Disk cartridge with finger-like holding members and three-part supporting feature

A disk cartridge of the present invention comprises a case body (101) having a disk-storage portion and an opening/closing cover (201) having a pair of disk holding members (202) that hold a disk (10) in its inplane direction. The accommodated disk (10) is loaded together with the opening/closing cover (201) into an adapter having compatibility with a large disk cartridge. Thus, information can be, for example, reproduced from the disk (10) in a drive unit designed for a large disk cartridge via the adapter. Moreover, a series of operations can be conducted without touching the disk directly.

FIELD OF THE INVENTION
 First Invention
 The present first invention relates to a disk cartridge accommodating a
 disc-shaped recording medium and to a cartridge adapter capable of
 recording information on and reproducing information from the disc-shaped
 recording medium accommodated in the disk cartridge using a drive unit
 designed for a larger disk cartridge than the disk cartridge.
 Second Invention
 The present second invention relates to a disk cartridge for double-sided
 recording that accommodates a disk as a disc-like recording and
 reproducing medium such as an optical disk. Particularly, the present
 second invention is suitable for providing a smaller and thinner disk
 cartridge.
 Third Invention
 The present third invention relates to a disk cartridge accommodating a
 disk for recording and reproducing information. Particularly, the present
 third invention relates to a disk cartridge comprising a shutter for
 exposing a disk surface in order to drive a disk for recording,
 reproduction and the like.
 BACKGROUND OF THE INVENTION
 First Invention
 With the rapid progress of computer techniques, disc-shaped recording media
 have been used widely as means for recording, reproducing, and erasing
 various information. With respect to disc-shaped recording media, there
 are a plurality of standards that differ in recording density, size,
 recording and reproducing system, and the like respectively. Corresponding
 to the respective disc-shaped recording media according to the plurality
 of standards, there are also a plurality of drive units for recording
 information on and reproducing and erasing information from the respective
 disc-shaped recording media.
 Under such circumstances, it is convenient for users when disc-shaped
 recording media according to a plurality of standards can be driven for
 recording, reproducing, and erasing information with one drive unit.
 Therefore, various systems have been proposed.
 As a method for driving a plurality of disc-shaped recording media having
 different sizes for recording, reproducing, and erasing information with
 one drive unit, for example, a method in which a user inserts a bare
 disc-shaped recording medium into an adapter and then sets it into a drive
 unit has been proposed. Partially, this method has come into practical use
 for driving both a compact disc (CD) with a diameter of 12 cm and a single
 compact disc with a diameter of 8 cm.
 As a method of recording information on and reproducing and erasing
 information from disc-shaped recording media with various sizes
 accommodated in cartridges with one drive unit, for example, as shown in
 FIG. 51, a method of recording, reproducing, and erasing information in a
 drive unit 1921 designed for a large disk cartridge by inserting a
 small-size disk cartridge 1901 into a cartridge adapter 1911 having the
 same size and the same external shape as those of the large disk cartridge
 has been studied (for instance, Publication of Japanese Unexamined Patent
 Application Hei 2-121174). In FIG. 51, numerals 1912 and 1913 indicate a
 head access opening and a shutter of the cartridge adapter 1911,
 respectively. The head access opening 1912 and the shutter 1913 are formed
 so as to have the same shapes and sizes as those of the cartridge for a
 large disc. Numerals 1902 and 1903 indicate a head access opening and a
 shutter of the small disk cartridge 1901, respectively. A numeral 1914
 indicates an insertion portion into which the small disk cartridge 1901 is
 inserted, and a numeral 1924 indicates an insertion portion into which the
 large disk cartridge is inserted.
 However, the method in which a user inserts a bare disc-shaped recording
 medium into an adapter and sets it into a drive unit is not suitable for
 the use that requires high reliability and high durability, since the user
 can put dirt and scratches on the disc-shaped recording medium easily.
 Further, in the method of recording, reproducing, and erasing information
 in a drive unit designed for a large disk cartridge by inserting a small
 disk cartridge into a cartridge adapter having the same size and the same
 external shape as those of the large disk cartridge as shown in FIG. 51,
 for example, the following problems occur. The small disk cartridge is
 different from the large cartridge in shapes and sizes of the head access
 opening and the shutter that are provided in a disk cartridge, and in the
 opening/closing mechanisms of the shutter. Therefore, some problems occur,
 for example, a head of the drive unit comes into contact with the shutter
 1903 and the exterior members around the head access opening 1902 of the
 small disk cartridge 1901 accommodated in the cartridge adapter 1911, and
 the mechanism for opening and closing the shutter is complicated. As a
 result, in disk cartridges with different sizes, it is difficult to
 record, reproduce, and erase information without any problems using such
 an adapter. Considering such use, it has been necessary to review the
 design of the drive unit itself in some cases.
 Second Invention
 Recently, disk drive units for optical disks or the like used as recording
 units of computers have been required to be smaller and thinner, as
 portable computers have become widespread. At the same time, disks for
 recording and reproduction have become smaller, and therefore the disks
 with high recording-density have been required. Such a disk is
 accommodated in a cartridge case so that fingerprints and dust, which are
 obstacles for recording and reproducing information at a high density, do
 not adhere to the disk.
 An example of a conventional double-sided disk cartridge and a mechanism of
 opening and closing its shutter will be explained with reference to the
 drawings as follows.
 FIG. 61 is a perspective structural view of a disk cartridge in conformity
 with the International Standard for a 130-mm optical disk. FIG. 62 is a
 perspective view showing a state in which a shutter of the disk cartridge
 shown in FIG. 61 is opened. FIG. 63 is a partially enlarged perspective
 view showing a configuration around the shutter of the disk cartridge
 shown in FIG. 61. In this conventional disk cartridge, an optical disk
 2104 is accommodated in a case body 2103 having a substantially
 rectangular shape formed of an upper half 2101 and a lower half 2102. An
 opening 2105 into which a disk motor and an optical pickup can be inserted
 is provided in the upper and lower surfaces of the case body 2103. A
 U-shaped shutter 2106 for covering and uncovering the opening 2105 is
 slidably provided on the case body 2103. The shutter 2106 is formed in a
 manner such that a metal plate is folded in two. The shutter 2106
 comprises two opposed shielding plates 2107 and a connecting plate 2108
 interconnecting the two opposed shielding plates. The connecting plate
 2108 fixes and holds a thin and long slider 2109 so as to cover the slider
 2109. A receiving hole 2110 into which a shutter opener P1 is inserted is
 provided to a tail portion of the connecting plate 2108. The shutter
 opener P1 is provided in a loading mechanism of a recording and
 reproducing unit. Corresponding to the receiving hole 2110, a receiving
 hole 2111 is provided in the slider 2109. A roller R1 of the shutter
 opener P1 shown in FIG. 63 is engaged with the receiving hole 2111.
 Atorsion coil spring 2114 is housed in the left side of the leading end of
 the case body 2103. This torsion coil spring 2114 urges the shutter 2106
 in the direction in which the shutter 2106 covers the opening 2105.
 At an end of the slider 2109, a slope 2115 is provided so that a roller R2
 of a shutter opener P2 provided in the loading mechanism of the recording
 and reproducing unit as shown in FIG. 63 can pass over the slope 2115
 smoothly.
 When this conventional disk cartridge is inserted into the recording and
 reproducing unit, one shutter opener P1 is inserted into the receiving
 hole 2110 of the shutter 2106 and the receiving hole 2111 of the slider
 2109. When the shutter opener P1 moves the shutter 2106 to the left to
 uncover the opening 2105 as shown in FIG. 62, the other shutter opener P2
 crosses over and along the slope 2115 of the slider 2109. As a result, the
 shutter openers P1 and P2 cross each other.
 Guide grooves 2116 for preventing erroneous insertion of a cartridge are
 formed at the leading ends of both side faces of the case body 2103. When
 the disk cartridge is inserted into a unit normally, auto-loading hooks
 (not shown in the figures) that are a loading means of the recording and
 reproducing unit are inserted into the guide grooves 2116, thus pulling
 the disk cartridge into the unit. On the other hand, when the disk
 cartridge is inserted into the recording and reproducing unit from its
 back, the auto-loading hooks come into contact with the back corners of
 the case body 2103. Therefore, the disk cartridge cannot be inserted any
 further, thus preventing the erroneous insertion. Consequently, damage to
 an optical head that is an information writing and reading means of the
 recording and reproducing unit and other mechanisms can be avoided.
 At the rear of the both side faces of the case body 2103, grooves 2117 for
 engaging with a chucking (cramping) mechanism (not show in the figures) of
 a changer unit are formed. As widely known, one of a plurality of disk
 cartridges accommodated in a changer unit is selected and the chucking
 mechanism engages with grooves 2117 of the selected disk cartridge to hold
 and load it, thus enabling automatic selection and automatic
 recording/reproduction.
 However, there have been the following problems in the double-sided disk
 cartridge having the above-mentioned conventional structure.
 During the operation of opening and closing a shutter, the rollers at the
 ends of two shutter openers cross each other on the connecting plate 2108.
 Therefore, when a space is provided in order to avoid the contact between
 the two rollers, it is necessary to increase the thickness of the
 cartridge, which, as a result, goes against the trend to a thinner unit.
 Further, in order to obtain a thin unit, there is a cartridge in which the
 front-end center of the case body 2103 is formed of a bridge portion that
 is recessed from the two case faces so as to allow an optical head (not
 shown in the figure) of the unit and a cramp mechanism (not shown in the
 figure) for the disk to pass through. However, since such a bridge portion
 is further thinner than the cartridge, the rollers of the shutter openers
 cannot come into contact with the thinner bridge portion. Even if the
 rollers can come into contact with the bridge portion, the rollers are in
 contact with the bridge portion merely slightly. Consequently, in view of
 reliability, it has been difficult to apply such a cartridge to the
 double-sided disk cartridge.
 Next, a conventional disk cartridge has a configuration in which one of the
 shutter openers (the shutter opener P2 in FIG. 63) shifts from the front
 end of the case body 2103 to the connecting plate 2108 of the shutter
 2106. In the conventional disk cartridge, consideration is given to a
 smooth shift by providing the slope 2115 to the slider 2109. However,
 there has been a problem in that design errors and the like cause
 difference in level and therefore shift load resistance increases during
 the shift, resulting in bad operational feeling.
 Since guide grooves 2116 for preventing erroneous insertion are provided at
 the leading ends of the both side faces of the case body, the space inside
 the case body becomes smaller. Therefore, the space in which the torsion
 coil spring 2114 that provides force to the shutter 2106 is moved and the
 moving distance of the slider 2109 are smaller and shorter than those in
 the case where no guide groove 2116 is provided. On the other hand, when
 the space required for the movement of the torsion coil spring 2114 is
 provided, the disk cartridge becomes bigger. Thus, it is not suitable for
 obtaining a smaller disk cartridge.
 Further, since grooves 2117 for a changer unit are provided at the rear of
 the both side faces of the case body 2103, there is a possibility of
 damaging the peripheral surface of the disk 2104 through the contact with
 edges of the grooves 2117 during ejection of the disk 2104, when the disk
 2104 is applied to a cartridge in which the disk 2104 is ejected from the
 back of the case body 2103. In order to avoid this, it is necessary to
 make the disk cartridge bigger so as to have an extra space at least for
 the grooves 2117, resulting in a bigger disk cartridge.
 Thus, the configuration of the conventional double-sided disk cartridge
 does not enable the disk cartridge to be smaller and thinner. Therefore,
 there has been a problem in that it is difficult to obtain a smaller drive
 unit.
 Third Invention
 Recently, in view of large recording capacity, excellence in information
 search, easy handling, and the like, disks of disc-shaped recording media
 and disk recording and reproducing units that drive the disks have
 received much attention.
 Such a disk is accommodated in a cartridge with a shutter so that the
 cartridge prevents a recording surface of the disk from being damaged or
 from being touched easily and keeps the recording surface away from dirt.
 A configuration of a conventional disk cartridge will be explained with
 reference to the drawing as follows.
 FIG. 68 shows plan views showing a structure of a conventional disk
 cartridge. FIG. 68(A) and (B) show the conventional disk cartridge with
 its shutter being closed and being opened, respectively.
 In FIG. 68, a numeral 3101 indicates a cartridge body, which is made of
 synthetic resin. The cartridge body 3101 accommodates a disk 3103 of a
 recording medium rotatably. A numeral 3101a indicates an opening provided
 on both sides of the cartridge body 3101. The openings 3101a are used for
 exposing surfaces of the disk 3103 so that light can be irradiated onto
 the disk 3103 across its inner and outer peripheries for recording and
 reproduction. The cartridge body 3101 shown in FIG. 68 is provided so that
 a center hole is completely exposed through the openings 3101a, since it
 is necessary that a disk recording and reproducing unit holds the center
 hole to rotate the disk 3103. A numeral 3102 indicates a shutter that is
 formed of a thin plate made of metal such as aluminum, or a synthetic
 resin plate. The shutter 3102 is maintained by the cartridge body 3101
 slidably so as to cover the openings 3101a completely to shield the disk
 3103 or so as to uncover the openings 3101a to expose the disk 3103.
 The operation of such a conventional disk cartridge will be explained.
 When the cartridge body 3101 having the shutter 3102 is loaded in a disk
 recording and reproducing unit, a concave part 3102a provided in the
 shutter 3102 engages with an opener lever OL of the disk recording and
 reproducing unit as shown in FIG. 68(A) and the shutter 3102 slides to the
 right (in the direction indicated with an arrow O in FIG. 68). Thus, the
 openings 3101a are uncovered. On the other hand, when the cartridge body
 3101 is drawn out from the recording and reproducing unit, the shutter
 3102 slides to the left (in the direction indicated with an arrow S in
 FIG. 68) by a shutter return spring 3104 inside the cartridge as shown in
 FIG. 68(B) to return to the initial position. Thus, the shutter covers the
 openings 3101a and thus the disk surfaces are not exposed. The cartridge
 body 3101 has the above-mentioned configuration.
 As shown in FIG. 68(B), the conventional disk cartridge had a configuration
 in which the shutter 3102 that has been moved to the side is not
 positioned outside the cartridge body 3101 beyond its peripheral end when
 the shutter 3102 is opened to expose the openings 3101a completely.
 That is to say, as shown in FIG. 70, the conventional disk cartridge had a
 configuration in which L3=L2&gt;L1.gtoreq.L0 is satisfied, wherein with a
 closed shutter, L represents the width of the disk cartridge (cartridge
 body) in the sliding direction of the shutter, L0 represents the width of
 the opening, L1 is the width of the shutter, L2 is the distance between
 the leading end of the shutter in its sliding direction and the peripheral
 end of the cartridge body that is nearer to the above-mentioned leading
 end (the width of a region where the shutter is positioned when being
 moved to the side), and L3 represents the distance between the rear end of
 the shutter in its sliding direction and the peripheral end of the
 cartridge body that is nearer to the above-mentioned rear end (generally
 L3=L2). In this case, the width L of the whole cartridge had to be set to
 satisfy L3+L1+L2&gt;3.times.L1 inevitably.
 However, in the above-mentioned conventional disk cartridge, when the
 openings 3101a become larger, the shutter 3102 covering the openings 3101a
 also becomes larger. At the same time, the required space for positioning
 the shutter when the shutter is moved to the side becomes larger.
 Consequently, there has been a problem in that the cartridge itself comes
 to have a large size.
 Especially, as shown in FIG. 69, in a disk cartridge for a small-diameter
 disk 3003 in which only its capacity is reduced by decreasing the disk
 diameter without changing its recording and reproducing system and drive
 system and in which its small size, light weight, and portability are
 considered as important, the size of an opening 3111a, especially its
 width in the sliding direction is fixed. Therefore, the width of a shutter
 3112 and the width of the region where the shutter 3112 is positioned when
 being moved to the side are increased. As a result, only the cartridge
 size is larger than needed for the small-diameter disk 3003, which has
 been a disadvantage.
 SUMMARY OF THE INVENTION
 First Invention
 The present first invention aims to solve the above-mentioned conventional
 problems. It is an object of the present first invention to provide a disk
 cartridge and an adapter. The disk cartridge and the adapter can secure
 reliability of information and durability of a disk by enabling that
 information is recorded on and reproduced and erased from a disc-shaped
 recording medium accommodated in a disk cartridge in a drive unit designed
 for a disk cartridge having a larger size than that of the disk cartridge
 via an adapter. At the same time great modification in a drive unit design
 is not required, and the disc-shaped recording medium is loaded to the
 adapter without being touched directly.
 The present first invention employs the following configuration in order to
 attain the above-mentioned object.
 A disk cartridge of the first present invention comprises a case body
 having an opening for ejecting a disk and a disk-storage portion provided
 continuously to the opening, and an opening/closing cover having a pair of
 disk holding members that hold the disk. The opening/closing cover is
 accommodated in the disk-storage portion in a withdrawal condition. When
 the opening/closing cover is withdrawn from the disk-storage portion, the
 pair of the disk holding members maintain the disk in its inplane
 direction.
 According to the disk cartridge with the above-mentioned configuration,
 information can be recorded, reproduced, and erased by loading the disk
 cartridge to a drive unit designed for a disk cartridge having
 compatibility with the disk cartridge without any modification. At the
 same time, by providing a predetermined adapter as an intermediate,
 information can be recorded, reproduced, and erased even in a drive unit
 designed for a larger disk cartridge than the disk cartridge with the
 above-mentioned configuration. Furthermore, great design modification in
 the drive unit designed for a larger disk cartridge is not required, and
 the reliability of the information and the durability of the disk can be
 secured, since a user does not touch the disc-shaped recording medium
 directly.
 The adapter of the present first invention comprises: an insertion portion
 into or from which a disk cartridge can be loaded or ejected; a first
 unlocking means that unlocks a first locking means that fixes and holds
 the opening/closing cover of the disk cartridge to the case body when the
 disk cartridge is inserted to a predetermined position in the insertion
 portion; an opening/closing-cover holding means that retains the
 opening/closing cover in a state in which the first locking means has been
 unlocked and holds the opening/closing cover at the predetermined position
 in the insertion portion after the case body is drawn out from the
 insertion portion; and a means for releasing the opening/closing-cover
 holding means that allows the opening/closing cover to be withdrawn from
 the insertion portion by releasing the opening/closing-cover holding
 means.
 According to the adapter having the above-mentioned configuration,
 information can be recorded on and reproduced and erased from a smaller
 size disk in a drive unit designed for a larger disk cartridge having
 compatibility with the adapter described above. Moreover, great design
 modification in the drive unit designed for a larger disk cartridge is not
 required, and a user does not touch the disc-shaped recording medium
 directly, thus securing the reliability of information and the durability
 of the disk.
 Second Invention
 It is an object of the present second invention to provide a disk cartridge
 for double-sided recording and reproduction with a smaller and thinner
 size so as to obtain a small and thin drive unit.
 In order to attain the above-mentioned object, the disk cartridge of the
 present second invention has the following configuration.
 A disk cartridge according to a first configuration of the present second
 invention is a double-sided disk cartridge that can be used reversibly.
 The disk cartridge comprises a case body and a U-shaped shutter. The case
 body comprises a disk-storage portion for accommodating a disk inside the
 disk cartridge and openings formed on two case faces opposing the disk.
 The U-shaped shutter comprises two shielding plates that cover and uncover
 the two openings and a connecting portion. The connecting portion
 interconnects the two shielding plates and is positioned so as to face the
 front end of the case body. The U-shaped shutter is guided movably along
 the front end of the case body. The shutter has an engagement portion
 formed continuously to the two shielding plates so as to cross the
 connecting portion. The engagement portion is capable of engaging with one
 of two shutter openers provided in a unit when the disk cartridge is
 loaded into the unit. A guide portion is provided at the front end of the
 case body and guides the shutter by coming into contact with the other
 shutter opener when the one shutter opener engages with the engagement
 portion to open and close the shutter. The engagement portion and the
 guide portion are arranged so that a region where the engagement portion
 is moved and the guide portion do not overlap each other. According to the
 first configuration, the disk cartridge can be formed so that rollers of
 the two shutter openers do not cross each other during the opening/closing
 operation of the shutter. Therefore, while the disk cartridge enables a
 smooth opening/closing operation, at the same time the cartridge can be
 made thin without decreasing the size of the disk-storage portion in which
 the disk is stored. This also enables the size and thickness of a drive
 unit to be decreased.
 In the first configuration, it is preferable that the disk cartridge has a
 bridge portion that is recessed from the two case faces at the front-end
 side of the openings of the case body and the engagement portion is
 positioned movably along the front end of the case body including the
 bridge portion. According to such a preferable configuration, the
 thickness of a recording and reproducing unit can be decreased by forming
 the unit so that an optical head of the unit and a cramp mechanism of a
 disk pass over the bridge portion region that is recessed from the case
 faces.
