JP3263865B2 - Tape cassette - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cassette tape for audio, for example, and more particularly to a cassette tape provided with a liner sheet.

[0002]

2. Description of the Related Art A tape cassette 101 in which a pair of hubs around which a magnetic tape is wound is housed rotatably as shown in FIG. Liner sheet 10 above and below
4, 105 are inserted. This kind of liner sheet 1
The sheets 04 and 105 are formed by pressing a sheet having a large lubricating effect and having excellent durability, such as silicon-impregnated paper, graphite, and polytetrafluoroethylene, into a predetermined size and shape.

In this example, the liner sheets 104, 1
Reference numeral 05 is substantially the same as the cassette width in the front-rear direction of the cassette into which the magnetic head is inserted. The liner sheets 104 and 105 are respectively provided at a portion between the magnetic tape winding portion 103a of the hub 103 and the magnetic tape 102 and a central portion of the magnetic tape 102 when the magnetic tape 102 is wound around the hub 103 at the maximum. An inwardly projecting convex portion 106 is provided.

[0004] These convex portions 106 have upper and lower halves 107,
The distance between the hub 108 and the hub 103 and the magnetic tape 102, that is, the internal clearance between them, is reduced, so that the hub 10 is moved when the magnetic tape 102 is running.
3 to prevent backlash and disturbance of winding of the magnetic tape 102. Therefore, when the magnetic tape 102 travels, the hub 103 rotates while being guided by the protrusion 106, and the end face of the magnetic tape 102 is wound around the hub 103 while being guided by the protrusion 106.

[0005]

When the area of the projections 106 provided on the liner sheets 104 and 105 is large, the sliding resistance between the projections 106 and the magnetic tape 102 increases, and the magnetic tape 102 runs stably. May be damaged. Also, the protrusions 10 of the magnetic tape 102
The end face in contact with No. 6 is damaged, causing breakage or bending. Further, it becomes difficult to keep the above-mentioned internal clearance constant due to warpage, deformation, and the like of the liner sheets 104 and 105, and the running of the magnetic tape 102 becomes unstable.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a highly reliable cassette tape capable of winding the tape without damaging the tape without damaging the tape. .

[0007]

SUMMARY OF THE INVENTION A tape cassette according to the present invention proposed to achieve the above object is provided by:
A pair of hubs around which a magnetic tape is wound, and an annular hub receiver which rotatably accommodates the hubs and which protrudes inward from an opening peripheral portion of the hub fitting hole on an inner surface facing the hub. The upper and lower halves of the cassette body are provided with the upper and lower halves, and the upper and lower halves are interposed between the hub receiving portions and the hubs. A pair of liner sheets each having a curved end directed inward of the cassette body and having a circular hole in the flat portion, wherein the outer diameter of the magnetic tape winding portion of the hub is A; When the outer diameter of the receiving portion is B and the size of the flat portion of the liner sheet is C, the relationship A ≦ B <C is satisfied.

Preferably, the clearance between the opposing upper and lower half hub receiving portions and the hub around which the magnetic tape is wound is in the range of 0.2 to 0.35 mm, and is disposed within the clearance. 25-75μ as liner sheet
m is used.

Further, it is desirable that the amount of bulging of the curved portion formed at the end of the liner sheet is smaller than the protrusion size of the hub receiving portion. Further, the liner sheet is desirably made of slippery polyethylene terephthalate.

[0010]

In the tape cassette according to the present invention, an annular hub receiving portion is provided on the inner surface of the upper and lower halves opposed to the hub rotatably disposed in the cassette main body so as to protrude inward of the cassette main body. Therefore, the distance between the hub receiving portion and the end face of the hub, that is, the internal clearance between the facing portions becomes small, and the hub is rotated in a state where the hub is held at the center of the cassette by the hub receiving portion during tape running, and the magnetic tape Stable running is ensured.

In the liner sheet, at least a portion supported by the hub receiving portion is a flat portion, so that the hub is supported by the flat portion of the liner sheet,
It rotates smoothly without undulations, and winds the magnetic tape around the hub without any disturbance.

The curved portion provided at the end of the liner sheet contacts the end face in the width direction of the magnetic tape wound around the hub, thereby adjusting the winding state of the magnetic tape.

