JP2007098662A - Mold unit comprising neck mold and core mould - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To injection-mold the neck part of a preform with a neck mold which is cooled even in injection blow molding by fitting a core mold to the lower surface of a transfer board rotated by a mold unit formed by combining the neck mold and the core mold. <P>SOLUTION: The neck molds by a split mold are fitted to both openable/closable mold mounting plates on the lower surface of a base plate. The core body of the core mold is engaged with the neck mold, and a core member on the lower surface of the core body is made to penetrate the bottom part of the neck mold and projected downward to be long. A valve rod is set movably in an air passage bored from the upper end surface of the core body to the tip surface of the core member in the core mold. The core body is engaged with a hole part formed in the plate surface of the base plate, and the upper end part is projected on the base plate. The base plate is fitted to the lower surface of the opening of the transfer board, and the upper end part is housed in the opening. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a die unit for injection blow molding in which a neck mold for molding a neck part of a preform and a core mold for molding a body part and a bottom part are combined.

  In injection blow molding, a preform is injection-molded around the core mold of the injection mold, the preform is released together with the core mold at a high temperature and transferred to the blow mold, and the core mold is transferred to the preform in the blow cavity. High-pressure air is blown from the inside to form a hollow molded product such as a bottle.

  In the injection stretch blow molding, a core mold core is inserted into the cavity of the injection mold through a neck that can be opened and closed attached to the rotary transfer means side, and a preform is injection molded around the core. After that, the preform is released from both the core and the cavity at a high temperature, the neck portion is held by the neck mold, transferred to the blow mold in a hollow state together with the neck mold, and then transformed into the preform in the blow cavity. A stretch rod is inserted through the neck mold, and the preform is stretched in the axial direction by the stretch rod, and an air blow is performed from the neck portion to form a bottle with a barrel thinner than the injection blow molded product. Yes.

Moreover, as a cooling means for the injection-molded preform, a core fixing plate and a neck type presser plate stacked on the lower side of the core presser plate, and a lower surface of the neck type presser plate are elastically pressed by a spring member so as to be freely opened and closed. A pair of mold mounting plates, a cavity neck mold with a split mold mounted on both of the mold mounting plates, and the base end of the cavity neck are fitted to the base end, and the core pin at the center of the bottom of the base end is extended from the bottom of the neck mold A mold unit is configured from the projecting injection core mold, and the preform around the core pin held by the cavity neck mold and the injection core mold is cooled by the coolant circulating through the cavity neck mold and the injection core mold. It is known to transport to a cooling / removal station.
Japanese Patent Publication No. 50-9015 Japanese Patent No. 2832263 Japanese Patent No. 2902119

  In normal injection blow molding, a cavity of an injection mold is formed by a core mold and a cooled cavity mold, and molten resin is injected and filled into the cavity to form a bottomed preform. The preform is released from the cavity mold while being attached to the core of the core mold and is transferred to the split blow mold. After the mold is clamped, the preform is expanded by the air blown into the preform from the air passage in the core. Etc. are formed into hollow products. If both the cavity mold and blow mold of the injection mold are split in such an injection blow molding, the mold parting line is generated twice in the body of the hollow product due to the second clamping. Because it affects the appearance and labeling, a single cavity mold that can insert and remove the core of the core mold is often adopted as the injection mold.

  In this single cavity mold, the core is inserted and removed to open and close the mold, so when forming bottles with screws around the outer periphery of the neck, the split neck mold can be opened and closed on both sides of the core. The preform is molded during injection molding of the preform, or a screw or the like is molded on the outer periphery of the neck portion of the preform during blow molding. The neck portion formed at the time of blow molding is considered to be inferior in the neck portion molding accuracy, particularly the screw accuracy, as compared with the case of injection molding with a neck mold.

  In injection blow molding, a high temperature preform is attached to the core and transferred to the blow mold, so cooling the core mold lowers the preform temperature during transfer. Absent. For this reason, when the neck portion is formed at the time of injection molding, it is necessary to cool the neck die separately from the cavity die and solidify the neck portion.

  In injection blow molding, a core-type core provided with an air passage is commonly used as a blow mold blow core, and the air passage is inevitably always connected to an air supply path of a fixed supply device. For this reason, the core mold is provided so as to reciprocate or move laterally between the injection mold and the blow mold. As a means for reciprocatingly rotating the core mold, a plurality of core molds are horizontally mounted around an upright rotating shaft, and air is distributed and supplied from an air supply path in the rotating shaft to an air passage drilled in the core. Like to do. Further, since the air supply path on the rotating shaft side is connected to the supply device by a high-pressure hose, the reciprocating rotation of the core type is limited to within 180 ° from the twist prevention of the high-pressure hose. For this reason, an air supply path that does not become a rotation obstacle in order to intermittently rotate the core mold in one direction and continuously perform the process from the injection molding of the preform to the removal of the hollow product for each stop position. Connection is required. The neck type cooling means has a similar problem.