 In the first configuration, it is preferable that a notch is provided to
 the connecting portion, an engagement portion capable of engaging with the
 notch is formed in the guide portion, and the guide portion is at
 substantially the same level as that of the surface of the connecting
 portion or projects from the surface. According to such a preferable
 configuration, the shutter openers are guided only on the guide portion
 including the engagement portion, and therefore the difference in level in
 the region where the shutter openers are guided is avoided. Consequently,
 the shutter openers can be moved smoothly and moving load resistance does
 not increase, thus obtaining excellent operational feeling.
 A disk cartridge according to a second configuration of the present second
 invention is a double-sided disk cartridge that can be used reversibly.
 The disk cartridge comprises a case body and a U-shaped shutter. The case
 body comprises a disk-storage portion for accommodating a disk inside the
 disk cartridge and openings formed in two case faces opposing the disk.
 The U-shaped shutter comprises two shielding plates that cover and uncover
 the two openings, and a connecting portion. The connecting portion
 interconnects the two shielding plates and is positioned so as to face the
 front end of the case body. The U-shaped shutter is guided movably along
 the front end of the case body. The shutter has an engagement portion
 formed continuously to the two shielding plates so as to cross the
 connecting portion. The engagement portion is capable of engaging with one
 of two shutter openers provided in a unit when the disk cartridge is
 loaded into the unit. The disk cartridge has a second guide portion
 capable of coming into contact with the shutter openers that is provided
 at the rear end side of the case body and a retaining portion that is
 formed continuously to the second guide portion and that retains the
 shutter openers. The second guide portion and the retaining portion are
 provided within the moving range of the shutter opener. According to such
 a second configuration, in the case of erroneous insertion of the disk
 cartridge into a drive unit, the shutter openers come into contact with
 and are guided by the second guide portion to be retained by the retaining
 portion, thus regulating the insertion of the cartridge. Therefore, guide
 grooves for preventing erroneous insertion that are formed at the ends of
 both sides of a conventional case body can be omitted. Thus, the space
 where a torsion coil spring providing force to the shutter moves and the
 moving distance of a slider can be increased compared to those in the case
 where the guide grooves are provided. As a result, a smaller cartridge can
 be obtained.
 In the second configuration, it is preferable that a pair of retaining
 portions are arranged symmetrically with respect to the center line of the
 case body. According to such a preferable configuration, erroneous
 insertion can be regulated by the shutter openers regardless of the side
 of the disk cartridge, and the bias of the load that is applied to only
 one of the two shutter openers at the time of the regulation can be
 avoided.
 In the second configuration, it is preferable that the retaining portion
 has a hook-shaped part formed in a hook shape when it is seen from the
 case face side. According to such a preferable configuration, the
 hook-shaped part can engage with a chucking mechanism of a changer unit.
 Consequently, conventional grooves at the rear of the both sides of the
 case body can be omitted. As a result, a smaller disk cartridge can be
 obtained. Further, when such a disk cartridge is applied to a cartridge in
 which a disk is ejected from the back face of the case body, the damage to
 the disk caused by the contact of the peripheral side surface of the disk
 with edges of the grooves when the disk is ejected is avoided.
 In addition, in the first and second configurations, it is preferable to
 form an opening/closing cover for ejecting a disk at the rear end of the
 case body. According to such a configuration, a disk can be ejected.
 Third Invention
 The present third invention aims to solve the above-mentioned problems. It
 is an object of the present third invention to provide disk cartridges
 having respective sizes conforming to disks having large and small
 diameters.
 In order to attain the above-mentioned object, the disk cartridge of the
 present third invention is formed without increasing the width of a region
 where a shutter is positioned after being moved to the side, thus
 preventing the cartridge size from being increased.
 The disk cartridge of the present third invention comprises a disk, a
 substantially rectangular cartridge body and a shutter. The disk is a
 disc-shaped recording medium. The cartridge body accommodates the disk
 rotatably and has an opening for exposing the disk. The shutter is
 slidably held along one side of the cartridge body and covers at least the
 opening completely. The opening is formed so as to be positioned
 substantially perpendicular toward one side of the periphery of the
 cartridge body from substantially the center of the disk with a
 predetermined width. In the disk cartridge of the present third invention,
 L0.gtoreq.L2 is satisfied, wherein L0 indicates the width of the opening
 in a sliding direction of the shutter and L2 indicates the distance
 between the leading end of the shutter in its sliding direction and the
 peripheral end of the cartridge body that is nearer to the above-mentioned
 leading end when the shutter is closed. According to such a configuration,
 the width of the region where the shutter is positioned when being moved
 to the side is designed so as to be the same as or narrower than the width
 L0 of the opening. Therefore, when the disk cartridge accommodates a
 small-diameter disk, a small disk cartridge corresponding to the disk size
 can be obtained.
 In the above-mentioned configuration, it is preferable that the disk
 cartridge accommodates a disk having the same recording and reproducing
 system as that of and a different outer diameter from that of a disk of a
 disc-shaped recording medium that is rotatably accommodated in an
 arbitrary disk having an opening for exposing the disk accommodated
 therein, and the disk cartridge has substantially the same opening width
 as that of the arbitrary disk cartridge. According to such a preferable
 configuration, a small disk cartridge corresponding to the size of an
 accommodated disk can be obtained while having a required opening size.
 In the above-mentioned configuration, the cartridge can be designed so that
 at least a part of the shutter is positioned outside the cartridge body
 beyond its peripheral end when the shutter slides and the opening is
 completely uncovered. According to such a configuration, since the
 cartridge can have a size corresponding to the size of the accommodated
 disk regardless of the opening width, a disk cartridge having a small size
 in its width direction can be provided.
 Furthermore, in the above-mentioned configuration, the shutter can be
 formed of shutter members divided into at least two parts substantially
 perpendicularly to the sliding direction. The shutter members divided into
 at least two parts can be formed so that each part slides in the same
 direction and is positioned one upon another, thus exposing the opening.
 Further, the shutter can be formed of a first shutter member and a second
 shutter member that are formed by dividing the shutter into two parts
 substantially perpendicularly to its sliding direction. The first shutter
 member and the second shutter member also can be formed so as to slide in
 the different direction from each other. According to these
 configurations, not only the disk can be accommodated without increasing
 the size of the cartridge body in its width direction, but also the
 shutter is not positioned outside the cartridge beyond its peripheral end
 even when the opening is in an uncovered state where the shutter is
 opened.

BEST EMBODIMENTS FOR ENABLING THE INVENTION
 First Invention
 A disk cartridge and an adapter of the present first invention will be
 explained with reference to the drawings as follows.
 First Embodiment
 FIG. 1 is a schematic perspective view showing the appearance of an example
 of a disk cartridge according to a first embodiment of the present
 invention. FIG. 2 is an exploded perspective view showing schematic shapes
 of the main components of the disk cartridge shown in FIG. 1. FIG. 3 is a
 schematic plan view showing the disk cartridge shown in FIG. 1 during the
 assembly or when an opening/closing cover is withdrawn.
 As shown in FIGS. 1-3, a disk cartridge 100 according to the first
 embodiment of the present invention comprises a case body 101 and an
 opening/closing cover 201 that is accommodated in the case body 101 in a
 withdrawable state.
 The case body 101 is provided with an opening 102 into or from which a
 disc-shaped recording medium (hereafter also referred to simply as a
 "disk") 10 is inserted or ejected and a disk-storage portion 103 forming a
 space where the disk 10 is accommodated. The disk-storage portion 103 is
 provided adjoining the opening 102.
 The opening/closing cover 201 has a pair of disk holding members 202 that
 adjust the position of the disk 10 in its inplane direction and maintain
 the disk 10. The disk holding members 202 have shapes in which portions
 202a corresponding to the vicinity of the maximum width (diameter)
 portions of the disk 10 are curved outwards and their ends are curved
 inwards respectively as shown in FIG. 3. On the other hand, inner walls
 104, opposed in a disk-diameter direction of a disk-storage portion 103 of
 the case body 101, are formed so that a space between the inner walls 104
 is slightly widened in a back portion and a space between them in the
 vicinity of the opening 102 is narrowed as shown in FIG. 3. Therefore, as
 shown in FIG. 1, in the case of trying to withdraw the opening/closing
 cover 201 when the opening/closing cover 201 covers the opening 102 of the
 case body 101 completely, the portions 202a that are curved outwards in
 the disk holding members 202 of the opening/closing cover 201 come into
 contact with the inner walls 104 of the disk-storage portion 103 of the
 case body 101. Then, the portions 202a are elastically deformed so as to
 move toward each other, i.e. so as to hold the disk 10 in its inplane
 direction. Consequently, the ends of the disk holding members 202 hold the
 accommodated disk 10 without fail. Thus, the disk 10 can be ejected
 together with the opening/closing cover 201 in the state shown in FIG. 3.
 The case body 101 has a head access opening 180 so that a head for
 recording information on the disk 10 or reproducing or erasing information
 recorded on the disk 10 can scan a disk surface. Further, the case body
 101 comprises a shutter 181 for covering the head access opening 180 and
 an elastic spring 182 for maintaining the state in which the shutter 181
 is closed when the disk cartridge is not loaded in a drive unit. In
 addition, the case body 101 has a belt opener 183 that is operated
 together with the shutter 181, and an opener hook 184 that is provided at
 an end of the belt opener 183 and that is held by the drive unit when the
 drive unit opens and closes the shutter 181. Moreover, the case body 101
 has a positioning hole 185 for positioning the disk cartridge when the
 disk cartridge is loaded in the drive unit.
 The external shape and size of the disk cartridge 100 including the case
 body 101, the head access opening 180, the shutter 181, and the like are
 designed so as to secure the perfect compatibility with a disk cartridge
 standardized for the accommodated disk 10. Therefore, the disk cartridge
 100 shown in FIG. 1 can be loaded in a conventional disk drive unit
 prepared for a disk cartridge accommodating the disk 10 without any
 modification, and then information can be recorded, reproduced, and
 erased. When the opening/closing cover 201 is accommodated in the case
 body 101 completely (FIG. 1), the portions 202a of the disk holding
 members 202 that are curved outwards come into contact with the portions
 of the inner walls 104 where the space between the opposed inner walls 104
 of the disk-storage portion 103 of the case body is widened. Consequently,
 the disk 10 does not come into contact with the disk holding members 202
 even when the disk 10 is rotated in a drive unit.
 Further, the disk holding members 202 are not formed in a continuous shape
 (a circle) surrounding the whole periphery of the disk but with two
 components by cutting an end away. Thus, the disk holding members 202 are
 not present inside the head access opening 180, and therefore a head and
 the disk holding members do not bump together.
 As described above, the disk cartridge of the present invention maintains
 the compatibility with a conventional disk cartridge standardized for an
 accommodated disk. On the other hand, the disk cartridge has a
 configuration in which the accommodated disk can be ejected together with
 the opening/closing cover 201. By loading the disk into the adapter to be
 described later, information can be recorded, reproduced, and erased in a
 drive unit designed for a larger-size disk cartridge.
 In the disk cartridge of the present invention, it is preferable that a
 first locking means is formed for holding and fixing the opening/closing
 cover 201 to the case body 101 at a position where the opening/closing
 cover 201 is accommodated in the case body 101 and covers the opening 102
 completely.
 The first locking means is provided for preventing the opening/closing
 cover 201 from being withdrawn from the case body 101 at an undesired
 time. The first locking means prevents the accommodated disk from being
 exposed accidentally and avoids scratches on the disk and adhesion of dirt
 onto the disk.
 In the case of the disk cartridge according to the present embodiment, the
 first locking means comprises locking holes 105 and first locking
 projections 203. The respective locking holes 105 are formed in the
 vicinity of the opening 102 of the opposed inner walls 104 forming a part
 of the disk-storage portion 103 of the case body. The first locking
 projections 203 are formed in the opening/closing cover 201 so as to
 engage with the locking holes 105 respectively at the position where the
 opening/closing cover 201 is accommodated in the case body 101 and covers
 the opening 102 completely.
 The case body 101 and the opening/closing cover 201 are locked by the first
 locking means as follows. The opening/closing cover 201 is inserted into
 the disk-storage portion 103 of the case body 101 from the state shown in
 FIG. 3. When the first locking projections 203 reach the opening 102 of
 the case body 101, the first locking projections 203 come into contact
 with opening corners of the inner walls 104. Due to slopes formed in the
 contact portion side of the first locking projections 203, hinges 204 are
 elastically deformed inwards. Then, the opening/closing cover 201 is
 further inserted while the first locking projections 203 are in contact
 with the inner walls 104. When the first locking projections 203 reach the
 locking holes 105, the hinges 204 are elastically restored and the first
 locking projections 203 engage with the locking holes 105 to complete the
 lock (FIG. 1).
 On the other hand, the first locking means is unlocked as follows. When the
 disk cartridge locked as shown in FIG. 1 is inserted to a predetermined
 position inside an adapter of the present invention described later, first
 unlocking claws 205 that are elastically displaced together with the first
 locking projections 203 provided at the portions of hinges 204 come into
 contact with a first unlocking means (first unlocking bars 606) of the
 adapter described later. Then, the inclined surfaces formed at the ends of
 the first unlocking means with an acute angle provide external forces to
 both the first unlocking claws 205 in a direction of the inward
 displacement, and the hinges 204 are elastically deformed. As a result,
 the engagement between the first locking projections 203 and the locking
 holes 105 is released.
 In the disk cartridge according to the present embodiment, the locking
 holes 105 are through holes leading to the outside of the case body 101.
 Therefore, it is possible to release the engagement between the first
 locking projections 203 and the locking holes 105 by inserting a pointed
 stick into the through holes from the outside of the case body.
 Further, in the disk cartridge according to the present embodiment, first
 unlocking knobs 206 that are elastically displaced together with the first
 locking projections 203 provided at the portions of the hinges 204 are
 formed so as to be exposed to the outside of the case body in a locked
 state (see FIG. 1). Therefore, by holding both the first unlocking knobs
 206 from the outside toward the inside so as to move toward each other,
 the hinges 204 are elastically deformed, thus releasing the engagement
 between the first locking projections 203 and the locking holes 105.
 Thus, by allowing the first locking means to be unlocked even in the cases
 other than the case where the disk cartridge is inserted into the adapter
 described later, a user can eject an accommodated disk to check, clean or
 change it as required.
 As shown in FIG. 3, it is preferable that the disk cartridge according to
 the present embodiment comprises a second locking means for limiting the
 movement of the opening/closing cover 201 in its withdrawal direction at a
 position where the disk 10 can be ejected by withdrawing the
 opening/closing cover 201 from the case body 101.
 As described above, in the disk cartridge in which a user can unlock the
 first locking means, withdraw the opening/closing cover 201, and eject the
 accommodated disk 10, it is desirable that a safety mechanism for
 preventing the opening/closing cover 201 and the disk 10 from being
 dropped accidentally is provided. The second locking means functions for
 this effectively.
 In the disk cartridge according to the present embodiment, the second
 locking means comprises the locking holes 105 and second locking
 projections 207. The locking holes 105 are formed on the respective
 opposed inner walls 104 in the vicinity of the opening 102. The opposed
 inner walls form a part of the disk-storage portion 103 of the case body.
 The second locking projections 207 are formed at the ends of the disk
 holding members 202 of the opening/closing cover 201 so as to engage with
 the locking holes 105 respectively at the positions where the
 opening/closing cover 201 is withdrawn so that the accommodated disk 10
 can be ejected.
 The second locking means can lock the opening/closing cover 201 in its
 withdrawal direction as follows. When the opening/closing cover 201 is
 withdrawn from the case body 101 from the state shown in FIG. 1, as
 described above, the portions 202a that are curved outwards of the disk
 holding members 202 of the opening/closing cover 201 come into contact
 with the inner walls 104 of the disk-storage portion 103 of the case body
 101, and the opening/closing cover 201 is withdrawn with the portions 202a
 being elastically deformed so as to move toward each other. However, after
 the portions 202a of the disk holding members 202 that are curved outwards
 are drawn out from the case body, the opening/closing cover 201 is
 withdrawn with the second locking projections 207 formed at the ends of
 the disk holding members 202 being in contact with the inner walls 104.
 When the second locking projections 207 reach the locking holes 105, the
 disk holding members 202 are elastically restored. Then, the second
 locking projections 207 engage with the locking holes 105, thus limiting
 the further withdrawal of the opening/closing cover 201 (FIG. 3). Thus, a
 user cannot draw out the opening/closing cover 201 by gathering momentum
 and therefore the opening/closing cover 201 and the disk 10 cannot be
 dropped accidentally.
 On the other hand, the second locking means are unlocked as follows.
 As shown in FIG. 3, when the second locking means functions, by holding
 both the disk holding members 202 from the outside toward the inside so as
 to move toward each other, the disk holding members 202 are elastically
 deformed, thus releasing the engagement between the second locking
 projections 207 and the locking holes 105.
 The second locking projections 207 are provided with a slope so as to have
 an acute angle at their ends as shown in the figure. Therefore, when the
 opening/closing cover 201 is inserted into the opening 102 of the case
 body 101, or when the opening/closing cover 201 is further inserted from
 the state in which the second locking projections 207 and the locking
 holes 105 are engaged with each other as shown in FIG. 3, both the disk
 holding members 202 are easily deformed elastically in the direction
 moving toward each other due to the slope. Consequently, second locking
 projections 207 do not hinder the insertion of the opening/closing cover
 201.
 Further, in the disk cartridge of the present embodiment, the locking holes
 105 are used as both the locking holes engaging with the first locking
 projections 203 and the locking holes engaging with the second locking
 projections 207 as common locking holes. Therefore, the configuration can
 be simplified. Needless to say, there will be no problem even when the
 respective locking holes are provided separately.
 In the disk cartridge of the present embodiment, it is preferable that the
 opening/closing cover 201 can be elastically deformed in the direction
 substantially perpendicular to a disk surface when the movement of the
 opening/closing cover 201 is limited in its withdrawal direction due to
 the function of the second locking means. FIG. 4 shows schematic views
 illustrating the state in which the movement of the opening/closing cover
 is limited in its withdrawal direction by the second locking means in the
 disk cartridge according to the present embodiment having such a
 configuration as described above. FIG. 4(a) is a plan view and FIG. 4(b)
 is a side view thereof. As shown in FIG. 4(b), the disk holding members
 202 can be elastically deformed in the direction substantially
 perpendicular to a surface of the disk 10. Consequently, a user can eject
 the disk 10 easily.
 In the disk cartridge according to the present embodiment, it is preferable
 that third locking means is provided for holding and fixing the
 opening/closing cover 201 to the case body 101 at the position where the
 opening/closing cover 201 is accommodated in the case body 101 completely
 and the opening 102 is covered. Further, it is preferable that the held
 and fixed state of the opening/closing cover 201 by the third locking
 means can be released by applying external force, but the state can be
 released only in an irreversible manner, i.e. once the state is released,
 it is not possible to recover the original state, which differs from the
 case of the first locking means.
 Essentially, it is not desirable for a user to eject a disk accommodated in
 a disk cartridge in order to avoid adhesion of dirt and scratches, which
 is different from a disk having the premise that the disk is handled in a
 bare condition. The disk cartridge of the present embodiment is provided
 with a mechanism for unlocking the first locking means. Only a
 predetermined operation by a user enables the unlocking. However, it may
 be possible even for a user who does not intend to eject the disk to
 unlock the first locking means unintentionally during handling the disk
 cartridge. The third locking means provides a means for preventing the
 first locking means from being unlocked unintentionally. Therefore, the
 third locking mans must not have a configuration in which the third
 locking means can be unlocked unintentionally in an ordinal condition of
 use. In addition, only the application of external force enables the
 unlocking.
 Further, it is preferable that the unlocking of the third locking means can
 be confirmed easily when the third locking means has been released. When
 the unlocking is confirmed in a disk cartridge, it means that a disk
 accommodated in the disk cartridge is exposed to the outside at least once
 by a user. Therefore, a user can surmise easily that the disk may have
 lower reliability of information than that in a disk cartridge in which a
 locking means has not been unlocked. The unlocking of the third locking
 means in this case does not include the unlocking in loading the
 opening/closing cover into the adapter described later. According to the
 present invention, a user can insert the opening/closing cover into the
 adapter without touching a disk at all. Consequently, the decrease in the
 reliability of information recorded on the disk due to the unlocking of
 the third locking means in this case is in an ignorable degree.
 An example of a configuration of such a third locking means will be
 explained with reference to FIGS. 5 and 6. FIG. 5 is a partial
 cross-sectional perspective view showing an enlarged third locking means
 of the opening/closing cover according to the present embodiment. FIG. 6
 shows partial cross-sectional perspective views illustrating an enlarged
 third locking means of the disk cartridge according to the present
 embodiment.
