JP2569117Y2 - Guard panel for VTR cassette tape and mold for molding the same - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guard panel for a VTR cassette tape and a mold for molding the guard panel.

[0002]

2. Description of the Related Art As shown in FIG. 5, a guard panel 4 for protecting an exposed portion of a tape 3 is provided on a front surface of a cassette 2 of a VTR cassette tape 1 so as to be freely opened and closed. The guard panel 4 is shown in FIG. 4 as a so-called clawless type.
The surface portion 7 is bent substantially vertically rearward, and has a substantially L-shaped cross section. The width of the first surface portion 6 is larger than the width of the second surface portion 7. In addition, the guard panel 4 is bent substantially vertically downward from the first surface 6 rearward and substantially vertically downward from the second surface 7, and has third surface portions 8, 9 at the left and right ends of the guard panel 4.
Are formed respectively. These third surface portions 8 and 9
It extends to the rear from the second surface 7. Shafts 10 and 11 for pivotally attaching the guard panel 4 to the cassette 2 are formed on the inner surfaces of the rear ends of the third surfaces 8 and 9. As shown in FIG. 6, a ridge 12 is formed on the lower edge of the inner surface of the first surface portion 6. Note that the upper surface of the ridge 12 is inclined in a direction to rise toward the outer surface of the first surface portion 6. In addition, on the inner surfaces of both the third surface portions 8 and 9,
As shown in FIG. 10, trapezoidal projections 13 are formed. That is, the side surface of the convex portion 13 is an inclined surface that forms an obtuse angle with respect to the inner surfaces of the third surface portions 8 and 9.
Further, in the guard panel 4 shown in FIG. 4, the outer surfaces of the first surface portion 6 and the second surface portion 7 have a grained surface 14 as shown in FIG. The other surfaces are mirrored.

Incidentally, the guard panel is generally an integrally molded product of resin. Here, an example of a conventional molding die for the guard panel 4 will be described with reference to FIGS. 6 to 9. In the following description, the vertical direction in the drawing is the vertical direction. This mold has an upper fixed mold 21 as a first mold member and a lower movable mold as a second mold member.
And 22. These fixed mold 21 and movable mold 22
They move up and down to open and close each other, and form a cavity in the shape of the guard panel 4 therebetween when the mold is closed. The fixed mold 21 forms an outer surface of the guard panel 4, and the movable mold 22 forms an inner surface of the guard panel 4. And the fixed mold 21 and the movable mold
The opening / closing direction of 22 is a direction parallel to the third surface portions 8, 9;
Further, the direction is substantially perpendicular to the second surface portion 7 and is along the first surface portion 6, but is inclined at an angle θ with respect to the first surface portion 6 so that the outer surface thereof is slightly upward. doing. Is about 5 to 15 degrees. In addition, fixed type
One purpose of setting the opening and closing directions of the movable mold 21 and the movable mold 22 to be substantially orthogonal to the second surface 7 is that the guard panel 4 can be formed by a single fixed mold 21 and a movable mold 22 without using a slide core. To do that. Therefore, with respect to the inner surfaces of the third surface portions 8 and 9, the extension surfaces of the parting line surfaces of the fixed die 21 and the movable die 22 are formed by the shaft portions 10 and 11.
Through the central axis of Also, as shown in FIG.
The grain on the outer surface of the face portion 6 and the outer face of the second face portion 7 is formed by subjecting the cavity wall itself of the fixed mold 21 to graining. However, as described above, the mold opening / closing direction is inclined at an angle θ. This is also to reduce the release resistance due to the grain. The first surface portion 6 has a ridge 12 on the inner surface, and the third surface portions 8 and 9 have a ridge 13 on the inner surface. The upper side of the ridge 12 and the protrusion 13 is in the mold opening direction of the movable mold 22. Has an undercut shape. That is, on the cavity wall of the movable mold 22, the concave ridges 23 for forming the convex ridges 12 and the convex portions 13 are formed.
And a concave portion 24 are formed, and the upper surfaces of the concave streak 23 and the concave portion 24 are located closer to the fixed mold 21 than the cavity in the mold opening and closing direction. In addition, the upper surfaces of the concave stripes 23 and the concave parts 24 are inclined so that the mold can be released. In addition, a plurality of protrusion pins 25 as protrusion members are incorporated in the movable mold 22 so as to be vertically slidable. The protruding pins 25 have their upper ends located on the inner surface of the second surface portion 7. On the other hand, the fixed die 21 has a gate 27 with a built-in spear 26 formed therein. This gate
Reference numeral 27 denotes an opening at a position where the outer surface of the second surface portion 7 in the cavity wall is formed, and there is only one for one cavity.

