JP2002093105A - Magnetic disk cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the buckling of a shutter spring consisting of a long and narrow cylindrical coil spring which energizes a shutter member toward a closed position in a magnetic disk cartridge. SOLUTION: The long and narrow cylindrical coil spring 6 is shrinked and mounted along the internal surface of a connection plate part 53 by locking one end of the coil spring 6 with a spring seating piece 55 formed at a edge side in the opening direction of a shutter window part 54. A tongue-shaped piece 59 for retaining spring which is bent in the opening direction of the shutter member 5 from the spring seating piece 55 and is extended in almost parallel to the connection plate part 53, is provided so that a long and narrow space for housing the coil spring 6 is formed between the piece 59 and the connection plate part 53.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin, large-capacity magnetic disk cartridge in which a disk-shaped magnetic disk medium is accommodated in a flat cartridge case, and more particularly to a magnetic disk access to the cartridge case. The present invention relates to a structure of a shutter member that opens and closes a window.

[0002]

2. Description of the Related Art Conventionally, a magnetic disk medium (a so-called floppy disk) in which a magnetic layer is provided on both sides of a disk-shaped base made of a flexible polyester sheet or the like and magnetically recorded on the magnetic layer by a magnetic head while being driven to rotate. (Registered Trademark) disk is provided in a flat case, and is mainly used as a recording medium for a computer because of its advantages such as easy handling and low cost.

[0003] The case is provided with a case window through which a magnetic head for magnetic recording and reproduction can be accessed on one or both sides of the magnetic disk medium. Further, in order to prevent intrusion of dust and the like when not in use. A shutter member slidable between an open position for opening the window portion and a closed position for closing the window portion is mounted, and the shutter member is urged in a closing direction by a shutter spring.

By the way, the miniaturization of the computer using the above-mentioned magnetic disk cartridge has progressed, and the notebook type personal computer has become widespread. An external system without a built-in disk drive device is now being sold. The adoption of this external method is excellent in terms of portability of small personal computers.However, for example, there is a problem that a large amount of data cannot be recorded and reproduced because magnetic disk cartridges cannot be used at the carrying destination of small personal computers. This causes a problem that data cannot be recorded on a plurality of magnetic disk cartridges.

[0005] In view of these points, some small personal computers have a PC card slot (conforming to the PCMCIA specification) in which a PC card is mounted so as to support an external interface and additional memory. Thus, it has been proposed to configure an external storage device using a magnetic disk cartridge.

A PC that can be inserted into the PC card slot
The specifications of the card are type II, the thickness is 5.0 mm, and the thickness of the magnetic disk cartridge and the disk drive device is to be configured within this thickness. It must be made ultra-thin.

[0007] Even when the magnetic disk cartridge is made thin in this manner, since a large recording capacity is required as a recording medium, the transfer rate is increased when the recording density is increased to secure the maximum recording capacity. High speed (2600-4500rpm)
) Must be driven in rotation.

In consideration of the above points, it is necessary to design the basic structure of the magnetic disk cartridge. In particular, the magnetic disk medium is rotatably housed inside while ensuring the strength of the cartridge case. It is an important issue to secure a space to be used. In other words, in the case where the upper and lower shells of the divided structure are joined in a lid-like manner as in a cartridge case of a conventional magnetic disk cartridge,
Since the regulation in the thickness direction of the cartridge case is strict, the thickness of the flat case becomes thin as a result, and it becomes impossible to maintain a desired mechanical strength. If the strength of the cartridge case is insufficient, the cartridge case may be deformed during loading or unloading operations to the drive unit or during handling outside of the drive unit, and the magnetic disk media may rub against the inner surface of the case, affecting the recording / reproducing characteristics. It may cause a decline in sex.

