Blow molding die and blow molding apparatus

Abstract

A blow molding die (1) comprises a pair of blow cavity split molds (10) and a pair of blow cavity split mold holders (30). The blow cavity split mold holders (30) each comprise an inner wall (34) and a pair of rims (36a, 36b) that are disposed so as to hold the inner wall (34) therebetween. A first rim (36a), which is one of the rims, is provided with a projection member (38a) that protrudes toward the inside of the blow cavity split mold (30). A second rim (36b), which is the other of the rims, is provided with a pressing member (38b) that presses the blow cavity split mold (10) toward the blow cavity split mold holder (30).

Description

Technical Field

[0001] The present invention relates to a blow molding die and a blow molding apparatus.

Background Art

[0002] Patent Document 1 discloses a blow mold including a half mold, a half mold holder, and a quick coupling device. Patent Document 2 discloses an apparatus for attaching a blow molding die segment, which includes a supporting element and a locking element for the blow molding die segment.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a molding apparatus that fixes a cavity split mold to a holder and blow-molds a container, if the cavity split mold is displaced with respect to the holder, there is a risk of deterioration in the quality of the molded container, and there is also a risk of progress in wear of the mold parts. For example, in a conventional rotary blow molding apparatus, since the cavity split mold is not usually set at a high temperature, a technique for suppressing displacement of the cavity split mold in consideration of thermal expansion has not been reported.

[0005] An object of the present invention is to provide a blow molding die and a blow molding apparatus that can hold a thermally expanding blow cavity split mold at an appropriate position of a blow cavity split mold holder and can stably blow-mold a container.

Means for Solving the Problems

[0006] A blow molding die according to one aspect of the present invention is: A blow molding die comprising a pair of blow cavity split molds and a pair of blow cavity split mold holders, each holding one of the blow cavity split molds, The blow cavity split mold holder has an inner wall that forms a recess for housing the blow cavity split mold, and a pair of edges that are positioned to sandwich the inner wall when the blow cavity split mold holder is viewed from a direction perpendicular to the parting surface of the blow cavity split mold. A protruding member is provided on one of the first edges of the aforementioned edge portion, which protrudes toward the inside of the blow cavity split mold holder. A pressing member is provided on the other second edge of the aforementioned edge, which presses the blow cavity split mold toward the blow cavity split mold holder. This is a mold for blow molding.

[0007] A blow molding apparatus according to one aspect of the present invention, A blow molding apparatus for blow molding resin containers, comprising a blow molding section, The blow molding section comprises the blow molding die described above. This is a blow molding machine. [Effects of the Invention]

[0008] According to the present invention, a blow molding die and blow molding apparatus can be provided that can hold a thermally expanding blow cavity split mold in the correct position in the blow cavity split mold holder, thereby enabling stable blow molding of containers. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows a blow molding die according to an embodiment. [Figure 2] This is a schematic diagram of the section A-A' in Figure 1. [Figure 3] This is a schematic diagram of the B-B' section in Figure 1. [Figure 4] This is a diagram showing a pressing member according to an embodiment. [Figure 5] This diagram shows the blow cavity split mold being attached to the blow cavity split mold holder. [Figure 6] This figure shows the blow cavity split mold and blow cavity split mold holder when the blow molding die has been heated to the blow molding temperature. [Figure 7] This figure shows a blow molding apparatus according to an embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. Note that the dimensions of the components shown in these drawings may differ from the actual dimensions of the components for the sake of explanation.

[0011] Figure 1 shows a blow molding die 1 according to this embodiment. The blow molding die 1 comprises a pair of blow cavity split molds 10 and a pair of blow cavity split mold holders 30, each holding one of the blow cavity split molds 10. The blow molding die 1 can be used in a two-step (cold parison) rotary blow molding apparatus and is configured to switch between a closed mold state and an open mold state by an opening and closing mechanism. The blow molding die 1 is configured to mold a resin container by introducing blow air in a closed mold state containing a resin preform. In detail, the blow molding die 1 defines a cavity corresponding to the shape of the container to be molded by a bottom mold (not shown) and a blow cavity split mold 10. The container is molded by introducing blow air from a blow core (not shown) into the preform contained in the cavity.

