JP4540721B2 - Blow molding machine - Google Patents

Description

  The present invention relates to a blow molding machine having a heating station and a blow molding station.

  In general, as a blow molding machine, a biaxial stretch blow molding machine for molding a thin synthetic resin container such as a PET bottle is known.

  The present applicant has previously proposed a blow molding machine for molding a heat-resistant synthetic resin container as disclosed in Patent Document 1.

  This blow molding machine is supplied with a preform, a heating station for heating the preform supplied from the supply unit, a transfer unit for transferring the preform heated by the heating station, and a transfer unit. A blow molding station for blow molding the preform to mold the container is disposed on the machine base. The heating station has a plurality of linear heating conveyance paths arranged in parallel. The heating conveyance path has one end coupled to the supply unit and the other end coupled to the transfer unit. The blow molding station has a substantially rectangular second conveyance path coupled to a transfer unit that intermittently conveys the preform delivered at the same time. Further, the second conveyance path is formed by blow-molding the preform to perform primary molding. A primary blow molding part for molding a molded product, a primary heat treatment part for bringing the primary molded product into contact with the inner surface of the heat treatment mold and heat-treating, a secondary heat treatment part for heat-treating the intermediate molded product after the primary heat treatment outside the mold, A final blow molding section is provided that blow-molds the intermediate molded product that has undergone the subsequent heat treatment into the shape of a container that is the final molded product.

  The blow conveying path of this blow molding machine has a substantially rectangular shape having a short side and a long side with a blow conveying chain spanning four sprockets arranged at the corners of the conveying path. During the conveyance of the delivered preform to the long side, it was necessary to convey the preform at a speed at which the preform did not fall off the holder due to the centrifugal force at the corner of the conveyance path. In addition, since the transport is performed by a chain, in the case of a mass production machine, if the second transport path becomes longer, a periodic check of the chain tension is indispensable in consideration of the chain elongation.

  Therefore, the applicant of the present application has proposed a mass production type linear conveyance type blow molding machine that employs linear conveyance as shown in Patent Document 2 without using chain conveyance.

  This linear transport type blow molding machine has been able to greatly improve the above-mentioned problems of chain transport, particularly the transport speed, by adopting linear transport using a pallet-type blow transport member. However, in this improved linear conveyance type blow molding machine, the direction of the pallet in the heating conveyance path and the direction of the pallet in the blow conveyance path are the same, which complicates the structure of the heating conveyance path and further increases the heating conveyance. There was a problem due to thermal expansion of the pallet on the road. The problem due to thermal expansion is that the pallet is circulated and transported along a rectangular heating transport path having a forward path and a return path on a plane, and thus a heating device (heating box) is arranged over almost the entire area of the forward path and the return path. Therefore, there is a conveyance trouble that occurs when the pallet is gradually heated and thermally expanded during continuous molding.

In addition, this linear conveyance type blow molding machine has two rows of blow forward paths along the side of the machine base as blow conveyance paths, and two rows arranged above the mold clamping mechanism on the center line of the machine base. Blow return path and are arranged.
JP-A-10-264240 JP 2001-88203 A

  The objective of this invention is providing the blow molding machine which solved the trouble of conveyance of a heating conveyance path while simplifying the structure of a heating conveyance path.

  Another object of the present invention is to provide a blow molding machine with a simplified structure of the blow conveyance path.

  In order to achieve the above object, one aspect of the present invention includes a heating station that heats a preform, a transfer unit that transfers the heated preforms N (N ≧ 2) to the blow molding station, and the transfer In a blow molding machine having a blow molding station for simultaneously molding N preforms received from a section to form N synthetic resin containers, the heating station converts the N preforms into a first A heating forward path for transporting a plurality of heating conveying members arranged and supported in a direction along a second direction orthogonal to the first direction, and a lower part of the heating forward path, the heating path A heating return path provided in parallel with the forward path and the heating transport section from the heating forward path toward the heating return path at one end of the heating forward path located on the transfer unit side A lowering mechanism that lowers the heating conveying member at the other end of the heating outward path from the heating backward path toward the heating outward path, and the heating backward path The heating conveying members, which are smaller in number than the heating conveying members arranged in the heating outward path, are conveyed in the direction opposite to the second direction and conveyed along the heating backward path. The heating conveying member is allowed to cool or forcibly cool.

