JPH0782727B2 - Magnetic disk cassette - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk cassette having a flexible magnetic disk housed in a hard case, and more particularly to a shutter for opening and closing an opening for inserting a head.

[Background technology and its problems]

There is known a magnetic disk cassette in which a flexible magnetic disk having a diameter of 3.5 inches is housed in a hard case and digital data can be recorded and reproduced in this state. A shutter is attached to the magnetic disk cassette so as to be openable and closable in order to protect the magnetic disk. That is, the shutter is opened only during operation, the magnetic disk is exposed through the slot-shaped head insertion opening provided in the case, and when not operating, the shutter is closed and the opening is closed. By closing the opening in this way, foreign matter and dust are prevented from entering the case, and the magnetic disk is protected in the case.

Conventionally, this shutter has a U-shaped cross section made of metal such as stainless steel. A long hole having substantially the same shape as the opening of the case was formed in the shutter, and this shutter was slidably attached to the case. This shutter needs to be attached to the case so that it slides smoothly and the case does not come off easily. In addition, this shutter evenly adheres to the outer surface of the case,
It is necessary to prevent dust from entering the cassette by completely closing the opening. Therefore, the height of the opening of the shutter that holds the cassette case and the height of the guide projection in the shutter must be strictly determined so as to correspond to the standardized thickness of the cassette case.

Conventional shutters are made by drilling holes in stainless steel plates.
It had been processed by bending and deburring.
However, since the stainless steel flat plate is stored in a rolled state, stress may remain and it may be deformed. Therefore, it is difficult to perform highly accurate processing in the bending process.

Further, in the conventional shutter, when the shutter is attached to the case or when the shutter slides on the hard case, the hard case may be scraped by the guide projections, and dust generated by this may get into the case. was there. Further, since the metallic material is used, it is difficult to color the shutter and print the display of the manufacturer on the shutter. As described above, the conventional shutter has a large number of manufacturing steps, and the dimensional accuracy is severely required. Therefore, the shutter has to be expensive.

[Object of the Invention]

Therefore, an object of the present invention is to provide a magnetic disk cassette provided with a shutter having a shutter which is easy to manufacture and has a low cost in order to solve the above-mentioned drawbacks.

Another object of the present invention is to provide a magnetic disk cassette provided with a shutter that can evenly adhere to the outer surface of the case and prevent a gap from being formed between the case and the shutter.

It is still another object of the present invention to provide a magnetic disk cassette in which dust is prevented from entering the case without the case being scraped when the shutter slides on the case.

[Outline of Invention]

The present invention relates to a magnetic disk cassette including a magnetic disk, a case including the magnetic disk, and a shutter made of synthetic resin, which is slidably provided on the case and can be in a position when operating and a position when not operating. In, the shutter has a U-shaped cross section so that it holds the case.
A top plate, a bottom plate, a side plate connecting the top plate and the bottom plate, a head insertion opening formed in at least one of the top plate and the bottom plate, and in a state of being separated from the case,
Both the upper surface plate and the lower surface plate are closer to each other toward the non-coupling portion, and are curved inward.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1A and 1B are a top view and a bottom view of the entire magnetic disk cassette according to an embodiment of the present invention. In FIGS. 1A and 1B, 1 is an upper shell and 2 is a lower shell. The upper shell 1 and the lower shell 2 are, for example, ABS resin molded products containing an antistatic agent. A liner made of non-woven fabric such as rayon for preventing dropout and abrasion of the magnetic disk and generation of static electricity is thermally or ultrasonically welded to the inner surface of each of the upper shell 1 and the lower shell 2. The outer peripheral portion of the upper shell 1 and the outer peripheral portion of the lower shell 2 are joined by ultrasonic welding, and the magnetic disk 3 is housed in a case formed by combining the upper shell 1 and the lower shell 2. The magnetic disk 3 is a flexible magnetic disk based on a disk-shaped polymer film and having a magnetic layer formed uniformly on the lower surface thereof. A circular opening is formed in the center of the magnetic disk 3, and a ring-shaped center plate 4 is formed in this opening.
Is stuck. A substantially square motor shaft insertion hole 5 is formed in the center of the center plate 4, and a rectangular position regulating pin insertion hole 6 is formed at a position offset from the insertion hole 5 by a predetermined distance. A circular opening 7 is formed in the center of the lower shell 2, and the center plate 4 is arranged in the opening 7 with some play. Oblong holes 8 and 9 are formed in the upper shell 1 and the lower shell 2, and the magnetic disk 3 is exposed from the oblong holes 8 and 9.

