Patent Description:
A hot parison type blow molding apparatus has been conventionally known as one of apparatuses for manufacturing a resin container. The hot parison type blow molding apparatus is configured to blow-mold a resin container using residual heat generated in injection molding of a preform, and is advantageous in that it is possible to manufacture resin containers with varieties and excellence in aesthetic appearance as compared with a cold parison type.

For example, various proposals have been made for a hot parison type blow molding cycle for the purpose of shortening the molding cycle. In order to shorten these molding cycles, it has been proposed to shorten an injection molding time of the preform in a rate-determining stage (cooling time of the preform in an injection mold), and to additionally cool the preform having high heat in a downstream step (a temperature adjusting step) after the injection molding (see, for example, Patent Literature <NUM>). In additionally cooling the preform having a high temperature in the temperature adjusting step after the injection molding, a method is also known in which heat exchange is conducted by bringing an outer circumferential surface of the preform into contact with a cooling mold, and compressed air is made to flow into the preform to cool the preform.

In addition, in this type of blow molding apparatus, for example, in order to prevent opening of a mold by blow air used for shaping a container and floating of a transport plate (also referred to as a rotary plate), it has also been proposed to provide a lock mechanism in a driving apparatus of a blow molding mold (see, for example, Patent Literatures <NUM> and <NUM>).

<CIT> discloses an injection stretching blow molding machine.

<CIT> discloses a manufacturing method for a resin container.

In a case of shortening the cooling time of the preform in the injection mold to shorten the molding cycle of the container, it is important to shorten the operation time (dry cycle) of a machine (in particular, a machine related to a temperature adjusting apparatus) as much as possible before and after cooling the preform, and to ensure a sufficient time for cooling the preform in the temperature adjusting apparatus.

In addition, when the compressed air is made to flow into the preform to cool the preform in a temperature adjusting step after the injection molding, a temperature adjusting mold may be opened vertically by the compressed air introduced into the preform. In a case where the actuator of the temperature adjusting apparatus is upsized in order to suppress such opening of the mold, the driving speed of the temperature adjusting apparatus may become lower and the operation time of the apparatus may be longer, and the time while the preform can be cooled by the temperature adjusting apparatus is reduced accordingly.

Therefore, the present invention has been made in view of such issues, and has an object to provide a blow molding apparatus capable of shortening the operation time of the machine before and after cooling the preform.

A blow molding apparatus according to one aspect of the present invention includes: an injection molding unit configured to injection-mold a preform having a bottomed shape and made of a resin; a temperature adjusting unit configured to perform a temperature adjustment of the preform by supplying the preform that has been released from the injection molding unit with cooling air; and a blow molding unit configured to blow-mold the preform after the temperature adjustment to manufacture a container made of the resin. The temperature adjusting unit includes: a first drive unit configured to drive a core mold, from which the cooling air is supplied, in a first direction to insert the core mold into the preform; a second drive unit configured to drive a cavity mold that accommodates the preform in a second direction opposite to the first direction to accommodate the preform in the cavity mold; a first lock portion configured to restrict a movement of the first drive unit in the second direction at a first position where the core mold is inserted into the preform; and a second lock portion configured to restrict a movement of the second drive unit in the first direction at a second position where the preform is accommodated in the cavity mold.

According to the present invention, the operation time of the machine can be shortened before and after cooling the preform.

In the embodiments, in order to facilitate understanding, 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 denoted by the same reference numerals. Note that the shapes, dimensions, and the like of the respective elements illustrated in the drawings are schematically illustrated, and do not indicate actual shapes, dimensions, or the like.

<FIG> is a diagram schematically illustrating a configuration of a blow molding apparatus <NUM> in the present embodiment. The blow molding apparatus <NUM> in the present embodiment is a hot parison type (also referred to as a single-stage type) apparatus that blow-molds a container by utilizing residual heat (internal heat quantity) from the injection molding without cooling a preform <NUM> (not illustrated in <FIG>) to room temperature.

The blow molding apparatus <NUM> includes an injection molding unit <NUM>, a temperature adjusting unit <NUM>, a blow molding unit <NUM>, a taking-out unit <NUM>, and a conveyance mechanism <NUM>. The injection molding unit <NUM>, the temperature adjusting unit <NUM>, the blow molding unit <NUM>, and the taking-out unit <NUM> are respectively disposed at positions rotated by a predetermined angle (for example, <NUM> degrees) around the conveyance mechanism <NUM>.

The conveyance mechanism <NUM> includes a rotary plate 26a (not illustrated in <FIG>) that rotates about an axis (Z direction) in a direction perpendicular to the sheet surface of <FIG>. The rotary plate is made up of a single disk-shaped flat plate member or a plurality of substantially fan-shaped flat plate members divided for every molding station. On the rotary plate 26a, one or more neck molds <NUM> (not illustrated in <FIG>) for holding the preform <NUM> or a resin container (hereinafter, simply referred to as a container) are arranged at every predetermined angle. The conveyance mechanism <NUM> includes a rotation mechanism, not illustrated, and rotates the rotary plate 26a to convey the preform <NUM> (or the container), the neck portion of which is held by the neck mold <NUM>, to the injection molding unit <NUM>, the temperature adjusting unit <NUM>, the blow molding unit <NUM>, and the taking-out unit <NUM> in this order. Note that the conveyance mechanism <NUM> further includes an elevation mechanism (a mechanism for opening and closing a mold vertically) and a neck mold opening mechanism, and also performs an operation of lifting up and down the rotary plate 26a and an operation related to mold closing and mold opening (mold releasing) of the preform <NUM> in the injection molding unit <NUM>.

