Plastic article or earthenware shaping or treating: apparatus – Female mold and means to shape parison directly by internal... – With heating or cooling means
Reexamination Certificate
2000-06-30
2002-10-01
Davis, Robert (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Female mold and means to shape parison directly by internal...
With heating or cooling means
C425S452000, C425S529000, C425S534000
Reexamination Certificate
active
06457967
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a biaxially blow molding apparatus forming a predetermined shape of molded product by transporting a preform carrier carrying a preform along a transporting path extending across a heating portion and a stretch-molding portion and by performing biaxially stretching blow molding for the preform.
2. Description of the Related Art
A biaxially stretching blow molding apparatus producing resin products, such as PET bottle or so forth, by biaxially stretching blow molding, is constructed to heat a primary molded product which is called as a preform, up to a temperature adapted for molding during transportation across the heating portion, and then perform biaxially stretching blow molding for the preform in a stretch-molding die forming the stretch-molding portion.
A typical biaxially stretching blow molding apparatus has a construction including a preform supply portion, a preform heating portion, a stretch-molding portion and a molded product taking out portion, and continuously or intermittently circulating a plurality of preforms along a guide rail defining a transporting path extending across respective of the foregoing portions. On the other hand, a typical preform carrier has a construction including a slide portion guided by the guide rail to move therealong, and a core portion extending from the slide portion to be inserted into the preform.
The preform is loaded on each preform carrier in the preform supply portion so that an opening mouth of the preform is set on the core portion of the preform carrier. On the other hand, the molded product obtained by performing biaxially stretching blow molding for the preform in the stretch-molding portion is unloaded from each preform carrier by releasing an opening in a neck portion of the molded product from the core portion of the preform carrier in the product taking out portion and collected in a predetermined collecting site. Furthermore, the empty preform carrier unloaded the molded product is returned to the preform supply portion for loading the next preform.
In the biaxially stretching blow molding apparatus having a construction to support the preform by the preform carrier which is continuously transported along the predetermined circulating path, it has been strongly demanded to speeding up operation at respective portions for improving overall process performance and whereby for improving cost effectiveness.
On the other hand, the preform carrier unloaded the molded product after passing through the stretch-molding portion is schematically returned to the preform supply portion again by-passing the stretch molding portion. When the by-pass passage for the empty preform carrier can be formed through a dead space below the stretch-molding portion, the circulating path may be constructed in compact. In such case, height difference is caused in the circulating path to require transfer of the preform, the molded product and the preform carrier between the transporting paths having height difference. If transfer operation can be done efficiently, process speed of the biaxially stretching blow molding apparatus can be improved.
Next, the preform transported by the preform carrier along the circulating path is formed into the molded product which has greater width and greater height in comparison with the preform in the stretch-molding portion. Therefore, it becomes necessary to provide greater feeding pitch of the preform carrier on the upstream side of the stretch-molding portion. If transporting operation for the preform carrier can be done efficiently by converting operation of the feeding pitch and with widened feeding pitch, process speed of the biaxially stretching blow molding apparatus can be further improved.
On the other hand, a mold clamping mechanism which opens and closes a pair of stretch-molding dies in order to perform stretch-molding of the preform, generally has a construction to open and close each stretch-molding dies which are slidably supported, by means of an air cylinder via a toggle link mechanism. If opening and closing operation of the stretch-molding dies by the mold clamping mechanism can be done efficiently, process speed of the biaxially stretching blow molding apparatus can be further improved.
SUMMARY OF THE INVENTION
The present invention has been worked out in order to satisfy demands set forth above. Therefore, it is an object of the present invention to provide a biaxially stretching blow molding apparatus which has high process speed by improving efficiency of operation in respective components.
Another and more particular object of the present invention to provide a biaxially stretching blow molding apparatus which can efficiently perform transfer operation of a preform, a molded product and a preform carrier between transporting paths having height difference.
A further object of the present invention is to provide a biaxially stretching blow molding apparatus which can efficiently perform an operation for expanding a feeding pitch of the preform carriers on upstream side of a stretch-molding portion and a transporting operation of the preform carrier with the expanded feeding pitch.
A still further object of the present invention is to provide a biaxially stretching blow molding apparatus which can efficiently perform mold clamping operation of a pair of stretch-molding dies for performing biaxially stretching blow molding.
In order to accomplish the above-identified and other objects, according to the first aspect of the present invention, a biaxially stretching blow molding apparatus perform biaxial stretch-molding for a preform into a predetermined shape by transporting a preform carrier supporting the preform along a transporting path extending across a heating portion and a stretch-molding portion, comprises:
first and second reversing means for reversing the preform carrier;
first and second transporting paths forming the transporting path;
the first reversing means receiving the preform carrier transported in up-side-down position along the second transporting path, reversing the received preform carrier into elected position, and transferring the preform carrier thus reversed to the first transporting path; and
the second reversing means receiving the preform carrier transported in elected position along the first transporting path, reversing the received preform carrier into the up-side-down position, and transferring the preform carrier thus reversed to the second transporting path.
In order to make the first and second transporting paths compact, it is preferred that the first transporting path is an upper transporting path extending across a stretch-molding position of the stretch-molding portion, and the second transporting path is a lower transporting path extending lower side of the stretch-molding portion. With this construction, in comparison with the case where the second transporting path is arranged by-passing the stretch molding portion having largest dimension in the width direction in lateral direction, the biaxially stretching blow molding apparatus can have compact construction.
On the other hand, it is possible that at least one of the first and second reversing means has a pivoting member pivoting about a predetermined pivot center and a pair of preform holding portion formed at symmetric positions of the pivoting member with respect to the pivot center. In this case, it is desirable that one of the preform holding portions being placed at a height corresponding to the upper transporting path and the other preform holding portion being placed at a height corresponding to the lower transporting path at pivot stop position of the pivoting member.
With the construction set forth above, whenever the pivoting member is pivoted, both of the preform carrier holding portions are respectively positioned at the height positions corresponding to the upper and lower transporting paths. Therefore, transfer of the preform carriers between respective preform carrier holding portions and the
Fukai Hidehiko
Seki Masanobu
Suzuki Saburo
Burns Doane Swecker & Mathis L.L.P.
Davis Robert
Frontier Inc.
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