JPS5923265Y2 - Tape reel for video cassette tape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape reel for a video cassette tape, and particularly to a tape reel with an improved tape end holding portion.

Generally, a tape reel for a video cassette tape has a restriction plate or flange at each end in the axial direction of a bubble around which the tape is wound, and these days, the tape reel is made exclusively of plastic.

Therefore, in order to hold the tape end with such a tape reel, a part of the outer peripheral surface of the bub is cut out to create a recess that is deep in the radial direction and extends in the axial direction, and the tape is inserted into this recess. After inserting the terminal, the fixing member is pushed in with a snap to close the recess.

Once the tape has been held, the outer wall surface of the fixing member becomes part of the outer peripheral surface of the bubble.

However, with conventional products that simply provide tape holding recesses and push plastic fixing members into them, the bubble diameter inevitably becomes thicker, and the length of tape that can be wound within the same flange diameter is short and the longest The recording and playback time is limited, and the larger diameter of the bubble requires extra resin, making it uneconomical.

Basically, in view of the above, this proposal eliminates the drawback that the bubble diameter was thicker than originally necessary for the holding part of the tape terminal, and provides a rational configuration that allows the bubble diameter to be as small as possible. It's a serious thing.

A preferred embodiment of the present invention is shown in FIGS. 1 to 4. First, for convenience of explanation, the description will begin with the known construction or the parts that are generally common to this type of tape reel.

The bubble 1 is formed by integrally molding one flange 2a of plastic at one end in the axial direction, but the other end is a free end, and the other flange 2b is molded separately of plastic.
is attached to this free end by any suitable method, such as sonic welding or snap-locking means.

The one shown is an example of an ultrasonic welding method, in which a plurality of bosses 3 are erected at appropriate angular intervals on the free end of the bub.
The separate flange 2b is positioned so as to pass through the corresponding bore 5 of the separate flange 2b, and the flange is fixed by crushing the tip of the boss protruding on the front side of the flange using a well-known method.

In this case, at the center of the free end of the bubble, there is a small protrusion 5 that comes into contact with a known elastic presser piece (not shown) on the cassette case side, and the flange 2b is inserted through the central opening 6 of the separate flange 2b. It is designed to come out to the front side.

Inside the hub 1 there is an axial blind hole 7 which is open at the end that is not visible in FIG. Ribs 8 are provided at angular intervals.

These blind holes 7 and ribs 8 are made by taking a cross section along the line III-III in FIG. 2 and the line III-III in FIG. This is clearly shown in FIGS. 3 and 4 when viewed from above, and as is well known, this means that the reel retaining shaft (not shown) of the tape transport of the cassette chip is inserted into the blind hole 7. , and the rib 8 is engaged with the rib on the engaging shaft side, so that rotational force is transmitted between the reel and the retaining shaft.

In the illustrated case, the so-called β-max type tape knoll has six ribs 8 at 60° intervals, but in the so-called VH3 type, there are nine ribs 8 at 40° intervals.

In either case, the ideas on the merits described below can be applied without any problem.

When viewed from the front, the wall portion 9 in which the blind hole (reel holding shaft fitting hole) 7 and the ribs 8 are provided forms a central cylindrical portion as clearly shown in FIG.

In this case, for reasons that will be explained in detail later, the wall thickness of the rib 8 portion is approximately the same as that of the wall portion 10 where no rib is provided, and a large depression 11 is formed on the back side of the rib 8. Therefore, when viewed from above as a whole, it has a chrysanthemum-like shape (as seen in the cross-sections in Figures 3 and 4).
Conventionally, since the knob 8 is not lightened (because there is no recess 11), the central cylindrical portion literally has a continuous cylindrical shape, as shown by the imaginary line 9' in FIG.

And generally, the central cylindrical part 9 (the conventional one is 9
'), an outer cylindrical portion 12 around which the tape is wound is disposed concentrically on the outer peripheral surface 12a, and radial ribs 13...
・Connected and reinforced with etc.

