JP3916167B2 - Injection stretch blow molding machine - Google Patents

Description

  The present invention relates to an injection stretch blow molding machine configured by arranging a stretch blow molding unit in a mold clamping device of a horizontal injection molding machine having a normal structure.

  Conventional injection molding of hollow molded products includes two molding methods, injection blow molding and injection stretch blow molding. Injection blow molding has a plurality of injection core molds that are alternately closed with both injection cavity molds and blow cavity molds, and preforms that have been injection molded around the injection core molds can be used as blow cavity molds together with the injection core molds. It is transferred and air blown from the injection core mold to the preform in the blow cavity mold to form a hollow molded product.

  As the preform transferring means, vertical rotating means, horizontal rotating means, etc. are adopted, and inclined rotating means for transferring the preform injection-molded in the horizontal position to the vertical position, etc. are adopted there. Due to the structure of the rotary transfer means, it is not possible to easily perform blow molding of a hollow molded product using a horizontal injection molding machine having a normal structure as it is, and therefore, an injection blow molding machine is provided as a dedicated machine.

  For stretch blow molding, two-station method (cold parison method) in which preform injection molding and stretch blow molding are performed on separate molding machines, and injection blow molding to preform blow molding as well as injection blow molding. There is a one-station method (hot parison method) that performs the above operation continuously.

  Even in the one-station system, the preform is held in the injection core mold and transferred to the blow cavity mold in the same manner as in the injection blow molding, and the preform is transferred into the blow cavity mold by the draw rod and the air blow charged in the injection core mold. , A method of stretch blow molding into hollow molded products, and pulling out the injection core mold, holding the neck or mouth of the preform by the neck mold (lip mold), transferring it to the blow cavity mold, and separately preparing the stretch rod interior There is a method in which a preform is stretch blow molded into a hollow molded product in a blow cavity mold using the above blow core.

  In the transfer and stretch blow of the preform by the injection core mold, the preform is stuck to the injection core mold, so that it is difficult to stretch in the axial direction by the stretch rod, and the temperature distribution is not affected by the thermal effect from the injection core mold side. Since uniform stretch blow is difficult due to stability, it has not been adopted as a practical machine at present, and even when transferring by an injection core mold, a method of extracting the injection core mold and replacing it with a blow core at the time of stretch blow is adopted. ing.

  For this reason, all of the one-station systems that have been put into practical use adopt a method in which the injection core mold is removed and replaced with a blow core with a stretch rod built in the blow position, thereby performing stretch blow. ing.

  However, injection stretch blow molding by core replacement requires an injection core mold loading / unloading device for the injection cavity mold and a blow core mold loading / unloading device for the blow cavity mold, and a rotating means is used to transfer the preform. Therefore, the structure is more complicated than that of an injection blow molding machine, and it is commercially available as an expensive dedicated machine.

  The present invention has been conceived in view of the above circumstances, and its object is to provide a stretch blow device, a rotational transfer means for an injection-molded preform, and an injection and blow device between a fixed plate and a movable plate of a mold clamping device. It is an object of the present invention to provide a new stretch blow molding machine that can easily perform a blow blow molding of a hollow molded product even with a horizontal injection apparatus having a normal structure by attaching a cavity mold as a unit.

According to the above-mentioned object, the present invention provides a clamping device for a horizontal injection molding machine, which is attached to a center of an inner surface of a front mold mounting plate, and a pair of mold mounting plates opposed to the front and rear of a central plate having a tie bar insertion hole at a corner. The injection cavity mold, the base block fixed on the front mold mounting plate side of the central plate and the front surface formed on a slope with an angle of 45 ° downward, the injection cavity mold and the base block mounted on both mold mounting plates A blow cavity mold with a split mold that can be freely opened and closed on the lower side, and a two-cavity mold with a vertical section that has two mold mounting surfaces facing both the injection cavity mold and the blow cavity mold at a right angle, with the center as the axis A neck-type transfer stand mounted on the blow cavity mold with the back surface held on the inclined front surface of the base block so as to rotate relative to the base block, a neck mold attached to the mold mounting surface of the transfer stand, and a rear mold The base end is fixed to the base plate and inserted into the base block and the transfer table, and the core member in which the injection core mold at the tip is positioned in the injection cavity mold through the neck mold, and the extension rod installed on the base block. A stretch blow molding unit comprising a stretch blow device in which a blow core with a built-in interior is provided so as to be movable up and down to a neck mold on a blow cavity mold, and a rotation drive device of a transfer table attached to a base block ,
A front mold mounting plate is mounted on the fixed plate side of the mold clamping device, and a rear mold mounting plate is mounted on the movable plate side, while the rotation transfer means and the stretch blow device are movable to a tie bar between the fixed plate and the movable plate. It is inserted and supported, and is provided so that the mold clamping of the injection cavity mold and the injection core mold and the mold clamping of the blow cavity mold can be performed simultaneously by the forward movement of the movable platen.