[0012] In the pair of blow cavity split molds 10 and the pair of blow cavity split mold holders 30, the configurations of each split mold and each holder are the same. In the following description, the configurations of one blow cavity split mold 10a and one blow cavity split mold holder 30a will be described. FIG. 1 shows a state of viewing the blow mold 1 in a direction orthogonal to the parting surface P of the blow cavity split mold 10a. In the present embodiment, the "orthogonal" does not mean strictly limited to a mode of intersecting at an angle of 90°, and may include, for example, a mode of intersecting within a range of 90° ± 5°. The blow mold 1 shown in FIG. 1 is used for blow molding of a container defining a central axis X. The blow cavity split mold 10a is housed inside the blow cavity split mold holder 30a.

[0013] Here, referring to FIGS. 1, 2, and 3, the blow cavity split mold holder 30a will be described. FIG. 2 is a schematic cross-sectional view taken along the line A-A' of FIG. 1. FIG. 3 is a schematic cross-sectional view taken along the line B-B' of FIG. 1. The blow cavity split mold holder 30a has a substantially semi-cylindrical inner wall 34 that forms a recess 32 for housing the blow cavity split mold 10a inside. The blow cavity split mold holder 3 reflects a pair of edge portions 36a and 36b that are positioned so as to sandwich the inner wall 34 (recess 32) when viewing the blow cavity split mold holder 30a in a direction orthogonal to the parting surface P of the blow cavity split mold 10a. The pair of edge portions 36a and 36b are located at the circumferential edge of the inner wall 34 of the blow cavity split mold 10a. The pair of edge portions 36a and 36b extend parallel to the central axis X.

[0014] A protruding member 38a that protrudes toward the inside of the blow cavity split mold holder 30a is provided on one of the edge portions, the first edge portion 36a. The protruding member 38a may be composed of a plate-like member fastened to the first edge portion 36a, and may have a protruding portion 38aa that protrudes from the first edge portion 36a toward the inside of the blow cavity split mold holder 30a in a part thereof. In the example shown in FIG. 1, the protruding member 38a is composed of a plate-like member and has at least two protruding portions 38aa arranged in the direction in which the central axis X extends. On the other second edge portion 36b of the edge portion, a pressing member 38b is provided. The pressing member 38b presses the blow cavity split mold 10a toward the blow cavity split mold holder 30a. The pressing member 38b is provided so as to be rotatable about a rotation axis orthogonal to the surface of the second edge portion 36b. Further, the rotation axis of the pressing member 38b may be provided so as to be orthogonal to the parting surface P as well. Thereby, the pressing member 38b is configured to be able to switch between a pressing position protruding toward the inside of the blow cavity split mold holder 30a and a retracted position not protruding toward the inside of the blow cavity split mold holder 30a.

[0015] Here, the pressing member 38b will be described in detail with reference to FIG. 4. FIG. 4 is a diagram showing the pressing member 38b. The pressing member 38b shown in FIG. 4 has a pressing portion 38ba that presses the blow cavity split mold 10a toward the blow cavity split mold holder 30a, a housing 38bb that houses the pressing portion 38ba, and a fastening portion 38bc that is fastened to the second edge portion 36b. In the example shown in FIG. 4, the pressing portion 38ba is a plunger pin composed of a biasing member such as a spring and a pin-shaped member. The tip of the pressing portion 38ba is configured to be able to enter and exit the housing 38bb. The pin-shaped member biased by the biasing member contacts the blow cavity split mold 10a and presses the blow cavity split mold 10a toward the blow cavity split mold holder 30a (FIG. 3).

[0016] Here, returning to FIGS. 1, 2, and 3, the blow cavity split mold holder 30a will be described. On the inner wall 34 of the blow cavity split mold holder 30a, a pin-shaped positioning member 40 protruding from the surface thereof is provided. The positioning member 40 is a member that contacts and positions the blow cavity split mold 10a. In the illustrated example, the positioning member 40 is provided slightly offset from the center in the circumferential direction of the inner wall 34. Also in the illustrated example, at least two positioning members 40 are provided side by side in the direction in which the central axis X extends.

