JPH0684579U - Guard panel for VTR cassette tape and mold for molding the same - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the thickness of the third surface at both ends of the guard panel without rattling the cassette. Prevents molding defects and mold release defects. [Structure] A concave portion 31 is formed on the inner surface of the third surface portion 8 of the guard panel 4.
To form. In molding, the guard panel 4 by the fixed mold 21
The outer surface is formed, and the inner surface is formed by the movable die 22. The fixed die 21 and the movable die 22 are opened and closed in a direction parallel to the third surface portion 8. The movable die 22 has a convex portion 32 forming a concave portion 31. [Effect] The third surface portion 8 can be thinned by the amount of the recess 31. The thick portion in the peripheral portion of the third surface portion 8 prevents rattling of the cassette. The third surface portion 8 is thinned to the same extent as the first surface portion 6 and the second surface portion 7, and the third surface portion 8 is thinned by resin shrinkage during molding.
It is possible to prevent the face portion 8 from falling down. When the mold opening is started, the undercut shape of the recess 31 ensures that the guard panel 4 can be moved.
Stopped at 22.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a VTR cassette tape guard panel and a mold for molding the same.

[0002]

[Prior art]

 As shown in FIG. 5, on the front surface of the cassette 2 of the VTR cassette tape 1, a guard panel 4 for protecting the exposed portion of the tape 3 is provided so as to be openable and closable. This guard panel 4 is shown as a so-called clawless type in FIG. 4, but the second surface portion 7 is bent substantially vertically rearward from the upper edge of the first surface portion 6 elongated to the left and right, and has a substantially L-shaped cross section. It has become. The width of the first surface portion 6 is larger than the width of the second surface portion 7. In addition, the third surface portions 8 and 9 are formed at the left and right ends of the guard panel 4 in such a manner that they are bent substantially vertically rearward from the first surface portion 6 and are bent substantially vertically downward from the second surface portion 7, respectively. Has been. These third surface portions 8 and 9 extend rearward of the second surface portion 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 end portions of the third surface portions 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. The upper surface of the ridge 12 is inclined in the direction of rising toward the outer surface of the first surface portion 6. Further, as shown in FIG. 10, trapezoidal convex portions 13 are formed on the inner surfaces of the third surface portions 8 and 9, respectively. That is, the side surface of the convex portion 13 is an inclined surface that forms an obtuse angle with 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 grain surface 14 as shown in FIG. The other surfaces are mirror surfaces.

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 figure will be referred to as the vertical direction. This mold has an upper fixed mold 21 which is a first mold member and a lower movable mold 22 which is a second mold member. The fixed mold 21 and the movable mold 22 move in the vertical direction to open and close each other, and when the molds are closed, a cavity having the shape of the guard panel 4 is formed between them. The fixed mold 21 forms the outer surface of the guard panel 4, and the movable mold 22 forms the inner surface of the guard panel 4. The opening and closing directions of the fixed die 21 and the movable die 22 are parallel to the third surface portions 8 and 9, and are substantially orthogonal to the second surface portion 7 and along the first surface portion 6. However, the outer surface of the first surface portion 6 is inclined at an angle θ so that the outer surface thereof is slightly upward. This θ is about 5 to 15 °. One purpose of making the opening and closing directions of the fixed mold 21 and the movable mold 22 substantially orthogonal to the second surface portion 7 is to use the guard panel 4 as a single fixed mold 21 and movable mold without using the slide core. This is because it is possible to mold with 22. Therefore, with respect to the inner surfaces of the third surface portions 8 and 9, the extended surfaces of the parting line surfaces of the fixed die 21 and the movable die 22 pass through the central axes of the shaft portions 10 and 11. Further, as shown in FIG. 7, the crevices on the outer surfaces of the first surface portion 6 and the second surface portion 7 are formed by subjecting the cavity wall of the fixed die 21 itself to grain processing. The reason that the opening and closing direction is inclined at the angle θ is also to reduce the release resistance due to the grain. In addition, there is a convex strip 12 on the inner surface of the first surface portion 6 and a convex portion 13 on the inner surface of the third surface portions 8 and 9. It has an undercut shape. That is, the cavity wall of the movable die 22 is formed with the concave ridges 23 and the concave portions 24 for forming the convex ridges 12 and the convex portions 13, and the upper surfaces of the concave ridges 23 and the concave portions 24 are It is located closer to the fixed mold 21 side than the cavity in the opening / closing direction. The upper surfaces of the concave line 23 and the concave portion 24 are inclined so that the mold can be released. In addition, a plurality of ejecting pins 25 as ejecting members are incorporated in the movable die 22 so as to be vertically slidable. The upper ends of the protrusion pins 25 are located on the inner surface of the second surface portion 7. On the other hand, the fixed mold 21 is formed with a gate 27 containing a spear 26. The gate 27 is open to a position forming an outer surface of the second surface portion 7 on the cavity wall, and only one gate 27 is provided 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 the guard panel 4 is inserted between the fixed mold 21 and the movable mold 22. Form a shaped cavity. In this state, molten resin is injected from the gate 26 into the cavity. Then, 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 molded guard panel 4 first stops on the movable die 22 side and separates from the fixed die 21. In particular, the crevices on the outer surface of the first surface portion 6 resist the release from the fixed die 21, but the ridges 12 of the first surface portion 6 and the protrusions 13 of the third surface portions 8 and 9 cause the separation. Due to the mold resistance, the guard panel 4 stops on the movable mold 22 side. Then, after the fixed die 21 is sufficiently separated from the guard panel 4, the ejection pins 25 start to rise with respect to the movable die 22 and are ejected by these ejection pins 25, so that the guard panel 4 is separated from the movable die 22. At this time, the first surface portion 6 and the third surface portions 8 and 9 are elastically deformed outward, so that the protrusions 12 and 13 of the guard panel 4 are positioned above the recesses 23 and the recesses 24 of the movable die 22. get over. That is, the ridge 12 and the ridge 13 of the guard panel 4 are forcibly removed. In this state, the card panel 4 is taken out.

