JP2001319448A - Magnetic disk cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold a center core in the center position at the time of housing and to absorb shock to a cartridge case, in a magnetic disk cartridge obtained by housing a disk-like magnetic disk medium provided with the center core in a flat cartridge case in a rotatable manner. SOLUTION: An annular part 65 is formed on the upper surface of the center core 11, and an elastic member 36 provided with a disk-like part 37 having an outer diameter smaller than the inner diameter of this part 65 at its lower end is fixed to the center position of the lower surface of an upper cover case. At the time of housing the cartridge, the part 37 of this member 36 is engaged with the inner surface of the part 65 of the center core 11 elastically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-small magnetic disk cartridge having a disk-shaped magnetic disk medium accommodated in a flat cartridge case and having a large recording capacity.

[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.

In such a conventional magnetic disk cartridge, the magnetic disk medium is fixed to the center core at the center thereof, and the bottom surface of the center core faces the outside on the lower surface of the case. A hole is formed to allow chucking of the spindle.

As the cartridge case, a synthetic resin upper and lower shell having a divided structure joined in a lid-to-lid shape is used, and further, the center core is prevented from being displaced in the radial direction due to a drop impact or the like. To this end, an annular regulating rib is provided by integral molding.

[0005] By the way, the miniaturization of the computer using the magnetic disk cartridge as described above 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.

[0006] From these points, some small personal computers have a PC card slot (PCMCIA 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 specifications of the card are type II, the thickness is 5.0 mm, and the magnetic disk cartridge and the disk drive are intended to be included in this thickness. Therefore, the thickness of the magnetic disk cartridge is about 2 to 3 mm. It must be made ultra-thin.

[0008] Even in the case of forming the above-mentioned ultra-small magnetic disk cartridge, a large recording capacity is required as a recording medium. In order to secure a maximum recording capacity by performing high-density recording, the transfer rate is increased. Therefore, it is necessary to rotate the magnetic disk medium at high speed.

The characteristics required as a large-capacity small magnetic disk cartridge include the following.

First, the cartridge case must be strong enough to suppress deformation of the cartridge case during handling such as attachment / detachment operation to the drive device or during transportation, and to ensure operational reliability. Since the temperature in the drive increases with high-speed rotation, the drive must have heat resistance to maintain rigidity and dimensional accuracy. It must be durable so that it is more frequently transported alone without being stored in a special case, so that it will not be deformed or damaged when a drop impact is applied directly. It must have dust-prevention, dust-prevention, and dust-removal functions to prevent dust, which may cause dropout, from entering from outside, and to prevent dust from being generated inside when subjected to a drop impact. Although the components are downsized, it is necessary to ensure dimensional accuracy and functional stability for ensuring stable operation, as well as secure productivity with a structure that is easy to assemble even small components.

[0011]

In consideration of the above points, it is necessary to design the basic structure of the magnetic disk cartridge. In particular, it is necessary to design the magnetic disk cartridge inside while securing the strength of the cartridge case. It is important to secure a space for accommodating the media rotatably. In other words, in the case where the upper and lower shells of the divided structure are joined in a lid-like manner like the cartridge case of the conventional magnetic disk cartridge, the thickness of the flat case becomes thin as a result of the strict regulation in the thickness direction of the cartridge case, The mechanical strength decreases. Insufficient strength of the case portion causes deformation or the like during loading or unloading operation to or from the drive device, and handling during the outside of the drive device, and the magnetic disk medium rubs against the inner surface of the case, affecting the recording / reproducing characteristics, This may cause a decrease in reliability. In addition, it is necessary that the access movement of the recording / reproducing magnetic head to the magnetic disk medium can be performed well in a narrow space.

Therefore, a base plate made of synthetic resin,
A cartridge case is constituted by a pair of metal cover cases attached to the upper and lower surfaces of the base plate, a concave portion is provided on the upper surface of the base plate, and a magnetic disk medium is rotatably accommodated in the concave portion. Conceivable.

Further, in such a cartridge case, it is impossible to form a regulating rib for positioning the center core in an annular shape by molding, so that the regulating member of the center core can be fixed to the lower surface of the upper cover case. As conceivable, if you accidentally drop the cartridge,
There is a high risk that the center core will abut against the regulating ribs provided on the cover case and be mutually damaged or deformed.

