JPH01294285A - Production of reel hub for magnetic tape cartridge - Google Patents

Abstract

PURPOSE:To uniformly chuck a reel hub to smoothly and stably run a tape by cambering a metallic disk with its shaft hole as the center and performing insert molding. CONSTITUTION:A metallic disk 20 which is preliminarily cambered with a shaft hole 22 as the center is used to perform insert molding, and this metallic disk 20 is so arranged that the contractive force due to solidification of plastics at the time of insert molding in a mold is applied in the direction where the cambered disk 20 is straightened. Consequently, when the degree of camber is determined in accordance with the magnitude of the contractive force, the flatness of the metallic disk 20 constituting the bottom of a reel hub 26 is improved. Thus, the reel hub 26 is uniformly chucked, and the magnetic tape is smoothly and stably fed out and rewound.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic tape cartridge in which a magnetic tape is wound around a single reel hub and rotatably housed in a case, and in particular to a method for manufacturing the single reel hub by insert molding. .

2. Description of the Related Art Conventionally, magnetic tape cartridges used in auxiliary storage devices of computers, etc. have a magnetic tape wound around a single reel hub and rotatably housed in a case. Such a reel hub is manufactured by insert molding, in which a metal disk having a shaft hole in the center is inserted into plastic, and the bottom surface of the metal disk is formed of the metal disk. Even if the reel hub is housed in the case, this metal disk is always exposed to the outside through the drive shaft window in the center of the lower case. Therefore, when a magnetic tape cartridge is installed in a magnetic recording/reproducing device, the metal disk rides on the drive stand of the device, is attracted to a magnet, and is chucked there.

At that time, the drive shaft on the table is inserted into the shaft hole of the metal disk,
Use the head to push up the reel brake member such as the brake button and remove the brake from the reel hub. Therefore, the stored magnetic tape can be pulled out from the reel hub, loaded or unloaded, and data can be written or read thereon.

Problems to be Solved by the Invention However, such a reel hub has a metal disk 1 with good flatness having a shaft hole 10 in the center as shown in FIG.
Even if 2 is used, during insert molding, the plastic will be pulled upward due to shrinkage due to assimilation, and a very large force will be applied in the direction of the arrow. Therefore, in the molded product taken out from the mold, the metal disk 12 has a shaft hole 1 on the plastic side (upper side) forming the main body 14 of the reel hub, as shown in FIG.
It will warp around 0, making it impossible to maintain its flatness. By the way, 16 in the figure is the hub,
18 is the lower flange. As a result, the reel hub is not chucked uniformly, and the magnetic tape may not be smoothly fed or wound, causing trouble.

The present invention has been made in view of these conventional problems, and an object of the present invention is to provide a method of manufacturing a reel hub for a magnetic tape cartridge whose bottom surface can be constructed of a metal disk with good flatness by insert molding. shall be.

Means for Solving the Problems Means for achieving the above object will be explained below with reference to FIGS. 1, 2, and 5, which correspond to embodiments.

This method of manufacturing a reel hub for a magnetic tape cartridge involves winding a magnetic tape around a single reel hub 26 having a bottom surface composed of a metal disk 20 having a shaft hole 22 in the center by insert molding, and rotatably storing the magnetic tape in a case 36. In this method of manufacturing a reel hub of a tape cartridge, a metal disk 20 is curved around its shaft hole 22 and insert molding is performed.

Effects With the above structure, insert molding is performed using the metal disk 20 whose surface has been warped around the shaft hole 22 in advance, so that the metal disk 20 is placed in the mold by assimilation of the plastic during insert molding. If the arrangement is made so that the contraction force is applied in the direction to correct the surface warpage, the flatness of the metal disk 20 that forms the bottom surface of the reel hub 26 can be adjusted by determining the degree of surface warpage according to the magnitude of the contraction force. It can be made good. Therefore, chucking to the reel hub 26 is performed uniformly, and the feeding and winding operations of the magnetic tape become smooth and stable.

Example Hereinafter, the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a metal disk used in a reel hub for a magnetic tape cartridge to which the present invention is applied, and FIG. 2 is a longitudinal sectional view of the same reel hub. In the figure, 20 has a shaft hole 22 in the center.
It is a metal disk having a cylindrical shape, and is curved around its shaft hole 22. The degree of this surface warpage corresponds to the shrinkage force caused by solidification of the plastic during insert molding.

