Note: Descriptions are shown in the official language in which they were submitted.
Background of the Invention
The invention relates to magnetic disk data storage apparatus
and in particular to such storage apparatus employing flexible magnetic disks
contained in protective envelopes therefor.
. It has previously been proposed to proYide data storage
apparatus which employed a thin flexible magnetic disk contained in an envelope,20such as in Dalziel et al Patent 3,678,481~ In this prior construction, only"~
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105f~i499
1 one side of the magnetic disk was used for receiving infor-
mation and the information was imparted to this side of the
disk by means of a magnetic read/write head. A pressure pad
was axially disposed with respect to the read/write head and
was effective on the other side of the disk.
Summary of the Invention
It is an object of the invention to provide an improved
storage file utilizing a flexible disk encased in a protective
envelope and which allows both sides of the disk to have
information encoded thereon and readable therefrom.
It is a still more particular object of the invention
to provide a pair of read/write magnetic heads on opposite
sides of the flexible disk and improved supporting mechanism
for the disk and more particularly for the protective
envelope for the disk which causes the disk to be in firm
uniform contact with the magnetic head on either side of the
disk so that information may be reliably encoded on or read
from either side of the disk.
In a preferred embodiment, a stationary frame is provided
with opposite slots into which the disk encased in its pro-
tective envelope may be moved. The frame carries a disk
engaging drive shaft and a cover is hingedly mounted on the
frame and carries a rotatable collet for engaging the disk
between the shaft and collet when the cover is closed with
respect to the frame. A U-shaped carriage embraces the disk
and protective envelope and has read/write heads in its two
arms which are adapted to extend through slots provided in
the envelope to engage with the magnetic surfaces on the disk.
The carriage is slidably disposed on
~0972-033 -2-
105~499
1 a vertical stationary support rod, and a rotatable screw
extends through the carriage for moving the carriage verti-
cally whereby to bring the read/write heads to register with
different magnetic tracks on the disk surfaces. A pair of
pads embrace and are spaced from the head assembly on one
side of the disk, and a similar pair of pads are disposed
on the other side of the disk. The pair of pads on one side
of the disk are moved forwardly to move the envelope and
disk in the same direction to bring the disk into contact
with the read/write head on the other side, and a similar
pair of pads are provided on the latter side of the disk
for moving the disk into contact with the read/write head
on the first side of the disk.
Brief Description of_the Drawings
FIG. 1 is a plan view of a flexible magnetic disk with
its enclosing protective envelope which may be used with the
apparatus of the invention;
FIG. 2 is a plan view of the magnetic disk, removed from
its protective envelope;
FIG. 3 is a perspective view of the data storage appara-
tus, of the invention, viewing the data storage apparatus
and the base frame of the apparatus from the back;
FIG. 4 is a perspective view of the base frame of the
storage apparatus, viewing the base frame of the apparatus
from its inside;
FIG. 5 is a perspective view of a cover which is hinged
on the base frame and viewing the cover from its inside;
: FIG. 6 is an exploded view of the disk and
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lOS~499
1 its protective envelope together with movable front pads
(in the front of the figure) and movable back pads tin the
back of the figure) which are supported from the base frame
for moving the protective envelope and disk into recording
and reading dispositions with respect to read/write heads
which are fixed axially of the heads;
FIG. 7 is a side elevational view of the magnetic
disk-envelope assembly together with the front pads (in the
left of the figure) and back pads (in the right of the figure)
which move the disk into recording engagement with the
read/write heads;
FIG. 8 is a perspective view of the base frame, the
pads, the carriage for the heads, and the disk-envelope
assembly, viewing these parts from the back;
FIG. 9 is a side elevational view of the head carriage
;~ and the two read/write heads carried by the carriage and
taken from line 9-9 of FIG. 6; and
; FIG. 10 shown on the sheet of drawings bearing FIG. 5
is a sectional view on an enlarged scale taken on line 10-10
of FIG. 5.