In view of such circumstances, an object of the present invention is to provide a magnetic disk cartridge having a center core restricting member having a shock absorbing function.

[0015]

SUMMARY OF THE INVENTION The present invention relates to a magnetic disk cartridge in which a disk-shaped magnetic disk medium having a center core is rotatably accommodated in a flat cartridge case. An elastic member capable of absorbing the shock to such an extent that it is practically acceptable even if it is displaced by the applied shock and comes into contact with the cartridge case is provided at the center of the cartridge case.

The above "at the time of storage" indicates a state where the magnetic disk cartridge is not mounted on the drive device.

According to one aspect of the present invention, the cartridge case comprises a base plate having an upper surface provided with a concave portion for rotatably housing a magnetic disk medium, and an upper cover case attached to the upper and lower surfaces of the base plate, respectively. And a lower cover case, wherein the center core has an annular portion on an upper surface thereof, and the elastic member has a disc-shaped portion having an outer diameter smaller than the inner diameter of the annular portion of the center core at a lower end, and the upper cover The elastic member is fixed to the lower surface of the case, and the elastic member has its disc-shaped portion engaged with the inner surface of the annular portion of the center core during storage, and the disc-shaped portion receives a force in the radial direction by the center core. It is configured to be elastically displaceable in the radial direction, and to be able to return to the original position when the force disappears.

In this case, the elastic member presses the center core elastically in the axial direction during storage and holds the center core in contact with the inner wall surface of the cartridge case. When used, the center core is rotated by the rotary drive spindle of the drive device. It is preferable that the pressing state is released so that the center core can be freely rotated.

It is preferable that a sliding member is provided on a contact surface of the disc-shaped portion of the elastic member with the spindle by, for example, sticking or coating. Further, the contact surface of the disc-shaped portion with the spindle is preferably a spherical surface that is convex in the direction of the center core.

[0020]

According to the present invention, the center portion is provided with an elastic member capable of absorbing a shock to such an extent that it can be practically used even if the center core is displaced by the shock applied to the cartridge case and abuts on the cartridge case. With this arrangement, during storage, the elastic member positions the center core at the center position, and even if the center core is displaced in the radial direction due to the impact and abuts against the cartridge case, the impact is absorbed by the elastic member. Thus, there is no possibility that the magnetic disk medium is damaged.

The cartridge case includes a base plate having an upper surface with a concave portion for rotatably storing a magnetic disk medium, and an upper cover case and a lower cover case which are respectively attached to the upper and lower surfaces of the base plate. In this case, the strength of the cartridge case in the compression direction and the bending direction can be improved, the characteristics required for the mode of use as a magnetic disk cartridge can be obtained, reliability can be secured, and good assemblability can be obtained. .

Further, the center core has an annular portion on its upper surface, and the elastic member has a disk-shaped portion having an outer diameter smaller than the inner diameter of the annular portion of the center core at a lower end, and has a lower surface of the upper cover case. The elastic member has its disk-shaped portion engaged with the inner surface of the annular portion of the center core during storage, and has a radial direction when the disk-shaped portion is subjected to a radial force by the center core. When elastically displaceable and is configured to be able to return to the original position when the force disappears, in addition to the shock absorbing effect of the elastic member during storage, the elastic member There is an advantage that the center core can always be positioned at the center position.

Further, the elastic member presses the center core elastically in its axial direction during storage to hold the center core in contact with the inner wall surface of the cartridge case. When used, the center core is rotated by the rotary drive spindle of the drive device. In a case where the pressing state is released to allow the center core to rotate freely, during storage, the center core receiving hole formed on the lower surface of the cartridge case is sealed with a flange of the center core, so that the cartridge case is closed. It is possible to prevent dust from entering the inside, and it is also possible that the elastic member does not adversely affect the rotation of the disk medium during use.

[0024]

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 an embodiment of a magnetic disk cartridge according to the present invention, showing a state in which a magnetic head insertion window 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 or the like provided with magnetic layers on both sides, and has a metal center core 11 fixedly integrated at the center.

Base plate 2 of cartridge case C
A hole 27 for accommodating an annular portion 66 (see FIG. 4) below the center core 11 is provided at the center of the center core 11.
A hole 7 having a size substantially equal to the hole is formed, and the magnetic disk medium 10 is accommodated in the cartridge case C such that the bottom surface of the hub 66 of the center core 11 faces outside from the hole 7.

