JP2000293968A - Magnetic tape cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten welding times of respective bosses for weld and to enhance welding stability of the bosses by unformly raising transmission efficiency to respective bossess for weld of the oscillation energy of ultrasonic waves. SOLUTION: Respective ribs 23 connecting a boss center part 21 and a side wall are respectively provided at arrangements respectively corresponding to arrangements of bosses for weld 20. The rib 23 of a right side among respective ribs 23 is exposed to the outer surface side of the side wall with a notched part 26 which is installed by notching one part of the peripheral direction of the side wall to constitute a clamping part 27 to which the base end part of a magnetic tape which is to be wound around the side wall is to be fixed. That is, the rib 23 of the right side constituting the clamping part 27 and two other ribs 23 are made to have the same constitution and also the ribs are arranged for every 120 degrees in the peripheral direction around a pivot 19 in the boss center part 21 and they are made to have phase differences of every 60 degrees in the peripheral direction around the pivot 19 with respect to bosses for weld 20.

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 efficiently performing ultrasonic welding of a boss for welding a tape reel.

[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. 6, a pair of tape reels 31 wound with a magnetic tape t is wound in a lower cassette half 33 paired with an upper cassette half 32 as a magnetic tape cassette 30 conventionally used for DVC, for example. Some are movably supported.

[0006] Tape guides 35 are provided on both sides of an opening 34 on the near side in FIG. 6 of the lower cassette half 33. 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, in each of the tape reels 31, a pivot 47 projecting from the boss 45 of the lower reel 43 is inserted into a pivot hole 46 provided in the flange 44 of the upper reel 42. 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. It is inserted into the welding boss hole 49. 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. As a result, the upper reel 42 facing the
The lower reel 43 is fixed with a predetermined gap between the flange 44 and the boss 45.

Referring to FIGS. 6 to 8, the boss portion 45 of the lower reel 43 is provided with a side wall 45b, which is a winding surface of the magnetic tape t, provided around a radial direction away from the boss center portion 45a. Between the central portion 45a and the side wall 45b and between the base end portion 48a of the welding boss 48 and the side wall 45b,
The boss portion 45 is connected by a plurality of (seven in FIG. 8) connecting ribs 57 along the radial direction, and the boss center portion 45a and the side wall 45b are connected by a rib 58 having a required shape.

The pivot 47 protrudes from the center of the upper surface of the boss center 45a. A plurality (three in FIG. 8) of welding bosses 48 are provided on the upper surface of the boss center portion 45a at predetermined intervals in the circumferential direction.

The rib 58 is provided at the welding boss 48 at the center in FIG.
And the welding boss 48 on the right side in FIG. 8, and is disposed between the boss center portion 45a and the side wall 45b. The rib 58 is a concave rib 58a formed in a concave shape in plan view and opened to the side wall 45b side, and a linear rib formed between the concave rib 58a and the boss center 45a along the radial direction from the boss center 45a. 58b. Rib 58
Is a notch portion 45 obtained by cutting out a part of the side wall 45b in the circumferential direction.
The opening side of the concave rib 57a is exposed to the outer surface side of the side wall 45b through c, and forms a clamp portion 59 to which the base end of the magnetic tape t wound around the side wall 45b is fixed.

[0011]

In the conventional magnetic tape cassette 30 described above, when each welding boss 48 is ultrasonically welded, transmission of ultrasonic oscillation energy from the welding horn at each welding boss 48 is performed. There has been a problem that the efficiency varies and the welding stability is poor. Further, since the clamp portion 59 is provided only in a part, the balance at the time of molding is poor, and the roundness of the reel is poor.

That is, in the welding bosses 48 on the right and upper sides in FIG. 8, the oscillating energy of ultrasonic waves from the welding horn is effectively transmitted due to the high rigidity of the ribs 58 constituting the clamp portion 59, and A stable welding is achieved.