[0017] Next, the blow cavity split mold 10a will be described with reference to Figures 1, 2, and 3. The blow cavity split mold 10a has a substantially cylindrical outer wall 12 that at least partially contacts the inner wall 34 of the blow cavity split mold holder 30a. The outer wall 12 of the blow cavity split mold 10a is provided with a groove 14 that extends in the circumferential direction. One first end 14a of the groove 14 in the circumferential direction is open at the edge of the outer wall 12. The first end 14a is open on the side of the first edge 36a of the blow cavity split mold holder 30a, and the other second end 14b of the groove 14 in the circumferential direction is closed without extending to the edge of the outer wall 12. In the illustrated example, the second end 14b is located approximately in the circumferential center of the outer wall 12. Also in the illustrated example, there are at least two grooves 14 arranged in the direction extending along the central axis X. The depth of the groove 14 may be less than the protrusion amount of the positioning member 40.

[0018] Recesses 16a and 16b are provided on each of the circumferential edges of the outer wall 12 of the blow cavity split mold 10a. The protruding portion 38aa of the protruding member 38a of the blow cavity split mold holder 30a is positioned in the first recess 16a, which is provided on the first edge 36a side of the blow cavity split mold holder 30a. The pressing portion 38ba of the pressing member 38b of the blow cavity split mold holder 30a is positioned in the second recess 16b, which is provided on the second edge 36b side of the blow cavity split mold holder 30a. The pressing portion 38ba of the pressing member 38b of the blow cavity split mold holder 30a contacts the second recess 16b of the blow cavity split mold holder 30a, pressing the blow cavity split mold 10a against the positioning member 40.

[0019] Here, with reference to Figures 3 and 5, an embodiment of attaching the blow cavity split mold 10a to the blow cavity split mold holder 30a will be described. Figure 5 shows the blow cavity split mold 10a attached to the blow cavity split mold holder 30a. In the state shown in Figure 5, the pressing member 38b of the blow cavity split mold holder 30a is in a retracted position, not protruding inward from the blow cavity split mold holder 30a. With the pressing member 38b in the retracted position, the blow cavity split mold 10a can be accommodated in the recess 32 of the blow cavity split mold holder 30a from the second edge 36b side of the blow cavity split mold holder 30a. Furthermore, by passing the positioning member 40 provided on the inner wall 34 of the blow cavity split mold holder 30a through the groove 14 provided on the outer wall 12 of the blow cavity split mold 10a, the blow cavity split mold 10a can be smoothly accommodated in the recess 32 of the blow cavity split mold holder 30a.

[0020] When the positioning member 40 comes into contact with the second end portion 14b of the groove portion 14 of the blow cavity split mold 10a, the pressing member 38b is rotated to a pressing position that protrudes inward from the blow cavity split mold holder 30a, thereby holding the blow cavity split mold 10a in the blow cavity split mold holder 30a (Figure 3). By switching the pressing member 38b to the pressing position, the pressing portion 38ba of the pressing member 38b of the blow cavity split mold holder 30a comes into contact with the second recess 16b of the blow cavity split mold holder 30a, pressing the blow cavity split mold 10a against the positioning member 40. At this time, the second end portion 14b of the groove 14 of the blow cavity split mold 10a and the positioning member 40 are in contact at the center in the circumferential direction of the outer wall 12 of the blow cavity split mold 10a and the inner wall 34 of the blow cavity split mold holder 30a, respectively.

[0021] Next, the state of the blow molding die 1 before and after heating will be described with reference to Figures 3 and 6. Figure 6 shows the blow cavity split mold 10a and blow cavity split mold holder 30a when the blow molding die 1 has been heated to the blow molding temperature. Figure 3 shows the state when the blow molding die 1 has not been heated. In this embodiment, the blow molding die 1 is set to a high temperature when blow molding a container. Here, "high temperature" refers to states such as 60°C or higher, 80°C or higher, 100°C or higher, 130°C or higher, 150°C or higher, 180°C or higher, and 250°C or lower. In such high temperature states, the blow cavity split mold 10a may undergo thermal expansion.

