JPH0737056B2 - Mold for two-color molding of upper cassette half of digital voice recording tape - Google Patents

Description

TECHNICAL FIELD The present invention relates to a two-color molding die for manufacturing an upper cassette half of a digital audio recording tape.

"Prior Art" FIG. 5 shows an example of an upper cassette half of a digital voice recording tape.

This cassette half 1 comprises a window portion 2 and prism portions 3 and 3 integrally formed of transparent resin, and a frame portion 4 made of colored resin. The prism portion 3 and 3 are shown in FIG. Thus, the incident light L from the recorder is reflected and used for detecting the magnetic surface of the tape T.

Conventionally, when this kind of cassette half 1 is manufactured by a two-color molding method, a mold reversing device is used to rotate the core mold in a plane orthogonal to the mold release direction of the molded product, and the primary side mold mold Also, a so-called rotational molding method is adopted in which two stages of molding are sequentially performed by alternately facing the secondary mold and the secondary mold.

[Problems to be Solved by the Invention] However, in the above-described conventional rotational molding method, two types of molds, a primary side and a secondary side, are required, which is costly, and after the molding on the primary side is completed. Since the mold is once opened and the primary side molded article is rotatably transferred to the secondary side, the molding cycle is long and the productivity is low. further,
There is also a problem that the interface between the primary and secondary moldings tends to peel off after molding since the primary molded product comes into contact with the outside air when the mold is opened after primary molding.

"Means for Solving Problems" The present invention has been made to solve the above problems, and a cavity having a shape corresponding to the entire upper cassette half is defined between the fixed mold plate and the movable mold plate which face each other. As well as
Primary injection path that opens into the window / prism molding space of the cavity that integrally molds the prism half and window of the cassette half, and secondary injection that opens into the frame molding space of the cavity that molds the frame of the cassette half Forming a road,
A movable mold body capable of closing the frame molding space is provided in the fixed mold plate, and a split mold mechanism for molding the prism portion is provided in the movable mold plate.

"Operation" In this mold, the molding space of the frame of the cavity is closed by the movable mold, and the transparent resin is injected into the cavity from the primary injection path to primary mold the window and prism parts. The upper cassette half is efficiently two-color molded by injecting the colored resin from the secondary injection path after releasing the blockage by the body to secure a space for molding the frame portion.

[Examples] Examples of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 4 show an embodiment of a two-color molding die for the upper cassette half 1.

In the figure, reference numeral 10 is a fixed mold plate, and this fixed mold plate 10 is attached to a fixed mounting plate 14 via first, second, and third fixed receiving plates 11, 12, and 13. Further, a movable mold plate 15 is provided so as to face the fixed mold plate 10, and the movable mold plate 15 is a movable receiving plate 16
And a movable mounting plate (not shown) via a spacer block (not shown). A cavity 17 having a shape corresponding to the entire upper cassette half 1 is defined between the mold plates 10 and 15 so that the fixed mold plate 10 side is the upper surface of the cassette half.

In the fixed mold plate 10, a movable mold body 18 having a flat surface facing the cavity 17 is housed so as to project into the cavity 17. When this is projected, the frame molding space 17 of the cavity 17 is housed.
B is closed as shown in FIG. In this state, a space for molding the side plate portion of the frame portion 4 is open, but communication with the window / prism portion molding space 17A is cut off by the movable mold body 18. Further, as shown in FIG. 3, a part of the movable mold body 18 includes a fixed mold plate 10 and first and second fixed receiving plates 1.
It penetrates through 1, 12 and is connected to a receiving body 19 housed in a third fixed receiving plate 13 so as to be movable in the mold opening / closing direction.
Further, 19 is connected to a piston rod 20A of a hydraulic cylinder 20 formed in the third fixed receiving plate 13. As a result, when the piston rod 20A is moved forward, the movable mold body 18
Are projected into the cavity 17.

Further, the hot runner manifold block 21 is attached to the fixed mounting plate 14 as shown in FIG. 1, and the window portion of the cavity 17 is passed through the manifold block 21 and the first and second fixed receiving plates 11 and 12. A primary injection path 22 opening to the prism part molding space 17A and a secondary injection path 23 opening to the frame part molding space 17B are formed. Note that 2
4 and 25 are heaters.

