JPH10275445A - Magnetic tape cassette reel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the magnetic tape cassette reel capable of stabilizing recording characteristics and reproducing characteristics by a lower flange capable of making resin-flows uniform with less deformation. SOLUTION: This magnetic tape cassette reel is equipped with the lower flange 11 in a circular shape, a reel hub 12 in a cylindrical shape projected in the middle part of the lower flange to be wound with a magnetic tape, clamp recessed parts 13 provided on the outer circumferential surface of the reel hub 12 for the purpose of fixing the magnetic tape, welded bosses 15 provided on the upper end surface of the reel hub 12 and an upper flange in a circular shape welded on the welded bosses 15. Then, the outer circumferential surface of the reel hub 12 is provided with three clamp recessed parts 13 at the same intervals in the circumferential direction, and a resin is injected from resin injecting gates 19 provided on the upper end surface of the reel hub and in their positions at equal distance from the individual clamp recessed parts 13, thus molding the magnetic tape cassette reel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reel for a magnetic tape cassette on which a magnetic tape is wound, and more particularly to a tape reel suitable for use in a magnetic tape cassette such as a video tape cassette.

[0002]

2. Description of the Related Art Conventionally, various types of reels for magnetic tape cassettes, for example, capable of winding or unwinding a magnetic tape, have been used. The magnetic tape cassette reel has a form as shown in FIG. 4, for example.

In the conventional magnetic tape cassette reel 5 shown in FIG. 4, a reel hub 52 as a core portion for winding a magnetic tape T (a part is shown by imaginary lines) on a circular lower flange 51 is projected. Has been established. This reel hub 52
Is provided with a clamp recess 53 for fixing an end of the magnetic tape T. When fixing the magnetic tape T to the clamp recess 53, the magnetic tape T
The magnetic tape T is fixed by making the end of the magnetic tape T correspond to the clamp concave portion 53 and fitting the clamp member 54 thereon.

On the upper end surface of the reel hub 52, a plurality of
For example, three welding bosses 55 are provided. And
A circular upper flange 56 is placed on the upper end surface of the reel hub 52, and a welding boss 55 is inserted into a boss hole 57 of the upper flange 56.
Is fitted and welded. When the end of the magnetic tape T is not properly mounted, the upper flange 56 is provided with an extraction hole 58 that is slightly larger than the clamp member 54, if necessary, to extract the clamp member 54 from the clamp recess 53. .

[0005]

As described above, in the conventional magnetic tape cassette reel 5, the clamp recess 53 is indispensable. Therefore, in the molding die at the time of reel molding, for example, the resin injected from the resin injection gate provided at the center of the reel hub 52 has the core disposed in the die to form the clamp recess 53. Is done. Therefore, when the resin is extruded into the injection space forming the lower flange and spreads, the flow of the resin becomes uneven (the flow of the resin is obstructed by the core). Therefore, the degree of filling of the lower flange 51 with the resin is different. For this reason, the lower flange 51 is often deformed, and as a result of this deformed portion being concentrated in one place, the deformation tends to be large. Thus, when the deformation at the lower flange 51 is large,
When the magnetic tape cassette reel 5 rotates (when the tape is running), there is a problem that the runout of the flange surface increases. This surface run-out causes a decrease in the tape running property, and is a major factor that deteriorates the recording characteristics and the reproduction characteristics of the magnetic tape.

Further, in the conventional magnetic tape cassette reel 5, when the upper flange 56 and the reel hub 52 are assembled, the clamp member 54 can be removed from the extraction hole 58 after the assembly so that the clamp member 54 can be taken out from the extraction hole 58. The formed extraction hole 58 and the crank recess 53 must be aligned. This positioning operation was a major factor in reducing the assemblability of the magnetic tape cassette reel 5.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and a first object of the present invention is to provide a magnetic tape cassette capable of preventing a decrease in recording and reproducing characteristics of a magnetic tape caused by an uneven flow of resin. To provide a reel. A second object is a magnetic tape cassette reel that can easily determine an assembling position without having to select an attaching position when the upper flange is attached to a reel hub, and can improve assemblability. Is to provide.

[0008]

SUMMARY OF THE INVENTION The first object of the present invention is to provide a lower reel, a cylindrical reel hub projecting from the center of the lower flange and winding a magnetic tape, and an upper end face of the reel hub. A magnetic tape cassette reel having an upper flange and a clamp concave portion provided on the outer peripheral surface of the reel hub and fitted with a clamp member for fixing the magnetic tape, wherein at least two reels are provided on the outer peripheral surface of the reel hub. The two clamp recesses are provided at equal intervals in the circumferential direction, and are injected from a resin injection gate provided at the upper end surface of the reel hub and at a position equidistant from the at least two clamp recesses. This is achieved by a magnetic tape cassette reel characterized in that the reel is made of a molded resin.

