JPH05261774A - Molding device - Google Patents

Abstract

PURPOSE:To reliably release a disk holding part having a reversely-tapered peripheral surface by blowing air in molding a tray of a compact disk containing case. CONSTITUTION:The rear surface of a tray 12 including the inner surface of a disk holding part 31 is molded by a fixed mold. The top surface of the tray 12 including the outer surface of the disk holding part 31 is molded by a movable mold 62. In the movable mold 62, an insert 67 for molding the disk holding part 31 is embedded in a core member 65. Air is blown against the tray 12 from around the insert 67 to release the disk holding part 31 from the movable mold 62. The insert 67 is provided with projected parts 71, 72 for forming through-grooves 33 and a circular open hole 34 of the disk holding part 31. In this manner, the through grooves 33 are closed by the projected parts 71, 72 without an air leakage until the tray 12 is levitated from the movable mold 62 by the wall thickness thereof.

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 tray or the like, which is a component of a compact disc storage case and holds a compact disc detachably.

[0002]

2. Description of the Related Art An example of a compact disc storage case will be described with reference to FIG. In FIG. 1, 1 is a compact disc, 2 is a circular opening hole formed in the center of the compact disc 1, 3 is a non-recording portion around the opening hole, and 4 is a periphery of the non-recording portion 3. It is a recording unit in. The illustrated compact disc 1 is a one-disc type that accommodates one compact disc 1 as described above, but a transparent base 11, a tray 12 attached to this base 11, and this tray 12 are Cover 13 that can be opened and closed freely
It consists of The cover 13 is pivotally attached to the base 11 by a hinge portion 14. In the following description, the hinge portion 14 side will be referred to as the rear side. The base 11
Is a molded product of transparent resin and has a shallow rectangular box shape. A finger-hanging notch 16, a pair of label retainer notches 17 and a plurality of tray mounting holes 18 are formed on both left and right sides of the base 11, respectively. Further, the cover 13 is also a molded product of transparent resin and has a rectangular shape, but a pair of label retainers 19 for holding a label are formed to project on the inner surfaces of the left and right sides. It should be noted that the hinge portion 14 is provided on the arm portion 20 projecting rearward from both left and right side portions of the cover 13. Further, as shown in FIG. 5, the tray 12 is a molded product of opaque resin and has a rectangular shape. And tray
An exposed portion 21 that closes the position between the arm portions 20 when the cover 13 is closed is formed at the rear portion of the portion 12 so as to bulge to the front side (the side shown in FIG. 4). A circular disk storage portion 22 is formed in the tray 12 by recessing it to the back side (the side shown in FIG. 5). Further, on both left and right sides of the tray 12, finger-hanging notches 23 are formed so as to face the disc storage portion 22, respectively, and a pair of label holding storage portions 24 are formed by being recessed to the back side. A pair of mounting projections 25 are formed on the outer surface. The notch 23 for hooking both fingers is continuous with the notch 16 for hooking both fingers of the base 11, and is for hanging a finger on the compact disc 1 when the compact disc 1 is attached or detached. Further, the label retainer storage portion 24 is provided with a notch portion 17 for storing the label retainer of the base 11.
The label retainer 19 of the cover 13 is stored when the cover 13 is closed. Further, the mounting projection 25 is engaged with the tray mounting hole 18 of the base 11,
The tray 12 is stopped on this base 11. A circular pedestal portion 26 is formed at the center of the disc storage portion 22 so as to bulge to the front side. The pedestal portion 26 has the non-recording portion 3 of the compact disc 1 mounted thereon and keeps the recording portion 4 of the compact disc 1 in a non-contact state with the bottom surface of the disc storage portion 22. Further, at the central portion of the pedestal portion 26, a disk holding portion 31 which elastically expands and contracts and engages with the opening hole 2 of the compact disk 1 in a disengageable manner to hold the compact disk 1 swells to the front side. Is formed. This disc holding portion 31 as a bulge portion is composed of a plurality of hook-shaped projections 32 arranged along the circumference, and by forming a through groove 33 between these hook-shaped projections 32, elastic expansion / contraction is possible. It is possible. Then, the through groove 33,
The circular openings 34 between the tips of the hook-shaped projections 32 extend radially from the pedestal portion 26. Further, the outer peripheral surface of the disk holding portion 31 is in a natural state and has an inverse tapered surface 35 whose diameter gradually increases toward the tip thereof. this is,
This is to ensure holding of the compact disc 1.