  In the above configuration, the horizontal injection molding machine is used as an injection stretch blow molding machine simply by disposing a stretch blow molding unit between a fixed plate and a movable plate provided in a mold clamping device of a horizontal injection molding machine having a normal structure. be able to. In addition, since both the injection and blow cavity molds can be clamped by moving the movable plate forward, the molding operation is not particularly different from that during normal injection molding, and it is limited to the wide-mouthed container of the hollow molded product to be molded. In addition, since ordinary bottles can be molded, the range of use of a general-purpose horizontal injection molding machine that is less expensive than a dedicated machine is increased.

  In the figure, 40 is an injection device of a horizontal injection molding machine, 41 is a mold clamping device, both of which are arranged horizontally on the machine base. The mold clamping device 41 is connected to fixed plates 42 and 42 'standing on the machine base, a movable plate 43 inserted and supported by a tie bar 44 connecting the fixed plates 42 and 42', and the movable plate 43. The stretched blow molding unit 1 is mounted between the fixed platen 42 and the movable platen 43 and has a normal configuration with a mold clamping ram 45 of a mold clamping cylinder (not shown).

  The stretch blow molding unit 1 includes a center plate 3 and a pair of mold mounting plates 2 and 3 provided in front and rear of the center plate 3, and the front mold mounting plate 2 and the central plate 3 have four corners in FIGS. As shown in FIG. 6, the insertion holes 5 and 6 of the tie bar 44 are formed.

  At the center of the inner surface of the front mold mounting plate 2, an injection cavity mold 7 for molding a preform is inserted through the sprue portion, and the front upper portion of the central plate 3 facing the front mold plate is 45 ° downward. A hollow base block 8 formed on an inclined surface of the angle is fixed. Under the base block 8 and the injection cavity mold 7, a pair of split molds 9a and 9b are attached to the rear mold mounting plate 4 through a recess 3a formed on the lower side of the front mold mounting plate 2 and the central plate. A blow cavity mold 9 is arranged.

On the blow cavity mold 9, there is provided a transfer table 10 which constitutes a rotary transfer means for the preform together with a rotation drive device 26 which will be described later. The transfer table 10 is a longitudinal cross-sectional hollow having two mold mounting surface facing both of the injection cavity mold 7 and the blow cavity mold 9 at right angles is from the base of the triangle shape, both cavity mold its center as the axis On the other hand, the back surface to which the pulley 11 is attached is rotatably held by a bearing on the inclined front surface of the base block 8 so as to be inclined and rotated.

  A core insertion hole 12 is formed in the center of the two mold mounting surfaces of the transfer table 10, and a neck that alternately faces both the injection cavity mold 7 and the blow cavity mold 9 outside the core insertion hole 12. Molds 13 and 13 are attached. The neck mold 13 has a normal structure that slides and opens sideways against the spring member that maintains the closed state, and the injection core mold 14 is inserted into the injection cavity mold 7 through the neck mold 13.

  The injection core mold 14 is integrally formed by fixing the base end to the inner surface of the rear mold mounting plate 4 and providing a step portion at the distal end of the core member 15 inserted into the base block 8 and the transfer table 10. The stepped portion is brought into contact with the periphery of the neck mold 13 so that the injection pressure at the time of preform molding can be received through the core member 15 on the center plate side. The core member 15 is provided with a vertical hole 16 located between the blow core insertion hole 8a above the base block and the core insertion hole 12 on the blow cavity mold 9, and this vertical hole 16 will be described later. The blow core 18 that penetrates passes through and the tip of the blow core 18 reaches the neck mold 13 on the blow cavity mold side from above the base block.