In another aspect of the present invention, a heating station that heats the preform on the machine base, two transfer units that respectively transfer the heated preforms to the blow molding station by N (N ≧ 2), In the blow molding machine having two blow molding stations for simultaneously molding the N preforms received from the two transfer units to form each of the N synthetic resin containers, the two blow molding stations Is provided along a plurality of blow conveying members that support and convey the N preforms received from the transfer unit, and two side edges on the machine base, and the plurality of blow conveying members are Between the two rows of blow return paths to be returned and the two rows of blow return paths on the machine base, the two rows of blow returns in the same horizontal plane as the two rows of blow return paths. 2 columns and forward for blow of which is provided in parallel with,
Each of the two transfer units includes a gripping mechanism for gripping N preforms arranged in the first direction, and rotating the gripping mechanism to align the N preforms in the second direction. A direction changing mechanism for changing, wherein the gripping mechanism has N sets of gripping members for gripping the N preforms and a lifting cylinder for lifting and lowering the N sets of gripping members, and the two transfer units In each of the direction changing mechanisms, the turning center position is arranged between the two rows of blow outward paths, and the arrangement positions of the N preforms rearranged by the respective direction changing mechanisms are the two rows. It corresponds to each position on the forward path for blow.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIGS. 1-6 is a figure which shows the molding machine (henceforth a molding machine) 1 of the heat resistant synthetic resin container using the blow molding machine which concerns on one implementation of this invention.

  FIG. 1 is a plan view showing the overall configuration of the molding machine 1, and FIG. 2 is a side view thereof. In FIG. 1, the heating device and the cooling device are omitted in the upper half of the drawing in order to explain the conveyance state of the heating station 4. Further, in FIG. 2, the blow conveyance path is omitted.

  In this molding machine 1, a supply unit 3, a heating station 4, a transfer unit 5, a blow molding station 6, and a take-out unit 10 are roughly arranged in two rows along the transport direction A on a machine base 2. It is arranged in a straight line. Since the configuration of each of the two sets of units / stations is basically the same, the following description will mainly describe the lower set of FIG.

  The supply unit 3 supplies the preform P from outside the molding machine 1 to the heating station 4, and includes a supply rail 16, an alignment mechanism 17 shown in FIG. 3, and a reverse delivery mechanism 18.

  A plurality of preforms P arranged in a line in a direction orthogonal to the conveying direction A by the alignment mechanism 17 (not shown in detail) of the supply unit 3 are used by the reverse delivery mechanism 18 as shown in FIG. In the embodiment, six are reversed at the same time and handed over to the heating station 4 in an inverted state.

  As shown in FIGS. 1 and 2, the heating station 4 heats the preform P delivered from the supply unit 3 in an inverted state, and supports and conveys the preform P. A heating conveyance path 20 that circulates and conveys the heating conveyance member 21 intermittently, a heating box 37 that includes an infrared heater 38 (see FIG. 3) for heating the preform P, and air on the surface of the preform P. And a cooling box 40 for cooling by spraying.

  3 and 4 omit the heating box 37 and the cooling box 40 in order to show the heating conveyance path 20. The heating conveyance member 21 is guided by guide rails at both ends thereof and transferred through the heating conveyance path 20. In this embodiment, the holder 24 supports the mouths of the six preforms P on the upper surface. And a sprocket 25 for rotating each holder 24 on the lower surface. The sprocket 25 receives a driving force of an unillustrated motor for rotation by a belt, and rotates the preform P in the heating unit together with the holder 24. By rotating the preform P, the light from the infrared heater 38 can be evenly applied in the circumferential direction.

  The heating conveyance path 20 includes a heating conveyance path 20a in which a plurality of heating conveyance members 21 are arranged along the conveyance direction A (18 in this embodiment) and a heating conveyance member below the heating conveyance path 20a. And a heating return path 20b for returning 21 to the supply unit 3 side (the reverse direction of the conveying direction A).

  The heating outward path 20 a is a conveyance path for heating the preform P to an appropriate temperature while conveying the heating conveyance member 21, and a set of heating outward path guide rails 22 extending along the conveyance direction A. And a heating outbound drive means 26 comprising an air cylinder that pushes the heating conveying member 21 disposed at the end of the heating outbound path 20a on the supply unit 3 side in the conveying direction A by one heating conveying member. ing.