[0022] The blow molding die 1 is configured such that, in an unheated state (Figure 3), the blow cavity split mold 10a is pressed by the pressing member 38b while a gap Sa exists between the blow cavity split mold 10a and the protruding member 38a. Furthermore, in a heated state (Figure 6), the blow molding die 1 is configured such that, in an heated state (Figure 6), the blow cavity split mold 10a is pressed by the pressing member 38b while the blow cavity split mold 10a and the protruding member 38a are in contact.

[0023] In this embodiment, the blow cavity split mold 10a is positioned by the positioning member 40 of the blow cavity split mold holder 30a contacting the second end portion 14b of the groove 14. The protruding member 38a is provided on the blow cavity split mold holder 30a such that a gap Sa exists between the first recess 16a of the blow cavity split mold 10a and the protruding portion 38aa of the protruding member 38a when it is not heated. The protruding member 38a is provided on the blow cavity split mold holder 30a such that the first recess 16a of the blow cavity split mold 10a and the protruding portion 38aa of the protruding member 38a come into contact when it is heated.

[0024] Furthermore, the pressing member 38b is provided on the blow cavity split mold holder 30a such that a gap Sb exists between the second recess 16b of the blow cavity split mold 10a and the housing 38bb of the pressing member 38b when the blow cavity split mold holder 30a is not heated. Then, when the blow cavity split mold holder 30a is heated, the pressing portion 38ba is housed in the housing 38bb, and the pressing member 38b is provided on the blow cavity split mold holder 30a such that the second recess 16b of the blow cavity split mold 10a and the housing 38bb of the pressing member 38b come into contact.

[0025] Next, with reference to Figure 7, the blow molding apparatus according to this embodiment will be described. Figure 7 is a diagram showing the blow molding apparatus 100 according to this embodiment. The blow molding apparatus 100 includes a blow molding section 110. The blow molding section 110 includes a blow molding die 1.

[0026] In detail, the blow molding apparatus 100 includes a preform supply chute 102, a preform heating unit 104, a preform supply wheel 106, a first blow molding rotary unit 110a, an intermediate rotary unit 120, a second blow molding rotary unit 110b, a molded product removal wheel 122, and a molded product removal rail 124. Note that various configurations listed here can be appropriately adopted from those disclosed in Japanese Patent Application Publication No. 2010-064453, and a detailed explanation is omitted. In this embodiment, the blow molding die 1 is configured to mold one container, and the transport means is adjusted accordingly.

[0027] In this embodiment, at least one of the first blow molding rotary section 110a and the second blow molding rotary section 110b may be equipped with a blow molding die 1. In this embodiment, at least one of the first blow molding rotary section 110a and the second blow molding rotary section 110b may blow mold the molded product at a high temperature.

[0028] [Effects / Effects] The blow molding die 1 described above comprises a pair of blow cavity split molds 10 and a pair of blow cavity split mold holders 30. A pair of edges 36a and 36b are located on either side of the inner wall 34 of the blow cavity split mold holder 30. A protruding member 38a is provided on one first edge 36a, and a pressing member 38b is provided on the other second edge 36b. The pressing member 38b presses the blow cavity split mold 10 toward the blow cavity split mold holder 30, so that even if the blow cavity split mold 10 expands due to heat, its position does not shift significantly. The thermally expanded blow cavity split mold 10 then comes into contact with the protruding member 38a and is held in the correct position by the blow cavity split mold holder 30 (Figure 6). This enables stable blow molding.

[0029] Furthermore, in the blow molding die 1 described above, when the blow cavity split mold 10 is not heated, a gap Sa exists between the blow cavity split mold 10 and the protruding member 38a while the blow cavity split mold 10 is pressed by the pressing member 38b (Figure 3). This allows the displacement of the blow cavity split mold 10 due to thermal expansion to be guided towards the protruding member 38a. Then, when the blow cavity split mold 10 and the protruding member 38a come into contact when the blow cavity split mold 10 is heated, the blow cavity split mold 10 can be held in the blow cavity split mold holder 30 in a more appropriate position.

