JPS5850577B2 - Blow molding equipment for synthetic resin bottles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blow molding apparatus that can blow mold a bottomed parison of synthetic resin into a bottle and at the same time attach a base cup to the bottom of the bottle.

There are various types of synthetic resin bottles depending on their uses, and the molding methods include either extrusion molding and air blowing by closing the bottom of the parison, or direct air blowing of an injection molded parison with a bottom.

There are molding methods, and further molding methods in which an injection or extrusion molded parison is stretched in the axial direction and air blown after temperature adjustment.

However, no matter which method is used,
Due to problems with wall thickness distribution, the bottoms of synthetic resin items tend to break, and for items containing pressurized contents such as carbonated drinks, when the contents are sealed, the internal pressure is 3.
．． It is said that there should be no chance of rupture under conditions of 5 kg and a temperature of 55 degrees Celsius or less, that there should be no deformation in any part, and that the inside should be of a shape that is easy to clean.

For this reason, the bottom surface is now bulged outward into a spherical shape,
That is, it is formed with a round bottom to prevent further deformation due to internal pressure, and since it cannot stand upright as it is, a synthetic resin base cup is fitted and glued to the bottom to make it sit better.

This base cup device is made by applying adhesive to the bottom of a bottle obtained by blow molding a separately molded base cup, and applying pressure while the adhesive hardens.

If the bottle is bonded without applying pressure, the adhesive will cause the bottle to rise, and the thickness of the adhesive layer formed at the bonded area will vary, resulting in different heights of the bottle.

In order to attach the base cup without using adhesive, it would be best to use the already known insert method, but it is better to use a blow mold of a device that continuously performs injection molding and blow molding of the parison. It is almost impossible to set the base cup on the bottom of the blow mold due to the positional relationship of the blow mold, and special equipment is required to set the base cup on the bottom mold in accordance with the series of molding cycles. ing.

Therefore, the present inventor developed a means for transferring the bottom mold to the outside of the machine when the blowing mold is opened, and a means for transporting the bottom mold together with the set base cup from a pair of split molds so that the setting can be carried out outside the machine. We have previously developed a device consisting of a lifting means positioned in the blowing mold, but since this device uses the inside of the machine under the substrate as the moving space for the bottom mold, This required changes in the installation of hydraulic equipment and piping, and there were other problems, such as the need to drill through holes in the board for pulling in the bottom mold, and the strength of the board.

This invention makes it easier to set the base cup than the above-mentioned device, and moreover, the base cup can be automatically supplied and set above the substrate, so that only the lower structure of the split mold can be changed without changing the specifications of the substrate. Then, blow molding from the base cup insert to the bottomed parison bottle,
The present invention provides a blow molding device with a new configuration that can even attach the base cup and solves the problems of the previously developed device.

The present invention will be explained in detail below using illustrated examples.

The drawing shows a blow molding stage of an injection stretch blowing apparatus in which the injection molding stage, heating stage, blow molding stage, and mold release stage are arranged in order on all four sides of the substrate. 1 is the substrate, and 2 is the machine base. , 3 is a blow mold.

The blow mold 3 consists of a pair of split molds 5, 5 that are moved laterally on the substrate by hydraulic cylinders 4, 4, and a bottom mold 6 that is movable up and down in the lower part of the split mold. In addition, the bottom molds 6, 6 also serve as receiving members for the base cup I.

Between the bottom mold 6 and the substrate 1, the top surface of the bottom mold is located slightly below the bottom end of the base cup 7 after blow molding, and the bottle 8 that has been blow molded together with the base cup 7 can be held as it is. A bottom mold lowering space 9.9 sufficient to allow transverse transfer is formed by cutting the inside of the split molds 5,5.

Reference numeral 10 denotes a hydraulic cylinder for raising and lowering the bottom mold installed on the lower side of the machine. Rods 13, 13 for supporting the bottom mold are vertically connected to a seat plate 12 attached to the tip of a ram 11.
13 penetrate through holes drilled in the substrate 1, connect with the bottom molds 6, 6, respectively, and lower the bottom molds 6, 6 to the upper surface of the substrate.

Reference numeral 14 denotes a base cup insertion device, which is disposed on the side of the split mold 5.5.

This base cup insertion device has a pair of guide members 15, 15 provided horizontally between the split molds at a position that does not interfere with the transfer of the blow-molded bottle 8, and a space between the guide members. It consists of a supply plate 16 of a required length fitted so as to be able to move forward and backward, and each bottom mold 6 is inserted into a long hole 17 formed in the supply plate 16.
, 6 is provided.

