This invention relates to an applicator for creams and viscous liquids and more particularly to an applicator for cosmetic creams.
Many products, and particularly cosmetic products, take the form of creams or viscous liquids. Among such materials there may be mentioned skin creams, sun-shield lotions and especially deodorants and antiperspirants. Various types of applicators or dispensers have been proposed for such substances. Among these have been dispensers in which the cream is forced out of a tube having a perforated head by the pressure of a piston advanced inside the tube. The piston causes the fluid material to be forced through the perforations in the dispenser head and the material is applied by rubbing the head on the surface to be coated, the head thus serving as an applicator member.
One difficulty which has arisen with such dispensers is that after use fluid material remains lodged in the perforations of the head, or just below the head. If the dispenser is then subjected to an increase in temperature or possibly a decrease in atmospheric pressure, even to a relatively modest extent, the fluid will flow out of the perforated head. Often material as extruded will dry and cake, making it difficult to use the dispenser and presenting an unsightly appearance.
The present invention overcomes these disadvantages and provides a dispenser or applicator for viscous fluids or creams in which the contents may be advanced from a container through a perforated applicator member whence they can be applied to the surface as desired. When the application has been completed the device may be withdrawn from the surface and stored indefinitely through substantial changes in ambient temperature and pressure without undesired extrusion of the stored material.
GB-A-1358608 discloses cosmetic applications in which a piston-expelled fluent cosmetic preparation is forced through the pores of an applicator member in the form of a foam pad to impregnate the foam pad with the preparation. The pore size is said to be small enough to prevent dripping when impregnated but large enough to permit the preparation to be pressed through the pad during use.
In all the embodiments disclosed in GB-A-1358608, the foam pad expands outwardly under the influence of pressurised perpa- ration and in one embodiment the initial position of the pad leaves a reservoir before the cosmetic material is urged into it. However, since the pad of this known applicator is made of foam the pores of which, when occluded, would prevent the pad from springing back, the teaching of this document does not give any hint to solve the problem stored in this application.
What constitutes an applicator according to this invention is set forth in the following claim 1, the classifying portion of which is drawn from the disclosure of GB-A-1358608.
An applicator in accordance with this invention is characterised in that. the applicator member is a cap the central portion of which is provided with at least one orifice therein and is capable of springing back to its original shape upon release of the pressure to free said at least one orifice of cream or viscous fluid.
The invention will now be described with reference to the drawings, in which:
Referring to the drawings, an applicator according to the invention comprises a container 10 which is normally, but not necessarily, a cylindrical tube. The lower end of the container is closed by a plug 12 having a lug 13 which engages an inwardly turned flange 11 at the bottom of the container. The plug 12 may be provided with a collar 14, which may be knurled, if desired, and by means of which the plug 12 may be rotated within the container 10.
The outer surface of the plug 12 is threaded as at 15 and a hollow piston 16 is interposed between the plug 12 and the container 10. Its inner wall is threaded as at 17, these threads engaging the threads 15 of the plug 12.
At the right hand side of Fig. 1 the piston 16 is shown fully retracted and seated at the bottom of container 10, leaving a space 33 of variable volume above it, which space may be filled with the liquid or cream to be dispensed.
The inner wall of container 10 is provided with vertical guide means in the form of ribs 18 which engage vertical slots 19 in the wall of piston 16 and prevent the piston from rotating. Thus when plug 12 is rotated by means of collar 14 the piston 16 is moved upwardly, from the position shown on the right side of Fig. 1, ultimately reaching the position shown at the left hand side of Fig. 1.
At the top of the piston 16 is provided an annular collar 20 which fits closely against the inner surface of the container and slides on that surface as the piston moves upwardly, thus providing a seal for the liquid material in space 33.
The top of container 10 is split to provide an outer rim 21 which branches from a central wall 22 of the container. The outer rim 21 has an annular channel 23.
The upper end of container 10 is closed by an applicator member in the form of a cap 24 which is held in place by the engagement of an inner ring 25 in the annular channel 23 of the container rim 21. A vertical ring 26 extending down from the under surface of cap 24 engages the outer surface of the central wall 22 of the container.
As shown more particularly in Fig. 2, the cap 24 has an outer section 27, which is relatively thick and an inner section 28 which is thin. At the center of the inner section there is provided an orifice 29. The cap 24 is made of a material which is strong and resilient so that if the inner section 28 is pressed it will bend inwardly toward the container 10, but when released will spring back to its original shape. For many purposes it will be desirable to have the cap 24 soft to the touch. Polypropylene and polyethylene will provide these properties.
Over the cap 24 there may be placed a cover 30. Cover 30 has an inner ring 31 which bears on cap 24. Cover 30 is sized to make a friction fit with the side of the cap 24 and the container 10, as at 32.
In operation, the cover 30 is removed and the collar 14 is rotated to move the piston 16 upwardly, forcing the cream or liquid material in the space 33 into the upper domelike part of cap 24, out the orifice 29 and onto the outer surface of the cap. The user then applies the liquid material to the surface to be coated. In doing so be presses the domed surface of the cap 24 against the surface to be coated, causing at least the inner section 28 of the cap 24 to be deformed inwardly as shown in Fig. 3. In this process, additional liquid material is squeezed from the top of the container through orifice 29.
When the application has been completed, the applicator is removed from the coated surface, relieving the pressure on the cap 24. The thin, resilient inner section 28 then springs back to its original shape, leaving an air space 34 at the top of the cap and freeing the orifice of liquid material. The presence of this air space 34 acts as a reservoir to receive liquid material caused to expand from the space 33 by changes in temperature or pressure and avoiding undesired extrusion of such material through orifice 29.
The materials used to make the applicator can be varied widely. For various reasons including texture, economy and chemical inertness polypropylene is preferred, though for some parts, for example, the cover 30, low density polyethylene is the substance of choice. Obviously more expensive materials such as nylon, polymethylmethacrylate, or other plastics, or various rubbers, may be employed, as may metals such as stainless steel.
Many variations are possible in the structure of the applicator. For example, a central threaded rod may be used to advance a piston to extrude the stored material in a fashion analogous to that shown in United States Patents Nos. 2,935,191 and 2,818,167. Alternatively, the container may be a simple squeeze bottle. Finally, although only a single orifice has been described it is obvious that multiple orifices may be used as may slots or openings of other shapes.