1. Field of the Invention
This invention relates to a disc cartridge comprised of a cartridge main body and a disc, such as an optical disc, which is housed therein and which is capable of recording information signals, such as music or video signals. More particularly, it relates to such a disc cartridge in which a shutter member is moved in a direction parallel to the direction of insertion of the disc cartridge into a recording/reproducing apparatus for opening or closing an opening formed in the cartridge main body.
2. Background of the Invention
The disc cartridge has hitherto been employed which is comprised of the cartridge main body and a disc, such as an optical disc or a magneto-optical disc, which is housed therein and which is capable of recording information signals, such as music or video signals.
There has been proposed the disc cartridge of the above kind in which a shutter member for closing an aperture formed in the disc cartridge for radially exposing at least a part of a signal recording region of the disc, housed within the cartridge main body exposed to the outside, is moved in a direction parallel to the direction of inserting the disc cartridge into the recording/reproducing apparatus for opening or closing the aperture. Above mentioned disc cartridge D1, as shown in FIGS. 1 and 2, include a cartridge main body accommodating an optical disc or a magneto-optical disc. The cartridge main body is comprised of an upper half 1 and a lower half 2 abutted and connected to each other.
At a mid part on the lower surface of the cartridge main body 3 housing the disc table of a disc rotating and driving device may be intruded for rotating the disc 4 when the disc cartridge D1 is loaded in the recording and/or reproducing apparatus. The opening 5 is faced by the rim of a center opening 4a of the disc 4 and a magnet-clamping magnetic plate 4b attached to the disc 4 for closing center opening 5.
The upper and lower surfaces of the cartridge main body 3 are formed with signal recording/reproducing apertures 6, 7 for exposing at least a part of the signal recording region of the disc 4 accommodated therein to the outside. These signal recording/reproducing apertures 6, 7 are rectangular in contour and disposed at the transversely mid position of the cartridge main body 3 for extending from a position proximate to the opening 5 to a position reaching the front side of the cartridge main body 3.
A shutter member 8 for opening and closing the signal recording/reproducing aperture 6, 7 is mounted for movement on the cartridge main body 3. The shutter member 8 is formed by punching and bending a metal plate, such as a thin stainless steel plate, and in the shape of a letter U. The shutter member includes shutter sections 8a, 8b for closing the apertures 6, 7, and connecting web 8c connecting the shutter sections 8a,8b to each other. First and second movement guide section 9, 10 in the form of a letter U are formed adjacent to both ends of the connecting web 8c of the shutter member 8 for stable guidance of the shutter member 8 in a direction parallel to the front side of the cartridge main body 3. Extrication proof guide lugs 11, are formed by bending a part of the first and second movement guide sections 9, 10.
The shutter member 8, arranged as above, is fitted on the front side of the cartridge main body 3 as shown in FIGS. 1 and 2, with the shutter sections 8a, 8b extending over the signal recording/reproducing apertures 6, 7. At this time, extrication-proof guide lugs 11, 11 are engaged with extrication-proof guide grooves 12 formed in the cartridge main body 3, while the first and second movement guides 9, 10 are fitted on the front end face of the lower half 2. The shutter member 8 is prevented from being extricated from the cartridge main body 3 and from being wobbled by the first and second movement guide sections 9, 10 as the shutter member is moved in the thus stabilized state in the directions shown by arrows A and B in FIG. 1 of opening or closing the signal recording/reproducing apertures 6, 7.
A locking member 13 is arranged within the cartridge main body 3 for holding the shutter member 8 in the position of closing the signal recording/reproducing apertures 6, 7 when the shutter member 8 has reached the position of closing the signal recording/reproducing apertures 6, 7. The locking member 13 is comprised of a proximal part 13a pivotally mounted within the cartridge main body 3 and a resiliently flexible locking arm 13b extended from the proximal part 13a. The locking arm 13b has an engaging recess 15 engaged by a mating locking member 14 formed by bending a part of the first movement guide section 9 of the shutter member 8. When the shutter member 8 closes the signal recording/reproducing apertures 6, 7, the shutter member is locked in the close position by the mating locking member 14 engaged with the engaging recess 15.