 As shown in FIGS. 5 and 6(a), the third locking means according to the
 present embodiment comprises a third locking hole 106 and a third locking
 projection 209. The third locking hole 106 is formed in the vicinity of
 the opening 102 of the case body 101 so as to go through from an upper
 surface to a lower surface of the case body 101. The third locking
 projection 209 is formed in the opening/closing cover 201 so as to engage
 with the third locking hole 106 at the position where the opening/closing
 cover 201 is accommodated in the case body 101 to cover the opening 102
 completely. More particularly, a lock key 208 is formed at a predetermined
 position in the opening/closing cover 201 via connecting portions 210 so
 as to be combined with the opening/closing cover 201 to be one component
 and so as to project from the upper surface and the lower surface of the
 opening/closing cover 201. The parts projecting from the opening/closing
 cover 201 of the lock key 208 form the third locking projection 209. The
 connecting portions 210 are formed so as to bridge between respective
 substantial centers of four surfaces of the lock key 208 and inner-wall
 faces of the opening/closing cover 208 surrounding the lock key 208 (see
 FIG. 20 described later).
 The third locking means can be unlocked as follows.
 In the state shown in FIG. 6(a), a predetermined external force (shown by
 an arrow F in FIG. 5) is applied so as to push the third locking
 projection 209 positioned within the locking hole 106. As a result, the
 connecting portions 210 are disconnected and therefore the lock key 208 is
 removed to the outside through the third locking hole 106 in the lower
 surface as shown in FIG. 6(b), thus unlocking the third locking means. In
 FIG. 6(b), a numeral 210' indicates disconnected surfaces of the
 connecting portions 210. Further, by unlocking the first locking means, it
 is possible to draw out the opening/closing cover 201 from the case body
 101 as shown in FIG. 7.
 When the third locking means is unlocked as described above, the lock key
 208 is removed to the outside. Therefore, it is not possible to recover
 the state before the unlocking. In addition, when the opening/closing
 cover 201 is accommodated in the case body 101, the third locking
 projection is not present within the third locking hole 106 and therefore
 it is possible to see the opposite side through the third locking hole
 106. Consequently, a user can easily confirm that the third locking means
 has been unlocked before.
 The unlocking of the third locking projection is also possible in a
 reversible manner by fitting a convex part (a third unlocking projection
 607) of the third unlocking means of the adapter according to the present
 invention described later into a concave part 213 formed in the vicinity
 of the third locking means without using the above-mentioned irreversible
 means in which the lock key 208 is removed.
 It is preferable to provide an erroneous-insertion preventing means so that
 the opening/closing cover 201 is inserted into the case body 101 with the
 correct orientation when being inserted into the disk-storage portion 103
 of the case body 101 again after having been drawn out from the case body
 101 as described above. It is preferable that the erroneous-insertion
 preventing means is formed so that the opening/closing cover 201 cannot be
 inserted into the opening 102 of the case body 101 at all when the
 opening/closing cover 201 is inserted with wrong orientation or even if
 the opening/closing cover 201 can be inserted into the opening 102 to some
 extent, the opening/closing cover 201 cannot be inserted into the case
 body 101 completely, thus finding out the insertion with wrong orientation
 easily.
 The means for preventing the erroneous insertion of the opening/closing
 cover into the case body in the disk cartridge according to the present
 embodiment is formed of engagement members comprising notches 107 and 108
 provided on the end faces of the opening 102 of the case body 101 and
 erroneous-insertion preventing projections 211 and 212 provided at
 predetermined positions of the opening/closing cover 201 as shown in FIG.
 2.
 When the opening/closing cover 201 is inserted into the case body 101 with
 correct orientation, the notches 107 and 108 engage with the
 erroneous-insertion preventing projections 211 and 212, respectively.
 Thus, as shown in FIG. 1, the opening/closing cover 201 is accommodated in
 the case body 101 completely and covers the opening 102.
 On the other hand, when the opening/closing cover 201 is inserted into the
 case body 101 upside down with respect to the opening/closing cover 201,
 the insertion of the opening/closing cover 201 is possible to some extent,
 but the opening/closing cover 201 cannot be accommodated in the case body
 101 completely as shown in FIG. 8 due to the difference in depth between
 the notches 107 and 108. Thus, a user can easily notice the insertion with
 wrong orientation.
 In the example described above, the engagement members are formed in
 asymmetrical shapes with respect to the center line of the case body in
 the insertion direction of the opening/closing cover 201 into the
 disk-storage portion. However, the erroneous-insertion preventing means is
 not limited to this. For instance, the engagement members may be formed at
 asymmetrical positions with respect to the center line.
 The disk cartridge of the present invention is inserted into the adapter
 described later to be used. In this case, it is preferable to provide a
 means for preventing erroneous insertion of the disk cartridge into the
 adapter so that the disk cartridge can be inserted with correct
 orientation.
 It is preferable that such an erroneous-insertion preventing means is
 formed so that the cartridge cannot be inserted into the adapter at all
 when being inserted with wrong orientation, or even if the cartridge can
 be inserted into the adapter to some extent, the cartridge cannot be
 inserted to a predetermined position, thus easily finding out the
 insertion with wrong orientation.
 The means for preventing erroneous insertion of the disk cartridge into the
 adapter according to the present embodiment comprises a concave part 213
 formed on the leading end face of the disk cartridge in the insertion
 direction into the adapter as shown in FIG. 1 and at an asymmetrical
 position with respect to the center line in the insertion direction and a
 convex part (the erroneous-insertion preventing projection 607) formed
 inside the insertion portion of the adapter that engages with the concave
 part 213.
 When the disk cartridge 100 is inserted into the adapter described later
 with correct orientation, the convex part formed inside the insertion
 portion of the adapter engages with the concave part 213 formed on the
 leading end face of the disk cartridge 100 in the insertion direction.
 Thus, the cartridge 100 can be inserted to a predetermined position in the
 adapter reliably. On the other hand, when the disk cartridge 100 is
 inserted into the adapter upside down, the insertion of the disk cartridge
 100 is possible to some extent, but the convex part formed inside the
 insertion portion of the adapter comes into contact with the leading end
 face of the disk cartridge 100 in the insertion direction and therefore
 further insertion of the disk cartridge 100 is not possible. Thus, a user
 can notice easily that the disk cartridge is inserted upside down.
 In the example described above, the concave part is formed at the
 asymmetrical position with respect to the center line of the disk
 cartridge in the insertion direction. However, the erroneous-insertion
 preventing means is not limited to this. For example, in the
 erroneous-insertion preventing means, the concave part may be formed in an
 asymmetrical shape with respect to the center line in the insertion
 direction.
 Further, it is preferable that the space between the ends of the pair of
 disk holding members 202 is smaller than a disk diameter in order to
 prevent the disk 10 from falling off from the opening of the insertion
 portion of the adapter accidentally when the opening/closing cover 201 and
 the disk 10 are loaded in the insertion portion of the adapter by the
 method described later and the door of the adapter is not closed (see FIG.
 19).
 Moreover, hooks 214 that engage with an opening/closing-cover holding means
 of the adapter described later are formed in the opening/closing cover
 201.
 Second Embodiment
 Next, a disk cartridge according to a second embodiment of the present
 invention will be explained. FIG. 9 is a schematic perspective view
 showing the appearance of an example of the disk cartridge according to
 the second embodiment of the present invention. FIG. 10 is an exploded
 perspective view showing schematic shapes of the main components of the
 disk cartridge shown in FIG. 9. FIG. 11 is a schematic plan view showing a
 state during the assembly of the disk cartridge shown in FIG. 9 or a state
 in which an opening/closing cover is withdrawn.
 In FIGS. 9-11, a numeral 300 indicates a disk cartridge according to the
 present embodiment, and numerals 301 and 401 indicate a case body and an
 opening/closing cover, respectively. Other members having the same
 function as in the first embodiment are indicated with the same characters
 as in the first embodiment. The explanations for them are omitted here to
 avoid duplicate explanations.
 The disk cartridge according to the second embodiment is different from the
 disk cartridge according to the first embodiment in that the former is
 designed assuming the case where a user ejects an accommodated disk by
 himself and on the other hand the latter is not designed assuming such a
 case. That is to say, in the disk cartridge according to the second
 embodiment, by avoiding the case where a user ejects an accommodated disk
 by himself, the possibility of scratching the disk or adhesion of foreign
 objects onto the disk is eliminated to the utmost, thus obtaining high
 reliability of recorded information and high durability of the disk.
 Thus, in the disk cartridge according to the first embodiment, the
 components provided assuming the case where a user ejects the accommodated
 disk by himself are eliminated in the disk cartridge according to the
 second embodiment. Except for those components, the disk cartridge
 according to the second embodiment has the same configuration as that of
 the disk cartridge according to the first embodiment.
 The components eliminated in the disk cartridge according to the second
 embodiment are those relating to the unlocking of the first locking means,
 those relating to the second locking means, and those relating to the
 third locking means in the disk cartridge according to the first
 embodiment. Those will be explained sequentially as follows.
 The disk cartridge according to the second embodiment does not comprise
 some of the components relating to the unlocking of the first locking
 means of the disk cartridge according to the first embodiment. That is,
 the disk cartridge according to the second embodiment does not have first
 unlocking knobs (the first unlocking knobs 206 in the first embodiment)
 that are elastically deformed together with the first locking projections
 203 provided at the portions of the hinges 204. In the disk cartridge
 according to the second embodiment, locking holes 105 are through holes
 leading to the outside of a case body. Consequently, it is possible to
 release the engagement between the first locking projections 203 and the
 locking holes 105 by inserting a pointed stick into the through holes from
 the outside of the case body in emergency.
 The disk cartridge according to the second embodiment does not comprise the
 components relating to the second locking means included in the disk
 cartridge according to the first embodiment. That is, the disk cartridge
 according to the second embodiment does not have second locking
 projections (the second locking projections 207 in the first embodiment)
 engaging with the locking holes 105 provided at the ends of disk holding
 members 202 of an opening/closing cover 201. Since it is not assumed that
 a user draws out the opening/closing cover 201 by himself, it is not
 necessary to provide a safety mechanism for preventing the opening/closing
 cover 201 and an accommodated disk 10 from being dropped accidentally.
 The disk cartridge according to the second embodiment does not comprise the
 components relating to the third locking means included in the disk
 cartridge according to the first embodiment. That is to say, the disk
 cartridge according to the second embodiment does not have the third
 locking hole 106, the third locking projection 209 engaging with the third
 locking hole 106, the lock key 208 forming the third locking projection
 209, and the connecting portions 210 connecting the opening/closing cover
 201 and the lock key 208 included in the disk cartridge according to the
 first embodiment. In the present embodiment, since the first unlocking
 knobs 206 are not provided, it is not assumed that a user unlocks the
 first locking means accidentally in an ordinary condition of use.
 The configurations other than those described above in the present
 embodiment are the same as those in the previously described first
 embodiment. Therefore, detailed explanation of the present embodiment is
 omitted except for those described above.
 Third Embodiment
 An adapter according to the third embodiment of the present invention will
 be explained.
 The method of using the adapter according to the third embodiment of the
 present invention will be described as follows. When a user inserts the
 disk cartridge described in the first or second embodiment into the
 adapter according to the third embodiment, the disk is shifted into the
 adapter. The adapter has compatibility in external shape with a larger
 disk cartridge than the disk cartridge described in the first and second
 embodiments. Therefore, by loading the adapter accommodating the disk that
 has been shifted into the adapter into a drive unit that is suitable for
 the adapter, it is possible to record information on the disk or to read
 out or erase recorded information from the disk. That is, needless to say,
 when a user has a drive unit designed for the disk cartridge having
 compatibility in external shape with the adapter according to the third
 embodiment of the present invention, recording, reproduction and erasure
 of information are possible by loading a disk cartridge suitable for the
 drive unit into the drive unit. In addition, when using the adapter
 according to the third embodiment of the present invention, information
 can be recorded, reproduced, and erased by loading a disk accommodated in
 a smaller disk cartridge into the drive unit via the adapter.
 Moreover, the disk can be shifted into the adapter without being touched
 directly by a user. Therefore, the possibility of adhesion of foreign
 objects onto the disk or scratching the disk can be avoided, thus securing
 the reliability of information and durability of the disk.
 The adapter according to the third embodiment of the present invention will
 be explained with reference to the drawings as follows.
 FIG. 12 is an entire perspective view showing the appearance of an example
 of the adapter according to the third embodiment of the present invention.
 FIG. 13 is a schematic plan view showing the internal structure after
 removing an upper case and a shutter of the adapter shown in FIG. 12. FIG.
 14 is an exploded schematic perspective view showing components (except
 for the upper case and the shutter) of the adapter shown in FIG. 12.
 An adapter 500 of the present embodiment is formed by engaging an upper
 case 501 and a lower case 601 with each other. The adapter 500 comprises
 an insertion portion 602 to be a space where a disk cartridge is inserted.
 The insertion portion 602 is surrounded by inner walls of the upper case
 501 and the lower case 601, a pair of opposed guide walls 604, and a pair
 of contact walls 605 formed on the lower case. Further, a door 510 capable
 of being opened and closed is provided at the entrance of the insertion
 portion 602. Head access openings 502 and 603 are formed in the upper case
 501 and the lower case 601 respectively in order to allow a disk surface
 to be scanned by a head for recording information on or reproducing or
 erasing recorded information from a disk accommodated in the adapter. The
 adapter 500 further comprises a shutter 503 for covering the head access
 openings and an elastic spring (not shown in the figures) for maintaining
 the shutter 503 in a closed state when the adapter is not loaded on the
 drive unit.
 An outline of a method of loading a disk into the adapter according to the
 third embodiment of the present invention will be explained using FIGS.
 15-19 as follows. The disk cartridge shown in the figures is the one
 explained in the first embodiment. Needless to say, the adapter of the
 present embodiment also can be used for the disk cartridge described in
 the second embodiment.
 The disk cartridge 100 described in the above embodiment is inserted into
 the insertion portion 602 with the entrance 102 of the case body 101
 facing forward after the door 510 is opened (FIG. 15).
 The disk cartridge 100 is guided by the opposed guide walls 604 and the
 respective inner walls of the upper case 501 and the lower case 601 and is
 inserted to the vicinity of a position where its end face comes into
 contact with the contact walls 605 (FIG. 16). Then, a first unlocking
 means operates for unlocking the first locking means that holds and fixes
 the opening/closing cover 201 of the disk cartridge to the case body 101,
 resulting in the state in which the opening/closing cover 201 can be
 withdrawn from the case body 101. In the case of the disk cartridge
 according to the first embodiment having the third locking means, the
 third locking means is unlocked in a reversible manner by a third
 unlocking means provided in the adapter 500. Further, the opening/closing
 cover 201 under such a state is retained in the adapter by an
 opening/closing-cover holding means provided in the adapter 500. The
 opening/closing-cover holding means maintains the opening/closing cover
 201 at a predetermined position in the insertion portion 602 even after
 the case body 101 has been drawn out. In this case, the disk 10
 accommodated in the disk cartridge 100 is drawn out from the case body 101
 together with the opening/closing cover 201 by the pair of disk holding
 members 202 provided in the opening/closing cover 201, thus remaining
 inside the insertion portion 602 of the adapter.
 Then, the case body 101 is drawn out from the insertion portion 602. In the
 case of the disk cartridge according to the first embodiment having the
 second locking means, the second locking means is unlocked by a second
 unlocking means provided in the adapter 500 (FIG. 17). Consequently, it is
 possible to separate the case body 101 and the opening/closing cover 201
 completely.
 The opening/closing cover 201 and the disk 10 held by the opening/closing
 cover 201 are left in the insertion portion 602, and the case body 101 is
 drawn out from the insertion portion 602 completely (FIG. 18). Then, the
 door 510 is closed (FIG. 19).
 Thus, when the adapter 500 is loaded in a drive unit designed for a disk
 cartridge having compatibility in external shape with the adapter, it is
 possible to record information on or reproduce or erase recorded
 information from the disk accommodated in the adapter.
 The configuration and function of the above will be explained sequentially
 as follows.
 The first unlocking means of the present invention comprises a pair of
 first unlocking bars 606 formed on the contact walls 605 as shown in FIG.
 13. The first unlocking bars 606 are provided at the positions coming into
 contact with the pair of first unlocking claws 205 (see FIG. 3) formed on
 the end face of the opening/closing cover 201 when the disk cartridge is
 inserted into the insertion portion 602. The points of the first unlocking
 bars 606 have a slope with an acute angle. Therefore, the slopes with an
 acute angle provided at the points of the first unlocking bars 606 come
 into contact with the slopes with an acute angle provided at the points of
 the first unlocking claws 205, which generates external force so as to
 displace the pair of first unlocking claws 205 inwards. As a result, the
 portions of hinges 204 are elastically deformed (see FIG. 17), and then
 the first locking projections 203 are displaced together with the first
 unlocking claws 205, thus releasing the respective engagement between the
 first locking projections 203 and the locking holes 105.
 The first unlocking means of the present invention is a required element
 for separating the opening/closing cover from the case body by unlocking
 the lock in a disk cartridge having the first locking means as in the
 first and second embodiments.
 Next, the third unlocking means of the adapter according to the third
 embodiment of the present invention will be explained.
 The third unlocking means is a required element for separating the
 opening/closing cover from the case body by unlocking the lock in the disk
 cartridge having the third locking means according to the first embodiment
 of the present invention. It is necessary to unlock the third locking
 means by the third unlocking means in a reversible manner, which is
 different from the irreversible method of removing the lock key 208
 described above.
 The third unlocking means of the present invention is formed of a third
 unlocking projection 607 formed on the contact wall 605 as shown in FIG.
 13.
 FIG. 20 shows partially enlarged views for explaining an operating state of
 the third unlocking means of the present invention. FIG. 20(a) is a
 partial cross-sectional view taken on a plane that is perpendicular to a
 disk surface and passes through the center of the third unlocking
 projection 607. FIG. 20(b) is a cross-sectional view taken on line I-I in
 the arrow direction of FIG. 20(a). FIG. 20(c) is a cross-sectional view
 taken on line II--II in the arrow direction of FIG. 20(a).
 The third unlocking projection 607 is positioned on the contact wall 605
 and at the position where the third unlocking projection 607 fits into a
 concave part 213 formed in the vicinity of the third locking means on the
 end face of the opening/closing cover 201 when a disk cartridge is
 inserted into the insertion portion 602. The third unlocking projection
 607 has a slope formed so that its point is narrower than its bottom as
 shown in FIG. 20(a). More particularly, the third unlocking projection 607
 is formed so that a width d1 of the point in the direction perpendicular
 to the disk surface is narrower than the distance between the inner walls
 of the case body 101, and a width d2 of the bottom is wider than a length
 of the lock key 208. Therefore, when the disk cartridge is inserted into
 the insertion portion 602, the point of the third unlocking projection 607
 is inserted into the concave part 213. When the disk cartridge is further
 inserted, the inner walls of the case body of the disk cartridge are
 elastically deformed by the bottom of the third unlocking projection 607
 so as to increase the distance between the inner walls. In this case, the
 distance between the pair of locking holes 106 formed in the vicinity of
 the concave part 213 of the case body 101 also is increased and exceeds
 the length of the lock key 208 at last. Consequently, the engagement
 between the locking holes 106 and the lock key 208 is released, thus
 unlocking the third locking means (see FIGS. 20(a) and (c)).
 As described above, the third locking means is unlocked by the third
 unlocking means utilizing the elastic deformation of the case body 101.
 Therefore, the unlocking does not cause disconnection of the connecting
 portions 210 connecting the lock key 208 and the opening/closing cover
 201, resulting in the unlocking in a reversible manner.
 Next, a means for preventing erroneous insertion of the disk cartridge
 according to the third embodiment of the present invention will be
 explained.
 It is preferable that a means for preventing erroneous insertion of the
 disk cartridge is provided for the adapter of the present invention. When
 the means is provided for the adapter, a user cannot insert the disk
 cartridge with wrong orientation at all or the disk cartridge cannot be
 inserted to a predetermined position even when being inserted to some
 extent. Thus, the insertion with wrong orientation can be found easily.
 The means for preventing erroneous insertion of the disk cartridge into
 the adapter according to the present embodiment is formed of an
 erroneous-insertion preventing projection 607 and the concave part 213.
 The projection 607 is formed on the contact wall 605 at an asymmetrical
 position with respect to the center line of the disk cartridge in the
 insertion direction into the adapter. The concave part 213 is formed on
 the leading end face in the insertion direction of the disk cartridge so
 that the projection 607 fits into the concave part 213 when the disk
 cartridge is inserted with correct orientation.
