JPH06218776A - Injection mold - Google Patents

Abstract

PURPOSE:To provide an injection mold which can correspond to products having various shapes by one mold and a cost and delivery of the mold can be performed by at least half of conventional ones. CONSTITUTION:A screw core 46 movable in an axial direction by a rotation of a core gear 44 is constituted of a hollow screw cylinder 48 having a screw 47, a core main body 49 which is inserted into the hollow screw cylinder 48 by fitting its rear end part in a core plate 33 and the tip member 50 fitted to the tip part of the core main body 49 in a detachable state by preventing the hollow screw cylinder 48 from being pulled off. The tip of the tip member 50 is inserted into a cavity 58 of a cavity plate 36 by forming a molding female screw 57 having the same pitch as those of a female screw 45 and the male screw 47 on the outer circumference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die for molding a double cap for a container.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, an example of a core pin gate type mold has been described above, in which a fixed side mounting plate 1, a runner plate 2, a core plate holding plate 3, a core plate 4, and a cooling plate 5 are provided. , A stripper plate 6, a movable side cavity plate 7, and a cavity plate holding plate 8 are sequentially arranged adjacent to each other, and a drive shaft 10 is arranged so as to penetrate through these plates. The drive shaft 10 is equipped with a sprocket 14 which stretches a chain 13 between the sprocket 12 of the motor 11. A main gear 15 is mounted on the drive shaft 10, an intermediate gear 16 is meshed with the main gear, and a core gear 17 rotatably mounted on the core plate 4 is meshed with the intermediate gear. When the drive shaft 10 is rotated by the rotation of the drive shaft 10, the screw core 18 integrally formed with the drive shaft 10 is rotated.
Is designed to be rotated. Reference numerals 19, 20, 21, 22 are bearings.

A sprue runner 23 in which the cavity plate 7 side serves as a gate for the axial inside of the screw core 18, the core plate pressing plate 3, the runner plate 2, and the mounting plate 1.
Are formed. A female thread 25 is formed on the outer peripheral surface of the tip of the screw core 18 fitted in the cavity 24 of the cavity plate 7. 26 is a runner repelling limiting bolt, 27 is a runner resistance pin, 28 is a repelling spring, and they are interposed by a stopper bolt 29 screwed to the cooling plate 5 so as to sandwich the stripper plate 6. 30 is a molded product, that is, a screw cap as a product.

[0004]

By the way, in the conventional mold as described above, since the screw core 18 rotated by the core gear 17 is integrally formed, it is necessary to mold products of different shapes. All of the screw cores 18 had to be correspondingly replaced, and a single mold could not be used for products of various shapes. In addition, the mold cost is high and the delivery time is also long.

Therefore, the present invention solves the problems of the conventional mold as described above, and can cope with products of various shapes with one mold, and the mold cost and delivery time are also compared with the conventional one. It is an object of the present invention to provide an injection molding die that can be manufactured in less than half that size.

[0006]

In order to achieve the above object, the present invention relates to a mold for injection molding as described above, in which a core gear is rotatably mounted on a stripper plate, and a screw is formed on the core gear. It has a threaded male screw and is provided with a threaded core that is axially movable by rotation of the core gear. The screw core includes a hollow threaded cylinder having a male thread, a core main body in which the rear end of the hollow threaded cylinder is fitted and inserted into a core plate, and a rear end of the core main body at the tip of the core main body. And a tip member detachably attached to prevent the hollow screw cylinder from coming out. A molded female screw having the same pitch as the female screw and the male screw is formed on the outer peripheral surface of the tip of the tip member and is fitted into the cavity of the cavity plate.

