JPH08238650A - Mold apparatus for molding shutter for digital video disk - Google Patents

Abstract

PURPOSE: To prevent molding inferiority such as wall thickness irregularity by forming a gate as a direct hot gate having directionality along the longitudinal direction of a connection part to provide the same at the position corresponding to one end in the longitudinal direction of the connection part with respect to a cavity. CONSTITUTION: A gate 38 is provided at the position corresponding to the connection part 7 of a shutter 4. By this constitution, even if the gate 38 is only one with respect to one cavity 33, the cavity 33 is filled with a resin without bringing about filling insufficiency. The gate 38 is formed as a direct hot gate having directionality along the longitudinal direction of the connection part 7 to be arranged at the position corresponding to one end surface in the longitudinal direction of the connection part. By this constitution, the resin flowing in the cavity 33 from the gate 38 flows along the longitudinal direction of the connection part to flow in the parts corresponding to both opening and closing parts 6A, 6B without directly impinging against a first slide core and molding inferiority such as thickness irregularity can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold device for molding a shutter for a digital video disc, and more particularly to a gate.

[0002]

2. Description of the Related Art A digital video disc, as shown in FIG. 5, has an optical disk-shaped record carrier 2 in a diskette 1.
It is rotatably stored. The diskette 1 has openings 3 on both sides for exposing a part of the record carrier 2, and a shutter 4 for opening and closing the openings 3 is slidably assembled. The shutter 4 is an integrally molded product of synthetic resin such as polyacetal.
As shown in FIG. 5, it comprises a pair of opening / closing plate portions 6A, 6B which face each other with a small gap therebetween, and an elongated connecting portion 7 which connects end edges of the opening / closing plate portions 6A, 6B on one end side in the longitudinal direction. And
A recess 8 is formed on the outer surface of each of the opening / closing plate portions 6A and 6B on the side of the connecting portion 7, and through holes 9 and 10 are formed on both sides. Further, the connecting portion 7 has a through hole 11 continuous with the through hole 9 and a plurality of protrusions 12, 13, 14 formed on the inner surface thereof. The projection 12 has a shutter 4 for the diskette 1.
Claws 15 are formed to prevent the
A receiving convex portion 16 that abuts a spring portion on the diskette 1 side is formed on the disk. The opening / closing plate portions 6A and 6B have a thickness of about 1 mm, the connecting portion 7 has a thickness of about 2 mm, and the opening / closing plate portions 6A and 6B have a distance of about 6 mm.

FIG. 7 shows an example of a conventional mold device for molding the shutter 4. In the figure, 21 is a fixed type, 22 is a movable type, and these fixed type 21 and movable type 22
Is to open and close in the vertical direction in the drawing to form a cavity 23 in the shape of the shutter 4 between the molds when the mold is closed.
The open / close direction of the fixed die 21 and the movable die 22 is set in the longitudinal direction of the connecting portion 7. In addition, the movable mold 22 is actually
It has a plurality of slide cores for processing undercut shapes such as the protrusions 12, 13, and 14. In order to allow the resin to flow into the cavity 23, a runner 24 and a side gate 25 for communicating the runner 24 with the cavity 23 are formed between the fixed mold 21 and the movable mold 22 that are closed. The runner 24 is a cold type,
After the mold is opened, the resin solidified in the cavity 23, that is, the shutter 4 and the resin solidified in the runner 24 are taken out while being connected. Further, only one side gate 25 is provided for one cavity 23, and the side gate 25 is provided at a position corresponding to the outer surface end of the connecting portion 7.

[0004]

By the way, in the mold apparatus, the core 26 forming the inner surface of the shutter 4 is thin and is basically supported by only two sides. Therefore, blurring is likely to occur.
However, in the conventional mold device, the gate is connected to the connecting portion 7.
Since the side gate 25 was opened to a position corresponding to the outer edge of the, when filling the resin into the cavity 23,
As shown by the arrow in FIG. 8, the resin that has flowed in from the side gate 25 first strikes the core 26, and then this core
It goes around 26 and flows to the parts corresponding to the opening and closing plate parts 6A and 6B. Therefore, the core 26 is easily shaken, and the position of the core 26 becomes unstable. As a result, there is a problem that molding defects such as uneven thickness of the two opening / closing plate portions 6A and 6B are likely to occur.