 In the present embodiment, the erroneous-insertion preventing projection
 607 also has a function as the third unlocking projection 607 described
 above. However, needless to say, those may be provided separately.
 When the disk cartridge is inserted into the insertion portion 602 with
 correct orientation, the erroneous-insertion preventing projection 607
 formed inside the insertion portion of the adapter is engaged with the
 concave part 213 formed on the leading end face of the disk cartridge in
 its insertion direction, thus securing the insertion of the disk cartridge
 to the predetermined position in the adapter (FIG. 16).
 On the other hand, when the disk cartridge is inserted into the adapter
 upside down, the insertion of the disk cartridge is possible to some
 extent. However, the erroneous-insertion preventing projection 607 formed
 inside the insertion portion of the adapter comes into contact with the
 leading end face of the disk cartridge in its insertion direction.
 Therefore, the disk cartridge cannot be inserted any further. Thus, a user
 can easily recognize the insertion with wrong orientation.
 In the example described above, the erroneous-insertion preventing
 projection is formed at an asymmetrical position with respect to the
 center line of the disk cartridge in its insertion direction. However, the
 erroneous-insertion preventing means is not limited to this. For example,
 the erroneous-insertion preventing projection may be formed in an
 asymmetrical shape with respect to the center line in the insertion
 direction.
 Next, an opening/closing-cover holding means of the adapter according to
 the third embodiment of the present invention will be explained.
 The opening/closing-cover holding means of the present invention has a
 function of retaining the opening/closing cover 201 inside the insertion
 portion 602 of the adapter after the release of the engagement with the
 case body 101 by the first unlocking means and the third unlocking means
 described above and maintaining the opening/closing cover 201 at the
 predetermined position inside the insertion portion 602 even after the
 case body 101 has been drawn out.
 As shown in FIGS. 13 and 14, the opening/closing-cover holding means
 comprises an opening/closing cover holding plate 701 that has holding
 hooks 702 and is maintained in the lower case 601 movably to the right and
 left on the paper showing FIG. 13 via guide pins 608, and a tensile spring
 703 that provides force to the plate 701 in one direction (in the right
 direction on the paper showing FIG. 13) by its elasticity. The holding
 hooks 702 are provided at positions corresponding to the hooks 214 (see
 FIG. 3) formed on the end face of the opening/closing cover 201 when the
 disk cartridge is inserted into the insertion portion 602. As shown in
 FIG. 13, the point of each holding hook 702 has a slope formed with an
 acute angle. Therefore, when the disk cartridge is inserted into the
 insertion portion 602, first the slopes of the points of the holding hooks
 702 come into contact with the ends of the hooks 214 of the
 opening/closing cover 201. When the disk cartridge is further inserted,
 the slopes of the points of the holding hooks 702 move the plate 701 to
 the left on the paper showing FIG. 13. Then the plate 701 is pulled back
 by the tensile spring 703, and thus the holding hooks 702 and the hooks
 214 engage with each other. Concurrently with this, both the first locking
 means and the third locking means are unlocked. Therefore, even if the
 case body 101 is withdrawn from the insertion portion 602 after that, the
 opening/closing cover 201 is retained inside the insertion portion 602
 (FIG. 17).
 It is desirable that the opening/closing cover 201 held by the
 above-mentioned plate 701 is maintained at a predetermined position inside
 the insertion portion 602 stably. In the case where the opening/closing
 cover 201 is freely movable inside the insertion portion 602, the
 opening/closing cover 201 comes into contact with the disk in some cases
 when the adapter is loaded in a drive unit and the disk is rotated. It
 also is desirable to maintain the relative position of the opening/closing
 cover 201 and the lower case 601 invariably and constantly in order to
 secure the function of the second unlocking means described later. In
 order to realize this, the adapter according to the third embodiment has a
 means for holding the opening/closing cover stably.
 As shown in FIGS. 13 and 14, the means for holding the opening/closing
 cover stably comprises a press-rotating member 711 that is held on the
 lower case 601 rotatably around a guide pin 608 as its rotation center,
 and a tensile spring 713 providing force to the press-rotating member 711
 in one direction by its elasticity. Two pairs of each member are provided.
 The press-rotating member 711 has a press portion 712 at an end. When the
 disk cartridge is inserted into the insertion portion 602, the press
 portion 712 comes into contact with the end face of the opening/closing
 cover 201 and presses the opening/closing cover 201 with the tensile
 elasticity of the tensile spring 713 in the direction (in the upper
 direction on the paper showing FIG. 13) of removing the opening/closing
 cover 201 from the insertion portion 602. The opening/closing cover 201 is
 maintained stably at the predetermined position inside the insertion
 portion 602 by the pressure provided by the press portion 712 and the
 opening/closing-cover holding means (see FIGS. 17-19).
 When the opening/closing cover 201 is drawn out together with the case body
 as described later, the means for holding the opening/closing cover
 stably, which will be explained in detail later, provides the effects that
 the unlocked state of the opening/closing-cover holding means can be
 recognized clearly and that the opening/closing cover 201 can be drawn out
 easily.
 Next, the second unlocking means of the adapter according to the third
 embodiment of the present invention will be explained.
 The second unlocking means is a required element for separating the
 opening/closing cover from the case body completely by preventing the
 second locking means from functioning in the disk cartridge of the first
 embodiment of the present invention having the second locking means.
 As shown in FIGS. 13 and 14, the second unlocking means of the present
 invention comprise elastic bars 610 and second unlocking projections 609.
 The elastic bars 610 are formed continuously to the guide walls 604 and
 are connected to the lower case 601 indirectly via the guide walls 604.
 The second unlocking projections 609 are formed at the points of the
 elastic bars 610 so as to have a projection toward the insertion portion
 602.
 Since the second unlocking projections 609 project toward the insertion
 portion 602, the second unlocking projections 609 come into contact with
 side walls of the case body 101 of a disk cartridge when the disk
 cartridge is inserted. Thus, the elastic bars 610 are elastically deformed
 so as to move away from the insertion portion 602. As shown in FIG. 16,
 the second unlocking projections 609 are formed at positions opposing the
 second locking projections 207 formed in the opening/closing cover 201 via
 the side walls of the case body 101 when the opening/closing cover 201 is
 stably maintained by the opening/closing-cover holding means.
 After that, when the case body 101 is withdrawn from the insertion portion
 602 in the state in which the opening/closing cover 201 is maintained by
 the opening/closing-cover holding means, the second unlocking projections
 609 fit into the locking holes 105 that are formed in the side walls of
 the case body 101 (FIG. 17). At the same time, the second locking
 projections 207 formed in the opening/closing cover 201 also are apt to
 fit into the locking holes 105. However, it is designed so that the
 elastic restoring moment of the elastic bars 610 is stronger than that of
 the disk holding members 202 of the opening/closing cover. Therefore,
 since the second locking projections 207 are pushed by the second
 unlocking projections 609, the second locking projections 207 cannot fit
 into the locking holes 105. Each second unlocking projection 609 has
 slopes on both sides in the moving direction of the locking holes 105 as
 shown in the figure. Therefore, when the case body 101 is further pulled
 from the insertion portion 602 in this state, the slopes of the second
 unlocking projections 609 come into contact with the edges of the locking
 holes 105. Thus, the elastic bars 610 are elastically deformed, and the
 second unlocking projections 609 are moved so as to escape to the outside
 of the insertion portion 602. Therefore, the case body 101 can be drawn
 out from the insertion portion 602 successively.
 As described above, the second unlocking means acts so as to prevent the
 second locking means from functioning.
 Next, the door 510 provided for the adapter according to the third
 embodiment of the present invention will be explained.
 It is preferred to provide the door 510 that closes the opening of the
 insertion portion 602 to prevent the ingress of dust and to prevent the
 accommodated disk from falling off accidentally after loading the disk 10
 into the adapter 500 and drawing out the case body 101 as described above.
 In this case, when the door 510 can be closed even if a user forgets to
 draw out the case body 101 after inserting the disk cartridge into the
 insertion portion 602, i.e. even in the state shown in FIG. 16, it is
 possible for the user to load the adapter into a drive unit without
 drawing out the case body accidentally. In this case, it is possible that
 a head of the drive unit, a disk drive unit, and the like bump into the
 case body 101 and a shutter 181 that are left in the insertion portion,
 thus damaging the drive unit, the adapter, the case body, the disk, and
 the like.
 Therefore, it is preferable that the door 510 has a configuration in which
 the door 510 cannot be closed when the case body 101 is inserted in the
 insertion portion 602. Further, it is more preferable that the door 510 is
 provided so that the external shape of the adapter 500 has compatibility
 with a corresponding disk cartridge in the state in which the door 510 is
 closed completely and so that the adapter 500 cannot be loaded into the
 drive unit when the door 510 is opened.
 As shown in FIG. 14, the door 510 according to the present embodiment is
 provided pivotably upon a pivot 513 as the pivot center that is supported
 by the upper case 501 (not shown in FIG. 14) and the lower case 601. The
 door 510 comprises a door hook 511 and a contact surface 512. The door
 hook 511 is formed so as to hold the door 510 to the upper case 501 (not
 shown in FIG. 14) and the lower case 601 when the door 510 is completely
 closed. The contact surface 512 is formed so as to come into contact with
 a side face of the case body when the case body is inserted in the
 insertion portion 602.
 As shown in FIG. 19, after the disk 10 is accommodated in the adapter 500
 and the case body is drawn out, the door 510 can be closed completely and
 the door hook 511 retains the door 510 to the upper case 501 (not shown in
 FIG. 19) and the lower case 601. Thus, the ingress of dust into the
 insertion portion 602 and accidental falling of the accommodated disk 10
 can be avoided.
 On the other hand, when the door 510 is closed while the case body 101 is
 left inside the insertion portion 602, the contact surface 512 comes into
 contact with one side face of the case body 101 and therefore the door 510
 cannot be closed as shown in FIG. 21. Thus, a user can notice that he has
 forgotten to draw out the case body 101. Further, when the door 510 cannot
 be closed completely, the compatibility in external shape with a
 corresponding disk cartridge cannot be secured. Therefore, under this
 state the adapter cannot be loaded in some drive units. Thus, the
 possibility of accidentally damaging the drive unit, the adapter, the case
 body, the disk, and the like can be avoided.
 Moreover, it is preferable that the adapter of the present invention is
 formed so that the state inside the insertion portion 602, particularly at
 least a part can be identified from the outside. In this case, the
 existence of a disk inside the insertion portion 602, the type of the
 disk, and the like can be identified. As such an identification means, an
 identification window may be provided at a suitable position in the upper
 case 501 and/or the lower case 601, and a part of or the whole part of the
 upper case 501 and/or the lower case 601 may be formed of a transparent
 member.
 Next, an outline of a method of ejecting a disk accommodated in the adapter
 according to the third embodiment of the present invention will be
 explained.
 The case body 101 is inserted into the insertion portion 602 (FIG. 17)
 after opening the door 510 (FIG. 18) from the state shown in FIG. 19. The
 disk 10 and the opening/closing cover 201 are inserted into the
 disk-storage portion 103 of the case body 101 sequentially. The case body
 101 is inserted into the insertion portion 602 until the disk 10 and the
 opening/closing cover 201 are accommodated in the disk-storage portion 103
 completely (FIG. 16).
 When the opening/closing cover 103 is accommodated in the disk-storage
 portion 103 of the case body 101 completely, the first locking means of
 the disk cartridge is ready for functioning. That is to say, the locking
 holes 105 oppose the first locking projections 203 as described with
 reference to FIGS. 1-3. In the disk cartridge of the first embodiment
 having the third locking means, the third locking hole 106 opposes the
 third locking projection 209, thus making the third locking means ready
 for functioning.
 In this condition, the engagement between the opening/closing cover 201 and
 the opening/closing-cover holding means is released by a means for
 releasing the opening/closing-cover holding means.
 Thus, the first locking means and the third locking means operate, and the
 opening/closing cover 201 and the disk 10 can be removed to the outside
 together with the case body 101 (FIG. 15).
 The configuration and function of the above will be explained sequentially
 as follows.
 First, a means for releasing the opening/closing-cover holding means of the
 adapter according to the third embodiment of the present invention will be
 explained.
 The means for releasing the opening/closing-cover holding means is used for
 releasing the engagement between the opening/closing cover 201 and the
 opening/closing-cover holding means, i.e. the engagement between the hooks
 214 of the opening/closing cover 201 and the holding hooks 702 of the
 opening/closing cover holding plate 701. The means for releasing the
 opening/closing-cover holding means is used for drawing out the
 opening/closing cover from the adapter of the present invention having the
 opening/closing-cover holding means and is a required element in the
 adapter of the present invention.
 As shown in FIGS. 13 and 14, the means for releasing the
 opening/closing-cover holding means comprises a bar 731 releasing the
 opening/closing cover holding means, a compression coil spring 735, and a
 release pin 704. The bar 731 is held to the lower cover 601 by two guide
 pins 611 fixed to the lower cover 601 and two fixing rings 612 so as to be
 movable up and down on the paper showing FIG. 13. The compression coil
 spring 735 provides force to the bar 731 in one direction (upward on the
 paper showing FIG. 13) by its elasticity. The release pin 704 is provided
 at an end of the plate 701.
 At one end of the bar 731, an operating lever 732 is provided. When the
 door 510 is closed, the operating lever 732 is housed in the inside
 surrounded by the door 510, the upper case 501, and the lower case 601
 (FIG. 19). Therefore, a user cannot touch the operating lever 732. On the
 other hand, when the door 510 is opened, the operating lever 732 is
 exposed through the opening of the insertion portion 602. Therefore, a
 user can operate the operating lever (FIG. 18). Further, in a normal
 condition a part of the operating lever 732 is in contact with a part of
 the inner wall of the lower cover 601 with the bar 731 being pressed and
 fixed by the elasticity of the compression coil spring 735.
 At the other end of the bar 731, a slope guide 733 is formed. The slope
 guide 733 is formed so as to come into contact with the release pin 704
 provided at an end of the opening/closing cover holding plate 701 when a
 user operates the operating lever 732 to push the bar 731 in a
 longitudinal direction (downward on the paper showing FIG. 13).
 The means for releasing the opening/closing-cover holding means is operated
 as follows.
 The operating lever 732 of the bar 731 is operated so as to be forced
 downward on the paper showing FIG. 16 when the opening/closing cover 201
 is inserted into the disk-storage portion 103 of the case body 101
 completely and the first locking means of the disk cartridge functions
 (FIG. 16). Then, as shown in FIG. 22, the slope guide 733 formed at the
 other end of the bar 731 comes into contact with the release pin 704
 provided at an end of the plate 701, and the release pin 704 and the plate
 701 combined with the release pin 704 are moved to the left on the paper
 showing FIG. 22. As a result, the engagement between the hooks 214 of the
 opening/closing cover 201 and the holding hooks 702 of the plate 701 is
 released.
 In the adapter of the present embodiment, due to the above-mentioned means
 for holding the opening/closing cover stably, a user can clearly notice
 the above-mentioned operation of the means for releasing the
 opening/closing-cover holding means, and the disk cartridge can be drawn
 out further easily.
 Before the release of the opening/closing-cover holding means, the
 opening/closing cover 201 is pressed and fixed by the press portion 712 of
 the press-rotating member 711 by the tensile elasticity of the tensile
 spring 713 with the opening/closing cover 201 being engaged with the
 holding hooks 702 of the opening/closing cover holding plate 701 (FIG.
 16). Therefore, when the engagement between the hooks 214 of the
 opening/closing cover 201 and the holding hooks 702 of the plate 701 (FIG.
 22) is released, the opening/closing cover 201 is pushed out from the
 insertion portion 602 in the ejection direction by the tensile elasticity
 of the tensile spring 713. Thus, the cartridge combined with the
 opening/closing cover 201 to be one component is moved to the ejection
 direction. Consequently, a user can notice the operation of the means for
 releasing the opening/closing-cover holding means, and the disk cartridge
 can be drawn out more easily since one end of the disk cartridge is
 exposed through the opening of the insertion portion 602.
 When the engagement between the hooks 214 of the opening/closing cover 201
 and the holding hooks 702 of the plate 701 is released and then the
 opening/closing cover 201 is pushed out from the insertion portion 602 to
 the outside, the hinges 204 of the opening/closing cover 201 recover their
 elasticity at the same time. Thus, the first locking projections 203 are
 engaged with the locking holes 105. In the disk cartridge of the first
 embodiment, the elastic deformation of the case body 101 around the third
 locking hole 106 is recovered, and thus the third locking projection 209
 is engaged with the third locking hole 106. As a result, the case body 101
 is combined with the opening/closing cover 201 to be one component, and
 they can be drawn out from the adapter 500.
 On the other hand, when a user operates the means for releasing the
 opening/closing-cover holding means accidentally when the case body is not
 inserted in the insertion portion 602, i.e. in the state as shown in FIG.
 18, there is a possibility that the user drops the exposed disk 10 from
 the insertion portion 602 accidentally. When the above-mentioned means for
 holding the opening/closing cover stably has a strong ejection power, it
 also is possible that the disk 10 springs out from the insertion portion
 602 with great force (the disk 10 has a small mass since the disk 10 is
 not accommodated in the case body), which is a bigger problem. Therefore,
 in such a case, it is desirable to provide a safety mechanism of
 prohibiting the operation of the means for releasing the
 opening/closing-cover holding means.
 In this point of view, the adapter according to the present embodiment has
 a means for locking the means for releasing the opening/closing-cover
 holding means.
 As shown in FIGS. 13 and 14, the means for locking the means for releasing
 the opening/closing-cover holding means of the present embodiment
 comprises a disk-positioning member 751a, a fixed pin 614, a torsion coil
 spring 760, and a notch 734. The disk-positioning member 751a is
 maintained pivotably upon a supporting axis 613 fixed to the lower case
 601 as a pivot center and has a locking projection 756 at one end. The
 fixed pin 614 is fixed to the lower case 601 and regulates the pivot of
 the disk-positioning member 751a by the contact with a part of the
 disk-positioning member 751a. The torsion coil spring 760 is engaged with
 a spring hook 755 of the disk-positioning member 751a and the lower case
 601 and presses and fixes the disk-positioning member 751a to the fixed
 pin 614 by its elasticity. The notch 734 is formed on one side of the bar
 731 so as to engage with the locking projection 756 of the
 disk-positioning member 751a.
 The operation of the means for locking the means for releasing the
 opening/closing-cover holding means with such a configuration will be
 explained.
 As shown in FIG. 18, when the opening/closing cover 201 and the disk 10 are
 loaded into the adapter, the disk-positioning member 751a is pressed and
 fixed to the fixed pin 614 by the coil spring 760. FIG. 23 is a partially
 enlarged perspective view of the disk-positioning member 751a in this
 state. FIG. 24 is a plan view of the same. As shown in FIGS. 18, 23, and
 24, in this case, the locking projection 756 of the disk-positioning
 member 751a is in the state in which the locking projection 756 enters the
 notch 734 formed on one side of the bar 731.
 In this condition, suppose that a user pushed the operating lever 732 that
 is a means for releasing the opening/closing-cover holding means downward
 on the papers showing FIGS. 18 and 24. The bar 731 is moved to some
 extent, and then the edge of the notch 734 of the bar 731 comes into
 contact with the locking projection 756 of the disk-positioning member
 751a.
 FIG. 25 is a plan view showing a state in which the edge of the notch 734
 of the bar 731 is in contact with the locking projection 756 of the
 disk-positioning member 751a and FIG. 26 is a partial perspective view of
 the same.
 The edge of the notch 734 is apt to cause the disk-positioning member 751a
 to pivot counterclockwise in FIG. 25 upon a supporting axis 613 as the
 pivot center by the pushing force of a user. However, the disk-positioning
 member 751a cannot pivot, since the disk-positioning member 751a is in
 contact with the fixed pin 614. As a result, the bar 731 cannot move any
 further, which does not result in an operation of the means for releasing
 the opening/closing-cover holding means.
 Thus, the possibility of the accidental operation of the means for
 releasing the opening/closing-cover holding means by a user when the case
 body is not inserted in the insertion portion 602 can be avoided.
 When the case body 101 is inserted in the insertion portion 602, as shown
 in FIG. 16, the contact portion 757 formed on one end face of the
 disk-positioning member 751a is in contact with a side face of the case
 body 101. The disk-positioning member 751a pivots clockwise as shown in
 FIG. 16 upon the supporting axis 613 as the pivot center. As a result, the
 locking projection 756 of the disk-positioning member 751a is released
 from the notch 734. Thus, the means for locking the means for releasing
 the opening/closing-cover holding means does not function. Therefore, a
 user can eject the disk cartridge by operating the operating lever 732 of
 the bar 731.