  The heating return path 20b is a conveyance path for delivering the preform P to the transfer section 5 and returning the heating conveyance member 21 emptied to the supply section 3 side, and is a set of heating lines extending along the conveyance direction A. A return path guide rail 23 (see FIG. 5) and a heating return path driving means 27 that intermittently conveys the heating conveyance member 21 in the direction opposite to the conveyance direction A are provided. The heating return path drive means 27 includes two positioning rods 31, a heating return path drive rod 33, and a heating return path rotation cylinder 34 that rotates these rods by 90 degrees. The heating return path drive rod 33 and the positioning rod 31 have heating engagement pieces 35 that are engaged with both side surfaces of the heating conveyance member 21 one set at five locations at regular intervals. Can be held in place.

  At the delivery position on the transfer section 5 side of the heating forward path 20a, there is a heating lowering mechanism 28 for lowering the heating transport member 21 from the heating forward path 20a to the heating return path 20b.

  On the supply section 3 side of the heating return path 20b, there is a heating raising mechanism 29 that raises the heating transport member 21 from the heating return path 20b to the heating forward path 20a.

  As shown in FIGS. 5 and 6, the transfer unit 5 has a gripping mechanism 50 that grips the six heated preforms P conveyed to the end (delivery position) on the transfer unit 5 side of the heating forward path 20 a. And a direction changing mechanism 53 that transfers the preform P gripped by the gripping mechanism 50 to the upper side of the blow conveying member of the blow molding station 6 while changing the alignment direction of the preform P by 90 degrees.

  As shown in FIG. 1, the transfer unit 5 is positioned between the two sets of blow conveyance paths 60. As shown in FIGS. 5 and 6, the direction changing mechanism 53 includes a frame (not shown) erected on the machine base 2, and two arms 54 that extend toward the two heating units at the upper end of the frame. Two servo motors (built in a frame (not shown)) for rotating the rotation shafts 55 of the two arms 54 are provided.

  The gripping mechanism 50 is provided at the tip of the arm 54 and opens and closes six sets of gripping members 51 that grip the neck portions of the preforms P from both sides, and the six sets of gripping members 51 with respect to the neck portions of the preforms P. An opening / closing mechanism (not shown), a holding member 51 that holds the preform P, and an elevating cylinder 52 that elevates the opening / closing mechanism are provided. The opening / closing mechanism includes an air cylinder, a rod connected to the air cylinder, and a driven rod that is driven by a rod via a rack and pinion. Each gripping member 51 can be opened and closed with respect to the neck portion of each preform P by connecting the other of the gripping members 51 and driving the air cylinder.

  As shown in FIGS. 1 and 2, the blow molding station 6 is for molding a synthetic resin container by blow-molding the preform P transferred from the heating station 4, and each of the six preforms. Pallet-shaped blow conveyance member 61 that supports a molded product such as P in an inverted state, a blow conveyance path 60 that circulates and conveys the blow conveyance member 61 intermittently, and a primary blow along the blow conveyance path 60 A molding unit 7, a primary heat treatment unit 14, a secondary heat treatment unit 15, a final blow molding unit 9, and an extraction unit 10 are provided.

  As shown in FIG. 6, the blow conveyance member 61 is configured to hold six preforms P at a fixed pitch at the time of each process in each part.

  The blow conveyance path 60 has a substantially rectangular shape having a blow forward path 62 and a blow return path 65 for linearly conveying the blow conveyance member 61. As shown in FIG. 1, two rows of blow return paths 65 are arranged on both outer sides of the molding machine 1, and two rows of blow outward paths 62 are arranged on the inner side.

  The blow forward path 62 and the blow return path 65 include a blow forward path drive mechanism 64 and a blow return path drive mechanism 66 that move the blow transport member 61 to the next stop position, and a blow transport along the blow transport path 60. A blow forward guide rail 63 for guiding the member 61 and a blow backward guide rail 90 (see FIG. 6) are provided.

  The blow forward drive mechanism 64 includes a blow drive rod 73 in which a plurality of engagement plates 72 (see FIG. 6) protrude in one direction at predetermined intervals, a rotary actuator 74 that rotationally drives the blow drive rod 73, A ball screw (not shown) that moves the blow drive rod 73 and the rotation actuator 74 along the blow forward path 62, an electric servo motor 75 that rotationally drives the screw shaft of the ball screw, the blow drive rod 73, and the rotation A blow driving guide rail (not shown) for guiding the movement of the actuator 74 is provided.

