Door opening-and-closing mechanism of recording/reproducing apparatus

A door opening-and-closing mechanism of a recording/reproducing apparatus including a door axially supported at the back side of a front face plate so as to be capable of opening and closing an opening, and a lock member for preventing free rotational movement of the door. The lock member includes a supporting shaft rotatably supported at the back side of the front face plate, lock portions which engage and disengage the door, and a portion to be pushed that projects into the opening, which are formed into an integral structure. The portion to be pushed is pushed by a disk cartridge being inserted in order to disengage the lock portions and the door from each other.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a recording/reproducing apparatus for 
performing recording/reproducing operations by inserting a cartridge 
containing a recording medium, such as a magnetic disk, into the 
apparatus, and, more particularly, to a door opening-and-closing mechanism 
for opening and closing an opening used for inserting a cartridge. 
2. Description of the Related Art 
A door opening-and-closing mechanism is widely used in, for example, a 
magnetic recording/reproducing apparatus for performing 
recording/reproducing operations of information on a magnetic disk 
contained in a disk cartridge. The door opening-and-closing mechanism 
prevents entry of foreign matter, such as dust, into the apparatus from an 
opening by a door provided at the opening for inserting a disk cartridge 
therein, when the disk cartridge is not loaded. 
As disclosed, for example, in Japanese Unexamined Patent Publication No. 
63-200386, in a conventionally known door opening-and-closing mechanism, a 
plate-shaped door is rotatably supported at the front face plate with an 
opening, and biased toward the closing direction of the opening by means 
of a torsion coil spring. In such a prior art door opening-and-closing 
mechanism, the opening is closed by the door, when the disk cartridge is 
not loaded. During insertion of the disk cartridge into the apparatus from 
the opening, the door is pushed by the disk cartridge and rotated, causing 
the disk cartridge to be loaded in position. Ejection of the disk 
cartridge out the apparatus causes rotation of the door in the opposite 
direction due to the biasing force of the torsion coil spring, whereby the 
door is re-closed. 
The above-described conventional shutter opening-and-closing mechanism has 
the following problems. When the door is accidentally contacted by the 
operator with, for example, his finger or a writing material, the door is 
easily opened, allowing the entrance of foreign matter into the apparatus, 
since the door is biased in the closing direction of the opening merely by 
the torsion coil spring. In addition, in the game machine field or the 
like, disk cartridges of various sizes and shapes are sometimes used. In 
such a case, when the above-described conventional shutter 
opening-and-closing mechanism is used, the door is easily opened by disk 
cartridges which are not of the regular type, so that failure of the 
mechanism in the apparatus results due to accidental insertion of a disk 
cartridge which is not of the regular type. 
SUMMARY OF THE INVENTION 
Accordingly, an object of the present invention is to provide a locking 
means which prevents rotational movement of a door, when a cartridge is 
not loaded, and which is actuated by the cartridge, which is being 
inserted, to unlock the door. With such a locking means actuated by a 
cartridge, when an attempt is made to insert a regular type cartridge into 
the opening, the locking means is unlocked, which opens the door to allow 
insertion of the cartridge into the apparatus. On the other hand, when an 
attempt is made to insert a cartridge which is not of the regular type, 
the locking means remains locked to prevent rotational movement of the 
door, which reliably keeps out foreign matter from the opening. 
To this end, according to the present invention, there is provided a door 
opening-and-closing mechanism of a recording/reproducing apparatus, which 
comprises a front face plate with an opening for inserting a cartridge, a 
door rotatably supported at the back side of the front face plate, an 
elastic member for biasing the door in the closing direction of the 
opening, and locking means for preventing rotational movement of the door. 
The locking means is provided with a lock portion engaging and disengaging 
the door, and a portion to be pushed extending into the opening. The 
cartridge, when being inserted, pushes the portion to be pushed to thereby 
disengage the lock portion and the door from each other. 
Any locking means may be used as long as the locking means comprises the 
aforementioned lock portion and the aforementioned portion to be pushed. 
When the lock portion and the portion to be pushed are integrally formed 
with a supporting shaft, and the supporting shaft is rotatably supported 
at the back side of the front face plate, it is possible to simplify the 
task of assembling the locking means, in addition to simplifying the 
structure of the locking means. 
In addition, when a cutout is formed in a portion of the peripheral face of 
the supporting shaft, and an anti-removal portion overlapping the 
peripheral face of the supporting shaft and a projection formed so as to 
be disposed within the cutout are formed at the back side of the front 
face plate, the supporting shaft can easily be incorporated into the 
anti-removal portion using the cutout. Thus, after assembly, the 
supporting shaft is reliably prevented from being removed from the back 
side of the front face plate by the anti-removal portion and the 
projection. 