 Next, a disk-positioning means of the adapter according to the third
 embodiment of the present invention will be explain.
 The disk-positioning means of the present invention is used for adjusting
 the position of the disk in its thickness direction so that the disk 10
 can be surely inserted into the opening 102 of the case body when the case
 body 101 is inserted into the insertion portion 602 from the state in
 which the disk 10 is loaded in the insertion portion 602 of the adapter
 (FIG. 18). In view of the convenience in operation, it is preferred to
 provide the disk25 positioning means.
 As shown in FIGS. 13 and 14, the disk-positioning means of the present
 embodiment comprises disk-positioning members 751a and 751b, fixed pins
 614, 614, and torsion coil springs 760, 760. The disk-positioning members
 751a and 751b are maintained pivotably upon supporting axes 613, 613 as
 their pivot centers, respectively. The supporting axes 613 are formed at
 the both ends in the vicinity of the opening of the insertion portion 602
 of the lower case 601. Each of the disk-positioning members 751a and 751b
 has a first positioning portion 752 formed at its one end so as to hold
 the disk from the both sides. The fixed pins 614, 614 are fixed to the
 lower case 601 and come into contact with respective parts of the
 disk-positioning members 751a and 751b, thus controlling the pivot of the
 disk-positioning members 751a and 751b. The torsion coil springs 760, 760
 are retained by the spring hooks 755 of the members 751a, 751b and the
 lower case 602. The torsion coil springs 760, 760 press and fix the
 members 751a and 751b to the fixed pins 614, 614 by their elasticity. The
 disk-positioning means is provided at both ends in the vicinity of the
 opening of the insertion portion 602 respectively. However, with respect
 to the members having the same function, the both members are not
 differentiated from each other and are indicated with the same character
 in the explanation.
 The operation of the disk-positioning means with such a configuration will
 be explained.
 As shown in FIGS. 18, 23 and 24, when the opening/closing cover 201 and the
 disk 10 are loaded in the insertion portion 602 of the adapter, both the
 disk-positioning members 751a and 751b are pressed and fixed to the fixed
 pins 614 by the torsion coil springs 760, respectively. In this case, the
 first positioning portions 752 of the disk-positioning members 751a and
 751b hold the peripheral end of the disk 10 from its both sides to adjust
 the position of the disk in its thickness direction. Therefore, when the
 case body 101 is inserted into the insertion portion 602 from this state,
 the disk can be surely inserted into the opening 102 of the case body 101.
 After the peripheral end of the disk 10 is inserted into the opening 102 of
 the case body 101, when the case body 101 is further inserted into the
 insertion portion 602, the contact portions 757 formed on respective one
 end faces of the disk-positioning members 751a and 751b come into contact
 with the side faces of the case body 101. Then, as shown in FIG. 17, the
 disk positioning members 751a and 751b pivot clockwise and
 counterclockwise upon the supporting axes 613 as pivot centers
 respectively. As a result, the disk-positioning members 751a and 751b move
 away from the insertion portion 602.
 In the disk-positioning means having the above-mentioned configuration,
 when the disk is accommodated into the adapter and the adapter is then
 loaded into a drive unit, the accommodated disk is required to be in a
 rotatable condition. Therefore, consideration should be given to the
 surface swing and the deviation from the center during the rotation. When
 the disk 10 is held by the first positioning portions 752 described above,
 there is a possibility of disturbing the rotation of the disk. On the
 other hand, considering this, "play" in holding the disk 10 with the first
 positioning portions 752 is provided too much, the region subject to the
 positioning in the thickness direction of the disk 10 is increased.
 Consequently, it becomes difficult to insert the disk 10 into the opening
 102 of the case body stably.
 When the disk is accommodated in the adapter and the adapter is then loaded
 into the drive unit, it is preferable that the difference in position
 between the rotation center of the disk and the rotation axis of the drive
 unit is as small as possible.
 Therefore, when loading the adapter into the drive unit, it is preferred to
 adjust the position of the accommodated disk by a positioning means that
 adjusts the position more gently than by the first positioning portion.
 The adapter according to the present embodiment realizes this by second
 positioning portions 753 provided adjacent to the first positioning
 portions 752 of the disk-positioning members 751a and 751b.
 The function of the second positioning portions will be explained as
 follows.
 As shown in FIGS. 18, 23 and 24, the door 510 is closed with the disk 10
 being held by the first positioning portions 752. Positioning projections
 754 as contact members that come into contact with the door 510 are
 provided at the ends of the disk-positioning members 751a and 751b,
 respectively. The positioning projections 754 are formed so as to project
 toward the opening of the insertion portion 602. When the door 510 is
 closed, the contact faces 514 and 515 of the door 510 come into contact
 with the positioning projection 754 of the disk-positioning member 751a
 and with the positioning projection 754 of the disk-positioning member
 751b, respectively. Thus, as shown in FIG. 19, the disk-positioning
 members 751a and 751b pivot slightly clockwise and counterclockwise upon
 the supporting axes 613 as pivot centers, respectively. When the door 510
 is closed, the disk-positioning members 751a and 751b are elastically
 maintained by the elasticity of the torsion coil springs 760 with the
 positioning projections 754 being in contact with the contact faces 514
 and 515 of the door 510, respectively.
 FIG. 27 is a partial prospective view showing the state in which the door
 510 is closed and the second positioning portion 753 of the
 disk-positioning member 751a holds the disk 10, and FIG. 28 is a plan view
 of the same. When the door 510 is closed, the first positioning portions
 752 of the disk-positioning members 751a and 751b come apart from the disk
 10, resulting in the state in which the disk 10 is positioned between the
 adjacent second positioning portions 753.
 As is apparent from the comparison with FIGS. 23 and 24, the second
 positioning portions 753 hold the disk 10 with a larger gap in its
 thickness direction than that when the first positioning portions 752 do.
 Therefore, even if considering the surface swing and the deviation during
 the rotation of the disk that is loaded in a drive unit, there is no
 problem in rotating the disk. Moreover, since the position of the disk in
 the direction parallel to the disk surface is adjusted by the
 disk-positioning members 751a and 751b in addition to the opening/closing
 cover 201 including the disk holding members 202, the difference in
 position between the rotation center of the disk and the rotation axis of
 the drive unit when the disk is loaded into the drive unit can be
 maintained within a tolerance.
 In the present embodiment, a part of the disk-positioning member 751a
 forming the disk-positioning means is designed so as to be a part of the
 component of the means for locking the means for releasing the
 opening/closing-cover holding means at the same time. Thus, the
 configuration can be simplified and the number of parts can be reduced.
 However, the configuration is not limited to this. Needless to say, both
 the means may be formed with different components separately.
 In the adapter according to the third embodiment of the present invention,
 when the adapter is loaded into a drive unit, the shutter 503 is opened
 and a head of the drive unit passes the head access openings 502 and 603.
 Therefore, it is necessary that the adapter and the opening/closing cover
 loaded inside the adapter have shapes that secure a through area of the
 head respectively.
 FIG. 29 is a schematic perspective view showing the state in which the
 shutter 503 of the adapter 500 of the present embodiment accommodating the
 opening/closing cover 201 and the disk 10 is opened. FIG. 30 is a partial
 cross-sectional view taken on line III--III in the arrow direction of FIG.
 29.
 As shown in the figures, the adapter of the present embodiment has a
 bridging portion 615 within the head access openings 502 and 603. In order
 to allow the head to pass within the head access openings 502 and 603, the
 bridging portion 615 is formed so as to be thinner than the external
 surfaces of the upper case 501 and the lower case 601 and so as to be
 recessed from the both external surfaces. The thickness d11 of the
 bridging portion 615 that is recessed from both external surfaces is set
 so as to have the same thickness with the corresponding part of a disk
 cartridge having compatibility in external shape with the present adapter.
 The head of the drive unit is designed on the condition that the maximum
 thickness inside the head access openings 502 and 603 is d11. Therefore,
 it is preferable that both the thickness dl2 of the opening/closing cover
 holding plate 701 and the thickness dl3 of the opening/closing cover 201
 are the same as or thinner than the thickness d11 of the bridging portion
 615.
 Fourth Embodiment
 Next, a disk cartridge according to a fourth embodiment of the present
 invention will be explained.
 FIG. 31 is a perspective view showing the appearance of an example of a
 disk cartridge according to the fourth embodiment of the present
 invention. FIG. 32 is an exploded perspective view showing schematic
 shapes of the main components of the disk cartridge shown in FIG. 31. FIG.
 33 is a perspective view showing an opening/closing cover that is one of
 the components of the disk cartridge shown in FIG. 31. FIG. 34 is a
 schematic plan view showing a state during ejecting the disk accommodated
 in the disk cartridge shown in FIG. 31 after the opening/closing cover of
 the disk cartridge and a case body of the disk cartridge are separated.
 FIG. 35 is a schematic plan view showing a state in which the
 opening/closing cover and the case body of the disk cartridge shown in
 FIG. 31 are separated and the disk accommodated in the disk cartridge is
 ejected. FIG. 36 is an enlarged perspective view showing details of an
 example of a movable piece in the disk cartridge shown in FIG. 31, which
 is formed by integral formation with the upper half of the case body. FIG.
 37 shows partial cross-sectional perspective views illustrating an
 enlarged third locking means of the disk cartridge shown in FIG. 31. FIG.
 38 is an enlarged cross-sectional view of a grip portion of the disk
 cartridge shown in FIG. 31. The members having the same function as those
 in the first embodiment are indicated using the same characters. The
 duplicate explanations for those members are omitted here.
 The disk cartridge according to the present fourth embodiment is different
 from that according to the first embodiment in that a positioning portion
 (flange) is added. The positioning portion maintains a disk by positioning
 the disk between them in its thickness direction so that the disk does not
 come off an opening/closing cover. Further, the disk cartridge according
 to the present fourth embodiment is different from that according to the
 first embodiment in that a third locking means is provided with a movable
 piece that can correspond to a reversible third unlocking means of an
 adapter according to a fifth embodiment described later.
 As shown in FIGS. 31-35, a disk cartridge 1000 according to the fourth
 embodiment of the present invention comprises a case body 1110 and an
 opening/closing cover 1120 accommodated inside the case body 1110 in a
 withdrawable manner. The case body 1110 comprises an opening 1111, a
 disk-storage portion 1112, a movable piece 1503, a guide hole 1119, and a
 grip-guide part 1113. A disk 10 is inserted into or is ejected from the
 opening 1111. The disk-storage portion 1112 is formed continuously to the
 opening 1111 and forms a space where the disk 10 is accommodated. The
 movable piece 1503 is provided in the vicinity of the opening 1111 and can
 be elastically deformed in parallel with a disk surface. When third
 locking projections 209 provided at symmetrical positions with respect to
 the center line of the case body 1110 are removed by external force, the
 guide hole 1119 guides the removal operation. The grip-guide part 1113
 engages with a grip portion 1501 of the opening/closing cover 1120
 described later. The case body 1110 has a rectangular shape. The inside of
 the case body 1110 is formed of an upper case 1110a and a lower case 1110b
 that are formed in substantially the same shape. The movable piece 1503
 and the guide hole 1119 are formed substantially opposing each other in
 each of the upper case 1110a and the lower case 1110b.
 As shown in FIG. 36, the movable piece 1503 is formed by an integral
 formation with the case body 1110 via a bridge portion 1503a. The elastic
 deformation of the bridge portion 1503a can displace the movable piece
 1503 at least in an inplane direction parallel to the disk surface. The
 third locking projection 209 (not shown in FIG. 36) engages with a third
 locking hole 1511. A part of wall surfaces of the third locking hole 1511
 is formed of the movable piece 1503. The point of the movable piece 1503
 is formed in a hook shape so that the third locking projection 209 of the
 opening/closing cover is hooked and maintained by the movable piece 1503.
 When the movable piece 1503 is elastically moved to a predetermined
 position within a plane parallel to the disk surface in the direction
 shown by an arrow 1503b in the figure, a path (gap) leading to the outside
 of the case body 1110 in the direction shown by an arrow 209a from the
 third locking hole 1511 is formed. By passing the third locking projection
 209 through this path 209a, the opening/closing cover 202 fixed and held
 by the third locking means can be released reversibly. In an initial state
 of a disk cartridge, the third locking hole 1511 is engaged with the third
 locking projection 209 and is therefore closed.
 The opening/closing cover 1120 comprises a pair of disk holding members
 202, first locking projections 203, third locking projections 209, hooks
 1123, and a grip 1501. The hooks 1123 engage with an opening/closing-cover
 holding means of the adapter described later.
 One third locking projection 209 is provided at each side of the grip 1501
 of the opening/closing cover 1120. The two third locking projections 209
 do not have the same projections on the upper and lower surfaces of the
 opening/closing cover 1120. The two third locking projections 209 are
 formed so that when one of the projections 209 projects from one surface
 side, the other projection 209 projects from the other surface side. As
 shown in FIG. 37(a), when the third locking projection 209 fits into the
 third locking hole 1511, the other end surface of a lock key 208 is
 exposed within the guide hole 1119 formed opposing the locking hole 1511.
 The lock key 208 is designed so as to be cut away irreversibly by the
 application of a predetermined external force (for example, pressing by a
 pen point) through the guide hole 1119 in this state. Thus, the third
 locking means can be released irreversibly.
 A first groove 1124 is provided on the side face in the vicinity of the
 base of each disk holding members 202. First retaining portions 1242
 provided to position-in-height maintaining members 1240 of the adapter
 described later fit into the first grooves 1124, thus forming a
 position-in-height maintaining means. Further, a second groove 1125 is
 provided on the opening/closing cover 1120 on its side face that is
 exposed when the opening/closing cover 1120 is inserted in the case body
 1110. A second retaining portion 1216 of an operating member 1210a of the
 adapter described later fits into the second groove 1125, thus similarly
 forming the position-in-height maintaining means. The second groove 1125
 is formed in the vicinity of the center of the opening/closing cover 1120
 but is formed asymmetrically with respect to the center line of the
 opening/closing cover 1120 (for instance, asymmetrically in shape or
 formation position). Therefore, when the disk cartridge 1000 is inserted
 into the adapter described later to a predetermined position, the
 insertion is possible only with one orientation, and thus a side A of the
 disk cartridge can correspond to a side A of the adapter. The hooks 1123
 are formed in a left-right symmetric shape with respect to the insertion
 direction of the disk cartridge.
 As shown in FIG. 33, in the disk holding members 202, points 202b engage
 with the engagement portions 1117 of the case body 1110, thus adjusting
 the position of the disk holding members 202. Further, slopes formed in
 the width and thickness directions of the disk 10 are provided at the
 points 202b so as to allow the opening/closing cover 1120 to be inserted
 smoothly when the opening/closing cover 1120 is inserted into the case
 body 1110.
 First flanges 1126 are formed on the upper and lower faces of each end of
 the disk holding members 202 (in order to explain the points 202b, FIG. 33
 shows the state in which the upper first flange 1126 of the disk holding
 member 202 shown in the back is cut away). Each holding member 202 is
 formed so as to have a predetermined distance between the disk 10 and each
 of the upper and lower faces of the member 202 in the thickness direction
 of the disk 10 (the same distance as that of a disk-storage portion 1112
 forming a space where the disk 10 is accommodated). Therefore, the first
 flanges 1126 adjust the position in height of the disk 10 when the disk 10
 is accommodated in the adapter described later. Each first flange 1126 has
 a projection that projects in the disk direction. The projection adjusts
 the position of the disk in its thickness direction. Similarly, as shown
 in FIG. 38, both the upper and lower surfaces of the grip 1501 project in
 the disk 10 direction and form a second flange 1502 that adjusts the
 position of the disk 10 in its thickness direction. The first flanges 1126
 and the second flange 1502 can maintain the disk 10 when the
 opening/closing cover 1120 is drawn out from the case body 1110 so that
 the disk 10 does not come off the opening/closing cover 1120 and does not
 fall down. The first flanges 1126 are formed in a higher level than that
 of the basic thickness of the opening/closing cover 1120. When the
 opening/closing cover 1120 is accommodated in the case body 1110, the
 first flanges 1126 engage with cavities 1509 formed within the
 disk-storage portion 1112. Due to the grooves 1127, the first flanges 1126
 can be elastically deformed in the thickness direction. Therefore, when
 the opening/closing cover 1120 is drawn out from the case body 1110, the
 first flanges 1126 are elastically deformed in the thickness direction of
 the disk 10. Consequently, the first flanges 1126 escape from the cavities
 1509 formed inside the case body 1110, thus passing through the
 disk-storage portion 1112 and the opening 1111. Further, the upper and
 lower points of the first flanges 1126 are positioned at different
 positions from each other so as to enable the formation of the first
 flanges 1126 (see FIG. 35).
 On the other hand, the operation of withdrawing the opening/closing cover
 1120 from the case body 1110 is the same operation as in the disk
 cartridge according to the first embodiment. As shown in FIG. 34, the ends
 of the disk holding members 202 hold the accommodated disk 10 stably. As a
 result, the disk 10 can be withdrawn together with the opening/closing
 cover 1120 in the state as shown in FIG. 35. The grip 1501 in the vicinity
 of the center of the opening/closing cover 1120 is provided with the
 second flange 1502 projecting toward the disk direction. The second flange
 1502 adjusts the position of the disk 10 described above in its thickness
 direction. Therefore, the disk 10 does not fall off from the
 opening/closing cover 1120. Consequently, when grasping the disk 10 and
 drawing it out in the direction of the end of the opening/closing cover
 1120, the disk 10 can be removed from the opening/closing cover 1120 while
 the disk holding members 202 are elastically deformed outwards by the
 peripheral face of the disk 10.
 The grip 1501 is positioned at a higher level than that of the basic
 thickness of the opening/closing cover 1120. The shape formed at the
 higher level is designed so as not to be left-right symmetric with respect
 to the center line of the disk cartridge 1000. Similarly, the grip-guide
 part 1113 of the case body 1110 that engages with the grip 1501 also is
 not left-right symmetric with respect to the center line of the disk
 cartridge 1000. Thus, the disk cartridge 1000 is formed so that the
 opening/closing cover 1120 can be inserted into the case body 1110 only
 with one orientation. Therefore, when the opening/closing cover 1120 is
 inserted into the case body 1110 again after being withdrawn from the case
 body 1110, the opening/closing cover 1120 can be inserted only with the
 initial orientation. When the opening/closing cover 1120 is inserted into
 the case body 1110 again after the opening/closing cover 1120 and the disk
 10 are transferred into the adapter described later, the opening/closing
 cover 1120 can be inserted only with the initial orientation. Thus, a side
 A of the disk cartridge 1000 can correspond to a side A of the adapter,
 and a side B of the disk cartridge 1000 to a side B of the adapter.
 Needless to say, when the disk cartridge 1000 is loaded into the adapter,
 it is necessary to make the side A of the disk cartridge 1000 and the side
 A of the adapter correspond to each other and to form the disk cartridge
 1000 so as to be inserted into the adapter only with one orientation. This
 will be described later. The grip 1501 and the case body 1110 are engaged
 with each other, being positioned one upon another as shown in FIG. 38,
 thus avoiding the ingress of dirt and dust into the disk cartridge 1000.
 The case body 1110 comprises a head access opening 180, a shutter 181, an
 elastic spring 182, and a slider 1104. The slider 1104 is freely movable
 in the left-right direction by the guide of two guide portions 1507 and
 1508 formed in the case body 1110. The slider 1104 fixes the shutter 181
 and suspends one end of the elastic spring 182. The other end of the
 elastic spring 182 is suspended by the case body 1110. Thus, the elastic
 spring 182 provides force in the direction that the shutter 181 covers the
 head access opening 180. A shutter opening/closing hole 1506 formed in the
 slider engages with a shutter opening/closing lever that is provided in a
 drive unit and is not shown in the figure, thus opening and closing the
 shutter 181.
 The points 202b of the disk holding members 202 engage with the engagement
 portions 1117 of the case body 1110, and therefore the positions of the
 points 202b are regulated. Thus, it is avoided that the ends of the disk
 holding members 202 are inclined inwards and then come into contact with
 the disk 10.
 As shown in FIG. 33, the first locking projection 203 has a step 203b in
 the opposite side of a step 203a provided in the direction preventing the
 opening/closing cover 1120 and the case body 1110 from being separated by
 being engaged with the locking hole 105. The step 203b comes into contact
 with a step 1250a of an insertion-position-maintaining member 1250 of the
 adapter described later that is included in an insertion-position
 maintaining means when the disk cartridge is inserted into the adapter.
