Magnetic disc cassettes

© Start of patent period: 1963 05 15 Longest possible duration:

© Issued: 1984 01 25 © inventor:

© dependence:

AT 373 422 © Pamphlets contemplated for distinction from the prior art:

OE-OS 2551455

- 2 Nr.373422

The present invention relates to a flexible magnetic disk cartridge having a flexible magnetic disk, a center core disk mountable centrally on the flexible magnetic disk, and a flexible magnetic disk cartridge case having an upper half and a lower half, the lower half having a drive opening.

Fig.l shows a conventional on drawing and reproducing record cassette, which is provided with the reference numeral -1- and a flat cassette shell -4- contains in the form of a rectangular parallelepiped, which is composed of an upper and lower half -2 and 3-, wherein a disk-shaped, flexible magnetic disk -5- in the cassette shell -4- is rotatably received. The magnetic plate -5- is provided on both surfaces with a magnetic layer. At its center is glued with an adhesive or the like a center core disk -6- consisting of a circular plate. In the middle of Mittelkernscheibe -6- an insertion opening -7- is formed for a rotary shaft.

When the disk cartridge -1- is inserted (loaded) into a Magnot recording and / or reproducing apparatus (not shown), a tension carriage -8- enters a center opening -3a of the lower half -3-, at the same time a rotating shaft -9- in the insertion hole -7- is used for the rotary shaft. In this state, the center core row -6- is mounted on the rotating carriage -9- with a tightening member (not shown) containing a magnet. In this state, the magnetic disk -5- is centered in the direction of its thickness, considering the structure and the dimension of the cassette shell -4-. On the other hand, the magnetic head -11- is inserted into a head insertion hole -10- formed in the lower half -3- and then brought into contact with the magnetic surface of the magnetic disk -5-.

When this state of charge is reached, the center core row -6- together with the rotating carriage -9- by means of a drive, for example a motor -12-, set in rotation, whereupon the magnetic disk -5- rotates in the disk cartridge -1-. In connection with this, the magnetic head -11- is moved radially toward the magnetic disk -5- (ie, in the arrow direction a of Fig. 27), thereby performing a desired recording or reproducing operation.

In order to prevent the edge portion of the magnetic disk -5- from abutting the upper and lower halves -2 and 3, whereby it could be bent, an annular projection -13- is formed on the inner surface of the upper half -2- to prevent the displacement of the center core disk -6- relative to the cassette shell -4-. The disc cartridge is loaded with, for example, the following dimensional relationship between the cartridge case -4-, the projection -13-, the center core row -6- and the magnetic disk -5-: The thickness 11 of the cassette shell -4- is 3.4 mm, the plate thickness 12 of the upper half -2- is 0.8 mm, the plate thickness 13 of the center opening part -3a of the lower half -3- is 1.3 mm, the Projection -13- protrusion -15- is 0.5 mm, the gap -15- between the magnetic plate -5- and the projection -13- and the space -15- between the magnetic plate -5- and an annular projection -14 - on the lower half -3- is 0.4 mm each, the thickness 16 of the central core row -6- is 0.5 mm and the gap -17- between the inner surface of the upper half -2- and the Mittelkernscheihe -6- is 0.4 mm (see Fig.2). Thus, the magnetic disk -5- is arranged centrally in the direction of the thickness of the cassette shell -4-.

However, when the disc cartridge -1- is not loaded in a magnetic recording and / or reproducing apparatus, ie, when the disc cartridge -1- is not used, a gap of about 0.3 mm arises between the tip end of the protrusion -13- of the upper one Half -2- and the upper surface of the Mittelkernscheihe -6- when the magnetic disk -5- and the Mittelkernscheibe -6- move due to their own weight to the lower half -3-, as shown in phantom in Fig.2. When this gap occurs, the movement of the Mittelkernscheihe -6- from the projection -13- is no longer limited, ie the Mittelkernscheihe -6- and the magnetic disk -5- move in the cassette shell -4- freely in the horizontal direction, so that the edge portion of the magnetic disk -5- on the side wall of the cassette shell -4- can strip and is thereby bent. Once the edge portion of the magnetic disk -5- is bent, it is no longer possible to achieve a good recording and reproducing operation in the vicinity of the bent edge portion.

Such a drawback can be overcome by increasing the thickness 15 of the central core -6-, whereby the overlap length -18- between the projection -13- and the central core disk -6- when inserting the flat cassette -1 - gets bigger. However, this has not been realized because it gives rise to a very narrow gap (especially in the direction of thickness) within the cassette shell -4-, and since, as mentioned above, there is a demand that the magnetic disk -5- be in the direction of the thickness of the cassette shell -4- must be arranged centrally.

The above-mentioned disadvantage also occurs in the memory element according to DE-OS 2551455, in which a flexible magnetic disk is connected to a central core disk and housed in an axially divisible housing. In this known memory element, a relatively complicated mechanism is provided to open the memory element inserted in the recording or reproducing device in order to be able to introduce a scanning head into the memory element. This mechanism also requires a relatively large height, whereby a correspondingly large storage space is required for the storage element.

The aim of the invention is to propose a flexible magnetic disk cartridge of the type mentioned, in which the above disadvantages are avoided. In particular, even if the disk cartridge is not in operation, the movement of the center core disk and thus the magnetic disk should be restricted to a predetermined range.

According to the invention this is achieved in that the central core disc has a raised edge whose outer diameter is greater than the diameter of the drive opening, and that a central hollow body part of the central core disc is arranged loosely in the drive opening.

This ensures that the central core disc is movable in the radial direction only by the amount of play between its inner cylindrical surface and the outer diameter of the central hollow body part and axially only to the reduced by the strength of the raised edge of the central core disc and the magnetic disk clear height of the cassette ,

According to a further feature of the invention it is provided that the central hollow body part of the central core disc is formed for receiving an annular, formed on the inside of the upper half of the shell projection, said projection is formed with such a longitudinal extent that it into the drive opening of the lower half of the casing is sufficient. In this way, a further restriction of the axial play of the center core disk can be achieved.