Upper shell 1 including a portion in which slots 8 and 9 are formed
Also, recesses 10 and 11 are formed on the outer surface of the lower shell 2 and the shutter 1 having a U-shaped cross section shown in FIG.
2 is mounted slidably. A guide groove 13 is provided along the side edge of the outer surface of the lower shell 2, and the guide groove 13 is provided.
A protrusion protruding inside the shutter 12 is guided through the inside of the shutter 13. As shown by the solid line in FIGS. 1A and 1B,
The use state in which the slot 9 for inserting the head, the slot 8 for inserting the head pad and the slots 14, 15 formed in the shutter 12 are aligned with each other and the magnetic disk 3 is exposed to the outside, and FIG.
As shown by the phantom line in FIG. 1B, the shutters 12 slide so that the elongated holes 8 and 9 are closed and the magnetic disk 3 is covered with the shutter 12 in an unused state. The shutter 12 protects the magnetic disk 3 and prevents dust from entering.

Further, a lug 16 for preventing erroneous erasure is provided at one corner portion of the lower shell 2, and if the lug 16 is folded and removed, it cannot be erased. This lower shell 2
A pair of positioning holes 17 and 18 are provided at the two corners of the disk for positioning when the magnetic disk device is mounted on the disk recorder body. One of the positioning holes 17 is a long hole so that even if there is some error in the position of the hole, it can be tolerated. The other two corners not provided with the positioning holes 17 and 18 serve as reference planes, and the magnetic disk cassette is supported at the reference positions at the four corners. In this state, the magnetic disk 3 is rotated by a motor, and recording or reproducing of a digital signal or an analog signal is performed.

FIG. 2 is a front view, a bottom view and a side view of the shutter 12. The shutter 12 is formed by integrally molding a top plate 21, a side plate 23, and a bottom plate 22. The shutter 12 is made of a thermoplastic synthetic resin having excellent elasticity, low frictional resistance, and relatively high strength, such as polyoxymethylene resin. The shutter 12 has a U-shaped cross section, and when it is detached from the case, as shown in FIG. 2C and FIG. Are designed to be close together.

Oblong holes 14 and 15 are formed in the upper plate 21 and the lower plate 22, respectively. The bottom plate 22 has, for example, two rectangular cutouts 24 and
25 are formed, and along the inner peripheral edges of the cutouts 24 and 25, the guide projections 26 and
27 are formed. Further, the side plate 23 is formed with a protrusion 28 for locking the spring, which protrudes inward. In addition, at least the peripheral edge portion of the shutter 12 on the opening end side.
The outer corners of 29 and 30 are cut away.

The opening of the shutter 12 is widened and attached so that the case is inserted through this opening.
The shutter 12 holds the case so that the inner surfaces of the upper surface plate 21 and the lower surface plate 22 come into close contact with the respective surfaces of the upper shell 1 and the lower shell 2. A spring is interposed between the inside of the side plate 23 of the shutter 12 and the end surface of the case. The shutter 12 is the recess 10 of the upper shell 1 and the lower shell 2 and
Sliding 11 causes the elongated holes 8 and 9 to be opened and closed. When the magnetic disk cassette is not used, the upper plate 21 and the lower plate 22 of the shutter 12 close the elongated holes 8 and 9 due to the tension of the spring interposed between the shutter 12 and the cassette case, and the magnetic disk 3 is closed by the shutter 12. Be kept covered by.

The upper plate 21 and the lower plate 22 of the shutter 12 are, as described above,
The inner surfaces of the upper surface plate 21 and the lower surface plate 22 are evenly adhered to the bottom surfaces of the recesses 10 and 11 of the upper shell 1 and the lower shell 2 because they are closer to each other toward the peripheral edge of the opening end. .

FIG. 4 is an enlarged view of a part of the magnetic disk cassette shown in FIG. The projection 27 of the shutter 12 is slidably inserted into the guide groove 13, and the projection 26 is similarly slidably inserted into the guide groove 13 even though not shown. spring
One end 32 of 31 is inserted into a recess 33 formed in the cassette shell and locked. The other end 34 of the spring 31 is locked to the spring locking projection 28 of the shutter 12.