The tape end holding hole or holding depression 14 is first formed by cutting a part of the circumferential surface of the hub outer cylindrical portion 12 in the axial direction at appropriate circumferential angular intervals to form an inlet 15, and from this inlet radially inward. It is formed by providing a space for.

On the other hand, the tape fixing member 16 has an outer surface portion 17 that closes the inlet 15 and whose outer surface matches the curvature of the hub outer circumferential surface 12a and becomes a part of the hub outer circumferential surface, and a locking member 18 that protrudes from the inner surface in the radial direction. It is machined from wood and molded from a plastic material with appropriate elasticity (generally the same material as the hub material).

The locking members 18 are generally provided as a pair of legs 19 extending radially inward and folded back into a hook shape, facing in opposite directions. It is configured to snap onto the back surface (inner surface) of the outer peripheral surface edge 21 of the hub.

Therefore, as can be seen from the installation work described later, the length l of this leg cannot be made too short in order to sufficiently maintain the tape holding force and the adhesion force to the outer cylinder part 12. .

This is because the elasticity is reduced.

However, conventionally, a tape holding hole large enough to accommodate the leg 19 to the locking member 18 was formed on the outside of the central cylindrical portion 9' in the radial direction, so as the length l of the leg 19 increases, the tape holding hole becomes larger. The radial depth of the holding hole also increased, and therefore the diameter of the outer circumferential surface 12a also increased, causing the defects mentioned at the beginning.

In response to this, this proposal provides the following solutions.

To put it simply, the above-mentioned engagement rib 8 with the reel engagement shaft
The recess 11 with its back removed is used as a part of the tape holding hole, and at least the radially inward protruding portion of the locking means 18 of the fixing member is accommodated therein.

Hereinafter, the features of this embodiment will be further clarified while following the tape terminal holding work.

In this case, the fixing member 16 is provided with a pair of circumferentially spaced locking means 18.18 projecting radially inward from the back surface of the outer surface portion 17, so that
The back surface portion 22 of the tape holding hole 14, which has a depth radially inward following the inlet 15 cut in accordance with the circumferential length of the outer surface portion 17 of the fixing member, is also provided with a recess 11. 11.

As mentioned above, the locking means 18 of the fixing member 16 is in the form of a hook in this case, with both hook tips 20.2
The circumferential length between 0 and 0 is longer than the circumferential length of the inlet 15.

The circumferential length between the radially inwardly most protruding parts 19' and 19' where each leg 19.19 is folded back to form a hook is approximately the same as the circumferential length between the recesses 11.11 on the rear surface of the rib. It has become a degree.

Then, the end of the tape T to be fastened is put into the tape holding hole 14, the tape fixing member 16 is made to face the holding hole entrance 15 from the outside in the radial direction, and both the locking means 18 are placed above the tape end. As the locking means 18.1 is pushed in, each locking means 18.1
The hook tips 20.20 of No. 8 come into contact with both edges 21.21 of the entrance of the holding hole due to the dimensional relationship at the tip, and as the push is continued, both hook tips 20.20 are locked together as shown in the third figure. The leg 19. The part after the folded part of the leg 19 bends due to its own elasticity and moves forward.

Then, the hook tip 20.20 is connected to both edges 21.20 of the entrance 15.
21, the elastic restoring force of the locking legs 19, 19 due to the bending causes both hook tips 20.2
0 rebounds and comes into contact with the back side of both artificial edges and is locked.

At this time, from the above dimensional relationship, the vicinity of the radially inward protruding end 19' of both locking legs is located in the recess 11 of the corresponding rib 8.
It is possible to go inside (as shown in Figure 4).

The tape T is held under pressure between each surface of the fixing member 16 and each surface of the holding hole 14 that are in contact with each other, and
The remaining length extends from the gap between the entrance 15 and the fixing member on one side edge.

