JPH0512830A - Metallic mold structure for molding tape guide block - Google Patents

Abstract

(57) [Abstract] [Purpose] The realization of a die structure for providing a guide block in which the back tension of the tape can be an appropriate value regardless of the type of the tape cassette. [Structure] In one mold body 30, a plurality of space for forming both side guide parts set at various mounting angles with respect to the guide block body is provided in a portion corresponding to both side guide parts in the space for forming the guide block. The rotator 40 is rotatably loaded in the substantially cylindrical rotator 40 in which
Is rotated so that the guide block molding operation can be performed in a state where the desired space for molding both side guide portions is continuous with the molding space of the guide block main body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold structure suitable for molding a tape guide block mounted inside a housing of a tape cassette.

[0002]

2. Description of the Related Art Conventionally, in a tape cassette, a tape path system around a front opening into which a magnetic head or the like is inserted is formed of a material different from that of the cassette half, thereby reducing friction, vibration, and running. There is a device which improves the accuracy of the path and thereby reduces the modulation noise.

First, the structure of this type of tape cassette will be described with reference to FIGS. 1 in these figures
Is an upper half, 2 is a lower half, and the upper half 1 and the lower half 2 are combined and fixed with screws B at several places to form a cassette housing.

A pair of reel hubs 4 around which the magnetic tape T is wound are rotatably housed in the cassette housing, and the magnetic tape T wound around the reel hub 4 is provided on the left and right sides of the lower half 2. The guide pin 5 and the guide roller 6 which is rotatably supported are guided to the front opening 7. The reel hub 4 and the upper and lower halves 1,
The slippery sheets 3a and 3b are interposed between the two.

From the front opening 7, the magnetic head 20 and the pinch roller 2 from the side of the recording / reproducing apparatus at the time of tape recording / reproducing.
1 is inserted into the magnetic tape T to perform a recording / reproducing operation. Inside the front opening 7, a guide block 8 having a function such as a guide for running the magnetic tape T is provided.
Are arranged and fixed so as to be sandwiched between the upper and lower halves 1, 2.

The guide block 8 is formed separately from the upper and lower halves 1 and 2 by a material having low friction and excellent vibration absorption, and a partition wall portion 9 for partitioning the front opening 7 and the tape storage portion.
And a plurality of guide projections 10a to 10f that project from the partition wall 9 toward the front opening 7 side, and the front opening 7 is provided at the tip of the guide projections 10a to 10f. A stable tape running path is formed by slidingly guiding the base surface side of the passing magnetic tape T. Further, a shield plate 11 is fitted between the guide protrusions 10c and 10d at the center of the guide block 8, and the head pressure bonding pad 12 is placed in front of the shield plate 11 and is supported by a leaf spring 13 so as to extend therethrough. ing.

[0007]

In the tape cassette constructed as described above, sufficient running accuracy of the magnetic tape T is obtained in the portion guided by the guide block 8, but other tape guide portions, that is, guides. The tape running accuracy of the pin 5 and the guide roller 6 is not so high, and therefore there is a limit in ensuring stable running accuracy in the entire tape running path. Therefore shifted in the tape running path tends to occur anyway, resulting tape recording / level difference of the phase difference and the left and right channels at the time of reproduction, there is a disadvantage that irregular winding such occurs.

Further, the guide pin 5 in such a tape cassette also has a function of applying a required back tension to the magnetic tape T when the magnetic tape T is running so that the magnetic tape T can be stably run. is doing. The back tension applied to the magnetic tape T depends on two factors: the wrap angle of the magnetic tape T with respect to the guide pin 5, and the coefficient of friction between the guide pin 5 and the base surface of the magnetic tape T. Is.

In the above-described conventional tape cassette, the guide pin 5 is integrally provided on the lower half 2 to project.
That is, since it is fixed to the cassette housing, the above 2
Of the two back tension factors, the back tension due to the winding angle of the magnetic tape T with respect to the guide pin 5 is constant regardless of the type of the magnetic tape T.

On the other hand, there are various types of magnetic tapes built in the cassette housing, and the friction coefficient with respect to the guide pin 5 depends on the difference in the material of the base film of the magnetic tape and the presence or absence of coating (back coating) on the base surface side. It will be very different. Therefore, the back tension during running changes depending on the type of magnetic tape built into the cassette housing.

This fluctuation in back tension has a great influence on the running state of the magnetic tape. That is, if the back tension is larger than the proper value, the magnetic tape is apt to cause a stick slip between the pinch roller and the capstan, which causes the wow and flutter to worsen. Since the degree of close contact with the magnetic surface of the magnetic tape is small, spacing loss is large and the output level may be low or track deviation may occur.

