ROTARY MOLDING MACHINE

Abstract: This invention relates to a rotary molding machine for molding a preform and hollow molded articles having a con­ struction wherein a round transfer disc (10) having lip molds (18) at four sides of the lower side surface is supported rotat­ ably at the center by a rotary shaft above a machine bed (1), and the stop positions of the lip molds (18) are used respec­ tively as an injection molding operation part, a temperature controlling part, a stretch-blow molding operation part and a molded article withdrawing part to dispose molds (15, 16) and other devices. The rotary shaft of the transfer disc (10) con­ sists of a piston (8) of an elevation cylinder (5) and this piston (8) and a driving shaft (7) of a driving device (6) for inter­ mittent rotation are connected in a free state with respect to an axial direction so that the piston (8) can move up and down or intermittently rotate the transfer disc (10) with respect to each mold (15, 16).

Description: Technical Field This invention relates to a rotary type molding machine which can be utilized for a continuous molding of a preform or in the case where molding of a preform to orientation blow molding of a hollow molded product are continously carried out. Document US-A-3 944 643 discloses a rotary type molding machine comprising : a transfer plate rotatable about a vertical axis and disposed upwardly of a plurality of operational stations including an injection molding station, an orientation blow molding station, a temperature control station and a molded product removing station, a plurality of lip molds, also serving as holders for a preform and a hollow molded product, supported by the transfer plate, said lip molds being effective for interacting with said operational stations at stop positions, driving means for rotating the transfer plate about said vertical axis, However, a molding machine of this conception involves a problem that the operational stations required for molding are moved up and down and therefore the vertically-moving weight is great and increases as the molding machine becomes large in size. Particularly, when the vertically-moving stroke increases which is the case when longitudinally lengthy products are molded, the downwardly moving speed is accelerated so that the lip mold may come into collision with the mold, thus requiring a buffer means. An injection orientation blow molding machine for hollow molded products which are longitudinally lengthy such as bottles has been desired to be further improved. DISCLOSURE OF THE INVENTION An object of this invention is to provide a new rotary type molding machine in which an injection mold is secured to a machine bed side so that an injection device may be always placed in nozzle touch to effect molding, and a vertically-moving weight is reduced and a vertically-moving speed is not accelerated due to a load, and even if a verticall-moving stroke is large, opening and closing of a lip mold at a high speed can be carried out smoothly. Another object of this invention is to provide a new rotary type molding machine in which, unbalance load, eccentricity or the like are avoided, and despite the use of the machine for a long period of time, the transfer plate is not inclined to impair rotation and a deviation in mold opening and closing will not occur. For achieving the aforesaid objects, this invention provides a rotary type molding machine as defined in claim 1. It is known from publication DE-A-2537185 to move transfer arms in a rotary molding machine by means of a stationary cylinder having a piston movable vertically and coupled to the arms, and to rotate the transfer arms by means of a stationary driving device rotating the said piston but in this machine, the transfer arms carry relatively heavy blow mandrel assemblies and the driving device is disposed on the fixed bed of the machine. Further one of the blow molding stages is always free and that is no use. Preferably, the support body is not limited to a plate-like body but may be a frame mounted over tie bars stood upright in the periphery of the machine bed. The piston of the cylinder of said moving means and the driving shaft for the driving device are connected through a spline, the piston being rotated along with the driving shaft but only the piston being moved in an axial direction and moved up and down along with the transfer plate. The aforementioned injection molding operation portion is equipped with an injection mold but the mold in the orientation blow molding operation portion is changed to a cooling mold when the rotary molding machine is used for continuous molding of a preform. With the above-described structure, by the extension of the vertically-moving piston of the cylinder. The transfer plate is moved upward or downward so that the mold and lip molds are closed. When the piston is contracted, the transfer plate is moved upward or downward so that the lip molds are separated from the mold and standby at a fixed level position. In such state, when the driving device is operated, the piston along