As a preferred embodiment of the present invention, the same number of the gates as the clamp recesses are provided and molded. According to the above configuration, a plurality of clamp concave portions are provided at equal intervals in the circumferential direction on the outer peripheral surface of the reel hub, so that the core for forming the clamp concave portion has a lower flange planar shape (circular shape) in the molding die. Can be arranged at symmetrical positions with respect to the center line. Therefore, the gate for resin injection can be arranged at a position equidistant from the core, whereby a contrasting flow can be created when the resin spreads into the injection space constituting the lower flange. As a result, it is possible to prevent the resin filling from being biased in the plane of the lower flange, and to reduce the amount of deformation of the lower flange.

A second object of the present invention is to provide a reel hub having a lower flange and an upper flange protruding from a central portion thereof and being attached to an upper end surface of a reel hub for winding a magnetic tape. The upper flange is provided with at least two extraction holes having a clamp recess for fitting a clamp member to fix the tape, and having a shape capable of extracting the clamp member fitted to the clamp portion. In the magnetic tape cassette reel, the reel hub and the upper flange are provided with at least two welding bosses and boss holes that are welded and engaged with each other at regular intervals in the circumferential direction of the reel hub and the upper flange. The extraction hole provided in the upper flange has a position with respect to the boss hole, the boss of the clamp recess provided in the reel hub. It is achieved by a reel for a magnetic tape cassette, characterized in that it is formed to match in a plan view with respect to the position of. According to the above configuration, the position of the extraction hole provided in the upper flange with respect to the boss hole is formed so as to match the position of the clamp recess provided in the reel hub with respect to the boss in a plan view. Therefore, any of the extraction holes is aligned with the clamp recess regardless of the welding position of the upper flange.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a magnetic tape cassette reel according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing a magnetic tape cassette reel according to the first invention. In the magnetic tape cassette reel 1 shown in FIG. 1, a cylindrical reel hub 12 for winding a magnetic tape (not shown) is projected from a circular lower flange 11 as in the conventional case. Further, a plurality of, for example, three welding bosses 15 are provided on the upper end surface of the reel hub 12.
Is provided. Then, a circular upper flange 16 is placed on the upper end surface of the reel hub 12, and the upper flange 16
The welding boss 15 is fitted into the three boss holes 17 and welded.

However, unlike the conventional one, the magnetic tape cassette reel 1 has a plurality of, in this embodiment, two clamp recesses 13 capable of fixing the end of a magnetic tape (not shown) to the outer peripheral surface of a reel hub 12. , 13 are provided at equal intervals. These clamp recesses 13 and 13 are formed in the shape of a concave groove that extends deeper. The clamp members 14 fitted into the respective clamp recesses 13 are stepped at both ends. After the clamp members 14 are fitted so as to be pushed into the clamp recesses 13, they are removed in the radial direction of the reel hub 12. You can't do that, but you can pull it out.

The magnetic tape can be fixed by fitting the end of the magnetic tape to any one of the clamp concave portions 13 and 13 and fitting the clamp member 14 thereon. The other clamp recess 1
3, the clamp member 14 is fitted. Further, when the end of the magnetic tape is not properly attached, it is necessary to take out the clamp member 14 from the clamp recess 13. Therefore, the upper flange 16 is provided with an extraction hole 18 slightly larger than the clamp member 14.

The lower flange 11 is formed by appropriately injecting a resin into an injection space of a molding die. Less than,
The injection of the resin during the molding will be described with reference to FIG. FIG. 2 is a view of the lower flange 11 before the upper flange 16 is attached, as viewed from above. In this figure, the injection gate 19 will be described for convenience.

As shown in FIG. 2, a plurality of resin members are provided between the positions where the clamp recesses 13 and 13 are formed on the upper end surface side of the reel hub 12 (actually, a core or the like which fills the injection space is provided). Gates 19 for injection are provided, and molding is performed by injecting a resin from the gates 19 for resin injection into a mold (not shown). The gates 19, 19 are provided with clamp recesses 13, 13,
It is preferable to set the same number as
13 is preferably provided at a position that is equidistant from 13.

As described above, in the magnetic tape cassette reel 1 according to the present embodiment, the plurality of clamp recesses 13 are provided on the lower flange 11 at equal intervals, and are located at equal distances between the clamp recesses 13. It is molded with a resin injected from a plurality of gates 19 provided so as to be in contact with each other. Therefore, the gates 19, 19 and the lower flange 11
All parts including the clamp recesses 13 and 13 have a configuration substantially similar to point symmetry.

Accordingly, when the resin injected from the gates 19 and 19 spreads into the injection space forming the lower flange 11, the flow is balanced with the plane shape of the lower flange 11. Flows uniformly throughout.
Therefore, variation in resin filling can be suppressed,
Deformation can be kept small. For this reason, it is possible to prevent surface run-out during rotation of the magnetic tape cassette reel 1, thereby stabilizing the recording characteristics and the reproduction characteristics of the magnetic tape. In the magnetic tape cassette reel 1 described above, the clamp recess 1
Although the case where two are provided has been described, three or more clamp recesses 13 may be provided. Also in this case, it is preferable that the clamp concave portions 13 are arranged at equal intervals.