[0012]

SUMMARY OF THE INVENTION The present invention proposes a mold structure suitable for forming a guide block when providing a tape cassette equipped with a guide block capable of solving such a problem. To do. That is, as a tape guide system inside the tape cassette, a guide block having a guide block main body part for guiding the tape passing through the front opening of the cassette housing and both side guide parts for applying back tension to the tape is provided. An object of the present invention is to provide a mold structure for molding, and in particular, a mold structure capable of molding a guide block in which back tension values obtained by the guide portions on both sides of the guide block are variously set. To do.

Therefore, in one of the mold bodies provided with the guide block molding space, various mounting angles are set with respect to the guide block body space at portions corresponding to both side guide portions in the guide block molding space. A substantially cylindrical rotating body having a plurality of space for forming both side guide portions formed therein is loaded, and the rotating body is rotated,
By performing the guide block forming operation with the desired space for forming both sides of the guide block continuous with the forming space of the guide block main body, the both side guides are formed at various desired forming angles with respect to the guide block main body. The guide block is configured so that it can be molded.

[0014]

With the above die structure, it is possible to obtain a guide block in which the winding angle of the tape around the guide parts on both sides is set according to the friction coefficient between the tape and the guide parts on both sides. It is possible to mold various guide blocks that are always provided with an appropriate back tension according to the type of tape to be formed, using only the mold having this configuration.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a tape cassette having a guide block molded by a tape guide block molding die structure of the present invention will be described with reference to FIGS. 5 is an exploded perspective view of the tape cassette, FIG. 6 is a plan view of the tape cassette, FIG. 7 is a plan view of a guide block, FIG. 8 is a perspective view of both guide portions of the guide block, and FIG. 9 is a guide block fixing method. FIG. In addition, in FIG.
The parts corresponding to those of the conventional example of FIG. 11 are designated by the same reference numerals, and the description thereof will be omitted.

This tape cassette has a structure in which the guide block 8 arranged in the front opening 7 is integrated with the guide pin 5 and the guide roller 6 in the conventional tape cassette shown in FIGS. ing. That is, as is clear from FIGS. 5 to 8, in the guide block 8, the partition wall portion 9 and the guide protrusion portions 10a to 10f.
The guide block main body portion in which the ridges are formed is continuously connected to the left and right ends of the guide block body portion and the arc-shaped guide portion 14 and the pin-shaped guide portion 1.
5 is integrally formed, that is, the arc-shaped guide portion 14 and the pin-shaped guide portion 15 correspond to the guide pin 5 and the guide roller 6 in the conventional tape cassette.

Therefore, the magnetic tape T wound around the reel hub 4 is guided to the front opening 7 by guiding the base surface of the magnetic tape T in sliding contact with the arc-shaped guide portion 14 and the pin-shaped guide portion 15. It is done like this.

The guide block 8 is fixed to the cassette housing by the left and right circular arc-shaped guide portions 14 and the center screw hole 8a formed in the central portion.
In other words, the annular boss portion 16 projects on the inner surface side of each of the upper and lower halves 1 and 2 at the position corresponding to the arc-shaped guide portion 14 (that is, the position where the guide roller 6 is arranged in the conventional tape cassette). As shown in FIG. 9, the boss portion 16 is attached to the arc-shaped guide portion 14 at the time of assembly.
The left and right ends of the guide block 8 are fixed by fitting the inner peripheral surfaces 14a of
A screw B for fixing the central portion of the cassette is inserted into the center screw hole 8a when fixing the screw, and the central portion of the guide block 8 is fixed.

As a molding material for the guide block 8, a material having a high slidability for reducing friction with respect to the magnetic tape T, a material which does not resonate even with a thin structure, and which has a not so high rigidity for absorbing vibration, Those with high molding precision,
Need to choose. To meet these conditions,
For example, high-rigidity type HDPE, POM, PA and ABS resins are suitable.

By using such a material, the guide block 8 has a low friction on the sliding surface with respect to the base surface of the magnetic tape T, so that the vibration due to the tape sliding hardly occurs, and the vibration from the outside is absorbed. By doing so, the magnetic head is not affected by the vibration, and therefore the tape modulation noise is suppressed to a small level. Further, since the above materials are relatively inexpensive, they are suitable for cost reduction.

The guide block 8 is integrally formed with the arc-shaped guide portion 14 and the pin-shaped guide portion 15 corresponding to the guide roller and the guide pin of the conventional tape cassette, and the base surface of the magnetic tape T is slidably contacted. By using a structure in which all the guide parts are integrated, the positional relationship between the guide parts can be made constant, which improves the running accuracy of the magnetic tape T, and as a result, the position during tape recording / reproduction can be improved. The phase difference and the level difference between the left and right channels are improved, and winding disorder can be reduced. Of course, since the guide roller and the guide pin are unnecessary, there is an advantage that the number of parts and the number of assembling steps can be reduced.

