Injection blow molding machines and injection molding systems

Abstract

To provide a mold device capable of molding a container-shaped molded product having a protrusion formed on an outer surface of an opening end portion.SOLUTION: There is provided a mold device 101, comprising: an injection molding mold 111 having an injection side concave mold portion 112; a blow molding mold 121 having a blowing-side concave mold portion 122; and an intermediate mold 131 having a convex mold portion 132 that is disposed in the injection side concave mold portion 112 or the blowing side concave mold portion 122 in a mold clamped state. In the clamped state, an injection molding cavity 141 defined between the injection side concave mold portion 112 and the convex mold portion 132 has a shape corresponding to a container-shaped preform 201 having an opening end portion 203, and a blow molding cavity 151 defined between the blowing side concave mold portion 122 and the convex mold portion 132 has a shape corresponding to a container-shaped molded product 211 having an opening end portion 213 with a protrusion 215 formed on the outer surface.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a mold device and an injection molding system used in injection blow molding. [Background technology]

[0002] Injection blow molding is sometimes performed by attaching a predetermined mold assembly to an injection blow molding machine, which may include an injection mold having an injection-side concave mold portion, a blow mold having a blow-side concave mold portion, and an intermediate mold having a convex mold portion that is placed within the injection-side concave mold portion or the blow-side concave mold portion in a clamped state.

[0003] In injection blow molding using an injection blow molding machine, an injection molding cavity is defined between the injection-side concave and convex mold portions in a clamped state, and molding material is injected into this injection molding cavity to form a preform. Then, a blow molding cavity is defined between the blow-in side concave and convex mold portions in a clamped state, and the preform placed in the blow molding cavity is expanded by supplying a fluid such as air to form a molded product.

[0004] A related technique is described in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-167579 Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-mentioned injection blow molding, there is a need to be able to mold a container-shaped molded product having a protruding portion, such as a threaded portion, formed on the outer surface of the open end.

[0007] The present invention addresses these issues and aims to provide a mold apparatus and an injection molding system that can mold a container-shaped molded product having a protrusion formed on the outer surface of the opening end. [Means for solving the problem]

[0008] One mold device that can solve the above-mentioned problems comprises an injection molding mold having an injection-side concave mold portion, a blow molding mold having a blow-side concave mold portion, and an intermediate mold having a convex mold portion that is placed within the injection-side concave mold portion or the blow-side concave mold portion in a clamped state, wherein, in a clamped state, the injection molding cavity defined between the injection-side concave mold portion and the convex mold portion has a shape corresponding to a container-shaped preform having an open end, and the blow molding cavity defined between the blow-side concave mold portion and the convex mold portion has a shape corresponding to a container-shaped molded product having an open end with a protrusion formed on its outer surface. One injection molding system includes the above-mentioned mold apparatus and an injection blow molding machine to which the mold apparatus is attached. [Effects of the Invention]

[0009] The above-described mold device can mold a container-shaped molded product having a protrusion formed on the outer surface of the opening end. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing an example of an injection blow molding machine to which a mold device according to an embodiment of the present invention can be attached, together with the mold device. [Figure 2] 2 is a side view showing the mold device in the mold open state of FIG. 1 and a cross-sectional view taken along line II-II thereof. [Figure 3] 2 is a side view showing the mold clamping state of the mold device of FIG. 1 and a cross-sectional view taken along line II-II thereof. [Figure 4]1 is a side view showing a molded product and a preform molded by a mold device of one embodiment, with half of the product cut away in the radial direction across the central axis. FIG. [Figure 5] A cross-sectional view along the mold width direction showing the injection side concave portion of an injection molding mold, the blow side concave portion of a blow molding mold, and the convex portion of an intermediate mold provided in one embodiment of a mold device. [Figure 6] 6A to 6C are cross-sectional views along the mold width direction showing the injection-side concave mold portion, the blow-side concave mold portion, and the convex mold portion of the mold device of FIG. 5 in a clamped state and a mold open state, respectively. [Figure 7] A cross-sectional view along the mold width direction showing the injection side concave portion of the injection molding mold, the blow side concave portion of the blow molding mold, and the convex portion of the intermediate mold provided in a mold device of another embodiment. [Figure 8] 8 is a side view showing a molded article and a preform molded by the mold device of FIG. 7, with half of the part cut away in the radial direction across the central axis. [Figure 9] 8 is a cross-sectional view taken along the width direction of the mold, showing a convex mold portion of an intermediate mold included in the mold device of FIG. 7. [Figure 10] 8 is an enlarged cross-sectional view of a main portion of a blow-side concave mold portion of a blow molding mold and a convex mold portion of an intermediate mold provided in the mold apparatus of FIG. 7. [Figure 11] 10 is a cross-sectional view taken along the width direction of the mold, showing a modified example of the convex mold portion of the intermediate mold of the mold device or the injection-side concave mold portion of the injection mold. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The injection blow molding machine 1 illustrated in FIG. 1 is equipped with a mold apparatus 101 according to an embodiment of the present invention, and generally comprises an injection device 21 that melts molding material and injects it into the mold apparatus 101, a moving device 26 that moves the injection device 21 forward and backward relative to the mold apparatus 101, and a mold clamping device 31 that has a fixed platen 32a, a movable platen 32b, and an intermediate mold support frame 32c and opens and closes the mold apparatus 101 between a mold clamping state and a mold open state.

