JP2000281167A - Die for magnetic tape cassette storage case and magnetic tape cassette storage case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die for a magnetic tape cassette storage case having a good gas venting performance and a magnetic tape cassette storage case having a good external appearance which can be molded by means of the die. SOLUTION: In the magnetic tape cassette storing case 10, a first case having a flat plate 22 and a surrounding wall 23 and a second case having a flat plate and a surrounding wall are combined with each other, at least one of the surrounding walls of the first and second cases includes a wall 23 having a height of 6 mm or more. A die body 41 has cavities for forming ribs 26, 27 on its side surface to mold the inner side of the case 10. A molded item is pushed out of the body 41 by the forward end surfaces of ejector pine 43, 44 passing through the body 41. Before the item is pushed out, a gap S is formed between a molding surface of the body 41 and each of the forward end surfaces of the pins 43, 44 and the gap functions as a gas vent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape cassette storage case mold and a magnetic tape cassette storage case moldable with the mold.

[0002]

2. Description of the Related Art Recently, a small digital video camera with good portability has been used as a television camera dedicated to recording and recording. Even though this camera is small, since it can provide high image quality by digital signal processing, it is widely used as a professional equipment for broadcast station photographers, recording specialists, and the like.

[0003] There are various types of magnetic tape cassettes, and the one used by being loaded into the digital video camera is called a digital video cassette (DVC). DVC is available in three sizes with different recording times,
Each is sold in its own cassette storage case.

FIG. 3 shows an example of a conventionally used magnetic tape cassette storage case (DVC storage case). The storage case 80 includes a storage portion 81 in which the magnetic tape cassette M is stored, and a lid portion 91 connected to the storage portion 81 via a connecting piece 90 and a thin hinge 89. The storage section 81 has a plurality of mounting projections 87 and 88 corresponding to the concave shape of the magnetic tape cassette M on the inner surface (the upper surface in the figure).
, And side walls 83, 83 and an end wall 84, which stand in a frame shape around the bottom plate 82, and into which the magnetic tape cassette A is fitted. On the upper end and the outer surface of the side wall 83, a positioning notch 85 and a locking concave portion 86 are formed, respectively.

[0005] The lid 91 is erected on a top plate 92 and an inner surface of the top plate 92, that is, a surface facing the storage portion 81.
Side walls 93 and 93 and an end wall 94 that fit outside the side wall 83 and the end wall 84 of the storage section 81 are provided. On the inner surface of the side wall 93, a positioning rib 95 and a locking claw 96 are formed, respectively, which engage with the positioning notch 85 and the locking recess 86 of the storage portion 81, respectively. Also the side wall 93
A support rib 97 having an inclined surface 97a is formed on the inner surface of the. The support rib 97 supports the magnetic tape cassette M by its inclined surface 97a when the magnetic tape cassette M is stored in the storage section 81 and the lid 91 is closed.

The positioning rib 95 and the support rib 97 are
One end is in contact with the top plate 92 and extends along the side wall 93, but the locking claw 96 is provided on the distal end side of the side wall 93 and is not in contact with the top plate 92.

The storage case 80 is formed by injection molding or the like. The molding die includes a mold main body, that is, a movable mold for molding the inside of the storage case 80 and a fixed mold for molding the outside of the storage case 80. In addition, the mold has an undercut portion cavity on its side surface for forming an undercut portion such as the locking claw 96, and the ejector pin which is inclined while protruding the molded product from the movable mold by the tip surface. (Hereinafter, referred to as “inclined pin”), a slide core, and the like. When the inclined pin is inclined, the undercut portion is removed from the cavity on the side surface of the inclined pin.

[0008]

In the magnetic tape cassette storage case 80 or a magnetic tape cassette storage case similar to the case 80, the height of the side wall 93 and the end wall 94 of the lid 91 is a predetermined value. In the case of exceeding, there was a tendency that outgassing during molding was deteriorated. In particular, the height of the side wall 93 and the end wall 94 of the lid portion 91 depends on the resin material, the product shape, the gas vent width, and the gas vent installation position, but this tendency is remarkably observed when the height is 6 mm or more. Further, even when the height of the side wall 93 or the end wall 94 is less than 6 mm, poor gas release may occur.

