JPH044124B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a parison wall thickness adjusting device in a blow molding machine.

[Prior Art] In order to make the wall thickness of a blow-molded product uniform, an axial wall thickness control device for a parison has conventionally been used. In order to make the wall thickness of the molded product ideal, it is desirable to control the wall thickness in the circumferential direction of the parison as well.
A wall thickness adjusting device as shown in Publication No. 140032 was devised.

Figure 4 shows a parison head of a blow molding machine equipped with such a wall thickness adjustment device, where 1 is the head body, 2 is the die provided at the lower end of the head body, and 3
is a core disposed at the center of the die 2 to form a slit 5 through which the parison 4 is injected between the dies 2;
6 is a rod for raising and lowering the core 3 to adjust the thickness of the slit 5, 7 is a piston for injecting the parison 4, and 8 is an injection cylinder, as shown in FIGS. 5 and 6. An arcuate groove 9 is partially provided in the circumferential direction on the surface of the slit 5 at the lower end of the die 2, and adjustment segments 10 and 11 for adjusting the interval between the slits 5 are disposed within the groove 9. .

The segments 10 and 11 have substantially symmetrical arc shapes as shown in FIG. 7, and have outer ends 10a and 1, respectively.
1a is formed into a curved shape and is slidably fitted into both ends of the groove 9, and bracket portions 10b and 11b are protruded from the inner end of each of the stepped pins 12 to accommodate the small diameter of the stepped pin 12. The injection pressure of the parison 4 from the slit 5 side causes the pin 1 to
It is constructed so that it can bulge outward with 2 as the center. Furthermore, a rod 14 of a push device 13 for pressing the segments 10 and 11 toward the slit 5 is slidably connected to the outer surface of the large diameter portion of the pin 12 through a pin 15 through the die 2. .

Therefore, when the rod 14 is contracted, the rod 14
and pin 12 are slidably connected by pin 15, only rod 14 moves to the right in FIG. 5, and when parison 4 is ejected from slit 5 in this state, the pressure As a result, the segments 10 and 11 move in a bulging manner to the position indicated by the imaginary line, and stop when the pin 12 comes into contact with the rod 14. As a result, the distance between the slits 5 is increased in the segments 10 and 11, and the thickness of the parison 4 to be injected can therefore be increased.

[Problems to be Solved by the Invention] However, in such a conventional wall thickness adjusting device, the wall thickness of the parison 4 can only be adjusted partially, and the thickness of the parison 4 can only be adjusted partially. It was not possible to make the wall thickness ideal. In addition, in the case of the conventional device, when the segments 10 and 11 move so as to bulge outward, their outer ends 10a and 11
If a slight gap is formed between a and both ends of the concave groove 9 in the die 2, and the parison 4 is extruded in this state, an axial protrusion will be formed on the outer wall of the parison 4, so the segment On the lower end surface of the die 2 where the outer ends 10a, 11a of the segments 10, 11 are located, there is a gap between the outer ends 10a, 11a formed when the segments 10, 11 expand and both ends of the groove 9.
It was necessary to provide closing plates 16, 16 to superficially close the gap.

In view of these circumstances, the present invention allows the thickness of the parison to be adjusted in its entirety from the circumferential direction, and also eliminates the need for the closing plate.

[Means for Solving the Problems] The present invention provides an annular groove in the slit surface at the lower end of the die, is divided into four or more parts, and is provided with a curved protrusion and a curved seat on the upper and lower sides of one end. A wall thickness adjustment ring in which arc-shaped segments each having a curved seat and a curved protrusion that can be fitted to the curved protrusion and the curved seat on the upper and lower sides are connected with pins is disposed in the groove;
Each pin connecting portion of the wall thickness adjustment ring has a configuration in which a rod of a push/pull device is connected to each pin connecting portion of the wall thickness adjusting ring by penetrating the die from the outside of the die.

[Function] Therefore, by pushing and pulling the rod of the push-pull device at each part, the adjustment ring formed by connecting the segments with pins is deformed, and by adjusting the shape of this ring, the wall thickness of the parison can be adjusted from the circumferential direction as a whole. adjusted accordingly.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

In the present invention, as shown in FIGS. 1 and 2, an annular groove 17 is provided on the surface of the slit 5 at the lower end of the die 2, and an adjustment ring 18 is provided within the groove 17 for adjusting the interval between the slits 5. has been set up.

