JP2001093258A - Reel for magnetic tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reel for a magnetic tape, capable of providing a good magnetic tape winding appearance. SOLUTION: This reel for a magnetic tape is provided with upper and lower reels having flanges in the upper and lower ends of a boss part, on which the magnetic tape is wound, and slopes formed in the inner surfaces of the upper and lower reels toward the outside of a radial direction. In this case, flat surfaces having specified widths are formed in a radial direction orthogonal to the side face of the boss part in the parts of the upper and lower reels adjacent to the boss part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic tape reel used for a magnetic tape cassette such as a digital video cassette (DVC).

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

Tape guides 35 are provided on both sides of the opening 34 on the near side in FIG. 2 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.

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.

A lock pin 54 projects from the side plate 53 of the outer lid 50. The lock pin 54 is provided with a lid lock 55 rotatably provided on the lower cassette half 33.
Is locked. Reference numeral 56 denotes a lid spring that biases these lids to a closed state.

Each of the tape reels 31 has an upper reel 42 and a lower reel 43 facing each other fixed with a predetermined gap between a flange central portion 44 of the upper reel 42 and a boss 45 of the lower reel 43. Be composed.

Referring to FIGS. 2 and 3, each of the tape reels 31 has a pivot hole 46 provided in a flange central portion 44 of an upper reel 42 and a boss portion 45 of a lower reel 43, respectively. The pivot 47 is inserted. A welding boss 48 protruding 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 in the flange central portion 44 of the upper reel 42. 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. This allows
The upper reel 42 and the lower reel 43 facing each other are fixed with a predetermined gap between the flange central portion 44 and the boss portion 45.

Referring to FIGS. 2 and 3, the boss 45 of the lower reel 43 is provided with a side wall 45b, which is a winding surface of the magnetic tape t, around the periphery of the boss 45 radially away from the boss center 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 45, a reference ring 57 serving as a reference for die machining is provided, 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.

As shown in FIG. 3, the inner surface (lower surface) of the upper reel 42 is directed radially outward (the right side in FIG. 3) from the base end (the upper end a in FIG. 3) of the side wall 45b of the boss portion 45. hand,
It is formed as an inclined surface 42b that is gradually inclined upward. The inner surface (upper surface) of the lower reel 43 is radially outward (right side in FIG. 3) from the base end (lower end b in FIG. 3) of the side wall 45b.
Is formed as an inclined surface 43b that gradually decreases toward.

[0015]

However, if the gradient is formed on the entire area of the lower surface of the upper reel and the upper surface of the lower reel as described above, the tape can be wound easily when the magnetic tape is wound, but the magnetic tape is not moved up and down. There is a risk of swinging in the direction.

When a predetermined time elapses after the winding of the magnetic tape, the rotation speed of the reel driving means and the tape tension become constant, and the magnetic tape runs stably, so that the magnetic tape does not swing in the vertical direction. At the start of winding, the rotation speed of the reel driving means gradually increases, and the tape tension also gradually increases, so that tape running is not stable.

Then, the magnetic tape oscillates in the vertical direction, the side edges of the wound magnetic tape do not overlap in an aligned state, and the winding surface formed by the side edges is disturbed and does not become flat.
There is a problem that a good winding appearance cannot be obtained.

An object of the present invention is to solve the above problems and to provide a magnetic tape reel in which a wound magnetic tape has a good winding appearance.

[0019]

SUMMARY OF THE INVENTION The object of the present invention is to provide an upper and lower reel having flanges at upper and lower ends of a boss for winding a magnetic tape, and the inner surfaces of the upper and lower reels are radially outward. In the magnetic tape reel in which a gradient is formed as it goes, a flat surface having a predetermined width in a radial direction orthogonal to a side surface of the boss portion is formed in a portion adjacent to the boss portion of the upper and lower reels. And a magnetic tape reel.

The width of the flat surface in the radial direction is determined by the tape winding thickness from the start of tape winding until the motor speed or the tape tension becomes constant, ie, until the tape winding capability becomes constant. It is preferable that it is above. Specifically, for example, in the case of the above-described DVC, for all sizes of S, M, and L, the width of the horizontal portion in the radial direction is preferably equal to or greater than the thickness of the clamp for fixing the tape to the boss portion.
5 to 5.0 mm is preferred.

The interval between the upper and lower flat surfaces is slightly larger than the width of the magnetic tape, and is made as narrow as possible without interfering with the running of the magnetic tape.

According to the present invention, the flanges around the boss have no gradient and the flanges are parallel to each other, and there is no room for the magnetic tape to move up and down at the start of winding of the magnetic tape. A good winding appearance of the magnetic tape having a uniform winding surface can be obtained.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a half sectional view of a main part of a magnetic tape reel according to an embodiment of the present invention.
The configuration of the present embodiment differs from the conventional magnetic tape reel shown in FIG. 1 only in a part of the configuration. Therefore, the same components are denoted by the same reference numerals and description thereof is omitted or simplified.