  In the injection stretch blow molding, the neck mold is intermittently rotated to continuously perform from the injection molding of the preform to the removal of the hollow product. This is because the core of the injection mold and the blow core of the blow mold move separately but do not move, and the preform is transferred by the neck mold. Since the core type and the blow core that only move up and down are always in a fixed position, the connection between the core type or blow core and the refrigerant or air supply device can be made watertight or airtight, and there is no rotational movement, so no twisting occurs. However, it is not possible to form a hollow product in which the precision of the neck portion is improved by adopting an injection stretch blow molding system for injection blow molding in which the preform is attached to the core and moves together with the core mold.

  It is also considered to use a gasket for the air supply path connection and a swivel joint for the cooling supply path connection to prevent twisting of the connection part due to rotation, but the swivel joint is a problem in long-term use. Are likely to occur and the maintenance period is short, which makes it difficult to adopt. As a means of cooling the preform, it may be possible to cool the neck mold by providing a cooling function to the neck and core mold units, but it is difficult to cool only the neck mold and the core is also cooled. Therefore, there is a problem that the preform is cooled by the core during transfer and blow molding becomes difficult.

  In the present invention, a core mold is attached to the lower surface of a rotating transfer board as in injection stretch blow molding even in injection blow molding, and preform injection molding, blow molding, and product removal can be continuously performed at different positions. Another object of the present invention is to provide a new neck mold and core mold unit that can be formed at the time of injection molding by a cooled neck mold for forming a neck portion of a preform.

  The present invention according to the above object includes a pair of mold mounting plates attached to the lower surface of the base plate so as to be openable and closable, a mold closing spring member that constantly presses the mold mounting plate inward, and both mold mounting plates. From the center of the bottom surface of the core base fitted into the neck mold, the neck mold from the perforated mold opening taper hole and the split mold that is attached to both the mold mounting plate and provided under the base plate An air passage formed in the core mold from the upper end surface of the core base to the front end surface of the core, and the air In a mold unit that is movably inserted into the passage and is provided with a valve rod that always closes the front end opening of the air passage by a spring member at the top of the passage, a hole in which the core base of the core die is provided on the plate surface of the base plate And the upper end protrudes above the base plate and The plate is fixed to the lower surface of the opening of the transfer board, the upper end is accommodated in the opening, and both the cooling means and the air blowing means can be contacted to the upper end. .

  The core base has a recess in the upper portion of the internal air passage that allows the insertion of a pressing pin protruding from the contact head of the air blowing means, and the upper portion of the valve stem is elastically pressed by the spring member in the recess. It is configured so that the front end opening of the air passage is opened by the pressing force of the pressing pin.

  Further, the base plate has a receiving member for the mold mounting plate on both sides of the lower surface in the mold opening / closing direction, and the receiving member is supported by elastically supporting the hanging pin upward through a suspension pin screwed through the base plate. With the spring member in the upper part of the base plate, together with the mold opening / closing plate fitted to the receiving material, the base plate is pulled to and from the lower surface of the base plate, and when the suspension pin is pressed, it is separated from the base plate against the spring member. It is made up of.

  In the above configuration, the core mold is separate from the cooling means and the air blowing means, and the cooling means and the air blowing means pressed against the upper end portion on the base plate can be moved away from the upper end portion so that the core mold can be rotated. In addition, the air blow means is not affected by the rotational movement of the mold unit, and injection blow molding by rotational transfer of the core mold is possible without using a swivel joint. Further, since the neck portion of the preform that becomes the neck portion of the hollow product can be injection-molded by the neck mold, the molding accuracy of the neck portion is improved and the sealing of the mouth portion by the cap is also improved.

