Blow-type 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 Blow-type unit .

Background Art

[0002] Conventionally, in a large-capacity resin container such as for a water server, a container having a convex rib formed on the shoulder thereof to ensure the rigidity of the container is known (see, for example, Patent Documents 1 and 2). Also, a method of manufacturing a resin container (back-in-box) for a water server using a one-step (hot parison type) blow molding apparatus is known (see, for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] When blow molding this type of ribbed container, the convex rib has an undercut shape with respect to the blow mold. Therefore, if the container is forcibly removed from the blow mold after blow molding, the container may sway laterally during脱模, and contact between the container and the blow mold or the container may fall off from the conveying member, etc., which may prevent proper removal of the container. In particular, in the case of a large-capacity ribbed container, the gap at the time of脱模 between the enlarged container and the blow mold tends to be small, so the above events are more likely to occur.

[0005] In a one-step blow molding apparatus like the one described in Patent Document 3, the preform and container are constantly supported during molding by a neck mold fixed to a conveying mechanism (rotating disc) via their neck portions. In a one-step blow molding apparatus, the neck portions of the preform and container are strongly supported from the outside by a highly rigid neck mold, and the degree of engagement between the neck portion and the neck mold is also high. Therefore, the risk of problems such as the container falling off during demolding from the blow mold is relatively low. 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) that performs attachment and detachment operations to the preform and container using a chuck member or the like during blow molding, the risk of problems such as the container falling off during demolding is higher.

[0006] If the containers are not properly removed after blow molding during the manufacturing process of ribbed containers, productivity will be significantly reduced during maintenance work such as container removal, and equipment and molds will be more prone to damage. While the above issues can be prevented by using a blow mold with movable inserts, this increases the manufacturing cost of the mold. Furthermore, high-speed removal of containers from the blow mold is necessary for high-speed production, but when manufacturing large-capacity ribbed containers, problems during removal, such as detachment, become even more likely.

[0007] Furthermore, when manufacturing resin containers with protruding ribs on the shoulder using a two-step or 1.5-step blow molding machine, blow molding is sometimes performed with the preform supported freely on the upper surface of the blow mold by the protruding part of its neck (support ring or annular flange), rather than with a neck mold supporting the entire neck portion as in a one-step machine. In this configuration, when the container is released from the mold, the protrusion on the neck portion may rub against the upper surface of the blow mold, potentially forming scratches on the underside of the protrusion. If scratches form on the protrusion, the appearance of the container will be poor, which may cause problems during transport to subsequent processes. [Means for solving the problem]

[0008] One aspect of the present invention is a blow mold unit applied to the manufacture of a resin container having an annular flange on the outer circumferential surface of the neck and a convex rib-shaped undercut portion on the shoulder. The blow mold unit comprises at least 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 each fixed, and a bottom mold consisting of a bottom cavity mold and a bottom mold fixing plate. The blow cavity split mold has a groove for receiving the flange and an opening capable of accommodating the neck, and an undercut portion formed on the mold surface corresponding to the shoulder, having a shape corresponding to the convex rib. The corners on the lower side of the groove on the parting surface of the blow cavity split mold are chamfered in a curved shape. Another aspect of the present invention is a blow mold unit applied to the manufacture of a resin container having an annular flange on the outer circumferential surface of the neck and a convex rib-shaped undercut portion on the shoulder. The blow mold unit comprises at least 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 each fixed, a bottom mold consisting of a bottom cavity mold and a bottom mold fixing plate, and a pair of support members respectively arranged on the upper surface side of the blow cavity split mold and capable of clamping and supporting the neck in the closed position. The blow cavity split mold is The corresponding area of ​​the neck that covers a part of the neck from the outside, Undercut portion formed on the mold surface corresponding to the shoulder area, with a shape corresponding to the convex rib. and The pair of support members each have a neck support portion that is notched to correspond to the outer diameter of the neck portion and has a groove for receiving the flange. Support the container so that it is lifted against the blow cavity splitting mold. When the pair of blow cavity split molds are closed, they can be moved to the open position, retracting the groove portion relative to the flange. [Effects of the Invention]

[0009] One aspect of the present invention Other forms According to this, when a container with an undercut shape is demolded from a blow mold, the container after demolding This can prevent scratches from occurring on the flange. [Brief explanation of the drawing]

[0010] [Figure 1] It is a plan view schematically showing the configuration of the blow molding apparatus of this embodiment. [Figure 2] It is a figure showing an outline of conveyance of preforms in an injection molding section and a cooling section. [Figure 3] It is a front view of a blow molding section and a container. [Figure 4] It is a plan view showing a support member in a closed state. [Figure 5] It is a plan view showing a support member in an open state. [[ID=​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Figure 1 is a schematic plan view showing the configuration of the blow molding apparatus of this embodiment. Figure 2 is a diagram illustrating the general flow of preforms in the injection molding section and cooling section. Figure 3 is a front view of the blow molding section and container.