If the gas escape is poor, air bubbles are trapped in the side wall 93 of the storage case, and the air bubbles deteriorate the appearance of the transparent magnetic tape cassette storage case made of polypropylene or the like. The present invention has been made in view of the above problems, and has as its object to provide a mold for a magnetic tape cassette storage case with good gas bleeding, and a magnetic tape cassette housing with a good appearance that can be molded by the mold. Is to provide a case.

As a result of intensive studies, the present inventors have found that the top plate 9 such as the positioning ribs 95 and the support ribs 97 in the lid 91 are provided.
2 and a rib extending along the side wall 93,
It has been found that if molding is performed by an ejector pin having a cavity for the rib on its own side surface, a small gap between the movable die and the ejector pin during molding can be used as a gas vent, and gas can be smoothly vented.

The present invention is constructed by combining a first case and a second case each having a flat plate and a peripheral wall, wherein at least one of the peripheral walls of the first case or the second case has a height of 6 mm or more. A magnetic tape cassette storage case mold for molding a magnetic tape cassette storage case including: a rib having a rib in contact with the flat plate and extending along the wall of the wall; Having a cavity for molding, the case is partially formed by an ejector pin projecting from the mold body by a tip end surface through a mold body for molding the inside of the case, and of the wall, the rib is not provided. Partially forming the wall with an ejector pin that protrudes the case from the mold main body with the tip end surface through the mold main body that forms the inside of the case. It is a symptom.

That is, the mold for a magnetic tape cassette storage case of the present invention is in contact with a top plate such as a positioning rib or a support rib in a lid portion of a side wall and an end wall having a height of 6 mm or more constituting a peripheral wall. In addition, a wall provided with a rib extending along the peripheral wall is partially formed by an ejector pin having a cavity for the rib on a side surface and projecting a case as a molded product by a tip end surface. Further, of the side wall and the end wall having a height of 6 mm or more, the wall not having the rib is partially formed by an ejector pin.

When the side wall and the end wall constituting the peripheral wall do not have the rib, a part of each wall is formed by an ejector pin. At this time, it is preferable to dispose the ejector pin in the vicinity of the location where the resin is finally filled in the cavity where the resin is filled, so that degassing can be performed more smoothly.

As the ejector pin, an inclined pin, an ejector pin for projecting a molded product in parallel with a moving direction of a mold main body (movable mold), or the like can be used. The gap between the mold main body and the ejector pin passing through the mold main body during molding is preferably 0.01 to 0.03 mm. If the gap is less than 0.01 mm, smooth protrusion cannot be performed, and if it exceeds 0.03 mm, burrs and the like are generated.

According to the magnetic tape cassette storage case mold having such a configuration, gas can be reliably released even when the magnetic tape cassette storage case having a peripheral wall having a height of 6 mm or more is formed. No air bubbles are trapped in the side walls or the like. Therefore, a magnetic tape cassette storage case having a good appearance can be obtained.

Further, the present invention is configured by combining a first case and a second case each having a flat plate and a peripheral wall, wherein at least one of the peripheral walls of the first case or the second case has a height of 6 mm or more. A magnetic tape cassette storage case including a wall, of the walls, a wall having a rib which is in contact with the flat plate and extends along the wall, a cavity for the rib on a side surface, and an inside of the case is provided. A mold that is partially formed by an ejector pin that protrudes the case from the mold main body by the tip end surface through the mold main body to be formed, and that, among the walls, the wall that does not have the rib is a mold that forms the inside of the case. The case is characterized in that the case is partially formed by an ejector pin that protrudes the case from the mold main body by the front end surface through the main body.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows the first embodiment of the present invention.
1 shows a magnetic tape cassette storage case according to an embodiment.
The storage case 10 includes a storage section 11 in which a magnetic tape cassette is stored, and a lid 21 connected to the storage section 11 via a connecting piece 20 and a thin hinge 19. The storage section 11 includes a rectangular bottom plate 12 having a plurality of mounting projections 17 and 18 on the inner surface thereof, and a side wall 1 which stands upright around the bottom plate 12 in a frame shape, and into which a magnetic tape cassette (not shown) is fitted.
3 and 13 and an end wall 14. The notch 15 for positioning and the concave portion 1 for locking
6 are formed respectively. A locking recess 16 is also provided on the central outer surface of the end wall 14.

The lid 21 has a top plate 22 hinged to the connecting piece 20 and side walls 23, 23 erected on the inner surface of the top plate 22 and fitted to the outside of the side wall 13 and the end wall 14 of the storage section 11.
And an end wall 24.