At the front end of the cartridge case C with respect to the direction of insertion D (arrow in FIG. 1) into the drive device, there is formed a window 8 accessible by the recording / reproducing magnetic head. 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 such a 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.
Moreover, the adoption of the built-in shutter member 5 prevents the shutter member 5 from coming off due to insufficient strength due to miniaturization, becomes strong against dropping, etc., and has good assemblability.

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

First, the base plate 2 is made 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 circular hub accommodation hole 27 is opened at the center of the thin bottom plate of the recess 21. In addition, the front end portion of the bottom plate of the concave portion 21 is cut into a substantially rectangular shape, and the shutter member 5
Space 2 into which a lower plate 52 to be described later is movably inserted.
2, the central portion of the front end portion of the base plate 2 is removed in the front-rear direction, and the window portion 8 is opened vertically. The front surface of the front wall on one side (the right side in FIG. 3) of the window 8 of the base plate 2 is on the other side (the left 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 and have a large thickness and project 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 a shape in which the surface protrudes flush or outward with the surface of the upper and lower cover cases 3 and 4.

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 is applied, the corner portion 25 can absorb the shock, and can be inserted and inserted into the drive device. 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. The base plate 2 has a strength that allows a deformation that does not hinder the recording and reproduction of the magnetic disk medium 10. However, from the viewpoint of shock absorption, the base plate 2 is preferably made of an elastic plastic. In addition, a material containing a lubricant is preferable in terms of sliding with respect to the shutter member 5, and a material containing a filler material is used in order to improve dimensional accuracy and improve assemblability with the cover cases 3 and 4. Is good.

As shown in FIG. 1, a notch-shaped concave portion 15 is formed on the side surface of the corner portion 25 on both sides of the front portion of the base plate 2.
The concave portion 15 is provided for positioning when loaded in the drive device, or for preventing erroneous insertion in the front-back direction or the front-back direction. The recess 15 may be provided only on one side surface or on the side surface of the rear corner portion 25. In the case of the present embodiment, the corner of one of the front corners 25 is notched diagonally to form the erroneous insertion prevention part 16.

Further, on the side surface of the cartridge case C, at a position different from the concave portion 15, for example, as shown in FIG.
Although the discrimination unit 17 for disc type (for example, the type of recording capacity) is provided on the side wall of No. 4, a write protector unit may be provided here. Furthermore, the identification section 17 may be provided with an identification piece that enables the detection function to be turned on / off so as to be able to be inserted or inserted / extracted. By forming the concave portion 15 and the identification portion 17 on the side surface, a drive-side detection mechanism or the like having no installation space in the vertical direction can be arranged on the side.

The upper and lower cover cases 3, 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 are substantially symmetrical, and the four corners are rectangular. It is removed, a flat rectangular window 8 is opened in the center of the front part, and the front, rear, left and right edges are bent at right angles, and the front walls 31, 41, both side walls 32, 42,
The rear wall portions 33 and 43 are configured. The front wall portion 3 on one side (the left side in FIGS. 1 and 3 and the right side in FIG. 2) with respect to the window portion 8.
The slits 18 (see FIG. 1) are formed between the upper and lower front wall portions 31 and 41 when the upper and lower cover cases 3 and 4 are attached to the base plate 2. It has become. The shutter opening / closing member on the drive device side is inserted into the slit 18 and moves along the slit 18 to open the shutter member 5. The front walls 31 and 4 on the opposite side of the window 8 (the right side in FIGS. 1 and 3 and the left side in FIG. 2).
1, that is, a notch is formed at the end side of the portion located in front of the spring storage portion 23, and the upper and lower cover cases 3,
A rectangular spring insertion opening 19 (see FIGS. 1 and 2) is formed in a state where the front wall portions 31 and 41 of the shutter 4 are fitted together, and is used for mounting the shutter spring 6.

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. The depth of the concave portion 35 is set at the center of the space between the lower surface of the concave portion 35 facing the bottom surface of the circular concave portion 21 of the base plate 2 and the bottom surface of the circular concave portion 21 in the thickness direction of the base plate 2. 10 is set to be located. That is, the magnetic disk medium 1 located at the center in the thickness direction of the base plate 2
0 so that the upper and lower clearances are substantially equal.
By setting the depth, the rotational stability of the magnetic disk medium 10 is improved, and the presence of the concave portion 35 improves the strength of the upper cover case 3.