Further, since the liner sheet is formed of slippery polyethylene terephthalate, the sliding resistance against the magnetic tape becomes small,
The running stability of the magnetic tape is improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an audio tape cassette will be described below. As shown in FIG. 1, a cassette tape according to the present invention has a pair of hubs 2 around which a magnetic tape 1 is wound (one hub is not shown).
And upper and lower halves 3, which rotatably store these hubs 2,
4 and a liner sheet 6, 7 inserted in the cassette body 5 above and below the hub 2 in the cassette body 5.

The hub 2 provided in the cassette body 5
A cylindrical magnetic tape winding portion 8 and upper and lower halves 3, 4
Hub fitting holes 9 and 10 each having a circular shape and opened in
And projecting portions 11 and 12 facing the front. The magnetic tape winding portion 8 has a function of winding the magnetic tape 1 around its peripheral surface, and the protruding portions 11 and 12 have a function of restricting rotation of the hub 2 facing the hub fitting holes 9 and 10. Have.

Each of the upper half 3 and the lower half 4 constituting the cassette main body 5 is formed by injection molding a resin to a size large enough to rotatably accommodate the pair of hubs 2 around which the magnetic tape 1 is wound. It is formed integrally. The upper half 3 and the lower half 4 are butt-engaged with their openings facing each other to form a cassette body 5.

The upper half 3 and the lower half 4 are provided with hub receiving portions 13 and 14 for guiding the hub 2 to enable stable rotation. These hub receiving parts 1
Reference numerals 3 and 14 are formed on the inner surfaces 3 a and 4 a of the hub 2 facing the magnetic tape winding portion 8 as annular protrusions protruding inward of the cassette body 5. The hub receiving portion 14 provided in the lower half 4 will be described with reference to FIG. 2. The hub receiving portion 14 is a hub fitting hole 1 opened in the lower half 4.
0 is formed as an annular protrusion protruding inward of the cassette main body 5 so as to reduce the distance between the hub 2 and the magnetic tape winding portion 8 so as to reduce the facing distance. Similarly, although not shown, a hub receiving portion 13 is also formed as an annular projection on the peripheral edge of the opening of the hub fitting hole 9 of the upper half 3. Therefore, the hub 2 has upper and lower halves 3,
The cassette receiver 5 is rotated by the hub receiving portions 13 and 14 provided in the upper portion 4 in a state where the movement of the cassette body 5 in the vertical direction, which is the thickness direction, is restricted, and rattling during rotation is prevented.

The liner sheets 6, 7 serve to prevent the magnetic tape 1 from being disturbed and to rotate the hub 2 in a stable state. The liner sheets 6, 7 have hub receiving portions 13, 14 of the upper and lower halves 3, 4, and the hub 2 Are disposed so as to be interposed therebetween. These liner sheets 6 and 7 are formed by, for example, pressing a sheet made of polyethylene terephthalate having excellent lubricity in order to reduce sliding resistance to the magnetic tape 1 and the hub 2. In order to give the polyethylene terephthalate lubricity, for example, a sliding material such as silicon is applied to the sliding surface side.

As shown in FIG. 3, one of the liner sheets 6, 7 has a substantially rectangular planar shape, and faces the hub fitting holes 9, 10 formed in the upper and lower halves 3, 4, respectively. At positions, circular holes 15 and 16 having substantially the same diameter as the hub fitting holes 9 and 10 are provided. In addition, the liner sheets 6 and 7 have a flat portion at the center in the front-rear direction of the cassette body 5 indicated by an arrow A in FIG. 2 and have an end in the front-rear direction curved toward the inside of the cassette body 5. Curved portion. That is, the liner sheets 6 and 7 are flat portions 17 having a flat central portion facing the hub 2, and come into contact with the end surface in the width direction of the magnetic tape 1 wound around the magnetic tape winding portion 8. The portion is a curved portion 18 having a semicircular shape.

The flat portions 17 provided on the liner sheets 6, 7 are provided so as to be located between the hub receiving portions 13, 14 and the magnetic tape winding portion 8, and the flat portions 17 cause the hub 2 to undulate. It plays the role of rotating smoothly so that there is no. On the other hand, the curved portions 18 provided at the ends of the liner sheets 6 and 7 come into contact with the end surface in the width direction of the magnetic tape 1 that is gradually wound around the magnetic tape winding portion 8 to wind the magnetic tape 1. It regulates the appearance and regulates the winding state of the magnetic tape 1 around the magnetic tape winding section 8.
Therefore, the liner sheets 6 and 7 are required to have a hardness such that the tip of the curved portion 18 does not contact the tape edge and damage the tape when the magnetic tape 1 is running, and to be able to maintain the curved shape for a long time. . In order to satisfy these, the thickness of the liner sheets 6 and 7 should be 25 to 75.
μm is desirable.