[0013] As shown in Figure 3, the resin container (hereinafter simply referred to as container 300) manufactured by the blow molding apparatus of this embodiment is a large-capacity container (e.g., 5 to 20 liters, preferably 9 to 15 liters) used for storing, for example, mineral water or cooking oil (e.g., a bag-in-box), and is manufactured by blow molding a resin preform 200, which will be described later. The overall shape of container 300 is a rectangular prism with rounded corners, and its cross-section is substantially rectangular. Container 300 has a neck portion 301 that is open at the top, a shoulder portion 302 connected below the neck portion 301, a body portion 303 connected below the shoulder portion 302, and a bottom portion 304 that closes the lower end of the body portion 303. The neck portion 301 has a cylindrical portion 201c of approximately the same diameter and a flange (described later) that protrudes outward from the cylindrical portion 201c. Furthermore, the neck portion 301 of the container 300 and the neck portion 201 of the preform 200, which will be described later, are identical in shape.

[0014] Furthermore, multiple convex ribs (convex ribs that protrude in the outer diameter direction of the container) 305 are formed on the shoulder portion of the container 300, protruding outward from the container 300 and extending in a striated manner from the neck portion 301 toward the body portion 303. Each convex rib 305 is arranged radially from the neck portion 301 and serves to improve the rigidity of the container 300 by increasing the radial strength of the shoulder portion 302.

[0015] Furthermore, the materials for container 300 and preform 200 are thermoplastic synthetic resins, which can be appropriately selected depending on the application of container 300. Specific examples of materials include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (polycyclohexanedimethylene terephthalate), Tritan (Tritan®: a copolyester manufactured by Eastman Chemical Corporation), PP (polypropylene), PE (polyethylene), PC (polycarbonate), PES (polyethersulfone), PPSU (polyphenylsulfone), PS (polystyrene), COP / COC (cyclic olefin polymer), PMMA (polymethyl methacrylate: acrylic), and PLA (polylactic acid).

[0016] On the other hand, the blow molding apparatus 100 of this embodiment performs 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, the container is manufactured by blow molding a preform 200 that retains heat from injection molding, basically the same as the hot parison method (1-stage method). However, the blow molding cycle in the 1.5-stage method is set to be shorter than the injection molding cycle of the preform 200. Multiple preforms 200 molded in one injection molding cycle are then blow molded in multiple (for example, three) blow molding cycles.

[0017] As shown in Figure 1, the blow molding apparatus 100 comprises an injection molding section 110, a cooling section 120, a heating section 130, and a blow molding section 140. Furthermore, the blow molding apparatus 100 includes a continuous transport unit 150 that transports the preform 200 discharged from the cooling unit 120 to the blow molding unit 140 via the heating unit 130. The continuous transport unit 150 continuously and repeatedly transports a transport jig 152 that holds the preform 200 along a loop-shaped transport line 151 having multiple curved sections.

[0018] The injection molding unit 110 injection molds the preform 200, which is a resin molded product. As shown in Figure 2, the injection molding unit 110 includes a core mold 111 positioned above, a cavity mold 112 positioned below, and a clamping mechanism 114 that clamps the core mold 111 and cavity mold 112 together using tie bars 113. The injection molding unit 110 injection molds the preform 200 by filling the injection space formed by the core mold 111 and cavity mold 112 with resin material (raw material) from an injection device (not shown).

[0019] Here, the overall shape of the preform 200 is a bottomed cylindrical shape with one end open and the other end closed, as shown in Figure 6, etc. The preform 200 has a neck portion 201 formed at one end with an opening, a cylindrical body portion 202 connected to the neck portion 201, and a bottom portion 203 connected to the body portion 202 that closes the other end. 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 parallel to each other with an axial gap between them on the lower side of the neck portion 201. In the following description, the upper flange of the preform will also be referred to as the first flange 201a, and the lower (or bottommost) flange will also be referred to as the second flange 201b.

