JP2002050146A - Magnetic disk cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the shutter member of a magnetic disk cartridge from opening improperly. SOLUTION: An inwardly bent piece 58 is formed on one end of the linking plate part 53 of a shutter member 5 for performing the opening operation of the shutter member 5 by abutting on a shutter opening and closing lever. A locking member 60 to lock the shutter member 5 in a closed position by engaging with the bent piece 58 is fixed on the leading edge of a base plate 2.

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 cartridge for inserting a magnetic head into the cartridge case. The present invention relates to a magnetic disk cartridge in which a shutter member for opening and closing a window is slidably provided in a cartridge case.

[0002]

2. Description of the Related Art Conventionally, a magnetic disk medium (a so-called floppy disk) provided with magnetic layers on both sides of a disk-shaped base made of a flexible polyester sheet or the like is housed in a flat case, and the magnetic disk medium is stored in a flat case. A magnetic disk cartridge that performs magnetic recording on the magnetic layer by a magnetic head while rotating is provided, and is widely used mainly as a recording medium for a computer because of its advantages such as easy handling and low cost.

The cartridge case is provided with a window for inserting a magnetic head for inserting and removing a magnetic head for magnetic recording / reproduction from one side or both sides of a magnetic disk medium from the outside so as to be in contact with or close to the outside. In order to prevent intrusion of dust and the like in the above, a shutter member slidable between an open position for opening the window and a closed position for closing the window is mounted.

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 has been used. 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] From these points, some small personal computers have a PC card slot (PCMC IA specification compliant) in which a PC card is mounted for external interface and additional memory, and this PC card slot is used. 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 card is Type II and has a thickness of 5.0 mm, and the magnetic disk cartridge and the disk drive device are to be included in this thickness. Therefore, the magnetic disk cartridge has an ultra-thin thickness of about 2 mm. Must be configured.

[0007]

Even in such an ultra-thin magnetic disk cartridge, a large recording capacity is required as a recording medium. In order to increase the transfer rate, the magnetic disk medium must be moved at a high speed (2600-200).
4500 rpm).

In consideration of this point, a fundamental structure of the magnetic disk cartridge is designed. In particular, a space for rotatably housing the magnetic disk medium is secured while securing the strength of the cartridge case. Is an important issue.

That is, since the dimensional regulation in the thickness direction of the cartridge case is strict, the upper and lower shells formed by joining the upper and lower shells made of a synthetic resin having a divided structure like a cartridge case of a conventional magnetic disk cartridge in a lid-like manner. Becomes thinner, and it becomes impossible to maintain a desired mechanical strength. Insufficient strength of the cartridge case causes deformation during loading / unloading of the drive device or handling outside the drive device, and the magnetic disk media may contact the inner surface of the case, adversely affecting the recording / reproducing characteristics, and resulting in a low reliability. It may cause a decline in sex.

Therefore, a cartridge case is constituted by a base plate and a pair of cover cases attached to the upper and lower surfaces of the base plate, and a magnetic disk medium is rotatably housed in a recess formed in the upper surface of the base plate. There is a possible configuration. In this case, the shutter member for opening and closing the window for inserting the magnetic head is mounted on the base plate inside the upper and lower cover cases to secure the fitting stability.

An ultra-small magnetic disk cartridge having such a configuration is often used for mobile devices and the like, and has an advantage that it can be easily carried. On the other hand,
Because there is a high risk of exposure to external dust when carrying,
It is necessary to prevent the shutter member from being opened carelessly.

In view of the above circumstances, an object of the present invention is to provide a magnetic disk cartridge with a built-in shutter provided with means for preventing a shutter member from being opened carelessly.

[0013]

In order to achieve the above object, the present invention provides a disk-shaped magnetic disk medium rotatably housed in a flat cartridge case having a window for inserting a magnetic head. A magnetic disk cartridge comprising a shutter member slidably mounted on the cartridge case, the shutter member being opened from a closed position for closing the window by a shutter opening / closing member of the apparatus to an open position for opening the window. The case is constituted by a base plate having a concave portion for accommodating the magnetic disk medium, and a cover case respectively attached to the upper and lower surfaces of the base plate, and the shutter member connects the upper and lower face plate portions to each other at a front end. And the upper and lower cover casings. The shutter opening / closing member is mounted on the front edge of the base plate (in the direction in which the magnetic disk cartridge is inserted into the drive device) on the inside of the shutter, and the shutter opening / closing member abuts one end of the connection plate portion of the shutter member. A bent piece bent inward for opening operation is formed, and a lock member for locking the shutter member in the closed position by engagement with the bent piece is mounted on a front edge of the base plate. It is characterized by the following.

