Glass manufacturing – Processes – Sequentially forming – reheating – and working
Reexamination Certificate
1999-02-09
2001-05-22
Vincent, Sean (Department: 1731)
Glass manufacturing
Processes
Sequentially forming, reheating, and working
C065S076000, C065S079000, C065S080000, C065S081000, C065S105000, C065S112000
Reexamination Certificate
active
06233973
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a new process for molding a glass container. Such containers are particularly adapted for the storing of cosmetic products, notably perfumes.
2. Description of the Related Art
Containers of glass are generally formed by inflation or compression of a preform in a shaping mold, then inflation of the preform in a finishing mold having the dimensions and the form of the container to be made. In the field of cosmetics, in particular perfumes, there is constant research into new aesthetic shapes, always more attractive for the consumer, and/or which are representative of this or that new characteristic of the perfume, notably a particular scent. Recent years have been marked by the appearance of a multitude of new shapes, colors or concepts for the storing of perfumes. Certain of these new concepts have shown themselves to be unsatisfactory or more costly to put into practice.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a new, economically viable process for forming a container of glass.
It is another object of the invention to provide a new, economically viable process for forming a container of glass whose walls include a multitude of air inclusions trapped in the wall material and disposed in a predetermined manner.
It is yet another object of the invention to produce a container presenting an original visual aspect, perfectly reproducible and able to be formed by a totally automatable process.
According to a first aspect of the invention these and other objects are achieved by a process for the forming of a glass container by carrying out the molding in two successive steps: a first step is performed in a preforming mold having pins projecting into the interior of the mold over a length less than the thickness of the walls of the preform of the article, the external walls of the preform presenting, after removal from the mold, recessed portions corresponding to the presence of the projecting pins. The second step is performed in a smooth-walled finishing mold having the shape and the dimensions of the container to be formed, the blowing pressure within the finishing mold being controlled so as to permit a smoothness of the external wall of the container and the formation of air inclusions in the wall of the container. In the preforming mold the material may be brought into intimate contact against the mold walls either by blowing or by pressing with a punch.
There is thus obtained a container presenting particularly original aesthetic characteristics, able to be formed in a perfectly reproducible manner by a process capable of being entirely automated.
Advantageously the pins of the preforming mold are able to pass from a first position in which they do not substantially project relative to the internal walls of the mold to a second position in which they project relative to the internal walls of the mold over a length less than the thickness of the walls of the preform, so as not to penetrate them. The fact that the pins may be retractable facilitates the manner of removing the preform from the mold. In particular, in the case of a totally automated process the possibility of damage or scoring of the glass is avoided.
By way of example the pins may be actuated by a pneumatic system. Preferably all of the pins are actuated in a simultaneous manner by the same pneumatic system. Such pins controlled by a pneumatic system are well known in the field of molding of thermoplastic materials, notably when there is a need to form an orifice opening into a molded piece.
The pins may be of circular, triangular, square, oval or star-shaped cross-section. Other forms may be envisaged as a function of the aesthetic or functional effect of the air inclusions on the consumer, or of the product characteristics to be emphasized by the air inclusions.
Advantageously the preforming and finishing molds are each formed of at least two shell parts able to be closed along at least two lines parallel to the longitudinal axis of the container. In the case of a preforming mold with non-retractable pins, the pins are arranged relative to the line of opening of the mold such that the pins do not interfere with removal from the mold. Furthermore, in this case the parison is lowered into the mold before closing of the mold, so as to avoid scoring of the glass. The glass may be clear or colored glass.
In a variant of the process according to the invention, before being introduced into the finishing mold the preform is reheated so as to facilitate the molding in the finishing mold, the objective being to bring the preform back to a temperature such that the material may be blown and correctly molded in the finishing mold.
In another variant, before being introduced into the finishing mold, the preform is immersed in a bath of molten glass so as to coat the external surface of the preform with a fine glass layer, said fine glass layer not modifying in any substantial way the profile of the external wall of the preform.
In yet a further variant, the container removed from the finishing mold is plunged into a bath of molten glass and again blown in an auxiliary mold, the blowing pressure being controlled so as not to provoke the bursting of the air inclusions. One may thus improve the surface quality of the finished container.
According to a second aspect of the invention there is also provided a glass container obtained by the above process.
Advantageously the air inclusions have dimensions which are variable as a function of the ratio of the dimensions of the preforming mold to those of the finishing mold. In fact, when using a finishing mold of relatively great height for blowing a preform obtained in a mold of smaller height, the material is subjected to stretching which is not identical in all parts of the mold. Thus, due to the greater thickness of the preform in the region of its bottom, the material situated opposed to the blowing nozzle will be stretched less than that situated adjacent to the blowing nozzle. Bubbles will thus decrease in height in the direction towards the bottom of the container.
For example, the container according to the invention may be of the type comprising a body which is surmounted by a neck and closed by a bottom, the air inclusions being of a height continually increasing in the direction towards the neck. With this embodiment, the blowing of the container occurs from its open shoulder so as to cause a stretching of the material and of the air inclusions, to a greater extent in proportion to the closeness to the neck.
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patent: 363190 (1887-05-01), Webb
patent: 1715130 (1929-05-01), Haley
patent: 1816045 (1931-07-01), Haley
patent: 4367086 (1983-01-01), Sarpaneva
patent: 1596463 (1971-02-01), None
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patent: 1058684 (1954-03-01), None
patent: 2134338 (1972-12-01), None
patent: 2134337 (1972-12-01), None
L'Oreal
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Vincent Sean
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