  Reference numeral 17 denotes a stretch blow device installed on the base block 8, and a guide column 19 provided on both sides of the upper portion of the base block 8 and a rear end of the blow core 18 whose tip is housed in the insertion hole 8 a are attached. The piston rod 22 is connected to the lifting member 20 by holding 18 downwardly at the front lower side and standing on the lifting member 20 inserted through the guide column 19 on both sides of the rear and the seat plate 21 provided across the guide column 19. An air or hydraulically operated lifting cylinder 23 and an air or hydraulically operated stretching cylinder 25 standing on the front part of the lifting member 20 and connecting a piston rod 24 to a stretching rod 25 in the blow core 18.

  Reference numeral 26 denotes a rotation driving device for the transfer table 10, which is attached to the side of the central plate 3 and is provided on the side of the base block 8 opposite to the operation side at a 45 ° angle in parallel with the front surface of the base block 8. 27, an electric servo motor 28 installed on the upper surface thereof, an intermediate pulley 29 supported on the lower surface of the support plate 27, a pulley 30 at the tip of the motor shaft, and the pulleys 29, 30 and the pulley 11 of the transfer table 10 are wound around. And a driving timing belt 31.

  Reference numeral 32 denotes a mold opening member of the neck mold 13, which is fixed to the inner side of the center plate 3 and attached to the front end portions of holders 33 provided on both sides of the blow cavity mold 9 as shown in FIG. 6. The opening / closing member 32 is connected to a piston of an air or hydraulic cylinder 34 and is formed of a wedge-shaped member having a tip facing a side portion of the parting line of the neck mold 13.

  An open / close rod 35 is provided at the opposite corner of the front mold mounting plate 2 and the central plate 3. The front end is connected to the central plate 3, the rear end is inserted into the front mold mounting plate 2, and the rear end is mounted on the front mold. Connected to the hydraulic cylinder 6 attached to the outside of the plate 2 and provided so as to be able to advance and retreat over both plates, whereby the central plate 3 is associated with the front die mounting plate 2 so as to be able to advance and retract, and is suitable for a horizontal injection molding machine. The stretch blow molding unit 1 is configured.

  In the illustrated stretch blow molding unit 1, the open / close rod 35 is disposed across the front mold mounting plate 2 and the central plate 3, but the open / close rod 35 is omitted in the drawing, but the central plate 3 and the rear mold are omitted. In this case, the hydraulic cylinder 36 is attached to the rear mold mounting plate 4, and the mold is closed by the forward movement of the central plate 2 by extension of the opening / closing rod 35. The mold can be opened by retreating by reduction.

  As shown in FIG. 4, the stretch blow molding unit 1 having the above-described configuration is attached to the mold clamping device by first placing the stretch blow molding unit 1 between the fixed platen 42 and the movable platen 43 before the tie bar 44 is inserted. In the closed state, the front mold mounting plate 2 is suspended toward the fixed platen side. Next, the tie bars 44 and 44 are inserted into the four corners of the fixed platen 42 and 42 ′, the movable platen 43, the front mold attaching plate 2 and the central plate 3, and the fixed plates 42 and 42 ′ are connected. As a result, the transfer table 10, the rotation drive device 26 and the stretch blow device 17 are supported by the tie bars 44, 44 through the central plate 3 so as to be movable. Thereafter, the front mold mounting plate 2 is pinned inside the fixed platen 42 and the rear mold mounting plate 4 is pinned inside the movable platen 43.

  By this pinning, the die mounting plate 4 is integrated with the movable platen 43, and the movable platen 43 is moved forward and backward to open / close and mold the blow cavity die 9, and the injection cavity die 7 and the injection core die 14 on the fixed platen side. This is a horizontal injection stretch blow molding machine capable of simultaneously opening and closing the mold and clamping the mold.

  In the above configuration, the front mold mounting plate 2 is inserted through the tie bar 44 at the four corners together with the central plate 3, but the front mold mounting plate 2 does not necessarily need to be inserted and supported by the tie bar 44. 5 may be omitted and the front mold mounting plate 2 may be simply pinned to the fixed platen 41.

  In the injection stretch blow molding machine having the above-described configuration, when the open / close rod 35 is reduced by the hydraulic operation of the open / close cylinder 36 in the mold open state shown in FIGS. 1 and 2, the center plate 3 is moved together with the base block 8 to the fixed platen 42 side. As a result of the drawing, the injection cavity mold 7 of the front mold mounting plate 2 and the neck mold 13 on the vertical surface of the transfer table 10 are closed. Further, the neck 13 in the horizontal plane is drawn toward the split mold 9b on the front mold mounting plate 2 side of the blow cavity mold 9, and the half mold is closed.

