JPH06203524A - Tape cassette - Google Patents

Abstract

PURPOSE:To lay a protective sheet on a sheet laying base with high accuracy by thinning the thickness of a tape protective part of the protective sheet and thickening the thickness of a calking flange part. CONSTITUTION:The thickness T1 of the tape protective part 14a of the protective sheet 14 is thinned, and the thickness T3 of the calking flange part 14c is thickened. By this method, the tape protective part 14a is given elasticity, while rigidity of the flange part 14c is enhanced to prevent the occurrence of distortion, etc., of the flange part, so that a magnetic tape can securely be protected by absorbing impact, etc., on the magnetic tape by the elasticity of the tape protective part 14a. Then, since the protective sheet can easily and accurately be positioned to a calking pin 21, the protective sheet can easily be laid on the sheet laying base 16 with high accuracy. Furthermore, since the protective sheet can easily and accurately be positioned to the calking pin 21, automatic assembly is feasible, and hence the productivity can drastically be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape cassette, and more particularly to a tape cassette in which a synthetic resin protective sheet for protecting an edge of a magnetic tape is caulked in a cassette housing formed of synthetic resin.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS.
There is a tape cassette called a U-matic cassette (trade name of Sony Corporation) that uses a 1-inch wide magnetic tape for a video tape recorder.

This tape cassette comprises a cassette housing 3 composed of upper and lower halves 1 and 2 molded from a synthetic resin such as polyethylene, and a pair of left and right single-flange reels 4 rotatably housed in the cassette housing 3. A magnetic tape 6 having a width of 1 inch is wound around and housed in the tape 5.
The one flange reel 4 is integrally formed with the flange 4b only on the lower end side of the hub 4a, and the other one flange reel 5 is integrally formed with the flange 5b only on the upper end side of the hub 5a. Then, the pair of flanges 4b and 5b are overlapped with each other at the center position of the cassette housing 3 from above and below, thereby achieving both the downsizing of the cassette housing 3 and the upsizing of the winding diameter of the magnetic tape 6. Is.

At the center of the two half flange reels 4 and 5, the inner half 1a of the upper half 1 is integrally formed with a pair of left and right single flange reels 4 and 5 for controlling the amount of sliding, and the lower half 2 is formed. A pair of left and right reel stand insertion holes 8 are formed in the. Further, a transparent window cover 9 is provided on one end side of the upper half 1.
Is stuck. The magnetic tape 6 is guided and passed by a pair of tape guides 11 along a front opening 10 for pulling out the magnetic tape of the cassette housing 3, and an openable and closable lid 12 is attached to the front opening 10. ing. .

Next, in this tape cassette, the lower half inner surface 1a of the upper half 1 and the upper inner surface 2a of the lower half 2 which are the inner surfaces of the cassette housing 3 have the respective flanges 4b of the two-sided flange reels 4 and 5. 5b has a thickness of 0.1 when vacuum-molded with a synthetic resin sheet such as polypropylene or ultra-high-molecular-weight polyethylene having an excellent sliding effect at a position facing 5b.
Protective sheets 14 and 15 of about 0.2 mm are laid.

At this time, on the side of the one-sided flange reel 4, the one-sided flange reel 4 is provided on the inner surface 1a of the upper half 1.
A pair of sheet laying bases 16 each having a trapezoidal cross section and a substantially fan-shaped planar shape are integrally formed on both sides of the hub 4a, and the pair of protective sheets 14 are provided on the lower surfaces 16a of the pair of seat laying bases 16. Are laid horizontally. Also,
On the other one-flange reel 5 side, the inner surface 2 of the lower half 2
a, a sheet laying table 17 having a substantially trapezoidal cross section and a horseshoe-shaped plan is integrally formed on the outer periphery of the rib 5a of the one-flange reel 5.
The protective sheet 15 is horizontally laid on the upper surface 17 a of the sheet 7. The sheet laying stands 16 and 17 are formed by a large number of ribs 18.

Then, as shown in FIG. 8, in the non-use state, the lower edge 6b of the magnetic tape 6 wound around the outer periphery of the hub 5a of the other one-flange reel 5 is placed on the lower protective sheet 15. Configured to be placed.

Further, as shown in FIG. 10, the pair of upper protective sheets 14 laid on the lower surface 16a of the sheet laying table 16 of the upper half 1 is usually about 2 mm higher than the upper edge 6a of the magnetic tape 6. The height H is set to H and the upper edge 6a of the magnetic tape 6 does not come into contact with the pair of upper protective sheets 14 in a normal use state.

