JPS626618Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a magnetic tape cartridge characterized by a brake means for a tape reel mounted within a main body case.

In other words, a video magnetic tape cartridge is equipped with a brake means for preventing the tape reel mounted in the main body case from unexpectedly idling due to vibration when not in use. As the reel brake means, a type in which a lock pawl attached to the main body case is engaged with engaging teeth formed on the outer periphery of the lower flange of the tape reel is widely used. However, this type has problems in that it requires a large number of parts and that it is troublesome to assemble the lock pawl to the main body case so as to urge it into engagement with the engaging teeth.

Therefore, in order to solve this problem, another method is proposed in which the tape reel is elastically biased downward by a spring, and the unevenness formed on the bottom surface of the tape reel is directly engaged with the unevenness formed on the inner bottom surface of the case. A tape reel has been proposed in which the tape reel is slightly lifted against a spring and disengaged when loaded into the video unit. For example, this can be seen in Japanese Utility Model Application Publication No. 18023/1983.
This direct engagement type has the advantage of fewer parts and is easier to assemble, but the problem is that when the tape reel comes off the inner bottom of the case, it will shift laterally and come out of the correct engagement state. Situations occur. In such a case, the tape reel will be held in a tilted position and the magnetic tape will not be drawn out smoothly from the tape reel the next time it is loaded into the video unit.
There was a risk that this would lead to trouble.

Focusing on this fact, this invention uses the above-mentioned direct engagement type of reel brake means to fully utilize its advantages, while also reliably preventing troubles such as the tape reel being held in an incorrectly engaged state. Its feature is that even if the tape reel lifts off the inner bottom of the case and moves outward, the tape reel can be moved toward the center of rotation by the guiding action using the inclined surface. The purpose is to ensure that rotation is always prevented in the correct engagement state.

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

1 and 2 illustrate a magnetic tape cartridge for video. The main body case 1 is constructed by screwing together the upper and lower cases 2 and 3 in a lid-like manner, and has tape reels 4 and 4 on the left and right sides of the inside.
is attached so that it can rotate freely. The magnetic tape 5 wound on these tape reels 4 is
After being led out to the front of the case, it is wound onto the other reel 4. There is a front cover 6 on the front of the main body case 1.
It is pivoted so that it can be opened and closed, and when not in use, the front cover 6 closes the front of the case to protect the magnetic tape 5 led out to the front of the case, and when loaded into a video deck, the front cover 6 opens to protect the magnetic tape 5. The tape 5 can be pulled out from the front of the case.

In FIG. 3, the tape reel 4 has an upper flange 8 and a lower flange 9 connected to a bubble 7.
It is mounted on the through holes 10, 10 bored on the left and right sides of the lower case 3, and the lower end protrusion 7a of the hub 7 is attached to each through hole 1.
0 is involved. Each tape reel 4 is biased downward by both free ends of a leaf spring 12 fixed to the top surface 1a of the case.

Now, as a brake means for each tape reel 4, a large number of engagement grooves 13 are formed radially at a small phase pitch on the peripheral edge of the through hole 10 on the inner bottom surface 1b of the case, and on the lower surface of the lower flange 9 of the tape reel 4. 3
The basic structure is such that the engagement protrusions 14 are formed radially, and the engagement grooves 13 and the engagement protrusions 14 engage vertically facing each other. The amount of protrusion of the engagement protrusion 14 is set to be smaller than the depth of the engagement groove 13, so that the outer periphery of the lower surface of the lower flange 9 is stably received and supported by the inner bottom surface 1b of the case. Further, the distance from the reel center to the outer end of the engagement protrusion 14 is set smaller than the distance from the center of the through hole 10 to the outer end of the engagement groove 13, as shown in FIG. is located concentrically with the through hole 10, the engagement groove 13
A gap g is made to exist between the outer end of the engaging protrusion 14 and the outer end of the engaging protrusion 14.

In addition, the reel brake means of the present invention forms guiding inclined surfaces 15 and 16 that face each other in parallel at the outer end of the engaging groove 13 and the outer end of the engaging protrusion 14, respectively. This is characterized in that the tape reel 4 is slid into the center of the through hole 10 by a guiding action. Incidentally, guide slopes 17 and 18 having similar functions are also formed on the inner circumferential edge of the through hole 10 and the outer circumference of the lower end protrusion 7a of the hub 7 so as to face each other in parallel with a gap g'. . Note that the mounting positions of the above-mentioned engaging groove and the engaging protrusion may be in a positional relationship opposite to that of the embodiment. Further, the engagement protrusion in the above embodiment is not limited to a protrusion,
Any engagement protrusion that can engage with the engagement groove, such as a spherical protrusion, is sufficient.