  In the figure, reference numeral 1 is a mold unit in which the neck mold 2 and the core mold 3 are combined, and 4 is a rotatable transfer board on the lower surface of the support board 5. The mold unit 1 includes a pair of divided plate mounting plates 8 and 8 fitted on and attached to receiving members 7 and 7 on both sides of the lower surface of the base plate 6 so as to be openable and closable. , 8 are stretched around both ends of the guide pins 9, 9 inserted on both sides, and the mold mounting plates 8, 8 are always inwardly pressed inward, and the mold closing spring members 10, 10, and both mold mounting plates 8 , 8 and the pair of left and right mold opening taper holes 11, 11, and the above-mentioned neck mold by a pair of split molds 2 a, 2 a provided on both of the mold mounting plates 8, 8 and provided below the base plate 6 2 and a core mold 3 having a core 3b protruding from the center of the bottom surface of the cylindrical block-shaped core base 3a. The core base 3a is fitted into the neck mold 2 so that the core 3b is a party of the neck bottom 2a. It is long and protrudes downward through the mold hole 2b of the lip surface.

  Inside the core mold 3, it is movably inserted into the air passage 12 drilled in the tip surface of the core 3b from the upper end surface of the core base portion 3a, and the tip opening of the air passage 12 is always opened by the spring member 13 above the passage. A valve stem 14 is provided. The upper portion of the air passage of the core base portion 3a is formed in a recess 15 that allows insertion of a pressing pin 27a protruding from a contact head 27 of an air blowing means 26 described later (see FIG. 6). The upper part of the rod 14 is protruding. The upper end of the valve stem is a screw shaft with a washer attached. The valve rod 14 is elastically pressed by the spring member 13 stretched between the washer and the bottom surface of the recess to keep the valve closed. The core mold 3 is fitted into a hole 6a having a step portion provided on the plate surface of the base plate 6 at the upper portion of the core base portion 3a, and an upper end portion having a flat upper surface protrudes on the base plate.

  As shown in FIG. 4, suspension pins 16, 16 whose upper portions are located in the perforations of the transfer board 4 are screwed through the base plate 6 to the receiving members 7, 7 of the base plate 6. Further, a guide pin 17 passes through the base plate 6 in parallel with the suspension pin 16 and is inserted from the transfer board 4. Around the upper portion of the suspension pin 16, a spring member 18 that elastically supports the pin upward is stretched between the bottom surface of the recess formed in the base plate 6. The receiving members 7, 7 are pulled by the spring member 18 together with the mold opening / closing plates 8, 8 fitted therein to the lower surface of the base plate 6, and resist the spring member 18 by pressing the suspension pin 16. The mold opening / closing plates 8 and 8 are separated from the base plate 6 so that the neck mold 2 moves along the core 3b.

  The mold unit 1 having the above configuration is attached to the lower surface of the transfer plate 4 by fixing the base plate 6 to the lower surface of the opening 4 a provided in the transfer plate 4. With this attachment, the upper end portion of the core 3a is accommodated in the opening 4a, and both the cooling means and the air blowing means, which will be described later, are brought into contact with the flat upper end surface from the opening portion 5a of the support board 5, respectively.

  Although not shown in the drawing, the mold unit 1 is intermittently rotated together with the transfer plate 4 on the lower surface of the support plate 5 through an injection molding station, a blow molding station, and a product take-out station set on the machine base.

  As shown in FIG. 5, an injection mold apparatus 18 is installed on the machine base of the injection molding station, and a cooling means 19 is provided on the support board 5 as a mold clamping plate of a mold clamping apparatus (not shown). It is installed and can be moved up and down. As shown in FIG. 6, a blow mold 25 is installed at the blow molding station, and an air blow means 26 is mounted on a mold clamping plate of a mold clamping device (not shown) on the support plate 5 so as to move up and down. It is installed in. Further, as shown in FIG. 7, a mold opening means 28 of the neck mold 2 is installed on the support board 5 in the product take-out station.

  In the injection molding station, the mold unit 1 and the cavity mold 20 are closed and clamped after the transfer board 4 is stopped. This mold closing is performed by lowering the mold unit 1 to the cavity mold 20 together with the support board 5 and the transfer board 4 in the case of a molding machine in which the support board 5 is provided so as to be movable up and down on the machine base. Further, in a molding machine in which the support plate 5 is fixed and the injection mold device 18 is provided so as to be movable up and down, the injection mold device 18 is raised to close the mold.

  As shown in FIG. 5, the mold closing is performed by moving the bottom surface of the mold mounting plate 8 and the upper surface of the cavity mold 20 that is always cooled to a position where the neck mold 2 is fitted to the cavity opening. In this process, the core 3b enters the center of the cavity, and a preform cavity 21 connected to the inside of the mold cavity 2b is formed around the core.