Other features and advantages of the invention will become apparent from the following detailed description of an exemplary embodiment and the drawings in which: Fig. 1 is a longitudinal sectional view schematically showing a conventional disc cartridge which is incorporated in a magnetic recording and / or recording medium Playback device has been inserted; Figure 2 shows the enlarged section along the axis II-II of Fig.l; Fig. 3 is an exploded perspective view of a flexible disk cartridge according to the embodiment of the invention; Figure 4 shows the oblique view of an upper half of a cassette shell seen from below; Figure 5 is a plan view of a central core disc, seen from a recessed side; Fig. 6 shows the oblique view of a disc cartridge seen from below; 7 shows the longitudinal section through a main part of the disk cartridge, wherein the middle part is shown and parts have been omitted. Fig. 8 is a longitudinal sectional view of a main part of the disc cartridge, showing a guide including a guide groove formed in the cartridge case and a latch-like projection formed on a shutter; Figures 9 and 10 are each a longitudinal section through a main part of the disc cartridge in which a variety of the guide is shown; FIG. 11 the longitudinal section through a main part of the disc cartridge, wherein on the cassette shell a pawl is formed to prevent accidental erasure; Fig. 12 is an exploded perspective view showing the disc cartridge and a main part of a recording and / or reproducing apparatus according to the embodiment of the invention into which the disc cartridge is to be inserted; Fig. 13 is a plan view of the above-mentioned apparatus with the cassette pressing member removed; FIG. 14 the plan of the device with the Kassettenandruckteil; Fig. 15 is a section along the axis XV-XV of Fig. 14; Fig. 16 is a section along the axis XVI-XVI of Fig. 14; FIG. 17 shows the section along the axis XVII-XVII of FIG. 14; FIG. Fig. 18 is an exploded perspective view showing the rotor of a motor, a spacer, a leaf spring to which the spring-biased drive pin is fixed, a yoke, and a motor housing in an assembled state; FIG. 19 the section along the Ach- 4 Nr.373422 se XIX-XIX of Figure 13; Figures 20 and 21 of Figure 19 similar sections, in which the operation of the spring-biased drive pin is shown. FIG. 22 the exploded perspective of a major part of the head moving means; FIG. 23 shows the oblique view of a rotary position detector for the motor shaft of a stepping motor; FIG. Eig.24 the section along the axis XXIV-XXIV of Fig.22; Fig. 25 shows the section along the axis XXV-XXV of Fig. 24; Fig. 26 is a longitudinal sectional view of a main part showing the cooperation between the pawl which prevents erroneous erasure of the disc cartridge and a ratchet scanning member which prevents erroneous erasure; Fig. 27 is a simplified side elevation showing the principle of correction against internal discarding of the upper and lower plates of the cassette shell; FIG. 28 the plan view of the central core disc in a state of charge, wherein the motor shaft and the spring-biased drive pin are respectively inserted into the Motorwelleneinsetzöffnung and the insertion hole for the spring biased drive pin, both of which are formed in the central core disc.

An embodiment of the invention will now be described with reference to FIGS.

In this embodiment, a flexible magnetic disk cartridge containing a disc-shaped flexible magnetic disk is set in a recording and / or reproducing apparatus, and a recording and / or reproducing operation is performed. First, a disk cartridge -26- containing a flexible magnetic disk -21 and a disk cartridge -22- will be explained. As shown in FIG. 3, the flexible magnetic plate -21- is constructed, for example, from a thin, disc-shaped, high-polymer layer having a thickness of 0.4 mm, a uniform magnetic layer being formed on both surfaces, with which a recording / reproducing Magnetic head is brought into contact. In the center of the flexible magnetic plate -21- is a circular center opening -21a- (s. 7), to which a central core disc -23- made of ferromagnetic material, such as iron, is attached. The central core disc -23- is pressed from a flat disc, wherein, as shown in Figures 3 and 7, on one side a central cavity -23a- and on the other side a disc-shaped, convex part -23b- are formed, while at the edge part of the Mittelkernscheibe -23- an annular raised edge -23- is formed. The Mittelkernscheibe -23- is thus built pan-shaped. As shown in Fig. 7, attached to the raised edge -23c of the center core disk -23- is an annular, double-sided adhesive plate -27- with the peripheral portion of the central aperture -21a of the magnetic disk -21- attached to the double-sided adhesive sheet -27 - Is glued, whereby the central core disc -23- and the flexible magnetic plate -21- are interconnected.

In the vicinity of the center part of the center core disk -23-, there is formed a quadrangular center opening -24- serving as an insertion hole for the motor shaft. At a position spaced apart from the center opening -24- by a predetermined distance, there is formed a rectangular drive and adjustment hole -25- which serves as an insertion hole for the adjustment pin. As can be seen clearly from FIG. 5, the center 01 of the center opening -24- is displaced from the center 02 of the center core disk -23- and the flexible magnetic disk -21- and slightly displaced by a predetermined distance in the direction of the drive and adjustment opening. added. The center opening -24- and the drive and Einstellöffnung -25- are formed so that two diagonals dl and d2 of the central opening -24- to the short or long side panels -25b and 25a- the drive and adjustment hole -25- are parallel. Furthermore, the length from one side of the central opening -24- is slightly larger than the diameter of the motor shaft, so that the motor shaft when playing in the central opening -24- has some play. The reason why the center of the central opening -24- is somewhat offset from the center of the central core disk -23- is, as will be described later in detail, to coincide with the center of the motor shaft when in the center opening -24 The center core disk -23- is fixed in the center of the flexible magnetic disk -21- when the disk cartridge -26- has been inserted into the recording and / or reproducing apparatus.

On the other hand, as shown in Fig. 3, the cassette shell -22- accommodating the flexible magnetic plate -21- is constructed of upper half -22a and lower half -22b which are made of an ABS resin by injection molding, for example to which an anti-static agent was added. The outer edge portions of the upper and lower halves -22a and 22b- are welded together to form a flat, rectangular cassette. In the vicinity of the central part of the lower half -22b-, a circular opening -28- is formed as a drive opening, wherein at the edge portion of the drive opening -28- and on the inner surface of the lower half -22b- together an annular projection -29- is formed. As shown in Figs. 6 and 7, the convex part -23b- of the center core disk -23- is inserted into the drive hole -28- so as to have some play. On the inner surface of the middle part of the upper half -22a, as shown in Figures 4 and 7, together an annular projection -30- is formed. Also around the projection -30- an annular projection -31- is formed which is concentric with the projection -30-. The projection of the projection -30- is longer than that of the projection -31-, whereby, as shown in Figure 7, the projection -30-- extends beyond the projection -31- and into the inner surface of the lower half -22b- projects. The annular projection -30- is inserted into the central cavity -23a of the central core disk -23-- so that it has some play on.

The cassette housing -22-, the upper and lower halves -22a and 22b-, the central core opening -23- and the annular projection -30- of the upper half -22a have, for example, the following dimensions: The thickness Ll of the cassette case -22- is 3.4 mm, the thickness L2 of a top plate -22c- and a bottom plate -22d- of the top and bottom halves -22a and 22b- are each 0.8 mm, the thickness L3 the upper plate -22c- of the upper half -22a of the part which the projection -30- surrounds is 1.0 mm, the projection L4 of the projection -30- is 1.5 mm, the thickness L5 of the central core disk -23 - is 0.3 mm, the thickness L6 of the lower plate -22d- of the lower half -22b- adjacent to the central opening -28- is 1.3 mm, and the height L7 of the central core disk -23- is 1.8 mm (see Fig. 7).