  Then, by rotating the blow driving rod 73 by the rotation actuator 74 to bring the engagement plate 72 into contact with both ends in the longitudinal direction of the blow conveying member 61, and by rotating the screw shaft of the ball screw by the electric servo motor 75, The blow drive rod 73 and the rotary actuator 74 are moved along the blow forward path 62 while being guided by a blow drive guide rail (not shown), and the blow transport member 61 is moved by a predetermined distance via the engagement plate 72. ing.

  After the movement, the blow actuator rod 73 is rotated by the rotary actuator 74 to release the engagement between the engagement plate 72 and the blow conveying member 61, and the screw shaft of the ball screw is rotated in the reverse direction by the electric servo motor 75. Then, by returning the blow drive rod 73 by a predetermined distance, it is possible to prepare for the movement of the blow conveying member 61 in the next cycle. By repeating the operation of the blow forward drive mechanism 64, the blow transport member 61 can be moved in the transport direction A intermittently by a predetermined distance.

  Since the blow outward path drive mechanism 64 and the blow backward path drive mechanism 66 have basically the same configuration, the description thereof will be omitted. In the case of the blow backward path drive mechanism 66, the blow direction drive mechanism 66 blows in the direction opposite to the conveyance direction A. Since the conveying member 61 is moved, the rotation of the electric servo motor 75 is reversed from that of the blow forward drive mechanism 64.

  In addition, an outward path delivery mechanism 68 that delivers the blow transport member 61 from the blow return path 65 to the blow forward path 62 at the end of the blow forward path 62 and the blow return path 65 of the blow transport path 60, and a blow A return path delivery mechanism 69 that delivers the blow conveying member 61 from the forward path 62 to the blow return path 65 is provided.

  As shown in FIG. 6, the forward path delivery mechanism 68 positions and places the blow transport member 61 waiting at the terminal stop position 71, which is the end of the blow return path 65 on the heating station 4 side. And a horizontal movement mechanism 79 for reciprocally driving the mounting member 78 at the ends of the return path and the forward path 62 for blow. The mounting member 78 guides a part of the blow conveying member 61 on the side of the blow return path 65 and a positioning pin 80 which can be moved forward and backward to engage and position in two holes provided in the blow conveying member 61. A guide rail 81 is provided. The horizontal movement mechanism 79 includes a servo motor 82 and a ball screw mechanism 83, and can drive the mounting member 78 reciprocally by driving the servo motor 82 and rotating the screw shaft. During the horizontal movement, the positioning pin 80 rises and engages with the blow conveying member 61, so that it can be moved reliably. At the terminal stop position 71 of the blow return path 65, there are blow return path guide rails 90, 91, 92 along the blow return path 65. In particular, the blow return guide rail 92 on the blow return path 65 side can be moved up and down by an air cylinder (not shown) when the blow conveying member 61 is moved to the blow forward path 62. The mounting member 78 can be lowered when the blow conveying member 61 is conveyed to the receiving stop position 70 on the blow outward path 62 side. Similarly, a blow forward guide rail 63 on the blow return path 65 side can be moved up and down in the blow forward path 62.

  Since the return path delivery mechanism 69 is substantially the same mechanism as the forward path delivery mechanism 68, description thereof is omitted.

  At the end of the blow return path 65 where the return path delivery mechanism 69 is located, there is a take-out section 10 that reverses the synthetic resin container, which is the final molded product, from the inverted state to the upright state and takes it out of the molding machine.

  A primary blow molding part 7, a primary heat treatment part 14, a secondary heat treatment part 15 and a final blow molding part 9 are arranged in a straight line in the blow outward path 62.

  In FIG. 1, each molding part and each heat treatment part are shown by omitting an upper bottom lifting mechanism provided above each mold clamping mechanism in order to represent a state of the blow forward path 62. The primary blow molding section 7, the primary heat treatment section 14, and the final blow molding section 9 have a primary blow molding mold, a heat treatment mold, and a final blow mold that are split molds, and the mold clamping mechanisms 11, 12, 13 The mold is clamped and molded and heat treated.

