Dispensing – Collapsible wall-type container
Reexamination Certificate
2002-04-26
2004-08-31
Bomberg, Kenneth (Department: 3754)
Dispensing
Collapsible wall-type container
C222S558000, C215S235000, C220S833000, C220S837000
Reexamination Certificate
active
06783029
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns flexible tubes intended for storing and dispensing liquid products of varying viscosity, in the form of gels, creams or pastes, typically toothpaste or cosmetic products. These tubes have a head which has neither neck nor shoulder, the skirt being directly adjacent to a rigid capping. Said rigid capping is formed either of an end part fitted with a cap, or with a hinge cap comprising a base and an end cap which pivots around a hinge attached at the base used to close a dispensing aperture arranged on said base.
DESCRIPTION OF RELATED ART
Numerous documents disclose said tubes whose head, which has neither a neck nor a shoulder, is both reduced in size and has an original, attractive appearance.
Often the end of the tube is directly fitted with a service cap. Document U.S. Pat. No. 4,470,521 for example describes a tube having an elongated, elliptical or polygonal section fitted with a service cap substantially in the extension of the skirt, the hinge being positioned on the circumference in the zone of the long axis, and the dispensing aperture being positioned as far as possible from said hinge. In addition to its debatable ease of use on account of the scarcely practical hinge position, this tube is moulded in a single material which does not make it possible to obtain a tube which satisfactorily meets constraints of use: the skirt must be very flexible to allow good restitution of the product contained in the tube, but the hinge must be able to withstand mechanical demands (mainly bending, but also twisting and extension) placed on the hinge throughout the time of use of the dispenser tube. Yet good fatigue resistance is not obtained with the most flexible plastic materials (typically low density polyethylene) but with stiffer materials (typically polypropylene) which, in addition, do not have fusion compatibility with the more flexible materials of the skirt, such as low density polyethylene. Moreover, for service caps, problem-free repeated closing of the cap requires a capsule in rigid material. The cap must pivot around its axis so that the various components intended to cooperate with one another to close the dispensing aperture and temporarily fix the cap to its base may do so in repeated manner and always by positioning themselves exactly opposite one another. To produce such tubes by injection moulding of a single material, persons skilled in the art are therefore compelled to find a delicate compromise between two opposing requirements which does not make it possible to obtain satisfactory tubes.
French model 98 7300 published under numbers 535 807 to 535 814 (L'Oréal) provides a tube with neither neck nor shoulder which is both reduced in size and of pleasing, original appearance. The tube is elliptical, the service cap is positioned in the extension of the skirt but, unlike the tube in U.S. Pat. No. 4,470,521, the hinge is positioned in the zone of the short axis which makes the tube easier to hold during the various cap handling operations. However, this tube raises the same problem as the previous tube: if it is produced by injection moulding in a single material, this material can only be a compromise between two opposing requirements.
Since injection moulding with a single material does not lead to a satisfactory solution, the applicant sought to bring about co-existence between the flexible skirt material and the rigid material of a capping such as described by French model 987300. It is not sufficient to solve the problem of fusion compatibility, there is also the problem of the tube's percentage of product restitution; when the tube is nearly finished, the user has to try and expel the product remaining in the vicinity of the rigid cap and is no longer able to press the skirt with the same efficacy as when the middle of the skirt is pressed.
The applicant has therefore set out to produce a tube, under satisfactory economic conditions, which comprises a more compact head than conventional heads with a neck and shoulder, said tube making it nevertheless possible to obtain a product restitution percentage of over 85% with rigid capping directly adjacent to a flexible skirt.
SUMMARY OF THE INVENTION
The first subject of the invention is a tube fitted with a head intended to fix capping, the second subject of the invention described below, and with a cylindrical or prismatic skirt having an orthogonal section of any shape (elliptical, round, polygonal, etc..) whose largest inscribed circle has a diameter D, characterized in that the head is provided with a round cylindrical wall extending towards inside the tube and surrounding an opening that is concentric to said inscribed circle, said opening—which will be hereinafter called “large-diameter-opening” for simplification—having a diameter typically lying between 0.5*D and 0.9*D, and in that it essentially occupies the inner volume of the skirt end over a distance that is less than D, preferably less than D/3.
Therefore the capping is not fixed directly to the skirt but on a head of special shape, largely flattened, so as to take up as little space as possible. The capping is fitted with a circular skirt whose diameter is equal to or slightly greater than the diameter of the large-diameter-opening of the head. To fix this capping to the tube, said cylindrical skirt is force fitted into the round cylindrical wall surrounding the large-diameter-opening as far as its end position. The open end of the capping skirt is provided with substantially irreversible interlocking means such as a click-fit rim which relaxes outwardly under elastic effect as soon as it passes through the lower end of the cylindrical wall surrounding the opening.
In this manner, a rigid, sealed contact is made at the large-diameter-opening. The head, made in a fusion compatible material with the material of the skirt, is sufficiently flexible so that its peripheral part, which corresponds to the junction between head and skirt, is able to undergo substantial deformation, whereas the adjacent parts corresponding to the rigid capping remain non-deformed. With such deformability it is possible to obtain a high product restitution percentage despite the presence of the rigid capping in the vicinity of the tube end.
The zone next to the cylindrical wall which surrounds the large-diameter-opening must be little deformable however, since the cylindrical wall in cooperation with the cylindrical capping skirt must ensure two functions: sealing and substantially irreversible interlocking. Said cylindrical wall must be sufficiently distant from the deformable peripheral part of the tube so that the major deformations applied to this peripheral part lose their magnitude when transmitted to the cylindrical wall which surrounds the large-diameter-opening. On this account, the diameter of the so-called large-diameter-opening is limited to 90% of the diameter of the largest inscribed circle.
Also, the cylindrical wall surrounding the large-diameter-opening participates in the rigidity of the head. It is in this sense that the opening must have a large diameter, typically greater than 0.5 times the diameter of the largest inscribed circle, bearing in mind that it may be smaller if other means are used to rigidify said head, such as the means described below in a particular embodiment in which the head is provided with bosses.
The head occupies the inside of the volume delimited by the skirt end over a short distance. It therefore takes up little volume. In this manner, the quantity of material to be moulded is reduced which may lead to advantageous economic consequences regarding material costs and even production rates when the head is moulded and simultaneously welded to the skirt. Typically, the height of the round cylindrical wall surrounding the large-diameter-opening is less than D and preferably less than D/5.
Preferably, the head is also provided with a peripheral wall which extends the skirt of the flexible tube by a small distance, typically in the order of one millimetre, being slightly stagger
Bomberg Kenneth
Buechner Patrick
Cebal S.A.
Dennison Schultz Dougherty & MacDonald
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