Description of the Preferred Embodiment
Referring to FIGS. 1 and 2 in particular, the magnetic
disk assembly 18 utilized by the data storage apparatus of
the invention may be seen to comprise a magnetic disk 20
disposed within a square envelope 22. The disk 20 is of a
thin flexible material, such as of polyethylene terephthalate
of about .003 inch thickness, and the disk 20 has an unoriented
FE2O3 coating on both sides. The envelope 22 may be of rigid
vinyl sheet material of .010 inch thickness, for example. The
disk 20 has a central opening 24, and the envelope 22 has larger
central openings
:
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105ti499
1 26 in its two thicknesses. In addition, the envelope 22
has aligned radial slots 28 and aligned round openings 30
in its two thicknesses. The openings 30 are adapted to
al:ign with an opening 32 in the disk 20 as the disk 20 ro-
tales within the envelope 22. An assembly of this type is
disclosed in U.S. Patent 3,668,658 issued June 6, 1972,
which may be referred to for more detail.
The data storage apparatus includes a backbone or base
frame 34 having a cover 36 swingably mounted thereon by
means of a hinge 38. The frame 34 is formed with a pair
of opposite downwardly tapering slots 40 for receiving a
cartridge assembly 18. A shaft 42 is rotatably mounted in
the frame 34 and is formed with a rim 44 (see FIG. 4) and
a central countersunk depression 46 on one end. A pulley
48 (see FIG. 3) is fixed on the other end of the shaft 42,
and the pulley 48 is driven from a drive motor 50 located
on the bottom of the frame 34 by means of a belt 52 which
extends around the pulley 48 and the output pulley 54 of
the motor 50.
The cover 36 has a tapered collet 55 rotatably mounted
therein, and the collet 55 is adapted to enter the counter-
sunk depression 46 in the end of the shaft 42 when the cover
36 is swung toward the frame 34 so as to capture a disk 20
between the collet 55 and the rim 44 for driving the disk.
Any suitable latching means (not shown in detail) may be
used for holding the cover 36 in this position clamping
a disk 20 between the collet 55 and the rim 44.
A U-shaped carriage 56 is carried by the frame 34 and
is longitudinally movable on a vertical guide rod 58 fixea
in the frame 34. A lead screw 60 extends
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1056499
l through lug portions 62 and 64 of ~he carriage 56 (see
FIG. 6) and has screw threaded engagement with corresponding
screw threads formed within the lug portions 62 and 64. A
motor 66 is provided on the bottom of the frame 34 for to-
tating the screw 60 so as to move the carriage 56 upwardly
or downwardly on the rod 58.
The carriage 56 has a slot 68 therein which receives
the disk assembly 18 and which is formed by a front arm
portion 56a and a back arm portion 56b of the carriage 56.
Transducer heads 70 and 72 are respectively carried by
- the arm portions 56a and 56b and have their data recording
and reading surfaces on the internal faces of the arm portions
56a and 56b.
Back pads 74 and 76 are disposed on opposite sides of
the carriage 56 on one side of the assembly 18 when in place,
and corresponding front pads 78 and 80 are disposed on
opposite sides of the carriage 56 and on the other side of
the disk assembly 18. The pads 74 and 76 are adapted to be
moved into contact with the envelope 20 at contact areas
74a and 76a in particular; and the pads 78 and 80 are like-
wise capable of being moved into contact with the opposite
face of the envelope 22 at contact areas corresponding to
but just opposite the areas 74a and 76a.
The pads 74 and 76 are swingably disposed on arms 82
and 83 which are fixed to a shaft 84. The shaft 84 is
rotatably carried by the frame 34. An electromagnet 86 is
. .:
provided for rotating the shaft 84, and a magnet armature
88 fixed to the shaft 84 is provided for this purpose.
A leaf spring 90 is fixed at one end to the shaft 84 and
`~ 30 engages at its other end a spring mount 92 that is
.:
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lOSf~49~
1 f:ixed with respect to the frame 34. The mount 92 has a
portion 92a overlying the extreme end of the spring 90 and
has an outwardly extending lug portion 92b that is adapted
to engage the spring 90 at a point considerably closer to
the shaft 84.
