Blow mold unit

Abstract

To provide a manufacturing method for a resin container, in which when a container having an undercut shape is released from a blow split mold, the container can be appropriately transported after the release.SOLUTION: A manufacturing method for a resin container having an undercut shape includes the steps of: accommodating a preform in a cavity mold having an undercut part; inserting a core mold to an inner side of the preform; introducing blow air into the preform through the core mold to blow-mold the preform into a container; gripping a neck part of the container, in which the core mold is disposed on an inner side, with a conveyance chuck from an outer side and sandwiching the neck part of the container with the core mold and the conveyance chuck; and opening the cavity mold. The container in which the neck part is sandwiched between the core mold and the conveyance chuck is released from the undercut part by opening the mold.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a method and an apparatus for manufacturing a resin container. [Background technology]

[0002] Conventionally, in large-capacity resin containers for use in, for example, water servers, a convex rib is formed on the shoulder of the container to ensure the rigidity of the container (see, for example, Patent Documents 1 and 2). Also known is a method for manufacturing a resin container (bag-in-box) for a water server using a one-step (hot parison) blow molding device (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5253085 [Patent Document 2] JP 2010-126224 A [Patent Document 3] Patent No. 3354279 Summary of the Invention [Problem to be solved by the invention]

[0004] When this type of ribbed container is blow molded, the convex rib forms an undercut shape in the blow mold. Therefore, if the container is forcibly removed from the blow mold after blow molding, the container may shake sideways when released, causing contact between the container and the blow mold or the container to fall off the conveying member, which may prevent the container from being properly transported. In particular, in the case of large-capacity ribbed containers, the gap between the large container and the blow mold tends to be small when released, making the above-mentioned phenomenon more likely to occur.

[0005] In a one-step blow molding apparatus as described in Patent Document 3, the neck part of the preform or container is always supported by the neck part during molding using a neck mold fixed to a conveying mechanism (rotary disk). In a one-step blow molding apparatus, the neck part of the preform or container is strongly supported from the outside by a neck mold with high rigidity, and the degree of engagement between the neck part and the neck mold is also high. Therefore, it can be said that there is a relatively low risk of the container falling off or other problems occurring when the container is released from the blow mold. On the other hand, in a two-step blow molding apparatus (e.g., Patent No. 5503748) or a 1.5-step blow molding apparatus (e.g., Patent No. 6118529) in which a chuck member or the like is used to attach and detach the preform or container during blow molding, there is a high risk of the container falling off or other problems occurring when the container is released from the mold.

[0006] If containers are not properly removed after blow molding in the manufacturing process for ribbed containers, productivity will drop significantly due to maintenance work such as removing the containers, and the equipment and molds will be easily damaged. The above problems can be prevented by using a blow split mold with a movable insert, but this will increase the manufacturing costs of the mold. Furthermore, in order to produce containers at high speed, it is necessary to remove the containers from the blow split mold at high speed, but when manufacturing large-capacity ribbed containers, problems during removal due to falling off or the like are even more likely to occur.

[0007] Furthermore, when a resin container having a convex rib on the shoulder is manufactured using a two-step or 1.5-step blow molding device, blow molding is not performed with the entire neck of the preform supported by a neck mold as in the one-step type, but rather the preform is supported in a free state on the upper surface of the blow mold by the protruding part of its neck (support ring or annular flange). In this embodiment, when the container is released from the mold, the protruding part of the neck may rub against the upper surface of the blow mold, causing scratches on the lower surface of the protruding part. If scratches are formed on the protruding part, the appearance of the container may be poor and there is a risk of problems in transporting it to a subsequent process. [Means for solving the problem]

[0008] One aspect of the present invention is a method for manufacturing a resin container having an undercut shape, which includes the steps of: placing a preform in a cavity mold having an undercut portion, inserting a core mold into the preform, introducing blow air into the preform through the core mold to blow mold the preform into a container, gripping the neck of the container with the core mold disposed inside from the outside with a conveying chuck and sandwiching the neck of the container between the core mold and the conveying chuck, and opening the cavity mold. By opening the mold, the container with the neck sandwiched between the core mold and the conveying chuck is released from the undercut portion. Effect of the Invention

[0009] According to one aspect of the present invention, when a container having an undercut shape is released from a blow split mold, the released container can be properly carried out. [Brief description of the drawings]

[0010] [Figure 1] 1 is a plan view showing a schematic configuration of a blow molding device according to an embodiment of the present invention; [Diagram 2] FIG. 13 is a diagram showing an outline of the transportation of preforms in the injection molding section and the cooling section. [Diagram 3] FIG. 2 is a front view of the blow molded portion and the container. [Figure 4] FIG. 4 is a plan view showing the support member in a closed state. [Diagram 5] FIG. 4 is a plan view showing the support member in an open state. [Figure 6] 1A to 1C are diagrams illustrating an example of an operation of a blow molding process. [Figure 7] This is a continuation of Figure 6. [Figure 8] This is a continuation of Figure 7. [Figure 9] This is a continuation of Figure 8. [Figure 10] This is a continuation of Figure 9. [Figure 11] 1A to 1C are diagrams showing an example of a state when a blow cavity mold is opened. [Figure 12]FIG. 13 is a diagram showing a configuration example of a blow cavity type of a first modified example. [Figure 13] 13 is a diagram showing a configuration example of a blow molding section of a second modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the embodiments, in order to make the description easier to understand, structures and elements other than the main parts of the present invention will be described in a simplified or omitted manner. In addition, in the drawings, the same elements are given the same reference numerals. Note that the shapes, dimensions, etc. of each element shown in the drawings are shown only for illustrative purposes, and do not represent the actual shapes, dimensions, etc.