By the way, in such a guide block 8, the pin-shaped guide portion 15 corresponding to the guide pin of the conventional tape cassette has a function of applying back tension to the magnetic tape T. That is,
A predetermined level of back tension is given by the coefficient of friction between the pin-shaped guide portion 15 and the base surface of the magnetic tape T and the winding angle of the magnetic tape T with respect to the pin-shaped guide portion 15. As described above, the friction coefficient between the pin-shaped guide portion 15 and the base surface of the magnetic tape T changes depending on the type of the magnetic tape T loaded in the tape cassette.

Therefore, in order to maintain the back tension at an almost proper value in various tape cassettes, the winding angle of the magnetic tape T with respect to the pin-shaped guide portion 15 is set in various tape cassettes (the tape cassette is loaded in the tape cassette). It has to be changed according to the magnetic tape T).

In the guide block 8 of this example, the pin-shaped guide portion 15 is changed by variously changing the forming angle of the pin-shaped guide portion 15 with respect to the guide block main body portion.
The wrapping angle of the magnetic tape T with respect to can be changed.

Now, for example, as shown in FIGS. 4A to 4G, + 15 ° to −15 ° with reference to FIG. 4D.
In this range, seven types of guide blocks 8 having different molding angles of the pin-shaped guide portion 15 with respect to the guide block body portion are prepared. Then, it is possible to deal with seven types of magnetic tapes T having different friction coefficients when sliding with the pin-shaped guide portion 15.

That is, in the guide block 8 of FIGS. 4C, 4B, and 4A, the back tension obtained depending on the winding angle of the magnetic tape T becomes smaller than that of the guide block 8 of FIG. 4D. On the other hand, as compared with the guide block 8 of FIG. 4D, the back tension obtained by the winding angle of the magnetic tape T in the guide blocks 8 of FIGS.

Therefore, depending on the type of magnetic tape used, the back tension can be maintained at a substantially proper value by using the guide block 8 in which the pin-shaped guide portion 15 has a forming angle.

The results of actually measuring the back tension of three types of magnetic tapes [A], [B] and [C] having different friction coefficients are shown below. The back tension is 8.0g
The front and back are proper values. Further, in these magnetic tapes [A], [B], and [C], when the guide block 8 of FIG. 4 (d) in which the molding angle of the pin-shaped guide portion 15 is the standard angle is used, the back tension does not have an appropriate value. The one that disappears is adopted.

Magnetic tape [A] When using a standard guide block (Fig. 4 (d)) ... 8.5 g -5 ° adjustment guide block (Fig. 4 (c)) When using ・ ・ ・ ・ ・ ・ 8.0 g ・ With magnetic tape [B] standard guide block (Fig. 4 (d)) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 7.2 g + 15 ° When using the adjustment guide block (Fig. 4 (g)) ・ ・ ・ ・ 7.9 g ・ When using the magnetic tape [C] standard guide block (Fig. 4 (d)) ・ ・ ・ ・・ ・ ・ ・ ・ ・ When 9.7 g −10 ° adjustment guide block (Fig. 4 (b)) is used ・ ・ ・ ・ 7.8 g

That is, as the guide block 8, a pin-shaped guide portion 15 having a standard forming angle (FIG. 4 (d)) is not used, but according to the magnetic tape T loaded in the tape cassette. Pin-shaped guide part 15
It is understood that the back tension can be maintained at an appropriate value of around 8.0 g in any tape cassette by using the guide block 8 whose molding angle is adjusted.

The tape guide block molding die structure of the present invention is capable of molding various guide blocks 8 as shown in FIGS. 4 (a) to 4 (f). One embodiment will be described with reference to FIGS.

FIG. 1 is a plan view of one mold body (core) 30, in which the guide block 8 is provided.
Body part (partition wall portion 9, guide protrusion portions 10a to 10f,
And a resin injection space 31 for molding a portion corresponding to the arc-shaped guide portion 14) is formed, and both end portions of the resin injection space 31 have a cylindrical shape as shown in the partial perspective views of FIGS. 1 and 2. A hollow portion 32 is formed, and the hollow portion 32 is loaded with a substantially cylindrical rotating body 40. The rotating body 40 is fitted in the inner wall of the hollow portion 32 with its peripheral surface in a close contact state, and is rotatable by, for example, a rotating mechanism (not shown) attached to the bottom surface side of the core 30.

The guide block 8 is attached to the rotating body 40.
7, for example, seven resin injection spaces 41a to 41g corresponding to the pin-shaped guide portion 15 are provided, and any one of the resin injection spaces 41a to 41g is selectively rotated by rotating the rotating body 40 as shown in FIG. Further, the space is continuous with the resin injection space 31 of the core 30.

