JPS5923263Y2 - Tape clamp structure for hub in magnetic tape cartridge - Google Patents

Description

[Detailed Description of the Invention] This invention is an improvement to the tape clamp structure that locks the end of a magnetic tape to a bubble built into a magnetic tape cartridge.

In a magnetic tape cartridge as shown in FIG. 1, a pair of plastic bubbles 3, 3 are installed inside the main body case, and each bubble 3, 3 is attached to the end of the magnetic tape 4 (usually the end of the leader tape). However, there was a problem with the tape clamp structure for this bub 3.

In other words, the typical conventional tape clamp structure is
Examples include those shown in FIG.

This involves forming an inwardly expanding fitting hole 10 at one location on the outer circumferential surface of the bub 3, and forcefully press-fitting the cylindrical clamp piece 9 into the fitting hole 10 by sandwiching the end of the tape. This structure utilizes elastic deformation between the clamp piece 9 and the fitting hole 10 to clamp the end of the tape.

In this case, in order to allow the clamp piece 9 to be press-fitted, the left and right opening edges of the fitting hole 10 are arranged on the outwardly expanding inclined guide surface 2.
5 and that the surface curvature of the clamp piece 9 is significantly different from that of the outer peripheral surface of the bub, a large gap a is created between the opening edge of the fitting hole 10 and the clamp piece 9.

Therefore, when the magnetic tape 4 is wound around the bubble 3, the magnetic tape 4 fills the gap a over its entire width at the beginning of winding.
The tape gets stuck in and causes wrinkles, which spreads and causes unevenness in the area where the tape is wrapped between the eyebrows.

Also, even after clamping, the end 4a of the magnetic tape 4 remains on the hub 3.
The tape protrudes largely onto the outer circumferential surface of the tape, further aggravating irregularities in tape winding.

Conventionally, as shown in FIG. 7, a method has been widely adopted in which a π-shaped clamp piece 9 whose surface has the same curvature as the outer peripheral surface of the hub is used, and this is forcibly press-fitted into the fitting hole 10 of the hub 3. Ta.

However, since this also involves forcibly press-fitting the clamp piece 9 into the fitting hole 10, the more effort is made to make fitting easier, the more a gap a is created at the opening edge of the fitting hole 10.

The ends of the tape may also protrude. In addition, as with the previous example, such a clamp piece has a large amount of elastic deformation, so it is prone to deterioration and fatigue due to temperature conditions and repeated tape tension, and the tape clamping function deteriorates over time. In this case, magnetic tape 4 is connected to hub 3.
There were also times when I would release karanuki.

These conventional drawbacks arise from the fact that the clamp piece itself is forcibly pushed into the fitting hole 10 of the hub 3 while being largely elastically deformed.

In order to solve such problems, the applicant first proposed the eighth
We proposed a tape clamp structure as shown in the figure.
No. 0-50023).

In this case, the fitting hole 10 recessed in the hub 3 is slightly expanded outward and the protrusion 26 is provided on the inner bottom surface thereof, and the clamp piece 9 has a solid semi-cylindrical cross section and has the protrusion 26 on its tip surface. The structure has a recessed hole 27 that fits into the strip 26.

According to this improved structure, the clamp piece 9 fits smoothly into the fitting hole 10, and the protrusion 26 fits into the recessed hole 2.
7, the formation of a gap at the opening edge of the fitting hole 10 can be prevented as much as possible, but the following problems still remain.

That is, when the magnetic tape 4 was sandwiched between the elastic fitting portion of the protrusion 26 and the recessed hole 27 having a small curvature, it was forcibly stretched at this portion, making it easy to cut.

Furthermore, since the clamp piece 9 is solid, the elastic deformation caused by the forcible fitting between the protrusion 26 and the recessed hole 27 spreads to the outer surface 14 of the piece, and the outer surface 14 of the piece still remains
4 and the hub outer circumferential surface 15 tended to have a gap or a step difference.

Focusing on this fact, this invention loosely fits the clamp piece into the fitting hole of the hub with the tape end sandwiched in between, and the tip side part of the piece is inserted into the inner part of the fitting hole. The end of the tape is clamped in the fitting hole by forcibly deforming it elastically, and the elastically deformed state of the clamp piece is maintained by elastic fitting between the protrusion provided in the piece and the recessed hole. This is an attempt to eliminate all the drawbacks of the conventional technology at once.

The details will be explained below with reference to the drawings.

FIG. 1 illustrates a standard Philips type magnetic tape cartridge.

