Disk cartridge with releasable latching shutter

A pickup aperture provided in a surface of a cartridge body, a sliding shutter provided with a bent portion to be locked by which this aperture is opened and closed, and a locking member provided with a locking recess with which the bent portion to be locked is engaged when the sliding shutter is in a cover-closing position, to thereby lock the shutter. An unlocking pin-inserting bore is provided in the portion of the sliding shutter which is closer to the free end thereof than to the locking recess. When the shutter is in a cover-closing position, an unlocking pin, which is provided on the portion of an apparatus which corresponds to the unlocking pin-inserting bore, is inserted therein, so that the locking member is displaced to cause the bent portion to be locked and the locking recess to be disengaged from each other, the shutter being thus unlocked. The shutter-unlocking operation is carried out with the locking member left fixed. Owing to the unlocking pin, by which this unlocking operation is carried out, the shutter is moved in both the pickup aperture-opening direction and pickup aperture-closing direction.

TECHNICAL FIELD 
This invention relates to a disk cartridge rotatably accommodating a 
circular disk such as an opto-magnetic disk, optical disk or a magnetic 
disk, and provided with a sliding shutter for opening or closing pickup 
apertures formed in the cartridge body accommodating the disk, wherein the 
disk cartridge is so designed as to prevent the pickup apertures from 
being opened as a result of inadvertent opening of the shutter. 
BACKGROUND ART 
The disk cartridge of the prior art is comprised of a cartridge body made 
up of an upper half and a lower half abutted and connected to each other, 
and a circular disk rotatably accommodated within the cartridge body. 
Approximately at the center of the upper and lower sides of the 
disk-accommodating cartridge body, there are formed table insertion 
apertures confronted by a disk table of a disk driving device adapted for 
driving the disk into rotation and the pickup apertures confronted by a 
pickup writing or reading information signals to or from the disk, said 
pickup apertures being contiguous to said table insertion apertures and 
extending along the disk radius. A channel-shaped sliding shutter for 
opening or closing the table insertion apertures and the pickup apertures 
is adapted to be press-fitted from the front side of the cartridge body. 
The sliding shutter is so designed that, when it is in the cover-closed 
position covering the pickup apertures, the bent portion provided to the 
shutter as the locked member is locked by engagement with a locking recess 
in a locking member provided to the cartridge body in such a manner as to 
prevent dust deposition on or injury to the disk accommodated in the 
cartridge body otherwise caused by inadvertent opening of the pickup 
apertures. 
It may be contemplated to effect a cover-opening operation of the sliding 
shutter by a sliding operation after the bent portion to be locked is 
disengaged from the locking recess by resilient deflection of the locking 
member caused by an unlocking pin provided to the recording and/or 
reproducing device operatively connected to the disk cartridge. 
In the disk cartridge wherein unlocking is performed in the aforementioned 
manner, the amount of deflection of the locking member is changed with the 
position acted upon by the unlocking pin of the locking member. As a 
result, the thrust force applied to the resilient deflecting portion of 
the locking member which is designed with a predetermined resilient 
deflection is drastically changed so that a load in excess of the limit of 
mechanical strength may be applied to the resilient deflecting part thus 
occasionally causing destruction of the locking member. Even though the 
resilient deflecting part is not destructed in this manner, the locking 
function proper to the locking member is lost as a result of application 
of a load in excess of the threshold strength value. As a result, the 
pickup apertures are opened through inadvertent opening of the shutter 
resulting in destruction of the disk contained in the cartridge body 
through intrusion of dust and dirt or other impurities. 
It is therefore an object of the present invention to provide a disk 
cartridge wherein an unnecessary load is not applied to the shutter 
locking member except during the opening or closing operation for thereby 
assuring sufficient resilient deflection for a prolonged time, and wherein 
inadvertent cover-opening operation of the shutter is prevented to assure 
positive disk protection by providing a positive shutter locking. 
It is another object of the present invention to provide a disk cartridge 
in which a passage for a bent portion of the shutter is provided in the 
shutter locking member is an engaging recess of which said bent portion to 
be locked is engaged to lock the shutter. 