[0005]

[Problems to be solved by the device]

 However, the conventional guard panel molding die has the following problems. That is, as described above, in particular, since the outer surface of the first surface portion 6 becomes a resistance against the mold release from the fixed mold 21, the guard panel 4 tries to follow the fixed mold 21 at the start of mold opening. . On the other hand, the undercut shapes of the protrusions 12 and the protrusions 13 of the first surface portion 6 and the third surface portions 8 and 9 act so as to stop the guard panel 4 on the movable die 22, but as described above. Even if the convex ridges 12 and the convex portions 13 are provided, it may not be possible to reliably prevent the guard panel 4 from following the fixed mold 21 at the start of mold opening. If the guard panel 4 is attached to the fixed mold 21, the molded guard panel 4 cannot be taken out smoothly. Even if the guard panel 4 stops on the movable die 22 side, if the guard panel 4 temporarily floats toward the fixed die 21 at the start of die opening, the crease surface 14 of the guard panel 4 corresponds to the fixed die 21. The grain surface 28 and the grain surface 14 rub against each other, and the grain surface 14 of the guard panel 4 is damaged.

On the other hand, one means for securely stopping the guard panel 4 on the movable die 22 side at the start of mold opening is to increase the undercut amount, that is, the protruding amount of the ridges 12 and the protrusions 13. is there. However, there is a limit in increasing the amount of protrusion of the ridges 12 and the protrusions 13 according to the product standard.

In order to save the resin material, it is preferable to make the guard panel 4 thin. Even if the first surface portion 6 and the second surface portion 7 are made thin, there is no problem, but the third surface portions 8 and 9 orthogonal to the rotation axis direction of the guard panel 4 are compatible with the cassette 2 when they are made thin. By forming a gap between the side wall and the side surface, the guard panel 4 rattles with respect to the cassette 2. Therefore, in order to prevent the rattling, if only the first surface portion 6 and the second surface portion 7 are thinned and the third surface portions 8 and 9 are kept thick as a whole, the difference in thickness during molding may occur. Then, the first surface portion 6 and the second surface portion 7 and the third surface portions 8 and 9 have a time difference in contraction due to cooling, so that the third surface portions 8 and 9 collapse. This collapse causes the molded guard panel 4 to deviate from the specified dimension and hinders the release of the guard panel 4.

The present invention is intended to solve such a problem and thins the third surface portion of the guard panel without causing rattling of the guard panel with respect to the cassette, resulting in shrinkage during molding. The purpose of the present invention is to prevent the third surface part from collapsing, and also to ensure mold release during molding.

[0009]

[Means for Solving the Problems]

 The present invention is intended to achieve the above object, and the invention of claim 1 is directed to an elongated first surface portion and a second surface portion which are connected to each other at one end along the longitudinal direction and are substantially orthogonal to each other, and the first surface portion and the second surface portion. In a guard panel for a VTR cassette tape, which is integrally molded with resin, has a first surface and a pair of third surfaces that are substantially orthogonal to the second surface and is bent from both edges along the widthwise direction of the second surface. The inner surface of the third surface portion is provided with a recessed portion located away from the end edge thereof.