FIG. 4 shows a state in which the shutter 12 is biased to a non-use position by the spring 31. When the magnetic disk cassette is mounted on the disk recorder main body at the time of use, the shutter 12 is automatically moved against the spring force of the spring 31 by the operating portion of the disk recorder main body along with the sliding operation at the time of mounting. Then, the long holes 14 and 15 of the shutter 12 and the upper shell 1 and the lower shell 2
The long holes 8 and 9 are in the same operating state.

The upper surface plate 21 and the lower surface plate 22 of the shutter 12 may be warped due to changes over time. Top plate 21 and bottom plate
When the shutter 22 is warped, the upper plate 21 and the lower plate 22 are not evenly adhered to the recesses 10 and 11 when the shutter 12 is attached to the case, and the peripheral edge of the shutter 12 is lifted from the recesses 10 and 11. If the peripheral edge part floats up from the recesses 10 and 11 in this way, when the magnetic disk cassette is mounted on the disk recorder body, the protruding peripheral part and the regulation part of the insertion port of the disk recorder body will come into contact with each other to ensure smooth operation. There is a risk that it will not be able to be installed properly. However, in this embodiment, since the corners of the outer surface of the peripheral edge portions 29, 30 on the opening end side of the shutter 12 are cut off, as shown in FIG. Even if the edge portion of 36 and the peripheral portions 29, 30 come into contact with each other, smooth mounting can be performed.

The shutter 12 is molded by injection molding as an example. Injection molding is performed by injecting a synthetic resin from a gate into a space formed by two molds including a core and a cavity.

The mold for this purpose is to form the core 42 and the cavity 44 for forming the overall shape of the shutter 12 and the elongated holes 14 and 15 of the shutter 12, respectively, as shown in FIGS. 6 to 11. The slide cores 51 and 52 and the slide core 55 for forming the protrusions 26 of the shutter 12 and the slide core 56 for forming the protrusions 26 and 28 of the shutter 12 are formed.

A notch 24 corresponding to the position of the slide core 55 is formed to form the protrusion 26 inside the shutter 12, and
A notch 25 corresponding to the position of the slide core 56 is formed in order to form the protrusion 27 and the protrusion 28 inside. Where the protrusion
The notch 27 is formed in contact with the peripheral portion of the notch 25, and
A protrusion 28 is projected from the side plate 23 in an internal space corresponding to the position of 25. Therefore, one slide core 56 can form both of the two protrusions 27 and 28.

6A and 6B are a front view and a side view of a mold for molding the shutter 12 described above. FIG. 7 is A of FIG.
-A 'line sectional view, FIG. 8 is a BB' line sectional view of FIG. 6,
FIG. 9 is a sectional view taken along the line CC ′ of FIG. cavity
The core 42 fitted in the 44 has a convex portion 41 having the same shape as the internal space formed by the upper surface plate 21, the lower surface plate 22, and the side surface plate 23 of the shutter 12. A gate 58 for injecting the molten synthetic resin into the mold is provided on the top of the cavity 44.

As shown in FIG. 9, concave portions 45 and 46 into which the ends of the slide cores 55 and 56 are inserted are provided on the tip end surface of the convex portion 41 of the core 42. The concave portion 45 has a depth equal to the width of the convex portion 41 as shown in FIG. 7, and the concave portion 46 has a depth to the formation position of the protrusion 28 as shown in FIG. Steps 47 and 48 are formed on the bottom surfaces of the recesses 45 and 46, respectively. The shapes of the step portions 47 and 48 correspond to the protrusions 26 and 27, respectively.

On the front and back of the cavity 44, there are long holes for the shutter 12.
Slide core insertion ports 49, 50 having a shape corresponding to 14 and 15 are formed, and the slide core 5 is inserted through these insertion ports 49, 50.
1,52 is slid. As shown in FIGS. 7 and 8, slide core insertion ports 53, 54 into which rod-shaped slide cores 55, 56 are respectively inserted are formed on the front surface of the cavity 44. The positions of the slide cores 55 and 56 are cutouts 24 and 25 of the shutter 12. As shown in FIG. 8, the slide core 5
A step portion 57 having a shape corresponding to the protrusion 28 of the shutter 12 is formed at the tip of the convex portion 41 of the core 42 that comes into contact with the tip of the shutter 6.

Molten resin such as polyoxymethylene resin is introduced from the gate 58 into the mold, and the resin flows into the space between the cavity 44 and the core 42 into which the slide cores 51, 52 and 55, 56 are inserted. Come on. Then, the resin is cooled and solidified in the mold. In this case, regarding the surface temperature of the mold, the surface temperature of the cavity 44 is set lower than the surface temperature of the core 42. Therefore, this solidification starts from the resin around the gavity 44.