[0012] The injection blow molding machine 1 is used for injection blow molding. In injection blow molding, a molding material is injected into the injection molding cavity of a mold device 101 to form a preform, and then a gas such as air or other fluid is supplied to the preform in the blow molding cavity of the mold device 101 to expand the preform and form a molded product.

[0013] (Molding equipment) The mold device 101 includes an injection molding mold 111 attached to the fixed platen 32a side, a blow molding mold 121 attached to the movable platen 32b side, and an intermediate mold 131 supported by an intermediate mold support frame 32c between the injection molding mold 111 and the blow molding mold 121 and rotated by a rotation shaft portion 41 of the intermediate mold support frame 32c, as shown in Figures 2 and 3.

[0014] When the mold device 101 is attached to the injection blow molding machine 1 in this manner, the injection mold 111 has an injection-side concave mold portion 112 on the surface side facing the intermediate mold 131, as shown in Fig. 2(b). The blow mold 121 has a blow-side concave mold portion 122 on the surface side facing the intermediate mold 131, as shown in Fig. 3(b). The intermediate mold 131 also has convex mold portions 132 on both the surface facing the injection mold 111 and the surface facing the blow mold 121, which are disposed within the injection-side concave mold portion 112 or the blow-side concave mold portion 122 in a clamped state.

[0015] In the mold clamping state shown in Fig. 3, an injection molding cavity is defined between the injection-side concave mold portion 112 and the convex mold portion 132, where molding material is injected to form preform 201. After preform 201 is molded in the injection molding cavity, mold assembly 101 enters the mold open state as shown in Fig. 2, and convex mold portion 132, while holding preform 201, rotates inverted as intermediate mold 131 rotates by rotary shaft 41, and faces blow molding mold 121. Then, when mold assembly 101 enters the mold clamping state again as shown in Fig. 3, a blow molding cavity is defined between injection-side concave mold portion 122 and convex mold portion 132 holding preform 201. In the blow molding cavity, preform 201 expands as fluid is blown into it from the inside, becoming molded product 211. When the mold device 101 is in a clamped state, such injection molding and blow molding are performed simultaneously in the injection molding cavity and blow molding cavity defined by the injection side concave mold portion 112 or the blow side concave mold portion 122 and the convex mold portions 132 provided on both sides of the injection molding mold 111 side and the blow molding mold 121 side.

[0016] In the illustrated example, the injection-side concave mold portion 112 of the injection molding mold 111, the convex mold portion 132 of the intermediate mold 131, and the blow-side concave mold portion 122 of the blow molding mold 121 are each arranged two in the mold width direction and six in the height direction (the up and down direction in Figures 2(a) and 3(a)), for a total of twelve, but the numbers can be changed as appropriate.

[0017] Incidentally, the mold device 101 of this embodiment can mold a cylindrical container-shaped molded product 211 with a bottom as shown in Fig. 4(a). This molded product 211 can be obtained by molding a cylindrical container-shaped preform 201 with a bottom as shown in Fig. 4(b).

[0018] More specifically, the molded product 211 shown in Fig. 4(a) has a cylindrical main body 212 such as a cylinder, an open end 213 that is open at one end in the axial direction (the left-right direction in Fig. 4) of the cylindrical main body 212, and a sealed end 214 that is closed by a bottom 214a at the other end in the axial direction of the cylindrical main body 212. The outer surface of the open end 213 is provided with a protrusion 215 that protrudes from the outer surface and has, for example, a spiral shape that extends axially while winding in the circumferential direction on the outer surface. When the protrusion 215 is spiral-shaped, a cap (not shown) having a corresponding spiral groove on its inner surface can be attached and detached by screwing the cap onto the open end 213.

[0019] In this molded product 211, the cylindrical main body 212 includes a cylindrical trunk 212a, such as a cylinder, having a constant inner and outer diameter that continues from the closed end 214, and a tapered portion 212b whose inner and outer diameters gradually decrease toward the open end 213, connecting the trunk 212a to the open end 213. A ring-shaped flange 216, such as a circular ring, is formed at a portion of the open end 213 near the tapered portion 212b. The outermost end of the open end 213 in the axial direction is formed as a built-up portion 217 that is slightly thicker than the open end 213 and slightly protrudes toward the outer periphery. However, this built-up portion 217 is not considered to be part of the protrusion 215. Here, the region from the flange 216 to just before the outermost end on one end in the axial direction is defined as the open end 213. The molded product 211 may have any shape, as long as the protrusion 215 is formed on the outer surface of the open end 213.