DISCLOSURE OF THE INVENTION 
The present invention resides in a disk cartridge comprising pickup 
apertures provided in the plane of the cartridge body, a sliding shutter 
having a bent portion to be locked, said bent portion opening or closing 
said pickup apertures, and a locking member having a locking recess in 
which said bent portion to be locked is engaged when said sliding shutter 
is in the cover-closing position for locking said shutter, there being 
formed in said sliding shutter an unlocking pin insertion aperture which 
is disposed closer to the free end side than the locking recess of said 
locking member when said sliding shutter is in the cover-closing position, 
whereby, when the unlocking pin provided from the recording and/or 
reproducing apparatus is inserted into the insertion aperture, the locking 
member is deflected to disengage the bent portion from the locking recess 
for unlocking the shutter. Thus the shutter unlocking operation may be 
attained with the locking member remaining fixed, while a movement in 
either directions of closing or opening the shutter is made possible by 
the unlocking pin designed to unlock the shutter. Since no load is applied 
to the locking member except during the time of opening or closing the 
shutter, the locking member is not deformed while the force of resilient 
deflection is maintained for a prolonged time for assuring positive 
shutter locking. 
In addition, in accordance with the present invention, a passage for the 
bent portion of the shutter is formed in the locking member in a locking 
recess of which the bent portion of the shutter is engaged to lock the 
shutter such that the locking and unlocking between the bent portion and 
the locking recess may be attained by only a small deflection of the 
locking member for assuring a smooth and reliable slide operation during 
the shutter locking and unlocking and during the sliding operation at the 
time of opening and closing the shutter, while the length of the bent 
portion and the depth of the locking recess may be selected to be 
sufficiently larger than the deflection of the locking member so as to 
assure more reliable shutter locking.

BEST MODE FOR EXECUTING THE INVENTION 
A disk cartridge according to the present invention will be hereafter 
explained by referring to the accompanying drawings. 
As shown in FIG. 1, the disk cartridge according to the present invention 
is mainly comprised of a cartridge body 4 made up of an upper half 1 and a 
lower half 2 in the shape of substantially flat square plates that are 
formed by molding from e.g. synthetic resin and are fixedly connected to 
each other by plural set screws 3, a circular disk, such as an 
opto-magnetic disk 5, rotatably accommodated within the main body 4, and a 
sliding shutter 8 adapted for opening or closing apertures 6, 7 formed in 
the upper half 1 and the lower half 2 of the cartridge body 4 and 
confronted by an optical pickup adapted for writing and reading 
information signals to and from the disk 5. 
The upper half 1 and the lower half 2 constituting the cartridge body 4 are 
designed in symmetry with each other except that mounting portions 9 for 
writing-safety members adapted for inhibiting writing to the disk 5 are at 
the same position such that the writing-safety members are mounted at 
opposite positions to each other when the upper half 1 and the lower half 
2 of the cartridge body 4 are abutted and connected to each other. 
Moreover, the upper half 1 and the lower half 2 are so designed as to 
define a space therebetween for rotatably accommodating the disk 5 when 
the upper and lower halves are abutted and connected to each other. The 
upper half 1 and the lower half 2 are formed with upright peripheral wall 
sections 10, 11 for defining a peripheral wall of the cartridge body 4 
when the wall sections are abutted and connected to each other, as shown 
in FIGS. 2A, 2B, 3A and 3B. The upper half 1 and the lower half 2 are 
formed with central disk table insertion apertures 12, 13 confronted by a 
disk table of a disk rotating device provided to the recording and 
reproducing apparatus for rotating the disk accommodated in the cartridge 
body 4. Contiguous to these disk table insertion apertures 12, 13 and 
radially of the disk 5, there are also formed, pickup apertures 6, 7 
confronted by the optical pickup and being of the same radius as the 
diameter of the disk table insertion apertures 12, 13. These apertures 6, 
7 are bored substantially in the form of rectangles extending from the 
center of the upper half 1 and the lower half 2 towards their front sides 
operatively connected to the shutter 8. On the inner surfaces of the upper 
half 1 and the lower half 2 and on a circumference of a circle that is 
centered about the disk insertion apertures 12, 13 and that is slightly 
larger than the outside diameter of the disk 5, there are projectedly 
formed a plurality of arcuate ribs 16, 17, that are designed to form a 
disk accommodating part and a position regulating wall regulating the 
horizontal position of the disk 5 when the ribs are abutted to each other. 