Therefore, the present inventor has constructed a cartridge case with a base plate made of a synthetic resin and a pair of metal cover cases attached to the upper and lower surfaces of the base plate, and provided a concave portion on the upper surface of the base plate.
A magnetic disk medium is rotatably accommodated in the concave portion, and a case window accessible to the magnetic head is provided in such a manner that the base plate, the upper and lower cover cases, and their front edges are notched toward the center. A magnetic disk cartridge was proposed earlier.

In this case, in order to open and close the case window, the upper and lower face plates are connected by a front end connecting plate portion to have a substantially U-shaped cross-sectional shape, and the upper and lower face plates are separated from the connecting plate portion. It has been considered that a metal shutter member provided with a shutter window portion opened to communicate with the portion is slidably mounted in the opening and closing direction between the base plate and the upper and lower cover cases.

[0011]

When the shutter member is incorporated inside the upper and lower cover cases, it is necessary to set the shutter spring for urging the shutter member in the closing direction inside the shutter member. ,
Therefore, a spring accommodating portion is defined between the base plate and the upper and lower cover cases at a front edge of the cartridge case on the opening side with respect to the case window, and an elongated cylindrical coil spring is shuttered in the spring accommodating portion. It is conceivable that the member is contracted along the inner wall surface of the connecting plate portion. In this case, one end of the coil spring is locked by a spring receiving piece cut and raised from the shutter member near the edge of the shutter window on the opening direction side, and the other end of the coil spring is located on the shutter opening direction side of the spring housing portion. May be locked at the end wall surface.

However, due to the space of the spring accommodating portion, the cylindrical coil spring needs to have a small wire diameter and a small coil diameter and a long coil length. Easy to buckle in any direction. In particular, since one end of the coil spring is locked near the edge of the shutter window on the opening direction side, when the shutter member is in the closed position, the coil spring is set across the case window, Even if the three sides in the radial direction of the coil spring are surrounded by the upper and lower face plate portions and the connection plate portion, the case window side is open, so it is impossible to prevent the buckling of the coil spring at this portion. . For this reason, when the shutter is compressed in the opening direction from the closed position, the coil spring buckles, and an accident that a part of the coil spring jumps out to the case window side is likely to occur.

In view of such circumstances, the present invention provides a magnetic disk cartridge capable of effectively preventing buckling of a coil spring when a cylindrical coil spring is used as a shutter spring for urging the shutter member in a closing direction. The purpose is to provide.

[0014]

According to the present invention, there is provided a flat cartridge case for rotatably storing a disk-shaped magnetic disk medium, the cartridge case being accessible to a magnetic head. In a magnetic disk cartridge in which a case window is formed and a shutter member for opening and closing the case window is slidably attached to the cartridge case in the opening and closing direction, the cartridge case has a circular shape for accommodating a magnetic disk medium. A base plate with a recess, and a cover case attached to the top and bottom of the base plate,
The shutter member is disposed between the base plate and the cover case, and the shutter member is formed in a U-shape by an upper plate portion, a lower plate portion, and a connecting plate portion connecting these upper and lower plate portions on one side. A shutter window portion that is formed in a cross-sectional shape of a cross-section and that opens from the connection plate portion to communicate with the upper and lower face plate portions, and a cylindrical coil spring that urges the shutter member in the closing direction is provided on the shutter window portion. One end is locked by a spring receiving piece formed in the vicinity of the edge on the opening direction side, is compressed along the inner wall surface of the connecting plate portion, is bent from the spring receiving piece, and faces the opening direction of the shutter member. And a spring holding tongue extending substantially parallel to the connecting plate is provided in such a manner that an elongated space for accommodating the coil spring is formed between the tongue and the connecting plate. It is.

The length of the spring holding tongue is greater than the width of the case window in the shutter member opening / closing direction and from the opening edge of the shutter window to the opening edge of the upper and lower plate portions. Is preferably equal to or less than the width.

It is preferable that the spring holding tongue slides against the front edge of the base plate so as to perform a guiding action when the shutter member is opened and closed.