[0012] Fig. 1 is a plan view showing a schematic configuration of a blow molding apparatus according to the present embodiment, Fig. 2 is a diagram showing an outline of preform transportation in an injection molding section and a cooling section, and Fig. 3 is a front view of the blow molding section and a container.

[0013] As shown in FIG. 3, a resin container (hereinafter, simply referred to as a container 300) manufactured by the blow molding apparatus of this embodiment is a large-capacity (e.g., 5 to 20 liters, preferably 9 to 15 liters) container (e.g., a bag-in-box) used to store, for example, mineral water, edible oil, etc., and is manufactured by blow molding a resin preform 200 described later. The overall shape of the container 300 is a prism with rounded corners, and its cross section is approximately rectangular. The container 300 has a neck portion 301 with an open top, a shoulder portion 302 connected to the bottom of the neck portion 301, a body portion 303 connected to the bottom of the shoulder portion 302, and a bottom portion 304 that closes the bottom end of the body portion 303. The neck portion 301 is formed with a cylindrical portion 201c having approximately the same diameter and a flange (described later) that protrudes in the outer diameter direction from the cylindrical portion 201c. Incidentally, a neck portion 301 of the container 300 and a neck portion 201 of a preform 200 described later have the same shape.

[0014] In addition, a shoulder portion of container 300 is formed with a plurality of convex ribs (convex ribs protruding in the outer diameter direction of the container) 305, which protrude outward from container 300 and extend in stripes from neck portion 301 toward body portion 303. Each of convex ribs 305 is disposed radially from neck portion 301 as a center, and serves to improve the rigidity of container 300 by increasing the radial strength of shoulder portion 302.

[0015] Furthermore, the material of the container 300 and the preform 200 is a thermoplastic synthetic resin, and can be appropriately selected depending on the application of the container 300. Specific types of materials include, for example, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (polycyclohexane dimethylene terephthalate), Tritan (Tritan (registered trademark): a copolyester manufactured by Eastman Chemical Co.), PP (polypropylene), PE (polyethylene), PC (polycarbonate), PES (polyethersulfone), PPSU (polyphenylsulfone), PS (polystyrene), COP / COC (cyclic olefin polymer), PMMA (polymethyl methacrylate: acrylic), PLA (polylactic acid), and the like.

[0016] Meanwhile, the blow molding apparatus 100 of this embodiment executes a blow molding method called the 1.5 stage method, which combines the advantages of the hot parison method and the cold parison method, in order to manufacture the above-mentioned container 300. In the 1.5 stage blow molding method, a container is manufactured by blow molding a preform 200 having heat retained during injection molding, basically similar to the hot parison method (one stage method). However, the blow molding cycle in the 1.5 stage method is set shorter than the injection molding cycle of the preform 200. Then, the multiple preforms 200 molded in one injection molding cycle are blow molded in multiple blow molding cycles (for example, three times).

[0017] As shown in FIG. 1, the blow molding apparatus 100 includes an injection molding section 110, a cooling section 120, a heating section 130, and a blow molding section 140. The blow molding apparatus 100 also includes a continuous conveying section 150 that conveys the preforms 200 discharged from the cooling section 120 to the blow molding section 140 via the heating section 130. The continuous conveying section 150 continuously and repeatedly conveys a conveying jig 152 that holds the preforms 200 along a loop-shaped conveying line 151 having a plurality of curved sections.

[0018] The injection molding section 110 performs injection molding to produce a preform 200, which is a resin molded product. 2, the injection molding section 110 includes a core mold 111 disposed above, a cavity mold 112 disposed below, and a mold clamping mechanism 114 that clamps the core mold 111 and the cavity mold 112 with tie bars 113. The injection molding section 110 injection-moldes the preform 200 by filling an injection space formed by the core mold 111 and the cavity mold 112 with a resin material (raw material) from an injection device (not shown).

[0019] Here, as shown in FIG. 6 and the like, the overall shape of the preform 200 is a bottomed cylindrical shape with one end side open and the other end side closed. The preform 200 has a neck portion 201 formed on one end side with an opening, a body portion 202 connected to the neck portion 201 and formed in a cylindrical shape, and a bottom portion 203 connected to the body portion 202 and closing the other end side. In addition, two annular flanges 201a and 201b are formed on the outer circumferential surface near the neck portion 201 of the preform 200. The two flanges 201a and 201b are formed in parallel with an interval in the axial direction below the neck portion 201. In the following description, the upper flange of the preform is also referred to as the first flange 201a, and the lower (or lowest end) flange is also referred to as the second flange 201b.

[0020] The injection molding section 110 of this embodiment is configured to simultaneously mold, for example, 3 rows × 4 pieces or 3 rows × 3 pieces of preforms 200. Furthermore, the preforms 200 are molded in an upright state with the necks 201 facing upward in the injection molding section 110, and the preforms 200 are transported in the upright state in the injection molding section 110.

[0021] As shown in FIG. 2, the injection molding section 110 further includes a receiving section 115 for removing the injection-molded preform 200 from the injection molding section 110 . The receiving section 115 is configured to be movable in the horizontal direction (X direction in the figure) to a transfer position outside the receiving position (space surrounded by the tie bars 113) below the core mold 111.

[0022] The receiving section 115 holds 12 cooling pots 119, each of which accommodates 3 rows × 4 pieces (or 3 rows × 3 pieces) of preforms 200 molded in the injection molding section 110. The cooling pots 119 of the receiving section 115 cool the accommodated preforms 200 by coming into contact with the preforms 200. The receiving section 115 also converts the spacing between the rows of the preforms 200 (spacing in the X direction in the figure) from a wide pitch state at the receiving position to a narrow pitch state at the delivery position.