That is, when the metal disk 20 is placed in the mold, the shrinkage force due to the solidification of the plastic during insert molding corrects the warping of the surface of the metal forming the bottom surface of the molded product! The flatness of 20 is determined to be good.

When this metal disk 20 is placed at a predetermined location in a mold and insert molding is performed, the plastic side forming the main body 24 of the reel hub is pulled by the shrinkage force due to its assimilation, and the surface warpage that has been applied in advance is corrected.

Therefore, the bottom surface of the reel hub 26 taken out from the mold is composed of a metal disk 20 with good flatness.

Incidentally, 28 in the figure is a hub, and 30 is a lower flange. The external appearance of the reel hub 26 is shown in FIG. 3 (perspective view) and FIG. 4 (bottom view). In the figure, 32 is a large number of pawls that engage with the brake button, and 34 is three holes that connect the metal disk 20 to the reel hub body 24.

By combining the upper flange with such a reel hub 26, winding a magnetic tape around it, and storing it in a case along with a brake button and a spring that biases it, a magnetic tape cartridge as shown in FIG. 5 is obtained. It will be done. In the figure, 36 is a cartridge case that combines an upper case 38 and a lower case 40, 42 is a leader block facing an opening in one corner of the cartridge case, and 44 is a reader block for preventing erroneous recording facing an opening in the peripheral side wall of the upper case 38. is the selector of

Note that the free end of the magnetic tape is fixed to the leader block by a clamp.

In use, when the magnetic tape cartridge is installed in a magnetic recording/reproducing device, the reel hub 26 rests on the drive stand of the device. At that time, the metal disk 2 forming the bottom surface of the reel hub 26
It is attracted to the magnet on the platform of 0 and chucked there. At the same time, the drive shaft on the table is inserted into the shaft hole 22 in the center of the metal disk 20, and its head pushes up the reel brake members such as the brake button 46 and spring 48 as shown in FIG. The brake applied to the reel hub 26 can be removed. In addition, 5 in the figure
0 is an upper 7 lunge, 52 is a clamp. Therefore, when the reel hub 26 is driven, the metal disk 20 forming the bottom surface has good flatness and chucking is performed uniformly, so the reel hub 26 smoothly feeds out the magnetic tape (not shown) or The tape can be wound up and run by loading or unloading, and data can be written or read on the tape.

According to the present invention, which has been described in detail, the flatness of the metal disk that forms the bottom surface of the reel hub is improved, and chucking is performed uniformly, resulting in smooth and stable tape running and accurate data writing. It can be read and read.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a metal disk used in a reel hub for a magnetic tape cartridge to which the present invention is applied, and FIG. 2 is a longitudinal sectional view of the same reel hub. FIG. 3 is a perspective view showing the appearance of the reel hub, and FIG. 4 is a bottom view thereof. FIG. 5 is a perspective view showing the external appearance of the magnetic tape cartridge, and FIG. 6 is an exploded perspective view thereof. FIG. 7 is a longitudinal sectional view of a metal disk used in a conventional reel hub for a magnetic tape cartridge, and FIG. 8 is a longitudinal sectional view of the same reel hub. 20...Metal disk 22...Center shaft hole 24...
Reel hub body 26...Reel hub 28...Hub 30...Lower flange 36...Cartridge case 38.40...Upper and lower case Patent applicant TDC Co., Ltd. Agent Patent attorney Dai Yanagisawa Construction Fig. 1 20 Metal disc 22 Center shaft hole Fig. 2 Slot 26 Reel hub 28 Hub 60 Lower flange Fig. 3 Fig. 7 Fig. 8

Claims (1)

[Claims] In a reel hub manufacturing method for a magnetic tape cartridge, in which a magnetic tape is wound around a single reel hub having a bottom surface composed of a metal disk with an axial hole in the center by insert molding and rotatably housed in a case, the metal disk is A method of manufacturing a reel hub for a magnetic tape cartridge characterized by performing insert molding by warping the surface around the shaft hole.