In this case, the spring holding tongue is provided so that the spring holding tongue has a stable guide effect when the shutter member is opened and closed and does not wear even when it comes into contact with the base plate. It is preferable that the piece is subjected to a curved surface treatment on its side edge, or is punched in a direction in which no burrs appear on the front edge side of the base plate.

[0018]

According to the present invention, the cartridge case includes a base plate and cover cases respectively attached to the upper and lower surfaces of the base plate, and the base plate has a concave portion on its surface. Since the magnetic disk medium is rotatably housed in the space defined by the cover case and the cover case, the compression direction and the bending direction of the cartridge case are formed by forming the medium housing space by attaching the cover case to the base plate. Can be improved in strength. In particular, by configuring the cover case with a high-strength material such as a metal plate,
In combination with the base plate, the strength required for a flat case can be secured, the dimensional accuracy can be maintained without deformation such as warping even if the case is thin, and the characteristics required for the usage mode as a magnetic disk cartridge can be obtained and reliability can be obtained. There is an advantage that a good assembling property can be obtained.

Since the shutter member is housed inside the upper and lower cover cases, the shutter member is prevented from coming off due to insufficient strength due to downsizing of the shutter member.
It also becomes strong against impacts such as dropping, and the assemblability becomes good.

Also, a spring retainer bent from the spring receiving piece for locking one end of the cylindrical coil spring for urging the shutter member in the closing direction toward the opening direction of the shutter member and extending substantially parallel to the connecting plate portion. Since the tongue piece is provided in such a manner that an elongated space for accommodating the coil spring is formed between the connecting plate and the connecting plate, the coil spring straddles the case window when the shutter member is closed. Even in the position, the four sides in the radial direction of the coil spring are completely surrounded by the upper and lower face plate portions, the connecting plate portion, and the spring holding tongue pieces, so that buckling of the coil spring can be effectively prevented. it can.

Further, by bringing the spring holding tongue into sliding contact with the front end face of the base plate, it is possible to perform a guide action for the opening and closing operation of the shutter member, so that the opening and closing operation of the shutter member is stabilized. Can be done.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a perspective view of a magnetic disk cartridge according to an embodiment of the present invention, showing a state in which a window for inserting a magnetic head is closed by a shutter member, as viewed from above. FIG. 2 is a perspective view of a state in which the magnetic head insertion window is opened as viewed from the lower surface side. FIG. 3 is an exploded perspective view of the magnetic disk cartridge. In addition, in order to clarify the structure, the thickness and the like of each part in the drawings are shown in proportions different from actual dimensions.

The magnetic disk cartridge 1 has a disk-shaped magnetic disk medium 10 (see FIG. 3) rotatably housed in a flat cartridge case C.
The cartridge case C includes a base plate 2 serving as a central member.
And a substantially planar upper cover case 3 and a lower cover case 4 attached to the top and bottom of the base plate 2. The magnetic disk medium 10 has a disk-shaped base made of a flexible polyester sheet and the like, on both sides of which magnetic layers are provided, and a center core 11 is fixedly integrated at the center thereof.

The lower surface of the cartridge case C is provided with a hole 7 for enabling chucking between the drive motor of the drive device and the center core 11, and the magnetic disk medium 10 is positioned so that the bottom of the center core 11 faces the hole 7. Are housed in the cartridge case C.

A window 8 is formed at the front end of the cartridge case C with respect to the direction of insertion D (arrow in FIG. 1) with respect to the drive device. The window 8 is vertically penetrated and opened from the front end faces of the base plate 2 and the upper and lower cover cases 3 and 4 toward the center thereof in a rectangular shape (see FIG. 2). A shutter member 5 for opening and closing the portion 8 is built inside the upper and lower cover cases 3 and 4 so as to be slidable in the left-right direction.

With the structure of the window 8 as described above, the recording / reproducing magnetic head can be inserted into the window 8 from the front end face side of the cartridge case C without opening and closing greatly, and a built-in shutter member. The use of 5 prevents the shutter member 5 from coming off due to insufficient strength due to miniaturization, becomes tough against dropping, etc., and has good assemblability.