SUMMARY OF THE INVENTION The present invention is intended to solve such problems, and an object thereof is to provide a mold device for molding a shutter for a digital video disc which can prevent molding defects such as uneven thickness.

[0006]

In order to achieve the above-mentioned object, the present invention provides a pair of opening / closing plate portions facing each other with a small gap therebetween, and an edge on one end side in the longitudinal direction of these opening / closing plate portions. In a mold device for molding a shutter for a digital video disc, which comprises an elongated connecting part integrally connected, a plurality of mold members are provided which open and close each other and form a shutter-shaped cavity between the molds when the mold is closed, The gate communicates with the cavity, and the gate is a direct hot gate having a directivity along the longitudinal direction of the connecting portion, and a position corresponding to one longitudinal end surface of the connecting portion with respect to one cavity. One is provided in.

[0007]

In the mold apparatus for molding the shutter of the digital video disk of the present invention, a plurality of mold members are closed at the time of molding to form a cavity between these mold members, and the cavity is formed with a resin from the gate. To fill. The gate is a direct hot gate, and has a directivity along the longitudinal direction of the connecting portion of the shutter, and is located at a position corresponding to one end face in the longitudinal direction of the connecting portion, so there is one gate for each cavity. The resin flowing into the cavity from does not directly hit the mold member forming the inner surface of the shutter, but flows from the portion corresponding to the connecting portion in the cavity to the portions corresponding to both opening and closing plate portions.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a mold device for molding a shutter for a digital video disk according to the present invention will be described below with reference to FIGS. The molded shutter 4 is the one shown in FIGS. 5 and 6 described above. The mold apparatus of this embodiment is of the hot runner type. Reference numeral 31 is a fixed type and 32 is a movable type. These fixed die 31 and movable die 32 are opened and closed in the vertical direction (Z direction) shown in FIGS. The cavity 33 is formed. The opening / closing direction (Z direction) between the fixed die 31 and the movable die 32 is set in the longitudinal direction of the connecting portion 7.

The fixed mold 31 includes a substrate 36 and a cavity 33.
The cavity insert 37, which is a mold member for forming the above, is fixed. The cavity insert 37 forms the vicinity of one longitudinal end surface of the connecting portion 7 of the shutter 4.
A direct hot gate 38 communicating with the cavity 33 is formed in the cavity insert 37. Gate 38
Is only one point for one cavity 33.
The gate 38 is oriented in the Z-direction (direction toward the movable die 32) and is located at one end face in the longitudinal direction of the connecting portion 7 and corresponding to the protrusion 13.

Further, the fixed die 31 is provided with a valve device 41 for opening and closing the gate 38. This valve device 41 is
A valve body having a resin passage 42 inside which communicates with the gate 38
The valve pin 44 is built into 43. The valve pin 44 is driven in the Z direction by a fluid pressure cylinder (not shown) and is removably fitted into the gate 38. Further, the valve body 43 is provided with a heater 45 for keeping the resin in the resin passage 42 in a molten state. Further, the resin passage 42 in the valve body 43 is
Familiar with runners.