with the driving shaft are rotated through the spline. Thereby, the transfer plate at the end of the piston also rotates so that the preform or molded product held by the lip mold rotates to the succeeding operation portion and stops. BRIEF DESCRIPTION OF THE DRAWINGS The drawings schematically show one embodiment of a rotary type molding machine according to this invention. FIG. 1 is a longitudinal sectional side view when mold is opened in a first embodiment; FIG. 2 is a longitudinal sectional side view when mold is closed; FIG. 3 is a partly cutaway plan view; The drawings illustrates a rotary type molding machine in the case of carrying out injection orientation blow molding. BEST MODE FOR CARRYING OUT THE INVENTION FIGS. 1 and 2 are respectively longitudinal sectional side views of an injection molding operation portion and an orientation blow molding operation portion which are positioned opposedly, in which tie bars 2, 2 are stood upright at four locations in the periphery of a machine bed 1. A plate-like support body 3 is horizontally secured to the tie bars 2, 2 in a fixed spaced relation with a flat base plate 4 on the machine bed. A hydraulically-operated cylinder 5 having a vertically moving piston 8 is longitudinally provided in the central portion of the support body 3, and an intermittently rotating driving device 6 in the form of a hydraulic oscillation motor whose rotational angle is 90° is connected to the top of the cylinder 5. A driving shaft 7 of the driving device 6 is inserted into the vertically-moving piston 8 of the cylinder 5 and connected to the piston 8 by way of a spline 9. A central portion of a transfer plate 10 is connected to the lower end of the piston 8 whereby the transfer plate 10 is moved up and down by the vertically-moving piston 8 and is intermittently rotated every angle of 90° by the driving device 7. A working space is formed between the transfer plate 10 and the machine bed 1 for utilization similarly to the conventional molding machine of this kind, and four portions are utilized as an injection molding operation portion, a temperature control operation portion, an orientation blow molding operation portion and a molded production removing operation portion, respectively. Upwardly of the transfer plate of the injection molding operation portion, a clamping device 11 in the form of a hydraulic cylinder is fixedly provided on the tie bars 2 and 12, and a temperature control device 25, an orientation blowing device 13 and a molded product removing device 26 are provided on the respective operation portions of the support body 3. Although not shown, an air cylinder for vertically moving members to be operated or the like is provided on each of these devices similarly to prior art devices. Furthermore, an injection mold 15 provided at its lower part with a hot runner block 14 is upwardly secured onto the base plate 4 of the injection molding operation portion, and a blow mold 16 is provided on the base plate 4 of the orientation blow molding operation portion so that it may be laterally opened and closed by hydraulically-operated opening and closing cylinders 17 and 17. Four lip molds 18 and 18 for closing the molds are provided in a fixed spaced relation in the periphery of the lower surface of the transfer plate 10, and an injection core 20 and a blow core 21 at the end of a clamping member 19 are inserted into the lip molds 18 and 18 while extending through the member receiving holes 3a and 10a from the support body 3 and the transfer plate 3. In the above-described rotary type molding machine, when the cylinder 5 is operated to extend the piston 8, the transfer plate 10 lowers from the support body side to the mold side, one lip mold 18 is closed in connection with the injection mold 15, the other lip mold 18 is closed in connection with the blow mold 16, and a preform 22 assumes a position of a blow cavity 16a. When the clamping device 11 and the orientation blowing device 13 are downwardly operated after the mold has been closed, in the clamping device 11, the injection core 20 extends through the support body 3, the transfer plate 10 and the lip mold 18 and enters the injection cavity 15a, and the lower end of the clamping member 19 is pressed against the lip mold 18 to bring forth powerful clamping thereat. In the orientation blowing device 3, the orientation blow core 21 is inserted into a lip portion of the preform 22 from the member receiving holes 3a and 10a. In the injection molding operation portion, the resin is poured into the injection cavity 15a from the injection device 23 to mold the preform 22, and in the orientation blow molding operation portion, the preform 22 is axially oriented and expanded to the mold surface of the blow cavity 16a by blowing compressed air to mold a hollow product 24. After completion of the molding, the clamping device 11 and the orientation blowing device 13 are upwardly operated and returned to their original position, and the blow mold 16 is opened. However, when the piston 8 of the cylinder 5 is contracted, the transfer plate 10 is