  The primary blow molding part 7 biaxially stretch-blow-molds the preform P heated at the heating station 4 and at an appropriate stretching temperature in the primary blow mold to obtain a primary blow-molded product larger than the final molded product. The primary heat treatment unit 14 heats the primary blow-molded product by bringing it into contact with the inner surface of the heat treatment mold having substantially the same cavity as that of the primary blow mold while pressurizing the primary blow-molded product from inside. After the primary heat treatment is completed, the high-pressure air inside the primary blow-molded product is exhausted, the primary blow-molded product is shrunk, distortion is removed, and the primary heat treatment mold is opened to open a slightly smaller intermediate than the final molded product. A molded product is obtained. The secondary heat treatment section 15 has a secondary heat treatment box, and the intermediate molded product is heated in the secondary heat treatment box with almost no shrinkage. The final blow molding unit 9 blow-molds an intermediate molded product that has been subjected to secondary heat treatment in a final blow molding die heated to a desired heat-resistant temperature or more into a final molded product. The final molded product obtained is greatly reduced in distortion due to heat shrinkage after the primary heat treatment step, and the crystallinity is greatly increased by the heat treatment during the primary, secondary heat treatment and final blow molding, and preferable heat resistance. A synthetic resin container having

  Next, the operation of the molding machine 1 will be described with reference to the drawings.

  First, as shown in FIGS. 1 and 2, the upright preform P is supplied from the outside of the molding machine 1 to the supply unit 3. The temperature of the preform P at this time is usually about room temperature, but it may be preheated in advance.

  Next, as shown in FIG. 3, the six preforms P aligned in the supply unit 3 are turned upside down by the reverse delivery mechanism 18, and further, at the end of the heating forward path 20 a, the heating raising mechanism It is delivered to the holder 24 of the heating conveying member 21 supported by the 29 rising guide rails 30 and stopped. The heating conveyance member 21 supported by the ascending guide rail 30 and the heating conveyance member 21 arranged in the heating outward path 20a are divided into one heating conveyance member 21 in the conveyance direction A by the heating outward path driving means 26. Move by the width of. The heating conveying member 21 is conveyed and stopped on the lowering guide rail of the heating lowering mechanism 28 at the end of the heating outward path 20a while the preform P heated by the heating station 4 is supported.

  As shown in FIGS. 4 and 5, the heated six preforms P are gripped at the delivery position of the preform P with the gripping member 51 of the transfer unit 5 opened in advance, as shown in FIGS. 4 and 5. The mechanism 50 is disposed, the preform P is held by closing the gripping member 51 with respect to the neck portion, and the gripping member 51 is lifted by the elevating cylinder 52 and the preform P is removed from the holder 24 of the heating conveyance member 21. Pull out. Further, the rotation of the servo motor of the direction changing mechanism 53 rotates the arm 54 around the rotation shaft 55 as shown in FIG. 6, and the preforms P are arranged above the forward path delivery mechanism 68 of the blow conveyance path 60. Turn direction 90 degrees. The gripping member 51 is stopped on the blow conveying member 61 at the end of the blowing forward path 62, the gripping member 51 is lowered by the elevating cylinder 52, and the preform P is inserted into the holder 67 of the blowing transport member 61 and gripped. The member 51 is opened and the delivery of the preform P is completed. The gripping mechanism 50 turns the arm 54 in the reverse direction while keeping the gripping member 51 open, and waits for the next preform P at the end of the heating forward path 20a.

  Further, after the preform P is transferred to the transfer section 5, as shown in FIGS. 4 and 5, the heating transport member 21 is transported to the end of the heating return path 20b by the heating lowering mechanism 28, and is heated. The heating engagement pieces 35 fixed to the return path drive rod 33 engage with both ends, and are conveyed in the direction opposite to the conveyance direction A by the heating return path drive rod 33. The heating conveying member 21 conveyed for a predetermined distance is heated by the positioning rod 31 being rotated 90 degrees simultaneously with the release of the heating engagement piece 35 by rotating the heating return path driving rod 33 by 90 degrees. Positioning engagement pieces 32 fixed to the positioning rod 31 are engaged with both ends of the conveying member 21 for heating, and the conveying member 21 for heating is stopped.

  The heating conveyance member 21 is cooled in the heating return path 20b. The heating conveyance member 21 may be naturally cooled while being conveyed, or may be forcibly cooled by disposing a cooling fan (for example, an axial fan) below the heating return path 20b. By forcibly cooling, the time required to cool the heating transport member 21 in the heating return path 20b is shortened, and therefore the number of heating transport members 21 arranged in the heating return path 20b can be reduced. The cost of the equipment is reduced.

  As shown in FIGS. 1 and 2, the six preforms P delivered to the blow conveyance member 61 in the blow forward path 62 are intermittently conveyed by the blow forward drive mechanism 64 to perform primary blow molding. Infrared heater of the secondary heat treatment part 15 is formed by forming a primary blow molded product in the part 7, heat treating the primary blow molded product in the heat treatment mold in the primary heat treatment part 14, and shrinking simultaneously with the mold opening. Further heat treatment is performed, and blow molding is performed at the final blow molding unit 9 to obtain six final molded products. The final molded product is a heat-resistant synthetic resin container and is taken out of the molding machine from the take-out part 10.