[0023] The preforms 200 injection molded in the injection molding section 110 are supplied from the injection molding section 110 to the cooling section 120. The cooling section 120 forcefully cools the preforms 200 molded in the injection molding section 110. The preforms 200 are discharged from the cooling section 120 in a state where they have been cooled to a predetermined temperature, and are continuously transported along the transport line 151.

[0024] 2, a transport device 180 is provided between the injection molding section 110 and the cooling section 120, which transports the preform 200 in an upright state from the receiving section 115 to the cooling section 120. The transport device 180 includes a holding section 181 that holds the neck section 201 of the preform 200 in an upright state, and is configured to be able to move the holding section 181 in the vertical direction (Z direction in the figure) and the horizontal direction (X direction in the figure) by an air cylinder (not shown).

[0025] The cooling section 120 is configured to be invertible about a rotation axis extending in the X direction in the figure, and to be movable up and down in the Z direction (up and down direction) in the figure. Cooling pots accommodating 3 rows x 4 pieces of preforms 200 are arranged on a first surface 120a shown on the upper side of the figure of the cooling section 120, and a second surface 120b opposite to the first surface 120a.

[0026] The cooling pots arranged on the first surface 120a and the second surface 120b of the cooling section 120 are cooled by a refrigerant circulating through a refrigerant passage (not shown), and suck in and hold the accommodated preforms 200.

[0027] The cooling section 120 inverts the upright preforms 200 received from the transport device 180 to an inverted state with the necks 201 facing downward during the cooling time. The inverted preforms 200 are then delivered to transport jigs 152 of the continuous transport section 150 arranged in a plurality of rows below the cooling section 120. The transport jigs 152 holding the preforms 200 are transported sequentially along the transport line 151 by the drive of a sprocket 154 or the like.

[0028] The heating section 130 has a plurality of heaters (not shown) arranged along the conveying line 151, and heats the inverted preforms 200 continuously conveyed by the continuous conveying section 150 to a temperature suitable for stretching. In the heating section 130, the inverted preforms 200 are heated while rotating around their axial direction, so that the entire preforms 200 are heated uniformly. The heating section 130 is configured to be able to simultaneously heat at least one injection molding batch of preforms 200 (e.g., 3×4 pieces or 3×3 pieces).

[0029] The blow molding apparatus 100 further includes an intermittent conveying section 160 and a delivery section 170 downstream of the heating section 130 on the conveying line 151 . The intermittent conveying section 160 holds a plurality of preforms 200 heated by the heating section 130 and conveys them intermittently to the blow molding section 140. The delivery section 170 delivers the preforms 200 continuously conveyed by the continuous conveying section 150 from the conveying line 151 to the intermittent conveying section 160.

[0030] In this embodiment, a plurality of conveying jigs 152 continuous in the conveying direction are connected by a connecting member (not shown). The continuous conveying section 150 supplies a plurality of preforms 200 to the delivery section 170 at one time by repeatedly driving and stopping the sprocket 154a on the conveying line 151 downstream of the curved conveying section 155 that curves at a predetermined radius.

[0031] The delivery section 170 includes an inverting device (not shown) at the delivery position P0. The preforms 200 transported in an inverted state along the transport line 151 are inverted by the inverting device arranged above the preforms 200 at the delivery position P0 to an upright state. The delivery section 170 also includes, for example, an elevator (not shown) that raises and lowers the inverting device, and delivers the upright preforms 200 to the intermittent transport section 160 in a state where they are raised to a predetermined position (delivery position P1).

[0032] The intermittent conveying section 160 grips the neck portion 201 of each preform 200 in an upright state with an openable and closable conveying chuck 161 (not shown in FIG. 1). The conveying chuck 161 of the intermittent conveying section 160 grips the neck portion 201 of the preform 200 at a delivery position P1 located above the delivery position P0, and moves the preform 200 from the delivery position P1 to the blow molding position P2. In this way, the multiple preforms 200 are conveyed to the blow molding section 140 at predetermined intervals.

[0033] The blow molding section 140 has its temperature adjusted by the heating section 130, and performs stretch blow molding on a predetermined number of preforms 200 received from the delivery section 170 to manufacture containers 300. The blow molding section 140 includes a blow mold unit 140a. The blow mold unit 140a includes at least a blow cavity mold 141 (cavity mold) consisting of a pair of blow cavity split molds 1411 and 1412, a bottom mold 142, and a pair of blow mold fixing plates 149 (1491 and 1492) connected to a mold opening and closing mechanism 144 described later. The blow mold unit 140a further includes a blow core mold 143 that is an air introduction member. Since a plurality of (e.g., three or four) blow cavity split molds 1411 (1412) are fixed to one blow mold fixing plate 1491 (1492), a plurality of (e.g., three or four) blow cavity molds 141 are provided on the pair of blow mold fixing plates 149.

[0034] The bottom mold 142 is composed of bottom cavity molds 1421, the number of which is the same as the number of blow cavity molds 141 (for example, three or four), and a bottom mold fixing plate 1422 for fixing them. The blow cavity molds 141 and the bottom molds 142 are arranged in a row between a pair of blow mold fixing plates 149. Each mold part constituting the blow mold unit 140a can be simultaneously carried in or out of the blow molding apparatus 100, and can be replaced at the same time. In addition, the blow molding section 140 includes an opening / closing mechanism 144 for opening and closing the blow cavity mold 141, a first lifting device (not shown) for raising and lowering the bottom mold 142, and a second lifting device (not shown) for raising and lowering the blow core mold 143.

