JPH0237191Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a magnetic tape cassette, and more particularly to a magnetic tape cassette provided with a relief for a member protruding inside the cassette half.

[Conventional technology]

In the past, magnetic tape cassettes used in video tape recorders (hereinafter referred to as VTRs) generally had one type of cassette size, but as magnetic recording and playback became more diverse, magnetic tapes of multiple sizes with different recording times and compatibility were introduced. Cassettes came into use.

By the way, when trying to record and play back tape cassettes of different cassette sizes on the same VTR, it is necessary to install these tape cassettes into the VTR body using a common cassette mounting mechanism. The tape cassette must be loaded so that it is centered in the cassette holder of the cassette loading mechanism. In order to load a small tape cassette in the central position in this manner, the bottom view of the tape cassette is shown in Figure 5, and the bottom view in Figure 6 is shown in Figure 6.
As shown in the schematic diagram of the cassette holder 20,
It is conceivable to provide a guide groove 21 formed in the cassette loading direction on the bottom surface of the tape cassette, and to provide a protruding centering guide 22 that fits into the guide groove 21 inside the cassette holder 20. Such a centering mechanism can be said to be a simple and reliable means.

However, in the above centering mechanism, as shown in FIG.
If the height of the centering guide 22 that fits into the guide groove on the bottom of the cassette holder 20 is low, and the cassette holder 20 is curved, the centering guide 22 will not fit into the guide groove 21 well, and the small size The tape cassette 24 is attached to the cassette holder 2
A problem occurs in which the cartridge is not loaded in the center position of 0.

Therefore, it is necessary to increase the height of the centering guide 22 and to increase the depth of the guide groove 21 provided on the bottom surface of the tape cassette, that is, on the lower half of the cassette.

By the way, in consideration of the clearance between the height H of the tape cassette and the height h of the cassette holder 20, and the degree of curvature of the cassette holder 20, it is desirable that the depth of the guide groove 21 is 3 mm or more.
Further, the thickness of the lower half of the cassette in which the guide groove 21 is formed is required to be approximately 3 mm in consideration of rigidity. For this reason, the thickness of the upper part of the guide groove 21 comes to protrude into the inside of the cassette half. When a protrusion is formed on the inside of the cassette half in this manner, the outer peripheral edge of the lower flange of the tape reel comes into contact with the protrusion, and smooth rotation of the tape reel is hindered.

Therefore, the distance between the axes of the tape reels, that is, the reel pitch, is increased to widen the interval between the lower flanges 25 of the tape reels as shown in FIG. It is possible to try to escape. However, if you expand the reel pitch in this way, the 9th
The total length L of the tape cassette shown in the figure increases,
A problem arises in that the tape cassette becomes larger.

In addition, as shown in Fig. 8, the cassette lower half 2
It is conceivable to increase the height of the lower flange 25 with respect to No. 6 by the height of the protrusion 27 so that the protrusion 27 can escape, but in this case also
A problem arises in that the overall height H of the tape cassette shown in the figure increases, resulting in an increase in the size of the tape cassette.

By the way, FIG. 10 shows a schematic cross-sectional view of a magnetic tape cassette, and as shown in FIG.
Reel presser plate spring 32 attached to the inside of 1
The tape reel 33 is pressed down. 11 and 12 show the leaf spring 32 and tape reel 33 taken out, and the welding boss 30 protruding inside the cassette half and the outer peripheral edge of the upper flange 34 of the tape reel 33 are made to avoid contact. , the distance between the two welding bosses 30 is relatively large. For this reason, although leaf springs 32 of different shapes are shown in FIGS. 11 and 12, both of these leaf springs 32 with large pitches of welding bosses 30 are wasteful in terms of the material used for the leaf springs. 32 has the disadvantage of high material costs. Further, if the pitch of the welding boss 30 is large as described above, a window for checking the remaining amount of magnetic tape cannot be formed in the welding boss 30 portion, so the shape of this window is restricted.

[Problem that the invention attempts to solve]

In this way, in conventional magnetic tape cassettes, when trying to avoid contact between the protrusion that protrudes inward from the lower half of the cassette and the lower flange of the tape reel using the guide groove of the centering mechanism, the external shape of the tape cassette becomes larger. There was a problem with this.

