JPS6017101Y2 - magnetic tape cassette - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a magnetic tape cassette, and more specifically, a pair or one spool for winding or unwinding the magnetic tape is provided in the cassette, and the spool is attached to the cassette case. The present invention relates to a magnetic tape cassette which is rotatably supported and whose spool is rotated via a drive reel shaft of a tape recorder to cause the magnetic tape to run in a winding direction or a rewinding direction.

In a conventional magnetic tape cassette of this kind, in order to rotate the spool, a drive member is interposed between the spool and the drive reel shaft on the tape recorder main body side, and the rotation of the drive reel shaft is temporarily controlled by the drive member. It is customary to transmit and rotate the spool by means of the drive member.

However, if the drive member and the drive reel shaft on the tape recorder main body side become eccentric due to various reasons, the engagement between the drive member and the drive reel shaft will periodically press against each other, resulting in severe torque unevenness. In some cases, this torque becomes extremely large, or due to a collision between the member and the reel shaft, the torque becomes large, causing the spool to rotate at an uneven speed (uneven rotation) or become unable to rotate, which has the drawback of not being able to rotate accurately. .

Conventionally, orthoham couplings have been used to overcome the drawbacks caused by eccentricity, but the structure becomes more complex, the number of parts increases by three times, the structure becomes larger, it cannot be made thinner and smaller, and it is expensive. There was a drawback.

This invention was made in view of these circumstances,
It is possible to absorb the mutual eccentricity between the drive reel shaft on the tape recorder body side and the bearing section on the cassette side, and it is possible to prevent uneven rotation or inability to rotate, and to rotate the spool accurately. The object of the present invention is to provide a magnetic tape cassette which has an extremely simple structure, has a small number of parts, is small and thin, has no constantly moving parts, has a long life, and is inexpensive.

Therefore, the present invention integrally forms a driven gear with a spool for winding or unwinding the magnetic tape within the cassette body, and also has a gear shaft of the driven gear pivotally supported at one end of a swing arm. A driven gear shaft protruding downward from the swinging arm is loosely fitted into a long hole in the cassette body, while a driving gear shaft that interlocks with the drive reel shaft on the tape recorder main body side is fitted into a cylindrical bearing portion at the other end of the swinging arm. A driving gear that meshes with the driven gear is fixed to the driving gear shaft, and an annular clearance is formed between the cassette main body and the cylindrical bearing part, so that the parts of the tape recorder main body are It is an attempt to achieve the above-mentioned intended purpose by absorbing all errors in assembly, errors in cassette parts, assembly errors, and differences in the setting position of the cassette in the main body.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, using an example in which the present invention is applied to a VTR magnetic tape cassette for long-term recording and playback.

FIG. 1 is a schematic plan view of a VTR magnetic tape cassette for long-time recording and playback according to the present invention. In the figure, 1 is a cassette body, and as shown in FIG.
A small lower case 2 of a size corresponding to the cassette mounting part of the TR and a large upper case 3 are integrated.

An opening 7 is formed between the pair of guide rolls 4.5 vertically installed in the lower case 2 to pull out the magnetic tape 6 toward the loading side of the VTR, and a horizontal partition 8 between the lower case 2 and the upper case 3 is provided with an opening 7. A pair of alignment bearing mechanisms (corresponding to so-called shaft joints) 10 and 11 are provided which fit and bear the drive reel shaft 9 of the VTR.

A pair of spools 12 and 13 are disposed within the upper case 3 and move with the alignment bearing mechanism 10.degree. 11, respectively, and a large amount of tape 6 is wound around the spools 12 and 13.

Driven gears 14 and 15 are integrally formed on each of the spools 12.13, as shown in FIG. A swinging arm 29 is arranged to be movable in the horizontal direction within a small range to absorb eccentricity between the rotating body and the rotating body.
A driven gear shaft 16 that is pivotally supported at one end and projects downward from the swing arm 29 is connected to a horizontal partition 8 in the cassette body 1.
It fits loosely into the elongated hole 8a.

The magnetic tape 6 wound around the pair of spools 12 and 13 in the upper case 3 is guided to the pair of guide rolls 4 and 5 in the opening part 7 of the lower case 2 by guide members 17 and 18. 19.2
0.21.22.23.24.

A total of four guide members 18, 19, 22, and 23 among the guide members 17 to 24 are disposed perpendicularly to the slope of the inclined table 25, and the magnetic tape 6 is attached to the guide members disposed in an inclined manner. 18, 19, 22, and 23 to guide between the upper and lower cases 3 and 2.

The alignment bearing mechanisms 10 and 11 also include the driven gear 1.
Driving gears 26 and 27 that mesh with 4 and 15 are provided,
The alignment bearing mechanism 1 rotates and stops the drive reel shaft 9 of the VTR.
From driving gear 26.27 to driven gear 14 via 0.11
, 15 to rotate and stop the spools 12, 13 in the upper case 3.

Next, the specific structure of the alignment bearing mechanism 10.11, which is the core of the present invention, will be described with reference to FIGS. 3 to 5.

However, since the structures of the pair of bearing mechanisms 10 and 11 are the same, only the structure of one alignment bearing mechanism 10 will be described here.

Reference numeral 28 denotes a driving gear shaft that interlocks with the driving reel shaft 9 of the VTR, and the swing arm 2 is disposed at an intermediate portion of the driving gear shaft 28.
9 is fitted with a cylindrical bearing portion 29a at the other end.