[0035] The blow cavity mold 141 is a metal mold that defines the shape of the container 300 excluding the bottom 304. The blow cavity mold 141 is divided at a parting surface along the depth direction (Z direction) of the paper surface of Fig. 1, and is configured to be openable and closable in the vertical direction (Y direction) of Fig. 1 via a blow mold fixing plate 149 by driving an opening / closing mechanism 144.

[0036] A cylindrical opening 141a is formed in the upper portion (or upper surface) of the blow cavity mold 141 (or the blow cavity split molds 1411, 1412). The opening 141a communicates with the inside of the mold and has a shape corresponding to the outer diameter of the neck portion 201 of the preform 200 (or larger than the minimum diameter of the neck portion 201 of the preform 200).

[0037] Further, an annular receiving groove (groove portion) 141b for receiving the second flange 201b of the preform 200 is formed on the inner peripheral surface of the opening 141a. The groove width (or the groove length in the Z direction) of the receiving groove 141b is formed to be larger than the width of the second flange 201b so as to allow the position of the second flange 201b to move downward. Furthermore, a recess 141d for accommodating a lower portion of the neck portion 201 located below the first flange 201a of the preform 200 is formed in the vertical direction (anti-Z direction) on the inner peripheral surface of the opening 141a.

[0038] Therefore, by arranging the preform 200 in accordance with the opening 141a of the blow cavity mold 141, the body 202 and bottom 203 of the preform 200 can be arranged inside the blow cavity mold 141 with the neck 201 and first flange 201a of the preform 200 protruding outside the blow cavity mold 141, as shown in Fig. 6 etc. In addition, an undercut portion 141c corresponding to the protruding rib 305 is formed on the mold surface corresponding to the container shoulder of the blow cavity mold 141 (or the blow cavity split molds 1411, 1412).

[0039] A pair of flat support members 145 are provided on the upper surface of the blow cavity mold 141. One support member 145 is provided for each blow cavity mold 141 (blow cavity split molds 1411, 1412), and has a neck support portion 145a cut out in a semicircular shape corresponding to the outer diameter of the neck of the preform 200. The pair of support members 145 are arranged such that the neck support portions 145a face each other and face inward.

[0040] The support member 145 slides in the Y direction along the upper surface of the blow cavity mold 141 by a linear motion mechanism 146 provided on the blow cavity mold 141 or the blow mold fixing plate 149, and can be opened and closed independently of the opening and closing operation of the blow cavity mold 141. Fig. 4 is a plan view showing the support member 145 in the closed position, and Fig. 5 is a plan view showing the support member 145 in the open position.

[0041] 4, when the support members 145 are in the closed position, the support members 145 approach each other toward the parting surface. As a result, the neck support portion 145a in the closed position is positioned so as to substantially overlap the opening 141a of the blow cavity mold 141 in a plan view, and the neck support portion 145a of the support member 145 can support the preform 200 by sandwiching it from both sides. The upper surface side of the neck support portion 145a of the support member 145 contacts the lower surface of the first flange 201a, and supports the preform 200 on the lower side of the first flange 201a.

[0042] 5, when the support members 145 are in the open position, they slide away from each other from the closed position. As a result, the neck support parts 145a in the open position are all retracted from the opening 141a of the blow cavity mold 141, and the support of the preform 200 by the support members 145 is released.

[0043] The bottom mold 142 is disposed below the blow cavity mold 141, and is a metal mold that defines the shape of the bottom 304 of the container 300 (more specifically, the shape of the bottom 304 is defined by the bottom cavity mold 1421). When the bottom mold 142 and the blow cavity mold 141 are closed, a mold space that defines the shape of the container 300 is formed.

[0044] The blow core mold 143 is a metal mold inserted into the neck portion 201 of the preform 200 in order to introduce compressed air (blow air) into the preform to shape the container 300. The blow core mold 143 is configured to be movable forward and backward along the axial direction of the preform 200, and has a structure in which a cylindrical outer core 143a and a cylindrical inner core 143b are concentrically arranged.

[0045] The outer core 143a is disposed on the outer periphery of the neck portion 201 of the preform 200, and covers the neck portion 201 of the preform 200 from the outer periphery during blow molding, as shown in Figs. 8 and 9 described later. As a result, the outer core 143a comes into contact with the upper surface of the first flange 201a and the upper surface of the support member 145, ensuring airtightness between the preform 200 and the blow core mold 143.

[0046] The inner core 143b is inserted into the preform 200 and comes close to the inner peripheral surface of the neck portion 201. In the blow core mold 143, the inner core 143b protrudes axially downward further than the outer core 143a. The inner core 143b supports the neck portion 201 of the preform 200 (or the neck portion 301 of the container 300) from the inner peripheral side, and serves to prevent the neck portions 201, 301 from tilting or shifting in position.

[0047] 8 and 9, during blow molding, the inner core 143b and the stretch rod 148 are inserted into the preform 200. The inner core 143b is a hollow cylindrical body, inside which the stretch rod 148 is disposed, and a flow path is formed for introducing compressed air from, for example, a compressor (not shown) into the preform 200 and discharging the compressed air from the container after blow molding.

[0048] The stretch rod 148 is configured to be movable up and down in the drawing relative to the blow core mold 143. In addition, a contact portion 148a is provided at the tip of the stretch rod 148 to come into contact with the inner bottom surface of the preform 200 to prevent misalignment during stretching.