Then, the resin injection spaces 41a to 41g
Either one of them is the resin injection space 3 of the core 30.
As shown in the sectional view of FIG. 3, the other planar mold body (cavity) 50 is pressure-welded in a state where the resin injection space 31 and the resin injection space 31 are continuous with each other. Resin injection space 41 (41a-
The guide block 8 is molded by injecting resin into any of 41 g.

Here, the resin injection spaces 41a to 41g
The pin-shaped guide portions 15 that are respectively molded are shown in FIG.
It corresponds to (a) to (g). That is, the pin-shaped guide portion 15 is guided by the resin injection space 41d at a standard molding angle (see FIG. 4).
When (d) is assumed to be molded, the resin injection spaces 41a to 41c and 41e to 41g allow the molding angle with respect to the guide block main body portion from + 15 ° to −−.
Each resin injection space 41a is formed so that six types of angle-adjusted pin-shaped guide portions 15 up to 15 ° are formed.
The formed angle of about 41 g is set.

Therefore, in the mold structure of this embodiment, when the rotating body 40 is rotated to make the resin injection space 41a continuous with the resin injection space 31 of the core 30, the structure shown in FIG.
The guide block 8 of (a) can be molded, and similarly, when the resin injection space 41b is continuous with the resin injection space 31, the resin injection space 41c shown in FIG. 4 (b).
4 when the resin injection space 31 is connected to the resin injection space 31.
(C) ... The seven types of guide blocks shown in FIG. 4 can be molded. That is, the mold structure of this embodiment can provide a guide block that realizes proper back tension for a tape cassette that employs various magnetic tapes.

In the mold structure of the above-described embodiment, the rotary body 40 can be formed with the pin-shaped guide portions 15 of seven kinds of angles, but the number of kinds is not limited to seven, and the guide block to be manufactured is not limited to seven kinds. It may be set according to the type of. Any rotating mechanism may be used for the rotating body. However, the rotating mechanism should be provided with a click mechanism so that each of the resin injection spaces 41a to 41g corresponds to a position continuous with the resin injection space 31 with a click feeling during rotation. Is desirable.

Furthermore, without particularly providing a mechanism for rotating operation,
Even if the rotator 40 cannot rotate (difficult) when it remains fitted in the recess 32, the rotator 40 can be easily inserted into and removed from the recess 32. That is, when changing the angle of the pin-shaped guide portion 15, the rotating body 40 is once taken out from the recess 32, and the desired resin injection space (41
a to 41 g) may be adjusted to a position continuous with the resin injection space 31 and the molding angle of the pin-shaped guide portion 15 of the guide block 8 that is molded by being fitted again may be adjusted.

[0039]

As described above, in the tape guide block molding die structure of the present invention, it is possible to mold the guide block in which the tape winding angle on the both side guide portions is adjusted according to the friction coefficient. That is, there is an effect that various guide blocks capable of giving an appropriate back tension according to the type of tape contained in the tape cassette can be molded only by the mold according to the present invention. Therefore, it is possible to easily provide a tape cassette in which the back tension of the magnetic tape has an appropriate value regardless of the type of the tape cassette.

[Brief description of drawings]

FIG. 1 is a plan view of a core in one embodiment of a tape guide block molding die structure of the present invention.

FIG. 2 is a partial perspective view of a core of this embodiment.

FIG. 3 is a sectional view taken along the line AA of this embodiment.

FIG. 4 is an explanatory view of various forming angles of the pin-shaped guide portion of the guide block according to the present embodiment.

FIG. 5 is an exploded perspective view of a tape cassette in which a guide block is formed according to this embodiment.

FIG. 6 is a plan view of a tape cassette having a guide block formed according to the present embodiment.

FIG. 7 is a plan view of a guide block molded according to this embodiment.

FIG. 8 is a partial perspective view of a guide block molded according to this embodiment.

FIG. 9 is an explanatory diagram of a fixing method of a guide block molded according to this embodiment.

FIG. 10 is an exploded perspective view of a conventional tape cassette.

FIG. 11 is a plan view of a conventional tape cassette.

[Explanation of symbols]

 30 core 31 resin injection space 32 hollow portion 40 rotating body 41a to 41g resin injection space 50 cavity

Claims (1)

Claim: What is claimed is: 1. A guide block main body which is mounted in a cassette housing constituted by upper and lower halves and which guides a tape passing through a front opening of the cassette housing, and a back tension applied to the tape. A guide block molding space is provided as a mold structure for molding a guide block configured to have both side guide portions that correspond to the both side guide portions in the guide block molding space. In the portion to be filled, a substantially cylindrical rotating body having a plurality of space for forming both side guide portions set at various mounting angles with respect to the guide block main body is loaded, and the rotating body is rotated. Guide block body with the desired space on both sides of the guide part being continuous. By performing a forming operation, the guide blocks on both sides can be formed into guide blocks having various desired forming angles with respect to the guide block body portion. Type structure.