When the disc cartridge -26- is inserted into the recording and / or reproducing apparatus, as will be described later, the flexible magnetic disc -21- is disposed almost centrally in the direction of the thickness of the cartridge case -22-, as shown in FIG is shown with solid lines, whereupon it is rotated. In this case, the distance L8 between the edge -23c- of the center core disk -23- and the inner surface of the upper half -22a and the distance L9 between the flexible magnetic disk -21- and the projection -29- of the lower half -22b is - each 0.4 mm. The distance L10 between the spigot end of the protrusion -30- of the upper half -22a and a lower face -23d- of the central core disc -23- is 0.4 mm and the distance Lll between the outer surface of the lower half -22b- and the lower one Area -23d- of the center core disk -23- is 0.2 mm (see Fig. 7). When the disk cartridge -26- is not used, the center core disk -23- and the flexible magnetic disk -21- are arranged on the lower half -22b- due to their own weight, for example, as shown in phantom in FIG. In this case, the tip end portion of the upper half projection -30- and the lower half projection -29b -22b- are overlapped by 0.4 mm (pitch L12), so that even if the center core disk -23 - Is moved, a part of the central cavity -23- the central core disc -23- securely engages the projection -30-. The clearance in the plane direction of the center core disk -23- and thus the flexible magnetic disk -21- is kept within a predetermined range, so that the projection -30- and the center cavity -23a- the central core disk -23- upon displacement of the central core disk -23 - Do not disengage. When the disc cartridge -26- is turned upside down from the position shown in Fig. 7, and therefore the center core pulley -23- comes to rest on the upper half -22a- due to its own weight, the projection -30- completely fits in the center lumen -23- the center core disk -23-, so that, as in the above-mentioned case, a displacement of the center core disk -23- and thus the magnetic disk -21- is kept within a predetermined range.

In the disk cartridge -26- constructed as described above, displacement of the center core disk -23- and thus the flexible magnetic disk -21- with the projection -30- can be accurately adjusted until the gap between the upper and lower disks lower plate -22c and

22d- larger than 2.2 mm (the sum of the overlaps of 0.4 mm and the central core disk height of 1.8 mm), while the upper and lower halves -22a and 22b- from that in Fig.7

- 6 Nr.373422 state, ie, in the direction in which the upper plate -22c and the lower plate -22d- move away from each other.

On the inner surface of the upper and lower halves -22a and 22b-, four arcuate ribs -33 and 34- are formed collectively, which extend concentrically with the driving opening -28- at 5 regular intervals. When the cassette shell -22- is assembled, the ribs -33- of the upper half -22a and the ribs -34- of the lower half -22b- are arranged on the same circumference, at the same time the ribs -33 and 34- side by side to the four corners of the cassette shell come to rest, whereby in each corner substantially a pair of ribs is formed. The flexible magnetic plate -21- is arranged so that it is surrounded by 10 of these ribs -33 and 34-. The ribs -33- lie on the inner surface of the lower plate -22d- of the lower half -22b- and the ribs -34- on the inner surface of the upper plate -22c- of the upper half -22a-. Thereby, the cassette shell -22-, which is flat and can be deformed by a small external force, is mechanically reinforced. In order to prevent possible damage or wear of the flexible magnetic plate -21- 15 is further between the projection -31- and the ribs -33- and between the projection -29- and the ribs -34- in the upper and lower half - 22a and 22b - a nonwoven fabric or the like. welded.

The distance from the center of the drive hole -28- of the lower half -22b- to the ribs -33 and 34- is slightly larger than the radius of the flexible magnetic plate -21-, so that even if the flexible magnetic plate -21- in the cassette shell -22- is displaced by the play of the center core plate -23- in the drive hole -28-, the edge part of the flexible magnetic plate -21- does not abut against the ribs -33 and 34-.

In the upper and lower halves -22a and 22b- of the cassette shell -22- and in the nonwoven fabric -35- openings -36, 37 and 38- are respectively formed, which have the same shape 25 and in the radial direction of the flexible magnetic plate -21 - extend. The openings -36, 37 and 38- are overlapping each other. As will be shown later, a magnetic head is inserted from the opening -37- formed in the lower half -22b- through the opening in the lower nonwoven fabric -35-, while from the opening -36-, in the upper half Is formed through the opening -38- in the upper nonwoven fabric -35- a head pressure pad 3θ is used. In Fig. 3, reference numerals -39a and 39h denote adjusting protrusions which engage in each other in assembling the upper and lower halves -22a and 22b.

As shown in Figs. 3 and 6, in each outer surface of the upper and lower halves -22a and 22b-, a recess -40- is formed in those portions where the cushion insertion hole -36- and the head insertion hole -37- are formed. In the recess -40- a Ver35 end -41- is attached, which has a U-shaped cross-section and made of aluminum, stainless steel, synthetic resin od.ähnl. is set forth so that it can slide in a predetermined direction. In the recess -40- of the lower half -22b-, as shown in Fig. 6, a straight-line guide groove -42- is formed which extends along a side edge of the cassette shell -22-. As shown in FIG. 8, in the shutter 41, in connection with the guide groove 42, a clinically shaped projection 43 is formed, for example, at three locations by a part of the shutter 41 with the aid of a pressing operation. similar. is bent inwards. The pawl-like projection -43- of the shutter -41- is inserted into the guide groove -42- of the lower half -22b- so that the shutter -41- is guided by the guide groove -42- so as to be movable in the arrow directions A and B of Figure 6 can slide. The sliding device for the Ver⁴⁵ The conclusion is not limited to the above description. For example, as shown in Fig. 9, a part of the shutter -41- may be replaced with a press or the like. half punched out to form a projection -44a, which extends into the interior of the closure. The projection -44a is thereby slidably received in the guide groove -42-. As shown in Fig. 10 further, a V-shaped projection 44b may be formed which extends inwardly into the shutter⁵⁰ -41-, wherein this projection -44b- is slidably received in the guide groove -42-.

On the side edge of the lower half -22b-, where the guide groove -42- is formed (see Fig. 6), there is a lock mounting and dismounting recess -56- which is in line with the guide 7 - No.373422 groove - 42- is connected, for example, formed in three places. When the shutter -41- is shifted, for example, in the direction of arrow B of Figure 6 in the dot-dashed position, the recess -56- and the latch -like projection -43- of the closure -41- are opposite each other. When a tension is exerted on the shutter 414 of the cassette 42 in this state, the shutter 41 can be easily detached from the cassette shell 22.