In molding, first, as shown in FIGS. 6 and 8, the fixed mold 21 and the movable mold 22 are closed, and
A cavity having the shape of the guard panel 4 is formed between the fixed mold 21 and the movable mold 22. In this state, gate 26
The molten resin is injected into the cavity from. After the resin filled in the cavity is sufficiently cooled and solidified, the fixed mold 21 and the movable mold 22 are opened as shown by a chain line in FIG. At this time, the formed guard panel 4 first stops on the movable mold 22 side and separates from the fixed mold 21. In particular, the grain on the outer surface of the first surface portion 6 is resistant to release from the fixed mold 21, but the ridge 12 of the first surface portion 6 and the third surface portion 8,
9 due to the release resistance caused by the protrusion 13 of the guard panel 4.
Stops on the movable mold 22 side. Then, after the fixed mold 21 is sufficiently separated from the guard panel 4, the protruding pins 25 start to move upward with respect to the movable mold 22, and are protruded by the protruding pins 25, so that the guard panel 4 is separated from the movable mold 22. At this time, the first surface portion 6 and the third surface portions 8 and 9 are elastically deformed outward, so that the ridges 12 and the protrusions 13 of the guard panel 4 are formed.
Moves over the positions above the concave strips 23 and the concave sections 24 in the movable mold 22. That is, the ridges 12 and the ridges 13 of the guard panel 4 are forcibly removed. In this state, the card panel 4
Is taken out.

[0005]

However, the conventional guard panel mold has the following problems. That is, as described above, in particular, the grain on the outer surface of the first surface portion 6 becomes a resistance against the release from the fixed mold 21, so that at the start of the mold opening, the guard panel 4 tries to follow the fixed mold 21. On the other hand, the first surface portion 6 and the third surface portion 8,
The undercut shapes of the ridges 12 and the protrusions 9 act to stop the guard panel 4 on the movable mold 22. However, even if the ridges 12 and the protrusions 13 as described above are simply provided, the mold opening is started. Time,
It may not be possible to reliably prevent the guard panel 4 from following the fixed mold 21. If the guard panel 4 is attached to the fixed mold 21, the formed guard panel 4 cannot be taken out smoothly. The guard panel 4 is movable.
If the guard panel 4 once floats toward the fixed mold 21 at the start of the mold opening even when stopping on the 22 side, the grained surface 14 of the guard panel 4 and the corresponding grained surface 28 of the fixed mold 21 rub against each other,
The grained surface 14 of the guard panel 4 is damaged.

On the other hand, at the start of the mold opening, one means for securely stopping the guard panel 4 on the movable mold 22 side is the ridge 12
In other words, the undercut amount of the projection 13 or the protrusion amount is increased. However, there is a limit in increasing the amount of protrusion of the ridges 12 and the ridges 13 due to product specifications.