The drive gear shaft 28 is rotatably supported on the horizontal partition 8 of the cassette body 1 via the bearing 29a.

A driving gear shaft 28 protruding above the horizontal partition 8
The above-described driving gear 26 is fixed to the upper end, while a rotating body 30 is fixed to the lower end of the driving gear shaft 28 that projects downward from the horizontal partition 8.

The rotating body 3θ has similar uneven portions 30a formed at its center to engage with the plurality of uneven portions 9a of the drive reel shaft 9 and transmit the rotational force thereof.

Furthermore, an annular clearance 31 is formed between the horizontal partition part 8 of the cassette main body 1 and the cylindrical bearing part 29a.

This clearance 31 is provided by the cylindrical bearing part 2 in the partition part 8.
This is necessarily formed by forming in advance a loose fitting hole larger than the outer diameter of the bearing portion 9a, and inserting the bearing portion 29a into this loose fitting hole.

Further, a bearing portion 2 protrudes downward from the horizontal partition portion 8.
A retaining ring 32 is provided at 9a for preventing vertical movement and allowing only horizontal movement within the clearance 21.
This retaining ring 32 prevents the swing arm 29 from being removed.

Furthermore, the elongated hole 8a into which the driven gear shaft 16 is loosely fitted is formed in the direction of the driving gear shaft 28, as is clear from FIG.

Next, the operation of the magnetic tape cassette constructed as described above will be described.

Now, when setting the cassette body 1 in the cassette mounting part of a VTR, there may be a connection error between the cassette itself and the VTR, a manufacturing error in the cassette itself, or a manufacturing error in the VTR, and the drive reel shaft 9 and driving gear shaft 28 may Even if the shaft center of the cassette body 1 is eccentric, when the cassette main body 1 is set in the cassette mounting part of a VTR, the drive reel shaft 9 on the VTR side is connected to the lower end of the drive gear shaft 28 through the opening 2a at the bottom of the lower case 2. When fitted into the uneven portion 30a, the shaft 28 and the cylindrical bearing portion 29a at the other end of the swing arm 29 are displaced within the annular clearance 31 in any direction of the entire outer circumferential direction of the bearing portion 29a. Since the axes of each shaft 9, 28 are aligned, the axes of the drive reel shaft 9 and the drive gear shaft 28 are aligned in the vertical direction as shown in FIGS. 4 and 6, and Since the driven gear shaft 16 is also displaced integrally with the displacement of the driving gear shaft 28, both gears 26, 14 always maintain a proper meshing state, and as a result, the rotational force and rotational speed of the driving reel shaft 9 can be adjusted to each other. Spool 12 via gear 26.14
This ensures that the spool 12 is prevented from rotating at an uneven speed and from being unable to rotate.

As described in detail above, the present invention integrates the driven gear 14 with the spool 12 that winds the magnetic tape 6 in the cassette body 1 so that it can be wound up or unwound, and the gear shaft 16 of the driven gear 14 is connected to the spool 12. A driving gear shaft 28 that is pivotally supported at one end of the swinging arm 29 and interlocks with the drive reel shaft 9 on the tape recorder main body side is mounted on a cylindrical bearing portion 29a at the other end of the swinging arm 29.
A driving gear 26 that meshes with the driven gear 14 is fixed to the driving gear shaft 28 so that the distance between the shafts of the driving gear 26 and the driven gear 14 is constant within the cassette body 1. Therefore, the mutual eccentricity between the drive reel shaft 9 on the recorder main body side and the bearing section on the cassette side can be absorbed by the clearance 31 and the elongated hole 8a. Since the engagement with the spool 12 can always be maintained constant, it is possible to prevent the spool 12 from rotating at an uneven speed or being unable to rotate, and the spool 12 can be rotated accurately at all times, which causes image and sound disturbances in VTRs. Never.

Furthermore, since an orthoham joint or the like having a complicated structure is not used, the structure is extremely simple and has various excellent effects such as being inexpensive.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view of a VTR magnetic tape cassette for long-term recording and playback according to the present invention, and Fig. 2 is a schematic plan view of the VTR magnetic tape cassette for long-term recording and playback according to the present invention.
Figure 3 is a cross-sectional view taken along the line ■-■ in Figure 1;
Figure 4 is an enlarged sectional view of the main part of Figure 3, and Figure 5 is
-V line arrow view and FIG. 6 are enlarged sectional views of essential parts for explaining the centering action of the present invention. 1...Cassette body, 8a...Long hole,
9... Drive reel shaft, 12... Spool, 14... Driven gear, 16... Driven gear shaft, 26... Drive gear , 28...
Driving gear shaft, 29... Swinging arm, 29a...
...Cylindrical bearing part, 31... Clearance.

Claims (1)

[Scope of utility model registration request] A driven gear 14 is integrally formed with a spool 12 for winding or rewinding the magnetic tape 6 within the cassette body 1, and a gear shaft 16 of the driven gear 14 is pivotally supported at one end of a swinging arm 29. At the same time, a driving gear shaft 28 that interlocks with the driving reel shaft 9 on the tape recorder main body side is rotatably supported on a cylindrical bearing portion 29a at the other end of the swing arm 29, and the driving gear shaft 28 is connected to the driven gear. Driving gear 26 meshing with 14
A magnetic tape cassette characterized in that the distance between the shafts of the driving gear 26 and the driven gear 14 is constant within the cassette body 1.