JPS6230226Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a tape reel that is most suitable for application to tape reels stored in tape cassettes of VTRs, tape recorders, etc. Relates to a molded flange attached.

First of all, FIGS. 1 and 2 show a conventional example of a tape reel used in a tape cassette for a VTR, in which a lower flange 2 is integrally formed with a reel body 3 made of synthetic resin at the lower end of a hub 1. , hub 1
The upper flange 4 is formed separately from synthetic resin and is connected to the upper end of the upper flange 4. In order to connect the reel body 3 and the upper flange 4, first, a cylindrical part 6 is provided at the center of the upper end of the hub 1 on the reel body 3 side, and an annular gap 8 is provided around the outer periphery of the cylindrical part 6. , another cylindrical part 8 is provided, an annular step part 9 is provided inside the upper end of the cylindrical part 7 on the outer periphery, and six welding dowels 10 are provided on this annular step part 9. On the other hand, on the upper flange 4 side, a shallow cylindrical recess 11 is provided in the center thereof, a center hole 12 is provided in the center of the recess 11, and six dowel holes 13 are provided in the peripheral portion. Then, the upper flange 4 is fitted into the inner side of the cylindrical portion 8 on the outer periphery of the reel main body 3 through its recess 11 and placed on the annular step portion 9. At this time, the center hole 12 is fitted to the outer periphery of the central cylindrical portion 6, and the dowel holes 13 are inserted into the dowels 10, respectively.
Then, the upper end of the dowel 10 is welded to form the upper flange 4.
is configured to be integrally coupled to the reel body 3. Note that 14 is a semicircular tape winding part formed integrally with the reel body 3 on the outer periphery of the hub 1, and 15 is a semicircular tape clamp piece.

By the way, the minimum winding diameter of the tape in the above conventional example is
d ₁ is the diameter of the cylindrical surface 16 formed by the outer peripheral surfaces of the tape winding part 14 and the tape clamp piece 15, but the diameter of the cylindrical surface 16 is substantially the same as that of the hub 1 due to constraints on synthetic resin molding. The major factor for determining the outer diameter d ₂ of the hub 1 is the diameter d ₃ of the joint surface between the reel body 3 and the upper flange 4 mentioned _above . This is the maximum outer diameter of the recess 11 of the upper flange 4.

However, in the above conventional example, since the diameter d ₃ of the joint surface between the reel body 3 and the upper flange 4 is relatively large, the structure is such that the outer diameter d ₂ of the hub 1 cannot be made very small. The minimum winding diameter d _{1 of the tape, which is constrained by the outer diameter d 2 of} the hub 1, is relatively large.

On the other hand, in tape cassettes for VTRs and the like, there has recently been a trend to increase the length of the tape wound around the tape reel in order to increase the recording time of the tape. However, the maximum outer diameter of the tape reel has already reached its limit, and we are in a situation where it is not possible to increase the maximum tape winding diameter. The situation has reached a point where there is almost no other option than to reduce the diameter.

However, in the above conventional example, the structure makes it difficult to further reduce the minimum winding diameter d ₁ of the tape. It is almost impossible to increase the time.

The present invention was devised in view of the above-mentioned circumstances, and it makes it possible to greatly reduce the diameter of the joint surface between the reel body and the flange attached to it, thereby minimizing the tape winding. It is an object of the present invention to provide a tape reel whose diameter can be greatly reduced.

Note that the smaller the diameter of the above joint surface, the more
If the stability of the flange attachment to the reel body deteriorates, for example, if the flat part of the reel body to which the flange is tightly attached becomes bent due to "sink marks" during synthetic resin molding, etc., and is no longer flat. In this case, the flange cannot adhere to the flat part in a stable manner, and the flange becomes tilted, resulting in a non-parallel state between the upper and lower flanges. However, if such an unparallel state occurs, when the tape is wound, the edges of the tape may stretch or fold due to the flange, damaging the tape and making it impossible to provide a good image. This will cause fatal inconvenience.

