JPH04228162A - Tape reel - Google Patents

Abstract

PURPOSE:To prevent the strain of the out-of-roundness of a tape winding surface from occurring by utilizing the outer peripheral surface of the inner cylindrical part of a hub and positioning the radial direction and the circumferential direction of an upper flange with respect to the hub. CONSTITUTION:The upper flange 7 made of synthetic resin is placed on the upper end face 4a of the inner cylindrical part 4 of the hub 1 integrally molded with a lower flange 2 with the synthetic resin by the central circular swelling part 13 of the flange 7. At such a time, the rib 17 integrally molded with the flange 7 is fitted in the outer peripheral surface 4b of the cylindrical part 4 without looseness, and a pair of locking parts 18 projecting to the inner side of the rib 17 is locked on both end faces 16a of a recessed part 16 formed on the outer peripheral surface 4b of the cylindrical part 4 without looseness. By thus doing, the strain of the circularity of the tape winding surface 5 is prevented from occurring.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape reel that is used, for example, in a tape cassette for a video tape recorder, and is made of synthetic resin and has upper and lower flanges at both upper and lower ends of a hub.

0002

2. Description of the Related Art A conventional example of a tape reel used in a tape cassette for a video tape recorder will be explained with reference to FIGS. 5 and 6.

[0003] In this conventional example, a hub 1 and a lower flange 2 provided at its lower end are integrally molded from synthetic resin.
The hub 1 is provided with an inner cylindrical part 4 whose inside is formed into the reel shaft insertion hole 3 and an outer cylindrical part 6 whose outer peripheral surface is formed with the tape winding surface 5, and an upper flange 7 molded from synthetic resin.
is welded to the upper end surface 4a of the inner cylindrical portion 4 of the hub 1. Note that 8 is a large number of reel claws provided on the inner peripheral surface of the reel shaft insertion hole 3.

By the way, in this type of tape reel, after the upper flange 7 is welded to the hub 1, the clamp piece 9 is attached.
from the driving opening 10 provided in the upper flange 7 to the hub 1
The magnetic tape 12 is driven into the clamp piece locking groove 11 provided in the outer cylindrical part 6 from the direction of arrow a in FIG. . Therefore, when welding the upper flange 7 to the hub 1, it is necessary to accurately position the driving opening 10 directly above the clamp piece locking groove 11. Also, it goes without saying that the upper flange 7 must be properly welded to the hub 1 so that they are coaxial.

Therefore, in this type of tape reel, the upper flange 7 must be welded to the hub 1 while being correctly positioned in both the radial direction and the circumferential direction.

[0006]

[Problems to be Solved by the Invention] The tape reel shown in the earlier application example (Utility Application No. 129482/1982) filed earlier by the applicant of the present invention has a ceiling plate that connects the upper end of the inner cylindrical part of the hub. Since the structure is closed, a plurality of dowels are integrally formed on the ceiling plate, and by engaging the plurality of dowel holes provided in the upper flange with the dowels, the upper flange is connected to the hub. Both radial and circumferential positioning is possible.

However, in the conventional example shown in FIGS. 5 and 6, the upper end of the inner cylindrical portion 4 of the hub 1 is open.
The upper end surface 4a of the inner cylindrical portion 4 has a very small welding area.
It is a structure in which the upper flange 7 must be welded to the
It is not possible to integrally mold and provide a plurality of dowels as shown in the above-mentioned example of the prior application on the upper end surface 4a, which has a very small welding area. In addition, in FIG. 6, the outer circumferential surface 13a of the downwardly circular bulging portion 13 provided at the center of the lower surface of the upper flange 7 is press-fitted into the inner circumferential surface 6a of the outer cylindrical portion 6 without wobbling, and the hub 1 A method of positioning the upper flange 7 in the radial direction with respect to Wrinkles occur in the magnetic tape 12 wound on the winding surface 5. Therefore, the outer peripheral surface 13
A gap 14 must be provided between the outer cylindrical portion 6 and the inner circumferential surface 6a, and the upper flange 7 cannot be positioned by the outer cylindrical portion 6.

The present invention enables positioning of the upper flange relative to the hub in both the radial and circumferential directions using the outer circumferential surface of the inner cylindrical portion of the hub.