These arcuate ribs 16, 17 are formed at the respective corners of the 
upper half 1 and the lower half 2 and are of the same height as the 
upright wall sections 10, 11. 
In an area defined by the upright wall sections 10, 11 at the corners of 
the rear sides of the upper and lower halves 1 and 2 opposite to the front 
sides thereof operatively associated with the shutter 8, and by associated 
arcuate ribs 16, 17, there are formed each two mounting positioning 
reference apertures 18, 19; 20, 21 into which positioning pins provided to 
the recording and/or reproducing apparatus are fitted when the disk 
cartridge is mounted to the recording and/or reproducing apparatus so that 
these reference apertures are used for mounting positioning. The recording 
and/or reproducing apparatus is also provided with a pair of height 
positioning pins in opposition to these positioning pins for supporting 
the disk cartridge surface for setting the height position. 
At the corners of the upper half 1 and the lower half 2 where there are 
provided the other reference apertures 19, 21, there are provided writing 
safety member mounting sections 9, 9 laterally of these reference 
apertures 19, 21. In these writing-safety member mounting sections 9, 9, 
there are slidably mounted writing-safety members 22 provided with end 
writing safety portions 22a. When slid, the writing-safety member 22 
causes the position of the writing-safety portions 22a confronting to 
through-holes 9a, 9a of the mounting sections 9, 9 to be changed for 
realizing a writing inhibit state or a writing enable state as desired. 
On the other hand, in an area surrounded by the arcuate ribs 16, 17 and the 
upright wall sections 10, 11 at the corners on the front side operatively 
associated with the shutter 8 and on the rear side and in the vicinity of 
the reference apertures 18, 19; 20, 21 provided to the upper half 1 and 
the lower half 2, there are formed pairs of screw receiving portions 23, 
24; 25, 26 in which are threaded the set screws 3 for connecting and 
securing the upper half 1 and the lower half 2 to each other. 
The paired screw receiving portions 23, 24 provided in the vicinity of the 
reference apertures 18, 19; 20, 21 are formed by cylindrical boss-like 
formations 28, 29 projectedly provided to the inner surface of the lower 
half 2 and having bottomed screw holes 27 and receiving blocks 33, 34 for 
said formations having end recesses 30, 31 in turn having threaded 
through-holes and projectedly provided to the inner surface of the upper 
half 1 so as to be engaged by the ends of the boss-like formations 28, 29. 
The receiving recess 30 provided at the end of the receiving block 33 
constituting the screw receiving portion 23 has a circular contour with a 
diameter about equal to the end diameter of the formation 28 fitted 
therein so that the formation 28 has a light press fit therein for 
positioning fitting. 
The screw receiving portions 25, 26 provided to the front sides of the 
upper and lower halves 1 and 2 are formed by cylindrical boss-like 
formations 37, 38 projectedly formed on the inner surface of the lower 
half 2 and having bottomed screw threads 36, and by cylindrical boss-like 
formations 41, 42 projectedly formed on the inner surface of the upper 
half 1 and having threaded through-holes 39, wherein the boss-like 
formations 37, 38 and 41, 42 abut to one another. 
The upper and lower halves 1 and 2 provided with the screw receiving 
portions 23, 24; 25, 26 as described above are abutted and temporarily 
secured while also being positioned to one another with the disk 5 
accommodated therein and with the boss-like formations 28, 29 of the screw 
receiving portions 23, 24 on the sides of the reference apertures 18, 19; 
20, 21 being press-fitted in the receiving recesses 30, 31 of the 
receiving blocks 33, 34. By threading the set screws 3 into these screw 
receiving portions 23, 24 and the screw receiving portions 25, 26 at the 
front sides, there is securely completed the cartridge body 4 in which the 
disk 5 is rotatably accommodated, as shown in FIG. 4. 
In addition, on the outer surfaces along the front sides and edges of the 
upper and lower halves 1 and 2 where there are formed the apertures 6 and 
7, there are formed guide grooves 44, 45 adapted for sliding and guiding 
the shutter 8 adapted for opening and closing the apertures 6 and 7. 
