JPH0756743B2 - Tape cassette - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an optimum one for a video tape recorder, for example.

[Outline of Invention]

The present invention relates to a tape cassette for a video tape recorder or the like, in which a reel is rotatably housed in a cassette housing composed of upper and lower halves, and the reel is pressed and urged toward a lower half by a spring. When the reel is driven to rotate, the line of action of the resultant force obtained by synthesizing the elastic force of the spring applied to the reel stand is configured so as to always coincide with the center line of the reel stand, and the reel is cored during rotation. This is to prevent shake and rattling.

[Conventional technology]

An example of an earlier application filed earlier by the applicant of the present invention (Actual Development Sho 61-2003
The tape cassette for a video tape recorder described in No. 75) will be described with reference to FIG.

In the tape cassette of this prior application, a pair of left and right reels 2 around which a magnetic tape 1 is wound are rotatably accommodated in a cassette housing 5 composed of upper and lower halves 3 and 4, and a pair of left and right reel retainers 6 is placed on the upper half. 3 are mounted movably up and down in a pair of left and right through holes 7 provided in the upper and lower reels 6 and the upper half 3
The reel retainer 6 is pressed downward by the spring 8 interposed between the metal plate 10 and the hemispherical projection 6a provided at the lower center of the reel retainer 6 and horizontally fixed to the upper center of the hub 9 of the reel 2. Is pressed from above to bias the reel 2 against the upper surface 4a of the lower half 4. An annular rib 12 concentrically provided on the lower surface of the lower flange 11 of the reel 2 is loosely fitted in a pair of left and right reel stand insertion holes 13 provided in the lower half 4 to allow the reel 2 in the cassette housing 5 to be inserted.
Is roughly positioned.

By the way, as heretofore known, when this type of tape cassette is mounted in a video tape recorder for use, a pair of left and right reel stands 14 relatively inserted from below into a pair of left and right reel stand insertion holes 13 are used. The reel shaft engaging hole 16 provided at the lower center of the hub 9 of the reel 2 is engaged with the outer periphery of the central reel shaft 15, and the annular rib 12 is provided on the upper surface 17a of the reel base flange 17 at the lower end of the reel shaft 15. At this time, the lower flange 11 of the reel 2 is levitated above the upper surface 4a of the lower half 4, and the compression repulsive force of the spring 8 at that time strongly presses the reel 2 downwardly, so that the annular rib 12 is reeled. The base flange 17 is pressed and fixed on the upper surface 17a. When the tape cassette is used, the cassette housing 5 is positioned at a predetermined position in the horizontal direction and the vertical direction by a cassette positioning member (not shown), and the reel is in a state unrelated to the positioning of the cassette housing 5. The center line P ₁ of ₂ is positioned on the center line P ₂ of the reel stand 14.

[Problems to be solved by the invention]

In the tape cassette of the prior application, the reel retainer 6 and the spring 8
Is attached to the upper half 3 side of the cassette housing 5, so that the position of the center line P ₃ of the reel retainer 6 with respect to the cassette housing 5 is always constant and immovable. On the other hand, when the tape cassette is used, the center line P ₁ of the reel 2 is the center line of the reel stand 14 regardless of the positioning of the cassette housing 5.
Since it is positioned on P ₂ , the position of the reel 2 in the cassette housing 5 in the horizontal direction (direction perpendicular to the center line P _{1 of the} reel 2) easily changes, and the center line P _{1 of the} reel 2 Was likely to cause a positional deviation X with respect to the center line P ₃ of the reel presser 6. When this displacement X occurs, the projection 6a of the reel retainer 6 that presses the metal plate 10 of the reel 2 from above shifts from the center line P _{1 of the} reel 2, and the spring 8 pushes the reel downward. The center of the pressure F ₁ cannot be correctly acted on the center line P ₁ of the reel 2. As a result, the entire circumference of the annular rib 12 of the reel 2 is covered with the upper surface 17 of the reel base flange 17.
When the reel base 14 cannot be stably fixed by being pressed evenly on the a, the core of the reel 2 may run out of the reel base 14 when the reel 2 is rotationally driven, and rattling may occur. The running of the tape 1 was likely to be extremely unstable.

According to the present invention, when the tape cassette is used, the center line of the reel is positioned on the center line of the reel stand regardless of the positioning of the cassette housing. Provided is a tape cassette in which the center of the downward pressing force of the spring by the spring can always be made to act correctly on the center line of the reel stand even if it occurs.

[Means for solving problems]

The present invention, in the above-mentioned tape cassette, has an annular recess formed in the central portion of the reel, and a cylindrical portion fitted to the annular recess on the side portion thereof, and at the center of the top portion thereof. It consists of a reel cap having a central projection that is pressed against the upper half, and a compression coil spring that is interposed between the top of the reel cap and the bottom of the annular recess. The reel cap expands and contracts in a gap formed by the one side wall and the inner peripheral surface of the cylindrical portion of the reel cap. As the reel cap expands and contracts, the outer wall of the cylindrical portion is formed on the other side wall of the annular recess. The tape cassette was constructed so that the surface was guided and reciprocated.