[0009]

[Means for Solving the Problems] The present invention provides a tape reel as shown in FIGS. 5 and 6, in which a concave portion is provided on the outer peripheral surface of the inner cylindrical portion of the hub, and a planar shape is provided on the lower surface of the upper flange. A C-shaped rib is integrally molded, and the open end of this rib is provided with a pair of locking parts that protrude inwardly, and the upper flange is connected to the upper part of the inner cylindrical part of the hub. When placed on the end face, the ribs are fitted into the outer peripheral surface of the inner cylindrical portion, and the pair of locking portions are locked in the recesses.

0010

[Operation] The present invention utilizes the outer peripheral surface of the inner cylindrical portion of the hub to accurately and reliably position the upper flange relative to the hub in both the radial and circumferential directions. Distortion does not occur in the roundness of the tape winding surface, which is the outer peripheral surface of the outer cylindrical portion.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a tape reel for use in a tape cassette for a video tape recorder according to the present invention will be described below with reference to FIGS. 1 to 4. Note that the same reference numerals are given to the same structural parts as those of the conventional example explained in FIGS. 5 and 6, and the explanation thereof will be omitted.

First, the present invention provides a clamp piece locking groove at a position opposite to the clamp piece locking groove 11 on the outer circumferential surface 4b of the inner cylindrical portion 4 of the hub 1 molded from synthetic resin as described above. A recess 16 having a wider width in the circumferential direction than 11 is provided. On the other hand, as mentioned above, a rib 17 having a C-shaped planar shape is integrally molded along the periphery of the lower surface of the central circular bulge 13 of the upper flange 7 molded from synthetic resin. There is. Furthermore, a pair of locking portions 18 are provided at the open ends of the ribs 17, and project into the inside of the ribs 17, and these pair of locking portions 18 are used for driving the clamp piece, as shown by chain lines in FIG. They are located at equal intervals on both sides of the opening 10 in the circumferential direction.

According to the present invention, when the upper flange 7 is placed on the upper end surface 4a of the inner cylindrical portion 4 of the hub 1 by the circular bulge 13 at the center as shown in FIGS. As shown in FIG.
As shown in the figure, a pair of locking portions 18 are configured to lock onto both end surfaces 16a of the recess 16 in the circumferential direction without wobbling. As a result, the upper flange 7 is correctly positioned with respect to the hub 1 in both the radial direction and the circumferential direction, the upper flange 7 is accurately positioned on the same axis with the hub 1, and the clamp piece is driven. The opening 10 for this purpose is precisely positioned directly above the clamp piece locking groove 11.

As described above, the present invention utilizes the outer circumferential surface 4b of the inner cylindrical portion 4 of the hub 1 to position the upper flange 7 relative to the hub 1 in both the radial and circumferential directions. , as shown in FIG.
As in the conventional example, a gap 14 can be provided between the tape winding surface 5 and the tape winding surface 5, which is the outer peripheral surface thereof, so that no distortion occurs in the roundness of the tape winding surface 5.

[0015] In addition, with the positioning as described above,
As shown in FIG. 1, the welding horn 20 is pressed against multiple locations around the circular bulge 13 of the upper flange 7, and the upper flange 7 is attached to the upper end surface 4a of the inner cylindrical portion 4 of the hub 1 as in the conventional example. Similarly, welding (ultrasonic welding) will be performed.

In the embodiment of the present invention, FIGS. 3 and 4
As shown in FIG. 2, a plurality of reinforcing ribs 21 are integrally molded to connect the outer circumferential surface 4b of the inner cylindrical portion 4 of the hub 1 and the inner circumferential surface 6a of the outer cylindrical portion 6. The rib 17 of the upper flange 7 is provided with a plurality of slits 22 that are fitted into the plurality of reinforcing ribs 21, and the engagement of these reinforcing ribs 21 and slits 22 causes the upper flange 7 to move against the hub 1. The circumferential positioning force of is further increased.

