JPH1011938A - Tape cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly reliable tape cassette which can accurately detect the tape by providing a rib or a projected part provided as a guide for positioning of a transparent member to an upper case. SOLUTION: Prisms 4 are provided at both ends of the front surface of a transparent window member 3 to be assembled to an upper case 1 to detect the end of tape. In this case, since if this prism 4 has bad molding accuracy and positioning accuracy, such bad accuracy causes malfunction. Therefore, positioning of the prism 4 is executed by a projected part 8 provided on the case 1. However, in order to assure high accuracy, play between this projected part 8 and a recess 18 of the corresponding window 3 is very small. The window 3 is guided by a rib 9 provided at the front surface of the case 1 and a rib 10 provided at the rear surface up to the predetermined position. When the chamfering portion 11 is formed to the upper surface of these ribs 9, 10, assembling can further be done easily. Thereby, when a member 3 is fused to the upper case 1 in the assembling process, the member 3 can be set easily to the predetermined position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape cassette of a digital recording / reproducing system suitable for recording and reproducing a digital signal, for example, a PCM signal, and more particularly to a tape cassette having an optical tape detecting mechanism using a prism. (DA
T).

[0002]

2. Description of the Related Art Conventionally, in a magnetic tape cassette such as a DAT, a method using light is often used as a tape end detecting mechanism. A prism is integrally formed with a transparent window member fixed to a case to detect a tape end. It is provided corresponding to the window. When the prism for tape detection is provided, as shown in FIG. 5, a prism b provided on the upper case a is integrated with the transparent window member c and is located at a position for regulating the XY directions. The d part is a rib or a convex part, and in order to improve the positioning accuracy of the prism,
The play of fitting is also set to be small (actually open flat 5-861).
No. 76), and it is conceivable to provide a prism separately from the window as in Japanese Utility Model Application Laid-Open No. 4-101983 in order to increase the molding accuracy of the prism portion. However, the number of parts and the number of assembly steps associated therewith increase. Therefore, it is desirable that the prism and the window be integrally formed with high precision. In that case, it is known that the gate position of the window is close to the prism and the center of the two prisms is good in order to maintain the accuracy of the prism.

[0003]

However, in the former case of the prior art, when the window member is fused to the upper case in the assembling process, the efficiency of setting the window member at a predetermined position is low (the manual assembly process). ). Also, when an automatic assembling machine is used, it is difficult to set the same for the same reason, and if the accuracy of the automatic assembling machine is poor, there is a problem that the window member cannot be set at a predetermined position. Also, in the latter case, it is best for accuracy to bring the gate closer to the prism, but the mold that forms the prism is 2
It is difficult to bring a gate to this part because it moves inward of one prism because of the mold structure, and if it is further away, there is a problem in the flow direction of the resin, making it impossible to mold the prism accurately. Also, the appearance is bad because gate marks are visible after assembling the cassette. To form the prism with high precision, it is necessary to increase the thickness of the window near the prism.
This is not possible because this is the sliding space for the hub brake. The present invention is intended to solve these problems in the prior art. When the transparent window member and the prism portion are integrally formed, the transparent window member and the prism portion can be formed with high precision. In addition to making it easier to set the window member in the position of, the production efficiency is improved, and the sink of the prism part, which is the final filling, is eliminated and the molding is performed with high accuracy, the positional accuracy of the prism in the window member is stabilized, and the prism is easily and easily formed. It is an object of the present invention to provide a highly reliable tape cassette which can function properly in a tape cassette and can accurately detect a tape.