[0049] An example of the operation of the blow molding process in the blow molding section 140 will be described below with reference to FIGS. First, while the blow core mold 143 is waiting at the upper end position, the preform 200 is transported to the position of the opening 141a of the blow cavity mold 141 in the mold open state by the transport chuck 161 of the intermittent transport unit 160. After that, the blow cavity mold 141 moves in the Y direction by driving the opening / closing mechanism 144, and changes from the mold open state to the mold closed state. Also, each support member 145 is in a closed position beforehand. When the blow cavity mold 141 changes from the mold open state to the mold closed state, the neck support portion 145a of the support member 145 is positioned below the preform 200 as the blow cavity mold 141 moves.

[0050] 6, the neck portion 201 of the preform 200 is held by the transport chuck 161, while the body portion 202 and the bottom portion 203 of the preform 200 are housed in the blow cavity mold 141. The support member 145 prevents the preform 200 from falling into the blow cavity mold 141. At the stage shown in FIG. 6, the blow core mold 143 is retracted above the preform 200, and the bottom mold 142 is retracted below the blow cavity mold 141.

[0051] Next, as shown in Fig. 7, the blow core mold 143 descends to an intermediate position, and the inner core 143b is inserted into the preform 200 up to the position of the conveying chuck 161 while the conveying chuck 161 holds the neck portion 201 of the preform 200. After that, when the conveying chuck 161 retreats, the blow core mold 143 descends further to the lower end position, and the tip of the outer core 143a comes into contact with the upper surface of the first flange 201a and / or the upper surface of the support member 145 (see Fig. 8). When the conveying chuck 161 retreats, the preform 200 descends and is placed on the upper surface of the support member 145, but since it is held from the inside by the inner core 143b, it is possible to prevent the preform 200 from taking an incorrect posture (for example, a tilted posture).

[0052] 8, the stretch rod 148 is inserted into the preform 200. Thereafter, the stretch rod 148 is lowered and its tip (contact portion 148a) is pressed against the bottom portion 203 of the preform 200, and the preform 200 is stretched along its longitudinal axis.

[0053] Then, the preform 200 is horizontally stretched by supplying blow air from the inner core 143b. As a result, as shown in Fig. 9, the preform 200 is bulged and shaped so as to be in close contact with the mold surface of the blow cavity mold 141, and is blow molded into a container 300. Note that the bottom mold 142 is controlled so that it waits at a lower position where it does not come into contact with the bottom 203 of the preform 200 before the mold is closed, and quickly rises to the molding position after the mold is closed before the start of blow molding.

[0054] 10, the stretch rod 148 retreats upward, and the blow core die 143 rises to an intermediate position. As a result, the outer periphery of the neck 301 of the container 300 is exposed to the outside, and the inner core 143b is inserted halfway inside the neck of the container 300. After that, the conveying chuck 161 grips again the outer periphery of the part of the neck 301 of the container 300 where the inner core 143b is inserted.

[0055] Here, the transport chuck 161 grips the neck 301 so that the container 300 can move downward by an amount of movement that will be described later. The transport chuck 161 also has a retaining portion 161a at its lower end that protrudes inward from the lower end. The retaining portion 161a interferes with a protrusion (e.g., a screw) of the neck 301, thereby preventing the container 300 from falling off downward.

[0056] Furthermore, since the inner core 143b is inserted into the neck 301 of the container 300, the inner circumference of the neck of the container 300 can come into contact with the outer circumference surface of the inner core 143b, and movement in the horizontal direction (XY direction) is restricted. Furthermore, the outer circumference of the neck of the container 300 is gripped from the outside by the transport chuck 161. Therefore, the neck 301 of the container 300 is sandwiched between the inner core 143b on the inner circumference side and the transport chuck 161 on the outer circumference side. This makes the neck 301 of the container 300 less likely to be displaced by a force from a planar direction (XY direction) perpendicular to the axial direction of the container 300 (i.e., the neck 301 is less likely to tilt).

[0057] 11, each support member 145 of the blow cavity mold 141 slides from the closed position to the open position. This releases the support of the container 300 by the support members 145. In addition, a gap (movement allowance) corresponding to the thickness of the retreated support member 145 is formed between the underside of the first flange 201a and the blow cavity mold 141.

[0058] Here, the conveying chuck 161 allows the container 300 to move downward, and the receiving groove 141b of the blow cavity mold 141 also allows the position of the second flange 201b to move downward. Therefore, the container 300 held by the conveying chuck 161 can move downward by the amount of the movement allowance. In addition, the blow molded container 300 shrinks after shaping due to exhaust and temperature drop, and a certain amount of gap is generated on the bottom side of the container 300. Therefore, even if the container 300 moves downward by the amount of the movement allowance, there is no interference with the container 300 on the bottom side of the blow cavity mold 141.

[0059] As described above, when the support member 145 slides to the open position, the container 300 can move down by the amount of the movement allowance. Then, when the container 300 moves down, the convex rib 305 of the container 300 is pulled away from the undercut portion 141c.

[0060] On the other hand, the transport chuck 161 allows the container 300 to descend, but has a retaining portion 161a that prevents the container 300 from falling off. When the container 300 descends before the mold is opened, the first flange 201a comes into contact with the upper surface of the blow cavity mold 141, and the second flange 201b comes into contact with the receiving groove 141b, so that the container 300 does not descend any further. Therefore, the container 300 is prevented from falling off downward by the retaining portion 161a, the first flange 201a, and the second flange 201b.

[0061] After each support member 145 slides to the open position, the blow cavity mold 141 is moved in the Y direction by driving the opening / closing mechanism 144, as shown by the arrow OP in FIG. 11, to open the mold.