[0020] The injection molding unit 110 of this embodiment is configured to simultaneously mold, for example, 3 rows x 4 or 3 rows x 3 preforms 200. Furthermore, the preforms 200 are molded in an upright position with the neck portion 201 facing upward in the injection molding unit 110, and the preforms 200 are transported in an upright position in the injection molding unit 110.

[0021] Furthermore, as shown in Figure 2, the injection molding section 110 is further equipped with 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 horizontally (in the X direction in the figure) to a handover position outside the receiving position (the space enclosed by the tie bar 113) on the lower side of the core mold 111.

[0022] The receiving section 115 holds 12 cooling pots 119, each containing a 3x4 (or 3x3) preform 200 molded in the injection molding section 110. The cooling pots 119 of the receiving section 115 cool the preform 200 by contacting it. The receiving section 115 also converts the spacing between the rows of preform 200 (spacing in the X direction in the figure) from the wide-pitch state at the receiving position to the narrow-pitch state at the transfer position.

[0023] The preform 200, which is injection molded in the injection molding section 110, is supplied from the injection molding section 110 to the cooling section 120. The cooling section 120 forcibly cools the preform 200 molded in the injection molding section 110. The preform 200 is discharged from the cooling section 120 after being cooled to a predetermined temperature and is continuously conveyed along the conveyor line 151.

[0024] As shown in Figure 2, a transport device 180 is provided between the injection molding unit 110 and the cooling unit 120 to transport the preform 200 in an upright position from the receiving unit 115 to the cooling unit 120. The transport device 180 includes a holding unit 181 that holds the neck portion 201 of the upright preform 200, and is configured to be movable 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 unit 120 is reversible around a rotation axis extending in the X direction in the figure, and is configured to be able to move up and down in the Z direction (vertical direction) in the figure. Cooling pots for housing 3 rows x 4 units of preform 200 are arranged on the first surface 120a shown on the upper side of the cooling unit 120 in the figure, and on the second surface 120b facing the first surface 120a.

[0026] Cooling pots positioned on the first surface 120a and the second surface 120b of the cooling unit 120 are cooled by a refrigerant circulating through a refrigerant passage (not shown), and suck in and hold the contained preform 200.

[0027] The cooling unit 120 inverts the upright preform 200 received from the conveying device 180 into an inverted state with the neck portion 201 facing downwards during the cooling period. The inverted preform 200 is then transferred to the conveying jigs 152 of the continuous conveying unit 150, which is arranged in multiple rows below the cooling unit 120. The conveying jigs 152 holding the preform 200 are sequentially conveyed along the conveying line 151 by the drive of a sprocket 154 or the like.

[0028] The heating unit 130 has multiple heaters (not shown) arranged along the transport line 151 and heats the inverted preform 200, which is continuously transported by the continuous transport unit 150, to a temperature suitable for stretching. Inside the heating unit 130, the inverted preform 200 is heated while rotating around its axial direction, thereby uniformly heating the entire preform 200. The heating unit 130 is configured to simultaneously heat, for example, at least enough preform 200 for one injection molding batch (e.g., 3 x 4 or 3 x 3 units).

[0029] Furthermore, the blow molding apparatus 100 is equipped with an intermittent conveying section 160 and a transfer section 170 downstream of the heating section 130 in the conveying line 151. The intermittent conveying unit 160 holds multiple preforms 200 heated by the heating unit 130 and conveys them intermittently to the blow molding unit 140. The transfer unit 170 transfers the preforms 200 that have been continuously conveyed by the continuous conveying unit 150 from the conveying line 151 to the intermittent conveying unit 160.

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

[0031] The transfer unit 170 is equipped with an inversion device (not shown) at the transfer position P0. The preform 200, which has been transported in an inverted state along the transport line 151, is inverted to an upright state at the transfer position P0 by the inversion device located above the preform 200. The transfer unit 170 is also equipped with, for example, a lifting device (not shown) for raising and lowering the inversion device, and the upright preform 200 is raised to a predetermined position (transfer position P1) and then transferred to the intermittent transport unit 160.