It is preferable that the bent piece is configured to abut on the shutter opening / closing member in a plane.

The lock member includes an engaging portion that engages with the bent piece, and a spring portion that resiliently biases the engaging portion toward the movement path of the bent piece of the shutter member. Is preferred.

The spring portion is connected to one end of the engagement portion, and elastically engages with a concave portion formed at the front edge of the base plate to hold the lock member at the front edge of the base plate. It is preferable that it is comprised.

The lock member includes a pressing portion which is pressed when the shutter opening / closing member is engaged with the bent piece, adjacent to a side opposite to the spring portion side of the engagement portion, It is preferable that the engagement portion is configured to be moved out of the movement path of the bent piece against the urging force of the spring portion in accordance with the pressing of the pressing portion by the shutter opening / closing member.

The engaging portion includes a locking surface facing the surface of the bent piece on the shutter opening side when the shutter member is at the closed position, and a locking surface when the shutter member returns from the open position to the closed position. And an inclined surface for moving the engaging portion out of the moving passage of the bent piece against the urging force of the spring portion by engagement with the bent piece or the shutter opening / closing member. preferable.

The lock member is formed integrally with a leaf spring material, and is configured such that the engaging portion and the pressing portion can be integrally moved as a rigid body by bending the leaf spring material. Is preferred.

[0020]

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 forming the cover case 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, and even if the cover is thin, there is no deformation such as warpage and dimensional accuracy. It is possible to maintain the characteristics, to obtain the characteristics required for the mode of use as a magnetic disk cartridge, to secure reliability, and to obtain good assemblability.

Since the shutter member is housed inside the cover case, the shutter member is prevented from being detached due to insufficient strength due to the miniaturization of the shutter member, becomes strong against impacts such as dropping, and has good assemblability. Becomes

Further, since the locking member for locking the shutter member at the closed position is mounted on the front edge of the base plate, it is possible to prevent the shutter member from being opened carelessly. Since the bent piece formed on the shutter member for opening operation is also used as an engagement portion with the lock member, the configuration of the shutter member is not complicated, and the shutter member can be downsized.

Further, the engagement portion of the lock member is engaged with the bent piece or the shutter opening / closing member when the shutter member returns from the open position to the closed position. In the case where an inclined surface is provided to move the bent piece out of the movement passage of the bent piece against the force, there is no possibility that the operation of returning the shutter member from the open position to the closed position is hindered by the lock member.

Further, since the bent piece abuts against the shutter opening / closing member of the drive device in a plane, even when the shutter member has a small thickness, a sharp edge is formed at the contact portion of the shutter opening / closing member. Since there is no danger of formation, the risk of the shutter opening / closing member being scraped by this sharp edge can be avoided.

[0026]

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

FIG. 1 shows an embodiment of a magnetic disk cartridge according to the present invention. FIG. 1 is a perspective view showing a state in which a window for inserting a magnetic head is closed by a shutter member, as viewed from above. 2 is a perspective view of the state where the window for inserting a magnetic head is opened as viewed from the lower surface side, and FIG. 3 is an exploded perspective view of the magnetic disk cartridge. 4 is an enlarged perspective view of a shutter member, FIG. 5 is a bottom view of a base plate on which a lock member is mounted, FIG. 6 is an enlarged cross-sectional view of a main part showing a state where the shutter member is locked in a closed position by the lock member, FIG. 7 is an enlarged perspective view of the lock member. 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 applied, and a center core 11 is integrally fixed to the center.

On the lower surface of the cartridge case C, the spindle of the drive motor of the drive device and the center core 11
The magnetic disk medium 10 is housed in the cartridge case C such that the bottom of the rotary drive hub 11 faces the hole 7.