The injection molding unit <NUM> includes an injection cavity mold and an injection core mold, the respective illustrations of which are omitted, and manufactures the preform <NUM>. An injection device <NUM> that supplies a resin material, which is a raw material of the preform <NUM>, is connected with the injection molding unit <NUM>.

In the injection molding unit <NUM>, the injection cavity mold, the injection core mold, and the neck mold <NUM> of the conveyance mechanism <NUM>, which have been described above, are closed to form a preform-shaped mold space. Then, the resin material is poured from the injection device <NUM> into such a preform-shaped mold space, and thus the preform <NUM> is manufactured by the injection molding unit <NUM>.

Here, the entire shape of the preform <NUM> is a bottomed cylindrical shape in which one end side is opened and the other end side is closed. The neck portion is formed at an end of the preform <NUM> on the opened side.

Further, the materials of the container and the preform <NUM> include a thermoplastic synthetic resin, and can be appropriately selected according to the use of the container. Specific examples of the materials include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (polycyclohexanedimethylene terephthalate), Tritan (Tritan: copolyester), PP (polypropylene), PE (polyethylene), PC (polycarbonate), PES (polyethersulfone), PPUS (polyphenylsulfone), PS (polystyrene), COP/COC (cyclic olefin-based polymer), PMMA (polymethyl methacrylate: acrylic), PLA (polylactic acid), and the like.

Note that even when the injection molding unit <NUM> is opened, the neck mold <NUM> of the conveyance mechanism <NUM> is not released, and the preform <NUM> is held and conveyed as it is. The number of the preforms <NUM> simultaneously molded by the injection molding unit <NUM> (that is, the number of containers that can be simultaneously molded by the blow molding apparatus <NUM>) can be appropriately set. As an example, in the present embodiment, it is assumed that four preforms <NUM> are conveyed in one molding cycle.

The temperature adjusting unit <NUM> equalizes the temperatures or removes the uneven temperature in the preform <NUM> that has been manufactured by the injection molding unit <NUM>, and adjusts the temperature of the preform <NUM> to a temperature suitable for blow molding (for example, about <NUM> to <NUM>). The temperature adjusting unit <NUM> also has a function of cooling the preform <NUM> in a high temperature state after the injection molding.

<FIG> is a view illustrating a configuration example of the temperature adjusting unit <NUM>.

The temperature adjusting unit <NUM> includes a core mold <NUM> (air introducing and discharging core, or temperature adjusting core) inserted into (or abutting) the preform <NUM>, and a cavity mold <NUM> (temperature adjusting pot) having a temperature adjusting space <NUM> capable of accommodating the preform <NUM>. In addition, the temperature adjusting unit <NUM> includes a first drive unit <NUM> that drives the core mold <NUM> in the vertical direction (Z direction) of <FIG>, and a second drive unit <NUM> that drives the cavity mold <NUM> in the vertical direction (Z direction) of <FIG>.

In the example of <FIG>, four preforms <NUM> are held on the rotary plate 26a by the four neck molds <NUM> provided on a neck mold fixed plate 27a attached to a lower surface of the rotary plate 26a. The temperature adjusting unit <NUM> is provided with four core molds <NUM> and four temperature adjusting spaces <NUM> of the cavity mold <NUM>. The positions of the core molds <NUM> and the temperature adjusting spaces <NUM> are respectively opposite (corresponding) to the positions of the preforms <NUM> on XY plane.

Further, the core molds <NUM> and the first drive unit <NUM> are disposed on an upper side (for example, an upper base) of the rotary plate 26a, and the cavity mold <NUM> and the second drive unit <NUM> are disposed on a lower side (for example, a machine bed (a lower base)) of the rotary plate 26a.

The core mold <NUM> is a cylindrical mold member extending in the vertical direction (Z direction) in <FIG>, and includes an air supply path (not illustrated) for introducing compressed air (cooling air) for the cooling blow into the preform <NUM>, and an exhaust path (not illustrated) for exhausting the cooling air from the preform <NUM>. Note that the cooling blow is a process of continuously causing the compressed air to flow at equal to or lower than normal temperature (<NUM>) into the inside (a hollow body portion) of the preform <NUM>, and cooling the preform <NUM> from its inner side (an inner surface) by convection of the compressed air.

Each core mold <NUM> is attached to a lower surface of the first drive unit <NUM> (specifically, a first movable plate <NUM> to be described later), and is movable in the vertical direction (Z direction) of <FIG> by the operation of the first drive unit <NUM>. In addition, the core mold <NUM> is configured to be in close contact with an inner circumference of the neck portion when inserted into the preform <NUM>, and to maintain airtightness with the preform <NUM>.

The cavity mold <NUM> is attached to an upper surface side of the second drive unit <NUM>, and is movable in the vertical direction (Z direction) of <FIG> by the operation of the second drive unit <NUM>. In addition, an opening of the temperature adjusting space <NUM> is present at an upper surface of the cavity mold <NUM>.

The temperature adjusting space <NUM> of the cavity mold <NUM> has substantially the same shape as the outer shape of the preform <NUM> that has been manufactured by the injection molding unit <NUM>. A flow path (not illustrated) along which a temperature adjusting medium flows is formed in the inside of the cavity mold <NUM>. Therefore, the temperature of the cavity mold <NUM> is maintained at a predetermined temperature by the temperature adjusting medium.