[0030] Furthermore, in the blow molding die 1 described above, a positioning member 40 is provided on the inner wall 34 of the blow cavity split mold holder 30 to position the blow cavity split mold 10. As a result, the pressing member 38b presses the blow cavity split mold 10 against the positioning member 40, allowing the blow cavity split mold 10 to be held in the blow cavity split mold holder 30 in a more appropriate position.

[0031] Furthermore, in the blow molding die 1 described above, the positioning member 40 on the inner wall 34 of the blow cavity split mold holder 30 is in contact with the second end 14b of the groove 14 on the outer wall 12 of the blow cavity split mold 10. This allows the blow cavity split mold 10 to be held in the blow cavity split mold holder 30 in a more appropriate position. Moreover, by providing the outer wall 12 of the blow cavity split mold 10 with a groove 14 extending in the circumferential direction, for example, when replacing the blow cavity split mold 10 by releasing the pressure on the blow cavity split mold 10 by the pressing member 38b while the protruding member 38a is fixed, the groove 14 can be used as a passage for the positioning member 40, making it easy to attach and detach the blow cavity split mold 10 from the second edge 36b side where the pressing member 38b was located. This reduces the burden of cavity mold replacement work.

[0032] Furthermore, in the blow molding die 1 described above, the first end 14a of the groove 14 is open on the first edge 36a side of the blow cavity split mold holder 30. This allows for easy installation and removal of the blow cavity split mold 10 when replacing the blow cavity split mold 10 from the second edge 36b side, by using the groove 14 as a passage for the positioning member 40. This further reduces the burden of die replacement work.

[0033] Furthermore, in the blow molding die 1 described above, the pressing member 38b is configured to be switchable between a pressing position in which it protrudes toward the inside of the blow cavity split mold holder 30 and a retracted position in which it does not protrude toward the inside of the blow cavity split mold holder 30. This reduces the burden of cavity mold replacement work. Specifically, when replacing the cavity mold, the pressing member 38b can be switched to the retracted position to facilitate replacement, and after the cavity mold replacement work is completed, the pressing member 38b can be switched back to the pressing position to easily hold the blow cavity split mold 10 in the correct position on the blow cavity split mold holder 30.

[0034] Furthermore, with the blow molding apparatus 100, by providing the blow molding die 1, the blow cavity split mold 10, which undergoes thermal expansion, can be held in the correct position in the blow cavity split mold holder 30, thereby achieving stable blow molding.

[0035] Furthermore, the present invention is not limited to the embodiments described above, and can be freely modified and improved as appropriate. In addition, the material, shape, dimensions, numerical values, form, number, and placement of each component in the embodiments described above are arbitrary and not limited as long as they can achieve the present invention.

[0036] In the above embodiment, a configuration was described in which the pressing member 38b is rotatable, allowing switching between the pressing position and the retracted position. However, the pressing member 38b may also be made into a sliding type to allow switching between the pressing position and the retracted position.

[0037] In the above embodiment, a double-blow blow molding apparatus 100 comprising a first blow molding rotary section 110a and a second blow molding rotary section 110b has been described, but a blow molding die 1 may also be used in a single-blow blow molding apparatus.

[0038] In the above embodiment, a configuration in which two protrusions 38aa and two pressing members 38b are provided was described, but the number of these can be changed as appropriate. Also, in the above embodiment, a configuration in which two grooves 14 and two positioning members 40 are provided was described, but the number of these can be changed as appropriate. Providing two or more grooves 14 and positioning members 40 is preferable because it allows the thermally expanding blow cavity split mold 10 to be held in a more appropriate position relative to the blow cavity split mold holder 30.

[0039] This application is based on Japanese Patent Application No. 2021-77581, filed on 30 April 2021, which is incorporated by reference in its entirety. All references incorporated herein are incorporated as a whole. [Explanation of Symbols]