The front pads -t8 and 80 are mounted and moved by
mechanisms similar to that provided for mounting and moving
the pads 74 and 76. The pads 78 and 80 are swingably dis-
posed on arms 94 and 95 (see FIG. 6) that are fixed to a
shaft 96 rotatably carried by the frame 34. An electromagnet
98 is effective for rotating the shaft 96 by means of a
magnet armature 100 that is fixed to the shaft 96. A leaf
spring 102 is fixed to the shaft 96, and a spring mount 104
similar to the mount 92 is provided for the spring 102.
The cover 36 carries a leaf spring 106 (see FIGS. 5
and 10) which overlies a pin 108 fixed to the arm 94 carrying
the pad 78 for moving the pads 78 and 80 as the cover 36
is opened.
In operation, the cover 36 is swung outwardly with
respect to the frame 34; and the leaf spring 106, being in
the form of a hook, hooks on to pin 108 and pulls front pads
; 78 frontwardly away from the back pads 74 and 76. The pads
78 and 80 move together with rotation of shaft 96 against
the action of spring 102. A disk assembly 18 is then slid
downwardly in the slots 40 so as to position the central
., .
opening 24 in the disk 20 approximately in alignment with
the counterbore 46. The cover 36 is swung inwardly toward
the frame 34, and the collet 55 is thereby moved through
the disk opening 24 and into the counterbore 46. It will
be noted that the collet 55 is tapered, and this
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.. . . . .
105~499
1 movement of the collet 55 into the counterbore 46 has the
effect of centralizing the disk 20 with respect to the cen-
tral axis of the collet 55 and of the shaft 42. The disk
20 is at this time gripped between the collet 55 and the
rim 44 on the shaft 42 so that the disk 20 is rotated with-
in the stationary envelope 22 by means of the motor 50 driv-
ing through the belt 52 and the pulleys 54 and 48. The
cover 36 is held in this position by suitable latching mech-
anism ~not shown in detail).
Initially, neither of the electromagnets 86 and 98
is energized, and the springs 90 and 102 are approximately
flat and hold the pads 74, 76, 78 and 80 in loose engagement
(with substantially zero clearance) with the exterior
surfaces of the envelope 22. Under these conditions, neither
of the magnetic surfaces on the disk 20 engages with the
read/write surface of the transducer 70 or the transducer 72
on the inner surfaces of the arm portions 56a and 56b.
When it is desired that information shall be either read
from or written on the front surface 20a of the disk 20,
the electromagnet 86 energized (see FIG. 7). The armature
; 88, shaft 84 and arms 82 and 83 are then moved by the action
of the electromagnet 86 in the counterclockwise direction
as seen in FIG. 7 so as to forcibly apply the pads 74 and
~ 76 on the contact areas 74a and 76a of the adjacent outer
- surface of the envelope 22. This movement of the parts 88,
84, 82, 83, 76 and 74 is against the resilient action of
the leaf spring 90 which then pivots about the abutment por-
tion 92b of the mount 92 with the lower end of the spring 90
bearing against the portion 92a of the mount 92. The spring
; 30 go is then in its dotted line condition as shown in FIG. 7.
.
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1 Since the abutment poxtion 92b located relatively close
to the shaft 84 bears on the leaf spring 90, it is apparent
that only the short length of the leaf spring 90 between the
shaft 84 and the abutment portion 92b is effective to pro-
v:ide a return force on the shaft 84; and this return force
thus is relatively high due to the short length of the
spring 90 that is thus utilized.
The pads 74 and 76 in being forced against the disk
assembly 18 move the front disk surface 20a against the
transducer 70 carried by the arm portion 56a of the carriage
56. The transducer 70 extends through the slot 28 in the
side of the envelope 22 adjacent the cover 36; and, therefore,
as the disk 20 rotates, information may be written on this
disk surface 20a or may be read from this disk surface.
Since the pads 74 and 76 are located on oppostie sides
of the transducer 70, the disk 20 is moved into firm
engagement with the transducer 70 so that transducer 70
slightly penetrates disk 20; and dependable writing or
reading occurs using the transducer 70.
A restraint on the movement of the disk assembly in
the direction toward the arm portion 56a and under the
influence of the pads 74 and 76 is provided by the pads
78 and 80. The pads 78 and 80 are moved slightly to the
left as seen in FIG. 7, and the shaft 96 and arms 94 and
; 95 move correspondingly in the counterclockwise direction.