A window 8 is formed at the front end of the cartridge case C with respect to the insertion direction D (arrow in FIG. 1) with respect to the drive device so that the recording / reproducing magnetic head can be accessed. The window 8 is vertically penetrated and opened from the front end surfaces 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 that opens and closes is built inside the upper and lower cover cases 3 and 4 so as to be slidable in the left-right direction.

With the above-described structure of the window 8, 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. By adopting, the shutter member 5 is prevented from coming off due to insufficient strength due to miniaturization,
It is tough against drops and the like, and the assemblability is good.

Next, the structure of each component will be specifically described with reference to FIG.

First, the base plate 2 is formed of a synthetic resin such as acrylonitrile-butadiene-styrene copolymer (ABS resin) or POM resin, and has a substantially rectangular flat plate shape. A circular recess 21 for accommodating the disk medium 10 is formed, and a center core accommodation hole 27 is opened at the center of the bottom plate of the recess 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. The window 8 which is removed and communicates with the space 22 penetrates vertically and opens. The front surface of the front wall on one side (left side in FIG. 3) of the window 8 of the base plate 2 is on the other side (right side in FIG. 3).
A spring housing 23 is formed to retreat from the front surface of the front wall, and a shutter spring 6 described later is arranged in this portion.

The corners 25 at the four corners of the base plate 2 are formed so as to protrude in the vertical direction, have a large thickness, and protrude outward. The four corners of the upper and lower cover cases 3 and 4 correspond to the corners. 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 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 25, a hole 26 penetrating in the vertical direction (a hole having an intermediate depth without penetrating) may be used.
Is provided so as to obtain a larger buffering action at the time of a drop impact. In addition, the corner of the front corner portion 25 is notched diagonally to form the erroneous insertion preventing portion 16.

The base plate 2 has such a strength as to allow deformation so as not to hinder recording and reproduction of the magnetic disk medium 10. It is preferable that the base plate 2 is made of an 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.

The upper and lower cover cases 3 and 4 are formed 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 symmetrical shape, and the four corners are rectangular. The rectangular window 8 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 and the side walls 32, 42, respectively.
The rear wall portions 33 and 43 are configured. The front wall 31 on one side of the window 8 (the left side in FIGS. 1 and 3 and the right side in FIG. 2)
41 is formed to have a low height, and the upper and lower cover cases 3 and 4
Is attached to the base plate 2, the upper and lower front wall portions 3
A slit 18 (see FIG. 1) is formed between the first and the first 41. A drive-side shutter opening / closing lever (shutter opening / closing member) 70 (see FIG. 8) is inserted into the slit 18 and moves along the slit 18 to open the shutter member 5.

Notches are formed in the front walls 31 and 41 on the opposite side of the window 8 (the right side in FIGS. 1 and 3 and the left side in FIG. 2), that is, the end side of the portion located in front of the spring housing 23. Are formed, and the front wall portions 31 and 4 of the upper and lower cover cases 3 and 4 are formed.
A rectangular spring insertion opening 19 (see FIGS. 1 and 2) is formed in a state where the shutter springs 1 are fitted together, and is used for mounting the shutter spring 6. Further, a concave portion 35 serving as a label attaching portion is formed on the upper surface of the central portion of the upper cover case 3 to improve the strength of the upper cover case 3. 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

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. . The shutter member 5 is made of metal, for example, is formed from a stainless steel plate or an aluminum plate into a substantially U-shaped cross section as shown in FIG. 4, and the upper plate 51 and the lower plate 52 are connected by a connecting plate 53 at the front end. The connecting plate portion 53 is formed so that the inner height of the connecting plate portion 53 is slightly larger than the thickness of the front portion of the base plate 2. Then, the shutter window 54 is formed by being cut out in a substantially rectangular shape from the connecting plate 53 to the upper plate 51 and the lower plate 52. This shutter window 54
Is approximately the same size as the window 8 of the cartridge case C, and is communicated with this during the opening operation. This shutter window 5
4 is provided at a position deviated from the center of the shutter member 5, and the window 8 of the cartridge case C
Is formed adjacent to the shutter window 54.

