SECONDARY INJECTION MOLDING MACHINE FOR HOLLOW MOLDED ARTICLES

Abstract: A secondary moulding machine is claimed which enables injection moulding of a handle, a base cup etc., integrally with the drum, bottom etc. of a hollow container moulded from a synthetic resin having a small thickness. The machine comprises an insert mechanism consisting of a rotary member fitted to a support pole on a machine base in such a manner as to be capable of moving vertically, and a horizontal moulding gripper mounted to the rotary component; a vertical mould clamp mechanism having an upper mould clamp disk which moves vertically to open and close a mould and is connected to the rotary component; a secondary moulding die having a cavity complementary to a hollow moulded article and a secondary moulding cavity and freely openable vertically; and an air blower connected to a blast core.

Description: FIELD OF THE ART This invention relates to a molding machine which can secondarily injection-mold a handle, a base cup and the like on a synthetic resin hollow product such as a blow-molded bottle. BACKGROUND An injection blow molding machine capable of primarily injection molding a base cup on a bottom of a thin-wall synthetic resin container oriented blow molded has been already known from Japanese Patent Application Laid-Open Publication No. 58-194520. The above molding machine is designed so that a hollow molded product such as a bottle oriented blow molded is moved, without being removed from a transfer plate, to a secondary molding mold provided adjacent to a blow molding mold, and an internal pressure is applied under the attitude of the product oriented blow molded to inject a base cup. A secondary molding of a handle to a hollow molded product oriented blow molded is disclosed in EP-A-0232207 Also in this molding method, an internal pressure is applied to a hollow molded product to injection mold a handle on a thin-wall body portion but this application discloses no apparatus required for molding other than a molding mold provided with a cavity having the same shape as said hollow molded product and provided with a secondary molding cavity for molding the handle. It is convenient to carry out the secondary molding of a handle or the like while holding a hollow molded product on the side of a transfer plate as in the above-described molding machine in terms of supplying a hollow molded product to a secondary molding mold. A relative position between a hollow molded product as a member to be molded and a secondary molding mold can be easily coincided. In this case, however, a series of operations comprising injection molding of a parison, orientation blow molding of a hollow molded product and secondary molding are continuously carried out. Therefore, this system can be employed for a molding method generally called a hot parison system but cannot be employed for a cold parison system in which a molded parison is orientation blow molded later by other apparatus. Problems encountered in the case where a handle or the like is injection molded to a hollow molded product after removed from an orientation blow molding machine lie an insert of a hollow molded product into a mold, and a connection between an air blowing device for applying an internal pressure and a hollow molded product. It is therefore desirous to develop a secondary injection molding machine which is easy in insert, which can positively provide a connection between a hollow molded product within the mold and a blow core, and which can supply an internal pressure enough to withstand an injection pressure into a hollow molded product. DISCLOSURE OF THE INVENTION Accordingly, this invention has been achieved in view of the aforementioned circumstances. An object of this invention is to provide a secondary injection molding machine for inserting a hollow molded product such as a bottle made of synthetic resin into a secondary molding mold to secondarily injection mold a handle on a body portion or a base cup or the like on a bottom portion thereof, in which an insert of a hollow molded product into a secondary molding mold can be smoothly done and pressing of a hollow molded product within the mold by air pressure can be positively carried out. For achieving the aforesaid object this invention provides a injection molding machine as defined in claim 1 The above-described secondary molding mold has the same cavity as a premolded hollow molded product and a secondary molding cavity, and the above-described molded-product holding device has a chuck holding an opening and a blow core having a fore end which extends through the chuck positioned within the opening, whereby a mouth portion of a hollow molded product is held and fixed, and an internal pressure of air pressure is applied thereto to render possible injection molding of