In each of the opposite plate parts -41a and 41b- of the shutter -41-, an opening -45- is formed, which has substantially the same shape as the pad and Kopfeinsetzöffnung -36 and 37-. By moving the closure -41- along the guide groove -42- the pad and head insert openings -36 and 37- can optionally be opened or closed. When the shutter -41- is arranged as shown in Figure 6 with solid lines, the opening -45- overlap in the shutter -41- and the openings -36 and 37- in the cassette shell -22-, ie the openings - 36 and 37- are open. On the other hand, if the closure 41 slides into a position which is shown in phantom in FIG. 6, the openings 36 and 37 are covered and closed with the closure 41.

On the side part of the cassette shell -22-, to which the closure -41- is attached, as shown in Figures 3 and 6 show, a recess -53- is formed. This recess -53- is opened or closed by the above-described displacement of the closure -41-. Therefore, when the opening -45- in the shutter -41-, the openings -36 and 37- in the cassette shell -22- and the opening -38- in the nonwoven fabric -35- overlap, the recess -53- is opened. However, if the openings -36, 37 and 38- covered with the closure -41-, also the recess -53- is closed. When the recess -53- is opened, as will be described later, the cassette shell -22- can be inserted in the recording and / or reproducing apparatus in the correct position, so that a recording and playback operation can be made. However, if the recess -53- is closed with the shutter -41-, as will be shown later, the disc cartridge -26- in the device can not be placed in the normal working position, so that a malfunction is prevented.

Further, to prevent wrong insertion of the cassette shell -22-, a triangular recess -52- is formed at a predetermined corner of the cassette shell -22-.

Further, in this embodiment, means are provided at a corner of the cassette -22- to prevent erroneous erasure so that the information recorded on the flexible magnetic disk -21- can not be erased by mistake. As shown in Figs. 3 and 11, a channel-shaped recess 46 is provided at a given corner of the lower half 22b of the cassette shell 22, and within the recess 46, there is a catch 47 which causes erroneous deletion prevented, with the lower half -22b- connected by a weak point -49-, which is formed by a V-shaped groove -48-. On the inner surface of the free end of the catch -47- is formed a support -50- extending to the upper plate -22c- the upper half -22-, wherein the free end of the support -50- the inner surface of the upper plate - 22c touched. Therefore, even if a pressing force is applied in the arrow direction C of Fig. 11, the catch -47- which prevents erroneous erasure is not separated from the lower half -22b-. However, if it is desired that the detent -47- be disconnected from the lower half -22b- to prevent erroneous cancellation, one can apply a rotational force in the direction of arrow D of Fig. 11 to the free end of the detent -47- , whereby the weak point -49- can be easily broken off to bend the catch -47-. The reason for such a construction is that the thin cassette shell has limitations in thickness when the latch 47 is to be pushed inward and bent. By the structure according to this embodiment, it is possible to bend the catch -47- accurately and easily.

At the two corner portions on the side of the opening -37- of the lower half -22b- and in positions outside the ribs -34-, two adjusting holes -51- are provided to adjust the cassette shell -22- when the disk cartridge -26- in which is loaded on a drawing and / or reproducing device. In this embodiment, automatic loading recesses -54 and 55- are also provided on both sides of the cassette shell -22- having a semicircular cross-section. In the recesses -54 and 55- are two support rods (not

No. 8343422) to a predetermined transport means to hold the cassette shell and automatically move it to a predetermined position, if necessary. By the use of the automatic loading recesses -54 and 55- it becomes possible to construct a device so that an automatic change of the disc cartridge -26- and an automatic cartridge unloading operation can be performed in a quality control.

In connection with Figs. 12 to 28, the construction of the recording and / or reproducing apparatus into which the disc cartridge -26- is to be inserted will now be described.

As shown in FIGS. 12 to 14, on a chassis of a recording and / or reproducing apparatus (hereinafter referred to simply as a device), four cassette receiving pins -63, 64, 65 and 66- are attached to the disk cartridge. 26- record. Among these pins, there are provided at the upper ends of the two pins -63 and 64- formed cassette adjusting protrusions -67 and 68-, respectively, which fit into the two adjusting holes -51- shown in Figs

Cassette shell -22- are formed. The cartridge receiving pins -63, 64, 65 and 66- are provided at their upper ends with receiving surfaces -63a, 64a, 65a and 66a, respectively, which are equal in height with respect to the chassis -61-. On the chassis -61- are attached two L-shaped support members -69 and 70-, to which a pivot pin -73 or 74- a Kassettenandruckteil -72- is mounted. The cassette pressing member 72 has a plate body 72a, with four cassette pushing pins -75, 76, 77 and 78- fixed to the lower surface of the plate body 72a. As shown in Figs. 15 to 17, these pins -75 to 78- are slidably supported vertically in a sleeve -79- provided in the plate body -72a. At the same time, these pins -75 to 78- are normally biased downwardly by a helical compression spring -81- which lies between the sleeve -79- and a spring shoe -80-. Thus, the disc cartridge -26- is pushed by the cartridge pushing pins -75, 76, 77 and 78- against the cartridge receiving pins -63, 64, 65 and 66- to hold them.

As seen from Fig. 14, in this embodiment, the disc cartridge -26- is picked up at its four corners by the cartridge receiving pins -63, 64, 65 and 66-. On the other hand, the positions at which the cartridge pushing pins -75, 76, 77 and 78- of the cartridge pushing member -72- hold down the disc cartridge -26- by a predetermined distance from the positions of the pins -63, 64, 65 and 66- to the center the disk cartridge -26- offset. That is, the cartridge pushing pens -75 and 77- are disposed near a straight line connecting the cartridge receiving pins -63 and 65-. Furthermore, the cassette pressure pins -75 and. 77- between these pins -63 and 65- and are constructed to cooperate with the ribs -33 and 34- of the disc cartridge -26-. The cassette pushing pins -76 and 78- as well as the cassette receiving pins -64 and 66- are also arranged in the above described relationship.

On the chassis -61- is further fixed a drive -82- to rotate the flexible magnetic disk -21- in the disk cartridge -26- in rotation. Almost in the middle of the part enclosed by the cartridge receiving pins -63, 64, 65 and 66- is mounted a brushless flat motor -83- to rotate the flexible magnetic disk -21- in the disk cartridge -26-. As Fig. 18 4, on the upper surface of a rotor 83a of the motor 83, there are a spacer -84- which has the shape of a partially cut-out annular disc, a leaf spring member 86 on which a spring-biased drive pin -85- for the setting (centering) of the flexible magnetic plate -21- is mounted in the cassette shell -22-, and a disk-shaped yoke -90- having an annular recess -88- formed in the upper surface, connected with two fixing screws -91-. The leaf spring member -86- is located between the spacer -84- and the yoke -90-, wherein the spacer -84-, the leaf spring member -86- and the yoke -90- further connected to a fastening screw -92-, so that these components are rotated together with a motor shaft -83b- of the motor -83-.