[0032] The intermittent conveying unit 160 uses an openable and closable conveying chuck 161 (not shown in Figure 1) to grip the neck portion 201 of each upright preform 200. The conveying chuck 161 of the intermittent conveying unit 160 then grips the neck portion 201 of the preform 200 at the transfer position P1, which is located above the transfer position P0, and moves the preform 200 from the transfer position P1 to the blow molding position P2. As a result, multiple preforms 200 are conveyed to the blow molding unit 140 at predetermined intervals.

[0033] The blow molding section 140 is temperature-controlled by the heating section 130 and performs stretch blow molding on a predetermined number of preforms 200 received from the transfer 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) composed 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, 1492) connected to a mold opening / closing mechanism 144, which will be described later. The blow mold unit 140a further includes a blow core mold 143, which is an air introduction member. Since multiple (e.g., three or four) blow cavity split molds 1411 (1412) are fixed to one blow mold fixing plate 1491 (1492), multiple (e.g., three or four) blow cavity molds 141 are provided on a pair of blow mold fixing plates 149.

[0034] The bottom mold 142 consists of the same number (e.g., three or four) of bottom cavity molds 1421 as the blow cavity mold 141, and bottom mold fixing plates 1422 that secure them. The blow cavity mold 141 and the bottom mold 142 are arranged in a row between a pair of blow mold fixing plates 149. Each mold component constituting the blow mold unit 140a can be simultaneously loaded into or unloaded from the blow molding apparatus 100 and replaced at once. The blow molding section 140 also includes an opening / closing mechanism 144 for opening and closing the blow cavity mold 141, a first lifting device (not shown) for moving the bottom mold 142 up and down, and a second lifting device (not shown) for moving the blow core mold 143 up and down.

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

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

[0037] Furthermore, an annular receiving groove (groove portion) 141b is formed on the inner circumferential surface of the opening 141a to receive the second flange 201b of the preform 200. The groove width (or groove length in the Z direction) of the receiving groove 141b is formed to be larger than the width of the second flange 201b in order to allow the position of the second flange 201b to move downward. In addition, a recess 141d is formed vertically (opposite the Z direction) on the inner circumferential surface of the opening 141a to accommodate the lower portion of the neck portion 201 located below the first flange 201a of the preform 200.

[0038] Therefore, by positioning the preform 200 to match the opening 141a of the blow cavity mold 141, as shown in Figure 6, the neck portion 201 and the first flange 201a of the preform 200 can be positioned outside the blow cavity mold 141, while the body portion 202 and the bottom portion 203 of the preform 200 can be positioned inside the blow cavity mold 141. In addition, an undercut portion 141c corresponding to the convex rib 305 is formed on the mold surface of the blow cavity mold 141 (or blow cavity split mold 1411, 1412) that corresponds to the container shoulder portion.

[0039] Furthermore, 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 mold 1411, 1412), and each has a semicircular neck support portion 145a cut out to correspond to the outer diameter of the neck of the preform 200. The pair of support members 145 are arranged so that their neck support portions 145a face inward and opposite each other.

[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. Figure 4 is a plan view showing the support member 145 in the closed position, and Figure 5 is a plan view showing the support member 145 in the open position.

[0041] As shown in Figure 4, when the support members 145 are in the closed position, the support members 145 are close to each other toward the parting surface. As a result, in the closed position, the neck support portion 145a is positioned to substantially overlap with the opening 141a of the blow cavity mold 141 in a plan view, and the preform 200 can be supported by being sandwiched between the neck support portion 145a of the support members 145 from both sides. The upper surface of the neck support portion 145a of the support members 145 is in contact with the lower surface of the first flange 201a, and the preform 200 is supported below the first flange 201a.

[0042] As shown in Figure 5, when the support members 145 are in the open position, they slide apart from each other from the closed position. As a result, the neck support portions 145a in the open position are 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 positioned below the blow cavity mold 141 and is a 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 is formed that defines the shape of the container 300.

[0044] The blow core mold 143 is a mold inserted into the neck portion 201 of the preform 200 to form the container 300 by introducing compressed air (blow air) into the preform. The blow core mold 143 is configured to move back and forth 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 arranged concentrically.