Next, the structure of each component will be specifically described.

First, as shown in the plan view of FIG. 4A and the bottom view of FIG. 4B, the base plate 2 is formed of a synthetic resin such as an ABS resin or a POM resin and has a substantially rectangular shape. A circular recess 2 for accommodating the magnetic disk medium 10 in the center of the upper surface
1 is formed, and a center core receiving hole 27 is opened at the center of the bottom plate of the concave portion 21. Further, the front portion of the bottom plate of the concave portion 21 is removed in a substantially rectangular shape to form a space 22 in which a lower plate portion 52 of the shutter member 5 described below can move, and the central portion of the front end portion of the base plate 2 extends in the front-rear direction. The window portion 8 that has been removed and communicates with the space 22 is vertically opened and opened. The front surface of the front wall on one side (left side in FIG. 4 (a), right side in FIG. 4 (b)) of the window 8 of the base plate 2 is retracted from the front surface of the front wall on the other side, and the spring storage portion. 23, an elongated cylindrical coil spring 6 described later as a shutter spring is disposed in this portion. The space 22 may be formed in a thin groove shape from the bottom surface side when there is a margin in the thickness direction of the base plate 2.

Further, the corner portions 25 of the four corners of the base plate 2 are formed so as to protrude in the vertical direction and have a large thickness and project outward, and the four corner portions of the upper and lower cover cases 3 and 4 correspond to the corner portions. When the upper and lower cover cases 3 and 4 are fitted to the base plate 2, the corner portions 25 of the base plate 2 are exposed to the outside. Each corner portion 25 is provided in such a shape that its surface projects flush with the surface of the upper and lower cover cases 3 and 4 or outwards.

By exposing the corner portion 25 of the base plate 2 to the outside as described above, when a shock or the like at the time of a drop acts, the corner portion 25 can absorb the shock, and can be inserted into the drive device and inserted. At the time of unloading operation, it is prevented from getting stuck and stable operation is ensured. In each corner portion 25, a hole 26 penetrating in the vertical direction (a hole having an intermediate depth without penetrating) may be provided.
Is provided so as to obtain a larger buffering action at the time of a drop impact. The base plate 2 has a strength that allows deformation that does not hinder recording and reproduction of the magnetic disk medium 10. It is preferable that the base plate 2 be made of elastic plastic from the viewpoint of absorbing the impact, and it is preferable that the base plate 2 contains a lubricant from the viewpoint of sliding with the shutter member 5 to improve dimensional accuracy. From the viewpoint of improving the assemblability with the cover cases 3 and 4, it is preferable to include a filler material. In the case of the present embodiment, the corner of one of the front corners 25 is notched diagonally to form the erroneous insertion preventing portion 16.

As shown in FIG. 4B, the front edge of the bottom surface of the base plate 2 is
On the side opposite to the side, a guide groove 24 with which a guide claw 56 of a shutter member 5 described later is engaged is formed. Further, when the shutter member 5 is mounted on the base plate 2, the guide claw 56 is inserted into the guide groove 24. A leading notch 29 is formed. Further, on the upper surface of the base plate 2, supporting edges 28, 28 flush with the peripheral wall of the circular recess 21 are formed adjacent to the left and right corner portions 25, 25, and also on the bottom surface of the base plate 2. Support edges 28, 28 flush with the bottom surface of the base plate 2 are formed. These supporting edges 28 have a role of supporting the corner edges of the upper and lower cover cases 3 and 4 to secure an operation space for the shutter member 5 and to ensure a stable opening and closing operation of the shutter member 5.