secondarily molded parts such as a handle and the like in position as required. With the above-described structure, a hollow molded product is laterally held by the holding device of the insert mechanism, at the position opposite to the clamping mechanism. The insert mechanism rotatably moves a hollow molded product as well as a holding device to the secondary molding mold in an opened state. When the insert mechanism stops, closing starts and the upper clamping plate moves down. Since the upper clamping plate and the rotational member of the insert mechanism are connected, the insert mechanism is moved down simultaneously and insertion of a hollow molded product into the secondary molding mold is carried out. When clamping is completed, the air blowing device is connected to the blow core through which the chuck of the holding device extends, and air is pressed into the hollow molded product to apply an internal pressure thereto. Thereafter, a molten resin is injected and filled in the secondary molding cavity within the mold to mold a secondary molded part on the body portion or bottom portion of the hollow molded product. Accordingly, a hollow molded product is not deformed due to an injection pressure. In closing, a hollow molded product is also moved up and down owing to upward and downward motion resulting from the connection between the insert mechanism and the upper clamping plate to effect insert or release, whereby even at the time of transfer caused by rotation, it is possible to accurately perform a positioning of a hollow molded product with respect to a mold. BRIEF DESCRIPTION OF THE DRAWINGS The drawings schematically show one embodiment of a secondary injection molding machine for a hollow molded product according to this invention. FIG. 1 is a front view. FIG. 2 is a plan view. FIGS. 3 and 4 are respectively sectional views showing the holding of a hollow molded product. FIGS. 5 and 6 are respectively sectional views showing the insert state. FIG. 7 is a plan view of a mold showing the state before and after the secondary molding. BEST MODE FOR CARRYING OUT THE INVENTION The molding machine shown in the drawings is a molding machine for secondarily molding a handle on a body portion of a thin-wall bottle orientation-blow molded. Adjacent to a machine bed 1, a column 3 of an insert mechanism 2 and a vertical clamping mechanism 4 are provided. The insert mechanism 2 is composed of a rotational member 5 provided on the column 3 rotatably and movably up and dawn by use of a bearing, a spline shaft or the like, and a lateral holding device 6 mounted on the under-side of the rotational member 5. The holding device 6, details of which are shown in FIGS. 3 and 4, is composed of a holding body 7 affixed to a lower edge 5a of the rotational member 5, a blow core 8 extended into the holding body 7, a chuck 9 that may be opened up and down provided in the periphery of the fore end of the blow core 8, and an opening and closing cylinder 11 of the chuck mounted on a holder 10. A spring 8a is inserted between the chuck 9 and a core shoulder. The clamping mechanism 4 is of the vertical type in which an upper clamping plate 12 is positioned on the machine bed, and a lower clamping plate and a clamping cylinder are positioned within the machine bed though not shown, the upper clamping plate 12 being moved up and down together with a tie bar to effect opening and closing. The upper clamping plate 12 of the clamping mechanism 4 and the rotational member 5 of the insert mechanism 2 are connected with each other so that the insert mechanism 2 is moved up and down together with the upper clamping plate 12. On the upper clamping plate 12 and a lower clamping plate (not shown), a divisional secondary molding mold 13 shown in FIG. 5 and thereafter is mounted. This mold is provided with a cavity 15 having the same shape as a premolded bottle 14 made of synthetic resin and a secondary molding cavity 16 for molding a handle, and further provided with a fastening portion 17 of the chuck 9. An air blowing device indicated at 18 is mounted on the machine bed on the side of the column 3. When the holding device 6 is moved down and a plug 19 provided directed at the clamping mechansim is pushed out by a cylinder 20, the air blowing device 18 comes into contact with a rear end 8b of the blow core 8 and urges the blow core 8 against the spring 8a. The operation of the machine will be described hereinafter. An opening of the bottle 14 is fitted into the fore end of the blow core 6, as shown in Fig. 3, after which the chuck 9 is closed to hold the mouth portion of the bottle to hold the bottle 14 horizontally as shown in Fig. 4. Then, the insert mechanism 2 is rotated counter-clockwise through 90 degrees by the rotational member 5 to move the bottle 14 to the opened secondary molding mold 13 (see FIG. 