JPH0345692B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to an injection stretch blow blow molding apparatus.

(b) Prior Art A conventional injection stretch blow molding apparatus is disclosed in, for example, Japanese Unexamined Patent Publication No. 87133/1983. This injection stretch blow molding apparatus adjusts the temperature of a parison injection molded in a parison molding section in a temperature control section, then stretch blow molds it in a stretch blow molding section, and delivers the obtained hollow molded product from a blow molded product discharge section. It is designed to be discharged. If multiple rows of parisons are arranged in the parison transport direction in order to increase the number of molded parts, for example, the result will be as shown in Fig. 5 (in this example, the number of molded parts is eight and they are arranged in two rows). . In this case, the spacing in the parison transfer direction, that is, the pitch in the parison transfer direction, is the same dimension A for all of the parison molding section, first temperature adjustment section, second temperature adjustment section, stretch blow molding section, and hollow molded product discharge section. . This dimension A is set to a value determined in the stretch blow molding section. That is, as shown in FIGS. 6 and 7, the dimension A is determined from the mold opening amount l of the blow molding die, which is set to be larger than the outer diameter d of the hollow molded product in the stretch blow molding section. The pitches in the parison transfer direction of other parts are made to match the dimension A determined in this stretch blow-molded part.

(c) Problems to be solved by the invention Since the outer diameter of a stretch-blow-molded hollow molded product is generally 2.5 to 3.5 times the outer diameter of the parison, the dimension A determined in the stretch-blow-molded part is the same as that of the parison-molded part. The pitch in the parison transfer direction is excessive. For this reason, the hot runner in the injection mold becomes longer than necessary, the amount of molten resin that stays in the hot runner increases, and a large thermal history acts on the resin material. For this reason, for example, the amount of acetaldehyde contained in the hollow molded product increases, and when the hollow molded product is used for filling foodstuffs, it has an adverse effect on odor, taste, etc. Furthermore, since the pitch of the injection mold in the parison transfer direction is larger than necessary, the injection mold becomes larger, and a correspondingly larger mold clamping device needs to be used. The present invention aims to solve the above problems.

(d) Means for Solving the Problems The present invention solves the above problems by providing a parison take-out device that takes out parisons from a parison molding section with a variable pitch mechanism that changes the pitch in the parison transfer direction. That is, the pitch in the parison transfer direction of the parison forming section of the injection stretch blow blow molding apparatus according to the present invention is made smaller than the pitch in the parison transfer direction of the stretch blow molding section, and the parison transfer direction pitch of the parison forming section is smaller than that of the stretch blow molding section. The take-out device has a mechanism for reducing the pitch in the parison transfer direction on the parison forming section side to match the pitch in the parison transfer direction in the parison forming section, and on the temperature control section side so as to match the pitch in the parison transfer direction in the stretch blow molding section. A variable pitch mechanism is provided to increase the pitch. The pitch variable mechanism is
It can be configured by a plurality of parison receiving plates, a stopper that defines the relative positional relationship of the parison receiving plates, a spring between the parison receiving plates, a drive mechanism (for example, an air cylinder) that can press the parison receiving plates, etc. .

(e) Effect With the above-described configuration, the pitch of the parison take-out device in the parison transfer direction is reduced in the parison forming section and matches the pitch of the parison forming section in the parison transfer direction. In addition, the pitch in the parison transfer direction is expanded in the temperature control section and matches the pitch in the parison transfer direction of the temperature control section (this is the same as the pitch in the parison transfer direction of the stretch blow molding section). Therefore, the pitch in the parison transfer direction in the parison forming section can be set to be optimal, regardless of the pitch in the parison transfer direction in the stretch blow molding section. Therefore, the pitch in the parison transfer direction in the parison molding section can be set small, making it possible to downsize the injection mold and shorten the hot runner. As the hot runner becomes shorter, the amount of resin material remaining becomes smaller.
The thermal history acting on the resin material is reduced, making it possible to obtain higher quality hollow molded products.