[0020] 4(b), the preform 201 used in blow molding to obtain the molded article 211 has a cylindrical main body 202 whose inner and outer diameters gradually increase toward one axial end, an open end 203 that is open at one axial end of the cylindrical main body 202, and a closed end 204 that is closed by a bottom 204a at the other axial end of the cylindrical main body 202. In this preform 201, too, a cladding portion 207 is present at the outermost end of the open end 203, which is the outermost end in the axial direction, but the cladding portions 217 and 207 of the molded article 211 and the preform 201 may be omitted. The outer surface of the open end 203 of this preform 201, which does not include the cladding portion 207, is formed smoothly.

[0021] More specifically, the mold apparatus 101 capable of molding the preform 201 and molded article 211 described above has an injection mold 111, a blow mold 121, and an intermediate mold 131 configured as shown in FIG. 5. In the mold apparatus shown in FIG. 5, when the molds are clamped, as shown in FIG. 5 and FIG. 6(a), the convex mold portion 132 on one surface of the intermediate mold 131 is inserted into the injection-side concave mold portion 112 of the injection mold 111, defining an injection molding cavity 141 therebetween. At this time, the convex mold portion 132 on the other surface of the intermediate mold 131 is inserted into the blow-side concave mold portion 122 of the blow mold 121, defining a blow molding cavity 151 therebetween. Note that the preform 201 and molded article 211 are not shown in the drawings.

[0022] The injection molding cavity 141 is a space having a shape corresponding to the shape of the container-shaped preform 201 having the open end 203 described above. The blow molding cavity 151 is also a space having a shape corresponding to the shape of the container-shaped molded product 211 having the open end 213 with the protrusions 215 formed on the outer surface, as described above.

[0023] 5 and 6, a recessed portion 123 corresponding to the protruding portion 215 is formed on the inner peripheral surface of the blow-side concave portion 122, which corresponds to the outer surface of the molded article 211 in the blow molding cavity 151, at a location corresponding to the outer surface of the opening end 213 of the molded article 211. As a result, when the preform 201 held around the convex portion 132 in the blow molding cavity 151 expands due to the supply of fluid and is pressed against the inner peripheral surface of the blow-side concave portion 122, the recessed portion 123 forms a protruding portion 215 having a shape corresponding to the shape of the recessed portion 123 on the outer surface of the opening end 213 of the molded article 211. In this example, a spiral protrusion 215 is formed on the outer surface of the opening end 213 of the molded product 211, and a spiral recess 123 extending on the inner surface of the blowing side concave portion 122 is provided on the inner surface of the blowing side concave portion 122 to correspond to the protrusion 215.

[0024] The structure and shape of each mold of the mold apparatus 101 can be modified as appropriate. In the illustrated example, the injection molding mold 111 has a mold body 113 and a concave partition member 114 inserted and attached to the surface side of the mold body 113 facing the intermediate mold 131, as shown in FIG. 5. The concave partition member 114 is cylindrical with a bottom, and the portion exposed from the mold body 113 has larger inner and outer diameters than the portion inserted into the mold body 113. The injection-side concave portion 112 is provided inside this concave partition member 114. The surface area of ​​the inner peripheral surface of the injection-side concave portion 112, which corresponds to the outer surface of the open end 203 of the preform 201, is formed smoothly. The concave partition member 114 provided with the injection-side concave portion 112 does not have a split mold. The injection-side concave mold portion 112 is connected to the nozzle 22b of the cylinder 22 of the injection device 21 via a gate 115 provided at the deepest part of the injection-side concave mold portion 112 in the concave mold partitioning member 114. As a result, during injection molding, the molten molding material is supplied from the cylinder 22 to an injection molding cavity 141 defined within the injection-side concave mold portion 112.

[0025] The intermediate mold 131 has a core seat 131a, such as a plate-like one, attached to the rotary shaft 41, an annular base 134 provided on the core seat 131a, and a protruding portion 135, which is inserted into and attached to the base 134, protrudes from the base 134, and has an outer diameter that gradually decreases toward the tip. The protruding portion 135 has a curved tip surface. The base 134 and the protruding portion 135 form the convex portion 132. 5, in the mold clamped state, step portion 114a on the inner circumferential side of the portion of concave partitioning member 114 exposed from mold body 113 is aligned with step portion 134a on the outer circumferential side of base 134 of intermediate mold 131. Also, here, a space that forms buildup portion 207 of preform 201 is defined between annular groove portion 136 provided on the surface of base 134 facing injection mold 111 and step portion 114a of concave partitioning member 114.

[0026] In this embodiment, the blow molding mold 121 has a split mold 124 that can be opened and closed in the mold width direction. This allows the molded product 211, which has a larger bottom portion 214a in the axial direction, to be easily removed from the blow-side concave mold portion 122. A split mold opening / closing mechanism 62, which will be described later, defines a blow-side concave mold portion 122 shaped to match the outer shape of the molded product 211 inside the closed split mold 124, as shown in Figures 5 and 6. A step 124a that aligns with the step 134a of the base 134 is provided on the part of the split mold 124 that comes into contact with the base 134 of the intermediate mold 131 in the clamped state.

