Dynamic information storage or retrieval – Dynamic mechanism subsystem – Having power driven transducer assembly
Reexamination Certificate
1999-10-15
2002-01-01
Miller, Brian E. (Department: 2652)
Dynamic information storage or retrieval
Dynamic mechanism subsystem
Having power driven transducer assembly
Reexamination Certificate
active
06335915
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an optical pickup sending device for freely moving back and forth an optical pickup within an information recording/reproducing apparatus such as a disc player so as to read information from an information recording medium such as an optical disc.
There have been known several types of conventional pickup sending devices such as those disclosed in Japanese Utility Model Unexamined Publication No. 5-61861 and Japanese Patent Unexamined Publication No. 6-68619.
FIG. 6
is used to schematically indicate the structure of a conventional pickup sending device disclosed in Japanese Utility Model Unexamined Publication No. 5-61861. As shown in
FIG. 6
, the sending device comprises a pair of guide shafts
2
and
3
for slidably supporting an optical pickup body
1
, a screwed shaft
4
, a rack member
6
supported by two arm members
5
extending from the pickup body
1
. The teeth
6
a
of the rack member
6
are engaged with the screwed shaft
4
. When the screwed shaft
4
is rotated, a relative positional relationship between the teeth
6
a
and the screw shaft
4
will he changed, so as to cause the pickup body
1
to freely move back and fourth along the guide shafts
2
and
3
, i.e., in a radial direction of an optical disc such as a CD (Compact Disc) mounted on a turntable (not shown).
With the pickup sending device shown in
FIG. 6
, although the rack member
6
is elastically urged by the screw shaft
4
through a least spring
6
b
provided in parallel with the arm members
5
, since the teeth
6
a
of the rack member
6
are simply engaged with a part of the circumferential surface of the screwed shaft
4
, an engagement between the teeth
6
a
of the rack member
6
and the screw shaft
4
is apt to collapse even due to a small vibration. As a result, it is difficult for the optical pickup
1
to read information from the optical disc in a correct manner and hence there will be some defects in the obtained information read by the optical pickup
1
.
FIG. 7
is used to schematically indicate the structure of another conventional pickup sending device disclosed in Japanese Patent Unexamined Publication No. 6-68619. As shown in
FIG. 7
, the sending device comprises two guide shafts
8
and
9
for slidably supporting an optical pickup body
7
in a manner such that the pickup body
7
can be freely moved back and forth in the radio direction of an optical disc. A support member
10
is provided on the pickup body
7
. The support member
10
has an engaging pin
12
provided at a front end thereof which is capable of engaging with a screw portion
11
formed integrally with the guide shaft
8
. When the guide shaft
8
is rotated, a relative positional relationship between the engaging pin
12
and screw portion
11
will be changed, so as to cause the optical pickup body
7
to freely move back and fourth along the guide shafts
8
and
9
.
With the pickup sending device shown in
FIG. 7
, since only the front end of the engaging pin
12
is engaged with the screw portion
11
of the shaft
8
, an engagement between such two members
8
is apt to collapse even due to a small vibration. As a result, it is difficult for the optical pickup
7
to read information from the optical disc in a correct manner and hence there will be some defects in the obtained information read by the pickup
7
.
In order to solve the problems existing in the above conventional devices shown in
FIGS. 6 and 7
, there has been suggested an improved structure shown in FIG.
8
. Referring to
FIG. 8
, a half-nut
14
engaged with a screwed shaft
13
, is integrally formed with a holding member
16
extending outwardly from the pickup main body
15
. The inner diameter of the half-nut
14
is made almost the same as that of the screwed shaft
13
, so that it is sure to prevent the half-nut
14
from getting off the screwed shaft
13
.
However, if there is a relative deviation between a pair of guide shafts
17
,
18
on one hand and the screwed shaft
13
on the other, an undesired gouging force will happen since it is difficult to absorb a dislocation caused by the above deviation between the screwed shaft
13
and the half-nut
14
. As a result, there will he an unduly increased load on a driving motor (not shown) for driving the screwed shaft
13
, hence undesirably causing an increase in the starting voltage of the driving motor.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved optical pickup sending device capable of solving the above-mentioned problems peculiar to the above-discussed prior arts.
According to the present invention, there is provided an optical pickup sending device, comprising: an optical pickup for reading information from an information recording medium; a rack member provided in connection with the optical pickup; and a screwed shaft engaged with the rack member for sending the optical pickup along the screwed shaft. In particular, the rack member is formed with a plurality of curved teeth each having a radius of curvature larger than that of the screwed shaft.
In one aspect of the present invention, the rack member is integrally formed with a holder so as to be supported thereby, said holder is engaged in a frame structure which is integrally formed with an arm member extending from he optical pickup and facing towards the screwed shaft.
In another aspect of the present invention, a coil spring is attached onto the holder in a manner such that the rack member is elastically urged against the screwed shaft.
The above objects and features of the present invention will become better understood from the following description with reference to the accompanying drawings.
REFERENCES:
patent: 4742411 (1988-05-01), Horio et al.
patent: 4747004 (1988-05-01), Kukreja et al.
patent: 5198946 (1993-03-01), Kurosawa
patent: 5448438 (1995-09-01), Kasetty
patent: 5682282 (1997-10-01), Kato
patent: 5812347 (1998-09-01), Henke
patent: 6052358 (2000-04-01), Morikawa et al.
patent: 6-068619 (1994-03-01), None
Komiyama Takashi
Muto Akihiro
Ogiwara Yasuo
Uchiyama Kenji
Uchiyama Tetsuya
Arent Fox Kintner & Plotkin & Kahn, PLLC
Miller Brian E.
Pioneer Corporation
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