(f) Example FIG. 1 shows a parison forming section 10 and a first temperature regulating section 12 of an injection stretch blow blow molding apparatus. The parison molding section 10 is provided with a mold clamping device having a fixed platen 14, a movable platen 16, and a tie bar 17, and a lower injection mold 18 and an upper injection mold 20 are attached to the fixed platen 14 and the movable platen 16, respectively. It is being Parison molding section 10 and first temperature adjustment section 12
A parison extraction device 22 is provided between the two.
As shown in FIG. 2, the parison extraction device 22 is
It has a first parison receiving plate 26 and a second parison receiving plate 28 which are movable in the horizontal direction guided by two guide rods 24. Four temperature adjusting cylinders 30 are arranged in one row on the first parison receiving plate 26, and four temperature adjusting cylinders 31 are similarly arranged in one row on the second parison receiving plate 28. (The temperature adjustment cylinder 30 and the temperature adjustment cylinder 31 are the same). The first parison receiving plate 26 and the second parison receiving plate 28 are guided by the guide rod 24 and are movable relative to each other. It is regulated by a stopper 34. The expansion direction stopper 32 is constituted by a nut screwed into the tip of a piston rod 38 of an air cylinder 36 (drive mechanism) passing through a hole 28a of the second parison receiving plate 28. Note that a male thread is formed on the outer periphery of the piston rod 38. Further, the reduction direction stopper 34 is constituted by a cylindrical member having a predetermined length and having a female thread corresponding to the male thread of the piston rod 38. Note that the air cylinder 36
The piston rod 38 is connected to the reduction direction stopper 34.
and the nut 40, the first parison receiving plate 26
It is connected to the first parison receiving plate 26 by sandwiching it. First parison receiving plate 26
A spring 42 is provided on the outer periphery of the guide rod 24 between the parison receiving plate 26 and the second parison receiving plate 28, and applies a force in the direction of moving the first parison receiving plate 26 and the second parison receiving plate 28 away from each other. . The support members 44 and 46 on both sides supporting the guide rod 24 are provided with a positioning member 48 and a positioning member 50 for stopping the second parison receiving plate 28 and the first parison receiving plate 26, respectively.

Next, the operation of this embodiment will be explained. Second
In the figure, the parison take-out device 22 is connected to the first temperature control section 12.
It is shown stopped on the side. That is, the air cylinder 36 is retracting the piston rod 38, and the first parison receiving plate 26 is in contact with the positioning member 5.
It touches 0 and stops. In this state, the second parison receiving plate 28 is pushed rightward in FIG. 2 by the force of the spring 42, and is pressed against the expansion direction stopper 32. Therefore, the distance between the center of the temperature control tube 30 and the center of the temperature control tube 31, ie, the pitch in the parison transfer direction, is dimension A. When the air cylinder 36 extends the piston rod 38 from this state, the first parison receiving plate 26 moves to the right in FIG. Second
Since the parison receiving plate 28 also receives force via the spring 42, the pitch in the parison transfer direction is
The second parison receiving plate 28 also moves to the right while holding it. When the piston rod 38 further extends and the second parison receiving plate 28 contacts the positioning member 48, the second parison receiving plate 28 stops.
However, the first parison receiving plate 26
2 and further moves to the right by dimension C, and stops when the right end surface of the reduction direction stopper 34 in the figure contacts the second parison receiving plate 28. This state is shown in FIG. In the state shown in FIG. 3, the pitch in the parison transfer direction is dimension B (B=A-C). Dimension B is made equal to the pitch in the parison transfer direction of the injection mold (dimension B' in FIG. 1).
Therefore, eight parisons 52 can be received simultaneously from the upper injection mold 20 in the state shown in FIG. When the parison 52 is accommodated in the temperature control tubes 30 and 31, the air cylinder 36 retracts the piston rod 38 and begins to move the first parison receiving plate 26 to the left in FIG. When the first parison receiving plate 26 moves by the dimension C and the pitch in the parison transfer direction becomes the dimension A, the expansion direction stopper 32 comes into contact with the second parison receiving plate 28, and the second parison receiving plate 28 is moved by the first parison receiving plate. 26 to the left. Thus, the first
When the parison receiving plate 26 moves to a position where it contacts the positioning member 50, it returns to the state shown in FIG. In this state, the pitch in the parison transfer direction is dimension A as described above. In this state, the eight parisons 52 are held by a parison moving device (not shown), and the second parison 52 is held by a parison moving device (not shown).
After being transferred to the temperature adjustment section 54 and further temperature-controlled, it is transferred to the stretch blow molding section 56 where it is stretch blow molded, and then the hollow molded article is discharged from the blow molded article discharge section 58. The pitches in the parison transfer direction in the second temperature control section 54, stretch blow molding section 56, and hollow molded product discharge section 58 are all dimension A as shown in FIG. They are transported sequentially depending on the direction. Dimension A is the stretch blow molding part 56
This value is determined by the amount of opening of the blow molding die.