 A first unlocking claw 205 as shown in FIG. 33 is formed at a part of each
 hinge 204. The first unlocking claws 205 are pressed by first unlocking
 bars 1214 of operating members 1210a and 1210b of the adapter described
 later, thus displacing the hinges inwards.
 Fifth Embodiment
 Next, an adapter according to a fifth embodiment into which the disk
 cartridge of the fourth embodiment of the present invention can be
 inserted will be explained with reference to the drawings.
 FIG. 39 is an entire perspective view showing the appearance of an adapter
 according to the fifth embodiment of the present invention. FIG. 40 is a
 schematic plan view showing an internal structure of the adapter shown in
 FIG. 39 after removing an upper half and a shutter. FIG. 41 is an exploded
 schematic perspective view showing components of the adapter shown in FIG.
 39. The members having the same function as those in the third embodiment
 are indicated using the same characters, respectively. The duplicate
 explanations for those members are omitted here.
 An adapter 1200 of the present embodiment is formed by combining a
 rectangular upper case 1220 and a rectangular lower case 1230 so as to
 have a case-like form that can accommodate a disk cartridge. The adapter
 1200 comprises an insertion portion 602, a door 510, head access openings
 502 and 603, a shutter 503, and an elastic spring (not shown in the
 figures) for maintaining the shutter 503 in a closed state when the
 adapter 1200 is not loaded in a drive unit.
 As shown in FIG. 40, the operating members 1210a and 1210b are positioned
 at the back of the insertion portion 602 movably in a direction
 perpendicular to the insertion direction of the disk cartridge. A spring
 1212 provides force to one operating member 1210a in the left direction in
 the figure. A spring 1213 provides force to the other operating member
 1210b in the right direction in the figure. That is, the springs 1212 and
 1213 provide forces to the operating members 1210a and 1210b respectively
 so that the operating members 1210a and 1210b are separated from each
 other. The operating member 1210a extends crossing over the head access
 openings 502 and 603. On a side face of the operating member 1210a, a
 first unlocking bar 1214, a second convex part 1513, and a holding hook
 1215 are provided projecting from the side face. The first unlocking bar
 1214 can come into contact with the first unlocking claw 205 (see FIG. 33)
 formed at a part of the hinge 204 formed in the opening/closing cover
 1120. The second convex part 1513 engages with the second concave part
 1512 (see FIG. 36) formed in the movable piece 1503 of the case body 1110.
 The holding hook 1215 engages with the hook 1123 (see FIG. 33) formed in
 the opening/closing cover 1120. In the operating member 1210b, the same
 first unlocking bar 1214, second convex part 1513, and holding hook 1215
 are formed in the opposite shape respectively (in an asymmetrical shape
 with respect to the center line of the disk cartridge in its insertion
 direction). A pair of the first unlocking bars 1214 described above form a
 first unlocking means of the present invention. A pair of the second
 convex parts 1513 described above form a third unlocking means of the
 present invention. A pair of the holding hooks 1215 described above form a
 first opening/closing-cover holding means of the present invention.
 A second retaining portion 1216 that enters the second groove 1125 (see
 FIG. 33) formed in the opening/closing cover 1120 and holds the
 opening/closing cover 1120 in the thickness direction of a disk is formed
 in the vicinity of the center of the side face of the operating member
 1210a. A rack 1217 is formed at the right end of the operating member
 1210a. When a handle 1218 projecting on the upper face of the operating
 member 1210a is moved to the right through a window 1221 formed in the
 upper case 1220 by a finger, a gear (a pinion gear) 1203 that meshes with
 the rack 1217 rotates. Further, the operating member 1210b having a rack
 that meshes with the gear 1203 moves to the left. Consequently, the first
 unlocking bars 1214, the second convex parts 1513, and the holding hooks
 1215 that are provided at the right and left sides respectively move in
 the respective directions approaching each other at one time. That is to
 say, the first unlocking means, the third unlocking means, and the first
 opening/closing-cover holding means that are provided in each of the right
 and left sides of the disk cartridge with respect to the insertion
 direction can be operated at one time.
 Position-in-height maintaining members 1240 for maintaining the position in
 height of the opening/closing cover 1120 are arranged to the left and
 right of the insertion portion 602 movably in the direction perpendicular
 to the insertion direction of the disk cartridge as shown in FIGS. 40 and
 41. Springs 1241 provide forces to the position-in-height maintaining
 members 1240 inwards toward the insertion portion 602. In the
 position-in-height maintaining members 1240, first retaining portions 1242
 that enter the first grooves 1124 formed in the opening/closing cover 1120
 and hold the opening/closing cover 1120 are formed, respectively. The
 first retaining portions 1242 together with the above-mentioned second
 retaining portion 1216 form a position-in-height maintaining means
 included in the second opening/closing-cover holding means of the present
 invention.
 Insertion-position-maintaining members 1250 for holding the opening/closing
 cover at a predetermined position in the insertion direction are arranged
 to the left and right at the back of and outside the insertion portion 602
 as shown in FIGS. 40 and 41. The insertion-position-maintaining members
 1250 are provided on the upper and lower cases 1220 and 1230 pivotably
 upon axes 1251 as the pivot centers, respectively. Springs 1252 provide
 forces to the insertion-position-maintaining members 1250 in the direction
 toward the insertion portion 602. Step portions 1250a provided at the ends
 of the insertion-position-maintaining members 1250 engage with step
 portions 203b of first locking projections 203 formed in the
 opening/closing cover 1120 to hold the opening/closing cover 1120. Thus, a
 pair of the insertion-position-maintaining members 1250 form an
 insertion-position maintaining means included in the second
 opening/closing holding means of the present invention.
 Guide members 1270 are arranged to the left and right of the disk cartridge
 in the insertion direction in the vicinity of the entrance of the
 insertion portion 602. Each guide member 1270 is sandwiched between a
 groove 1234 formed in the lower case 1230 and a disk-positioning member
 1280. Therefore, the guide members 1270 can move only in the direction
 parallel to the insertion direction.
 Disk-positioning members 1280 for adjusting the position of the disk 10 in
 its thickness direction are arranged in both sides of the insertion
 portion 602 in the vicinity of its entrance pivotably upon axes 613 as the
 pivot centers, respectively. Torsion coil springs 760 urge the
 disk-positioning members 1280 toward the insertion portion 602. The
 disk-positioning members 1280 are in contact with the guide members 1270.
 As a result, the forces are provided to the guide members 1270 in the
 direction toward the entrance of the insertion portion 602 (downward on
 the paper showing FIG. 40) by the elasticity of the torsion coil springs
 760 via the disk-positioning members 1280, respectively. The guide members
 1270 to which forces are provided are maintained with stop faces 1271
 being pressed by the grooves 1234.
 A schematic loading method of the disk 10 into the adapter 1200 according
 to the fifth embodiment of the present invention will be explained using
 FIGS. 42-47 as follows.
 The door 510 is opened and then the disk cartridge 1000 is inserted into
 the insertion portion 602 with the opening 1111 of the case body 1110
 facing forward (FIG. 42).
 The disk cartridge 1000 is guided by the guide members 1270 and the
 insertion portion 602 and is inserted to the vicinity of the operating
 members 1210a and 1210b while pushing the disk-positioning members 1280,
 the position-in-height maintaining members 1240, and the
 insertion-position-maintaining members 1250 outwards. Then, the first
 unlocking claws 205 formed in the hinges 204 of the opening/closing cover
 1120 and the first unlocking bars 1214 formed in the operating members
 1210a and 1210b come into contact with each other. Consequently, the disk
 cartridge 1000 is in the state in which the disk cartridge 1000 is held
 gently inside the adapter. At the same time, the second convex parts 1513
 formed in the operating members 1210a and 1210b fit into the second
 concave parts 1512 formed in the movable pieces 1503 (FIGS. 48(a) and
 (b)). In this case, the disk cartridge 1000 can be drawn out easily when
 trying to draw out the disk cartridge 1000 with a greater force than the
 force with which the disk cartridge 1000 is held by the first unlocking
 bars 1214. Needless to say, the disk cartridge is kept in an initial state
 (in the state in which the disk is accommodated).
 Next, when the handle 1218 formed on the operating member 1210a is caught
 by a finger through the window 1221 of the upper case 1220 to be moved in
 the right-angled direction (in this case to the right) to the insertion
 direction of the disk cartridge 1000, the hinges 204 and the movable
 pieces 1503 are elastically deformed inwards. When the hinges 204 are
 elastically deformed inwards, each first locking projection 203 formed
 together with the respective hinge 204 as one component also is moved
 inwards, thus releasing the engagement between the first locking
 projections 203 and the locking holes 105 formed in the case body 1110
 (the operation of the first unlocking means). When the movable pieces 1503
 are elastically moved inwards, a part of the wall face of each third
 locking hole 1511 is moved, thus forming a path through which the third
 locking projection 209 can pass (the operation of the third unlocking
 means). At the same time, the holding hooks 1215 formed in the operating
 members 1210a and 1210b engage with the hooks 1123 formed in the
 opening/closing cover 1120 (the operation of the first
 opening/closing-cover holding means). Thus, the first locking means and
 the third locking means are unlocked and therefore the case body 1110 and
 the opening/closing cover 1120 can be separated. In addition, the
 opening/closing cover 1120 is retained by the operating members 1210a and
 1210b.
 While maintaining this state, the case body 1110 is drawn out from the
 adapter 1200, and the disk 10 and the opening/closing cover 1120 remain
 inside the adapter. By drawing out the case body 1110, the step portions
 1250a formed in the insertion-position-maintaining members 1250 engage
 with the step portions 203b of the first locking projections 203 formed in
 the opening/closing cover 1120, thus regulating the position of the
 opening/closing cover 1120 in its insertion direction (the operation of
 the insertion-position maintaining means included in the second
 opening/closing-cover holding means). When the insertion-position
 maintaining means is operated, the second retaining portion 1216 formed in
 the operating member 1210a enters the second groove 1125 formed in the
 opening/closing cover 1120, thus regulating the position of the
 opening/closing cover 1120 in the disk-thickness direction. Further, the
 first retaining portions 1242 formed in the position-in-height maintaining
 members 1240 enter the first grooves 1124 formed in the opening/closing
 cover 1120, thus regulating the position of the opening/closing cover 1120
 in the disk-thickness direction (the operation of the position-in-height
 maintaining means included in the second opening/closing-cover holding
 means). Thus, the opening/closing cover 1120 is held at a predetermined
 position. This condition is shown in FIG. 46.
 When the door 510 is closed (FIG. 47) and the disk cartridge is loaded into
 a drive unit designed for a disk cartridge having compatibility in
 external shape with the adapter 1200, information recorded on the disk 10
 inside the adapter can be reproduced or erased, or information can be
 recorded on the disk 10.
 The configuration and functions of the above will be explained in order as
 follows.
 The first unlocking means, the third unlocking means, and the first
 opening/closing-cover holding means of the present invention will be
 explained.
 In the first unlocking means, when the handle 1218 of the operating member
 1210a is pushed to the right through the window 1221 of the upper case
 1220 in the state in which the first unlocking claws 205 formed in the
 hinges 204 formed in the opening/closing cover 1120 are in contact with
 the first unlocking bars 1214 formed in the operating members 1210a and
 1210b, the first unlocking bars 1214 come to move toward the inside of the
 adapter 1200, thus deforming the hinges 204 inwards. As a result, the
 engagement between the first locking projections 203 and the locking holes
 105 is released.
 In the third unlocking means, when the handle 1218 of the operating member
 1210a is pushed to the right through the window 1221 of the upper case 220
 in the state in which the second convex parts 1513 formed in the operating
 members 1210a and 1210b fit into the second concave parts 1512 formed in
 the movable pieces 1503 formed in the case body 1110, the second convex
 parts 1513 are moved toward the inside of the adapter 1200, thus deforming
 the movable pieces 1503 inwards. Consequently, paths through which the
 third locking projections 209 can pass are formed.
 As a result, the lock between the first locking projections 203 and the
 locking holes 105 and the engagement between the movable pieces 1503 and
 the third locking projections 209 are released, thus allowing the
 opening/closing cover 1120 and the case body 1110 to be separated from
 each other.
 By pushing the handle 1218 of the operating member 1210a, the holding hooks
 1215 formed in the operating members 1210a and 1210b are moved inwards and
 therefore engage with the hooks 1123 formed in the opening/closing cover
 1120, thus retaining the opening/closing cover 1120.
 As described above, the operations of the first unlocking means, the third
 unlocking means and the first opening/closing-cover holding means allow
 the case body 1110 to be drawn out from the adapter 1200 while the
 opening/closing cover 1120 is left inside the adapter 1200. Needless to
 say, when the case body 1110 is drawn out from the adapter 1200 by
 operating the operating members 1210a and 1210b, the disk 10 is held by
 the opening/closing cover 1120. Consequently, the disk 10 also remains
 inside the adapter 1200.
 FIG. 44 is a view showing the state in which the first unlocking means, the
 third unlocking means, and the first opening/closing-cover holding means
 are operated by operating the operating members 1210a and 1210b. FIG. 44
 shows the state in which the hinges 204 are displaced and the hooks 1123
 of the opening/closing cover 1120 and the holding hooks 1215 of the
 operating members 1210a and 1210b engage with each other.
 FIG. 48 shows views illustrating the third unlocking means. The second
 convex parts 1513 formed in the operating members 1210a and 1210b fit into
 the second concave parts 1512 of the movable pieces 1503 formed in the
 case body 1110 (FIGS. 48(a) and (b)). The operating members 1210a and
 1210b are operated and the movable pieces 1503 are moved inwards (to the
 left on the paper showing FIG. 48(c)). Consequently, the paths through
 which the third locking projections 209 formed in the opening/closing
 cover 1120 can pass are formed, thus unlocking the third locking means
 (FIG. 48(c)).
 Next, the insertion-position maintaining means and the position-in height
 maintaining means that are the second opening/closing-cover holding means
 in the present invention will be explained.
 The insertion-position maintaining means aims to regulate the position of
 the opening/closing cover 1120 in its insertion direction after the case
 body 1110 is drawn out from the adapter 1200 so that the opening/closing
 cover 1120 is not drawn out from the adapter 1200. That is to say, when
 the disk cartridge 1000 is inserted into the adapter 1200, the
 insertion-position-maintaining members 1250 are rotated toward the outside
 of the insertion portion 602 by the side faces of the case body 1110.
 Then, while the disk 10 and the opening/closing cover 1120 are left inside
 the adapter 1200 by operating the operating member 1210a, the case body
 1110 is drawn out from the adapter. The insertion-position-maintaining
 members 1250 are rotated toward the inside of the insertion portion 602 by
 the forces provided by the springs 1252. The step portions 1250a of the
 insertion-position-maintaining members 1250 engage with the step portions
 203b of the first locking projections 203 formed in the opening/closing
 cover 1120. After that, even if the first opening/closing-cover holding
 means is released, the opening/closing cover 1120 cannot be drawn out from
 the adapter 1200. In addition, the first unlocking claws 205 formed in the
 above-mentioned opening/closing cover 1120 and the first unlocking bars
 1214 formed in the operating members 1210a and 1210b also regulate the
 position of the opening/closing cover 1120 in the direction of a plane
 parallel to the disk surface. Therefore, the position of the
 opening/closing cover 1120 is not changed unintentionally.
 The position-in-height maintaining means aims to adjust the position of the
 opening/closing cover 1120 in the disk-thickness direction. That is to
 say, when the disk cartridge 1000 is inserted into the adapter 1200, the
 position-in-height maintaining members 1240 are moved by the side faces of
 the case body 1110 toward the outside of the insertion portion 602. Then,
 after the first opening/closing-cover holding means is operated, the
 position-in-height maintaining members 1240 are moved toward the inside of
 the insertion portion 602 by the forces provided by the springs 1241 at
 substantially the same time that the opening/closing cover 1120 and the
 case body 1110 are separated. Then, the first retaining portions 1242
 formed in the position-in-height maintaining members 1240 enter the first
 grooves 1124 formed in the opening/closing cover 1120, thus regulating the
 position of the opening/closing cover 1120 in the disk-thickness
 direction. In addition, when the disk cartridge 1000 is inserted into the
 adapter 1200, the second retaining portion 1216 formed in the operating
 member 1210a enters the second groove 1125 formed in the opening/closing
 cover 1120, thus regulating the position of the opening/closing cover 1120
 in the disk thickness direction. Thus, by regulating the position in
 height of the opening/closing cover 1120 by the position-in-height
 maintaining means, the position of the disk 10 accommodated inside the
 adapter 1200 can be adjusted in its thickness direction by the first
 flanges 1126 and the second flange 1502 that are formed in the
 opening/closing cover 1120. Needless to say, considering the movement of
 the operating member 1210a, the second groove 1125 is formed so as to have
 a length corresponding to the movement. Furthermore, as mentioned above,
 since the second retaining portion 1216 and the second groove 1125 are
 designed so as to fit each other only in one orientation, the disk
 cartridge 1000 can be loaded into the adapter 1200 with the side A and the
 side B of the disk cartridge 1000 corresponding to the side A and the side
 B of the adapter 1200 respectively.
 Next, the disk-positioning means that holds the disk and adjusts its
 position will be explained. This function is the same as that of the
 disk-positioning means of the third embodiment. Therefore, mainly the
 different parts in the configuration will be explained. FIG. 49 is a
 perspective view of the disk-positioning member 1280 and FIG. 50 is a side
 view of the disk64 positioning member.
 The movable width of the disk 10, whose position is adjusted by the first
 flanges 1126 and the second flange 1502 of the opening/closing cover 1120,
 in its thickness direction is almost the same as that regulated by the
 inner wall of the disk cartridge 1000, which is sufficient for free
 rotation of the disk 10. Therefore, when trying to insert the disk 10 into
 the case body 1110 in such a condition, it is conceivable that the disk 10
 comes into contact with the case body 1110 and therefore the disk 10
 cannot be accommodated inside the case body 1110 securely. The
 disk-positioning means of the present embodiment is used for avoiding such
 a case.
 The disk-positioning means comprises disk-positioning members 1280 and
 torsion coil springs 760. As shown in FIGS. 41, 46 and 47, the
 disk-positioning members 1280 are maintained pivotably upon two supporting
 axes 613 formed at both ends of the insertion portion 602 in the vicinity
 of its opening as the pivot centers respectively. Each disk-positioning
 member 1280 has a first positioning portion 1285 formed at one end so as
 to hold the disk 10 from its both sides. The torsion coil springs 760 are
 retained by spring retaining faces 1286 of the disk-positioning members
 1280 and the lower case 1230, and provide forces to the disk20 positioning
 members 1280 toward the insertion portion 602 as shown in FIGS. 49 and 50.
 In each disk-positioning member 1280, a second positioning portion 1284
 for adjusting the position of the disk to such a degree that the disk can
 be rotated is further formed adjacent to the first positioning portion
 1285.
 The operation of the disk-positioning means having such a configuration
 will be explained. As shown in FIG. 46,when the opening/closing cover 1120
 and the disk 10 are loaded in the insertion portion 602, both the pairs of
 the disk-positioning members 1280 are in contact with the guide members
 1270. The positions of the guide members 1270 in a disk-cartridge
 insertion direction are regulated by the stop faces 1271 provided in the
 guide members 1270 and the grooves 1234 formed on the lower case 1230 (see
 FIG. 41). Therefore, the disk-positioning members 1280 stand still being
 pushed by the torsion coil springs 760 toward the insertion portion 602.
 In this case, the first positioning portions 1285 of the disk-positioning
 members 1280 hold the peripheral end of the disk 10 from its both sides,
 thus adjusting the position of the disk in its thickness direction.
 Consequently, when the case body 1110 is inserted into the insertion
 portion 602 in this condition, the disk 10 can be inserted into the
 opening 1111 of the case body 1110 without fail.
 After the peripheral end of the disk 10 is inserted into the opening 1111
 of the case body 1110, when the case body 1110 is inserted into the
 insertion portion 602, a contact surface 1287 that is one side face of the
 disk-positioning member 1280 comes into contact with a side face of the
 case body 1110. Then, as shown in FIG. 45, one disk-positioning member
 1280 pivots clockwise and the other disk-positioning member 1280
 counterclockwise upon the supporting axes 613 as the pivot centers,
 respectively. Thus, the disk-positioning members 1280 escape from the
 insertion portion 602.
 As shown in FIG. 46, when the door 510 is closed in the state in which the
 disk 10 is held by the first positioning portions 1285, one end of each
 guide member 1270 comes into contact with the door 510 in succession of
 the operation of closing the door 510. The guide members 1270 are pushed
 in a disk-cartridge insertion direction. Thus, the other end of each guide
 member 1270 presses the respective disk-positioning member 1280.