The shutter 8 which is provided in opposition to the upper and lower 
surface of the main body 4 and slidably mounted by the intermediary of the 
guide grooves 44, 45, is formed by bending a metal plate, such as a 
stainless steel plate, in the form of a channel, as shown at A, B and C in 
FIG. 5. Thus the shutter 8 is made up of an upper shutter portion 47 and a 
lower shutter portion 48 bent from both sides of a common junction portion 
46 and being of a sufficient extent to cover the aforementioned apertures 
6 and 7 and the disk insertion apertures 12 and 13 simultaneously, with a 
sliding guide 49 being constituted by junction portions of the upper and 
lower shutter portions 47 and 48 to the junction portion 46 and by the 
junction portion 46. The sliding guide 49 is extended further in the 
direction of the guide grooves 44, 45 from one sides of the upper shutter 
portion 47 and the lower shutter portion 48. Thus the shutter 8 has a 
contour substantially in the shape of a letter L when seen in plan, as 
shown at A in FIG. 5. 
At the both ends of the sliding guide 49 of the shutter 8, there are formed 
paired guide pieces 50, 52 on the upper and lower sides thereof and in 
opposition to each other, these guide pieces being formed by cutting and 
inwardly bending portions of the slide guide 49 and being guided in 
engagement with the aforementioned guide grooves 44, 45. As shown at C in 
FIG. 5, these guide pieces 50, 52 are bent in the form of a letter L when 
seen in cross-section, and are of a width approximately equal to the width 
of each of the guide grooves 44, 45, with the forward parts thereof bent 
outwards. The guide pieces 50, 52 formed in this manner are engaged in the 
guide grooves 44, 45 for preventing the shutter from being extricated from 
the cartridge body 4. 
Between the paired guide pieces 50 and 52, there are formed ribs 54, 55 by 
drawing in order to prevent the sliding guide from being bent or flexed in 
the longitudinal direction or in the direction of thickness as a result of 
the sliding guide 49 being elongated relative to the width of the upper 
and the lower shutter portions 47, 48. 
The junction piece 46 of the shutter 8 is formed with a bent portion 57 by 
partial cutting and erecting, said bent portion being engaged by a locking 
member 56 for the shutter 8 provided to the cartridge body 4 when the 
shutter 8 is in the closure position. The junction portion 46 also has an 
insertion aperture 58 in which is inserted an unlocking pin 68 provided 
from the recording and/or reproducing apparatus as later described. The 
foremost side corner of the bent portion 57 is arcuate to permit smooth 
sliding. The unlocking pin insertion aperture 58 is positioned at the free 
end side of the locking member 56 and in proximity to the bent portion 57. 
On the forward side faces of the upper half 1 and the lower half 2 along 
which slides the sliding guide 49 of the shutter 8 are formed slide 
recesses 59, 60 defining a slide groove 43 along which slide the bent 
portion 57 to be locked and the unlocking pin 68. The upper half 1 and the 
lower half 2 are formed with resilient deflection tabs 61, 62; 63, 64 
defined by forming slots opening on the front side face from the guide 
grooves 44, 45 so as to be in register with the guide pieces 50, 52 of the 
shutter 8. The outer face sides of these deflection pieces 61, 62; 63, 64 
are tapered to provide for facilitated insertion of the guide pieces 50, 
52 into the guide grooves 44, 45. As the shutter 8 is fitted to the 
forward side face of the main body 4 with the guide pieces 50, 52 in 
register with the resilient deflection pieces 61 62; 63, 64, these 
deflection pieces are flexed by the guide pieces 50, 50; 52, 52. Thus the 
shutter 8 is slidably mounted as shown in FIG. 6 with the guide pieces 50, 
52 easily engaging in the guide grooves 44, 45 for opening or closing the 
apertures 6, 7. 
From the front to the outer side faces of the upper half 1 and the lower 
half 2, there are formed recesses 65, 66 delimiting the extent of the 
sliding of the shutter 8, as shown at B, C in FIG. 2 and B, C in FIG. 3. 