  After closing the mold, the cooling head 22 of the cooling means 19 is lowered, and the lower end surface thereof is pressed from the opening 5a of the support plate 5 to the upper end surface of the core 3b of the opening 4a of the transfer plate 4, and the cavity mold 20 And the mold unit 1 is clamped. Due to this pressure contact, the cooling head 22 is cooled by the refrigerant flowing through the cooling path 23 therein, so that the core 3b is cooled. Since each member around the core 3b is also cooled by this cooling, the cooling of the core 3b far from the upper end surface to which the cooling head 22 is pressed is extremely small. The neck mold 3 receives cooling from both the cavity mold 20 and the core 3b.

  When the cooling head 22 is pressed and clamped, the molten resin is injected into the cavity 21 from the injection nozzle 24 at the bottom of the cavity mold 20, and the body and bottom except for the neck are the same as the cavity 21. Forming a preform with a shape. A screw is formed from the neck mold 2 on the outer periphery of the neck portion. When the injection cooling is completed, the preform P is released by mold opening. This mold release is performed while the temperature of the preform P is in a soft state where air blow is possible. However, the neck portion is solidified by cooling from the core base portion 3 a and the neck mold 2.

  The mold opening is performed by returning the mold unit 1 and the cavity mold 20 to the original positions by raising the support plate 5 or lowering the cavity mold apparatus 18. The reform P comes out of the cavity in the state of being hugged by the core 3b. The preform after mold release is transferred to the blow molding station together with the mold unit 1 by the rotation of the transfer board 4.

  In the blow molding station, as shown in FIG. 6, the mold unit 1 and the blow mold 25 are closed after the transfer 24 is stopped. This mold closing is performed when the blow mold 25 consisting of a pair of divided molds 25a, 25a and a bottom mold 25b is opened, as well as in the case of the injection molding station, together with the support plate 5 and the transfer plate 4 as a mold unit. 1 is lowered to the blow mold 25, or the blow mold 25 is raised, and the preform P around the core is positioned at the center of the blow mold 25, and then the blow mold 25 is clamped by a mold clamping device (not shown). Is closed to close the mold with the neck mold 2.

  When the mold is closed and the mold is clamped, the air blowing means 26 installed on the support board 5 is lowered to a position where it comes into contact with the support board, and the contact head 27 at the tip of the air blow means 26 is transferred from the opening 5a of the support board 5 to the transfer board 4. The upper end surface of the core base 3a of the opening 4a is abutted. On the lower end surface of the contact head 27, a pressing pin 27 a protrudes from the central air outlet, and the pressing pin 27 a is inserted into the recess 15 of the core base 3 a to press the upper end of the valve stem 14. As a result, the valve stem 14 is pushed down, and the valve body at the tip projects from the core 3b to the bottom mold 25b to open the air passage 12. Simultaneously with the opening of the valve, blow air flows into the air passage 12 from the contact head 27 and is press-fitted into the preform from the tip of the core 3b. Thus, the preform P expands to fill the cavity and is blow-molded into a bottle B having the same shape as the cavity and having a screw on the outer periphery of the neck portion.

  When the bottle B is formed, the air blowing means 26 is first raised and the contact head 27 is removed from the valve stem 14. The valve stem 14 is returned to the original position by the spring member 13 to close the air passage 11. Next, after the blow mold 25 is opened and the bottle B is released from the blow cavity 25, the mold unit 1 and the cavity mold 20 are returned to their original positions by ascending or descending. At this time, the bottle B is separated from the core 3 b by air blow, but the bottle neck portion is held by the neck mold 2, so that the bottle B is positioned above the blow mold 25 together with the mold unit 1. The released bottle B is transferred to the product take-out station together with the mold unit 1 by the rotation of the transfer board 4.

  As shown in FIG. 7, the mold opening means of the neck mold 2 installed on the support board 5 of the product take-out station includes a pair of support columns 29 and 29 on the support panel, and an air cylinder 30 provided downward on the top of the support column. The operation plate 32 that can be moved up and down is inserted through the support columns 29 and 29 and connected to the biston rod 31, and the opening and closing that is long attached to both sides of the operation plate 32 and inserted into the wedge holes on the plate surface of the support plate 5. Wedge members 33, 33, a pair of air-operated lifting cylinders 34, 34 installed on a support plate outside both columns 29, 29, an operation plate 36 attached to both piston rods 35, 35, and operation It is attached to the both sides of the plate long and downward, and includes push-down rods 37 and 37 inserted into the perforations on the surface of the support plate 5.

  In this product take-out station, as shown in FIG. 8, the elevating cylinders 34 and 34 are first lowered to push down the suspension pin 16 against the spring member 18 by the push-down rods 37 and 37. Since the lower end portion of the suspension pin 16 is connected to the receiving material 7 in which the die mounting plate 8 of the neck die 2 is fitted, the neck die 2 holding the neck portion of the bottle B together with the receiving material 7 is pushed down. To be separated from the base plate 6. As a result, the neck portion is also pushed down along the core 3b and is cut off from the core 3b.

