JP2014069418A - Blow-molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blow-molding apparatus yielding a high production efficiency without requiring the exchange of lower pinch plates.SOLUTION: In a blow-molding apparatus including not only a lower pinch plate 20 fitted underneath a blow-molding mold 10 for nipping a parison 8 but also expander pins 30, multiple expander pins 30 are provided, each formed in the shape of a thin plate, and configured to be mobile virtually perpendicularly to the downward streaming direction of the parison 8. The lower pinch plate 20 is formed as multiple divided portions fitted in a state of being mobile toward and away from one another, whereas expander pin holes 24 and 25 for storing the respective expander pins 30 identical in number to the expander pins 30 are formed along the neighboring planes 27 thereof. The dimension of each of the expander pin holes 24 and 25 along the width direction thereof is identical to or slightly larger than the thickness of the corresponding expander pin 30, whereas the dimension of the former along the longitudinal direction thereof is a length according with the mobile range of the corresponding expander pin 30.

Description

  The present invention relates to a blow molding apparatus having a lower pinch plate which is attached below a blow molding die attached to a blow molding apparatus and sandwiches a parison and an expander pin which holds and expands the lower end of the parison. .

  Conventionally, in the production of a hollow body, for example, in the production of an automotive fuel tank made of a thermoplastic synthetic resin, a blow molding method has been often used because of the ease of molding the hollow body. In the blow molding method, a parison of a molten thermoplastic synthetic resin member is formed into a cylindrical shape and extruded from above, and the parison is sandwiched between molds and air is blown into the parison to manufacture an automobile fuel tank.

  As shown in FIG. 4, in the blow molding method, the blow molding die 110 is opened, and the parison 108 is caused to flow down during that time. At that time, an expander pin 130 that expands the end of the parison 108 is used in order to attach a built-in component inside the parison 108 or to make the parison 108 uniformly contact the blow molding mold 110 (for example, , See Patent Document 1).

  As shown in FIG. 5, a lower pinch plate 120 that holds the parison 108 is attached between the expander pin 130 and the blow molding die 110 for pre-blowing. The lower pinch plate 120 is formed of a first lower pinch plate 121 and a second lower pinch plate 122. The first lower pinch plate 121 and the second lower pinch plate 122 are close to each other on the proximity surface 127 and away from each other. It is slidably attached.

  Further, in the proximity surface 127 of the first lower pinch plate 121 and the second lower pinch plate 122, a pre-blow pin hole 123 for storing a pre-blow pin and expander pin holes 124, 125 for storing two expander pins 130, 130. Is formed. Therefore, when the parison 108 is sandwiched between the first lower pinch plate 121 and the second lower pinch plate 122, the pre-blow pin and the two expander pins 130 and 130 do not prevent the parison 108 from being sandwiched. Pre-blow air does not leak from the parison 108 sandwiched between the lower pinch plate 121 and the second lower pinch plate 122.

JP-A-6-278194

  However, when molding various types of blow-molded products with one blow-molding device, the blow-molding mold 110 is exchanged according to the blow-molded products, and the opening positions of the expander pins 130 and 130 are adjusted. In this case, the expander pin holes 124 and 125 of the lower pinch plate 120 need to be changed.

In order to change the expander pin holes 124 and 125, it is necessary to replace the lower pinch plate 120 or replace the portion where the expander pin holes 124 and 125 of the lower pinch plate 120 are formed. The production efficiency was not good.
Therefore, an object of the present invention is to provide a blow molding apparatus with high production efficiency that does not require replacement of the lower pinch plate 120 and the like when molding various types of blow molded products with the blow molding apparatus.

In order to solve the above-mentioned problems, the present invention of claim 1 is an extract which is attached below a blow molding die attached to a blow molding apparatus and holds a parison and expands while holding the lower end of the parison. In a blow molding apparatus having a panda pin,
A plurality of expander pins are provided so as to be close to the lower end of the parison, each formed in a thin plate shape, provided so as to be movable substantially perpendicular to the flow direction of the parison,
The lower pinch plate is divided into a plurality of parts, is attached so as to be close to and separable from each other, and forms the same number of expander pin holes as the expander pins for accommodating the expander pins along the proximity surface. Is a blow molding device characterized in that the dimension in the width direction is the same as or slightly larger than the thickness of the expander pin, and the dimension in the longitudinal direction has a length corresponding to the movable range of the expander pin. is there.

In the present invention of claim 1, a plurality of expander pins are provided so as to be close to the lower end of the parison, each formed in a thin plate shape, and provided so as to be movable substantially perpendicular to the flow direction of the parison. Yes. For this reason, when the parison flows down and is positioned below the blow mold, the lower end of the parison can be widened by the expander pin, and the parison is inflated uniformly without wrinkling, and the blow mold It can be brought into contact with the cavity surface of the mold, and the built-in component can be easily inserted into the parison.
Since the expander pin is formed in a thin plate shape, the contact area with the parison is narrow, and the parison and the expander pin do not adhere to each other.