 Therefore, each disk-positioning member 1280 pivots slightly in a
 direction escaping from the insertion portion 602, i.e. one
 disk-positioning member 1280 pivots clockwise and the other positioning
 member 1280 counterclockwise, upon respective supporting axes 613 as the
 pivot centers respectively.
 FIG. 47 is a plan view showing the state in which the door 510 is closed
 and the second positioning portions 1284 of the disk-positioning members
 1280 hold the disk 10. When the door 510 is closed, the first positioning
 portions 1285 of the disk-positioning members 1280 come apart from the
 disk 10. Needless to say, the adjusting space of the disk by the second
 positioning portions 1284 of the disk-positioning members 1280 in such a
 condition is set to be larger than that by the first flanges 1126 and the
 second flange 1502 of the opening/closing cover 1120.
 Next, an outline of a method of ejecting the disk accommodated in the
 adapter according to the fifth embodiment of the present invention will be
 explained.
 The door 510 is opened (FIG. 46) from the condition shown in FIG. 47 and
 the case body 1110 is inserted into the insertion portion 602 (FIG. 45).
 At this time, the side faces of the case body 1110 come into contact with
 the disk-positioning members 1280 and the disk-positioning members 1280
 pivot toward the outside of the insertion portion 602 against the torsion
 coil springs 760. The disk 10 and the opening/closing cover 1120 are
 inserted into the disk-storage portion 1112 of the case body 1110
 sequentially. The case body 1110 is inserted into the insertion portion
 602 until the disk 10 and the opening/closing cover 1120 are accommodated
 in the disk-storage portion 1112 completely (FIG. 43). In this stage, the
 side faces of the case body 1110 and the position-in-height maintaining
 members 1240 come into contact with each other, and the position-in-height
 maintaining members 1240 are moved toward the outside of the insertion
 portion 602 against the springs 1241, thus releasing the
 position-in-height maintaining means. The side faces of the case body 1110
 and the insertion-position-maintaining members 1250 come into contact with
 each other, and the insertion-position-maintaining members 1250 are
 rotated toward the outside of the insertion portion 602 against the
 springs 252. Consequently, the insertion-position maintaining means of the
 disk cartridge is released. As described above, according to the present
 embodiment, the position-in-height maintaining means and the
 insertion-position maintaining means as the second opening/closing-cover
 holding means can be released sequentially merely by the insertion of the
 case body 1110 into the insertion portion 602. That is to say, in the
 present embodiment the means for unlocking the opening/closing cover
 holding means does not require a special member such as the bar 731
 releasing an opening/closing-cover holding means of the adapter 500 in the
 third embodiment and is formed of both components of the
 position-in-height maintaining means and the insertion-position
 maintaining means that are formed so as to be operated as described above.
 When the case body 1110 is further inserted, the steps 203b of the first
 locking projections 203 formed in both sides of the opening/closing cover
 1120 come into contact with the entrance edges of the opening 1111 of the
 case body 1110. Since slopes are formed at the entrance edges of the
 opening 1111, the first locking projections 203 are subjected to an inward
 force by the slopes, thus elastically deforming the hinges 204. As a
 result, when the hinges 204 are elastically deformed the first locking
 projections 203 slide on the inner walls 104 of the opening 1111.
 When the opening/closing cover 1120 is accommodated in the disk-storage
 portion 1112 completely, the first locking means and the third locking
 means of the disk cartridge 1000 function. That is to say, as explained
 with reference to FIGS. 31-35, when the first locking projections 203
 reach the locking holes 105, the hinges 204 are elastically restored.
 Then, the locking projections 203 fit into the locking holes 105 and thus
 the opening/closing cover 1120 is fixed and held to the case body 1110. At
 almost the same time, the slopes 1510 of the movable pieces 1503 of the
 case body and the third locking projections 209 of the opening/closing
 cover 1120 come into contact with each other. While the movable pieces
 1503 are elastically deformed inwards, the third locking projections 209
 pass through the paths 209a. When the third locking projections 209 have
 passed through the paths 209a completely, the movable pieces 1503 come
 back to the initial state. Consequently, the third locking projections 209
 are engaged with the third locking holes 1511.
 Thus, the opening/closing cover 1120 and the disk 10 can be ejected to the
 outside together with the case body 1110 as one body (FIG. 42).
 As described above, according to the present embodiment, by operating the
 operating member 1210a by hand, the first unlocking means, the third
 unlocking means, and the first opening/closing-cover holding means are
 operated at the same time, thus obtaining an adapter with a simple
 configuration.
 Further, the adapter is designed so that the hinges 204 formed in the
 opening/closing cover 1120 are not elastically deformed when the
 opening/closing cover 1120 is held inside the insertion portion 602 of the
 adapter. Therefore, creep that occurs by deforming the hinges 204 can be
 prevented.
 Similarly, when the opening/closing cover 1120 is held inside the insertion
 portion 602 of the adapter, a bridge portion 1503a connecting the movable
 portions 1503 and the case body 1110 is not elastically deformed.
 Therefore, creep deformation of the bridge portion 1503a does not occur
 even in the case where the opening/closing cover 1120 is inserted in the
 adapter for a long period.
 The releasing operation of the second opening/closing-cover holding means
 proceeds by simply inserting the case body 1110 into the insertion portion
 602. Thus, the operability in ejecting the disk is improved.
 The opening/closing cover 1120 that is installed inside the adapter can be
 held by the second opening/closing-cover holding means provided separately
 from the first opening/closing-cover holding means. Therefore, or example,
 even if a user manipulates the handle 1218 incorrectly when the door 510
 is opened (in the condition shown in FIG. 46), the opening/closing cover
 1120 and the disk 10 do not fall off from the insertion portion 602
 accidentally. Consequently, it is not necessary to provide the means for
 locking the means for releasing the opening/closing-cover holding means
 shown in the third embodiment, thus simplifying the configuration.
 EXAMPLES
 The present invention will be explained further in detail using an example.
 In the standard of DVD (digital video disc) RAM, there is a regulation
 about a cartridge accommodating a DVDRAM disk with a diameter of 120 mm.
 On the other hand, in order to improve the portability of the DVDRAM, the
 advent of a DVDRAM disk with a diameter of 80 mm and a disk cartridge
 accommodating the same has been waited and thus their standards have been
 studied.
 Then, in the present example, disk cartridges accommodating a DVDRAM disk
 with a diameter of 80 mm were produced experimentally according to the
 above-mentioned first, second, and fourth embodiments. On the other hand,
 adapters having compatibility with a cartridge in accordance with the
 standard of a DVDRAM accommodating the DVDRAM disk with a diameter of 120
 mm were produced experimentally according to the above-mentioned third and
 fifth embodiments. The DVDRAM disks with a diameter of 80 mm were loaded
 into the adapters, thus testing the recording, reproduction, and erasure
 of information in a drive unit designed for a DVDRAM.
 The disk cartridges and adapters produced experimentally will be described
 in detail as follows.
 Disk Cartridge 1
 A disk cartridge accommodating a DVDRAM disk with a diameter of 80 mm
 having the configuration described in the first embodiment was produced
 experimentally.
 A cartridge case had a width of 85 mm, a depth of 90 mm, and a thickness of
 5 mm. A head access opening 180 had a width of 23 mm.
 A case body 101 was formed in a predetermined shape using polycarbonate and
 an opening/closing cover 201 was formed in a predetermined shape using
 polyacetal. A shutter 181 was formed by processing a stainless steel plate
 with a thickness of 0.2 mm. A belt opener 183 was a cast of polyacetal.
 The obtained disk cartridge was loaded into a drive unit that had been
 produced experimentally and studied separately as a drive unit designed
 for a disk cartridge accommodating a DVDRAM disk with a diameter of 80 mm.
 Thus, it was confirmed that information could be recorded, reproduced, and
 erased.
 Disk Cartridge 2
 A disk cartridge accommodating a DVDRAM disk with a diameter of 80 mm
 having the configuration described in the second embodiment was produced
 experimentally.
 A cartridge case had a width of 85 mm, a depth of 90 mm, and a thickness of
 5 mm. A head access opening 180 had a width of 23 mm. A case body 101 was
 formed in a predetermined shape using polycarbonate and an opening/closing
 cover 201 was formed in a predetermined shape using polyacetal. A shutter
 181 was formed by processing a stainless steel plate with a thickness of
 0.2 mm. A belt opener 183 was a cast of polyacetal.
 The obtained disk cartridge was loaded into a drive unit that had been
 produced experimentally and studied separately as a drive unit designed
 for a disk cartridge accommodating a DVDRAM disk with a diameter of 80 mm.
 Thus, it was confirmed that information could be recorded, reproduced, and
 erased.
 Disk Cartridge 3
 A disk cartridge accommodating a DVDRAM disk with a diameter of 80 mm
 having the configuration described in the fourth embodiment was produced
 experimentally.
 A cartridge case had a width of 90 mm, a depth of 92 mm, and a thickness of
 5.2 mm. A head access opening 180 had a width of 26 mm.
 A case body 1110 was formed in a predetermined shape using polycarbonate
 and an opening/closing cover 1120 and a slider 1104 were formed in
 respective predetermined shapes using polyacetal. A shutter 181 was formed
 by processing a stainless steel plate with a thickness of 0.5 mm.
 The obtained disk cartridge was loaded into a drive unit that had been
 produced experimentally and studied separately as a drive unit designed
 for a disk cartridge accommodating a DVDRAM disk with a diameter of 80 mm.
 Thus, it was confirmed that information could be recorded, reproduced, and
 erased.
 Adapter 1
 An adapter having the configuration described in the third embodiment and
 the compatibility with the cartridge in accordance with the standard of
 the DVDRAM accommodating a DVDRAM disk with a diameter of 120 mm was
 produced experimentally.
 An adapter case had a width of 124.6 mm, a depth of 135.5 mm, and a
 thickness of 8 mm. In upper and lower cases, a head access opening was
 provided for inserting a disk motor and an optical head as shown in FIGS.
 12 and 13. The head access opening was covered by a shutter that was
 opened and closed to the left and right. The head access opening for a
 disk motor had a width of 34 mm and one for an optical head had a width of
 39 mm.
 An upper case 501, a lower case 601, and a door 510 were formed in
 respective predetermined shapes using polycarbonate. A press-rotating
 member 711 and disk-positioning members 751a, 751b were formed in
 respective predetermined shapes using polyacetal. An opening/closing cover
 holding plate 701 and a bar 731 releasing an opening/closing-cover holding
 means were obtained by processing stainless steel plates in respective
 predetermined shapes.
 Adapter 2
 An adapter having the configuration described in the fifth embodiment and
 the compatibility with the cartridge in accordance with the standard of a
 DVDRAM accommodating the DVDRAM disk with a diameter of 120 mm was
 produced experimentally.
 An adapter case had a width of 124.6 mm, a depth of 135.5 mm, and a
 thickness of 8 mm. In upper and lower cases, a head access opening was
 provided for inserting a disk motor and an optical head as shown in FIGS.
 39 and 40. The head access opening was covered by a shutter that was
 opened and closed to the left and right. The head access opening for a
 disk motor had a width of 34 mm and one for an optical head had a width of
 39 mm.
 An upper case 1220, a lower case 1230, and a door 510 were formed in
 respective predetermined shapes using polycarbonate. Operating members
 1210, position-in-height maintaining members 1240,
 insertion-position-maintaining members 1250, and disk-positioning members
 1280 were formed in respective predetermined shapes using polyacetal.
 Effect
 By inserting each of the above-mentioned disk cartridges 1 and 2 into the
 insertion portion 602 of the obtained adapter 1 in order, the disk and the
 opening/closing cover were loaded into the adapter. Then, the adapter was
 loaded into a drive unit designed for a cartridge in accordance with the
 DVDRAM standard. As a result, it was confirmed that information could be
 recorded, reproduced, and erased without any problem in both cases. After
 that, the case body was inserted into the insertion portion 602 of the
 adapter and then the accommodated disk and the opening/closing cover were
 ejected. There was no particular problem in operability in loading or
 ejecting the disk and the opening/closing cover from the adapter via the
 case body. Further, the disk cartridge 3 was inserted into the insertion
 portion 602 of the obtained adapter 2 and the same test as in the adapter
 1 was carried out to confirm the same effect.
 Second Invention
 Embodiments of the present second invention will be explained in detail
 with reference to the drawings.
 Sixth Embodiment
 FIG. 52 is a perspective structural view showing a disk cartridge according
 to an embodiment of the present invention. FIG. 53 is a perspective
 structural view showing the state in which a shutter of the disk cartridge
 is opened. A substantially rectangular case body 2003 formed of an upper
 half 2001 and a lower half 2002 comprises a disk-storage portion that
 accommodates a disk 2004 in its inside. An opening 2005 is provided in the
 upper and lower halves, and a disk motor and an optical pickup can be
 inserted through the opening 2005. Normally, a shutter 2006 covers the
 opening 2005 through which the optical pickup and the disk motor of a
 drive unit intrude so that the disk 2004 can not be touched easily.
 A bridge portion 2023 is formed in the front-end side of the opening 2005.
 The bridge portion 2023 is thinner than the case body 2003. That is to
 say, the bridge portion 2023 is formed so as to be recessed from the upper
 and lower surfaces of the case body 2003.
 A U-shaped shutter 2006 for covering and uncovering the opening 2005 is
 slidably provided on the case body 2003. When a disk cartridge is inserted
 into a drive unit, the shutter 2006 is moved. The shutter 2006 comprises
 two opposed shielding plates 2007 and a connecting portion 2008
 interconnecting the two shielding plates 2007. An engagement portion 2010
 is formed in the connecting portion 2008. The engagement portion 2010 can
 be engaged with a shutter opener (not shown in the figure) provided in a
 loading mechanism (not shown in the figure) of the drive unit when the
 disk cartridge is loaded into the drive unit. The engagement portion 2010
 has a configuration in which the engagement portion 2010 crosses the
 connecting portion 2008 and connects the two shielding plates 2007 to each
 other so as to be seen from the two faces of the case body 2003. The
 connecting portion 2008 fixes and holds the thin and long slider 2009
 while covering the slider 2009. The slider 2009 can be moved along the
 front end of the case body 2003. The surface of the slider 2009 is in the
 same level as or is recessed from the leading end face of the bridge
 portion 2023 of the case body 2003.
 A torsion coil spring 2014 is provided in the left side of the front end of
 the case body 2003. The torsion coil spring 2014 urges the shutter 2006 in
 the direction in which the shutter 2006 covers the opening 2005. The face
 of the front end (a guide portion 2026) of the case body 2003 on the side
 to which the shutter 2006 is not moved is at substantially the same level
 as or protrudes from the surface of the connecting portion 2008 of the
 shutter 2006.
 The configurations and operations of retaining portions 2022 provided at
 the rear end of the case body 2003 and an opening/closing cover 2020 for
 ejecting a disk will be described later with reference to other drawings.
 A shutter opening/closing function of a disk cartridge according to the
 present embodiment
 A shutter opening/closing function of the disk cartridge according to the
 present embodiment will be described with reference to the drawings.
 FIGS. 54(a)-(d) show plan views illustrating a shutter opening/closing
 operation by shutter openers of a disk cartridge in a drive unit (not
 shown in the figure). FIG. 54(a) shows the state before the disk cartridge
 comes into contact with the shutter openers, and FIG. 54 (b) shows the
 state at the moment when the both come into contact with each other. FIG.
 54(c) shows a state during opening of the shutter by the openers engaged
 with the shutter. FIG. 54(d) shows the state in which the shutter has been
 opened completely. A shutter opener P2 that is not engaged comes into
 contact with a guide portion 2026 provided at the front end of the case
 body 2003 to be guided.
 Its operation will be described with reference to FIG. 54 as follows.
 Two rollers R1 and R2 provided at the ends of the shutter openers P1 and P2
 are arranged substantially in parallel to the leading face of the
 cartridge before coming into contact with the disk cartridge. Upon the
 contact, the roller R1 engages with an engagement portion 2010 on the
 shutter 2006. Since the disk cartridge is moved forward by a loading
 mechanism (not shown in the figure), the shutter openers pivot
 accordingly. The engagement portion 2010 of the shutter 2006 has engaged
 with the roller R1 and therefore the shutter 2006 slides to the left to be
 opened. The other roller R2 comes into contact with the leading face of
 the disk cartridge. However, since no engagement portion for the roller R2
 is provided, it moves on the guide portion 2026 of the front end of the
 disk cartridge without being retained. Thus, the two rollers R1 and R2 are
 moved outwards in the direction shown by an arrow, i.e. a direction in
 which the rollers R1 and R2 are spaced from each other after the
 engagement of the roller R1.
 In this case, the rollers R1 and R2 of the shutter openers P1 and P2 do not
 overlap in the region where they are moved at the front end of the disk
 cartridge. Therefore, it is not necessary that the case body 2003, i.e.
 the disk cartridge has a thickness set considering an anticipated overlap.
 Consequently, the thickness of the case body can be set considering only
 the width of one roller and thus the thickness can be decreased by
 arranging the engagement portion 2010 and the guide portion 2026 so that
 the guide portion 2026 does not overlap in the region where the engagement
 portion 2010 is moved.
 As shown in FIG. 54(d), when the shutter 2006 is opened completely, the
 opening 2005 is uncovered to the front end of the case body 2003. The
 engagement portion 2010 to be engaged with the shutter opener is arranged
 movably along the front end of the case body including the bridge portion
 2023. When the shutter 2006 is opened completely, the center at the front
 end of the case body 2003 has only the bridge portion 2023 recessed from
 the two case faces. Therefore, an optical head of a drive unit and a cramp
 mechanism for a disk need to cross over merely the bridge portion 2023
 when being passed. Thus, by decreasing the thickness of the bridge portion
 2023, the thickness of the drive unit itself can be decreased at the same
 time.
 Further, as shown in FIG. 55, which is a perspective structural view of the
 front end of the cartridge, a notch 2027 is provided at the end of the
 connecting portion 2008 of the shutter 2006 and in the guide portion 2026
 side, and an engagement portion (a convex part in the present embodiment)
 2028 that can fit into the notch 2027 is formed in the guide portion 2026
 and in the connecting portion 2008 side. In addition, the surface of the
 guide portion 2026 including this convex part 2028 is formed so as to be
 at substantially the same level as or protrude from the face of the
 connecting portion 2008. The roller R2 of the shutter opener P2 is formed
 so as to come into contact only with the guide portion 2026 including the
 convex part 2028 and not with the connecting portion 2008. By such a
 configuration, the surfaces (the convex part 2028 and the guide portion
 2026) on which the roller R2 is guided have no difference in level and
 therefore the shutter opener can move on the guide portion 2026 smoothly.
 The shutter opener does not get stuck on the connecting portion 2008
 during the movement. Therefore, the load resistance does not increase,
 thus obtaining an excellent operational feeling. In this case, the guide
 portion 2026 is not formed at the center portion of the leading end face
 and the convex part 2028 is formed in the connecting portion 2008 side of
 the guide portion 2026 intentionally. This is because when the guide face
 2026 is formed at the center portion of the leading end face, it is
 necessary to shorten the length of the connecting portion 2008 in the
 moving direction in order to allow the shutter 2006 to be opened and
 closed by the shutter openers while permitting reverse-use, which causes
 the decrease in the strength of the connecting portion.
 A function for preventing erroneous insertion of a disk cartridge according
 to the present embodiment
 A function for preventing erroneous insertion of the disk cartridge
 according to the present embodiment will be explained with reference to
 the drawings.
 FIGS. 56(a)-(c) are plan views showing the operation of the disk cartridge
 and the shutter openers when the disk cartridge is inserted into a drive
 unit (not shown in the figures) with its front side back. FIG. 56(a) shows
 a state before the shutter openers come into contact with the cartridge.
 FIG. 56(b) shows a state at the moment when the both come into contact
 with each other. FIG. 56(c) shows a state in which the shutter openers are
 engaged with retaining portions.
 In FIG. 56, numerals 2021 and 2022 indicate a second guide portion provided
 at the rear end of the case body and retaining portions arranged at the
 rear end, respectively. At the rear end of the case body 2003, the
 retaining portions 2022 are formed symmetrically with respect to the
 center line of the case body 2003. The retaining portions 2022 are formed
 of a hook-shaped cut when seen from the case-face side, The second guide
 portion 2021 and the retaining portions 2022 are provided in a region
 where the shutter opener moves.
 Its operation will be described with reference to FIG. 56 as follows.