[Work]

The present invention intends to change the way of thinking that the reel cap and the spring are attached not to the upper half side of the cassette housing but to the reel side. As a result, even if the position of the reel changes in the horizontal direction in the cassette housing, the reel cap and the spring are moved in the horizontal direction together with the reel so that the reel cap and the spring are displaced from the center line of the reel. I was able to make sure nothing happened.

Therefore, it is possible to provide a tape cassette in which the center of the downward pressing force of the reel by the spring can always be made to act correctly on the center line of the reel regardless of the change in the horizontal position of the reel in the cassette housing. .

〔Example〕

An embodiment in which the present invention is applied to a tape cassette for a video tape recorder will be described below with reference to FIGS. 1A and 2.

First, a pair of left and right reels 24, which are rotatably accommodated in a cassette housing 23 composed of upper and lower halves 21 and 22 made of synthetic resin, are made of synthetic resin, and a magnetic tape is provided on the outer circumference. A hub 26 around which 25 is wound, and upper and lower flanges 27 and 28 provided on both upper and lower ends of the hub 26 are configured. The lower flange 28 is integrally formed on the outer periphery of the lower end of the hub 26, and the upper flange 27 is formed on the outer periphery of the upper end of the hub 26 with a plurality of dowel holes 30 provided in the peripheral edge 29a of the circular hole 29 in the center. The dowel 31 is fitted to the hub 31 and is concentrically and integrally fixed to the hub 26 by welding the dowel 31. Further, a reel shaft engaging hole 32 having an open lower end is provided in the center of the hub 26, and a pair of left and right reels in which an annular rib 33 integrally concentrically formed on the lower surface of the lower flange 28 is provided on the lower half 22. It is loosely fitted in the table insertion hole 34.

Next, a reel cap 36 that is vertically movable along the center line P ₁ of the reel 24 is attached to the upper center of the reel 24. The reel cap 36 is made of synthetic resin, has a cylindrical portion 36a on its side, and has a hemispherical central projection 37 at the center of its closed top.
Are integrally formed, and three outer peripheral projections 38 are integrally formed on the outer periphery of the lower end at equal intervals. On the other hand, a ring-shaped recess 39, which coincides with the circular hole 29 of the upper flange 27, is concentrically provided in the center upper portion of the hub 26 of the reel 24, and the side wall 39b on the outer side of the ring-shaped recess 39 has an upper side. Three crank-shaped holes 40 cut from the peripheral edge 29a of the circular hole 29 of the flange 27 are provided at equal intervals. Therefore, the three outer peripheral projections 38 are moved into the three crank-shaped holes 40 in the crank shape shown by the arrow a in FIG.
It is attached by inserting it from the upper circular hole 29 into the annular recess 39. By this attachment, the central protrusion 37 of the reel cap 36
Is located on the center line P ₁ of the reel 24, and the reel cap 36 is configured to be movable up and down along the center line P ₁ in the annular recess 39.

Next, a compression coil spring 42 is interposed between the top portion of the reel cap 36 and the bottom portion of the annular recess 39, the inner side wall 39a of the annular recess 39 and the reel cap 36.
Of the annular cross section formed by the inner peripheral surface of the cylindrical portion 36a of
The coil spring 42 is inserted in the coil 4 so that the center line thereof always coincides with the center line P _{1 of the} reel. At the time of actual assembly, the spring 42 is first inserted into the annular recess 39, and then the reel cap 36 is inserted against the spring 42 into the annular recess 39.

By the way, before the reel 24 is assembled into the cassette housing 23, the reel cap 36 pressed upward by the spring 42 is used.
The three outer peripheral projections 38 are the peripheral edge 29 of the circular hole 29 of the upper flange 27.
The reel cap 36 is abutted against the lower surface of a so as to prevent the reel cap 36 from coming off upward. However, in this state, the reel cap 36 can be pulled out from the reel 24 in the reverse crank shape shown by the arrow b which is the opposite direction of the arrow a in FIG.

On the other hand, as shown in FIG. 1B, when the reel 24 is assembled in the cassette housing 23, the reel cap 36 is slightly pushed down against the spring 42 by the upper half 21, and the three outer peripheral projections are formed. 38 sinks deeply into the three crank shaped holes 40. As a result, the reel cap 36 is moved from the reel 24 to the arrow b.
It becomes impossible to extract in the reverse crank shape shown in
The reel cap 36 is rotated together with the reel 24.

Then, the non-use state of the tape cassette configured as described above is shown in FIG. 1B, and the compression repulsion force of the spring 42 (however, the compression repulsion force in this non-use state is relatively weak). The reel cap 36 is pressed upward, the central projection 37 thereof is pressed against the lower surface 21a of the upper half 21, and the reel 24 is pressed downward, and the lower flange 28 thereof is pressed onto the upper surface 22a of the lower half 22. Being energized. Actually, the central projection 37 of the reel cap 36 is pressed against the lower surfaces of the pair of left and right metal plates 46 welded by the plurality of dowels 45 on the lower surface 21a of the upper half 21.