Therefore, this invention solves the problem of the stability of attaching the flange to the reel body, and even though the diameter of the joint surface between the reel body and the flange is small, the flange can be attached stably to the reel body, and the upper and lower It is an object of the present invention to provide a tape reel that can achieve parallelism between a pair of flanges with high precision.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, in which an embodiment of a tape reel used in a tape cassette for a VTR is used.

First, in FIGS. 3 to 5, a reel main body 21 has a lower flange 20 integrally molded with synthetic resin at the lower end of the hub 19, and a reel main body 21 has a lower flange 20 molded separately from synthetic resin to be joined to the upper end of the hub 19. Upper flange 22
It is made up of.

In order to connect the reel body 21 and the upper flange 22, first, a small cylindrical part 24 is provided at the center of the upper end of the hub 19 on the reel body 21 side, and the end face of the cylindrical part 24 is connected to the outer diameter d of the hub 19. It is formed into a flat surface 25 with a diameter _d11 that is sufficiently smaller than ₁₀ .
At the center of the flat surface 25, there is provided a protrusion 26 consisting of a large diameter section 26a serving as a base and a narrow diameter section 26b that should protrude from the upper surface of the upper flange 22. For example, six welding dowels 27 are provided. On the other hand, on the upper flange 22 side, a shallow cylindrical recess 28 is provided in the center thereof, the lower surface of the recess 28 is formed into a flat surface 29 that is in close contact with the flat surface 25, and the center of the recess 28 is A center hole 30 is provided to fit into the thick warp portion 26a of the protrusion 26, and six dowel holes 31 into which the dowels 27 are fitted are provided around the recess 28.

4 or 5, the flat surface 25 of the reel body 21 or the flat surface 29 of the upper flange 22 and the large diameter portion 26 of the protrusion 26
An annular recess 33 or 34 is provided in a corner portion 43 or 44 that includes (that is, intersects with) a or the periphery of the center hole 30. Note that normally only one of these recesses 33 or 34 is required, but
Both may be provided together.

Then, the upper flange 22 is connected to the thick longitudinal portion 2 of the protrusion 26 of the reel main body 21 through its center hole 30.
6a, and insert the dowel 27 into the dowel hole 31.
The reel main body 21 and the upper flange 22 are brought into close contact with each other by the flat surfaces 25 and 29. The upper flange 22 is integrally connected to the reel body 21 by bringing the upper end of the dowel 27 into close contact. Furthermore, 36
3 is a semi-circular tape winding part formed integrally with the reel body 21 on the outer periphery of the hub R, and 37 is a semi-circular tape clamp piece.

By the way, the minimum winding diameter of the tape in this example is
d ₁₂ is a cylindrical surface 38 formed by the outer peripheral surface of the tape winding part 36 and the tape clamp piece 37 as in the conventional case.
However, the minimum winding diameter d ₁₂ of the tape is greatly reduced compared to d ₁ of the conventional example shown in FIG.

That is, the diameter d ₁₁ of the joint surface between the reel body 21 and the upper flange 22 is here the diameter of the flat surface 25, but this diameter d ₁₁ is different from that of the conventional example shown in FIG. 2, d _{3 .} Compared to , it has been reduced to a large width.
As a result, hub 1 determined by this diameter d ₁₁
The outer diameter d ₁₀ of the tape ₉ is greatly reduced compared to _{d 2} of the conventional example shown in FIG. succeeded in reducing it.

Note that since the diameter d ₁₁ of the joint surface is greatly reduced, the stability of attachment of the upper flange 22 to the reel body 21 becomes worse. That is, as shown in FIG. 6, for example, the flat surface 25 of the reel body 21, to which the upper flange 22 is closely attached, is bent due to "sink marks" during synthetic resin molding and is no longer flat. In this case, the flat surface 29 of the upper flange 22
The upper flange 22 will not be able to adhere to the flat surface 25 in a stable manner, and the upper flange 22 will be tilted and become non-parallel with the lower flange 20.
This is because, due to the above-mentioned bending of the flat surface 25, the flat surface 29 of the upper flange 22 is in line contact with the flat surface 25 within a very small diameter _d13 only in the vicinity of the periphery of the protrusion 26. An annular gap 4 is formed between the flat surface 29 and the peripheral portion of the flat surface 25.
This is caused by the fact that the upper flange 22 is supported in a pivoting manner.