The upper and lower cover cases 3 and 4 are made of a high-strength material such as a pressed stainless steel plate. The upper cover case 3 and the lower cover case 4 have a substantially symmetric shape, and the four corners are rectangular. The case window 8 having a flat rectangular shape is opened at the center of the front part, and the front, rear, left and right edges are bent at right angles, so that the front walls 31, 41, both side walls 32,
42, constituting the rear wall portions 33 and 43. Case window 8
1 side (left side in FIGS. 1 and 3 and right side in FIG. 2)
The front wall portions 31 and 41 are formed to have a low height, and when the upper and lower cover cases 3 and 4 are attached to the base plate 2, the slit 18 between the upper and lower front wall portions 31 and 41 (FIGS. 1 and 2). Reference) is formed. A shutter opening / closing lever 61 described later on the drive device side is inserted into the slit 18 and moves along the slit 18 to open the shutter member 5. A notch is formed in the front wall portions 31 and 41 on the opposite side (the right side in FIGS. 1 and 3 and the left side in FIG. 2) with respect to the case window portion 8, that is, the end portion side of the portion located in front of the spring storage portion 23. The front wall portions 31 of the upper and lower cover cases 3 and 4 are formed.
When the rectangular spring insertion port 19 (FIG.
And FIG. 2) are formed and used for mounting an elongated cylindrical coil spring 6 as a shutter spring.

On the upper surface of the central portion of the upper cover case 3,
A concave portion 35 serving as a label attaching portion is formed, and a bottom surface of the concave portion 35 projects downward. The recess 35 is provided in the rotation area of the magnetic disk medium 10 in an assembled state. A hole 7 corresponding to the center core housing hole 27 of the base plate 2 is opened at the center of the lower cover case 4.

When the upper and lower cover cases 3 and 4 are assembled to the base plate 2, a shutter member 5 is provided between the upper and lower surfaces of the base plate 2 and the inner surfaces of the upper and lower cover cases 3 and 4 at the front portion. The dimension is set so that a thin space in which the slidable member extends can be formed extending in the left-right direction. The fixing method of assembling the base plate 2 and the upper and lower cover cases 3 and 4 is such that the contact portions of the upper and lower cover cases 3 and 4 are joined to each other by spot welding as shown by a reference symbol S in FIGS. Done by

FIG. 5 is a perspective view schematically showing the structure of the shutter member 5, and FIG.
7A is a plan view of the shutter member 5 with a partial cross section, FIG. 7B is a side view thereof, and FIG. 7C is a bottom view thereof. In FIG. 6, a mountain fold line when the shutter member 5 is bent is indicated by a broken line.

The shutter member 5 is inserted between the base plate 2 and the upper and lower cover cases 3 and 4 and into the moving space 22 opened to the base plate 2 on the lower surface side, and is slidably mounted in the left and right opening and closing directions. You. The shutter member 5 is made of metal, and is formed of, for example, a stainless steel plate or an aluminum plate to have a substantially U-shaped cross section as shown in FIGS. 5 and 7B. Are connected by the connecting plate 53 at the front end,
The height of the connecting plate portion 53 is formed slightly larger than the thickness of the front portion of the base plate 2. Then, a shutter window portion 54 is formed by being cut out in a substantially rectangular shape from the connecting plate portion 53 to the upper surface plate portion 51 and the lower surface plate portion 52. The shutter window 54 is provided in the cartridge case C
And has a size substantially coinciding with the window portion 8 and communicates with the window portion 8 during the opening operation. The shutter window 54 is provided at a position deviated in the closing direction from the center of the shutter member 5, and a closed area for closing the case window 8 together with the connection plate 53 is formed adjacent to the opening direction side of the shutter window 54. Have been. This closed area is the area to the left of the shutter window 54 in FIG. 7A, and the area to the right of the shutter window 54 in FIG. 7B.

The top plate 51 of the shutter member 5 is shown in FIG.
As is clear from the development of FIG.
A spring receiving piece 55 protruding into the shutter window portion 54 adjacent to the connecting plate portion 53 at the edge 51a on the side of the closed region. 59 extends along the edge 51a. The spring receiving piece 55 is connected to the edge 51.
The one end of an elongated cylindrical coil spring 6 as a shutter spring, which is bent at a substantially right angle along a mountain fold line a, which is an extension of a, and is compressed along the inner wall surface of the connection plate portion 53 in the closed area, is locked. .