5). After stop and when the clamping mechanism 4 is actuated to move the upper clamping plate 12 downwardly and to shift the mode to the closing step, the insert mechanism 2 is also moved down and the bottle 14 positioned in the mold is also moved downward. Closing as shown in FIG. 6 is carried out. When clamping further takes place, the chuck portion is held down by the fastening portion 17 so as to withstand internal pressure. Thereafter, the plug 19 of the air blowing device 18 is placed in pressure contact with the rear end of the blow core 8, and air pressure of approximately 30 kg/cm² is applied into the bottle through the blow core 8. After pressing, a secondary molding material is injected into the secondary molding mold 13 from the injection device 21 on the machine bed 1 disposed horizontally with respect to the clamping mechanism, and a handle 23 integral with a band 22 surrounding the secondary molding cavity 16 is produced by the resin filled into the secondary molding cavity 16. After molding, the upper clamping plate 12 is moved upward to effect opening, and at the same time, a projecting device 24 provided over both the mold and the holding device is moved upward whereby the holding body 7 and the bottle 14 are somewhat forced up, and releasing from a lower mold is effected. The bottle 14 having been subjected to secondary molding positioned in the mold is again returned to the insert position by the 90° rotation of the insert mechanism. A new bottle is insrted into the mold. INDUSTRIAL APPLICABILITY A secondary molding machine of this invention is designed so that a mouth portion of a hollow molded product is held by a blow core and a chuck, and after clamping, internal pressure can be applied while holding the mouth portion. Therefore, the hollow molded product is not deformed due to an injection pressure, and a handle or the like can be very easily subjected to secondary molding. In addition, positioning of a hollow molded product with respect to a mold can be accurately peformed by upward and downward motion resulting from a connection between an insert mechanism and an upper clamping plate. The aforesaid effects are great and very useful in industry, and the present machine is extensively utilized.

Claims: An injection molding machine for making a secondary molding on a hollow molded product having an opening comprising a secondary molding mold (13) provided with a cavity (15) having the same shape as said molded product and a secondary molding cavity (16), characterized in that it comprises a machine bed (1), a rotational member (5) provided movably up and down on a column (3) on the machine bed, an insert mechanism (2) mounted on the rotational member (5) and comprising a lateral molded-product holding device (6) said molded-product holding device having a chuck (9) for holding said opening and a blow core (8) having a fore end which extends through the chuck positioned within the opening, a vertical clamping mechanism (4) positioned adjacent to the insert mechanism and having an upper clamping plate (12) which is vertically moved for opening and closing said mold (13) and which is connected to the rotational member so that the insert mechanism (2) is moved up and down together with said upper plate (12), said secondary molding mold (13) being mounted on the clamping mechanism so that the secondary molding mold is opened and closed up and down when said upper clamping plate (12) is vertically moved; an injection device (21) on the machine bed disposed horizontally with respect to the clamping mechanism for injecting a molding material into the secondary molding mold (13), and an air blowing device (18) positioned on the side of the column and connected to the blow core at a descended position for applying an air pressure into said molded product. The injection molding machine according to Claim 1, wherein said rotational member (5) is provided rotatably and movably up and down on said column by use of a bearing, a spline shaft and the like, and said lateral holding device (6) is mounted on the underside of the rotational member. The injection molding machine according to Claim 1, wherein when the holding device (6) is moved down and a plug (19) provided on the side of the clamping mechanism is pushed out by a cylinder (11), said air blowing device (18) comes into contact with a rear end of said blow core and urges the blow core against a spring (8a). The injection molding machine according to Claim 1, wherein said mold comprises a cavity (15) having the same shape as a premolded bottle made of synthetic resin, a secondary molding cavity (16) for molding a handle, and a fastening portion (17) of said chuck (9).

Inventors: KOGA, KOUHEI
Applicants: NISSEI ASB MACHINE CO., LTD.
Application year: 1988
Main classification: B29C45
IPC codes: B29C45, B29L22