However, in this embodiment, as shown in FIG. 4 or 5, the flat surface 25 or 29 is provided with an annular recess 33 or 34. Therefore, even if the flat surface 25 of the reel main body 21 is bent due to sink marks or the like during synthetic resin molding, the flat surface 29 of the upper flange 22 can be moved away from the vicinity of the protrusion 26. , to make the diameter d ₁₄ of the mutually contacting portion of both flat surfaces 25 and 29 sufficiently larger than that d ₁₃ of FIG. Can be done.
As a result, the upper flange 22 can be mounted in contact with the reel body 21 in a very stable manner, and the upper flange 22 does not tilt at all.
The parallelism between the lower flange 20 and the lower flange 20 can be achieved with high precision.

Moreover, in this embodiment, as shown in FIG. 4 or 5, the annular recess 33 or 34 is
It is provided at a corner portion 43 or 44 that includes (that is, intersects) the large diameter portion 26a of No. 6 or the periphery of the center hole 30 and the flat surface 25 or 29. Therefore, due to the influence of "sink marks" etc. during synthetic resin molding, the large diameter portion 26 of the protrusion 26
Even if a rounded surface is generated in the corner portion 43 including the periphery of a and the flat surface 25, in FIG. 29, and in FIG. 5, its rounded surface is released by the annular recess 34 provided in the corner portion 44 of the upper flange 22, so that both flat surfaces 25 and 29 are securely brought into close contact. It turns out. Therefore, even if an R surface occurs during molding, the upper flange 22 and the lower flange 2
In addition to being able to achieve high precision parallelism between the
It is also possible to prevent the upper flange 22 and the lower flange 20 from floating up from 1, and the interval between the upper flange 22 and the lower flange 20 can be set with high precision.

As described in the embodiments above, according to the present invention, the minimum winding diameter of the tape can be greatly reduced compared to the conventional method, and the length of the tape to be wound can be increased, thereby increasing the recording time. I can do it. At the same time, the attachment of the flange to the reel body is highly stable, and the flange can be attached to the reel body with good stability, so that the parallelism and spacing between the pair of upper and lower flanges can be achieved with high precision. Therefore, when winding the tape, the flange does not cause any damage to the tape, such as elongation or folding of the edges of the tape, which has the advantage of increasing the life of the tape and providing good images. be.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing a conventional example, and Fig. 2 is a plan view showing a conventional example.
It is a figure-line sectional view. 3 to 5 show an embodiment of the present invention, in which FIG. 3 is a plan view, FIG. 4 is a sectional view taken along the line of FIG. 3, and FIG. 5 is a modified example. 4 is a sectional view similar to FIG. 4, and FIG. 6 is a sectional view shown as a reference view for explaining the inclination of the upper flange. In addition, in the symbols used in the drawings, 19
... Hub, 20 ... Lower flange, 21 ... Reel body, 22 ... Upper flange, 25 ... Flat surface, 2
6...Protrusion, 29...Flat surface, 26a...Protrusion 2
Large diameter part of 6, 26b...Small diameter part of protrusion 26, 43
... Corner part, 44 ... Corner part, 30 ...
A central hole, 33...an annular recess, and 34...an annular recess.

Claims (1)

[Scope of utility model registration request] A flat surface that is sufficiently smaller than the outer diameter of the hub is provided at the center of the end of the hub of the reel body, and a large diameter portion that serves as a base and a small diameter portion that should protrude from the top surface of the upper flange are provided at the center of the flat surface. A flat surface is provided at the center of the upper flange attached to the reel body, a center hole is provided at the center of the flat surface, and the upper flange is connected to the reel body by the center hole. The upper flange is fitted into the large diameter portion of the protrusion of the reel body and the flat surfaces are brought into close contact with each other, and the upper flange is integrally coupled to the reel body;
and a tape reel comprising an annular recess provided in a corner portion including a large diameter portion of the protrusion or a periphery of the center hole and a flat surface of the reel body or a flat surface of the upper flange.