JP2000293967A - Magnetic tape cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a contact between a lower reel and a lower cassette half by preparing a tilted surface which gradually tilts toward an upper reel and toward the radial outside from a reference ring on a surface set opposite to the boss part of the lower reel. SOLUTION: A reference ring 25 serving as a metal mold machining standard is placed on the bottom surface 24 of a lower reel 16 set opposite to the boss part 15 of the reel 16, and a tilted surface 24b gradually tilts toward an upper reel 14 and toward the radial outside in a place radially outward from the ring 25. A >=0.2 mm difference H is produced in the depth direction of the reel 16 having a diameter of 100 mm, for example, between the radial inside and outside ends on the surface 24b, Thus, it is possible to prevent the contact between the outer fringe part of the surface 24 in particular and the inner surface of a lower cassette half even when the reel 16 swings within its allowable swing range by the vibrations of a magnetic tape cassette 10, for example, caused when it is carried about.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape reel of a magnetic tape cassette such as a digital video cassette (DVC), and more particularly to a structure for preventing a lower reel of a tape reel from contacting an inner surface of a lower cassette half.

[0002]

2. Description of the Related Art In general, in audio equipment, video equipment and the like, a magnetic tape cassette for recording / reproducing a magnetic tape wound around a pair of tape reels so as to be able to run in a cassette half is often used. . Referring to FIG. 3, a pair of tape reels 31 around which a magnetic tape t is wound, as a magnetic tape cassette 30 conventionally used for, for example, a DVC, is wound in a lower cassette half 33 paired with an upper cassette half 32. Some are movably supported.

Tape guides 35 are provided on both sides of an opening 34 on the near side in FIG. 3 of the lower cassette half 33, respectively. Each tape guide 35 is sent from one tape reel 31 to the other tape reel 31.
And guides the magnetic tape t to pass through a predetermined position in the opening 34.

On the rear side of the lower cassette half 33, a reel lock member 39 having a tape reel locking arm 38 is provided. Reel lock member 39
Is urged by a compression coil spring 40 to move the tape reel locking arm 38 to each tape reel 3.
The tape reel 31 is engaged with the engaging teeth 41 formed on the outer circumference of the tape reel 1 to prevent the tape reels 31 from being accidentally rotated. This prevents loosening of the magnetic tape t.

[0005] An outer lid 50, a top lid 52, and an inner lid 51 that cover the opening 34 of the lower cassette half 33 are respectively attached to the upper cassette half 32 so as to be freely opened and closed. Side plate 53 of outer lid 50
, A lock pin 54 is protruded. Lock pin 54
Is locked by a lid lock 55 rotatably provided on the lower cassette half 33. Reference numeral 56 denotes a lid spring that biases these lids to a closed state.

Each of the tape reels 31 is constituted by fixing an upper reel 42 and a lower reel 43 facing each other with a predetermined gap between a flange portion 44 of the upper reel 42 and a boss portion 45 of the lower reel 43. Is done.

That is, referring to FIG. 3 and FIG. 4, each tape reel 31 has a pivot hole 46 provided in a flange portion 44 of an upper reel 42 and a boss portion 45 of a lower reel 43 projecting therefrom. The pivot 47 is inserted. Further, a welding boss 48 projecting from the boss portion 45 of the lower reel 43 at a position radially away from the pivot 47 is provided at a position corresponding to the welding boss 48 on the flange portion 44 of the upper reel 42. Welding boss hole 4
9 is inserted. In this state, the welding boss 48 is ultrasonically welded by bringing a welding horn (not shown) into contact with substantially the center of the distal end surface of the welding boss 48. Thereby, the upper reel 42 and the lower reel 43 facing each other are fixed with a predetermined gap between the flange portion 44 and the boss portion 45.

Referring to FIGS. 3 to 5, the boss portion 45 of the lower reel 43 is provided with a side wall 45b serving as a winding surface of the magnetic tape t around the radially distant portion from the boss center portion 45a. The central portion 45a and the side wall 45b are connected by a plurality of ribs 57 along the radial direction of the boss portion 45.

The pivot 47 protrudes from the center of the upper surface of the boss center 45a. A plurality of welding bosses 48 are provided on the upper surface of the boss center portion 45a at predetermined intervals in the circumferential direction.

On the bottom surface 43a of the lower reel 43 opposite to the boss portion 45, a reference ring 57 is provided as a reference for die machining, and an inner ring 58 is provided radially inward of the reference ring 57. Reference ring 57 and inner ring 5
Numerals 8 are located at predetermined positions radially away from the pivot 47 with respect to the welding boss 48.

