JPH0627384Y2 - Preform for blow molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a bottomed preform (bottomed parison) for producing a stretch blow-molded container in which the tubular wall of the cross-section of the tubular body is not a perfect circle. It is a thing.

(Problems to be Solved by Conventional Techniques and Inventions) Conventionally, a blow molding preform in which a tubular wall in a cross section of a tubular body portion is a perfect circle is blow-molded, and a tubular wall of the tubular cross section of the tubular body portion is formed. It is well known to manufacture a blow-molded container having a perfect circle or a shape close to a perfect circle. When a preform having the same shape as this case is used and a container having a cylindrical wall of a cross-section of the cylindrical body portion which is not a perfect circle, for example, an ellipse, a rhombus, a rectangle, etc. is manufactured by blow molding, the obtained container is The wall thickness becomes non-uniform, resulting in a thicker portion than necessary. Such inconvenience is due to the fact that the extent to which the cylindrical wall shape of the cross-section differs from a perfect circle increases, for example, the difference in length between the major axis and the minor axis in an ellipse or rhombus increases, and the longer side in a rectangle. Becomes more significant as the difference in length between the shorter side and the shorter side becomes larger.

(Means for Solving the Problem) The present invention is intended to provide a blow molding preform that does not cause the above-mentioned inconvenience, and as a preform thereof, a cross-section of a tubular body portion is used. The shape of the cylinder wall is similar to or similar to the shape of the cylinder wall of the cross section of the cylinder part of the blow molding container that is the target product, and the preform is blow molded on the bottom of the preform. The above object is achieved by providing a projection having an abutment surface for directing the preform when it is inserted into the mold.

The present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic vertical sectional front view of an example of the preform of the present invention, FIG. 2 is a schematic bottom view of the preform shown in FIG. 1, and FIG. 3 is a schematic vertical sectional front view of another example of the preform of the present invention. Is a schematic bottom view of the preform shown in FIG. 3, FIG. 5 is an explanatory view showing one embodiment of blow molding using the preform of the present invention, and FIG. 6 is a vertical section of yet another example of the preform of the present invention. FIG. 7 is a schematic front view and FIG. 7 is a schematic bottom view of the preform shown in FIG.

In the figure, 1 is a preform of the present invention, 2 is a preform 1
The cylindrical body part blown in 3 is a plug part, 4 is a neck ring formed in the plug part, and 5 is left in a plastic injection port part of a mold when a preform is manufactured by injection molding. Marks of sprue, 6, 7 and 9 are protrusions provided on the bottom of the preform, 8 is the inner surface of the cylinder part of the preform, 10 is an air cylinder, 11 is a rod attached to the air cylinder so that it can move forward and backward, 12 Is a blow molding die.

The attached drawings show three examples of the preform of the present invention shown in FIGS. 1 and 2, 3, 4 and 6 and 7, and FIGS. As shown in FIGS. 4 and 7, the cross section of the tubular portion 2 of the preform has an elliptical shape, and these preforms 1 have a tubular portion cross section having a shape similar to this elliptical shape. It is a preform for manufacturing blow-molded containers. (In FIG. 2, the true circle shown between the ellipse showing the shape of the tubular portion 2 and the true circle showing the outer edge of the neck ring 4 indicates that the lower part of the neck ring in the preform 1 is The cross section of the circle is continuously shown in the plug portion 3 and represents this.) In order to obtain a blow-molded container having an intended shape from the preform having the above-mentioned shape, the preform is blown. It must be placed in the molding die at a position where the major and minor axes of the ellipse of the preform overlap the major and minor axes of the ellipse of the mold cavity.

As described above, in order to place the preform in an appropriate position in the cavity of the blow molding die, 6, in FIG.
The protrusion shown by 7 in FIG. 3 and 9 in FIG. 6 is formed on the preform. These protrusions can be formed at the same time when the preform 1 is manufactured by injection molding.

Next, a fifth embodiment in which the preform 1 shown in FIGS. 1 and 2 is positioned at an appropriate place in the blow molding die
This will be described with reference to the figure.

The preform 1 moves in the direction of arrow B along the circular orbit indicated by A. During the movement, the preform 1 is rotating in the direction of the arrow C, and when it comes near the point indicated by D, the rod 11
When the protruding cylinder 6 of the rotating preform 1 abuts on the rod 11 while the air cylinder having the arrow is moving in parallel, the rotation of the preform 1 in the direction of the arrow C is stopped and then stopped. It is inserted into the mold 12 in the state. The air cylinder so that the preform 1 will be in the proper position when it is inserted into the blow mold 12.
If 10 is installed, the above purpose can be achieved. When the preform 1 comes near the point indicated by E on the track A in FIG. 5, a device for cutting off the protrusion 6 and the sprue mark 5 provided on the preform 1 is provided and these are removed. Is good.

The preform 1 shown in FIGS. 3 and 4 is also blow-molded in the same manner as above.

The protrusion 9 formed on the preform 1 shown in FIGS. 6 and 7 is a semi-conical trapezoid having a flat contact surface, and when the protrusion 9 comes to a predetermined position by using a photoelectric sensor. ,
The contact surface is sensed to generate a signal to stop the rotation of the preform 1 (the rotation of arrow C in FIG. 5).
The preform 1 is placed at an appropriate position in a blow molding die.

As described above, in the gist of the present invention, the projecting body having the contact surface for making the preform directional includes not only mechanical contact but also light contact. .

Further, in the gist of the present invention, the similar shape that the cross section of the tubular part of the preform is similar to or similar to that of the container of the target object means that the cross section of the tubular part of the preform in the present invention is geometric. Is not limited to a geometrically accurate similar shape,
It shows that a similar shape may be used.

As an apparatus for blow molding using the preform of the present invention, an ordinary blow molding machine can be used except that the cavity shape of the mold corresponds to the shape of the preform.

(Effect of the Invention) According to the present invention, the preform can be properly positioned in the blow molding die, and the cylindrical wall of the cross section of the cylindrical portion of the blow molding container has a shape significantly separated from the true circle. Even if there is, a blow-molded container of excellent quality can be easily obtained without causing unevenness in the thick and thin portions of the cylinder wall.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional front view of an example of the preform of the present invention, FIG. 2 is a schematic bottom view of the preform shown in FIG. 1, and FIG. 3 is a schematic vertical sectional front view of another example of the preform of the present invention. Is a schematic bottom view of the preform shown in FIG. 3, FIG. 5 is an explanatory view showing one embodiment of blow molding using the preform of the present invention, and FIG. 6 is a vertical section of yet another example of the preform of the present invention. FIG. 7 is a schematic front view and FIG. 7 is a schematic bottom view of the preform shown in FIG. In the figure, 1 is a preform, 2 is a cylinder part blown in the preform 1, 3 is a plug part of the preform, 6,
7 and 9 are protrusions provided on the bottom of the preform 1,
12 is a blow molding die.

Claims (1)

[Scope of utility model registration request] 1. A bottomed preform for producing a stretch blow-molded container in which the tubular wall of the tubular section has a non-circular tubular wall, and the tubular section of the preform has the lateral section of the object container. A similar or similar shape to that of the above, and at the bottom of this preform, when the preform is inserted into the blow molding die, a protrusion having a contact surface for giving directionality to the preform is provided. A preform for blow molding that is characterized by