In injection molding of such a tray 12, a mold apparatus having a fixed mold and a movable mold which move in the directions indicated by A and B in FIG. 5 when the mold is opened is used. In the conventional mold device, the front side including the outer surface of the disc holding portion 31 in the tray 12 is formed by the fixed die, and the back side including the inner surface of the disc holding portion 31 in the tray 12 is formed by the movable die. Then, in order to prevent the traces of the gate from being seen and to enhance the commercial value, the gate is a tray 12 as a side gate as shown by a chain line arrow a in FIG.
Instead of the front side of the tray 12, for example, the reinforcing rib 36 on the front surface of the tray 12 is opened. In contrast, tray 12
The back side of the tray is formed by a fixed die, the front side of the tray is formed by a movable die, and the gate is used as a valve gate. The solid arrow b in FIG.
As shown by, the valve gate is opened to the reinforcing rib 37 and the like on the back side of the exposed portion 21. However, when the back side of the tray 12 is formed by the fixed mold in this way, the mold release resistance of the tray 12 from the fixed mold side becomes large because of its shape, so that in addition to the movable mold side, Also has a protruding pin. That is, as shown in FIG. 5, the protrusion pin traces 38 are shown by parallel hatching, a large number of protrusion pins are provided on the entire back surface of the tray 12 on the fixed mold side. On the other hand, as shown in FIG. 4, the protrusion pin traces 39 are shown by parallel hatching, the protrusion pins are provided only for the four label pressing accommodating portions 24 on the movable die side. This is because the protruding pin mark 39 in the label pressing storage portion 24 which is not the grain surface is relatively inconspicuous.
On the other hand, it is not preferable to provide the protruding pin on the bottom surface of the disk storage portion 22 or the pedestal portion 26, which is a grain surface, for reasons such as appearance. However, since the reverse taper surface 35 of the outer peripheral surface of the disc holding portion 31 formed by the movable die is an undercut in the die opening direction A of the movable die, the disc holding portion 31 has a movable die side. Some form of release from is required. An air blow is used as the mold releasing means.

Here, an example of a conventional mold apparatus of this type using air blow will be described with reference to FIGS. 8 to 10. 41 is a fixed mold, and 42 is a movable mold. The fixed mold 41 and the movable mold 42 move vertically with respect to each other in the drawing to open and close, and a cavity 43 having the shape of the tray 12 at the time of mold clamping.
Is formed inside. Then, the fixed mold 41
Has a cavity member 44 forming the back side of the tray 12 including the inner surface of the disc holding portion 31. On the other hand, the movable mold 42 has a core member 45 that forms the front side of the tray 12, and a nest 47 for air blow is inserted in a through hole 46 formed through the core member 45 in the vertical direction in the drawing. Is embedded and fixed. This nest 47 is a disc holder.
Although forming the outer surface of 31, the cavity surface at the upper end of the insert 47 in the drawing is sized to include the entire through groove 33. In addition, a concave groove-shaped air passage is formed on the outer peripheral surface of the insert 47.
48 is formed, and compressed air is supplied to the air passage 48 via an air passage 49 formed in the core member 45 or the like. The peripheral surface of the nest 47 and the core member
About 0.02 mm gaps 50 extending from the air passage 48 to the cavity 43 are formed between the peripheral surface of the through hole 46 of the 45 and about four places. Then, in the conventional mold device, the protrusions 51 and 52 forming the through groove 33 of the disc holding portion 31 and the circular opening 34 thereof are formed in the cavity member 44, and the recess 53 into which the protrusion 51 is fitted. Had formed a nest 47. Then, when the tray 12 is molded, the molten resin is poured into the cavity 43 from the gate while the fixed mold 41 and the movable mold 42 are clamped. Then, after the resin filled in the cavity 43 is solidified, the fixed die 41 and the movable die 42 are opened. At this time,
First, stick out the protruding pin on the fixed die 41 side to make the tray.
12 is released from the fixed mold 41 side. Then, eject the ejector pin on the movable die 42 side and blow the tray by air blow.
12 is released from the movable mold 42 side. That is, the air passage 4
The air is blown from 8 and 49 to the center of the tray 12 through the gap 50 between the insert 47 and the peripheral surface of the through hole 46 of the core member 45, so that the disk holding portion 31 is elastically deformed and is moved from the movable die 42. Leave.

[0005]

However, in the above-mentioned conventional mold device, the protrusions 51 and 52 forming the through groove 33 of the disc holding portion 31 and the circular opening 34 thereof are formed in the cavity member 44 of the fixed die 41. Since the tray 12 is formed, as shown in FIG. 8, when the tray 12 is slightly lifted from the movable mold 42, the air escapes through the through groove 33 of the disc holding portion 31 as shown by the arrow. Therefore, the air pressure is not effectively applied to the tray 12, and the disc holding portion from the movable die 42 side
There was a problem that the mold release of 31 was not reliably performed.