On the other hand, inside the movable mold plate 15, a split mold mechanism 26 for molding the prism portion is housed, as shown in FIG. This split mold mechanism 26 constitutes a side wall of the prism portion molding space and is biased in a direction away from the space, and the split mold 27.
Movable template 15 having taper surface 28A that contacts taper surface 27A of 27
It comprises a taper member 28 which is movable in the mold opening / closing direction inside, and when the taper member 28 is moved in the mold opening direction, the prism portion 3 is released from the mold as shown by the chain double-dashed line in the figure. ing.

Next, a procedure for molding the cassette half 1 using the two-color molding die having the above configuration will be described.

First, simultaneously with the start of mold clamping, the piston rod 20A of the hydraulic cylinder 20 is advanced to project the movable mold body 18 into the cavity 17 and close the frame part molding space 17B. Then, the transparent resin is injected into the cavity 17 through the primary injection path 22,
The window portion 2 and the prism portions 3, 3 of the cassette half 1 are primarily molded.

Next, the piston rod 20A is retracted to move the movable mold body 18
Is drawn into the fixed mold plate 10 to release the frame part molding space 17B, and then the colored resin is injected into this space 17B through the secondary injection path 23 to secondary mold the frame part 4.

After solidification, the mold opening is started, the taper member 28 is moved in the mold opening direction, the split mold 27 is separated from the prism portion 3, and the cassette half 1 is separated.

As described above, according to the two-color molding die, since the primary molding and the secondary molding can be continuously performed in one die, the die cost can be reduced as compared with the conventional rotational molding method. At the same time, it is possible to shorten the molding cycle and improve the productivity.

Further, since it is not necessary to open the mold after the primary molding, the primary molded article does not come into contact with the outside air, and there is an advantage that the weldability at the interface between the primary and secondary molding is enhanced and peeling can be prevented.

[Effects of the Invention] As described above, according to the two-color molding die of the upper cassette half of the digital audio recording tape of the present invention, the molding space of the cavity is closed by the movable mold body and the primary injection is performed. The transparent resin is injected into the cavity from the channel to primary-mold the window and prism parts, then the blockage by the movable mold is released to secure a space for molding the frame, and then the colored resin is injected from the secondary injection channel. By injecting, it is possible to continuously perform primary molding and secondary molding in one mold, so that it is possible to reduce the mold cost, shorten the molding cycle, and improve the productivity. it can. Also,
Since the mold does not have to be opened after the primary molding, the primary molded product does not come into contact with the outside air, and the weldability at the interface between the primary and secondary moldings can be improved.

[Brief description of drawings]

1 to 4 show a two-color molding die of the present invention. FIG. 1 is a sectional view in a state where secondary molding is carried out, and FIG. 2 is a sectional view in a state where primary molding is carried out. Figure 3 is in Figure 1
FIG. 4 is a sectional view taken along line III-III and FIG. 4 is a sectional view showing a split mold mechanism for molding a prism portion. 5 is a plan view of the upper cassette half of the digital audio recording tape, and FIG. 6 is a sectional view taken along the line VI-VI in FIG. 1 ... Upper cassette half, 2 ... Window part, 3 ... Prism part,
4 ... Frame part, 10 ... Fixed mold plate, 14 ... Fixed mounting plate, 15 ... Movable mold plate, 16 ... Movable receiving plate, 17 ... Cavity, 17A ... Window / prism part molding space, 17B ... Frame part molding space, 18 ... Movable body, 1
9 ... Receptor, 20 ... Hydraulic cylinder, 22 ... Primary injection path, 23 ... Secondary injection path, 26 ... Split mold mechanism, 27 ... Split mold, 28 ... Tapered member.

Claims (1)

[Claims] 1. A cavity having a shape corresponding to the entire upper cassette half of a digital voice recording tape is defined between a fixed mold plate and a movable mold plate facing each other, and a window portion and a prism portion of the cassette half are integrally molded. Forming a primary injection path that opens into the window / prism part molding space of the cavity and a secondary injection path that opens into the frame part molding space of the cavity that molds the frame part of the cassette half; A movable mold body capable of closing the above is provided in a fixed mold plate, and a split mold mechanism for molding the prism portion is further provided in the movable mold plate. Two-color molding die.