On the other hand, the welding boss 48 on the left side in FIG.
Ultrasonic oscillation energy from the welding horn is dispersed to other parts of the lower reel 43 via, for example, the connecting rib 57 between the base end 48a of the welding boss 48 and the side wall 45b. For this reason, the transmission efficiency of the ultrasonic oscillation energy from the welding horn to the welding boss 48 is low, so that there is a problem that welding takes time and welding stability is lacking. If only the welding boss 48 on the left side in FIG. 8 lacks welding stability, the facing posture of the upper reel 42 and the lower reel 43 may be distorted, which may cause a surface runout when the tape reel 31 rotates. I will.

In view of such circumstances, the present invention can uniformly increase the transmission efficiency of ultrasonic oscillation energy to each welding boss, thereby shortening the time required for ultrasonic welding of each welding boss and welding. It is an object of the present invention to provide a magnetic tape cassette provided with a tape reel capable of improving stability.

[0015]

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. A plurality of welding bosses respectively protruded are fitted into a plurality of welding boss holes provided on the flange portion of the upper reel, and in this state, each welding boss is ultrasonically welded, In a magnetic tape cassette provided with a tape reel to which the upper reel and the lower reel are fixed, a boss portion of the lower reel is provided with the pivot and the welding boss, respectively. A central portion between the welding bosses at the center of the boss and a side wall provided around the radially distant from the center of the boss and serving as a winding surface of the magnetic tape. A concave rib that is formed in a concave shape that opens on the side wall side is provided, and one of the concave ribs is a notch formed by cutting out a part of the side wall in a circumferential direction. A magnetic tape cassette provided with a tape reel, characterized in that the magnetic tape cassette comprises a clamp portion exposed to the outer surface side of the side wall through the portion and fixing an end of the magnetic tape.

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

The concave ribs, one of which constitutes a clamp portion, are respectively provided between the center between the welding bosses and the side wall. Thus, when each welding boss is ultrasonically welded, the ultrasonic oscillation energy acting on each welding boss is evenly and efficiently transmitted, so that it is dispersed to other portions of the lower reel. Can be reliably prevented. Therefore, the ultrasonic oscillation energy is effectively transmitted to each welding boss, and stable ultrasonic welding can be performed.

[0018]

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. FIG. 3 is a perspective view showing a lower reel of the tape reel of the magnetic tape cassette of FIG.
Is a plan view of the lower reel of FIG. 3, and FIG. 5 is an enlarged plan view of a main part of the lower reel of FIG.

In FIG. 1, a magnetic tape cassette 10
Shows a pair of tape reels 12 wound around a magnetic tape t (see FIG. 6) (a tape reel on the right side in the figure is not shown).
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 is integrally formed of a transparent synthetic resin to check the remaining amount of the tape.
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.

Referring to FIGS. 1 to 5, the lower reel 16 has a pivot 19 and a welding boss 20 projecting from the upper surface of the boss portion 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. Shaped rib 2
3, the base end 25 and the side wall 22 of the welding boss 20 are connected by connecting ribs 24.

The pivot 19 projects from the center of the upper surface of the boss center 21. Further, a plurality of welding bosses 20 are protruded from the upper surface of the boss center portion 21 at predetermined intervals (in this embodiment, three bosses 20 are provided at every 120 ° in the circumferential direction around the pivot 19). Is done.

Each rib 23 is provided with each welding boss 20.
Are provided in an arrangement corresponding to the arrangement. That is, as particularly shown in FIGS. 4 and 5, each of the ribs 23 is formed between the concave rib 23 a and the boss center 21 which are formed in a substantially concave shape in plan view and open to the side wall 22 side. And a linear rib 23b formed radially from the boss center 21. Each rib 23 is disposed between the center between the welding bosses 20 at the boss center portion 21 and the side wall 22.

The ribs 23 on the right side in FIG.
Is formed such that the opening side of the concave rib 23a is exposed to the outer surface side of the side wall 22 through a notch 26 formed by cutting a part of the side wall 22 in the circumferential direction. The clamp part 27 to which the base end is fixed is constituted. That is, the right rib 23 in FIG.
And the other two ribs 23 have substantially the same configuration, and are arranged at intervals of 120 ° in the circumferential direction around the pivot 19 at the boss center portion 21.
A phase difference of 60 ° was provided in the circumferential direction around the pivot 19.