In the cassette tape constructed as described above, the outer diameter of the magnetic tape winding section 8 is A, and the hub receiving section 1 is
Assuming that the outer diameters of the members 3 and 14 are B and the size of the flat portions 17 of the liner sheets 6 and 7 are C, the relationship A ≦ B <C is satisfied. Referring to FIG. 4, the outer diameter B of the hub receiving portions 13 and 14 is the same as or larger than the outer diameter A of the magnetic tape winding portion 8, and the liner sheets 6 and 7 have a larger diameter. Dimension C of the flat part 17
It has been made smaller.

As described above, if the outer diameter B of the hub receiving portions 13 and 14 is made larger than the outer diameter A of the magnetic tape winding portion 8, the hub 2 is reliably guided at the center of the cassette body 5. Therefore, stable rotation of the hub 2 can be ensured. Further, since the dimension C of the flat portion 17 of the liner sheets 6, 7 is made larger than the outer diameter dimension B of the hub receiving portions 13, 14, at least the hub receiving portion 1 is provided.
Since the flat surfaces 3 and 14 are flat surfaces, the flat surface allows the hub 2 to be smoothly rotated without undulation or the like.

The amount of bulging of the curved portion 18 formed at the end of the liner sheets 6 and 7 from the flat portion 17 is determined by the hub receiving portion for winding the magnetic tape 1 around the hub 2 without being disturbed. 13 and 14 are smaller than the protruding height E. Specifically, the bulging amount F of the curved portion 18 from the flat portion 17 is 0.1 mm to 1.6 mm, and more preferably 0.5 mm to 1.5 mm. On the other hand, the protrusion dimension E of the hub receiving portions 13 and 14 is 0.2 mm to 1.2 m.
m, more preferably 0.5 to 1.0 mm. Here, the “more preferable dimensions” are values when the thickness of the liner sheets 6 and 7 is about 40 μm. By defining the bulging amount of the curved portion 18 as described above, the curved portion 18 can freely move within the clearance in the process of winding the magnetic tape 1 around the hub 2. Accordingly, the followability of the curved portion 18 that regulates the tape is improved, and the magnetic tape 1 can be optimally held.

The dimension D of the flat portion 17 extending to the outer periphery of the hub receiving portions 13 and 14 of the liner sheets 6 and 7 and reaching the curved portion 18 at the end is determined by the elastic force of the curved portion 18. In order to allow the magnetic tape 1 to be wound around the hub 2, the thickness is set to 0.6 to 2.2 mm, more preferably 0.5 to 2.2 mm.
１．５1.5 mm. The reason why the dimension D of the flat portion 17 extending on the outer periphery of the hub receiving portions 13 and 14 is set in the above range is as follows.
This is because the elastic force applied to the curved portion 18 is the most optimal value that allows the magnetic tape 1 to be wound around the hub 2 without any disturbance.

Further, in the above-described cassette tape, hub receiving portions 13 and 14 of upper half 3 and lower half 4 are provided.
, The thickness of the upper and lower liner sheets 6, 7 and the sum of the thicknesses of the magnetic tape winding portions 8 of the hub 2 are larger than a value obtained by subtracting 0.3 mm from the thickness H of the cassette tape after assembling the upper and lower halves. The definition in such a range is based on the following points.

For example, in FIG. 4, when the thickness of the liner sheets 6 and 7 in the cassette tape after assembling the upper and lower halves is ignored, the hub receiving portions 1 of the upper and lower halves 3 and 4 are disregarded.
Opposition distance H1 between 3.14 (4.60-4.70mm)
From the height H2 of the magnetic tape winding portion 8 (4.35 to 4.4).
0mm), 0.35mm maximum, 0.2 minimum
0mm and the clearance is 0.20 ~ 0.35
mm. On the other hand, the thickness (0.
038 mm), the maximum is 0.274 mm, the minimum is 0.124 mm, and the clearance is 0.124 mm.
０．２0.274 mm. Therefore, the total sum of the above thicknesses is calculated as 0.3 mm obtained by rounding up a decimal point of 0.274 mm, which is the maximum value of the clearance in consideration of the thickness of the liner sheets 6 and 7, from the thickness H of the cassette tape after assembling the upper and lower halves. If the value is larger than the value obtained by pulling, the facing distance between the hub receiving portions 13 and 14 and the magnetic tape winding portion 8 is further reduced, and the hub 2 is stabilized by the guides of the hub receiving portions 13 and 14 without rattling. The magnetic tape 1 can be wound around the hub 2 without any turbulence.