  Next, when the mold clamping cylinder (not shown) of the mold clamping device 41 is hydraulically operated, the mold clamping ram 45 is extended and the movable platen 43 is moved forward, and the movable platen 43 and the rear mold attachment plate 4 are blown together. One split mold 9 a of the cavity mold 9, the core member 15 and the opening / closing member 32 move forward, and the injection core mold 14 at the tip of the core member penetrates the neck mold 13 from the core insertion hole 12 and the injection cavity mold 7. A wide-mouth preform injection cavity is formed around the injection core mold 14.

  At this time, the step at the tip of the core member 15 is in contact with the neck mold 13 and presses the neck mold 13 against the injection cavity mold 7. On the blow cavity mold 9 side, the split mold 9a is closed with the split mold 9b on the front mold mounting plate 2 side with the neck mold 13 holding the preform interposed therebetween, thereby forming a blow cavity of the wide-mouth container. Then, the mold is clamped by further pressurization of the plunger, and the state is maintained (see FIG. 3).

  After the mold clamping, when a molten resin is injected and filled into the injection cavity mold 7 from the injection device 40 that is nozzle-touched to the sprue, a preform is injection molded around the injection core mold 14. At this time, the injection pressure is received by the core member 15 pressed by the movable platen 43 by the stepped portion in contact with the neck mold 13, so that the injection pressure is not applied to the transfer table 10, and the holding force by the base block 8 is applied. There is no burden.

  At the same time, in the blow cavity mold 9 that has been clamped, stretch blow is performed to mold the preform that has been rotated and held by the neck mold 13 into a wide-mouth container. This stretching blow is performed by continuous operation of the elevating cylinder 23 and the stretching cylinder 25 of the stretching blow apparatus 17 after completion of mold clamping.

  First, as shown in FIG. 3, the tip of the blow core 18 accommodated in the insertion hole 8 a by the operation of the elevating cylinder 23 passes through the vertical hole 16 of the core member 15 and enters the blow cavity mold 9 and the neck mold 13 closed with the mold. The elevating member 20 is lowered to a position where it is inserted. Next, the stretching cylinder 26 is operated to extend the stretching rod 25, and at the same time, compressed air is pumped into the blow core from an air passage (not shown) to stretch and blow the preform. As a result, the preform is stretched and expanded to fill the blow cavity to form a wide-mouthed container. This stretch blow molding can be performed simultaneously with the injection molding or during the injection molding.

  After the molding is completed, the mold opening precedes the pulling-up operation of the blow core 18 and the stretch rod 25 in the stretch blow apparatus 17, and then the injection cavity mold 7, the neck mold 13 and the injection core mold 14, the neck mold 13 and the blow cavity mold. 9 is opened by the backward movement of the movable platen 43. When the movable platen 43 moves backward due to the reduction of the mold clamping ram 45, the core member 15 also moves backward together with one split mold 9a of the blow cavity mold 9, and the injection core mold 14 is pulled out from the injection cavity mold 7 and split. The mold 9a is separated from the other divided mold 9 on the fixed platen 2 side, and the blow cavity mold 9 is opened.

  As the movable platen 43 moves backward, a mold opening space is generated between the central plate 3 and the movable platen 43, and the neck die 13 is not restrained by the pressing of the core member 15. When the opening / closing rod 35 is extended by the hydraulic cylinder 36 in parallel with the backward movement, the central plate 3 moves backward together with the base block 8 and the transfer table 10, and the injection cavity mold 7 and the neck mold 13 are opened, and the neck The mouth is held by the mold 13 and the preform is released from the cavity.

  In the blow cavity mold 9, the neck mold 13 is separated from the split mold 9 b on the front mold mounting plate 2 side and completely released by the backward movement of the base block 8 and the transfer table 10 while holding the wide-mouth container.

  The mold opening by the retraction of the movable platen 43 is performed until the injection core mold 14 fits in the base block 8 in FIGS. 1 and 2, but the injection core mold 14 does not interfere with the rotation of the transfer table 10. The mold opening members 32 on both sides of the blow cavity mold 9 are pushed into the parting surface of the neck mold 13 at the mold opening completion position to open the mold, and the wide-mouth container is released.