  The lower pinch plate is divided into a plurality of parts and is attached so as to be close to and separable from each other, so that the blow mold is opened, the parison flows down, and the lower end of the parison is located below the blow mold. Sometimes the lower part of the parison can be positioned between the separate lower pinch plates. Further, when preblowing, the lower pinch plates sandwich the lower part of the parison together, and the lower side of the parison is kept airtight so that the air of the preblow can be prevented from leaking.

  The same number of expander pins as the expander pins were formed along the proximity surface. For this reason, when the lower pinch plate divided into a plurality sandwiches the lower part of the parison, the expander pin is stored in the expander pin hole, and when the lower pinch plate sandwiches the lower side of the parison, The expander pin can keep the lower side of the parison airtight without being in the way.

  The expander pin hole is formed such that the dimension in the width direction is the same as or slightly larger than the thickness of the expander pin. For this reason, when the lower pinch plate divided into a plurality sandwiches the lower part of the parison, the gap between the parts where the expander pin does not exist can be narrowed in the expander pin hole. It can be reliably closed and the lower side of the parison can be kept airtight so that the pre-blow air does not leak.

  The expander pin hole has a length in the longitudinal direction corresponding to the movable range of the expander pin. For this reason, when the lower pinch plate is closed, the expander pin can be freely positioned within the movable range, the types of blow molded products are different, and the positions of the blow mold and the expander pin are different. However, it is not necessary to replace the lower pinch plate, and production preparation is easy.

  The present invention of claim 2 is the blow molding device in which the dimension in the width direction of the expander pin hole is shorter than the total dimension of the thickness of the expander pin and the thickness of the parison.

  In the present invention of claim 2, the widthwise dimension of the expander pin hole is shorter than the total dimension of the expander pin wall thickness and the parison wall thickness. For this reason, when the lower pinch plate is closed, the lower part of the parison can be securely and airtightly held in the part where the expander pin exists in the part of the expander pin hole, and the expander pin exists. Even in the unexposed portion, the expander pin has a small wall thickness and can substantially hold the lower portion of the parison in an airtight manner.

  A third aspect of the present invention is a blow molding apparatus in which a hole for sandwiching a pre-blow pin is formed on a dividing surface of a lower pinch plate.

  According to the third aspect of the present invention, since the hole for holding the pre-blow pin is formed on the dividing surface of the lower pinch plate, when the lower pinch plate divided into a plurality holds the lower part of the parison, the pre-blow pin is held between It is possible to hold the lower side of the parison airtight without holding the pre-blow pin in the way.

  In the present invention, the expander pin hole is formed so that the width direction dimension is the same as or slightly larger than the thickness of the expander pin, so that the lower pinch plate divided into a plurality holds the lower part of the parison together. In addition, even if the expander pin is not present in the expander pin hole, the lower part of the parison can be reliably closed, the lower side of the parison can be kept airtight, and the pre-blow air can be prevented from leaking.

  Since the expander pin hole has a length in the longitudinal direction corresponding to the movable range of the expander pin, the expander pin can be freely positioned within the movable range, and the blow mold and the expander pin can be positioned freely. Even if the position of the panda pin is different, it is not necessary to replace the lower pinch plate, and the production preparation is easy.

It is a top view of the lower pinch board which is embodiment of this invention. It is an enlarged plan view of the right half of the 2nd lower pinch board of the lower pinch board which is embodiment of this invention. It is sectional drawing of the state which opened the blow molding die of the blow molding apparatus of this invention, and opened the front-end | tip of a parison with the expander pin. It is sectional drawing of the state which opened the blow molding die of the conventional blow molding apparatus, and opened the front-end | tip of a parison with an expander pin. It is a top view of the conventional lower pinch board.

A blow molding apparatus according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 3, the blow molding apparatus includes an extruder (not shown) that extrudes the synthetic resin forming the parison 8, a die head 6 that extrudes the synthetic resin from the extruder as the parison 8, and the parison 8. A blow molding die 10, a lower pinch plate 20 sandwiching the lower end portion of the parison 8, and an expander pin 30 extending the lower end of the parison 8. .

  As shown in FIG. 3, the blow molding die 10 is divided into two parts by a parting line, and is slid so as to open left and right by a blow molding die moving device (not shown). The blow molding die 10 has a cavity 11 in which a blow molded product is formed. When the blow molding die 10 is opened to the left and right, the parison 8 flowing down from the die head 6 is located at a position corresponding to the cavity 11. And the front-end | tip of the parison 8 flows down so that it may reach below rather than the lower end of the blow molding die 10. FIG.