  In this manner, the transfer unit 5 simplifies the structure of the heating station 4 by changing the alignment direction of the preforms P to be simultaneously blow-molded by 90 degrees, and the high-speed movement of the blow conveyance path 60 is also achieved. It becomes possible.

  The present invention is not limited to the above-described embodiment, and can be modified into various forms within the scope of the gist of the present invention.

  For example, in the above embodiment, the case where the heating station 4 and the blow molding station 6 are provided has been described. However, an injection molding station can be combined therewith, or only the blow molding station 6 can be used.

  Moreover, in the said embodiment, although the primary heat processing part 14 and the secondary heat processing part 15 were provided, you may put together to one heat processing part, or heat the primary blow metal mold | die of the primary blow molding part 7 and heat processing. Alternatively, the primary heat treatment unit 14 and the secondary heat treatment unit 15 may be omitted.

  Furthermore, in the said embodiment, although the direction change mechanism 53 is changing the arrangement direction of a 90 degree preform, it can be made into arbitrary angles according to a molding machine not only this but.

It is a top view which shows the whole structure of the molding machine of the heat resistant synthetic resin container using the blow molding machine which concerns on one embodiment of this invention. It is a side view of the molding machine of FIG. It is a side view of a heating station. It is a top view of a heating station. It is a front view of the heating station seen from the transfer part side. It is a top view of a transfer part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molding machine 2 Machine stand 3 Supply part 4 Heating station 5 Transfer part 6 Blow molding station 7 Primary blow molding part 9 Final blow molding part 10 Extraction part 14 Primary heat treatment part 15 Secondary heat treatment part 20a Heating path 20b Heating return path 21 Heating conveyance member 50 Grip mechanism 51 Grip member 53 Direction changing mechanism 54 Arm 55 Rotating shaft 60 Blow conveyance path 61 Blow conveyance member 62 Blow forward path 65 Blow return path 70 Receipt stop position 71 End stop position 79 Horizontal movement mechanism P Preform A Transport direction

Claims (2)

Simultaneously blow-molding a heating station for heating the preform, a transfer unit for transferring the heated preforms to the blow molding station N (N ≧ 2), and N preforms received from the transfer unit. In a blow molding machine having a blow molding station for molding N synthetic resin containers,
The heating station is
A heating forward path for conveying a plurality of heating conveying members arranged and supported by N preforms in a first direction along a second direction orthogonal to the first direction;
A heating return path provided below the heating outbound path and in parallel with the heating outbound path;
A lowering mechanism for lowering the heating transport member from the heating forward path toward the heating return path at one end of the heating outward path located on the transfer unit side;
A lifting mechanism that raises the heating transport member from the heating return path toward the heating outbound path at the other end of the heating outbound path;
Have
The heating return path conveys a number of heating conveyance members smaller than the number of the heating conveyance members arranged in the heating outbound path in a direction opposite to the second direction, and the heating return path A blow molding machine characterized by cooling or forcibly cooling a heating conveying member conveyed along the line. Received from a heating station for heating the preform on the machine base, two transfer units for transferring the heated preforms by N (N ≧ 2) to the blow molding station, and the two transfer units. In a blow molding machine having two blow molding stations for simultaneously molding each N number of preforms to form each N number of synthetic resin containers,
The two blow molding stations are
A plurality of blow conveying members that support and convey the N preforms received from the transfer unit;
Two rows of blow return paths provided along two sides on the machine base for returning and conveying the plurality of blow transport members;
A two-row blowing path provided in parallel with the two-row blowing path in the same horizontal plane as the two-row blowing path between the two-row blowing return paths on the machine base; ,
Including
Each of the two transfer units includes a gripping mechanism that grips N preforms arranged in the first direction, and a direction change that rearranges the N preforms in the second direction by turning the gripping mechanism. Including the mechanism,
The gripping mechanism has N sets of gripping members that grip the N preforms, and an elevating cylinder that lifts and lowers the N sets of gripping members,
The direction changing mechanism of each of the two transfer units has an arrangement position of each of the N preforms whose turning center positions are arranged between the two rows of blow outward paths and are rearranged by each of the direction changing mechanisms. Is coincident with each position on the two lines of blow outward paths.

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