The main case 1 of this is the upper and lower plastic case la
, lb are screw-bonded in a manner that the lids fit together, and hubs 3, 3 made of polyacetal resin are rotatably installed inside each drive shaft insertion hole 2, 2 provided on the left and right sides of the central portion.

Then, both ends (leader tape portions) of the magnetic tape 4 are locked onto each hub 3 and wound, and the magnetic tape 4 is fed out from one of the supply hubs 3, and an erasing head is inserted into the front surface of the main body case 1. The tape travels through the opening 5, the recording/reproducing magnetic head insertion opening 6, and the pinch roller insertion lower part in this order, and is wound onto the other winding-side hub 3.

In FIG. 2, the end of the magnetic tape 4 is latched and connected to the hub 3 via a clamp piece 9, and these constituent members are as follows.

The hub 3 has a fitting hole 10 at one location on its outer peripheral surface.

This fitting hole 10 is formed concavely in the front and rear width direction of the hub 3, and the left and right inner surfaces 11, 11 of the portion closer to the entrance than the middle in the depth direction of the hole are respectively formed into outwardly expanding inclined surfaces. Further, the left and right inner side surfaces 12, 12 of the back portion are each formed as an undercut surface that is inclined to expand inward, and furthermore, the inner bottom surface 13 is formed as a flat surface.

The clamp piece 9 has good elastic deformation and is made of the same material as the hub 3, such as polyacetal resin, polyethylene resin, polypropylene resin, etc., and its outer surface 14 is formed to have the same curvature as the outer peripheral surface 15 of the hub 3. A through hole 16 is provided transparently extending in the front and rear width direction.

Then, the left and right sides 1 of the outer surface side part of the clamp piece 9
7.17 is formed in an outwardly expanding shape that closely contacts the inner surface 11.11 of the fitting hole 10, and the left and right side surfaces 1 of the tip side portion thereof.
8.18 are formed so as to be parallel to each other at a spacing slightly smaller than the left-right spacing of the middle constricted portions 19, 19 of the fitting hole 10 in the elastically restored free state.

Further, the tip wall portion 20 of the clamp piece 9 is formed in a thin shape throughout so that it is easily elastically deformed.
The distal end surface 21 of the distal end wall portion 20 is formed into a solid shape that protrudes toward the distal end in an elastically restored free state.

In addition, on the inner surface of the through hole 16, a protrusion 22 and a recessed hole 23 are formed in the left and right centers to be elastically fitted to each other and are vertically opposed in the front and rear width directions in the figure. .

Next, when using the clamp piece 9 described above to lock and connect the end of the magnetic tape 4 to the bubble 3, first, as shown in FIG. It fits into the fitting hole 10 of the bubble 3.

At this time, the tip end portion of the piece 9 passes smoothly through the intermediate constricted portion 19, 19 of the fitting hole 10 without interfering with it.

After the tip wall portion 20 of the piece 9 contacts the inner bottom surface 13 of the fitting hole 10, when a pushing force is applied to the piece 9, the tip wall portion 20 is pressed toward the outer surface 14 and becomes elastic. transformed.

This is the state shown in FIG. 4, and as a result of this elastic deformation, the left and right side surfaces 18, 18 of the piece 9 are pressed against the inner surface 12° 12 of the fitting hole 10 with the magnetic tape 4 in between, and the protrusion 22 pushes open the recessed hole 23 and is elastically fitted into it, and this elastic fitting maintains the deformed state of the tip wall portion 20, completing the locking operation of the magnetic tape 4.

In addition, the left and right inner surfaces 11° 11 of the entrance side portion of the fitting hole 10
As described above, it is convenient if the clamp pieces 9 are formed into outwardly expanding inclined surfaces so that the clamp pieces 9 can be smoothly guided and fitted, but they may be parallel.

Further, in order to make the left and right inner surfaces 11.11 outwardly expanding, they may be formed into stepped outwardly expanding inclined surfaces, as shown in FIG.

Furthermore, it is preferable that the magnetic tape 4 be clamped over the entire surface of the left and right side surfaces 18.18 of the clamp piece 9 and the left and right inner surfaces 11.11 of the fitting hole 10, but only in the portions close to the piece outer surface 14. They may be placed in close contact.

Similarly, the left and right side surfaces 18.18 of the distal end portion of the piece 9 also have the magnetic tape 4 on the left and right inner surfaces 12.12 of the rear portion of the fitting hole 10 only at the portions close to the intermediate constriction portion 19.19.
It may also be possible to put them in close contact with each other.