Note that the cavity mold <NUM> may be configured with, for example, a pair of split molds that are divided along the longitudinal direction of the preform and that open and close in Y direction in the drawing.

Next, a configuration of the first drive unit <NUM> of the temperature adjusting unit <NUM> will be described. <FIG> is a view illustrating the first drive unit <NUM>. In <FIG>, the illustrations of the core molds <NUM> are omitted for the sake of simplicity.

The first drive unit <NUM> includes a first movable plate <NUM>, a first fixed plate <NUM>, a shaft <NUM>, a first rod <NUM>, a first drive cylinder <NUM>, a first lock portion <NUM>, and a first stroke changing portion <NUM>.

At least two (preferably four) shafts <NUM> are attached to a lower side of the first fixed plate <NUM> in the first drive unit <NUM>. <FIG> illustrates only a pair of left and right shafts <NUM>. The shaft <NUM> extends in the vertical direction from an upper base <NUM> fixed at a predetermined height with respect to a machine bed <NUM>. The first fixed plate <NUM> is supported by the shafts <NUM>, in a state of being fixed at a predetermined height from the upper base <NUM>. In addition, the first drive cylinder <NUM> facing downward is attached to the first fixed plate <NUM>, and a pair of first rods <NUM> extending in the vertical direction are inserted through the first fixed plate <NUM>.

The first movable plate <NUM> is disposed below the first fixed plate <NUM>. Each shaft <NUM> is inserted into the first movable plate <NUM>, and the first movable plate <NUM> is movable in the vertical direction along the shafts <NUM>. In addition, as illustrated in <FIG>, the core molds <NUM> are attached to a lower surface of the first movable plate <NUM>.

A piston rod 45a, which is driven to extend by the first drive cylinder <NUM>, and first rods <NUM> are fixed to an upper surface of the first movable plate <NUM>. When the piston rod 45a extends with respect to the first drive cylinder <NUM>, the first movable plate <NUM> moves downward together with the first rods <NUM>, whereas when the piston rod 45a contracts with respect to the first drive cylinder <NUM>, the first movable plate <NUM> moves upward together with the first rods <NUM>.

Two first lock portions <NUM> are attached to an upper surface side of the first fixed plate <NUM>. Each of the first lock portions <NUM> is provided at a position corresponding to the first rod <NUM>, and includes a lock piece 46a that moves forward and backward in a horizontal direction (X direction) in the drawing, and a drive mechanism 46b that drives the lock piece 46a. Note that the configurations of the two first lock portions <NUM> are similar to each other. Therefore, the configuration of one of them will be described below, and the overlapping description of the other will be omitted.

<FIG> is a view illustrating the first lock portion <NUM> in an unlocked state, and <FIG> is a view illustrating the first lock portion <NUM> in a locked state.

In the unlocked state illustrated in <FIG>, the lock piece 46a of the first lock portion <NUM> is located at a position retracted from the position of the first rod <NUM>. In such an unlocked state, the first rod <NUM> does not interfere with the lock piece 46a, and the first movable plate <NUM> is movable in the vertical direction.

On the other hand, as illustrated in <FIG>, when the first movable plate <NUM> moves downward (in a first direction) to reach a lower end side of its stroke, an upper end of the first rod <NUM> is located on a lower side of the position of the lock piece 46a. Although the illustration is omitted, in this state, the core mold <NUM> is inserted into the preform <NUM>, and the core mold <NUM> is located at a position abutting the neck portion of the preform <NUM>, and stands still.

In this situation, the lock piece 46a of the first lock portion <NUM> can be made to move to the position of the first rod <NUM> so as to be in the locked state illustrated in <FIG>. In such a locked state, when the first movable plate <NUM> is made to move upward (in a second direction), the upper end of the first rod <NUM> abuts the lock piece 46a, and an interference occurs. For this reason, in the locked state of the first lock portion <NUM>, the lock piece 46a restricts an upward movement of the first movable plate <NUM> located on a lower end side of its stroke.

As described above, in the locked state, the upper end of the first rod <NUM> abuts the lock piece 46a, and the core molds <NUM> supported by the first movable plate <NUM> are unable to move. Accordingly, a state in which the core mold <NUM> abuts (adheres to) the preform <NUM> supported by the neck mold <NUM> is formed with certainty, and airtightness is improved. In this state, the cooling air is introduced from the core mold <NUM> into the preform <NUM>, and the cooling blow is conducted. When the cooling blow is conducted, upward force is generated in the core mold <NUM>, and the core mold <NUM> easily moves upward from the molding position. However, the upper end of the first rod <NUM> is firmly supported by the lock piece 46a. Thus, the upward movement of the core mold <NUM> is suppressed. Therefore, the preform <NUM> and the core mold <NUM> are less likely to be separated from each other, and this significantly reduces a possibility of leakage of the cooling air.

Returning to <FIG>, the first stroke changing portion <NUM> is provided between the first fixed plate <NUM> and the first movable plate <NUM>. The first stroke changing portion <NUM> includes a stopper <NUM> attached to a lower surface of the first fixed plate <NUM>, and a spacer member <NUM> attached to the upper surface of the first movable plate <NUM>. The stopper <NUM> and the spacer member <NUM> are disposed at opposite (corresponding) positions on XY plane, and are configured such that the stopper <NUM> and the spacer member <NUM> are brought into contact with each other, when the first movable plate <NUM> becomes closer to the first fixed plate <NUM>. In the examples of <FIG> and <FIG>, two first stroke changing portions <NUM> are provided between the first fixed plate <NUM> and the first movable plate <NUM>.