As shown in Fig. 18, a generally horseshoe-shaped opening -94- is formed almost in the middle of the leaf spring portion -86-. Further, a pin fixing part -96- is formed together with two narrow L-shaped arm parts -95- with the pin fixing part -96- held on both sides by the two arm parts -95-. The drive pin -85- is on pin number 377222

- 9 fixing part -96- attached. As Fig. 19 21 to 21, the resiliently biased drive pin -85- is made of a shaft portion -98- having a nearly centrally disposed flange -98a, a bearing portion -99- which fits and secures to the upper end of the shaft portion -98- is, and a cylindrical part -101- built, which can rotate with respect to the shaft part -98- by means of a ball bearing -100-, which lies between the bearing part -99- and the cylindrical part -101-. The shaft portion -98- extends through the pin attachment portion -96-, with a cylindrical attachment portion -102- attached to the lower end of the elongate portion of the shaft portion -98-. The flange -98a of the shaft portion -98- and the mounting portion -102- holds the pin mounting portion -96- of the leaf spring portion -86- in position, whereby the resiliently biased drive pin -85- is secured to the pin mounting portion -96-. The pin -85- is arranged so that the cylindrical portion -101- of the pin -85- passes through a hole -89-, which recess in the recess -88- of the yoke -90- is formed. Thereby, the pin -85- in the hole -89- in the direction of arrow E of Fig. 19 by the elasticity of the leaf spring part -86- moves and partially pivoted in the direction of the arrows F and G, whose center on the arm portion -95- of FIG. 19 is (in other words: it is in the radial direction of the yoke -90-) movable. The pin -85- is fixed so that the distance -SI- of Fig.19 is slightly longer than the distance -S2- of Fig.28.

An end portion -83c- of the motor shaft -83b- of the motor -83- is generally hemispherical, with the highest point of the end portion -83c- of the motor shaft -83b- set at a predetermined level. As will be shown later, the end portion -83c- engages the inner surface of the upper plate -22c- to correct an inward warping of this plate when the upper plate -22c- of the cassette shell -22- to the lower plate -22d- discards when the disc cartridge -26- is inserted in the device -60-. ·

On the other hand, in the recess -88- of the yoke -90-, four pairs of magnets -104- are adhered at approximately equal intervals in the circumferential direction or fastened in a similar manner. On the upper surfaces of the inner and outer flanges -90a, 90b- of the yoke -90- are each glued to the film -105, 106-, the Teflon film od.ähnl. exist and contain carbon. As shown in Figs. 19 to 21, the upper surfaces of the lubricating sheets -105 and 106- [ie the receiving surfaces for the central core disc (23)] arranged so that they are aligned with each other and above the upper surfaces of the magnets -104- lie. The cylindrical portion -101- of the pin -85- protrudes upward from the upper surface of the lubricating sheets -105 and 106-.

In Figs. 12 and 13, reference numeral -107- denotes a motor housing, on the lower surface of which is formed an opening -107a. In this hole -107a, the yoke -90- is rotatably disposed, and the lubricating sheets -105 and 106- stuck to the yoke -90- project upward from the upper surface of the motor housing -107-.

Now, a head movement stage in the device -60- will be described.

The head movement stage has a head mount -110- to which a magnetic head -108- is mounted on a mounting plate -109- and a feed spindle -112- which is driven about its axis by a stepping motor -111-. As shown in Figs. 12 to 14, the stepper motor -111- is screwed to a vertical portion -113- of the chassis -61-, with a motor shaft -lila- of the stepping motor -111- being directly connected to the feed spindle -112-. The other end of the feed spindle -112- is rotatably received in a cut-out portion -117- of the chassis -61-, with the feed spindle -112- to the chassis -61- arranged horizontally.

In this embodiment, the headgear -110- is constructed so that it can move along the axis of the feed spindle -112-. For this purpose, two guide axle fastening parts -114, 115- are provided on the chassis -61-, the two end parts of a guide shaft -116-, which have no circular cross-section, being attached to the fastening parts -114 and 115-. The guide shaft -116-, which is parallel to the feed spindle -112- extends through the head support -110- and is mounted in this position in a sleeve -118-, which is attached to the head holder -110-. As a result, the headgear -110- can slide in the direction S and T of FIGS. 12 and 24 in arrow 10 No. 373422 while being guided by the guide shaft -116-.

As shown in FIGS. 12 and 22, together with the head support 110-, two attachment parts 120- are formed for a needle-shaped part which are opposed to each other at a distance. The feed spindle -112- extends through an opening -121- which is formed in the vertical part -113- of the head holder -110-, and lies between the two attachment parts -120- for the needle-shaped part. In the upper surface of the two fasteners -120- are V-shaped grooves -122a or 122b-, these V-shaped grooves -122a and 122b- having an inclination corresponding to the pitch of the threaded portion of the feed spindle -112- perpendicular to the axis of the feed spindle -112- and extending on the same straight line. Between the two fastening parts -120- extends a needle-shaped part -124-, whose ends are inserted into the V-shaped grooves -122a and 122b-. As shown in Figure 24, it is further without play between and longitudinally adjacent threads (ie the reason) of the feed spindle -112- used. Above the needle-shaped part -124- is disposed a retaining plate -125- which is attached to the upper surfaces of the fastening parts -120- with two fastening screws -126-, whereby the needle-shaped part -124- is attached to the fastening parts -120- thus as described above. As shown in Fig. 25, a leaf spring -127- is further attached to the lower surface of a fixing member -120- with the adjusting screw -126-, and by the spring restoring force of the free end of the leaf spring -127- the feed screw -112- is normally against the needle-shaped part -124- and the retaining plate -125- is pressed. As a result, the needle-shaped part -124- and the threaded part of the feed spindle -112- never disengage apart and the needle-shaped part -124- remains engaged with no play between adjacent threads.