Further, the invention of claim 2 is to mold the guard panel for the VTR cassette tape, the first mold member forming an outer surface of the guard panel, and the first mold member. A second mold member that opens and closes the guard panel to form the inner surface of the guard panel, and a protruding member that is provided on the second mold member side and that releases the molded guard panel from the second mold member side. A molding die in which the opening and closing directions of the two die members are substantially parallel to the third surface portion, the surface forming the third surface portion of the second die member, It is formed by forming a convex portion that forms the concave portion of the guard panel.

[0011]

[Action]

 The guard panel for a VTR cassette tape according to the first aspect of the present invention is characterized in that by forming a concave portion located away from the end edge on the inner surface of the third surface portion at both ends in the longitudinal direction, the third surface portion is formed by the amount of the concave portion. Is a thin. Further, the thick portion around the concave portion prevents a rattling due to a gap between the side surface of the cassette and the third surface portion when the guard panel is assembled to the cassette. Further, in addition to the first surface portion and the second surface portion, by thinning the third surface portion as described above, it is possible to prevent the third surface portion from collapsing due to shrinkage when the guard panel is molded with resin. It

In the mold for molding the guard panel for a VTR cassette tape according to the second aspect of the 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 mold members, and resin is filled in the cavity. Thus, in the guard panel, the outer surface is formed by the first mold member and the inner surface is formed by the second mold member, and in particular, the concave portion on the inner surface of the third surface portion is the convex portion of the second mold member. It is formed by parts. After that, both mold members are opened, and the molded guard panel is taken out. When the mold opening is started, the guard panel first stops at the second mold member and separates from the first mold member. . The mold opening / closing direction is a direction substantially parallel to the third surface portion, but the lower side of the concave portion located on the inner surface of the third surface portion and located away from the edge thereof is in the mold opening direction of the second mold member. On the other hand, the undercut shape prevents the guard panel from following the first mold member. Moreover, since the undercut amount of the concave portion can be increased, even if the mold release resistance of the first mold member is large, it is possible to reliably prevent the guard panel from following the first mold member. After that, after the first mold member is sufficiently separated from the second mold member, the protrusion member protrudes the guard panel to release from the second mold member. At this time, the concave portion of the guard panel is forcibly removed from the convex portion of the second mold member while the third surface portion is elastically deformed outward.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. The VTR cassette tape guard panel 4 and its molding die of this embodiment have substantially the same structure as the conventional guard panel 4 and its molding die shown in FIGS. 4 to 7 described above. Therefore, the corresponding parts will be denoted by the same reference numerals, and the description thereof will be omitted. Differences will be mainly described. Further, in the following description, the reference numerals attached to FIGS. 4 to 7 are also cited. First, regarding the guard panel 4, the concave portions 31 are formed on the inner surfaces of the third surface portions 8 and 9 at both ends thereof, instead of the conventional convex portions. The recess 31 extends over a wide range excluding only 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 movable die 22, which is the second die member forming the inner surface of the guard panel 4, has the guard formed on the surface forming the third surface portions 8 and 9. A trapezoidal convex portion 32 that forms the concave portion 31 of the panel 4 is formed. The lower surface of the convex portion 32 is located closer to the fixed die 21 which is the first die member than the cavity, and has an undercut shape in the die opening direction of the movable die 22. In addition, the peripheral side surfaces including the lower surface of the convex portion 32 are inclined so as to allow mold release.

Next, a molding method using this mold will be described. At the time of molding, as shown by the solid line in FIG. 1, the resin filled in the cavity formed between the fixed mold 21 and the movable mold 22 with the mold closed is sufficiently cooled and solidified, and then shown by the chain line in FIG. In this way, the fixed mold 21 and the movable mold 22 are opened. At this time, the molded guard panel 4 first stops on the movable die 22 side and separates from the fixed die 21. In particular, the outer surface of the first surface portion 6 has a resistance against the mold release from the fixed mold 21, but the mold release caused by the ridge 12 of the first surface portion 6 and the concave portion 31 of the third surface portions 8 and 9 The guard panel 4 stops on the movable die 22 side due to the resistance. Then, after the fixed die 21 is sufficiently separated from the guard panel 4, the ejection pins 25 start to rise with respect to the movable die 22 and are ejected by these ejection pins 25, and the guard panel 4 is separated from the movable die 22. At this time, the lower portion of the concave portion 31 of the third surface portions 8 and 9 of the guard panel 4 has the convex portion 32 of the movable die 22 forming the concave portion 31 due to the elastic deformation of the third surface portions 8 and 9 outward. get over. That is, the recess 31 of the guard panel 4 is forcibly removed.