The magnetic tape reel shown in FIG. 1 is for a digital video cassette (hereinafter referred to as "DVC") broadcasting station and is of M size. On the inner surface of the flange portion of the upper reel 42, a gradient surface 42b is formed which is inclined upward from the vicinity of the boss portion 45 toward the outside in the radial direction. A slope surface 43b that is inclined downward toward the outside is formed. In addition,
In FIG. 1, the gradient is exaggerated for easy understanding.

The inner surfaces of the flanges of the upper and lower reels 42, 43 are adjacent to the side wall 45b of the boss 45,
Flat surfaces 42c, 43c having a predetermined width W orthogonal to 5b are formed between the side wall 45b and the inclined surfaces 42b, 43b. Both flat surfaces 42c and 43c have a ring shape surrounding the side wall 45b.

The width W of both flat surfaces 42c and 43c is equal,
This width W corresponds to a length equal to or greater than the winding thickness from the start of winding the magnetic tape until the running speed and the tape tension of the magnetic tape become constant and the running of the magnetic tape becomes stable.
The interval H between the flat surfaces 42c and 43c is equal to the side wall 45b.
Equal to the height of the tape, slightly larger than the width of the magnetic tape,
It is made as narrow as possible without impeding the running of the magnetic tape.

In the case of this embodiment, since the reel is an M size DVC reel, the width W of the flat surfaces 42c and 43c is 2.3 mm with respect to the width of the magnetic tape of 6.35 mm.
The interval H between the flat surfaces is 6.7 mm.

The upper and lower inclined surfaces 42b and 43b are flat surfaces 42.
The inclination starts from the boundary parts c and d with c and 43c,
The distance between the upper and lower reels increases toward the outer side in the radial direction, so that the running of the magnetic tape is facilitated.

The magnetic tape is joined to one end of the leader tape, and the other end of the leader tape is fixed to the side wall 45b of the boss 45 by a clamp pin and wound.

Next, the operation of the present embodiment will be described. When the magnetic tape cassette is loaded into a recording / reproducing apparatus or the like and the magnetic tape starts to be wound, the running speed of the magnetic tape gradually increases because the rotation speed of the reel driving means gradually increases in the initial stage of winding. . Also, the tape tension gradually increases as the traveling speed increases. Therefore, in the initial stage of winding of the magnetic tape, the running state is not stable, and there is a possibility that vertical deflection may occur.

However, the magnetic tapes are flat surfaces 42c, 43
In the initial stage of winding around the tape c, the upper and lower side edges of the magnetic tape are regulated by the flat surfaces 42c and 43c of the upper and lower reels. As a result, the side edges are aligned, the winding surface formed by the side edges becomes flat, and a good winding appearance is obtained.

Further, the magnetic tapes are flat surfaces 42c and 43c.
When the tape is wound between the inclined surfaces 42b and 43b beyond the gap, the reel driving means is already rotating at a constant speed, and the tape speed and the tape tension are also stable. Therefore, when the magnetic tape is wound between the inclined surfaces 42b and 43b, there is no possibility that vertical deflection will occur,
There is no fear that the roll will be disturbed. Therefore, the upper and lower reels 4
Good winding appearance of the magnetic tape is obtained over the entire area between 2,43.

Also, the width W of the flat surfaces 42c and 43c is set to 0.
5 to 5.0 mm, interval H between flat surfaces is 6.6 to 6.8 m
If m, a good winding appearance can be obtained as in the above embodiment.

It should be noted that the present invention is not limited to the above-described embodiment, but can be appropriately changed and improved based on the gist of the present invention. For example, the present invention is not limited to DVC, but can be applied to any magnetic tape cassette.

[0035]

As described above, according to the present invention, a flat surface having a predetermined width in the radial direction orthogonal to the side surface of the boss portion is formed in the portion adjacent to the boss portion of the upper and lower reels. During the initial stage of the winding of the magnetic tape between the flat surfaces of the reel, the magnetic tape is described with a flat surface on the side edge, so that there is no risk of vertical deflection. Therefore, the winding surface formed by the side edges of the magnetic tape becomes flat,
Good winding appearance of the magnetic tape is obtained.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a main part of a magnetic tape reel according to an embodiment of the present invention.

FIG. 2 is an exploded view of the magnetic tape cassette.

FIG. 3 is a half sectional view of a conventional magnetic tape reel.

[Explanation of symbols]

 31 Reel for magnetic tape 42 Upper reel 42b Inclined surface 42c Flat surface 43 Lower reel 43b Inclined surface 43c Flat surface 45 Boss 45a Side surface W Width of flat surface H Interval between flat surfaces

Claims (1)

[Claims] 1. A magnetic tape reel comprising upper and lower reels having flanges at upper and lower ends of a boss portion on which a magnetic tape is wound, wherein a gradient is formed on an inner surface of the upper and lower reels in a radially outward direction. 5. The magnetic tape reel according to claim 1, wherein a flat surface having a predetermined width in a radial direction orthogonal to a side surface of the boss portion is formed in a portion of the upper and lower reels adjacent to the boss portion.