JPH0412204B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to various synthetic resin products, particularly L-shaped,
The present invention relates to a blow molding method using a split mold that is effective for molding synthetic resin products having a bent shape such as an S-shape, a parison tip sealing device used therein, and a split mold device with the sealing device.

(Prior Art) Conventionally, as a blow molding method for synthetic resin bent products such as L-shaped and S-shaped, a pair of split molds is divided into three parts, each of which is an upper split mold, a lower split mold, and a split mold main part. Using a blow molding split mold in which the split mold upper part and the split mold bottom part cover the upper and lower half faces of the bent mold nest, and the split mold main part covers the remaining main part half surface of the bent mold nest, first, A pair of split mold main parts are closed to form a bent main part, and then the parison is lowered into the bent main part from the upper end of the opening, and is inserted into the bent main part from the upper end opening to the lower end opening. The above-mentioned parison is thereby caused to flow into the bent-shaped nest main part, and when the tip of the parison protrudes a required length from the lower end opening of the bent-shaped nest main part, the pair of split mold upper parts and The lower portions of the pair of split molds are closed, thereby enclosing the parison in a fully bent nest formed by the upper and lower parts of the pair of split molds and the main portion of the pair of split molds, and closing the lower portions of the pair of split molds. A blow molding method is known in which the tip of the parison is sandwiched and sealed by molding, and then air is blown into the parison to form the parison. but,
When implementing this conventional method, it is necessary to use a complex pair of split molds that are each divided into three parts: an upper part of the split mold, a lower part of the split mold, and a main part of the split mold. It requires a support structure and a drive mechanism for each of these parts, making the entire device complex and large.Also, the sealing of the parison tip is done by clamping the parison tip between the lower parts of a pair of split molds. There were some drawbacks, such as a flash line attached to the bottom of the product.

(Problems to be Solved by the Invention) An object of the present invention is to provide a blow molding method that eliminates the conventional drawbacks, a parison tip sealing device used therein, and a split mold device with the sealing device.

(Means for Solving the Problems) In order to achieve the above object, the blow molding method of the first invention of the present application includes a mold cavity half surface on the split mold closing surface, and a mold cavity from the upper end of the mold cavity half surface to the top of the split mold. A pair of split molds each having an open mold cavity half surface on the side surface consisting of an upper guide hole half surface and a lower guide hole half surface that open from the lower end to the other side of the split mold, respectively, are used. forming an open mold cavity between the split molds having an upper guide port and a lower guide port at both ends; The above-mentioned parison is conducted into the mold cavity by applying an airflow flowing to the outside from the guide port until the opening tip of the parison protrudes from the lower guide port to the outside for a required length; and the parison tip protruding from the lower guide port and blow-molding by blowing air into the parison with both the upper and lower guide ports closed, and the parison of the second invention of the present application. The tip sealing device is provided with a seal shutter that is movable back and forth in a substantially transverse direction of the guide hole to clamp the parison tip to the parison tip guide hole into which the open tip of the parison is to be introduced by suction. Further, the split mold device equipped with the above-mentioned sealing device of the third invention of the present application has a mold cavity half surface on the split mold closing surface, and a mold cavity half surface from the upper end of the mold cavity half surface to the split mold upper surface and from the bottom end to the split mold half surface. A pair of split molds that can be opened and closed, each having a half surface of an open-type mold nest consisting of a half surface of an upper guide port and a half surface of a lower guide port, each of which opens to the other side, and a lower guide port consisting of a half surface of the lower guide port of the pair of split molds. a parison tip guide tube having a parison tip guide hole that communicates with the open end of the parison; It is comprised of a seal shutter provided to open and close, and a suction means for drawing air into the mold cavity from the parison tip guide hole through the lower guide port.

Embodiments of the present invention will be described below with reference to the drawings. First, the apparatus used in the first invention will be explained.