In order to save resin material, it is preferable to make the guard panel 4 thinner. First surface 6 and second surface 7
Although there is no problem even if it is thin, the guard panel 4
When the entire surface is thinned, the third surface portions 8 and 9 perpendicular to the direction of the rotation axis of the first and second surfaces create a gap between the third surface portions 8 and 9 and the corresponding side surface of the cassette 2, thereby causing backlash of the guard panel 4 with respect to the cassette 2. Become. Therefore, if only the first surface portion 6 and the second surface portion 7 are made thin and the entire third surface portions 8 and 9 are made thicker in order to prevent this rattling, a difference in thickness occurs at the time of molding. As a result, there is a time difference in the shrinkage due to cooling between the first surface portion 6 and the second surface portion 7 and the third surface portions 8 and 9, so that the third surface portions 8 and 9 fall down. This falling causes the formed guard panel 4 to deviate from the specified dimensions, and also hinders the release of the guard panel 4 from the mold.

The present invention is intended to solve such a problem. The third panel of the guard panel is made thinner without causing backlash of the guard panel with respect to the cassette, and shrinkage during molding is caused. Also prevents the third surface from falling down,
Further, it is another object of the present invention to ensure that mold release during molding is ensured.

[0009]

SUMMARY OF THE INVENTION The present invention is intended to achieve the above object, and the invention of claim 1 is an elongated first surface portion and a second surface portion which are connected at one edge along the longitudinal direction and are substantially orthogonal to each other. And a pair of third surface portions substantially perpendicular to the first surface portion and the second surface portion in a form bent from both end edges along the lateral direction of the first surface portion and the second surface portion, and are integrally formed of resin. In the VTR cassette tape guard panel, a concave portion is formed on the inner surface of the third surface portion so as to be located away from the edge thereof.

In a second aspect of the present invention, a guard panel for the VTR cassette tape is formed, and a first mold member forming an outer surface of the guard panel,
A second mold member that opens and closes with respect to the mold member and forms an inner surface of the guard panel; and a guard panel provided on the second mold member side and molded from the second mold member side. A projecting member for releasing the mold, wherein the opening and closing directions of the two mold members are substantially parallel to the third surface portion.
A convex portion forming the concave portion of the guard panel is formed on a surface forming the surface portion.

[0011]

The guard panel for a VTR cassette tape according to the first aspect of the present invention is formed by forming recesses on the inner surface of the third surface at both ends in the longitudinal direction, the recesses being located away from the edge.
The third surface is made thinner by the amount of the recess. Also,
When the guard panel is assembled to the cassette, a gap is formed between the side surface of the cassette and the third surface portion to prevent rattling when the guard panel is assembled to the cassette.
Further, by making the third surface portion thinner as described above in addition to the first surface portion and the second surface portion, it is possible to prevent the third surface portion from falling down due to shrinkage when the guard panel is formed of resin.

Further, in the mold for molding a guard panel for a VTR cassette tape according to the present invention, the first mold member and the second mold member are closed during molding, and these molds are closed. A cavity is formed between the members, and the cavity is filled with a resin. Thus, the guard panel has an outer surface formed by the first mold member and an inner surface formed by the second mold member. In particular, the concave portion of the inner surface of the third surface portion is formed by the second mold member.
Formed by the convex portion of the mold member. After that, open both mold members and take out the molded guard panel,
When mold opening begins, the guard panel first stops at the second mold member and moves away from the first mold member. The mold opening and closing direction is
The underside of the concave portion, which is in a direction substantially parallel to the third surface portion but is located on the inner surface of the third surface portion and separated from the edge, has an undercut shape with respect to the mold opening direction of the second mold member. Therefore, the guard panel is prevented from following the first mold member. In addition, since the recess can increase the amount of undercut, even if the release resistance of the first mold member is large, the guard panel is reliably prevented from following the first mold member. Then, after the first mold member is sufficiently separated from the second mold member, the projecting member projects the guard panel to release the guard panel from the second mold member. At this time, while the third surface portion is elastically deformed outward,
The concave portion of the guard panel is forcibly removed from the convex portion of the second mold member.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. The guard panel 4 for a VTR cassette tape and the mold for molding the same according to the present embodiment have substantially the same configuration as the guard panel 4 and the mold for molding the conventional guard panel 4 shown in FIGS. 4 to 7 described above. Therefore, the corresponding portions are denoted by the same reference numerals, description thereof will be omitted, and different points will be mainly described. Further, in the following description, reference numerals given to FIGS. 4 to 7 are also cited. First, regarding the guard panel 4, concave portions 31 are formed on the inner surfaces of the third surface portions 8, 9 at both ends instead of the conventional convex portions. The concave portion 31 extends over a wide area except for the peripheral portions of the third surface portions 8 and 9, but does not extend to the edges of the third surface portions 8 and 9.