  As shown in FIG. 3, an expander pin 30 and a lower pinch plate 20 that sandwiches the tip of the expander pin 30 and the lower end of the parison 8 are attached to the lower part of the blow molding die 10. As shown in FIG. 1, the lower pinch plate 20 includes a first lower pinch plate 21 and a second lower pinch plate 22 that are formed by dividing the lower pinch plate adjacent surface 27 into two rectangular plates.

In the present embodiment, two expander pins 30 and a first expander pin 31 and a second expander pin 32 are provided, but a plurality of expander pins 30 can be provided.
The first expander pin 31 and the second expander pin 32 are each formed in a thin plate shape. The first expander pin 31 and the second expander pin 32 can move left and right in the width direction (left and right direction in FIG. 1), not in the plate-like thickness direction, and with respect to the flow direction of the parison 8. Are provided so as to be movable substantially vertically. As the first expander pin 31 and the second expander pin 32, those having a width of 20 mm and a thickness of about 5 mm can be used.

  When the parison 8 flows down, the first expander pin 31 and the second expander pin 32 are inserted into the lower end of the parison 8 and then moved away from each other. Can be spread. Therefore, the parison 8 can be uniformly inflated without causing wrinkles, and the parison 8 can be brought into uniform contact with the cavity 11 surface of the blow molding die 10, and the built-in components are placed in the parison 8. When attaching, it is easy to insert a built-in component into the parison 8.

  Since the first expander pin 31 and the second expander pin 32 are formed in a thin plate shape, and the side ends of the thin plate plate come into contact with the parison 8, the contact area with the parison 8 is narrow. The expander pin 31 and the second expander pin 32 are not in close contact with each other, the parison 8 is not deformed abnormally, and the first expander pin 31 and the second expander pin 32 are separated from the parison 8 after blow molding. Is easy.

The first lower pinch plate 21 and the second lower pinch plate 22 are attached to the lower pinch plate holding frame 26 so as to be slidable in the opening / closing direction (vertical direction in FIG. 1) with a cylinder 28, respectively.
In FIG. 1, the first lower pinch plate 21 and the second lower pinch plate 22 are opened (a portion apart from the upper and lower sides of the lower pinch plate holding frame 26 in FIG. 1) and the lower pinch plate proximity surface 27 is closed. Both (the center portion of the lower pinch plate holding frame 26 in FIG. 1) are shown. With the first lower pinch plate 21 and the second lower pinch plate 22 opened, the lower part of the parison 8 flows down between them.

  The first lower pinch plate 21 and the second lower pinch plate 22 of the lower pinch plate 20 are attached so as to be openable and closable as described above. The pinch plate 21 and the second lower pinch plate 22 can be held between each other, and the lower side of the parison 8 can be kept airtight so that pre-blow air can be prevented from leaking.

  In the present embodiment, the lower pinch plate 20 will be described as an example in which the first lower pinch plate 21 and the second lower pinch plate 22 are divided into two pieces, but may be divided into three or more pieces. Is possible. Further, an example in which two expander pins 30 are used will be described, but three or more expander pins 30 may be used.

As shown in FIGS. 1 and 2, the lower pinch plate proximity surface 27 in which the first lower pinch plate 21 and the second lower pinch plate 22 are close to each other has two expander pin holes for sandwiching the expander pin 30. A first expander pin hole 24 and a second expander pin hole 25 are formed, and a pre-blow pin hole 23 that holds the pre-blow pin 40 is formed. When three or more expander pins 30 are used, the same number of expander pin holes as the expander pins 30 are formed. In this case, the lower pinch plate 20 can be divided into a plurality of pieces.
The pre-blow pin 40 will be described later. As shown in FIG. 2, the first expander pin hole 24 and the second expander pin hole 25 are respectively recessed by half in the lower pinch plate proximity surface 27 of the first lower pinch plate 21 and the second lower pinch plate 22. Form.

  When the first lower pinch plate 21 and the second lower pinch plate 22 sandwich the lower part of the parison 8 close to each other, the first expander pin 31 and the second expander pin 32 are respectively connected to the first expander pin hole. 24 and the second expander pin hole 25. When the first lower pinch plate 21 and the second lower pinch plate 22 sandwich the lower side of the parison 8, the first expander pin 31 and the second expander pin 32 are thin plate-like, so the first expander The pin hole 24 and the second expander pin hole 25 can accommodate the first expander pin 31 and the second expander pin 32. Therefore, the first lower pinch plate 21 and the second lower pinch plate 22 can be brought close to each other by the lower pinch plate proximity surface 27, and the lower side of the parison 8 can be kept airtight without being obstructed.

  For example, the first expander pin hole 24 and the second expander pin hole 25 have a width direction gap of about 8 mm, and the annular parison 8 has a thickness of about 12 to 30 mm. The lower side of the parison 8 can be securely clamped even at the hole 24 and the second expander pin hole 25.