[0045] The outer core 143a is positioned on the outer circumference of the neck portion 201 of the preform 200, and as shown in Figures 8 and 9 described later, it covers the neck portion 201 of the preform 200 from the outer circumference during blow molding. 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 is in close proximity to the inner circumferential surface of the neck portion 201. In the blow-core type 143, the inner core 143b protrudes axially downward more 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 circumferential side and plays a role in preventing tilting and misalignment of the neck portions 201 and 301.

[0047] Furthermore, as shown in Figures 8 and 9 described later, during blow molding, the inner core 143b and the stretching rod 148 are inserted into the preform 200. The inner core 143b is a hollow cylindrical body, and the stretching rod 148 is positioned inside it. A passage is also formed for introducing compressed air into the preform 200 from, for example, a compressor (not shown) and for exhausting the compressed air from the container after blow molding.

[0048] The stretching rod 148 is configured to move back and forth in the vertical direction relative to the blow core mold 143 in the figure. In addition, the tip of the stretching rod 148 is provided with a contact portion 148a that contacts the inner bottom surface of the preform 200 to prevent misalignment during stretching.

[0049] The following describes an example of operation in the blow molding process in the blow molding section 140, with reference to Figures 6 to 11. First, with the blow core mold 143 waiting at its upper end position, the preform 200 is transported by the transport chuck 161 of the intermittent transport unit 160 to the position of the opening 141a of the blow cavity mold 141 in the open state. Then, the blow cavity mold 141 moves in the Y direction by the drive of the opening / closing mechanism 144, changing from the open state to the closed state. Also, each support member 145 is initially in the closed position. When the blow cavity mold 141 changes from the open state to the 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] As a result, as shown in Figure 6, the neck portion 201 of the preform 200 is held by the transport chuck 161, while the body portion 202 and bottom portion 203 of the preform 200 are housed within the blow cavity mold 141. In addition, the support member 145 prevents the preform 200 from falling into the blow cavity mold 141. At the stage shown in Figure 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 Figure 7, the blow core mold 143 descends to an intermediate position, and the inner core 143b is inserted into the preform 200 to the position of the conveyor chuck 161, while the conveyor chuck 161 still grips the neck portion 201 of the preform 200. After that, when the conveyor chuck 161 retracts, the blow core mold 143 descends further to its 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 Figure 8). When the conveyor chuck 161 retracts, the preform 200 descends and is placed on the upper surface of the support member 145, but because it is held from the inside by the inner core 143b, it is possible to prevent the preform 200 from taking an incorrect posture (e.g., an inclined posture).

[0052] Next, as shown in Figure 8, the stretching rod 148 is inserted into the preform 200. Then, the stretching rod 148 descends and its tip (contact portion 148a) is pressed against the bottom 203 of the preform 200, causing the preform 200 to be stretched along its longitudinal axis.

[0053] Then, by supplying blow air from the inner core 143b, the preform 200 is stretched along its lateral axis. As a result, as shown in Figure 9, the preform 200 expands and is shaped to closely adhere to the mold surface of the blow cavity mold 141, and is blow-molded into the container 300. The bottom mold 142 waits in a lower position that does not come into contact with the bottom 203 of the preform 200 before the mold is closed, and is controlled to quickly rise to the molding position after the mold is closed and before blow molding begins.

[0054] Next, as shown in Figure 10, the extension rod 148 retracts upward and the blow core type 143 rises to an intermediate position. As a result, the outer circumference of the neck portion 301 of the container 300 is exposed to the outside, and the inner core 143b is partially inserted into the inside of the neck portion of the container 300. Subsequently, the transport chuck 161 grips the outer circumference of the portion of the neck portion 301 of the container 300 in which the inner core 143b is inserted.

[0055] Here, the transport chuck 161 grips the neck portion 301 so that the container 300 can move downward by the amount of the movement described later. The transport chuck 161 also has a retaining portion 161a on its lower end that protrudes inward. The retaining portion 161a interferes with the projection (for example, a screw) of the neck portion 301, thereby preventing the container 300 from falling downward.

[0056] Furthermore, since the inner core 143b is inserted into the neck portion 301 of the container 300, the inner circumference of the neck portion of the container 300 can come into contact with the outer surface of the inner core 143b, restricting horizontal movement (XY direction). In addition, the outer circumference of the neck portion of the container 300 is gripped from the outside by the transport chuck 161. Therefore, the neck portion 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. As a result, the neck portion 301 of the container 300 is less susceptible to displacement by forces from the plane direction (XY direction) perpendicular to the axial direction of the container 300 (i.e., the neck portion 301 is less likely to tilt).