On the other hand, in the molding die, the guard panel 4 is provided with the guard panel 4 on the surface on which the third surface portions 8 and 9 are formed in the movable die 22 which is the second die member. A trapezoidal convex part 32 forming the four concave parts 31 is formed. The lower surface of the convex portion 32 is located closer to the fixed mold 21 as the first mold member than the cavity, and
Has an undercut shape with respect to the mold opening direction. In addition, the surrounding side surfaces including the lower surface of the convex portion 32 are inclined so that the mold can be released.

Next, a molding method using this mold will be described. At the time of molding, as shown by a solid line in FIG. 1, after the resin filled in the cavity formed between the fixed mold 21 and the movable mold 22 which have been closed is sufficiently cooled and solidified, as shown by a chain line in FIG. Then, the fixed mold 21 and the movable mold 22 are opened. At this time, the formed guard panel 4 first stops on the movable mold 22 side and separates from the fixed mold 21. In particular, the grain on the outer surface of the first surface portion 6 is resistant to release from the fixed mold 21, but the ridges 12 of the first surface portion 6 and the concave portions 31 of the third surface portions 8 and 9 are provided.
The guard panel 4 is movable 22 by the release resistance caused by
Stop on the side. Then, after the fixed mold 21 is sufficiently separated from the guard panel 4, the protruding pins 25 start to move upward with respect to the movable mold 22, and are protruded by the protruding pins 25, so that the guard panel 4 is separated from the movable mold 22. At this time, the lower part of the recess 31 of the third surface portions 8 and 9 of the guard panel 4
The surface portions 8 and 9 are elastically deformed outwardly to get over the convex portions 32 of the movable mold 22 forming the concave portions 31. That is, the recess 31 of the guard panel 4 is forcibly removed.

As described above, the guard panel 4 is stopped by the movable mold 22 at the start of mold opening due to the undercut shapes of the ridges 12 and the recesses 31. In particular, the third face portions 8, 9 are provided.
The concave portion 31 can have a larger amount of undercut, that is, a depth, than the conventional convex portion, and has a large area of the third surface portions 8 and 9. A resistance is given, and the guard panel 4 can be reliably prevented from following the fixed mold 21 at the start of mold opening. This can prevent the outer surface of the guard panel 4 from being damaged.

Further, the third portion of the guard panel 4 corresponds to the concave portion 31.
The surface portions 8 and 9 can be made thin. Nevertheless, since a thick portion is left around the inner surfaces of the third surface portions 8 and 9, it is possible to secure a thickness necessary for assembling into the cassette 2 in this portion. That is, when the guard panel 4 is incorporated in the cassette 2, a large gap does not occur between the side surface of the cassette 2 and the third surface portions 8, 9. Thereby, the backlash of the guard panel 4 with respect to the cassette 2 is also prevented. Furthermore, in addition to the first surface portion 6 and the second surface portion 7, the third surface portions 8, 9 are made as thin as the concave portions 31 so that the third surface portions 8, 9 fall down due to shrinkage of the resin during molding. Can be prevented. Thus, it is possible to provide the guard panel 4 that can save material and is excellent in accuracy and moldability.

