Plastic article or earthenware shaping or treating: apparatus – Female mold and charger to supply fluent stock under... – With product ejector
Reexamination Certificate
2001-07-12
2004-12-07
Heitbrink, Tim (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Female mold and charger to supply fluent stock under...
With product ejector
C264S254000, C264S255000, C264S334000, C425S572000, C425S576000
Reexamination Certificate
active
06827571
ABSTRACT:
FIELD OF THE INVENTION
The present invention is related to the field of plastic material injection-molding.
Still more specifically, the invention is related to a method of injection-molding plastic material articles consisting of a plurality of components, comprising the steps of:
a) providing an injection molding machine having a stack mold in which a center platen on a first side thereof cooperates with a first mold portion via a first separation plane and, on a second side thereof cooperates with a second mold portion via a second separation plane, the stack mold being provided with a plurality of first, smaller cavities as well as with a plurality of second, larger cavities;
b) injection-molding of the first components of the plastic material article in first cavities located in the first separation plane;
c) unmolding the first components from the first cavities;
d) transferring the first components from the first separation plane to the second separation plane;
e) placing the first components into the second cavities;
f) injection-molding the second components on the first components within the second cavities; and
g) unmolding the plastic material articles from the second cavities.
The invention, further, is related to an apparatus for injection-molding plastic material articles consisting of a plurality of components comprising:
a) an injection molding machine having a stack mold in which a center platen on a first side thereof cooperates with a first mold portion via a first separation plane and, on a second side thereof cooperates with a second mold portion via a second separation plane, the stack mold being provided with a plurality of first, smaller cavities as well as with a plurality of second, larger cavities;
b) means for injection-molding
of the first components of the plastic material article in first cavities located in the first separation plane;
of the second components on the first components within the second cavities;
c) a handling system for
unmolding the first components from the first cavities;
transferring the first components from the first separation plane to the second separation plane;
placing the first components into the second cavities, and
unmolding the plastic material articles from the second cavities.
BACKGROUND OF THE INVENTION
A method and an apparatus of the type specified before is disclosed in German patent specification 197 49 245 C2.
The invention, moreover, is related to a method for injection-molding plastic material articles in an injection molding machine having a mold in which at least one first mold portion cooperates with at least one second mold portion via at least one separation plane.
Finally, the invention is related to an apparatus for injection-molding plastic material articles in an injection molding machine comprising a mold in which at least one first mold portion cooperates with at least one second mold portion via at least one separation plane.
A method and an apparatus of the last-mentioned kind are generally known in the art.
Within the technology of plastic material injection-molding, it is well known to manufacture plastic material articles from a plurality of components. These various components may, e.g., consist of different plastic materials in order to take care of different requirements within different surface areas of the manufactured plastic material article. However, the various components may also consist of the same plastic material, however, being of a different color. By doing so, it is possible to manufacture multi-colored plastic material articles.
Various methods and apparatuses have been utilized for manufacturing such multi-component plastic material articles. It is, for example, well known to provide different hollow cavities or two groups of differently shaped hollow cavities, respectively, within one injection mold. In a first step, a first component of plastic material article is manufactured within the small hollow cavities by injection-molding. One may now transfer this component into the larger hollow cavity or, by appropriately displacing the mold one may configurate another hollow cavity above the component just manufactured. In any event, the second component of the plastic material article is directly injection-molded onto the first component in a further method step so that the two components are intimately adhered to one another.
It should be mentioned at this instance that the invention is not at all limited to the field of manufacturing multi-component plastic material articles. Instead, the invention may also be advantageously used for general applications, as long as areas of different temperature within the mold are concerned. The same applies for the use of stack molds which is also to be understood only as an example within the context of the present invention.
Published European patent application EP 0 903 213 A2 discloses various apparatuses and methods for manufacturing such plastic material articles. However, a technology is utilized in which an arm of a handling system or robot transversely enters into a gap between two mold portions of an injection mold when the latter is in its open operational position. After having entered between the mold portions, appropriate gripping elements transfer the components within the mold and unmold finished plastic material articles from the mold, respectively. In one of the shown and described embodiments (FIGS. 14A through 14L), a stack mold is utilized for that purpose. The term “stack mold” is to be understood to mean an injection-molding tool consisting of at least three portions, the center portion of which being identified as “center platen” within the art. The other two mold portions are located on opposite sides of the center platen. A stack mold, therefore, has at least two separation planes, namely on both opposite sides of the center platen in the transitory region to the two adjacent mold portions.
In the prior art apparatus, there is both a smaller and a larger hollow cavity within each separation plane. The two smaller hollow cavities are used for manufacturing the first component of the plastic material article as already mentioned above. The first components, when having been manufactured, are subsequently transferred to the larger hollow cavities and replete same by about one half. The second component is then directly injection-molded onto the first component within the larger hollow cavity.
The already mentioned robot arm is utilized for transferring the components and for unmolding the finished plastic material articles, respectively. The robot arm is adapted to be displaced in a transversal direction in the one or in the other separation plane and, moreover, may be displaced in a direction parallel to the opening or closing direction, respectively, of the mold so that it may be brought into positions where it is flush with the one or with the other separation plane, respectively.
During the transfer of the first component from the smaller hollow cavity to the larger hollow cavity, a change in separation plane is made in this prior art apparatus. Therefore, a first component having been manufactured within the first separation plane is then transferred into the larger hollow cavity in the other separation plane. For executing these transfers, the robot has a holding assembly on its free end. On both sides of the holding assembly, there are two grippers each for gripping components or work pieces, respectively, the grippers being configurated, for example, as suction heads. The grippers on each of the sides have a distance one from the other that is equal to the distance between the smaller and the larger hollow cavity within the two separation planes of the mold. The holding assembly may be pivoted by 180° about an axis lying in the center between the two grippers and extending parallel to the direction of opening and closing of the mold. This prior art apparatus together with its associated method has two substantial disadvantages:
The first disadvantage consists in that each separation plane is provided wit
Heitbrink Tim
Knobbe Martens Olson & Bear LLP
Richard Herbst GmbH
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