JPS6134378Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a magnetic tape reel such as a reel used in a magnetic tape cartridge for a VTR, an endless magnetic tape cartridge, or a reel used as an open reel.

Conventional open reels have multiple large fan-shaped openings formed in the flange of the reel along the circumferential direction of the reel, expanding from the inner circumference to the outer circumference, in order to reduce weight and improve appearance. There is. However, when winding the magnetic tape onto this reel at high speed, or when feeding out the magnetic tape wound on the reel at high speed, the flange of the reel swings vertically due to the large fan-shaped opening mentioned above. Therefore, the magnetic tape is not wound evenly,
The end faces of the magnetic tape winding layer become uneven, causing damage to the tape edges and adversely affecting recording and reproducing characteristics.

On the other hand, reels used in magnetic tape cartridges for VTRs and the like do not have openings or through holes in their flange portions. Therefore, when winding the magnetic tape at high speed or feeding it out at high speed, there is no large vibration like with the open reel mentioned above.
As expected, the winding condition of the magnetic tape is poor.

As a result of various studies on this point, the inventor of the present invention found that
We discovered the following. In other words, if there is no opening (through hole) that passes through the flange from the inner surface to the outer surface, when winding the magnetic tape onto a reel, the magnetic tape that has already been wound and the magnetic tape that will be wound next Since there is a flange on the outside, the air between the two parts has no place to escape and gets drawn in together. Therefore, air accumulates between the layers of the wound magnetic tape, and as the winding force of the magnetic tape gradually increases, the accumulated air is forced out by the pressure, or due to the air bearing effect, A portion of the magnetic tape shifts in the axial direction of the tape winding layer, causing winding irregularities. This tendency is caused by the fact that when winding a magnetic tape at high speeds, such as during fast forwarding or rewinding, there is a lot of air being drawn in, and the winding is noticeably disturbed.

The present invention was developed in view of these points, and includes a hub part around which a magnetic tape is wound, and a magnetic tape connected to at least one of the upper and lower ends of the hub part in the radial direction of the hub part. In a magnetic tape reel having a flange portion extending outward, a plurality of sector-shaped recesses expanding from the inner circumferential portion toward the outer circumferential portion are provided in the circumferential direction on the inner surface side of the flange portion, and the inner circumferential portion of the recess The flange is characterized by having a through hole for air release penetrating from the bottom of the concave portion to the outer surface of the flange on the side of the outer periphery from the center point between the flange and the outer periphery.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partially sectional front view of a magnetic tape reel used in a VTR magnetic tape cartridge according to an embodiment, FIG. 2 is a plan view of the reel with the upper flange removed, and FIG. FIG. 3 is an explanatory diagram showing the state of air flow when winding the magnetic tape onto the reel.

As shown in FIG. 1, the magnetic tape reel is mainly composed of a hub part 1, a lower flange part 2, and an upper flange part 3. The hub part 1 and the lower flange part 2 are integrally molded, and the upper flange part 3 is fixed to the upper end of the hub portion 1 so as to be parallel to the lower flange portion 2. The magnetic tape 4 is wound around the outer periphery of the hub portion 1 and is housed between the lower flange portion 2 and the upper flange portion 3.

As shown in FIG. 2, on the inner surface of the lower flange portion 2, that is, on the side facing the magnetic tape 4 being wound, there is a fan-shaped recess 5 that expands from the inner circumference toward the outer circumference of the reel. A plurality of, for example, nine, are formed along the radial direction. Thick radial ribs 6 extending in the radial direction are provided between the recesses 5 , and thick circumferential ribs 7 are provided on the outer periphery of the lower flange portion 2 . The directional ribs 6 and the circumferential ribs 7 are continuous. Each recess 5 has a recess 5
A through hole 10 is formed extending from the bottom surface 8 of the lower flange portion 2 to the outer surface 9 of the lower flange portion 2 . This through hole 10
is an elongated hole extending in the circumferential direction of the lower flange portion 2 and is provided at a position slightly closer to the outer circumferential side than the center point between the inner circumferential portion and the outer circumferential portion of the concave portion 5. The mouth widens towards the side. Note that the size of the through hole 10 needs to be kept to an extent that the lower flange portion 2 does not swing when the reel is rotated at high speed.

Similarly to the lower flange portion 2, the upper flange portion 3 is also provided with a recess 5, a radial rib 6, a circumferential rib 7, and a through hole 10, respectively.

When winding the magnetic tape 4 around the tape reel of the present invention constructed as described above, as shown in FIG. Air 11 between the magnetic tape 4 and the magnetic tape 4 is collected in recesses 5 located at both the upper and lower ends of the magnetic tape 4. Here, as described above, since the recess 5 has a fan shape expanding outward, and the through hole 10 is formed near the outer periphery of the recess 5, the air 11 collected in the recess 5 is , the bottom surface 8 of the recess 5 as shown by the arrow
And it can escape smoothly to the outside of the flanges 2 and 3 through the through hole 10.

In the embodiment, a case has been described in which a flange portion is provided at both the upper and lower ends, but the present invention can also be applied to a reel in which a flange portion is provided at one end of the hub portion.

The present invention has the above-described structure, and when winding the magnetic tape, there is no air entrainment, the magnetic tape is wound in an orderly manner, and damage to the tape edges is eliminated.

[Brief explanation of the drawing]

The figures are all for explaining the magnetic tape reel according to the embodiment of the present invention, and Fig. 1 is a partially sectional front view of the tape reel, and Fig. 2 shows the upper flange of the tape reel. FIG. 3 is a plan view of the removed state, and an enlarged sectional view showing the state of air flow when the magnetic tape is wound around the tape reel. DESCRIPTION OF SYMBOLS 1...Hub part, 2...Lower flange part, 3...Upper flange part, 4...Magnetic tape, 5...Recessed part, 8
... Bottom surface, 9 ... Outer surface, 10 ... Through hole, 11 ...
air.

Claims (1)

[Scope of utility model registration request] In a magnetic tape reel, the magnetic tape reel has a hub portion around which a magnetic tape is wound, and a flange portion connected to at least one of the upper and lower ends of the hub portion and extending radially outward of the hub portion. A plurality of fan-shaped recesses expanding from the inner circumference toward the outer circumference are provided in the circumferential direction on the inner surface of the part, and the bottom surface of the recess is located on the outer circumference side from the center point between the inner circumference and the outer circumference of the recess. A magnetic tape reel characterized by having a through hole for air release penetrating through the outer surface of the flange.