The adjustment ring 18 is composed of arc-shaped segments 19 with a four-part structure, and each segment 19 has curved protrusions 19a and curved seats 19b arranged vertically alternately at both ends of each segment 19. The curved protrusions 19a of the segments 19, 19 and the curved seats 19b are engaged and rotatably connected by pins 20. Further, each pin 20 has a cylinder 21a as a push/pull device arranged radially outside the die 2.
-21d rods 22a-22d pass through the die 2 and are connected, respectively.

In FIG. 1, the same reference numerals as in FIG. 4 indicate the same parts.

In such a configuration, when the adjustment ring 1 is pushed into the rods 22a, 22c of one of the opposing cylinders 21a, 21c and pulled back the rods 22b, 22d of the other opposing cylinder 21b, 21d.
8 is deformed into an ellipse as a whole with the core 3 as the center. In this case, the distance between the slits 5 becomes smaller in the portion where the rods 22a, 22c are pushed in, and the distance between the slits 5 becomes larger in the portion where the rods 22b, 22d are pulled back. Alternatively, for example, the rod 22a of the cylinder 21a may be fixed, and the rod 22a of the cylinder 21c may be fixed.
2c, push (or pull back) the cylinder 21b,
When the rods 22b and 22d of 21d are pulled back (or pushed in), the ellipse formed by the adjustment ring 18 is eccentric from the center of the core 3. In this case, only the spacing between the slits 5 in the portion where the rod 22a is pushed can be made smaller (or larger).

Therefore, by pushing and pulling back the rods 22a to 22d as necessary, the thickness of the parison 4 can be adjusted as a whole from the circumferential direction. By doing so, a parison 4 having an ideal thickness corresponding to the shape of the molded product to be molded can be obtained.

Further, in the present invention, the slit 5 is formed by the core 3 and the inner peripheral surface of the adjustment ring 18,
and each segment 19 constituting the adjustment ring 18
Since the adjustment ring 18 is connected by the pin 20, the inner peripheral surface of the adjustment ring 18 remains continuous no matter how the adjustment ring 18 deforms. There is no gap between the outer ends 10a, 11a of the grooves 10, 11 and both ends of the groove 9, so there is no need for a closing plate 16 to close the gap.

In addition, the end shape of the segment 19 and the pin 20
Since the shape is simpler than that of the conventional example shown in FIG. 7, the segments 19 and pins 20 can be easily manufactured, and the thickness adjustment ring 18 can be easily adjusted.

In the embodiment described above, the adjustment ring 18 is constituted by the segments 19 having a four-division structure, but it is also possible to have a configuration in which the adjustment ring 18 is divided into four or more parts, and it is of course possible to make various changes without departing from the gist of the present invention. It is.

[Effects of the Invention] As explained above, according to the present invention, the following excellent effects can be achieved.

(1) The adjustment ring, which has a connecting structure of four or more segments, can be deformed to adjust the slit spacing between the core and the wall, so the thickness of the parison can be adjusted overall from the circumferential direction to create the ideal Moreover, since it is not possible to form a gap on the inner surface of the lower end of the die as in the conventional case, it is possible to eliminate the need for a closing plate to close the gap.

(2) Since the end shape of the connecting portion of the segment is simple, the segment is easy to manufacture, and the thickness adjustment ring can be easily adjusted.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional side view of a parison head equipped with a wall thickness adjusting device of the present invention, FIG. 2 is a view taken in the direction of the - arrow in FIG. The figures are a schematic cut-away side view of a parison head equipped with a conventional wall thickness adjustment device, FIG. 5 is an enlarged view taken along the - line in FIG. 4, FIG. The figure is an explanatory diagram of segments. 2 is a die, 3 is a core, 5 is a slit, 17 is a groove, 18 is an adjustment ring, 19 is a segment, 19
a is a curved protrusion, 19b is a curved seat, 20 is a pin, 2
1a to 21d are cylinders, and 22a to 22d are rods.

Claims (1)

[Claims] 1. In a blow molding machine that injects a parison from a slit formed between a core disposed at the center of the lower end of the parison head body and a die provided on the outer periphery of the core, Provided with an annular groove, divided into four or more parts, and provided with a curved protrusion and a curved seat on the top and bottom of one end,
Further, a wall thickness adjustment ring is disposed in the groove, in which arc-shaped segments each having a curved seat and a curved projection that can be fitted to the curved projection and the curved seat are connected with pins at the top and bottom of the other end, A device for adjusting wall thickness of a parison in a blow molding machine, characterized in that a rod of a push/pull device is connected to each pin connecting portion of the thickness adjustment ring by penetrating the die from the outside.