As shown in Figures 12 and 24, a pad attachment portion -129- is pivotally mounted to the headgear -110- carrying a pad -128- which is made of felt or the like. is made. More specifically, attached to headgear -110- are two opposing vertical parts -130- which extend perpendicular to chassis 61-, with each of these vertical parts -130- being fitted with a bearing -131- (see Figs. 12 and 13). Further, in the bearings -131- pivots -132- are mounted, which are attached to the pad fastening part -129-, while between a vertical part -130- and the head mount -110- extends a helical compression spring -133-. As a result, the headgear -110- is normally urged about the pivots -132- in the direction of arrow H of Figs. 12 and 24, ie in the direction in which the pad -128- presses on the magnetic head -108-. When the disc cartridge -26- is not inserted in the device -60-, the head support -110- in the direction of arrow 1 of Figure 12 against the force of the helical compression spring -133- by means of a predetermined biasing means, such as a Tauchkernspule (not shown), biased so that the pad -128- from the magnetic head -108- spaced. This means that the in Fig. 12 shown state of the device -60- is the state in which the disk cartridge -26- is not inserted or not in operation. When the disc cartridge -26- has been inserted or is in operation, the head holder -110- is pivoted in the direction of arrow H by means of the force of the helical compression spring -133-. As shown in Fig. 24, the magnetic plate -21- exposed in the holes -36 and 37- in the cassette shell -22- is thereby held between the pad -128 and the magnetic head -108-.

In Fig.23, a disk -135- made of synthetic resin od.ähnl. is attached to the other end of the motor shaft -lila- of the stepping motor -111-, with a reflector -136- attached to a part of the lateral surface of the disc -135-. On the other hand, a detector -137- which consists of a light-emitting component and a photosensitive component (photocell), arranged opposite the outer surface of the disc -135-. By means of the detector -137- and the reflector -136-, a rotational position of the motor shaft -lila- of the stepping motor -111- is scanned. Near both ends of the feed spindle -112-, a scanner -137a is mounted to sense a moving position of the head holder -110- with respect to the feed spindle -112-. Based on the scanning signals of this scanning device -137a and the detector -137-, the start and end positions for the rotation of the motor shaft -lila- are set, as will be described later. This allows the magnetic head

- 11 Nr.373422 -108- are moved, with only a movement amount is required to record with the magnetic head -108- on the magnetic disk -21- or from the magnetic disk -21- to play (ie within a predetermined range of motion). Denoted at -138- in Fig. 12 is an optical pulse generator for sampling a rotational phase of the brushless flat motor -83-.

As shown in Figs. 12 and 26, on the cassette receiving pin -65-, a scanning member -140- is mounted so as to be movable along the axis of the pin -65- to prevent erroneous erasure. The scanning part -140- is provided at one end with an upward scanner -143-. The sensing member -140- is normally urged upward by a helical compression spring -141- and held by a stop -142- which is secured to the upper end of the pin -65-. On the other hand, a detector -144- is mounted on the chassis -61- in which a light-emitting device and a light-receiving device (both not shown) are opposed to each other. The detector -144- is constructed so that upon a downward movement of the scanning part -140- the other end of the scanning part -140- can slide between the light-emitting and the light-receiving device. Therefore, while the scanning member -140- is held by the helical compression spring -141- at the stop -142-, the other end of the sensing portion -140- is upwardly spaced so that it does not lie between the light-emitting and the light-receiving device. When the scanner -143- of the scanning part -140- of the latch -47- which prevents erroneous erasure is pressed down the cartridge -22-, the other end of the scanning part -140- comes between the light-emitting and light-receiving devices against the force of the helical compression spring -141-, thereby performing the recording operation in the above case. Otherwise, a recording operation is prevented.

In this embodiment, to prevent misplacement (loading) of the disc cartridge -26- into the device -60-, protrusions -146 and 147- which prevent mis-insertion on the chassis -61- are opposite the channel-shaped recess -53- and the triangular recess -52- formed respectively in the disc cartridge -26-.

The operation of the device -60- having the structure described above will now be described.

First, the shutter -41- of the disc cartridge -26- to be inserted into the apparatus -60- is shifted in the arrow direction A of Fig. 6 until the holes -36 and 37- of the disc cartridge -26- and the disc holders -26- are inserted Opening -45- of the shutter -41- overlap each other, whereby the openings -36 and 37- and simultaneously the channel-shaped recess -53- the disk cartridge -26- are opened. Thereafter, the disc cartridge -26- is inserted into the apparatus -60- by means of the cartridge loading device, not shown. As shown in Fig. 14, in this case, the protrusions -146 and 147- of the chassis -61- which prevent improper charging can enter the channel-shaped recess -53- and the triangular recess -52- of the disk cartridge -56-, so that the cassette shell -22- can be placed in the normal loading position. The disc cartridge -26- is placed on the cartridge receiving pins -63, 64, 65 and 66- of the cartridge loading device. In this case, the protrusions -67 and 68- of the cartridge receiving pins -63 and 64- respectively fit into the adjusting holes -51 and 52- formed in the cartridge case -22-, whereby adjustment of the disc cartridge -26- in the plane direction, ie longitudinal and transverse direction, is performed. Simultaneously, the cassette pushing member -72- is pivoted about the pivots -73 and 74- into locking with the cassette loading means whereby the pins -75, 76, 77 and 78- of the cassette pushing member -72- elastically pushes the disc cartridge against the force of the helical compression springs. press down. As a result, the disc cartridge -26- between the pins -63, 64, 65 and 66- and the pins -75, 76, 77 and 78- of the pressing portion -72- elastically held, whereby the adjustment of the disc cartridge -26- in terms of their height is carried out.

When inserting the disc cartridge -26- the recess -53- is covered with the shutter -41-, or the triangular recess -52- not in the normal position (ie

If the loading direction of the disc cartridge -26- is not correct), the disc cartridge -26- is not placed in the above normal loading position, because the corner parts of the deck 12 are in the normal loading position

Nr.373422

Butt the disk -26- against the projections -146 and 147-. As a result, the charging operation described above is not performed and recording and reproduction can not be performed. Therefore, it is under no circumstances possible that the magnetic head -108- is damaged by hitting the shutter -41- which covers the opening -37- of the disc cartridge -26-.

On the other hand, the part of the disc cartridge -26- on which the openings -36 and 37- are formed is inserted between the magnetic head -108- and the pad -128-. By locking the loading of the disc cartridge -26- with the charging device, not shown, the pad fixing part -129- in the direction of arrow H of FIG. 12 and 24 pivoted by the force of the compression spring -133-, whereby a part of the flexible magnetic plate -21-, the opening -45- in the closure -41-, the openings -36 and 37- in the cassette shell -22- and the The opening -38- in the non-woven fabric -35- is exposed, held between the magnetic head -108- and the pad -128-.