In a broadcasting station or the like, it is important that information such as contents recorded on a magnetic tape cassette and contents of a meeting at the recording site can be easily recognized later. In many cases, a piece of paper (hereinafter, referred to as "information sheet") P on which such information is written is sandwiched and stored. In the storage case 10 shown in FIG. 1, the height of the side wall 23 and the end wall 24 of the cover 21 and the width of the connecting piece 20 are set to the thickness of the magnetic tape cassette and the thickness of the information sheet P so that the information sheet P can be easily stored. And the sum of the storage thickness. Here, the height of the side wall 23 and the end wall 24 and the width of the connecting piece 20 are 20 mm (range of 15 to 30 mm).

On the inner surface of the side wall 23, there are formed a positioning rib 25 and a locking claw 26 which engage with the positioning notch 15 and the locking recess 16 of the storage portion 11, respectively. A locking claw 26 is also provided on the center inner surface of the end wall 24. At both ends of the end wall 24, support ribs 28 are provided for supporting the magnetic tape cassette when the magnetic tape cassette is stored in the storage section 11 and the lid 21 is closed. One end of the positioning rib 25 and the supporting rib 28 is in contact with the top plate 22 and extends along the side wall 23 and the end wall 24, respectively.
範 囲 20 mm).

Further, on the inner surface of the side wall 23, a paper holding rib 27 for holding the information paper P is provided. The paper holding rib 27 has a base end in contact with the top plate 22 and extends along the side wall 23, and a holding claw 27 b for holding an end of the information sheet P is provided at a tip end thereof. Holding claw 27
The upper surface of b is formed as an inclined surface 27a that supports the magnetic tape cassette when the magnetic tape cassette is stored in the storage section 11 and the lid 21 is closed. This paper holding rib 27
Becomes an undercut portion during molding.

The top plate 22 of the lid 21 is located near the bases of the positioning ribs 25 and the support ribs 28 and the top plate 2.
2 from the position where the locking claw 26 is provided.
In the vicinity of the point where the vertical line drawn toward the intersection intersects, a protrusion mark 30 is formed by the ejector pin. Also,
In the vicinity of the base of the paper holding rib 27, a protruding trace 31 having a dimension longer in the direction along the side wall 23 or the end wall 24 than the protruding trace 30 is formed.

FIG. 2 shows a magnetic tape cassette storage case mold according to a second embodiment of the present invention. The mold 40 is a mold main body, that is, a movable mold 4 for molding the inside of the storage case.
1 and a fixed mold (not shown) for molding the outside of the storage case
And The mold 40 has a cavity for the locking claw 26 on a side surface thereof in order to form the locking claw 26 which is an undercut portion. It is provided with an inclined pin 43 which is inclined inside the storage case. The base end of the inclined pin 43 is rotatably supported by a rotating shaft 45 provided on an ejector plate (not shown) and extending in a direction parallel to the side wall 23. FIG. 2 shows a state of the mold 40 before the protrusion. At this time, the tip of the inclined pin 43 and the movable mold 41 are shown.
A gap S is formed between the gap and the molding surface. Here, the gap S is 0.05 to 0.3 mm.

Also, the mold 40 has a cavity for the paper holding rib 27 on its own side for forming the paper holding rib 27 as an undercut portion, and the molded product is movable by the tip end surface. An inclined pin 44 is provided which is inclined in a direction along the side wall 23 while projecting from the 41. Inclined pin 44
Is rotatably supported by a rotating shaft 46 provided on an ejector plate (not shown) and perpendicular to the rotating shaft 45. Before projecting, tilt pin 4
Similarly to 3, a gap is formed between the tip surface of the inclined pin 44 and the molding surface of the movable die 41.

Although not shown, the mold 40 also includes the positioning ribs 25 and the support ribs 28 shown in FIG. 1, and the ejector pins for forming the locking claws 26 of the end wall 24. A gap is also formed between the distal end surfaces of these ejector pins and the molding surface of the movable die 41 before they protrude.

When the cavity of the mold 40 is filled with a synthetic resin, the gaps between the tip surfaces of the inclined pins 43 and 44 and the movable mold 41, the positioning ribs 25, the support ribs 28 and the end walls are provided. The gap between the tip surface of each ejector pin for forming the locking claw 24 and the molding surface of the movable die 41 functions as a gas vent.