As explained above, according to this invention, the clamp piece 9 is inserted into the fitting hole 10 of the bubble 3 with the end of the magnetic tape 4 sandwiched therebetween, and the piece The front end portion of the magnetic tape 9 is elastically deformed and the magnetic tape 4 is sandwiched and crimped.

Therefore, the artificial side portion of the fitting hole 10 and the outer surface side portion of the clamp piece 9 are originally not elastically deformed, and
Elastic deformation at the tip end portion of the piece 9 is also absorbed by the through hole 16 and does not spread to the outer surface 14 of the piece.
To prevent the generation of a gap between the piece outer surface 14 and the opening edge of the fitting hole 10 as much as possible, and to make the piece outer surface 14 continue flush with the bubble outer peripheral surface 15 with the same curvature. I can do it.

Further, the elastically deformed state of the tip wall portion 20 of the clamp piece 9 is maintained by elastic fitting between the protrusion 22 and the recessed hole 23 inside the piece 9.

Further, the clamp piece 9 can be fitted into the fitting hole 10 without resistance.

Therefore, the magnetic tape 4 is not locally stretched and crimped between the piece 9 and the fitting hole 10, and troubles such as tape cutting and tape ends protruding outside are effectively prevented. I ended up getting it.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway plan view showing an example of a magnetic tape cartridge to which the present invention is applied, Fig. 2 is an exploded perspective view of its main parts, and Figs. 3 and 4 show the magnetic tape attached to the bubble. FIG. 6 is an enlarged plan view of a main part showing a procedure for fastening and connecting. FIG. 5 is an enlarged plan view of main parts showing another embodiment of the present invention. FIG. 6, FIG. 7, and FIG. 8 are enlarged plan views of essential parts of the conventional example. 3... Bub, 4... Magnetic tape, 9... Clamp piece, 10... Fitting hole, 11... Inner surface on the entrance side of the fitting hole, 12... Fitting hole Inner surface of the back part, 13
... Inner bottom surface of fitting hole, 14 ... Outer surface of clamp piece, 15 ... Outer peripheral surface of bubble, 16 ... Through hole, 1
7...Side surface of the outer surface side of the clamp piece, 18.
...Side surface of the tip side portion of the clamp piece, 19...Middle constriction of the fitting hole, 20...Top wall portion of the clamp piece, 21...Top surface of the tip wall portion, 22...Protrusion Article 23... Concave hole.

Claims (3)

[Scope of utility model registration request] (1) The left and right inner surfaces 11.11 of the entrance side part are outwardly expanding or parallel, and the left and right inner surfaces 12.12 of the back part are inwardly expanding.A fitting hole 10 is recessed in the front and rear width direction. It consists of a plastic bub 3, which has an outer surface 14 having the same curvature as the outer circumferential surface 15 of the bub 3, and an elastically deformable plastic clamp piece 9 in which a through hole 16 is transparent in the front-rear direction, The left and right side surfaces 17.17 of the outer surface side portion of the clamp piece 9 are shaped to closely fit the inner surface 11°11 of the fitting hole 10, and the left and right side surfaces 18.18 of the tip side portion of the clamp piece 9 are elastically restored. The clamp piece 9 has a shape that fits loosely into the inner part of the fitting hole 10 in a free state, and the tip wall portion 20 of the clamp piece 9 is elastically deformable toward the outer surface 14, and along with this elastic deformation, the tip of the piece The left and right side surfaces 18.18 of the side portions are press-fitted to the inner surface 12.12 of the fitting hole 10, and the tip wall portion 20 has protrusions 22 that are vertically opposed to each other on the inner surface of the through hole 16. A tape clamp structure for a bub in a magnetic tape cartridge is configured to be held in the above-mentioned elastically deformed state by elastic fitting between the bub and the real space 23. (2) Left and right side surfaces 18 of the tip side portion of the clamp piece 9;
18 are formed so as to be parallel to each other at a spacing slightly smaller than the left-right spacing of the middle constricted portions 19 and 19 of the fitting hole 10 in the elastically restored free state. Tape clamp structure. (3) The inner bottom surface 13 of the fitting hole 10 is formed into a flat surface, and the tip surface 21 of the tip wall portion 20 of the clamp piece 9
The tape clamp structure according to claim 2 or 3, wherein the tape clamp structure is formed into a solid shape that protrudes toward the distal end side in an elastically restored free state.