When a stopper is provided for preventing movement of a rotary shaft, 
rotatably supporting the door in the recording/reproducing apparatus, in 
the direction of insertion of the cartridge, it is possible to hold the 
door in the closing position by the locking means and the stopper to 
thereby reliably prevent breakage of the door, even in the case where the 
door is pushed by a cartridge which is not of the regular type. 
When a projection projecting into the opening is provided at the front face 
plate, and a portion to be pushed of the locking means is disposed 
therearound, the aforementioned projection can prevent a cartridge which 
is not of the regular type from pushing the portion to be pushed, during 
an attempted insertion of the cartridge into the opening, so that 
insertion of a cartridge which is not of the regular type can be 
prevented. 
When a taper which inclines in the direction of insertion is formed on the 
portion to be pushed, the portion to be pushed is pushed by the cartridge, 
while it is being inserted, at the taper, thus allowing smooth actuation 
of the locking means.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
A description will now be given of a preferred embodiment of the present 
invention, with reference to the drawings. 
Referring to FIGS. 1 and 2, an opening 2 is formed in a front face plate 1 
formed of synthetic resin. The front face plate 1 is snappingly secured to 
a holder 3 and a chassis 4 disposed in the magnetic recording/reproducing 
apparatus. The front face plate 1 has a pair of projections 1a that 
project downward from the upper boundary defining the opening 2. Second 
projections 1b are formed inwardly of the sides of the first projections 
1a. 
As shown in FIG. 3, the disk cartridge 5, used in the above-described 
magnetic recording/reproducing apparatus, has a cartridge case 6 formed of 
a hard synthetic resin, a magnetic disk (not shown) rotatably accommodated 
in the cartridge case 6, and a shutter (not shown) disposed so as to be 
capable of reciprocative movement along the lower surface of the cartridge 
case 6. Recesses and protrusions are formed at the upper surface of the 
cartridge case 6, with pushing protrusions 6a formed on both sides of the 
case 6. A pair of protuberances 6b, 6c are formed between both pushing 
protrusions 6a. Recessed portions 6d between the pushing protrusions 6a 
and the protuberance 6b are formed in correspondence with the first and 
second protrusions 1a and 1b at the front end face of the cartridge case 
6, whereas the recessed portions between the pushing protrusions 6a and 
the protuberance 6c are formed only in correspondence with the first 
projections 1a. Therefore, when the disk cartridge 5 is properly inserted 
into the opening from the front end, the disk cartridge 5 is inserted in 
position, without contacting the first and second projections 1a and 1b. 
On the other hand, when an attempt is made to insert the disk cartridge 5 
from its rear end, the second projections 1b come into contact with the 
protuberance 6c, which prevents insertion of the disk cartridge 5 into the 
opening 2. 
A plate-shaped door 7 is disposed on the back side of the front face plate 
1. Rotary shafts 7a are integrally formed with the door 7 at each of the 
lower ends thereof. Clearance holes 7b are formed in the door 7. The 
rotary shafts 7a are rotatably supported at the back side of the front 
face plate 1, one of which has a torsion coil spring 8 wound therearound. 
Both of the ends of the torsion coil spring 8 are retained by the door 7 
and the back side of the front face plate 1, respectively. The door 7 is 
biased in the closing direction of the opening 2 due to the elasticity of 
the torsion coil spring 8. As shown in FIG. 2, a stopper portion 9 is 
provided behind each rotary shaft 7a. Although in the present embodiment, 
the stopper portions 9 are integrally formed with the chassis 4, they may 
be formed on a different component part in the magnetic 
recording/reproducing apparatus. The stoppers 9 function to prevent 
movement of the rotary shafts 7a in the direction of insertion of the 
cartridge (in the direction of the arrow in FIG. 2), but do not interfere 
with the rotational movement of the door 7 by moving into the clearance 
holes 7b. 
A pair of lock members 10 are disposed at the back side of the front face 
plate 1 in order to prevent free rotational movement of the door 7. As 
shown in FIG. 5, each lock member 10 comprises a supporting shaft 10a with 
a pair of cutouts 11 formed in its outer peripheral surface, a pair of 
lock portions 10b and 10c integrally formed with both ends of the 
supporting shaft 10a, and a protrusion 10d to be pushed extending from and 
perpendicular to the lock portion 10b. The protrusion 10d has a chamfered 
taper 10e. A thick lateral projection 1c is formed at the back side of the 
front face plate 1, and extends along the peripheral edge of the opening 2 
up to the boundary between it and the recesses 1d on both upper ends 
defining the opening 2. A pair of anti-removal portions 1e are formed at 
locations directly opposite to those portions of the lateral projection 1c 
at corresponding locations to the first and second protrusions 1a and 1b. 