This movement is against the flexing action of the spring
.
102 which in this case does not contact the abutment
portion 104b but is out of engagement with this abutment
portion, with only the return bent portion 104a of the
mount 104 being effective on the extreme lower end of the
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~os~499
1 leaf spring 102. The complete length of the spring 102 is
thus flexed, as is shown in dotted lines in FIG. 7, and
the spring 102 provides less return force on the shaft 96
than is provided by the spring 90 on the shaft 84. The
pads 78 and 80 thus bear with a very light pressure on the
disk assembly 18 just sufficient to stabliize the disk as-
sembly 18 in its proper position with the disk surface 20a
bearing with the proper pressure on the transducer 70 for
a reliable reading or writing action by the transducer 70.
The actual force of the transducer 70 on the disk 20 is
actually a function of the resilience of the disk 20 since
the disk 20 is bowed around transducer 70 against the re-
silience of the disk. The disk 20 is very thin as above
described and thus has a low spring constant or resilience,
and the disk 20 can be moved more or less into the transducer
70 with a relatively great tolerance while still maintaining
; reliable reading and writing action. It may be noted in
this connection that the portion of the envelope 22 at the
side edges of the slot 28, through which the transducer 70
extends, imparts some support to the disk 20.
When it is desired to discontinue the reading or writing
action with respect to the disk sur~ace 20a, the electro-
magnet 86 is de-energized; and the parts return to their
positions shown in FIG. 7. As above mentioned, the spring 90
provides a greater return force on the shaft 84 than does
the spring 96, when the electromagnet 86 is energized; and,
therefore, the spring 90 is effective to rotate the shaft
84 and connected parts in the clockwise direction. At the
same time, the straightening action of the spring 102 brings
the parts connected with the shaft 96 back to
R0972-033 -10-
105f~i4~9
1 their FIG. 7 neutral positions.
When it is desired that the back side 20b of the disk
20 be used for the reading or writing action, utilizing the
txansducer 72; the electromagnet 98, instead of the electro-
magnet 86, is energized. The pads 78 and 80 in this case
move the other side 20b of the disk 20 in rather forceful
engagement with the active surface of the transducer 72,
and the side 20b of the disk 20 is then in effective engage-
ment with the transducer 72 in the same manner that the
transducer 70 was made effective when the electromagnet
86 was energized. With the electromagnet 98 being energized,
the pads 74 and 76 are the backup pads and assure the proper
pressure of the disk 20 on the active surface of the trans-
ducer 72. In this case, both of the shafts 84 and 96 and
the connected parts rotate slightly in the clockwise direction,
as seen in FIG. 7, similarly as in the first mentioned case
in which the direction of rotation of the shafts 84 and 96
was in the counterclockwise direction.
It will be apparent that, in order to access different
tracks on either of the disk faces, it is only necessary
that the screw 60 be rotated so as to move the transducer
70 or the transducer 72 longitudinally within the slot 28
in which the transducer is positioned. This is preferably
done while the transducer 70 or the transducer 72 remains
in contact with the disk 20.
The data storage apparatus of the invention advant-
ageously utilizes the carriage or head 56 carrying the
- read/write transducers 70 and 72 which is fixed in directions
normal to the disk 20 by screw 60 and rod 58, being movable
only longitudinally with rotation of screw 60
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~056499
so that the transducers 70 and 72 may be effective with
2 respect to different tracks on the disk surfaces. The
3 pads 74 and 76, which are spaced somewhat from the transducer
4 70 along the surfaces of the disk 20, are effective to apply
force on to the disk at the spaced contact areas 74a and
6 76a so that the disk 20 is bent around the active surface
7 of the transducer 70 to have a firm reliable reading and
8 writing engagement with the opposite surface of the disk.
9 In this case, the opposite pads 78 and 80 provide a rela-
tively light restraining force on the disk assembly 18.
11 This same action occurs but in the opposite manner when the
12 electromagnet 98 is energized to render the pads 78 and 80
13 the disk assembly moving means.
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