[0007]

As described above, since the screw core is composed of the hollow screw cylinder, the core body and the tip member as described above, the tip member is detached from the core body and separately prepared for molding products of different shapes. Need only be installed, and there is no need to replace the other core bodies or hollow screw cylinders that make up the screw core.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing a closed state of an injection molding die of an embodiment of a core pin cavity pin gate die of the same type as the conventional one of the present invention, and FIG. 2 is an enlarged sectional view of a molding die portion. Is. In FIG. 1, 31 is a fixed side mounting plate,
32 is a core plate retainer plate, 33 is a core plate, 34 and 35 are stripper plates, 36 is a cavity plate on the movable side, 37 is a cavity plate retainer plate, and a drive shaft 38 is arranged through each of these plates. There is. On the drive shaft 38, a sprocket 40 for suspending a chain 39 between the sprocket of a motor (not shown)
Is installed. A main gear 41 is mounted on the drive shaft 38, an intermediate gear 43 mounted on an intermediate shaft 42 is meshed with the main gear, and a core gear 44 is meshed with the intermediate gear. Reference numeral 45 denotes a screw formed on the core gear 44, and a screw core 46 is screwed into the female screw so as to be axially movable by the rotation of the core gear 44.

The threaded core 46 is a hollow threaded cylinder 48 having a male thread 47 screwed into the female thread 45 of the core gear 44, and a core inserted into the cored plate 33 by fitting the rear end portion thereof into the core plate 33. Body
49 and a tip member 50 detachably attached to the tip of the core body. An annular flange 51 that prevents the screw cylinder 48 from coming out is formed between the tip member 50 and the rear end of the core body 49 in the middle, and the lower end of the annular flange 51 is opened at the center of the tip of the core body 49. It is formed in the fitting part 53 that fits into the recess 52 that is formed.
A male screw 55 is formed on the inner periphery of 52 and is screwed with the screw 54. The female thread 54 and the male thread 55 are formed in the opposite threads when the screw cap described later rotates, and the core body 49 and the tip member 50 are rotated by the rotation of the screw cap.
The screwing of is tightened. The upper side of the annular flange 51 of the tip member 50 is formed in an upper end portion 56, and the tip end of the upper end portion is formed with a forming female screw 57 having the same pitch as the female screw 45 and the male screw 47 on the outer peripheral surface to form a cavity of the cavity plate 36. Fitted in 58.

Reference numeral 60 designates a core gear 44, a screw cylinder 48 and a tip member 50.
Hollow cylindrical stopper fixed to cover 60, 61 is stopper 60
A stopper bush fixedly fitted to the stopper 60 between the upper end 56 of the tip member 50 and the outer periphery of the tip member 50, and a screw cap fixing pin 62 as shown in FIG. Is provided. 63 is a screw cap, 64
Is a sprue runner, 65 is a passage for introducing cooling water,
Reference numeral 66 is a thrust bearing, and 67 is a holding ring.

The operation of the above embodiment will be described. 1 and 2 show the mold closed state of the injection molding cycle in which the screw cap 63 is injected and filled. When the mold is opened from this state as shown in FIG. 3, the motor is driven as described above to drive the drive shaft. When 38 is rotated, the core gear 44 is rotated via the main gear 41 and the intermediate gear 43. When the core gear 44 rotates, the screw core 46 is moved in the axial direction, and the core plate 33 separates from the core plate holding plate 32. Along with this, the screw cap 63 fixed to the pin 62 of the stripper bush 61 that rotates integrally with the core gear 44 and the stopper 60 is also screw core 46.
Rotate around and around the forming female thread 57 of.

Then, as shown in FIG. 3, the sprue 68 is a runner.
When the screw cap 63 is completely removed from the pin 64, the screw cap 63 is then pulled out from the pin 62 by suction using a vacuum not shown in FIG. 4 or various work robots or manually.
Further, the sprue 68 is pulled out by a chuck or the like. As described above, in this embodiment, the screw cap 63 is not repelled by the repelling spring 28 and released from the mold as in the prior art, but the screw core 46 is moved non-rotatably in the axial direction, and the core gear 44, the stopper 60, and The screw cap 63 is rotated by the rotation of the stripper bush 61 to be released from the mold, and at the time of this mold release, the pitch of the molded female screw 57 formed on the outer peripheral surface of the distal end member 50 of the screw core 46 is formed in the core gear 44, so that the screw 45 And the male screw 47 formed on the screw cylinder 48 of the screw core 46.
Since the pitch is the same, the screw of the screw cap 63 after molding will not be turned up. In addition, to form a screw cap with a different shape, the tip member 50 should be attached to the core body 49.
Loosen and remove the screws 54, 55, and attach a separately easy tip member for the screw cap. Therefore, it is not necessary to replace the other core body 49 and the screw cylinder 48 that form the screw core 46.