[0027] In the mold apparatus 101 described above, during blow molding, the open end 203 of the preform 201 is pressed against a recessed portion 123 provided on the inner peripheral surface of the blow-side recessed mold portion 122 by supplying a fluid to the inside of the open end 203, as shown in FIG. 5, thereby forming a protruding portion 215 at the open end 213 of the molded product 211. At this time, some of the molding material at the open end 203 of the preform 201 may fill the recessed portion 123, causing a sink mark, a depression from the inner surface, to occur on the inner surface of the open end 213 of the molded product 211. Such a molded product 211 may lack strength at the open end 213, where a cap or the like may be attached, resulting in poor quality.

[0028] To prevent this, as in the embodiment shown in Fig. 7, it is preferable to provide injection molding cavity 341 with thickened wall space 342, which is a partially wider space at least in a portion corresponding to opening end 403 of preform 401 shown in Fig. 8(b). Due to thickened wall space 342, preform 401 molded in injection molding cavity 341 has thickened wall portion 408, which is thicker than other portions such as cylindrical main body 402, at least in a portion of opening end 403. When blow molding is performed using this preform 401, in blow molding cavity 351, some of the molding material at opening end 403 of preform 401 fills recessed portion 323 of blow-side concave portion 322, but because excess thickened wall portion 408 is formed at opening end 403, the occurrence of sink marks on the inner surface of opening end 413 is suppressed in the molded product 411 obtained subsequently. As a result, it is possible to effectively prevent insufficient strength and quality defects at the opening end 413 of the molded product 411.

[0029] 7, in order to provide the thick-walled forming space 342 as described above, a recessed portion 337 recessed from the outer peripheral surface is formed in a portion of the outer peripheral surface of the convex portion 332 (more specifically, the protruding portion 335) of the intermediate mold 331 corresponding to the opening end 403 of the preform 401, as shown enlarged in FIG. 9. Providing the thick-walled forming space 342 by forming the recessed portion 337 on the convex portion 332 side in this manner is preferable because it prevents undercutting of the preform 401 held by the convex portion 332 on the intermediate mold 331 side when the injection molding die 311 moves from a clamped state to a mold open state in which the intermediate mold 331 is separated from the injection molding die 311. In this preform 401, a thick-walled portion 408 including a raised portion 409 protruding from the inner surface is formed at the opening end 403.

[0030] Although it depends on the shape of the protrusion 415 provided on the outer surface of the opening end 413 of the molded product 411, it is preferable to form the recessed portion 337 over the entire periphery of the outer circumferential surface of the convex mold portion 332. This makes it possible to effectively prevent sink marks from occurring on the inner surface of the opening end 413 of the molded product 411 over the entire periphery.

[0031] Here, a spiral recessed portion 337 that extends axially and spirals circumferentially on the outer surface of the convex portion 332 of the intermediate mold 331 is formed in correspondence with a protrusion 415, such as a spiral thread, provided on the outer surface of the open end 413 of the molded product 411. In this case, a spiral protrusion 409 is formed on the inner surface of the thick portion 408 of the open end 403 of the preform 401. The thick portion 408 including such a spiral protrusion 409 ensures that the molding material is efficiently filled into the spiral recessed portion 323 of the blow-side concave portion 322 during blow molding in the blow molding cavity 351, and functions to more effectively suppress the occurrence of sink marks on the inner surface of the open end 413 of the molded product 411. In this example, in addition to the spiral concave portion 337 described above, the outer surface of the convex portion 332 also has a tubular flange portion 416 provided on the outer surface of the opening end 413 of the molded product 411, and a corresponding annular concave portion corresponding to the annular recess portion of the blowing side concave portion 322.

[0032] 10, in the blow molding cavity 351, the formation region Rp of the recessed portion 337 on the outer peripheral surface of the protruding portion 332 and the formation region Rd of the recessed portion 323 on the inner peripheral surface of the blow-side recessed portion 322 preferably overlap at least partially in the axial direction (the left-right direction in FIG. 10). This is because the raised portion 409 formed on the outer surface of the open end 403 of the preform 401 by the recessed portion 337 of the protruding portion 332 effectively fills the recessed portion 323 of the blow-side recessed portion 322 with the molding material. More preferably, in the axial direction of the blow molding cavity 351, the recessed portion 337 is provided on the outer peripheral surface of the convex mold portion 332 over a forming area Rp equal to or larger than the forming area Rd of the recessed portion 323 of the blow-side concave mold portion 322 so as to cover the entirety of the forming area Rd. Other dimensions such as the depth of the recessed portion 337 of the convex mold portion 332 can be determined appropriately depending on the dimensions of the protrusion 415 provided on the open end 413 of the molded product 411, the recessed portion 323 of the blow-side concave mold portion 322, etc.