Here, actually, a cassette tape is manufactured on the basis of the above conditions, and the loss torque and magnetic force when the bulging amount of the curved portion 18 of the liner sheets 6 and 7 and the size of the flat portion 17 are changed. The winding state of the tape 1 was examined. The loss torque was determined by reading the maximum friction torque when winding the entire length of the tape from the start of winding to the end of winding with no back tension, with the winding speed in the range of 400 to 600 rpm. The winding state of the magnetic tape 1 was visually determined. Table 1 shows the results.

[0028]

[Table 1] As can be seen from the results, when the flat portions 17 of the liner sheets 6 and 7 are made larger and the amount of protrusion of the curved portions 18 is made larger, the absolute value of the loss torque becomes larger and the variation becomes larger. When the magnetic tape 1 is wound around the hub 2 in this state, the magnetic tape 1 is disturbed, and the magnetic tape 1 is loosened or damaged.

[0029]

As described above, according to the present invention, an annular hub receiving portion is provided on the inner surfaces of the upper and lower halves opposed to the hub, the annular hub receiving portions projecting inward of the cassette body, and the central portion is flat and both end portions are provided. A liner sheet having a curved portion,
By inserting the hub between the hub receiving portion and the hub, and defining the outer diameter of the magnetic tape winding portion of these hubs, the outer diameter of the hub receiving portion, and the flat portion of the liner sheet, Without damaging or loosening the tape, the magnetic tape can be wound around the hub without turbulence so that the end faces are aligned. In addition, running durability can be greatly improved.

Further, since the curved portion is provided at the end of the liner sheet, the curved portion comes into contact with the end surface in the width direction of the magnetic tape wound around the hub, and the elastic force of the curved portion is provided. Thus, the winding state of the magnetic tape is properly adjusted, and the winding is possible.

Further, since the liner sheet is made of slippery polyethylene terephthalate, the sliding resistance against the magnetic tape is reduced, so that the magnetic tape can run stably and the running durability of the liner sheet and the magnetic tape can be improved. Performance can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a cassette tape according to the present invention.

FIG. 2 is a plan view of a lower half of the tape cassette.

FIG. 3 is a perspective view showing a liner sheet.

FIG. 4 is a sectional view of a main part of the cassette tape according to the present invention.

FIG. 5 is a sectional view showing a conventional cassette tape.

[Explanation of symbols]

1 magnetic tape, 2 hub, 3 upper half, 4
Lower half, 5 cassette body, 6,7 liner sheet, 8 magnetic tape winding section, 13,14 hub receiving section, 17 flat section, 18 curved section

Claims (4)

(57) [Claims] A pair of hubs around which a magnetic tape is wound;
A cassette body comprising upper and lower halves that rotatably house the hub and that has an annular hub receiving portion provided on the inner surface facing the hub and protruding inward from the peripheral edge of the opening of the hub fitting hole. When the upper and lower halves of the disposed interposed between each of the hub receiving portion and the hub, wherein the cassette ends in the longitudinal direction with the longitudinal direction central portion of the cassette body is a flat portion It is a curved towards the inside of the body and before
A pair of liner sheets each having a circular hole in the flat portion , wherein the outer diameter of the magnetic tape winding portion of the hub is A, the outer diameter of the hub receiving portion is B, and the size of the flat portion of the liner sheet. A cassette tape having a relationship of A ≦ B <C, where 2. The hub receiving portions of the upper and lower halves are opposed to each other.
Between the hub and the hub around which the magnetic tape is wound
The clearance should be in the range of 0.2 to 0.35 mm.
The liner sheet disposed in the
2. The tape cassette according to claim 1 , having a thickness of m . 3. A bulge amount from the flat portion of the curved portion formed in the end portion of the liner sheet cassette according to claim 1, wherein a smaller than the projecting dimension of the hub receiving portion tape. 4. The cassette tape according to claim 1 , wherein said liner sheet is made of slippery polyethylene terephthalate.