The present invention is intended to solve such a problem and forms a molded article having a bulge portion such as a tray of a compact disc storage case, which can be expanded and contracted and whose outer peripheral surface is a reverse taper surface. In addition, an object of the present invention is to ensure the release of the bulging portion in a die device in which the bulging portion is released from the die member forming the outer surface of the bulging portion by air blow.

[0007]

In order to achieve the above-mentioned object, the present invention comprises a plurality of projections arranged along a circumference,
A mold device for molding a molded article having a through groove between these protrusions and having a bulged portion whose outer peripheral surface has a reverse taper surface whose diameter gradually increases toward the tip, and which is a bulge in the molded article. First forming a back side including the inner surface of the protruding portion
And a second mold member that forms a front side including the outer surface of the bulge portion of the molded product, and a nest is embedded in the second mold member, and the molded product is formed around the nest. In a mold device for blowing air into the mold to release the bulging part of the molded product from the second mold member side, the convex part forming the through groove is provided on the second mold member side including the nest. It was installed in.

[0008]

In the mold apparatus of the present invention, a through groove is provided between a plurality of protrusions arranged along the circumference, and an outer peripheral surface is provided with a bulging portion having an inverse taper surface whose diameter gradually increases toward the tip. When molding a molded product, the back side including the inner surface of the bulged portion of the molded product is formed by the first mold member, and the front side of the molded product including the outer surface of the bulged portion is formed by the second mold member. To be done. Here, the reverse taper surface of the outer peripheral surface of the bulging portion is an undercut in the mold opening direction of the second mold member, but when the mold is opened, the molded product is separated from the first mold member side. After releasing the mold, when releasing from the second mold member side,
Air is blown to the molded product from the periphery of the nest embedded in the second mold member to elastically deform the bulged portion of the molded product and release it from the second mold member side. At this time, since the through groove is closed by the convex portion on the second mold member side including the nest until the molded product floats from the second mold member side by the thickness thereof, air does not leak, Air pressure is effectively applied to the molded product.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the mold apparatus of the present invention will be described below with reference to FIGS. The mold apparatus of this embodiment is for molding the tray 12 of the compact disc storage case as shown in FIGS. 4 and 5 described above. Reference numeral 61 is a fixed mold as a first mold member, and 62 is a movable mold as a second mold member. The fixed mold 61 and the movable mold 62 move vertically with respect to each other in the drawing to open and close to close the mold. Sometimes a cavity 63 in the shape of the tray 12 is formed inside. The fixed die 61 has a cavity member 64 that forms the back side of the tray 12 including the inner surface of the disc holding portion 31. On the other hand, the movable die 62 has a core member 65 forming the front side of the tray 12, and a nest 67 for air blow is formed in a through hole 66 formed through the core member 65 in the vertical direction in the drawing. Is embedded and fixed. The insert 67 forms the outer surface of the disk holding portion 31, and the cavity surface at the upper end of the insert 67 in the drawing is sized to include the entire through groove 33. Further, a concave groove-shaped air passage 68 is formed on the outer peripheral surface of the nest 67, and the compressed air is supplied to the air passage 68 via an air passage 69 formed in the core member 65 or the like. It is like this. Between the peripheral surface of the insert 67 and the peripheral surface of the through hole 66 of the core member 65, there are formed about four 0.02 mm gaps 70 from the air passage 68 to the cavity 63. Then, the protrusions 71 and 72 forming the through groove 33 of the disk holding portion 31 and the circular opening 34 thereof are formed in the nest 67.

Next, the operation of the above configuration will be described. Fixed mold 61 and movable mold 62 when molding the tray 12.
With the mold clamped, the molten resin is poured from the gate into the cavity 63 formed between the fixed mold 61 and the movable mold 62. Then, after the resin filled in the cavity 63 is solidified, the fixed die 61 and the movable die 62 are opened. At this time, first, the tray 12 is released from the fixed mold 61 side by the protrusion of the protruding pin on the fixed mold 61 side. Then, the movable type 62
The tray 12 is released from the movable mold 62 side by the protrusion of the protrusion pin on the side and the air blow. That is, as shown by the arrow in FIG. 1, air is blown from the air passages 68, 69 through the gap 70 between the peripheral surfaces of the nest 67 and the through hole 66 of the core member 65 to the central portion of the tray 12, The disc holding portion 31 elastically deforms and separates from the movable die 62. In this manner, the air blow blows out the disk holding portion 31 whose outer peripheral surface is an undercut reverse taper surface with respect to the die opening direction of the movable die 62. At this time, as shown in FIG. 1, the through-groove 33 and the circular opening 34 thereof are nested 67 until the tray 12 is lifted up from the movable die 62 by the thickness thereof.
Since it is closed by the convex portions 71 and 72, the space 73 formed between the cavity surface of the movable die 62 and the tray 12 is shielded from the outside air. Therefore, from the movable mold 42 to the tray
The air that flows into the space 73 from the gap 70 around the nest 67 and blows on the tray 12 does not escape to the outside air 74 until the 12 floats up by the thickness thereof, and the air pressure is effectively applied to the tray 12. As a result, the disc holding part is
31 can be reliably released from the mold.