[0062] The mold surface of the blow cavity mold 141 has an undercut portion 141c corresponding to the convex rib 305, and the convex rib 305 of the container 300 enters the undercut portion 141c when the mold is closed. When the blow cavity mold 141 is opened in this state, the convex rib 305 is forcibly pulled out from the undercut portion 141c. However, as described above, the neck portion 301 of the container 300 is supported by being sandwiched between the inner core 143b on the inner circumference side and the conveying chuck 161 on the outer circumference side, and the movement in the XY direction is restricted. Therefore, when the convex rib 305 is released by opening the mold, the neck portion 301 of the container 300 supported by the inner core 143b and the conveying chuck 161 provides a large resistance to the force in the mold opening direction and receives a reaction force, so that the container 300 can be peeled off and released from the blow cavity mold 141. Therefore, the event that the container 300 cannot be carried out without being released from the blow cavity mold 141 is suppressed.

[0063] Furthermore, as the support member 145 slides to the open position, the container 300 descends by the amount of the movement allowance, and as described above, the convex rib 305 of the container 300 separates from the mold surface of the undercut portion 141c. This prevents the convex rib 305 from being forcibly removed, making it easier to release the container 300 from the blow cavity mold 141.

[0064] In addition, when the support member 145 is in the open position, the container 300 may not have been lowered sufficiently. However, when the mold is opened, the convex rib 305 hits the mold surface of the blow cavity mold 141, and vertical and horizontal vibrations are applied to the container 300. As a result, the container 300 is lowered by the amount of movement due to the above vibration, and the convex rib 305 of the container 300 is separated from the mold surface of the undercut portion 141c. Therefore, even in this case, it is possible to prevent the convex rib 305 from being forcibly removed.

[0065] Furthermore, although the transport chuck 161 allows the container 300 to move downward due to vibration, the container 300 has the retaining portion 161a, so that the container 300 is prevented from falling downward due to vibration and becoming unable to be transported.

[0066] In addition, since the neck 301 of the container 300 is sandwiched between the inner core 143b and the transport chuck 161, the container 300 released from the blow cavity mold 141 is unlikely to wobble in a planar direction (XY direction) perpendicular to the axial direction. This also prevents the container 300 from coming into contact with the blow cavity mold 141 after the mold is opened and falling off.

[0067] Thereafter, the blow core mold 143 retreats upward, and the inner core 143b is pulled out from the neck portion 301 of the container 300. The container 300 is then transported by the transport chuck 161 to the removal position P3 outside the blow molding section 140 and removed. This completes the description of the blow molding process in the blow molding section 140.

[0068] As described above, in the blow molding section 140 of the blow molding apparatus 100 of this embodiment, a container 300 having an undercut-shaped convex rib 305 is manufactured. In the blow molding section 140, the preform 200 is accommodated in the blow cavity mold 141 having the undercut portion 141c, and the blow core mold 143 is inserted inside the preform 200. Then, blow air is introduced into the preform 200 through the blow core mold 143, and the preform 200 is blow molded into the container 300. After that, the neck portion 301 of the container 300 with the blow core mold 143 arranged inside is gripped from the outside by the conveying chuck 161, and the neck portion 301 of the container 300 is sandwiched between the blow core mold 143 and the conveying chuck 161. When the blow cavity mold 141 is opened, the container 300 with the neck portion 301 sandwiched between the blow core mold 143 and the transport chuck 161 is released from the undercut portion 141c.

[0069] In the blow molding section 140, the neck portion 301 is sandwiched between the blow core mold 143 and the conveying chuck 161 to release the container 300, so that the container 300 having the undercut-shaped convex rib 305 can be easily released from the blow cavity mold 141. In addition, the container 300 having the neck portion 301 sandwiched between the blow core mold 143 and the conveying chuck 161 is less likely to shake and therefore less likely to fall off the conveying chuck 161. Therefore, according to the configuration of this embodiment, the container 300 can be properly carried out from the blow molding section 140. In addition, according to the configuration of this embodiment, it is not necessary to use a split mold having a movable nest, so that the manufacturing cost of the mold can be reduced.

[0070] Furthermore, since the container 300 is released from the blow cavity mold 141 without being forcibly pulled out, friction between the lower surface of the second flange 201b of the neck 301 and the receiving groove portion 141b of the blow mold 143 (or the lower surface of the first flange 201a and the upper surface of the blow mold 143) can be reduced or eliminated. Therefore, even in a 1.5-step or 2-step blow molding device that blow-moldes a container while holding a part of the neck 301 of the preform 200 in the blow cavity mold 141, the occurrence of scratches on the protrusions of the neck 301 (support ring, annular flange, etc.) can be prevented.

[0071] The present invention is not limited to the above-described embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.

[0072] For example, in the above embodiment, a configuration example of the blow molding section in a 1.5 step type blow molding apparatus has been described as an example. However, the configuration of the blow molding section in this embodiment may be applied to a cold parison type (2 step type) blow molding apparatus that performs blow molding using a preform that has been injection molded in a separate apparatus and cooled to room temperature.

[0073] Furthermore, the shape of the container to which the present invention can be applied is not limited to that of the embodiment, and the present invention can be widely applied to cases where a container having an undercut shape is manufactured by stretch blow molding.

[0074] (First Modification) 12 is a diagram showing a configuration example of a blow molding section 140 of a first modified example. In the following explanation, elements common to the blow molding section 140 of the embodiment are given the same reference numerals, and duplicate explanations will be omitted. Note that the first modified example has the same configuration as the embodiment, except for the blow cavity mold 141 (or blow cavity split molds 1411, 1412) and the presence or absence of a movement allowance.