In Figures 1 and 2, surface plates 2, 2 are fixed standing upright and parallel to each other at appropriate intervals on a base plate 1, and four slide rods 3 are supported horizontally between both surface plates 2, 2. At the same time, a pair of movable plates 4, 4 are horizontally slidably supported by the rod, and a pair of split molds 5, 5 are attached to opposing surfaces of both movable plates. 6',
Reference numeral 6' denotes a hydraulic cylinder for opening and closing the split mold horizontally fixed to the surface plates 2, 2, whose rams 7, 7 are fixed to the back surfaces of the movable plates 4, 4, and the cylinders 6',
By driving 6', the pair of split molds 5, 5 can be relatively moved in the horizontal direction for closing and opening.

The above-mentioned split molds 5, 5 have symmetrical L-shaped bent nest half faces 6, 6 on which an L-shaped bent nest should be formed, respectively, on their opposing closing surfaces. , as shown in the third figure, the half surface 8 of the upper guide opening that opens from the upper end of the bent half surface 6 to the upper side surface of the split mold 5 is connected from the lower end of the bent half surface 6 to the side surface of the split mold 5 in the substantially extending direction. The half faces 9 of the lower guide opening which are open to each other are opened respectively to form open half faces of the bent nest.

Reference numeral 10 denotes a parison extrusion die of an extruder, which is placed appropriately above the upper guide port formed by the upper guide port halves 8, 8 when the split molds 5, 5 are closed, and an air blow nozzle is located at the center of the lower surface of the die. 11, and in this example, the extrusion die 10 can be moved up and down.

The parison tip sealing device is as follows. In FIGS. 2, 3, and 4, two halves 12, 12 of the parison tip guide cylinder are placed on the side surfaces of the pair of split molds 5, 5 where the lower guide opening halves 9, 9 open.
are fixed with their bisected surfaces aligned with the split mold closing surfaces, and the guide cylinder halves 12, 12 have a parison tip guide hole penetrating through the bisected surfaces with a diameter large enough to introduce the parison. half surfaces 13, 13 are opened, respectively, and slit halves 14, 14 passing through the guide cylinder in the vertical and transverse directions are respectively formed, and as shown in FIG. Rectangular plate-shaped seal shutters 15, 15 having double width on the left and right sides of the slit half part 14 are slidably inserted into the upper and lower sides of the guide cylinder half part 14, and a bracket 1 is provided protruding from the upper and lower surfaces of the guide cylinder half part 12.
The rams 18, 1 of the seal shutter driving air cylinders 17, 17 are vertically supported by 6, 16.
The seal shutters 15, 15 mentioned above are fixed to the tips of 8. When the pair of split molds 5, 5 are closed, the pair of guide cylinder halves 12, 12 are closed accordingly, opening the guide hole consisting of the guide hole halves 13, 13 and the slit consisting of the slit half parts 14, 14, respectively. A seal shutter 15,1 is formed in the slit.
5 will be retained. The seal shutters 15, 15 are retracted from the guide hole when the air cylinders 17, 17 are driven backward, but when the air cylinders are driven forward, they advance to the center position of the guide hole and come together.

Next, the suction means is as follows. A suction cup 19 is supported on the outside on the axis of the parison tip guide tube formed by the parison tip guide tube halves 12, 12 when the pair of split molds 5, 5 are closed, so that the suction cup 19 can move forward and backward. The suction cup 19 has its open end directed toward the open outer end of the guide cylinder made up of the guide cylinder halves 12, 12, and connects an intake hose 21 to an intake hole 20 formed in the circumferential wall of the cup. It is connected to a device (not shown). The support structure of the suction cup 19 is such that a T-shaped guide groove 23 is provided on a bracket 22 fixed to the base plate 1, and a T-shaped slide plate 24 provided at the bottom of the suction cup 19 can freely slide into the guide groove 23. While engaging,
The ram 26 of the suction cup driving air cylinder 25 fixed on the bracket 22 is connected to the back surface of the suction cup 19, and when the cylinder 25 is driven and advances, its open end is used to guide the tip of the parison. It comes into contact with the outer end of the opening of the cylinder, and when it retreats, it separates from the parison tip guide cylinder.