Then, the pair of upper protective sheets 14
As shown in FIG. 10, when this tape cassette is housed in the hard case 19 and transported, one of the one-sided flange reels 4 is tilted by vibration or the like, as shown by a chain line in FIG. At this time, the upper edge 6a of the magnetic tape 6 is brought into contact with them to prevent vibration of the one-flange reel 4 to a certain extent or more, and the upper edge 6a of the magnetic tape 6 directly contacts the inner surface 1a of the upper half 1. It has a function of protecting the magnetic tape 6 so as to prevent the contact and damage.

In FIG. 10, 19a is a hard case main body, 19b is a hard case cover, and 19c is a pair of left and right reel detents integrally formed on the hard case main body 19a.
When housed inside, the pair of reel detents 19a are inserted into the hubs 4a and 5a of the pair of single flange reels 4 and 5 through the pair of reel base insertion holes 8 to remove the pair of single flange reels 4 and 5. This is to prevent unexpected rotation due to vibration or the like.

Therefore, the height H of the pair of upper protective sheets 14 with respect to the upper edge 6a of the magnetic tape 6 shown in FIG.
Is too high or the parallelism is out of order, the amount of vibration of the one-flange reel 4 during transportation becomes large, and the collision force of the upper edge 6a of the magnetic tape 6 against the protective sheet 14 increases, and the upper edge 6a thereof increases. Is easily damaged. If the height H is too low or the parallelism is incorrect, the upper edge 6a of the magnetic tape 6 is constantly in contact with the pair of protective sheets 14 in a normal use state, and the upper edge 6a is damaged. easy. Therefore, the height H and the parallelism of the protective sheet 14 with respect to the upper edge 6a are very important.

By the way, conventionally, in this kind of tape cassette, one pair of protective sheets 14 is provided with four crimping pins 2 on both right and left sides of the sheet laying table 16 of the upper half 1.
It was clamped by 1. The other protective sheet 15 was adhered to the sheet laying table 17 of the lower half 2.

Therefore, a conventional crimping method for the protective sheet 14 will be described with reference to FIGS. 11 and 12. In addition,
10 and 12, the upper half 1 is shown upside down.

First, on the inner surface 1a of the upper half 1, on each of the left and right sides of the seat laying table 16, a pair of caulking pins 21 of a total of four small diameters are vertically integrally formed. Further, the protective sheet 14 is a vacuum formed sheet having a substantially trapezoidal cross-sectional shape, is formed on the tape protective portion 14a having a horizontal top portion, and has a franc portion 14c through the side wall portion 14b over the entire lower portion of the outer periphery thereof. Are integrally molded. Further, the pair of left and right caulking holes 22, which are a total of four through holes, are formed in the francy portion 14c.

Therefore, as shown in FIG. 12A, the flange portion 14c of the protective sheet 14 is provided with four caulking holes 22.
After inserting the four caulking pins 21 from above by the above and covering the sheet laying table 16 with the protective sheet 14, FIG.
(B), the four crimping pins 21 are pressed by heating these crimping pins 21 from above while heating them with a heating and pressurizing means such as an ultrasonic welding horn 23.
Protective sheet 14 by crimping while melting tip 21a of
The left and right pair of flange portions 14c on the inner surface 1a of the upper half 1
I was trying to stick to.

[0016]

[Problems to be Solved by the Invention] Conventionally, polypropylene or ultra-high molecular weight polyethylene having a thickness of 0.1 to 0.2 m is used.
Since the protective sheet 14 was vacuum formed using a synthetic resin sheet of about m, two steps of a vacuum forming step, an outer peripheral cut after the vacuum forming, and a step of punching the caulking hole 22 are required, resulting in high productivity. There was a problem that it was low and costly.

Further, the conventional protective sheet 14 vacuum-formed with a very thin synthetic resin sheet having a thickness of about 0.1 to 0.2 mm is apt to be distorted and the flange portion 14c is formed after the protective sheet is formed. Since the four caulking holes 22 must be drilled, it is difficult to obtain the positional accuracy of the four caulking holes 22. Therefore, when the protective sheet 14 is assembled, the four caulking holes 22 must be manually inserted into the four caulking pins 21 by the operator, which requires a large number of assembling steps and takes a long time for the assembling work. There was a problem.

Conventionally, in consideration of the distortion of the protective sheet 14, when the protective sheet 14 is assembled, the four caulking holes 2 are provided.
The diameters of these caulking holes 22 are formed to be larger than the diameters of the caulking pins 21 so that 2 can be easily inserted into the four caulking pins 21.