[0075] Unlike the embodiment, when the container 300 having the protruding rib 305 is forcibly removed from the blow cavity mold 141, the second flange 201b on the lower side of the neck 301 interferes with the receiving groove (groove portion) 141b of the blow cavity mold 141. In addition, the first flange 201a on the lower side of the neck 301 also interferes with the upper surface of the blow cavity mold 141. More specifically, when the container 300 is forcibly removed, the entire container 300 is pressed downward by the undercut portion 141c of the cavity mold 141 while being opened, so that the lower surface of the second flange 201b strongly contacts the corner portion of the receiving groove 141b of the cavity mold 141 (specifically, the first corner portion formed between the lower end surface of the receiving groove portion 141b and the recess 141d when the blow cavity split molds 1411 and 1412 are viewed from the parting surface side). This may cause the lower surface of the second flange 201b to be rubbed, resulting in uneven scratches on the lower surface of the second flange 201b.

[0076] Similarly, in the case of forced extraction, the lower surface of the first flange 201a strongly contacts the corner of the upper surface of the cavity mold 141 (specifically, the second corner formed between the upper end surface of the blow cavity split molds 1411, 1412 and the recess 141d when the blow cavity split molds 1411, 1412 are viewed from the parting surface side). If scratches are generated on the lower surface of the second flange 201b or the first flange 201a, friction resistance increases when the second flange 201b or the first flange 201a is supported and transported by a rail member, star wheel, or the like, and the container 300 may get stuck and get clogged during transportation. In addition, scratches also deteriorate the appearance of the container 300 itself.

[0077] In order to prevent the above-mentioned scratches on the flange of the neck portion 301, for example, as shown in Fig. 12, as a first modified example, the corners (first corner region and / or second corner region) of the parting surface of the blow cavity mold 141 that abuts against the flange of the container 300 may be cut into a curved shape. Specifically, the corners of the upper end of the blow cavity mold 141 (specifically, the blow cavity split molds 1411, 1412) through which the neck portion 301 is inserted at the parting surface of the blow cavity mold 141 and the corners of the lower side of the receiving groove 141b are cut into a curved shape (i.e., the corners are chamfered into a curved shape). The above-mentioned two corners are formed on each of the blow cavity split molds 1411, 1412.

[0078] In order to further reduce scratches on the flange of the neck portion 301, the upper edge of the opening 141a (the semicircular edge in top view formed between the lower end surface of the counterbore on which the first flange 201a fits (rests) and the recess 141d) and the lower edge of the receiving groove 141b (the semicircular edge in top view formed between the lower end surface of the receiving groove 141b and the recess 141d) may also be cut into a curved shape. However, since there is a risk of the preform 200 being displaced significantly with respect to the blow cavity mold 141, it is preferable to set the chamfering dimension of the corners larger than the chamfering dimension of the edges. The above-mentioned edges are formed on each of the blow cavity split molds 1411 and 1412.

[0079] For example, the corners of the portions shown by the broken lines in Fig. 12 are cut (cut and chamfered) to form a flat portion of an equilateral triangle with a side of 0.7 mm to 0.9 mm, and the cut portion (flat portion) is polished so as to approximate a hemisphere, and finally the corners are chamfered to form a curved surface of a hemisphere. The edges may also be cut (cut and chamfered) by, for example, 0.1 mm to 0.2 mm, and then the cut portion is polished so as to approximate a fan shape (quadrant shape), and chamfered to form a curved surface of a fan shape. In addition, in the blow cavity mold 141 (specifically, the blow cavity split molds 1411 and 1412), the corners of the receiving groove portion 141b and the opening portion 141a may be chamfered to form a curved surface, and the radius of the roundness of the processed corners (radius of curvature, R or SR) may be set to 0.8 mm to 1.5 mm (preferably 1.0 mm to 1.2 mm). The edges of receiving groove 141b and opening 141a may also be chamfered to set the radius (radius of curvature, R) of the edges after processing to 0.3 mm to 0.8 mm (preferably 0.4 mm to 0.6 mm).

[0080] According to the configuration of the first modified example, as in the embodiment, even if forceful removal is performed, the underside of the flange of the neck portion 301 is less likely to be scraped by the corners of the blow cavity mold 141, so that scratches are less likely to occur on the underside of the flange.

[0081] (Second Modification) As another method for preventing damage to the flange of neck portion 301, support member 145 may be configured to receive the flange of neck portion 301 when the mold is closed, and support member 145 may be moved away from around neck portion 301 before blow cavity mold 141 is opened.

[0082] 13 is a diagram showing a configuration example of a blow molding section 140 of the second modified example. In the following explanation, elements common to the blow molding section 140 of the embodiment are given the same reference numerals, and duplicate explanations will be omitted. Note that the second modified example has the same configuration as the embodiment, except for the blow cavity mold 141 (or blow cavity split molds 1411, 1412) and the presence or absence of a movement allowance.

[0083] In the blow molding section 140 of the second modification, the support member 145 is formed thicker in the Z direction than in the above embodiment, and is configured to be able to support a portion including the second flange 201b of the neck portion 301 (or the neck portion 201) from both sides in the container height direction (Z direction). The neck support portion 145a of the support member 145 is formed with an annular receiving groove (groove portion) 145a1 for receiving the second flange 201b of the neck portion 301.

[0084] 13 shows a state in which the pair of support members 145 are in the closed position. When the support members 145 are in the closed position, the support members 145 approach each other toward the parting surface. In this closed position, the neck portion 301 is supported by the support members 145 with the second flange 201b accommodated in the receiving groove 145a1 of the support members 145 and the first flange 201a abutting against the upper surface of the support members 145.

