JPS6337220Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hub for a tape cartridge.

A pair of hubs are rotatably disposed within the case of the magnetic tape cartridge, and the magnetic tape is wound around the outer circumferential surface of the hub. Since the hub is molded from a synthetic resin, if it is relatively thick and solid, so-called sink marks occur during molding, and as a result, there is a problem in that the roundness and perpendicularity of the outer circumferential surface of the hub cannot be ensured.

Therefore, in order to solve this problem, as shown in FIGS. 1 and 2, the outer ring portion 2 and the other portions 3
A hub 1 is provided which is molded separately and integrally joins them together. This type of hub 1 does not cause sink marks on the outer circumferential surface because the outer ring part 2 can be made thin, and by making the outer ring part 2 and the other part 3 different colors, it can be used as a hub of a single color. In comparison, it has the advantage of making the wearer more attentive and convenient for checking the rotational state and direction of the hub. However, the outer ring portions 2, which have different colors, must be seen through a see-through window in the case, which causes the color clarity to fade, and in cases with small see-through windows, it is very difficult to see. Since the width of the color cannot be made very wide, it has the disadvantage that it is difficult to emphasize the contrast between different colors.

An object of the present invention is to provide a hub that eliminates the above-mentioned drawbacks, allows easy observation of the rotational state of the hub, and prevents sink marks on the outer circumferential surface. In order to achieve this object, the present invention includes a plurality of locking claws protruding from an inner circumferential surface, an outer ring portion around which the tape is wound, and a connecting portion connecting the outer ring portion and the locking claws. a first molded body made of synthetic resin, each having a first molded body, and a second molded body made of a synthetic resin of a different color from the first molded body, and filled so as to wrap around the connecting portion.
A molded body is provided, and the first molded body and the second molded body are integrally connected.

Hereinafter, embodiments of the present invention will be explained based on FIGS. 3 to 8.

The hub 1 is composed of a first molded body 4 and a second molded body 5, and both molded bodies 4 and 5 are integrally joined. A recess 6 is formed in a part of the outer periphery of the hub 1, and a clamp 7 is firmly fitted into the recess 6 through the end of a tape (not shown) such as a leader tape or magnetic tape, thereby causing the above-mentioned A tape is attached to the outer circumference of the hub 1. The first molded body 4 and the second molded body 5 are obtained by injection molding in two stages using synthetic resins of different colors, such as polyacetal resin, ABS resin, and polyamide resin.

First, the structure of the first molded body 4 will be explained using FIG. 3 and FIG. It is mainly composed of an outer ring portion 9 and a connecting portion 10 that connects the locking pawls 8 and the outer ring portion 9 at approximately the center in the axial direction. In particular, in order to suppress sink marks appearing on the outer circumferential surface of the outer ring part 9 as much as possible, the outer ring part 9 and the connecting part 10 are designed to have substantially the same thickness and to be thin, as shown in FIG. A plurality of through holes 11 are provided in the connecting portion 10 at approximately equal intervals along the circumferential direction, and the upper surface and the lower surface of the connecting portion 10 are communicated through these through holes 11 .

As shown in FIGS. 5 and 6, the second molded body 5 is provided inside the outer ring portion 9 so as to wrap around both upper and lower surfaces of the connecting portion 10 of the first molded body 4. In other words, the first molded body 4 is obtained in the primary molding, and the second molded body 5 is formed in the next secondary molding.
Since the synthetic resin used for the molded body 4 and the synthetic resin used for the second molded body 5 are different colors,
The color of the outer ring portion 9 and the locking claw 8, and the color of the outer ring portion 9
and the second molded body 5 located between the locking claw 8 and the second molded body 5 have a different color. Furthermore, as shown in FIG. 6, since the second molded bodies 5 on the upper and lower sides of the connecting portion 10 are integrated through the through hole 11, even if an impact force is applied to the hub 1 after molding, both the molded bodies 4 and 5 will remain intact. It doesn't shift or separate.

FIG. 7 and FIG. 8 are diagrams for explaining the manufacturing process of the hub 1, and FIG. 5 shows the process during mold closing,
FIG. 6 shows the molds when they are opened.

In the primary molding, as shown in FIG. 7, first the fixed mold 12 for primary molding and the movable mold 13 are combined, and a red molten synthetic resin, for example, is injected into the space between them to mold the first molded body 4. . Next, in FIG. 8, after the first molded body 4 is cooled and solidified, both molds 12, 1
3, the first molded body 4 and the movable mold 13 are separated from the fixed mold 12 due to the mold release resistance.
After only the sprue runner of the first molded body 4 is protruded and discharged, the movable mold 13 with the first molded body 4 attached thereto is pivoted to a position just below the fixed mold 14 for secondary molding.

In the secondary molding, returning to FIG. 7 again, after the inserts 15 and 16 of the rotated movable mold 13 have each moved downward by a predetermined amount, the movable mold 13 and the fixed mold 14 for secondary molding are combined. . And both molds 13, 14
A molten synthetic resin colored in a color different from that of the first molded body 4, for example, white, is injected into the first molded body 4.
The second molded body 5 is molded using this as a core. Then the 8th
In the figure, the second molded body 5 is inside both molds 13 and 14.
After cooling and solidifying, when both molds 13 and 14 are opened again,
At this time as well, the hub 1 composed of the first molded body 4 and the second molded body 5 is separated from the movable mold 13 and the fixed mold 14 for secondary molding due to the mold release resistance. Then, as shown in the figure, the hub 1 is taken out from the movable mold 13 by the protruding pin 17, the movable mold 13 is pivoted again to just below the primary molding mold 12, and this series of operations is repeated thereafter. The hub 1 is continuously molded by the following steps.

As detailed above, according to the present invention, in addition to the outer ring part of the hub, the locking claws on the inner peripheral surface can also be made in a different color from other parts, making it easy to check the rotational state of the hub. becomes easier. Moreover, since the first molded body is reinforced by the second molded body, the outer ring portion of the first molded body can be designed to be relatively thin, and sink marks can be prevented from occurring on the outer peripheral surface of the hub.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional hub, FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1, FIGS. 3 to 8 show embodiments of the present invention, and FIG. plan view of
Figure 4 is a sectional view taken along the line B-B in Figure 3, Figure 5 is a plan view of the completed hub, Figure 6 is a sectional view taken along the line C-C in Figure 5, and Figures 7 and 8 are the hub. It is an explanatory diagram showing a manufacturing process of. DESCRIPTION OF SYMBOLS 1... Hub, 4... First molded body, 5... Second molded body, 8... Locking claw, 9... Outer ring part, 10... Connection part.

Claims (1)

[Scope of utility model registration request] A first molded body made of synthetic resin, each having a plurality of locking claws protruding from an inner peripheral surface, an outer ring portion around which a tape is wound, and a connecting portion connecting the outer ring portion and the locking claws; , a second molded body made of a synthetic resin of a different color from the first molded body and filled so as to wrap around the connecting portion, and the first molded body and the second molded body are integrally connected. A hub for tape cartridges characterized by: