Chucking device in FDD

Dynamic magnetic information storage or retrieval – Record transport with head stationary during transducing – Disk record

Reexamination Certificate

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Reexamination Certificate

active

06259582

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a chucking device in an FDD (floppy disk drive) capable of preventing an eccentric rotation of a floppy disk in a positive and inexpensive manner at the time of loading the floppy disk into the FDD.
2. Description of the Related Art
A recording medium, typical of which is a floppy disk, is loaded into an FDD in the form of a disk cartridge in which a thin film-like recording disk is received in a case, the recording disk is rotated within the FDD, and recording data are inputted and outputted through a write/read window formed in the case and having a shutter. It is necessary that the recording disk be capable of being removed easily in its received state in the case and aligned exactly with a rotational axis of the FDD at the time of write or read and that the rotating speed thereof be controlled accurately. To meet these requirements, such a chucking device as shown in
FIGS. 6 and 7
has heretofore been used for the FDD.
A center hub formed by a ferromagnetic metal disk is centrally mounted on a recording disk of a floppy disk. As shown in
FIGS. 6 and 7
, a generally square central aperture
3
is formed centrally of the center hub which is indicated at
2
, and a generally rectangular drive pin aperture
4
is formed in a peripheral position of the center hub. The drive pin aperture
4
has a front edge
4
a
at a front position in a rotational direction of a rotor yoke and an outer edge
4
b
in a direction (“outer” hereinafter) away from a rotational center of the rotor yoke.
On the other hand, the FDD is provided with a rotor yoke
101
which is constituted by a ferromagnetic metal disk and which is rotated in a certain direction (indicated at “D” in the figures) by means of a motor (not shown) Onto the rotor yoke
101
is fixed a magnetic disk (chucking magnet)
102
.
A center shaft
103
is erected at a rotational axis O of the rotor yoke
101
. The center shaft
103
extends through a central opening
102
a
of the magnetic disk
102
and is inserted loosely into the central aperture
3
of the center hub.
The term “loosely” as used herein indicates a freely movable state in both horizontal and vertical directions and within a predetermined range.
In the peripheral portion of the rotor yoke
101
is formed a drive pin through hole
104
along the circumference, and a chucking arm
105
formed arcuately along the circumference is loosely fitted in the drive pin through hole
104
. An upwardly extending drive pin
106
is formed at a front end portion (“front portion” hereinafter)
105
a
of the chucking arm
105
facing the rotational direction D of the rotor yoke
101
. The drive pin
106
extends loosely through a front aperture
102
b
formed in the magnetic disk
102
and is inserted loosely into the drive pin aperture
4
of the center hub. At the front portion
105
a
of the chucking arm
105
are formed two flanges
105
c
which hold loosely the rotor yoke
101
portion located around the front portion of the drive pin through hole
104
and which support the front portion of the chucking arm
105
so as to be freely movable in both horizontal and vertical directions and within a predetermined range.
On the other hand, the other end portion (“rear portion” hereinafter), indicated at
105
b
, of the chucking arm
105
extends backward of the upper surface of the rotor yoke
101
at an approximately right angle from the rear end of the drive pin through hole
104
, and within a rear aperture
102
c
formed in the magnetic disk
102
a pivot shaft
108
projecting from the upper surface of the rotor yoke
101
is received in a receiving aperture
105
d
so as to be pivotable horizontally about the pivot shaft
108
and within the width range of the drive pin through hole
104
.
A ferromagnetic plate
109
is mounted on the body of the chucking arm
105
, whereby the whole of the chucking arm
105
is attracted magnetically by the magnetic disk
102
and the drive pin
106
is pulled upward at all times.
Upon loading of a floppy disk into the FDD constructed as above, the recording disk is placed on the rotor yoke
101
, the center hub
2
mounted on the disk is attracted magnetically by the magnetic disk
102
, and the central aperture
3
of the center hub receives the rotor yoke-side center shaft
103
therein. At this time, the drive pin
106
projecting upward from the magnetic disk
102
need not be inserted into the drive pin aperture
4
of the center hub. With the drive pin
106
not inserted into the drive pin aperture
4
, the pin
106
is pushed in by the center hub
2
up to the lower surface level of the center hub against the attractive force induced by the ferromagnetic plate
109
.
In this state, when a motor (not shown) is turned ON, causing the rotor yoke
101
to rotate fully once at most in the D direction, the top of the drive pin
106
slides on the lower surface of the center hub and is received in the drive pin aperture
4
, within which the drive pin rises by virtue of the attractive force of the ferromagnetic plate
109
. As the rotor yoke
101
further rotates in the D direction in this state, the drive pin
106
comes into abutment with a front edge
4
a
of the drive pin hole
4
formed in the center hub
2
, so that the chucking arm
105
rotates in a direction away from the rotational axis O, centered on the pivot shaft
108
and the drive pin
106
comes into abutment with the outer edge
4
b
of the drive pin hole
4
. This state will hereinafter be referred to as “front-outer support.”
At this time, the center shaft
103
is supported by being abutted against two adjacent sides
3
a
and
3
b
of the central aperture
3
of the central hub on the side opposite to the drive pin
106
with respect to the rotational axis O and in this state the center of the recording disk and the rotational axis O of the rotor yoke
101
coincide with each other to complete chucking. In this state the recording disk of the floppy disk can rotate while exactly following up a controlled rotating speed of the rotor yoke
101
.
In the use of the chucking arm
105
, however, it is necessary to form the pivot shaft
108
on the rotor yoke
101
and in this case it is difficult to adjust the shaft height accurately. Besides, for loose mounting of the chucking arm
105
it is necessary that the drive pin through hole
104
be formed large, and there occurs a distortion at the time of forming such a large aperture by machining, thus giving rise to the problem that the surface oscillation of the rotor yoke
101
increases.
In the chucking arm
105
, moreover, since the foregoing front-outer support relies on only the rotational moment of the arm, the recording disk sometimes shifts to a continuous rotation as it is without abutment of the center shaft
103
with two adjacent sides
3
a
and
3
b
of the central aperture
3
in the center hub due to, for example, the influence of a sliding friction induced between the chucking arm and the rotor yoke
101
or a sliding friction between the magnetic head and the recording medium. In this state the recording disk continues an eccentric rotation, giving rise to the problem that there occurs an error in writing and reading of data.
There has also been the problem that the mounting of the chucking arm
105
is troublesome and that therefore the manufacturing cost increases.
SUMMARY OF THE INVENTION
The present invention has been accomplished for solving the above-mentioned problems and it is therefore an object of the invention to provide a chucking device in a floppy disk drive which realizes the foregoing front-outer support in a positive and inexpensive manner without using the conventional chucking arm involving many problems and which thereby prevents an eccentric rotation of a recording disk and always ensures correct writing and reading.
In order to solve the above-mentioned problems, according to the present invention there is provided a chucking device in a floppy disk drive, comprising: a rotor yoke adapted to rotate i

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