[0085] In the second modified example, the support member 145 is in the closed position from the time when the blow cavity mold 141 is closed, and is closed together with the blow cavity mold 141 to support the neck portion 201 of the preform 200. After that, when the blow molding of the container 300 is completed and the container 300 is gripped by the conveying chuck 161, the linear motion mechanism 146 operates to slide the support member 145 in the Y direction (the direction of the arrow OP) to move to the open position.

[0086] As a result, the support member 145 is separated from the neck portion 301, and the second flange 201b does not interfere with the receiving groove 145a1 of the support member 145. Also, the first flange 201a does not interfere with the upper surface of the support member 145. In other words, when the support member 145 moves to the open position, a predetermined gap is formed between the first flange 201a and the second flange 201b and the upper surface of the blow cavity mold 141, and they are not in contact with each other. Note that a movement allowance that allows the container 300 to move in the axial direction (downward in the Z direction) without contacting the flange and the support member 145 may or may not be formed. When the movement allowance is formed, the transport chuck 161 grips the neck portion 301 so that the container 300 can move downward (so that the container 300 can move down a distance equivalent to the movement allowance). When the movement allowance is not formed, the transport chuck 161 grips the neck portion 301 so that the container 300 cannot move downward.

[0087] Thereafter, the blow cavity mold 141 is opened, and the convex rib 305 of the container 300 is pulled away from the undercut portion 141c. At this time, the entire container 300 is pushed downward by the undercut portion 141c of the cavity mold 141, but since the support member 145 is retracted from the neck portion 301, there is no member interfering with the lower surface of the second flange 201b. Therefore, in addition to the same effects as the above embodiment, the configuration of the second modified example can also prevent scratches caused by interference with the lower surface member of the flange when the container 300 having the convex rib 305 is opened. Also, when the transport chuck 161 supports the container 300 so that the container 300 can be moved downward, the same advantages as the embodiment can be secured.

[0088] In addition, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0089] 100...blow molding apparatus, 110...injection molding section, 120...cooling section, 130...heating section, 140...blow molding section, 141...blow cavity mold, 141b...receiving groove, 141c...undercut section, 143...blow core mold, 143a...outer core, 143b...inner core, 144...opening / closing mechanism, 145...support member, 147...inner tube, 148...stretch rod, 160...intermittent conveying section, 161...convex chuck, 200...preform, 201...neck, 201a, 201b...flanges, 300...container, 301...neck, 302...shoulder, 305...projecting rib

Claims

1. A blow mold unit used to manufacture a resin container having an annular flange on the outer peripheral surface of a neck portion and a protruding rib-like undercut-shaped portion on a shoulder portion, The blow mold unit comprises: A blow cavity mold consisting of a pair of blow cavity split molds; a pair of blow mold fixing plates to which the blow cavity split molds are respectively fixed; The mold is at least a bottom mold including a bottom cavity mold and a bottom mold fixing plate. the blow cavity split mold has an opening having a groove portion for receiving the flange and capable of accommodating the neck portion, and an undercut portion formed on a mold surface corresponding to the shoulder portion and having a shape corresponding to a protruding rib; The corners of the lower surface side of the groove portion on the parting surface of the blow cavity split mold are chamfered into a curved shape. Blow type unit.

2. The opening is formed so as to communicate from the upper surface of the blow cavity mold to the inside of the mold, and a recess is formed on the inner peripheral surface of the opening to accommodate the groove portion and the neck portion located below the flange. The blow mold unit according to claim 1 .

3. When the blow cavity split mold is viewed from the parting surface side, the corner portion is located between the lower end surface of the groove portion and the recess extending in the vertical direction. The blow mold unit according to claim 2.

4. The groove portion has a semicircular shape when viewed from above and further has an edge portion formed between the groove portion and the recess portion, and the edge portion is chamfered into a curved shape. The blow mold unit according to claim 3.

5. The flange of the neck portion has a first flange and a second flange spaced apart in the axial direction, the opening of the blow cavity split mold has a first groove portion that receives the first flange and a second groove portion that receives the second flange, a corner portion on a lower surface side of the first groove portion and a corner portion on a lower surface side of the second groove portion are each chamfered into a curved shape on a parting surface of the blow cavity split mold; The blow mold unit according to claim 3.

6. The corner portion is formed into a hemispherical curved surface. A blow mould unit according to any one of claims 1 to 5.

7. The radius of curvature of the corner is 0.8 mm to 1.5 mm. A blow mould unit according to any one of claims 1 to 5.

8. A blow mold unit used in the manufacture of a resin container having an annular flange on the outer peripheral surface of a neck portion and a protruding rib-like undercut-shaped portion on a shoulder portion, The blow mold unit comprises: A blow cavity mold consisting of a pair of blow cavity split molds; a pair of blow mold fixing plates to which the blow cavity split molds are respectively fixed; A bottom mold including a bottom cavity mold and a bottom mold fixing plate; a pair of support members each arranged on an upper surface side of the blow cavity split mold and capable of supporting the neck portion by sandwiching the neck portion in a closed position; The blow cavity split mold has an undercut portion formed on a mold surface corresponding to the shoulder portion and having a shape corresponding to the protruding rib, The pair of support members each have a neck support portion that is cut out to correspond to an outer diameter of the neck portion and has a groove portion that receives the flange, The pair of support members can move to an open position when the pair of blow cavity split dies are closed, thereby retracting the groove portion from the flange. Blow type unit.

9. The pair of blow cavity split dies and the pair of support members have the same opening and closing direction.

9. The blow mold unit according to claim 8.

10. By moving the pair of support members to the open position, a movement allowance is formed in which the container can move axially without contact between the flange and the support members when the pair of blow cavity split molds are opened. The blow mold unit according to claim 8 or 9.

Images