The spring holding tongue piece 59 is bent at a substantially right angle along a mountain fold line b substantially at right angles to the edge 51a, and is substantially parallel to the connecting plate 53 toward the opening direction of the shutter member 5. An elongated prism-shaped space 60 (FIG. 7A) that extends and accommodates the coil spring 6 is formed between the connecting plate portion 53 and the elongated space 60. The length of the spring holding tongue piece 59 is not less than the width of the case window 8 in the shutter member opening / closing direction, and the edge 5 of the shutter window 54 on the opening direction side.
It is preferable that the width W is equal to or less than the width W (FIG. 7A) from 1a to the edge in the opening direction of the upper and lower plate portions 51, 52. The other end of the coil spring 6 is engaged with an end wall of the spring accommodating portion 23 of the base plate 2, and the shutter member 5 is biased in the closing direction by the coil spring 6 and is held at the closed position.

A guide claw 56 is cut and raised inward in the vicinity of the connecting plate portion 53 on the lower surface plate portion 52 on the closing direction side with respect to the shutter window portion 54. A notch 57 into which a tip of a shutter opening / closing lever 61 of a drive device described later is inserted is formed from an edge on the closing direction side, and a shutter opening / closing lever is provided at an end of the notch 57 on the window 54 side. An engaging piece 58 is formed to be bent inward to engage with the tip of 61 at the surface.

Referring to FIG. 3 again, a protective sheet 12 made of a plastic sheet or the like obtained by subjecting the surface of a PET sheet to slipping (Teflon (registered trademark) processing) is interposed above and below the magnetic disk medium 10. . The protective sheet 12 has a substantially C-shape by removing a portion corresponding to the window portion 8 in the radial direction, and has an opening 12 a formed in a portion opposite to the window portion 8.
Are fixed to the inner surface of the upper cover case 3 and the bottom surface of the base plate 2 from the magnetic disk medium 10 side.
2 is fixed. The cleaning member 13 has a raised surface on the side facing the magnetic disk medium 10 and comes into contact with the surface of the magnetic disk medium 10 to remove dust on the surface. An adhesive is applied to the opposite surface of the cleaning member 13.

The magnetic disk cartridge 1 as described above
Is assembled by fixing the protection sheet 12 to the circular recess 21 of the base plate 2 and the lower surface of the upper cover case 3 in advance by fixing the cleaning member 13, and setting the magnetic disk medium 10 in the circular recess 21 of the base plate 2. The shutter member 5 is mounted from the front with its guide claw 56 engaged with the guide groove 24 through the notch 29 of the base plate 2. Subsequently, the upper cover case 3 and the lower cover case 4 are fitted to the base plate 2 from above and from below, respectively, to be integrated. As a result, the upper surface of the circular recess 21 of the base plate 2 is covered with the upper cover case 3, and the flat space defined by the bottom surface of the upper cover case 3 and the upper surface of the circular recess 21 becomes a storage space for the magnetic disk medium 10. The magnetic disk medium 10 is rotatably stored. Thereafter, the coil spring 6 is inserted into the spring accommodating portion 23 while bending the coil spring 6 from the spring insertion opening 19 in the front wall portion of the upper and lower cover cases 3 and 4, and the distal end thereof is brought into contact with the spring receiving piece 55 of the shutter member 5, The assembly is completed by pushing the rear end portion into the storage portion 23 while shrinking it. The shape of the spring insertion opening 19 prevents the assembled shutter spring 6 from coming off.