[0004]

According to the present invention, a pair of hub members each having a tape wound thereon are rotatably supported in a case comprising an upper case and a lower case, and the upper case is provided with a transparent window member. A prism for tape detection is integrally molded with the member,
When the positioning part of the prism is a rib and / or a convex part, XY
In a tape cassette protruding from a position of an upper case that regulates the direction, a rib or a projection serving as a positioning guide of the transparent window member is provided on the upper case.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS When a transparent window member integrally formed with a prism is welded and fixed to a window frame formed in a case in an assembling process, a window member is provided separately from a prism positioning portion provided in the case. With the positioning guide portion, the transparent window member is regulated and fixed, that is, a part of the front-side rib of the upper case and the rear-side rib of the case forming the cutout portion on the front side of the case. When the window member is fused to the upper case in the assembling process, the window member can be easily set at a predetermined position by being configured to guide the window member to the positioning projection provided on the upper case. And the gate of the window member is on the opposite side of the prism across the window,
By increasing the thickness of the gate, the resin can flow more easily, eliminating the sink in the prism, which is the final filling, and forming with high precision.The thicker part can be used as a substitute for the upper sheet retainer rib. Thus, the positional accuracy of the prism with respect to the case is further stabilized.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 to 4. A pair of hub members 5 each having a tape 6 wound thereon are rotatably supported in a case composed of an upper case 1 and a lower case 2. A tape cassette in which a transparent window member 3 is provided, and a prism 4 for detecting the end of the tape is integrally formed with the window member 3.
The ribs 7 and the projections 8 of the positioning portion of the prism 4 are protruded from the case 1 to regulate the XY directions, and the ribs 9 and 10 or the projections serving as positioning guides of the transparent window member 3 are raised. A tape cassette is provided in the case 1.

[0007] The prism positioning section includes:
The linear rib 7 or the convex portion 8 of another shape or any combination thereof is arranged at a position regulating the XY direction, and is brought into contact with both side surfaces of the window member 3 to form the prism 4.
The position accuracy of is improved. In this case, the window member 2 is provided vertically and horizontally on the upper case near the prism formed by the ribs 7 and the projections 8, and is fixed by restricting the X direction and the Y direction of the window member 2. Separately from the prism positioning portion, ribs 9 and 10 or convex portions serving as positioning guides for the window member 3 are provided to face the upper case 1, and a chamfered portion 11 is formed on the ribs 9 and 10 so that the window member can be assembled at the time of assembly. 3 is easy to insert.

The cassette case is configured so that the upper case 1 and the lower case 2 can be screwed together so as to be united. The upper case 1 has a transparent member having a prism 4 and a window member for confirming the remaining amount of the tape. 3, and a pair of hub members 5 around which a magnetic tape 6 is wound are rotatably mounted on the regulating ribs 12 in the cassette case. That is, it has the configuration of the DAT cassette shown in FIGS. The upper and lower cases 1 and 2 are provided with a front lid 13 and a slider 14 and are provided with a seat 15 and a brake 16 interposed therebetween.

As shown in FIGS. 1 and 2, the upper case 1
Prisms 4 and 4 are provided at both ends on the front side of the transparent window member 3 to be assembled, and the end of the tape is detected by the prisms 4. If both the molding accuracy and the positional accuracy of the prism portion 4 are not good, a malfunction may occur. The positioning of the prism portion 4 is performed by the convex portion 8 provided on the upper case 1 because of the cause. However, in order to improve the accuracy, the play between the convex portion 8 and the corresponding concave portion 18 of the window portion 3 is extremely small. Small. Then, as shown in the figure, the window member 3 is guided by the front side rib 9 of the upper case 1 and the rib 10 provided on the back side so that the window member 3 can be assembled at a predetermined position. The upper surfaces of the ribs 9 and 10 have chamfered portions 11.
Is formed, the incorporation is further facilitated. This chamfer may be provided in the window. This facilitates setting the window member 3 at a predetermined position when the window member 3 is fused to the upper case 1 in the assembly process. Note that the rib 10 on the back side can use the side wall of the case. Also, the positioning guide ribs can be provided on the left and right sides of the case.

In order to improve the molding accuracy, the gate position and the fluidity of the resin are taken into consideration.
Wherein the prism 4 In the opposite side of the window portion 3 ₁ a gate portion 21 of the transparent window member 3, the vicinity of the gate portion preferably set to thick portion 20. Therefore, it is possible to eliminate the disadvantage that the flow of the resin becomes poor and the prism portion 4 sinks when the plate thickness of this portion is the same as that of the other portion of the window portion. In other words, the gate portion 21 is formed into a thick portion 20 so that the resin can flow easily, and the sinking of the prism portion 4 which is the final filling can be eliminated so that the molding can be performed with high accuracy. The rib 19 of the upper sheet retainer that has been used can be used as a substitute.