The bottom surface 43a of the lower reel 43 has a portion between the reference ring 57 and the inner ring 58 and the reference ring 5
A portion between the outer peripheral portion and the outer peripheral portion is formed on the same horizontal plane. On the other hand, the upper surface 43b of the lower reel 43
The side wall 45b is formed as an inclined surface that is gradually inclined downward from the base end (the lower end in FIG. 5) toward the outside in the radial direction (the right side in FIG. 5). When the magnetic tape cassette 30 is not loaded in a driving device (not shown), the lower reel 43 is provided near the radially outer side of the reference ring 57 on the bottom surface 43 a and is provided with a projection 3 protruding from the lower cassette half 33.
3a is abutted and is supported in a predetermined posture.

[0012]

In the above-described conventional magnetic tape cassette 30, the lower reel 43 has, for example, a diameter of 1 mm.
The size is about 00mm, in the thickness direction (vertical direction in FIG. 5)
Has an allowable runout width of about 0.2 mm. Therefore, when the magnetic tape cassette 30 is not used, that is, when the magnetic tape cassette 30 is carried, for example, the lower reel 43 is not used.
Swings within the allowable swing width. For this reason, the lower reel 4
3 radially outward (particularly the outer edge) from the contact position of the bottom surface 43a of the third cassette half 33 with the projection 33a.
However, there is a problem that the inner surface of the lower cassette half 33 is intermittently contacted, and each part of the magnetic tape cassette 30 is scratched, worn, and dusted.

In view of such circumstances, the present invention can prevent the lower reel from coming into contact with the inner surface of the lower cassette half even when the lower reel swings within the allowable swing width when the magnetic tape cassette is not used, for example. Accordingly, it is an object of the present invention to provide a magnetic tape cassette provided with a tape reel that can prevent scratches, abrasion, dusting, and the like of each part.

[0014]

An object of the present invention is to provide an upper reel having a flange portion, and a lower reel having a boss portion on a surface facing the upper reel and facing the upper reel. And a pivot hole provided in a flange portion of the upper reel is fitted with a pivot projecting from a boss portion of the lower reel, and at a position radially away from the pivot in the boss portion of the lower reel. The projecting welding boss is fitted into the welding boss hole provided in the flange portion of the upper reel, and the welding boss is ultrasonically welded in this state, whereby the upper reel and the lower reel are welded. A magnetic tape cassette provided with a tape reel to which a reference ring is provided on a surface of the lower reel opposite to the boss portion, and a surface of the lower reel opposite to the boss portion. The radially outer than the reference ring definitive, is achieved by a magnetic tape cassette having a tape reel, characterized in that the inclined surface inclined gradually to the upper reel side toward the radially outer side is provided. Here, such an inclined surface may be linear or have a curvature, or a part thereof may be a step.

In the tape reel of the magnetic tape cassette according to the present invention, a pivot projecting from a boss of the lower reel is inserted into a pivot hole provided in a flange of the upper reel. Further, a welding boss protruding from the boss portion of the lower reel at a position radially away from the pivot is fitted and inserted into a welding boss hole provided on the flange portion of the upper reel. In this state, the welding boss is ultrasonically welded. As a result, the upper reel and the lower reel are fixed in a predetermined positional relationship.

On the surface of the lower reel opposite to the boss portion, an inclined surface is provided radially outward from the reference ring and gradually inclined toward the upper reel toward the radial outside. Therefore, for example, when the magnetic tape cassette is not loaded in the driving device and is not used, even if the lower reel swings within the allowable swing width due to the influence of vibration or the like, it is possible to prevent the lower reel from contacting the inner surface of the lower cassette half.

The radially inner end and the radially outer end of the slope are 0.2 m along the thickness direction of the lower reel.
Preferably, there is a difference of at least m.

Further, it is preferable that the thickness of the lower reel in a portion radially outward of the reference ring is set to a predetermined value or more. By setting in this manner, the thickness of the lower reel, particularly in the vicinity of the outer edge portion, is prevented from being reduced due to the provision of the inclined surface, and the swing of the lower reel within the allowable swing width does not become unstable.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a plan view showing a lower cassette half of a magnetic tape cassette to which a tape reel according to an embodiment of the present invention is applied, and FIG. 2 is a diagram showing upper and lower reels of the tape reel of the magnetic tape cassette of FIG. It is a fragmentary sectional view.