In addition, the welding boss that attaches the leaf spring for holding down the tape reel protrudes inside the upper half of the cassette, and if the welding boss pitch is increased to avoid contact between this welding boss and the upper flange of the tape reel, the leaf spring will A problem has arisen in that the shape of the leaf spring is wasteful in terms of material removal, and the cost of the material for the leaf spring increases. Further, when the welding boss pitch is increased in this way, the shape of the window for checking the remaining amount of magnetic tape is restricted.

Therefore, the present invention was proposed in order to solve these conventional problems, and it is possible to attach a magnetic tape to the inside of the cassette half without enlarging the external shape of the magnetic tape cassette or expanding the welding boss pitch. It is possible to prevent the protruding parts and welding bosses, which are protruding members, from coming into contact with the flange part of the tape reel, and it is possible to reduce the material cost of the reel holding plate spring, and it is also possible to prevent It is an object of the present invention to provide a magnetic tape cassette whose window shape is not limited.

[Means for solving problems]

In order to achieve this object, the magnetic tape cassette of the present invention is characterized in that a step is provided on the outer surface side of the outer peripheral edge of the flange of the tape reel, and the outer peripheral edge of the flange is made thinner.

[Effect]

Therefore, according to the present invention, by providing a relief for the protruding member protruding inwardly of the cassette half on the outer peripheral edge of the flange of the tape reel, the pitch of the welding boss can be reduced without increasing the size of the tape cassette. Contact between the outer peripheral edge of the flange and this protruding member can be prevented without expanding. Moreover, this makes it possible to reduce the cost of the reel presser plate spring, and to provide flexibility in the shape of the window for checking the remaining amount of magnetic tape.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a sectional view of a magnetic tape cassette showing an embodiment of the present invention.

In this figure 1, upper half 1 and lower half 2
A pair of tape reels 4 used for feeding or winding are arranged at a predetermined interval within a cassette half 3 consisting of. A magnetic tape 5 is wound around these tape reels 4, and an upper flange 6 and a lower flange 7 are provided for holding the magnetic tape 5 and guiding the winding. Also,
A video tape recorder (hereinafter referred to as
A reel stand of a VTR (referred to as a VTR) is fitted therein, and when the reel stand is rotated by a motor within the VTR, the tape reel 4 is rotated and the magnetic tape 5 is fed out or wound.

Further, a guide groove 9 is formed in the center of the bottom surface of the lower hearth 2 in the cassette loading direction to fit with the centering guide of the cassette holder described above. Moreover, by providing this guide groove 9, a protrusion 10 is formed as a convex part that protrudes inward of the lower half 2. This protrusion 10
Since they are formed corresponding to the guide groove 9 that fits into the centering guide, they are arranged between the pair of tape reels 4 in a direction perpendicular to the line connecting the centers of the pair of tape reels 4. It becomes.

Further, a reel presser plate spring 12 is attached to the inner side of the center portion of the upper half 1 by a welding boss 11, and the upper center of the tape reel 4 is pressed by this reel presser plate spring 12.
Further, the welding boss 11 to which the leaf spring 12 is attached projects inside the upper half 1.

Incidentally, a step 13 is provided on the outer surface side of the outer circumferential edge of the lower flange 7 of the tape reel 4, so that the outer circumferential edge of the lower flange 7 is thin. The depth of this step 13 is such that the protrusion 10 formed by the guide groove 9 and the outer peripheral edge of the lower flange 7 do not come into contact with each other. FIG. 2 shows an enlarged view of the outer peripheral edge of the lower flange 7 and the protruding portion 10, and the width l ₁ of the thin wall portion 14 due to the step 13 is 8 mm.
It is formed to a certain extent.

In this way, by providing the thin wall portion 14 on the outer peripheral edge that is placed on the protruding portion 10 of the lower flange 7 so as to interfere as shown in FIGS. 1 and 2, the distance between the tape reel axes is reduced. To prevent contact between the protrusion 10 and the outer peripheral edge of the lower flange 7 without enlarging the reel pitch, which is the distance between the lower half 2 and the lower flange 7, and without increasing the size of the tape cassette. You will be able to do this. Also,
By making the guide groove 9 deep, the centering guide provided on the cassette holder and the guide groove 9 can be fitted well, and a small tape cassette can be loaded at the center of the cassette holder. become able to. Here, since the width l ₁ of the thin portion 14 is as small as about 8 mm, the lower flange 7 does not suffer from surface runout or warpage.

