom includes a filling element, for example, a valve or its equivalent, capable of allowing the propellant to be introduced into the second volume. The valve may be of any known type. This may, for example, be a valve that has to be depressed or a valve that has to be pivoted. As a preference, the propellant is compressed air or isobutane. The valve or equivalent may be any type of one-way valve, particularly of the ball type.
However, as a preference, the filling element for allowing the propellent gas to be introduced includes a self-sealing plug, particularly one made of an elastomeric material, which can be pierced by a hollow needle communicating with a source of gas, and which can close again in leakproof fashion when the needle is withdrawn from the plug. In this last scenario, on a face which faces towards the bottom, the piston may include a reinforcing element capable of forming a screen, at least opposite the filling element allowing the propellant to be introduced, so as to prevent the needle from being pushed into the piston. This feature is most particularly advantageous when the propellant is introduced into the corresponding volume of the container with the piston arranged at the bottom of the container. Furthermore, a reinforcing element of this kind which is preferably anchored in the piston, may play a part in stiffening the piston structure.
The body of the container may be made of thermoplastic or of metal, particularly tin plate or aluminium.
In the case of an aerosol device, the bottom of the container may be closed by an element which forms a single piece with the body of the container, or by an atta
Baudin Gilles
Lasserre Pierre-Andre
Douglas Steven O.
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
L'Oreal (S.A.)
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