[0033] 7 has a spiral recessed portion 337 on the outer peripheral surface of the convex mold portion 332, but the shape of the recessed portion 337 is not limited to this. For example, in the convex mold portion 532 shown in FIG. 11(a), a ring-shaped recessed portion 537 is provided on the outer peripheral surface at a location corresponding to the inner surface of the open end of the preform, the ring-shaped recessed portion 537 being recessed over a certain area in the axial direction and extending all the way around in the circumferential direction. Such a recessed portion 537 may provide a wall thickness forming space 542. Although not shown in the figures, it is possible to provide various protrusions, not just spiral ones, on the outer surface of the opening end of the molded product, and the shape of the recess formed in the blowing-side concave mold portion can be changed accordingly.

[0034] 11(b), instead of or in addition to forming a recessed portion on the outer peripheral surface of the convex mold portion, a recessed portion 637 of any shape can be formed on the inner peripheral surface of the injection-side concave mold portion 612 of the injection molding die 611. This also makes the injection molding cavity have a thickened portion forming space 642, making it possible to form thickened portions in the preform.

[0035] The mold assembly 101 described above can be attached to the injection blow molding machine 1 or replaced as appropriate depending on the shape of the molded product to be manufactured. For this reason, the mold assembly 101 is not included in the injection blow molding machine 1 and is considered to be a separate device from the injection blow molding machine 1. A system including the injection blow molding machine 1 and the mold assembly 101 attached to the injection blow molding machine 1 is referred to as an injection molding system here.

[0036] (mold clamping device) The mold apparatus 101 as described above is attached to the mold clamping device 31 of the injection blow molding machine 1. The mold clamping device 31 has a mold holding mechanism 32 having a fixed platen 32a, a movable platen 32b, and an intermediate mold support frame 32c, an intermediate mold moving mechanism 61 that moves the intermediate mold support frame 32c relative to the fixed platen 32a, a platen moving mechanism 33 that moves the movable platen 32b relative to the fixed platen 32a, and a split mold opening / closing mechanism 62 that opens and closes a split mold 124 of the blow molding mold 121. The intermediate mold moving mechanism 61 and the split mold opening / closing mechanism 62 will be described later with reference to FIGS. 2 and 3.

[0037] The mold holding mechanism 32 includes a fixed platen 32a located between the injection unit 21 and the mold unit 101, a movable platen 32b located between the fixed platen 32a and the mold unit 101, which is movable toward and away from the fixed platen 32a, and an intermediate mold support frame 32c located between the fixed platen 32a and the movable platen 32b, which is movable toward and away from the fixed platen 32a. The mold clamping unit 31 is also provided with one or more tie bars 32d extending from the fixed platen 32a toward a rear platen 34 (described later) to connect the fixed platen 32a and the rear platen 34. In this example, the movable platen 32b and the intermediate mold support frame 32c are guided by the tie bars 32d in their movement toward and away from the fixed platen 32a, but there are also cases where they are not guided by the tie bars 32d.

[0038] Of the mold holding mechanism 32, the fixed platen 32a is fixedly attached to the base frame 2. On the other hand, the movable platen 32b and the intermediate mold support frame 32c are each placed on a guide member 32e laid on the base frame 2, and can slide independently of each other in directions toward and away from the fixed platen 32a.

[0039] When the movable platen 32b and the intermediate mold support frame 32c are positioned away from the fixed platen 32a, the blow molding mold 121 and the intermediate mold 131 of the mold device 101 are in a mold open state where they are open from the injection molding mold 111. By moving the movable platen 32b and the intermediate mold support frame 32c toward the fixed platen 32a from this separated position, the blow molding mold 121 and the intermediate mold 131 are in a mold closed state where they are closed against the injection molding mold 111, and by further moving the movable platen 32b and the intermediate mold support frame 32c toward the fixed platen 32a, the blow molding mold 121 and the intermediate mold 131 are in a mold clamped state where they are pressed against the injection molding mold 111. Here, the direction approaching the fixed platen 32a to which the injection molding mold 111 of the mold device 101 is attached is referred to as the front side, and the direction moving away from the fixed platen 32a is referred to as the rear side. In most parts of the mold clamping unit 31 except for the fixed platen 32a, in FIG. 1, the right side approaching the fixed platen 32a is the front side, and the left side away from the fixed platen 32a is the rear side.

[0040] The illustrated intermediate mold support frame 32c has a rectangular or other frame shape when viewed from the front, and is provided with a rotating shaft 41 that is rotatable and extends in the mold width direction (vertical direction in Figures 2(b) and 3(b)) perpendicular to the front-to-rear direction in a plane parallel to the horizontal plane. The rotating shaft 41 supports the intermediate mold 131. In this example, the axial direction of the rotating shaft 41 is parallel to the horizontal direction, but the axial direction of the rotating shaft is not limited to this, and it can also be parallel to the vertical direction, for example. A vertical injection blow molding machine may also be used.

[0041] Further, the intermediate mold support frame 32c is provided with an intermediate mold rotation mechanism that rotates the rotation shaft portion 41, thereby rotating the intermediate mold 131. Although not shown, this intermediate mold rotation mechanism can be a motor or the like provided on the intermediate mold support frame 32c. Note that a cylindrical member 42 is provided around the rotation shaft portion 41 between the intermediate mold 131 and the intermediate mold support frame 32c.