The present invention is not limited to the above embodiment, and various modifications can be made. For example,
In the above-mentioned embodiment, the cavity 67 has a cavity surface having a through groove.
Although it has a large diameter including the whole 33, as shown in FIGS. 6 and 7, the nest 67 may have a small diameter forming only the central portion of the disc holding portion 31. In this case, the through groove 33 between the tips of the hook-shaped projections 32 and the convex portions 71 and 72 forming the circular opening 34 are formed in the nest 67, while the through groove 33 is formed.
The convex portion 76 that forms the remaining portion is formed on the core member 65. Further, in the above-mentioned embodiment, the case of forming the tray 12 of the compact disc storage case has been described as an example, but the present invention has the through groove between the plurality of protrusions arranged along the circumference, and the outer peripheral surface faces the tip. It can be generally applied to a molded article having a bulged portion having an inversely tapered surface whose diameter gradually increases.

[0012]

According to the present invention, like a tray of a compact disc storage case, it is provided with a bulging portion having a through groove between a plurality of protrusions arranged along the circumference and an outer peripheral surface having a reverse taper surface. In molding the molded product, a first mold member forming a back side including the inner surface of the bulging portion of the molded product and a second mold member forming a front side including the outer surface of the bulging portion are provided. In a mold apparatus in which a nest is embedded in the second mold member and air is blown from around the nest to the molded product to separate the bulging portion from the second mold member side, the through groove is formed. By providing the convex portion to be formed on the second mold member side including the nest, when the bulging portion is released from the mold by air blow, the molded product floats from the second mold member side by the thickness thereof. Until then, the through groove is blocked by the convex portion. In not leak air, the air pressure is applied to enable the molded article, therefore, it is possible to reliably release the bulging portion from the second mold member side.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a mold device of the present invention,
The state at the time of mold release is shown.

FIG. 2 is a cross-sectional view having a cross section taken along a plane passing through a protrusion of a disk holding portion that is a bulging portion.

FIG. 3 is a cross-sectional view showing a cross section of a surface passing through a through groove of the disc holding portion.

FIG. 4 is a perspective view of a compact disc storage case.

FIG. 5 is a perspective view of a tray of a compact disc storage case.

FIG. 6 is a cross-sectional view showing another embodiment of the mold apparatus of the present invention, in which the plane passing through the protrusion of the disc holding portion is taken as a cross section.

FIG. 7 is a cross-sectional view showing a cross section of a surface passing through a through groove of the disc holding portion.

FIG. 8 is a cross-sectional view showing an example of a conventional mold device, showing a state at the time of mold release.

FIG. 9 is a cross-sectional view of the same surface as the cross section passing through the protrusion of the disk holding portion.

FIG. 10 is a cross-sectional view of the same disk holding portion as a cross-section taken through a through groove.

[Explanation of symbols]

 12 Tray (molded product) 31 Disc holding part (bulging part) 32 Hook-shaped projection (projection) 33 Through groove 35 Reverse taper surface 61 Fixed mold (first mold member) 62 Movable mold (second mold member) ) 67 Nest 71 Convex 72 Convex 76 Convex

Claims (1)

[Claims] 1. A plurality of protrusions arranged along a circumference,
A mold device for molding a molded article having a through groove between these protrusions and having a bulged portion whose outer peripheral surface has a reverse taper surface whose diameter gradually increases toward the tip, and which is a bulge in the molded article. First forming a back side including the inner surface of the protruding portion
And a second mold member that forms a front side including the outer surface of the bulge portion of the molded product, and a nest is embedded in the second mold member, and the molded product is formed around the nest. In a mold device for blowing air into the mold to release the bulging part of the molded product from the second mold member side, the convex part forming the through groove is provided on the second mold member side including the nest. A mold device, which is provided in the.