Next, an example in which the above apparatus was used to blow mold a bent product will be described. In the state shown in FIGS. 1 and 2 in which the pair of split molds 5, 5 are open, first, the pair of split molds 5, 5 are closed by driving the hydraulic cylinders 6', 6', so that half of the mold cavity is formed between the two split molds. 6, 6, an open type bent type nest consisting of an upper guide port formed by upper guide port half surfaces 8, 8, and a lower guide port formed by lower guide port half surfaces 9, 9, and further, a parison tip guide cylinder half 12. , 12 guide hole half surface 13, 1
3 to form a guide hole.

Next, the air cylinder 25 is driven to bring the suction cup 19 into contact with the open outer end of the parison tip guide tube. In this state, the parison P is
When the suction cup 19 starts suction at the same time as it is pushed out and lowered into the bent nest from the upper guide port, it passes through the outside of the parison P from the upper guide port and moves inside the bent nest to the lower guide port. An airflow is generated that flows to the parison tip guide hole, and the parison is guided by this airflow into the bent nest and then smoothly introduced into the parison tip guide hole.

When the tip of the parison P slightly passes through the seal shutters 15, 15 in the tip guide cylinder, extrusion of the parison is stopped, then suction is stopped, and at the same time, the seal shutters 15, 15 are closed by driving the air cylinders 17, 17. The tip of the parison P is clamped and sealed between both shutters, and the lower guide port of the mold nest is isolated from the outside by the shutters. Retract the suction cup 19.

Next, the extrusion die 10 is lowered, and after closing the upper guide ports of the closing molds 5, 5 with its lower end surface, air is blown into the parison from the blow nozzle 11 of the extrusion die to inflate it, and a predetermined molding is performed. I do.

After molding, open the seal shutters 15, 15,
Next, the pair of split molds 5, 5 are opened, and the parison tip guide cylinder halves 12, 12 are opened accordingly to expose the bent molded product, and the molded product is cut from the following parison by the extrusion die 10.

The parison tip sealing device shown in FIG.
T-shaped guide groove 23a and T-shaped slide plate 2 on a
The guide tube 12a is supported by
has a parison tip guide hole 13a with the inner end facing toward the lower guide opening of the split molds 5a, 5a open but the outer end closed, and a seal shutter that opens and closes in the middle of the guide hole 13a. 15a, 15a are provided, and the guide hole 13a is provided at the closed end of the guide hole 13a.
An intake hole 20a that communicates with a and opens to the outside is provided, and the lower guide opening consists of the lower guide opening halves 9a, 9a of the split molds 5a, 5a, which are closed when the guide tube 12a advances by the drive of the air cylinder 25a. The lower guide port contacts the lower guide port in a communicating state, but is separated from the lower guide port when retracted, and the other structures are substantially the same as those in FIGS. 1 to 4.

The extrusion die in the above example is of a vertical motion type, but as shown in the sixth figure, a pair of split molds 5b, 5 are used.
The extrusion die 1 may be fixed at a position that enters into the upper guide opening half surface 8b, 8b of b.
A ventilation gap 27b is provided between the upper guide port half surfaces 8b, 8b, and the upper surface of the split mold. Further, as shown in FIG. 7, the lower surface of the extrusion die 10c is
There are some that are fixed at a position that abuts the upper side of the mold cavity, in which case, for example, a ventilation hole half 27c is provided that opens from the upper part of the mold cavity half 6c to the upper side of the split mold.

(Effect of the invention) According to the blow molding method of the first invention of the present application, especially L
It is possible to smoothly and reliably introduce a parison into a curved cavity such as a shape of a shape or an S shape to blow mold a curved product, and when carrying out the present invention, there is no need to use a complex structure divided into three parts as in the past. Unlike a split mold, it uses a pair of split molds that are not divided, so it can be carried out with a simple and compact device, and its value in use is extremely high.

According to the parison tip sealing device of the second invention of the present application, after the parison tip is introduced into the guide hole, the parison tip is clamped and sealed by the seal shutter that moves in a direction substantially transverse to the guide hole. It is possible to seal reliably without adding a flash line as in the conventional method.