The stopper <NUM> is made up of, for example, a shock absorber. An upper surface side of the stopper <NUM> is fixed to the first fixed plate <NUM>, and a bottom surface side of the stopper <NUM> receives an upper surface of the spacer member <NUM>.

The spacer member <NUM> is attached to be replaceable so as to define an upper limit position (stop position when the core mold <NUM> is retracted) within a movement range of the first movable plate <NUM>. The spacer member <NUM> is, for example, a block having a rectangular overall shape, and is fixed to the first movable plate <NUM> with a bolt or the like.

As the spacer member <NUM>, a member having a given height is selectable from a plurality of types with different heights in the vertical direction so that the movement range of the first movable plate <NUM> has appropriate dimensions for moving the core mold <NUM> forward and backward. For example, the dimensions of the spacer member <NUM> are selected so that the core mold <NUM> completely comes out of the preform <NUM> at the time of moving backward and does not interfere with the rotary plate 26a, and a movement amount of the core mold <NUM> is minimized.

As an example, <FIG> illustrates a state in which a spacer member 49a having a height different from that of <FIG> is attached. A height ha2 of the spacer member 49a in <FIG> is larger than a height ha1 of the spacer member <NUM> in <FIG> (ha2 > ha1). Accordingly, in the case of <FIG>, the stopper <NUM> and the spacer member 49a are brought into contact with each other, when the first movable plate <NUM> is located at a position lower than that in <FIG>. Therefore, the movement range of the first movable plate <NUM> is reduced. That is, in a case where the preform <NUM> is short, the movement amount of the core mold <NUM> is reduced with use of the spacer member 49a that is long, whereas in a case where the preform <NUM> is long, the movement amount of the core mold <NUM> is increased with use of the spacer member <NUM> that is short. With this configuration, the movement amount (stroke amount) of the core mold <NUM> is optimally adjustable in accordance with the length of the preform <NUM>.

Subsequently, a configuration of the second drive unit <NUM> of the temperature adjusting unit <NUM> will be described. <FIG> is a diagram illustrating the second drive unit <NUM>. In <FIG>, the illustration of the cavity mold <NUM> is omitted for the sake of simplicity.

The second drive unit <NUM> includes a second movable plate <NUM>, a second fixed plate <NUM>, a second rod <NUM>, a second drive cylinder <NUM>, a second lock portion <NUM>, and a second stroke changing portion <NUM>.

The second fixed plate <NUM> in the second drive unit <NUM> is fixed on the machine bed (lower base) <NUM>. The second drive cylinder <NUM> facing upward is attached to the second fixed plate <NUM>, and at least two (preferably, two pairs of (four)) second rods <NUM> extending in the vertical direction are inserted through the second fixed plate <NUM>. <FIG> illustrates the second drive unit <NUM> in which two pairs of (four) second rods <NUM> are provided. In <FIG>, only one pair of the two pairs of the second rods <NUM> arranged in parallel in the depth direction (Y direction) in the drawing in the second drive unit <NUM> is illustrated.

The second movable plate <NUM> is disposed above the second fixed plate <NUM>. The second movable plate <NUM> is supported from below by two or more (for example, four) shafts (not illustrated) extending in the vertical direction, and is movable in the vertical direction along the shafts. In addition, as illustrated in <FIG>, the cavity mold <NUM> is attached to an upper surface of the second movable plate <NUM>.

A piston rod 55a, which is driven to extend by the second drive cylinder <NUM>, and second rods <NUM> are fixed to a lower surface of the second movable plate <NUM>. When the piston rod 55a extends with respect to the second drive cylinder <NUM>, the second movable plate <NUM> moves upward together with the second rod <NUM>, whereas when the piston rod 55a contracts with respect to the second drive cylinder <NUM>, the second movable plate <NUM> moves downward together with the second rod <NUM>.

Two second lock portions <NUM> are attached to an upper surface side of the second fixed plate <NUM>. Each of the second lock portions <NUM> is provided at a position where the second rod <NUM> is disposed in the horizontal direction (X direction) in the drawing, and includes a lock piece 56a that moves forward and backward in X direction, and a drive mechanism 56b that drives the lock piece 56a. The drive mechanism 56b includes a drive rod 56e, and the drive rod 56e and the lock piece 56a are coupled with each other through a free joint 56d. Note that the configurations of the two second lock portions <NUM> are similar to each other. Therefore, the configuration of one of them will be described below, and the overlapping description of the other will be omitted.

<FIG> is a view illustrating the second lock portion <NUM> in an unlocked state, and <FIG> is a view illustrating the second lock portion <NUM> in a locked state.

In the unlocked state illustrated in <FIG>, the lock piece 56a of the second lock portion <NUM> is located at a position retracted from the position of the second rod <NUM>. In such an unlocked state, the second rod <NUM> does not interfere with the lock piece 56a, and the second movable plate <NUM> is movable in the vertical direction.

On the other hand, as illustrated in <FIG>, when the second movable plate <NUM> moves upward (in the second direction) to reach an upper end side of its stroke, a lower end of the second rod <NUM> is located on an upper side of the position of the lock piece 56a. Although the illustration is omitted, in this state, the preform <NUM> is accommodated in the cavity mold <NUM>, and the cavity mold <NUM> is located at a position abutting the neck mold <NUM>, and stands still.