As described above, due to the undercut shape of the convex strip 12 and the concave portion 31, the guard panel 4 is stopped on the movable die 22 at the start of mold opening. In particular, the concave portion 31 of the third surface portion 8, 9 is used. Can increase the amount of undercut, that is, the depth, as compared to the conventional convex portion, and since it covers a wide range of the third surface portions 8 and 9, it has a large release resistance to the movable die 22. The guard panel 4 can be reliably prevented from following the fixed mold 21 at the start of mold opening. This also prevents the outer surface of the guard panel 4 from being scratched.

Further, the third surface portions 8 and 9 of the guard panel 4 can be thinned by the amount of the recess 31. Nevertheless, since a thick portion remains in the peripheral portion of the inner surfaces of the third surface portions 8 and 9, it is possible to secure the thickness required for the incorporation into the cassette 2 in this portion. That is, when the guard panel 4 is incorporated in the cassette 2, there is no large gap between the side surface of the cassette 2 and the third surface portions 8 and 9. This also prevents rattling of the guard panel 4 with respect to the cassette 2. Further, in addition to the first surface portion 6 and the second surface portion 7, the third surface portions 8 and 9 are thinned to the same extent by the recess 31, so that the third surface portions 8 and 9 fall down due to the shrinkage of the resin during molding. Can be prevented. Thus, it is possible to save the material and provide the guard panel 4 which is excellent in accuracy and formability.

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 in the above embodiment, and for example, a plurality of small concave portions may be formed on the inner surface of each third surface portion. Good.

[0019]

[Effect of device]

 According to the invention of claim 1, in the VTR cassette tape guard panel, the inner surface of the third surface portion at both ends in the longitudinal direction is formed with the recesses located apart from the end edges thereof, so that at least the third surface portion is formed. Prevents the guard panel from rattling against the cassette due to the gap between the side surface of the cassette and the third surface when assembled to the cassette due to the thick part on the periphery. However, the third surface can be thinned by the amount of the recess. As a result, in addition to the other first surface portion and the second surface portion of the guard panel, the third surface portion can be thinned to the same degree. Therefore, when the guard panel is molded, the third surface portion collapses due to the shrinkage of the resin. Can be prevented. In this way, it is possible to save material and provide a guard panel with excellent precision and moldability.

Further, according to the invention of claim 2, it is provided with a first mold member forming an outer surface of the guard panel and a second mold member forming an inner surface of the guard panel, and both molds are provided. In the molding die in which the opening / closing direction of the member is substantially parallel to the third surface portion of the guard panel, the recess of the guard panel is formed on the surface of the second die member on which the third surface portion is formed. Since the convex portions are formed, these concave portions and convex portions have an undercut shape with respect to the mold opening direction of the second mold member. However, as compared with the case where the relationship of concave and convex is opposite between the guard panel side and the mold side. Even if the mold release resistance of the first mold member is large at the start of mold opening, the molded guard panel should first stop on the second mold member even if the undercut amount is large. About the mold parts of It can be surely prevented. This also prevents the outer surface of the guard panel from being scratched.

[Brief description of drawings]

FIG. 1 shows an embodiment of a guard panel molding die of the present invention, and is a vertical cross-sectional view of the die 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 molded 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. 6 above.

FIG. 8 is a vertical cross-sectional view of the same mold closed state.

FIG. 9 is a vertical cross-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]

 4 Guard panel 6 1st surface part 7 2nd surface part 8 3rd surface part 9 3rd surface part 21 Fixed mold (1st mold member) 22 Movable mold (2nd mold member) 25 Extrusion pin (Extrusion member) 31 Recessed part 32 convex

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area // B29L 31:34 4F

Claims (2)

[Scope of utility model registration request] 1. An elongated first surface portion and a second surface portion which are connected at one end edge along the longitudinal direction and are substantially orthogonal to each other, and a first shape bent from both end edges of the first surface portion and the second surface portion along the lateral direction. In a guard panel for a VTR cassette tape, which has a surface portion and a pair of third surface portions substantially orthogonal to the second surface portion, and which is integrally molded with resin, a recessed portion located on the inner surface of the third surface portion and apart from the end edge thereof. A guard panel for a VTR cassette tape, which is characterized in that 2. A VTR cassette tape guard panel according to claim 1, wherein the VTR cassette tape guard panel is molded, and a first mold member forming an outer surface of the guard panel and an opening / closing mechanism for 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 molded guard panel from the second mold member side, In a molding die in which the opening and closing directions of both the die members are substantially parallel to the third surface portion, the guard panel is formed on the surface of the second die member that forms the third surface portion. A mold for molding a VTR cassette tape guard panel, characterized in that a convex portion that forms a concave portion is formed.