As shown in FIG. 4, a spring receiving piece 55 bent from the connecting plate 53 of the shutter member 5 is provided on the inner surface of the front end of the shutter window 54 on the closed area side. A shutter spring 6 (FIG. 3) made of a coil spring is contracted on the back of the shutter 55, so that the shutter member 5 is urged in the closing direction and is held at the closed position. In the vicinity of the connecting plate portion 53 of the lower surface plate portion 52, a guide claw 56 is formed by being cut and raised inward.

Further, the connecting plate portion 53 of the shutter member 5
A notch 57 into which the tip of a shutter opening / closing lever 70 of a drive device described later is inserted is formed at one end of the drive device. Further, an end of the notch 57 on the window 54 side is
A bent portion 58 is formed, which is bent to an inner report that comes into contact with a front end portion of the shutter opening / closing lever 70 in a plane.

On the other hand, as shown in FIG. 5, a guide claw 5 of the shutter member 5 is provided on the front edge of the lower surface of the base plate 2.
The guide groove 28 with which the guide member 6 is engaged is formed, and the notch 29 for guiding the guide claw 56 into the guide groove 28 when the shutter member 5 is mounted on the base plate 2 is formed.

As is apparent from FIG. 5, the guide groove 28 and the notch 29 are provided only on the left side of the magnetic head insertion window 8 of the base plate 2 (according to this, the shutter is not provided). The member 5 has only one guide claw 56) because of the magnetic head insertion window 8.
In the case where the guide groove 28 and the notch 29 are also provided on the right side of the shutter spring 6, when the shutter spring 6 is inserted from the spring insertion port 19, the tip of the shutter spring 6 is held by the notch 29 on the right side. This is because insertion may not be possible. The shutter member 5 includes upper and lower cover cases 3 and 4.
, The shutter member 5 does not come off the base plate 2 even if the guide groove 28 is provided only on one side.

Further, as is particularly clear from FIG. 6, the front edge of the base plate 2 has a recess 24 between the closing direction end of the operating area of the shutter member 5 and the vicinity of the notch 29.
A lock member 60 made of a leaf spring for locking the shutter member 5 to the closed position is mounted in the concave portion 24.

As shown in FIG. 7, the lock member 60 includes an engaging portion 61 which engages with the bent piece 58 of the shutter member 5, and a hairpin-shaped spring portion connected to one end of the engaging portion 61. 62, and a pressing portion 63 connected to the engaging portion 61 with a concave portion 66 on the side opposite to the spring portion 62 side.

When the shutter member 5 is in the closed position, as shown in FIG. 6, the engaging portion 61 is in the shutter opening direction (rightward direction in FIG. 6) of the bent piece 58 engaged in the concave portion 66. A locking surface 6 that faces in the shutter closing direction (left direction in FIG. 6) and is substantially perpendicular to the shutter moving direction so that the opening operation of the shutter member 5 can be prevented by closely approaching the side surface.
1a, and an inclined surface 61b facing to the upper right and formed at a position closer to the shutter opening direction side than the locking surface 61a.

The spring portion 62 is provided on the inclined surface 6 of the engagement portion 61.
1b connected to the first portion 1b and extending in the shutter opening direction
4 and a second portion 65 which is folded back from the first portion 64 to form an arch, and the second portion 65 is elastically held in the concave portion 24 formed at the front edge of the base plate 2. , The lock member 60 is mounted on the base plate 2.

The engaging portion 61 and the pressing portion 63 are made rigid so that both side edges of the lock member 60 made of a leaf spring are bent so that they can move together.
The pressing portion 63 is elastically supported in the movement path of the bent piece 58 of the shutter member 5 by the first portion 64 of the spring portion 62, and the engaging portion 61 locks the shutter member 5 in the closed position. are doing.