In this situation, the lock piece 56a of the second lock portion <NUM> can be made to move to the position of the second rod <NUM> so as to be in the locked state illustrated in <FIG>. In such a locked state, when the second movable plate <NUM> is made to move downward (in the first direction), the lower end of the second rod <NUM> abuts the lock piece 56a, and an interference occurs. For this reason, in the locked state of the second lock portion <NUM>, the lock piece 56a restricts a downward movement of the second movable plate <NUM> located on an upper end side of its stroke.

Here, the basic configuration of the second lock portion <NUM> is similar to that of the first lock portion <NUM>, but is different in that inclined surfaces are formed on an upper surface side of a receiving portion 56c that receives the lock piece 56a and a lower surface side of the lock piece 56a.

Specifically, a surface 56c1 of the receiving portion 56c that receives the lock piece 56a and a lower surface 56a1 of the lock piece 56a each have a wedge-shaped inclined surface inclined upward in a direction that the lock piece 56a extends. For this reason, as illustrated in <FIG>, when the lock piece 56a of the second lock portion <NUM> is extended, the surface 56c1 of the receiving portion 56c is pressed against the lower surface 56a1 of the lock piece 56a, upward reaction force is generated, and the movement of the lock piece 56a in the extending direction is converted into upward force. In addition, the free joint 56d is provided between the lock piece 56a and the drive mechanism 56b (drive rod 56e). Therefore, a behavior that the drive mechanism 56b (drive rod 56e) that moves forward and backward in X direction becomes eccentric or inclined in Z direction can be suppressed, and only the lock piece 56a can be smoothly moved in the upward direction by a predetermined amount, while breakage of the drive mechanism 56b is suppressed.

As described above, when the lower end of the second rod <NUM> is pushed up by the lock piece 56a in the locked state, the cavity mold <NUM> supported by the second movable plate <NUM> is also pushed up. Accordingly, a state in which the cavity mold <NUM> firmly abuts (is in close contact with) the neck mold <NUM> of the rotary plate 26a is formed. In this state, the preform <NUM> held by the neck mold <NUM> is accommodated in the cavity mold <NUM>. Next, the temperature adjusting unit <NUM> introduces the cooling air into the preform <NUM> (conducts cooling blow). When the cooling blow is conducted, downward force is generated in the cavity mold <NUM>, and the cavity mold <NUM> easily moves downward from the molding position. However, the lower end of the second rod <NUM> is firmly supported by the lock piece 56a. Thus, the downward movement (mold opening) of the cavity mold <NUM> is suppressed. Therefore, misalignment (core misalignment or the like) hardly occurs between the preform <NUM> and the cavity mold <NUM>, and a possibility that the preform <NUM> is brought into contact with the cavity mold <NUM> in a misaligned state at the time of the cooling blow and an appropriate temperature adjustment cannot be made is largely reduced. Note that the downward force received by the cavity mold <NUM> caused by the cooling air is transmitted from the lower end of the second rod <NUM> to the lock piece 56a, and becomes horizontal force to push back the lock piece 56a along the surface 56c1 of the receiving portion 56c. Hence, it is necessary to set the horizontal force of the drive mechanism 56b to be larger than the horizontal force generated in the receiving portion 56c by the cooling air.

Returning to <FIG>, the second stroke changing portion <NUM> is provided between the machine bed <NUM> and the second movable plate <NUM>. The second stroke changing portion <NUM> includes a stopper <NUM> attached to the machine bed <NUM>, and a spacer member <NUM> attached to a lower surface of the second movable plate <NUM>. The stopper <NUM> and the spacer member <NUM> are disposed at opposite (corresponding) positions on XY plane, and are configured such that the stopper <NUM> and the spacer member <NUM> are brought into contact with each other, when the second movable plate <NUM> is brought to be closer to the machine bed <NUM>. In the examples of <FIG> and <FIG>, two stroke changing portions <NUM> are provided between the machine bed <NUM> and the second movable plate <NUM>. Note that the stopper <NUM> may be provided on the second fixed plate <NUM> that is contiguous with the machine bed <NUM> and that supports the second movable plate <NUM> to be movable.

The stopper <NUM> is made up of, for example, a shock absorber. A lower surface side of the stopper <NUM> is fixed to the machine bed <NUM>, and an upper surface side receives a bottom surface of the spacer member <NUM>.

The spacer member <NUM> is attached to be replaceable so as to define a lower limit position (stop position when the cavity mold <NUM> is retracted) within a movement range of the second movable plate <NUM>. The spacer member <NUM> is, for example, a block having a rectangular overall shape, and is fixed to the second movable plate <NUM> with a bolt or the like.

As the spacer member <NUM>, a member having a given height is selectable from a plurality of types with different heights in the vertical direction so that the movement range of the second movable plate <NUM> has appropriate dimensions for moving the cavity mold <NUM> forward and backward. For example, the dimensions of the spacer member <NUM> are selected so that the preform <NUM> completely comes out of the cavity mold <NUM> at the time of moving backward, an interference does not occur, and the movement amount of the cavity mold <NUM> is minimized.

As an example, <FIG> illustrates a state in which a spacer member 59a having a different height from that of <FIG> is attached. A height hb2 of the spacer member 59a in <FIG> is larger than a height hb1 of the spacer member <NUM> in <FIG> (hb2 > hb1). Accordingly, in the case of <FIG>, the stopper <NUM> and the spacer member 59a are brought into contact with each other, when the second movable plate <NUM> is located at a position higher than the position in <FIG>. Therefore, the movement range of the second movable plate <NUM> is reduced. That is, in a case where the preform <NUM> is short, the movement amount of the cavity mold <NUM> is reduced with use of the spacer member 59a that is long, whereas in a case where the preform <NUM> is long, the movement amount of the cavity mold <NUM> is increased with use of the spacer member <NUM> that is short. With this configuration, the movement amount (stroke amount) of the cavity mold <NUM> is optimally adjustable in accordance with the length of the preform <NUM>.