According to the magnetic tape cartridge having such a structure, the tape reel 4, which is elastically biased downward by the plate spring 12 when not in use, is connected to the engagement groove 13 and the engagement protrusion 1.
4, the rotation is biased to lock, and the magnetic tape 5 becomes loose within the main body case 1.
The magnetic tape 5 does not come loose from the front of the case. When the main body case 1 is loaded onto a video deck, a member on the deck side pushes each tape reel 4 upwardly through the through hole 10 against the leaf spring 12. As a result, the above-mentioned lock is released and the tape reel 4 can freely rotate.

If the magnetic tape cartridge is subjected to shock or vibration when not in use, or when loaded into a video deck, the tape reel 4 may be damaged on the inner bottom surface 1b of the case.
Even if the engagement protrusion 14 comes into contact with the outer end inclined surface 15 of the engagement groove 13, the leaf spring 12
Each reel 4 is moved toward the center by the pushing down action of the slanted surfaces 15 and the guiding action of these inclined surfaces 15 and 16. Therefore, the situation where the engagement protrusion 14 rests on the inner bottom surface 1b of the case, that is, when the reel 4 is pressed and held by the leaf spring 12 in a tilted defective state, can no longer occur.

As explained above, the reel brake means according to this invention is of a direct engagement type in which an engagement groove 13 and an engagement protrusion 14 that engage with each other are provided on the inner bottom surface 1b of the case and the lower surface of the tape reel 4. As a result, the number of parts is reduced and assembly workability is improved. In addition, since the guide slopes 15 and 16 are formed oppositely at the outer ends of the engagement groove 13 and the engagement protrusion 14, the tape reel 4 may become It is possible to reliably prevent the structure from being held in a loosely engaged state, and the structure is simple and complete.

Moreover, a gap g is created between the outer end of the engagement groove 13 and the engagement protrusion 14 when the tape reel 4 is positioned concentrically with the through hole 10 formed in the bottom wall of the case. Therefore, within the range of this gap g, the tape reel 4 can freely move in the radial direction on the through hole 10, and the drive shaft on the deck side moves within the through hole 10.
Even if the tape reel 4 is guided in a misaligned state at 0, the tape reel 4 is moved in the radial direction so that the drive shaft reliably engages with the tape reel 4, ensuring reliable operation.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of a magnetic tape cartridge to which the present invention is applied, and FIG. 2 is a partially cutaway side view thereof. FIG. 3 is an enlarged longitudinal sectional front view of the main parts. Fig. 4 is a plan view showing the engagement groove on the inner bottom surface of the case, which is one of the constituent members of the present invention, and Fig. 5 is a plane view showing the engagement protrusion on the bottom surface of the tape reel, which is one of the constituent members of the present invention. FIG. 6 is a plan view showing the state of engagement between the engagement groove and the engagement protrusion. 1...Main case, 1a...Inner top surface of the case, 1
b... Inner bottom of the case, 4... Tape reel, 5...
...Magnetic tape, 6...Front lid, 7...Tape reel hub, 8...Tape reel upper flange, 9...
...Lower flange of tape reel, 10...Through hole, 1
2... Spring, 13... Engagement groove, 14... Engagement protrusion, 15, 16... Guide slope.

Claims (1)

[Scope of utility model registration request] In a magnetic tape cartridge in which a through hole 10 is formed in the bottom wall of the main body case 1, and a tape reel 4 is rotatably attached to the main body case 1 by positioning it above the through hole 10, the tape reel is attached to the main body case 1. 4 is fitted with a spring 12 that elastically biases the tape reel 4 downward, and is engaged with an engagement groove 13 that engages with the peripheral edge of the through hole 10 on the inner bottom surface 1b of the case and the lower surface of the lower flange 9 of the tape reel 4. The protrusions 14 are each formed radially, and a gap g exists between the outer end of the engagement groove 13 and the engagement protrusion 14 when the tape reel 4 is positioned concentrically with the through hole 10.
A magnetic tape car characterized in that guiding slopes 15 and 16 are respectively formed on opposing outer ends of the engaging groove 13 and the engaging protrusion 14 for sliding and guiding the tape reel 4 toward the center of rotation. Tritsuji.