FIG. 3 is a perspective view showing a magnetic tape cassette reel 2 according to the second invention. Note that the first
The same components as those of the magnetic tape cassette reel 1 according to the present invention are denoted by the same reference numerals, and detailed description thereof will be omitted.
The magnetic tape cassette reel 2 shown in FIG. 3 includes a clamp member 1 fitted in a clamp recess 13 of a lower flange 11.
In order to take out 4, the upper flange 16 is provided with the same number of extraction holes 21 as the welding bosses 15.

In this embodiment, the reel hub 12 has three welding bosses 15 and three boss holes 17 which are welded to each other.
And the upper flange 16 are provided at equal intervals in the circumferential direction, and the extraction hole 21 provided in the upper flange 16 is provided at a position with respect to the boss hole 17 of the clamp recess 13 provided in the reel hub 12. Three are provided at equal intervals in the circumferential direction so as to coincide with the position with respect to the boss hole 17 in plan view.

As described above, in the magnetic tape cassette reel 2 of the second invention, the position of the extraction hole 21 provided in the upper flange 16 with respect to the boss hole 17 is the same as that of the clamp recess 13 provided in the reel hub 12. When the upper flange 16 is attached to the reel hub 12, an arbitrary welding boss 15 is inserted into each boss hole 17 of the upper flange 16. By simply fitting the, the one of the extraction holes 21 is aligned with the clamp member 14. Therefore, when the upper flange 16 is attached to the lower flange 11, it is only necessary to determine the positional relationship with the welding boss 15, so that automatic assembly is also facilitated. In the above embodiment, the welding boss 15 is used.
Has been described, but the number of the welding bosses 15 can be two or four or more.
The same number of extraction holes 21 as 5 may be provided.

[0021]

As described above, in the magnetic tape cassette reel according to the first aspect of the present invention, a plurality of clamp recesses are provided at equal intervals on the outer peripheral surface of the reel hub, so that the clamp recesses are formed in the molding die. Core can be arranged symmetrically with respect to the center line of the lower flange planar shape, and the gate for resin injection can be arranged at a position equidistant from the core. Therefore, it is possible to create a contrasting flow when the resin spreads into the injection space constituting the lower flange, to prevent uneven filling of the resin in the plane of the lower flange, and to reduce the amount of deformation of the lower flange. Can be. Therefore, according to the first aspect, it is possible to prevent surface run-out during rotation of the magnetic tape cassette reel, thereby stabilizing the recording characteristics and the reproduction characteristics of the magnetic tape.

Further, in the magnetic tape cassette reel according to the second invention, the position of the extraction hole provided in the upper flange with respect to the boss hole is set with respect to the position of the clamp recess provided in the reel hub with respect to the boss. Since it is formed so as to match in plan view, any of the extraction holes is aligned with the clamp recess regardless of the welding position of the upper flange. Therefore, according to the second invention, when the upper flange is attached to the reel hub, only the positional relationship with the welding boss needs to be determined, so that the assembling of the upper flange and the reel hub is facilitated, and automatic assembly is also facilitated. Thus, it is possible to provide a magnetic tape cassette reel having excellent assemblability.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a magnetic tape cassette reel according to a first invention.

FIG. 2 is a plan view for explaining a method of forming a lower flange of the magnetic tape cassette reel according to the first invention.

FIG. 3 is a perspective view showing a reel for a magnetic tape cassette according to a second invention.

FIG. 4 is a perspective view showing a conventional reel for a magnetic tape cassette.

[Explanation of symbols]

 1, 2 Magnetic tape cassette reel 11 Lower flange 12 Reel hub 13 Clamp recess 14 Clamp member 15 Welding boss 16 Upper flange 19 Gate for resin injection 21 Extraction hole

Claims (3)

[Claims] A lower flange, a cylindrical reel hub protruding from a central portion of the lower flange and winding a magnetic tape, and an upper flange assembled to an upper end surface of the reel hub;
A magnetic tape cassette reel provided on an outer peripheral surface of the reel hub and provided with a clamp concave portion for fitting a clamp member for fixing the magnetic tape, wherein at least two of the clamp concave portions are formed on an outer peripheral surface of the reel hub in a circumferential direction. Are formed at a regular interval, and are formed of resin injected from a resin injection gate provided at a position on the upper end surface of the reel hub at an equal distance from the at least two clamp concave portions. A reel for a magnetic tape cassette. 2. The magnetic tape cassette reel according to claim 1, wherein the same number of gates as the clamp recesses are provided and molded. 3. A clamp for fixing the tape to the outer peripheral surface of the reel hub, comprising a lower flange and an upper flange protruding from a central portion thereof and being attached to an upper end surface of a reel hub for winding a magnetic tape. A magnetic tape cassette reel having a clamp recess for fitting a member and having at least two ejection holes formed in the upper flange and having a shape capable of extracting a clamp member fitted to the clamp portion; The reel hub and the upper flange are provided with at least two welding bosses and boss holes that are welded and engaged with each other at equal intervals in the circumferential direction of the reel hub and the upper flange. The extraction hole is positioned such that the position with respect to the boss hole is planar with respect to the position of the clamp recess provided on the reel hub with respect to the boss. Reel for a magnetic tape cassette, characterized in that it is formed to match Te.