This cup holding part 18.18 includes a fixed receiving piece 18a attached to one edge of the elongated hole 17, and a movable receiving piece 18b installed opposite to the fixed receiving piece 18a, and is always biased in the opening direction by a spring 18c. The movable receiving piece 18b is pressed by an operating punch 20 having a recess 19 to hold the base cup 7 together with the fixed receiving piece 18a in the elongated hole 17, and an air cylinder 21 mounted on the supply plate 16 Accordingly, the above-mentioned operating punch 20
is pushed out, and the recess 19 and the shaft 1 of the movable receiving piece 18b
8d, the movable receiving piece 18b is opened by the spring 18c, and the holding of the base cup 7 is released.

Next, to explain the operation, the parison 23 from the heating stage is sandwiched between the heating stage and the neck mold 25 by the rotation of the rotary plate 22, and before it is located in the center of the blowing mold 3 in the mold open state, the parison 23 is transferred to the supply plate 16. is sent out between the divided molds 5.5 by an air cylinder or a motor, while holding the base cup 7.7.

On the other hand, the bottom mold 6.6, which has been lowered onto the substrate, is raised to a fixed position by the operation of the hydraulic cylinder 10 and stopped.

When the cup holding portion 18.18 and the bottom molds 6, 6 are aligned, the operating punch 20 is pushed out by the air cylinder 21, the movable receiving piece 18b opens, and the base cup 7.7
is placed on the top surface of the bottom mold 6°6.

Then, the supply plate 16 is instead pulled back from the side between the split molds 5, 5 to the original position, and then the parison 2
3 will be transferred.

The insertion of the base cup 7 is performed from when the split mold 6.6 is opened and the pin 8 is transferred to the mold release stage to when the parison 23 is newly transferred to the blowing stage.

Also, if the base cup 7.7 is shallow and the parison 8 is short, the base cup 7.7 may be inserted after raising the bottom molds 6, 6 as described above, but if the parison 8 is long and the base If it extends into the cup, insert it with the bottom molds 6, 6 in a lowered position, and insert the parison 8.
is located between the split molds 5°5, then the base cup 7
．． 7, the bottom molds 6, 6 are raised to the regular position.

At this time, the split molds 5, 5 may be closed before or after the bottom molds 6, 6 are raised.

When the mold is closed as described above and air is blown, the bottom of the parison 23 expands to fill the base cup.
This results in a bottle 8 having a base cup I.

Next, the split molds 5 and 5 are opened and the bottle 8 is transferred to the mold release stage, but as mentioned above, the bottom of the base cup 7 is in contact with or has entered the top surface of the bottom mold 6, so Before or after the molds 5, 5 are closed, the bottom molds 6, 6 are lowered to the substrate 1.

As a result, the bottom molds 6, 6 are positioned below the bottom surface of the base cup, and the bottle 8 can be transferred to the mold release stage without changing.

As described above, the present invention provides a base cup which is provided with a descending space between the substrate and the bottom mold in the lower part of the blowing mold, and which is arranged on the side of the blowing mold, with the bottom mold serving as a receiving member for the base cup. Since the base cup from the insertion device can be inserted into the blow mold when the mold is opened, there is no need to pull the bottom mold into the machine stand and insert the base cup. The inside of the stand can be used for arranging hydraulic equipment, etc., like in the past.

Furthermore, by reducing the height of the bottom mold, only a small amount of space is required for lowering the bottom mold, and the present invention has features such as being applicable to existing injection stretch blow molding machines.

[Brief explanation of the drawing]

The drawing shows a blow molding apparatus for synthetic resin bottles according to the present invention.
Fig. 1 is a plan view, Fig. 2 is a longitudinal sectional front view taken along the line ■-■ in Fig. 1, Fig. 3 is a longitudinal sectional side view taken along the line 1-1 in Fig. 1, and Fig. 4 is a base cup. Fig. 5 is a longitudinal side view when the bottle is inserted, Fig. 6 is a longitudinal side view when the bottle is transferred, and Fig. 6 is a longitudinal side view when the
The figure is a plan view of the base cup insertion device, and Figure 7 is Figure 6.
It is a vertical sectional view taken along the line -■. 1... Board, 2... Machine stand, 3...
...Blowing mold, 5...Divided mold, 6...
・Bottom mold, 7...Base cap, 8...
・Bottle, 9...Descent space, 10...
- Hydraulic cylinder, 14... Base cup insertion device, 23... Parison.

Claims (1)

[Claims] 1. A pair of split molds is installed on a substrate so that they can be opened and closed, and a receiving member for the base cup is installed as a bottom mold in the lower part of the split mold so that it can be raised and lowered freely, and a required bottom is installed between the bottom mold and the substrate. A blow molding apparatus for synthetic resin bottles, characterized in that a mold lowering space is provided and a base cup insertion device is arranged on the side of a split mold.