The magnetic disk cartridge 1 as described above
When the shutter opening / closing lever 61 described below is inserted into the notch portion 57 of the shutter member 5 through the front end slit 18, when the shutter opening / closing lever 61 is inserted into the drive device, Window 8
By moving the shutter member 5 toward the engaging member 58, the shutter member 5 is moved in the opening direction. The drive unit has a magnetic head at the back, and a drive unit is provided at the bottom so as to be able to move up and down, and a spindle is engaged with the center core 11 of the magnetic disk medium 10 of the inserted magnetic disk cartridge 1 so that the disk is The medium 10 is configured to be driven to rotate.

FIG. 8 is an enlarged view of a main part showing a state where the shutter member 5 is held at the closed position. FIG. 9 is a main part showing a state where the shutter member 5 is moved to the open position by the shutter opening / closing lever 61. It is an enlarged view. 8 and 9, a part of the shutter member 5 is formed in a cross section, and the upper cover case 3 is omitted.

As is apparent from FIG.
The coil spring 6 housed therein is compressed between the base plate 2 and the spring receiving piece 55 of the shutter member 5 to hold the shutter member 5 in the closed position. In this state, the coil spring 6 straddles the case window portion 8, but the tongue piece 59 for holding the spring extends substantially in parallel with the connecting plate portion 53 from the spring receiving piece 55 toward the opening direction of the shutter member 5. It is present on the case window 8 side. Therefore, while the shutter member 5 moves from the closed state to the open position in FIG. 9, the four sides in the radial direction of the coil spring 6 are connected to the upper and lower face plate portions 51 and 52, the connecting plate portion 53, and the spring holding tongue piece 5.
9, the buckling of the coil spring 6 can be effectively prevented.

If the shutter member 5 is not provided with the tongue piece 59 for holding down the spring, when the shutter member 5 is operated from the closed position toward the open direction, the coil spring 6 is compressed. As shown in FIG. 10, the coil spring 6 buckles at the case window 8 and a part 6
a may protrude toward the case window 8.

Further, by setting the size of the spring receiving piece 55 such that the spring holding tongue piece 59 comes into sliding contact with the front surface of the base plate 2 when the shutter member 5 is opened and closed, the spring holding tongue piece 59 is Shutter member 5
Can act as a guide member for the opening / closing operation of the shutter member 5, and in combination with the provision of the guide claw 56 in the shutter member 5, the opening / closing operation of the shutter member 5 can be performed stably.

Further, in order to obtain a stable guide effect by the spring holding tongue piece 59, the spring holding tongue piece 59 is subjected to a curved surface treatment on its side edge, and a burr is formed on the front edge side of the base plate 2. It is preferable that the sheet is punched out in a direction not to come out.

Further, according to the embodiment, the cartridge case C includes the base plate 2 and the cover cases 3 and 4 attached to the base plate 2, and the base plate 2 is formed in a circular recess 21 having a planar shape. The magnetic disk medium 10 is rotatably accommodated in the space defined by the circular concave portion 21 and the cover case 3, so that the base plate 2 and the magnetic disk medium 10 together with the shutter member 5 etc. Attaching of the necessary components can be ensured, and by attaching the cover cases 3 and 4 to the base plate 2, the strength of the cartridge case C in the compression direction and the bending direction can be improved while defining a medium accommodation space. In particular, by forming the cover cases 3 and 4 from a high-strength material such as a metal plate, the strength required as a flat case can be secured in combination with the base plate 2, and even if the cover is thin, there is no deformation such as warpage and dimensional accuracy. Can be maintained, characteristics required for a mode of use as a magnetic disk cartridge can be obtained, reliability can be secured, and good assemblability can be obtained.

Since the shutter member 5 is housed inside the cover cases 3 and 4, the shutter member 5 is prevented from coming off due to insufficient strength due to the miniaturization of the shutter member 5, and is resistant to impacts such as dropping. It becomes stronger and the assemblability becomes better.