Returning to <FIG>, the blow molding unit <NUM> blow-molds the preform <NUM>, the temperature of which has been adjusted by the temperature adjusting unit <NUM>, to manufacture a container.

The blow molding unit <NUM> includes blow cavity molds that are a pair of split molds corresponding to the shape of the container, an air introduction member that also serves as a stretching rod (neither of them is illustrated), and an exhaust path (not illustrated in <FIG>) for exhausting the blow air from the inside of the container. The blow molding unit <NUM> blow-molds the preform <NUM> while stretching the preform. Accordingly, the preform <NUM> can be shaped into a blow cavity shape, and a container can be manufactured.

The taking-out unit <NUM> is configured to release the neck portion of the container that has been manufactured by the blow molding unit <NUM> from the neck mold, and to take out the container to the outside of the blow molding apparatus <NUM>.

<FIG> is a flowchart illustrating steps of a blow molding method performed by the blow molding apparatus <NUM> in the present embodiment. In the present embodiment, before the respective steps (S101 to S104) to be described later of the blow molding method are performed, a stroke changing step (S1 to S2) of changing the ranges of movements of the first drive unit <NUM> and the second drive unit <NUM> in the temperature adjusting unit is performed.

In the stroke changing step, the following work is performed when the movement range of the first drive unit <NUM> is changed.

First, a value is obtained by subtracting a stroke necessary for inserting and extracting the core mold <NUM> from a value of a maximum movement range of the first drive unit <NUM>. Then, a member having a height corresponding to the above obtained value is prepared as the spacer member <NUM> to be used in the first drive unit <NUM> (S1: a preparing step of a spacer member). Then, the spacer member <NUM> that has been prepared is attached to the upper surface of the first movable plate <NUM> (S2: an attaching step of the spacer member). Accordingly, the movement range of the first drive unit <NUM> becomes the same with the stroke necessary for inserting and extracting the core mold <NUM>.

Similarly, in the stroke changing step, the following work is performed when the movement range of the second drive unit <NUM> is changed.

First, a value is obtained by subtracting a stroke necessary for inserting and extracting the preform <NUM> from the cavity mold <NUM> from a value of a maximum movement range of the second drive unit <NUM>. Then, a member having a height corresponding to the above obtained value is prepared as the spacer member <NUM> to be used in the second drive unit <NUM> (S1: the preparing step of the spacer member). Then, the spacer member <NUM> that has been prepared is attached to the lower surface of the second movable plate <NUM> (S2: the attaching step of the spacer member). Accordingly, the movement range of the second drive unit <NUM> becomes the same with the stroke necessary for inserting and extracting the preform <NUM> from the cavity mold <NUM>.

When the stroke changing step is completed, the respective steps (blow molding cycle) in the blow molding method to be described below are performed. Note that the stroke changing step is desirably performed simultaneously with the step of attaching a mold for the injection molding unit, a mold for the temperature adjusting unit, a mold for the blow molding unit, and a mold for the taking-out unit to the blow molding apparatus <NUM>.

First, in the injection molding unit <NUM>, a resin is injected from the injection device <NUM> into a preform-shaped mold space formed with the injection cavity mold, the injection core mold, and the neck mold <NUM> of the conveyance mechanism <NUM>, and the preform <NUM> is manufactured.

In step S101, the injection molding unit <NUM> is opened immediately after filling of the resin ends or after a minimum cooling time provided after the resin is filled. That is, the preform <NUM> in a high temperature state in which the outer shape of the preform <NUM> can be maintained is released from the injection cavity mold and the injection core mold. Then, the rotary plate 26a of the conveyance mechanism <NUM> rotates by a predetermined angle, and the preform <NUM> held by the neck mold <NUM> is conveyed to the temperature adjusting unit <NUM>.

Here, a temperature change of the preform <NUM> in the blow molding method in the present embodiment will be described with reference to <FIG>. The vertical axis of <FIG> represents the temperature of the preform, and the horizontal axis of <FIG> represents the time. In <FIG>, an example of temperature changes of the preform in the present embodiment is indicated by (A) of <FIG>. In addition, an example of temperature changes of a preform in a comparative example (conventional method) to be described later is indicated by (B) of <FIG>. Note that blanks between the respective steps mean the time required to convey the preform or the container, and are identical to one another.

In the present embodiment, when a resin material is injected at a temperature equal to or higher than the melting point of the resin material, the injection molding unit <NUM> conducts only minimum cooling of the preform <NUM> that has been subjected to the injection molding, and the temperature adjusting unit <NUM> cools the preform <NUM> and adjusts the temperature of the preform <NUM>. In the present embodiment, after the injection molding unit <NUM> completes the injection of the resin material, the time (cooling time) for cooling the resin material is preferably <NUM>/<NUM> or less the time (injection time) for injecting the resin material. In addition, the time for cooling the resin material can be made shorter than the time for injecting the resin material in accordance with the weight of the resin material. The time for cooling the resin material is more preferably <NUM>/<NUM> or less, still more preferably <NUM>/<NUM> or less, and particularly preferably <NUM>/<NUM> or less the time for injecting the resin material. The cooling time is significantly shortened as compared with that in the comparative example. Thus, a skin layer (surface layer in a solidified state) of the preform is formed thinner than a conventional one, and a core layer (inner layer in a softened or molten state) is formed thicker than the conventional one. That is, as compared with the comparative example, a preform having a large thermal gradient between the skin layer and the core layer and having high residual heat at a high temperature is formed.