The movable die 32 includes a substrate 51, a cavity 33
The core insert 52, which is a mold member for forming the core, is fixed.
The core insert 52 forms the vicinity of the other end face in the longitudinal direction of the connecting portion 7 of the shutter 4. Also, the substrate 51
Further, the core insert 52 has a first slide core 53 and a second slide core 5 which are mold members forming the cavity 33.
4, third slide core 55 and fourth slide core 56
Are slidably supported in the X direction or the Y direction orthogonal to the Z direction. The first slide core 53 moves in the X direction and forms the inner surface of the shutter 4. The second slide core 54 moves in the X direction and forms the outer surface of the connecting portion 7 of the shutter 4. The third slide core 55 moves in the Y direction, which is a direction orthogonal to the X direction,
The outer surface of one opening / closing plate portion 6A of the shutter 4 is formed. The fourth slide core 56 moves in the Y direction and forms the outer surface of the other opening / closing plate portion 6B of the shutter 4. The slide cores 53, 54, 55 and 56 are interlocked with the opening and closing of the fixed die 31 and the movable die 32 by the angular pins 57, 58, 59 and 60 fixed to the substrate 36 of the fixed die 31, respectively. It opens and closes. Angular pin
57, 58, 59, 60 are the corresponding slide cores 53, 54, 55,
The slide cores 53, 54, 55, 56 are located on a plane that includes the moving direction of 56 and the Z direction, and are inclined in directions away from each other in the Z-direction. It is inserted into each of the inclined holes 61, 62, 63, 64 having an inclination. In addition, on the substrate 36 of the fixed mold 31,
Locking blocks 65, 66, 67, 68 that finally regulate the positions of the slide cores 53, 54, 55, 56 when the mold is closed are fixed. These locking blocks 65, 66, 6
Reference numerals 7 and 68 are inclined surfaces that are orthogonal to the plane including the moving directions of the corresponding slide cores 53, 54, 55 and 56 and the Z direction and that are parallel to the corresponding angular pins 57, 58, 59 and 60, and correspond. It hits the slide cores 53, 54, 55, 56. Further, each of the slide cores 53, 54, 55, 56 has a spring 69, 70, 71, 72 mounted between it and the board 51 or the core insert 52.
Are urged in directions away from each other.

In addition to the cavity insert 37 and the core insert 52, four slide cores 53, 54, 55, 56 are provided as mold members for forming the cavity 33 because the recess 8 and the projection 12 are provided. This is to reduce the mold release resistance while processing undercut shapes such as 13, 14, and so on.

Next, the operation of the above configuration will be described. At the time of molding, first, the fixed die 31 and the movable die 32 are closed. With this mold closing, the first slide core 53 is moved in the X-direction by being driven by the angular pins 57, 58, 59, 60 on the fixed mold 31 side, and the second slide core 54 is moved to the X + direction.
Direction, the third slide core 55 moves in the Y + direction, and the fourth slide core 56 moves in the Y- direction. Then, each slide core 53, 54, 55, 56 is finally fixed type 3
It is pressed by the locking blocks 65, 66, 67, 68 on the first side and held in a closed state against the springs 69, 70, 71, 72. In this state, the cavity insert 37 of the fixed mold 31, the core insert 52 of the movable mold 32, and the slide cores 53, 5
A cavity 33 is formed between 4, 55 and 56.

After the mold is closed, the valve pin 44 moves in the Z + direction and the gate 38 is opened. In this state, the thermoplastic resin melted by heating flows into the cavity 33 from the gate 38 through the runner of the manifold 46 and the resin passage 42 in the valve body 43 and is filled therein. After the resin filled in the cavity 33 is solidified by cooling, the fixed die 31 and the movable die 32 are opened, and the shutter 4 which is the resin solidified in the cavity 33 is taken out. Before opening the mold,
The valve pin 44 moves in the Z-direction and the gate 38 is closed. With the mold opening, driven by the angular pins 57, 58, 59, 60, the first slide core 53 moves in the X + direction, the second slide core 54 moves in the X- direction, and the third slide core 54 moves.
The slide core 55 moves in the Y-direction, and the fourth slide core 56 moves in the Y + direction. The springs 69 and 7
As soon as the fixed mold 31 and the movable mold 32 start to open due to 0, 71, 72, the slide cores 53, 54, 55, 56 also start to open.
In this way, the molded shutter 4 is released. The removal of the slide cores 53, 54, 55, 56 in this manner prevents the undercut shapes of the recesses 8 and the projections 12, 13, 14 from interfering with the taking out of the shutter 4. The first slide core 53 forming the inner surface of the shutter 4 also has the protrusion 1
It only needs to move the length that 2, 13, 14 can escape.