After the liquid resin is cooled and solidified in the mold, the 10th
As shown in the figure, the slide cores 51, 52 and 55, 56 are laterally slid by a predetermined distance, and the mold comprising the core 42 and the cavity 44 is separated as shown in FIG. The shutter 12 having the shape shown in FIG. 2 is taken out of this mold. That is, the liquid resin is poured into the gap between the cavity 44 and the core 42, so that the upper surface plate 21, the lower surface plate 22, and the side surface plate 23.
Is formed.

As shown in FIG. 6, the slide cores 51 and 52 are inserted into the cavity 44, and the resin does not flow into this portion,
Slotted holes 14 and 15 are formed here. Slide core 55 and
56 is inserted in the core 44, the resin does not flow into this portion, and the notches 24 and 25 are formed therein. A step 47 is formed in the recess 45 at the tip of the protrusion of the core 42.
A gap is formed by the core 47 and the slide core 55 abutting each other, and the resin flows into the gap to form the protrusion 26. As shown in FIG. 7, FIG. 8 and FIG.
A step portion 48 is formed on the step portion 46 at the tip of the convex portion 41 of
A gap is formed by the step portion 48 while the core 42 and the slide core 56 are in contact with each other.
27 is formed. At the same time, a step 57 is formed at the tip of the convex portion 41.
Since the resin is formed, the resin flows into this step 57,
The protrusion 28 is formed.

As described above, the surface temperature of the mold is controlled so that the surface temperature of the cavity 44 is lower than the surface temperature of the core 42. Therefore, the resin in the vicinity of the surface of the cavity 44 contacts the surface of the core 42 in the vicinity. It solidifies faster than other resins. Therefore, the volume reduction near the core 42 occurs later than the volume reduction near the cavity 44. This strain is released after being taken out of the mold, so that the shutter 12 is curved inward so that the opening end is narrowed, as shown in FIGS. 2C and 3.

The present invention, like the above-described embodiment, uses the slide core 5
Therefore, the present invention can be applied not only to the shutter in which the notches 24 and 25 are formed by inserting the 5,56 from the front, but also to the shutter in which the notches 24 and 25 are not formed by inserting the slide cores from both side surfaces. . As shown in FIGS. 12 to 17,
It shows a mold for integrally forming a shutter without forming the notches 24 and 25. However, the reference numerals of the respective parts of the shutter except the notches 24 and 25 are the same as those related to the shutter 12.

The mold is a core 61 and a gaviity 63 and a long hole 1 for the shutter
It is composed of slide cores 69 and 70 forming the respective parts 4 and 15 and slide cores 73 and 74 for forming the projections 26, 27 and 28 of the shutter. 12A and 12B are a front view and a side view of the mold, and FIG. 13 is a sectional view taken along the line DD ′ of FIG.
FIG. 14 is a sectional view taken along the line EE ′ of FIG. 12, and FIG. 15 is an F of FIG.
It is a -F 'line sectional view. Cavity 63 and this cavity
The shape of the shutter is formed as a whole by the core 61 having the convex portion 62 fitted in the 63.

At the tip of the convex portion 62 of the core 61, the projections 26 and 27 of the shutter are attached.
Stepped portions 65 and 66 having a shape corresponding to are formed. Also,
A protrusion 64 is formed at the tip of the protrusion 62.
The groove 64 has a width approximately equal to the thickness of the projection 28 of the shutter.
Are formed.

The core 61 is fitted in the cavity 63. In the cavity 63, four slide core insertion openings are formed. The slide cores 69 and 70 are inserted into the slide core insertion openings, respectively. The shapes of the end surfaces of the slide cores 69 and 70 correspond to the elongated holes 14 and 15 of the shutter. The slide cores 73 and 74 are inserted from the slide core insertion openings, respectively. A protrusion 76 is formed at the tip of one slide core 74.

Liquid resin is injected from the gate 75 as in the case of the example of the mold. The resin thus injected flows into the voids in the mold and is solidified. Slide cores 69 and 70 are number 16
As shown in the figure, the slide cores 73 and 74 are similarly slid as shown in FIG. 17, the core 61 is extracted from the cavity 63, and the two are separated as shown in FIG. . In this way, the shutter is formed.

