Floppy disc drive chucking device

Details Floppy disc drive chucking device Floppy disc drive chucking device

1999-09-01

2001-03-27

Tupper, Robert S. (Department: 2652)

Dynamic magnetic information storage or retrieval

Record transport with head stationary during transducing

Disk record

Reexamination Certificate

active

06208487

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a floppy disc drive (FDD) chucking device which uses a reliable and low-cost means for centering a floppy disc for rotation when loading the floppy disc into the floppy disc drive.
2. Description of the Related Art
Record media (typified by floppy disks), that is, disc cartridges, are loaded into a floppy disc drive. A disc cartridge is a case containing a thin record disc. In a floppy disc drive, the record disc is rotated, and input operations of record data and output operations of recorded data are carried out through a write/read window (which opens to the case) provided with a shutter. A floppy disc drive must be capable of allowing easy removal of the record disc contained in the case from the floppy disc drive, precisely aligning the record disc with the axis of rotation of the floppy disc drive during write/read operations, and precisely controlling the rotational speed of the record disc. To achieve these, a chucking device, such as that shown in
FIGS. 5 and 6
, has been conventionally used in floppy disc drives.
A record disc, or a floppy disc, has a center hub at the center portion thereof. In
FIGS. 5 and 6
, the center hub
2
has a substantially square center hole
3
formed in the center portion thereof, and a substantially rectangular hole
4
formed in a peripheral edge portion thereof. The hole
4
is defined by a front edge
4
a
(being formed in correspondence with the front portion of a rotor yoke in the direction of rotation thereof) and an outer edge
4
b
(formed away from the center of rotation of the rotor yoke). In the specification, the direction away from the center of rotation of the rotor yoke is referred to as the outward direction.
A floppy disc drive includes a rotor yoke
101
, which is a ferromagnetic metallic disc rotationally driven by a motor (not shown) in a certain direction (in the direction of arrow D in FIGS.
5
and
6
). A magnetic disc (or a chucking magnet)
102
is affixed to the top portion of the rotor yoke
101
.
A center shaft
103
is provided in a standing manner at the rotational center
0
of the rotor yoke
101
. It passes through a hole
102
a
formed in the center portion of the magnetic disc
102
. It is provided so as to be loosely inserted into the center hole
3
formed in the center hub
2
.
In the specification, the term “loosely” will be used to describe a state in which the center shaft
103
can move freely horizontally and vertically within a predetermined range.
An arc-shaped drive pin through hole
104
is formed in a peripheral edge portion of the rotor yoke
101
, along a circumference of the rotor yoke
101
. An arc-shaped chucking arm
105
is loosely provided in the drive pin through hole
104
. It is formed by molding, along a circumference of the through hole
104
. An upwardly extending drive pin
106
is formed on an end portion (hereunder referred to as the “front portion”)
105
a
of the chucking arm
105
oriented in the rotational direction D of the rotor yoke
101
. The drive pin
106
loosely passes through a front portion opening
102
b
formed in the magnetic disc
102
. It is provided so as to be loosely inserted into the hole
4
formed in the center hub
2
. On the front portion
105
a
are formed flanges
105
c
and
105
c
, which support the front portion of the chucking arm
105
so that the chucking arm
105
can move horizontally and vertically within a predetermined range. When the front portion of the chucking arm
105
is movably supported, the portion of the rotor yoke
101
located adjacent the front portion of the drive pin through hole
104
is loosely disposed between the flanges
105
c
and
105
c.
From a back end of the drive pin through hole
104
formed in the rotor yoke
101
, the other end portion (hereinafter referred to as the “back portion”)
105
b
of the chucking arm
105
extends towards the back, along the top surface of the rotor yoke
101
so as to form an L shape. In a back portion opening
102
c
formed in the magnetic disc
102
, a sliding shaft
108
which protrudes from the top surface of the rotor yoke
101
is received by a receiving hole
105
d
, thereby allowing the back portion of the chucking arm
105
to slide horizontally within a range corresponding to the width of the drive pin through hole
104
, with the sliding shaft
108
as center.
A ferromagnetic plate
109
is mounted to the top portion of the body of the chucking arm
105
, and functions to magnetically attract the entire chucking arm
105
, so that the drive pin
106
is pushed upward at all times.
When a floppy disc is loaded into the floppy disc drive, a record disc is placed on top of the rotor yoke
101
. The center hub
2
of the record disc is magnetically attracted to the magnetic disc
102
, and the center hole
3
formed in the center hub
2
receives the center shaft
103
disposed at the rotor yoke side. Here, the drive pin
106
which protrudes above the magnetic disc
102
does not have to be inserted into the hole
4
formed in the center hub
2
. When the drive pin
106
is not inserted in the hole
4
, it is pushed by the center hub
2
to the level of the lower surface of the center hub
2
, against the force of attraction of the ferromagnetic plate
109
.
Here, within the time the rotor yoke
101
rotates not more than once in the direction of arrow D as a result of starting a motor (not shown), the top portion of the drive pin
106
slidably rotates at the lower surface of the center hub
3
, and moves upward into the hole
4
by the force of attraction of the ferromagnetic plate
109
. When the drive pin
106
has moved upward into the hole
4
, further rotation of the rotor yoke
101
in the direction of arrow D causes the chucking arm
105
to slide in the same direction that the drive pin
106
moves when the drive pin
106
moves away from the rotational center
0
, by the centrifugal force produced by the rotation of the rotor yoke
101
. This causes the drive pin
106
to come into contact with the outer edge
4
b
defining the hole
4
. In addition, it slidably moves forward in the hole
4
by the rotational force of the rotor yoke
101
so as to come into contact with the front edge
4
a
defining the hole
4
. Accordingly, the drive pin
106
comes into contact with and is supported by the front edge
4
a
and the outer edge
4
b
defining the hole
4
.
At this time, the center shaft
103
comes into contact with and is supported by two adjacent sides
3
a
and
3
b
defining the center hole
3
of the center hub
2
. The adjacent sides
3
a
and
3
b
oppose the drive pin
106
, with the rotational center O being located between the two sides
3
a
and
3
b
. When the center of the record disc and the rotational center O of the center yoke
101
coincide when the center shaft
103
is supported by the two sides
3
a
and
3
b
, the chucking operation is completed. When the two centers coincide, the record disc, or the floppy disc, is not decentered, so that it can rotate precisely in accordance with the controlled rotational speed of the rotor yoke
101
.
However, the above-described floppy disc drive chucking device has the following problems. When the above-described chucking arm
105
is used, it is necessary to form a sliding shaft
108
on the rotor yoke
101
. Here, it is difficult to form sliding shaft
108
precisely to a required height. In addition, in order to mount the chucking arm
105
loosely, it is necessary to form a large drive pin through hole
104
. Here, the rotor yoke
101
flexes when drive pin through hole
104
is being formed, resulting in increased surface movement of rotor yoke
101
.
The method of supporting the drive pin
106
by the front edge and the outer edge defining the hole
4
formed in the center hub
2
relies only upon the rotational moment of the chucking arm
105
. Here, sliding friction produced between the chucking arm
105
and the rotor yoke and sliding friction produced between the magnetic head and media prevent the ce

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