According to the split mold device with a parison tip sealing device of the third invention of the present application, the structure is extremely simple compared to the conventional split mold device for blow molding bent products having a split mold divided into three parts, and the entire molding machine is By closing the seal shutter, the tip of the parison is sealed, and at the same time, the lower guide port of the mold nest is automatically shut off from the outside to prevent the next blowing process. You can prepare for it and get some benefits as well.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a partially omitted front view of the molding machine, FIG. 2 is a plan view of the same, and FIG.
The figure is a partially cutaway cross-sectional view taken along the line - in FIG. 2, FIG. 4 is an enlarged side view of a pair of parison tip guide cylinder halves, and FIG. 5 is an enlarged partially cutaway front view of another embodiment of the parison tip sealing device. 6 and 7 are partial front views showing other embodiments of the ventilation structure in the upper part of the split mold. 5, 5a, 5b, 5c... split mold, 6, 6a, 6
b, 6c...bent nest half surface, 8, 8a, 8b, 8c
... Upper guide port half surface, 9, 9a, 9b, 9c... Lower guide port half surface, 12... Parison tip guide cylinder half, 1
2a... Parison tip guide tube, 13... Parison tip guide hole half surface, 13a... Parison tip guide hole, 1
5, 15a... Seal shutter, 19... Suction cup, 21, 21a... Intake hose.

Claims (1)

[Scope of Claims] 1. On the closing surface of the split mold, a half surface of the mold nest, an upper half guide port and a lower guide port that open from the upper end of the half mold nest surface to the upper side of the split mold, and from the lower end to the other side of the split mold, respectively. A pair of split molds each having a half surface are used, and the pair of split molds are closed to form an open mold nest having an upper guide port and a lower guide port at both ends between the two split molds. By introducing the parison into the open mold cavity through the upper guide port and by applying an airflow passing through the mold cavity and flowing outside from the lower guide port, the parison is introduced so that its open end is above the Conducting the inside of the mold cavity until the required length protrudes from the lower guide port to the outside; Sealing the tip of the parison protruding from the lower guide port by clamping; and isolating both the upper and lower guide ports from the outside. A blow molding method comprising: blowing air into the parison in a state in which the parison is in a state where air is blown into the parison to perform blow molding. 2. A parison tip sealing device, which includes a parison tip guide hole into which the open tip of the parison is to be introduced by intake air, and a seal shutter that is movable back and forth in a substantially transverse direction of the guide hole to clamp the parison tip. . 3. An open-through mold consisting of a mold hole half surface on the split mold opening surface, and an upper guide port half surface and a lower guide port half surface that open from the upper end of the mold nest half surface to the upper side of the split mold, and from the lower end to the other side surface of the split mold, respectively. a pair of split molds that can be opened and closed, each having a nest half surface; a parison tip guide tube having a parison tip guide hole that communicates with an open end of a lower guide port formed by a lower guide port half surface of the pair of split molds; a seal shutter provided on the tip guide tube so as to be able to reciprocate in a substantially transverse direction of the guide hole in order to clamp the tip of the parison, and to open and close the guide hole; and a lower guide from the parison tip guide hole. A split mold device with a parison tip sealing device, comprising: a suction means for sucking air into the mold cavity through the mouth; 4. The parison tip guide tube consists of two halves in the longitudinal direction of the tube through which the guide hole passes, and the two halves are attached to the side surface where the lower guide opening half of the pair of split molds opens. The parison is fixed with its surface aligned with the split mold closing surface, the seal shutter is supported by one half of the parison tip guide tube, and the suction means is formed on the split mold closing surface. The split mold device according to claim 3, comprising a suction cup that is supported on the outer end of the guide hole opening of the tip guide tube so as to be able to move toward and away from it, and an intake hose that connects the suction cup to the vacuum device. 5 The parison tip guide cylinder is composed of a cylindrical body having a guide hole, and the cylindrical body supports the opening inner end of the guide hole so as to be able to move toward and away from the opening end of the lower guide opening formed when the split mold is closed. Claim 3, wherein the seal shutter is supported by the parison tip guide tube, and the suction means includes an intake hose connecting the outer end of the parison tip guide hole and the vacuum device. The split mold device described in .