However, if the diameter difference of the caulking hole 22 with respect to the caulking pin 21 is too large, the positional displacement of the protective sheet 14 when the protective sheet 14 is placed on the sheet laying base 16 becomes large, and the protective sheet 14 shown in FIG. As shown in (C), a part of the flange portion 14c accidentally rides on the caulking pin 21, and the protective sheet 14 inclines unexpectedly, so that the protective sheet 14 is caulked at a later caulking operation of the caulking pin 21. The whole is crushed by the crumple and becomes a defective product, and the protection sheet 14 is lifted or parallelized with respect to the lower surface (the upper surface in FIG. 12) 16a which is the top of the sheet laying stand 16. Crazy was easy to occur. Further, since the flange portion 14c is thin, distortion or the like is likely to occur in the entire protective sheet 14 even when the crimping pin 21 is crimped.

If the protective sheet 14 rises or is displaced in parallelism with respect to the lower surface 16a of the sheet laying table 16, the height H of the protective sheet 14 relative to the upper edge 6a of the magnetic tape 6 shown in FIG. There is a problem in that the top edge 6a of the magnetic tape 6 is likely to be damaged due to the deviation.

The present invention has been made in order to solve the above problems, and a protective sheet can be laid on a sheet laying table with high precision. It is intended to provide a tape cassette.

[0022]

The tape cassette of the present invention for achieving the above object is at least one of a pair of reels for winding and storing a magnetic tape in a cassette housing formed of synthetic resin. One of them is configured as a single-flange reel, and a sheet laying table and a plurality of caulking pins arranged on the outside thereof are integrally formed on the inner surface of the cassette housing on the side opposite to the flange side of the single-flange reel. The tape protection part of the protective sheet that protects the edge of the magnetic tape fitted to the flange reel on the side opposite to the flange side is laid on the sheet laying table, and the flange part for caulking the protective sheet is provided. In the tape cassette, which is inserted into the plurality of crimping pins, melted and crimped, the protective sheet is injection-molded with a synthetic resin. , By reducing the thickness of the tape protection portion of the protective sheet, it is obtained by increasing the thickness of the flange portion for the caulking. At this time, forming a gap between the tape protection portion of the protective sheet and the sheet laying table,
It is preferable that a thick flange portion for caulking is formed on the entire circumference of the protective sheet, and an injection gate of synthetic resin is set on the flange portion.

[0023]

In the tape cassette of the present invention constructed as described above, the protective sheet is injection-molded with a synthetic resin, and the tape protective portion of the protective sheet is thin and the caulking flange portion is thick. Since the tape protector is made thicker, the tape protector can have elasticity, and the rigidity of the flange can be increased so that the flange is prevented from being distorted.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a tape cassette to which the present invention is applied will be described below with reference to FIGS. 7 to 7.
The same reference numerals are given to the same structural parts as those in FIG. 12, and duplicate description will be omitted.

In this embodiment, one protective sheet 14 laid on the inner surface 1a of the upper half 1 will be described, but the other protective sheet 15 laid on the inner surface 2a of the lower half 2 should be constructed in exactly the same manner. You can

First, as shown in FIGS. 1 and 2, the protective sheet 14 is injection-molded using a synthetic resin such as polypropylene or ultra-high molecular weight polyethylene having an excellent sliding effect.

In the protective sheet 14, the tape protective portion 14a and the side wall portion 14b both have a wall thickness T ₁ of 0.1 to 0.1.
The tape protector 1 has a thin thickness of about 0.2 mm.
4a has elasticity. On the other hand, the flange portion 14c
Is thick enough to have a thickness T ₃ of 0.2 mm or more, thereby increasing the rigidity of the flange portion 14c.

Simultaneously with the injection molding of the protective sheet 14, a pair of left and right caulking holes 22 are formed on the flange portion 14c, that is, a total of four caulking holes 22 are formed. The flange 14c
May be only on both the left and right sides of the side wall portion 14b so that a pair of left and right caulking holes 22 can be formed.
A flange portion 14c is integrally formed on the entire circumference of b.

At this time, as shown in FIG. 3A, the outer periphery of the tape protection portion 14a of the protection sheet 14 and the side wall portion 14b.
The thickness T of the root portion 14d and the tape protection portion 14a thereof
₁ is formed to have a thickness of about 0.1 to 0.2 mm, the wall thickness T ₂ of the side wall portion 14b is formed to be 0.2 mm or less, and the flange portion 14c is formed.
The thickness may be formed to be 0.2 mm or more so that the thickness gradually increases from the tape protection portion 14a to the flange portion 14c. Further, as shown in FIG. 3B, the wall thickness T ₃ of the side wall portion 14b and the flange portion 14c on the outer circumference of the tape protection portion 14a may be increased to 0.2 mm or more.