Short protrusions 1f are formed on both sides of these anti-removal 
portions 1e. The insides of the anti-removal portions 1e are curved into 
recesses having substantially the same shape as the supporting shaft 10a. 
In the same way, the portion opposing each protrusion if is curved into a 
recess having substantially the same shape as the supporting shaft 10a. 
The lock members 10 are incorporated at the back side of the front face 
plate 1. When the ends of the torsion coil spring 12 wound around the 
supporting shaft 10a are retained near the lock portions 10c and the upper 
portion of the front face plate 1, the lock portions 10b and 10c are 
biased in the direction in which they are retained by the upper ends of 
the door 7 with respect to the supporting shaft 10a as a rotational 
supporting point. Such a lock member 10 is incorporated by the following 
procedure. As shown in FIG. 6A, the cutouts 11 of the lock member 10 are 
pushed in the direction of arrow a, while they are kept in opposing 
relationship to their corresponding protrusions if of the front face plate 
1, followed by insertion of the supporting shaft 10a into the anti-removal 
portions 1e. Then, at the moment the supporting shaft 10a contacts the 
inner sides of each of the anti-removal portions 1e, the lock member 10 is 
rotated 90 degrees in the direction of arrow b, causing the protrusion 10d 
to be pushed to move into its associated recess 1d and project into the 
opening 2. As shown in FIG. 6B, the lock member 10 is rotatably 
incorporated at the back side of the front face plate 1. When the lock 
member 10 is set in a state shown in FIG. 6B, the anti-removal portions 1e 
prevent movement of the supporting shaft 10a in the direction of arrow c, 
while the protrusions if prevent movement of the supporting shaft 10a in 
the direction of arrow d, thus allowing the supporting shaft 10a to be 
rotatably supported so that it does not get removed from the front face 
plate 1. 
When the disk cartridge 5 is not mounted to the magnetic 
recording/reproducing apparatus, the door opening-and-closing mechanism 
with the above-described construction is set such that the opening 2 is 
closed by the door 7, with the lock members 10 preventing free rotational 
movement of the door 7. Therefore, even when the door 7 is pushed with 
something other than the disk cartridge 5, such as when the operator 
accidentally pushes open the door 7 with his finger or a writing material, 
the lock members 10 prevent rotational movement of the door, thereby 
reliably preventing the entrance of foreign matter into the magnetic 
recording/reproducing apparatus from the opening 2. In addition, even when 
an attempt is made to insert a disk cartridge having a sectional shape 
which is different from the sectional shape of the cartridge 5 into the 
opening 2, the disk cartridge contacts the first protrusions 1a and the 
second protrusions 1b, which prevents the disk cartridge from pushing the 
protrusion 10d to be pushed. Therefore, the lock member 10 continues to 
prevent rotational movement of the door 7, thereby preventing accidental 
insertion of a disk cartridge which is not of the regular type. When the 
door 7 is pushed by a regular type disk cartridge 5, the pushing force is 
received by the upper and lower sides of the door 7 through the lock 
portions 10b and 10c of the lock member 10 and the stopper portion 9, 
resulting in less frequent breakage of the rotary shaft 7a of the door 7. 
When the disk cartridge 5 is being pushed into the opening 2 in the 
direction of the arrow of FIG. 2, the protrusions 10d to be pushed 
projecting from both upper ends defining the opening 2 are pushed by their 
respective pushing protrusions 6a of the disk cartridge 5. Therefore, the 
lock member 10 rotates about the supporting shaft 10a as supporting point, 
which disengages the lock portions 10b and 10c and the door 7 from each 
other. Here, the protrusions 10d to be pushed and the pushing protrusions 
6a contact each other at tapers 10e, respectively, so that the lock member 
10 is reliably rotated, even when the disk cartridge 5 is slightly 
displaced in the opening 2. As shown in FIG. 7, when the disk cartridge 5 
is further pushed into the opening and pushes the door 7, the door 7 
rotates around the rotary shafts 7a as supporting points in order for the 
disk cartridge 5 to be held by the holder 3 in the magnetic 
recording/reproducing apparatus. 
When an eject button (not shown) is operated to eject the disk cartridge 5 
from the magnetic recording/reproducing apparatus to the opening 2, the 
door 7 rotates in the opposite direction due to the biasing force of the 
torsion coil spring 8, and the lock member 10 also rotates in the opposite 
direction due to the biasing force of the torsion coil spring 12. As a 
result, the opening 2 is re-closed by the door 7 which is prevented from 
freely rotating by the lock member 10.