Plastic article or earthenware shaping or treating: apparatus – Female mold and means to shape parison directly by internal... – Including means to prepare parison
Reexamination Certificate
1998-12-01
2001-03-06
Davis, Robert (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Female mold and means to shape parison directly by internal...
Including means to prepare parison
C425S537000, C425S538000, C425S541000
Reexamination Certificate
active
06196829
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for forming a hollow article using an extrusion molding technology and an apparatus for the same, more particularly to a method for forming a hollow article using a plurality of blow molding units and an apparatus for the same.
2. Description of the Related Art
When comparatively large hollow articles such as a fuel tank for use in cars and a can are manufactured using an extrusion blow molding technology, a plurality of blow molding units, each of which comprises a blow molding mold, have been used and the receiving position where a parison is received and the position where the parison is expanded by blowing air thereinto have been made to be separate from each other. As such conventional kinds of apparatuses for the forming hollow article, the apparatus disclosed in Japanese Patent Application Laid-open No. 251441/1995, for example, has been known. The features of this apparatus are as follows.
(1) There are two or more blow molding units and there are one or more extrusion heads of an extrusion system.
(2) Each of the blow molding units is moved from a position apart in a certain direction to a detaching position of the hollow article by a first movement operation, and moved to a receiving position for receiving the parison by a second movement operation. Movement directions in the first and second movement operations are different.
(3) Each of the blow molding units is made to be an open state after it reaches the detaching position. Thereafter, the hollow article already molded in a blow molding mold is taken out, and then the blow molding mold unit is moved to the receiving position with the blow molding mold left in an open state.
However, the apparatus for forming a hollow article using the conventional extrusion molding technology has the following technological problems.
Specifically, each of the blow molding units is moved from the position apart in a certain direction to the detaching position by the first movement operation, and moved to the receiving position by a second movement operation which moves the blow molding unit to a different movement direction from the movement direction of the first movement operation. For this reason, driving devices to move the blow molding unit into the two directions are needed, so that the structure of the apparatus will be complicated and disadvantageous economically.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a method for forming a hollow article and an apparatus for the same, which are capable of not only simplifying a driving device for driving a blow molding unit and a structure of the blow molding unit but also significantly reducing a space for accommodating the blow molding unit.
Another object of the present invention is to provide a method for forming a hollow article and an apparatus for same, which are capable of performing a high cycle molding and enhancing effects of the high cycle molding by combining it with a continuous extrusion of a parison from an extrusion head.
Still another object of the present invention is to provide a method for forming a hollow article and an apparatus for same, which are capable of ensuring the maintenance to be compatible with the ensuring of an operation rate.
Still another object of the present invention is to provide a method for forming a hollow article and an apparatus for same, which are capable of not only enhancing operability and safety but also achieving a low cost by simplifying the structure.
To achieve the above-described objects, the present invention provides a method for forming a hollow article comprising the steps of:
allowing a blow molding mold of one of two blow molding units to receive a parison in a receiving position and to take a mold close state, each blow molding unit including a carriage which has an end portion supported by a swinging fulcrum so as to freely swing and a blow molding mold which is disposed on the carriage; swinging one of the blow molding units around the swinging fulcrum, allowing the blow molding mold thereof to pass through a detaching position from a receiving position so as to reach to a shunting position for avoiding an interference of one blow molding unit with the other blow molding unit; returning the blow molding mold from the shunting position to the detaching position and causing the blow molding mold to take a mold open state, thereby taking out a hollow article which is formed by blow molding in the blow molding mold; moving the blow molding mold kept in the mold open state to the receiving position; and swinging the other blow molding unit so as to move the other blow molding mold thereof from another shunting position to another detaching position and the receiving position, and returning the other blow molding unit to the another shunting position from the receiving position via the another detaching position similarly to the case of one blow molding unit, immediately after one blow molding unit reached to the shunting position.
In addition, the present invention provides an apparatus for forming a hollow article comprising:
an extrusion device disposed at a fixed location, which includes at least one extrusion head and extrudes downward a parison from the extrusion head, the parison being formed of a thermoplastic material softened by heating; two blow molding units having a carriage, one end portion of which is supported by a swinging fulcrum so as to swing, a blow molding mold disposed on the carriage, and an open-close device allowing the blow molding mold to perform an open-close operation, wherein each blow molding mold is divided into at least two, and has mold components for defining a cavity showing an outline which conforms to the external shape of the hollow article in a state where the mold components are made to be in a mold close state by being driven by the open-close device; and a swing-driving device for driving each blow molding unit so as to swing around corresponding swinging fulcrums, allowing each blow molding mold to occupy a receiving position, a shunting position for avoiding interference of one blow molding unit with the other blow molding unit, and a detaching position, the detaching position and the shunting position being located on one side of a central line of the extrusion device, whereby each blow molding mold receives the parison in the common receiving position, is driven by the open-close device so as to be a mold close state, and moves from the receiving position to the shunting position via the detaching position, and thereafter, each blow molding mold is returned to the detaching position, and driven by the open-close device so as to be a mold open state, and a hollow article which is formed by blow molding the parison in the blow molding mold is taken out, and moved to the receiving position as kept in the mold open state.
In accordance with a further aspect of the invention, the swinging fulcrum of each blow molding unit is set so that each blow molding mold of the two blow molding units occupies the common receiving position and the common detaching position.
The above and other objects, features and advantages of the present invention will become apparent from the following description based on the accompanying drawings which illustrates examples of preferred embodiments of the present invention.
REFERENCES:
patent: 3743466 (1973-07-01), Gampe
patent: 5576034 (1996-11-01), Kiefer et al.
patent: 185110 A1 (1986-06-01), None
Abe Shouji
Kagitani Toshio
Davis Robert
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
The Japan Steel Works Ltd.
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