  When the wide-mouth container is released from the mold, the preform is rotated and transferred to the blow cavity mold 9. This transfer is performed by rotating the electric servo motor 28 by 180 °. The rotation by the electric servo motor 28 is transmitted to the transfer table 10 by the timing belt 11, and the mold mounting surface changes from vertical to horizontal by the tilt rotation of the transfer table 10, and the preform held on the neck mold 13 is blow cavity The neck mold 13 is positioned on the parting side of the injection cavity mold 7 downward and on the opposite side of the injection cavity mold 7 after the wide-mouth container is released from the blow cavity mold 9.

  When the transfer by the tilting rotation of the transfer table 10 is completed, the molds of the injection cavity mold 7 and the neck mold 13 are closed by the reduction of the opening / closing rod 35 in the mold opening position shown in FIGS. 1 and 2 again. The mold is clamped between the injection core mold 14 by the forward movement of the movable plate 43 and the injection cavity mold 7 and the neck mold 13, and the neck mold 13 holding the preform and the blow cavity mold 9 are clamped at the same time. It moves to the next injection stretch blow process.

  As described above, in the stretch blow molding machine having the above-described configuration, the mold clamping device of the horizontal injection molding machine having the normal structure can be used as it is, and the mold clamping of both the injection and blow cavities can be performed simultaneously by the forward movement of the movable platen. Therefore, injection stretch blow molding can be performed by a molding operation similar to that of normal injection molding, and the present invention is not limited to a wide-mouth container of a hollow molded product to be molded, and a normal bottle can also be molded. Further, when stretch blow molding is not required, the unit can be used as it is as a normal injection molding machine by replacing the unit with an injection cavity mold of another molded product.

It is a vertical side view at the time of mold opening of the mold clamping apparatus in the injection stretch blow molding machine of this invention. It is a top view same as the above. It is a vertical side view of the mold clamping device when the mold is closed. It is a side view of the mold clamping apparatus at the time of attachment of a stretch blow molding unit. It is a side view in the mold closed state of the stretch blow molding unit. It is a front view except a front part mounting plate same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stretch blow molding unit 2 Front mold attachment plate 3 Center plate 4 Rear mold attachment plate 5,6 Tie bar insertion hole 7 Injection cavity mold 8 Base block 9 Blow cavity mold 10 Transfer base 11 Transfer base pulley 13 Neck mold 14 Injection core mold 15 Core member 17 Stretch blow device 18 Blow core 25 Stretch rod 27 Support plate 28 Electric servo motors 29, 30 Pulley 31 Timing belt 40 Injection device 41 Mold clamping device 42 Fixed platen 43 Movable platen 44 Tie bar 45 Mold clamping ram

Claims (1)

In the mold clamping device of the horizontal injection molding machine, a pair of mold mounting plates facing the front and rear of the center plate having a tie bar insertion hole at the corner, an injection cavity mold mounted at the center of the inner surface of the front mold mounting plate , A base block that is fixed to the front mold mounting plate side of the plate and has a front face formed on a slope with an angle of 45 ° downward, and can be attached to both mold mounting plates so that it can be opened and closed to the lower side of the injection cavity mold and the base block. A vertical section with a right angle of two mold mounting faces facing both the injection cavity mold and the blow cavity mold with the split mold arranged so that it is inclined with respect to both cavity molds around the center , Neck-type transfer stand provided on the blow cavity mold with the back surface held on the inclined front face of the base block, the neck type attached to the mold mounting surface of the transfer stand, and the base end fixed to the rear mold mounting plate Then Inserted into the block and transfer stand, the core member with the injection core mold at the tip located in the injection cavity mold through the neck mold, and the blow core with the stretching rod installed on the base block and placed on the blow cavity mold A stretch blow molding unit composed of a stretch blow device provided so as to be movable up and down to a neck type and a rotation drive device of a transfer table attached to the base block ,
A front mold mounting plate is mounted on the fixed plate side of the mold clamping device, and a rear mold mounting plate is mounted on the movable plate side, while the rotation transfer means and the stretch blow device are movable to a tie bar between the fixed plate and the movable plate. An injection stretch blow molding machine characterized in that it is inserted and supported so that the mold can be clamped simultaneously between the injection cavity mold and the injection core mold and the blow cavity mold can be clamped simultaneously by the forward movement of the movable platen. .

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