As shown in FIG. 4, when the tape end holding is completed, a portion of the length l of the locking leg 19 of the fixing member is in the recess 11.
By entering the bubble, it bites into the central cylindrical portion 9, so the radial distance between the central cylindrical portion 9 and the outer cylindrical portion 12 can be made shorter than before, and the diameter of the bubble can be reduced. can be made relatively small in diameter.

In addition, understanding the above, in order to fulfill the gist of the present invention, the back of the rib 8 in the part unrelated to the tape holding hole 14 should not be thinned out, but should be recessed like the conventional one shown by the imaginary line 9'. 11
It can be seen that the gap 23 between the central cylindrical portion 9 and the outer cylindrical portion 12 may be solid.

However, it is preferable that the back of each rib 8 is also thinned out to have substantially the same thickness as the other cylindrical partial wall 10, as shown in the figure.

This is because differences in groove path length and resin flow rate are less likely to occur during injection molding, and distortion in the molding amount can be prevented and dimensional accuracy can be improved.

Furthermore, it should be understood that the present invention does not directly define the structure of the locking means 18 itself. For example, even if a hook-shaped member as shown in the figure is used, The other side can be used as a tab 18' that is simply hooked onto the edge 21 of the corresponding entrance 15. First, hook this tab 18' on the edge 21, and then attach the fixing member 16 using the end as a fulcrum. The other locking means 18 may be pushed in by slightly turning the locking means 18 and snap-locked.

In this case, only one recess 11 on the back of the rib 8 is sufficient.

Note that the tape terminal is not shown in FIG. 5 for the sake of simplicity.

In any case, according to the present invention, the back of the rib for engaging with the engaging shaft, which is always provided in a tape reel for a video cassette tape, is made into a depression and used as part of the tape holding hole, and the locking means is inserted in the depression. Because we have adopted a rational configuration that accommodates a portion of the length inward in the radial direction, compared to conventional bubbles in which the diameter of the bubble must become thicker due to the existence of the tape holding part. , the bubble diameter can be kept small, the length of the tape to be wound can be increased for the same flange diameter, and the amount of resin required for molding can be reduced, which is a remarkable effect.

[Brief explanation of the drawing]

Fig. 1 is a partially fragmented exploded perspective view of an embodiment of the present invention, Fig. 2 is a vertical sectional view taken along the line I-II of Fig. 1, and Figs. 3 and 4 respectively show tape end holding work. Middle, enlarged cross-sectional view of main parts along line I-III in Figure 2 after work, Figure 5
The figure is a schematic configuration diagram of the main parts of another example of the tape terminal holding configuration. In the figure, 1 is a buff, 2a and 2b are flanges, 7 is a reel,
Shaft engaging blind hole, 8, reel shaft engaging rib, 9, central cylindrical part, 11, recess extending in the axial direction on the back of the rib, 12, outer cylindrical part, 14, tape holding hole, 15, inlet, 16 is a fixed member,
Reference numeral 18 indicates the locking member thereof, and reference numeral 22 indicates the inner surface portion of the holding hole.

Claims (1)

[Claims for Utility Model Registration] A part of the outer peripheral surface of a plastic bubble having flanges at both ends is cut in the axial direction across a predetermined angle in the circumferential direction to form an entrance for a tape holding hole having a depth in the radial direction. , an outer surface portion that blocks the inlet and becomes a part of the outer peripheral surface of the bub, and a locking means that extends radially inward from the outer surface portion and snaps into the tape holding hole. A tape reel for a video cassette tape having a plastic fixing member, the reel having a plurality of reel shaft engaging members extending radially inward and extending in the axial direction provided on the inner wall surface of a blind engagement hole inside a bubble that accommodates the reel engaging shaft. Among the joining ribs, at least one of the ribs is thinned out to form a recess in the axial direction, and the recess is used as a part of the radially inward inner surface of the tape holding hole, and the recess is formed in the radial direction of the fixing member. A tape reel for a video cassette, characterized in that at least a portion near the leading edge of the tape reel is accommodated.