In the embodiment of the present invention, FIGS. 1 and 3
As shown in FIG. 2, an annular step 23 is provided on the inner periphery of the upper end surface 4a of the inner cylindrical portion 4 of the hub 1, and the outer periphery 24a of a metal plate 24 made of a stainless steel disc or the like is horizontally inserted into the annular step 23. In this state, the upper flange 7 is welded to the upper end surface 4a of the inner cylindrical portion 4 as described above, and the circular bulge 13 of the upper flange 7 presses the metal plate 24 from above to form the hub. It is fixed at 1. Further, a circular opening 25 is provided in the center of the circular bulging portion 13.

When the tape reel constructed as in this embodiment is assembled into a tape cassette for a video tape recorder, the upper half 32 of the tape cassette 31 is attached as shown by the chain line in FIG. A hemispherical convex portion 34 a integrally provided on the central lower surface of the synthetic resin reel holder 34 , which is pressed downward by a compression coil spring 33 , presses the metal plate 24 inside the central opening 25 of the upper flange 7 . It comes to be pressed against the top center of the. Note that the lower flange 2 is pressed against the lower half 3 by the pressure of the reel presser 34.
5, and the lower half 35 is provided with an annular convex portion 36 for placement on the reel stand, which is integrally formed on the lower surface of the lower flange 2 at the outer periphery of the reel shaft insertion hole 3. It is fitted into the insertion hole 37.

When the tape cassette is used, the reel shaft (none of which is shown) of the reel base inserted from below into the reel base insertion hole 37 is inserted into the reel shaft insertion hole 3 and engaged. At the same time, the entire tape reel is rotated by the reel stand while being lifted up against the compression coil spring 33 by the reel stand;
Since the convex portion 34a of the reel holder 34 made of synthetic resin can be pressed against the central upper surface of the highly wear-resistant metal plate 24, wear of the metal plate 24 due to rotation of the tape reel can be prevented. Therefore, the tape reel has high durability and reliability.

That is, in the conventional tape reel shown in FIG. 6, the convex portion 34a of the reel presser 34 is pressed against the central upper surface of the circular bulge 13 formed integrally with the upper flange 7. , the synthetic resins come into contact with each other, and the central upper surface of the circular bulge 13 tends to wear out quickly due to rotation of the tape reel.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various effective modifications can be made based on the technical idea of the present invention.

Furthermore, the present invention is not limited to tape reels used in tape cassettes for video tape recorders, but can be applied to various reels used by winding various tapes and films.

[0023]

[Effects of the Invention] The present invention can reduce the roundness of the tape winding surface, which is the outer peripheral surface of the outer cylindrical portion of the hub, without causing any distortion.
The upper flange can be accurately and reliably positioned relative to the hub in both the radial and circumferential directions.

[0024]

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part of a tape reel according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the main parts shown in FIG. 1.

FIG. 3 is a longitudinal sectional view of the entire tape reel shown in FIG. 1;

FIG. 4 is a sectional view taken along line AA in FIG. 3;

FIG. 5 is an exploded perspective view of a conventional tape reel.

6 is a vertical sectional view of the entire tape reel shown in FIG. 5; FIG.

[Explanation of symbols]

1 Hub 2 Lower flange 3 Reel shaft insertion hole 4 Inner cylindrical part 4a Upper end surface of inner cylindrical part 4b　　　　Outer peripheral surface of the inner cylindrical part 5 Tape winding surface 6 Outer cylindrical part 7 Upper flange 16 Recessed part 17 Rib 18 Locking part

Claims (1)

[Claims] Claim 1: A hub and a lower flange provided at the lower end thereof are integrally molded from synthetic resin, and the hub has an inner cylindrical part whose inside is formed into a reel shaft insertion hole, and an outer peripheral surface of which is a tape winding surface. In the tape cassette, a concave portion is provided on the outer circumferential surface of the inner cylindrical portion of the hub, and an upper flange molded from synthetic resin is welded to the upper end surface of the inner cylindrical portion of the hub. A rib having a C-shape is integrally formed on the lower surface of the upper flange, and a pair of locking portions protruding inward from the rib are provided at the open end of the rib. When placed on the upper end surface of the inner cylindrical portion of the hub, the ribs are fitted into the outer peripheral surface of the inner cylindrical portion and the pair of locking portions are locked in the recesses. tape reel.