Next, as shown in FIGS. 4 to 6, during injection molding of the protective sheet 14 with synthetic resin, a molten resin 29 is injected into a cavity 28 formed between the upper and lower molding dies 26 and 27. It is injected from the gate 30 and molded,
At that time, by forming the injection gate 30 in the thick flange portion 14c of the protective sheet 14, the molten resin 29 can be injected into the cavity 28 at a low pressure in a short time. The molten resin 29 can be easily injected.

As a result, distortion or the like during injection molding of the protective sheet 14 is unlikely to occur, and the protective sheet 14 can be injection molded with high precision.

Next, the injection gate position will be described with reference to FIGS. 4 to 6, but the protective sheet 14 is shown upside down in the drawings. Further, the flange portion 14c of the protective sheet 14
Unlike the tape protection portion 14c, the magnetic tape 6 does not come into contact with the magnetic tape 6 at all, which facilitates gate processing after injection molding. The injection gate 30 has a lower surface 14c ₂ of the flange portion 14c as shown in FIG. As shown in FIG. 6, the outer peripheral surface 14c ₃ of the flange portion 14c is the upper surface 1 of the flange portion 14c.
It may be provided at any position of 4c ₁ .

Therefore, the degree of freedom of the gate area and the gate system is widened, and the die design is facilitated. However, as shown in FIG. 6, when forming the injection gate 30 on the upper surface 14c ₁ of the flange portion 14c, it is preferable to form the injection gate 30 in the recess 31 formed on the upper surface 14c ₁ .

As described above, the protective sheet 14 can be easily and accurately injection-molded, and the flange portion 1 can be formed.
Since the wall thickness of 4c is increased to increase the rigidity of the flange portion 14c, the flange portion 14a is not distorted and the flatness of the flange portion 14a can be ensured with high accuracy, and a plurality of applied portions can be provided. The dimensional relationship of the fastening holes 22 can also be set with high accuracy.

Therefore, as shown in FIG. 1B, the height dimension H ₁ of the tape protection portion 14a with the lower surface 14c ₁ of the flange portion 14c of the protection sheet 14 as a reference surface can be accurately adjusted to an arbitrary dimension. Can be set. Since the height dimension H ₁ can be easily controlled, the product inspection in the manufacturing process of the protective sheet 14 can be facilitated and the productivity can be improved.

By the way, the protective sheet 14 is inserted into the plurality of caulking pins 21 of the upper half 1 by the plurality of caulking holes 22 as shown in FIG. Then, put the protective sheet 14 on the sheet laying table 1
6 and then, as shown in FIG. 1B, the tips of the plurality of caulking pins 21 are melted and caulked by an ultrasonic welding horn or the like, and the protective sheet 14 is attached to the inner surface of the upper half 1. Stick to 1a.

At this time, the flange portion 14 of the protective sheet 14
Since the rigidity of c is high and the dimensional relationship of the plurality of caulking holes 22 is set with high accuracy, as shown in FIG.
Since the work of inserting the plurality of caulking holes 22 into the plurality of caulking pins 21 and positioning can be performed easily and with high accuracy, the work of laying the protective sheet 14 on the sheet laying table 16 is facilitated, In addition, it can be performed with high accuracy, especially the protective sheet 1
4. Automatic assembly of 4 is easy.

Further, as shown in FIG. 1B, the height dimension H ₁ of the tape protection portion 14a with the upper surface 14c ₁ of the flange portion 14c as a reference surface is set to the lower surface 16a of the sheet laying table 16.
It is possible to easily secure a gap 32 having a predetermined size between the tape protection portion 14a and the lower surface 16a of the sheet laying stand 16a by setting the height dimension H ₂ to be slightly larger than the height dimension H ₂ .

On the other hand, the tape protection portion 14 of the protection sheet 14
Since a is thin and has elasticity, the gap 3
If 2 can be secured, the tape protection portion 14a can have sufficient elasticity, and even if the magnetic tape 6 collides with the tape protection portion 14a due to a shock during transportation of the tape cassette, the Due to the high elasticity, the shock at that time can be absorbed and the magnetic tape 6 can be effectively protected.

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

[0041]

The tape cassette of the present invention constructed as described above has the following effects.