The present invention is not limited to the above embodiment, and various modifications can be made. For example,
The shape and size of the concave portion formed on the inner surface of the third surface portion of the guard panel are not limited to those of the above-described embodiment, and for example, each third
A plurality of small concave portions may be formed on the inner surface of the surface.

[0019]

According to the first aspect of the present invention, in the guard panel for a VTR cassette tape, a concave portion is formed on the inner surface of the third surface portion at both ends in the longitudinal direction, the concave portion being located away from the end edge. The thick portion at least at the peripheral portion of the surface portion prevents a gap from being formed between the side surface of the cassette and the third surface portion when the cassette is assembled to the cassette so that the guard panel rattles against the cassette. While preventing, the third surface portion can be made thinner by the amount of the concave portion. Thereby, in addition to the other first surface portion and second surface portion of the guard panel, the third surface portion can be made as thin as possible, and therefore,
When the guard panel is formed, the third surface portion can be prevented from falling down due to the contraction of the resin. In this way, it is possible to provide a guard panel that can save material and is excellent in accuracy and moldability.

Further, according to the invention of claim 2, a first mold member forming the outer surface of the guard panel and a second mold member forming the inner surface of the guard panel are provided. In a molding die in which the opening / closing direction of the member is substantially parallel to the third surface of the guard panel, the concave portion of the guard panel is formed on a surface of the second mold member that forms the third surface. Since the convex portion is formed, the concave portion and the convex portion have an undercut shape with respect to the mold opening direction of the second mold member, but the relationship between the irregularities is opposite between the guard panel side and the mold side. Can increase the amount of undercut, so that even when the release resistance of the first mold member is large at the start of mold opening, the molded guard panel must first stop at the second mold member. About the mold parts The can be reliably prevented. This can prevent the outer surface of the guard panel from being damaged.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a guard panel molding die of the present invention in a mold closed state.

FIG. 2 is a vertical cross-sectional view of the same mold open state.

FIG. 3 is a perspective view of a part of the guard panel formed as above.

FIG. 4 is a perspective view of the entire guard panel.

FIG. 5 is a perspective view of a VTR cassette tape incorporating the guard panel.

FIG. 6 is a cross-sectional view showing an example of a conventional guard panel molding die.

FIG. 7 is an enlarged view of a portion indicated by A in FIG.

FIG. 8 is a longitudinal sectional view of the same mold closed state.

FIG. 9 is a longitudinal sectional view of the same mold open state.

FIG. 10 is a perspective view of a part of the guard panel molded as above.

[Explanation of symbols]

 Reference Signs List 4 Guard panel 6 First surface 7 Second surface 8 Third surface 9 Third surface 21 Fixed die (first die member) 22 Movable die (second die member) 25 Projection pin (projection member) 31 Depression 32 convex

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G11B 23/113 510 G11B 23/113 510Q // B29L 31:34

Claims (2)

(57) [Scope of request for utility model registration] An elongated first surface and a second surface which are connected at one edge along the longitudinal direction and are substantially orthogonal to each other, and the first and second surfaces are bent from both end edges along the short direction of the first and second surfaces. A guard panel for a VTR cassette tape having a pair of third surface portions substantially orthogonal to a surface portion and a second surface portion and integrally formed of resin, wherein a concave portion located on the inner surface of the third surface portion and separated from an edge thereof. A guard panel for a VTR cassette tape, wherein a guard panel is formed. 2. A VTR cassette tape guard panel according to claim 1, wherein the first mold member forms an outer surface of the guard panel, and the first mold member is opened and closed with respect to the first mold member. A second mold member forming an inner surface of the guard panel; and a protruding member provided on the second mold member side and releasing the guard panel molded from the second mold member side. In a molding die in which the opening and closing directions of the two mold members are substantially parallel to the third surface portion, the guard panel is provided on a surface forming the third surface portion of the second mold member. A mold for molding a guard panel for a VTR cassette tape, wherein a convex portion forming a concave portion is formed.