Referring again to FIG. 3, a protective sheet 12 made of a plastic sheet or the like obtained by subjecting the surface of a PET sheet to slipping (Teflon processing) is interposed above and below the magnetic disk medium 10. This protective sheet 12
A portion corresponding to the window 8 is removed in the radial direction to form a substantially C-shape, and an opening 12a is formed in a portion opposite to the window 8, and a cleaning member 13 is provided in this portion from the magnetic disk medium 10 side. The cleaning sheet 13 is fixed to the inner surface of the upper cover case 3 and the bottom surface of the base plate 2, and the protection sheet 12 is fixed at the same time by the fixing of the cleaning member 13. The cleaning member 13 includes the magnetic disk medium 1.
Brushed on the side facing 0, the magnetic disk medium 1
In contact with the surface of No. 0, dust on the surface is removed. An adhesive is applied to the opposite surface of the cleaning member 13.

When assembling the magnetic disk cartridge 1 having the above-described configuration, the protective sheet 12 is fixed to the circular recess 21 of the base plate 2 and the lower surface of the upper cover case 3 by fixing the cleaning member 13 in advance. After the magnetic disk medium 10 is set in the circular recess 21 of FIG. 2 and the lock member 60 is mounted in the recess 24 at the front edge of the base plate 2 as shown in FIG. It is mounted from the front so as to align with the notch 29 of the second. Subsequently, the upper cover case 3 is fitted to the base plate 2 from above and the lower cover case 4 is fitted and held from below to integrate them, and the contact portions of the upper and lower cover cases 3 and 4 are joined to each other by spot welding.

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 forms the flat space of the magnetic disk medium 10. It becomes a storage space, and the magnetic disk medium 10 is rotatably stored. Thereafter, the coiled shutter spring 6 is inserted into the internal spring accommodating portion 23 while bending the coiled shutter spring 6 from the spring insertion opening 19 in the front wall portion of the upper and lower cover cases 3, 4. , And pushed into the storage portion 23 while shrinking the rear end to complete the assembly. 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
As shown in FIG. 8A, when the shutter opening / closing lever 70 is loaded into the drive device, the front end of the shutter opening / closing lever 70 is inserted into the notch 57 at the end of the shutter member 5 through the slit 18 at the front end. It is inserted from above. With this insertion, the tip of the shutter opening / closing lever 70 is
Of the first portion 6 of the spring portion 62 to press the pressing portion 66
4 is bent downward in FIG.
8, the lock of the shutter member 5 by the engagement portion 61 of the lock member 60 is released.
Therefore, with the subsequent movement of the shutter opening / closing lever 70 to the right in FIG. 8, the shutter opening / closing lever 70 engages with the bent piece 58, and as shown in FIG. Then, the pressing portion 63 and the engaging portion 61 return to the original position by the elasticity of the first portion 64 of the spring portion 62.

When the magnetic head insertion window 8 is thus opened, the magnetic head of the drive device is inserted into the window 8 and the spindle of the drive unit engages with the center core 11 of the magnetic disk medium 10. Thus, the magnetic disk medium 10 is driven to rotate.

Next, when the magnetic disk cartridge 1 is taken out from the drive device, if the shutter opening / closing lever 70 is immediately pulled out from the notch 57 of the shutter member 5, the shutter member 5 returns to the closed position by the urging force of the shutter spring 6, and in the middle thereof, as shown in FIG.
The bent piece 58 is the inclined surface 6 of the engaging portion 61 of the lock member 60.
1b and slides on the inclined surface 61b while moving the engaging portion 61 and the pressing portion 63 downward, so that the shutter member 5 can return to the closed position shown in FIG.

Further, the shutter opening / closing lever 70 is moved as shown in FIG.
When returning from the state shown in FIG. 8B to the state shown in FIG.
The engaging member 61 engages with the inclined surface 61b, and slides on the inclined surface 61b while moving the engaging portion 61 and the pressing portion 63 downward. It can return to the closed position shown in FIG. 6 by following the urging force.

As is apparent from the above description, 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. Has a circular recess 21 having a planar shape, and the magnetic disk medium 10 is rotatably accommodated in a space defined by the circular recess 21 and the cover case 3. Attaching necessary cover parts 3 and 4 to the base plate 2 together with the cover members 3 and 4 together with the cover member 10 enables the strength of the cartridge case C to be compressed and bent in the compression direction and the bending direction while defining a medium accommodating space. Can be improved.