Further, as shown in FIG. 4, a guide groove 2 for engaging the guide claw 56 of the shutter member 5 to guide the opening / closing operation of the shutter member 5 is formed on the back surface of the base plate 2.
4 is formed along the front edge of the base plate 2, and the notch 29 communicating with the guide groove 24 from the front edge of the base plate 2 is formed in the base plate 2 so as to correspond to the guide claw 56. When the shutter member 5 is mounted on the base plate 2, the shutter member 5 can be mounted on the base plate 2 in a state where the guide claws 56 are engaged with the guide grooves 24 without opening the upper and lower face plate portions 51 and 52. Since no load is applied to the connecting plate portion 53 and the shutter member 5 is not deformed, the opening and closing operation of the shutter member 5 is stabilized.

Further, as shown in FIG. 5, a notch 57 into which one end of a shutter opening / closing lever 61 of a drive device is inserted into one end of a connecting plate 53 of the shutter member 5.
And the engagement piece 58 which is in contact with the tip of the shutter opening / closing lever 61 at the surface thereof, so that the distance between the upper and lower plate portions 51, 52 of the shutter member 5 is extremely small, The leading end can be reliably engaged with the shutter member 5, and there is also an advantage that the shutter member 5 can be reliably opened and closed.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of a magnetic disk cartridge according to the present invention, showing a state where a window for inserting a magnetic head is closed by a shutter member, as viewed from above.

FIG. 2 is a perspective view of the magnetic disk cartridge shown in FIG. 1, showing a state in which a window for inserting a magnetic head is opened, as viewed from a lower surface side;

FIG. 3 is an exploded perspective view of the magnetic disk cartridge shown in FIGS. 1 and 2;

FIG. 4A is a plan view of a base plate, and FIG.
(B) is a bottom view of the base plate.

FIG. 5 is a perspective view schematically showing a configuration of a shutter member.

FIG. 6 is an expanded view thereof.

7A is a plan view of the shutter member 5 with a partial cross section, FIG. 7B is a side view thereof, and FIG. 7C is a bottom view thereof.

FIG. 8 is an enlarged view of a main part showing a state where the shutter member is held at a closed position.

FIG. 9 is an enlarged view of a main part showing a state where the shutter member is moved to an open position by a shutter opening / closing lever.

FIG. 10 is an enlarged view of a main part showing a buckled state of the shutter spring when the shutter member does not have a spring holding tongue;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic disk cartridge C cartridge case 2 Base plate 3 Upper cover case 4 Lower cover case 5 Shutter member 6 Coil spring (shutter spring) 8 Case window 10 Magnetic disk media 11 Center core 12 Protective sheet 13 Cleaning member 19 Spring insertion port 21 Round Recess 23 Spring storing portion 24 Guide groove 25 Corner portion 51 Upper plate portion of shutter member 52 Upper plate portion of shutter member 53 Connecting plate portion of shutter member 54 Shutter window portion 56 Guide claw 59 Tongue piece for spring holding

Claims (1)

[Claims] 1. A flat cartridge case for rotatably accommodating a disk-shaped magnetic disk medium, a case window portion accessible to a magnetic head is formed in the cartridge case, and a shutter for opening and closing the case window portion. In a magnetic disk cartridge in which a member is slidably attached to the cartridge case in the opening and closing direction, the cartridge case is mounted on a base plate having a circular concave portion for accommodating a magnetic disk medium, and is disposed above and below the base plate. A cover case, wherein the shutter member is disposed between the base plate and the cover case, and the shutter member connects the upper surface plate portion, the lower surface plate portion, and the upper and lower surface plate portions on one side. A U-shaped cross-sectional shape formed by the connecting plate portion, and upper and lower face plate portions from the connecting plate portion A shutter window portion that is open in communication with the shutter window portion, and a cylindrical coil spring that urges the shutter member in the closing direction has one end locked to a spring receiving piece formed near an opening-side edge of the shutter window portion. A spring holding tongue which is bent from the spring receiving piece and extends substantially parallel to the connecting plate toward the opening direction of the shutter member. A magnetic disk cartridge, wherein an elongated space for accommodating the magnetic disk cartridge is provided between the magnetic disk cartridge and the connecting plate portion.