[0057] Subsequently, as shown in Figure 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 (move) equal to the thickness of the retracted support member 145 is formed between the lower side of the first flange 201a and the blow cavity mold 141.

[0058] Here, the transport 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 transport chuck 161 can move downward by the amount of the movement. In addition, the blow-molded container 300 shrinks after shaping due to exhaust and temperature drop, creating a certain amount of gap on the bottom side of the container 300. Therefore, even if the container 300 moves downward by the amount of the movement, there is no interference between the container 300 and 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 descend by the amount of the movement. When the container 300 descends, 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 part 161a that prevents the container 300 from falling out. Also, when the container 300 descends before the mold opens, 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, preventing the container 300 from descending any further. Therefore, the container 300 does not fall out downwards, which is prevented by the retaining part 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 moves in the Y direction and opens up due to the drive of the opening / closing mechanism 144, as shown by the arrow OP in Figure 11.

[0062] The mold surface of the blow cavity mold 141 has an undercut portion 141c corresponding to the convex rib 305, and when the mold is closed, the convex rib 305 of the container 300 is inserted into the undercut portion 141c. When the blow cavity mold 141 is opened in this state, the convex rib 305 is forcibly removed from the undercut portion 141c. However, as described above, the neck portion 301 of the container 300 is held and supported by the inner core 143b on the inner circumference side and the transport chuck 161 on the outer circumference side, and its 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, which is supported by the inner core 143b and the transport chuck 161, provides a large resistance to the force in the mold opening direction and receives a reaction force, so the container 300 can be pulled away from the blow cavity mold 141 and released. Thus, the phenomenon in which the container 300 cannot be discharged 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 moves downward by the amount of the movement, and as described above, the convex rib 305 of the container 300 separates from the mold surface of the undercut portion 141c. This eliminates the forced removal of the convex rib 305, making it easier to separate the container 300 from the blow cavity mold 141.

[0064] Furthermore, when the support member 145 is moved to the open position, the container 300 may not have descended sufficiently. However, when the mold opens, the convex rib 305 comes into contact with the mold surface of the blow cavity mold 141, causing vertical and horizontal vibrations to be applied to the container 300. As a result, the container 300 descends by the amount of movement due to the above vibrations, and the convex rib 305 of the container 300 separates from the mold surface of the undercut portion 141c. Therefore, even in this case, forced removal of the convex rib 305 can be avoided.

[0065] Furthermore, although the transport chuck 161 allows the container 300 to descend due to vibration, the presence of a retaining portion 161a prevents the container 300 from falling off downwards due to vibration and becoming unusable.

[0066] Furthermore, since the neck portion 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 less likely to wobble in the planar direction (XY direction) perpendicular to the axial direction. Therefore, it is also suppressed that the container 300 will come into contact with the blow cavity mold 141 after the mold has opened and fall off.

[0067] Subsequently, the blow core mold 143 retracts upward, and the inner core 143b is withdrawn from the neck portion 301 of the container 300. Then, the container 300 is transported by the transport chuck 161 to the removal position P3 outside the blow molding section 140 and removed. This concludes the explanation 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 undercut-shaped convex ribs 305 is manufactured. In the blow molding section 140, a preform 200 is placed in a blow cavity mold 141 having an undercut section 141c, and a blow core mold 143 is inserted inside the preform 200. Then, blow air is introduced into the preform 200 via 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 positioned inside, is gripped from the outside by a transport chuck 161, and the neck portion 301 of the container 300 is sandwiched between the blow core mold 143 and the transport chuck 161. When the blow cavity mold 141 is opened, the container 300, with its neck portion 301 held 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 container 300 is released by clamping the neck portion 301 between the blow core mold 143 and the transport chuck 161, so that the container 300 having the undercut-shaped convex rib 305 can be easily released from the blow cavity mold 141. Also, since the container 300, with its neck portion 301 clamped between the blow core mold 143 and the transport chuck 161, is less likely to wobble, it is less likely to fall off the transport chuck 161. Therefore, according to the configuration of this embodiment, the container 300 can be properly discharged from the blow molding section 140. Furthermore, with the configuration of this embodiment, it is not necessary to use a split mold with a movable insert, so the manufacturing cost of the mold can also be reduced.