  As shown in FIGS. 1 and 2, the first expander pin hole 24 and the second expander pin hole 25 have the same width dimension as the thickness of the first expander pin 31 and the second expander pin 32. Or slightly larger. For this reason, when the first lower pinch plate 21 and the second lower pinch plate 22 sandwich the lower part of the parison 8, the first expander pin hole 24 and the second expander pin hole 25, the first expander A gap between portions where the pin 31 and the second expander pin 32 are not present can be narrowed. Therefore, in any part of the first expander pin hole 24 and the second expander pin hole 25, the lower part of the parison 8 is reliably closed, and the lower side of the parison 8 is kept airtight, so that the pre-blow air Can be leaked.

  The dimension of the first expander pin hole 24 and the second expander pin hole 25 in the width direction can be shorter than the total dimension of the thickness of the expander pin 30 and the thickness of the parison 8. In this case, when the first lower pinch plate 21 and the second lower pinch plate 22 are closed, at the first expander pin hole 24 and the second expander pin hole 25, the first expander pin 31 and In the portion where the second expander pin 32 is present, the lower portion of the parison 8 can be securely clamped and the first expander pin 31 and the portion where the second expander pin 32 is not present The thickness of the expander pin 31 and the second expander pin 32 is small, and the total thickness of the two parisons 8 can be sandwiched between the first expander pin hole 24 and the second expander pin hole 25. The lower portion of the parison 8 can be substantially airtightly held.

  In the first expander pin hole 24 and the second expander pin hole 25, the longitudinal dimension has a length corresponding to the movable range of the first expander pin 31 and the second expander pin 32, respectively. For this reason, the first lower pinch plate 21 and the second lower pinch plate 22 can be closed regardless of the position of the first expander pin 31 and the second expander pin 32.

  Therefore, even if the types of blow molded products are different and the positions of the blow mold 10, the first expander pin 31 and the second expander pin 32 are different, it is not necessary to replace the lower pinch plate 20, and production preparation is possible. Easy. In addition, since the 1st expander pin 31 and the 2nd expander pin 32 are formed in the thin plate shape as mentioned above, the 1st expander pin hole 24 and the 2nd expander pin hole 25 are width | variety. And the parison 8 can be securely clamped.

  As shown in FIG. 1, a pre-blow pin hole 23 for accommodating the pre-blow pin 40 can be formed in the lower pinch plate proximity surface 27. In this case, the pre-blow pin 40 is attached below the lower pinch plate 20, and the tip of the pre-blow pin 40 can be accommodated in the pre-blow pin hole 23 of the lower pinch plate 20.

This pin is attached to the blow molding die 10 or the vicinity thereof and injects air for preblowing into the parison 8.
For this reason, when the first lower pinch plate 21 and the second lower pinch plate 22 are closed and the lower part of the parison 8 is sandwiched between each other, the pre-blow pin 40 is held in the pre-blow pin hole 23 so that the lower side of the parison 8 is The first lower pinch plate 21 and the second lower pinch plate 22 can be clamped. In this case, the pre-blow pin 40 does not get in the way, and the lower side of the parison 8 can be reliably closed and kept airtight.
Therefore, pre-blow can be performed by injecting air from the pre-blow pins 40 into the parison 8 to inflate the parison 8.

8 Parison 10 Blow Mold 20 Lower Pinch Plate 21 First Lower Pinch Plate 22 Second Lower Pinch Plate 23 Pre-Blow Pin Hole 24 First Expander Pin Hole 25 Second Expander Pin Hole 27 Lower Pinch Plate Adjacent Surface 30 Expander Pin 31 1st expander pin 32 2nd expander pin

Claims (3)

In a blow molding apparatus having a lower pinch plate attached below a blow molding die attached to a blow molding apparatus and holding a parison, and an expander pin that holds and expands the lower end of the parison.
A plurality of the expander pins are provided so as to be close to the lower end of the parison, each formed in a thin plate shape, and provided so as to be movable substantially perpendicular to the flow direction of the parison,
The lower pinch plate is divided into a plurality of parts, is attached so as to be close to and separable from each other, and forms the same number of expander pin holes as the expander pins for accommodating the expander pins along the proximity surface, The expander pin hole is formed such that the width direction dimension is the same as or slightly larger than the thickness of the expander pin, and the longitudinal dimension has a length corresponding to the movable range of the expander pin. Blow molding equipment.   The blow molding apparatus according to claim 1, wherein a dimension in a width direction of the expander pin hole is shorter than a total dimension of a thickness of the expander pin and a thickness of the parison.   The blow molding apparatus according to claim 1 or 2, wherein a hole for accommodating a pre-blow pin is formed in a dividing surface of the lower pinch plate.

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