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 this embodiment will be described. When each welding boss 20 is ultrasonically welded, when each welding horn is brought into contact with the distal end surface of each welding boss 20, the ultrasonic oscillation energy is transmitted from each welding horn to the distal end surface of each welding boss 20. It is transmitted to almost the center.

At this time, ribs 23 composed of the same number of concave ribs 23a and linear ribs 23b as the welding bosses 20 are provided between the boss center portion 21 and the side walls 22 in an arrangement corresponding to the arrangement of the welding bosses 20, respectively. By being provided, the ultrasonic oscillation energy is transmitted from each welding horn to each welding boss 20 evenly and efficiently without diffusing to other parts of the boss portion 15. The welding bosses 20 are uniformly and ultrasonically welded in a short time by the transmitted ultrasonic oscillation energy.

As described above, according to the above-described embodiment, the ribs 23 composed of the concave ribs 23a and the linear ribs 23b are provided between the boss center portions 21 and the side walls 22.
Are provided between the center between the welding bosses 20 in the boss center portion 21 and the side wall 22. The rib 2 on the right side in FIG.
3 is a concave rib 23a through a notch 26 in the side wall 22.
The opening side of the magnetic tape t is exposed to the outer surface side of the side wall 22 to form a clamp portion 27 to which the base end of the magnetic tape t is fixed. That is, the rib 23 on the right side in FIG. 5 and the other two ribs 23 constituting the clamp portion 27 have substantially the same configuration, and the boss center portion 21 is formed at every 120 ° in the circumferential direction around the pivot 19. The welding bosses 20 were arranged so as to have a phase difference of 60 ° around the pivot 19 in the circumferential direction.

Therefore, the transmission efficiency of the ultrasonic oscillation energy from the welding horn to each welding boss 20 can be uniformly increased without variation among the welding bosses 20.
As a result, the time required for ultrasonic welding of the welding bosses 20 can be greatly reduced, and the welding stability can be improved.
6 can be properly maintained, and surface runout or the like during rotation of the tape reel 12 can be reliably prevented.

[0031]

As described above, according to the present invention, between the center between the welding bosses at the center of the boss and the side wall, the concave rib formed in the side of the side wall is provided. In addition, one of the concave ribs is exposed to the outer surface of the side wall through a cut-out part of which is cut off in the circumferential direction of the side wall, and forms a clamp part to which the end of the magnetic tape is fixed. . Therefore, the transmission efficiency of the ultrasonic oscillation energy to each welding boss can be uniformly increased. Thereby, the time required for ultrasonic welding of each welding boss can be reduced and the welding stability can be improved. Further, by providing the same rib as the clamp portion, the balance at the time of molding is improved, and the roundness of the reel is also improved.

[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 a perspective view showing a lower reel of a tape reel of the magnetic tape cassette of FIG. 1;

FIG. 4 is a plan view of a lower reel of FIG. 3;

FIG. 5 is an enlarged plan view of a main part of a lower reel of FIG. 4;

FIG. 6 is an exploded perspective view of a conventional magnetic tape cassette.

FIG. 7 is a perspective view showing a lower reel of the tape reel of the magnetic tape cassette of FIG. 6;

FIG. 8 is a plan view of a lower reel of FIG. 7;

[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 central part 22 Side wall 23 Rib 23a Concave rib 23b Straight -Shaped rib 24 Connecting rib 25 Base end 26 Notch 27 Clamp 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,
A plurality of welding bosses projecting from the boss portion of the lower reel are inserted into the boss portion of the lower reel. A tape reel to which the upper reel and the lower reel were fixed by being fitted and inserted into a plurality of welding boss holes provided on the flange portion, and by welding each welding boss in this state by ultrasonic welding. In the magnetic tape cassette, the boss portion of the lower reel is provided around a boss center portion that protrudes the pivot and each of the welding bosses, and is provided in a periphery radially away from the boss center portion. A center between the welding bosses at the center of the boss and the side wall, and formed in a concave shape opening toward the side wall. And one of the concave ribs is exposed to the outer surface side of the side wall through a cutout partly notched in the circumferential direction of the side wall. A magnetic tape cassette having a tape reel, wherein the magnetic tape cassette constitutes a clamp unit for fixing the unit.