To a corner on the front inner sides of the upper half 1 is attached the 
locking member 56 molded from synthetic material and having a locking 
recess 67 into which the bent portion 57 is engaged for locking the 
shutter 8 when the shutter 8 is in a position of closing the apertures 6, 
7 of the cartridge body 4. As shown in FIG. 7, this locking member 56 is 
molded from synthetic resin and formed as an extension through a thrusted 
portion 73 and a semicircular resilient deflecting portion 72 from one end 
of a mounting base portion 71 having through-holes 70, 70 adapted to be 
engaged by a pair of attachment pins 69, 69 implanted on the inner surface 
of the upper half 1, said thrusted portion being thrusted by the unlocking 
pin described above. The locking recess 67 to be engaged by the bent 
portion 57 of the shutter 8 is formed halfway on one side of the thrusted 
portion 73. On the surface of the thrusted portion 73 abutted by the 
unlocking pin, and at a position closer to the free end of the locking 
member than the locking recess 67, there is formed an adjustment recess 78 
for adjusting the thrust given by the locking member, as shown in FIGS. 8 
and 9, said recess being an inclined surface gradually inclined with down 
ward gradient towards the deflecting portion 72. On said surface is also 
formed a slit-like passage 74 into which the bent portion 57 is 
intrudingly passed upon sliding operation of the shutter 8. This passage 
74 is formed as a slot having a depth and a width so selected that the 
bent portion 57 does not touch the groove sides during sliding of the 
shutter 8. The passage 74 is also formed with a width lesser than the 
diameter of the unlocking pin 68 provided to the recording and/or 
reproducing apparatus for thrusting the locking member 56 so that the 
unlocking pin 68 when thrusting the locking member 56 is not intruded into 
the passage 74. 
It will be noted that, by shifting the trajectory of the unlocking pin 68 
away from the passage 74, the passage 74 can be formed with a width larger 
than the unlocking pin 68. 
An inclined portion 75 is formed on one side of the free end of the locking 
member 56, in such a fashion that, when the locking member is acted upon 
by the unlocking pin 68 provided by the recording and reproducing 
apparatus, the locking member is gradually resiliently deflected so as to 
be then returned gradually resiliently to its former position. Although 
the inclined portion 75 is formed as a straight inclined surface in the 
present embodiment, it may also be curved arcuately. 
There is projectedly provided halfway on the opposite side of the thrusted 
portion 73 a substantially L-shaped engaging portion 77 that is engaged 
with an engaging portion 76 formed by partially removing the upright wall 
section 10 on the front lateral side of the upper half 1 for regulating 
any excess resilient deflection towards the free end and also for 
regulating resilient deflection of the thrusted portion 73 towards the 
outside of the cartridge body 4 for thereby protecting the locking member 
56. 
The locking member 56 formed as described above is mounted as shown at A in 
FIG. 2 with the deflecting portion 72 disposed within the slide recess 59 
and with the mounting base portion 71 being engaged by mounting pins 69, 
69 through engaging apertures 70, 70. 
The locking and unlocking operations for the locking member 56 by the 
shutter 8 in the above described disk cartridge is hereafter explained. 
When the disk cartridge is mounted to the recording and/or reproducing 
apparatus, the unlocking pin 68 provided to the apparatus is intruded into 
the cartridge body 4 through the unlocking pin insertion aperture 58 for 
thrusting the portion 73 of the locking member 56 as shown in FIG. 11 into 
resilient deflection. When the portion 73 is thrusted in this manner, the 
bent portion 57 of the shutter 8 is disengaged from the locking recess 67. 
Then, with the unlocking pin 68 remaining engaged in the unlocking pin 
insertion aperture 58, the shutter 8 is slid in the cover-opening 
direction. As the shutter 8 approaches the inclined portion 75 of the 
thrusted portion 73, the bent portion 57 confronts to the passage 74. When 
the unlocking pin 68 comes to a position slightly above the inclined 
portion 75, the locking member 56 is resiliently returned to its former 
position. The bent portion 57 is intruded into the passage 74 and the 
shutter 8 is slid in this state for opening the pickup apertures 6, 7, as 
shown in FIGS. 12. 