If, in this case, the pawl -47-, which prevents erroneous erasure, the disc cartridge -26- has not been bent,. the scanner -143- of the scanning member -140- is pressed against the force of the helical compression spring -141- of the pawl -47- down, as shown in Fig. 26 dash-dotted lines. Thereby, the gap between the light-emitting and the light-receiving component of the detector -144- can be interrupted. The device -60- is thus ready to perform a recording and reproducing operation on the basis of a predetermined signal of the detector -144-. On the other hand, if the pawl -47- has been bent, the front end of the scanner -143- of the scanning part -140- can enter the recess -46- of the cassette shell -22-. By the helical compression spring -141-, therefore, the scanning part -140- remains in the upper position, so that the gap between the light-emitting and the light-receiving component of the detector -144- is not interrupted. The device -60- thus remains in a state in which on the basis of a predetermined signal of the detector -144- no sign operation is possible.

In such a loading operation of the disc cartridge -26-, the motor shaft -83b- is inserted into the center hole -24- of the center core disc -23- which fits into the drive port -28- of the lower half -22b- of the disc cartridge -26-. In this case, when the upper plate -22c- of the loaded disc cartridge -26- is warped (bent) toward the lower disc -22d, as shown in phantom in Fig. 27, the hemispherical tip -83c- contacts the motor shaft -83b - Nearly the middle of the inner surface of the upper plate -22c-. As a result, acts on the upper plate -22c- through the pins -75, 76, 77 and 78- a force in the direction of arrow 3 and K of Fig.27. When the loading of the disc cartridge -26- is over, the deformation (inward discarding) of the upper disc -22a is already corrected, and the upper disc -22a- is flat, as shown in solid lines in Fig. 27.

On the other hand, when the disc cartridge -26- is inserted, the pressure point of the pins -75, 76, 77 and 78- of the pressing portion -72- on the diagonal of the pins -63, 64, 65 and

66-, as mentioned above. The pressure points are those locations that correspond to the ribs -33 and 34- the disc cartridge -26-. Therefore, when the lower plate -22d- of the disc cartridge -26- to be inserted is deformed inwardly, ie, toward the upper disc -22c-, as shown in phantom in Fig. 27, a force acts on the lower disc -22d- in the direction of arrow L. and M over the ribs -33- of the upper half -22a and over the ribs -34- of the lower half -22b-. As a result, the deformation of the lower plate -22d- is corrected and the lower plate -22d- becomes flat, as shown in Fig.27 in solid lines.

As mentioned above, in this embodiment, this warp (deformation) can be satisfactorily corrected even if both the upper and lower plates 22c and 22d are inwardly warped (deformed). Thus, the gap in the cassette shell -22-, when it is inserted, are always kept constant, so that the risk of an obstacle to the rotation of the magnetic disk -21- is no longer given and the flexible magnetic disk -21- with a relatively small Drive torque can be set in rotation.

In the above-mentioned insertion (loading) of the disk cartridge -26-, the center core disk -23- is attracted by the magnets -104- of the yoke -90- and on the lubricating films -105

- 13 No.373422 and 106-, which are glued to the upper surfaces of the flanges -90a and 90b- of the yoke -90-. In this case, when the position of the driving and adjusting hole -25- in the center core disk -23- and the spring-biased pin -85- are shifted from each other, the pin -85- from the center core disk -23- becomes downward by the attraction force pressed between the central core disc -23- and the magnets -104- acts. As shown in Fig.20 with solid lines, the pin -85- is pressed against the spring force of the leaf spring -86- and in particular of the arm portion -85- down. In this state, when the apparatus -60- is switched to the recording or reproducing mode and the motor shaft -83b- of the motor -83- rotates, the pin -85- rotates together with the leaf spring -86- and the yoke -90 - to the center core disk -23-. At this time, the flexible magnetic plate -21- is held between the magnetic head -108- and the pad -128-, as described above, whereby a load torque is applied to the magnetic plate -21-. Therefore, even if a frictional force is applied between the lubricating sheets -105 and 106- pasted on the yoke 90 and the center core disk -23- as well as between the center core disk -23- and the pin -85-, the center core disk - 23- is not rotated and pin -85- moves relative to the stationary center core disk -23-. Then, when the driving and adjusting hole -25- is reached in the center core disk -23-, as shown in phantom in Fig. 28, the cylindrical part -101- of the pin -85- penetrates by the spring force of the leaf spring -86- the opening -25-. As the motor shaft -83h- rotates in the direction of the arrow N, the pin -85- is moved further and the cylindrical portion -101- of the pin -85- first locks into a setting edge -25a-, that of the motor shaft -83b- on outside of two longer edges of the opening -25-. Then the pin -85- is moved on and engages in a drive edge -25b- the opening -25-, while the cylindrical portion -101- of the pin -85- with the ball bearing -100- is rotated, since a holding force, induced by the magnetic head -108 and the pad -128- and an inertial force caused by the rotational speed difference between the yoke 90 and the center core disk -23-, act as load moment on the magnetic disk -21- and the central core disk -23-. In this case, the pin -85- is tilted by a torsional deformation of the arm portion -95- of the leaf spring -86-, as shown in Fig. 21, since, as already mentioned above, the distance -Sl- of Fig. 19 made slightly longer is as the distance -S2- of Fig.28. The axis of the pin -85- is thus slightly inclined with respect to the vertical of Fig.21, so that normally on the central core disk -23- a pressing force in the direction of arrow P of Fig.21 and 28 over the cylindrical portion -101- of the pin Is exerted by the restoring force of the arm part of the leaf spring -86-.

Although the load moment exerted by the magnetic head -108 and the pad -128- on the flexible magnetic plate -21- is small, the pin -85-, since in this embodiment the ball bearing -100- between the shaft portion -98- and the cylindrical Part -101- is provided, even then safely move to the predetermined position, which is shown in FIG. 28 with solid lines is when the insertion openings -24 and 25- were made in the central core disk -23- with no great dimensional accuracy.

Since the center core disk -23- is moved in the direction of arrow P, the two sides -24a and 24b- of a V-shaped corner, which is farther outward from the drive and adjustment hole -25- of the four sides of the Motorwelleneinsetzöffnung -24- on two places are pressed to the motor shaft -83b- and the center core pulley -23- is adjusted. Thus, the center of the flexible magnetic plate -21- adhered to the center core disk -23- is located almost on the axis of the motor shaft -83b-. In this state, when the motor shaft -83b- rotates and the pin -85- is moved in the direction of the arrow N of Fig. 28, the cylindrical portion -101- of the pin -85- abuts the driving edge -85b- of the opening -25 -, so that the central core disk -23- and thus the magnetic disk -21- in the direction of arrow N is rotated. In this case, since the flexible magnetic plate -21- is arranged concentrically with the motor shaft -83b-, as mentioned above, it is rotated in a substantially centered state.