According to the structure of the above embodiment, the gate 38 is provided at a position corresponding to the connecting portion 7 of the shutter 4, so that
Even if only one gate 38 is provided for each cavity 33, the resin can be filled in the cavities 33 without causing insufficient filling. Further, since the gate 38 is a direct hot gate having directivity along the longitudinal direction of the connecting portion 7 and is provided at a position corresponding to one end face in the longitudinal direction of the connecting portion 7, as shown by an arrow in FIG. The resin flowing from the gate 38 into the cavity 33 first flows along the longitudinal direction of the connecting portion 7, does not directly abut the first slide core 53, and opens and closes both sides from the portion corresponding to the connecting portion 7 in the cavity 33. It flows into the parts corresponding to the plate parts 6A and 6b. Therefore, it is possible to reduce the shaking of the first slide core 53, which is thin and has a small number of supporting portions, due to the force of the inflowing resin, and it is possible to prevent molding defects such as uneven thickness of the opening / closing plate portions 6A and 6B.

By the way, the through holes 9, 10,
The first slide core 53 is engaged with the other slide cores 54, 55, 56 at the portion 76 forming the 11, which also serves as a retainer for preventing the first slide core 53 from shaking. , By setting the position and direction of the gate 38 as described above,
The first slide core 53 can be made more stable.

In order to make the opening / closing direction of the fixed die 31 and the movable die 32 coincide with the longitudinal direction of the connecting portion 7, it is necessary to make the slide core
This is advantageous in that the strokes of 53, 54, 55, and 56 can be reduced, the release resistance can be reduced, and the projected area of the cavity 33 in the opening / closing direction is reduced,
It is also advantageous in taking a large number.

The present invention is not limited to the above embodiment, but various modifications can be made. For example,
In the hot runner type mold device, some kind of gate opening / closing mechanism is required, while in the above-mentioned embodiment, the gate is opened and closed.
Although 38 is mechanically opened and closed by the valve device 41, the gate may be opened and closed by melting or solidifying the resin in the gate portion by controlling the temperature of the hot tip. The division of the mold member forming the cavity, the drive mechanism of the slide core, etc. are not limited to those in the above embodiment.

[0019]

According to the present invention, in a mold apparatus for molding a shutter for a digital video disc, which comprises a pair of opening / closing plate portions and a connecting portion connecting these opening / closing plate portions, the gate has a longitudinal direction of the connecting portion. Since it is a direct hot gate having a directivity along with, and is provided at a position corresponding to one end face in the longitudinal direction of the connecting portion, one gate per cavity can be filled with resin without causing insufficient filling. At the same time, it is possible to reduce the shaking of the mold member forming the inner surface of the shutter due to the force of the inflowing resin,
Molding defects such as uneven thickness can be prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a mold device for molding a shutter for a digital video disc of the present invention.

FIG. 2 is a transverse sectional view of the same.

FIG. 3 is a plan view of the same as above, showing (a) above the center line.
Shows a fixed type, and (b) on the lower side shows a movable type.

FIG. 4 is a perspective view for explaining the operation of the same.

FIG. 5 is a perspective view of a digital video disc.

FIG. 6 is a perspective view of a part of the same shutter.

FIG. 7 is a cross-sectional view showing an example of a conventional molding device for a digital video disc shutter.

FIG. 8 is a perspective view for explaining the above problems.

[Explanation of symbols]

 4 Shutters 6A, 6B Opening / closing plate section 7 Connecting section 33 Cavity 37 Cavity insert (mold member) 38 Direct hot gate 52 Core insert (mold member) 53 First slide core (mold member) 54 Second Slide core (mold member) 55 Third slide core (mold member) 56 Fourth slide core (mold member)

Claims (1)

[Claims] 1. A shutter for a digital video disc, comprising a pair of opening / closing plate portions facing each other with a small gap therebetween, and an elongated connecting portion integrally connecting end edges of the opening / closing plate portions on one end side in the longitudinal direction. The molding die apparatus includes a plurality of die members that open and close each other to form cavities each having a shutter shape when the dies are closed, and a gate that communicates with the cavities. Of a shutter for a digital video disc, characterized in that a direct hot gate having a directionality along the longitudinal direction of the shutter is provided, and one is provided at a position corresponding to one end face in the longitudinal direction of the connecting portion with respect to one cavity. Molding equipment for molding.