In FIG. 1, a magnetic tape cassette 10
Shows a pair of tape reels 12 (a tape reel on the right side is not shown in the figure) around which a magnetic tape t (see FIG. 3) is wound.
It is rotatably supported by a lower cassette half 11 that forms a pair with an upper cassette half (not shown). The lower cassette half 11 is integrally formed of a synthetic resin such as an ABS resin.

Referring to FIGS. 1 and 2, each of the tape reels 12 of the magnetic tape cassette 10 has an upper reel 14 having a flange portion 13 and a surface facing the upper reel 14 and facing the upper reel 14. And a lower reel 16 having a boss 15. The upper reel 14 and the lower reel 16 are fixed with a predetermined gap between the lower surface of the flange 13 of the upper reel 14 and the upper surface of the boss 15 of the lower reel 16. The upper reel 14 is integrally formed of synthetic resin from the viewpoint of checking the remaining amount of tape, and the lower reel 16
Is integrally formed of an opaque synthetic resin.

The upper reel 14 is provided with a pivot hole 17 and a welding boss hole 18. The pivot hole 17 is provided through the center of the flange portion 13 of the upper reel 14.
The welding boss holes 18 are provided in the flange portion 13 of the upper reel 14 at positions corresponding to the welding bosses 20 described later, and are provided in the same number as the welding bosses 20.

The lower reel 16 has an outer edge (right end in FIG. 2).
Further, a gear portion 16a is provided to be fitted with a brake (not shown) for preventing inadvertent reel rotation. Lower reel 1
Numeral 6 is, for example, about 100 mm in diameter and has an allowable swing width of about ± 0.2 mm in the thickness direction (vertical direction in FIG. 2).

The lower reel 16 has a pivot 19 and a welding boss 20 projecting from the upper surface of the boss 15 respectively. The boss portion 15 is provided with a side wall 22 serving as a winding surface of the magnetic tape t around a radial direction away from the boss center portion 21, and furthermore, the boss center portion 21 and the side wall 22 are formed by a plurality of ribs 2.
3 and are connected.

The pivot 19 protrudes substantially at the center of the upper surface of the boss center portion 21. In addition, a plurality of welding bosses 20 are provided on the upper surface of the boss center portion 21 at predetermined intervals (in this embodiment, a total of three bosses are provided at every 120 ° in the circumferential direction around the pivot 19). You.

On the bottom surface 24 of the lower reel 16 opposite to the boss 15, a reference ring 25 serving as a reference for die machining is provided, and an inner ring 26 is provided radially inward of the reference ring 25. . The reference ring 25 and the inner ring 26 are each located at a predetermined radial distance from the pivot 19 with respect to the welding boss 20.

The bottom surface 24 of the lower reel 16 is
5 and the inner ring 26, the horizontal plane 24 in FIG.
a, and a portion between the reference ring 25 and the outer edge portion is a base end portion of the reference ring 25 (an upper end portion in FIG. 2).
2 is formed as an inclined surface 24b that is gradually inclined upward with a predetermined inclination angle from the radial direction outward (to the right in FIG. 2). In the inclined surface 24b, the diameter of the lower reel 16 is, for example, 100 m between the radial inner end and the radial outer end.
m, there is a difference H of 0.2 mm or more along the thickness direction of the lower reel 16 (vertical direction in FIG. 2).

On the other hand, the upper surface 27 of the lower reel 16 is
2 is formed as an inclined surface that is gradually inclined downward from the base end (the lower end in FIG. 2) toward the outside in the radial direction (the right side in FIG. 2). The inclination angle of the inclined surface is substantially half that of the conventional one shown in FIG.
The thickness of the portion outside the reference ring 25 in the radial direction is set to a predetermined value or more.

In each tape reel 12,
A pivot 19 projecting from the boss 15 of the lower reel 16 is fitted into a pivot hole 17 provided in the flange 13 of the upper reel 14. Also, the boss 15 of the lower reel 16
The welding boss 20 projecting from the upper reel 14 is inserted into a welding boss hole 18 provided in the flange portion 13 of the upper reel 14.
In this state, each welding boss 20 is ultrasonically welded by bringing a welding horn (not shown) into contact with the approximate center of the tip surface (the upper end surface in FIG. 2) of each welding boss 20. As a result, the upper reel 14 and the lower reel 16 are fixed in a predetermined positional relationship.