[0040] 1: Blow molding die, 10, 10a: Blow cavity split mold, 12: Outer wall, 14: Groove, 14a: First end, 14b: Second end, 16a: First recess, 16b: Second recess, 30, 30a: Blow cavity split mold holder, 32: Recess, 34: Inner wall, 36a: First edge, 36b: Second edge, 38a: Protruding member, 38aa: Protruding part, 38b: Pressing member, 38ba: Pressing part, 38bb: Housing, 38bc: Fastening part, 4 0: Positioning member, 100: Blow molding apparatus, 102: Preform supply chute, 104: Preform heating section, 106: Preform supply wheel, 110: Blow molding section, 110a: First blow molding rotary section, 110b: Second blow molding rotary section, 120: Intermediate rotary section, 122: Molded product removal wheel, 124: Molded product removal rail, P: Parting surface, Sa: Gap, Sb: Gap, X: Center axis

Claims

1. A blow molding die comprising a pair of blow cavity split molds and a pair of blow cavity split mold holders each holding one of the blow cavity split molds, The blow cavity split mold holder has an inner wall that forms a recess for housing the blow cavity split mold, and a pair of edges that are positioned to sandwich the inner wall when the blow cavity split mold holder is viewed from a direction perpendicular to the parting surface of the blow cavity split mold. A protruding member is provided on one of the first edges of the aforementioned edge portion, which protrudes toward the inside of the blow cavity split mold holder. A pressing member is provided on the other second edge of the aforementioned edge, which presses the blow cavity split mold toward the blow cavity split mold holder. In the state where the blow cavity split mold has not been heated, the blow cavity split mold is pressed by the pressing member, and a gap exists between the blow cavity split mold and the protruding member. In the heated state where the blow cavity split mold has been heated to the blow molding temperature, the blow cavity split mold is pressed by the pressing member, and the blow cavity split mold and the protruding member are in contact. Blow molding die.

2. The blow cavity split mold has an outer wall that at least partially contacts the inner wall of the blow cavity split mold holder, The inner wall of the blow cavity split mold holder is provided with a positioning member that contacts the outer wall of the blow cavity split mold to position the blow cavity split mold. The pressing member presses the blow cavity splitter against the positioning member. A blow molding die according to claim 1.

3. The inner wall of the blow cavity split mold holder and the outer wall of the blow cavity split mold are substantially cylindrical. The outer wall of the blow cavity split mold is provided with grooves extending in the circumferential direction. One of the first ends of the groove in the circumferential direction is open at the edge of the outer wall. The other second end of the groove in the circumferential direction is closed without extending to the edge of the outer wall. The second end is in contact with the positioning member. A blow molding die according to claim 2.

4. A blow molding die comprising a pair of blow cavity split molds and a pair of blow cavity split mold holders each holding one of the blow cavity split molds, The blow cavity split mold holder has an inner wall that forms a recess for housing the blow cavity split mold, and a pair of edges that are positioned to sandwich the inner wall when the blow cavity split mold holder is viewed from a direction perpendicular to the parting surface of the blow cavity split mold. A protruding member is provided on one of the first edges of the aforementioned edge portion, which protrudes toward the inside of the blow cavity split mold holder. A pressing member is provided on the other second edge of the aforementioned edge, which presses the blow cavity split mold toward the blow cavity split mold holder. The blow cavity split mold has an outer wall that at least partially contacts the inner wall of the blow cavity split mold holder, The inner wall of the blow cavity split mold holder is provided with a positioning member that contacts the outer wall of the blow cavity split mold to position the blow cavity split mold. The pressing member presses the blow cavity splitter against the positioning member. The inner wall of the blow cavity split mold holder and the outer wall of the blow cavity split mold are substantially cylindrical. The outer wall of the blow cavity split mold is provided with grooves extending in the circumferential direction. One of the first ends of the groove in the circumferential direction is open at the edge of the outer wall. The other second end of the groove in the circumferential direction is closed without extending to the edge of the outer wall. The second end is in contact with the positioning member. Blow molding die.

5. The first end of the groove is open on the first edge side of the blow cavity split mold holder. A blow molding die according to claim 3 or claim 4.

6. The pressing member is configured to be switchable between a pressing position in which it protrudes toward the inside of the blow cavity split mold holder and a retracted position in which it does not protrude toward the inside of the blow cavity split mold holder. A blow molding die according to any one of claims 1 to 5.

7. A blow molding apparatus for blow molding resin containers, comprising a blow molding section, The blow molding section comprises a blow molding die according to any one of claims 1 to 6. Blow molding machine.

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