In the present embodiment, the preform that has been injection-molded is released from the injection molding unit <NUM> at a higher release temperature than that in the comparative example, and is conveyed to the temperature adjusting unit <NUM>. With the movement to the temperature adjusting unit <NUM>, the temperature of the preform is equalized by heat exchange (heat conduction) between the skin layer and the core layer. Further, the preform is slightly cooled from the outer surface by contact with the outside air. However, the temperature of the preform is maintained at a substantially high release temperature, until the preform is conveyed to the temperature adjusting unit <NUM>. In the temperature adjusting unit <NUM>, the temperature of the preform decreases from the high release temperature to a blow temperature, and then the temperature of the preform is maintained at the blow temperature until blow molding is conducted.

Note that the blow temperature is a temperature suitable for the blow molding, and is set to <NUM> to <NUM> for a PET resin, for example. However, a lower blow temperature makes the stretching orientation of the preform better, and is capable of enhancing the strength (physical property) of the container. For this reason, the blow temperature is preferably set to <NUM> to <NUM> for a PET resin, for example.

Here, due to the structure of the blow molding apparatus <NUM>, the injection molding step, the temperature adjusting step, the blow molding step, and the container taking-out step respectively have the same lengths of time. Similarly, the conveyance times between the respective steps are the same.

On the other hand, as the comparative example, a description will be given with regard to an example of temperature changes of the preform ((B) of <FIG>) in a case where the preform is cooled in the injection molding step.

In the comparative example, the preform is cooled to a temperature lower than or substantially the same as the blow temperature in the mold of the injection molding unit <NUM>. As a result, in the comparative example, the time of the injection molding step is longer than that in the present embodiment. In such a case, the times of the respective steps are set in accordance with the time of the longest injection molding step. Hence, the time of the molding cycle of the container also becomes long as a result.

Subsequently, the temperature adjusting unit <NUM> makes a temperature adjustment for bringing the temperature of the preform <NUM> close to a temperature suitable for a final blow.

In the temperature adjusting step, first, driving of the second drive unit <NUM> causes the preform <NUM> to be accommodated in the temperature adjusting space <NUM> of the cavity mold <NUM>. In this situation, the second lock portion <NUM> is in the locked state, and the downward movement of the cavity mold <NUM> supported by the second movable plate <NUM> is restricted.

Subsequently, driving of the first drive unit <NUM> causes the core mold <NUM> to be inserted into the preform <NUM>. In this situation, the first lock portion <NUM> is in the locked state, and the upward movement of the core mold <NUM> supported by the first movable plate <NUM> is restricted.

After that, the cooling air is introduced into the preform <NUM> from the air supply path of the core mold <NUM>, and the cooling air is exhausted from the exhaust path of the core mold <NUM> (the cooling blow is conducted). The preform <NUM> is cooled from the inside by such convection of the cooling air. In this situation, the preform <NUM> is continuously in contact with the cavity mold <NUM>. Therefore, the temperature of the preform <NUM> is adjusted and the preform <NUM> is cooled so that the temperature does not become equal to or lower than a temperature suitable for the blow molding from the outside, and the uneven temperature generated from injection molding is also reduced. Note that the temperature adjusting space <NUM> of the cavity mold <NUM> has substantially the same shape as the preform <NUM>, and the shape of the preform <NUM> does not change greatly in the temperature adjusting unit <NUM>. Note that the cavity mold <NUM> may be configured with a pair of split molds, and a preliminary blow (a process of temporarily bulging the preform to a size smaller than the container with the compressed air before the final blow) may be conducted before the cooling blow.

When the cooling and the temperature adjustment of the preform <NUM> end, the locked states of the first lock portion <NUM> and the second lock portion <NUM> are both released, and the cavity mold <NUM> and the core mold <NUM> are retracted. Then, the rotary plate 26a of the conveyance mechanism <NUM> rotates by a predetermined angle, and the preform <NUM> that has been subject to the temperature adjustment and that is held by the neck mold <NUM> is conveyed to the blow molding unit <NUM>.

Subsequently, the container is blow-molded in the blow molding unit <NUM>.

First, the blow molding mold is closed to accommodate the preform <NUM> in the mold space, and the blow core mold and the stretching rod are inserted into the neck portion of the preform <NUM>. Then, the blow air is introduced into the preform <NUM> from the blow core mold while the stretching rod is being moved down. Accordingly, the preform <NUM> is bulged and shaped to be in close contact with the mold space of the blow molding mold, and is blow-molded into a container.

When the blow molding ends, the blow molding mold is opened. Accordingly, the container becomes movable from the blow molding unit <NUM>.

Subsequently, the rotary plate 26a of the conveyance mechanism <NUM> rotates by a predetermined angle, and the container is conveyed to the taking-out unit <NUM>. In the taking-out unit <NUM>, the neck portion of the container is released from the neck mold <NUM>, and the container is taken out to the outside of the blow molding apparatus <NUM>.

Heretofore, a series of steps in the blow molding method ends. Then, the rotary plate 26a of the conveyance mechanism <NUM> is rotated by a predetermined angle, so that the respective steps of S101 to S104 described above are repeated.