 When the cartridge is inserted with its front side back, the ends of the
 shutter openers P1 and P2 come into contact with and are guided by the
 second guide portion 2021 of the rear end of the case body. The shutter
 openers P1 and P2 fit into the two retaining portions 2022 at
 substantially the same time. However, the retaining portions 2022 are
 different from the engagement portion 2010 provided in the slidable
 shutter 2006 as described above in that the shutter openers P1 and P2
 cannot pivot when both the rollers R1 and R2 of the shutter openers P1 and
 P2 engage with the fixed retaining portions 2022, thus regulating the
 insertion of the disk cartridge. Furthermore, since a pair of the
 retaining portions 2022 are arranged symmetrically with respect to the
 center line of the case body, erroneous insertion of the cartridge can be
 regulated by the shutter openers P1 and P2 regardless of the side of the
 cartridge. In addition, it can be avoided that the load at the time of the
 regulation is biased to one of the two shutter openers P1 and P2.
 A chucking function of the disk cartridge of the present embodiment
 A chucking function of the disk cartridge of the present embodiment will be
 explained with reference to the drawings as follows.
 As shown in FIG. 52, 53, 56 or 57, the retaining portions 2022 have a
 hook-like shape. FIGS. 57(a) and (b) are plan views showing an engagement
 operation between a disk-cartridge chucking mechanism and the disk
 cartridge, for example, within a changer unit (not shown in the figures).
 For instance, when the disk cartridge is adapted to a changer unit or the
 like, during the operation of changing disk cartridges pins provided at
 the ends of chucking arms C as a chucking mechanism engage with hook
 shaped portions 2024 of retaining portions provided at the rear end of the
 case body 2003 as shown in FIG. 57, thus enabling the operation of
 changing the disk cartridges. Therefore, the formation of the retaining
 portion for preventing the above-mentioned reverse insertion at least
 partially in a hook shape enables this chucking operation. As a result, it
 is not necessary to form grooves or the like in other parts of the case
 body as in a conventional technique. Therefore, it is enough for a
 disk-storage portion for accommodating the disk to have a size that is
 required and sufficient for driving the disk. Thus, it is not necessary to
 form the disk-storage portion with a larger size than that required.
 A disk ejecting function of the disk cartridge of the present embodiment
 A disk ejecting function of the disk cartridge of the present embodiment
 will be explained with reference to the drawings as follows.
 FIG. 58 is a perspective structural view showing a state of inserting or
 ejecting the disk 2004 in which the opening/closing cover 2020 for
 ejecting a disk pivots upon a pivot axis provided at the rear end of the
 case body 2003. FIG. 58 shows a configuration in which the opening/closing
 cover 2020 is opened by pivoting upon the pivot axis, which allows the
 opening/closing cover 2020 to be positioned easily when the cover is
 closed and avoids that a user loses the opening/closing cover 2020.
 However, another configuration in which the opening/closing cover can be
 separated from the case body completely when being opened may be employed.
 It is not always necessary to arrange the opening/closing cover 2020 for
 ejecting a disk only at the rear end of the case body 2003. For example,
 the opening/closing cover 2020 may be provided at either side end of the
 case body, particularly at the side end shown in the right side in FIG. 1.
 FIG. 59 is a perspective structural view of a disk cartridge of another
 embodiment having such a configuration. As shown in FIG. 59, when an
 opening/closing cover 2200 for ejecting a disk is provided at a side end,
 the disk cartridge may be designed so that the opening/closing cover 2200
 does not obstruct the auto-loading, for example, so that the
 opening/closing cover 2200 is located at a position slightly inward from
 the side end face of the case body 2300 to be fixed provisionally when
 being closed, since it is conceivable that the case body are guided by its
 side ends at the time of auto-loading of the disk cartridge into a
 recording and reproducing unit. As shown in FIG. 59, the opening/closing
 cover is arranged at the side end in the right side in FIG. 52. This is
 because a moving portion of the torsion coil spring 2014 playing a part in
 opening and closing the shutter is provided in the vicinity of the left
 side end. Therefore, the opening/closing cover may be arranged at the left
 side end when, for example, the torsion coil spring 2014 is provided in
 the vicinity of the right side end that is the opposite side end to that
 shown in the drawing while the shutter 2006 is opened and closed in the
 same direction as in FIG. 52.
 By providing the opening/closing cover in such a manner, a disk can be
 ejected from the disk-storage portion while the characteristics of each
 function described above are maintained.
 In the above-mentioned embodiment, a disc-shaped recording and reproducing
 medium is explained as an optical disk in which information is recorded
 and reproduced by irradiation of light. However, needless to say, the
 medium is not always limited to this. As long as information can be
 recorded on and reproduced from both sides of the medium, any media for
 optical recording, magneto-optical recording, magnetic recording or other
 recording methods may be employed. In addition, the present embodiment
 also can be applied to a disk on which information has been recorded and
 which is only capable of reproducing the information and not capable of
 rerecording, rewriting, or overwriting, such as a so-called CD (a compact
 disc). Further, as the disk recording and reproducing unit described
 above, any disk reproducing units only capable of reproduction or any disk
 recording units only capable of recording can be used, as long as a disk
 cartridge having such a configuration as described above in the embodiment
 can be loaded.
 In the above-mentioned embodiment, not only the recording and reproducing
 surface of a disk but also the center hole of the disk for rotational
 drive of the disk is exposed from the opening and is covered by the
 shutter. However, the same effect can be obtained even when a
 configuration of such a disk cartridge of another embodiment shown in FIG.
 60 is employed. In the configuration, the center hole of a disk is always
 exposed from a second opening 2307 provided at the center portion of a
 case body 2301, only a recording and reproducing surface of the disk is
 exposed from a first opening 2305, and only the first opening 2305 is
 covered by a shutter 2306.
 Moreover, in all the above-mentioned embodiments, for example, as shown in
 FIG. 52, the explained disk cartridge is provided with all of the shutter
 opening/closing operation function, the erroneous insertion preventing
 function, the chucking function, and the disk ejecting function. However,
 the disk cartridge is not always limited to this. Needless to say, the
 present invention also can be applied to disk cartridges such as those
 having the shutter opening/closing operation function and the disk
 ejecting function, those having the erroneous insertion preventing
 function, the chucking function, and the disk ejecting function, those
 having only the erroneous insertion preventing function and the disk
 ejecting function, those having the shutter opening/closing operation
 function, the erroneous insertion preventing function, and the chucking
 function, those having only the shutter opening/closing operation function
 and the erroneous insertion preventing function, those having only the
 shutter opening/closing operation function, and those having only the
 erroneous insertion preventing function.
 As described above, according to the present second invention, the shutter
 can be opened and closed smoothly without decreasing the size of the
 disk-storage portion for accommodating a disk. Furthermore, the present
 second invention can handle with the erroneous insertion of the disk
 cartridge with its front side back and at the same time enables a disk
 change operation in a changer unit or the like and an accommodated disk
 itself to be ejected. Thus, the present invention provides an effect that
 a disk cartridge can be decreased in size and thickness and at the same
 time a drive unit also can be decrease in its size and thickness while
 having functions required for a disk cartridge.
 Third Invention
 Embodiments of the present third invention will be explained in detail with
 reference to the drawings as follows.
 Seventh Embodiment
 FIG. 64 shows front views of a disk cartridge of the seventh embodiment of
 the present invention. FIG. 64(A) shows the same when a shutter is closed
 and FIG. 64(B) shows the same when the shutter is opened. A shutter 3002
 is illustrated with hatching so that the position of the shutter is
 recognized easily.
 In FIG. 64, a numeral 3001 indicates a cartridge body made of synthetic
 resins in which a disk 3003 of a recording medium is accommodated
 rotatably. A numeral 3001a indicates an opening provided in both faces of
 the cartridge body 3001 for exposing surfaces of the disk 3003 so that
 light can be irradiated onto the disk 3003 across its inner and outer
 peripheries for recording and reproducing information. In the cartridge
 body 3001 shown in FIG. 64, it is necessary to hold a center hole of the
 disk 3003 so that the disk 3003 is rotated by a disk recording and
 reproducing unit. Therefore, the opening 3001a is provided so as to expose
 the center hole of the disk 3003 completely. A numeral 3002 indicates a
 shutter formed of a thin plate made of metal such as aluminum or the like
 or a synthetic resin plate. The shutter 3002 is slidably maintained by the
 cartridge body 3001 so as to shield the disk 3003 by covering the opening
 3001a completely and expose the disk 3003 by uncovering the opening 3001a.
 The disk cartridge of the present embodiment is different from the
 conventional disk cartridge shown in FIGS. 68 and 69 in that the cartridge
 body of the present embodiment has a width narrower than that of the
 cartridge body shown in FIG. 69 and has a size that is sufficient and
 minimum for accommodating the single disk 3003, while the opening 3001a of
 the disk cartridge of the seventh embodiment has substantially the same
 width in the sliding direction as that of the opening 3101a shown in FIG.
 68, and the disk 3003 has the same diameter as that of a disk 3003 with a
 small diameter shown in FIG. 69.
 Its operation will be explained with reference to FIG. 64 as follows.
 As shown in FIG. 64(A), the shutter 3002 of the present embodiment has
 substantially the same width in its sliding direction as that of a shutter
 3102 of a disk cartridge for a disk with a larger diameter shown in FIG.
 68 and can be opened in one direction by an opener lever OL of a disk
 recording and reproducing unit. A shutter return spring 3004 is provided
 inside the cartridge and plays a roll for providing a returning force to
 the shutter 3002. As shown in FIG. 64(B), the opener lever OL of the disk
 recording and reproducing unit engages with a concave part 3002a of the
 shutter and then the shutter 3002 slides, thus exposing the disk 3003
 through the opening 3001a. In this case, by positioning a part of the
 shutter 3002 outside the cartridge body 3001, a space where the shutter
 3002 is positioned after being moved can be made small. Therefore, the
 disk cartridge itself has a size that is sufficient and required for
 accommodating the disk 3003 inside, thus preventing the disk cartridge
 from having such a large size as that of a conventional disk cartridge for
 a small-diameter disk. That is to say, in the disk cartridge of the
 present embodiment, the relationship, L0.gtoreq.L2 holds between L0
 representing a width of the opening and L2 representing a width of a
 region where the shutter is positioned after being moved to the side (see
 FIG. 70). In addition, in the present embodiment, one shutter 3002 covers
 the opening 3001a completely. Therefore, the shutter width L1 should
 satisfy L1.gtoreq.L0, thus satisfying the relationship,
 L1.gtoreq.L0.gtoreq.L2.
 Eighth Embodiment
 FIGS. 65 and 66 are front views of a disk cartridge of the eighth
 embodiment according to the present invention. In each figure, (A) shows
 the same when a shutter is closed and (B) shows the same when the shutter
 is opened. The shutter is illustrated with hatching so that the position
 of the shutter is recognized easily as in FIG. 64.
 In FIGS. 65 and 66, numerals 3012 and 3015 indicate an upper shutter and a
 lower shutter, respectively. Each shutter is formed of a thin plate made
 of metal such as aluminum or the like or a synthetic resin plate. The
 shutters are slidably maintained by a cartridge body 3011 so as to shield
 a disk 3003 by being positioned adjacent to each other to cover an opening
 3001a completely as shown in FIGS. 65(A) and 66(A) or so as to expose the
 disk 3003 by moving to the side from the opening 3011a with both the
 shutters being placed one upon another to uncover the opening 3011a as
 shown in FIGS. 65(B) and 66(B). Other constructive elements are the same
 in the seventh embodiment shown in FIG. 64.
 The disk cartridge of the present embodiment is different from that of the
 seventh embodiment shown in FIG. 64 as follows. In the seventh embodiment,
 the shutter is formed of one shutter 3002 and a part of the shutter 3002
 is positioned outside the cartridge body 3001 beyond its outer periphery
 when the shutter is opened. However, in the present embodiment, the
 shutter is formed of two shutter members 3012 and 3015 and they are not
 positioned outside the cartridge body 311 when being opened, which is
 attained by sliding them in the same direction, positioning them one upon
 another so that the upper shutter 3012 covers the lower shutter 3015, and
 placing them between a front end of the opening 3011a in the sliding
 direction and an outer peripheral end of the cartridge body 3011 that is
 nearer to the above-mentioned front end (a region where the shutter is
 positioned after being moved).
 The engagement position where the opener and the shutter are engaged with
 each other is provided to the lower shutter 3015 of the two shutter
 members in FIG. 65 and to the upper shutter 3012 in FIG. 66. When the
 engagement position is provided to the lower shutter 3015 (FIG. 65), the
 upper shutter 3012 requires an accelerating mechanism so as to move more
 quickly than the lower shutter 3015 with respect to the movement of the
 opener. However, when the engagement position is provided to the upper
 shutter 3012 (FIG. 66), the shutters can be operated when the shutters are
 designed so that the engagement can be maintained even when the upper
 shutter 3012 is positioned over the lower shutter 3015.
 Thus, effects not only that a disk can be accommodated without increasing
 the width of the cartridge body in the sliding direction, but also that
 the shutters are not positioned outside the cartridge beyond its outer
 periphery even when the shutters are opened and the opening is exposed can
 be obtained.
 In FIGS. 65 and 66 showing the present embodiment, the upper shutter 3012
 and the lower shutter 3015 are positioned to the left (at a position
 further to the position where the upper and lower shutters are located one
 upon another when being opened) and to the right (at a position nearer to
 the position where the upper and lower shutters are located one upon
 another when being opened) respectively in the state in which the opening
 3011a is covered. However, the positions of the upper and lower shutters
 are not always limited to this. The upper and lower shutters may be
 positioned oppositely.
 The shutter was formed of two shutter members. However, needless to say,
 the same effect can be obtained even when three or more shutter members
 are used.
 Furthermore, FIGS. 65(A) and 66(A) show the configuration in which an end
 of the upper shutter 3012 and an end of the lower shutter 3015 are in
 contact with each other when the shutter is closed. However, the upper
 shutter 3012 and the lower shutter 3015 may overlap slightly each other
 (for example, about 1 mm). Especially, by providing a L-shaped bend (a
 hook) at respective overlapping parts, as in FIGS. 65(C) and 66(C) showing
 enlarged cross-sectional views of the shutter on the plane perpendicular
 to a disk surface and parallel to its sliding direction, the movement of
 the shutters can be controlled and ingress of dust or the like from the
 outside can be avoided.
 Ninth Embodiment
 FIG. 67 shows front views of a disk cartridge of a ninth embodiment
 according to the present invention. FIG. 67(A) shows the same when a
 shutter is closed and FIG. 67(B) shows the same when the shutter is
 opened. Similarly, the shutter is illustrated with hatching.
 In FIG. 67, numerals 3022 and 3025 indicate a left shutter (a first shutter
 member) and a right shutter (a second shutter member), respectively. Each
 shutter is formed of a thin plate made of metal such as aluminum or the
 like or a synthetic resin plate. The left and right shutters are slidably
 maintained by a cartridge body 3021 so as to shield a disk 3003 by being
 positioned adjacent to each other to cover an opening 3021a completely as
 shown in FIG. 67(A) or so as to expose the disk 3003 by being moved from
 the opening 3021a to the side to uncover the opening 3021a as shown in
 FIG. 67(B). Other elements are the same as in the seventh and eighth
 embodiments shown in FIGS. 64, 65, and 66.
 The disk cartridge of the present embodiment is different from that of the
 eighth embodiment shown in FIGS. 65 and 66 as follows. In the eighth
 embodiment, the shutter is formed of two upper and lower shutters 3012 and
 3015 that are positioned one upon another when being opened. However, in
 the present embodiments the shutter is formed of the two left and right
 shutters 3022 and 3025 and they slide in different directions from each
 other when being opened to be positioned at two positions between ends of
 the opening 3021a and outer peripheral ends of the cartridge body 3021
 respectively, so that the shutters are not positioned outside the
 cartridge body 3021.
 Thus, the effects not only that a disk can be accommodated without
 increasing the width of the cartridge body in the sliding direction, but
 also that the shutters are not positioned outside the cartridge beyond its
 outer peripheral end even when the opening is exposed in the state in
 which the shutters are opened can be obtained.
 The same effects can be obtained even when the present embodiment and the
 eighth embodiment are combined and, for example, either of the left or
 right shutter or both the shutters are formed of two upper and lower
 shutters.
 FIG. 67(A) illustrating a state in which the shutter is closed shows a
 configuration in which an end of the left shutter 3022 and an end of the
 right shutter 3025 are in contact with each other. However, the both
 shutters may overlap slightly each other (for example, about 1 mm).
 Particularly, the movement of each shutter can be controlled and ingress
 of dust or the like from the outside can be avoided by providing a
 hook-shaped bend at respective overlapping parts.
 As described above, in order to solve the problems in a conventional disk
 cartridge, the cartridge of the present invention has the configuration in
 which: for example, when the cartridge is inserted into a disk recording
 and reproducing unit and the shutters are moved, a part of the shutters is
 positioned outside the cartridge; the shutter is divided into two parts
 and the two shutter members are moved to the left and right; and the
 shutters are moved in one direction but are positioned one upon another
 after being moved. Therefore, the width of a region where the shutters are
 positioned after being moved can be decreased, thus decreasing the size of
 the cartridge itself
 In all the above-mentioned embodiments, an optical disk and a
 magneto-optical disk on which information is recorded and reproduced by
 the irradiation of light are illustrated as a disk of a recording medium.
 However, the recording medium is not always limited to those. Needless to
 say, the present invention also can be applied to a magnetic disk on which
 information is recorded and reproduced by the contact with a so-called
 magnetic head.
 Similarly, in all the above-mentioned embodiments, both surfaces of the
 cartridge body have an opening, which enables double-sided recording and
 reproducing in optical recording. When information is recorded on and
 reproduced from only one side, the opening may be provided to only one
 surface of the cartridge body. Subsequently, the shape of the shutter may
 be changed from the "U-shape" into an "L-shape" to be simplified. Further,
 it is not inevitable that the opening is provided so as to reach the
 center hole of the disk and thus the shutter covers the center hole. For
 example, the present invention can be applied to a disk cartridge, such as
 a 3.5-inch floppy disk, in which only a recording surface of a disk used
 for recording and reproduction is exposed from an opening and is covered
 by a shutter and a center hole required for rotating the disk is always
 exposed. In that case, it is better to provide a dustproof means between
 the vicinity of the center hole that is always exposed and the recording
 surface that is important for recording as required.
 In the seventh, eighth, and ninth embodiments, a return spring for
 returning a shutter means is provided inside the cartridge body. However,
 it is not always necessary to provide the spring inside the cartridge
 body. The sliding movement of the shutter means may be assisted by an
 opening/closing means (that is referred to as an opener lever in each
 embodiment) for opening and closing a shutter means of a disk recording
 and reproducing unit.
 As can be noticed from the above description, in the present invention, a
 cartridge is designed so that it is not required to provide the region
 where the shutter is positioned after being moved which width is wider
 than that of the opening, when the shutter of the cartridge is opened by
 being moved at the time of recording and reproduction. Therefore, an
 effect that the size of the cartridge body can be decreased according to
 an accommodated disk size, since it is not necessary to increase the width
 of the cartridge body in the sliding direction, even in the case where an
 accommodated disk has a small size, can be obtained.
 Each embodiment and example described above aims merely to disclose the
 technical contents of the present first to third inventions and therefore
 should not be considered as limiting. The present inventions can be
 carried out by modifying variously within the range described in claims
 without departing from the spirit of the present inventions. Therefore,
 the present inventions should be interpreted broadly.
 Industrial Applicability
 The present first invention enables information to be recorded on,
 reproduced and erased from a disk-type recording medium accommodated in a
 disk cartridge via an adapter in a drive unit designed for a larger disk
 cartridge than the disk cartridge. In addition, great modification in
 design of the drive unit is not required. Further, the disc-shaped
 recording medium can be loaded into the adapter without being touched.
 Therefore, the present invention enables, for example, recording of
 information on different disc-shaped recording media according to various
 standards in a single drive unit. The present invention can be applied
 extremely widely in an application field of disc-shaped recording media in
 which various standards coexist.
 According to the present second invention, a small and thin double-sided
 disk cartridge that can be used reversibly can be obtained, thus allowing
 the size and thickness of a drive unit to be decreased. Therefore, the
 present invention can be applied suitably, particularly to a disk
 cartridge for a drive unit that is required to be small and thin.
 According to the present third invention, a small disk cartridge whose size
 is set according to the size of an accommodated disk can be obtained.
 Therefore, the present third invention can be applied suitably,
 particularly to a disk cartridge that is required to have a small size
 The recording system of a disk to which the present first to third
 inventions can be applied is not especially limited. The present first to
 third inventions also can be applied to, for example, disks for an optical
 recording system, a magneto-optical recording system, a magnetic recording
 system, or other recording systems. In addition, the present first to
 third inventions can be applied not only to disks on which information can
 be recorded but also to disks from which information can be reproduced but
 on which information cannot be rerecorded, rewritten or overwritten.