The cover-closing operation of the shutter 8 that has opened the apertures 
6, 7 for opening the cover is performed by the reverse of the procedure 
described in the foregoing. First of all, when the shutter 8 is slid 
towards the locking member 56, the bent portion 57 intrudes into the 
passage 74, the unlocking pin 68 then riding on the inclined portion 75 
for gradually flexing the locking member 56. As the shutter 8 is moved 
until the unlocking pin 68 arrives at a position overlying the thrusted 
portion 73 to cause the locking member 56 to be significantly flexed as 
shown in FIG. 11, the bent portion 57 is shifted to a position in register 
with the locking recess 67. When the unlocking pin 68 is extracted from 
the insertion aperture 58, the locking member 56 is resiliently returned, 
with the bent portion 57 engaging in the locking recess 67 to lock the 
shutter 8. 
It should be noted that, with the locking member 56 having its free end 
side formed as the thrusted portion 73, as described above, the amount of 
deflection differs as a function of the thrusting position so long as the 
amount of intrusion of the unlocking pin 68 into the cartridge member 4 
remains constant. When the relative thrust position on the portion 73 by 
the unlocking pin 68 is changed and the portion 73 is thrusted at the 
resilient deflection portion 72, as indicated by the dotted line in FIG. 
10, it is deflected more pronouncedly than when it is thrusted at the free 
end side. In the disk cartridge of the present invention, however, since 
the adjustment recess 78 inclined from the free end side towards the 
resilient reflecting side 72 is provided so that, when the unlocking pin 
68 thrusts the portion 73 at a point closer to the deflecting portion 72 
than the predetermined normal position, the amount of the thrusting 
applied to the thrusted portion 73 is adjusted by virtue of the provision 
of the recess 78 so that the deflecting portion 72 may be prevented from 
being deflected in more than a predetermined amount. That is, the further 
the thrusting position of the unlocking pin 68 is shifted away from the 
normal thrusting position towards the resilient deflecting portion 72, the 
deeper becomes the adjustment recess 78, in order to absorb the difference 
in deflection of the thrusted portion 73 caused by the deviation in the 
thrusting position by the unlocking pin 68. 
It will be noted that, since the adjustment recess 78 is designed to absorb 
any excess deflection of the locking member 56 for thereby protecting the 
resilient deflecting portion 72, the adjustment recess may be formed, as 
shown in FIG. 13 as a recess 178 having a constant depth for an area 
substantially in register with the position at which a load in excess of 
the limit strength value may be applied to the resilient deflecting 
portion 72. 
It is to be noted that the adjustment recess 178 is designed with a depth 
to cause a deflection of the locking member 56 to induce a deflection 
sufficient to disengage the bent portion 57 of the shutter 8 from the 
locking recess 57 when the unlocking pin 68 thrusts the adjustment recess. 
Industrial Utilizability 
According to the present invention, when the sliding shutter is in the 
cover-opening position, the insertion opening for the shutter unlocking 
pin is located closer to the free end side than the locking portion of the 
locking member and, as the unlocking pin provided to the recording and/or 
reproducing apparatus is introduced through the insertion opening for the 
unlocking pin, the locking member is deflected to effect unlocking. As the 
unlocking pin is moved, the shutter is separated from the locking member 
and moved along with the unlocking pin in both directions for opening and 
closing the pickup apertures. 
Hence, no load is applied to the locking member except during the shutter 
opening and closing time so that sufficient resiliency may be maintained 
for a prolonged time without deforming the locking member for assuring 
positive shutter locking. Any inadvertent opening of the pickup apertures 
may be avoided to assure a positive disk protection. 
In addition, the unlocking pin abuts on a portion closer to the free end 
side than the shutter locking recess, the resilient deflection of the 
locking member is facilitated to provide for smooth engagement of the bent 
portion of the shutter in the locking recess while allowing to reduce the 
unlocking force provided by the unlocking pin. 
Therefore, the present invention may be advantageously applied to a disk 
cartridge rotatably accommodating a circular disk such as an opto-magnetic 
disk, an optical disk or a magnetic disk, wherein there are provided a 
sliding shutter for opening and closing pickup apertures in the cartridge 
body accommodating the disk and a mechanism for locking the shutter.