Hereinafter, advantages of the blow molding apparatus and the blow molding method in the present embodiment will be described.

In a case where a hot parison type preform is molded with a crystalline thermoplastic resin (a resin that can be in a transparent amorphous state or a cloudy crystalline state) used as a material, whitening (cloudiness) may occur due to insufficient cooling depending on the material. For example, in a case where a PET resin is used as a material, when the preform is slowly cooled (for example, cooled at room temperature for several tens of seconds) in a temperature zone (<NUM> to <NUM>) in which crystallization is promoted, crystallization due to spherulite formation occurs, and the preform tends to be whitened.

For this reason, conventionally, the injection molding mold of the preform is rapidly cooled (for example, at <NUM> for five seconds) to shorten the passage time in the above crystallization temperature zone, and the preform is sufficiently cooled in the injection molding step to suppress whitening of the preform.

On the other hand, according to the blow molding method in the present embodiment, the step of cooling the preform <NUM> is almost eliminated in the injection molding step (S101), and the preform is cooled in the temperature adjusting step (S102). In the temperature adjusting step (S102), by introducing the cooling air into the preform <NUM> and also bringing the preform <NUM> into close contact with the cavity mold <NUM>, the preform <NUM> can be cooled simultaneously with the temperature adjustment of the preform <NUM>. In the present embodiment, the temperature adjustment and cooling of the preform <NUM> can be conducted in the temperature adjusting step (S102). Thus, it is possible to release the preform <NUM> even in a high temperature state in the injection molding step (S101), and to start molding the next preform <NUM> early. That is, according to the present embodiment, the container can be favorably molded, while the molding cycle time is shortened as compared with the molding cycle time in the comparative example.

Further, according to the blow molding method in the present embodiment, in the stroke changing step (S1 to S2), the movement range of the first drive unit <NUM> is adjusted to a stroke necessary for inserting and extracting the core mold <NUM> and the movement range of the second drive unit <NUM> is adjusted to a stroke necessary for inserting and extracting the preform <NUM> from the cavity mold <NUM>.

Accordingly, the strokes of the first drive unit <NUM> and the second drive unit <NUM> of the temperature adjusting unit <NUM> can be optimized in accordance with the dimensions of the preform, and the first drive unit <NUM> and the second drive unit <NUM> do not have to be moved excessively in the temperature adjusting step (S102), as compared with a case where such adjustments are not made. Therefore, in the present embodiment, the operation time of the machine is shortened before and after the temperature adjustment and cooling of the preform <NUM>.

In other words, by shortening the operation time of the machine in the temperature adjusting step, the time for temperature adjustment and cooling of the preform <NUM> becomes extendable within a certain molding cycle time accordingly. Therefore, according to the present embodiment, the cooling effect of the preform <NUM> in the temperature adjusting step is enhanced, and thus the molding cycle time is easily shortened.

In addition, according to the present embodiment, when the cooling air is introduced into the preform <NUM> for cooling in the temperature adjusting step, the upward movements of the core mold <NUM> and the first movable plate <NUM> are restricted by the operation of the first lock portion <NUM>, and the downward movements of the cavity mold <NUM> and the second movable plate <NUM> are restricted by the operation of the second lock portion <NUM>.

Accordingly, the mold opening of the core mold <NUM> or the cavity mold <NUM> is suppressed, when the cooling air is introduced into the preform <NUM> in the temperature adjusting step. In addition, it is not necessary to upsize the actuator as a countermeasure for the mold opening described above. The first lock portion <NUM> and the second lock portion <NUM> enable an enhancement in the mold holding force of the temperature adjusting unit <NUM>, as compared with a standard case without these configurations.

That is, according to the present embodiment, the mold opening of the core mold <NUM> or the cavity mold <NUM> can be suppressed, while a decrease in the operation speed of the apparatus in accordance with upsizing of the actuator is avoided. Moreover, according to the present embodiment, a decrease in the operation speed and an increase in the occupied space in accordance with the upsizing of the actuator can be avoided.

The present invention is not limited to the above embodiments, and various improvements and design changes may be made without departing from the scope of the appended claims.

Claim 1:
A blow molding apparatus (<NUM>) comprising:
an injection molding unit (<NUM>) configured to injection-mold a preform (<NUM>) having a bottomed shape and made of a resin;
a temperature adjusting unit (<NUM>) configured to perform a temperature adjustment of the preform (<NUM>) by supplying the preform (<NUM>) that has been released from the injection molding unit (<NUM>) with cooling air; and
a blow molding unit (<NUM>) configured to blow-mold the preform (<NUM>) after the temperature adjustment to manufacture a container made of the resin, wherein
the temperature adjusting unit (<NUM>) includes:
a first drive unit (<NUM>) configured to drive a core mold (<NUM>), from which the cooling air is supplied, in a first direction to insert the core mold (<NUM>) into the preform (<NUM>);
a second drive unit (<NUM>) configured to drive a cavity mold (<NUM>) that accommodates the preform (<NUM>) in a second direction opposite to the first direction to accommodate the preform (<NUM>) in the cavity mold (<NUM>);
a first lock portion (<NUM>) configured to restrict a movement of the first drive unit (<NUM>) in the second direction at a first position where the core mold (<NUM>) is inserted into the preform (<NUM>); and
a second lock portion (<NUM>) configured to restrict a movement of the second drive unit (<NUM>) in the first direction at a second position where the preform (<NUM>) is accommodated in the cavity mold (<NUM>).