The front side of the cartridge main body 3 along which is moved shutter member 8 is formed with a groove 16 for unlocking the locking member 13 which locks the shutter member 8 in the aperture closing position and for being engaged by a shutter opening member arranged in the recording and/or reproducing apparatus for moving the shutter member 8 in the direction of opening the signal recording/reproducing apertures 6, 7. The groove 16 has an opening end 16a on the lateral surface 3b extending at right angles to the front side 3a of the cartridge main body 3 along which is moved the shutter member 8. By forming the groove 16 in this manner, the shutter opening member may be introduced into the groove from its opening end opened on the lateral surface 3b of the cartridge main body 3 for resiliently deflecting the locking arm 13b of the locking member 13 for unlocking shutter member 8 from its position of closing the apertures 6, 7 for moving the shutter member 8 in the direction of opening the apertures 6, 7.
Referring now to FIGS. 5 and 6, by arranging the disc cartridge D1 as described above, the shutter member 8 may be moved simply by providing the recording and/or reproducing apparatus with a convex-shaped shutter opening member introduced into the groove 16. That is, a convex-shaped shutter opening member is provided on the lateral side of a cartridge holder into which the disc cartridge D1 is introduced and held and which is adapted for loading the disc cartridge D1 into the disc rotating and driving device. The disc cartridge D1 is introduced into the cartridge holder, with the lateral side of the disc cartridge D1 having the opening end 16a of the groove 16 as an introducing end and with the direction of movement of the shutter member 8 as the introducing direction. In this manner, the disc cartridge D1 may be introduced into the groove 16 to permit the shutter member 8 to be moved in the direction of the opening the apertures 6 and 7 by the shutter member 8.
Meanwhile, the cartridge holder 20, provided with the shutter opening member 21 producing the movement of the shutter member 8 of the disc cartridge D1 and causing the disc cartridge D1 to be loaded in the disc rotating and driving device 22, is arranged within the recording and/or reproducing apparatus vertically movably with respect to the disc driving and rotating device.
When in an eject state permitting the disc cartridge D1 to be introduced therein, the cartridge holder 20 is maintained at an elevated position spaced from the disc table 23 of the disc rotating and driving device, as shown in FIG. 5. When the disc cartridge D1 is introduced into the cartridge holder 20, the cartridge holder is lowered towards the disc rotating and driving device 22. When the cartridge holder 20 is lowered towards the disc rotating and driving device 22, the disc cartridge D1 held by the cartridge holder 20 is also lowered towards the disc rotating and driving device 20. The disc table 23 of the disc rotating and driving device 22 is introduced at this time into the inside of the cartridge main body 3 via the opening 5, as shown in FIG. 6, and the disc 4 housed within the cartridge main body 3 is set on the disc table 23, at the same time that the disc 4 is clamped for rotation in unison with the disc table 23.
When the cartridge holder 20 is lowered towards the disc rotating and driving device 22, the disc cartridge D1 is supported by loading height position setting pins 25, and loading position setting pins 26, and by a cartridge thrusting rib 27 (shown in FIGS. 7 and 8) is mounted upright on a chassis base plate 24 within the recording and/or reproducing apparatus. One of the loading height setting pins 25 and one of the loading position setting pins 26 are not shown in FIGS. 5 and 6. The disc cartridge D1 is thrust and supported at this time by the loading height position setting pins 25 and the loading position setting pins 26 and by the cartridge thrusting rib 27 provided on an inner upper surface of the cartridge main body 3 facing an upper major surface 3c of the cartridge main body 3, as shown in FIG. 6. The disc cartridge D1, thrust by the cartridge holder 20 towards the disc rotating and driving device below and supported by the loading height position setting pins 25 and the loading position setting pins 26, is positioned in the vertical direction and in the horizontal direction and loaded in this state within the recording and/or reproducing apparatus. Meanwhile, the loading position setting pins 26, are engaged in positioning holes 17, 18 (shown in FIGS. 3 and 4) bored in the lower major surface 3d of the cartridge main body 3.
Meanwhile, if the disc cartridge D1, introduced into and held by the cartridge holder 20 and supported by the loading height setting pins 25 and the loading position setting pins 26 provided within the recording and/or reproducing apparatus, is to be loaded within the recording and/or reproducing apparatus by being positioned by the loading height position setting pins 25 and the loading position pins 26, it is necessary for the upper major surface 3c of the cartridge main body 3 to be positively thrust and supported by the cartridge thrusting rib 27 provided on the cartridge holder 20. Simultaneously it is also necessary for the disc cartridge D1 to be pressed and supported by the loading height setting pins 25 and the loading position setting pins 26 under the thrusting force exerted by the cartridge holder in the descending direction.