  Next, the air cylinder 30 is lowered to push down the wedge members 34, 34. The front ends of both wedge members enter the taper holes 11 of the die attachment plate 8 from the wedge holes and are closed. Push 8 to the side. As a result, the neck mold 2 is opened left and right. At this time, since the core 3b is present in the bottle, the bottle B falls away from the neck mold 2 and can be taken out from the mold unit 1 by opening the neck mold 2. When the product removal is completed, the mold opening means 28 is restored, the neck mold 2 is closed and pulled to the base plate 6, and is circulated and transferred to the injection molding station together with the transfer board 4.

  As described above, even in the injection blow molding in which the preform is moved together with the core mold, by adopting the mold unit of the present invention, the core mold is rotated and moved in the same manner as the injection stretch blow molding, so that the injection molding of the preform is performed. Blow molding and product removal can be performed continuously at different positions. Further, since the neck portion can be formed by the cooled neck mold, the forming accuracy of the bottle neck portion is improved.

Although not shown in the figure, if the length of the preform is shorter than the depth of the cavity of the blow mold and the protruding stroke of the valve stem is set to a length that allows the tip to reach the bottom die, the valve body at the tip will open. Since the preform is extended to the bottom mold after the valve is formed, the preform can be stretched in the axial direction by the protruding stroke even in the injection blow molding.
Needless to say, the mold unit 1 of the neck mold 2 and the core mold 3 of the present invention can also be used for injection blow molding in which the core mold is reciprocated.

It is a center longitudinal section front view of a neck type and a core type metallic mold unit concerning this invention. It is a plane sectional view same as the above. It is a center vertical side view similarly. It is a vertical side view of the receiving part of the mold unit. It is a vertical side view in an injection molding station. It is a vertical side view in a blow molding station. It is a vertical front view in a product extraction station. It is a vertical side view of the receiving material part at the time of pressing down the neck type | mold in a product extraction station. It is a vertical side view of the receiving material portion when the neck type mold is similarly opened.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold unit 2 Neck type 3 Core type 3a Core base 3b Core 4 Transfer board 5 Support board 6 Base plate 7 Receiving material 8 Mold attachment plate 10 Opening / closing spring member 12 Air passage 13 Valve rod spring member 14 Valve rod 15 Recess 16 at the upper part of the air passage 18 Suspension pin 18 Injection mold unit 19 Cooling means 20 Cavity mold 21 Cavity 22 Cooling head 25 Blow mold 26 Air blow means 27 Contact head 27a Pressing pin 28 Mold opening means

Claims (3)

A pair of mold mounting plates attached to the lower surface of the base plate so as to be openable and closable, a mold closing spring member that constantly presses the mold mounting plate inwardly, and a mold opening for drilling across both mold mounting plates. From the center of the bottom surface of the core base that fits into both the taper hole and its mold mounting plate, and is provided under the base plate, and through the mold hole at the bottom of the neck mold. And a core type with a core projecting long downward,
Inside the core mold, an air passage drilled from the upper end surface of the core base to the tip surface of the core, and movably inserted into the air passage, the tip opening of the air passage is always closed by a spring member at the top of the passage. In a mold unit with a valve stem,
The core base of the core type is fitted into a hole provided in the plate surface of the base plate, the upper end protrudes above the base plate, and the base plate is fixed to the lower surface of the opening of the transfer plate, A neck type and core type mold unit, wherein the upper end portion is accommodated in the upper end portion, and both the cooling means and the air blowing means can be brought into contact with the upper end portion.   The core base has a recess in the upper part of the internal air passage that allows the insertion of a pressing pin protruding from the contact head of the air blowing means, and the upper part of the valve stem is held elastically by a spring member in the recess. 2. The neck type and core type mold unit according to claim 1, wherein the tip opening of the air passage is opened by the pressing force of the pressing pin.   The base plate has a receiving member for the mold mounting plate on both sides of the lower surface in the mold opening and closing direction, a hanging pin that is screwed through the base plate, and a base that constantly supports the hanging pin upward. With a spring member in the upper part of the plate, the mold opening / closing plate fitted to the receiving member is pulled to and from the lower surface of the base plate so that it can be separated from the base plate against the spring member by pressing the suspension pin. The neck-type and core-type mold unit according to claim 1, wherein the mold unit is configured.

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