As mentioned above, the pitch dimension B in the parison transfer direction in the parison forming section 10 is
It can be set independently of the pitch dimension A in the parison transfer direction in No. 2. Therefore, the lower injection mold 18 and the upper injection mold 20 can be designed so that the dimension B has an optimal value for molding the parison 52 of a predetermined size. As a result, the length of the hot runner in the injection mold becomes shorter, and less resin material stays in the hot runner, so the thermal history acting on the resin material is also reduced, resulting in a higher quality hollow molded product, such as acetaldehyde containing A small quantity of hollow molded products can be obtained.
Moreover, the lower injection mold 18 and the upper injection mold 20 can be made smaller, and the mold clamping device can also be made smaller accordingly. By changing the length of the reduction direction stopper 34, the parison transfer direction pitch dimension B can be adjusted as desired, and by changing the position of the enlargement direction stopper 32, the parison transfer direction pitch dimension A can be adjusted as desired.
can also be adjusted.

(G) Effects of the Invention As explained above, according to the present invention, since the pitch in the parison transfer direction of the parison take-out device is made variable, it is possible to shorten the hot runner in the injection mold and produce high-quality hollow molded products. In addition, it becomes possible to downsize the injection mold and the mold clamping device. In addition, it becomes possible to unify the pitch in the parison transfer direction of the injection molds for molding parisons for obtaining hollow molded products of different sizes, thereby making it possible to standardize the injection molds. Further, by making the expansion direction stopper and the contraction direction stopper adjustable, the range of application of the parison extraction device is expanded.

[Brief explanation of drawings]

FIG. 1 is a front view of an injection stretch blow blow molding apparatus according to the present invention (a view taken along the - line in FIG. 2);
FIG. 2 is a plan view of the parison take-out device of the injection stretch blow blow molding machine shown in FIG. FIG. 4 is a diagram schematically showing the entire injection stretch blow molding apparatus; FIG. 5 is a diagram schematically showing a conventional injection stretch blow blow molding apparatus; FIG. 6 is a diagram showing a conventional blow molding die in an open state, and FIG. 7 is a sectional view taken along the line - in FIG. 6. DESCRIPTION OF SYMBOLS 10... Parison molding part, 12... First temperature adjustment part, 14... Fixed plate, 16... Movable plate, 18...
... lower injection mold, 20 ... upper injection mold, 22 ... parison take-out device, 24 ... guide rod, 26 ...
First parison receiving plate, 28...Second parison receiving plate, 30...Temperature adjustment cylinder, 32...Enlargement direction stopper, 34...Reduction direction stopper, 36...Air cylinder (drive mechanism), 38...Piston rod ,
40...Natsuto, 42...Spring, 44...
Supporting member, 46... Supporting member, 48... Positioning member, 50... Positioning member, 52... Parison, 54... Second temperature control section, 56... Stretch blow molding section, 58... Hollow molded product discharge Department.

Claims (1)

[Scope of Claims] 1. An injection stretch blow blow molding apparatus in which a parison molded in a parison molding section is transferred to a temperature adjustment section to adjust the temperature, and then transferred to a stretch blow molding section to perform stretch blow molding, In the parison molding section, temperature control section, and stretch blow molding section, there is a gap in the parison transfer direction (hereinafter referred to as "parison transfer direction pitch").
Multiple parisons are molded at the same time,
In an injection stretch blow molding apparatus that performs temperature control and stretch blow molding, the pitch in the parison transfer direction of the parison forming section is smaller than the pitch in the parison transfer direction of the stretch blow molding section, so that the parison is transferred from the parison forming section to the temperature control section. The parison take-out device that transfers the parison is designed to reduce the pitch in the parison transfer direction on the parison forming section side to match the pitch in the parison transfer direction in the parison forming section, and on the temperature control section side to reduce the pitch in the parison transfer direction in the stretch blow molding section. An injection stretch blow blow molding apparatus characterized by being provided with a variable pitch mechanism that expands to match the pitch. 2. The pitch variable mechanism includes a plurality of parison receiving plates that are relatively movable in the parison transfer direction, and an expansion direction mechanism that prevents the pitch between each parison receiving plate from becoming larger than the pitch in the parison transfer direction of the stretch blow molding section. a stopper, a reduction direction stopper that prevents the pitch between each parison receiving plate from becoming smaller than the pitch in the parison transfer direction of the parison forming section, and a spring that applies a force in a direction to enlarge the pitch between each parison receiving plate. , a drive mechanism that moves the entire parison receiving plate between the parison forming section and the temperature control section, and applies a pressing force between each parison receiving plate in the parison forming section. The injection stretch blow blow molding apparatus described in 2. 3 The enlargement direction stopper and the reduction direction stopper are
The injection stretch blow blow molding apparatus according to claim 2, wherein the fixing position is adjustable.