According to the first aspect of the present invention, since the protective sheet is injection-molded from synthetic resin, the protective sheet and the plurality of caulking holes can be formed in one step, and the productivity is high and the cost is low. In addition, the degree of freedom in designing the shape of the protective sheet is high.

According to a first aspect of the present invention, the tape protective portion of the protective sheet is thin and the caulking flange portion is thick,
In addition to giving elasticity to the tape protection part, the rigidity of the flange part was enhanced so that distortion etc. did not occur in the flange part, so the elasticity of the tape protection part absorbs the impact of the magnetic tape, etc. Although the tape can be reliably protected, the protection sheet can be easily and accurately positioned with respect to the crimping pins, so the protection sheet can be laid easily and accurately on the sheet laying table. This enables the work of crimping the protective sheet to be performed with high precision.

According to the first aspect of the present invention, since the protection sheet can be easily and accurately positioned with respect to the crimping pins, automatic assembly is possible and productivity can be greatly improved.

According to the first aspect, since the rigidity of the flange portion of the protective sheet can be increased and the flatness can be improved, the dimensional control of the protective sheet is easy and the product inspection in the manufacturing process is easy.

According to the second aspect of the present invention, since the gap is formed between the tape protection portion of the protection sheet and the sheet laying table, the tape protection portion can exhibit sufficient elasticity.
The magnetic tape can be sufficiently protected from shocks during transportation.

According to the third aspect of the present invention, since the thick flange portion for caulking is formed on the entire circumference of the protective sheet, the rigidity of the flange portion can be remarkably increased and the flatness thereof can be further improved.

According to the fourth aspect of the present invention, the synthetic resin injection gate is set in the flange portion. Therefore, injection molding of the protective sheet can be performed easily and with high precision, the gate processing is easy, and the productivity can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a step of crimping a protective sheet of a tape cassette that is an embodiment of the present invention.

FIG. 2 is a perspective view and a sectional view of a protective sheet of the present invention.

FIG. 3 is a cross-sectional view showing a modified example of the protective sheet of the present invention.

FIG. 4 is a cross-sectional view illustrating an injection molding die for a protective sheet of the present invention.

FIG. 5 is a cross-sectional view showing a modified example of the above injection molding die.

FIG. 6 is a cross-sectional view showing another modified example of the above injection molding die.

FIG. 7 is a plan view of the entire tape cassette.

8 is a cross-sectional view taken along the line AA of FIG.

FIG. 9 is a bottom view of the upper half of the tape cassette.

10 is an enlarged cross-sectional view taken along the line BB of FIG. 7 with the tape cassette housed in the hard case.

FIG. 11 is a perspective view of a conventional protective sheet.

FIG. 12 is a cross-sectional view illustrating a conventional crimping step of the protective sheet.

[Explanation of symbols]

 1 Upper half 1a Inner surface of upper half (inner surface of cassette housing) 3 Cassette housing 4, 5 Single flange reel 4a, 5a Single flange reel hub 4b, 5b Single flange reel flange 6 Magnetic tape 6a Upper edge of magnetic tape 14 Protective Sheet 14a Protective Sheet Tape Protective Section 14b Protective Sheet Side Wall 14c Protective Sheet Flange 16 Sheet Laying Table 16a Lower Surface of Sheet Laying Table 21 Caulking Pin 22 Caulking Hole 26, 27 Molding Die 28 Cavity 30 Injection Gate 32 gap

Claims (4)

[Claims] 1. A single-flange reel in which at least one of a pair of reels in which a magnetic tape is wound and housed in a cassette casing formed of synthetic resin is formed as a single-flange reel, and is opposite to the flange side of the single-flange reel. A sheet laying table and a plurality of caulking pins arranged on the outside thereof are integrally formed on the inner surface of the cassette housing on the side, and the flange side of the magnetic tape fitted to the single flange reel is opposite to the flange side. Lay the tape protection part of the protection sheet that protects the edge on the above-mentioned sheet laying table, insert the flange part for crimping of the protection sheet into the plurality of crimping pins, and melt these crimping pins. In the tape cassette that has been swaged by caulking, the protective sheet is injection-molded with a synthetic resin to reduce the wall thickness of the tape protective portion of the protective sheet, A tape cassette characterized by a thicker wall. 2. The tape cassette according to claim 1, wherein a gap is formed between the tape protection portion of the protection sheet and the sheet laying table. 3. The tape cassette according to claim 1, wherein the caulking flange portion having a large wall thickness is formed on the entire circumference of the protective sheet. 4. A tape cassette according to claim 1, wherein a synthetic resin injection gate is set on the flange portion.