In order for the disc cartridge D1 to be pressed against and supported by the loading height setting pins 25 and the loading position setting pins 26 under the thrusting force exerted by the cartridge holder 20, it is necessary for the disc cartridge D1 to be supported by the loading height setting pins 25 and the loading position setting pins 26, while it is also necessary for the cartridge holder 20 to be moved subsequently in the descending direction.
When the disc cartridge D1, which is so arranged that the shutter opening member 21 is intruded into the groove 16 formed on the front surface 3a of the cartridge main body 3, is introduced into and held by the cartridge holder 20, the shutter opening member 21 has been introduced into the groove 16. Thus the groove 16 needs to be of such a width as to permit the cartridge holder 20 to descend in order to get the disc cartridge D1 to be pressed against and supported by the loading height setting pins 25 and the loading position setting pins 26.
That is, when the disc cartridge D1 is introduced into the cartridge holder 20 in its raised position and is not pressed against or supported by the loading height setting pins 25 or by the loading position setting pins 26, but is supported by a lower cartridge support 20a of the cartridge holder 20, as shown in FIG. 7, it is necessary to maintain a gap W1 between the shutter opening member 21 and a lower surface 16a of the groove 16 which is wide enough to permit the cartridge holder 20 to be lowered until the disc cartridge D1 is pressed against and supported by the loading height setting pins 25 and the loading position setting pins 26. By maintaining the gap W1 to permit the descent of the cartridge holder 20, the disc cartridge D1 is thrust and supported by the thrusting rib 27 and positioned by the height setting pins 25 and the loading position setting pins 26 so as to be loaded in the recording and/or reproducing apparatus Unless the gap W1 wide enough to permit the cartridge holder 20 to be lowered, is maintained between the shutter opening member 21 and the lower surface 16a of the groove 16, the shutter opening member 21 is abutted against the surface 16a of the groove 16 so that the disc cartridge D1 cannot be pressed by the thrusting rib 27 into pressure contact with the height setting pins 25 and the loading position setting pins 26. The result is that the disc cartridge D1 cannot be positioned within the cartridge holder 20 within the recording and/or reproducing apparatus.
In order for the disc cartridge D1 to be supported by the height setting pin 25 and the loading position setting pin 26, under the urging pressure in the descending direction of the cartridge holder 20, it is necessary that the gap W1, shown in FIG. 7, defined between the shutter opening member 21 and the surface 16a of the groove 16, be larger than the gap W2 between the upper major surface 3c of the cartridge main body 3 and the thrusting rib 27. For maintaining such magnitude relation between the gap W1 and W2, it is necessary to increase the width W3 of the groove 16.
However, if the width W3 of the groove 16 is increased, forward end parts 1a, 2a defining the groove 16 of the upper and lower halves 1, 2 of the cartridge main body 3 at least are reduced in thickness. If the disc cartridge D1 is subjected to impacts, such as by descent, the cartridge main body 3 may be damaged easily, so that the disc 4 accommodated therein cannot be protected sufficiently.
It may be contemplated to improve machining accuracy of the cartridge main body 3 and the cartridge holder 20 maintain the magnitude relation of the gap W1 between the shutter opening member 21 and the lower surface 16a of the groove 16 being larger than the gap W2 between the upper major surface 3c of the cartridge main body 3 and the cartridge thrusting rib 27 to reduce the width W3 of the groove 16 towards small a value as possible so as to provide the disc cartridge D1 having the cartridge holder 20 with a sufficient mechanical strength, with the forward ends 1a, 2a of the upper and lower halves 1, 2 defining the groove 16 each being of an increased thickness.
However, since the cartridge main body 3 of the disc cartridge D1 is made up of the upper half 1 and the lower half 2 which are molded of synthetic resin and which are abutted and connected to each other, it is extremely difficult to fabricate the cartridge main body 3 with extremely high dimensional accuracy.
The same may apply when the cartridge holder 21 is fabricated by a molded body of a synthetic resin.