The operation of the head moving device will now be described. If first that

- 14 Nr.373422

For example, if the apparatus -60- is switched to the reproducing operation and the disc cartridge -26- is loaded in the above-mentioned manner, the flexible magnetic disc -21- rotates in the aforementioned manner. Along with this rotation, recorded information is read out from the magnetic head -108- which slidably contacts the recording surface of the flexible magnetic disk -21-, and a synchronizing signal included in the read-out information is sent to a drive stage of the stepping motor (not shown). placed. Each time such a synchronizing signal is provided, the above-mentioned driving stage supplies a predetermined driving current to the stepping motor -111-, whereby the motor shaft -lila- is stepped in the arrow direction Q of Figs. 12 and 24 by a predetermined rotation angle (eg 15 °) Rotation is offset. Together with the rotation of the motor shaft -lila- the needle-shaped part -124-, which lies without play between adjacent threads of the feed spindle -112-, of the feed spindle -112- in the direction of arrow S is moved. Thus, the head holder -110- is guided along with the needle-shaped portion -124- of the guide axis -116- and moves stepwise to the next circular recording track in the direction of arrow S, that is, in each revolution of the flexible magnetic disk -21-. Both the magnetic head -108- and the pad-fixing part -129-, both of which are mounted on the head holder -110-, slide together with the flexible magnetic plate -21- held therebetween. They progressively move longitudinally within the head and cushion insertion holes -36 and 37- in the disk cartridge, ie, in the radial direction of the flexible magnetic disk -21-.

In this embodiment, since the pitch of the feed spindle -112- is relatively small, and the stepping motor -111- has a relatively large rotation angle (eg, about 15 °) in one step, it is possible to adjust the head -108-in In view of the reproduced recording track when the recording track pitch on the flexible magnetic disk -21- is small. This is because the ratio of the mechanical accuracy to the rotation angle of a step is smaller in a stepping motor having a larger rotation angle, even if the stepping motor has the same mechanical accuracy with one turn rotation. The magnetic head -108- can thus be moved with great accuracy.

During the movement described above, a downward force is exerted on the feed spindle -112- in Figs. 24 and 25 via the needle-shaped part -124-. However, since a pressure force is always exerted on the feed spindle -112- from the leaf spring -127- to the needle-shaped part -124-, the threads of the feed spindle -112- and the needle-shaped part -124- never snap apart.

In this way, the magnetic head -108-, which is in sliding contact with the flexible magnetic plate -21-, moves stepwise and radially from the outer edge to the center of the magnetic disk -21- every revolution of the motor shaft -83b-, ie, always, when a synchronizing signal is applied, which is recorded on each circular recording track. When the head holder -110- has been moved to a predetermined position and the magnetic head -108- has almost reached the inner peripheral portion of the magnetic surface of the flexible magnetic disk -21-, this position of the head holder -110- is scanned by a scanner -137a. Then, when the detector -137- and the reflector -136- come to face each other in the rotation of the motor shaft -lila- of the stepping motor -111-, the rotation of the motor shaft -lila- in the direction of the arrow N due to the scanning signal of the above Scanning device -137a- and the reflector -137- stopped. On the other hand, when the feed spindle -112- has been rotated in the direction of arrow R of Figs. 12 and 24 by the stepper motor -111-, the magnetic head -108- is moved from the radial center side of the flexible magnetic plate -21- to the outer edge (in the direction of arrow I of Figs Figs. 12 and 24). When it has reached the outer peripheral portion of the magnetic surface, the rotation of the motor shaft -lila- is stopped, which is opposite to the above-mentioned arrow direction N.

Along with the above-described operation, the information recorded on the recording surface of the flexible magnetic disk -21- is reproduced. Further, in the recording operation, the same operation as described above is performed.

According to the flexible magnetic disk cartridge -26- having the above-described structure, the center core disk -23- is formed into a pan shape and the center cavity -23a

No.373422 of the central core disk -23- and the projection -30- of the upper half -22a are kept fitting to each other, so that even when the flexible magnetic disk -21- is moved to the lower half -22b- due to its own weight, when the disk cartridge -26- is not used, the movement of the center core disk -23- and thus the magnetic disk -21- in its planar direction is surely restricted within a predetermined range, that the central core disk -23- and the projection -30- engage each other. Thus, the danger can be eliminated that the edge portion of the flexible magnetic plate -21- comes into contact with the ribs -33 and 34- and is thereby damaged. Especially in a flat disk cartridge, it is preferable that the moving range in the vertical direction of the center core disk is made as large as possible in consideration of dimensional variations of various components. By making the center core plate -23- of this embodiment cup-shaped, it becomes possible in this connection to make the range of movement larger than that of the plate-shaped center core plate -6-, as shown in FIG.

Even if, as mentioned above, the upper plate -22c and the lower plate -22d- of the cassette shell -22- are deformed away from each other due to a low mechanical strength of the cassette shell -22-, the range of movement of the center core plate -23- can be assured be restricted. Since the center core disk -23- is constructed of a thin plate, it is possible to lower its weight as compared with a conventional disk-shaped center core disk, whereby a small low-torque motor can be used as the drive source for the magnetic disk -21-.

Further, in assembling the flexible magnetic disk -21- and the center core disk -23-, the kovexe portion -23b- serves the center core disk -23- as a guide, whereby the magnetic disk -21- can be fixed with high accuracy with respect to the center core disk -23- , As a result, vibrations which act on the flexible magnetic plate -21 during the rotation from outside can be kept to a minimum.

Further, the distance from the yoke -90- to the inner surface of the upper plate -22c- of the upper half -22d-home insertion of the disk cartridge -26- can be made relatively large, whereby the tip -83c- of the motor shaft -83b- can be formed hemispherical , Even if no opening is formed in the upper plate -22c, which is aligned with the motor shaft -83b-, the center core plate -23- can be fully guided by the tapered part.

In the above description, an embodiment of the invention has been explained, but the invention is not limited thereto, so various modifications can be made on the basis of the technical idea of ​​this invention.

For example, the material of the center core disk -23- is not limited to iron, but other magnetic materials may be used. Further, the center core disk -23- can be made of a hard material containing a magnetic powder.

In view of the aspect ratio between the upper and lower halves -22a and 22h- of the cassette shell -22- and the center core disk -23-, the values ​​of LI to L12 given above are by way of example only and may be changed if only the overlap exists between the projection -30- of the upper half -22a and the lower half -22b-. Further, it is possible to form the protrusion -30- on the lower half -22b- so as to protrude to the upper half -22a and insert into the central cavity -23a of the center core disk -23-.