The upper and lower cover cases 3, 4 are provided. As shown by a symbol S in FIGS. 1 and 2,
The rear wall portions 33 and 43 and the front wall portions 31 and 41 on the side opposite to the slit 18 side with respect to the window portion 8 are integrated with the base plate 2 by performing spot welding at their contact portions. .

The shutter member 5 is inserted between the base plate 2 and the upper and lower cover cases 3 and 4 and into the sliding space 22 opened in 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, for example, formed in a substantially U-shaped cross section from a stainless steel plate or an aluminum plate. The upper plate portion 51 and the lower plate portion 52 are connected by a connecting portion 53 at the front end. The height of 53 is substantially equal to the thickness of the front part of the base plate 2. Then, a shutter window 54 is formed by being cut out in a substantially rectangular shape from the connecting portion 53 to the upper surface plate portion 51 and the lower surface plate portion 52. The shutter window 54 has a size substantially corresponding to the window 8 of the cartridge case C, and is communicated with the shutter window 54 during the opening operation. The shutter window 54 is provided at a position deviated from the center of the shutter member 5, and together with the connecting portion 53, the cartridge case C
A closing area for closing the window 8 is formed adjacent to the shutter window 54.

A spring receiving projection 55 bent from the connecting portion 53 of the shutter member 5 is provided on the inner surface of the front end of the shutter window 54 on the side of the closed area, and the shutter spring 6 formed by a coil spring in the opening and closing direction is provided on the back thereof. When contracted, the shutter member 5 is urged in the closing direction. Although not shown, at least one of the upper surface plate portion 51 and the lower surface plate portion 52 is cut and raised, and is engaged with a guide groove extending in the left and right direction on the base plate 2 so as to be assembled. It is useful for preventing the coming off. Reinforcing ribs 56 are formed on the upper plate portion 51 and the lower plate portion 52 of the shutter member 5 to prevent deformation during the opening operation. The reinforcing rib 56 is formed in a protruding shape protruding outward to suppress the generation of abrasion powder and the like due to the sliding of the tips of the upper and lower plate portions 51 and 52 contacting the upper and lower cover cases 3 and 4. It also has the effect of reducing the frictional resistance of the device and ensuring the stability of the opening and closing operation.

Above and below the magnetic disk medium 10, a protective sheet 12 made of a plastic sheet or the like having a PET sheet surface subjected to slip processing (Teflon (registered trademark) processing) is interposed. The protective sheet 12 has a portion corresponding to the window portion 8 removed in the radial direction to form a substantially C-shape, and an opening 12a is formed in a portion opposite to the window portion 8, and a cleaning member 13 is provided in this portion. The cleaning member 1 is 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.
At the same time, the protection sheet 12 is fixed by the fixation of the protective sheet 3.
The cleaning member 13 is brushed 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.

To assemble the magnetic disk cartridge 1, the protective sheet 12 is fixed to the circular concave portion 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 shutter member 5, the shutter member 5 is mounted from the front. 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. 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 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.

When the magnetic disk cartridge 1 is loaded in the drive device, the pawl of the opening / closing mechanism is inserted into the slit 18 at the front end, and engages with the end of the shutter member 5 to move it in the opening direction. Manipulate. Accordingly, the window 8 of the base plate 2 is opened, and the hub receiving hole 27 of the base plate 2 is opened.
The bottom of 1 is exposed to the outside through the hole 7 of the lower cover case,
The state shown in FIG. 2 is obtained.

FIG. 4A shows a state in which the magnetic disk cartridge 1 is mounted on a drive device (use state).
4B is an enlarged cross-sectional view showing a storage state, and FIG. 4C is an enlarged cross-sectional view showing a state in which the center core is displaced in a radial direction by an impact received in the storage state.

4 (a) and 4 (b), the center core 11 has a disc-shaped portion 62 provided at the center of a spindle hole 61 into which a spindle 70 of a drive device is inserted, and is formed above and below the disc-shaped portion 62. Annular parts 65, 66
And a flange 67 having an attachment surface 67a of the magnetic disk medium 10 on the upper surface.