The operation of the present embodiment will be described. When the magnetic tape cassette 10 is not loaded in the drive unit and is not used, that is, when the magnetic tape cassette 10 is carried, for example, even if the lower reel 16 of the tape reel 12 swings within the allowable swing width due to the influence of the vibration, the bottom surface of the lower reel 16 An inclined surface 2 provided radially outward from the reference ring 25 at 24 and gradually inclined toward the upper reel 14 outward in the radial direction.
4b prevents the bottom surface 24 of the lower reel 16 from contacting, in particular, the outer edge and the inner surface of the lower cassette half 11.

As described above, according to the above-described embodiment, the inclined surface 24b is provided on the bottom surface 24 of the lower reel 16 radially outward from the reference ring 25 and gradually inclined toward the upper reel 14 outward in the radial direction. Can be Also, inclined surface 2
4b at the radially inner end and the radially outer end,
The lower reel 16 having a diameter of 100 mm has a difference of 0.2 mm or more along the thickness direction of the lower reel 16. Therefore, even if the lower reel 16 swings within the allowable swing width due to, for example, the vibration of the magnetic tape cassette 10 when it is carried, the outer edge of the bottom surface 24 of the lower reel 16 particularly contacts the inner surface of the lower cassette half 11. Can be prevented. Thereby, it is possible to prevent scratches, abrasion, dusting, and the like of each part of the magnetic tape cassette 10, and it is possible to improve durability.

The upper surface 27 of the lower reel 16 is formed so as to be nearly horizontal with an inclination angle substantially half that of the conventional inclined surface shown in FIG. The thickness of the radially outer portion is set to a predetermined value or more. Therefore, it is possible to prevent the thickness of the lower reel 16, particularly in the vicinity of the outer edge portion, from being reduced by providing the inclined surface 24 b on the bottom surface 24. 16 can be prevented from becoming unstable due to the thickness particularly near the outer edge.

The present invention is not limited to the above-described embodiment, and can be appropriately changed and improved. For example, in the above-described lower reel, an inclined surface that is gradually inclined toward the upper reel side outward in the radial direction from the base end of the reference ring in the radial direction is formed, but only the vicinity of the gear portion is formed. It may be an inclined surface inclined toward the upper reel.

[0034]

As described above, according to the present invention, on the surface opposite to the boss portion of the lower reel, radially outward from the reference ring, the inclination gradually inclined toward the upper reel toward the radially outward side. A surface is provided. Therefore, for example, even when the magnetic tape cassette is not loaded in the drive device and is not used, even if the lower reel swings within the allowable swing width, it is possible to prevent the lower reel from contacting the inner surface of the lower cassette half.
As a result, it is possible to prevent scratches, abrasion, dusting, and the like of each part of the magnetic tape cassette.

[Brief description of the drawings]

FIG. 1 is a plan view showing a lower cassette half of a magnetic tape cassette to which a tape reel according to an embodiment of the present invention is applied.

FIG. 2 is a sectional view of a main part showing upper and lower reels of a tape reel of the magnetic tape cassette of FIG. 1;

FIG. 3 is an exploded perspective view of a conventional magnetic tape cassette.

FIG. 4 is a sectional view of a main part showing upper and lower cassette halves and a tape reel of the magnetic tape cassette of FIG. 3;

FIG. 5 is a sectional view of a main part showing upper and lower reels of a tape reel of the magnetic tape cassette of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Magnetic tape cassette 11 Lower cassette half 12 Tape reel 13 Flange part 14 Upper reel 15 Boss part 16 Lower reel 17 Pivot hole 18 Welding boss hole 19 Pivot 20 Welding boss 21 Boss center part 22 Side wall 23 Rib 24 Bottom of lower reel 24a Horizontal surface 24b Inclined surface 25 Reference ring 26 Inner ring 27 Upper surface of lower reel t Magnetic tape

Claims (1)

[Claims] 1. An upper reel having a flange portion, and a lower reel disposed opposite to the upper reel and having a boss on a surface facing the upper reel, the lower reel being provided on a flange portion of the upper reel. The pivot hole,
Along with inserting a pivot projecting from the boss of the lower reel, a welding boss projected radially away from the pivot in the boss of the lower reel is attached to the flange of the upper reel. In the magnetic tape cassette having a tape reel to which the upper reel and the lower reel are fixed by being inserted into the provided welding boss hole and ultrasonic welding the welding boss in this state, A reference ring is provided on the surface of the reel opposite to the boss portion, and the radially outward of the reference ring on the surface of the lower reel opposite to the boss portion is gradually radiated outward. A magnetic tape cassette provided with a tape reel, wherein an inclined surface is provided on an upper reel side.