FIG. 5 shows another embodiment. This embodiment is basically different from the above embodiment in that it is a cavity pin gate type, whereas it is a core pin gate type.

71 is a fixed side mounting plate, 72 is a runner plate, 73 is a cavity plate holding plate, 74 is a movable side cavity plate, 75 and 76 are stripper plates, 77 is a core plate, 78 is a core plate holding plate, 79 is a mounting plate on the movable side. Since the configurations of the core gear 44 and the screw core 46 are the same as those in the above-mentioned embodiment, the same parts are designated by the same reference numerals and the description thereof is omitted. In this example, the hollow cylindrical stopper 60 and the stopper bush 61 are integrated. Reference numeral 80 is a drive shaft driving motor, and 81 is a passage for introducing cooling water.

The operation of this embodiment is almost the same as that of the above-mentioned embodiment, and the rotation of the core gear 44 moves the screw core 46 in the axial direction, whereby the core plate 33 is separated from the stripper plate 34, and the screw cap 63 is moved. It is released from the mold.
In order to prevent the threads of the screw cap 63 after molding from being turned over, and to form a screw cap of a different shape, remove the tip member 50 from the core body 49 and attach a separate tip member for the screw cap that is easy. The good things are the same.

[0016]

As described above, according to the present invention, since the screw core is composed of the hollow screw cylinder, the core body and the tip member as described above, the tip member is detached from the core body to facilitate the molding of products having different shapes. Since it is only necessary to attach the tip member and there is no need to replace the core body or the hollow screw cylinder that configures the screw core, it is possible to use products of various shapes with one mold. Moreover, the unit price of the mold cost can be reduced to about one-third and the delivery time can be halved compared with the conventional one, which is extremely practical.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a mold closed state of an injection molding cycle in an injection molding mold according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the molding die section of the above.

FIG. 3 is a cross-sectional view showing a state before the mold is released in the mold open state of the above.

FIG. 4 is a cross-sectional view showing a state where the mold is released in the same mold open state as above.

FIG. 5 is a cross-sectional view of an injection molding die of another embodiment in a mold closed state of an injection molding cycle.

FIG. 6 is a cross-sectional view of a mold closed state of a conventional example.

[Explanation of symbols]

 31 Mounting plate 32 Core plate retainer plate 33 Core plate 34, 35 Stripper plate 36 Cavity plate 37 Cavity plate retainer plate 38 Drive shaft 44 Core gear 46 Screw core 48 Hollow screw cylinder 49 Core body 50 Tip member 57 Molded female screw 58 Cavity 62 screw Cap retaining pin 63 Screw cap

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B29L 31:56 4F

Claims (1)

[Claims] 1. In an injection molding die in which a cavity plate, a stripper plate and a core plate are sequentially arranged adjacent to each other, a core gear is rotatably mounted on the stripper plate, and a screw and a screw fitting are formed on the core gear. A threaded core having an externally threaded male screw and movable in the axial direction by rotation of the core gear, the threaded core having a hollow threaded tube having the male thread, and a rear end portion of the hollow threaded tube on the core plate. A core body fitted and inserted,
The core body includes a tip member detachably attached to the rear end of the core body so as to prevent the hollow screw cylinder from coming out, and the tip of the tip member is attached to the outer peripheral surface. A mold for injection molding, wherein a molded female screw having the same pitch as the female screw and the male screw is formed and fitted into the cavity of the cavity plate.