[0042] 2 and 3, the intermediate mold moving mechanism 61 that moves the intermediate mold support frame 32c relative to the fixed platen 32a can be configured with hydraulic cylinders 61a and piston rods 61b, etc., attached to the fixed platen 32a and the intermediate mold support frame 32c, respectively, and operated by a hydraulic pump driven by a motor. In this example, two pairs of hydraulic cylinders and piston rods are provided, located outside the injection molding mold 111 and the intermediate mold 131 in the mold width direction, but one pair or three or more pairs may be provided. Although not shown, the intermediate mold moving mechanism may also be configured so that the hydraulic cylinders, etc. are attached to a movable platen instead of the fixed platen, to move the intermediate mold support frame forward and backward relative to the movable platen.

[0043] As shown in FIG. 1, the platen movement mechanism 33 of the mold clamping unit 31 includes a rear platen 34 arranged on the base frame 2, a mold clamping motor 35 provided on the rear platen 34, a motion conversion mechanism 36 that converts the rotational motion of the mold clamping motor 35 into linear motion in the displacement direction of the movable platen 32b, and a toggle mechanism 37 that amplifies the force transmitted to the motion conversion mechanism 36 and transmits it to the movable platen 32b.

[0044] Of these, the motion conversion mechanism 36 can be various mechanisms capable of converting rotational motion into linear motion. In this example, the motion conversion mechanism 36 includes a screw shaft 36a that is rotationally driven by the mold clamping motor 35 and a nut 36b that is threaded onto the screw shaft 36a. The motion conversion mechanism 36 can also be a ball screw. The toggle mechanism 37, which increases the transmission force from the motion conversion mechanism 36, is formed by connecting a plurality of links 37a to 37c that connect the nut 36b of the motion conversion mechanism 36 to the movable platen 32b, and these links 37a to 37c are swingably connected by joints. The number and shapes of the links and joints can be changed as appropriate, but as shown in FIG. 1, a pair of link groups consisting of the links 37a to 37c located above and below the crosshead 37d are swingably connected to the crosshead 37d that is connected to the nut 36b and extends in the vertical direction.

[0045] In addition to the above-described mold clamping motor 35, a mold thickness adjustment motor 38 can also be provided on the rear platen 34. This mold thickness adjustment motor 38 functions to adjust the distance between the fixed platen 32a and the rear platen 34, which is movably mounted on the base frame 2, by applying a rotational driving force to a screw shaft and a nut connected to the extension portion of each tie bar 32d of the above-described mold holding mechanism 32. This makes it possible to adjust the mold thickness so that a desired mold clamping force can be applied to the mold device 101, even when replacing the mold device 101 or when the thickness of the mold device 101 is changed due to temperature changes. Although not shown in the drawings, mold thickness adjustment can also be achieved even if the fixed platen side is made movable on the base frame 2 and the rear platen side is fixed.

[0046] 2 and 3, the mold clamping unit 31 is equipped with a split mold opening / closing mechanism 62 which has a piston rod 62a, a hydraulic cylinder 62b, etc., and which drives the split mold 124 of the blow molding mold 121 to move back and forth in the mold width direction to open and close it. Note that the split molds 103b of the blow molding mold 121 which are moved in the same direction in the mold width direction by the split mold opening / closing mechanism 62 can be connected to each other by split mold connecting members 63a, 63b.

[0047] The illustrated mold clamping unit 31 is a horizontal type in which the moving direction of the movable platen 32b is parallel to the horizontal direction, but it may also be a vertical type in which the moving direction is vertical.

[0048] (injection device) The injection device 21 mainly includes a cylindrical or other shaped cylinder 22 extending toward the mold device 101, a screw 23 disposed inside the cylinder 22 with its central axis parallel to the cylinder 22 and with flights spiraling around its periphery, a band-like or other shaped heater 24 disposed around the outer periphery of the cylinder 22, and a motor box 25 disposed behind the cylinder 22 and the screw 23. Although not shown, the motor box 25 contains a metering motor that rotates the screw 23 about its central axis to accumulate a predetermined amount of molding material at the tip of the cylinder 22, an injection motor that moves the screw 23 forward and backward in both directions toward and away from the mold device 101, a pressure detection sensor that detects the pressure that the screw 23 receives from the molding material, and other components.

[0049] In this case, the direction approaching the fixed platen 32a of the mold clamping unit 31 to which the injection molding die 111 of the mold apparatus 101 is attached is defined as the front side, and the direction moving away from the fixed platen 32a is defined as the rear side. Therefore, in Fig. 1, when looking at the injection unit 21 located to the right of the fixed platen 32a, the left direction approaching the fixed platen 32a is the front side, and the right direction moving away from the fixed platen 32a is the rear side.

[0050] The cylinder 22 is provided with a supply port 22a on the rear side, in front of the motor box 25, to which a hopper can be attached for feeding molding material into the cylinder 22. A nozzle 22b, whose cross-sectional area decreases on the front side, is provided at the tip of the cylinder 22 close to the mold device 101. A water-cooled cylinder 22c, such as a water-cooled cylinder, can be provided near the supply port 22a.