Thereafter, when the ejector plate (not shown) is driven from the state shown in FIG. 2 and the storage case 10 as a molded product is protruded from the movable mold 41 by the inclination pins 43 and 44, the inclination pin 43 is moved inside the storage case. That is, the inclination pin 44 is inclined in the direction perpendicular to the side wall 23, and the inclination pin 44 is inclined in the direction along the side wall 23. Thereby, the locking claw 26 and the paper holding rib 27, which are the undercut portions, are pulled out of the cavities on the side surfaces of the inclined pins 43 and 44, respectively.

In the magnetic tape cassette housing case mold 40 having the above-described structure, the positioning ribs 25, the support ribs 28, and the paper are formed so that one end thereof is in contact with the top plate 22 and extends along the side wall 23 and the end wall 24, respectively. The holding rib 27 is formed by an ejector pin and an inclined pin 44, and a gap between the pin and the movable mold 41 is used as a gas vent, so that gas is reliably vented. Therefore, no air bubbles are trapped in the side wall 23 and the end wall 24, and a magnetic tape cassette storage case having a good appearance can be formed.

Further, all the undercut portions such as the locking claws 26 are formed by the inclined pins 43 or the ejector pins.
Since the gap between the pins and the movable mold 41 is used as a gas vent, more favorable gas release can be performed.

Further, the present invention is not limited to the above-described embodiment, and appropriate modifications and changes can be made.
For example, the storage part is in contact with the bottom plate inside and 6m
A magnetic tape cassette storage case having a rib extending along a peripheral wall having a height of not less than m can be formed by the mold of the present invention. Alternatively, the molded product may remain in the fixed mold, and the molded product may be protruded by an ejector pin passing through the fixed mold.

[0031]

As described above, according to the mold for a magnetic tape cassette storage case of the present invention, gas is reliably released even when a magnetic tape cassette storage case having a peripheral wall having a height of 6 mm or more is formed. Air bubbles are not trapped in the side wall of the storage case. Therefore, a magnetic tape cassette storage case having a good appearance can be obtained. In particular, this mold is suitable for molding a transparent magnetic tape cassette storage case made of PP or the like. In addition, the magnetic tape cassette storage case of the present invention has a very good appearance because the air bubbles are not trapped in the side walls and the like and are arranged on the periphery of the flat plate where protrusion marks are relatively inconspicuous.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a partially enlarged perspective view showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a conventional magnetic tape cassette storage case.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Magnetic tape cassette storage case 11 Storage part (2nd case) 12 Bottom plate (2nd flat plate) 13 Side wall (2nd peripheral wall) 14 End wall (2nd peripheral wall) 15 Notch for positioning 16 Locking recess 19 Thin hinge 20 Connecting piece 21 Lid (first case) 22 Top plate (first flat plate) 23 Side wall (second peripheral wall) 24 End wall (second peripheral wall) 25 Positioning rib 26 Locking claw 27 Paper holding rib 28 Support rib 30,31 protruding trace

Claims (2)

[Claims] 1. A first case and a second case each having a flat plate and a peripheral wall are combined, and at least one of the peripheral walls of the first case and the second case includes a wall having a height of 6 mm or more. A magnetic tape cassette storage case mold for molding a magnetic tape cassette storage case, wherein a wall having a rib that is in contact with the flat plate and extends along the wall is provided on the side surface of the mold. It has a cavity and is partially formed by an ejector pin that projects the case out of the mold main body with a tip end surface through a mold main body that forms the inside of the case, and among the walls, the wall that does not have the rib is formed. A case in which the case is partially formed by an ejector pin projecting from the mold body by a tip end surface through a mold body for molding the inside of the case. Magnetic tape cassette storage case mold. 2. A combination of a first case and a second case having a flat plate and a peripheral wall, wherein at least one of the peripheral walls of the first case and the second case includes a wall having a height of 6 mm or more. A magnetic tape cassette storage case, comprising: a wall having a rib in contact with the flat plate and extending along the wall; and a side wall having a cavity for the rib, and a metal for forming an inside of the case. The case is partially formed by an ejector pin that protrudes the case from the mold main body by the tip end surface through the mold main body, and among the walls, the wall having no rib passes through the mold main body that forms the inside of the case. A magnetic tape cassette storage case, wherein the case is partially formed by an ejector pin that projects the case from a mold main body by a tip end surface.