That is, the resin from the gate 75 flows into the space between the core 61 and the cavity 63, and the upper plate 21, the lower plate 22 and the side plate 23 of the shutter are formed. Since the slide cores 69 and 70 are inserted in this space, the resin does not flow into this portion and the elongated holes 14 and 15 are formed. On the contact surface between the end surface of the convex portion 62 of the core 61 and the slide cores 73 and 74, gaps are formed by the step portions 65 and 66, and resin flows into the gaps to form the protrusions 26 and 27, respectively. The resin flows into the gap formed by the groove 72 formed on the protrusion 71 of the convex portion 62 and the protrusion 76 formed on the slide core 74, and the protrusion 28 is formed.

By controlling the surface temperature of the core 61 and the cavity 63 when the synthetic resin is solidified in the same manner as described above, each of the upper plate 21 and the lower plate 22 of the shutter is removed with the shutter off the case of the disk cassette. The peripheral portion is curved inward.

〔The invention's effect〕

According to the present invention, since the shutter is formed of synthetic resin, the manufacturing process can be simplified and the manufacturing cost can be reduced. Further, since the shutter is formed of synthetic resin in this way, the case is not scraped by the shutter when the shutter is attached to the case or when the shutter slides on the case, and dust generated by the case is removed from the case. Never enter inside. In addition, the top plate and the bottom plate of the shutter are curved inward so that the top plate and the bottom plate are closer to each other toward the non-connecting portion, so that the head insertion port and the pad insertion port of the case are completely covered by the shutter. Can be occluded.
Further, since each part of the peripheral edge portion on the opening end side is cut off at the peripheral edge portion of the shutter, the magnetic disk cassette can be smoothly attached to the disk recorder body. Therefore, according to the present invention, it is possible to realize, at low cost, a magnetic disk cassette which is excellent in operability and has a shutter capable of sufficiently protecting the magnetic disk in the case.

[Brief description of drawings]

FIG. 1 is a top view and a bottom view of an embodiment of the present invention.
The figure is a front view of a shutter in one embodiment of the present invention,
FIG. 3 is a bottom view and a side view, FIG. 3 is a sectional view of a shutter according to an embodiment of the present invention, FIG. 4 is a partially enlarged view of a shutter according to an embodiment of the present invention, and FIG. 5 is an embodiment of the present invention. 6 is a cross-sectional view used for explaining the mounting of the shutter, FIG. 6 is a front view and a side view of an example of a mold for molding the shutter in one embodiment of the present invention, and FIGS. 7, 8, and 9 are the present invention. FIG. 10 is a cross-sectional view of an example of a mold for molding a shutter in one embodiment of the present invention, FIG. 10 and FIG. 11 are cross-sectional views used to explain an example of a mold for forming a shutter in one embodiment of the present invention, and FIG. A front view and a side view of another example of a mold for forming a shutter in one embodiment of the present invention, FIG. 13, FIG.
14 and 15 are cross-sectional views of another example of the mold for molding the shutter in one embodiment of the present invention, FIG. 16, FIG. 17, and FIG.
FIG. 18 is a sectional view used for explaining another example of the mold for molding the shutter in one embodiment of the present invention. 1: Upper shell, 2: Lower shell, 3: Magnetic disk, 12: Shutter, 13: Guide groove, 21: Top plate, 22: Bottom plate, 23: Side plate, 24,
25: Notch, 26, 27: Protrusion, 28: Protrusion for spring locking, 31: Spring, 42, 61: Core, 44, 63: Cavity, 51, 52, 55, 56, 6
9,70,73,74: Slide core.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-36473 (JP, A) Actually opened 58-17683 (JP, U) Actually opened 57-180883 (JP, U) Actually opened 58- 7265 (JP, U) Actual Open Sho 58-48082 (JP, U) Actual Open Sho 58-7264 (JP, U)

Claims (1)

[Claims] 1. A magnetic disk, a case including the magnetic disk, and a shutter made of a synthetic resin, which is slidably provided on the case and can take a position when operating and a position when not operating. In the magnetic disk cassette, the shutter has at least the upper surface plate, the lower surface plate, the side surface plate connecting the upper surface plate and the lower surface plate, the upper surface plate, and the lower surface plate so as to sandwich the case with a U-shaped cross section. With an opening for inserting a head formed on one side and in a state of being separated from the case, both of the upper plate and the lower plate are closer to each other toward the non-connecting portion, and are curved inward. A magnetic disk cassette characterized in that it is formed into a shape.