In another embodiment of the present invention, a pair of hub members 5 and 5 around which a tape 6 is wound are provided inside a case including an upper case 1 and a lower case 2, and a transparent window member 3 is mounted on the upper case 1. provided, which has a tape cassette which is integrally formed a prism 4 for tape detection transparent window member 3, there on the side opposite to the prism 4 across the window portion 3 ₁ a gate portion 21 of the transparent window member 3 In addition, it is also effective to eliminate the sink of the prism part, which is the final filling, and to form the prism part with high accuracy by forming the plate part 20 having a large thickness near the gate part 21.

[0012]

According to the present invention, a pair of hub members each having a tape wound thereon are rotatably supported in a case composed of an upper case and a lower case, a transparent window member is provided in the upper case, and the window member has a tape detecting member. A tape cassette in which a prism is integrally formed, and a positioning portion of the prism is protruded from an upper case, and the prism positioning portion is a rib and / or a convex portion and is disposed at a position regulating the XY directions. By providing the upper case with ribs or protrusions that serve as positioning guides for the window member separately from the prism positioning portion, it is possible to set the window member at a predetermined position when fusing the window member to the upper case in the automatic assembly process. make it easier. In addition, even a small-volume prism can always be kept in an accurate positional relationship in the case, guaranteeing stable operation, greatly improving reliability, and simplifying the assembling process to improve productivity. Further, in a tape cassette in which a prism for tape detection is integrally formed with a transparent window member, the gate of the window member is on the opposite side to the brhythm with the window portion interposed therebetween, and by increasing the thickness of the gate portion,
It is easy to flow the resin at the time of molding, eliminating the sink of the prism part that will be the final filling, and molding with high precision.The presence of the thick part ensures that the sheet is held securely, the tape running is stable and the quality can be greatly improved. effective.

[Brief description of the drawings]

FIG. 1 shows the inner surface of an upper case showing an embodiment of the present invention,
(A) is a plan view thereof, (b) is an enlarged vertical sectional view taken along line AA, and (c) is an enlarged vertical sectional view taken along line BB.

2A and 2B show a window member of the example of FIG. 1, wherein FIG. 2A is a plan view, FIG. 2B is a front view, and FIG. 2C is a side view.

FIGS. 3A and 3B show a use state of the example of FIG. 1, wherein FIG. 3A is a plan view thereof, and FIG. 3B is a longitudinal sectional view taken along line CC.

FIG. 4 is a perspective view showing the disassembled state of the present invention.

FIG. 5 is a plan view of an upper case showing a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 upper case 2 lower case 3 window member 4 prism 5 hub member 6 tape 7 positioning rib 8 positioning protrusion 9 guide rib 10 guide rib 11 chamfered portion 12 regulating rib 18 concave portion 19 sheet holding rib 20 plate thickness portion 21 gate portion

Claims (3)

[Claims] 1. A pair of hub members each having a tape wound thereon are rotatably supported on a case composed of an upper case and a lower case,
A transparent window member is provided on the upper case, and a prism for tape detection is integrally formed on the window member, and a positioning portion of the prism is provided so as to protrude at a position of the upper case which regulates the XY directions by ribs and / or protrusions. A tape cassette, characterized in that a rib or a projection serving as a guide for positioning the transparent window member is provided in an upper case. 2. The tape cassette according to claim 1, wherein the gate of the transparent window member is on the opposite side of the window with respect to the prism, and the vicinity of the gate portion is a thick plate portion. 3. A pair of hub members each having a tape wound thereon are rotatably supported on a case composed of an upper case and a lower case,
In a tape cassette in which a transparent window member is provided in an upper case, and a prism for tape detection is integrally formed with the window member, a gate of the transparent window member is on the opposite side of the prism with respect to the window portion and is near the gate portion. A tape cassette characterized in that it is formed in a thick plate portion having a large plate thickness.