[0051] The heater 24, which is disposed around the cylinder 22 including the nozzle 22b, can be divided into a plurality of sections in the axial direction of the cylinder as shown in the figure, so that the inside of the cylinder 22 inside each heater section can be heated to a different temperature. Each heater section can be provided with a temperature detector.

[0052] A backflow prevention ring (not shown) may be disposed around a constricted portion formed by partially reducing the outer diameter of the tip of the screw 23. The backflow prevention ring prevents the molding material sent forward as it moves forward and backward together with the screw 23 from flowing backward. This backflow prevention ring moves back and forth relative to the screw 23 in response to the pressure it receives from molding material located forward or backward, thereby allowing only the flow of molding material from the rear to the front.

[0053] In the injection device 21 having such a configuration, the molding material introduced into the cylinder 22 from the supply port 22a is heated by the heater 24 on the outer periphery of the cylinder 22 and melted by the rotation of the screw 23 driven by the metering motor, and is sent forward inside the cylinder 22 and accumulated at the tip of the cylinder 22. At this time, the screw 23 is displaced backward by the injection motor, forming a space at the tip of the cylinder 22 where the molding material can be accumulated.

[0054] Thereafter, by displacing the screw 23 forward, the molding material at the tip of the cylinder 22 is injected through the nozzle 22b toward the mold device 101. Further thereafter, pressure is applied to the molding material filled in the cavity of the mold device 101 through the molding material remaining at the tip of the cylinder 22, thereby performing a dwelling process. At this time, it is possible to replenish the molding material that has become deficient in the injection molding cavity of the mold device 101 due to the cooling contraction of the molding material.

[0055] Although this injection blow molding machine 1 is an inline screw type, it can also be a pre-plasticization type injection molding machine in which the plasticizing cylinder and plasticizing screw are structurally and functionally separated from the injection cylinder and injection plunger.

[0056] (Mobile device) The moving device 26 is provided, for example, below the motor box 25 of the injection device 21, and is an advance / retract drive mechanism for displacing the injection device 21 forward and backward relative to the fixed platen 32a. Various mechanisms can be used as the forward / backward drive mechanism that constitutes the moving device 26, but the moving device 26 shown in the figure is configured to include a hydraulic or other hydraulic pump 27, an electric or other pump operating motor 28 that operates the hydraulic pump 27, and a double-acting hydraulic cylinder 29 that receives hydraulic fluid from the hydraulic pump 27 and causes a piston rod, the tip of which is fixed to the fixed platen 32a, to perform an extending and retracting motion.

[0057] The moving device 26 further includes a slide base 26a to which the above-mentioned hydraulic pump 27, pump actuation motor 28, and hydraulic cylinder 29 are attached, and a guide 26b that is laid on the base frame 2 and guides the linear movement of the slide base 26a. This allows the injection device 21 placed on the slide base 26a to move forward and backward.

[0058] The moving device 26 makes it possible to move the injection device 21 away from the mold device 101, or to move the injection device 21 closer to the mold device 101 and press the nozzle 22b of the cylinder 22 of the injection device 21 against the mold device 101 with a predetermined pressure, thereby performing a so-called nozzle touch.

[0059] (Operation of injection molding machine) The injection blow molding machine 1 described above operates to perform the following steps. With the mold device 101 in the mold open state shown in Figure 2, a mold closing process is performed in which the platen moving mechanism 33 moves the movable platen 32b toward the fixed platen 32a, and the intermediate mold moving mechanism 61 moves the intermediate mold support frame 32c toward the fixed platen 32a.

[0060] Next, with a predetermined amount of molding material already accumulated and placed inside injection unit 21 by measuring during the previous molding, which will be described later, a clamping process is carried out in which mold unit 101 is clamped using clamping unit 31, as shown in Fig. 3. In the clamping process, injection molding cavity 141 is defined between injection molding die 111 and intermediate die 131, and blow molding cavity 151 is defined between blow molding die 121 and intermediate die 131.

[0061] Then, as the screw 23 advances, the molding material is injected toward the injection molding cavity 141 of the mold device 101, thereby performing the injection process of filling the injection molding cavity 141 with the molding material. In the injection process, after the molding material has been filled into the injection molding cavity 141, the screw 23 is further advanced to perform a pressure hold in which the molding material inside the tip of the injection device 21 is maintained at a predetermined pressure. Thereafter, the molding material filled into the injection molding cavity 141 is cooled and solidified. In this manner, a preform 201 is molded in the injection molding cavity 141. At this time, the molding material separately charged into the injection device 21 is melted while being sent toward the tip of the injection device 21 by the rotation of the screw 23 under heating by the heater 24, and a predetermined amount of the molding material is metered and placed at the tip.