In this unused state, the central protrusion 37 of the reel cap 36 is pressed by the upper half 21 on the center line P _{1 of the} reel 24, and the elastic force of the spring 42 acting on the upper surface 22a of the lower half 22 is combined. The resultant resultant force line F ₂ is also on the center line P ₁ of the reel 24.

Next, the usage state of the tape cassette configured as described above is shown in FIG. 1A. When this tape cassette is mounted in the video tape recorder, it is inserted into the pair of left and right reel stand insertion holes 34 as in the conventional case. The reel is mounted on the outer circumference of the reel shaft 15 at the center of the pair of left and right reel stands 14 that are relatively inserted from below.
The reel shaft engaging hole 32 of the hub 26 of 24 is engaged, and the annular rib 33 is placed on the upper surface 17a of the reel base flange 17 at the lower end of the reel shaft 15, and at this time, the reel 24 lower flange 27 is lowered. While being floated above the upper surface 22a of the half 22, the reel 24 is strongly pressed downward by the compressive repulsive force of the spring 42 at that time, and the annular rib 33 causes the upper surface 17a of the reel stand flange 17 to move.
It is pressed and fixed on top. And when using this tape cassette, the positioning of the cassette housing 23 and the center line P ₁ of the reel 24 in unrelated state is a state where the center line P ₂ matches the reel base 14.

However, at this time, the reel cap 36 and the spring 42 are
Since it is mounted on the 24 side, when the position of the reel 24 changes in the horizontal direction (direction perpendicular to the center line P _{1 of the} reel 24) in the cassette housing 23, the reel cap 36 and the spring 42 also change. , Move with reel 24. The relationship described above, that is, the central protrusion 37 of the reel cap 36 is always on the center line P _{1 of the} reel 24, and the center line of the coil spring 42 is always the same as the center line P ₁ , is completely different. Absent. Therefore, regardless of the change in the horizontal position of the reel 24 in the cassette housing 23, the center of the downward reel pressing force F ₂ due to the spring 42 is always set to the center of the reel 24, just as when not in use as described above. Correct action on the center line P ₁ (the direction of the reel pressing force F ₂ is parallel to the center line P ₁ and the center of the reel pressing force F ₂ is located on the center line P ₁ ) . As a result, the entire circumference of the annular rib 33 of the reel 24 is evenly pressed on the upper surface 17a of the reel base flange 17, and the reel 24
Can be pressed and fixed on the reel stand 14 extremely stably. When the reel base 14 is driven to rotate, the reel 24 does not cause runout or rattling with respect to the reel base 14, and the reel 24 can always be rotated extremely stably, and the magnetic tape 25 Can always be driven extremely stably.

In addition, according to the tape cassette configured as described above,
As shown in FIG. 1B, the reel cap 36 is inserted into the annular recess 39 provided in the central upper portion of the reel 24 so that the reel 24 and the reel cap 36 overlap in the height direction.
Since H ₁ is set, the height H _{2 of the} entire cassette housing 23 can be reduced.

Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments and various effective modifications can be made based on the technical idea of the present invention.

Further, the present invention is not limited to tape cassettes for video tape recorders, but can be applied to various tape cassettes applied to various recording / reproducing devices.

〔The invention's effect〕

According to the present invention, the center of the downward pressing force of the spring by the spring can always be made to act correctly on the center line of the reel regardless of the change in the horizontal position of the reel in the cassette housing. It can be pressed and fixed very stably on top. Therefore, when the reel is driven to rotate by the reel stand, there is no occurrence of runout or rattling of the reel with respect to the reel stand, the reel can always be stably rotated, and the tape running can be remarkably stabilized. .

[Brief description of drawings]

1A to 2 show an embodiment of the present invention, wherein FIG. 1A is a sectional view of a main part in a used state, and FIG. 1B is a sectional view of a main part in a non-used state. FIG. 2 is an exploded perspective view of a main part. FIG. 3 is a sectional view of the prior application example. In the reference numerals used in the drawings, 21 …… upper half 22 …… lower half 23 …… cassette housing 24 …… reel 36 …… reel cap 36a …… cylindrical portion 37 …… center protrusion 39 …… annular recess 39a …… Inner side wall (one side wall) 39b …… Outer side wall (other side wall) 42 …… Compression coil spring 44 …… Gap P ₁ …… Reel center line.

Claims (1)

[Claims] 1. A tape cassette in which a reel is rotatably housed in a cassette housing composed of upper and lower halves, and the reel is pressed and urged toward a lower half by a spring, which is formed in a central portion of the reel. An annular recess, a reel cap having a cylindrical portion fitted to the annular recess on the side thereof, and a central protrusion pressed on the upper half at the center of the top thereof, and the reel cap. And a compression coil spring interposed between the top of the ring-shaped recess and the bottom of the ring-shaped recess.
The reel cap expands and contracts in a gap formed by the inner peripheral surface of the cylindrical portion, and as the reel cap expands and contracts, the outer peripheral surface of the cylindrical portion is guided to the other side wall of the annular recess. Reciprocating tape cassette.