Incidentally, a step 15 is similarly formed on the outer surface side of the outer peripheral edge of the upper flange 6 of the tape reel 4, and the outer peripheral edge of the upper flange 6 is thin. The depth of this step 15 is such that the welding boss 11 as a convex portion does not come into contact with the outer peripheral edge of the upper flange. FIG. 3 shows an enlarged view of the outer peripheral edge of the upper flange 6 and the welding boss 11, and the width l ₂ of the thinned portion 16 due to the step 15 is about 5 mm.

As described above, by providing the thin wall portion 16 on the outer peripheral edge of the upper flange 6 placed so as to interfere with the welding boss 11 as shown in FIG. 3, the welding boss 11
It is possible to prevent the welding bosses from coming into contact with the outer peripheral edge of the upper flange 6, and the welding boss pitch, which is the interval between the welding bosses 11, can be narrowed as shown in FIG. Therefore, the reel presser plate spring 12 attached by the welding boss 11 can be miniaturized, and the plate spring 12 can be shaped in such a way that there is no waste in terms of the material used for the plate spring. As a result, leaf spring 1
2 material costs can be lowered. In addition, by narrowing the welding boss pitch,
The shape of the window 17 for checking the remaining amount of magnetic tape is no longer limited, and the width w of the window 17 can be increased. Here, since the width l ₂ of the thin portion 16 is as small as about 5 mm, the upper flange 6 does not run out or warp.

[Effect of idea]

As explained above, according to the present invention, by forming a step and providing a thin wall part on the outer surface side of the outer peripheral edge of the flange of the tape reel, the outer peripheral edge of the flange can be removed without increasing the size of the tape cassette or expanding the welding boss pitch. This can prevent the guide groove, which is a protruding member protruding inside the cassette half, from coming into contact with the protrusion or welding boss.

Therefore, the guide groove can be made deeper without increasing the size of the tape cassette. Further, by making the guide groove deeper, the centering guide of the cassette holder can be fitted well into the guide groove, and a small tape cassette can be loaded at the center of the cassette holder. Therefore, by applying the present invention to magnetic tape cassettes of different sizes with different recording times, it becomes possible to easily record and reproduce data on these tape cassettes using the same VTR.

In addition, since the welding boss pitch can be narrowed,
The reel presser plate spring attached by this welding boss can be downsized. In addition, the shape of the leaf spring can be made efficient in terms of the material used, and the cost of the leaf spring can be reduced. Furthermore, since the welding boss pitch becomes narrower, the shape of the window for checking the remaining amount of magnetic tape is no longer limited.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a magnetic tape cassette which is an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the lower flange and guide groove of the tape reel of the tape cassette, and FIG. 3 is a cross-sectional view of the tape cassette. A sectional view showing the main parts of the upper flange of the tape reel and the welded boss part for the reel presser plate spring,
FIG. 4 is a plan view showing the upper flange and reel press plate spring portion of the tape cassette taken out;
Fig. 5 is a bottom view showing the guide groove formed on the bottom of the tape cassette, Fig. 6 is a schematic sectional view showing the cassette holder loaded with the tape cassette, and Figs. 7 and 8 are the conventional magnetic tape. 9 is a perspective view showing the external shape of the tape cassette; FIG. 10 is a sectional view schematically showing a conventional magnetic tape cassette; FIGS. 11 and 12 are plan views showing the reel presser plate spring and tape reel of a conventional magnetic tape cassette. 1... Upper half, 2... Lower half, 3... Cassette half, 4... Tape reel, 6... Upper flange, 7... Lower flange, 9... Guide groove, 10
...Protrusion, 11... Welding boss, 12... Reel press plate spring, 13, 15... Step, 14, 16...
...thin part, 17...window.

Claims (1)

[Claims for Utility Model Registration] In a magnetic tape cassette in which a pair of tape reels on which magnetic tape is wound are rotatably arranged in a cassette half, the pair of tape reels on the inner surface of the cassette half are arranged between the pair of tape reels on the inner surface of the cassette half. The tape reel has a convex portion arranged in a direction perpendicular to a line connecting the centers of the tape reel, and the tape reel is placed such that its outer peripheral edge interferes with the convex portion, and at least the outer peripheral edge of the flange of the tape reel is A magnetic tape cassette characterized in that a step is provided at a portion interfering with the convex portion to give it a thin shape.