[0062] In parallel with the above-mentioned injection process, a blowing process is carried out in blow molding cavity 151. Preform 201, which has already been molded in injection molding cavity 141 before intermediate mold 131 is inverted, is placed in blow molding cavity 151. In the blowing process, a fluid such as air or other gas is supplied to preform 201, causing preform 201 to expand in blow molding cavity 151, thereby molding molded product 211.

[0063] Thereafter, the platen moving mechanism 33 and intermediate mold moving mechanism 61 of the mold clamping device 31 are operated to move the movable platen 32b and the intermediate mold support frame 32c away from the fixed platen 32a, and the mold opening process is performed to open the mold device 101.

[0064] After the mold opening step, the split mold opening / closing mechanism 62 is used to open the split mold 124 of the blow molding mold 121 and remove the molded product 211, and then the split mold opening / closing step is performed to close the split mold 124 of the blow molding mold 121. Also, here, an intermediate mold rotation step is performed in which the intermediate mold 131 is inverted by the intermediate mold rotation mechanism. As a result, the convex mold portion 132 of the core mold of the intermediate mold 131 on the side from which the molded product 211 was collected in the split mold opening and closing step faces the injection-side concave mold portion 112 of the injection molding mold 111. On the other hand, the convex mold portion 132 of the core mold of the intermediate mold 131 on the side from which the preform 201 was molded in the injection step faces the blow-side concave mold portion 122 of the blow molding mold 121 while holding the preform 201. The intermediate mold rotating step can be carried out at approximately the same time as the split mold opening and closing step, or before or after the split mold opening and closing step.

[0065] In injection molding using the injection blow molding machine 1, the mold closing process, mold clamping process, injection process, blowing process, mold opening process, split mold opening / closing process, and intermediate mold rotating process are repeatedly performed. [Explanation of symbols]

[0066] 1 Injection blow molding machine 2 base frame 21 Injection device 22 cylinders 22a Supply port 22b nozzle 22c water-cooled cylinder 23 screw 24 Heater 25 Motor box 26 Mobile Devices 26a Slide Base 26b Guide 27 Hydraulic Pump 28 Pump operating motor 29 Hydraulic Cylinder 31 Mold clamping device 32 Mold holding mechanism 32a Fixed Platen 32b Movable platen 32c Intermediate mold support frame 32d tie bar 32e Guide member 33 Platen movement mechanism 34 Rear platen 35 Mold clamping motor 36 Motion conversion mechanism 36a Screw shaft 36b Nut 37 Toggle mechanism 37a~37c Link 37d Crosshead 38 Mold thickness adjustment motor 41 Rotating shaft 42 Cylindrical member 61 Intermediate mold movement mechanism 61a Hydraulic cylinder 61b Piston rod 62 Split mold opening and closing mechanism 62a Piston rod 62b Hydraulic cylinder 63a, 63b Split connecting member 101 Mold equipment 103b split mold 111, 311, 611 Injection mold 112, 312, 612 Concave part on injection side 113, 313 type main body 114, 314 Concave partition member 114a Step Gates 115 and 315 121, 321 Blow mold 122, 322 Concave part on blowing side 123, 323 recessed part 124, 324 split type 124a Step 131, 413 Intermediate mold 131a, 331a Core 132, 332, 532 Convex part 134, 334 base 134a Step 135, 335 protrusion 136 Annular groove 337, 537, 637 concave part 141, 341 Injection molding cavity 342, 542, 642 Wall thickness forming space 151, 351 Blow molding cavity 201, 401 preforms 202, 402 cylindrical main body 203, 403 Open end 204, 404 Sealed end 204a, 404a bottom 207, 217 Overlay part 211, 411 Molded products 212, 412 Cylindrical main body 212a Torso 212b Tapered section 213, 413 Open end 214, 414 Sealed end 214a, 414a bottom 215, 415 protruding part 216, 416 flange Rd: The area where the recessed portion is formed in the concave portion on the injection side Rp Concave area formation region in the convex part

Claims

1. An injection blow molding machine which defines an injection molding cavity between an injection-side concave mold portion and a convex mold portion in a clamped state, injects molding material into the injection molding cavity to mold a container-shaped preform having an open end, defines a blow molding cavity between a blow-side concave mold portion and a convex mold portion in a clamped state, and expands the preform placed in the blow molding cavity by supplying a fluid to mold a container-shaped molded product having an open end with a protrusion formed on its outer surface, an injection blow molding machine in which the protrusion portion is formed on the outer surface of the open end by expanding the preform in the blow molding cavity by supplying the fluid;

2. 2. The injection blow molding machine according to claim 1, wherein the preform has a thickened portion at the open end, the thickened portion being formed by injecting the molding material into the injection molding cavity.

3. 3. The injection blow molding machine according to claim 2, wherein the thickened portion includes a raised portion protruding from the inner surface of the open end.

4. 4. The injection blow molding machine of claim 3, wherein said raised portion is spiral.

5. 5. The injection blow molding machine according to claim 1, wherein the protruding portion is spiral.

6. An injection molding system comprising: the injection blow molding machine according to any one of claims 1 to 5; and a mold device attached to the injection blow molding machine.

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