A columnar elastic member 36 having an outer diameter slightly smaller than the inner diameter of the annular portion 65 above the center core 11 is vertically provided on the lower surface at the center of the upper cover case 3. Is fixed to the disk-shaped portion 37 having the same diameter as that of the disk-shaped portion 37 during storage shown in FIG.
Elastically abuts the upper surface 62 a of the disc-shaped portion 62 of the center core 11, so that the lower surface 67 b of the flange 67
Thus, in the present embodiment, the center core 11 has the annular portion 65 on the upper surface, and the elastic member 36
The upper cover case 3 includes a disc-shaped portion 37 having an outer diameter smaller than the inner diameter of the annular portion 65 of the center core 11 at the lower end.
When the magnetic disk cartridge 1 is stored, the disc-shaped portion 37 is engaged with the inner surface 62 a of the annular portion 65 of the center core 11 when the magnetic disk cartridge 1 is stored. When the center core 11 is displaced in the radial direction, the elastic member 36 is elastically bent so that this impact can be elastically absorbed, and can be returned to the original position when the force disappears. .

When the cartridge 1 is erroneously dropped in such a storage state (it is assumed that the disc medium 10 is dropped in the radial direction), the center core 11 is moved by the impact as shown in FIG.
When displaced in the radial direction as shown in (c), the elastic member 36 elastically bends and deforms to absorb the shock. Therefore, even if the outer peripheral surface of the annular ring portion 65 of the center core 11 abuts against the inner peripheral surface of the hole 27 of the base plate 2 due to this displacement, an impact is absorbed to such an extent that there is no problem in practical use. Since any further displacement is regulated by the hole 27, there is no possibility that the disk medium 10 is damaged. After the impact force has disappeared, the elastic member 36 elastically returns to the original position, so that the center core 11 is returned to the original position shown in FIG. 4B and is held at the center position.

As shown in FIGS. 4B and 4C,
In the storage state, the elastic pressure of the elastic member 36 causes
Since the lower surface 67b of the flange 67 of the center core 11 seals the hole 27 on the bottom surface of the base plate 2, it is possible to effectively prevent dust from entering through the hole 27.

Next, when the magnetic disk cartridge 1 is mounted on a drive device, as shown in FIG. 4A, when the spindle 70 is raised, the small-diameter distal end portion 71 at the center of the spindle 70 is Disc 3 at the lower end
By pushing up 7 and compressing the elastic member 36,
The center core 11 is released from being pressed by the elastic member 36, and is simultaneously pushed up to the position shown in FIG. 4A with the shoulder 70a of the spindle 70 magnetically attracted to the lower surface of the disc-shaped portion 62 of the center core 11, In this state, the center core 11 is rotationally driven by the spindle 70.

In this case, since the tip portion 71 of the spindle 70 rotates in contact with the disc-shaped portion 37 of the elastic member 36, the contact of the disc-shaped portion 37 with the tip portion 71 of the spindle 70 is reduced to reduce friction. It is preferable that a sliding member is provided on the surface by sticking, applying, or the like.

As shown in FIG. 5, the disk-shaped portion 37 of the elastic member 36 is formed in a spherical shape which is convex downward, and this spherical surface is engaged with the spindle hole 61 of the center core 11 to thereby form the elastic member 36. The function of holding the center core 11 at the center position by the position 36 can be improved.

[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 an enlarged sectional view of a main part when a magnetic disk cartridge is mounted on a drive device,
(B) is an enlarged sectional view of a main part showing a state at the time of storage,
FIG. 4C is an enlarged sectional view of a main part showing a state where the magnetic disk cartridge receives an external impact.

FIG. 5 is an enlarged sectional view corresponding to FIG. 4B, showing a modification of the elastic 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 12 Protective sheet 13 Cleaning member 19 Spring insertion opening 21 Circular recess 23 Spring storage part 25 Corner part 27 Center core accommodation hole 35 Depression 36 Elastic member 37 Disc-shaped part 61 Center core spindle hole 62 Center core disc-shaped part 65, 66 Center core annular part 67 Center core flange 70 Spindle

Claims (1)

[Claims] 1. A magnetic disk cartridge in which a disk-shaped magnetic disk medium having a center core is rotatably accommodated in a flat cartridge case, wherein the center core is displaced by an impact applied to the cartridge case during storage. A magnetic disk cartridge, wherein an elastic member capable of absorbing an impact to such an extent that it does not hinder practical use even if the cartridge case comes into contact with the cartridge case is provided at the center of the cartridge case.