[0070] Furthermore, since the container 300 is released from the blow cavity mold 141 without being forcibly removed, friction between the lower surface of the second flange 201b of the neck portion 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 with a 1.5-step or 2-step blow molding apparatus that blow-moldes the container while a part of the neck portion 301 of the preform 200 is held in the blow cavity mold 141, the occurrence of scratches on the protrusions of the neck portion 301 (support rings, annular flanges, etc.) can be suppressed.

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

[0072] For example, in the above embodiment, an example of the configuration of the blow molding section in a 1.5-step blow molding apparatus was described. However, the configuration of the blow molding section in this embodiment may also be applied to a cold parison type (2-step) blow molding apparatus that performs blow molding using a preform that has been injection molded in another 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 the embodiments, and it can be broadly applied when manufacturing a container having an undercut shape by stretch blow molding.

[0074] (First variation) Figure 12 shows an example of the configuration of the blow molding section 140 of the first modified example. In the following description, elements common to the blow molding section 140 of the embodiment are denoted by the same reference numerals, and redundant explanations are omitted. The first modified example has the same configuration as the embodiment except for the blow cavity mold 141 (or blow cavity split mold 1411, 1412) and the presence or absence of a movement allowance.

[0075] Unlike the embodiment, when the container 300 having the convex rib 305 is forcibly removed from the blow cavity mold 141, the second flange 201b on the lower side of the neck portion 301 interferes with the receiving groove (groove portion) 141b of the blow cavity mold 141. Also, the first flange 201a on the lower side of the neck portion 301 interferes with the upper surface of the blow cavity mold 141. More specifically, when forcibly removed, the entire container 300 is pushed downward by the undercut portion 141c of the cavity mold 141 as the mold opens, so the lower surface of the second flange 201b comes into strong contact with the corner of the receiving groove 141b of the cavity mold 141 (specifically, the first corner 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 can cause the underside of the second flange 201b to be rubbed, potentially resulting in uneven scratches on the underside of the second flange 201b.

[0076] Similarly, if forced removal occurs, the lower surface of the first flange 201a comes into strong contact with 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 and 1412 and the recess 141d when the blow cavity split molds 1411 and 1412 are viewed from the parting surface side). If scratches occur on the lower surface of the second flange 201b or the first flange 201a, frictional resistance increases when the second flange 201b or the first flange 201a is supported and transported by rail members or star wheels, etc., and the container 300 may get stuck and jammed during transport. In addition, scratches will also spoil the appearance of the container 300 itself.

[0077] To prevent scratches on the flange of the neck portion 301 as described above, as a first modification, for example, as shown in Figure 12, the corners (first corner region and / or second corner region) of the parting surface of the blow cavity mold 141 that come into contact with the flange of the container 300 may be beveled. Specifically, the corners at the upper end of the blow cavity mold 141 (specifically, the blow cavity split molds 1411 and 1412) through which the neck portion 301 is inserted, and the lower corners of the receiving groove 141b are beveled (i.e., the corners are chamfered in a curved shape). The two corners described above are formed on each of the blow cavity split molds 1411 and 1412.

[0078] Furthermore, 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 into which the first flange 201a fits (rests) and the recess 141d) and the lower edge of the receiving groove portion 141b (the semicircular edge in top view, formed between the lower end surface of the receiving groove portion 141b and the recess 141d) may also be machined into a curved shape. However, since this may increase the misalignment of the preform 200 relative to the blow cavity mold 141, it is preferable to set the chamfer dimension of the corners to be larger than the chamfer 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 at the locations indicated by dashed lines in Figure 12 are machined (cut and chamfered) to form a planar equilateral triangle with sides of 0.7 mm to 0.9 mm, the machined portion (planar portion) is polished to approximate a hemisphere, and finally the corners are chamfered to form a hemispherical curved surface. The edges may also be machined (cut and chamfered) by, for example, 0.1 mm to 0.2 mm, and then polished to approximate a fan shape (quarter circle shape), and finally chamfered to form a fan-shaped curved surface. 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 141a may be chamfered to form a curved surface, and the radius of curvature (radius of curvature, R or SR) of the rounded corners after processing may be set to 0.8 mm to 1.5 mm (preferably 1.0 mm to 1.2 mm). Furthermore, the edges of the receiving groove 141b and the opening 141a may also be chamfered to set the radius of curvature (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 when forced removal occurs, the lower surface of the flange of the neck portion 301 is less likely to be scraped by the corner of the blow cavity type 141, thus reducing the likelihood of scratches on the lower surface of the flange.