returned to the original position in the state wherein the preform 22 and the molded product 24 are held on the lip molds 18 and 18. When the driving device 6 is then rotated through 90° counterclockwise, the transfer plate 10 also rotates along with the piston 9 through 90° to transfer the lip molds 18 and 18 to the succeeding operation portion. Accordingly, by alternately carrying out the expansion operation of the piston of cylinder 5 and the rotational operation at fixed angle by the driving device 6, it is possible to continuously carry out opening and closing of the lip molds and the mold devices and intermittent rotational movement of the transfer plate. While the above-described embodiments have been described of the case where the rotary type molding machine is utilized as an injection orientation blow molding machine, it is to be noted in the present invention that the rotary type molding machine can be also utilized as a continuous injection molding machine for a preform. In this case, a blow molding device and a blow mold device are merely changed to a preform cooling device and a cooling mold device, though not shown in the drawings. Moreover, the rotational angle is not limited to 90° but the rotational angle of 120°, 180° or the like can be used according to the number of the molding operation portions to be set. INDUSTRIAL APPLICABILITY In this invention, as mentioned above, the rotational shaft of the transfer plate is constituted by the vertically-moving piston of the moving means, the piston and the driving shaft of the intermittently rotating driving device are connected in the state free with respect to the axial direction, and the transfer plate is provided so that the latter may be moved up and down and provided rotatably intermittently with respect to the molds. Therefore, the injection device can be always placed in nozzle touch with the injection mold secured to the machine bed for effecting molding. Furthermore, since only the transfer plate is moved up and down, the load is smaller than the prior art in which the upper base plate and the lower plate are moved up and down, and even if the vertically-moving stroke is large, the high speed opening and closing can be carried out smoothly and the unbalance load, eccentricity and the like are hard to occur, whereby the machine of the present invention can be widely utilized.

Claims: A rotary type molding machine comprising : a transfer plate (10) rotatable about a vertical axis and disposed upwardly of a plurality of operational stations including an injection molding station, an orientation blow molding station, a temperature control station and a molded product removing station, a plurality of lip molds (18), also serving as holders for a preform and a hollow molded product, supported by the transfer plate, said lip molds being effective for interacting with said operational stations at stop positions, driving means (6,7) for rotating the transfer plate about said vertical axis, characterized in that said operational stations are disposed on a fixed bed (1) of the machine, moving means (5,8) are provided for moving the transfer plate vertically along said axis, up and down relative to said machine bed, said moving means comprise a stationary cylinder (5) installed on a fixed support body (3) disposed upwardly of said transfer plate (10) and having a piston (8) movable therein vertically and coupled to said transfer plate for moving the same vertically up and down, said driving means comprise a stationary driving device (6) provided on said cylinder (5) to rotate a driving shaft (7) coupled to said piston (8) to rotate said piston to thereby rotate said transfer plate, said driving shaft being coupled to said piston in a manner which maintains a driving connection while allowing the piston to move vertically in axial direction. A rotary machine according to claim 1, wherein said driving shaft (7) is coupled to said piston (8) of the moving means by a spline (9). A rotary machine according to claim 1 or 2 wherein said cylinder (5) of the moving means and said driving device (6,7) are positioned in the center of rotation of said transfer plate (10). A rotary type molding machine according to any of claims 1 to 3 wherein said support body (10) is mounted over tie bars (2,2) located in the periphery of the machine bed (1). A rotary type molding machine according to any of claims 1 to 4, wherein the mold in said injection molding operation portion comprises an injection mold (15), and the mold in said orientation blow molding operation portion comprises a blow molding mold (16). A rotary type molding machine according to any of claims 1 to 4, wherein the mold in said injection molding operation portion comprises an injection mold, and the mold in said orientation blow molding operation portion comprises a cooling mold.

Inventors: NAKAMURA YOSHINORI NISSEI ASB, NAKAMURA, YOSHINORI NISSEI ASB MACHINE CO., LTD.
Applicants: NISSEI ASB MACHINE CO LTD, NISSEI ASB MACHINE CO., LTD.
Application year: 1988
Main classification: B29C49
IPC codes: B29C49, B29L22