In particular, by forming the cover cases 3 and 4 from a high-strength material such as a metal plate, it is possible to secure the required strength as a flat case in combination with the base plate 2.
Even if the magnetic disk cartridge is thin, it is possible to maintain dimensional accuracy without deformation such as warpage, to obtain characteristics necessary for a mode of use as a magnetic disk cartridge, to secure reliability, and to obtain good assembling properties.

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 downsizing of the shutter member 5, and is resistant to impacts such as dropping. And the assemblability becomes good.

Further, since the locking member 60 for locking the shutter member 5 at the closed position is provided at the front edge of the base plate 2, it is possible to prevent the shutter member 5 from being opened carelessly. Since the bent piece 58 formed on the shutter member 5 for opening the shutter member 5 is also used as an engagement portion with the lock member 60, the configuration of the shutter member 5 is not complicated,
The shutter member 5 can be reduced in size.

The engaging portion 61 of the lock member 60 is engaged with the bent piece 58 or the shutter opening / closing lever 70 when the shutter member 5 returns from the open position to the closed position, so that the engaging portion 60 is By providing the inclined surface 61b that moves the bent piece 58 out of the movement path against the urging force of the part 62, the lock member does not hinder the operation of returning the shutter member 5 from the open position to the closed position. .

Further, as shown in FIG. 4, the shutter member 5 is formed with a bent piece 58 which comes into contact with the shutter opening / closing lever 70 of the drive device, so that the shutter member 5 has a small thickness. Even in such a case, since there is no possibility that a sharp edge is formed at the contact portion of the shutter opening / closing lever 70, it is possible to avoid a risk that the shutter opening / closing lever 70 is shaved by the sharp edge.

Further, the connecting plate 53 of the shutter member 5
A notch 57 is formed at one end of the shutter device so as to engage with the tip of the shutter opening / closing lever of the drive device, so that the distance between the upper and lower plate portions 51 and 52 of the shutter member 5 is extremely small, The distal end of the opening / closing lever 70 can be reliably engaged with the bent piece 58 of the connecting plate portion 53, whereby the opening / closing operation of the shutter member 5 can be performed reliably.

Further, the lock member 60 has its spring portion 62
Due to the elasticity of the second portion 65, the magnetic disk cartridge 1 is mounted in the recess 24 at the front edge of the base plate 2. As long as the member 60 can be held, there is no concern that the lock member 60 comes off the base plate 2.

[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. 4 is an enlarged perspective view of a shutter member.

FIG. 5 is a bottom view of a base plate on which a lock member is mounted;

FIG. 6 is an enlarged sectional view of a main part showing a state in which the shutter member is locked in a closed position by a lock member;

FIG. 7 is an enlarged perspective view of a lock member.

FIG. 8 is an enlarged cross-sectional view of a main part showing the operation of the lock member.

[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 Shutter spring 8 Magnetic head insertion window 10 Magnetic disk media 11 Center core 19 Spring insertion opening 21 Circular recess 23 Spring storing part 25 Corner part 28 Guide groove 35 Recessed portion of upper cover case 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 of shutter member 57 Notch portion of shutter member 58 Shutter member Folded piece 60 Lock member 61 Lock member engaging portion 62 Lock member spring portion 63 Lock member pressing portion 70 Shutter member opening / closing lever

Claims (1)

[Claims] 1. A disk-shaped magnetic disk medium is rotatably accommodated in a flat cartridge case having a window for inserting a magnetic head, and the window is closed from a closed position where the window is closed by a shutter opening / closing member of a drive device. A magnetic disk cartridge comprising a shutter member slidably mounted on the cartridge case, the shutter member being opened toward an open position to open the cartridge case, wherein the cartridge case has a base plate having a magnetic disk medium accommodating recess; The upper and lower cover cases respectively attached to the upper and lower surfaces of the base plate, and the shutter member is constituted by upper and lower face plate portions and a connecting plate portion connecting the face plate portions at a front end, and At the front edge of the base plate inside the cover case The shutter opening / closing member is in contact with one end of the connecting plate portion of the shutter member to form an inwardly bent piece for opening the shutter member to open the shutter member. A magnetic disk cartridge, wherein a lock member for locking the shutter member to the closed position is mounted on a front edge of the base plate.