[0081] (Second variation) Another method to prevent scratches on the flange of the neck portion 301 is to configure the support member 145 to support the flange of the neck portion 301 when the mold is closed, and to retract the support member 145 from around the neck portion 301 before the blow cavity mold 141 opens.

[0082] Figure 13 shows an example of the configuration of the blow molding section 140 in the second modified example. In the following description, elements common to the blow molding section 140 of the embodiment are denoted by the same reference numerals, and redundant explanations are omitted. The second modified example has the same configuration as the embodiment except for the blow cavity mold 141 (or blow cavity split mold 1411, 1412) and the presence or absence of a movement allowance.

[0083] In the blow-molded section 140 of the second modified example, the support member 145 is formed thicker in the Z direction than in the above embodiment, and is configured to support the portion of the neck 301 (or neck 201) including the second flange 201b from both sides in the container height direction (Z direction). Furthermore, an annular receiving groove (groove) 145a1 is formed in the neck support portion 145a of the support member 145 to receive the second flange 201b of the neck 301.

[0084] Figure 13 shows the state when the pair of support members 145 are in the closed position. When the support members 145 are in the closed position, they are close to 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 housed in the receiving groove 145a1 of the support member 145 and the first flange 201a in contact with the upper surface of the support member 145.

[0085] In the second modification, the support member 145 is in the closed position from the moment 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. Subsequently, when the blow molding of the container 300 is completed and the container 300 is gripped by the transport chuck 161, the support member 145 slides in the Y direction (direction of arrow OP) and moves to the open position by the operation of the linear motion mechanism 146.

[0086] As a result, the support member 145 separates from the neck portion 301, and the second flange 201b no longer interferes with the receiving groove 145a1 of the support member 145. Also, the first flange 201a no longer interferes 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, preventing contact. Note that a movement allowance may or may not be formed, which allows the container 300 to move axially (downward in the Z direction) without contact between the flange and the support member 145. If a 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 descends by the distance of the movement allowance). If a movement allowance is not formed, the transport chuck 161 grips the neck portion 301 so that the container 300 cannot move downward.

[0087] Subsequently, 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 that interferes with the lower surface of the second flange 201b. Therefore, even with the configuration of the second modified example, in addition to the same effects as in the above embodiment, it is possible to prevent scratches from occurring due to interference with the lower surface member of the flange when the mold of the container 300 having the convex rib 305 is opened. Furthermore, if the transport chuck 161 supports the container 300 so that it can be moved downward, the same advantages as in the embodiment can be ensured.

[0088] Furthermore, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [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...Stretching rod, 160...Intermittent conveying section, 161...Convex chuck, 200...Preform, 201...Neck section, 201a,201b...Flange, 300...Container, 301...Neck section, 302...Shoulder section, 305...Convex rib

Claims

1. A blow-molded unit applied to the manufacture of a resin container having an annular flange on the outer circumferential surface of the neck and a convex rib-shaped undercut portion on the shoulder, The aforementioned blow-type unit is 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 each fixed, The base mold consists of a bottom cavity mold and a base mold fixing plate, The blow cavity split mold is provided with at least a pair of support members, each positioned on the upper surface side, capable of clamping and supporting the neck portion in the closed position, The blow cavity split mold has a neck portion that covers a part of the neck portion from the outside, and an undercut portion formed on the mold surface corresponding to the shoulder portion and having a shape corresponding to the convex rib. Each of the pair of support members has a neck support portion formed therein, which is notched to correspond to the outer diameter of the neck portion and has a groove for receiving the flange. The pair of support members support the container so as to lift it relative to the blow cavity splitter, and when the pair of blow cavity splitters are closed, they can move to the open position to retract the groove relative to the flange. Blow-type unit.

2. The pair of blow cavity splitters and the pair of support members have the same opening and closing direction. The blow-type unit according to claim 1.

3. The movement of the pair of support members to the open position creates a space for the container to move axially without the flange and the support members coming into contact when the pair of blow cavity split molds are opened. A blow-type unit according to claim 1 or claim 2.

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